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GYCLOPEEIA OEUSEEEL‘AETN,
’ filenhemiml an} (lilgzmiml,
MANUFACTURES, MINING, AND‘ ENGINEERING,
EDITED BY CHARLES IOMLINSON.
VOL. II.
HAMMER TO ZIROONIUM,
Q Q ‘
O 0".
I
THE WHO‘LE HILUSTRéTED BY FORTY STEEL EN GRAVIN GS,
AN D TWO THOUSAND FOUR HUNDRED AND SEVENTY-SEVEN WOOD ENGRAVINGS.

GEORGE VIRTUE 85 00., LONDON 86 NEW YORK.
18541.
LONDON 2
3B. cnnbfigamma, BREAD STREET HILL’. '5 '
I.
i (
1 \ r 4'1.
‘4'
cigar.
Q) S~Zlfid$ Iii DE
L‘)
S'~1‘é ‘t5’
5%L3fi
TO
WILLIAM ALLEN MILLER, Esu; M.D., F.R.S.,
. PROFESSOR OF CHEMISTRY IN KIN G’S COLLEGE,‘ LONDON.
MY DEAR SIR,
On the completion of this Cyclopaedia of Useful Arts, &0., it is
with peculiar satisfaction that I dedicate to you the Second Volume of a work,
throughout the whole of which I have had the advantage of being able to consult
you ‘on points connected with Chemical Art. A similar privilege, with respect
to Mechanical and Engineering subjects, was granted me by our regretted friend,
the late- Professor Cowper, to whom the first volume of this Cyclopaedia was
dedicated.
Such assistance as this may be some excuse for my temerity in ’ undertaking,
four years ago, to prepare so comprehensive a Work ‘as the present. 1 have been
also indebted to some‘ other valued friends for advice and assistance: namely,
W. H. HATCHER, Esq; Dr. GEORGE WILSON, of Edinburgh; E. L. GARBETT, Esq ;
GEonGE DODD, Esq.; and CHARLES COWPER, Esq. The liberality and kindness of
various manufacturing firms are acknowledged in the body of the work; and I have
also been careful to give the titles, &c., of such books, and the names of such persons,
as have afi'orded me information.
Still the task of planning and executing the great bulk of the work has
necessarily fallen upon me. I am aware of many imperfections in it (some of
which are due to the pressure arising from the plan of publication in monthly
numbers); but it has been my endeavour not to aim above the powers of my own
mind, or the capacities of my readers, but simply to present a popular exposition
of the Useful Arts and Manufactures.
of the standard which should be maintained in popular instruction, it may be
But as I form a somewhat high estimate
said that in some cases, I have entered too minutely into the science of technical
iv ' - DEDICATION. “'
subjects to adapt them for popular teaching. Such, however, is not my experience.
If a work so purely scientific as my “ Introduction to the Study of Natural
Philosophy ” could find, within a very few years, as many as 457,000 readers, I think
I am justified in supposing that there is a very large class of persons to whom
intellectual food is as necessary as food for the body, and who require fresh supplies
of the one as much as of the other. If so, it is evidently the duty of writers
and publishers ‘to see that ’ this intellectual food be wholesome, nutritive, and well
adapted to the wants of persons whose limited means forbid a large supply. Readers
of this class have not, like your pupils, the opportunity of following out, in a me—
thodical manner, the principles of science which form the true and only basis of
technical knowledge. Such invaluable instruction is seldom within their power, and
they should therefore find in the books which enterprising publishers i ‘place within
their reach, so full and complete an enunciation of principles as ‘to render details
easy and processes intelligible.
If you will accept a work which has such modest claims to the attention ‘of
men like yourself, you will strengthen the motives which, during many years, have
increased my respect for you as a Christian philosopher, and my "affection for you
/
as a friend.
I remain, _ \
My dear ,Sir,
Your attached Friend,
I cnnnnnsx TOMLINSON.
Bnnronn Pnxcn, Amrrmm. SQUARE,
May, 1854.
' that of several tons to a fraction of an ounce.
OYOLOPEJDIA OF USEFUL ARTS,
jflizrhttiml nth Etrmiml, .
MANUFACTURES, MINING AND ENGINEERING,

HAMMER. The hammer is perhaps the most
remarkable and valuable of all the implements which
man employs in moulding and submitting to his use
the various objects around him. It illustrates the
principle of the permanence of the force of communi-
cated motion; it constitutes the force of impact, and
is the most powerful of weapons. “ Were there no
tendency to permanence in the force of motion which
his hammer acquires in its descent, its power on the
substance which the artificer seeks to shape out
would only be the same as though he were to lay it
gently down upon it: its impact would be no greater
force than the pressure of its weight. So far is this,
however, from being the case, that, as it is well known
to the workman, a slight blow from the lightest ham-
mer is sufficient to abrade a surface which the direct
pressure of a ton weight would not make to yield.
There is no force in nature comparable to that of
impact.”1
The term hammer is usually applied to the well-
known tool consisting of an iron head fixed crosswise
upon a handle of wood; but the hammers employed
in the useful arts are very varied in form, and the
weights of individual examples may be estimated from
The
largest hammer is the helve, or for'ge-lzammer, used in
the operation of shingling in the manufacture of iron .-
this weighs from 4! to 8 tons. The helve is also used
in forging sleel ingots; but when they are sufliciently
reduced by this means, the it'll-hammer comes into
operation, and is made to move with great rapidity
under the action of springs instead of by gravity
alone.
In the ordinary practice of FoEerNe, the smith
employs a variety of hammers with the parses or nar-
row edges made in different ways, either at right
angles to the handle, parallel with the same, or ob-
lique: but the work done by these hammers is often
accomplished with more precision by what are called
sel-lzamr/zers : those with flat faces are made like ham-
mers, and usually with similar handles, and for the
convenience of reversing are not wedged in: these
tools, instead of striking, are struck upon the work
with the sledge-hammer. Other similar tools, with
broad faces, are called jlallers : top tools, with narrow
(l) Moseley: “ Illustrations of Mechanics.” Third Edit. 1846.
You H


round edges like the pane of the hammer, are called
lop-fallers: they are held to the work with hazel-
rods, as noticed in the article CUTLERY, where the
hammers used by the Sheffield cutlers are described.
The hammers used in forging blanks for files, and for
cutting the teeth, are described under FILE. The
banal-hammer used by the smith is of such weight
that it may be governed with one hand at the anvil.
The sleclge-lzammer and the more/rep, or verlz'eal hammer,
are noticed in FonGINe. The sledge-hammer has it‘
varieties, which usually consist of the ap-lzaml sledge,
which is used with both hands, and seldom lifted
above the head, and the about-sledge, which is held
by both hands at the furthest end of the handle, and
being swung at arm’s length over the head, is made
to fall upon the work with as heavy a blow as pos-
sible. Referring to the sledge, Mr. Holtzapifel re~
marks :—-“ It is used ap—lzaml for light work; the
right hand being slid towards the head in the act of
lifting the hammer from off the work, and slipped
down again as the tool descends : and the conditions
are scarcely altered when the smith swings the ham-
mer about in a circle, the signal for which is ‘About
sledge ;’ whereas when, in either case, the blows of
the sledge-hammer are to be discontinued, the fire-
man taps the anvil with his hand-hammer, which is,
I believe, an universal language.” The rlvelz'ag—
lzammer is the smallest used by smiths.
In the practice of forging, small tilt-hammers to be
worked by the foot have often been introduced; but
they are not successful, because, when one man has
to manage the whole, his attention is too much
divided, nor is his strength equal to the work. The
best form of these lz'jl-lzammers is that called l/ze
Oliver, Fig. 1118. “ The hammer head is about 2-;—
inches square, and 10 inches long, with a swage tool,
having a conical crease attached to it, and a corre-
sponding swage is fixed in a square cast-iron anvil
block, about 12 inches square, and 6 deep, with 1 or
2 round holes for punching, &c. The hammer-handle
is from 2 to 2% feet long, and mounted in a cross‘
spindle nearly as long, supported in a wooden frame,
between end screws, to adjust the groove in the
hammer-face to that in the anvil-block. A short arm,
5 or 6 inches long, is attached to the right end of the
hammer axis, and from this arm proceeds a cord to a
13
Z ‘ HARBOUR—HARDWARE-—HARPOON—H AT.
spring-pole overhead, and also a chain to a treadle a
little above the floor of the smithy. When left to
itself, the hammer-handle is raised to nearly a vertical
position by the spring, and it- is brought down very
readily with . 'the'lfoot, "so asjto give-good hard," blows






Fig. i118. THE OLIVER.
at the commencement of moulding the objects, and
then light blows for finishing them.” Mr. Holtzapfi'el
saw this machine at work making long stout nails,
intended for fixing the tires of Wheels, secured within
the felloes by washers and riveting: the nails were
made very nicely round and taper, and were forged
expeditiously.
The misz'rzg-kammer, for raised works in metal, is
rounded at the edge, and of various forms. The
pZam's/zz'nqJm-mmer has a flat ‘smooth face; the gold-
éeater’s hammer, a’ somewhat rounded one; the has/c-
izammer, for correcting distortions which so commonly
occur in hardening steel goods, terminates at each
end in an obtuse chisel edge. The hack-hammer used
for hacking grindstones is a small adze of 2. or 3 lbs.
weight, but longer andmore curved- in the blade, and
with a very short handle. Its use is to hack or notch
the high places which occur large g'rindstones, in
regular work, and arise from unequal wear._- For this.
purpose the high places are‘ marked by holding a
piece of chalk or charcoal steadily upon the horse,
and bringing it gradually near the stone before it
comes to rest, the strap having been thrown off. The
grinder then cuts shallow oblique furrows, about an
inch apart, in the‘ high places denoted by the marks,
and crosses them with others so as to produce a
chequered surface. On again using the stone the
' greatest wear occurs at these roughened places, and
thus the stone is restored to its true form.
The verzeerz'rzg-lmmmer is of iron, with a very wide
thin pane; but it is often formed of wood.
The STEAM—HAMLEEB. will be described under that
head.
HARBOUR is the general name given to any haven
or port communicating with the sea, or with a navi-
gable river or lake of sufficient depth to float ships of

considerable size. A good harbour should be free
from rocks or shallows: the opening should be of
sufiicient extent to admit large ships at all times of
the tide :- it should have good anchorage ground, and
be easy of access, and well defended from the violence
of_ the'wind and of the sea: it should be sufficiently
fcalpa’cious for the reception of the shipping of different
" nations‘, and deep enough to allow ships to lie close
l alongside quays or piers, that the expense and incon-
. : 'v'enie‘nee of loading and unloadingby means of lighters
_ may be avoided: it should be furnished with a good
lighthouse, and have proper rings, posts, moorings,
-&c., to remove or secure vessels. Portsmouth, Mil-
ford Haven, and the Cove of Cork, are the finest
harbours in the British Islands, and are surpassed by
few, if any, in the world. The accompanying steel
engraving represents the harbour of Whitehaven in
‘Cumberland, situate at the upper end of a small
creek of the Irish Sea. This harbour is spacious and
commodious, having seven piers extending into the
sea in different directions, and affording ample secu-
rity to shipping. Attached to the harbour is a patent
slip; there are two lighthouses at the entrance, and
a third situate on the promontory of the Bee’s Head,
3 miles to the south-west. The commerce of this
harbour is very extensive.
HARDWARE, a term applied to goods manufac-
tured from metals, such as iron, steel, copper, brass,
&c. Birmingham and SilBfllBld are the chief seats of
the manufacture in this country.
HARPOON, or HAnrmG-Inon, a javelin'used for
piercing whales in the whale-fishery: it has a broad,
flat, triangular, barbed head, sharpened so as to pene-
trate easily, and a shank about 2 feet long, to the
extremity of which is fastened a long line coiled up
in the boat, so that it may run out easily without
entangling. See OIL.
HARTSHORN. See AMMONIA.
HAT. The manufacture of hats brings into
operation the curious and interesting process of
‘felting, which is the interlacing of animal fibres so
as to produce, without weaving, a dense and compact
cloth. This is caused by the peculiar structure of
the hair and wool of animals, which though appa-
rently smooth and regular, may be detected under
the microscope as notched or jagged at the edges,
the teeth invariably pointing upwards, that is, from
the root towards the point. From a similar example
in the vegetable world, namely, an awn of b ley,
we find that where this notched structure exists, the
fibre when rubbed will movein one idi'rection only.
An awn of barley root upwards travel up the
coat sleeve, by the slight friction between it and the
arm. The same kind of motion, though inferior in
degree, is possessed by fibres of clean wool and hair,
so that when subjected to gentle friction, assisted by
moisture, the fibres mat together and form the kind
of cloth called felt. The felting property of wool is
greatly assisted by the crinkled or zig-zag figure of
the fibre, which is retained with great pertinacity, so
that if drawn out straight, it immediately contracts
again on being let go; thus the forward motion of


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the fibre, under friction, is partly counteracted, or
converted into a circular or zig-zag motion, which is
just that which most completely effects the matting
together of the various fibres. So great is this
tendency, that in a flock bed or mattress the carded


Fig. 1119. A FIBRE or SAXONY LAMBS’-WOOL, HIGHLY
maenrrrnn.
wool of which it is made is constantly felting itself
into knots, and requires to be pulled apart or to be
carded afresh at intervals. Wool in the yolk, or
with the natural grease adhering to it, cannot be
felted, the roughness of the fibre being in that case
filled or smoothed over by the oil.
A remote origin is ascribed to felt, which is said
to have been the lana coacz‘a of the ancients, worn
as cloaks by soldiers, and to have been the material
of the Lacedemonian hats. But the word rendered
fiell by some writers, is by others translated lcnz'llccl
wool, therefore, without occupying ourselves with the
early portion of its history, it may be sufficient to
state, that towards the close of the sixteenth century
there is no doubt of its employment, for beaver
bats were then in use in England, and became so
popular, that in the next century Heywood, writing of
varieties of head gear, concluded with, “ But of all
felts that may be felt, give me your English beaver.”
An old hatter informed the writer, that in his
youth an annual festival was held on St. Clement’s
Day, (23d November,) this saint being the reputed
inventor of felt, and that in Ireland and other Roman
Catholic countries, the hatters still hold their festival
on this day. St. Clement, perhaps, was the saint
who is said to have put carded wool in his sandals to
protect his feet on a pilgrimage, and who found at
its close, that the wool had felted itself into cloth.
Beaver hats were at first regarded as a great
curiosity, and fetched a high price, considering the
value of money in those days. In 1585, Stubbs
wrote, “ And as the fashions be rare and strange, so
is the stufle whereof these hattes be made divers
also; for some are of silke, some of velvet, some of
taffatie, some of sarcenet, some of wool], and, which
is more curious, some of a certain kind of fine haire.
These they call beaver hattes, of xx, xxx, or xl
shillings price, fetched from beyonde the seas, from
whence a greate sorte of other vanities doe come
besides.”
The supply of beaver for this manufacture is re-
ceived through the Hudson’s Bay Company, but
owing to the gradual extermination of the beaver in
many countries where it was once common, and the
consequent failure in the imports of beaver, the fur
of several other animals is come into use as a substi-
tute. Thus the hair of the Coypou, whose skin is
sold as nalrz'a s/cz'n, that of the musquash or musk-

rat, the fine down from the back of the common
hare, and the fur of the rabbit, are all used in the
hat manufacture. The furs in question form the nap
of the hat; the body of the hat is made of lamb’s
wool, carefully washed, scoured, dried, and carded.
The woolly hair of the Llama, or Vicuna, a species
of camel, native of the Andes, is also used for the
purpose. The structure of some of these hairs is
shown in the following figures.
Fig. 1120. STRUCTURE or BEAVER-DOWN.

- ma...
4/
Fig. 1121. musauasn.
Fig. 1122.
NUTRIA.


Fig. 1123.
HA ans’mown.


Fig. 1124. nannr'rs’ FUR.
The manufacture of hats from beaver, or from the
furs used as substitutes, is conducted in the following
manner; but it must be premised, that the demand
for such hats is now comparatively small, on account
of the perfection to which silk hats have been
brought. The first operations belong to the furrier,
and consist, first, of the cleansing of the skins by
thorough washing in soap and water, after which the
long coarse hairs are pulled out by a woman seated
on a low stool, with the skin fastened to her knee by
a strap passing over the skin and under the foot.
She pulls out the long hairs by the roots with a
jerking motion, seizing them between the thumb and
the edge of a blunt knife. After all the long hairs
are removed by this process, which is called pulling or
forcing, the fine down or fur is next shorn from the
skin by a sharp blade, applied either by hand or by
machinery. By a simple but effective contrivance,
the fur is then sorted into difi’erent degrees of fine-
ness. A current of air conveys it along a horizontal
trunk, and as it floats along, the filaments are
separated, and are carried to a greater or less
distance according to their weight, the coarse and
heavier filaments falling down first, and the finer and
lighter continuing longer afloat, and being deposited
considerably in advance. Thus, when the blast of
air ceases, it is only necessary to open the trunk
and select the various qualities as they lie ready
sorted to the hand.
The succeeding operations are carried on in the
beaver-hat factory. According to the kind of bat
required, the beaver, some inferior fur, or lamb’s
wool, are selected for operating on. The beaver hat,
properly so called, consists of a body or foundation
of rabbit’s fur and a beaver nap, but the latter is
frequently mixed with some other fur. Another kind
n 2
4, HAT.
, surface towards the fur.
of hat is made with the body of lamb’s wool, and the
nap of musquash, nutria, or some cheaper fur than
beaver. This is called a plate hat, to signify, pro-
bably, that the outer layer only is of fur, the inner
of felted wool, just as in plated articles the outside
only is of the genuine material. A third kind of hat
is the fell hat, in which the body is of wool and no
nap is added. Supposing the hat to be one in which
the body is of wool, and the plate or nap is of a
superior kind, the processes are as follows. In the
factory visited by the Editor, the fur is weighed out,
mixed, and formed into a nap, in a low unventilated
apartment, where every precaution is adopted to
keep the air stagnant, that none of the precious
material be wafted away and lost. One side of
this apartment is occupied by a broad bench or
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Fig. 1125.
BOWING.
counter, partitioned off into spaces of about five feet
every way, each space being lighted by a window,
constructed so as not to open. See Fig. 1125. Before
each window stands a workman, performing the deli-
cate and ingenious operation of lowing the fur, and
making it into a nap. He first weighs out, say an
ounce of beaver-down, a quarter of an ounce of
musquash, and the ,same quantity of cotton wool.
These three substances are placed on the bench in a
heap, which‘ might be covered with the palm of the
hand. He then takes in his left hand a bow about
seven feet long, which is also kept steady by means
of a cord suspended from the roof, and gives repeated
and sudden twangs to the string, using for this
purpose a wooden pin with a projecting knob. At
every vibration of the string on the tangled heap of
fur, a quantity of the filaments spring up several
inches, are carried a little to the right of the bow,
and fall down within certain limits, in which they are
detained by a wicker frame-work, called the basket,
shaped like a fireguard, and set up with its concave
By this process of bowing,
all the fibres of the tangled mass are separated and
equally distributed over a surface of several square
feet in the course of a few minutes. The operation

is repeated a second and third time, and such is the
dexterity attained by the workman, that he seems
able by the vibrations of his string to make the
filaments fall into any required shape or position.
When the fur is thus distributed into a large oval
sheet, it is next pressed together so as to condense
or lzam’en it. The convex surface of the basket, and
afterwards the hands, are employed to mat and inter-
lace the fibres of the sheet of napping, as the fur is
now called; and in order to complete the process, a
skin of leather is interposed, and rubbed firmly with
both hands, with a somewhat jerking motion, the skin
being taken up and put down again in a different
position several times. The use of this skin, called
the hardening s/n'n, tends to complete the interlacing
of the fibres of the nap, and to produce a felt like
thin flannel. The sheet of napping can now be
handled with impunity. It is along oval sheet, similar
to No.1 in Fig. 1126, and this is folded together, first
sideways, as in
No.2,andthen @ g5
endways, as in F1, 1 126 '
N o. 3, and is g. '
measured while thus twice doubled, against the hat
body, or foundation on which it is ultimately to
be placed. Hat-bodies are supplied to many of the
town manufactories from provincial works which
deal only in this article. ‘They are commonly of
wool, formed into conical caps, about fourteen
inches high, and fifteen inches wide at the base.
They are formed by the felting processes which
come so largely under notice in this manufacture.
If the sheet of napping, doubled as above, is deeper
than the conical cap, or hat body, a portion of it is
torn away and bowed again. From this waste a
smaller sheet of napping is formed, and cut into
strips for the brim of the intended hats, and for a
thicker supply of nap to those parts which are most
exposed to wear. At this stage of the operations,

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J j u ,1. \ . v.1 ._.
in, 1,1, fililflflnnmnw I .\ .y . _ :4
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Fig. 1127. HAT-MAKER’S BATTERY-
the workman proceeds to the hat-maker’s battery,
where, around an open iron boiler, there is accommo-
datlon for seven or eight men to work at a bench of
HAT. 5
mahogany, sloping towards the boiler. This is
charged with soft water, containing about half a gill
of sulphuric acid, and beer-grounds, or a handful of
oatmeal, the former assisting in the removal of
unctuous matters from the wool or fur, the latter
correcting, it is said, the corrosive tendency of the
acid. The whole is kept at the boiling point by a
fire below, and the workmen pursue their task amidst
clouds of steam. The conical hat body is first held
in the hot liquor, and when sufiiciently soft is laid
on the bench; a piece of beaver napping, sufficient
to cover it, is gently laid on, the hat body is then
turned over, and the napping, which is double, is
unfolded and made to cover the other side also.
The napping is sprinkled with hot liquor by means
of a brush called a stopping brush, and is further
worked with the hands, while hot liquor is occasion-
ally poured into the body. Fresh nap is added from
time to time, and that which is to form the under
surface of the brim is put on when the hat body is
turned inside out. A hair-cloth is next laid upon the
bench, and upon this the napped body is rolled with
a rolling pin, and worked in various ways by the
hand, or rather by smooth pieces of wood covering
the palm of the hand, and tied at the back with
strings. These are called planes.
The object of all these manipulations is the felting
together of the nap and the foundation. When this
is accomplished, and the roots of the fur have
actually struck into the hat-body, the workman is
immediately made aware of the fact, by the loosening
and coming away of the cotton wool, of which it has
been seen that a very small quantity was mixed with
the fur at the commencement of the process. This
cotton wool is incapable of felting, and, therefore,
affords a valuable indication to the workman, by
falling off when the other materials are felted, while
in the previous stage it was of use in giving substance
to the nap, and in effecting a saving in the quantity
of beaver employed. I'Vere the workman to continue
rolling and pressing too long, the hairs of fur would
pass completely through the hat-body and be found
on the inside; therefore, it is important to know when
to stop. Up to this point the napped hat-body still
remains aloose conical cap, without any resemblance
to a hat. But by pulling it and adjusting it with the
hands, it is now capable of being drawn over a
cylindrical block, on which it is tied with a cord.
After much rubbing and pressing, the conical top is
flattened into a crown, and the whole is adjusted to
the shape of the block, while the brim, which is at
first a puckered appendage, is also gradually worked
into shape. The hat is now gradually dried in a hot
room, and is afterwards made ready for dyeing, by
first raising the nap by means of a carding-comb,
and then cutting off the tips of the hairs so as
to make them all of one length. This shearing
requires a skilful hand, or the nap will be unequal
or in furrows. It is done at one cut of the shears
down the side of the hat, thus passing round and
round the hat many times. The hats are further
prepared for dyeing by being softened at a hot

bath, called a blockmy-lrezflla, and again drawn over
wooden blocks.
When a number of hats (generally 5 dozen, called
a suit) have been thus prepared, they are hung on pegs
within an iron cradle, and thus lowered, by means of a
crane, into the dye-
copper, Fig. 1128. ,/-,j'fi?3:"'~‘"“
Here they are im- //
mersed in a prepara- M
tion of sulphate of '
iron,verdigris,andlog-
wood, in water, form-
ing a strong black
dye. The cradle is al- I", L A; r
lowed to remain in I‘ flit—e}: q \ II
this dye, at a tem- -. \ mfmjfiv" P’,
perature of 180°, "‘ ‘
for about twenty
minutes, when it is
raised and left to
drain for half an
hour; this dipping
and draining are repeated 18 or 14 times, until a
bright glossy black has been obtained. The hats
are now removed from the cradle to the blocking-
kettle, the blocks are taken out, and the hats washed
in It separate vessels of Water, to remove any loose
dye stuff; they are then put on a rack to drain, and
lastly removed to the drying-room, which is heated to
160° or 170°, and where they remain on racks till the
drying is complete. They are then subjected to a few
finishing processes, the first of which is the picking
out of coarse hairs by means of tweezers. Notwith~
standing the care which is taken in sorting the down,
there are always scattered hairs, which become con-
spicuous at this stage of the manufacture for their
harsh and coarse appearance, and require to be
removed. This being completed, the crown is next
strengthened by inserting a piece of scaleboard, called
a tip, on its under side, and pasting a piece of linen
over it to keep it in place. A block is then put in,
and the general surface of the hat is dressed and im-
proved by means of warm and damp hair~brushes,
hot irons, and a plush cushion called a velours, or
veluse. If there are any refractory hairs which cannot
be made to lie smooth by these means, they are burnt
off by waving the hat rapidly through a large flame
produced by shavings. The hat is then delivered
over to women to be trimmed and bound, and to have
the lining and leather sewed in; and, lastly, a supe-
rior workman finishes off the whole by blocking and
setting up the hat in the most fashionable style.
One of the recent improvements in beaver hats
consists of a hat‘body of silk and a thin beaver pull-
over, as it is technically called. The method of
making the latter deserves notice on account of the
felting process by which it is accomplished, and
which may be taken likewise as a specimen of the
mode of production of the woollen hat-body used in
the ordinary beaver hat. The materials for the pull-
over being weighed out and bowed, and the sheet of
napping formed as before, the latter is at once made










Fig. 112s.
6 HAT.
into a conical cap, instead of .being simply folded to-
gether. For this purpose a triangular piece of brown
paper is damped, and placed upon the sheet of nap-
ping, which is folded over it, ‘and completely covers
and encloses it except at the
base. Fig. 1129 shows the pull-
over enclosing the paper; the
dark shaded portion represent-
ing the woollen hat-body lying
' upon it. Any superfluous por-
tions of the napping are removed,
and are bowed again, and used to
form the brim and thicken the parts requiring most
strength. The brown paper remains within, while the
cap is folded upin a damp cloth, worked about with the
hand, pressed, bent, rolled and unrolled many times,
whereby the fibres unite more closely. For a woollen
hat-body a metal plate or bason is put within the
cap instead of brown paper, the object being in each
case to keep the sides of the cap asunder, otherwise
they would felt together, and make a flat cone. On
account of this the process is called éasorzz'ng, even
when paper merely is employed. The cap, thus formed,
is twice as large as it will be when finished, for during
the felting it shrinks greatly, and becomes thicker
and more dense. The brown paper being removed,
it is taken to‘ the mahogany bench, sprinkled with
hot liquor, and worked about in a variety of ways. It
is then a perfect felted cap, and can be drawn over
the silken hat-body, of ‘which it forms the nap. The
blocking is then performed as before described, the
hat is dried and stifl’ened, and the after-processes are
proceeded with as in the ‘former instance.
The manufacture of silk hats is less interesting
than that of beaver, inasmuch as the felting process
is altogether absent. The operations are, in fact,
entirely different: no conical caps are made ; no hat-
maker’s battery, or blocking-kettle, or dye-copper, is
required. The hat-body is constructed on a block
which consists of five pieces, forming,
whenput‘together, as in Fig. 1130?, the
oval shape of a hat. This block, being
set up onv a bench, a piece of icalico is
folded round the side of the hat, and
the meeting edges are made fast by


Fig. 1129.


Fz'g 11250.
a solution of. shell-lac. The whole of this layer of
calico is then covered with cement, and another layer
is then added and treated precisely in the same man-
ner. The projecting edges at the top are then turned
down upon what is to form the crown, and over it
are cemented, in succession, three layers of calico,
the last layer being also cemented on the outside.
When these are all dry, a hat—body without a brim is
produced. To make the latter, an ova‘ piece of calico
is cemented to a piece of twilled material, the latter
being stronger and more absorbent of cement. The
centre of this oval is cut away to suit the size of the
hat, leaving a brim, which is secured to the hat by
cementing one loose edge to the inside, and the other
to the outside. A piece of calico saturated with
cement is also bound, and ironed round the hat, to
keep the brim firmly in its place: this is called a

band-r0665”. When quite dry, the proper width is
given to the brim by means of a rowzdz'ng-tmss, 01
gauge, with notches, Fig. 1131, into one .\ of which a knife is fitted, and in passing
round the brim cuts off the superfluous
portion. The hat-body is thus com-
pleted, and the method of covering it
is equally simple.
The material for covering silk hats is
a silk plush, woven like velvet in a loom with three
treadles, and having a velvet nap or shag on one side.
This fabric is manufactured in Spitalfields, and at
Coventry and'Banbury, but the chief supply is imported
from Lyons‘. The plush is received in pieces of 2001'.
30 yards long, and 26 inches wide, and great nicety is
required in cutting it out, that none of the material
may be wasted. It is cut into three distinct forms,
namely, a circular piece for the crown of the hat, a
rhomboidal piece for the side, and a long strip for the
brim, rather wider than is sufficient to cover both its
sides, and sewn together at the ends. The crown and
side piece are sown together, so as to form a bag or
cover to the hat, having a diagonal opening at the
side. To put this on smoothly and well is. a work of
some dexterity. The calico hat-body, which is covered
in every part with a layer of dry shell-lac varnish, is-
now rubbed with sand-paper to remove roughnesses.
The strip for the brim is then fitted on, covering both
surfaces‘, and being made to adhere by the application
of a wet sponge, and then a hot iron, which act on
the cement below, and make it hold fast the plush
which is pressed down upon it. It is necessary to have
both hands at liberty in the nice adjustment of the
plush to its foundation, therefore a brass wire, at
tached to a rope stirrup, is made to embrace the hat
just at the angle formed by the brim and the body;
and this wire enables the workman to gather up all
puckers in the upper cover of the brim, and cut away
the superfluous portion above the Wire. Fixing the
remainder by means of the sponge and iron, he next
adjusts the under surface of the brim, where the wire
is evidently not avail-
able, but a brass plate,
Fig. 1132, of a semi-
circular shape, let
into the work-bench,
answers a similar pur-
pose in keeping the hat steady, and leaving the
workman the free use of his hands. The super-
fluous portion of the plush is in this case not out
off, but turned up within the hat and secured to it.
The plush-bag, or cover, has now to be drawn over
the crown and sides of the hat, and adjusted so as to
form a perfectly smooth surface. The diagonal line
formed by the union of the parts is entirely concealed
by the nap, but becomes visible in an old silk hat.
Any fulness or tendency to pucker is drawn down
into the band. _ Moisture and heat are applied as
before to make the union of the parts perfect,
and the surface smooth. A wire carding-comb is
also drawn over the plush, which is further smoothed
and made glossy by the application of a dummy


Fig. 1132.


HAT. 7
of box-wood shaped like an iron, and of a velvet
cushion.
The trimming and lining of these hats is performed
by women, after which they are returned to the
workshop to be tipped off, or shaped. A curl is given
to the brim by the thumb and finger, after the part
has been sufficiently softened by the sponge and iron.
By holding the hat before a stove, the whole surface
becomes soft enough to be moulded into any required
shape: a hat-screw, then introduced, elongates the
hat, while the shaping of the sides and brim can be
easily performed by the hands. Imperfections in the
nap are then removed by a steel picker, and the hat
is polished and wrapped in paper for sale. So exten-
sive is this manufacture at the present time, that for
every beaver hat, it is calculated that 1,000 silk hats
are fabricated.
We have not the means of furnishing the statistics
of this important branch of industry at the present
time. Some years ago England produced about
250,000 dozen of silk hats annually, of which more
than half were fabricated in London. The annual
value of the hat-manufacture, including beaver, silk,
and wool-felts, is estimated at 3,000,000l. sterling.
Many thousand dozens are exported, chiefly to the
colonies. The beaver hat trade employs more sub-
sidiary trades than the silk, on account of the prepa—
ration of fur, the making of long bows for the bowing
process, 860.: the workmen also require a longer appren-
ticeship to learn the former than the latter trade.
Our notice of the hat-manufacture would not be
complete without the mention of straw hats, which
did not begin to form an article of British trade until
late in the last century, although they were brought
to great perfection in Italy more than two centuries
ago. The importation of foreign goods having been
interfered with by war, our own manufacture of this
article rose into importance, and improvements in
bleaching, plaiting, and finishing, as well as in the
cultivation of indigenous grasses, were much encou-
raged by premiums from the Society of Arts. The
straw of Tuscany, however, maintained its repute,
and was plaited by our workpeople after the Italian
method. This consists in first carefully sorting the
straws as to colour and thickness, then selecting a
certain number, frequently thirteen, and tying them
together at one end. They are then divided into two
portions, six straws being turned towards the left
side, and seven to the right, so that the two portions
of straw are at right angles to each other. The
seventh, or outermost straw, on the right hand, is
then turned down by the finger and thumb, and
brought under two straws, over two, and under two.
There are now seven straws on the left, and six on the
right, therefore the outermost of the left hand straws
is now to be turned down, and passed under two,
over two, and under two again. The plaiting is con-
tinued in this way, alternately doubling and plaiting
the outermost seventh straw from side to side, until
it is used up. Another straw is then put in under
the short end, in the middle of the plait, and by the
crossing of the other straws over and under it, the

fastening of it becomes secure. This kind of plait,
shown in Fig. 1133, of about double the real size, is
formed in pieces of great length, which are adjusted
according to the Italian method, in spiral coils, to
form large flats, as they are called, the edges being
adroitly knitted together in the manner shown in
Fig. 113%, which gives the plait, for the sake of dis-


‘ i
- as centers


Fzg. 1 13.3.
tinctness, nearly four times larger than the real plait.
The dotted lines show how far the angular folds or
eyes of one piece are inserted into those of the ad-
joining piece. The thread which is run straight along
in the interior is entirely concealed, and the join can
only be detected by the slightly increased thickness
of the plait. The best plaiters use the second finger
with their thumb at their work, thus leaving the first
finger free to turn the straws.
All the processes connected with the straw-hat
manufacture, especially in warm climates, can be best
performed in the spring, at which season there is also
the largest demand for bats and bonnets of this mate-
rial. The plaiting is much more perfectly executed
in that temperate season than when the heat of sum-
mer has soiled, or the cold of winter has benumbed
the fingers of the workpeople. No bleaching can
effectually remove the tarnish communicated by warm
and soiled hands, nor the tinge given in smoky rooms
in cold weather. The large flats, above alluded to,
are received in cases of from 1 to 20 dozen, varying
in degrees of fineness. Names are given to the flats
according to the districts which produced them.
Florence is the principal market for the Italian hats.
British straw plaiting chiefly prevails in the
counties of Bedford, Hertford, and Buckingham, but
is carried on also in Essex, Suffolk, and other counties.
When the straw is of British growth the process is
as follows. The whitest and most regular straws are
selected, and cut into equal lengths, then bleached
by exposure to fumes of burning sulphur, and split
lengthwise into several segments. To effect this a
wire having four, six, or eight sharp edges is passed
up the middle of the straw. The slips thus obtained
are softened in water, and can then be plaited with
great rapidity. The plait is passed between wooden
rollers to make it flat and hard. The hat is formed
8 HEARTH—HEAT.
from it by winding the plait on a wooden block of
the required shape in a spiral direction, leaving a
little. overlap, which is sewed to the part beneath.
The seams are afterwards pressed down with a hot
iron.
This domestic and healthful employment affords
subsistence to a great number of persons‘, and use-
fully employs women and children whose labours
could not otherwise be turned to so good an account.
At the present time there are probably from forty to
fifty thousand persons engaged in the manufacture.
There are many varieties of plait in general use,
known as whole Dunstable, split straw, patent Dun-
stable, or double seven, Devonshire, Luton plait,
Bedforcl Leghorn, Italian plait, 850. There are also
endless fancy plaits. Hats of Brazilian grass, bonnets
of plaited whalebone shavings, and other curiosities
of manufacture, also appeal to the love of novelty of
purchasers. ~
HEALDS.—See Wnnvrne.
‘HEARTH—The flat or hollow space in a smelting
furnace, upon which the ore and fluxes are submitted
to the influence of flame. See GorPnn—Inon, &c.
HEAT—In its ordinary sense the term heat is
used to denote a quality otherwise called high temper-
ature, the reverse'of cold or low temperature. Ina
scientific sense the term heat or calorie is used to
denote that substance or action which by its greater
or less abundance or intensity in matter produces
effects which are also expressed by the terms high or
low temperature.
In all inquiries into the effects of heat, it is neces-
sary to attend to the following rules. respecting the
application of the term temperature :——I. If a body
subject to no pressure, or to a constant pressure, have
at two different times the same bulk, it is said on
both occasions to have the same temperature.
II. Two ‘bodies are said to have the same temper-
ature if, being kept in contact, the temperature of
either remains unaltered by the action of the other.
III. When bodies of different temperatures are in
contact, the temperature of the hotter body decreases
and that of the colder increases, till they become
equal.
TV. If the bodies be equal in mass or in weight, and
of the same substance, the increase of temperature in
one will be equal to its decrease in the other.
Hence it will be seen that differences of temper-
ature are’measurable and comparable with each other,
quite independently of change of bulk; that is,
without using the latter as a measure of temperature,
but only as a test by which change of temperature is
detected. In this way it has been discovered that
the same increment (not equal increments, as from
40° to 50°, and from 50° to 60°) of temperature
causes all masses of the same substance to expand in
the same ratio to their whole former bulk; but this
is _by no means the case with different substances, as
is obvious by looking at a common thermometer, an
instrument for measuring changes in the bulk of a
mass of liquid contained in a glass vessel of such a
form, that changes, very small compared with the

whole bulk of the liquid, may cause its surface to
rise and fall through a considerable space. Now,
this could not be done if the glass and the measiu'ing
scale, in undergoing the same changes of temperature
as the liquid, experienced also the same change of
bulk; for, if such were the case, the liquid surface
would always remain opposite the same degree on the
scale. The value of this simple instrument, therefore,
depends on the fact—that liquids are more expansible
than solids.
But it will further be seen that the ratio of the
change of bulk to the wlzole bulk is difl’erent for every
different substance, when the change of temperature
is the same in all. It is necessary, however, to guard
against a very common error respecting the relation
between temperatures and the nnmlers by which they
are represented; namely, the degrees of the thermo-
meter.
Although the .clg'firenees of temperatures are known
and comparable quantities, yet their ratios are not so.
We can compare them by addition and subtraction,
but not by multiplication or division. We cannot
say, “ This temperature is so many times t/zat,”
because we do not know the real zero of temperature;
that is, we do not ‘know whatv is the smallest bulk
into which a given body is capable of being condensed
by cold. We cannot, therefore, say, “ Tit-is body
exceeds its minimum bulk by’twice as much as that
body exceeds its minimum bulk; ” or, in other words,
“ This body is twice as ‘hot as that; ” for although _
the temperature of one body may be 80°, and that of
another 40°,’ these numbers are only reckoned from
an arbitrary zero or starting-point, adopted because
the real zero is unknown. But although we cannot
say that A has twice the temperature of B, we can
say that the temperature of A exceeds that of B by
twice as much as the temperature of o exceeds that
of n.
The first question, then, regarding the relation of
expansion to temperature, is —-“ Do equal differences
of temperature cause the bulk of a body to vary by
equal differences P” This question had to be settled
before it could be known whether the common ther-
mometer (the scale of which is divided into equal
parts) measured diflerences of temperature correctly.
For "this purpose, Dr. Brooke Taylor heated two
equal weights of water, one to 200° and the other to
100°, and on mingling them together, he found them
to indicate exactly 150° ; thereby showing that equal
differences of temperature cause equal differences in
the expansion of mercury; or rather in the excess of
its expansion over that of glass, which is clearly all
that the thermometer can measure. More accurate
experiments, however, have shown that this rule does
not ezvaetlg apply to any solid ,or liquid, but only to
gases. When equal masses of the same liquid, at
difl’erent temperatures, are mixed, their combined
bulk becomes a very little diminished. Liquids,
therefore, instead of expanding by equal increments
of space for equal increments of temperature, expand
faster as the temperature increases egnalalg ,- and it
appears that the correctness of the mercurial thermo—
HEAT. 0
meter observed by Dr. Brooke Taylor was thev result
of a fortunate coincidence, by which the expansion
of the glass, which is very small compared with that
of the mercury, exactly compensated the‘ increasing
rate of the latter. This, however, would not be the
case with thermometers constructed with other liquids,
for their rates of expansion increase more rapidly
than that of mercury. Hence spirit thermometers
cannot be depended on for temperatures above the
atmospheric range (or above 100°).
The rate of expansion in solids is also found to
increase as they become hotter; but it is more
equable than that of liquids. Instruments. for mea-
suring the expansion of solids are called pg/nonzez‘ens
to distinguish them from thermometers, which measure
the expansion of liquids and airs. The measurement
of solid expansion is, however, by far the more
delicate and dilficult, not only from its smaller amount,
but because we cannot measure at once the whole
cubical increase or expansion, but only the increase of
one linear dimension, that is, the elonguz‘ion or clilum-
zfion. As solids do not in general alter their form by
change of temperature, all the dimensions increase
and ‘decrease in the same ratio. The only known
exceptions to this are afforded by crystals.
The first effect of heat onsolids is expansion. If,
however, the heat be more energetic, the solid is
resolved into ‘a liquid. The liquefaction of some
solids is gradual; they pass through various de—
grees of softness ; but in many, perhaps in most cases,
there is no intermediate state between perfect solidity
and perfect fluidity: the solid is heated up to a
certain point, at which it remains solid; but a very
slight increase of heat is then suificient to liquefy a
portion of it. Now, it is an important fact that the
same substance always passes from the solid into the
liquid state at precisely the same temperature, and
this is called its melting point if it be above, or fi'eez-‘
ing point if below the medium atmospheric tempera-
ture. Thus the melting point of ice, or the freezing
point of water, is 32° on the scale of Fahrenheit used
in this country; but it is made the zero or 0° of the
continental scales. The freezing point of mercury is
about 70° Fahr. lower than 32°, and is therefore
called ~ 88° (minus 38°,) or 38° below zero, a degree
of cold which in England can only be produced, arti-
ficially. By the same means almost, every other body
that is liquid at common temperatures has been
rendered solid. On the other hand, there are very
few solids which have not been melted by ‘artificial
heat, or by that of the sun concentrated; and each
one has its fixed and unalterable melting point.
Thus, tin melts at 442°, lead at 594°, zinc at 773°,
antimony at 812°, and so on.
But there are important circumstances to be noticed
in the liquefaction of these bodies. It is evident that
if a quantity of ice, at the temperature of zero, or 0°,
be taken into a room whose temperature is 60°, the
ice will begin to melt; and a thermometer placed in
it, which at first indicated zero, will rise and soon
reach 32° ; but at this point it will remain stationary
until the ice has entirely passed into the liquid form.

Even if the vessel containing the ice be placed upon
a fire, the mercury in the thermometer will not rise
above 32° so long as any ice remains in the vessel.
Now, it is obvious that, during this time, a quantity
of heat must be constantly entering the vessel with-
out rendering its contents hotter; for so long as this
influx of heat is engaged in liquefying the ice, it
produces no effect upon its temperature. Thus we
see that increase of temperature is only one of the
modes in which heat or caloric acts, and that when a
portion of heat is producing the effect of fluidity, it
cannot be at the same time producing the effect of
temperature. The effect here described for ice applies
equally to other solids. Hence we see that, during
the process of liquefaction, a large quantity of heat
disappears, or is absorbed, so as to be no longer
sensible to the touch or to the thermometer. The
heat thus lost is sometimes called the neat‘ offluiclily,
or lui‘enl lzeui, in contradistinction to the heat of
temperature.
Another general effect of heat is the conversion of
liquids, by an enormous expansion, into airs, gases,
or vapours, as when water by boiling becomes steam.
This effect is attended by the same important circum-
Stance as in liquefaction, namely, the, absorption or
apparent loss of a large quantity of heat, which,
however, reappears when the vapour is condensed
again into the liquid form. A vessel of boiling water
exposed to the atmospheric pressure of 30 inches
maintains the constant temperature of 212°, and the
most violent heat is insufficient to raise it above this
point. The heat thus expended in vaporizing water
without raising its temperature is sutficient to raise
it no less than 970° if it were not vaporized; or, in
other words, the latent heat of steam is nearly
1,000°.
Different bodies manifest different capacities for
heat; that is, if two equal masses or weights, of the
same temperature, receive the same amount of heat,
they will not become equally hot, even although they
do not change their state. For example, if a pound
of mercury at 160° be mingled with a pound of water
at 40°, the resulting temperature will not be the
160;_4“‘O=100°; it will be only
45°; so that the 115° lost by the mercury heats
the water only 5°. On reversing the experiment,
and mingling a pound of water at 160° with a pound
of mercury at 40°, the result will indicate 155°;
so that the 5° lost by the water raises the mercury
115°.
Different bodies, therefore, have various degrees of
susceptibility to heat. To produce a certain change
of temperature requires a greater supply of heat in
some bodies than in others. Numbers proportional
to the quantities of heat necessary to produce the
same change of temperature in equal weir/his of diffe-
rent bodies are called the specific beats of these bodies,
or their capacities for heat. Thus, water is said to
have thirty times more cupacilyfor lieui than mercury.
There are three methods by which heat is diffused,
namely, by concluciion, by convection, and by radiation.

arithmetical mean, or
10
HEAT.
Bodies that are kept in contact will (if of different
temperatures) gradually change till they acquire the
same temperature; that is, their shares of heat of
temperaturerwill become proportional to their capa-
cities, and’ each body. will have the same temperature
throughout‘ its mass. But this diffusion does not
take place instantaneously, or there would be no such
thing as difi'erence of: temperature. The rapidity with
which heat. travels varies in different substances.
For example, if we place a silver spoon and awooden
one in boiling‘ water, the handle of the former will
become too-hot to be held before that of the wooden
one is sensibly warm. We see, then, that silver is a
good conductor, and wood a bad conductor of heat.
Different substances conduct heat at different rates.
If we call the conducting power of gold 1,000, silver
will be 9'13; copper 898, platinum 381, iron 37d,
tin 303, lead? 179, marble 23, porcelain l2, clay 11.
On placing; one land upon a piece of fur or flamiel,
and the other. upon a- piece of metal, both of the same
temperature; (as they must be if left under the same
circumstances,) ‘and. both colder than the hand, we call
one warm and the other cold. This is an effect of
sensation merely. The metal, being a good conductor,
abstracts heat from the hand and gives the sensation
of cold; the: fiannell or fur, being a bad conductor,
not only takes away no heat, but allows it to accu-
mulate, andl hence the sensation of warmth. Precisely
the contrary-r effect will take place if both bodies are
warmer than the hand. The metal will feel hottest,
and will .evenl burn us, at a temperature at which the
cloth woul'di hardly seem warmer than in the former
case‘.
But in liquids there can be no change of tempera-
ture without‘ a displacement of particles. If heat be
applied to‘ arvessel of water, the particles near the
bottom of tli'ervessel being heated first and expanding,
become specifically lighter, and ascend; colder parti-
cles occupy their place and ascend in their turn, and
thus a current is established, the heated particles
rising up through the centre, and colder particles
descending at1 the sides, as shown by the direction of
the armwsim Fig. ‘Z82, (article EBULLITIoN.) This
is evidently a very different process from conduction.
The heat is; not conducted from particle to particle
without displacement, as in the case of a solid; but
each particl‘e;.as fast as it receives a fresh accession
of heat, starts off with it, and conveys it to a distance,
displacing other and colder particles infits progress.
This process: has received the appropriate name of
convection, and» its importance will be seen if we apply
heat to the- saag/‘acc off a liquid instead of to its base.
Water being-a bad conductor, we may boil it at the
surface, whilera lumpiof ice sunk to the bottom will
remain unmelted.
Gaseous bodies, however, from the great mobility
of their particles, are the most rapid conveyers,
although (and, indeed, because) they are the slowest
conductors of? heat. Any body hotter than the air
sets in motion an upward current of that fluid, which
may be easily» Seen rising from bodies that are much
heat-ed, and the particles which rise are immediately

replaced by the influx of other particles from every
side. The slightest difference of temperature is suffi-
cient to produce these effects, and hence the rapidity
with which the air reduces all bodies to its own
temperature. Abody colder than the air, such as a
lump of melting ice, produces an opposite action:
it cools the airin ‘contact with it, which, becoming
denser, descends in a continual stream, supplied by
an influx of. air from all sides to the ice, until the
whole is melted.
Actions of the same kind in the great scale of
nature give rise to all the varieties of wind, by which
the whole mass of the atmosphere is kept in motion,
and its temperature so far equalized as to mitigate
the extremes of climate, and render both the equator
and the polar regions habitable. Such effects as
these could not take place if the great ocean of air
were heated (as at first sight it may appear to be)
from above. The atmosphere receives scarcely any
of its warmth directly from the sun’s rays, but is
heated almost entirely by the ground on which it
rests, and is, therefore, in the condition of the water
in a boiler, where the heat is applied from below.
But it is different with the liquid masses of our
globe. The heat is applied to them at their surface,-
and is therefore not difiused by convection. It creeps
slowly downwards by conduction, so that the tempera-
ture of all deep waters is found to diminish downwards.
In the absence of the sun, however, the process of
cooling goes on by convection; the surface waters
being cooled first, become denser, and therefore sink,
while new portions are brought to the surface, where
they are cooled and sink in their turn; by which cir-
culation the whole would very soon be reduced to
the freezing point, were it not that the wisdom of the
Creator has ordained that the general law of rare-
faction by heat and condensation by cold shall, between
certain limiting temperatures, be reversed. Thus
water contracts by abstraction of beat down to about
39%’, when it has attained its point of greatest con-
densation by cold; from’this point to 32°, its freezing
point, it expands by the application of cold. Hence
the operation of this exceptional law gives rise (in
water below 39%’) to a species of convection exactly
the reverse of that in other fluids, namely, a convection
of heat more readily downwards than upwards. Thus,
above the temperature of 39?’ masses of water are
more easily cooled than heated; and below 39%o they
are more easily warmed than cooled.
The third method by which heat is diffused is by
radiation, as when we stand at a distance from the
fire, and experience its warmth. The heat is not, in
this case, brought to us by any current of air, for that
must set in towards, and not from, the fire; and
besides, heated currents tend constantly to ascend.
Nor can it depend on the conducting power of the
air, for that is very slow indeed, and we experience
the heat of the fire instantaneously. From these and
various other reasons, it is evident, that a substantial
medium, path or passage is not necessary for the
propagation of 'heat.
If a red-hot cannon-ball be suspended in the air,
HEAT.
11
rays of heat will be emitted from it as a centre, in
radial lines, which move with the velocity of light,
and, like the luminous rays, may be reflected, absorbed,
refracted, transmitted, &c., by encountering certain
surfaces; and these rays may be reflected or trans-
mitted without disturbing the temperature of the
reflecting or transmitting bodies ; but if the calorific
rays be absorbed (that is, if they are stopped, and
wholly or partly cease to exist as rays), an immediate
increase in the temperature of the absorbing body is
the result. This transmission must not be confounded
with conduction of heat. The latter is always ,a slow-
proccss, while the transmission of radiant heat, or
calorific rays, is instantaneous. It is the peculiar
property of these rays, that they do not heat bodies
through which they pass,v as conducted heat must do.
The worst conductors of heat (air and gases) are the
best transmitters of these rays, while the best con-
ductors (metals) totally stop the progress of the
rays.
The intensity of radiant heat diminishes in the
ratio that the squares of the distances from the
radiating points increase; that is to say, the heating
effect of any hot body (such as the red-hot ball above
noticed) is nine. times less at three feet than at one;
sixteen times less at four feet; and twenty-five times
less at five feet. Now, as this law applies to all
influences that spread from a centre, such as gravita—
tion, light, heat, electrical forces, magnetism, sound,
and in fact all cenlraljorces when not weakened by
any resistance, or opposing force, it is desirable to
impress the law fully on the reader's attention by
giving a reason for it. Suppose a board two feet
square, Fig. 1135, to be held with its centre exactly


Fig.1135.
two yards from a candle, and another board one foot
square to be held parallel with the first board, and
exactly half-way between it and the candle, it is
evident that this will exactly intercept the whole of
the light that would have fallen on the first board,
and no more. But its area is only one-fourth of the
first board. Hence we see that the same quantity of
light which at one yard from its source covers one
square foot, will, at two yards from its source, be
spread over four square feet, and consequently be
four times less intense. So, also, a board one foot
square will intercept exactly all the light from another
board that is l/zree feet square, if the latter be three
times as far from the candle; so that any portion of
the latter board would receive only one-nintb as much
light as falls on an equal space of the nearest board.
Now, all this must- plainly apply not only to light,

but to any force that proceeds from a centre in straight
lines or rays, and consequently to radiant heat.
All bodies, when raised to an equal temperature,
do not radiate equal quantities of heat in equal times.
It is, however, remarkable that the rate at which a
body cools is influenced by the state of its surface
morethan by the nature of the material of which it
is composed. A vessel covered ‘with lamp-black and
filled with hot-water will cool down to, the tempera-
ture of the ‘surrounding air almost twice as quickly
as the same vessel with a bright polished surface.
If we call the radiating power of lamp-black 100, that
of writing paper will be 98, sealing-wax 95, crown
glass 90, plumbago 7 5, tarnished lead 45, mercury
20, clean lead 19, polished iron 15, gold, silver,
copper, and tin, all polished, 12. It has been proved
that the same surfaces which radiate most quickly
also absorb rays of heat most quickly; and it is re-
markable that these two properties are exactly pro-
portional in all bodies, or, in other words, the same
numbers which express the relative radiant powers of
any list of‘ substances (as above) will also express
their relative absorbent powers.
By absorption we do not here mean the conversion
of sensible into latent heat; but the conversion of
radiant into conductible heat. Not all the radiant
heat, or rather the radiant effect, which enters a
body is immediately absorbed or converted into heat :
a portion continues its course through the body
without warming it; and though more and more is
absorbed at every step, yet if the body he not thick
enough to absorb all the rays, some of them will
emerge on the other side and continue their course
till, by the warming; of the various media through
which they have travelled, all their heating effect has
been expended and they cease to exist as rays. The
speed with which this is effected is enormously ferent in different media. Those in which it takes
place most slowly are called the most dz'alberrnanons ,-
but no medium, not even air, is perfectly diatherma-
nous, though a thickness of many miles of it absorbs
less radiant heat than a small fraction of an inch of
most solids. Hence the atmosphere is scarcely
warmed at all by the sun’s rays passing through it,
their effect ‘being produced on the ground or sea,
which in its turn warms the air, by convection, which
is a necessary process in the production of minds.
Not all the radiant effect which falls on the surface of
a new medium enters it; a portion is always reflected.
Radialz'ons or effects which are propagated in straight
lines only (such as light and radiant heat), are most
conveniently considered by dividing them into innu-
merable straight lines or rays; not that there is any
such division in nature, but to enable us, amidst
the extreme complexity of these phenomena, to con-
fine our attention to the simplest independent portion
of the effect. Every individual ray, whether of heat
or light, proceeds in a straight line until it meets
a reflecting surface, from which it rebounds in another
straight line, the direction of which is determined by
the law that the angle of incidence is equal to The
angle of reflexion, to which, however, in this case must
12 HEAT.
(on account of its generality) be added another con—
dition, viz. that the plane of reflea'ion, as it called,
I? (or that imaginary plane which
contains both the incident and
the reflected ray,) is pei'penclien-
lar to the reflecting surface at
the point of contact. Thus, let
a ray from A, Fig. 1136, fall on
a reflecting surface at B. We
must suppose a perpendicular to
this surface erected at the point
1), then the same plane I? 1?, which contains both the in-
cident ray and the perpendicular, will also contain the
reflected ray B 0, both rays making equal angles with
this perpendicular B 1), but on opposite sides of it.
When the surface is curved, a perpendicular or normal
(as it is then called) can equally be erected at any point
of it; for it must be remembered that each mathema-
tical point of such surface acts precisely as a tangent
plane, that is, as a plane touching the curved surface
at that point would act. Thence it happens, that
certain regularly curved reflecting surfaces, called
mirrors or speenla, possess some remarkable proper-
ties. For example, if a mirror have the form of a
paraboloial, any number of rays radiating from the
point called its foens will be reflected into parallel
directions, and any number of parallel rays coming to
such a mirror are all reflected so as to meet in its
focus.
In Fig. 1137, two such mirrors, A and B, are shown.




Fig. 113.".
They are made of metal, and highly polished, because
we have seen that this kind of surface is the worst
radiator, and therefore absorbs the least proportion
of the rays that fall on it, and consequently must
reflect the greatest quantity. If these mirrors be
truly centered, that is, placed so that their axes may
be exactly in the same straight line, and if a hot body
be placed at c, in the focus of the mirror A, all the
rays which it sends to that mirror will be reflected
into parallel lines, and so reaching the other mirror B,
will be reflected by it, and all brought to meet in its
focus D, where a thermometer will be affected more
than at any other spot, even though such other spot
be much nearer the hot body 0. Moreover, if a screen
be placed either between 0 and A, or between B and
D, the effect on the thermometer instantly ceases.
To render this experiment more striking, a red-hot
iron ball is sometimes placed in the focus of one mir-
ror, and some combustible, such as gunpowder, phos-
phorus, paper, 860., in the focus of the other. These
bodies will be burnt, although their distances from
the ball 0 may be 10 or 15 feet.
If, instead of a heated ball, we place in the focus
of the mirror A a ball of ice, a thermometer in the

focus of the mirror B will be observed to fall. “Then
this experiment was first performed, it was supposed
to arise from the radiation of cold. This, however,
was a mistake; since no principle of cold, considered
as a positive quality, can be admitted, cold being
merely a sensation arising from the abstraction or
diminution of heat ; as darkness results from the
absence of light, and silence from the absence of
sonorous vibrations. In this experiment the thermo-
meter sinks, because it radiates heat to the ball of ice.
Hence we learn, that even a body at the ordinary
temperature must be constantly radiating heat ; and,
of course, can only preserve its temperature by the
counter-radiation it receives from other bodies. When
two bodies are placed in the foci of the opposite mir-
rors, they are, as it were, isolated or cut off from any
other source of heat, so that any heating effect ob-
served in one must be derived from the other. The
thermometer, therefore, in the last experiment, has
a large proportion of its supply. diminished much
below its usual ,intensity, so that (its radiation re-
maining unaltered) its temperature must sink lower.
than usual.
These generalizations enable us to explain a still
more remarkable instance of the apparent focalization
of cold. If one of the parabolic mirrors be placed so
that its axis1 may point to the sun, as the rays
coming from a body at so vast a distance are physi~
cally parallel, they will all be reflected to the focus of
the mirror, so that it will act as a powerful burning
mirror. But if the mirror be turned so as to face
a portion of clear blue sky (the bluer and the nearer
the zenith the better), its focuswill become a focus
of cold, and a delicate thermometer placed therein
will sink, in clear weather, some degrees even in the
day time, and as much as 17° at night.
Now, in order to understand this effect, it must be
remembered that the thermometer is constantly ra-
diating heat in all directions, and also. receiving from
surrounding bodies, in ordinary circumstances, just
as much heat as it radiates. But in this experiment
it receives less, because its usual supply from below
is cut off by the mirror. But it may be asked, “ Will
nothing but a mirror serve this purpose?” Any
other body would radiate from its own surface as
much heat as it intercepts from other bodies; but
a polished metallic surface, being the worst of radia-
tors, supplies less heat than it intercepts. It must
also have the form of amirror, the focus of which
must coincide with the place of the thermometer, be-
cause, if it had any other form, it would reflect to the
‘thermometer some of the rays which it received from
other bodies; but, because it is a paraboloid, it can-
not reflect to its focus any rays except those that
come in a certain direction, namely, parallel with its
axis. Now, in that direction no rays come, for there
is no body either to reflect or to radiate them. If a
cloud, indeed, pass before the axis of the mirror, the
thermometer rises to its usual height.

(1) The axis of a paraboloid, or of any mirror, is an imaginary
line drawn from its centre through its focus, and prolonged inde-
finitely.
HEAT—HELIOSTAT—HEMP.
13
‘The following are some of the miscellaneous effects
of heat :—--
deg.
—-135 Greatest artificial cold yet produced (Faraday).
(Alcohol, ether, and sulphuret of carbon did not
freeze.)
Carbonic acid (liquefied by pressure) freezes.
/ Estimated temperature above the atmosphere (Svan-
berg and Fourier).
55 Lowest atmospheric temperature observed by Parry.
(Ross states it‘ at -60°, and Back at ---71°.)
—- 38-6 MERCURY FREEZES.
— 23 Greatest cold observed in Britain (Glasgow, 1780).
Proof spirit (half alcohol and half water) freezes.
Temperature observed at Greenwich in 1838.
Nitrous acid boils under the common atmospheric
pressure.
3 Temperature observed at Greenwich, 1820.
4 Saturated brine freezes.
7 Spirits containing 25 per cent. of alcohol freeze.
4 Oil of turpentine freezes.—Sulphurous acid boils
(common pressure).
20 Strong wines freeze.
28'5 Sea—water freezes.——30° Milk freezes.
32 WATER FREEZES, or Ion llIIELTS.
36 Olive oil freezes.
39'8 Water is condensed into its smallest bulk.
50 Oil of aniseed freezes—Mean temperature of
England. 7
52 Mean temperature of London. —~Muriatic ether
boils.
70 Nitric ether boils under the common atmospheric
pressure.
81'5 Mean temperature at the Equator in America (83°
in Africa).
95 Highest atmospheric temperature observed at
Greenwich, 1808; 915, in 1825 ; 902, in 1846.
97 Pure ether boils under the common atmospheric
pressure.
98 Human vital-heat, or blood-heat.
( 108 Phosphorus melts (and inflames in atmospheric
air.)
117 '3 Greatest atmospheric heat observed by Burckhardt
in Egypt—Ditto, by Humboldt, in Guiana, 860.
149 Wax melts (or becomes transparent).
1735 Pure alcohol boils under the common atmospheric
pressure.
The most fusible alloy of tin, bismuth, and lead,
melts.
WATER norns under the common atmospheric
pressure.
Saturated brine boils.—218° Sulphur melts.
Heat obtained from the solar rays, by Saussure;
(237°, by Robison).
Saturated ley of potash boils under the common
pressure.
Oil of turpentine boils—347°, Camphor melts, and
boils at 399°.
Sulphur re-solidifies.—442°, Tin melts.
Bismuth melts.
Sulphur melts a second time.
Phosphorus boils.
Sulphur boils (under common pressure).
Lead melts.
Linseed oil boils (under common pressure).
Strongest liquid sulphuric acid boils (under com—
mon pressure).
661 ll/IERCURY BOILS under the common atmospheric
\ pressure.
735 Zinc falls to powder, andat 773° melts.
810 Antimony melts. (Red-heat visible in the dark.)
980 Red-heat just visible in day-light.
Measured by the
Spirit Thermometer.
7
— 4
0
p-l
201
Measured by the Mercurial Thermometer.
212

225
221
280
312
430
476
482
554
570
594
600
620
ti
>.§
.Q s .
a: 2 1,140 Heat of a common fire.—l,500°, Orangaheat.
in,“ 1,869 Brass melts.--l,873°, Silver melts (Yellow-heat.)
2 2‘: 1,996 Copper melts—2,016", Gold melts.
72 E 2, 786 Cast Iron melts (White-heat).
g 3,280 Greatest furnace heat measured by Daniell.
(Wrought Iron and Platinum did not melt.)
Flame of the oxy-hydrogen blowpipe, Platinum melts.
Galvanic current through air.
Not yet I
Measured‘ l Solar rays condensed by mirrors .... .. Gold bolls.

We see by the instructive experiment mentioned at
the bottom of p. 12, that every substance on the earth,
however low its temperature, is constantly radiating its
heat in all directions equally, and is also receiving heat
in every direction except from the regions of space, or
what we call the blue sky. After sunset, the supply of
heat from the sun is withdrawn, but radiation still con-
tinues; and if there be no clouds to reflect back the
heat, the temperature of the earth’s surfacesoon sinks
below that of the which rests upon it, and the
consequence is, a condensation of the moisture of the
air by the colder earth in the form of cleio. For the
further consideration of this part of our subject we
must refer to the article EVAPORATION.1
It appears from Mr. Joule’s Experiments, under-
taken with a view to determine the mechanical equi-
valent of heat,—-1st, that the quantity of heat produced
by the friction of bodies, whether solid or liquid, is
always proportional to the quantity of force expended;
and, 2d, that the quantity of heat capable of in-
creasing the temperature of a pound of water
(weighed in vacuo, and taken at between 55° and
60°) by 1° Fahr., requires for its evolution the ex-
penditure of .a mechanical force represented by the
fall of 772 lbs. through a space of 1 foot.
HEAVY SPAR, a term applied to native sulphate
of Barytes on account of its great weight, the sp. gr.
being from 4'41 to 467. See BAltIUM.
HECKLE. See FLAx.
HELIOSTAT, (from 1'7’7uos the sun, and the root
o'Ta to put or place,) an instrument, by means of
which a solar ray admitted into ~a darkened room may
be fixed in any desired position for optical experi-
ments. It consists of a plane metallic mirror, pro-
vided with a vertical and horizontal movement, and
of a clock, the index of which moves in a plane paral-
lel to that of the equinoctial. The extremity of the
index is connected with the hinder part of the mirror
by means of a long cylindrical rod adjusted perpendi-
cularly to the, plane of the mirror. -
HELIOTROPE, or BLOODSTONE. See Aex'rn.
HEMATINE, or Hmirxrnmn. See Loewoon.
HEMP. A plant supplying a valuable and efficient
‘material for cordage, and likewise every description
of canvas. The latter word appears to be a corrup-
tion of cannabis, the Latin name of the genus to
which hemp belongs. Cunnuois sulicu, or common
hemp, has been cultivated in the East from a remote
period, but not for its valuable fibres. The Orientals
prepare from it an intoxicating liquor called lung,
which serves both in India and Egypt as a substitute
for malt-liquor. Hemp is also supposed to be indi-
genous in Europe, for so long ago as the time of
Herodotus it was said to be growing wild in the
country of the Scythians, and also to be cultivated
for the fabrication of hempen cloth. In Russia and
Poland the cultivation of hemp is carefully attended
to at the present day, and the produce is of great
importance ina commercial point of view: it is also

(1) This article is abridged from the Editor’s “ Introduction to
the Study of Natural Philosophy,” second edit. 1851. Published
in Weale’s Rudimentary Series.
14-
HEMP.
cultivated in Italy, in the British isles, and elsewhere.
America fosters this plant, but not to an extent to
supersede importation. The hemp produced in Eng-
land and Ireland is of excellent quality, but its culti-
vation has not been found generally profitable, and
accordingly has been limited to a few districts.
The stem of this plant, as of flax, consists essen-
tially of a woody core, surrounded by a sheath of
fibrous matter, which is held together by a kind of
vegetable glue. The appearance and growth of the
two plants are, however, very dissimilar. Hemp be-
longs to the same natural tribe as the nettle, and
has the coarseness of growth which characterises its
relatives. It is an annual plant, some 5 or 6 feet high,
with a rough and strong stalk, 011 which large leaves
grow in pairs, on opposite footstalks, with two leaflets
at their base. Some of the plants are flower—bearing,
others fruit-bearing; the former being taller, more
slender, and having finer and more elastic fibres than
the latter. See Fig. 1138. It is impossible to distin-


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Fig.1138. HEMP.
guish this difference until the plants are nearly full
grown, or to calculate on the preponderance of one or
the other sort of hemp in the crop. The proportion of
each, however, is generally pretty equal. On a rich
moist soil hemp becomes coarse, but strong in the fibre ;
on a poor soil, it is slender and fine. If it be required
for cables, hawsers, and other heavy rigging, it can
scarcely have too rich a soil or too much manure; if
it be wanted for weaving purposes, it should be sown
broadcast on a poor soil. When sown and raked, or
harrowed, it requires great vigilance to preserve it
from birds, who have the utmost avidity for hemp
seed. It is a remarkable property of this crop that
it scarcely requires weeding; on the contrary, the
growing of hemp on a rank weedy soil is said effec-

tually to cleanse it, so completely does it occupy the
soil to the exclusion of all other vegetation.
In little more than three months the flower-bearing
hemp has arrived at maturity, its flower fades, the
farina falls, and the stem becomes yellowish. The
fruit-bearing plants are not perfected until three or
four weeks later, on which account there are fre-
quently two separate gatherings of the crop. These
are effected by pulling up the plants, cutting off the
leaves, flowers and roots, and tying up the stalks in
bundles. The next process is retting or rotting in
water for the purpose of dissolving the vegetable glue
which holds the fibres together. There are many
objections to this practice, which is slow, uncertain,
unwholesome and injurious to the fibre. “ Hemp,”
says Professor Solly, “though from its coarser fibre
less liable than flax to be injured by retting, is un-
questionably often greatly deteriorated by the fermen-
tation to which it is exposed; indeed in the old
methods of preparing hemp, it was never considered
to be retted enough until it was evidently injured.
In illustration of this rather strange statement, let
me refer you to Antill’s observations on dressing
hemp: he says, ‘ To know whether the hemp is rotted
enough, take a handful out of the middle row, and
try with both your hands to snap it asunder; if it
break easily it is rotted enough, but if it yet appear
pretty strong, it is not, and must lie longer till it
breaks with ease.’ ” Some improvements have been
made in the process of retting within the last few
years, more particularly as it applies to flax, where
warm water is used to expedite the operation; but
the larger proportion of hemp-growers continue on
the old methods to rot the stalks, either by letting
them he buried in snow, or exposed to the air and
dew, or steeped in the water of ponds, or in that of
running streams. The last named is mostly pro-
hibited, on account of the poisonous properties
attributed to the plant during putrefaction. The
mode of retting as practised in Livonia seems one of
the least obnoxious. Five or six basins about two
feet deep are dug at‘ different levels, where a fall of
clear water is to be had; these basins are divided by
slight banks made of clay, but communicate by
means of a small hole in each basin, which can be
plugged when required. The hemp is steeped in the
lowest basin for two or three days, then in the next.
higher, and so on up to the highest, fresh plants
being put in below as soon as there is room for them,
the water in the top basin being at the same time
renewed, and the holes unstopped so that a change of
water takes place at the same time in all the basins.
When fermentation has proceeded far enough, the
stalks are dried in the sun, or in ovens, or in warm
rooms. They are then broken at a hand-break, or by
mills, in the same way as flax, and the after processes
of scutching and heckling are likewise similar.
The hemp trade of Petersburg figures largely in the
commerce of that city. The hemp is brought to Peters-
burg from the interior beyondMoscow by water, and its
quality varies greatly, according to the country inwhich
it is produced. The great arrivals are in the spring
HEMP—HINGE.
is
and summer, and the work of sorting it into qualities
and making it up into bundles is performed by sworn
agents called brackers, and by binders appointed by
the government. To every bundle of hemp thus
assorted there is attached a ticket with the names of
the selector, binder and owner, and the date and year.
Every bundle has also a piece of lead affixed to it,
on which is stamped the selector’s name on one side,
and the sort of hemp and the time of selection on
the other. The external marks of good hemp are its
being of an equal green colour and free from spills;
but its quality is further tested by the strength of
the fibre, which should be fine, long, and thin. The
best quality is called clean hemp, or first; the next,
out-shot‘ hemp, or seconds; then comes half-clean hemp,
or thirds; and lastly, hemp coeZz'lZa. This last is
merely the part picked out in cleaning the other
sorts. Of the first three sorts there are shipped at
Petersburg every year about two million poods (sixty-
three poods make an English ton), and the greater
part of this is for the English and American markets.
In shipping hemp at Petersburg great care is
taken to preserve it from wet, which would cause it
to ferment afresh, and become totally spoiled. Every
vessel taking in either hemp or flax is therefore pro-
vided with mats for its preservation. The hemp
being light and bulky is forced into the hold of the
vessel by means of winches, and thus made to occupy
less room. The loading of a vessel is therefore rather
a slow affair. Commodious warehouses have been
built in Petersburg for the special purpose of housing
hemp, and in these the greatest order is observed.
A very fine quality of Russian hemp is obtained
from Riga, being brought down the river Dwina, from
the interior, about the middle of May. This fetches
a higher price than hemp from Petersburg. As a
general rule, the prices of Russian hemp are highest
in May, June, July, and the early part of August.
In the month of September bargains may be obtained,
many of the less opulent hemp-merchants being
willing to sell their remaining stock at some roubles
below the market price, in order that they may clear
all out, and return to their own country to make new
purchases for the ensuing year. '
The quantity of undressed hemp imported into the
United Kingdom in the twelve months ending May
1847, was 865,627 cwt. The quantity of dressed
hemp amounted to 1,230 cwt., of which 17lcwt. was
from British possessions, and all the rest from foreign
countries. In the parliamentry returns, there are
included, under the common title of rough hemp,
several other substances besides the true camzahz's
sat‘z'w ; for instance, several of those fibrous materials
which attracted so much notice at the Great Exhi-
bition, as Manilla hemp, Indian hemp, Jute, &c. The
first of the three just named is commonly called
Manilla white rope, and is obtained from the bark or
epidermis of a species of wild banana (Mush tezrtz'lz's),
which grows abundantly in the spice islands. Whole
forests of this kind of banana exist in Mindaneo, one
of the Philippines, and from it the natives fabricate
both cordage and cloth. Indian hemp, or Sunn,

(Crotolm'ea jzmcea,] is the fibre of a very different
plant from our hemp, grown in different parts of
Hindostan. Jute consists of the fibres of two plants,
of the genus Corehorus, extensively cultivated in
Bengal. It is mnch used in the great manufactures of
Dundee, for the coarse fabrics used for bagging, &c.
English hemp, though well qualified by its strength
and excellence for the manufacture of sailcloth and
cordage, is seldom used for that purpose; but is
principally made into the finer descriptions of hempen
cloth, some of which can scarcely be distinguished,
after they have become white by repeated use, from
Irish linen. Excellent hue/whack is made of it, for
towels and common tablecloths; and a coarse cloth of
great strength adapted for the shirting and sheeting
used by labouring men. There are also varieties of
superior quality and fineness, preferred by some gentle-
men on account of their great strength and Warmth,
and possessing, besides these advantages, that of im-
proving in colour the longer they are worn, whereas the
reverse is the case with every other kind of linen.
HIDE, see LEATHER.
HINGE,—~a joint of wrought-iron, cast-iron or
brass, on which doors, lids, gates, shutters, &c. are
made to swing, fold, open, or shut up. The usual
form is that of two leaves, each furnished with a pro-
jecting segment or segments of a hollow cylinder, which
fit together and admit of being united by a central
pin. In applying this joint, one leaf is screwed to the
door, and the other to the door-post, as is well known.
The chief varieties are noticed in Hebert’s Engineers’
and Mechanics’ Encyclopaedia, as consisting of “ crass-
gamets, made in the form of the letter T, for gates
and outhouse doors, from 6 to 36 inches long; and
a nearly similar kind made with long straps and
hooks to fix in the stiles, to enable the gates or doors
to be lifted off their hinges at pleasure. Those used
in common for the doors of apartments are termed
butts, of which there are many varieties; those used
for shutters are called haehy‘laps: similar hinges are
used for the joints of bedsteads, and very nearly the
same kind for Pembroke and other tables; another
sort called H and H__ hinges, from their resemblance
to these letters, are extensively employed for common
purposes. There are also many other sorts, dis~
tinguished by appellations that designate their uses,
and are too numerous to mention.” The chief manu-
factories are at Birmingham,Wolverhampton, Tipton,
and several parts of Staffordshire; the best wrought-
iron hinges are made in Lancashire, and the heavier
sort at Newcastle: there are also some excellent
makers in London.




64/; .
.4? @ @
a".
@ @
Fig. 1139 Fig 1140.
In Collinge’s hinge, as improved by Redmund, the
bearing pin consists of the conical stem h and the
conical top 2, Fig. 1M0, corresponding with the


1 61
HINGE.
bearing socket of the hinge, Fig. 1139. Over this is a
hollow capifixed tothe other limb of the hinge, the two
parts fitting accurately; this cavity is for the recep-
tioniof oil,and there is a small perforation to conduct
it. between‘ the two surfaces, which work with great
truth and freedom. This form is well adapted for
turnpike gates.
Mr. Redmund’s hinges are termed rising butts ; that
is, the hollow cylinder attached to the leaves, instead of
being divided at right angles to the axis or pin 6, Fig.
1142*, are divided by spiral, or rather helical lines, so
‘rm
l:





Fig. 1141.
thattvvhen the door is opened it is lifted up from the
floorr by the rubbing surfaces moving in a helical
line< upwards, so that although the door may shut
close:- down upon the carpet, it rises when opened to
a sufficient height to clear the carpet. Another
advantage of this kind of hinge is, that the weight of
the- door acting upon the inclined rubbing surfaces
causes it tor close of itself; but provision is also made
for‘ causing; the door to stand wide open when re-
quired : this is done by cutting away a portion of the
helical curves, so as to form two horizontal planes
which become opposed to each other when the door
is opened to] about an angle of 90°, or so as to form
a right angle with its positlon when shut. By this
arrangement, therefore, the door will close of itself
when not thrown open more than 50° or 60°, which
1s as-Imuch as is required for free passage, but it will
standl wide open if pushed as far as 90°. In this
position a slight pull will cause the horizontal plane
to slide off its support, and the door then returns by
its descent on the helix. By the introduction of a
smallispring the door may be made to shut to closely
when. opened only a very little way. Hinges supplied
with: more powerful springs are used for the swing
doors-‘of public oflices, &c., which are contrived so as
to open either way, and to return quickly to their
shut-to position.
In‘: connexion with spring hinges, we may mention
MraHebert’s contrivance for securing outside shutters
Fig. 1142.
Fig. 1143.
"Sm"!


whenthrown open. Fig. 114241, is the ordinary hinge
shut,- and Fig. 11415, the same open. A square hole
1s out out at a, and a semicircular piece of iron a {2

riveted into it; a portion of the iron being split so
as to form a spring, the extremity is turned upwards
to form a stop, as at c. On opening the hinge the flap
6 passes over the are, pressing on the spring, and
when arrived at the step c, it has passed the spring
and is completely open with the shutter fastened flat
against the wall. When it is required to close the
shutter, the spring, which is close to the Window, is
to be pressed down to allow the flap 6 to come back
over it; and when shut it appears as in Fig. 114141.
This contrivance is only wanted on the lower hinge;
it can be added for the additional cost of (Set. on a
pair of hinges, and supersedes the troublesome turn-
buckle, which fails to hold the shutter securely.
Whitechurch’s patent hinge is so contrived as to
allow doors, windows, &c. to be opened either to the
right or the left hand. Nettle- .
fold’s hinge for book cases con- 'i
sists of a brass plate a, Fig. 1M6, l
which is screwed to an upright l partition, projecting from a ,-. l j,
and cast therewith are the parts I a
b b, the extremities of which ,
are rounded off and perforated
to receive the centre pin, which I ‘
passes through them and the “ML
joint of the common butt hinge I _'
e, to the flaps of which are l screwed the doors at and e. It ' i ‘I
will be seen that the door e folds
back quite level with the bookshelves, and that the
door at folds close against e, so as to be paralle.
with it and quite out of the way, so that the books
close to the hinge can be taken out and put in
without first disturbing the adjacent books, which
is the case by the usual method of hanging doors
to libraries. Now it is obvious that when the door
cl is turned back the contrary way, both. doors are
shut and lie flush and close, and that the door e may
in like manner be folded over (l. Thus great conveni-
ence is afforded by a single hinge, instead of two
hinges, and the necessity for an additional hanging
style is avoided.
A number of patents have been taken out of late
years for improvements in the construction or manu-
facture of hinges. In Johnston’s patent (sealed July
1839) the eyes of the hinge are formed out of one
piece with the hinge plate, by forcing that portion of
the metal of which they are composed into dies so
shaped or formed as to turn over the metal into the
form of eyes. For example, two plates of malleable or
gas—.1
Fig. 114?. Fig. 1148. Fig. 1149.
ductile metal are first stamped out, as shown in Fig.
1147 : the projecting pieces or tongues are then forced
into and against the concavity of the die, Fig. 1148, by
which the tongues conforming to its curve become
bent flatwise in their whole length, or so as to bring













HINGE—BONE.
17
the ends over to their own surface or to that of the
plate to which they belong. See Fig. 114:9.
Wilkes’s patent (18410) is for manufacturing hinges
by casting the two sides or flaps, and hinge joint there-
to, at one time, on to a suitable axis. -
Horne’s patent (1840) is for an improved method
of preparing the strips or plates of iron for hinges, so
that the fibres of the metal shall be laid orplaced
crosswise of the, hinge 5 secondly, for an improvement
in making the joint, and for countersinking the screw-
holes by means of coned dies.
Redmund’s patent (1842) is for the construction
of each of the flaps and its knuckle—joint-piece of
rising hinges of one piece or casting 5 for a method of
casting gate or such like hinges in such a manner as
to obtain strength with lightness 5 also for a mode of
constructing spring hinges, the knuckle-j oints being
made hollow to receive a compound coiled spring‘
within a hollow axis. Instead of coiling a single
wire into a spring, as is usually done, the inventor
coils two, three or more wires side by side into a
spring, by which means he obtains powerful springs
in the same compass as that occupied by a spring of
like diameter of one coil of wire, and which would of
course be of much less strength. Figs. 1150, 1151,
and 1152 give difl'erent views of this hinge : j, is are
the two flaps; l a spring of
two wires placed within the
tube m, such tube being
the pin or axis of the
knuckle-j oints of the hinge;
rz is a pin or stem within
the spring, and fastened in
I the two ends of
r the caps of the
Fig‘ 1152- knuckle - joints.
The caps o 0, have each a two or more threaded female
screwformed therein to correspond with the springused,
and according as these caps are screwed up tightly so
will the pressure of the spring be regulated, there
being ratchet teeth to hold the caps, which allow them
to be turned each in one direction, but resist their turn-
ing back. The last part of the patent is for a door hinge,
which opens in either direction. Fig. 1153 shows the


7" 1L’




Fig. 1154.



plan of this hinge, and Fig. 11541 the axis for carrying
the door. On this axis is fixed the cam 12’, in which at 92
is a recess for the ‘reception of the pressing lever.
When the door is shut, q is a lever moving on an axis at
g’, and it carries a friction-roller 92 ,- a constant pres-
sure is kept up against this lever by the springs r r.-
Gollop’s patent (January 18%5) is for improve-
von 11.

ments in spring hinges and spring roller blinds.
Instead of cylindrical springs of wire, a coiled flat
bar or ribbon of steel is used. The arrangements
are ingenious, and admit of extensive application.
Wilkes’s patent (April 1845) is for forming the
knuckle-joints of hinges without flaps by casting or
otherwise separately; and then having combined
them on axes and placed them in suitable moulds, to
cause the flaps to be cast thereto.
Boydell’s patent (November 1845) is, 1, for a
mode of casting iron and brass hinges, the pivots or
axes of the knuckles of the hinges being of one piece
with one of the flaps of a hinge 5 2, for a mode of
casting brass hinges where separate pivots or axes
are applied after the flaps of a hinge are cast 5 3, for
a mode of making cast hinges, casting the vflaps of
hinges several at one time, and in one piece, and then
dividing them afterwards; 4‘, for a mode of anneal~
ing hinges.
HIRGINE, a peculiar fat obtained from the goat.
HONE, or Home SLATES, a term applied to
various slaty stones, which are used in straight slabs
for whetting or sharpening the edges of tools ‘after
they have been ground. on- revolving grindstones.
Mr. Knight, in his paper in the 50th volume of the
Transactions of the Society of Arts, has enumerated
the principal varieties. These are as follows :—
1. Norway ragstorze, the coarsest variety of the hone
slates. It is largely imported from Norway, in the
form of square prisms, from 9 to 12 inches long, and
1 to 2 inches in diameter. It gives a finer edge than the
sandstones, and is invery general use.- 2. C’fiarrztey
Forest stone is one of the best substitutes for the
Turkey oil-stone, and is used by joiners and others
for giving a fine edge to various tools, and also to
penknives. It is found in Charnwood Forest, near
Mount Sorrel, in Leicestershire.- The best variety
is said to come from the Whittle Hill quarry, the
other stones in the neighbourhood being more
pimzy, 2'. e. presenting hard places.
Sootolt stone, or snot/re storze, is used for polishing
marble and copper plates 5 but the harder varieties
are used as whetstones.
kept damp or even wet, to prevent them from
becoming hard. 4. Idwalt or Wetsk oz't storze is
similar to No. 2, but generally harder. It is ob-
tained from the vicinity of Llyn Idwall, in the
Snowdon district of North Wales, and is more gene-
rally used for small articles of cutlery than No. 2.
5. Deoorzslzz're oz't-storze, from the neighbourhood of Ta-
vistock, is described as an excellent, but little known,
variety,-_for sharpening all kinds of thin-edged broad
instruments, as plane-irons, chisels, &c. 6. 'Ozttler’s
green storze, fiom the Snowdon mountains of 7 North
Wales, is of so hard and close a texture as to be
applicable only to the purposes of cutlers and in-
strument makers, for giving the last edge to the
lancet and other delicate surgical instruments. 7.
German ‘Razor lzorze is known and esteemed through-
out Europe as the best Whetstone for the finer de-
scriptions of cutlery. It is almost exclusively used
for razors; for being very soft, it is cut by an instru-
c
3. Ayr stone,-
These stones are always‘
18
HONIl.
ment applied at an angle, instead of being laid down
flat as the razor is. vThis stone is obtained from the
slate mountains near Ratisbon, where it occurs in the
form of a yellow vein running into the blue slate,
sometimes not more than an inch in thickness, and
varying to 12, and in some places 18 inches; from
whence it is quarried, and sawed into thin slabs,
which are usually cemented into a similar slab of the
slate to serve as a support. That which is obtained
from the “old rock,” or lowest part of the vein, is
esteemed the best. 8. ‘Blue polishing stone is a dark
slate of uniform character, and not laminated in
appearance. It is used by jewellers, clockmakers,
and other workers in silver and metal, for polishing
off their work. It is cut into lengths of about 6
inches, and from 11— inch to 1 inch or more wide, and
then packed into small bundles containing from 6
to 16 in each, and secured by w'ithes of osier, in
which state it is imported for use. 9. Grey polishing
stone is similar in properties and uses to the blue, but
somewhat coarser in texture, and its colours are
paler. It is obtained from the same locality. 10.
WeZs/i clearing-stone is a soft variety of hone slate
cut in a circular form, and used by carriers for giving
a fine smooth edge to their broad straight-edged
knives used for dressing leather. 11. Peruvian none
has been recently introduced as a Whetstone, and is
said to come from South America. It cuts freely
with oil or with water, and is suitable for sharpening
large tools that do not require a very fine edge. 12.
Arkansas stone, from North America, is of unequal
texture, and cuts slowly. 13. Bohemian stones are
imported from Germany, and are used by jewellers in
the same way as Nos. 8 and 9, for polishing small
work, such as the settings around gems. They out
well, and keep a good point for small work.
In addition to the above, we may here notice the
Turkey oil-stone, although, from the absence of lamellar
or schistose structure, it can scarcely be considered
as a hone slate. Mr. Holtzapfi'el remarks, that “as
a Whetstone it surpasses every other known substance,
and- possesses in an eminent degree the property of
abrading the hardest steel, and is at the same time
of so compact and close a nature as to resist the
pressure necessary for sharpening a graver or other
small instrument of that description. Little more is
known of its natural history, than that it is found in
the interior of Asia Minor, and brought down to
Smyrna for sale. The white and black varieties of
Turkey oil-stone differ but little in their general cha-
racters; the black is, however, somewhat harder, and
is imported in larger pieces than the white. The
rough : irregular pieces of oil-stone scarcely ever
exceed about 3 inches square and 10 inches long, and
are generally about "one-third smaller. . When out into
rectangular forms, it is done with the lapidary’s
slitting-mill- and diamond powder.. The blocks are
then rubbed smooth with sand or emery on an iron
plate. “The. piece .of oil—stone' is generally inlaid in a
block of wood, in which it is cemented with the putty
used by glaziers, and to avoid the deposition of dust,
a wooden lid is usually added. The lid is sometimes

covered with a thick piece of but? leather, which
serves to absorb the oil from the tool, and is used in
the manner of a razor-strop.” Sperm or neat’s-foot
oil, or an oil not disposed to thicken, should be used.
Many persons find it difficult to use the hone in
setting their razors, and are quite unable to produce
the exquisite edge which cutlers give. For such
persons, Mr. Fayrer’s swing hone may be useful. ' It
consists of a flat and parallel slip of brass, a, Fig.
1155, formed like a hone, but with pivots at the end,






Fig. 1155.
by which it is mounted in two notches, d d, of a frame,
0 c, so as to swing and accommodate itself to the angle
at which the razor or other instrument is applied to
it. e e are two boxes, one to hold a coarse, and the
other a fine, powder. One side of the brass, marked
R, is first used with fine oil-stone powder and oil,
afterwards the other side with pulverized water-of-Ayr-
stone and oil, and the razor-strop is then resorted to.
Small pieces of this stone are out into slips of
different forms for the use of the lapidary and others.
Oil-stone powder is also used for grinding together
the brass or gun-metal fittings of mathematical instru-
ments ; and this powder is preferred tojpumice-stone
powdertfor polishing superior brass works.
The following are the analyses of a few polishing
stones :— '


g‘ g .s
"a a: CI
<2 :72 .4 .1." 3 S o<
Polishing slate. 4'0 835 8'5 6 9'0
- 7'0 66'5 1'25 2‘5 19'0 1'5
Bohemianstone. 1'0 790 1'0 140
Turkey hone. 3'33 720 1333 10-33


In our article CU'rLEnY, we referred the setting of
razors to the present article: we will therefore con-
clude with a few details on this subject. A razor
may be defective from being note/zed, from having a
wire edge, or a Want obt‘ase edge. Notches arise from
brittleness of the metal, occasioned by overheating
in the forging or hardening. There is no remedy for
this defect, unless, indeed, it has merely been left too
hard in the tempering, when it may, perhaps, be
remedied by tempering a little lower than at first.
The wire edge in a new razor arises from the use of
the glazers and polishers used in the manufacture.
As these revolve away from, and not towards the
edge, they always leave a thin filmy edge. The wire
edge may also occur from the excessive use of the
hone, “ as when the two faces of the wedge are
rubbed away beyond that point at which they first
meet, a slender film of steel begins to form, because
the extreme edge is then so thin, that it bends away
from the hone instead of being rubbed ofl’.” The
blunt obtuse edge is often occasioned by an excessive
use of the strep, or after grinding, the hone has not
HONE.
19
for if soft, and with a large quantity of dressing, the
been sufficiently used.‘ The rounded edge may occur
from the use of a soft strop; the leather against the
edge being‘ indented, rises as an abrupt angle, and
injures the keenness of the blade.
The whetstones used in setting razors should be
perfectly flat on the face: they should be always
supplied with oil, and be kept clean. In a new razor,
or an old one just ground, the Gharnley forest stone
is used for striking off the wire edge. The Turkey
oil-stone and the green hone, or Welsh hone, are also
used; but the yellow German hone is to be preferred
to all. Slabs of haematite iron ore are also'occasion-
ally employed for giving the final edge.
In striking off the wire edge “the blade is grasped
in the right hand by its tang, and near to the cutting
part, and is placed square across the one end of the
stone, but tilted about 10° or 20°, and is then swept
forward along the stone, edge foremost, in a circular
arc, so as to act on the entire edge: each side in
general receives only one stroke, and this produces
a comraratively obtuse edge, measuring from 40° to
60°. Should this fail to remove the wiry edge, the
blade is placed perpendicularly upon, and drawn with
a little pressure across, a strip of horn, (generally a
spoiled razor handle,) which is fixed down to the
bench, the friction of the horn against the edge gene-
rally suffices entirely to remove the wiry film, other-
' wise the blade is struck once more on each side along
the stone. Should the fihn of steel be left in the
stone, it is removed before another blade is applied.”
The razor is then set on the German hone. It is held
as before, but placed quite fiat down so as to touch
on the back and edge. “ Some prefer a long sweep-
ing stroke backwards and forwards, others prefer
small circular or elliptical strokes, and'others a short
zigzag movement, but all gradually work from heel
to point, or draw the razor forward so as to act on
all parts alike, and most persons lift the razor end-
ways towards the conclusion, allowing its point still
to rest on the hone with the view of sharpening the
circular end of the blade.” The razor must be turned
over at short intervals so as to whet it upon its oppo-'
site sides alternately; but it is usual “ to conclude
the process by sweeping the razor edge foremost once
on each side steadily along the hone, as if in shaving
off a thin slice of the hone: this lessens the disposi-
tion to the wire edge.” The process must be con-
tinued until the new facets, constituting the wedge of
17° to 20°, exactly meet at the extremity of the
more obtuse angle given by the striking off. Should
the wiry film still form, it must be removed by draw-
ing the blade across the slip of horn, and continue
the whetting for shorter periods on each side. If the
film is very minute, some persons leave it to be re-
moved by the strop; but the hone must not be given
up until the notches are no longer perceptible, and
the edge, when viewed edgeways, does not present
any visible thickness or width, but only the meeting
of the two sides of the blade. The razor may now be
slightly stropped, drawing it backwards from heel to
point. The strop should have a hard surface, and
only a very moderate quantity of abrasive matter;

edge of the razor is very liable to be turned round.
Mr. Holtzapffel recommends for the razor-strop a fine
smooth surface of calf-skin, with the grained or hair-
side outwards, pasted or glued down flat on a slip: of
wood. Almost any. extremely» fine powder, mixed
with a little grease and wax, will do for the dressing,
such as impalpably fine emery, crocus, natural and
artificial specular iron ore, black lead, or the charcoal
of wheat straw. The puffing advertisements and
affected mystery of some strop—makers are unworthy
the character of honest tradesmen. One side of the
strop should be left plain for the finishing stroke, and
the sheath, intended to keep the strop clean when not
in use, should always be put on the same way, to pre-
vent any of the dressing from being carried over to
the plain side.
It is recommended by some to strop the razor
immediately after use ;'others, on the contrary, advise
that it should simply be wiped dry ‘on clean wash-
leather, or a soft towel, and not stropped until it is
used again. We have tried both methods, and prefer
the former. Although it is likely that many of the
rules respecting razors are dictated as much by fancy
as by reason, yet there does seem to be some grounds
for the preference. In the operation of shaving we
would recommend a cold lather for the face, the usual
supply of hot water to be merely used for dipping the
razor, which may be done once or twice during
shaving, and again just before stropping. Now the
effect of these dippings is to raise the temperature of
the blade, and cause its. edge to yield readily to the
strop ; then, during the repose of 241 hours, it cools
down, and settles into that condition of edge which
was imparted to it by the final stropping; and ifuthis
be skilfully and judiciously done, the razor is in prime
condition when the time for shaving again comes
round. If, on the contrary, the razor be dipped into
hot water and stropped just before being used, the
effect is too abrupt and sudden to allow of those
molecular changes which we may suppose to take
place on allowing the metal time to adjustitself. on
cooling down. But whatever course be adopted, one
thing is certain—unless the strop be used with great
moderation and caution, it is always likely to do more
harm than good. .
After the razor has been frequently set, it becomes
so'wide in the bevil or facet as to require re—grinding
to thin it away. The cutler tries the keenness of the
edge by making a faint incision in the thick skin,
covering the inner edge of the palm of the left hand;
he also tries it upon the thumb or finger-nail, placing
it in a line with the finger, and obliquely across the
end of the nail, or at right angles to the finger, allow-
ing it to rest upon the back of the nail: the nail of
the third finger is considered the most sensitive. In
this way a very minute notch in the edge is quite
perceptible: the keenness is also judged of by the
degree in which the razor hangs to the nail, the keen
blade making the deeper incision, and offering a drag-
ging but smooth resistance, while the blunt razor
slides over with less penetration and drag. - Mr.
' c 2
so‘
HONEY-STONE—HORN.
Kingsbury proposes the use of a magnifier for
examining the entire edge. Under a microscope of
a linear power of 50 to 100 the edge presents a
faintly undulating and irregular line, resembling a
ripple mark. Indeed, the edge of a good razor bears
this severe scrutiny much better than most of the
productions; of art. .
HONEY. See Susan.
HONEY-STONE, or MELLITE, a rare mineral,
found in small solitary octohedral crystals of a honey-
yellow colour, among the layers of wood-coal at Artem,
in Thuringia. It contains an organic acid, the militia,
(C4H04,) and is in fact itself a mellitate of alumina.
HOPS. See BEER, vol. i. p. 113.
I—IORDEINE. See BEER, vol. i. p. 112.
~ HORN. The term horn is commonly applied to
any hard projecting body on the head of animals,
serving as a weapon of defence; but it is strictly ap-
plicable-only to a certain class of such weapons. ‘For
instance, the antlers of the stag consist entirely of
bone, and have no right to the denomination “horns ;”
the weapons of the ox, the sheep, and the antelope,
consist of a sheath of true horny material on a bony
core; while the horns of the rhinoceros are wholly
composed of horny matter. Bone and horn are as
distinct from each other as both are from ivory; yet
the three are often confounded by the application of
the general term “horn” to antlers, tusks, and true
horns. Besides the horns on the head of animals,
there are other horny processes in the hoofs, claws,
nails, &c., and there are various modifications of horn,
in the scales of the armadillo, the plate-armour of the
tortoise, ‘the spines of the porcupine and hedgehog,
and the quills of birds.
Horn consists principally of membranous animal
matter, being a compound of coagulated albumen,
gelatine, and a small ‘portion of phosphate of lime. It.
has been well remarked of these proportions, “ had
the horns much more earth, they would be brittle like
bones; had they much more gelatine, they would be
soluble like jelly or glue 5” as it is, they are easily
convertible to the purposes of the manufacturer, by
whom they are so largely used that considerable im-
portations of horns are necessary, in addition to the
supply afl’orded by this country.
The horns chiefly applied to manufacturing uses are
those of the bull and cow, with the hoofs of those
animals. Large quantities are imported from Russia,
South America, and Southern Africa. The horns of
the bison and bufl'alo are also in demand, the latter
being frequently reserved, on account of their beauty,
for'su'perior purposes. The horns of the chamois and
antelope are polished and used in their natural forms.
The first process in the manufacture of horn is that
of detaching it from the bony core : this is dpne by
maceration of the whole horn in water for a month
or sixfweeks, when the membrane which attaches the
born to the core is destroyed by putrefaction, and the
two become easily separable. The cores‘, when burnt
to ashes, form the best material for the small tests or
cupels “employed by the assayers of gold and silver.
' The tips of the horn are then sawn. off, these being

entirely solid, and adapted for cutlery purposes, for
the button-manufacture, &c. The remainder of the
horn is then either cut into short lengths, or soaked
entire, according to the use to which it is to be ap-
plied. Immersion in boiling water for half an hour
greatly softens the horn, but the effect is afterwards
heightened by holding it in the flame of a coal or
wood-fire, when it becomes exceedingly soft, and can
be easily slit up the side with a knife. It is now
opened by means of pincers, and spread out nearly
flat. In order to obviate the risk of scorching the
horn over an open fire, Mr. James employs a sort of
iron mould, with a conical iron plug. These are
heated at a stove to the temperature of melting lead,
and the horn cut lengthways with a saw or knife is
inserted in the mould. The plug is then gradually
driven in with a mallet, and in about a minute the
horn is softened and ready to be opened in the usual
manner. The “ flats,” as they are called, are then
inserted either between iron plates, previously heated
and greased, or between wooden boards, and are sub.-
jected to a certain amount of pressure, varying ac-
cording to the intended use of the horn. If it is to
be used in lanterns, the pressure is continued until
the substance of the horn is separable into distinct
plates. These are laid singly on a board covered with
bull’s hide, and scraped with a draw-knife, having a
wire edge. When reduced to the proper degree of
thinness, they are polished, first with a woollen cloth
dipped in charcoal-dust and water, then with rotten-
stone, and finally with horn shavings. The largest of
the fihns of horn which come off during these pro-
cesses, are often dyed and‘ cut into various forms,
when they become highly sensitive, and curl up by
the mere warmth of the hand. Toys of this descrip-
tion were originally brought from China, hence they
are commonly called Chinese sensitive leaves.
For general purposes the pressure given to horn is
very moderate, especially, for combs, where too much
pressure causes the teeth to split. Heat and pres-
sure applied to light-coloured horn, render it trans-
parent; but artificial colour is given to the greater
part of the articles fabricated of horn. This is easily
done by boiling the horn in infusions of colouring
ingredients. The rich red-brown, employed to imitate
tortoiseshell, is obtained by mixing pearlash, quick-
lime, litharge, and a little pounded dragon’s-blood, in
a sufficient quantity of water. This preparation, after
boiling half an hour, is applied hot to those parts
of the horn which are to be coloured, and is left
some time on the surface. A deeper tinge in particu-
lar parts is obtained by repeating the application. A
blacker brown is produced by omitting the dragon’s-
blood. , '
For drinking-‘cups the horn is cut into lengths be-
fore it is softened, and when the scalding and roasting
processes have been gone through, it is not slit, but
placed while hot in a conical mould of wood, a conical
wooden plug being also driven in, to press the horn
to the true shape. When cold it is taken out of the
wooden mould, and fixed by the large end to the man-
_ dril of a lathe, where it is turned and polished, and
HOROLOGY.
21
a groove formed to receive the bottom. This is out
out of a flat piece of born by means of a crown saw,
and is dropped into the horn, and forced into the
groove, the horn having been previously softened
before the fire, enough to admit of the necessary ex-
pansion. Contracting as it cools, the horn fixes the
bottom so firmly as to make it perfectly water-tight.
For knife-handles and other works where horn re-
quires to be moulded, the process is as follows. The
horn is first cut with a saw into convenient pieces,
and then heated until soft enough to be pared and
shaped with a knife into somewhat of the required
form. The pieces are then pressed into moulds'con-
sisting of two dies, or pieces of metal having cavities
sunk in them 5 these cavities to be either’ straight,
curved, twisted, or engraved in any device, according
to the pattern to be produced. This mould, with the
horn enclosed, is placed in a clamp worked with a
powerful screw, the mould and horn having been
dipped in boiling water for a few minutes previous to
being subjected to its action. After 20 minutes’ pres-
sure the work is ready for finishing, which includes
scraping‘ and bufiing with Trent sand and oil, and
afterwards with rotten-stone and oil. Horn is some-
times used by watchmakers as a vehicle for the appli-
cation of polishing powders to flat works.
The ancient uses of horn include its conversion into
bows, examples of which are still found in India and
China 5 its use as a musical instrument, (the horn of
the wild bull tipped with silver, and slung in a silver
chain, having been the true bugle-horn of former
times 5) its employment in windows before the dis-
covery of glass, and its conversion to purposes of
defence, a complete suit of scale armour made of horn
having been seen and described by Mr. Aikin, to
whose Lecture on Horn, delivered before the Society
of Arts, and printed in their Transactions, vol. lii,
we are indebted for many of the above particulars.
HORNBLENDE, an essential constituent of cer-
tain rocks, as syenite, trap, and hornblende-slate. It
occurs in black and greenish-black crystals and massive
specimens : often in slender crystallizations, like ac-
tinolite, and in short thick crystals. Its dark colour
is due to oxide of iron. Its composition is, silica 438.8,
magnesia 13'6, lime 10'2, alumina 11'5, protoxide of
iron 3'5, protoxide of manganese 1'15, hydrofluoric
acid and water 22.
HORN LEAD. See LEAD.
HORN SILVER. See SILVER.
HORN STONE. A variety of rhomboidal quartz,
used for grinding fiints in pottery mills. It is called
chart in Derbyshire.
HOROLOGY, (from cé'pa, an hour, and he'yew, to
tell,) is that branch of the useful arts which describes
the action of the various machines used for the pur-
pose of measuring time.
It is not easy to give a good definition of time.
According to Locke it is “the consideration of dura
tion as set out by certain periods, and marked by
certain measures or epochs.” According to Aristotle
“ our conception of time originates in that of motion;
and particularly in those regular and equable motions

carried on in the heavens; the parts of which, from
their perfect similarity to each other, are correct
measures of the continuous and successive quantity
called time, with which they are conceived to co-exist.
Time, therefore, may be defined—the perceived num-
ber of successive movements.”
There is no doubt that the regular periodical move-
ments of the heavenly bodies gave rise to the measure-
ment of time and the present method of dividing it.
The space between the rising and setting of the sun
has always been called a clay, and that between the
setting and rising of the bright luminary, a ate/it. The
moment the sun attains his greatest altitude is called
aooa for that day 5 and the time from one noon to the
next is called a solar day. These effects are produced,
not by the motion of the sun, but by that of the
earth: the circumference of the latter is divided into
360°, so that by turning on its axis each of these
degrees is brought to the meridian once in 24: hours,
and 3-2;? = 15: hence, as 15° pass under the sun
during each hour, 15° of longitude mark 1 hour of
time. Berlin is nearly 15° to the east of London, so
that it is almost 1 o’clock in that city when it is 12 in
London.1L The space of time between two appear-
ances of a fixed star in the same spot, with reference
to some terrestrial object, is the period of the earth’s
actual revolution, without reference to the sun, and is
called a sz'eZereaZ day. This is divided into 2% equal
parts, called hours; an hour into 60 equal parts,
called minutes ,- and a minute into 60 seconds. The
year, or one revolution of the earth round the sun, is
divided into 365 equal parts or days, and forms what
is called mean time; while time, as naturally divided
by the apparent motion of the sun, is called true or
apparent time.
The earliest instruments invented for the purpose
of measuring time were saa-dz'als, and CZeps‘z/etree.
The principle upon which sun-dials are constructed
may be readily understood by supposing the earth to
be a transparent sphere, Fig. 1156, with 24: equidis-
tant circles a, 5, e, at, &c. marked upon it, all passing
through the poles: then, as the earth turned round
upon its axis N s in its daily motion, each circle
would pass in succession under the sun, or, in other
words, the sun would be in the plane of each circle;
and as the axis of the earth is in the plane of all
these circles, if such axis were represented by an
opaque body, such as a rod of metal, its shadow would
be cast on the concave half of each circle in succes-
sion at the end of every hour, or the 24th part of
each revolution. But as the distance of the sun may
be regarded as indefinitely great when compared with
the size of the earth, any small transparent globe,
with hour-circles marked upon it, passing through.
the poles, and with its axis parallel to the axis of
the earth, would, if made to revolve regularly in 241
hours, present the same appearances as the earth

(I) This will explain some of the apparently marvellous state-
ments which we see in the newspapers respecting messages trans-
mitted by the electric telegraph. Thus, if a message dated 1 o’clock
were sent from Berlin to London, and 30 minutes. were occupied
in its transmission, it would be received in London at 112-30, or
half an hour by the clock before it had left Berlin.
22
HOROLOGY'.
on the above supposition: the shadow of the opaque
axis N s would fall in succession upon the hour-
circles. Now if this small globe be cut by a plane,
A B, passing through its centre parallel to the


Fig. 1156.
SUN-DIAL.
horizon of the place where the. experiment is being
conducted, and straight lines be drawn from» the
centre of the sphere to those points of the hour-circles
cut by the horizontal plane; the shadow of the half
axis above such plane will fall on those lines in suc-
cession every hour. In the construction of a sun-
dial these lines are drawn by simple geometrical rules
upon a flat surface supposed to represent the cutting
plane A B ; and a piece of metal, called a gaomoawith -.
a sharp edge, called the style, is fixed on the surface,
so that this style shall be truly- parallel with the" axis
of the earth at the place of observation, then the
shadow of this edge moves from one line to another
in» an; hour. This forms the horizontal szm-(lz'al. A
vertical dial for‘ fixing against an upright wall may be
formed by cutting the globe with a. vertical plane, 0 D,
instead of the'horizontal one, A B; in which case the
planes of the circles will cut the upright plane in
straight lines radiating from the centre of the sphere
or of the. circle; and the lower half of the axis will
become the style of the dial.
The word elepsyca'a is from the Greek Khe’a-rco, to
steal, and z'i‘o‘wp, water, as indicating that the course of
time was marked bythe sleall/zy flow of water. If
i a vessel of water be kept full by a stream running
into it, and a hole be made near the bottom, the water
will- flow from the hole and fill a second vessel at,
a uniform rate; and this second vessel may have its
sides graduated, or carry a floating index pointing to
a graduatedplate divided into hours, and even mi-
nutes, provided the index rise fast enough to distin-
guish, them. When the index arrived at the top it
might beimade to open avalve, let out the water, and
descending to the, bottom close the valve, and again
commence itsv ascent: if it were contrived that this
should take place every 12 hours, it would form a
self-acting. clock, requiring no aid except from the
stream. But vif a vessel; be filled andv graduated
ac'cordingt'o the rate at'which water flows out, which
is not uniform, but varies as the square root of the
PRINCIPLE ‘OF THE HORIZONTAL AND VERTICAL '
a as ornaments or curiosities.

height above the hole at which it stands, this will
also serve for a clock until the vessel is empty.
l-Holllowi caps, with a hole in the bottom, were some-
times used to measure time: ‘one of these being
floated upon‘ water would gradually fill and sink in
an ascertained period. The burning of a candle or
portions thereof also served the purpose of indicating
divisions of time. Saacl is in one respect preferable
to water for measuring time: itv flows through an
orifice with very nearly equal velocity, because the
pressure among its particles is not transmitted in all
directions, as in the case of water. ‘The saazel-glass is
so contrived, that a quantity of sand shall flow from
one bulb of glass into another through a short tube
or orifice connecting the two, in an, hour, half-an-
hour, or any other portion of time, and at the end of
one period, another can be marked simply by invert-
ing the glass.
All these contrivances for marking the course of
. time are so very inferior to theclock, that upon its
introduction they were either superseded or retained
The invention of the
clock is of much later date than some writers have
supposed; for although the term lzorologz'am is met
with earlier than the middle of the 14th century, the
period assigned for the invention, that term was pro-
bably applied to all instruments used for marking the
progress of time. The first clock is said to have been
erected at Bologna in 1356. In 1364, Hemy de
Wyck, or Henri de Vic, a German artist, placed a
clock in the tower of the palace of Charles V. The
introduction of clock-work into England was probably
in 1368, when Edward III. granted protection to
three Dutch horologiers, who had been invited from
Delft. About 1370 a clock was erected at Strasburg ;'
about the same period Gourtray had a clock, ‘which
was removed by the Duke of Burgundy in 1382.
There was a clock at Spire in 1395 ; at Nuremberg
in 14.62; at Auxerre in 1&83 ; and at Venice in 1497.
By the end of the 15th century clocks were not un-
common in private families on the continent, and it’
is probable also that they had become general in Eng-
land; for Chaucer uses the terms “ clock” and “ abbey
orloge,” in the way of familiar illustration. Accord-
ing to Berthoud, the clock, such as that erected by
Henry de Wyck, is not the invention of one man,
but of many men at difi‘eren't periods, and the
following may be regarded as the principal steps in
the invention :—--1 . The use of wheel-work, which was
known and applied in the time of Archimedes. 2. A
weight, used as a maintaining-power: this would
probably be accompanied by a fly to regulate the
‘velocity. 3. The ratchet-wheel and click, for winding‘
up the weight, without detaching the teeth of the
great or main wheel from those of the pinion in
which they were engaged. 4h. The regulation by
a fly being variable according to the varying density
of the atmosphere, 850. would lead to the invention of
the alternating ‘motion of the balance, and this would
require an eseapemeat of some kind. 5. These last
two inventions would‘ induce great regularity in the
motions of the wheelwork, and would have suggested
HOROLOGY.
23
the dial-plate with a single hear-hand or pointer ,-
modifications, in fact, of the sun-dial plate and the
gnomon: the minute-hand was a later contrivance,
and the seconds—hand still more recent. 6. The
sari/slay part, to inform persons at a distance of the
hour. 7. The alar'am, or alarm, originally invented
for the purpose of arousing the priest to his morning
devotions. _
Such appear to be the successive steps by which
the clock attained a considerable degree of efficiency
as a time-measurer. All great inventions are ad-
vanced towards perfection by a similar combination
of the labours of many minds, and it may be taken
for granted that Do Wyck’s clock was no exception
to the general rule. One of the first applications of
the clock was for astronomical observations, and we
find that some of the most important improvements
in clock-work are due to astronomers.
It is uncertain at what period the clock was made
portable; but as early as 1530 it was proposed by
Gemma Erisius to use a portable clock for the pur—
pose of ascertaining the longitude at sea; and in
154A the corporation of master clock-makers at Paris
obtained a statute from Francis 1., whereby any one
not an admitted master was forbidden to make clocks,
watches, or alarums, large or small. In making clocks
portable, the substitution of a main-spring for a
weight, as the maintaining-power, must have been
made : this, with the invention of the fasee, introduced
a new era into the art of horology.
The next great discovery in the art was the law of
z'soehrom'sm of the pemlalam, made by Galileo while
pursuing his studies at Pisa about the year 1581.1
In 1583 he recommended the pendulum to be used in
measuring time. In his first applications of it to
astronomical observations he employed persons to
count and register the oscillations, but he soon in-
vented means for effecting this by machinery, and
fifty years later he describes his “time-measurer,” or
pendulum~olock, “ the precision of which is so great,
and such, that it will give the exact quantity of hours,
minutes, seconds, and even thirds, if their recurrence
could be counted; and 1ts constancy is such, that two,
four, or six such instruments will go on together so
equally, that one will not differ from another so much
as the beat of a pulse, not only in an hour, but even
in a day or a month.” The honour of first applying
the pendulum to a clock has been also claimed by
Huyghens, who before the year 1658 certainly super-
intended the making of a pendulum-clock, and whose
excellent treatise “De Horologz'o Osez'llz'laez'o” led the
way to many of the subsequent improvements in
clock-work. He showed that the larger arcs of vibra-'
tion of a pendulum occupy rather more time than
the smaller, and that the time of a semicircular vibra-
tion is to that of a very small one, as 34 to 29. It
should, however, be stated, that a countryman of our
ownf-is entitled to some share of the honour which
has been’ contested by Galileo and Huyghens; for in

(1) It is stated that the Arabs, as early as A.D. 1000, were
acquainted with this property of the pendulum, and used it as
a correct measure of time.

1641 Richard Harris made a long-pendulum clock for
the church of St. Paul’s, Covent-garden. It has how-
ever been suggested that Inigo Jones, the architect,
having been in Italy during the time of Galileo, may
have communicated to Harris what he had heard of
the pendulum. Huyghens also constructed amarine-
clock, and he discovered that its pendulum vibrated
more slowly as its approached the equator, which led
the way to the subsequent discovery of the oblate ‘
spheroidal form of the earth. He also discovered that
the isochronism‘ of the pendulum is true only when
the ball moves in the involute of a cycloid; hence
cycloidal eheehs were contrived for causing the ball to
describe that curve; but as no substance could be‘
found of sufficient strength and flexibility to form
a thread which should easily wind on the cycloidal
cheeks, and of such a nature as not to adhere to them,
the cycloidal pendulum, although perfect in theory,
was found to be inferior in practice to the common
pendulum ; for when this vibrates in very small arcs
of a circle, its vibrations are, for all practical pur-
poses, isoohronous, because the circle has the same
curvature as the cycloid at its lowest point, and may
be taken as identical with it for a small distance.2
In 1676, a London clockmaker named Barlow
invented the repealing mechanism, by which the hour
last struck may be known by pulling a string. Much
ingenuity was also thrown away upon the construc~
‘ tion of clocks for showing both mean and apparent
time. The most important invention of this period
was the anchor eseapemehl, the invention of which
‘has been referred by some to Dr. Hooke,3 and by
others to Clement, a London clockmaker. “ The
great advantage of this escapement over the old
crown wheel is, that it allows the escape to take place
in a small angle of vibration, thereby preventing the
necessity for the maintaining power acting upon the
pendulum with so great a force as by the old plan;
and by the introduction of a heavy ball, leaving that
to be done by the uniform power of gravity, which
before was dependent upon the impulse given by the
wheel to the pallets. This change in the escapement
introduced the practice of suspending the pendulum
by a thin and flexible spring, another invention of
Clement’s ; although this has also been claimed for
Dr. Hooke. The seconds pendulum with this escape-
ment was called the royal pemlalam. '
The next great invention in the art, was the intro-
duction of the aompeasalioh principle for counteracting
the effects upon the length of the pendulum of
changes of temperature. In 1715, George Graham.

K2) The properties of the pendulum are stated at some length
in the Editor’s small work on Mechanics, published in Weale’s
Rudimentary Series.
(3) Hooke, having found that the real merits of pendulums had
been obscured by making them vibrate in very large arcs, con_
structed in 1656 a clock which moved with astonishing uniformity:
his pendulum was long and heavy, and was made to swing in
very small arcs, and it is thought that he could not have attained
to such a result, without a. knowledge of the anchor escapement.
Clocks on this construction were found to excel those with
cycloidal pendulums; and Huyghens himself showed that the
error of 1,1,0 inch in the formation of the parts which produced
the cycloidal motion would cause a greater irregularity than a
circular vibration of even 10° or 12° could do.

242
HOROLOGY.
substituted a jar of mercury for the pendulum ball,
and thus succeeded in retaining the point of suspen-
sion and the centre of oscillation at the same distance
from each other. Graham also suggested the idea of
making use of the opposite expansions of different
metals as a compensation for a pendulum; an idea
which was realized by Harrison, who also introduced
it into the balance wheels of watches, and succeeded
in constructing a timekeeper which determined the
longitude within such limits as to procure for him, in
1767, after much previous trial and inquiry, the par-
liamentary reward of 20,0001. Harrison also invented
the goz'vzgfusee, by which a watch can be wound up
without interrupting its movement.
It would be quite impossible within our limits
even to notice the variations and improvements in
clocks and watches which have been made within the
last 50 or 100 years. Escapements alone have formed
a theme for constant variation; and this is so
favourite a subject, that almost every person of a
mechanical turn has either made or planned some
novelty in this way. Indeed, a celebrated clockmaker
is reported to have said, that for a wager he would
undertake to invent a new escapement every morning
before breakfast.1 It is, however, important to notice 7
in this place the distinction between the recoil escape- <
meat and the (lead-beat escapement. In the anchor
escapement, already noticed, the pendulum vibrates
some distance after the tooth has performed its oflice
of impelling the pallet forward; the effect of which
is to give a recoil or retrograde movement to the
wheel, which may be noticed in the seconds hand
of any common house clock. In such a clock this
effect is of no great consequence, and as this recoil
' escapement is easy to make, it will probably continue
in use. But for astronomical and other good clocks
the recoil is objectionable as a source of error;
Graham therefore contrived the dead-beat escapement,
in which, however far the pendulum may swing, no
recoil can take place. The duplex and remorztoz're
escapements will be noticed hereafter.
Wooden clocks have been in use for about 200
years. They were first produced in Holland, and
hence called DZttG/b clocks; but the manufacture has
for a long time been mostly confined to the Duchy of
Baden. Ornamental drawing-room clocks are still
largely manufactured in France.
Dismissing historical details, we will now endeavour
to lay before the non-professional reader a brief
statement of the principles of horology.
It is a principle of mechanics that in every uniform
motion, the. ‘spaces described are proportional to the
times occupied in describing them. Such a motion
is well adapted to the measurement of time, since it
refers this measurement to that of the spaces de-

-(1) See Mr. Adam Thomson’s “ Time and Time-keepers,” p. 147.
The English appear to have monopolised the inventions in this
important branch of the'art. The inventor of the vertical escape-
ment isv unknown; the horizontal or cylinder escapement is by
Graham; the lever escapement by Mudge, the duplex by Dr.
Hooke, and perfected. by Tyrer. The detached escapement,
although invented by Berthoud, owes its accuracy to the improve-
ments made by Arnold and Earnshaw.

scribed by the moving body. Hence in the construc-
tion of time-measurers the first thing required is the
means of producing a uniform motion. But, in order
that a machine may always move with the same
velocity, the force which moves it must always be in
equilibrium with the resistance which it has to over’
come. If the resistance continue constant, the
power will constantly act with the same intensity:
if the resistance vary, the power must vary at the
same rate, in order that equilibrium may not be dis-
turbed. In the motion of a machine the number of
resistances of various kinds is so great, and liable to
such constant variation from changes in temperature,
in moisture 850., that it does appear at first view
extremely difficult so to arrange the power that it
may be constantly in'equilibrium with the resistances.
In clock and watch work, these difliculties are rather
eluded than overcome, as we shall now endeavour to
explain.
The power employed to impart motion to instru-
ments for measuring time, may be either a weight or
a spring. ‘This, in either case, is called the maintain-
my power.
In order that a weight
may act as a maintaining
power, it is suspended
‘from the extremity of a
cord which is coiled round
a short cylinder moving
on a horizontal axis, the
other extremity of the
cord being attached tothe
cylinder. See Fig. 1157.
As the weight tends con-
stantly to descend, it com--
municates a rotatory mo-
tion to the cylinder,
which motion can be
transmitted to the me-
chanism of the clock by Fig-1157-
means of a toothed wheel attached to the cylinder-
The springs em- ,,
ployed as moving ' ‘
powers in time-
pieces, are long
thin ribbons of
steel, coiled up in—
to a spiral form as
in Fig. 1158. The
outer extremity of this spring (called the main-spring)
is attached to a fixed point, while the inner extremity
is fastened to an '
axis, which being
turned round in
the proper direc-
tion, carries round
with it the interior
extremity ' of the
spring, wherebythe
spiral coils are
brought closer together, and the spring assumes the
form of Fig. 1159. Now as the spring tends con-


‘ Fig. 115's.
iiIllllllliiliiiti _


HOROLOGY. 25
stantly to uncoil or to assume its original form, it
‘will in doing so cause the axis to rotate, and this
rotatory motion is communicated to the mechanism
of the clock or watch by means of toothed wheels
and pz'az'oas. It is evident that this arrangement
may be so far altered that the inner extremity of the
spring may be fixed, while the outer extremity, being
attached to apiece of mechanism capable of revolving
round the axis of the spring, it would equally com-
municate a rotatory motion to this piece.
If we compare the action of the spring with that of
the weight, an important difference will be discovered.
The weight acts always with the same intensity,
while the force of the spring goes on constantly
diminishing from the moment when it begins to
uncoil until it has reassumed its primitive form, Fig.
1158. The uniformity of action in the moving power,
so necessary to the proper going of a time-keeper, is
secured by employing a descending weight as in a
clock, but where there is no space for a weight, or
where portability is required, and a spring must be
used as the moving power, its action is made uniform
by an ingenious contrivance called the fuses. The
spring is enclosed within a short cylinder A, Fig
1160, named the barrel, to the surface of which is
fixed the extremity of an articulated chain B, which,




ll '1‘: ' ' III"!
is wily] l par
. s2“;
L
5%
5i
.5
*2
2.
Fig. 1160.
after being coiled a certain number of times upon the
barrel, is attached by its other extremity to the lower
part of ‘a conical piece C, called the fusee. This fusee
is furnished with a helical groove for receiving the
coils of the chain. When the spring is completely
stretched, the chain exactly fills the grooves of the
fusee, with the exception of the small piece which
proceeds from the narrowest portion of the fusee to
the barrel. The force of the spring in uncoiling,
causes the chain to unroll from the fusee and to roll
upon the surface of the barrel, and this action con-
tinues until the chain is completely detached from
the fusee, except that small portion which stretches
from the larger base of the fusee to the barrel. Now
it is evident that during this motion the tension of
the chain, depending as it does upon the force of the
spring, goes on constantly diminishing 5 but as this
tension acts upon the fusee at the extremity of a
lever which gradually increases in length, the curve
of the fusee has been so determined that there shall
be an exact compensation 5 that is to say, the action
of the chain produces the same effect as a constant
force applied to the extremity of a lever of a constant
length.

It will therefore be understood that the fusee is a
variable lever, upon which the main-spring acts
through the medium of the chain. “ A common
observer would say of the fusee that it was a sort of
cone, upon which the chain was wound from the
barrel, by the operation of winding up the machine;
but it is in reality a mathematical curve, which has
this peculiar property,—-that as the chain winds upon
it, the distance from the centre of motion of the fusee
to the semi-diameter of the chain which is in contact
with it, continually varies 5 and also that it varies in
this proportion, viz. that the distance of the centre
of motion of the fusee to thesemi-diameter of the
chain, at that point where it leaves the fusee for the
barrel, multiplied by the force of the main-spring
acting on the chain at that time, shall be what
mathematicians term ‘ a constant quantity : ’ that
is, shall be the same whatever point of the fusee may
be taken. Thus: suppose the chain which receives
its power to turn the fusee‘ from the main-spring
pulls with a force of 9 oz., and that the distance from
the centre of motion of the fusee to the semi-diameter
of the chain at that part where it leaves the fusee is
42 hundredths of an inch, or expressed decimally,
‘4:25 then 9 X ‘4:2 :: 378. Now let the spring be
wound up to different points, at which its force will
be respectively 12 oz., 18 oz. 20 oz., 30 oz., and A0 02.,
the corresponding distances at which the chain must
pull from the centre of the fusee will be respectively
‘315, ‘210, ‘189, ‘126, and "09445 of an inch, for
‘315 X 12:3'78, '21 X 18=3'78, ‘189 X 20=3'78,
‘126 X 3O==3'785 and ‘0945 X 40:378. Thus at
any given distance from the centre of motion of the
fusee, its power to turn any machinery is uniformly
the same; and as the great or main wheel which
communicates motion to all the rest in the watch or
chronometer, is attached to the fusee, their centres of
motion coinciding with each other, it follows that the
power at the teeth of the main wheel is perfectly
uniform.”
The maintaining power, whether it be that of a
descending weight or of a spring, is transmitted
through a train of wheels and pinions. It first turns
a central axis or arbor to which a spur-wheel is
attached: the teeth of this wheel engage with, or
look into, the spaces between the teeth of a smaller
wheel or pinion, which is fixed to a second axis
parallel to the first: this second axis also carries a
toothed wheel, which engages with a pinion fixed to
a third axis, and so on. Now if the main-wheel, or
that attached to. the first axis, have six times more
teeth than the pinion which engages with it, the
second axis will evidently turn round six times quicker
than the first; if the wheel of the second axis have
four times more teeth than its corresponding pinion,
the third arbor will turn round four times quicker
than the second, and consequently twenty-four times
quicker than the first. Thus it will be seen that the
rotatory motion of the first axis is transformed into
the rotatory motions of the second, of the third, of
the fourth, &c., coiistantly increasing in velocity 5 and
the relation between the velocities of two consecutive
28
HQROLO GY.
arbors will be that of the numbers of teeth in the
wheel or pinion which transmits the motion from
one to the other.
Having thus given a general idea of the arrange-
ment of the train of wheels and pinions in a clock
or watch, and of the power which sets them in
motion, we have next to show- how, this movement is
regulated so as to cause the hour, minute, and
seconds hands, to move uniformly over the surface
of a dial.
It has been stated that in order to render the
motion uniform, a permanent equilibrium must be
established between the power and the sum of the
resistances. For this purpose there may be attached
to the last arbor of the train, or that which has the
greatest velocity, certain pallets, which strike the air
during their motion. They are of the form shown at
ff’, Fig. 1161, and consist of a thin plate of metal, on
two opposite sides of
the axis with which
1, they revolve. The
at I; resistance which the
1 air opposes to their
pill" motion varies in pro-
2 portion to the square
' of their velocity, the
consequence of which
is that when the mo—
tion begins to be pro-
, duced, the resistance
Fiy-1161- experienced by this
fly, as it is called, is very small: the moving power
is too great to allow of equilibrium being at once
established, and the velocity of the whole train goes
on increasing. But this increased velocity increases
the resistance to the motion of the pallets, and the
mechanism soon attains such a velocity that the
power is in equilibrium with the resistances; the
motion then continues uniform, and remains so as long
as the power preserves the same intensity.
There are, however, objections to this method of
regulating the movement. The air which acts upon
the fly is subject to considerable variations in den—
sity; moreover, the least change in the magnitude of
the moving power, and in the friction of the different
parts, disturbs the equilibrium, and, consequently,
the rate of the whole mechanism. Hence the fly is
not used where the precision of a clock is required.
It is, however, used in the striking part of clocks, in
musical snuff-boxes, in smoke-jacks, in Garcel lamps,
850., but in such cases the moving power is a spring
which acts directly upon the train of wheels, so that
although regular at any given moment, the rate goes
on gradually diminishing until the spring has become
quite relaxed, and all motion ceases.
As the means just indicated do not produce a


l
~u i'lilll
l








motion sufi’iciently uniform for measuring time, a con-.
trivance has been invented for producing not a con-
tinuous, but a periodically uniform motion. A piece
of mechanism is made to oscillate in a regular
manner, so that at each oscillation the whole train
of wheels shall for a moment he stopped, thus pro-

ducing an intermittent motion, and the hands which
serve to indicate the time upon a dial-plate, instead
of turning with one continuous motion, advance by a
series of jerks; but each jerk passes over so minute
a portion of space that the eye cannot distinguish it
in the hour and minute hands, from an extremely
slow continuous motion; in the seconds hand,
however, this jerking motion is evident.
The piece which oscillates in the manner referred
to, is called the regulator; the apparatus which
connects the train of wheels with the regulator, and
serves to arrest at each instant the motion of the
wheel, is called the escapement.
The regulator employed in clocks and watches,
consists of a metallic wheel, tolerably heavy at its
circumference, moving upon an axis, to which it is
attached at the centre. This wheel is called the
lalaezce; its oscillations upon its axis are of course
produced by the maintaining power, the main-spring
or the weight, transmitted through the train of
wheels and the escapement. This will be evident
from Fig. 1162, which exhibits at one view the several
acting parts of a small portable time-piece, showing
the connexion of the different parts. For the sake
of clearness a few things have been omitted which
will be explained separately, and the arbors or axes
of the different wheels and pinions have been
lengthened so as to remove the parts to a much
greater distance ‘from each other than is adopted in
practice.1
A is the main-spring, the outer end -of which is
fixed to the base of the upright pillar; the uncoiling
of this spring gives a rotatory motion to the axial,
to which it is attached at its inner extremity. This
axis is furnished with a ratchet-wheel n, which acts
upon the spur—wheel o, by means of the click 0. The
wheel (3 gives motion to a pinion D, and consequently
to the wheel n, which in its turn moves the pinion r
and the wheel G; the wheel a imparts motion to the
pinion H, and the axis of this pinion causes the
scapewheel M to revolve by means of the crown-
wheel x and the pinion L. The axis of the crown-

(1) Fig. 1162 is copied from Berthoud’s fine old Treatise,
entitled “ Essai sur l’Horlogerie,” 2 vols. 41:0. Paris, 1763. We
are also indebted to this work for several other figures. We have
also consulted the splendid work, by the same authority, entitled
“ Histoire de la Mesure du Temps par les Horloges,” 2 vols. 4to.
New Edition, Paris, 1802. Also his “ Traité des Horloges
Marines,” 4to. Paris, 1773, and the Supplement, 1787.
The reader interested in the subject will also do Well to consult
Thiout’s “ Traité de l’Horlogerie, méchanique et pratique,” 2
vols. 41:0. Paris, 1741. This treatise is illustrated With 91 large
copper-plates, containing representations of the tools and engines
used in making the works, and in general use by the'clockmaker;
together with abundant illustrations of the different parts of clocks,
equation clocks, 8w. Although a great part of the machinery here
figured may be considered as more curious than useful, yet it
cannot be said to have been unproductive. The inventive inge-
nuity thus constantly stimulated and exercised in the production
of toys, produced also useful machines, and laid the foundation
for the modern school of engineering, which have turned out such
‘marvels as the Steam Engine, the Vertical Printing Press, and
the self-acting Spinning~mule. When a man of genius is engaged,
as George Graham was, in making a planetarium for the amuse-
ment of a nobleman, (Lord Orreiy, whence these things are called
0rrerz'es,) he is also enriching mechanical science with new mo-
tions, and new combinations, which can afterwards‘ be adapted to
_ far more important purposes.
I'IOBOLOGY.
27
wheel turns with one end in a branch 0 of the poz'erzee
I, and the other in the counterpotence J. Opposite
the scape-wheel M, the teeth of which are cut in
a particular manner, is the axis, or verge, of the
balance N; this axis is furnished with two pallets ii’,
placed at right angles to each other, and so arranged
with respect to the upper and lower parts of the
wheel M, as‘ to fall into the teeth thereof in such
a way that as the wheel rotates its teeth alternately
fit into one pallet while the other is escaping there-
from. The pallet 2' receives an impulse which causes
it to move from the front to the back ; but soon the
other pallet z" is in the path of one of the teeth of
the wheel M, and receives an impulse therefrom
which brings it into the front; whereupon the pallet
e' is again placed in such a position as to engage with
the teeth of the wheel and is pushed into the front,
and so on. To prevent the balance being carried
round too far, two pins 1, 2, are placed upon it, and
as soon as the vibration amounts to 120° they strike
against a fixed tongue s, and are prevented from
going any further. This is called ban/ring the
balance.
In the case before us the escapement is formed by
the scape-wheel M and the two pallets z' z' ’ ; and it is
called a vertical recoil eseepement, because each time
that one of the pallets strikes one of the teeth of
the wheel, the balance, which has not yet lost all its
motion, causes the wheel to start back or recoil a
small space. By employing the balance and the
recoil escapement, the movement is not regulated in
a manner altogether satisfactory. Each oscillation
of the balance is communicated by the action of one
of the teeth of the scape-wheel upon one of the
pallets, and this motion is performed with greater or
less rapidity, according as the pressure of the tooth
upon the pallet is more or less intense.
before us, the force of the main-spring is constantly
varying, as is always the case where no fusee is
employed; the friction of the different pieces upon
each other is also liable to variation, especially from
the thickening of the oils used to lubricate them;
these and other causes prevent the pallets from
receiving the same impulse at different times, so
that the successive oscillations of the balance are
not of the same duration.
Fig. 1162 will also enable us to un-
derstand how the train of wheel-work
causes the motion of the hour and
minute hands upon the dial-plate.
The axis of the wheel E is prolonged,
and at its extremity is attached the
minute hand. It is necessary, there-
fore, that the main-spring and the re-
gulator be so arranged that this axis 8
shall perform a complete revolution . in an hour. On this axis is mounted
a pinion P, which engages with a
wheel Q, and the axis of the wheel Q carries a pinion I
In the case'

Fig. 1162.
the minute hand, and it is at the extremity of this
hollow cylinder that the hour hand is fixed. In this
way the two hands may have a circular motion round
the same centre, and yet be moved at very different
rates. The pinion i? has 8 teeth, and the wheel Q
24: 5 the minute hand, therefore, makes 3 turns, while
the wheel Q makes but 1. On the other hand, the
pinion n has 8 teeth, and the wheel 5 32, so that the
wheel Q, makes 4 turns while the wheel s makes but
1; the wheel s therefore makes 1 turn while the
minute hand makes 12, and, consequently, the hollow
cylinder, which serves as an axis to the wheel 8,
gives to the hour hand its proper rate of motion.
The wheels and pinions, P, Q, E, s, with the hour
and minute hands, are set in motion by the axis of
the Wheel E. Motion is communicated from this
axis to all that part of the mechanism situated im-
mediately below the dial, in such a manner that the
hands can be made to move without turning the
wheel E. For this purpose, instead of a single axis
carrying the wheel E, the pinions D and r, and the
minute hand, two axes are employed, placed end to
end, one of which carries the wheel E and the pinion
1), and the other the pinion r and the minute hand.
One of these two axes is hollow at its extremity, and
the other axis passes into this hollow with some
amount of friction, so that when one of the axes is
made to turn, the other will turn also unless it expe-
riences a resistance capable of overcoming the
friction between the two. When the wheel E turns,
it moves the pinion r, and the hands also, which
present only a feeble resistance 5 but, on setting the
watch to the correct time by turning the minute
hand, the axis of this hand does not in such case
set in motion the axis of the wheel E, on account of
the resistance offered by the whole train with which
it is connected. The minute hand being moved
causes only the wheels and pinions 1?, Q, E, s, to
move with it, while all the other wheels continue
stationary.



PRINCIPLE OF THE "WATCH ILLUSTRATED.
During the going of the watch the spring gradu-
E, which engages with a wheel s. This last wheel ally enlarges its coils, and becomes slack ; it there-
is attached to a hollow cylinder 6, through which fore requires to be wound up after certain intervals,
passes, with slight friction, the axis which carries
for which purpose a key is adapted to the square
28
. HOROLO'GY.
extremity‘ 'r of the axis, to which the interior end of
the spring is attached, and this axis is turned in a
direction contrary to that in which the spring acts
upon the train. If the wheel 0 were fixed to this
axis, it would turn with it during the winding up,
and thus impart to the whole train and to the hands
a retrograde motion. To prevent this inconvenience,
the axis of the main-spring is made to act upon the
wheel 0 only through the medium of the ratchet—
wheel B and a click 0, which is kept in its place by
the pressure of a small spring 0'. By this arrangement
the wheel-c is moved by the axis only when the latter
yields to the impulse of the main-spring ; and when
this axis is turned in a contrary direction, as in
winding up the watch, it carries with it only the
ratchet-wheel B, the teeth of which passing in succes-
sion under the click 0, produces the sound so well
known to every one who has a watch. Hence,
during the winding up, the train of wheels and the
hands remain stationary.
1f the above description of the mechanism of an
ordinary watch is well understood by the reader, he
will have but little difficulty in following out those
variations which distinguish a clock from a watch.
The importance of a pendulum in regulating the
movement of a clock has been already referred to.
The escapement commonly employed for transmitting
an impulse from the train to the pendulum is shown
in Fig. 1163. It is called the cmelzor escapement, and
consists of a piece of metal shaped something like an
anchor, suspended from a horizontal axis, on which it
can freely turn. Fig. 1163 shows the common form
of anchor pallets, in which a tooth a is represented as
having just escaped from the pallet A, and a tooth b
on the opposite sideof the wheel has. dropped on to
the pallet. 13. The pendulumwill-not, "however, stop
here, but will advance-1a little fur'therto the left 5 and
thus‘, the slope of ‘the. pallet B will drive. the tooth la, a
little way back, ‘and; produce the recall. No parti-
cular form is required for such pallets. “ Their
acting faces are generally made flat, but they are
it‘ In“.
.»..
7' I
i, ~
'4 i . J‘
is
5‘
as
& aunt __
fl’
.

Fig; 1163. Fig. 1164.
better convex, as there is then less recoil and less
wearing of the pallets by» the points of the teeth.
Strange as it seems that brass ‘teeth should wear holes

in steel made as'hard'as it can be tempered, it will
always be found that the teeth have worn holes in
these pallets after a few years, and the hole will be
deepest towards the end of the place which the tooth
reaches. It is evident that the tendency to make
this hole will be less if the pallet is convex, than if it
be flat.” The recoil escapement is converted into a
dead escapement,ll Figs. 1163, 11641, “ by making
the slope of each pallet stop at the points A and
B where the teeth fall, and making the rest of the
pallets A1) and BE portions of a circle whose centre
is o, the axis of the pallets. For, in that case,
however far the pendulum may swing, no recoil
can take place. The reason why this escapement
is so much better than the recoil escapement is,
that a variation in the force of the clock train pro-
duces hardly any effect upon the time of oscillation
of the pendulum, though it produces a considerable
effect upon the extent of its oscillation.” Although
we cannot determine the proportion which the in-
crease of the arc bears to that of the force, since
it depends upon the varying friction of the different
parts of the clock, yet they have a tendency always
to correct each other 5 and when even the state of the
clock is such that the arc increases just one-third as
much as the clock-weight is increased, these two
parts of the error will exactly counteract each other;
but it generally happens that as the clock gets dirty
the force and the arc decrease in such a proportion
that the loss of time preponderates. But there is
one case in which the opposite effect takes place, to
the surprise of those who know the common result of
a decrease of arc. Church clocks will often be found
in a few months after they are put up to increase
their are of vibration considerably, and at the same
time to gain. Mr. Denison discovered this increase
of arc to arise chiefly from the decrease of friction on
the dead part of the pallets, owing to the teeth and
pallets polishing themselves more perfectly than had
been done by the maker.
When a clock gains it is’ said to have a + daily
rate of so many seconds, and when it loses, a — rate;
but these signs are the reverse of those which indi-
cate the decrease or increase of the time of an oscilla-
tion. The goodness of a clock is indicated, not by
its rate, but by the variation in its rate.
The effect of the self-polishing of the pallets is only
temporary ; and the general eflect of a decrease of
force and space in a dead escapement is that the
clock gains a little, whereas a common recoil escape-
ment loses considerably as the arc decreases; and
this has led to the adoption of a small recoil in the
place of the dead part of the pallets. This recoil is
given by striking the circle of the dead part of the
pallets, not from the axis of the pallets, but from a
point a little below that axis, in the line of centres of
the pallets and the scape-wheel, which produces a
circle of a higher degree of curvature, and, therefore,
raises the teeth a little after they have dropped on to

(1)_ These two figures and. the description are copied from Mr.
Denison’s valuable treatise on Clock and Watch-making, pub-
lished in Weale’s Rudimentary Series, 1850.
HOROLOGY.
29-
the pallets; and the further the pendulum swings,
the greater is the degree of recoil. This is commonly
called the half-(lead escapement‘.
Another form of dead escapement, much used in
the construction of turret-clocks, is called the‘ piaz-
wizeef escapement; it consists of pins set on the face
of the scape-wheel, instead of teeth on its edge; thev
two pallets, instead of embracing about one-third of
the circumference of the wheel, are put so near toge-
ther as to leave room for only one pin to pass between
them; and the end of one slope is situated just over
the beginning of the other. The pins are half-
cylinders : as the upper part of the cylinder could not
act, the cutting it away allows the pallets to slip
through close above the teeth, so as to waste as little
drop as possible.
An escapement invented by Professor Airy and
named the duplex spring escapement, is intended to
prevent the inequalities of force of the train affecting
the impulse on the pendulum. For this purpose
there are two scape-wheels and two pairs of pallets,
one for the stop and the other for the impulse: the
stop-wheel is the one connected with the train, and
the impulse-wheel rides on the same arbor, and is
connected with the other by a spiral spring. The-
stop-wheel is let go by its pallets, which have no
sloped faces, just before a tooth of the impulse-wheel
would arrive at the slope of its pallets, and so the
tooth is carried down the slope and the impulse given
by the force of the spring only.
Escapements of this kind, in which the impulse is
given to the pendulum by a small separate weight or
spring, independently of the force of the train, are
called remontoz'r escapements, because the clock train
winds or lifts up the maintaining force at every
beat, or at some given number of beats of the pen-
dulum. Or to explain the matter a little more fully:
In this form of escapement the impulses given to
the pendulum are not imparted by the large going-
train of the clock, which is exposed to variations of
force and resistance from varying friction, from
changes in the viscidity of the lubricating oil, from
the effect of wind upon the large hands of the exter-
nal dials (which in the Royal Exchange clock are
each 9 feet in diameter); but the impulses are im-
parted to the pendulum by a. small secondary train,
set in motion by the descent of a ball or weight,
which is itself raised at intervals of 20 seconds, by
the mechanism of the going-train. In some cases
a remorztoz'r spring only is used for the purpose of
setting the escapement in motion, it being itself
wound up at very short intervals by the going-train,
which receives its impulse from the prime mover.
Now, as the velocity of the machine is determined by
the escapement, so by detaching this from the power,
whether a weight or a spring, which is always subject
to some irregularity, a more accurate performance is
ensured.
Fig. 1165 shows the method of connecting the
anchor with the pendulum. The horizontal axis D
to which it is fixed has attached to it a stem 15‘,
which terminates at its lower extremity in a hori-
almost entirely removed, for it is exerted

zontal fork or crutch G. The rod of the pendulum
passes between the limbs of this fork, closely but
not so tightly as to prevent the rod sliding __
within it when required, so that the pen-
dulum cannot vibrate without the anchor
vibrating also. The crutch c and the
fork f are also shown in Fig. 1163.
In the recoil escapement, the weight
is constantly'acting on the regulator so
as to modify its rate of going. In the 31
dead heat, the influence of the weight is '
only in the friction of the teeth of the
scape-wheel in the pallets, (which can be
reduced to a very small quantity,) and
in the impulses which the pallets receive
from the teeth at the moment when they
escape. If in addition to this we con-
sider the isochronism of the pendulum,
when vibrating in small arcs, some idea
may be formed of the great accuracy to
which clocks may be brought as measurers of time.J
The duration of each vibration of the pendulum,
upon which the rate of a clock’s going depends, is
determined by the relation between the minute hand
and the scape-wheel. The times of oscillation of
different pendulums are as the square roots of the
lengths of the pendulums. For example, if we take
three pendulums whose lengths are as the numbers
1, 4, 9; then the times of vibration will be respec-
tively as 1, 2, 3. That is, the pendulum whose
length is 1, makes 2 vibrations to every 1 of that
whose length is 4:, and 3 vibrations to every 1 of that
whose length is 9. For practical purposes this
important law is expressed thus :-—the times of vibra
tion of different pendulums are in the same proportion
as the square roots of the distances of their centres
of oscillation from their axes of suspension. Now in
order to regulate a clock so as to prevent it from
going too fast or too slow, the bob of the pendulum
admits of being screwed up or let down, so as to vary
the distance between the centre of oscillation and the
axis of suspension, or, in other words, to alter the
effective length of the pendulum as required. When
the clock gains, each vibration of the pendulum lasts
too short a time: it is lengthened by letting down
the bob through a small space. When the clock loses,
the bob is raised, the effect of which is to shorten the
effective length of the pendulum, and to cause it to
heat more quickly.
Figs. 1166, 1167, show the arrangement of a clock
which is regulated by a pendulum and an anchor
escapement. The moving power or weight A, acts
from the extremity of a cord, which is wound upon



Fly. 1165.

(1) In order to ascertain how much of the first power of the
clock is wasted in the friction of the train and pulleys, or how
much a. given escapement requires, remove the pallets and fix to
the scape-wheel or its arbor an arm of any convenient length,
and hang small weights to the end of it till the Weight that the
clock will just decidedly lift is found, the am being horizontal.
The arm should have a counter-poise and be as light as possible, so
that its own weight may not enter into the question or add much
to the friction of the scape-wheel pivots.
3O
HOROLOGY.


‘V
t




II,-;\
‘I ill-u
‘ ln 1 !

Fig. 1166. woaxme PARTS on A CLOCK.
the barrel B, which it tends to turn round, and with
it the wheel 0. This wheel 0 engages with a pinion
D, the axis of which carries a second wheel E. The
pinion r engages with the wheel E, and upon the
axis of F is fixed a third wheel G, which in its turn
engages with the pinion H, upon the axis of which is
the fourth wheel 1; ; K engages with L, on the axis of
which is the scape-wheel M. The anchor n N, moving
on an‘ axis 0, encloses the upper part of the scape-
wheel M. The axis 0, Fig.1167,_ carries a rod 8,
whose fork T embraces the pendulum rod U U, of
which V is the bob. The pendulum is suspended by
two pieces of steel spring xx, which bend in one or
other direction, according to the vibration of the
pendulum. “ It is of great importance,” says Mr.
Denison, “that the real point of suspension of the
pendulum, that is, the top of the spring where it
begins to bend, should be kept firmly in the same
place; for if it moves it will increase the time of
vibration, since this is evidently the same thing as if
the fixed or real ‘point of suspension was a little
higher up, or the pendulum so much longer. For
this reason, in the best clocks, the 000/; which carries
the pendulum is a strong piece of brass, or in large
clocks a cast-iron frame, fixed firmly to the wall at
the back of the clock. In order that the pendulum
may hang so that the spring will have no tendency to
twist it as it swings, the top of the spring is pinched
or clipped between two thick pieces of brass or iron
called chops, and firmly screwed there; and these
chops have square ends exactly at right angles to a
line down the middle of the spring. A little way
below the top of the chops and exactly in the middle,
a strong steel pin is put through them and the spring
between them, at right angles to the plane of the
spring, and this pin has shoulders so that its thin

ends beyondthe shoulders’will just drop into two nicks




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Fig. 1167.
or V’s, in the sides of the cock, with
the shoulders resting against the sides.
It is evident that the effect of this will
be, that the weight of the pendulum will
cause the square ends of the chops, and
therefore the top of the spring, to be
horizontal; and so, if the pendulum is
made symmetrically, as of course it ought to be, it
will vibrate in a vertical plane at right angles to the
line which is the top of the spring, without any
tendency to twist. The two V’s should be made
as nearly level as possible, and the clock-frame must
be so placed that the pallet arbor is exactly at right
angles to the plane of motion of the pendulum. If it
is not, the pendulum will slide backwards and for—
wards in the fork by which it is connected with the
pallets. In common clocks, both house and turret
clocks, the cock is fixed to the clock frame, and has
merely a slit in it into which the spring fits, having
a piece of brass riveted on to the top to keep it from
dropping through the sli .” ' '
The length of a pendulum beating seconds is
391393 inches.1 Now, supposing our clock to be
furnished with such a pendulum the seconds hand
would evidently be fixed on the axis a, of the scape-
wheel, Fig. 1167. The scape-wheel has 30 teeth, and
as two vibrations of the pendulum are required in
order that one tooth may occupy the place of its
predecessor, it follows that the seconds hand will make
a complete revolution in 60 seconds, or one minute.
The pinion H, fixed to the axis 6 of the wheel K, is
prolonged to the left of the figure, where it engages


(l) A seconds pendulum in the latitude of London, would by
the effect of its own gravity alone, if unassisted and unopposed,
make 86,400 vibrations in an artificial solar day, or 86,163-09 in a
natural sidereal' day.
nononoer.
31
with’ a wheel 0, fixed to a hollow cylinder which
surrounds the axis of the seconds hand, and carries
the minutes hand. By the side of the wheel 0, and
in the same hollow axis, is a second wheel cl, which
engages with a wheel e: the axis of e carries a pinion
j, which engag es with the wheel g; this wheel 9 is
fixed to a second'hollow axis, which surrounds the
preceding and carries the hour hand.
When the weight A has unwound the cord from
the barrel 3, the rotation of the barrel of course
ceases until the weight has been again raised by
winding the cord again on the barrel. This is done
by turning the barrel in the contrary direction to its
usual motion by means of a key, into which the
square arbor it fits. To prevent the whole train of
wheels and pinions partaking of this retrograde
motion, a ratchet-wheel similiar to that noticed in-
Fig. 1162, is employed here also. This ratchet-wheel
P, Fig. 1166, is fixed to the axis of the barrel 13, and
consequently turns with it in whatever direction it
may move. A click Q, is kept pressing against the
ratchet by means of a spring 1%. The click and the
spring are attached to the great wheel 0, so that
when the barrel B rotates under the action of the
weight A, the great wheel 0 must turn also by the
pressure of the ratchet-wheel and the click; but when
the barrel is turned in the contrary direction, as in
winding up, the teeth of the ratchet-wheel pass
rapidly in succession under the click, and the great
wheel 0 does not rotate.
The advantages of a pendulum as a regulator are
evidently confined to clocks permanently fixed in a
position where the pendulum can swing and the
escapement act undisturbed. In watches and chro-
nometers intended to be carried about, such a regu-
lator has been contrived as shall be uninjured by
alteration in position, and at the same time present
as far as possible the advantages of the pendulum.
The balance described in Fig. 1162 satisfies the first
condition, but not the second. Such a regulator,
deriving all its motion from the coiled spring, yields
to all the variations in this force, and is subject to
other changes as already noticed. But the objections
to such a balance are got rid of by the introduction
of the spiral spring, (another of Hooke’s admirable
inventions,) which enables it to oscillate of itself
independently of the main-spring. It is of the same
form as the main spring, Fig. 1158, but is minute in
size and delicate in structure. Its interior extremity
is attached to the axis of the balance, and its outer ex-
tremity is pinned into a cock set on the frame of the
watch. See Fig. 117' 5. The spiral naturally seeks the
position of equilibrium; for whether the balance be
turned in one direction or the other, the spiral coils
are either distended or compressed, and tend by
virtue of their elasticity to occupy the position of
repose, or that given to them in the process of
hardening and tempering, and thus restore the balance
to its first position. But the moment the spiral has
reassumed its position of equilibrium, the balance,
moving by its acquired velocity, still continues to
turn, causing the spiral to move also until the clas-

ticity of its coils and the momentum of the moving
wheel counterbalance each other, and the balance is
for a moment brought to rest: the action of the
spiral being thus at an end, reaction takes place, the
coils move in a contrary direction swinging round
the balance, the momentum of which strains to the
utmost the spiral spring until it again stops, and
swings the balance back. In this way the balance
is made to oscillate from one side to the other,
resembling to a certain extent the vibrations of a
pendulum. In effect the spiral is to the balance what
the moving weight is to the pendulum. It is also
important to note that the times of oscillation of the
balance are independent of their amplitude, provided
the spiral be properly arranged.
This valuable property of the balance does not,
however, qualify it to act as a regulator without
further aid. The escapement must be formed in
such a way as to remove the balance as much as
possible from the action of the main-spring, which
would cause the times of vibration of the balance to
vary according as the main-spring acted with greater
or- less vigour. For a long time the recoil escape-
ment, or one with pallets such as is shown in Fig. 1162,
was used, and it is still used in common watches.
In this case the part of the mechanism which serves
to regulate the movement is arranged as shown in
the Figure, only that the axis of the balance is
furnished with a spiral spring. The regularity of the
motion thus obtained is very great, but much was
still wanting. The balance was increased in value
by the addition of the spiral; the escapement also
required modification. We will notice the principal
forms of escapement; the effect of which has been
to make watches perform their work with very great
accuracy.
The first is the cylindrical or lioi'izoizlal escapement‘ ;
another invention of Graham’s. The verge, instead
of being provided with two pallets as in the recoil
escapement, is of the form shown at B c, in Fig. 1168,
and shown separately in Fig. 1169. The portion a b
is a hollow half cylinder, which is further reduced by
cutting out the portion 0. The semi-cylindrical portion
situated above 0 has an important ofiice to perform.
The scape-wheel is situated in a plane perpendicular


Fig. 1168.
Fig. 1169.
to the axis of the balance, and its teeth elevated above
its surface engage with the hollow cylinder as shown
in Fig. 1168. Figs. 1170 and 1171 further illustrate
32
HOBOLO GY .
the mode in which the cylinder arrests and allows
to pass the teeth of the wheel. By means of the
oscillations of the balance, the cylinder A rotates first
in one direction and then in the other. A tooth 0
presents its point to the exterior surface of the
cylinder, Fig. 1170, but immediately after this has


Fig. 1170.
taken place, the cylinder turns into the position Fig.
1171, and‘ the tooth o, obeying the action of the
motive force, is now brought into contact with the
interior face of the cylinder; the cylinder then
assuming its first position allows the tooth o to
escape, and arrests the progress of the next tooth by
presenting its exterior surface thereto, and so on.
In this escapement so long as one tooth is arrested
by one of the two faces of the cylinder, the tooth
does not tend in any way to make it move in one
direction or the other, the cylinder oscillating under
the action of the spiral only. Nevertheless, the
friction which it undergoes in arresting the motion
of the teeth, in addition to the other resistances
which oppose the motion of the balance, tends to
diminish the amplitude of its oscillations, and the
watch would soon cease to go, if the main-spring did
not from time to time restore to the balance the
motion which these resistances tend to destroy. On
this account the teeth are formed in such a manner
that at the moment when the tooth c, Fig. 1170,
having glided over the exterior face of the cylinder
begins to escape, its convex form presses on the edge
D, and thus accelerates the motion of the balance.
For a similar reason the other edge, E, of the cylinder
is bevelled so that when the extremity of the tooth
attains this edge it glides over the small oblique face
and gives an impulse to the balance.
The cylindrical escapement bears the same relation
to the balance as the anchor escapement does to the
pendulum. In these two escapements as soon as one
tooth is stopped, either by the cylinder or by the
anchor, it remains completely motionless or deal.
In each escapement the regulator is constantly under
the influence of the moving force, which although
feebly exerted still exists, since the teeth rub upon
the piece which arrests them, and at the moment when
they are set in motion they give an impulse to this
piece. _ In order to get rid of the continual influence
of the main-spring upon the regulator, the elzrorzomeler
movement or delaelzecl escapement has been devised.
It is called clelaelzecl, because the vibrations per-
formed by the balance are nearly detached from the
pressure of the motive'power during the greater part
of its, are of vibration. This escapement is shown
in Fig. 1172, in which e is the scape-wheel, made
either of brass or steel, with the teeth considerably
undercut: p is the steel roller or main-pallet, fixed

on the arbor of the balance: it has an opening in it,
the face of which is much undercut, and a piece of
hard stone, such as a ruby, is set in this opening for
the points of
the teeth to
act upon: l is
a stud, firmly A
fixed to one of I
the plates of
the chronome-
ter; and to
this stud the
detent spring
8 is secured
by a screw:
this spring is made very slender in the part 0, and it
is only by the yielding of this thin part of the detent-
spring that any motion can be given to the detent
for the purpose of unlocking the wheel, so that some
part of this spring may be considered as the centre of
motion of the detent; at 0 is a ruby pin, inserted in the
detent in such a way that the teeth of the wheel may
in succession rest on the pin, in which state the
wheel is said to be locked : by means of a screw the
distance of the ruby pin from the centre of the wheel,
and consequently the strength of the locking, can be
adjusted: to the inner side of the detent is attached
a very delicate spring, called the lifting-spring, which
rests upon, and extends a little beyond, the end of
the detent. Concentric with the main-pallet, and just
above it, is a small lifting-pallet, p. The mode of
action is as follows :--In the position given in the
figure, the lifting-pallet is about to move round with
its face in contact with the lifting-spring, which in
the course of vibration it lifts, and with it the detent,
so as to raise the pin 0 clear of one of the-teeth of
the scape-wheel. By the time the wheel is free from
the ruby pin, the main-pallet has advanced so far as
to be ready to receive an impulse from another tooth,
and before the tooth escapes the lifting-pallet parts
with the spring, and the detent resumes its place on
the head of the screw, in which position the ruby pin
receives the point of another tooth, as soon as the
tooth has escaped from the ruby face of the main-
pallet. The balance having performed this vibration
by the impulse given to the main-pallet, returns by
the force of the balance-spring, and with it the lifting-
pallet, the rounded side of which, pressing against
the lifting-spring, raises it from the detent, and passes
without disturbing the detent, which, is not again
lifted till the balance has completed the present
vibration, and returning for the next again brings the
face of the liftingpallet in contact with the lifting-
spring, which, with the detent, it raises, and the act
of escaping again takes place, the balance making 2
vibrations for every impulse, as in the duplex, which
is next to be described. Thus it will be seen, that at
the moment when one tooth escapes, another tooth
of the same scape-wheel gives an impulse to the
edge of the indentation made in the main pallet,
attached to the axis of the balance: and in this way
the moving power by an almost instantaneous motion


Fig. 1172.
. nonoLoer. I as
restores to the balance the motion ‘which it may have
lost during two oscillations. With this exception it
oscillates independently of the main-spring. Another
great advantage of this escapement is, that it requires
no oil. , .
The duplen watch is so named from its escapement-
whccl having two sets of teeth on its rim; the cogs
2" being placed upright nearer the centre, while the
long teeth a‘ are in the plane of the wheel: hence
arises a double action. a is the balance. A. watch
of this kind
.will con-
tinue for a
long time
without
cleaning, or
requiring a
. fresh appli-
cation of oil. It is, however, of delicate construction,
and if not well .made and put together, it is liable
to stop in the pocket, and is expensive to repair if
injured.
The [ever watch is one of the best forms for ordi-
nary use. It is
so named from
there being a
lever added to
the action ofthe
escape-wheel to
give impulse to
the balance. In
Fig-1174:, e is
the escape
wheel, which
gives motion to the ruby pallets p: Z is the lever
which gives impulse to the balance 6. This form is
strong, not liable to get out of order, and is easily
repaired.
In pendulum clocks the rate of going depends upon
the effectivelength of the pendulum: by screwing
up the bob the clock goes faster ; by letting it down
it goes slower. The regulator of a watch requires
adjustment in a somewhat similar manner. The
duration of the oscillations of a pendulum depends
upon the intensity of the earth’s attraction and upon
the form of the pendulum itself. As the earth’s
attraction is, at the same spot, a constant quantity
beyond our control to alter, any variations in the
oscillations of the pendulum must be made by
altering its form. So also the duration of the oscilla-
tions of a balance depends upon its form and upon
the force of the spiral which sets it in motion; but,
contrary to what happens in the case of the pendulum,
it is in modifying the force of the spiral, and not in
changing the form of the balance, that the duration
is varied. Thus by altering the fixed point of the
spiral spring, the acting part is made longer or
shorter. Thus in 1175, AB 1) is the spiral spring,
or a portion thereof. Its outer end is pinned into
a cock ,set on the frame at A. The pointer oBE
turns on an annular or hollow pivot at o, the hole
being left in its centre for the arbor of the balance,
voL. II.



Fig. 1173.


Fig. 1174.

or the '067'9’8 to go through. At B there are two
small pinshclose together, between which the spring
is passed, and which there-
fore determine the point
from which it begins to ,4: \
bend 5 so that asv the v .1" l ‘
pointer or regulator, one, is moved towardstheright, l,‘ it makes the spring vibrate ' ‘
faster, and to the left,
slower. When the regu;
lator has been. moved to
the right .as far as it will
go, and the watch is still
found to go too slow, the spring must be taken out
and shortened by putting the outer end further through
A, and drawing the inner end further out through the
other cock by which it is pinned to the balance.
Variations in temperature greatly influence the rate
of going of a clock or watch, by causing the pendulum
or the balance to contract or expand. The effect of a
difference of temperature of 25°, or that which usually
occurs between winter and summer, would occasion a
clock furnished with a pendulum having an iron rod,
to gain or lose six seconds in twenty-four hours.
Different methods of compensation have been contrived
to correct this source of error, or, in other words, to
construct such a pendulum, that its centre of oscilla-
tion shall, under every change of temperature, remain
at the same‘ distance from the point of suspension.
In the mercurial pendulum aheady noticed, the bob or
weight consists of a jar of mercury so adjusted, that
in proportion as the pendulum rod becomes longer,
the mercury ascends in the jar, and vice verse”, by


which means the centre of oscillation is always kept,
at the same distance from the point of suspension.
Inthe gridiron pendulum parallel brass and steel rods
are used, and the compensation is produced by the
greater expansion of the brass rods, which raise the
bob upwards towards the point of suspension as much
as the steel rods elongate it downwards.1
In the chronometer the compensation is effected by
means of an expansive oalanee, two forms of which,
one with weights, and the other with screws, are
shown in Figs. 1176, 1177. The making and finish-
ing of a balance of this kind is one of the most difficult
tasks which the mechanic has to perform. It is thus
described: A circular piece of steel,of the thickness of
the intended balance, is turned perfectly true, with a
small hole. in the centre, in which. its arbor or axis is
afterwards secured, and upon which it is ultimately
poised. The piece of steel is then put into a melting-
pot, and sometimes secured to it by a pin through a
hole in the centre, with a quantity of fine brass, suffi-
cient, when melted, to cover the steel. After a
gradual cooling, the superfluous brass is filed away
from each side of the flat piece ‘of steel, so that the
steel is completely cleared of brass everywhere except

i (1) In Captain Kater’s Chapter on the Pendulum, appended to
the Treatise on Mechanics in “ Lardner’s Cyclop'wdia,” such in
structions are given as will enable an artist or an amateur to make
a compensation pendulum.
D
84
HOROLOGY.
on the edge. If the juncture of the ring of brass to § to compensate for the effect produced by the increased
: or diminished elasticity of the spring, and conse-
l quently theweights- must be set nearer to the move-
the steel which it now encircles be perfect, the brass
is filed upon its outer edge so as to form a ring of
tolerably equal thickness all round, but double the
thickness required. It is next carefully and equally :
condensed the hammer or burnisher; the steel is ;
then turned'poiit of the centre, and the brass from the .
outer edge, leaving a compound ring perfectly true, =
~ of the proper thickness for the balance, the brass
portion being about twice the thickness of the steel. .
Within the steel trim, a bottom is left, out of- which '
the bar A :c is‘ out. When the balance is ready for
adjustment, the compound rim is cut through on
opposite sides, me, so that each arm may present
nearly a semicircle, secured at one end of the bar .
an, and free to move through the rest of its length. I
The weights w w, Fig. 1176, are turned ‘out of a
piece of brass, with a groove equal in depth to the
thickness of the balance, and of sufficient breadth to


Fig. 1176.
allow the ‘brassyto move round on the balance with a
slight pressure. Each weight is secured in its place
by a small SCI‘B’W passing through the outer edge, and ?
tached.
pressing against the rim of the balance. Two screws,
e 0, called meantime screws, are used for altering the
'rate of the time-keeper, and have nothing to do with
the compensation‘.
This spring acts in the following manner: an in-
crease of temperature diminishes the elastic force of
the balance spring, ‘which would cause the machine to
lose; but the same degree of heat expands the outer
brass ring on the rim of the balance more than it does
the inner or steel one, and these not being able to se-
parate, a curvature of the whole arm takes place, which
carries the weight w towards the centre, whereby the
inertia of the balance is so much lessened as to allow
the balance-spring to exert the same influence over the
balance as it had previous to the change of tempe-
rature. A diminution of temperature increases the
elasticity of the spring, which would cause the
machine to gain, but the brass contracting more than
the steel, curves the arm outwards, thereby increasing
the inertia of ‘the balance, and allowing the spring no
more influence over it than it had previous to the
change of temperature. The proper situations of the
weightsv w w are ‘found by experiments on the rate of ‘
the machine. The nearer the weights are to the
movable ends a a of the arms, the greater the space
through‘ which they move by any change of tempe-
rature, and ‘the greater the variation in the inertia of
the balance ;. so that if an increase of temperature
cause the machine.‘ to lose, or a decrease to gain, it
shows that the compensation is not sufiiciently active;

zle. the inertia of the balance is not altered suificiently
able ends are of the arms. If an increased temperature
cause the machine to gain, or a decrease to lose, the
weights must» be ‘moved further from the moveable
ends a a of the arms. .In adjusting these balances
made with screws, it will be seen that the moving in
or out of the screws a 4, will produce a greater effect
than 3 3, and these than 2 2, and so on 5 and that in
the adjustment two opposite screws must always be '
moved in or out the. same quantity. The mean-time
screws 0 o produce no‘ sheet. on the‘ compensation, as
no motion is given to them by the curvature of the
arms. In every balance-spring of sulficient length,
there is a part which is isochronal, or nearly so, and
this length being found, it is not desirable to alter it
in bringing the machine to» time; for. if shortened, the~
long vibrations will be quicker than the short ones,
' and if lengthened, the short vibrations will be quicker
1 than the long ones. To avoid this source of error,
Y the two screws 0 e have been introduced, the drawing
‘ out of which from the centre causes the machine to
lose, and the screwing them in to gain.
Some years ago, Mr. Dent introduced a balance-
spring of glass.
Fig. 1178 shows
one of his com-
pensation bal-
ances, with the
spiral spring at-
The reader will
now understand
the essential dif-
ferences between a clock‘ and a "watch. A clock or
a watch has been defined as a machine consisting of
a train of wheels turned by a weight, a spring, or
any other nearly constant force, and of which the
velocity is regulated by attaching to it a pendulum,
balance, or fly-wheel, which always vibrates or revolves
nearly in the same time‘. And the‘ only distinction
(except the arbitrary one of mere size) between a
clock and a watch is, that a watch will go in any


Fig. 1178.
position, but a clock only in one. A ~chronometer
is a very accurate kind of watch. What is called a
[Joe/set e/zrovzomez‘er resembles a common watch, and is
made to go the same time with once winding up,
namely, 30 hours. Those used for determining the
longitude at sea are larger, having dial-plates 3 to 41
inches in diameter, and are usually made to go from
2 to 8 days with one winding up. In addition to the
hour, minute and seconds circles, there is one which
denotes the time in days that has elapsed since the
last winding up. Each chronometer is well secured
in a brass box, mounted on gimbals, in order that one
uniform position may be preserved, and the whole is
enclosed in a mahogany case. ‘
Where there vertical space at command, aweight
is used as the motive power, and a pendulum as the
regulator. If the clock is to occupy only a small space,
.HOROLOGY. , .35
‘from each other only in the form of escapement.
as in chimney dials, a weight would be very incon-
venient on account of the frequency with which it
must be wound up. In such case a spring is substi-
tuted for the weight, but no fusee is used, since the
regulator is a pendulum, the oscillations of which are
not greatly influenced by the variations in the force of
the spring. A main~spring and a balance, furnished
with a spiral, are always used in watches, which differ
In
old watches the pallet or recoil escapement was used,
as shown in Fig. 1162. Such an escapement required
the intervention of a fusee to render uniform the
action of the main-spring, notwithstanding its varia-
tions in force. In modern watches the use of. the
cylindrical escapement allows the fusee to be dis-
pensed with, and a much thimier and flatter watch is
the result. In chronometers the detached escapement
is used, and the fusee retained.
When a clock is wound up, the bands do not
make a retrograde motion, for the reason already‘
explained, but remain stationary, and begin to move
again when the winding is completed. In the exact
observations of astronomy it is of importance to
prevent the error likely to arise from the stopping
of the clock during the operation of winding up.
By the following contrivance by Huyghens, the
clock can be wound up without stopping it :—-The
pulley A, Fig. 1179, furnished.’ with a notched
groove, is fixed upon the arbor of the
first wheel. H is a similar pulley, pinned _ m ' on the side of the ratchet E, and movable i" '
on a stud fixed in the frame. An endless ' i 5
cord is put over these two pulleys, and
under the pulleys IB and C, which carry
the weights W 20. It is evident that half
of the large weight W is sustained by the

to bear upon A although the. pulley H be
turned so as to raise the weight w. This I _ _.
is what happens at the time of wind-
ing; for, by pulling the cord next 13, the p UP
the Weight w, which still continues to act with half its weight on A, and conse- Fig. 1179.
quently keeps the clock going. The ratchet B. only
turns during the winding, and is prevented by a click
from going back. It is said, however, that this inge-
nious method does not answer very well in practice,
unless a chain be used instead of a cord: for the
pulleys A and H wear the cord so fast as to make a
good deal of dust, which soon renders the clock foul.
The chain is also objectionable on account of its
weight, which sometimes aids and at other times
counteracts the moving power.
When the maintaining-power of a clock or of a
watch is a spring acting directly upon the train with-
out the intervention of a fusee, as in Fig. 1162, the
watch stops during the winding up, as already ex-
plained: but by a simple arrangement the maintain-
ing-power can be kept up during the For
this purpose the main-spring is placed in a barrel,

attached to the great wheel, and it is wound upv by
turning round the axis to which its inner extremity
is attached. It is evident that if this interior axis be
left undisturbed, or it be made to turn so as to coil
the spring round it, the outer extremity of the spring
will constantly act upon the circumference of the
barrel, and will cause the spur-wheel attached to it
to continue its motion. It is in this way that the
main-spring of chimney clocks is arranged, and also in
flat watches, where the cylinder escapement allows
the fusee to be dispensed with. Of course, the axis
to which the spring is attached in the interior must
be provided with a ratchet-wheel, which allows the
winding to take place in one direction only.
When the main-spring acts through the medium of
a fusee, the winding up is performed by turning the
fusee in a direction contrary to that in which it is
accustomed to turn under the action of the main-
spring. In this way the chain, which by the action
of the spring had been dragged from the fusee and
wound upon the barrel, is again Wound upon the
fusee: at the same time the barrel turns under the
tension of the chain, and exerting a pulling force upon
the exterior end of the main-spring, increases the
number of the coils round its axis, and presses them
closer together. In order that the retrograde movel
ment thus given to the fusee during the winding up
may not be transmitted to the whole train, a ratchet-
wheel is provided, through the mediumof which the
fusee acts upon the train. This ratchet-wheel is let
into a cavity of the great wheel, which is furnished
with a catch, by which the motion of the fusee is
transmitted.
To prevent the stopping during the winding up,
Harrison’s going barrel or rate/lei is used in weight
clocks, and the going fusee in watches and spring-
clocks. Fig. 1180
shows the barrel
with its ratchet
and click; but in
this case the click,
a, is not placed on ‘
the great wheel,
but upon another
wheel riding on
the arbor of the
barrel, between
the great wheel
and the barrel
ratchet : this
wheel has also ratchet teeth out upon it, but turned
the opposite way to the barrel ratchet, as shown
at n; and the click, E c, belonging to it, is a long
arm turning on a pivot c in the clock-frame ; and
this second ratchet-wheel is connected with the great
wheel by a spring, s s, one end of which is fixed on
the ratchet-wheel, and the other end presses against
a pin on the great wheel. The action is as follows:
while the clock is going, the weight pulls the barrel
and both ratchets to the left, and the going-ratchet,
by means of the spring, s s, presses the great wheel
in the same direction: and as the clock goes on,

Fig. 1180.
n 2
36
- HOROLOGY.
‘hour-
into a spiral form, and called a mail, may be put upon
one tooth after another’ of ‘the ratchet R slips ‘under
the long click, and this causes the drop, ' which
'may be heard about every 5 minutes in regulators
and good watches.‘ When the weight is taken off the
barrel by winding up, the going-ratchet immediately
flies back a little towards the right, but is stopped‘ as
soon as one of the teeth arrives at the click, and
there it is held ‘: the spring continues to press the
great wheel as, before, with nearly as much force as
when the weight is acting, and so keeps the Wheel in
motion for the short time that the clock is winding
That part of the clock which publishes the hours
to the ear- is nearly as complex‘ as that which indicates
‘the course of time to the eye. If, however, the clock
is required tov strike only one at every hour, all that
is necessary is to put- a pin into either of the wheels
of the ‘dial work that turns in an hour, and a hammer-
tail or lever over it, so that the pin will begin to raise
the hammer about a quarter before the hour, and just
slip from under it when the minute-hand points to the
Instead of the pin, a flat piece of metal, cut
the front of the wheel. The effect of this is to dis-
tribute the. work of raising the lever over the whole
hour with much less friction thanin the former case.
Now, it will be evident, that. as the wheel H, Fig.
1181, bearing the minute-hand M'H, goes round in the
direction of. the arrow once an hour, it will carry
round with it, in the same time,‘ but a contrary
direction, a similar wheel H’ with the same number
of .teeth .engaginginto it. Now. the snail 8 being
attached to this second wheel, and the hammer-tail
at T resting on the 'snail, as shown 'in'the figure, a

Fig.1181. one sruoxr-z E‘VE‘RY noun.
few minutes after a stroke has been made, the snail,
by? gradually. raising the hammer-tail, will remove the
rknob '0'‘. of the hammer from the bell B until another
hour" is just: on the‘ point of completion, when‘ the
.knob is- at its greatestdistalnce from the bell. During
this {time the spiral. spring w-is' being more and more
strained, so that when the snail suddenly releases the

hammer-tail, the spiral- spring causes the knob to
strike suddenly against the bell, and the spring [1
forces it away again, and the point of the hammer-
tail, falling into a position nearest to the centre of
motion of the snail,‘ as shown in the figure, the pro-
cess goes on as before.
‘ The arrangements for striking the hours and quare
ters is complex, and is often referred to technically
as the clock-work, or the clock-part, the going part
which moves the hands being called the watch-work
or the watch-part‘ even in a clock. Fig. 1182 shows
the striking part of a clock in which the maintaining-
power is a weight. The striking part is also moved
by a weight attached to the cord 11, which is coiled
on the cylinder B, and the motion thus imparted to B
is transmitted to the spur-wheel 0 attached to the
same arbor. The wheel 0 engages the pinion D, and
thus gives motion to a second wheel, E, which, acting
on the pinion F, turns a third wheel, G: this trans-
mits .its motion to the pinion H, and consequently to
a fourth wheel, I: I engages with the pinion K, and
thus moves a fifth wheel, L: lastly, L turns the pinion
F M, the axis of which carries a fly, ff’, which regulates
the movement. While this train of wheels is in



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‘ 1182. ‘THE scrnrxme PART.
motion under the action of the maintaining weight,
certain pins, a a, projecting from one of the sides of
the wheel e, successively'raise-the lever 6, which lever
causes the rotation of the axis 0, to which the tail of
the hammer is attached. ‘As soon as one of 1the pins
a a escapes from under the lever b after having raised
it, this lever is forced by the action of a spring into
. HOROLOGY.
37.
its first position, and the hammer k is thus. brought
towards the bell. If the tail of the hammer were rigid,
the hammer would not strike the hell, but being
flexible and elastic, the hammer, by its acquired velo-
city, passes beyond its position of equilibrium and
strikes upon the bell, when it is immediately driven
away again by the elasticity of its tail. Thus it is
evident that the hammer must strike a blow upon the
bell every time that one of the pins :2 a raises the
lever b. .
When the clock is not striking, a pin 0, in the side
of the wheel I, bears upon the extremity la of a lever
p [6, and the train of wheels is thus prevented from
moving. This lever, moving on a point g, is moved
aside by a pin fixed in the wheel on the arbor vof the
minute hand, (corresponding to n, Fig. 1162,) so that
on the completion of each hour, when the clock is to
strike, the pin 0 is thus released, and the train allowed
to act. If the lever g k falls back into its first posi-
tion, the wheel I is stopped after having made a
single revolution: one only of the pins 64 acts upon
the lever 5, and the hammer strikes only once on
the bell. In order that the hammer may strike the
hour as indicated by the hands on the dial, a knife-
edge, it, attached to the lever g Zr, presses upon the
edge of what is called a count-wired, shown by the
dotted line Z. Certain notches or indentations are
made at unequal distances in the edge of Z, which is
called the Zoekz'ng-plate, and as it is attached to the
axis . of the great wheel n, it revolves in the same
time with the striking movement, but with great
slowness, and presents, 'in succession, the different
parts of its edge to the knife-edge Zr. If, at the
moment when the lever g is falls again, the knife-edge
lo enters into a notch, the extremity ll of the lever
stops the pin 2' ; but if the knife-edge is is opposed to
a portion of the wheel Z situated between the notches,
the lever g [2, cannot stop the pin z‘, and the striking
apparatus continues to move until the wheel Z, in
turning, brings round a notch for the edge In to fall
into.
The wheel Z, which moves through only a small
space each time the clock strikes, performs an entire
revolution in 12 hours, at the end of which time the
hours of the same name recur. During this time the
wheel I revolves as many times as the hammer strikes
the ‘bell ; z’. e. v7 8 times if the clock strikes only the
hours,v and 90' times if the hammer strike once for
each half-hour, as is common in French chimney-
clocks.
The principle upon which the count-wheel is con-
structed does not allow of the hands being set back,
and being liable to derangement, and troublesome to
adjust, it has been superseded in English clocks by
the rue/rand snaz'Z, (invented by Tompion, the father
of English clock-making)1 which allow the hands to

(1) Mr. Adam Thomson, in his amusing and instructive little
work on “ Time and Time-keepers,” (1842,) states that Tompion
and Graham were buried in the same grave in the nave of West-
minster Abbey. A slab bore the following inscription :-—“ Here
lies ye body of Thomas Tompion, who died November 20th, 1713,
aged 75. Also Geo. Graham, Watchmaker and RR. S. whose
curious inventions do honour to ye British genius, whose accu

be set backwards or forwards as required. The count-
wheel is still used in the best French clocks and in
cheap wooden clocks.
Fig. 11832 will enable usto explain the striking and
rqaeni‘z'ng work of an eightsdays clock. In a com-
panionfigure, which we have not copied, are shown
certain wheels, 1? Q R, .with their respective pinions,
which constitute the movement of the striking part,
and the fan s regulates the velocity with which they
move. The wheel 12 has 8 pins, which lift the cross-
piecet of the arbor r 8 times in each revolution of the
wheel P: these elevations of the piece t occasion so
many revolutions of the arbor (I), which arbor has its
pivot projecting to v behind the frame, and carrying on
its squared projection the hammer V. The hammer is
consequently raised every time a pin of wheel r moves
the piece t ; w is a long and strong spring, called the
lznmmer-taz'Z-sprz'ng, attached to the back plate of the
frame, and pressing with its upper extremity under
the cross pin, passing through a hole in the arbor T,
near the face of the back plate; so that when the.
hammer is raised at any time, the spring w urges it
back again with a smart bZow, and makes it strike the
bell behind the frame ; but to prevent the blow being-
too ‘strong, a counter spring, u, is fixed to the conti-
guous pillar, which breaks the violence of the blow,
and makes the hammer return smartly to its place
when the blow is made; this spring U also serves as
a guard, in case a stroke of the hammer should be
made when the bell is taken off. 4 I -
In the centre of the figure is the arbor of the
centre wheel, the end of which is seen within, at the
projecting end of the squared part of the tube, or
cannon, and is called the cannon-pinion} the tube
of this portion is put tight on the arbor of the
hour or centre-wheel, ‘and has a spring placed on
the hour-wheel arbor, pressing its posterior surface
so as to force it forwards against the cross-pin that
keeps the hands on: this action of the spring coca--
sions so much friction, that although the tube is car-
ried round by the hour-arbor, yet it is capable of
being moved round by its hand placed on the square
end independently of this arbor, for the purpose‘ of
setting the hand to the requisite minute on the dial.
The cannon-pinion has 40 teeth, and impels a similar
pinion, 5/, round also in an hour: this pinion g, called
the pinion of report, has a pinion of 6 on its arbor,
and is pivoted into .the cock. is, so that the small
pinion of .6 also revolves in an hour. This pinion of
6 again impels the wheel z'of 72 teethin 16-2 of an
hour; 2'. e. in 12 hours: this 12-hour wheel has also a

rate performances are ye standard of Mechanic skill. He died
ye 16th of November 1751, in ye 78th year of his age.” Mr. Thom-
son feelingly remarks,‘ “ Watchmakers, the writer among the
number, until prevented by recent restrictions, were in the habit
of making frequent pilgrimages to the sacred spot: from the
inscription and the place they felt proud of their occupation, and
many a secret wish to excel has arisen while silently contemplating
the resting-plane ‘of the two men whose memory they so much
revered.” The slab was removed in 1838, and a small lozenge of
marble with the name “Tompion 1713,” and “ Graham 1751” _
substituted in its place.
(2) This figure is reduced, and the description abridged from
one of the admirable articles on Clock and'Watch-work, in Rees’s
Cyclopsedia.
38
Y 'HOBOLOGY.
tube surrounding the tube of the cannon-pinion, ‘but:
in such a way that a third tube, attached to the bridge '.
x, is interposed between the two tubes of the cannon-
pinion'and 12-hourlwheel: the use of this third fixed ‘
tube is to prevent the friction of two tubes revolving '
in contact with suchdifferent velocities as 1.2 :1. On p
the exterior tube of the 12-hour wheel the hour-hand .
is inserted ; and it is evident that whenever the
minute-hand carriesv the cannon-pinion round, the
pinion of report g‘ also moves the same quantity, and
by means of the small pinion of 6 the wheel 21 must, at
the same time, move ,5 of the same space, and conse-
quently the "Q‘hands are so connected that one cannot
move'without the other, supposing them to be both
fast to their respective tubes; but the hour-hand is
put on the ‘round part of its tube, and kept to it by
mere friction, and therefore may be put to any hour
without carrying the minute—hand round many revo-
lutions, and yet, when once placed right, it preserves
its ‘relative velocity as though it were more firmly
attached to its tube. I is the arbor of the seconds-
han-d, which revolves in a minute, and which measures
the 120th part in its divided small circle on the face
of the clock at so many vibrations of the pendulum,
or at so many half-rounds. To the 12-hour wheelz'
is pinioned fast an indented spiral piece of metal,
called the mail, which also revolves in 12 hours.
Each indentation of the snail subtends an angle of
30°- ($290), so that one ‘indentation, whether near to
the centre of motion or far from it, is exactly the
measure ‘of an hour’s motion of the 12-hour wheel,
The steel piece m a is called a rack from the teeth on
the cross piece 292, the lower cross piece of which is
called the met-tail .- this rack is movable on a pin or
stud at the lower angular point, near which the horse-
shoe spring 0, called the mclc-taz'l spring, presses to
keep a pin on the remote end of this tail, against that
indentation of the snail which happens to be contigul
one to it. On the lever, between m and a, is a bend
to prevent its touching the winding arbor r‘ of the
fusee belonging to the striking part: also at m is a
strong steel pin projecting from the rack. Above the
rack .is a horizontal steel bar, 12 q r, movable on
a stud at 4', which is called the Izaw/e’s-éz'll, from the
bill- or angular piece at (1 that catches the teeth of the
rack. The piece 8, fixed to the protruding pivot of
the‘ wheel (next the pin wheel) near its lower extre-
“mity, and revolving with it, gathers up a tooth of the
rack at each revolution, on which account it is called
the gathering-pallet ,- the catch of the hawk’s-bill
having a contrary slope, gives way in the mean time,
and comes back again. by its own gravity. The pinion
on this pivot driven by the pin-wheel (which has 64:
teeth‘ and 8 pins) hasw8 leaves, and therefore revolves
once every timethat the hammer of the bell is lifted;
but its gathering-pallet takes up a tooth of the rack:
at each revolution of its arbor, consequently a tooth
of the rack is gathered up at every stroke of the
hammer when the striking: part is in motion. The
angular piece, ta 2), movableround an arbor, is called
the warmfagjaieee; its lower end, 2), falls in the way of
a pin in the. small hour-wheel g, and its bent end 2,‘

passes .thrdug‘h '- an aperture, 20, in the front plate
of the frame, in such a position as to come in contact
with a pin on the fly, which is therefore unable to
revolve until this bent piece is lifted away from the
The bent end 5 also lies under the piece 8, so
that when it is lifted away ‘from the pin on the fly it
raises this piece and the hawk’s-bill g. The action of
the difierent parts may be thus explained: Whenever
the hawk’s-bill q is lifted from the teeth of the rack,
the spring 0,- pressing against a pin near its tail,
makes it fall back till it meets with some obstacle
to arrest its motion, which obstacle would be the
pin of the pin-wheel in the front plate, if there
were no other interposed before it had fallen so far
back, but if the snail is in any other position than
that wherein its nearest indentation towards the
centre is contiguous to the pin of the rack-tail, the
tail pin of the rack will fall upon the edge of the
snail before the rack has fallen back to the pin :12, and
all the teeth of the rack will not, in this case, pass
the catch of the hawk’s-bill, but- just so many as
there are indentations or steps counted from the
remote angular point of the snail to the step on which
the tail-pin rests. In the position shown in the
figure the‘ tail-pin is resting on the 6th step of the
snail, which denotes that 6 strokes will be given by


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'Fz'g. 1183., THE s'rnrxme AND nnrnarrse'ranrs.
the hammer, or that 6‘ teeth of the rack‘ are to be
gathered up by as many movements to and fro of the
piece 8: but we see that only5 teeth remain to be.
gathered up of the rack ; hence we know that the clock
has struck 1 out of 6, and is in ‘the act of striking;
the clock will therefore now continue to strike till
the upper end of the gathering-pallet .9 falls on the
projecting pin m of the rack, which will be as soon as
the last tooth of the rack is drawn up to the hawk’s-
bill, in which situation the wheel Q cannot revolve
any further till another hour has elapsed. After
another hour is past, the pin of the wheel y will
again elevate the warning-piece c, the bent end I,‘ of
which will first be raised out of the way of the pin of
HOROLOGY.
39
the pin-wheel, and the fly s will run on a revolution
or two with a whistling noise, i. e. the clock will give
warning : but the end 12 of the hawk’s-bill has not
yet been raised far enough by the pressure of the end
if of the warning-piece to make the catch g clear the
teeth of the rack; therefore the rack cannot yet fall
back: presently, however, the hawk’s-bill is lifted
high enough by the continued motion of this pin:
the rack falls back till its tail-pin rests on step 7
nearer the centre, which has now arrived at the point
of contact, and therefore7 teeth of the rack pass the
catch 9 in the fall of the rack, and the hour of '7 is
now struck before the tail of the gathering-pallet 8
falls again on the pin in of the rack, and stops the
striking; at the same time the‘ bend of the warning-
piece catches the pin of the fly and stops it; and
in this Way any number of hours will be struck by the
hammer on the hell that the snail regulates, which re-
volves once in 12 hours; and if any other cause than
the pin of the hour- wheel g should lift the warning-
piece within the hour, counting from warning to warn
ing, the same number of strokes will be repeated,
though it should be a hundred times or more. To con-
vert this striking mechanism into a repeating mecha-
nism, it is only necessary to place a lever g to revolve
round a stud on the front plate of the frameat the
point 7, with a slender spring 2 over it, to bring it back
to its original situation, when the end placed under the
warning-piece is elevated by depressing the exterior
end, which may be done by pulling down a string
attached to this end, as shown in the figure; and as
often as the string ‘is pulled, so often ‘will the clock
repeat the strokes of the current hour.
armed piece 1, 2, 3, called stri/oe or silent, is differently
made in different clocks. In our figure it is movable
on a socket riveted to the end 3 of one of its arms,
round a stud in the front plate of the frame, and as
the socket has scarcely any shake, the other two ends,
1 and 2, move always in the same plane: at the end
marked 1 is a pin projecting above the upper circum-
ference of the face or dial of the clock, so that it may
be moved ‘to the right or left at pleasure: the end
marked 2 has a slope like a wedge on that side which
is next to the plane of the frame-plate, and the end
of the arbor of the warning-piece projects so far as to
touch the inclined plane : this arbor of the warning-
piece has some shake in the direction of its length
within the frame, and its posterior pivot passes be‘
tween the prongs of a forked spring, which, resting
against the shoulder of the pivot, pushes it close to
the interior side of the front plate of the frame, where
a similar shoulder stops it: when the pin at 7 is
pushed to the right, the wedge of the end 2 pushes
the arbor back, and the end 12 of the warning-piece
being carried with its arbor nearer to the frame than
it otherwise would he, falls in the way of the pin of
the hour-wheel g, and the clock consequently strikes
the hour regulated by the snail; but when the pin at
1 of the strike or silent is pushed to the left, the end
2 is withdrawn from the pivot of the arbor on which
the warning-piece is fast, the spring in the frame
pushes it forward so far that the end 0 of this warning—
_ bell.
The three- 2
_ with as much accuracy as is required at any portion

piece is clear of the pin of the hour-wheel g, which
wheel, therefore, continues to revolve from hour to
hour in a state completely detached from the mecha-
nism of the striking part. In clocks which have no
seconds-hand, there is a hand movable in a small
circle in the dial, which answers the same purpose as
the pin at '7.
The machinery for striking quarters is similar to
that for striking the hours, only there are two ham~
mers instead of one, and an additional set of pins on
the striking—wheel for raising them. For what are
called cling-along quarters 2 bells are used, and the
striking-wheel has 2 sets of pins on its opposite sides,
which raise the 2 hammers alternately. If there are
4: or more bells, the rim of the striking-wheel is spread
out so as to form a e/zirne-bnrrel with pins sticking
out from it like the barrel of a musical-box, and the
hammers, which are all set on one axis, are raised by
these pins.
Alarnnzs. If the pendulum be taken off a clock with
a recoil escapement, it will heat about as quickly as
the bell is struck in an alarum; and the striking in
an alarum takes place in the same way as if a double
hammer were put on the end of the crutch of a recoil
escapement long enough to reach the inside of the
In order to let off the alarum, the letting-off
pin is made movable on the wheel which carries it.
“ If the common letting-0E pin were made movable
' upon the hour-wheel, we might make the clock strike
when the long-hand is at 50 m. instead of 60 m.;
l and in like manner, if we put a letting-off pin for the
alarum on a cap or leg, which fits tightly on to the
socket of the 12-hour wheel, we can make it let off
of the twelve hours we please. The key which carries
the pin, has its socket prolonged forward so as to
carry a small dial or hour-circle under the hour-hand,
which always travels round with it ;; but the key does
not fit so tightly that it cannot be moved by the hand
so as to make a pointer in the hour-hand point to any
time we like on the alarum dial ; and then it will let
off at the time so indicated. There is no occasion for
any stop-ping apparatus beyond a single lifting piece
and a pin in the striking barrel, which rests against
the stop on the lifting piece when it is not raised
high enough to let the alarum go. The string of the
weight is attached to a wheel exactly like a recoil
scapewheel, either of the crown-wheel or the plain "
kind, and when it is let off it runs till it is down. Of
course it must not be wound up until within 12 hours
of the time when it is intended to strike.”
The Wate/zrnan’s Glee/e, or Tell—tale Glee/e. In this
clock there are a number of pins sticking out round
the dial, one for every quarter of an hour, and it is
the duty of the watchman on the premises, where
such a clock is kept, to go to the clock every quarter of
an hour, and push in the proper pin, thereby proving
to the inspector, next morning, that he was vigilant
the night. Each pin admits of being pushed
in during a few minutes only, and if the time be neg-
lected it will be found sticking out, and will show the
exact time when the watchman was negligent. In
410'
HOROLOGY'Z' .
a- 'telll'tale clock in one of the lobbies‘ of the House of
Commons the "face and pins are enclosed behind a‘. _
glass, and ‘outside the clock~case 'is-a handle commué ‘
nicating with 'a' small lever‘ standing over a part of-
the circle'in which the pins move; and as the pins
are carried round in a sort of movable '-dial, the effect
of pulling the handle is to push the pin, which comes
under the‘ lever every quarter of ‘hour. I Inthese
clocks the pins are made to pass overanin'clined plane
some hours after they have been ~pushed1"in,--and in
1.131115 way vare pushed out again. -
In Mr. Denison’s' “ Rudimentary Treatise") will be»
found an interesting chapter on " clocks, to;
gether with an account of the negociations forv the
Great Clock for the New Palace‘v at v‘VVe'stnr'iin'ster;
One of the most remarkable clocks in London‘ is that
at the Royal Exchange, the working parts of which
are represented in the full-page engraving which is to
accompany this article. When Mr. Dent was engaged
by the Gresham Committee to construct’ for the new
Royal Exchange as perfect a clock as the state of the
art allowed, he took the advice of, and submitted the
results of his labours, to Professor Airy, the Astrono-
mer-Royal. In the construction of this clock the
trains are contained within a ‘simple but‘strong cast-
iron framing, in which every strain is so completely
self-contained, that the operation of fixing the clock
is easy, nothing more than a firm and level base being
required for the flaming.- >Hollow iron drums are
used instead of ‘wooden cylinders for the driving!
barrels,- and wire instead of hempen‘ ropes are -em~'
ployed for suspending'the weights. The first of these
improvements‘ ensures a more permanent accuracy of
form, and ‘the use I of '. wire-‘rope allows a smaller cord
to be used, Ythu‘s'preven-ting ' the ‘necessity for over-
laying. In this way'the weight exerts the same force
to turn the barrel,’ which is not‘ the case with a
thicker-rope covering the barrelin .‘Zior Slayers. In
this clock thehands are-driven, and the hammers of
the "striking.v part raised,‘ directly from the axis of the
driving-barrehwithout "the "intervention of wheels. and
pinion‘s. Our-engraving will showthe vrods‘ and bevil-
gear ._.by which this ‘clock indicates vthe hour on‘ the
four-dials of the four external faces Tot-the turret.
The pendulum of this clockis compensated, and the
first stroke of the hour is ‘true to a second. For this
purpose- the lever and hammer. are removed to their
greatest distance'before the time of striking, and the
end ofthe lever cremains delicately poised upon the -
‘ rounded.‘ point of the ‘projecting tooth of the pin-
-whe61‘ until ' ‘the ‘exact time .for striking has arrived,‘
it is vreleased on the instant.
_. ‘j thins.i'descrihed'51—‘jThev centre rod of the pendulum‘
i is (if-$36361’, iandris sufficiently long. to pass completely
The pendulum is
‘the itch ' 01? weight, which, however, is not
attachedlto it. .UPon the bottom of this
mat-shred by turning which the length of the
‘pendulum, may'lbjejihicely . ‘adjusted,’ and upon which
stands; a - llblldw column of, zinc, through which the
‘steel rod passes-freely. . On- the; top-‘cf the‘ zinc column

. f (1,); Pennyflyclopaedia, Supplement, Article 9‘ Huang-yr’; _

a metal cap,~from projecting portions of which de-
‘Scendfz' slender1steel-rods, to the lower ends of which
tlreiweighhwliich is a hollow cylinder of ‘iron, capable
of -' sliding; freely vupon the zinc column, is suspended.
Thus, while both the central steel rod, and the two
- smaller steel‘ rods by which they weight is suspended,
expand ‘downwards upon any increase of. heat, the
position ‘of the'weight reference to the point of
suspension of ‘the pendulum remains nearly ‘the same,
because vthe zinc‘ column, ‘though’ shorter than the
central steel rod, expands to an ‘equal extent upwards,
andconsequently raises the weight just as much as it
is depressed by the lehgthening: of'it'he steel‘ rod. As
the pendulum weighs nearly 4* cwt, the operation of
setting it so that its vibrationscmight' be correct to
within a fraction of a second, was a matter of ex-
treme difiiculty. This was met by a contrivance
suggested .by Mr. Airy: the clock being started at
a very small losing rate, a slender spring, so mounted
as to touch the pendulum slightly, (and thus by
slightly diminishing the amplitude of the arc cause
the clock to gain‘) was brought in- contact with the
pendulum-bob nearlyat the centre of percussion, by
means of a line in the clock-room. By this ‘means
the beats of a large turret-clock maybe brought
to coincide perfectly with J those of a chronometer
by which it is set. . The regulating screw, by
which the length of the pendulum is adjusted,
:is not moved for the correction of small errors
in the rate of going, such being provided for by
the use ‘of small supplementary weights laid upon,
each side 9f ‘the top of the pendulum-bob, which.
Weights may be applied or removed without stopping
the cloc .”. ' _ . _
This clock has a remontoir escapement, and the
pallets are j'ewelled with large sapphires. Mr. Airy’s
construction of the going-fusee is also introduced for
maintaining the clock during the wmding.
ELECTRIC Gnocxs. About the yearlSetO Professor
Wheatstone exhibited in the apartments of the Royal
Society in Somerset House an electromagnetic aloe/a,
the object of which was stated to be to enable a single
clock to indicate ‘exactly the same ‘time .in as many
different places distant from each other as may be re-
quired. _ Thus in an astronomical observatory, every
room may be furnished with .an instrument of simple
construction and at small cost, which shall indicate
the time, and beat dead seconds audibly with the same
precision as the standard astronomical clock with
which. it is connected-;, thereby obviating the necessity
for having several, clocks, andjdiminishing the trouble
of winding up and regulating them separately. In like
manner public ofiices and large establishments, one
good clock serve the purpose of indicating the
precise time in every partof the building where it
may be required, and an accuracy insured which it
would be; difficult to'ff‘iobtahi by independent clocks,
without referring vto the cost. In the clock exhibited,
the parts connected with the maintaining and regu-
power were" dispensed with. It ‘consisted
simply of .Va face,gv,vith its second, minute, and hour
‘ ' hands, and. of :a train of wheels communicating motion
. ‘Ill ‘All; :Illlltdaulllllillllllil’illilll
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HOROLOG .—’ ’
Y WORKING PARTS OF THE CLOCK AT THE ROYAL EXCHANGE, LONDON.
\ltlll
HQROLOGY.
41
' revolution.
from the arbor of the seconds hand to that of the I
hour hand, in the same manner as in‘ an ordinary
clock train. A small electro-magnet was made to act
upon a wheel placed on the seconds arbor, in such a
manner that whenever the temporary magnetism was
either produced or destroyed, the wheel, and conse—
quently the seconds hand, advanced glvth part of its
Thus, by alternately completing and
breaking the electric current every second, the appa-
ratus described would perform all the usual functions
of a perfect clock. The method of connecting this
apparatus with a clock so as exactly to repeat the
movements of its hands was as follows :—-On the axis
which carries the scape-wheel of the primary clock
was fixed a small disk of brass divided on its circum-
ference into 60 equal parts; each alternate division
was then cut out and filled with a piece of wood, so
that the circumference consisted of 30 regular alterna-
tions of wood and metal. An extremely light brass
spring screwed to a block of ivory or hard wood, and
not connected with the metallic parts of the clock,
rested by its free end on the circumference of the disk.
A copper wire attached to the fixed end of the spring
proceeded to one end of the wire of the electro-
magnet ; while another wire, attached to the clock
frame, was continued until it joined the other end of
the wire of the electro-magnet. A constant voltaic
battery of small size was interposed in any part of the
circuit. Hence it will be seen that by this arrange-
ment the circuit is periodically made and brokenin
consequence of the spring resting for one second on
a metal division, and the-next second on a wooden
division. The circuit may be extended to any length,
and any number of electromagnetic clocks may be
brought into sympathetic action with the standard
clock.
Mr. Bain, Mr. Appold, and others, have also pro-
duced various forms of electric clocks, in which the
current from the voltaic or cart/21 battery is made to
supply the place of the spring or weight commonly
used as the maintaining power. In these and other
ingenious applications of electro-magnetism as a
maintaining power to clocks, the attraction and repul-
sion of magnets have been brought to bear directly
on the pendulum, the bob of which is a coil of insu-
lated wire, through which the electric fluid is trans~
mitted at intervals. While the current is being
transmitted, the pendulum is attracted by the magnet
and made to produce an oscillation, during which a
pin, projecting from the pendulum rod, pushes a
sliding bar from off certain conducting surfaces upon
which it rests, and thus breaking contact the electric
coil or bob loses its magnetism, and thus ceases to be
attracted by the permanent magnet, which a moment
before "had deflected it ; it, therefore, falls back into
the vertical, and by its momentum performs the
opposite oscillation: but in doing this, the pin again

- (l) The earth battery, as usually made, consists of a large plate
of zinc, and either a plate of copper or a quantity of coke, buried
at a certain distance asunder in damp earth. The moisture of the
earth acts on this voltaic couple as the exciting fluid, and a feeble
but very constant current is produced by this arrangement.

comes in contact with the sliding bar, and restores it
into the position in which the circuit is completed;
the coil is again electrified and consequently again ,
in a condition to be attracted by the magnet: in
swinging up to it contact is again broken; attrac-
tion again ceases; the pendulum swings back again,
and in this way the pendulum is kept vibrating,
and by its vibrations communicates motion to- the
escape wheel or other contrivance, and thence to the
clock train? .
One of the latest arrangements of the electric clock
is that contrived by Mr. Shepherd, of London, whose
clock was shown on a large scale at the Exhibition.
In applying electricity to produce the vibrations of
the pendulum, the amount of power must be constantly
varying with the variations of the battery, and it is of
course impossible to obtain correct chronometrical
results under such circumstances. Now it occurred
to Mr. Shepherd that if, instead of applying the mag-
netic power directly to the pendulum, it were employed,
on the principle of the remontoir escapement, to bend
a spring to a certain fixed extent during each vibration,
which spring in unbending .should give the necessary
impulse to the pendulum, the pendulum would thus
be independent of variations in the electro-magnet,
the function of which would be simply to bendthe
spring.
The three following figures (the drawings for which
have been kindly supplied to us by Mr. Shepherd)
will enable us to convey a correct idea of this ingenious


um lllfl'l' ‘i
(i
i 'f’
. n l


l .J?‘ "
‘I,’ " hwy,

wag.
» ‘
Fig. 1184.
invention, which, unlike the previous electric clocks,
aims at being itself a perfect time-keeper. It should
be stated that in this arrangement the pendulum, the

(2) In our articles ELECTRIC TELEGRAPH and Erncrno-Mo-
TI‘VE MACHINES a variety of contrivances for producing motion
by electricity, and for closing and interrupting the current, will be
found described. In the article ELECTRO-METALLURGY various
forms of voltaic battery are described.
412
HOROLOGY.
aloe/c 5min Iand the stat/sing part has each its own
separate and distinct system of electro-magnets and
voltaic battery, so that the pendulum may continue
to vibrate although the clock train be at rest, the train
being set in motion by its own electro-magnets under
the regulating influence of the pendulum. The striking
part is also under the control of the pendulum and
the train, although moved by its own electric power.
It is one of the peculiarities of Mr. Shepherd’s clock,
that the pendulum does not depend for its motion, as
in ordinary clocks, upon the clock train, nor does it
constitute the maintaining power, as in Mr. Bain’s
clock. The pendulum may be quite detached from
the other portions of the clock, and may, indeed, be
used for a great number of clocks in simultaneous
action.
Fig. 1184 shows the pendulum Q Q suspended from
a triangular framing and passing through a hole in
the bed plate. Mis a horse-shoe of soft iron each
limb of which is surrounded by a coil of wire, 0 0, one
of the extremities of this compound coil terminating
in the metal bed plate, and the other in the triangular
framing at I, in a slight spring tipped with platinum
and insulated by an ivory mounting. The swinging
of the pendulum to the right completes the circuit,
and converts M into a powerful magnet. The two
ends or poles of this magnet pass through the bed
plate and rise a little way above its surface.- A is an
armature of iron which is attracted down to the poles
of the magnet whenever an elcctriccurrent is circu-
lating in the coils, o o, and is detached therefrom by
a weighted lever LL’ as soon as the current is inter-
rupted. The lever L L’ is attached at right angles to
a short axis, the extremities of which move in two
brackets, so as to raise the lever a little way above the
bed plate: to the extremity of the arm L’ is fixed a
weight, which is better shown at w, Fig. 1185, to
which we will now

“if “T
all j refer, this figure re-
' presenting on a
i ‘9 larger scale similar
_} l parts of Fig. 11841.
E F (In this figure, how-






. L a
“it;
ever, L should be if.)
I, I‘ W
" n E’ is called the
‘ impulse spring, and
' ,1’ Dn'adetem‘ or cate/z
= for holding this
spring when bent
by the action of the
magnet. Now the
action is as follows:
--Supposing the pendulum to have swung to the right
by a force which we will explain presently, it touches
the insulathig spring I ‘and closes the circuit; where~ .
upon In becoming magnetised by the passage of a
current through c c, the armature A is attracted down, 4
the efi'ect of which is to move the weight w up, and
in doing so it will raise the arm‘ n’ of the spring or
right-angled lever En’, which moves upon a centre at
its right angle, and in doing so will lock another right-
angled lever D 1)’, leaving it in the position shown in
Fig. 1185. But by the time the detent is locked, the
pendulum, which we have supposed to have swung
from left to right, falls back into the vertical by the
action of gravity alone, and by its momentum is carried
to the left 3 contact is broken at I; M ceases to be a
magnet; the weight w falls down and raises the
I armature A from the magnet, leaving it’ free to fall
when n is unlocked at 1). Meanwhile the pendulum
goes on swinging to the left, and soon causes the
banking screw 'r to strike against the discharging
pallet 13’ and unlock the detent: the arm or lever thereupon falls down upon the impulse pallet n, and
gives the pendulum its impulse back again from left
to right with a force just sufficient for it to continue
its vibration. Thus it will be seen that the periodical
falling of the spring E E’ gives the impulse to the pen-
dulum from left to right; that the making contact
while the pendulum is at the right has the effect of
restoring the spring 12 n’ to its position preparatory to
another fall; that the swinging of the pendulum to
the left breaks contact, and by raising :0 allows n n’
to make another fall. In this way the action proceeds,
the electro-magnet being used for the sole purpose of
restoring the spring to the position shown in Fig.
1185; it evidently does not matter how much the
magnet M may vary in intensity provided it be not
too weak to pull down the armature A, and it is an
advantage to employ an excess of magnetic power in
machines of this kind.
In order to move the clock train and the hands
HH, Fig. 1186, on the dial plate, there are a pair of
pallets r, taking into the teeth of the escape-wheel
at right angles, to which are fixed two or more bar
magnets 35 B. Immediately under or over each of the


Fig. 1186.
poles of these bar magnets is the pole of an electro-
magnet M M.
alternately to attract and repel the bar-magnets,

These electro-magnets are caused
'HOROLOGY-f—‘HORSE-POWER.
43
thereby imparting an oscillating motion. to the pallets, *
which act in the teeth of the escapewheel E, and
drive it forward ': the motion thus produced is carried 1
through a train of wheels in the usual way. In
producing the electric-currents required, two contact-
springs and two batteries are employed: the contact- ;
springs are mounted on an ivory bracket, one spring '-
on each side of the pendulum-rod, with which their
points make contact close up to the centre ‘of motion,
at the end of the vibrations of the pendulum each 5'
way. The batteries are arranged in connexionwith I
these springs, so that the circuit of each battery shall '
‘ plete at the end of each hour), the detent is drawn
as the pendulum vibrates to the right, it completes ‘
be in a contrary direction to the other. Consequently,
the circuit of one battery; the electricity passing
through the coils of the electro-magnets, they cause
one oscillation of the bar-magnets. On the opposite
vibration of the pendulum, it makes contact with the
opposite spring, the battery in connexion with this
being arranged in a contrary direction to the former;
the electricitypasses through the coils of the electro-
magnets in a contrary direction, causing an opposite
oscillation of the bar-magnets, and consequently of
the pallets, ‘which, operating on the teeth of the
escape-wheel, drive it forward. _
Mr. Shepherd in his paper on this subject, read
before the Society of Arts 26th February, 1851, states,
that this method of using attraction ‘and repulsion
has two advantages. It admits of ~ electro-magnets
being used of such size, that about 2,000 feet of wire
may be wound upon them, whereby‘a great saving in
the batteries is effected. It also insures great
certainty in the action with the smallest possible
power, since the powerappliedto move the pallets is
nearly equal throughout the extent of their motion.
By using two batteries, reversed currents may be
produced with only ‘one spring ‘on each side of the
pendulum, while to reverse the-connexion of one
battery, ,two springs would be§required,_*which would
be more disadvantageous. '
The application of the electromagnetism to the
striking part» isthus efi’ected -.v the‘ escape, or seconds-
wheel is furnished vwith aprojecting pin, which is
thus carried round once in minute. The minute-
wheel, carrying the minute-'handhas a similar pin,
which only completes its circuitonce in the hour;
in consequence ofwhich the two pins are in COIljUJlC-
tion only once in that time, namely, exactly at the
hour. On an arbor in the frame of the clock is fixed
an elastic arm, which is insulated from the arbor by
an ivory bush. This ‘arm carries at its extremity a
small pad or table of platinum, on which, if it be
sufficiently raised, the pin of the escape-wheel rubs
in passing. The arbor also carries a rigid arm in
such a position that the pin in the minute-wheel lifts
it as it passes each hour; but the arm cannot be
raised without the elastic arm, also carried by the
arbor, being lifted, by which the platinum table at its
extremity comes into contact with the pin in the
seconds-wheel,--an occurrence which takes place at the
hour, the hands being properly adjusted to that end.
By so doing, it completes the circuit of a battery,

which has one pole connected with the clock—frame
and the other» with the coils of the electro-magnet.
Now, the only break which exists in this circuit is at
the small platinum pad 5 when, therefore, at the
completion of each hour, the pad and the pin are in
contact, the circuit will be rendered complete. The
magnet is thus rendered active, and by its attraction
draws down the armature. The armature is situated
at one end of a lever, the other end of which carries
a detent, which is ‘received into the notches of the
locking-plate. When the armature is drawn. down (in
other words, when the circuit of the battery is com-
out of the notch, and the locking-plate left free to
revolve. ' The raising of this detent forms a contact
between a wire from another battery and the clock-
frame. This battery actuates a magnet, which works
the actual striking apparatus. The circuit is com—
pleted through the clock-frame and through the
bar-magnets, formerly described as oscillating once
in every second, one end of which as it rises touches
a stud immediately over it, ‘at the end of the other
wire of the battery. This magnet, being therefore
rendered active once in every two seconds, while the
locking-plate is free, alternately attracts and repels
one end of a lever, to which is attached the
hammer; the other end taking into a ratchet and
click arrangement, which allows the striking to con-
tinue as long as the locking-plate is free. '
We have already seenthat the inventor of the electric
clock in 184-0,~proposed by this instrument to publish
the precise time in every part of a large observatory,
or other establishment. By an extension of the idea it
is proposed in 1852 to connect all the railway stations
in the kingdom with a great central clock, placed in
communication with the Greenwich electric clock,
which is so constructed as to transmit time—signals
every hour and half hour throughout the day all over
the kingdom. These signals will be received at the
central telegraph office in London, and be despatched
down the difi'erent lines of railway in succession, one
at one hour and another at the next hour. At one
o’clock no time-signal will be sent, .but at that hour
precisely the electric clock will drop the time-ball at
the Royal Observatory, to ‘enable ships in the river to
adjust their chronometers. ’ Time-balls will also be
erected on the roofs of the telegraph offices. As it is
now becoming customary to set all the clocks in the
kingdom to Greenwich instead of local time, ‘the carry-
ing out of this idea will be of great value. By means
of the electric clock it is also proposed to transmit time
signals from one observatory to another, and thus test
some interesting problems respecting longitude, &c.
HORSE-HAIR. See HAIR. '
HORSE-POWER. A term introduced by Watt, to
enable him to determine what size of steam-engine
should be sent to his customers on their informing
him how many horses they were accustomed to em-
ploy to do the required work. It was found by
experiment that the average force exerted by the _
strongest horses at one of the London breweries was
equal to 33,000 lbs. raised 1 foot high in a minute,
4A:
HORSE-POWERéHYDRATES—HYDROCHLORIG ACID.
I I ('11). The action may be thus explained :—
and this was taken as equivalent-to '1-horse-powerf
Since the time of Watt,’ ‘however, -' the ‘capacity of
cylinder answerable to amiss-power, and the pres-
sure on the piston, have been increased, so that at the
present time a horse-power is‘ a‘v mere conventional
unit for expressing a certain size of cylinder Without
reference ton-the power exerted. See STEAM-ENGINE.
HQSIERY. See Wimvrnc.
HOTQB'L‘AST. . See Inon.
HYDRATES,‘ combinations of water with other
oxides. "For example, when a small quantity of water
is poured‘ upon" lime §' (which is ‘oxide of calcium), a
portion I of p the _"water combines therewith, forming
a bulky white powder, which is hydrate of lime
(GaQ'iHO). In the formation of hydrates the action
is often very irregular, and the temperature is greatly
raised, as in the slaking of lime, the example just
given.v The attraction between the water and the
second body'is often so strong that it cannot be sepa-
rated by the application of heat. The hydrates of
potash, of soda, and of phosphoric acid, are examples
of this 5 so‘ also is oil of vitriol, which is a hydrate of
sulphuric acid. ‘ - p
HYDRAULICS. See HYDnosTA'rIcs and Hxnno-
DYNAMICS; _
HYDRAULIC-PRESS. ' See HYDROSTATICS.
HYDBIODIC ACID. 1 See‘rIonrnn.
HYDBOGELORIC ACID, (H01. 37). . This
important acid belongs to the class of hydrogen acids
or'hydr‘acids, which do'not exist in salts. It has long
been known in ‘ solution in water under the names of
spirit of salt, marine acid, and 'mm'iatz'c acid, (from
mamas, sea-salt.) _ In its pure form it is a gas, which
may‘ beI-forme'd by mixing ‘together one volume of
hydrogen one of chlorine, and exposing the mix-
ture'to theilight of day,when the gases slowly combine,
and produce two volumes of hydrochloric'acid gas;
but-if exposed to the direct rays of the sun, thcgases
combine ‘with an explosion : such also is the case
when an electric spark is passed through the mixture.
Hydrochloric acid gas may however be easily prepared
by heating in a flask, fitted with a cork and a bent
tube, a mixture of common salt and sulphuric acid
diluted with water :1 ‘the gas, which must be collected
over mercury, is colourless ‘; it produces a white cloud
or fume in the air in consequence of its strong aiiinity
for moisture; it has an acid‘ suii'ocating odour, and
can be liquified under a pressure of a0 atmospheres.
Its “density is 1‘269 : it is so soluble in water that at
the temperature of the air that liquid dissolves about
4718 times its bulk of the gas. The solution is power-
fully acid. ' ' , ‘
“The "muriatic' acid of "commerce is prepared by de- .
composing, common ‘salt with‘ sulphuric acid and
receiving the gas in water. The materials employed,
, vand the" products, may bel‘stated in another form :—

Chlorine;
Sodium g.
Chloride of sodiuin{ Hydrochloric acid-
’Water ............... .. . -g;g;:ien \
Sulphuric‘ acid.._............i........>Sulphate of soda.

l‘equivale'nt of chloride of sodium ................. .. 60
1 equiv. of sulphuric acid 40, containing 1 equiv.
of water 9
109
PRODUCTS. ‘
1 equiv. of sulphate of 72
1 equiv. of hydrochloric 37
109
In order to condense the hydrochloric acid, 6 equiva-
lents of water : 54¢ are used, which, added to the
equivalent of acid : 37, give 91 of liquid acid: so
that supposing the operation were conducted without
loss, 60 parts of' common salt will give 72 of sulphate
of soda, and 91 of muriatic‘ acid.
There are several methods of preparing the acid on
a large scale. In places where glass can be had at
moderate cost large glass retorts are used. The salt
is first introduced, and then the acid, in such a way,
by means ofa long funnel, so as not to soil the neck.
The beak of ‘the retort is then introduced into a
large globular ‘receiver 1), Fig. 1187, from which
a ‘ tube passes into a Woulfe’s bottle 141,2 and this










q"!
l y‘.
E l
I, .
I
it lu’

a. i _ [1, all? . v
\r
_Fig. 1187 '


a
Q
i


Fig. 1188.
is connected by a bent tube ‘with a second bottle, the
second with a third, and so on; by which means the
acid may-be obtained "of diii’erent' degrees of purity.
The first bottle, which contains no water, retains the

(2) Woull'e’s ‘apparatus is .more particularly described in the
, article Drsrmitarromvolii.p.497.‘ .
HYDROGEN-:HYDROSTATIOS ,AND HYDRODYNAMIOS.
.415
impure portions of the acid, and the‘ vapour then‘
passes from it into the second, third, and other bottles,
which contain a supply of water for condensing it.
That portion of the vapour which escapes condensa:
tion in the bottles is passed by a tube into a vessel of
water. The condensation is instantaneous, or nearly
so, but as the temperature rises less gas is absorbed;
hence the condensing vessels should be kept cool.
The retorts, 4:, 6, 8, or 10 in number, are arranged
in the vault of a furnace, B o, in two rows, as shown
in Fig. 1188, and are heated by the hot air from
the furnace A, which, by an arrangement of the brick-
work, is made to circulate round the retorts on its
passage to the chimney G, and in order that the
drafts of the two contiguous furnaces may not inter—
fere with each other, the chimney for some way up is
divided by a partition wall.
Muriatic acid is also manufactured on the large
scale by using iron cylinders for the retorts. Alkali
works, in which common salt is decomposed for the
manufacture of carbonate of soda, produce enormous
quantities of muriatic acid as a waste product, and,
passing up the chimney, it may be seen condensed
by the atmospheric moisture hovering over it in the
form of a white cloud, which, wafted away by the
wind, produces. a corrosive rain, which ruins the
vegetation of the surrounding district. Of late years,
however, this acid has been turned to profitable
account. [See SODA]
When the solution of muriatic acid gas is pure, it
is transparent and colourless: when saturated with
the gas it has a sp. gr. of'1'21, and contains about
412 per cent. of real acid. The commercial acid is
impure: it has ayellow colour, and contains sulphuric
acid, chloride of iron, and organic matter. It may
be purified by mixing with water and distilling.
HYDROOYANIO ACID. See Pn'ussIAN BLUE.
HYDROGEN, (from if‘o‘wp, water, and ‘yew/dc), to
produce,) one of‘the ‘constituents of , water. Its
symbol is H, and its atomic or combining number 1.
It may be procured by passing vapour of water
through an iron or porcelain tube, containing, in the
middle part, a quantity‘ of iron turnings heated to
redness by fixing the tube across a furnace. The
oxygen of the vapour of‘ water combines with the iron,
while the hydrogen passesoii' in a permanent form,
and may be collected and examined.
Hydrogen may be abundantly collected by the
action upon each other .of zinc, sulphuric acid, and
water: the oxygen of the water unites with the zinc,
forming oxide of zinc, which is instantly dissolved by
the acid, while the hydrogen of the water is set free
in the gaseous form. ~
Hydrogen, when quite pure, is colourless, tasteless,
and inodorous. It is inflammable, burning when
kindled, with a pale-yellowish ‘flame, giving out much .
heat, but very little light, the result of the combus-
tion being water. It is not soluble in water, and it
has never been liquefied; It is the lightest substance
known, its sp. gr. being between ‘0691 and ‘0695.
Under ordinary pressure and temperature 100 cubic
inches weigh 2'14: grains.
_.joint j, the action is as

Although hydrogen is of first-rate importance in
the economy of nature and in chemical science, it has
but very few applications in the useful arts. Perhaps
its most useful industrial applications are in what is
called autogenous soldering [See SOLDERING], and in
restoring to the metallic state copper turnings which
have become oxydized. For this . purpose they are
heated in a tube, and a stream of hydrogen passed
over them, which combines with ,the, Qxygen and
revives the copper. Hydrogen may also be used for
filling balloons in places where coal-gas isnot to be
had; and it may be employed in conjunction with
spongy platinum in an instantaneous-light apparatus,
Fig. 1189, the construction of which is ingenious. It
consists of a glass vessel A, into which passes the
stem of a glass globe B, fitting ‘air-tight at the neck
of A. B is also furnished ‘with, a‘ tight stopple s.
From the side of A proceeds a short pipe furnished
with a stop-cock c, opposite , the jet of which is
mounted, upon a bent wire,‘a ‘ball of spongy plati-
num. Upon the stem of B a piece of thick zinc tube 2
is fixed by means of a ring of cork e at the bottom.
The vessel A is about 3 parts filled with water acidu-
lated with, sulphuric acid. ' On putting the steminto
the bottle, opening 0,
removing s, and turning
away 19, which may be
done by means of the
follows :—'Hydrogen-gas
will be generated, and
rising to the top of the
vessel A, will pass out
through c, and escape,
taking with it the air
left in the vessel. If 0
be now-closed the hy--
drogen will accumulate
in A,- and by its pressure
force the acid water up
the pipe into the globe
B, gradually uncovering
the‘ zinc until it is left quite dry, when of course
the generation of the hydrogen ceases. = If now
we bring the spongy platinum, round before the
jet c,'and~ open the stop-cock, the hydrogen streaming
upon the finely-divided platinum, the latter will cause
the hydrogen to unite with the oxygen of the air, the
effect of which will be to raise its temperature to red-
ness, and thus to set fire to the jet of gas issuing
from the stop-cock. From this ignited jet a taper or
a match-paper may be lighted. While the gas is
issuing from 0, acid descends from B into A, and gra-
dually covers the zinc: thereby keeping up the sup-
ply of gas ; but on, closing 0 the gas drives the acid
back again into B, and the zinc is again left dry. This
apparatus may be made ornamentalin form, and small
in size.
HYDROMETER. See GBAvIrY, Srscrrrc.
HYDROSTATICS and HYDRODYNAMICS,
form the third and fourth of the great divisions of
the Science of Mechanics. The one, which considers

Fig. use.
46
HYDRO STATIC AND? ’ HYDRGDYNAMIIGS.
the laws of water in a state of rest, isderived from
i58wp, water, and arm-6;, standing. still; and the-other,
which takes account of .the. laws which regulateiwater
in a state'of motion, is fromz'f‘o‘wp, andv‘o‘zivanas, force.
The latter is also termed HYDRAULICS.
The properties of liquids are always modified. by
the action. of two forces; viz..- that of. weight, or the
attraction of‘ gravitation, tovwhich they, common
with matter of all kinds, are subject; and, secondly,
molecular attraction, which.‘ must. act; differently in
liquids and solids, although; we. have no means of
determining in what this difference consists. We can
readily ,forman idea of the distinct action of each of
these forces, for 'we . can imagine a mass of water
ceasing to be heavy without ceasing to be liquid;
such a mass would neither fall nor flow when turned
out of the vessel containing it, and indeed it would
not require for its equilibrium'to be sustained by the
ground, or even by a vessel; and yet such a mass of
weightless fluid would display a number of remarkable
properties, the most important of which would be
equality of pressure in all directions; thatis to say,
the liquid would transmit equally, and in all direc-
tions, any pressure exertedlon its surface. For ex-
ample, let a b a 47 cf; Fig. 1190, be a vessel contain-
ing a liquid supposed to be without weight, and I?
a solid piston, which exactly covers its surface. ‘If
the piston be also without weight, it is clear that. the
liquid experiences no pressure, and that if a hole
were made in the ‘vessel no portion vof the liquid
would flow out. Now, suppose that the piston be
loaded with any given weight, say 100 lbs, it. will
of course tend to sink down into the liquid, and it
would do so unless the liquid itself opposed such
a tendency. Whether ‘the liquid be compressible or
not, the result is the ‘same, for the liquid must either
become annihilated, or it must bear up the weight of
100 lbs. If we divide the liquid into any number of
layers, the uppermost layer, which is in contact with
the piston, and- sustains'it, also sustains the whole of
the weight, and would of course descend unless sup-
ported by the layer immediately beneath, ‘which
receives from the one above it as much pressure as
that one receives from the piston. So also the second
layer presses upon the
third, and in this way
we may go on until we
arrive at the bottom
‘of the. vessel, which
we shall find has to
sustain the pressure
of the 100 lbs. exactly
as if the weight and
yf":_::7:_}:_:_}?€ piston were placed
‘Fig- 1190-‘ there instead of being


transmitted by the liquid. " Now, as this pressure
of 100 lbs. is borne by the whole of the base of' the
vessel, it is evident that one-half of the base sustains
only 501bs, and thatv one-hundredth ‘part ofv the base
‘sustains only 11b. We see,- them'from this illustra-
“tion, 1st, That the pressure is transmitted. by hori—:
zontal surfaces from the top. to‘ 1 the bottom of the

vessel without ‘any loss of - efl'ect; 2d, That the pres-
sureis: equal- at each point; 8d, That it is propor-
tional - to the extent of. the surface under consider-
ation.» > .I . . ‘
Sofar we find "no difference- between a liquid and
a ‘solid, but the-peculiar characteristic of liquids is,
that thesame efiects are produced on the sides of the .
vessel aslonthe base. If a lateral opening be made
in any direction, asqat at, the liquid will spirt out;
and if. theropweningthusmade-be of the same size as
the‘ piston '19-, it-‘will-r'equire a force, equal to 1001bs.,
to prevent the water from, spirting out 5 if this side
opening be only one-hundredth of the area of the
piston, the water maybe kept ,back with the force of
1 lb. If‘ a hole he made in the piston, the liquid, will
spirt upwards, proving. that the piston also ‘sustains
a pressure similar to that on the base and sides of the
vessel. Indeed, this necessarily arises from the prin-
ciple of action and reaction. It will be seen that
liquids transmit ‘equally, and in all directions, the
pressures exerted on any part of them, so that every
surface which they touch receives. (and must return)
a pressure proportioned to its area. Thus, if the area
of the piston P be, as we have. supposed, 100 times
that of the piston 22, it will require a pressure of
100 lbs. on r to balance 11b. on p._ Thus we have
another simple. machine, like those commonly called
MncHANIcAnrowEns. And this hydrostatic power, no
less than the others, depends on the principle of vir-v
tual velocities [See MECHANICS]: for it is evident
that if the piston 19 be pushed in through any given
distance, the piston P, which is 100 times large will
be thrust out only 1,1,0 of that distance, so that what-
ever may be the gain of power, it is procured by an
equivalent loss of motion. Used as a press (Bramah’s
press) thisv machine has ‘some. ‘great advantages over
the wedge or the screw, as its mechanical- efficacy can
evidently be increased to almost any extent without
any proportionate increase of friction or complication
of parts.-
Now it must be evident that thisproperty can be
in no way altered by conferring weight‘ on the liquids
under consideration, except that additional forces
arising from the mutual weight and pressure of the
particles have to be taken into account. Whence it
follows, that order for a liquid to vbe in equilibrium,
two conditions are necessary; first, ejv'ery-pointof its
surface must be perpendicular or normal to the force
which acts upon it; and, secondly, ‘ each individual
particle of the liquid must experience equal pressures
in all directions.‘ ,
With respect tov the first condition of equilibrium,
let us suppose that . the surface is llot perpendicular
to the force which acts upon the liquid» particles; that
this surface follows- the. direction a c d e, Fig. 1191,
while the force acts "in the, direction of the vertical
lines vv. ‘ such case a horizontal layer 6 47 must
be pressed by the "Weight of all the particles above
it .5 . and this pressure being, as we have seen, trans-
mitted laterally, the-molecule- 03, for example, would
be-thrus'tout: by this lateral pressure, since there is
no counterbalancing pressure on the opposite side; it

HYDROSTATIGS D HYDRODYNAIMIOS.
a’?
is thrust aside, and another particle occupies its place,
which, in. its .turn, is also thrust aside until at length
the particles forming the curve a a (Z,
have fallen into the depression 0? e,
and the whole surface has become
horizontal. The same process would
take place with any other portion
of the liquid above the horizontal
surface, and there can be no equili-
brium until there are no more par-
ticles to descend; when such is the
case, they are all ranged in a plane normal to the
force.
From the principle of equal pressures, as well as
from the first condition of equilibrium in liquids,
many important consequences are obtained. For
example, the pressure of water and other liquids upon
a given surface, is
in proportion joint-
ly to the magnitude
of that surface and
to the mean height
of the liquid above
that surface.1 This
truth is readily un-
derstood in the case of a cylindrical vessel, such as
No. 1, in Fig. 1192, but it is not so evident in the
vessels No. 2 and No. 3. All three vessels
contain very unequal quantities of water;
" they differ in every respect except being
of equal height and base; and in each
case the same amount of pressure is ex-
erted on the base without any regard to
the bulk of the water. Hence we may
estimate the pressure of a fluid upon the
base of the containing“ vessel by multi-
plying its height into the area of the base,
and this product by the density of the
fluid. In the vessel No. 2 it will be seen
that the bottom bears only the. column of
fluid denoted by the dotted lines, and
which is exactly equal to the whole fluid
in No. 1. But however paradoxical it
may appear, it is no less true, that the
base of No. 3 bears a pressure exactly
equal to this same weight ofv fluid,
although the whole vessel does not con-
tain so much. i .
Some curious results may be obtained
by the operation of this law. Let ‘a
L vessel, A, Fig. 1193, full of water, have a
slender tube, 13, screwed into it: on
filling the tube with water to a certain
height, the vessel will immediately burst;
and the height of the fluid necessary to
effect this result will be exactly the same,
however large or however small the tube may be; so
that the weight of a single ounce of water, if piled
high enough, may burst the strongest vessel. Suppose
the bore of the tube to be one-twentieth of an inch,




Fig. 1192.



Fig. 11%.

(I) That is, its height above the centre of gravity of the surface.

then whatever. pressure is transmitted through it, an
equal pressure will be borne by every space one~
twentieth of an inch in diameter throughout the
interior of A. Now a square inch contains, about
530 such spaces; so that an ounce of water poured
into such a tube would exert a pressure of 530 02s.,
or 33 lbs., on every square inch of A; a force which
few vessels, except steam-boilers, are made capable of
resisting.
Thus the whole interior surface of a vessel is sub-
ject to an enormous pressure in consequence of the
manner in which liquid pressure is transmitted. . And
not only the interior surface, but the liquid particles
also in-every part of the vessel, are subject to cor-
responding pressures. In the interior of the liquid
mass contained in the vessel shown in Fig. 11941,
let us imagine a layer, Z Z, parallel .to the surface s 5-.
All the particles of this layer are evidently pressed
by the mass of liquid above them; they are, as it
were, under the pressure of a liquid cylinder, s s Z Z.
But it is important to observe that this pressure from
above, downwards, is, by the principle of action and
reaction, exactly equal to that from /-\
below, upwards; ‘and the separate
molecules of this layer Z Z are held 8’ Pei: '
in equilibrium by these equal. and
opposite pressures. Now, in limiting
our attention to a portion only of
this layer, a 6, it will be seen that
the surface a 6 is at once pressed
from above, downwards, by the liquid
column a [Z6 a, and ‘from below, upwards, by‘ a
precisely equal force; so that if a solid were plunged
into the water whose base exactly occupied a [1,
this pressure would act upon the solid from below,
upwards, tending to drive it out of the liquid.
This will be clear from the following experiment-—
A tolerably large glass tube, 5, Fig. 1195, ground flat
at its lower extremity, is closed by means of a glass
plate or valve, 0 22, from the centre of
which proceeds a string up to the
top of the tube. If the surfaces be
tolerably smooth, the valve will close
the tube water-tight on pulling the
string. On lowering the tube thus
closed into the vessel of water,
AB on, the thread can be let go, _
because the valve will be upheld by , _
the upward pressure of the water; and that this pressure is equal to that. ‘ F1'9- 1195-‘
which it would sustain at that depth from a column
of water acting from the surface, downwards, is
proved by pouring water into the tube. As soon as
the interior level approaches the exterior a a, the
glass valve is pressed from above as much as it was
before pressed from below, and it then falls to the
bottom of the vessel by its own weight: or- rather
by the difference between its weight and that of an
equal bulk of water, for it cannot descend without
raising such a quantity of water, just as the heavy
arm of a balance cannot descend without raising the
lighter arm.


Fig. 1194.
48
HYDROSTATIOS AND HYDRODYNAMIGS.
‘the same'height. T
The pressure, then, upon a given surface,’ is the
same, whether it face upwards or downwards; and
may also be proved to be the same in whatever direc-
tion it be turned, provided its centre of gravity
remain at the same depth below the liquid surface 3
for this pressure is equal to the weight of a column
of liquid whose base is the given surface, and Whose
length equals the depth of its centre of gravity.
In water, the pressure on any surface at the depth
of 1 footis‘equalfto nearly half a pound on the square
inch. = At 2 ‘feet depth. it is about-1 lb. At 3 feet :
1%- lb. . Atdzfeet 2 lbs. . At 5 feet '==. 2% lbs. In
a cubical vesselfull of a liquid, the pressure on any
one side is equal to oneehalf the pressure on the base;
for the bottom sustains apressure- equal to the whole
weight, of . the fluid, and the pressure sustained by
each side is equal to the weight of a mass as long
and broad as that surface, and as deep as its centre,
and; consequently, equal to half the contents of the
vessel. : Hence we get the remarkable result that, in
a cubical vessel, a liquid produces a total amount of
pressure 3 times ‘as great as its'own weight; for if
this equal 1, and the pressure upon each of the 4: sides
be equal to half that upon the base, then A X t— = 2
and 2 + 1:: 3. ‘ i
In any surface which sustains the pressure of a
mass of fluid, there is a point called the ceiiire ofpres-
sure, at which thewhole pressure of themass maybe
conceived to act, and to which, if a single sufficient
force were applied,;_the mass of fluid would be sup-
ported, and the surface kept at rest. In :any vertical
surface extending. to the top of the fluid, this point is
at one-third-the' depthof . the fluid from the bottom,
and. at .theimiddle of thebreadth of the surface. The
determination or, thisipoint is of the highest import-
ance in all works-made to.‘ resist. fluid pressure.
When a number of vessels communicate with each
other, whatever be their form or size, the same con-
ditions of equilibrium apply to the fluid contained in
them as‘ to a single vessel. In the first place, the
surfaces of the fluid in the vessels are all level,- and,
secondly, they are all at the same level, provided the
same fluid be used. Thus, on filling the large vessel
‘ A with water, or
mercury, or any
other fluid, it will
exert a pressure on
the side tube, near
the bottom, equal
to the area of the
tube X by the
height, X by the
density of the fluid 5
f - . ~ and on opening the
stop-cock c, this pressure will cause the fluid to
ascend into the. small vessel 13 until it attains the
Samelevel as inn, when equilibrium-will be established,


' ' Fig. 1196. ‘
. because-the waterlinn, as wellv as the water'in B,
pressesrupon-the: same space at c,'and both are of
.- ?If_ of different densities, such as water
and mercury, be made to communicate, the height to
i
‘I
which. they'will rise in the limbs iii‘ a vessel such as
A13, Fig. 1197,will be respectively in the inverse
ratio of their densities. If the bend be A a
first filled with mercury, and water be 18-5 =
< then poured into A,‘ a column of > that
‘ fluid, 136 inches high, will be necessary
. to balance 1 inch of mercury in B, mer-
cury being 13T‘55times denser than water.
It matters not how. unequal in bore may
be the two branches of the. tube: if the
experiment be repeated in such an ap-
paratus as Fig. 1196, the, result will be
the same, whether the mercury be in A
1 or in B; the-whole height of water will
always be 13'6 times that of the higher
\ mercurial level above the lower.
The densities or specific gratuities of difl'erent bodies
, are usually compared with water as a standard, on
l what is sometimes called the principle (y’Ai'c/zimedes,
namely, that when a solid is immersed in a fluid, it
a displaces a quantity of the fluid exactly equal to its
own bulk. If the quantity of fluid thus displaced
be lighter than the solid, the solid will sink in the
fluid; if it be of the same weight, it will rest indif-
ferently in any part of the fluid; if heavier, it will
float in such a manner as to displace only as much
fluid as may. equal its own weir/ti. But confining our
attention to the first case (of a body that sinks), the
body thus. immersed in the fluid apparently loses a
portion of its weight exactly equalto that of the fluid
displaced, as: the following experiment will prove.
A solid cylinder of copper s, Fig. 1198, exactly fitting
into a hollow cylinder, 0 of the same material, are both
suspended from an arm of a balance,'and brought into
equilibrium by
Weights in the
opposite scale—
pan )2. The solid
cylinder is al~'
lowed to dip into
an empty glass.
On filling up this
a glass with water,
so as completely
to immerse the
solid cylinder, the
scale-pan‘r will sink down in con-
sequence of the apparent loss of
weight in the cylinder‘ s. Now, on
filling up the hollow cylinder 0 with
water, the balance is restored. The
fluid "support which is given to s is
-, represented _- by the weight - of ‘the
water in 0 required to restore the equilibrium of the
balance; and as s exactly fits into c, the bulk of
water poured into 0 must be exactly equal to that
displaced by s. And this would be true, whatever
might. be the material of s, whether gold or cork.
If ' it were cork,."it» would appear to lose more than





Fig. 1198.
its whole weight, or .- to acquire, when immersed, a '
levity or upward tendency, which, however, is still
found to be neutralized, and its exact weight restored,
HYDROSTATIGS AND HYDRODYNAMIGS.
49
by filling c. It is scarcely necessary to observe, that
all apparent instances of a tendency the reverse of
gravity, as in smoke, balloons, &c., are only effects
of this kind depending on the pressure of the sur-
rounding fluid, which must be denser than the rising
body. ' '
The method of taking the specific gravities of bodies
is described under GBAvrrY Srncrrrc. When a body
floats on a fluid, it displaces a quantity equal in weir/ill
to itself; when it sin/rs, it displaces a quantity equal
in [Jul/r. Hence the conditions of equilibrium in
floating bodies are two : —1st. That the portion
immersed :‘ the whole bulk : : the density of the solid
:thatv of the-fluid. 2d. That the centre of gravity
of the solid, and that of the fluid displaced, are in the
same vertical line. The equilibrium, however, may
be stable or unstable; and if stable, the body will,
on being disturbed, return to its former position by a
number of oscillations which are isochronous, like
those of the pendulum; and their times depend on
the position of a point. called the melaoenlre, which
has the properties of the point of suspension in pen-
dulums. When the metacentre is lower than the
centre of gravity of the whole body, the equilibrium
is unstable; otherwise it is stable.
The principles which regulate the motions of fluids
constitute the science of Hydrodynamics or Hydraulics.
This subject is one of great complexity, on account of
the facility with which a fluid mass is set in motion
by the disturbance of a few only of its particles; and
the resulting motions are modified, either in their
velocity or in their direction, by so many causes, that
it is diflicult to anticipate or explain the various
phenomena which arise. ' There are, however, in
this science certain fundamental laws which go far to
generalize the phenomena.
The sides of a vessel containing a fluid are subject
to two opposite forces—‘one arising from the hydro-
static pressure of the fluid, tending to burst the
vessel outwards; the other, from the atmospheric
pressure, or that of any other medium surrounding
the vessel, tending to burst the vessel inwards. If an
opening be made in the side or base of the vessel, the
liquid will flow out, provided the interior pressure be
greater than the exterior. In the common trick of
covering a glass quite full of water with a piece of
paper, and inverting the glass without spilling the
water, the atmospheric pressure is greater than that of
the water, and would continue to be so if the glass
were 32 feet in depth. If the mouth of the glass be
small, as in a narrow-necked phial, no paper need be
used, for, on inverting it, the ‘pressure of the air on
the mobile but narrow surface bf the fluid will prevent
it from flowing out without dividing, which its cohesion
prevents it from doing. If the neck be enlarged, the
air, being so much lighter than the water, will force
a passage up through it, and break up the liquid
column. But if an opening be made in the top of
the vessel, the liquid will flow smoothly, as if no air
were present ; for the atmospheric pressure, together
with that of the fluid soil/tin, is opposed to the atmo-
spheric pressure alone wit/tout; and the motion is
VOL. II.

produced by the difference of these pressures, viz.
that of the liquid alone.‘ ‘
In the examples which we are about to consider of
hquids escaping from an orifice, the flow will result
from excess of pressure, and not from the breaking
up of the liquid column. . But, in order that results
may be comparable, it is ‘necessary that the surface
of the liquid in the containing vessel be maintained-
at the same height by some contrivance which shall
add to the vessel the same amount of liquid as flows,
from it. In such case, neglecting all mechanical
obstacles arising from friction and other causes, the
flow of liquids from orifices in vessels obeys the force
of gravitation, and their motion becomes accelerated,
according ‘to the law 'of falling bodies. The ex-
pression of this law, known as Tornicellfs theorem, is,
That particles of fluid, on escaping from an orifice,
possess the same velocity as if they had fallen freely
in cacao from a height equal to that of the fluid
surface above the centre of the orifice.
All bodies falling from the same‘ height in oacuo,
acquire the same velocity; but the flow of liquids
from an orifice does not depend upon their densities,
but only on the depth of the orifice below the level
of the fluid. Mercury and water, for example, flow
with the same velocity when they escape by similar
orifices at the same depth below their levels; for
although the pressure of the mercury is 13% times
greater than that of the water, it has 13% times as
much matter to move. \
The velocities acquired by falling bodies are as the
square roots of the heights; so that in order to pro-
duce atwofold velocity, afourfold height is necessary,
&c.; so also in the escape of liquids from an orifice,
the velocities are as the square roots of the depths of
the orifices below the surface of the fluid ,- so that, if
we wish to double the velocity of discharge from the
same orifice, a fourfold depth is required; to obtain
a threefold velocity, a ninefold pressure is necessary,
and so on. Because, in an equal time, lln'z'co as
much matter has to be moved with llzrz'ce as much
velocity. -
When a vessel with vertical sides is allowed to
empty itself by an orifice in the bottom, the quantities
flowing out in successive equal intervals ‘are as a
diminishing series of odd numbers (as 9, '7, 5, 3, 1),
or as the spaces described in equal intervals by a
falling body, lalren backwards.
In such cases there forms, after a certain time, a
hollow depression on the surface immediately over
the orifice ; this increases until it becomes a cone or
funnel, the centre or lowest point of which is in the
orifice, and the liquid flows in lines directed towards
this centre.1L Of course, the issuing stream or vein
is vertical if the orifice is at the bottom of the vessel,
or it describes a parabolic curve if the orifice is at the
side. In either case it moulds‘ itself, as it were, to
(I) In this state of the liquid a rotary motion is'imparted to it,
and rapidly increases, because all the particles‘ are approaching the
centre; and by virtue of their inertia they tend to maintain the
same velocity which theyhad in a larger circle, so that their
angular velocity (or the number of revolutions in a given time) is
constantly increased. > r
E
50
HYDROSTATIOS' AND HYDROLDYNAMICS.
the form of the orifice, and extends to a considerable
distance before it scatters and divides into drops.
Between the mouth of the orifice and the point where
it begins to divide, the liquid vein has a permanent
form, and a polished surface; and notwithstanding
the rapid motion of the liquid particles which succeed
each other incessantly, the jet has the appearance of
a perfectly motionless rod of glass. At the com-
mencement of its course, thev vein is of the, same
diameter as the orifice, but for a short distance its
diameter grows less, forming what is called the term
comma, or contracted vein of fluid, Fig. 1199. The
reason for this contraction appears to be, that asthe
liquid particles approach the orifice, they converge to
a point beyond it, so that the liquid column in escap-
ing must necessarily be narrower or more contracted
at the point towards which the motion of the liquid
converges, than it is either before it arrives at that
point, or after it vhas passed it. The greatest con-
traction of this fluid vein is at a distance from the
orifice equal to half its diameter; the diameter of the
contracted portion being to that of the orifice as 5 : '7.
I _ Hence the real discharge of fluid
‘J Hlf is only or about hair of. the
theoretic discharge, or that
which would take place if the
whole orifice transmitted fluid
with the velocity of a body that
had fallen from the surface. It
is evident that only those par-




L ticles which are vertically above
I, the centre of the orifice can de-
scend through it in a straight
‘*1 line. All others coming from
Fig‘ ‘159' the sides of the vessel must
move in lines more or less inclined. Hence the par-
ticles on the outside of the efiiuent stream are re-
tarded, and move more slowly than those in its centre.
Hence also arises the difference between the mean
velociiy of the escape and the velocity due to
gravity.
The division of the vein at a certain distance from
the orifice is not produced only by the presence of
the air; it takes place in vacuo, and is the result of
the acceleration due to gravity. The effect of acceleration is best seen in a stream of treacle, which
tapers downwards, because the flow, or quantity
passing in a given time, must be equal at all points
of the stream, so that wherever the velocity is greater
than at another point, the size, or sectional area, of
the stream must be diminished in the same propor-
tion. In water, however, the cohesion is not of such
a. kind as to admit of this tapering; but each portion,
when it has acquired a certain velocity, tears itself
away from the stream, forming a drop, and leaving
the stream, which has been forcibly elongated, to
contract again, till another drop is detached. Thus
each drop ‘subject during its fall to certain periodic
vibrations,» which it ‘alternately elongates and
contracts-.=~ A series of pulsations, also, occurs at. the
o1ifi’ce,‘tlie‘ number of which is in the direct ratio'of
the rapidity of the current, and in the inverse ratio

of the‘ diameter of the orifice; they are often sufii-i
ciently rapid to produce a distinct musical sound. If
a note in unison with this be played on a musical
instrument at such a distance as to be scarcely
audible, the aerial pulses thus produced have a marked
effect on the vein in shortening the limpid part.
When a tube is added to the orifice, the flow is
accelerated if air be present, but, iii vacuo, no such
acceleration takes place. The most remarkable and
useful result, however, of the experiments on the
flow of water through pipes, is the discovery that it
may be accelerated by merely giving particular forms
to the commencement and termination of the pipe,
without altering its general capacity. A 4-inch pipe,
of any length, may be made to deliver considerably
more water, if its first 3 inches and last yard be
enlarged conically, than if they were cylindrical like
the rest of the pipe.
()ne of the most intricate subjects to which the
laws of motion have yet been applied deductively, is
that of liquid waves. When any portion of a liquid
surface is raised above or depressed below the rest,
we have already seen, Fig. 1191, that it will return to
the general level, but in so doing it acquires a velocity
which necessarily carries it beyond the position of
equilibriuimand thus produces a series of oscillations,
which are communicated in every direction over the
liquid surface, each portion receiving its motion from
that preceding it, and therefore arriving at each phase
of its oscillation a little later than the preceding
portion; whence arises the appearance of a form
travelling along the surface, which form we call a
wave. Each wave contains, at any one moment, par-
ticles in all possible stages of their oscillation, some
rising, some falling, some at the top of their range,
some at the bottom; and the distance from any row
of particles to the next row that are in precisely the
same stage of their oscillation, is called the breadi/z
g" a wave. Now as these oscillations are caused by
the force of gravity, we may expect some analogy
between their laws and those of the pendulum; and
accordingly, when the depth of the liquid is disre-
garded, or considered as unlimited, the wave-breadth
(like the pendulum-length) varies as the square‘ of the
time of oscillation; so that the time which elapses
between the arrival of the crests of two successive
waves at a fixed point, is as the square root of .the
distance between them, or the distance which either
of them travels ‘over in the said time; hence it is
easy to see that their velocity varies inversely as the
square root of their breadth. For instance, if a
certain buoy be observed to rise and fall twice as
often as another, the waves which pass it must be
four times as broad as those which pass the other,
but as they travel over this quadruple distance in
only double the time, they must evidently move with
a double velocity." When the water, however, is so

(1) The velocity of waves that‘ run in the same or the opposite
direction with aship, may be ascertained by means of the log, or
any other floating body, attached to a known length of cord. By
noticing the time that- el'apses between the lifting of this body, and
that of the ship’s stern, by the same wave, and adding or subtract-
ing the way made by the ship during that interval, we find the
HYDROSTATIGS AND HYDRODYNAMICS.
51
shallow that the waves are affected by the form of the
bottom, the simplicity of these results gives place to
an extreme degree of complexity. The use of these
investigations lies in their application to the tides,
which may be regarded as waves of moderate height,
but enormous breadth and velocity, the time of oscil-
lation being half a lunar day, and the velocity some-
times 1,000 miles an hour.
To Hydrodynamics belongs, also, the theory of
such machines for raising water as do not depend on
atmospheric pressure. Such are the waler—screw,
invented by Archimedes, the endless c/zaz'a oj'laclcels,
the waler-ram, the lzydraalz'c bell, &c. This last-
named machine, the use of which has been revived
within a few years, is one of the most efficient of
water elevators, yet the most inexplicable in its
action. In its ancient form it consisted of a number of
hair-ropes, for which a band of flannel, or felt, is now
substituted, passing over two rollers, one at the top,
and the other at the bottom of the well. By means
of the upper roller, it is set in very rapid motion,
when the water adheres to its surface in a layer which
is thicker the more rapidly it moves, and becomes
nearly half an inch thick when the velocity is 1,000
feet per minute. It follows the band to any height,
and is thrown oh’ by centrifugal force, in turning over
the upper roller.
To this science also belongs the application of the
power of streams and waterfalls to useful purposes.
The chief means of effecting this, are, the aaderslwl
wheel, the Overs/wt wheel, the breast wheel, the lzorz'zoa-
lal water-wheel, the hydraulic ear/i726, Barlcer’s mill,
and the Tarlz'ae. The first two are too well known
to require a description, but we may observe, that
the overshot wheel is always the most advantageous
where the height of the fall is sufficient to admit of
its use. The smallest rill may be applied in this
manner, but the undershot wheel requires a con-
siderable body of water. The breast wheel unites, in
some measure, the advantages of both, and is ap-
plicable to falls of a medium height, as it requires
only a fall equal to its radlas, and not to its diameter,
as is the case with the overshot wheel. This wheel
is formed with plain floats, but the water enters at
the level of its axle, and descends round one quadrant
of its circumference, which is enclosed for this purpose
in a sort of box of masonry. The horizontal water-
wheel is used in some parts of France, and is the
most applicable to a small fall, and a small quantity
of water. Its floats are set diagonally, and may
receive the water at one or at several points of its
circumference at once. In the hydraulic engine, the
pressure of a column of water is applied as the motive
power, by means of a piston and cylinder, like those
of the steam-engine. The Turbine, which acts on a

time which the wave takes to travel the length of the cord. In
this way it has been found, that in the open ocean, some waves
travel at the rate of 80 miles an hour; the breadth of such waves
is sometimes a quarter of a mile. The utmost difference of level
is found by measuring how high above the ship’s water-line an
eye must be raised to have an uninterrupted view of the horizon.
No authentic observation of this kind gives more than 25 feet, even
in the greatest storms.

similar principle to that of Barker’s mill, may be
described as a water-wheel with a vertical axis; it
has hitherto been principally used in France, where
it has been brought to great perfection. It is, per-
haps, the least wasteful of all modes of applying the
power of a waterfall. It will be described-more par-
ticularly further 011. -
In all water-wheels it is a constant rule that the
greatest mechanical effect will be produced when the
velocity of the parts driven is just llalf that of the
stream driving them; and this is a most important
principle, applicable also to the sails of windmills and
ships, and the paddles of steamers. It obvious
that the pressure of the wind or water on any of
these bodies diminishes as their velocity approaches
that of the current, so that if it were possible for a
water-wheel to revolve with exactly the velocity of
the stream, there would be no pressure on its floats,
and consequently, no power to drive any other ma-
chinery. On the other hand, the pressure is at a
maximum when the wheel is standing still, but then
having no velocity, it is also powerless. As the power‘
then is proportional to the product of the pressure
and velocity, it is greatest when they have each their
mean value, that is, in the exact medium between
these two stat'es,-—¢esl and molz'oa will» the camera,—
in other words, it is greatest when the velocity is
lzalf that of the current. I
We will conclude this concise statement of the
principles of Hydrostatics and Hydraulics, (for which
theItditor is indebted to his small work on Mechanics,
published in Weale’s Rudimentary Series,) ‘with a
detailed description of those very important machines,
the fiydroslalz'c press and the hydraulic ram.
Hrnnosrxrro or HYDRAULIC Parse—Although
a machine of this kind was proposed by Pascal in
1664, it was not till 1796 that Bramah succeeded in
overcoming certain diiiiculties in its construction,
which will be explained presently. One form of the
press is represented in Fig. 1200, the working parts
'1 C’
,B
. I. t an 211::
"w . f




3-»
“ I:
.. t - , ,,....;~
' ‘wk .~ at "‘ elk»
' Q \_~ msxsxss
I ,1’ i K - x

1 rhea H
1 "“ . \
I l I I l l I i
Fig. 1200.
of which are shown in section Fig. 1201: c
is a massive cylinder, in which the solid piston or
plunger r moves up and down, carrying at the top a
plate A, between which and the top of the press B,
the goods or substances r intended to be pressed are
E 2
52
HYDROSTATICS AND HYDRODYNAMIGS,
placed. - Water is forced into the cylinder '0 by means
of a pump r, of which the long piston r is worked
by a lever upon a point e, and terminating in a handle
H, the piston 1' being further guided in its vertical
“u.
















5 r 1
F" s Z -
l at: .
g ....... ,-"‘l"l, z I.
. ., iii-Inf‘
.» we ' ' Q .4 . : _ A xii-‘w ‘U ——-_'.‘ .___..__l' ."fl
::—_'—--_'-'._li’_\ '3‘
§ "En—Er. ":

~s\\\\\‘\\\\‘\\\ ' \\\\\\\\\..\\\\\-
Fig. 1201.
motion by a ring at c, in which the stem of the piston
9* works. At each up-stroke of the piston, water is
drawn up from a reservoir placed beneath the pump,
and at each down-stroke, it is forced along the tube
'13 into the cylinder 0'. A valve 22 opening upwards
allows water to pass up from the reservoir, but not
to return back again; and another valve v’ opens to
allow the water passage along '1: into 0, but closes
against its motion in the contrary direction.
Now it is evident from what has been already said,
that the power of this machine depends partly on the
proportion of the magnitudes of the two pistons, and
partly on the leverage of the arm 0 11. Suppose the
diameter of the cylinder to be 12 inches, and that of
the piston of the small pump or injector only ‘i‘ of
an inch, then the proportions between the two
surfaces or ends of the pistons, will be as l to 2,304,
so that a force applied to the small piston will be
multiplied 2,30% times. If the small piston or
injector be forced down with a pressure equal to 20
cwt., the piston of the great cylinder will act
with a force equal to 20 X 2,304: = 416,080 cwt.
: 2,304 tons, which enormous power may be applied
either in drawing or pressing in much less time than
the same could be produced by any other means.
Now the difficulty in constructing this press before
the time of Bramah, arose from the leakage of
water from the cylinder 0, which, of course, rendered
the press useless. Bramah overcame this difliculty
by constructing a leathern collar L in such a way,
that thevery tendency of the water to escape, only
caused such collar to fit the more tightly in its place.
To make this collar, a circular disc of leather is
i first cut out; and from this a second disc is removed,
so as to leave a broad flat ring. This is softened by
steeping ina liquid, and then bent and moulded into a
‘V V, ,. _, collar‘of' the form shown in sec-
iiiii-ihiia" tion,Fig.1202,inwhich condition
1 Fir- 12°2- _ is'fitted into a circular cavity L,
Fig. 1201, made for the purpose in the cylinder‘ 0.
The plunger 1? is then put into its place, and it moves
up and down with friction against the interior bend
of the collar. Now it is evident that when the water



is forced into 0, it will insinuate itself into the ‘hollow
concavity of the collar, and being under an enormous
pressure, will press the collar tightly into its place,
and thus form a perfectly tight joint.
The power of this press is only limited by the
strength of the cylinder 0. We have already seen,
that in raising one of the tubes of the Britannia
TubularBridge, the cylinder of one of the enormous
hydrostatic presses used for the purpose, gave way.
[See Burner, vol. i. p. 2418.] It is usual, however,
in order to prevent such an accident, to furnish the
press with a safety‘valve, consisting of a conical plug
pressed down by a weighted lever, as ~ -- e - shown in Fig. 1203. The size of the
weight w, and its distance from the
fulcrum are determined, so that the -
valve shall not yield to the pressure
of the liquid, until such pressure exceed a certain
limit, at which it is desired to work.
The action of the press can be suspended in a
moment by means of the screws, Fig. 1201, the lower
part of which plugs up a channel leading into the
supply cistern. On turning this screw one way, the
water cannot escape, and the water raised by working
the pumpehandle n, Fig. 1200, is employed as power
toi'raise the plunger 1?; but on turning the screw the
other way, the, water flows back into‘ the cistern, the
pressure in o is instantly relieved, and P descends.
A press recently patented by Mr. Wilson, exhibits
a marked novelty in being constructed with two con—
centric rams. These are acted upon alike by the
water, but from the difference of the areas of the two,
the large or outer ram always tends to rise first,
carrying of course the smaller ram with it. Such a
form of press tends much to economise labour in
working substances which may be pressed in a case
or cylinder. The arrangement of parts and mode of
working, will be best understood by the following
description. The two rams A, B, Fig. 1204:, are
exposed to the same working pressure, there being
a hole left in the large ram A, to admit the water to
the small interior ram. The check rod 0, serves to
stop the large ram whenever it has risen to a certain
height, while strong bolts fixed on the top of the
water cylinder (but not shown in the figure) are
placed so as (when pushed in) to prevent the large
ram from rising at all. Leathers of the usual form are
applied to form water-tight joints around this check
rod, and also around both rams. The oil cylinder 1) n
is of stout cast-iron, and is pierced with holes to allow
the escape of the oil from the substance submitted to
pressure within it.
is movable, and is, when in its place, kept down by
the dogs or hinged catches f f, forming the ends of


' the press bars I‘ F. The mode of using this press is
as follows :—The top n, being lifted off by means of
a chain and winch, and the pumps set to work, the
large ram rises as far as the check rod will allow it,
and then the small ram rises alone to near the top of
the oil cylinder- The water is then allowed to escape
slowly, and asthe ‘small ram first, and then the two
rams together, sink, the charge is filled into the cylin-
The top or head of the press it "
HYDROSTATIOS" AND HYDRODYNAMIOSQ
53
der D D, inthe usual portions, divided by iron plates,
and mats, or baskets. When the charge is complete,
the top is put on, and the large ram being held down
by the bolts, a light pressure is given by the small
ram, to compress and consolidate the loose charge.
.I
Fly. 1204. SECTION on DOUBLE HYDROSTATIC PRESS.
The head is again removed, and as the water is
allowed to escape slowly and the ram to fall, the
space left in consequence of this compression is
filled or -“ topped up” by additional charge. Then
all being ready, the head is again put on and secured
by the dogs, which are prevented from springing
back by the ring cc, wedged up behind them, the
large ram is released and the full pressure applied and
maintained as long as necessary. When this is com-
pleted, the pressure is slackened, so as to permit the
removal of the head, and the pumps are again put to
work, so as to raise at first the two rams, and then
the small one alone, and thus lift the spent charge
out of the oil cylinder. - Then the same process of
charging, topping up, and finishing, is gone over
‘ 0win as at first. The advantage in this press arises
from the ‘capability of 6perating upon a large quantity

‘ of material in a. long cylinder of small area, and
therefore under a great pressure, while from the use
of the two rams as described, the loose charge is
rapidly consolidated by a first pressure quickly ap#
plied, and the spent charge, which from the small
area of the oil cylinder could not be dug out, is
readily lifted out ‘by a slow motion, which allows of
its easy removal. For hot-pressing, the oiLcylinder
may either be surrounded by a steam-jacket of iron
plate,- or- the entire‘press may be built into a hot
room, leaving only the top of the oil-cylinder open to
the charging floor above. The oil which flows down
the sides of _ the oil-cylinder, is collected in r a tray
placed beneath it, and conducted by a shoot ‘or
pipe into the proper vessel or reservoir, The bolts
are placed in openings dd at the bottom. of the
oil-cylinder, which openings serve also to give access,
when needed, to the leathers of the two rams. For
some purposes, the large ram might be left without
any hole for the admission of the water to its interior,
from the water-cylinder, and a pipe, sliding in a water-
tight collar, might be made to convey the water
directly from the pumps to the interior of the large
ram. This, then, becomes a cylinder to the small ram,
and the check’ rod and bolts may be dispensed with, as
the water may be made to act on either of the rams
alone, by the adjustment of the cooks in the supply
pipes. Care must obviously be taken in all cases, not
to applytoo great a pressure to the small ram when
rising alone, for fear of breaking the bolts or check
rod of the large ram, or when’ separate pipes are
used, for fear of bursting the large ram, if it’ is at all
raised out of the cylinder.
THE W ATER RAM, or Belier Hg/waalz'qae, invented
‘by Montgolfier, and improved by his son, is one of
the most simple and beautiful of hydraulic machines,
Its object is to raise water without the aid of any,
other force than that produced by the momentum or
moving force of a part of the water that is to be
raised; and the effect is so great, that the machine
appears to act in opposition to the laws of hydro,
static equilibrium, for a moving column of water of
small height is made to overcome and move another
column much higher than itself. .
. The construction and action of the water-ram will
be understood from the accompanying steel engraving,
in which H is a head of water discharging itself into
a pipe 13, along which it flows with a velocity de-
pending on the height of the fall, and it escapes to
waste unless prevented at the orifice c, which admits
of being opened- or shut by a valve, r is a reservoir
of air, which. is connected with the conduit tube B D
by a small cylinder at b a (Z. In the bottom of F is a
circular orifice, to which a small cylindrical support
is adapted, of which the extremity E is furnished with
a valve. '1‘ is supplied with air by a valve 8, and
there is also a space, m a, full of air. a A is an
ascent tube, rising into a cistern at the top of the
house, or to any considerable elevation where a
supply of water is required. The pipe 13 :0, through
which thewater runs, is called the 606@ (_)f fire mm ,-
the pipe GE, the tube of ascension ,- C is the stoppage
54:
HYDROSTATIOS AND HYDRODYNAMICS.
valve; and n the ascension value. These valves are
hollow globes weighing about double the weight of
water which they displace, and over each is a metal
bridle to prevent it from rising too high. The ex-
tremity of the body 0, and the reservoir E, form what
is called the bend of the mm.
The action of the ram is as follows :-—The water
escaping through c with a velocity due to the height
of the fall, forces the ball :0 out of its muzzle, and
raises it to the orifice c, which it immediately stops.
The water thus suddenly arrested in its passage,
would, by its momentum, burst the tube,‘ were it not
for the other valve alwhich is lifted up, and allows
the water to escape into the reservoir r, whereby the
air is compressed, and by its spring, forces water up
the tube A, just as water is forced out of the jet by the
elasticity of the air in the air-chamber of a fire-engine.
[See Finns, vol. i. p. 662.] The ball 6 soon loses
the velocity imparted to it by the stopping of the
orifice C, and descends by its own weight, as does also
the ball D, into their first positions; the water then
runs off again at C, until its velocity is sufiicient to
raise the ball 1), when the orifice is again closed, and
n again opened by the reaction, and thus the effects
are constantly repeated, in times which are sensibly
equal, in the same ram, and with the same current.
in the action of this machine, four distinct periods
may be traced: 1, the water-escapes through the
orifice o, with a velocity due to the fall, and that
orifice is closed; 2, the air in the space m n is com-
pressed; 3, the ascension-valve is opened, the air
in the reservoir compressed, the water rises in the
ascension-tube e, the ascension-valve c is shut, as is
also the valve 1); a, the air compressed in the second
interval reacts, the valve 1) descends from the orifice,
and the water, again acquiring its velocity, again
produces the like effects.
It will be seen from these details, that a very in-
significant pressing column ii Ii’ is capable of raising
a very high ascending column G A, so that a sufiicient
fall of water may be obtained in any running brook
by damming up its upper end to produce the reser-
voir H, and carrying the pipes 13 1) down the channel
of the stream until a sufficient fall is obtained. A
considerable length of descending pipe is desirable to
ensure the action of the machine, otherwise the
water, instead of entering the air-vessel, may be
thrown back into the reservoir. Air is admitted
from time to time into the annular space (/7292, whence
it finds its way into F.
To estimate the value of this or, indeed, of any
hydraulic engine, its produce must be ascertained,
the expense of its erection, and that of keeping it in
repair. In every hydraulic engine, the force expended
is the product of the water as it comes from its
source, multiplied by the height through which it falls
before it acts on the machine ; the produce being the
quantity of water raised in the same time, multiplied
by the height to which it is elevated.
In a ram placed by Montgolfier in his garden, the
fall, which was procured artificially, was 7-;- feet.
The height to which the water was raised, 50 feet;

the diameter of the tubes 2 inches ; the water pended in 4: minutes, was 315 litres, that elevated
30 litres; hence the expense of force employed is
7% X 315 = 2,362; the useful force 50 X 30 = 1,500,
which give the ratio of 100 to 6% as the expense to
the produce. It appears, however, from the mean of
a number of experiments, that the expense will be to
the produce as 100: 57, so that a hydraulic ram
executed with care, and placed in not unfavourable
circumstances, employs usefully, at least, half its
force.
The youngen Montgolfier so far improved upon
this machine, as to make the work performed amount
to about 60 per cent. The alterations introduced by
him, are shown in the second figure of the steel
engraving, in which A is the feed-pipe or body of the
ram; v the stoppage-valve suspended by a stem to a
sort of stirrup; r‘ the air reservoir, enclosing a smaller
reservoir 0, called the nir-inntmss ,- o o’ are the ascen-
sion—valves, and G the tube of ascension. The action
is as follows :-\—The water in A flowing in the direction
of the arrow, soon acquires sufficient velocity to close
the valve v, and to open the valves 0 o’, whereby a
certain quantity of water enters 1i‘, and passes up G.
This impulse or momentum being expended, the valve
V descends, the water overflows, and is carried off by
a pipe 1) ; after which the same phenomena are re—
peated. Now it will be seen, that as soon as the
water rises above the valves 7) 22', air is imprisoned in
the matrass c, and when the force of the water after
shutting v comes to expend itself upon the air-vessel
F, the violence of the shock, which is considerable in
the arrangement shown in the first figure, is in this
case greatly lessened by the interposition of c, which
acts as a sort of air-cushion ; it also causes the valves
to shut with less noise, and prevents the pipe from
undergoing such violent strains. In short, while a
much larger amount of ~work is done, all the opera-
tions take place with so much ease, that the machine
is less shaken and put out of repair than in the
former apparatus. When the force which opens the
valves o o’, and compresses the air in c is expended,
this air expands, and in doing so, assists the retro-
grade motion of the water in the pipe. The air in c,
in expanding, has for a moment a less pressure than
the external air, a circumstance which is turned to use-
ful account in keeping both 0 and r supplied with air,
as will be noticed presently. The valves 0 o’ remain
open so long as the opening pressure exceeds that
which is exerted upon them by the fluids in n. The
air-vessel in also derives advantage from the matrass
o, for as soon as the valves 72 o’ are opened, and water
enters, compressing the air in r‘, the water is not
immediately forced up the tube e, but can accumulate
somewhat in r, and thus act with great effect, for it
is evident that the pressure required to open the
ascension-valves, would be much greater if the whole
column of water c passed suddenly from a state of
rest into one of motion at the moment the valves
were opened,‘ and they wciuld in such case also remain
open a much shorter time.
One of the great defects of the fire-engine, is the






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HYDBDSTATIGS AND HYDRODYNAMIOS. 55
absorption of the air in the air-chamber by the water,
takes place all the more rapidly as the pressure
is great. Now the air in 1? becomes dissolved rapidly
in proportion to the increasing elevation of water in
the ascension-tube: wherefore in order to keep up a
constant supply, a small shifting-valve is added at H,
consisting merely of a tube with a fine capillary bore
left entirely open. At the moment when the water
of, the ram is relieved from pressure, the density of
the air in 0 becomes slightly less than that of the
outer air, as already noticed; consequently a small
portion of air rushes in through the valve with a noise
like the srz'z'filiizg of a person’s nose, whence this kind
of valve is called a sniffing-valve. A portion of the
air thus admitted finds its way through the valve
72 v’ into n, to supply the place of that which is
dissolved, and carried off by the ascending-column.
At every blow of the ram, 2'. 6. every time the valve B
is closed, and the water is under compression, a
small jet of water is darted out of the snifting-valve;
this valve therefore acts as a sort of pulse to the
machine, drawing in air and jetting out water by
regular periodical movements. Indeed the pulsatory
motion of the ram becomes painfully evident where
the column to be raised is considerable. In such
case, the ground over the pipe is shaken at every
blow, and a tremor is felt in every room of the house
against the wall of which the supply-pipe ascends.
By covering this pipe with felt, the evil may be to
a certain extent mitigated, but cannot be entirely
overcome. Indeed this is the great objection to this
otherwise admirable engine.
In the Great Exhibition, a hydraulic ram was
exhibited in action by Messrs. Faston 85 Amos. They
have also one in action in the yard. of their premises
in Castle Street, Trafalgar Square. They state in
their circular, that they have erected upwards of 500
of these machines in different parts of Great Britain
and Ireland. Persons who have ‘small running streams
on their estates, and require water to be raised to the
. tops of their houses, can do so at very moderate cost.
These self-acting water-rams will raise water 30 times
the height of the waterfall by which they are worked.
In giving estimates, the makers require to know :—
1. The number of feet fall that can be obtained at the
spring or brook to work the ram. 2. The perpendicular
height from the lower part of the fall to where the
water is required to be delivered. 3. The distance
horizontally from the spring or brook to the house or
premises where the water is wanted. If the spring
or stream should be small, it is desirable to ascertain
how many gallons fiow per minute.
The mama; or horizontal water-wheel, is practically
unknown in Great Britain, although in extensive use
in France and Germany, and its working results are
so extraordinary, that some account of it may be of
use in this place. . '
In order to understand the principle of the turbine,
we must refer more particularly to Dr. Barker’ 5
mill, shown in plan and elevation, Figs. 1205, 1206.
It consists of an upright pipe or tube, with a funnel-
shaped open top, but closed at the lower end, from

which project two horizontal pipes or arms, closed at
the outer ends and placed opposite to each other
at right angles with the vertical tube. Near the
end of each horizontal pipe, and on one side of it, is a
round hole, the two holes being opposite to each
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other. The upright pipe is mounted upon an axis or
spindle, and is kept full of water, which flows into the
top. The water issuing from the holes on opposite
sides of the horizontal arms, causes the machine to
revolve rapidly on its axis, with a velocity nearly
. equal to that ‘of the affluent water, and with a force
proportionate to the hydrostatic pressure given by
the vertical column, and to the area of the apertures :
for there is no solid surface at the hole on which the
lateral pressure can be exerted, while it acts with its
full force on the opposite side of the arm. This
unbalanced pressure is, according to Bobison, equal to
the weight of a column, having the orifice for its
base, and twice the depth under the surface of the
water in the trunk for its height. This measure of
the height may appear extraordinary, because if the
orifice were shut, the pressure on it is the weight of a
column reaching from the surface. But when it is
open, the water issues with nearly the velocity ac~
quired by falling from the surface, and the quantity of
motion produced, is that of a column of twice this
length moving with this velocity. This is actually
produced by the pressure of the fluid, and must there-
fore be accompanied by an equal reaction. ‘When
the machine, ‘constructed as in Fig. 1206, moves
round, the water which issues descends in the vertical
trunk, and then moving along ,the horizontal arms 7'
partakes of the circular motion. This excites a cen-
trifugal force, which is exerted against the ends of the
arms by the intervention of the fluid. The whole
fluid is subjected to this pressure, increasing for every
section across the arm inthe proportion of its distance
from the axis; and every particle is pressed with the
accumulated centrifugal forces of all the sections that
are nearer to the axis: every section, therefore, sus—
tains an actual pressure proportional to the square of
its distance from the axis. This increases the velocity
of efiiux, and this increases the velocity of revolution;
which mutual co-operation would seem to terminate
in an infinite velocity of both motions. But on the
other hand, this circular motion must be given anew
to every particle of water as it enters the horizontal
56.
HYDRO-STATES AND HYDRODYNAMIGS."
arm. This can only be done by the motion already
in the arm, and at its expense. Thus there must be a
velocity which cannot be overpassed, even by an un-
loaded machine.- But it is also plain, that by making
the horizontal armsvery capacious, the motion of the
water to thev jet may be made very slow, and much of
this diminution of circular motion prevented.
Desaguliers, Euler, John Bernoulli, and De la Cour,
have treated of this machine, and a few years ago
Mr. James Whitelaw, of Paisley, took out a patent
for improvements in it; but the turbine, as used in
France, appears to be the invention of M. Fourney-
ron, and its value consists in its applicability to falls
of water so high or so low that an ordinary water-
wheel cannot be used; and in falls of great height it
requires little or no mill work to produce the requisite 7
speed.
The turbine ‘ in its present form consists of a
horizontal water-wheel, in the centre of which the
water enters; diverging from the centre in every
direction, it enters a number of ' buckets at once, and
escapes at the circumference orexternal periphery of
the wheel. The water acts on the buckets of the re-
volving-wheel, with a pressure proportional to the
vertical column or height of the fall: and it is led
or directed into these buckets. by stationary guide
curves, placed upon and secured to a fixed platform
within the circle of the revolving part of the machine.
The efliux of the water is regulated by a hollow
cylindrical sluice, to which a number of stops, acting
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.Fig. 1207. SECTIONAL ELEVATION 01-‘ TURBINE.
simultaneously between vthe guide curves, are fixed.
this short cylinder or hoop‘ they are all raised
or lowered together, by means of screws communicat-
with a» ‘regulator or governor, so-thait the opening
of? the 'slui'ceaiid stops may be increased or diminished

in. proportion, as ‘the velocity of the wheel may
require to be ‘accelerated or retarded. This cylindri~
cal sluice alone might serve to regulate the efliux of
the water, but the stops serve to steady and support
the guide curves, and prevent tremor.
._ Fig. 1207 is a’sectioniof the turbine, erected in
1837 at St. Blasier, in the Black Forest of Baden, and
Fig. 1208 a quadrant of the same. The body of the
machine is of cast-iron; the water-wheel or revolving
part, is of hammered iron, and the spindle or axis E,
of steel; B is the cylindrical sluice or regulator;




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Fig. 1208.‘ ounnnan'r or TURBINE.—Pla’n-
' w w the stops ; o the fixed platform ; a: a’ the leading
or guide curves which conduct and direct the water
into the buckets yy; 1) is the hollow shaft supporting
the platform 0. The axis of the water-wheels makes
. from 2,200 to 2,300 revolutions per minute, and
drives the machinery of a cotton mill. The arrow
shows the direction of rotation. The foot of the
spindle, and the pivot and step on which it revolves,
are tempered to extreme hardness. The oil pipe at
‘ the foot of the pivot is comlected with a small force-
pump or syringe, which, at regular intervals, injects
a little oil into the step for lubrication; the pump is
worked by a slow motion from the machinery. The
foot of the spindle must be made hollow, and run.
upon a fixed pivot. The spindle must never run in a
hollow step. The pivot should be, quite cylindrical,
and should truly fit the spindle with as‘ little play as
possible; the top of the pivot should be but slightly
convex. Water and mud must be carefully excluded,
and the parts regularly oiled.
This turbine is moved by a fall or column of water
of 72 feet. The wheel is of cast-iron, with wrought--
iron buckets ; it is about 20 inches in diameter, and
weighs about 105 lbs; it is said to be equal to 56
horses’ power, and to give a useful efi'ect equal to
‘.7 0 or 7 5 per cent. of the water power employed. It
is used for driving a spinning mill. A second turbine
at the same'mill is worked by a column‘ of water 354:‘
feet high, which is brought into'the machine by cast»
iron pipes of 161,; inches diameter. The diameter of -
Ion.
57
' 1110136.
' the’ water-wheel is about 13 inches, andis said to
expend a cubic foot of water per second, or probably
The width of the water-wheel across the face
is less than i—inch. It makes from 2,200 to 2,300
revolutions per minute, and on the end of the spindle
or upright shaft of the turbine, is a bevelled pinion of
19 teeth working into 2 wheels on the right and
left, each of which has-300 teeth; these give motion
to the‘ machinery of the factory, and drive 8,000
water spindles, with roving frames, carding“ engines,
cleansers, and other accessories. The useful effect is
reported to" be from 80 to 85 per cent. of the
theoretical water power. The water is filtered at the
reservoir before it enters the conduit pipes, since the
apertures of discharge in the water-wheel are so
small as to be easily obstructed. The water enters
the buckets in the direction of the tangent to the
last element of the guide curves, which is a tangent
to the first element of the curved buckets. The
water ought to press steadily against the curved
buckets, entering them without shock or impulse,
and quitting them without velocity, in order to ob-
tain the greatest useful effect; otherwise a portion of
the power of the water must be wasted or expended
without producing useful effect on the wheel.
The general application of the steam-engine as the
moving power for machinery, has to a great extent
superseded the use of water power in England. But
there are many places, especially in hilly districts,
where high falls of water occur, or where reservoirs
could ‘easily be made, so as to ensure a constant
supply, and where the'height of the column may com-
pensate for the smallness of its volume. In such
situations the high pressure turbine, or that with a
lofty column of water, may be applied with advantage
for grinding corn, working threshing machines,
crushing ore, &c. In other situations, where a great
volume of water rolls with but little fall, with a head
of only 9 inches, the low-pressure turbine has done
good service. .
- In'places where coal is scarce, but water abundant,
there is another engine which may, with advantage,
take the place of the steam-engine. This is the
Reciprocating Water-pressure ‘Engine, a description of
which we propose to give under the head, WATER
Pownn, to which we must also refer for other in-
teresting applications of the principles of Hydraulics
and 'Hydrostatics}
HYGROMETER. See EVAPORATION.
HYPOGAUST. See WARMING AND VENTILA-
Tron.‘
ICE. The command of a proper supply of ice or
snow for cooling water or other liquids in summer
has long been regarded as one of the necessaries of
life. And so ancient is the practice, that we even
find allusions to it in the Proverbs of Solomon ,—

(l) The above notice of the Turbine, is from a report made by
Joseph Glynn, F.R.S. the. to the British Association for the
Advancement of Science. Fourneyron’s Turbine has been im-
proved and varied by M. Callon, by M. Fontaine of Chartres, by
M. Jonval, and by M. M. Koechlin of Mulhausen. These are
described in Delaunay’s beautiful little work, entitled, “ Cours
Elémentaire de Mécanique,” Paris, 1851.

“ As the cold of snow in the time of harvest, so is a
faithful messenger to them that send him; for he re-
fresheth the soul of his masters.” xxv. 13.
Referring to other authorities2 for antiquarian
notices on the art of cooling summer drinks and
sweetmeats, we propose to give a slight sketch of the
modern method of collecting and storing ‘up; ice and
snow, so as to afford a constant supply for summer ;
secoiidly, to state the modes which have been adopted
for' forming ice artifically; and thirdly, the methods
of obtaining low temperatures by the use of what are
called-freezing mialares. ‘.
The most simple and obvious method of securing
a magazine of cold to meet the physical wants of
summer, is to collect, during the winter, a store of
ice or of snow, and to place it under such circumstances
that it shall be shielded from rain, from warm air,
and from the direct rays of the sun. . .
In our article on the preservation of Foop, we
stated how desirable an appendage to markets, 850.,
would be an ice-house, for the purpose of preserving
fish, meat, fruit, and vegetables fresh much longer
than can be done by other means. The simplest
method of keeping ice is by enveloping it in a large
quantity of loose straw. For this purpose, the ground
is formed into a flattened cone, for draining off the
water from any portion of the melted ice; a layer of
faggots is then put therein, with straw a foot or more
in thickness, and on this the ice is piled in a large
conical mass, and covered with straw to the thickness
of one. foot, then with faggot-wood to the thickness
of two feet, for the purpose of preserving a stratum
of air above and around the ice ; and lastly, the whole
is covered with two or- three feet of straw arranged as
a thatch. The ice, thus surrounded with badly con-
ducting materials, may-be kept throughout the year.
Some recommend as the best situation for such an
ice-stack, the shade of trees, or under a shed roof,
closed on the south side, and open on the north.
Others consider the vicinity of trees to be objection-
able, in consequence of their tendency to increase or
prolong the humidity of the air. 80, also, others re-
commend an eastern or south-eastern aspect in pre—
ference to a northern aspect for the ice-house door, in
order that the morning sun may dissipate moisture
from it.
An underground ice—house may consist of a large
cellar, with the walls, floor, roof, and doors hollow,
or double, and with a trapped drain to allow water to
escape without admitting the air. Such ice-houses are
usually in the shape of an inverted cone, which allows
the ice to form into compact masses, in which condi-
tion it retains the solid form far better than when it
is loosely piled, and should any of the ice thaw out,
the slipping down of the remainder will tend to keep
the mass together. But the construction of such an
ice-house as this, is very costly; and according to

(2) The various methods of cooling liquors as practised by the
nations of antiquity and traced to comparatively modern times are
given by Beckmann in an amusing paper in his History of Inven—
tions. See also Professor Leslie’s Treatise on Cold; published in.
the Encyclopaedia Britannica.
58
ICE.
London,1 is not necessary, for “ a plain square room
with double side walls, say a foot apart, a double arch
over, and a double floor under, which can be built
with the same case as any common cellar, will, all
other circumstances being alike favourable, keep the
ice as long as any conical form. whatever.” It is de-
sirable to interpose a layer of straw, reeds, or chaff
between the walls and the ice; and by a proper
arrangement of straw and faggots, an ordinary
cellar, if dry, and well situated, will serve as an ice-
house. In some places, caverns in limestone rocks,
or excavations with a long circuitous passage, by way
of approach, may be used for storing ice.
The only communication between the interior of an
ice-house and the external air should be by means of
the entrance passage, which may be two or three
yards long, and be furnished with three or four doors,
only one of which must be left open at once. A por-
tion of the passage may be fitted up with shelves, to
serve as a pantry, in which case, four doors are
necessary, and the space between the first or outer
and the second door, and the space also between the
second and third doors, should be filled up with straw,
which may be conveniently packed up in large bags,
or cushions, and suspended from the ceiling. Barley-
straw is the best, on account of its being very flexible.
The space between the third and fourth doors forms
the pantry, the temperature of which may be reduced
by occasionally leaving the fourth or innermost door
open for a short time. In some cases, the body of
the ice-house is fitted with shelves as a pantry.
The form of ice-house usually adopted in this
country, frequently fails in ‘keeping the ice, from not
having double walls and double or treble doors, or
from imperfect drainage.
Fig. 1209 is the ‘ground-plan, and Fig. 1210 the
section of ' an ice-house of approved construction.
London says that it will keep ice throughout the
year in any climate, if covered with a suficient thick-
ness of earth or‘ straw. a is the well or cellar for the





Fig. 1209.
‘ice 5 6 a drain for carrying oif the thaw-water 5
c! a trap this drain, to prevent the external air
from, ‘communicating with that of the ice'house;
end d a, lead' pipe from this trap, connected with a
at.--e,.,for, pumping'upthe ice-cold water, for the
purpose ‘of ,cqqling wines, ‘or after filtration for
drinking.’ "There are five doors to this ice-house, at
g,'__lz,_ i, is ,-__ and _a‘ vacant‘ space l, cne foot‘ wide,
between the. twp naussmrelmding the cellar. and
covering. thecimicredivision of, the passage in. This

1‘? (el-)I'(En‘cyclopeedia; of.‘ Cottage; Farm, andrvilla Archiiectura

passage it may be used as a pantry, as already
noticed. The natural level of the ground is shown
at 92 ii; and the whole superstructure may be covered
in Britain to the depth of two or three feet with
earth, planted with ivy, and surrounded with trees.
tiff—ll Y IIL l
i ' " ’”
nil-""2;
, l l d
Fig. 1210.

‘e



In warmer climates the depth of earth ought to be
eight or ten feet. The size of the well ought also to
be increased, and a third vacant space round it might
be desirable. The space between the door i and i
should be filled up by a barley—straw cushion, and it is
desirable to have similar cushions against the doors g
and it, at least during summer. The two recesses 0
and 12 may be increased at pleasure.
In filling an ice-house, the ice should be broken
with mallets or stampers to a coarse powder, and
well rammed down in the well or pit, keeping the
upper surface concave, and adding a little water from
time to time, in order to fill up the interstices, and
assist the congelation of the whole into a solid mass.
It is even recommended to sprinkle the ice with salt
water (1 lb. of salt to every gallon of water) from a
common watering-pot, at intervals of two feet from
the bottom to the top of the mass, an extra quantity
being poured on when the filling is completed.
The freezing mixture, formed by 1 part salt, and
2 parts pounded ice, will sink a thermometer from the
ordinary temperature of a room to 5°; a degree of
cold somewhat approaching this being produced in
the ice-well, the ice is so firmly compacted together,
as to require a pickaxe to break it up the following
summer, and the salted ice, according to London,
will keep three times as long when exposed to the
air as fresh ice.
Snow is preserved in some places in a similar
manner to ice, by being rammed down in pits, and
well protected from‘the air at the surface. At
Naples, and in the 'soiith of Italy, even the poorest
persons-are accustomed, during the heats of summer,
to cool their with snow, which is collected
from the Apennine's, and‘ stored in pits dug chiefly on
the northern ‘side ef the‘ mountains. The snow is
thrown into these pits in .broad thick layers, and well
pressed-together until a considerable mass is col-
lectedijythe opening is" then filled up with branches‘ of
trees,'dried leaves, or, straw 5 and in some cases, a
ICE.
59
rude stone building is erected over it. A few of the
loftiest summits of the Apennines rise above the
snow-line, and are therefore covered with snow all
the year round; but from the lower ridges, the snow
melts away in summer, and it is only by making a
careful provision at the proper season, that a
supply is kept up during the summer. The lower
down the mountain the snow-cave is, the less trouble
in getting it at the season when it is most wanted,
but the greater the risk of its melting away. The
situation for the pit must therefore be carefully
selected, and the spot be well shaded by trees, or by
some projecting portion of rock, to keep off the rays
of the sun. On some rare occasions, a snow-shower
of considerable thickness will fall during winter on
thelower inhabited ridges. An occurrence of this kind
produces general rejoicing, for it saves the labour
of collecting snow from the heights. Men, women,
and children, rush out with shovels, baskets, &c., to
gather in their snow-harvest. Immense snow-balls
are made, and carefully rolled by the children to the
caves. The snow-harvest during winter gives em-
ployment to numbers of the peasantry 5 and the con-
veyance and sale of the same substance in summer is
also a source of constant activity. The task of con-
veying snow from the mountain caves and distributing
it in the various shops of Naples which sell that
article only, is performed during the night: mules
are loaded with the snow at the mouth of the caves,
and they convey it down the mountains to the boats,
which take it into Naples ; there it is deposited in a
large 0001 building, called “ La Dogana della neve ;”
or, the snow custom-house, where retail dealers come
from all parts of the town, to get their supply. The
snow-trade is in the hands of government, and pro
duces a considerable revenue. The dealers are bound
to sell the snow at a fixed price, and are fined if they
do not have a sufficient supply. The snow-shops, of
which there is one in nearly every street in Naples,
are kept open day and night during the season. Snow
is also collected in a somewhat similar manner in
Sicily, where the great store-house of snow is Mount
Etna.
Of late years, ice has become an article of com-
merce between countries where it is found in abun-
dance, and those where it is found scantily or not at
all. The place where this remarkable traffic com-
menced, is W'enham Lake, about 18 miles from Boston,
in the United States of America; and subsequently,
some of the Norwegian lakes have furnished abun-
dant supplies. The Wenham Lake Company was
formed, and we learn from the Blast-ruled London
News some particulars respecting their proceedings.
In September, 1833, a cargo of ice shipped at
Boston, was discharged at Calcutta, and sold at 3d.
per lb. while the native ice cost M. It was packed
in large cubes, fitting closely together so as to form
one solid mass, within chambers of double planking
with a layer of well-dried refuse tan or bark between
them. The quantity shipped, was 180 tons, of which
about 60 wasted on the voyage, and 20 on the
passage up the ‘river to Calcutta. Thousands of tons

are now annually shipped from Boston to our East
Indies, to the West Indian Archipelago, and to the
continent of South America. The company have
erected extensive ice-houses in London, and at Liver-
pool, and have arranged for importing into thisicoun~
try thousands of tons of ice every year. The masses
are so large, that they expose a very small surface to
the action of the air, and hence they suffer but-very
little loss. It is also stated, that ice frozen upon
deep water is more hard and solid than ice of ‘the
same thickness obtained from shallow water, and
melts more slowly. In Great Britain, the collection
and storing of ice is very precarious, on account of
the uncertainty of the supply during our mild
winters; but in America, where the cold of winter is
intense, the cutting, storing, and transportation of the
ice is regularly carried on throughout the winter.
Wenham lake occupies an elevated position, and
lies embosomed in rugged hills. The lake has no
outlet, but is fed by the springs which issue from the
rocks at its bottom, at a depth of 200 feet. The ice-
house, which is capable of storing 20,000 tons of ice,
is built of wood, with double walls 2 feet apart all
round, the intervening space being filled with saw-
dust. The machinery used for cutting the ice is
worked by men and horses. From the time when
the ice first forms, it is kept free from snow until it
is thick enough to be cut; the cutting being com-
menced when the ice is a foot thick. A surface of
some 2 acres is then selected, which, at that thickness,
will furnish about 2,000 tons, and a straight line is
then drawn through its centre from side to side each
way. A small hand-plough is pushed along one of
these lines, until the groove is about 3 inches deep
and 1}; inch wide, when the marker, Fig. 1211, is


introduced. This implement is drawn by 2 horses,
and'makes 2 new grooves parallel with the first, 21
inches apart, the gauge remaining in the original
groove. The marker is then shifted to the outside
groove, and makes 2 more. Having drawn these lines
over the whole surface in one direction the same
process is repeated in a transverse direction, marking
all the ice out into squares of 21 inches. Meanwhile
the plough drawn by a single horse follows in these
grooves, and cuts the ice to a depth of 6 inches. One
entire range of blocks is then sawn out, and the
remainder are split off toward the opening thus made
with an iron wedge, called an ice spade, Fig 1212 ;
when it is dropped into the groove the block splits
off with a very slight blow, especially in very cold
weather; the labour of splitting being slight or other-
wise according to the temperature of the air. Low
‘60
ICE.
platforms afe placed near the opening made in the
ice with iron slides extending into the water, and a
man stands on each side of a slide
armed with an ice hook, Fig. 1213,
with which. he ‘catches the ice, and
by a sudden jerk throws it up the
slide upon the platform. In a cold
day everything is quickly covered
with ice by the freezing of the water
on the platforms, slides, &c., and
the huge blocks of ice, some of
which weigh more than 2 cwt.
each, are hurled along these
slippery surfaces with great ease.
By the side of the platform is a
sled of the same height, capable of
containing about 3 tons, which
when filled, is drawn over the ice
to the front of the store—house, '
where a large stationary platform Fig-1213-
of the same height is ready to receive its load,
which, as soon as discharged, is hoisted a block at
a time into the house. . . .
Forty men, assisted by 12 horses, will cut and stow
away 400 tons a day. Sometimes in favourable weather
100 men are employed at once. When a thaw or a
fall of rain occurs, the ice is made porous and opaque
and unfitted for the market : when snow‘ is followed
by rain, and that by frost, the snow-ice thus formed is
removed by the plane. The operation of planing is
somewhat similar to that of cutting. A plane gauge
to run in the grooves made by the marker, and which
shaves the ice to the depth of 3 inches, is drawnby a
horse, until the whole‘ surface of the ice is planed.
The chips thus produced are then scraped off, and if
the clear ice is not reached the process is repeated.
If this makes the ice too thin for cutting, it is left
until a few nights of hard frost shall have added below
as much as was removed from’ above.
In addition to filling their ice-houses at the lake
and ' in the large towns, the Company fill a large
number of private ice-houses during the winter; all
the ice for these purposes being transported by
railway.
We come now to. the second part of our subject-—
the production of ice artificially; the most ancient
example of which is probably that carried on in the
upper country, near the town of Hoogly, about 40
miles from Calcutta. By a skilful application of the
process of evaporation the natives are able to procure
a supply-of ice during their short winter, viz. from the
end of November to the middle of February. The
ground where the ice is made is a large open plane:

Fig. 1212.
'3 or 4: troughs are formed, each about 120 feet in
length by 20 feet in width and 2 feet in depth: the
bottom is made smooth and allowed to dry by
‘exposure to the sun. It is covered with bundles of
rice straw to the depth of about a foot, and then loose
straw is strewed in, to within 6 inches of the adjoining
land. . The water to be. frozen is contained in pans
of unglazed porous earthenware, very much like those
put under' our garden flower-pots, and these are

‘arranged in regular order close to each other upon
the loose straw in rows to the number of 5 or 6,000.
The natives fill the pans with soft water by means of
small earthen pots, attached to the end of bamboo-
rods, long enough to reach half way across the
trough. The water is taken from large water-jars
sunk deep in the ground near the pits where the ice
is stored, and filled from the neighbouring pools or
with drainings from the ice. The quantity of water
poured into each pan varies from ,1,- to e of a pint,
depending upon the clearness of the sky and the
steadiness of the wind. The most favourable wind
is from the NN. w. : but any point between N. and w.
will ‘do, although less ice is produced. If the wind is
between E. and s. no ice will be formed. The ice which
begins to appear a little before midnight, is carefully
watched by persons stationed near each trough. As
soon as a slight. film of ice appears, the contents of
several pans are mixed together, and the freezing
liquid sprinkled over the others. The freezing con-
tinues till sunrise, when perhaps as much as half an
inch of ‘ice will be found. in each pan. In very
favourable nights the water is entirely frozen. The
ice is generally removed by women, '7 or 8 of whom
are appointed to each ice-bed: they use a blunt semi-
circular knife to scoop out the ice, which they throw
together with any unfrozen water into earthen vessels
placed near them. When these are full their contents
are poured into conical baskets, placed over the large
water-jars from which the pans are filled; by which
means a supply of cool water is collected for the next
night’s operations. When the ice has been sufficiently
drained, it is deposited in wells near the ice-beds;
and at nightremoved to large circular pits lined with
mats, and covered over with a straw shed. The heat
of the day, even in the ice-making season, is frequently
greater than that of the hottest summer days of
England, so that after all precautions, a partial
thawing goes on in the pits. The water thus pro-
duced is carried off through holes in the bottom of
the pits to a deep well, which also serves to supply
the pans in the ice-bed: thus throughout the process
the cold is economised as much as possible. The ice
is conveyed in boats to Calcutta by night. l/Vhen
the weather is coldest it is simply packed in bags; at
other times in baskets lined with straw mats, and
conveyed to the city, before sunrise. During the
hot season, when ice is most needed, it is scarcely
possible to preserve it in any quantity, and the first
heavy fall of rain usually melts all that is left of the
last ice-making season., ' I
The principle of evaporation has been commonly
applied in all ages to the cooling of liquids. A
porous vessel which allows a minute portion of the
liquid contained in it to ooze out so as to keep the
surface constantly moist, gets rid of this surface
moisture by converting it into vapour, which is being
constantly discharged from it, and as the heat required
for the formation of this vapour is derived from the
vessel itself and its contained liquid, the temperature
of the latter speedily falls. Abottle of water covered
tightly with a cloth“ kept wet and exposed to the
ICE.
61
sun or to the wind, will in a short time fall many
degrees below the temperature of the air.
Sir John Leslie carried the principle of evaporation
so far as to be able to freeze water in a few minutes
by placing it under such circumstances, as to cause
it to form vapour rapidly, and then removing the
vapour as fast as it was formed. We will‘ first speak
of his method of cooling liquids. It‘ is known
that unless means be taken for the absorption of the
water evaporated from the porous vessels, the air
will become so saturated as not to admit of further
evaporation, especially in a confined mass of air 5 and
he therefore proposed to place near, and exterior to
the vessel containing the liquid, some substance
which absorbs moisture with avidity. Dry flannel
was found to absorb very well ; as also trap rock and
compound clays reduced to a coarse powder and dried
before a strong fire ; parched oatmeal acts with
energy as an absorbent, as also does muriate of lime.
But it was found that strong sulphuric acid was the
most powerful absorbent, continuing for a long time
with slowly diminishing force to attract moisture and
capable of having its absorbent powers restored by
the application of heat. There are, however, so many
and such powerful objections to the habitual domestic
use of so highly poisonous and corrosive a substance
as sulphuric acid, that we can neither recommend it
nor hope to see ‘it adopted; but as this plan may be
of use in certain manufacturing processes we gave an
outline of Sir John Leslie’s method. He says :——-“ To
cool water in any climate or state of the atmosphere,
we have only therefore to put it into a small porous
vessel, presenting on all sides a humid surface, and to
suspend this within a close wide cistern, of which the
bottom is covered with a layer of sulphuric acid.
The broad surface of the acid absorbing the moisture
as fast as it diffuses itself through the confined air,
keeps that medium constantly at a point of extreme
dryness, and thus enables it to support with undi-
minished vigour the process of evaporation.” He
recommends the use of a cis-
tczrn or refrigerator, Fig. 1214:,
"'""““‘ ~~_ o. a broad cylmdrical form,
from 12 to 16 inches in dia-
J meter, composed of dense
glazed earthenware. This is
Ali to be placed in a cellar or
other cool place, and charged
with sulphuric acid to the
depth of about @1- inch. A porous earthen pot being
filled up to the lip with water, is set upon a low
porcelain stand in the middle of the cistern, to which
the lid or cover is then carefully fitted. The cooling
is completed in from 3 to 5 hours, when the water
should be removed. The production of cold is greater
when the refrigerator is large, or when a small pot is
used, insomuch that the effect will be diminished one
half, if the humid surface should equal that of the
acid. The power of the refrigerator is always the
greatest at the season when it is most wanted; that
is, a given quantity of water on a hot day can be
lowered a greater number of degrees than on a cold day.


Fig. 1214.

When the thermometer is at 95° in the open air, the
refrigerator will reduce the water in the porous vessel
to 59°, but when the thermometer is at 50° the
water can be cooled to 32°. By supplying a suc-
cession of porous earthen pots, the acid will continue
to act till it has absorbed half its weight of moisture,
during which time it will have assisted in cooling
about 50 times that quantity of water exposed to
evaporation. Butter may also be kept cool for the
table in summer, by putting it after being washed
with water into a wet porous pot, and shutting this
up for a couple of hours in the refrigeratory. To
cool wine sufficiently, one bottle only is used at a
time in the smallest refrigeratory. A sheath of
stocking or flannel, previously soaked in water, being
drawn over the body of the bottle, it is laid in a
reclined position on a porcelain slider near the sur-
face of the acid, and left shut up for 3 or 4 hours.
But by the use of the air-pump Leslie showed, in
a striking manner, the absorption and disappearance
of sensible heat during evaporation. A shallow dish
of sulphuric acid was placed on the table of the air-
pump, and over this, upon a glass tripod, a metal
vessel containing water. On covering this with a
receiver, and pumping out the air, the water first dis—
charges the air dissolved in it, and by the rapidity of
its evaporation appears to boil. As fast as the vapour
is formed it is absorbed by the sulphuric acid, and as
the heat necessary to the formation of this vapour is
derived from the water itself, the latter quickly loses
the heat necessary to its existence in the fluid form,
and it becomes solid or freezes. If during thispro-
cess the bulb of a thermometer be kept in the water,
it will be observed that the temperature falls several
degrees below the freezing point before congelation
takes place; but as soon as it freezes it rises to 32°
in consequence of the escape of the residuary latent
heat. Leslie proposed this method as a means of pro-
curing ice in hot climates, and suggested for the pur-
pose a large single-barrel air-pump, capable of exhaust-
ing 6 or 8 receivers at a time. Attempts have also
been made to form ice on this plan on a large scale,
by the evaporation of ether contained in a separate
vessel under the same receiver with the water, and
to pump out the vapour of ether, thus formed, into
a separate condenser, so as to be able, for the sake
of economy, to use the same ether over and over '
again. All these plans have failed in practice on
account of the comparatively great expense and the
small produce of ice. '
The production of cold by freezing mixtures de-
pends upon the general law, that in the conversion of
a solid into a liquid a quantity of heat, not indicated
by, or sensible to the thermometer, is absorbed or
disappears, which heat is withdrawn from the sur-
rounding bodies. If the solids he suddenly or rapidly
liquefied, the absorption of heat, i. e. the production
of cold, is very marked. Thus when common salt in
fine powder is mixed with snow or pounded ice, these
solids suddenly liquefy and run down into brine,
which does not freeze till reduced to nearly 0°. A.
mixture of ice and salt is used by confectioners in the
62
ICELAND MOSS—IMPACT—IMPENETRABILITY.
preparation of ices.1 A mixture of about 3 parts of
freshly-gathered, light, flocculent snow, with 2 parts
of chloride of calcium, made in earthen vessels pre-
viously cooled, will depress the thermometer from
32° to between 40° and 50° below zero, a tempera-
ture at which mercury freezes. By the successive
application of freezing mixtures in a proper apparatus,
Vt’alker succeeded in sinking the spirit thermometer
to —91°. Some of the most useful freezing mixtures
are given in the following table :—
MIXT‘U nus. PARTS. THERMOM. SINKS.
Sal Ammoniac............... 5
Nltre 5 } from 50° to 10°
WaterltlICI'II‘GIIIDIIIOIQICOIAI vI‘lilriz‘iit'zlt.e of Ammonia ..... .. Tl } " 500 H 40
Sulphate of Soda............ 5 1{ 50° , 3..
Dilute Sulphuric Acld..... 4 1 ” ’
SHOW looooaaoaoolCollege-Insist. 1 } ,, 32° ,, 0Q
Common Salt ............... .. l
éi'iigiivate of Lime 2 } ” 320 H _5O°
Snow 2
Dilute Sulphuric Acid..... 1 } ,, —lO° ,, —56°
Dilute Nitric Acid ....... .. 1
Snow, 01' Pounded Ice 12
Common Salt 5 } ,, 16° ,, —-2.3°
Nitrate of Ammonia .... .. 5
ll...-IIIIIIIIIIOOIIIIIIO.‘ 1 Muriate of Lime 3 " ”
SDliu‘irze Sulphuric Ac1d..... lg n __680 n _910
Ice and salt furnish the cheapest and most conve-
nient freezing mixture; but where ice cannot be
procured the salts mentioned in the first two reci-
pes given above may be used, and the salts recovered
by evaporation when they have served their pur-
pose, so that they can be used over again. “ In
employing them to cool a bottle of wine, a vessel
should be selected a little larger and nearly as tall as
the bottle: this vessel should then be filled with the
coldest water that can be procured, and the bottle
placed in it : about 41 ouncesof the salt in fine pow-
der should be sprinkled upon the shoulder of the
bottle, so as, gradually dissolving, to fall or run down
its sides; as the salt dissolves, the bottle should be
gently turned in the mixture, and kept in it till an
immersed thermometer tells us that the temperature
is rising, which will be in 20 minutes or half an hour.”
(Bramla) A convenient process for freezing a little
water, without the use of ice, is to drench finely-
powdered crystals of sulphate of soda with the un-
diluted hydrochloric acid of the shops. The .salt
dissolves to a greater extent in this acid than in
water, and the temperature may sink from 50 ° to 0°.
The vessel in which the mixture is made becomes
covered with boar-frost, and water in a tube im-
mersed in the mixture is speedily frozen. (Gm/mm.)

(l) The cream, or other liquid to be frozen, is contained in
a. thin metallic pan in the cold brine produced by the melting of
the ice. Mr. Masters, the confectioner, in his I ce-Book, published
in .1844, states, that unless the ingredients of the ice be kept in
cdnstant agitation during its formation, the watery portions freeze
out and separate from‘the richer saccharine matters, and a badly
formed ice is’the consequence. To prevent this he has invented
akjnd of churn, which ,keeps thezingredients in a constant state of
agitation during the congelation.

ICELAND MOSS. Lia/zen islaadz'cus. A lichen,
growing freely on the mountains of Scotland, and
occasionally employed in invalid diet, to form a jelly
which possesses certain tonic and nutritive properties.
In the sterile island whose name it hears it is how-
ever an important article of food, as a substitute for
wheat-flour. It is washed, dried in the sun, and
reduced to powder, by stamping in strong bags, after
which it only requires sifting to make it applicable to
the ordinary purposes of meal or flour. The plant
consists of upright leaves, of the peculiar membranous
texture common to lichens: these are soft and pliant
when moist, but rigid and brittle when dry. The
organs of fructiflcation are sprinkled over the exterior
surface like small black warts, and the edges of the
leaves are fringed with short hairs. The whole plant
is smooth and shiny, and inclines to a reddish hue
towards the roots.
ICELAND SPAR. Transparent crystalline calc
spar, first brought from Iceland. It shows double
refraction well.
IGNITION, (from z'gm's, fire,) a property which
bodies possess of giving out light whenever their
temperatures are raised up to a certain point. The
term z'rzcanclescence, (from incmzdesco, to grow very hot.)
is generally applied to bodies at a high temperature,
which emit light without flame.
ILLUMINATION, ARTIFICIAL. See CANDLE
——LAMP-—GAS-LIGHTING.
IMPACT, (from in and pamyo, to strike) the meet—
ing of bodies which are in motion, whereby such
motion is modified or destroyed. The subject is one
of great interest in scientific mechanics. The princi-
pal laws of impact are, 1. The common velocity of
two non—elastic bodies after impact, when they both
move the same way is found by dividing the sum of the
products of each body into its respective velocity, by
the sum of the bodies; 2. When the bodies meet
each other, divide the difference of the products of
each mass into its velocity, by the sum of the bodies,
for the common velocity after impact. The import-
ant law that the angle of incidence is equal to the
angle of reflection can also be proved by impact.
IMPENETRABILITY. The two necessary and
essential properties of all matter are 62256222.‘ or volume,
and z'ztpeaetmdz'lz't‘y. It is impossible to form any
conception of matter without allowing it some extent,
for the smallest conceivable speck must have length,
breadth, and thickness; and must therefore occupy
a space into which a second speck cannot possibly
enter until the first has moved away: this is all that
is meant by the impenetrability of matter.
There are however certain cases of apparent pene-
tration of matter: thus, salt may be dissolved in
water without increasing the bulk of the fluid, a fact
which can only be accounted for on the assumption
that the matter of the fluid has interstices or pores,
and that the particles of the solid accommodate them-
selves therein as sand would do if mixed with bullets.
IMPULSE. Any cause by virtue of which velocity
is suddenly communicated to a body.
INCANDESCEN CE. See IGNITION.
INDIGO.
as
INCIDENCE, Angle of. See HEAT, Fig. 1136.
INCLINED PLANE. See MECHANICS.
INDIAN INK. See INK.
INDIAN RUBBER. See Caourcnouc.
INDIGO. This valuable dye is obtained from
tropical plants growing wild, and also cultivated for
dyeing purposes, in Asia and America. In the 13th
century, Marco Polo found the manufacture of indigo
extensive in India, and gave descriptions of the
plants which yield the dye, and their mode of treat-
ment, but his accounts were little known or believed,
so that long after the dye had been obtained direct
from India, under the name of iniiennz, the most
erroneous notions prevailed as to its real nature. At
I-Ialberstadt, in Germany, it was sought for as a
mineral, and was included by name in the letters
patent granted to some proprietors of mines for the
erection of their works.
The product is obtained from numerous species of the
genera I ncligofizm, Isnzfis, and Nerinm, but principally the
first named. Thus the Indigo/em .iz'nei‘orin of Bengal,
Malabar, &c. yields large quantities of the dye, though
not of the best quality: a finer kind is the product of
I. elispernia, growing in the East, and also in America,
where it yields the Guatemala—indigo: I. nnil, and
I. nrgenien, are other species yielding good indigo,
the latter being found also in Africa: I. ‘e/Znnen is the
species common to Egypt and Arabia: while I. pseudo-
zfz'nez‘orin, which is the best of all, is cultivated in the
East Indies. Indigo/‘em iineio'rin, as propagated in
the West Indies, is described as having a root about
a quarter of an inch thick, and more than a foot long,
having a faint smell resembling parsley. From this
root issues a short bushy stem of about the same
thickness, hard and woody, not rising more than 2
feet. The leaves are winged, or consist of several
pairs of leaflets, ranged on each side a long foot—stalk,
and having a terminal leaf at the extremity. For
about one-third of its upper extent, also, the stem is
laden with spikes of very small flowers, destitute of
smell, succeeded by long crooked brown pods, in-
closing small yellow seeds. Indigo is called “ the
child of the sun,” as it cannot be successfully culti-
vated anywhere except within the tropics. The In-
digoferae, in common with other leguminous plants,
must be considered as having deleterious qualities,
but in this, as in many other examples, they are not
sufficiently developed to prove injurious. Some of
the indigo plants are used as fodder, just as clover,
saintfoin, and other members of the same great
natural family are with us. Partly on account of the
supposed injurious qualities of indigo, but principally,
no doubt, through a jealous apprehension that this
dye would supersede the British woad, it was de-
nounced in the time of Elizabeth as a dangerous
drug, and an act was passed, which remained in force
until the time of Charles II., authorizing searchers to
burn both it and logwood in all the dye-houses where
they were discovered. The prejudice against indigo,
both in England and France, is said to have been
maintained by the belief that it was a fugitive colour,
and injurious to the quality of the wool. After a

time, how ever, when indigo began to reach this coun-
try from America as well as Asia, and when the
French also brought indigo from the African coast,
it gradually took its place among the best dyes, and
has now long been recognised as one of extreme
value, for which no worthy substitute can be found.
In the eastern mode of cultivating indigo, the
seed ‘is sown in March, and April, in a light but rich
soil, at the rate of twelve pounds of seed to the acre,
and the growth of the young plants is so rapid that
in June or July they have arrived at maturity, denoted
by the expansion of the blossoms, at which time the
dyeing principle is most abundant. The first cropping
of the plants then takes place, but a second, third,
and even a fourth may follow in the same season.
The colouring matter is obtained from the whole plant,
either by fermentation of the fresh leaves and stems,
or by maceration of the dried plant. In the former
case the fresh plants, as they are cut off and brought
in from the field, are placed in a large stone cistern,
which is filled with them to within a few inches of
the brim. In order that they may not swell and rise
out of the vat during fermentation, beams of wood
are laid on them and braced down with twigs of
bamboo. Active fermentation soon commences, and
is revealed by the frothy bubbles rising to the surface,
at first White, then grey-blue, and at last deep purple,
when a copper coloured scum also spreads around.
The fermentation is now at its height, and the liquor
agitated: when it begins to subside the liquor is
drawn off into a lower cistern, where it exhibits a
glistening yellow colour, changing to green. Several
men are then employed in beating the liquor with
oars or shovels, while others take off the bamboos
and clear out the upper vat of the waste material,
(which is dried for fuel,) and prepare it for a fresh
charge. The beating of the, liquor is continued for
an hour and a half; and by its means a great quantity
of carbonic acid is disengaged, and the particles of
indigo get thoroughly exposed to the atmosphere,
and obtain their requisite supply of oxygen; afterwhich
they agglomerate in flocks or granulations, the whole
assumes the colour of Madeira wine, and on the
cessation of the beating, the indigo gradually subsides,
leaving the liquor transparent. When the grain is
precipitated, the clear liquor is drawn off and allowed
to run to waste in some spot where it will not mingle
with a brook or pond frequented by cattle, (on
account of its deleterious qualities.) A labourer then
enters the vat, sweeps up the thick and pulpy matter,
and discharges it into a cistern alongside of a large
boiler, into which it is passed through a strainer, and
heated to ebullition. By this process it is enriched
in colour, and increased in weight. From the boiler
the mixture is run into a receiver called the dripping
cat, which has a false bottom of woollen web, through
which the liquor filters. As long as it passes through
turbid, it is pumped back again into the receiver, but
when it runs clear, it is allowed to drain through
slowly. The day following, all the drained indigo is
put into a strong bag and squeezed in -a press. It is
then taken out, cut into cubes with a brass wire, and
641
Immeo.
placed upon wicker-work shelves to dry. A whitish
etilorescence soon covers the pieces. This is brushed
off; but in some places the cakes are fermented by
placing them in heaps in a cask until moisture exudes,
after which they are finally covered with a white
meal. Five or six days’ drying completes the process,
and fits them to be packed for exportation. . a
When the dried plant is'u'sed instead‘ of the fresh,
(and this is said to be the better method,) the indigo
croppings are spread in the sun, like hay, and when
dried, are storedinmagazines till 'a suflicient quantity
be collected for the purposes-of the‘ manufacture.
The dried plants are infused in the steeping vat with
six times their bulk' of water, and: are allowed to
macera'te for two-hours with continual stirring till‘ all
the ‘floating leaves sink. The fine green‘ liquor is
then drawn ofi into the second vat, and’ beaten as
before. Hot water is, sometimes used for macerating
the plant, but this ‘does not appear'to-be: necessary.
In the year ending January 1851,v '7 OASQ cwt. of
indigo were imported: it pays no duty. The indigo,
as imported in cubic cakes, is friable, more or less
brittle, and of various shades of peculiar deep blue.
When rubbed with a hard body it exhibits a copper-
red appearance. The best indigo is so light that
it will swim upon water. Its ~quality depends upon
the species of plant,'the soil and climate in which it
was grown, and the' details of the manufacture. ' The
proportion of pure indigo (indigo clue) contained in
different samples, has not been found to average more
than 50 per cent. Crude indigo may be roughly
analysed by subjecting it to the successive action of
boiling water, alcohol and weak solutions of hydro-
chloric acid. 100 parts of - Guatemala indigo thus
treated by Chevreul afforded as follows :—
' (Green matter combined with ammonia
Deoxidized indigo . 12
To Water """ Extract Green matter ................................ .-
To Alcohol ..... 30
, A trace of indigo................ .. Red resin 6
To Hydrochloric{Carbonate of lime 2
Acid Oxide of iron
Alumina .... ..
. 3
Resldue """"" "{Pure indigo 45
100
Pure indigo (Cm H5 02 N), also known by the ‘names
indigo-Mae, and z'rzclzf‘gotz'ne, may be obtained from the
indigo of commerce in various ways, both by precipi-
tation and by sublimation. By the latter process
Mr. Taylor mixes 1 part indigo with 2 parts plaster
of Paris, converts the whole into a paste with water,
and spreads it to the thickness of about 35‘ inch upon
an iron plate. This, when quite’ dry, is heated by a
large spirit lamp. The volatilization of the indigo is
assisted by the vapour of water disengaged from the
gypsum,’ and the surface of the mass becomes covered
with beautiful‘ velvety crystals of pure indigo, which
may be easily removed by a thin spatula. If the
temperature be too high, the indigo is charred and
decomposed. 4 Its subliming point is about 550° : its

melting point, its point of volatilization, and that at
which it is decomposed, are ‘very near each other.
When projected on a hot body it gives off a purple
vapour as intense as that of iodine, fuses, boils, and
burns with a brightfiame, giving off much smoke.
Sublimed indigo-blue is in the form of flat needles
and four-sided prisms, which, seen at a particular
angle, have a peculiar and intense copper colour:
when lying in heaps they are of a rich brown. The
crystals also occur in broad thin plates, which are of
a splendid blue colour by transmitted light.
Indigo-blue is without taste or smell: it is neither
basic nor acid: it is perfectly insoluble in water and
in ether: boiling alcohol merely dissolves a trace of
it. Hot olive oil and oil of turpentine‘ acquire a
blue tint from it, but on cooling they deposit the
minute portion taken up. It is not affected by dilute
acids or alkaline solutions. Vegetable blues usually
indicate the presence of acids, by becoming of a red
colour: indigo is an exception to this rule, and it is a
remarkable fact, that sulphuric acid dissolves it with-
out affecting its colour: 15 parts of concentrated
sulphuric'acid digested with indigo for 3 days form a
deep blue pasty mass, which is entirely soluble in
water, and. is often used in dyeing. It has been
named- salplzz'adylz'c ‘acid, and forms blue salts with
alkaline bases. If the quantity of acid used for the
solution be insufficient, or sufiicient time be not allowed
for digestion, on diluting the acid mass, a purple
powder is left soluble in a large quantity of pure
water. The Nordhausen sulphuric acid answers
better for dissolving indigo than ordinary oil of
vitriol.
One of the most curious and valuable properties of
indigo, is the comparative facility with which it loses
its colour, becomes soluble so as to allow it to be
used as a dye, and then by exposure to the air it
reassumes its blue tint and becomes again insoluble.
[See Drama] This change takes placewhen‘indigo
is brought into contact with certain deoxidizing
agents‘ and an alkali, and it is probable that under
these circumstances the indigo returns to the state in
which it existed in the plant. In preparing his
indigo-cat the dyer uses 5 parts of powdered indigo,
10 parts‘ of sulphate of iron, 15 parts of hydrate of
lime, and 60 parts of .water: these are .agitated
together in a close vessel and then left to stand.
The salt of iron in conjunction with an excess of lime
reduces the indigo to the soluble state; a'yellowish
liquid is produced, from which, if oxygen be carefully
excluded, the white or ldeoa'z'zlizéd indigo is precipi-
tated ‘in a fiocculent form by an acid, such as the
acetic or hydrochloric." Cloth steeped in the alkaline
liquid, and then‘ exposed to the air, acquires a deep
and permanent blue tint, by the absorption of oxygen
and the deposition of solid insoluble indigo in the
substance of the ‘fibre. A mixture of dilute caustic
soda and grape sugar may-be used instead of the iron,
salt, and lime, in the above process; the sugar
becomes oxidized to formic acid, and the indigo
is reduced.
The white indigo appears to be formed by the
INK. - 65 '
accession of hydrogen. Thus blue insoluble indigo,
consists of 016 H5 N02, and white or reduced indigo
of C16 H6 N02. White indigo may also be regarded
as a hydrate, and blue indigo as an oxide of one and
the same substance; white indigo being represented
by the formula C16 H5 NO + HO, and blue indigo by
CI, H5 NO + O.
Indigo is especially interesting to the chemist, and it
has been studied with great assiduity by some of the
most distinguished chemists. The subject is treated
with tolerable fulness in the 8th vol. of Dumas’s
Traité de Chimie appliquée aux Arts, and also in
Brande’s Manual of Chemistry.
INFUSION—See Drcoo'rron.
INK is variously composed according to the pur-
poses to which it is to be applied. Oommori wrilirig
iii/e is the pertannate of iron, mixed with a little
gallate, held in suspension in water by means of gum
or some other viscid substance. The gum also pre-
vents the ink from being too fluid, and also serves to
protect the vegetable matter from decomposition. A
very good ink may be formed from the following
recipe: Take Aleppo galls finely bruised, 6 oz. ; crys-
tallized sulphate of iron, lion: gum arabic, lloz. ;
water, 6 pints. Boil the galls in the water, for about
2 hours, occasionally adding water to supply the loss
from evaporation; then add the other ingredients, and
keep the whole for two months in a wooden or glass
vessel, which is to be occasionally shaken. Then
strain the ink into glass bottles, adding a few drops
of kreosote to prevent mouldiness.
When the ink has not been kept long enough, and
is pale in writing, it becomes black in consequence of
the oxygen of the air converting the protogallate and‘
prototannate of iron into pergallate and pertannate ;
but when writing becomes yellow and indistinct from
age, it is from the decay of the vegetable portion of
the ink, little more than peroxide of iron being left
on the paper. By the careful application of infusion
of galls the writing may be rendered blacker and more
legible, or by washing the writing with a weak solu-
tion of oxalic or hydrochloric acid, and then applying
an infusion of galls. When the writing paper has
been made from inferior rags, bleached with excess of
chlorine, the best inkhecomes discoloured. Logwood,
sulphate of copper, and other ingredients are occa-
sionally added to ink, but their effect is injurious.
Blue iii/s has of late years been much in request :
the colouring matter is said to be sulphate of indigo
and tannogallate of iron; or, according to another
recipe, Prussian blue dissolved in water by means of
oxalic acid.
Red is usually made by boiling about 2 ounces
of Brazil wood in a pint of water for a quarter of an
hour, and adding a little gum and alum. A superior
description of red ink may be formed from an ammo’
niacal solution of carmine. [See CAniunvn]
The great merit of our common writing ink is the
freedom with which it flows from the pen, allowing of
rapid writing; and the manner in which it bites into
the paper, so as not to be removed by sponging. The
great defect is want of durability. Such inks partake
voL. II.

rather of the nature of dyes. The writing ink of the
ancients, on the contrary, is characterised by great
permanency; its basis was finely divided charcoal
mixed with some mucilaginous or adhesive fluid.‘
Iridiaa or China iii/e is of this character: it is formed
of lamp-black and size or animal glue, with the ad-
dition of perfumes, not necessary, however, to its use
as an ink, and is made up in cakes. It is used in
China with a brush both for writing and for painting
upon Chinese paper; and it is used in other countries
for making drawings in‘ black and white; the dif—
f erent depths of shade being produced by varying the
dilution with water. The lamp-black must be ex-
ceedingly fine, and the ink be prepared with great
care.
The permanent character of carbonaceous inks
would recommend them to more general use, if a.
sufliciently fluid vehicle could be found for them.
According to Professor Traill, an acetic solution of
gluten, forms an excellent basis of a durable and
indelible writing ink. The gluten is obtained as
usual by kneading the dough of wheat flour in a
stream of water until the starch is completely sepa-
rated: the gluten should be kept from 241 to 36 hours
in water, and then be digested in acetic acid of specific
gravity 1033 to 1034.‘ in the proportion of ‘3 parts
gluten to 20 of the acid. By means of a gentle heat
a greyish white saponaceous fluid is obtained, which
will keep for a long time. The colouring matter is
from 8 to 12 grains of the best lamp-black, and 2
grains of indigo thoroughly incorporated with each
fluid ounce of the vehicle. An agreeable aroma may
be imparted to the ink by digesting bruised cloves,
pimento or cinnamon in a portion of the original acid.
This ink is not adapted for writing on parchment,
but may be used on paper with a steel pen, which,
however, should be washed after use.
Prirzler’s irz/e is of two kinds, one for letter-
press and the other for copper-plate printing. The
former is prepared by boiling linseed or nut-oil in an
iron pot: it is kindled and allowed to burn for half-
an-hour: the vessel is then closely covered over to
extinguish the flame: it is again boiled in order to
give it the proper drying character, and it is then
mixed with lamp-black for black ink; or Vermilion
for the finer works in red ink; or the pigment is
varied according to the colour. For copper-plate-
printer’s ink the oil is less boiled, and the carbon
used is Frankfort black.
Marking irzls, used for marking linen, is a solution
of nitrate of silver written with a pen upon the linen
previously moistened with an alkaline solution, such
as potash or soda. In this operation oxide of silver
is precipitated upon and combines with the cloth in
a. very firm manner. The bottles of indelible marking-
ink are prepared by dissolving 2 drachms of pure
nitrate of silver and 1 drachm of gum-arabic in '7
drachms of distilled water coloured by a little China
ink. The preparatory liquid is made by dissolving
2 ounces of crystallized carbonate of soda and 2
drachms of gum-arabic in i ounces of water. A much
more convenient marking-ink is that used by the
F
66
IODINE.
bleachers, viz. coal-tar, made sufficiently thin with
naphtha to write with.
Sympathetic Z'YZdIS are noticed under COBALT. The
inks for what are called C’lzemz'eel' Landscapes, have
lately been increased in number. Acetate of cobalt
affords an azure blue; chloride of copper a gamboge
yellow; chloride of cobalt an Olympian green, and
bromide of copper a fine brown.
INTAGLIO—See SEAL-ENGRAVING.
INTRADOS and EXTRADOS, the inferior and
exterior curves of an arch. See Barnes, vol. i.
p. 198.
INULINE. See Srxnon.
IODINE, an elementary substance (i. 126), was
discovered in 1811 by M. Courtois of Paris, a manu-
facturer of salt-petre, in the mother-liquors of that
salt. Its affinity for other substances is so strong
that it does not occur in nature in a separate state.
It is found combined with potassium and sodium in
many mineral waters, and also in a minute propor-
tion in sea-water, from which many marine plants
and animals have the power of separating it and
accumulating it in their tissues. It is also found in
a few minerals.1L Much of the iodine of commerce is
prepared at Glasgow from the kelp of the western
coast of Ireland and the western islands of Scotland;
and the process for obtaining it has been described
by Professor Graham? The sea-weed thrown upon
the beach is collected, dried and burned in a shallow‘
pit, in which the ashes accumulate and melt by the
heat. The fused mass, broken into lumps, is kelp,
which was formerly prepared for the sake of its car-
bonate of soda, varying from 2 to 5 per cent. The
long elastic stems of the fucus palmatus are said to
afford most of the iodine contained in kelp. The
kelp is broken up small, treated with water, the solu-
tion filtered and evaporated to a small bulk, the
chloride of sodium, carbonate of soda, chloride of
potassium, and other salts being removed as they
successively crystallize. A ‘dark brown mother- liquor
is left, which contains nearly all the iodine: this is mixed with sulphuric acid and peroxide of manganese, and heated gently in a leaden ‘I
retort a, Fig. 1215, of a cylindrical form, 1 ft


Fig. 1215.
supported in a sand‘ bath, and heated by a small fire
below. The retort has a large opening, to which a
capital, 6 e, is luted, containing'two openings of un-
equal size, 6 0,‘ closed by leaden stopples. A series
IODINE STILL.

(1‘) A copious list of the sources of iodine is given in Gmelin’s
Hand-book of Chemistry, vol. ii. '
(2) Elements of Chemistry, 1842.

of bottles (Z, having each two openings, are luted
together ‘as shown in the figure, and are used as
condensers‘; the prepared ley being7 heated to about
140° in the retort, the manganese is introduced.
Iodine immediately begins to come off, and collects
in the condensers. The-progress of its evolution is
watched by occasionally removing the stopple ate,
and additions of sulphuric acid or manganese are
made at b if necessary. The success of the opera-
tion depends upon its being slowly conducted, and
upon the proper management of the temperature.
The theory of the operation is similar to that of the
process for preparing chlorine [See CHLonnvn]. The
manganese, however, is not {indispensable in this pro-
cess, for iodide of potassium or sodium, heated with
excess of sulphuric acid, evolves iodine.
Professor Graham has recently examined the ashes
of sea—weeds used as fuel in the island of Guernsey.
“ Having observed that large quantities of deep sea
fuci were collected by the inhabitants, spread out to
dry in the fields, then used as common fuel in their
houses, and the ashes carefully ‘saved as a valuable
manure for their land, it occurred to him that these
ashes might contain a larger quantity of iodine than
the ordinary kelp, both on account of the source from
whence the fuci were derived, and the comparatively
low temperature at which the combustion was effected 5
for there could be little doubt that inthe manufacture
of Scotch kelp a portion of the iodide of sodium present
was lost by sublimation.” On examining these ashes
they were found to be very rich in iodine.
Professor Bechi of Florence has lately invented
a method for extracting iodine from mineral waters.
This method is founded on the property which char-
coal has of retaining iodine, and afterwards readily
yielding it to other substances. The iodides contained
in the mineral water are first decomposed by means
of chlorine or acids, and the water is then passed
through a filter containing a large quantity of calcined
lamp-black: after passing through several layers of
this charcoal, the water is completely deprived of its
iodine. Having washed the charcoal, it is mixed with
hydrated oxide of iron, placed on a filter, and water
poured over it several times to remove all the iodide
of iron. The solution of iodide of iron being treated
with sulphate of copper, iodide of copper is formed,
which, being heated in a retort with oxide of manga-
nese and sulphuric acid, the iodine is distilled over.
The charcoal used in this operation is washed with
dilute hydrochloric -acid, to separate any remaining
oxide of iron, and thus purified, it is used for another
operation.3 ‘ '
Iodine crystallizes in ‘plates or scales of a bluish-
black colour, and imperfect metallic lustre. Its den-
sity is. 41'9118. It fuses at 225°, and boils at 34.70,
emitting a vapour of a beautiful violet colour, whence

(3) Signore Bechi’s Essay gained the prize ofi’ered by the Aca-
demy of the Fine Arts of Florence, in 1849, for his answer to the
question-—“ To find an economical and easy means of extracting
iodine, not only from all its natural combinations existing in the
soil of Tuscany, but also from every other artificial combination.”
The Essay is given in the “ Journal de Pharmacie,” July 1851,
and also in the “ Chemist,” for September 1851.
r
' lPECACUANHA—eIRIDIUM—JRON.
67
the name of this substance from 136817;’, violet-coloured.
It is slowly volatile at common temperatures, ex-
haling a peculiar odour something like that of chlo—
rine. The density of the vapour is 8716. It dissolves
in about 7,000 parts of water, to which it gives a
brown colour; but in alcohol it dissolves freely. It
stains the skin of a deep brown, which is not perma-
nent. It acts with energy on the animal system, and
is much used in medicine.
The chief use of iodine in the arts arises from its
characteristic property of producing a splendid blue
colour by contact with starch. A liquid, containing
one 4150,000th of its weight of iodine, receives a
blue tinge when a solution of starch is added to it.
In order to act as a test, the iodine must be free or
uncombined, for which purpose, when the presence
of a soluble iodide is suspected, a small quantity of
chlorine water, added to the solution, will liberate
the iodine so as to allow it to act on the starch.
Iodine and bromine are also used to form the film of
iodide or bromide of silver in the silver plates of the
daguerreotype.
Iodine unites with hydrogen, forming hydriodic
acid (HL), and with oxygen forming iodic acid,
105, and hyperiodic acid, 107. .
IPEGAGUANHA, the root of several plants
growing in South America. They all contain similar
ingredients, but differ in the amount of the active or
emetic principle, called emetina, contained in them.
The best ipecacuanba is the annulated: it is produced
by the Cep/zaé'lz's Ipecacaaa/za, a small shrubby plant,
of which there are 3 varieties, the M02072, the red, and
the grey, or grey-while, also called greater amzalaz‘erl
z'pecacaaa. This is the only sort sent from Rio
Janeiro, and is sometimes called Brazilian or Lisbon
z'pecacaaa. It is sent in bales and barrels. “ The
root is in pieces from .‘2 to 6 inches long, and about
the thickness of a straw, much bent or twisted, either
simple or branched, with a remarkably knotty cha-
racter, owing to numerous circular depressions or
clefts, which give the whole an appearance of a mun-
ber of rings; and hence the term anaalated. It con-
sists of a central portion called meditallz'am, and an-
external portion called the cortical part. Each con-
tains emetina, but by far the greater portion exists in
the cortical. Of the 3 varieties of annulated ipecacuan,
the brown contains 16 per cent. of emetina, while
the red contains only 14¢ per cent.” The aarlalated
or amylaceoas ipecacuan, contains only 6 per cent.
of emetina, with 92 per cent. of starch. Emetina is
a white, inodorous, and nearly tasteless powder.
IRIDIUM, (Ir. 9868.) This metal is noticed in
our Introductory Essay, vol. i. p. 0.
IRON (Fe. 28) is more extensively diffused
throughout the crust of the earth, and in greater
abundance, than any other metal: indeed, it is
scarcely possible to analyse an inorganic body with-
out finding it: and its importance is equal to its
abundance, for there is no other substance which
possesses within itself so many valuable properties,
or is so well adapted to form the tools, machines, and
engines, which have assisted, and still continue to

maintain, the dominion of mind over matter. Admi-
rably adapted also to the wants of man is the position
of iron ore in the earth, for it is often found in imme-
diate connexion with the coal and the limestone flux
required for its reduction: “ an instance of arrange-
ment,” as Conybeare well remarks, “ so happily suited
to the purposes of human industry, that it can hardly '
be considered as recurring unnecessarily to final
causes, if we conceive that this distribution of the
rude materials of the earth was determined with a
view to the convenience of its inhabitants.”
SECTION I. —METALLURGICAL Hrs'ronr or Inon.
Iron was known at a very early period in man’s
history. l/Ve read in Gen. iv. 22, that Tubal Cain
was an instructor of every artificer in brass and z'ma,
and in many parts of the sacred record we have evi-
dence of the extensive use both of iron and steel.
Among the ancient Greeks bronze seems to have pre-
ceded the use of iron, and the term used to designate
the smith’s calling signified “ a worker in bronze,”
a term afterwards applied also to workers in iron.
Many passages in Homer show that iron was well
known in his time, and there can be no doubt that the
word m'b‘npos has been correctly translated into iron,
for in the Odyssey there is a simile commencing thus:
“As some smith or brazier plunges into, cold water
a loudly-hissing great hatchet or adze, tempering it,
for hence is the strength of iron,” &c.; thus proving
that the art of tempering steel was practised as it is
at present in the manufacture of cutting-tools, and
that the worker in iron or steel was called a brazier.
In later times, steel was abundant in Greece. ZEschy-
lus (born 4160 3.0.) includes all the countries on the
shores of the Black Sea under the general term
Scythia or Ohalybia. “ He speaks of the Chalybes
as Workers in iron, of Scythia as a land, ‘the mother
of iron 5’ and of the sword, as ‘ sharp iron, the bitter
appeaser of strife,’ ‘ the Pontic stranger born in fire ;’
and also as ‘the Chalybian stranger come out of
Scythia.’ From this time dates the use of the word
Clldlydé’, in Greek, as signifying steel of the best
quality; whence it passed unchanged into the Latin
language, and may at the present day be recognised
in our own, in the expression clzalybeate waters,
clzalybeate medicines, &c., in consequence of some
commercial transactions which took place more than
twenty-three centuries ago between Greece and a
country on the Black Sea.”1
The Romans had an early acquaintance with iron.
Diodorus Sicnlus mentions Ethalia (Elba) as being
celebrated, as it now is, for the richness and abun-
dance of its iron ores. Pliny the elder, after enu-
merating many of the uses of iron in his time, says,
“ Yea, in one word, we use it to all other necessary
uses of this life.” This writer refers to Spain as
being celebrated for its iron manufactures. But
although iron was well known to the Romans, it


(1) In Mr. Arthur Aikin’s “ Illustrations of Arts and Mann-
factures,” published in 1841, are four excellent papers, read before
the Society of Arts, entitled, “ The Antiquarian and Metallurgical
History of Iron.”
1: 9
Id
68
IRON;
appears from the evidence afi'orded by the excavations
of Pompeii and Herculaneum, that articles of. bronze
were in general use in the middle of the first century,
when those cities were overwhelmed. It is dilhcult
to imagine how bronze and iron should ever be con-
sidered as equally applicable to the same uses. “ In
all the Latin writers, fer/rum, iron, is the most com—
mon name for a sword, but the swords which have
been found in these towns are of bronze, as also are
the points of spears. Poll-axes and other sacrificing
instruments have been found of the same material:
even surgeons’ instruments, 410 in number, some with
cutting edges, and all of bronze, were discovered.”
The earliest method of smelting iron seems to have
been in furnaces erected on the summits of hills for
the sake of currents of air, the furnaces ~being per-
forated on all sides with holes, through which the air
was driven when the wind blew : the ore was in-
terstratified with charcoal, large quantities of which
were added from time to time, and the operation lasted
two or three days. Mungo Park, in his Travels in
Africa, describes one of these furnaces, which is pro-
bably a type of the ancient model. A furnace similar
to this was probably used by theancient Britons, who
are supposed to have obtained their knowledge of thev
art of smelting iron from the Phenicians, who traded
with them for tin. Strabo mentions iron as one of
the exports of Britain, so that it seems pretty evident,
that prior to the Roman invasion the Britons were
acquainted with the art of working iron: indeed, the
scythes, hooks, broadswords, and spears, with which
they opposed their invaders, are evidences of the fact.
Mr. Mushet, in his valuable “ Papers on Iron and
Steel,” remarks on the extreme slowness ‘of these
air-bloomeries. “ A long and continued cementation
of the ore in contact with the fuel was necessary to
dispose the metallic particles to unite. A too rapid
exposure to a high temperature would be apt to unite
a considerable portion of oxygen with the ore, which
in this way would acquire a considerable degree of
fusibilicty'i this would not only diminish the quantity
and quality of the iron, but retard the general opera-
tion. To render the quality of the iron homogeneous,
masses of iron ore would be used as nearly of one size
as possible, which would give rise to a rejection in
part of the small, or dust ore, generally the richest of
the vein. That this practice prevailed to a consider-
able extent in Gloucestershire, is evident from the
large quantities of small mice‘ found from time to
time in the old caverns or weeldons of the mountain
limestone formation. These acknowledged evils un-
doubtedly affected the economy and prosperity of the
trade, until some more fortunate or more ingenious
worker applied the bellows to the art of iron making,
which gave rise to. the blast-blowing, and occasioned
a great revolution and improvement in the fabrication
of iron.” '
When the Roman Conquest was secure the useful
arts were carried on in Britain to an extent before
unknown in the island. After the arrival of Adrian,
(AD. 120,) the fad-rice, orrgreat'military forge, was
established at Bath : and similar establishments were
formed in different parts of the country. The situation
of Bath was well adapted to such an establishment,
from its vicinity to the hills of Monmouthshire and
Gloucestershire, where iron ore and wood were plen-
tiful. There is abundant evidence of the industry of the
Romans in working the iron mines of Britain 1mtil
their final abandonment of the island about A.]). 409.
Immense beds of iron cinders have been discovered
in the Forest of Dean in Monmouthshire, in York-
shire, and other counties, among which have been-
found Roman coins and the remains of altars inscribed
to the god whov presided over iron. Many of these
heaps are called Dames’ cinders, from the idea, probably
a correct one, that during the-occupation of England
by the Danes they carried on the smelting of iron
extensively. From the rude method of smelting in
these early times, a portion only of the ore was
reduced, and it has been found profitable in modern
times to smelt these cinders over again. Mr. Mushet
states, that fornearly 200 years the blast-furnaces in
the Dean Forest used nearly one-half of the furnace
burden of': these slags or cinders, which were found
highly advantageous to mix “with the calcareous ores
of the district. 5‘
In‘ the interval between the Saxon and the Norman
conquest scarcely any notices of iron are to be found.
The Anglo-Saxons bestowed especial honour on the
best artificers of swords, arms, and armour. Glou-
cester was long celebrated for its iron forges, and it
is mentioned in Doomsday-book, that scarcely any
other tribute was required from that city than 36
dicars (of 10 bars each) of iron, and 100 iron rods
for nails or bolts for the use of the royal navy. From
the Conquest to the death of John, iron and steel.
were‘ imported from Germany and other countries,
the German “ merchants of the steel-yard” probably
deriving that title from the article imported by them,
and sold at a place called “the Steel Yard.” The
art of making defensive armour was during this period
carried to great perfection, and a smith or armourer
was attached to the establishment of every knight.
Wood-charcoal still continued to be used in smelt-
ing iron, so that the iron mines were all situated in
the wooded districts of England. Iron must have
been scarce, for in the 28th of Edward III. its ex-
portation was prohibited. Up to this time all articles
of iron were forged, the art of casting not having
been invented, and it has not been determined at what
time castings first came into use. It appears, how-
ever, that towards the end of 'Elizabeth’s reign, the
English first attempted to substitute iron for bronze
in the casting of cannon, but the art was probably
practised long before in the production of other
articles? .
During the lath and 15th centuries England was
supplied by Germany and Spain with various articles
in iron and steel. In. 14:83 the home manufacturers
complained of this to the Legislature, which led to the
passing- of an act prohibiting the importation of a
variety of articles which could be made at home.



(1) The technical word for ore.

(2) SeeScrivenors’s History of, the Iron Trade, 1841.
IRON.
69
' In ‘the reign of Elizabeth we find the ingenious
Camden lamenting the decay of our forests in conse-
quence of the extension of the iron trade. Several
attempts were made in this reign to lessen the con-
sumption of wood, and to limit the erection of iron-
works; and it was not until the scarcity of charcoal
had stopped many iron-works, that attempts were
made to smelt iron ore by means of pit coal. Prior
to the year 1272 coal had been wrought at Newcastle,
and large quantities of it continued to be exported
annually to Holland and the Low Countries for the
use of the smithy, but it was not thought profitable
to smelt by means of coal until Dud Dudley set the
example. The name of this person deserves to be en-
rolled 011 the same bright page as that which contains
the names of Brindley, Arkwright, Watt, and other
illustrious menwho have so greatly contributed to raise
England to her present high position as a manufac-
turing and commercial nation. It appears, from the
interesting account which he has left of his own pro-
ceedings, that in 1619, at the age of 20, he quitted
the University of Oxford in order to manage three
iron-works of his father’s in the chase of Pensnet in
Worcestershire. Wood having become scarce in the
neighbourhood, and pit coal abounding near the fur-
nace, he determined to make trial of it, and was so
successful, that he applied for a patent for his-inven-
tion, which was granted for 31 years. In- the year
after the date of the patent, Dudlcy’s iron-works
were destroyed by a great flood, “ to the joy of many
iron-masters, whose works escaped the flood, and who
had often disparaged the author’s inventions because
he sold good iron cheaper than they could afford it,
and which induced many of the iron-masters to com-
plain unto King James, averring that the iron was
not merchantable. As soon as the author had re-
paired his works and inventions, to his no small
charge, they so far prevailed with King James, that
the author was commanded, with all speed possible,
to send all sorts of bar-iron up to the town of Lon-
don, fit for making of muskets and carbines; and the
iron being so tried by artists and smiths, that the
iron-masters and iron-mongers were all silenced until
the 21st of King James.”
In this year, 162.41, was passed the justly celebrated
act for the abolition of monopolies, except patent
rights for 14: years to the first inventors of processes
or manufactures. Dudley’s patent was limited to this
term, and he says, that he “went on cheerfully, and
made annually great store of iron, good and mer-
chantable, and sold it at 12!. per ton. He also made
various cast-iron wares, such as brewing cisterns,
pots, mortars, &c., better and cheaper than any yet
were made in these nations with charcoal.” But so
slow are ordinary minds to adopt new ideas, or to
vary the ordinary routine of their proceedings, that
the iron-masters continued to oppose, and succeeded
in getting poor Dudley turned out of his iron-works.
How this was effected, would, he says, be “ over long
to relate ;” but we can well imagine the long course
of opposition, of petty annoyance and vexation, in-
fiicted by his rivals, to say nothing of positive wrongs,

of combinations among masters and men to oppose
a man who was adopting a process the value of which
they had not the sagacity to perceive. Dudley pro—
ceeded to Himley furnace in Stafi'ordshire, “ where he
made much iron with pit-coal; but wanting a forge to
make it into bars, was constrained for want of stock
to sell the pig-iron unto the charcoal iron-masters,
who did him much prejudice.” After this he erected
a large furnace, “ 27 feet square, all of stone,” at
Hascobridge, in Stafi'ordshire, “ where he made '7 tons
of iron per week, “the greatest quantity of pit-coal
iron that ever yet was made in Great Britain. Near
which furnace the author discovered many new coal
' mines ten yards thick, and iron mine under it, accord-
ing to other coal works; which coal works being
brought unto perfection, the author was, by force,
thrown out of them, and the bellows of his new
furnace and invention, by riotous persons, cut in
pieces, to his no small prejudice and loss of his in—
- vention of making of iron with pit—coal, 850. ; so that
being with law-suits and riots, wearied and disabled
to prosecute his art and invention at present, even
until the first patent was extinct.” Poor Dudley lost
most of his property, and was imprisoned for debt;
and when Cromwell came into power, he had the
mortification- of seeing a patent granted to one
Captain Buck, for making iron with pit-coal: he
states that Cromwell and many of his officers were
‘partners in the scheme, which, however, failed. At
the Restoration, Dudley presented a memorial to
Charles 11.; it is an exceedingly interesting document,
and contains a masterly epitome of the iron trade up
to the time of its composition. It appears strange
to us that the force of- such reasoning as the following
could be resisted, especially when the prize to be
gained by yielding to it was iron !' After stating that
God of his infinite goodness had bestowed upon ‘this
country abundance of iron, coal and lime, and that
the wood had long been exhausted, he proceeds
thus :-—“ Now, if the coals and ironstone so abound-
ing, were made right use of, we need not want iron
as we do; for. very many measures of ironstone are
placed together under the great ten yards thickness
of coal, and upon another thickness of coal, two
yards thick, not yet mentioned, called the bottom
coal, or heather coal, as if God had decreed the time
when and how these smiths should be supplied, and
this island also with iron; and most especially, that
this coal and ironstone should give the first and last
occasion for the invention of making iron with pit-coal,
no place being so fit’ for the invention to be perfected
in as this country, for the general good; whose lands
did formerly abound in forests, chases, parks, and
woods, but exhausted in these parts.”
Dudley does not seem to have been successful in
his application, and with him died, for a time, the art
of making iron with pit-coal. The art of converting
coal into coke was known and is described by
Dr. Plot, in his History of Staffordshire, published in
1686, who says, that it is “ fit for most other uses,
but for smelting, fining and refining of iron, it cannot
be brought to do, though attempted by the most
70
IRON.-
skilful and curious artists.” Our chemists at this
time were too much occupied in attempting to trans-
mute the baser metals into gold, to attend to the
apparently common-place and inglorious problem, how
to smelt iron with pit-coal.
It was not until 1713, that we hear of any further
attempts in this way, when Mr. Darby, of Colebrook
Dale, is referred to as smelting iron with pit-coal.
The process, however, must have been ill understood,
and little known, for in 1747, it is stated in the
Philosophical Transactions, as a Sort of curiosity, that
“ Mr. Ford, from iron ore and coal, both got in the
same dale, makes iron brittle or tough, as he pleases 5
there being cannon thus cast, so soft as to bear turn-
ing like wrought-iron.” . . .
’ Although the demand for iron was every year
rapidly increasing, the yield of our iron furnaces was
almost as rapidly diminishing. Instead of relying
upon our inexhaustible supply of coal and iron to
meet the demand, our ancestors imported vast quan-
tities of iron from Russia and Sweden. At length,
however, the steam-engine, under the guidance of
Watt, entered into the service of industry, and gave
such a stimulus to our great branches of manufac~
tures, that vast systems of iron machinery were being
constantly demanded. Then it was‘ that the coal
and the iron-stone were made to ‘act upon each other,
and the impulse once given, the manufacture advanced
with accelerated ynelocity ; and from 61,300 tons pro-
duced in 17 88, we have in 1851 the enormous
amount of 2,500,000 tons. -
While the change in fuel was being brought about,
the manufacture declined so rapidly, that in 1740, the
number of furnaces in England was 59, being only
three-fourths of their previous number, and the
annual produce was only 17,350 tons. As the use of
coke became understood, the manufacturerevived, so
that in 17 88 the number of tons of pig-iron produced
was 61,300, as already stated; in 1796, the quantity
was increased to 108,793 tons; in 1806 to 250,000
tons; in 1820, tov 380,000 tons; in 1827, to 65,41,500
tons; in 18415, to 1,250,000 tons; and in 1851, to
2,500,000 tons.1 In this year, the exports of pig-iron
were upwards of 1,200,000 tons, besides tin plates,
hardware, cutlery and machinery, bearing a total
value of $310,424,139.
Improvements in the smelting of iron have been
great and important, as will appear from the following
statement, of the average produce of each furnace
annually and weekly.
AIyNUALLY. WEEKLY.
' tons. ewt. qrs. tons. cwt.
1111740."..- ............ 294 1 i 5 '13
.796 2 0 15 6 .
1796’ ........ .. ............ .. 1,046 0 0 20 2
_ 2,460 0 0 47 6
‘5,3200 0 0 100 0
At thev present time, the ‘average weekly yield of
a furnace is from 110 to 120 tons of pig-iron; but

(1) Of this quantity '1}, was used in castings, the remainder in
malleable manufactures. To produce it required 7,000,000 tons of
ore, 2,700,000? tons ‘of ‘limestone, and 13,000,000 tons of coal.
_ From. 650,000 to 700,000 persons'are engaged in the manufacture.
Steam-power." is also largely used. ' .
.iron than the woodland districts had done.

in an-_,emergency, as much as 200 tons have been pro-
duced from one furnace inia week. At the-time we
write (May 1852), some of the Scotch and Welsh
furnaces are producing the latter quantity.
The locality of the manufacture has also been
affected by the change of fuel. In 17 40, Gloucester
was the largest iron producing county in Great
Britain._ Sussex had the greatest number of fur-
naces; there were a few in Kent, and a few in the
Midland Counties, and along the Welsh borders.
After the introduction of coke, the coal counties
assumed a far greater importance in connexion with
Shrop—
shire, Staffordshire, and South Wales became impor-
tant ; for some years past the greatest quantity of
iron has been produced in South Wales 5 although
Shropshire and Staffordshire have produced a superior
metal. Scotland also has competed ~~successfully in
the production of this all-important metal.
“ In whatever point of view the iron trade may be
considered with regard to this country,” says Mr.
Mushet, “the advantages derived from its progress
have been great; whether we consider it as having
cleared the country of vast tracts of wood, affording
at the same time an ample indemnification for the
labour bestowed—the consequent ‘improvement in
climate, and the spread of agriculture,—.-—-as having
placed us at the, head of the manufacturing countries
of Europa—as affording us at all times a plentiful
supply for the construction of every species of m a-
chinery,—-or, as having been a source of wealth to
many individuals, and, at the same time, affording a
competent recompense for the labour of a number of
our fellow—creatures.”
Sne'rron II.-IRoN AND ITS CoMroUNns.
Iron is employed in the arts in three different-
states,——as oracle or east-iron,‘ as steel, and as wrong/it-
z'ron, the differences depending upon the relative
amounts of carbon with which the metal is combined.-
Cast-iron contains a larger proportion’ of carbon than
steel, and steel more than wrought or malleable iron,
which ought to be quite free from carbon. In
practice, however, this is never found to be the case,
although the best malleable iron retains only a very
minute portion of carbon. The iron of commerce is
also contaminated with traces of silicium, sulphur, and
phosphorus, the. presence of which greatly influences
the quality of the metal. .
Pure iron may be obtained by, introducing into a
Hessian crucible a parts ‘of fine iron wire out small,
and 1 part of black oxide of iron: this is to ' be
covered with a mixture of white sand, lime, and
carbonate of potash the proportions used for glass
making, or pulverized hard glass may itself be used,
and a cover being closely, applied, the crucible is to be
subjected to an ‘intense white heat. A button of
pure metal is thus obtained, the traces of carbon
and silicon present in the wire having been removed
by the oxygen of _ the oxide, ‘and combining with the
vitreous flux form _-a slag. Pure metallic’ iron may
also be obtained ‘bypassing, hydrogen gas over one.
IRON.
71--
of the oxides of the metal contained in a tube of por-
celain or hard glass heated ‘to dull redness. The
reduced metal will be in a spongy state, and by
exposure to the air will absorb oxygen so greedily,
as to take fire and become converted into a sesqui-
oxide 5 but if the reduction be made at ahigh tempera-
ture, the particles cohere, and the metal does not
ignite on exposure to the air.
Pure iron has a white or bluish grey colour, and
acquires a brilliant surface by polishing. Its sp.
gr. is 7 '8, and its crystalline form is probably the
cube. The texture of commercial iron varies accord-
ing to its mode of preparation. I’ure iron, which has
been drawn out under the hammer in ‘all directions,
has a finely granular structure, but when rolled
into long bars, as usually sent into the market, the
texture is fibrous in the direction of the length. The
fibres may be made evident by the fracture of a bar of
iron under tension, or by acting upon it with dilute
muriatic acid. Upon the perfection of this fibre
much of the strength and value of iron depends,
although by skilful management this silly character
may be imparted to common varieties of the metal.
The fibrous character is not, however, necessarily
permanent, for after a time the metal has been found
to assume a crystalline appearance, especially when
subjected to constant vibration, as in the tension rods
of suspension bridges, the axles of locomotives and
of railway wagons, 820.‘
Iron is the most tenacious of all the metals, a wire
of gibrth inch in diameter bearing a weight of 60 lbs.
It requires the strongest heat of a wind furnace to
fuse it, but when combined with a small proportion
of carbon it fuses at a much lower temperature.
Before it becomes liquid, or when liquid before it
becomes solid, iron passes through a soft or pasty
condition, and-hence crystallizes with dilficulty; but
when slowly cooled in large masses, indications of a
cubical crystallization are obtained. At a full red-
heat iron may be hammered into ‘any form, and at a
white heat, two pieces pressed or hammered together
cohere: but in order that, this operation, which is
termed welding, may be successful, the surfaces must
be in the metallic state, free from oxide; but as the
oxygen of the air combines rapidly with iron heated
to the welding point, it is usual to sprinkle a little
sand over the heated metal, and this combiningwith the
superficial film of oxide forms a fusible silicate, which
forms a kind of varnish, and protects the metal from
the air. On taking the bars out of the fire this

(1) A few years ago Mr. Charles Hood brought before thé Insti-
tution of Civil Engineers some interesting facts respecting the'
conversion of fibrous into crystalline iron. According to him,
the tough and fibrous character of wrought-iron is entirely pro-
duced by art, and there is a constant tendency in such iron, under
certain circumstances, ‘to return to the crystallized state, which
state is not necessarily dependent upon time for its development,
but is determined by other causes, the chief of which is vibration.
H eat, within certain limits, though greatly assisting the rapidity
of the change, is certainly not essential to it; but magnetism, in-
duced either by percussion or otherwise, is necessary to the
change. It was shown by specimens, that in the same rod or bar
of wrought-iron, the crystallization is far more extensive in those
parts most exposed to vibration, In the parts'not so exposed, the
texture remained fibrous.

silicate is by a rapid motion shaken oif, and clean
metallic surfaces can thus be brought into contact, or
the silicate is forced out by the pressure applied in
uniting them,
Iron, nickel, and cobalt, are the only metals which
are evidently magnetic at ordinary temperatures. A
piece of pure iron immediately becomes magnetic in
the vicinity of a magnet, but it loses all magnetic
properties as soon as the magnet is removed to a
distance. Magnetism is developed in steel more
slowly, but is retained more permanently ; and a bar
of steel rubbed by a magnet becomes itself a perma-
nent magnet. The magnetic properties of iron di-
minish rapidly as the temperature rises; a mass of iron
heated to redness has no action on the magnetic
needle, but it regains its magnetic properties in
cooling.
Iron does not oxidise in dry air, nor even in dry
oxygen, at common temperatures; but in moist air it
becomes covered with a scaly coating of black oxide
or rust. The presence of carbonic acid in air greatly
assists the operation, for the iron becoming changed
into the carbonate of the protoxide absorbs a new
portion of oxygen and is thus transformed into the
hydrate of the peroxide of iron. The carbonic acid
disengaged facilitates the oxidation of a new portion
of metallic iron. When once iron has begun to rust
at one point of its surface the rust spreads rapidly
round this point in consequence of a galvanic action,
which accelerates the oxidation. 'llre small spot of
rust forms the two elements of a voltaic pile, in which
the iron is positive, and thus acquires for oxygen an
affinity suificiently strong to decompose the moisture
of the air, hydrogen being set free. Rust also con-
tains small portions of'ammonia, the odour of which
becomes evident by heating it with potash. Am-
monia, which consists of hydrogen and nitrogen, is
formed when these two elements come into contact
in a liquid, in what is called the nascent slate, that is,
in the very act of separating from a body under
decomposition. Now the moisture of the air con-
taining a portion of air, and consequently a portion
of nitrogen in solution, this moisture coming in
contact with rust of iron, is decomposed, and the
hydrogen and nitrogen which are set free at the same
moment combine to form ammonia. The ammonia is
retained by the peroxide of iron, which acts towards
it as a weak acid would do.2 ‘Iron becomes soon
rusty in pure water, but not in water containing
minute portions of carbonate of soda or of potash.
It is common now to preserve iron from rust by cost .
ing it with a thin layer of zinc, forming what is
called galvanised iron, by a process explained under
AMALGAM.
When iron is heated to redness, in contact with
the air, a film of oxide forms, which falls off under

(2) It was formerly supposed that when a. steel or iron weapon,
on which certain stains were observed, was heated in contact with
potash, and emitted an ammoniacal odour, that this was sufiicient
evidence that such stains were produced by blood. Such evidence
as this has been produced in criminal trials, but we now see that
the exposure of an iron or steel blade to moist air is suflicicnt for
the production of ammonia.
'72
IRON.
the" hammer. When sparks are struck by the old
fashioned flint and steel, minute portions’ of the metal
are struck off, and being heated by- the friction of the
flint the oxygen of the air seizes them, and they enter
into combustion. If a piece of iron be struck with
a flint over a sheet-of white paper, it will soon be
covered with small black grains capable of being
attracted by‘ the magnet, and whichare in fact small
globules of magnetic oxide of iron.
~ Four compounds of iron and oxygen'are commonly
described. The first is the protozcide (Fe O) which
acts-as a powerful vbase completely neutralizing acids.
It is seldom met with in a- separate state, in con-
sequence of its tendency to-absorb oxygen and pass
into the sesquioxide: its soluble salts have usually a
delicate pale ‘green; colour, and- a nauseous metallic
taste. The peroxide (Fe2 03) is a feeble base, and may
be prepared by precipitating a solution of persulphate
or perchloride of iron by excess of ammonia, and wash-
ing, drying and igniting the yellowish brown hydrate
thus produced. In the state of powder this oxide has
a full red colour and ‘is used as a pigment, for which
purpose it is prepared by calcining the protosulphate,
the tint varying with the " temperature. This oxide
dissolves in acids, forming a series of reddish salts.
It is not acted on by the magnet. The bloc/e oxide
(Feg O4), also known as the magnetic oxide or the‘
Zodestoize, does not form salts. .Ferric acid (FeOs) is
prepared by heating a mixture of pure peroxide of
iron with 41 parts of d'ry-nitre'; by subsequent treat-
ment a solution of ferrate of potash is formed, which
is not permanent, but when baryta is added a deep
crimson insoluble ferrate of that base is formed, which
is permanent.
By dissolving iron in hydrochloric acid, green
crystals ‘of protoofiloride (Fe Cl) may beformed, and
by dissolving vperoxide of ‘iron in the same'acid the
red hydrated crystals of the sesquichloride (Fe2013) may
be produced. The protiodide (Fe-I), important in
medicine, is formed by digesting iodine with water
and metallic iron. 'There are several compounds of
iron and sulphur. The protosuZp/mi'et (Fe S) is
formed by bringing a white hot bar of iron in contact
with sulphur; but the usual method is to project
into 'a red hot crucible * a mixture of 2% parts of
sulphur, and 4: parts of iron filings, excluding the air
as much as possible. :It is a blackish brittle substance
attracted by the magnet. The bisuZp/zuret (Fe S2)
will be noticed among the ores of iron.
- Compounds of iron with phosphorus, carbon and
silicon exist; the earbiiret'in cast-iron and steel, which
' it :renders .more fusible; the silicon compound is also
found in cast-iron, which it probably renders brittle, as
does also phosphorus, the presence of which is sup-
posed toiconfer the property technically called cold-
s/zort, ‘while the presence ‘e of ‘sulphur renders iron
kov't-s/lort.
' .P’POZOSZtZjIddiGIQfiTOiZ’OfGi'GMZ Vitriol, FeO, $030+
7,.HO. important salt may be obtained by dis-
solvl'mg' iron in ‘dilute sulphuric acid; but it is usually
prepared "on a large scale from iron pyrites,'as will be
noticed presently; ' " Sulphate of iron slowly efioresces

and becomes peroxidiz'ed in ‘the air; it is soluble in
about twiceits weight of cold water. The pei'sulptate,
Fe20-3, 3803, does not crystallize. The protonitmte
FeO, N05, is not a very stable compound; the
pernitmte is formed by pouring nitric acid, slightly
diluted, upon iron; it is a deep red liquid used in
dyeing. The protoodrtonate, Fe 0, C02, is formed by
mixing solutions of the protosalts of iron and alkaline
carbonates: it exists in the common clay iron-stone,
and is often found in mineral waters.
SECTION TIL—NATIVE AND Mn'rnonlo Inon, AND
Inon Onns.
Native iron is of rare occurrence: it has been found
in Saxony and elsewhere, forming the centres of sta-
lactiform masses of brown hematite. These metallic
kernels appear to have been produced by the decom-
position of a portion of the oxide in which they are
imbedded, a- change which may have been brought
about by electro-chemical agency.1 Native iron is
also produced by the spontaneous ignition of seams
of coal in the neighbourhood of ferruginous deposits,
producing small button ingots with a finely striated
surface; they are very hard and fine grained, and are
known by the name of native steel. Large masses of
metallic iron exist in different parts of the world, and
other similar masses have been observed to fall from
the atmosphere. These meteorites differ in structure
and composition from native iron: they always con-
tain nickel, which is not found in the ores of iron,
and they are covered with a kind of black siliceous
varnish which protects them from the air; when this
is removed the metal easily oxidises. Some of the
masses of meteoric iron have been used by the inhabi-
tants of the countries where they fell, in making
knives, spears, and other instruments. There is a
mass in South America estimated at 30,000 lbs.
weight ; one in Siberia, 1,600 lbs. ; and one at Agram,
in Croatia, which fell from the sky in 1750, in the
presence of many witnesses. Numerous ae'rolites have
at different times fallen from the atmosphere; they
contain other substances in addition to iron. A stone,
which fell at Chateau Renard on the 12th June, 184.41,
was found, by M. Dufrénoy, to contain per cent.
silica, 30‘13; alumina, 3'82 ; magnesia, 38'13; lime,
0'14 ;- oxide of iron,'29'4l4r; oxide of manganese, a
trace; potash, 0'27 ; soda, 0'86 ; sulphur, 0'39; iron,
7'70; nickel, 155.
The ores of iron are very numerous, and we can
only refer to a few of the most important in ametal-
lurgical point of view.
One of the most universally diffused ores of iron
is the magnetic: it occurs in granite, gneiss, mica
slate, clay-slate, syenite, hornblende, and chlorite ;
also in the limestone formations. Nearly all the
(1) Mr. John Arthur Philiips, in his recently published Manual
of M etaZlurgy,-—an excellent guide-book to all persons interested
in the chemistry .of the-metalsr—explains this change by suppos-
ing, “ that the whole or a Portion‘ of the iron formerly existed in
the form 0f iron PYIitBS, '(bis'fllphuret of iron,) which, becoming
oxidised, not only produced a certain amount of the soluble
sulphate of iron, but also generated by chemical action an electric
current of sufficient power-to precipitate a part of the iron in the
metallic form.” .

IRON.
'73
Swedish iron is obtained from this ore. It is also
abundant in the Island of Elba and in the United
States of America. The primitive form of magnetic
iron ore is a cube, but it often occurs in octahedrons
and dodecahedrons. Its cleavage is often parallel to
the faces of the octahedron. It is brittle, of an iron-
black colour, and leaves a black streak. Density, 50
to 51. It is strongly attracted by the magnet, and
sometimes possesses independent polarity. It contains
iron, 71'’? 8, and oxygen, 28%; or peroxide of iron,
69, and protoxide, 81.
Specni‘ikr iron ,- Reel Hematite—The crystals of this
ore are generally complex modifications of the rhom-
bohedron, of a dark steel-grey colour, opaque except
in very thin laminae, when they are transparent, and
of a deep blood—red tinge. It leaves a reddish streak,
and the density varies from 4:8 to 5'3. Pure specu-
lar iron consists solely of peroxide of iron.
There are several varieties of red iron ore. Fibrous
iron, or red hematite, occurs in fibrous reniform masses.
When there are no indications of columnar structure
it is termed compact, and if mixed with. argillaceous
matter, it is known as real oo/zre. When specular iron
has a foliated structure, it is called niieaceons. Spe-
cular iron ore is also called oligisiio iron, iron glance,
and r/zornoo/zedrril iron. Jasperg/ Jlag/ iron ore is of
a brownish red colour, with a large flat conchoidal
fracture: when it occurs in small flattened grains it
is called Zeniionlar clay iron.
The purer varieties of this ore occur in the older
formations : the argillaceous ores are usually met
with in secondary rocks. The Island of Elba fur-
nishes beautifully crystallized specimens: brilliant
crystals are also found in the fissures of volcanic
districts.
Red hematite is found in reniform masses in Corn-
wall, at Ulverstone in Lancashire, and other places.
[See HEMATITE, Fig. 1117 .] This ore, when ground
to powder, is used as a pigment, and also for polish-
ing metals.
The various ores of the peroxide are of great im-
portance as a source of iron, although they do not
yield so large a percentage of metal as the magnetic
oxide: the specular varieties are also somewhat
refractory in the furnace; but by a proper mixture
with other ores they yield an excellent iron.
Brown iron ore is, as its name implies, of a brown-
p.’ ish colour, and it affords when crushed a yellow
powder.
Its density varies from 3'8 to 4:2. When
pure it yields 55 per cent. of metallic iron. It is a
hydrated peroxide, chiefly found in sedimentary rocks.
Its forms are often pseudomorphic,1 and these may be
due to the decomposition of iron pyrites when it
assumes the cube or octahedron. It also occurs in
rhombohedrons from the substitution of carbonate
of iron, as also in the moulds left by the decompo-

(l) A pseudomorphous crystal, (from cases, false, and popqh‘], a
form,) is one that has a form which is not known in the species to
which the substance belongs. There are many causes for pseudo-
morphism, as when a cavity left empty by a decomposed crystal,
is refilled by another species by infiltration, and the new mineral
assumes the external form of the original mineral. Crystals may
also be incrusted over by other minerals.

sition of shells and madrepores, the shapes of which
are assumed by the mineral. It also forms stalactites
and hollow reniform masses. Pen-iron is one of its
forms, found in the oolitic formations. When mixed
with aluminous matter it acquiressa soft texture, and
is known as yellow ochre. '
This ore.is in some countries, France, for example,
the most abundant source of iron; and when washed
to separate the lighter impurities, it yields an excel-
lent material for the manufacture of iron. But when
beds of oolitic iron are found to alternate with
calcareous deposits, the metal produoedis eoZeZ-s/iori,
in consequence of the phosphorus derived from the
organic matter of the chalk.
Iron pyrites, or bisulphuret of iron, Fe S2, contain-
ing, iron, 415'? ll. per cent, and sulphur, 54'26‘,‘ crystal~
lizes = in‘ ‘the cubic system, frequently in pentagonal
dodecahedrons, also in octahedrons and cubes more
or less modified. The colour is bronze-yellow, with
a metalhc lustre; the streak, brownish-black; sp. gr.
4t'8 to 5'1: it is brittle, and strikes fire with steel,
whence the name pyrites. The cleavage is parallel
to the faces of the cube and octahedron. It occurs
in small cubical crystals, Fig. 1216, in veins, and in
various slate-rocks
and coal-fields, and
in globular concre-
tions in indurated
clay and chalk. It
also accompanies
the ores of all the
other metals, and
in many cases re-
places the remains
of animal and vege-
table forms. The crystals from Elba are very fine:
very large cubes are also obtained from Cornwall,
and large perfect octahedrons from Sweden. It is
also found in many of the coal-fields, where, by its
oxidation and conversion into sulphate of iron, the
temperature is in some cases so much raised as to
ignite the coal.
Iron pyrites is not used as a source of metallic
iron; but is frequently employed as a source of sul-
phur in the manufacture of alum and sulphuric acid.
[See ALUM—SULPHUBIC Acrn]
White-iron pyrites has the same composition as the
above, but crystallizes in forms derived from the right
rhombic prism. It often occurs in radiated crystal-
lized masses, called eoe/eseorno jig/rites. It occurs in
most of our mineral districts. There is also a mag-
netic iron pyrites, and an arsenieal iron jig/rites.
We must also refer to chrome-iron, which occurs so
abundantly in the Shetland Islands, and is used for
making chromate and bichromate of potash; and to
inngsz‘ai‘e of iron—Woifram—-which has been lately
employed for making tungstate of lead, to be used as
a pigment instead of the white-lead now in use.
The ore from which the greater portion of the iron
manufactured in this country is obtained, is the ear-
oonaie. It occurs in rhombohedrons and six-sided
prisms, resembling carbonate of lime: also in glo~


Fig. 1216.
74
IRON.
bular concretions, or lenticular masses. When pure,
it consists of protoxidc of iron 6137 per cent., and
carbonic acid 3363. It is known by the various
names of Siderz'te, Sperry; z'rorz, Spat/rose iron, Brown
spar, &c. Sparry-carbonate of iron, Fig. 1217, often
accompanies
other metallic
ores, such as
those of lead
or copper. In
Styria and Car-
inthia the beds
occurin gneiss ;
in the Hartz, in
grey - wacke;
- . but the English
Fig. 121?. deposits are
confined to the coal-formation: it usually occurs in
horizontal strata, subject, however, to the same in»
clination as the other strata which it accompanies.
It is generally found imbedded in schistous clay, more
or less compact, which moulders away when exposed
to the air. Hence its well-known name of clay 2'7'022-
stone. It is of grey, blue, brown, or black colours,
with sp. gr. from 2'8 to 3'5, and hardness from 35
to 4'5. It occurs, as already stated, chiefly in slate,
clay, or marls, in layers or nodular masses, often
containing fossil, plants, or other organic bodies, which
seem to have attracted the carbonate of iron. In
these nodules, crystals of siderite, calc— spar, celestine,
barytes, quartz, pyrites, blende, and galena often
occur. This variety is found occasionally in the trans-
ition rocks, but especially in the coal formation of
Britain, Belgium, and Silesia in vast abundance. It
is more rare in the oolite and chalk in Northern
Germany, and England; and in the brown coal of
Radnitz in Bohemia, and other places, frequently forms
petrifactions of wood. The ironstone is met with
under two different forms: in regularly connected
strata, called Zumds, and in strata of detached stone,
formed in distinct masses, from the size of a small
bullet to that of lumps of several hundred pounds
weight. “That is called Mack-band, ‘or carémzaceous
ironstone, is also a carbonate of iron, containing car-
bonaceous matter in addition to the ordinary earthy
substances found in all argillaceous ironstones. The
difference between black-band and clay ironstone will
be seen from the analysis of varieties of the two.
The carbonaceous matter in the black~band varieties,
Nos. 1 to 5, materially assists in the reduction of the
ores. Mr. Mushet says, in referring to this ore, that
instead of 20, 25 or 30 cwt. of limestone formerly
used to make a ton of iron, the black band only re-
quires 6, '7, or 8 cwt. This arises from the extreme
richness of the ore when roasted, and from the small
quantity of earthy matter contained in it, which ren—
ders the operation of smelting the black—band with hot
blast more like the'melting of iron than the smelting
of an ore. When properly roasted, itsrichness ranges
from 60 to 70 per cwt.,‘so that little more than 1% ton
is required to make a ton of pig-iron; and as 1 ton of
coal will smelt 1 ton of roasted ore, it is evident that



when the black band is used alone 35 cut. of raw
coal will produce 1 ton of good grey pig-iron.
The following is the composition of the celebrated
Black-band, (Nos. 1 to 5,) and other argillaceous iron
ores of Scotland and Wales.


s é‘ 5'3: a a
s s e 5 -‘~‘ 2
93 g :3 0-? O
s a s ‘=3 s = ii
a" e E a g s
8 <5’ 63" as
1- 70-0 23-0 7 01 33-7' Black Band, Lanarkshire.
2. 5104 22-16 26'80 24'6 Cwan Avon bed, S. Wales.
. . . . . Maesteg Valley, Upper bed,
3. 63 9 10 0 26 1 30 7 Upper division.
4. 79-9 6'6 135 38-5 Ditto, Lower division.
. . . _ Beaufort Ponty pool, 4 inch
5. 795 164 41 384 { band.’
6. 86'0 140 415 Ystradgunlas, Upper vein.
7. 72'4 27'6 34‘9 Ditto, another bed.
8. 75-4 24'6 36'4 Pendaren, Red vein.
9. 60'9 39'1 29'4- Aberfergwm, Nodules.
10. 555 44 5 26'6 Pendaren, Jack vein.


The different kinds of ironstone are known by
various local names, many of which are given by
Mr. S. H. Blackwell, in his catalogue of the series of
iron ores contributed by him to the Great Exhibition,
and refer ‘ed to in our Introductory Essay, p. lxxxvi.
From this instructive list we gather the following
particulars respecting the iron—making districts of
England and Wales.
South Wales is the most important iron-making
district in the world. Its coal-field extends over an
area of upwards of 800 miles, and from its extent,
and the varied character of its numerous beds of coal,
and its measures of ironstone and black-band, it may
be considered as the most important of all our coal-
fields. The number of furnaces now in blast is 14.3,
averaging about 100 tons of iron each per week: or
a gross annual production of 700,000 tons, and re-
quiring 2,000,000 tons of ironstone, which is princi-
pally furnished from this coal-field. The annual
production of coal is estimated at from 5 to 6 million
tons. In 1796, the annual production of iron in South
Wales was 341,011 tons; and in 1823, 182,325 tons ;
since which time the production has been more than
trebled. In 1851 it was 750,000 tons.
The production of iron in North Wales is very
limited: the coal-seams are thin, but good. in quality,
and the ironstones, although lean, furnish .very good
iron. -
In Shropshire, the annual production of iron is
about 90,000 tons. The quality is very good. This
field was one of the first important iron-making
districts of the kingdom ,but from its limited ex-
tent the production has not increased for a long
period. -
The Dudley division of the South Staffordshire and
Worcestershire coal-field is principally celebrated for
its ten-yard or thick coal. When undisturbed by
faults, and of average quality, this bed of coal, with
the associated thin coals and ironstones, is worth at

(1) This includes silica, alumina, and a trace of lime.
IRON.
‘i5
' equal number and extent of iron-measures.
least 1,0001. per acre. The quality of the iron is very
superior. The 62256222 and White ironstones are the
principal ironstones of this district. The Gubbin
measures average about 1,500 tons per acre; the
White ironstone varies both in quantity and rich»
ness, it yields from 1,000 to occasionally 3,000 tons
per acre 5 but 1,500 tons may be taken as about the
average.
In the Wolverhampton district the iron occupies
a position in the general coal series below the thick
coal of the Dudley district, and attains a much greater
thickness and importance than at Dudley. The iron-
stones are all of good quality, averaging from 30 to
35 per cent. of metal. From the low cost at which
they are generally raised, the number and variety of
the measures of coal and ironstone contained in so
small a space of ground, and the superior quality of
the iron produced, the Wblverhampton division of the
South Stafii'ordshire coal-field may be considered as
one of the most important, in proportion to its area,
of any of our iron-making districts.
The annual production of iron in South Stafford-
shire and "Worcestershire is nearly 600,000 tons. It
may be regarded as the second iron-making district
in the kingdom; for although the production of pig-
iron in Scotland is equal to that of this district, yet
it far surpasses Scotland in the manufacture of
wrought-iron; while the superior quality produced
also gives it pre-eminence over that of Wales.
North Stafi’ordshire produces only about 55,000
tons of iron, but it is of great importance from the
vast quantities of ironstone which it contains, and
the large quantities which it sends to the South Staf-
fordshire and the North Welsh iron districts. No
other known coal-field contains anything like an
In con-
sequence of so large a proportion of the cheapest
worked ironstone measures being black-band or car-
bonaceous, and also from the inferior quality of its
coals, the iron of this district is inferior.
In the northern district of Yorkshire the annual
production of iron is about 25,000 tons, and the
quality very superior. The southern district produces
about 20,000 tons.
The annual production in Derbyshire is about
60,000 tons. Many of the beds of ironstone lie in
such a thickness of measure as only to be workable
to advantage by open-work or bell-pits, in which
case the produce per acre is often very large ; in one
case it is 6,000, and in another 8,000 tons per acre.
N orthumberland, Cumberland, and Durham pro-
duce about 90,000 tons per annum. The iron~works
are increasing in importance, the cost of fuel being.
so low, as to admit of ores being brought from many
different localities. The black-bands of Scotland and
of Haydon Bridge, the brown hematites and white
carbonates of Alston and Weardale, and the argilla-
ceous ironstones of the has of Whitby and Middles-
borough, are all used in the iron-works of this
district. The brown hematites are found associated
in very large masses with the lead veins of this
district, and they sometimes occur in distinct and

regular beds. They contain from 20 to 410 per cent
of iron. In some cases they exist as riders to the
vein 5 in others, they form its entire thickness, which
is occasionally 20, 30, and even 50 yards.
The. production ‘of iron in the Lancashire and
West Cumberland district is verylimited, it being‘
confined to the Cleator Works, and one or‘two small
charcoal works in the Ulverstone district. The
quality of the latter, charcoal being used as the fuel,
is very superior, and the produce commands the
highest prices, as it combines with the fluidity of
cast iron a certain malleability, especially after careful
annealing. The iron of the Cleator works is. smelted
with .coal, and is of superior quality, although not
equal to the other. The ore both of the Whitehaven
and the Ulverstone and Furness districts is exten-
sively raised for shipment to the iron-works of York-
shire, Staffordshire, and North and South Wales.’
In quality these ores may be considered as the finest
in the kingdom 5 they contain from 60 to 65 per cent.
of iron. They are found both as veins traversing
the beds of the mountain limestone formation, trans-
versely to the lines of stratification, and also as beds
more or less regular. The former is the general-
character of the Ulverstone and Furness ores; while
at Whitehaven there are, at least, two beds of irre-
gular thickness, but with clearly defined floors and
roofs, and often subdivided by regular partings.
These beds are occasionally 20 or 30 feet thick.
They lie beneath and close to the coal measures,
which both furnish the necessary fuel, and also
important beds of argillaceous ironstone for ad-
mixture. '
The Forest of Dean produces every year about
30,000 tons of iron. The ores are carboniferous or
mountain limestone ores lying beneath the coal
measures, which are not here productive of argilla-
ceous ironstones, as in the other principal coal-fields
of the kingdom. There is also a bed of ore in the
millstone-grit measures. Thev limestone ore is ar-
ranged rather in a series of chambers than in a regular
bed. These chambers are in some places of great
extent, andcontain many thousand tons of ore, which
is generally raised at low cost, no timbering or sup-
ports for the roof being required.- The iron made"
from this ore is of a red short nature, and is espe-
cially celebrated for the manufacture of tin plates.
It commands a high price, and is extensively shipped
to South Wales. It yields from 30 to 4.0 per cent of
iron. ' -
The micaceous iron ores, and the magnetic oxides-
of Dartmoor, &c., are only just beginning to be
known. They produce a superior iron, adapted to
the manufacture of the finest steel.
In the Island of Anglesea, Tremadoc, Carnarvon,
and other localities round the North Welsh coast, are
ores of inferior quality, but lying in large masses;
they can be raised at trifling expense.
In some parts of Somersetshire, Gloucestershire,
8m. hematitic. conglomerates are found at the base
of the new red sandstone. Their character as
workable ores is very variable, being mixed up with
76
IRON.
so much extraneous material as to be almost worth-
less; but in some cases they exist in regular beds,
and contain so large a portion of hematite as to be of
importance.
The clay ironstones of the has are only just
beginning to be added to our iron-making resources.
They furnish an example of the unexpected develop-
ment of natural ‘wealth, arising from the facilities
afforded by railroads. ‘Ironstone is raised at a cheap
rate along the outcrop of the beds, on the coast
from Whitby to Scarborough. An important bed
has lately been opened at Middlesborough. Mr.
Blackwell has recently shown the vast extent and
importance of the silicious ironstone from the oolite
near Northampton.
The greensand of Sussex, which, in consequence
of the exhaustion of our forests, has long ceased to
yield ironstone to our furnaces, may, in consequence
of the facilities of transit offered by railroads, again
be called upon to yield supplies of this important
ore. Scotland in the year 1851 produced 7-7 5,000
tons of iron.1
Snorion IV.-—PnEPAnArIon on THE Onn AND FUEL
ron Snnnrrnc.
Iron ores are not sufficiently valuable to allow of
the crushing, stamping, washing, and other processes
which precede the reduction of copper, tin, and other
ores. They are usually roasted for the purpose of
expelling water and carbonic acid, and producing
that porous condition which is favourable to the
smelting process. The argillaceous carbonate, or
clay ironstone of the coal measures, which, as already
stated, is the chief source of the iron of this country,
and produces from 30 to 33 per. cent. of pig iron,
loses by roasting from 25 to 30 parts in every 100.
The loss consists chiefly of water and carbonic acid.
The usual method of roasting the ironstone is in
heaps, for which purpose a piece of ground is levelled
and covered with a layer of coal, from 6 to 8 inches
thick. The pieces of ironstone, as near the same
size as possible, are arranged upon this, to the height
of about 2 feet. This surface is levelled by intro-
ducing small pieces of ironstone in the spaces left by
the larger pieces. Upon this small coals are cast in
a layer of about 2 inches. Ironstone is then piled
up so as to form‘a wedge-shaped heap, and the hole
is lastly covered with small coal. The usual height
of such a heap is 6 or '7 feet, and its .breadth at the
bottom from 15 to 20 feet. The pile is lighted by
applying coals to ‘the ground ‘ stratum at the wind-
ward end, and ‘after having burned to a certain
distance, the pile is prolonged in the opposite direc-
tion. The fire creeps slowly along-gradually igniting
the ,whole ‘heap from the bottom to the top. When
the coals are all burnt out, the pile gradually cools,
andin about~ a month from thecommencement of the .
operation the ore is fit for the furnace.
The roasting of the ore is also frequently carried
on .in furnaces resembling lime-kilns. In a hilly
(1)'The methods of conducting the assay and analysis of iron
ores are clearly stated in Mr. Phillips’s Manual of Metallurgy.

1
district, such as that of Oolebrook Dale, they are
built of the form shown in Fig. 1218, by the side of
a hill, so that the mouth of the furnaces may be on








'-
""-r'~~\.-»__a-
w .




C
'


1,, I ,2! .
\\ 'eligffl’em ‘
\\ \ l" “M; U! ‘ W
0 r w
\
nu. _ - . *-
,_-—_~‘ _ .w“?f~‘
_....._.._
Fig. 1218. noxs'rmc IN KILNS. (Colebrook Dale.)
a level with the mouth of the pit, and the ore, as it
is raised, is wheeled along a railroad, and emptied
into them. The kilns are entirely filled with iron-
stone, except a stratum of coals at the bottom; and
when sufficiently roasted the register is closed, and
the whole allowed to cool.
Blacloband ironstone contains a considerable pro-
portion of bitumen, in which case, when once ignited,
it will continue to burn for a long time. Those ores
which do not contain any combustible matter require
during the roasting a small addition of coal dust.
Hence the proportion of coal required for calcining
clay ironstone varies from 5 to 20 per cent, depending
on the proportion of bituminous matter.
The coal used in the reduction of the ore is, to
a great extent, coded. This operation is performed
upon a flat oblong or circular surface, called a heart/z,
which is prepared by beating and puddling over
with clay. The coal is arranged on the hearth in
pieces, regularly inclining to each other, each piece
being placed on its sharpest angle, so that as small a


ire-L .
,K, -.~——— _
a‘ 1 1 m ...,, _______,_' =1"
{ill a‘ s. _
_I-_\\\\. z - _ rim
I I ll
‘ J ‘ W
‘that?
Fig. 1219. COKE nears NEAR DUDLEY.
surface {as possible may touch the ground ; by which
means spaces are preserved for the admission of air,
and for the swelling of the coals under the heat. In
building the pile, a number of flue holes are made,
Inon.
77
extending along the ground, and terminating in ver-
tical shafts in the centre. The heap is ignited by
putting burning fuel into these vents, which are then
stopped by small pieces of coal, to prevent the fire
from ascending, and to cause it to creep along the
bottom, where the draught is freest. When the fires
of the different vents meet, the combustion gradually
rises and bursts forth on all sides. Soon after the
smoke has ceased, the fire is covered up with the
dust and ashes of former burnings, beginning at the
base and gradually heaping it up to the top. From
Zl0 to 100 tons of coal are coked in one hearth. The
time for coking depends upon the quality of the coal
and the state of the weather. The combustion of
the volatile matters may be complete, and the heap
be covered over, in from 50 to 70 hours, but it will
not be cool enough for drawing under 12 or 14 days.
Mr. Mushet found the loss of weight in coking to be
as follows :—
Qfi'lll Yield of coke. Loss.
of free coals . . . . . 700 lbs. 1,540 lbs.
of splint and free coal mixed . 840 ,, 1,4100 ,,
of splint slightly mixed 1,000 ,, 1,2410 ,,
of pure splint . .. . . . 1,100 ,, 1,1420 ,,
It is calculated that in Staffordshire from 3;, to a
tons of coal, including that employed for roasting the
ore, are required for the production of 1 ton of cast
iron. In Wales, where the coal produces a larger
per-centage of coke, 3 tons of coal sufhce for the
manufacture of 1 ton of iron.
Sncrrou V.——Tnnonr AND Pnxc'rrcn or Incu-
srrnnrrne.
It has been already stated that oxide of iron is
easily reduced, if a stream of hydrogen be passed over
it at a red heat. A stream of carbonic oxide would
be equally eflicacious. But the reduction of these
oxides, however easy in theory, is difficult in practice,
because the particles of iron, as they are reduced,
become so intimately mixed with the gangue, that
they cannot combine or weld together. If the gangue
were fusible at a moderate heat, it would be sufficient
to raise the ore to the temperature at which the
stony matters fuse, and then subject the metallic
sponge thus formed to the blows of a heavy hammer,
or to the compressing force of powerful rollers. The
particles of iron would coalesce, and the gangue be
squeezed out in the form of scoriae or slag. If, how-
ever, the gangue were refractory, it would only fuse at
the temperature at which the iron in contact with the
fuel became converted into east‘ instead of rnalleahle
iron, which would otherwise be obtained. The ordinary
gangue of iron is clay or quartz, two substances
infusible by the heat of a blast furnace. In order to
determine their fusion, two methods are adopted. If
the ore be very rich, and it be required to produce
malleable iron from it by a direct method, the ore is
heated in contact with carbon: the gangue combines
with a portion of the oxide of iron, forming a very
fusible double silicate of alumina, and protoxide of
iron; while the other portion of the iron is reduced,
and all that is necessary is to pass the spongy mass

under a hammer to expel the slag, and bring about
the aggregation of the particles. But in this opera-
tion a portion of the oxide of iron is lost, varying in
amount with that of the gangue. This Calalan
process, as it is called, produces an excellent iron,
well adapted to the making of steel; it is still adopted
in some places where wood is abundant for making
charcoal, as in the Pyrenees, in Corsica, and some
parts of Spain; but unless the ore be avery rich one,
this process, wasteful alike of fuel and of ore, cannot
be adopted. In the poorer ores, where the object is
to extract as much of the iron as possible, the silicate
of alumina must be rendered fusible by giving it some
other base than oxide of iron, and for this purpose
the most economical is lime.
silicate of alumina and lime is much less fusible than
the silicate of alumina and iron, a very elevated tem-
perature must be employed; the iron combines with
carbon, and forms crude or cast iron, which is found
in a state of fusion below the fused silicate or slag.
By this method, which is essentially the English one,
nearly all the iron at present manufactured is pro-
duced. The iron ore, with a proper proportion of
carbonate of lime as the flux, and coke or coal as the
fuel, is raised to a very high temperature in an appa-
ratus called a blast furnace, a section of which is
represented in Fig. 1220, while Fig. 1227, will convey
a very good idea of its external appearance.
The blast furnace consists of two truncated cones
A, B, united at their bases. The upper part, called the
cone or hotly, is formed by an interior lining or shirl of
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.Fig. 1220. sxcrrox on BLAST FURNACE.
fire-bricks i i .' ll is another lining of fire-bricks, the
space between the two being filled up with broken
But since the double '
78 IRON.
and flux.
scoriae or refractory sand. The outer casing of fire
bricks tl, is supported by a thick wall of masonry or
brick, and this is strongly bound on the outside by
stout iron band's connected by long vertical bars,
whereby great strength and solidity is given to the
building. The exterior casing is also traversed by
numerous small channels, to allow ‘of the escape of
moisture from the masonry or brick-work, since any
pent—up steam might lead to the destruction of the
furnace. At the top of the furnace is an opening e,
called. the tfir'oat or tzmneZ-lzote, and above this is the
chimney r, in which are openings, which, with the
throat, are used for pouring in the charge of fuel, ore
The lower cone B, called the toe/res, is
formed of fire-brick or fire-stone, and requires the
greatest care in its construction, for upon its durability
depends the continued operation of the furnace. To
prevent the formation of an acute angle at the junc-
tion of the two cones, forming the body of the boshes,
the edges are slightly rounded off by the introduction
of a narrow belt, whereby a space is formed called
the telly. The lowest division n, called the lwrm‘t, is
nearly quadrangular in form: it is constructed with
large slabs of refractory sandstone cemented with fire-
clay. It is somewhat smaller at the bottom than at
the point where it meets the boshes, and its; angles
are gradually rounded off. The bottom of the furnace
is formed of a large fire-stone, supported by a mass of
masonry in which are various channels H, left open
for the escape of moisture from the brickwork; and
to keep the whole structure dry; the foundations are
traversed by two large arched. vaults v, v, which
intersect each other just belowthe axis of the furnace.
Three of the sides of the hearth are continued down
to the large fire-stone: the fourth side, D, is carried
down to a certain distance, where it is supported by
strong cast-iron bearers let into the masonryeof the
walls, which also support a heavy block of sandstone
called the tymp. Below this, at, a distance of 5 or 6
inches and a little in advance of it, is the dam-stone, (Z,






.' \
l \
~ xh
Fig. 1221. HoaIzoN'rAr. snc'rrou, SHOWING THE Tursnns.
of . cast iron called the ram-plate. The part * of the
furnace below the tymp iszcalled the cmcz'tte ; and in
it is collected the fused7 metal reduced by the opera-
\\


tions of the furnace. The three continuous faces of
the hearth are perforated a little above the level of
the tymp with holes 0 0, for receiving the nozzles of
tuyeres, which convey the blast from the blowing
machine to the furnace. The vaulted galleries LL
(corresponding to K K in Fig. 1221), allow the work-
men to pass from one t-uyere to another without loss
of time. -
Fig. 1221, is a horizontal section of the furnace at
the height of the tuyeres t, showing also their arrange-
ment and that of the pipes G which connect them with
the blowing-machine. Each pipe is furnished with a
valve worked by a screw on the outside, by which
the quantity of air admitted into the furnace is regu-
lated. The tuyeres, which are built into the hearth,
are conical tubes of cast-iron, and to prevent them
from being melted by the intense heat of the furnace
they are made hollow, and a current of cold water
allowed to circulate through them in the direction of
the arrows‘, Fig.
1222, one pipe
bringing the ‘ » A
cold water and the other dis-
charging it af-
ter it has been _
heated. Within these tuyeres are placed the nozzles
of the blast pipes; and it will be seen by reference
to Fig. 1221, that by setting the. tuyeres not opposite
each other but somewhat inclined, the blasts do not
meet each other, but each one operates upon a different
part of the hearth H.
_ The blowing-machine in common use is shown
in section in
Fig. 1223. It
consists of a
large cylinder of cast-iron A, a W
furnished with
a piston‘ 1?,
fitting air-
tight, the pis-
ton rod R pass-
ing through a.
stuffing-box at
the top, and
usually con- /
nected by a
parallel adj ust-
ment to the oscillating beam of a'steam engine. The
cylinder is closed at the two extremities, but there
are two lateral openings 0 v’” cémmunicating with the
outer air, and two other" openings 0’ '1)" communicating
with a side chamber B,_also of east-iron. The opera-
tion of this machine is as follows :—-Supposing the
piston to be descending from the top to the bottom
of the cylinder, itwill condense the air below it; this
will forcev open the valve 7;’ and escape into the


Fig. 1222.

Fig. 1223'. warren or BLOWING MACHINE.
' chamber 13. By- this act the valve 22'” will be more
firmly closed, since-it is so hung that it can only open
from without’ inwards. While this operation is pro-
ceeding,_p_the above the piston being greatly rarefied,
. IRON.
79
the denser air on the outside forces open the valve 5,
and rushes in 5 the valve 22'' cannot open during this
act, because it is hung so as to open only from A into
28, not from 13 into A. Supposing the piston to have
arrived at the bottom of the cylinder and to be
ascending, the air above it becomes condensed and
passes through 12'’, into B, while v becomes firmly
closed; at the same time fresh. air rushes in below
the piston through c’”, and '0' is closed. From B, the
air passes through 0, to the pipes G G, Fig. 1221, and
the use of the chamber 18 is, to ‘allow the air to
equalize itself so that it may proceed through 0 in a
stream of tolerably equal density. It is not unusual
for each blowing machine to be provided with two
cylinders, which act alternately ateach stroke made
by the beam of the steam engine by which it is worked.
Some of the large Welsh furnaces 1 consume on an
average 3,600 cubic feet of air per minute, or about
nine tons wezjy/z't of’ air per hour. The pressure at
which the air is sent into the hearth varies with the
nature of the fuel and the season of the year. When
the air is rarefied by the heat of summer, the blowing
machine must be exerted more than

The centre port K passes downwards to an ex-
ternal opening for the admission of the air, and the
discharge ports L L, deliver into the passages M, on
the top of the cylinder, which communicate with the
air main N, by the chest 0, formed between the cy-
linders. The piston of the blowing engine is made
without any packing, it being a light hollow cast-iron
piston turned to an easy fit. The slide valve of the
blowing cylinder has a packing plate at the back,
working against the cover of the valve box, with a
ring of india-rubber inserted between this plate and
the back of the valve, to give a little elasticity.
Such an engine is capable of supplying air to a blast
furnace which makes 160 tons of iron per week, with
a surplus blast for a cupola or refinery. Such an
engine, with the piston moving with a speed of 610.
feet per minute, is capable of supplying nearly 30
circular inches of tuyere at a pressure of 3-g-lbs. to the
square inch.2
The dimensions of the blast-furnace vary with the
kind of ore to be smelted. Some are only 36 feet
high including the chimney; others are about double
M
F_'_'I
in winter, in order to supply the fur- All
naee with the same amount of oxy— J
gen. Less pressure is required with N l
a light and easily combustible fuel, 1"



such as charcoal, than with a dense
coke. In the former case the pres-
sure may not exceed élb. on the
square. inch; in the latter, the ave-
rage is about 2-5— or 3 lbs.
The objection to this form of
blowing-engine is its great size, and





the small velocity with which the air 3‘, 4.“?
is driven, this being no higher than I
that of water passing through an
ordinary pump. When the engine is
not driven by Water power, but by
steam, there is no reason why as
,\~
great a velocity should not be im-
parted to it, as a high-pressure
locomotive power is capable of sup-
plying. With these views Mr. Archibald Slate of
Dudley has contrived a blowing engine, the construc-
tion of which will be understood by referring to
Figs. 1221, 1225, which represent an elevation and
plan thereof. A A, are the steam cylinders, each 10
inches in diameter and with 2 feet stroke, and ER the
blowing cylinders, 30 inches in diameter and 2 feet
stroke, with their pistons C fixed on the same piston
rods D, which are connected to two cranks E, fixed at
right angles to each other on the same shaft. The
slide valves F of the steam cylinders are worked
by the eccentrics G, on the cranked shaft, and the
cranks H, at the outer ends of the same shaft,
work the slide valves I of the blowing cylinders.

(1) The diinensions of the great blowing cylinder at one of the
largest of the Welsh iron works are as follows :—-diameter 9 feet 4
inches, height 8 feet 4- inches. The piston has a range of 8 feet,
and makes 13 strokes in a minute. Allowing 4 per cent. for loss
by leakage, we have 12,588 cubic feet of air expelled per minute.

Fig.9. 1224, 1225. EnEvATIoN AND PLAN or' sLA'rE’s HIGH rnEssUaE BLOWING
ENGINE.
that height; but the usual height is from 15 to ‘50
feet without the chimney, which is 8 or 10 feet more.
In such a furnace the crucible will be about 6% feet
high, and 2% feet square at the topythe boshes 8

(2) The speed of a locomotive piston at 10 miles per hour is
about 800 feet per minute. In 1850, Mr. Slateerected at the
Woodside Iron Works, near Dudley, a 40-inch blowing cylinder,
worked by a steam engine with a cylinder 11 inches in diameter.
The stroke was 2 feet, the boiler 27 feet long and 1 feet diameter.
On the outlet pipe were placed 4 tuyeres, 2 of them 2l inches, the
others 2 inches diameter. The engine being run up to its full
velocity, reached 145 strokes per minute, at which rate the density
‘of the air issuing from the 1 tuyeres was nearly 5lbs. per inch;
but the engine was perfectly noiseless and steady on account of
the great regularity of the blast. With an adjusting expansive
valve fitted to this apparatus, its full complement of blast was
thrown into one furnace, viz. 3,500 cubic feet of air per minute:
the pressure of the air in the main close upon the engine was a
little over 3lbs. to the inch; at the tuyeres on the furnace it was
1' athel' under; the loss being due to friction and leakage on account
of the tortuous character and length of the main, which exceeded
300 feet.
80
IRON .
feet high, and 12 feet in diameter at the top; the
cavity of the furnace is about 30 feet high; . the
chimney 8 feet high, and widened to 1.6 feet to allow
the charge to be easily tossed in. The form of
furnace shown in Fig.1220 is adapted to the hot-blast;
cold—blast furnaces being narrower at the top. Some
of the largest-furnaces are in South Wales, in which
the diameter at the boshes, or widest part, is from 15
to 18 feet. These have a capacity of 7,000 cubic
feet, and contain at least 150 tons of ignited
materials. '
Much care ‘ is required in raising a new furnace to
the temperature. necessary for the smelting of iron.
A temporary fire-place is first erected ‘at the lower
part, to which the whole cavity of the furnace is
,made to act as a chimney, so that whenv the fire is
lighted, the draught is violent, and much heat is
carried up. The fire is kept burning for about three
weeks, at the end of which time the furnace is sulfi-
cien-tly dry to receive a charge of coke. The tem-
porary fire-place is then removed, and other prepara-
tions are made for the purpose. A quantity of ignited
coke is thrown in, and this is gradually increased
until the whole cavity is filled. The quantity required
by a furnace of the average size is about 99,000 lbs,
the splint coal for which would weigh 198,000 lbs.
When the furnace has been sufhciently heated by
coke, proportionate charges of coke, ironstone, and
blast-furnace cinders are added. At first the iron-
stone bears only a small proportion to the weight of
the coke, but is afterwards increased to the full
burden. The filling is continued regularly, and when
the top of the furnace has acquired a considerable
degree of heat, the blast is introduced. Before
admitting the blast, the dam-stone and dam-plate are
laid. On the top of the plate is a slight depression,
curved outwards, to allow the. slag to flow off in a
connected stream, as it tends to surmount the level
of the dam. From the dam-plate to the level of the
floor, a declivity of brick-work is erected, down which
the slag flows. The fauld is stopped up with sand,
and the furnace bottom covered with powdered lime
or charcoal dust. Ignited coke is then allewed to
fall down, and is brought forward with iron ‘bar's
nearly to a level with the dam. The tuyere holes
are opened, and lined with a soft mixture of fine
clay and loam. The blast is first introduced through
a small discharge-pipe, and afterwards a larger one is‘
used... In about 2 hours after blowing, a considerable
quantity of lava will be accumulated; this is admitted
to all parts of the hearth, and glazes the surfaces of
the fire-stone. It then rises to a level with the notch
in the dam-plate, and flows over. When the metal
has risen nearly to a level with the dam, it is let out
by cutting away the hardened loam of the fauld, and
conveyed by a channel made in the sand in front of
the furnace, to the place where it is cast into pigs,
as will be noticed more particularly hereafter. In 6
days from the commencement of blowing, the furnace
‘will have wrought itself clear, at which time the
chargewillbe in the following proportions :——4=00 lbs.
of coke, 336 lbs. of clay ironstone, and 100 lbs. of

limestone. This charge is thrown into the furnace
every hour. In the hilly district of Colebrook Dale,
the blast-furnaces are built by the side of a hill, on
the summit of which the charge is prepared, and tossed
V
.a
n
él’lglillgtyll
i _-
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we‘ 3' ' N},
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lid. ‘ -- " m" l‘lillPfld“
‘ ' ' ' r 1 .-
1 ~' . i, ,2





T:
l .'
1,5,: l‘? " ‘ _ a.
if.’ ‘"11"’ l ’ I I
Fiq. 1226. MOUTHS or BLAST—FURNACES. (Colebrook Dale.)
into the furnace mouth, as shown in Fig. 1226. Near
Dudley the charge is in some cases moved by steam
power up an inclined plane, as represented in Fig.
1227; in other cases a mechanical lift is employed.
The action of these three substances upon each
other, leading‘ to the production of a vitreous slag,
and metallic iron, has already been stated. The
lllLll , tie.
mlllltlfllliily i ‘if -_ llllhh' rltlllllllhnr ' hhmtihtg n’;-
" mini‘, 1, l "-1
“ht; ' "
- lllllllllllleifit
"“ s. ‘-.-' '. H i '-
r W 1‘“ 4*" "iii-YEW“ , ‘.4:-
_(.V V Rw'tryg‘. ‘a ‘up -
g ’ ‘i if“
Fig. 1227. BLAST-FURNACES NEAR DUDLEY. ,
chemical changes by which these apparently simple
results are brought about, are somewhat complicated.
The charge having been thrown in at the top of the
furnace, gradually descends until it reaches the
upper part of the boshes. In the cone the heat is
not very great: near the-boshes it is considerable,
and in the hearth it is at its maximum, for here the
oxygen of the blast meets the fuel, and produces the




IRON.
81
most vivid combustion. At about the middle of-the
boshes, the heat is much diminished, for the oxygen
having been converted into carbonic acid, this gas
and the nitrogen of the air of the blast part with a
portion of their heat to the fuel and the mineral at
the lowerpart of ‘the cone. Here the carbonic acid,
in contact, with the heated fuel, combines with an
equivalent of carbon” and becomes converted into
carbonic oxide, with, a great expansion of volume, and
consequently a great absorption of heat, so that
while the boshes are at awhiteheat, the base of the
cone is only at a red. As the carbonic oxide, at a
high temperature, comes in contact with the oxide of
iron, it reduces it to a, metallic state, and becomes
converted into carbonic acid. This acid gas is also
formed by the conversion of the limestone into caustic
lime, so that the gases which escape by the throat of
the furnace consist of nitrogen, carbonic oxide, and
carbonic acid. There is also a portion of hydrogen and
earburetted hydrogen, arising from the dry distillation
of the fuel in the upper part of the cone, for the
coal is never so thoroughly'coked as to have parted
with all its gases. A certain amount of moisture
enters by the tuyeres,'and its decomposition increases
the quantity of carbonic oxide and hydrogen. Hence
it will be seen that a vast amount of inflammable
gaseous matter must be constantly pouring from the
blast-furnace all the time that ‘it is in action, produc-
ing a great body of flame and smoke by night, and
lighting up the country for miles around.
The chemical changes which go on in different
parts of the furnace, have been tested by collecting
the gases at various distances below the throat or
tunnel-hole, by passing a wrought-iron pipe to the
depth at which it was required to examine the pro
ducts of combustion. To the upper extremity of
this tube was connected a leaden pipe, by which the
gases were conducted to a place suited for their ana-
lysis. Near the throat of the furnace, the hygro-
scopic water is driven off from the charge. When it
has sunk to the distance of 10 or 12 feet from the
surface, the combined water of the hydrated oxide of
iron begins to be expelled, and a little lower down,
the carbonic acid, both of the ore and of the flux, is
partly set free, and a portion of the oxide of iron
becomesreduced to the metallic ‘state. In the lower
part of the cone, and at the commencement" of the
boshes, the reduction is completed, and the rest of -
the carbonic acid liberated. At the lower part of the
boshes, where the temperature is very high, the lime
of the flux and the ash of the fuel combine with
the silica to form various double silicates, which
afterwards form a fusible slag. Here also the iron is
exposed in a slightly oxidising atmosphere to a very
high temperature in the presence of carbon, a portion
of which substance combining with the metal,
converts it into east-iron. The presence of the iron
and the carbon also serves to reduce a portion of the
silica, the silicium combines with the iron, and the
oxygen of the silica with the carbon. When the
charge thus modified arrives at the upper part of the
hearth, the intense heat, caused by the action of
von. II.
the blast upon what remains of the fuel, completely
fuses both the iron and the silicates, and they pour'
down into the crucible beneath. The construction
of the hearth allows the melted products to fall
rapidly through the blast, and this is quite necessary,
for the oxidising influence of the vast body of air
poured into this part of the furnace is such, that it
would speedily convert the reduced metal'to an oxide,
which would be rapidly absorbed by the slag, and
thus occasion great loss. But on reaching the
crucible, the fused products arrange themselves in
the order of their density. The iron occupying the
lowest part, and being covered by “the silicates, is
completely protected from all oxidising influence.
The silicates or slag occupy a volume five or six times
greater than that of the iron, so that as it rises to:
the level of the dam-plate, it flows over, and passes
down the inclined plane to the ground, and when
cold is removed by means of pointed iron levers.
At some works the slag is made to flow into iron
waggons, whereby it is moulded into large blocks.‘
These waggons run on a railway, so as to admit
of being easily wheeled off. The iron slowly accu-
mulates in the crucible, and in the course of 8, 12 or
more hours, according to the construction of the
furnace, the furnace is lappecl, and the liquid metal
drawn off. For this purpose the plug of refractory
clay, which closes a hole in the bottom of the crucible,-
is pierced with a long bar. But before tapping, the
men prepare for the reception of the liquid metal a
number of moulds in the sand which composes the
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‘.Fz'y. 1228. cxs'rrne PIG—IRON.
‘floor of the ‘workshop. For this purpose blocks of
wood are buried, which on being taken up leave a
number of parallel trenches. These are connected
by a channel at right angles to them, and commu-
nicate with the hole at the bottom of the crucible.
The blast is then shut ofi, the plug of clay removed,
and the molten stream flows out sparkling and bright,
the light and heat becoming more and more intense

‘as it rolls on and increases in volume. In order to
c
82 IRON.
make the metal flow regularly into the side channels, ‘
it is necessary here and there to interrupt the pro—
gress of the stream by a long piece of wood, as the
metal does not continue sufficiently fluid to fill them
up equally without this precaution. The moulds
form the metal into semi-cylindrical bars called pigs,
united by one of larger dimensions called a .9020, the
moulds being so arranged as to make the points of
connexion very thin between the pigs and the sow,
so that the" pigs are easily broken off when the cast-
ing is cold. iWhen the crucible is emptied, the clay
plug is restored, the blast is put on, and the opera-
tions of the furnace proceed as before, day and night,
weekday and holiday, for years together,‘- for it is
absolutely necessary to keep up the heat of the
furnace, and this can only be done by keeping it at
work; for should it once .cool down, this huge and
costly piece of apparatus would be ruined.
The quality of pig-iron produced in an ordinary
blast-furnace from clay iron-stone, and with coke as
the fuel, is subject to considerable irregularity; but
the experience of years has enabled the skilful iron
master to classify the irregularities, so to speak, into
marketable products. Six different kinds of pig-iron
are distinguished. The first three, named No. 1,
No. 2, and No. 3, are considered as foundry metal ,-
they contain carbon in different degrees, but all of
them in a‘ higher degree than those selected for
making'bar or malleable iron. No. 1 is saturated
with carbon, the effect of which is to produce a soft
iron, very, fluid when melted, so that it will adapt
itself perfectly to the shape of the mould, and is
hence used for small and ornamental castings. It is
also so soft as to yield readily to the chisel. No. 2
contains less carbon than No. 1: it is not so soft
when cold, __nor so fluid when melted; but being
harder and stronger, is preferred for those parts of
machinery which require strength and durability.
The quantity of carbon contained in these two sorts
renders them unfit for being manufactured into bars;
buti'No. 3, or dark-grey iron, containing less carbon
than No. 1 or No. 2, can be used either for the forge
.for the foundry. It is employed in heavy castings,
such as tram plates, heavy shafts, wheels, cylinders
of steam-engines, &c. The next quality is called trig/it
iron, from its being of a lighter colour and of a
brighter lustre than the foregoing varieties. It is
usedyf'or large castings, but is not sufiiciently fluid
for fine work. Afifth variety is mottled iron, the frac-
ture of which is mottled with grey and white. It is
too thick and brittle for the foundry, and its use is
confined to the forge. The last variety is called
zo/n'to iron, from'its silvery white colour. It is quite
unfitqgfor' casting. on account of its thickness and
extreme brittleness. It contains a smaller proportion

a -- ;- r " - r .
~gl) A well-constructed furnace will work four or five years
witlitiiit requiring vrepair, and then only the refractory lining will
halvéito' béieconstructedl' Some of the Welsh furnaces have been
wprked for more than ten years without requiring any extensive
repairs, and at the end of that time, only the loser portions
of the lining have required reconstruction; the upper Part of {he
c'oriebeing'exposed to only a moderate temperature, has been
known to last for nearly forty years..

of carbon than any other sort of pig iron ; indeed its
production often depends upon a deficiency of fuel in
the charge.
The difierent kinds of iron present different pheno-
mena in flowing out of the furnace. They have been
well described by Mr. Mushet. “When fine, (No. 1.)
or super-carbonated crude iron is run from the fur-
nace, the ‘stream of metal, as it issues from the
fauld, throws off an infinite number of brilliant
sparkles of carbon. ‘ The surface is covered with a
fluid pellicle of carburet of ‘iron, which, as it flows,
rears itself up in the most delicate folds. At first
the fluid metal appears like a dense ponderous stream,
but as the collateral moulds become filled, it exhibits
a general rapid motion from the surface of the pigs
to the centre of many points; millions of the finest
undulations move upon each mould, displaying the
greatest nicety and rapidity of movement, conjoined
with an uncommonly beautiful variegation of colour,
which language is inadequate justly to describe.
Such metal in quantity will remain fluid for twenty
minutes after it is run ‘from the furnace, and when
cold will have its surface covered 'with the beautiful
carburet of iron already mentioned, of an uncom~
monly rich and brilliant appearance.”
Very different are the phenomena presented by the
inferior iron, No. 4:. From all parts of the fluid
surface is thrown off a vast number of metallic
sparks, arising from a cause different to that exerted
in the former instance. The absence of carbon
renders the metal liable to the oxidising influence of
the atmospheric air. Small spherules of iron are
ejected from all parts of the surface, to the height of
2 or 3 feet, when they inflame, and separate with a
slight hissing explosion into a great many particles
of brilliant fire, forming oxide of iron. “ The sur-
face of oxygenated iron, when running, is covered
with waving flakes of an obscure smoky flame, accom-
panied with a hissing noise, forming a wonderful
contrast with the fine rich covering of plumbago in
the other state of the metal, occasionally parting, and
xhibiting the iron in a state of the greatest apparent
purity, agitated in numberless minute fibres from the
abundance of carbon united with the metal.” As
the oxygenated iron cools, its upper surface becomes
covered with a scale of blue oxide, which being
removed, a number ‘of deep pits are presented.
“ This iron in fusion stands less convex than carbon-
ated iron, merely because it is less susceptible of a
state of extreme division; and, indeed, it seems a
principle in all metallic fluids, that they are convex
in proportion to the quantity of carbon with which
they are saturated.” The appearance of No. 2 and
of No. 3 in' a state of" fusion, present some of the
phenomena both of No. l and'of No. 41.
The‘ quality of‘themetal 'can also be judged of
before it is run from the furnace, by the colour and‘
form of the‘ scoriae, the colour of the crust upon the
working bars, and the quantity of carburet attached
to it. That cinder which indicates the presence of
carbonated'iron in the hearth of the furnace, forms
itself into circular compact streams, which become
‘in
IRON-i
'83
consolidated and inserted into each other: these are
from 3 to 9 feet in length. “Their colour, when the
iron approaches the first quality, is a beautiful variega-
tion of white and blue enamel, forming a wild profu-
sion of the elements of every known figure. The
blues are lighter or darker, according to the quantity
of the metal, and the action of the external air while
cooling. When the quality of the pig-iron is spar-
ingly carbonated, the blue colour is less vivid, less
delicate, and the external surface rougher and more
sullied with a mixture of colour.” The furnace-cinder
when No. 3 iron is produced, assumes a long zigzag
form. “Its tenacity is so great, that if whilefluid a
small iron hook be inserted into it at a certain degree
of heat, and then drawn from it with a quick but steady
motion, 20 or 30 yards of fine glass thread may be
formed with ease. When by accident a quantity of
this lava runs back upon the discharging-pipe, it is
upon the return of the blast impelled with such
velocity as to be blown into minute delicate fibres,
smaller than the most ductile wire. At first they
float upon the air like wool, and when at rest very
much resemble that substance.” The cinder fre-
quently crystallizes in cooling: cellular masses form
among it, which on being opened, are sometimes found
full-of perfectly crystallized forms.
THE HOT-BLAST.—Tl16 enormous quantity of air
injected into a blast-furnace to promote the combus-
tion of the fuel, must have its own temperature
raised before its oxygen can combine with the carbon
of the fuel in the way of combustion. In fact one
portion of the heat of the furnace is expended in
raising the air to the temperature necessary for the
combustion of the remaining fuel: a second portion
of the heat is carried off by the nitrogen of the
injected air, and by the volatilized products; while a
third portion is employed by the ore and the flux 5 so
that not only is there a wasteful expenditure of heat,
but the very means employed to raise the temperature
of the furnace, has the effect of keeping down the
temperature. If, however, the temperature of the
air be raised to about 600° before it is injected into
the furnace, a much higher temperature can be
obtained with the same charge of fuel, or the same
temperature with a diminished charge of fuel. It
has been calculated that by the use of the blast at
57 2° instead of 60°, a furnace may have its tempera-
ture raised one-eighth; and supposing the temperature
obtained by working with cold air to average 2,7 00°,
the hot-blast will raise it to 3,060°, making a difier-
ence of 360° in the effective heat of the furnace.
Hence many substances infusible in a cold—blast
furnace, become fusible in a hot. Coal can be used
in the hot-blast furnace instead of, or mixed with
coke; less fuel and less limestone flux are required;
and ores previously unfitted for the manufacture of
foundry iron can be smelted.
Figs. 1229, 1230, are vertical and lateral sections of
the apparatus for heating the air which supplies the
blast. It consists of a kind of stove, in which the air is
made to pass through a series of cast-iron pipes before
arriving at the nozzles by which it is injected into
a?“
the furnace; AA is the Wall of the furnace, B a
section of one of the Syphon-shaped tubes, arranged
asinFig. 1230, from 6 to 3 inches in diameter. These
are connected by sockets and iron joints to horizontal
pipes A of‘ much greater diameter. E is the fire-
place for heating the pipes, which are surrounded by


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Figs. 1229, 1230. SECTIONS OF
DOT—BLAST APPARATUS.
.. ..-..-..-.-...-.
a large hot-air chamber,
into which the gases from
the fire—place escape by the
openings D 1) at the crown
of the arched covering r. The draught is regu-
lated by a damper placed over the top by which the.
openings can be more or less closed by moving a.
compound lever. The large cylinder J, Fig. 1230,
communicates with the cylinder by which the blast
is supplied, and is large enough to neutralize the
vibrations occasioned by the oscillation of the piston
by which air is forced into the furnace. The hori-
zontal connecting-pipe A, through which the cold
air enters the stove, is furnished with a stop or
diaphragm in the middle, and the air, in order to
escape by the pipe on the opposite side, must traverse
the syphon-pipes B, the heat of which raises the
temperature of the blast to the proper point. In
most cases each tuyere is provided with a heating
apparatus; and in a furnace producing 60 tons of
cast-iron per week, from 30 to 35 tons of coal will be
required in that time _for raising the blast to the
temperature of 600°.
It has been proposed to employ the highly-
heated .gases which escape from the throat of the
furnace, for the purpose of heating the blast with
which it is supplied. When it is considered that one
of the large Scotch furnaces yields from 150 to 206
tons of iron per week, with a consumption of from
300 to 400 tonspf coal, and that from 41,000 to
5,000 cubic feet of air per minute is injected into it,
we may form some idea of the enormous waste of
heat in the volumes of smoke and flame which are
being constantly discharged from its chimney. Many
methods of applying this waste heat to the heating
of the blast have been proposed, but most of them
have been objectionable on account of the difficulty
of repairing the apparatus without blowing out the
e 2
8a
IRON.
furnace. The least objectionable method is that by
Mr. Budd, as employed at the Ystalyfera iron works
in South Wales. The heating ovens are arranged so
as to be quite distinct from the furnace, so that they
can be repaired without interfering therewith. The
stoves are built in the masonry a littlelbelow the
throat of the furnace, and a chimney, 25 feet higher
than the top of the platform, afiords the means of
drawing into them as much of the hot air and flame
as may be required. This arrangement will be under-
stood from Fig. 1231, in which a is the furnace, b a
series of fines situated about 3 feet from‘ the top for
conveying the hot air into the chamber a, Fig. 1232, in
which are placed the arched pipes (Z, heated by the
gases from the furnace. The heat of the stove is regu-
lated by the chimney e and its damper j: The cross-






,. r. .
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Fig. 1231. ‘ Fig. 1232.
pipes 9 connect together the upright air-tubes (Z, and
the side pipes 72, convey the blast which arrives by
the upcast mains z', to the various cross-pipes. The
heated air ‘is afterwards conveyed to the tuyeres by
the downcast pipes j Z. There is also a door lr'in the
the brick-work to allow the apparatus to cool before
going in to make repairs. The gases which escape
from the furnace have a temperature of about 1,800",
so that it‘ is only necessary to draw through the
chamber such a supply (about one-sixth of the whole
quantity has been found sufficient) as will heat the
stream of air in the tubes to 600°. To do. this the
gases should leave the stove at 800°. If the tem-
perature of the hot-air chamber decline, it may be
raised by slightly elevating the damper jI At the
Tstalyfera works, another portion of the waste gases
is conducted through flues, and made to heat the
boilers which supply the engine of the blowing
machine, and there is still a large amount of heated
air and flame which passes off without doing any
‘service. The economy of fuel by these arrangements
is about one-third, so that 2 tons of coal produce
the same quantity of iron as was formerly produced
by 3 tons. I
From the results of some experiments by Messrs.
Bunsen and Playfair, upon a hot-blast furnace near
Alfreton, in Derbyshire, it was concluded that 8154:
per cent of the heat generated by the furnace is con-
tinually carried off by the unconsumed gases escaping
from i the chimney. This estimate appears to be
‘excessiva'but there is no doubt that the amount of
heat thus wasted is very large. In Great Britain,

where theabundance of fuel leads to its extravagant
expenditure, little more has been done to apply this
vast body-of heat to useful purposes, than to heat the
blast ‘or the boilers of the steam-engine, as already
stated. On the Continent, however, some successful
attempts have been made to apply this heat not only
to the above purposes, but also to the roasting of the
ores, and to the refining and puddling of iron. For
this purpose the gases are‘ drawn off from the furnace,
cooled and purified by being passed through water,
and when ignited, they burn with a very intense heat.
In some cases air-pumps are employed to propel the
gases to the places where they are to be used as
fuel.
The chemical changes which take place in a hot-_
blast furnace were examined by Messrs. Bunsen and
Playfair, in 1845, in the furnace already indicated.
This furnace is 40 feet high, 11 feet wide at the
boshes, and is blown with air heated to 626°, under a
pressure of 6.7 5 inches of mercury, the diameter of
the nozzles being 2?,- inches. The furnace is supplied
in the course of 241 hours with 80 charges, each con-
sisting of 420 lbs. of calcined ore (clay carbonate of
iron), 390 lbs. of coal, and 170 lbs. of limestone.
The coal and ore are charged in large lumps: the
limestone in lumps about the size of the fist. The
product of each charge is stated to be 1110 lbs. of
pig-iron. _ _
In order to collect the evolved gases, a wrought-
iron tube was passed into the furnace to the,
various depths at which it was desired to examine
the products of combustion; and to the upper
extremity of this tube was attached a leaden pipe,
by which the gases were conducted into proper
vessels for analysis. At a certain depth the heat of
the furnace was so great that the iron tube became
fused. A small hole was therefore bored through the
masonry from the front of the furnace to its internal
cavity, so as to reach the hearth just beneath the
boshes, at a distance of six feet from the bottom of
the crucible, and two feet nine inches above the
tuyeres. The gas drawn off from this opening ex-
haled a powerful odour of cyanogen; and in kindling
it, the flame exhibited the purple tint characteristic
of that substance. Analysis showed ‘an amount of
cyanogen equal to 1'34 per cent. The other results,
as obtained at various depths from the top of the
furnace, are exhibited in the following table, which
will also show the various changes produced by the
current of air during its passage from the tuyeres to
the chimney :—



Depth from the top.
I. II III. IV. V. VI. VII. VIII.
8 ft. 11 ft. 14 ft. 17 ft. 20 ft. 23 ft. 24 ft. 34 ft
Nitrogen . . . 54-77 52-57 50-95 55-49 60% 58-28 5675 5805
Carbonic acid . 9'42 9'41 9'1012'43 1083 8191008 000
Carbonic oxide 20'97 2924 19-36 19-77 1977 29-97 2907 25-19
Light Carbu- '
retted Hy— 8'23 4'57 6'64 4-31 4-40 1*64 2-33 0'00
drogen . . .
Hydrogen. . . 6'49 9'3312'42 7'62 4'83 4'92 5'65 3'18
Olefiant Gas. . 0'85, 0'95 1'57 1'38 0'00 0'00 0'00 0'00
Cyanogen . . . 0'00 0'00 000 0-00 0-00 trace trace 1'34.


IRON. '85
It will be seen, from the production of 'carburetted
hydrogen, that the coking of the coal goes on even
to the. depth. of twenty-four feet. At a depth of four-
teen feet, the amount of nitrogen is least; while at
the same depth the amount of hydrogen and car-
buretted hydrogen is greatest: this, therefore, ap-
pears to be the zone of the most active distillation.
It was found by analysis that 100 parts of the fur-
nace-coal yielded a mean of ‘769 sal ammoniac ; and
as 280 cwt. of coal were consumed in twenty-four
hours, it follows that 2 cwt. of sal ammoniac might
be obtained from it, as a secondary product, simply
by conducting the gas, previous to its application as
fuel, through a chamber .containing. muriatic acid.
The quantities of carbonic .oxide and carbonic acid
have no proportional relation to each other; but it
would appear, from the constant results obtained at
the depth of twenty-four feet, that below this point
there is a continuous liberation of carbonic acid, ob-
tained either from the limestone flux, or caused by
the reduction of the oxide of iron, or probably from
both sources. Judging, however, from the average
vcomposition of the gases evolved from the materials
employed, the excess of carbonic acid may be due to
the flux, the reduction ofthe-_,__ore taking place at the
boshes only. But “the most ir‘nportant feature of this
investigation is the discovery of the presence of large
quantities of cyanide of potassium in the lower region
of the furnace. On introducing an iron pipe into the
hole pierced in the front of the masonry above the
tuyeres, large quantities of this vsubstance were readily
collected. To do this, the iron tubing, in order to
prevent its being fused, was inserted to within a
certain distance only of the internal cavity of the
furnace; and to its outer end was attached a series
of receivers, in which the various products were
cooled and collected. From the quantities thus ob-
tained from a given volume of gas, it was calculated
that at least 224 lbs. of cyanide of potassium were
daily generated in the furnace. When the iron tube
used in this experiment was withdrawn from the hele,
it was found to be internally encrusted with melted
cyanide of potassium, which became deliquescent on
exposure to the air.” The sources of the potash
were the calcined ore, which contained 0'7 418 of
potash, and the coal, which contained 0'07 per
cent. It had been shown by Mr. Fownes, “that
cyanide of potassium is produced on passing a
current of nitrogen gas over a mixture of charcoal
and carbonate of potash, strongly heated in an
iron tube; “and it consequently appears that the
cyanogen present is furnished solely by‘ the direct
union of the liberated nitrogen with a portion of the
carbon constituting the fuel. Since, also, potash is
reduced at a high temperature in the presence of
carbon, it follows that no formation of cyanide of
potassium in the region immediately above the tuyeres
is due to the direct union of carbon with potassium,
and the nitrogen of the air. The presence of this
substance in the hearth of the furnace cannot fail to
eflect extensive chemical changes, and influence, to a
considerable extent, the reducing power of the appa-

ratus. It has been shown that, at very elevated
temperatures, this salt is volatile; and if, therefore,
it reaches the part of the furnace in which the reduc~
tion of the ore is efliected, its high reducing proper-
ties will necessarily come into play. By this means
it must become decomposed into nitrogen, carbonic
acid, and carbonate of potash, of which the two
former will pass off in the form of gas, while the‘
latter, not being volatile, is carried down by the
other materials in the furnace, until it reaches the
point at which it is again transformed into cyanide of
potassium. In this way we can easily understand
that the accumulation of cyanide of potassium may
ultimately become very considerable, and capable of
materially influencing the action of the apparatus.
When the proportion of this salt has become in-
creased beyond a certain amount, the excess is pro-
bably decomposed, by the action of the blast, into
nitrogen and carbonic acid, which escape. in the
gaseous form, and into carbonate of potash, the
potash of which unites with the siliceous matters
present, and is carried oif by the slag. It is evi-
dently very diflicult to determine the exact nature of
the various chemical actions continually taking place
in the different parts of an apparatus of such im-
mense size and so highly heated as a blast furnace;
but it is certain that the presence of large quantities
of a material of a character so highly reducing as
cyanide of potassium cannot fail to materially influ—
ence the chemical changes which are there effected.
The amount of this substance is probably greater in
hot blast furnaces than in those at which air at the
ordinary temperature is employed 5 but the quantity
generated even in the cold-blast furnace must to a
certain degree modify the reactions before described,
and contribute to the reduction of ,the ores.”1
SEorIon VL—Tnn MANUFACTURE or Wnouen'r
Inon.
The cast, or pig-iron, produced by the operations
have thus far described, is contaminated
with impurities, which render it brittle, and incapable
of being wrought into shape by the hammer. The
impurities consist chiefly of carbon and silicium,
together with small. portions of sulphur and phos-
phorus. The carbon and silicium are got rid of ‘by
exposing the pig-iron for a considerable time to
oxidizing influences, such as heat and a' blast of air.
The effect of this is to convert the iron into oxide of
iron, which forms first on the surface, and gradually
penetrates into the mass. The carbon of the iron
reduces the oxide first formed, producing metallic
iron and carbonic. oxide gas. By a similar reaction,
the silicium of the iron is converted into silicic acid,
which, combining with a portion of the oxide of iron,
forms a fusible silicate of iron. These actions and
reactions are continued, until at length the whole

(1) Phillips’s Manual of Metallurgy. The Report of the expe-
riments by Messrs. Bunsen and Playfair was made to the British
Association for the Advancement of Science in the year 1845', and
is published in the 15th volume of the Reports. It is entitled
“Report on the Gases evolved from Iron Furnaces, with referee (58
to the Theory of the smelting of Iron.”
as
TRON.
mass is converted‘ into a spongy mass ‘of malleable‘
iron and fusible ‘slag. This ‘is subjected to the per—
cussion of a heavy hammer, or to great pressure,
whereby the silicates are pressed out. The whole
of the silica of the slag is not due'to the silicium of
the iron; a considerable portion of it comes from the
sand which adheres to the pigs in the casting;
‘ another portion may also be ‘derived from the coke
used in the refining- furnace.
The cast-iron pigs‘ also contain small portions of
sulphur ‘and phosphorus, which must be carefully
removed during the refining, as their presence would
effectually destroy the valuable properties of wrought
iron. The separation of these substances is, how-
ever, a matter of great diificulty, so that it is better
to get rid of them previous to smelting, by a careful
roasting of the ore; but if the source of sulphur be
‘the iron pyrites of the fuel, a large dose of carbonate
of lime must be added to form sulphuret of calcium,
which then escapes with the slags. The phosphorus
may be removed by similar means 5 but ores contain-
ing much phosphorus ‘or sulphur can never be made
to furnish good iron. _
A furnace which supplies iron‘for the refinery is
worked so as to produce that variety of cast-iron
called white-iron, on account of its containing a very
small proportion of carbon. For this purpose the
charge of ore is large in proportion to that of the
fuel ; and the blast is urged at high pressure in order
to determine the rapid descent of the ore. The ore
ought to be of good quality.
The English method of refining pig-iron consists of
two consecutive operations carried on in separate
furnaces. In the first, which is called the jim'rzy-
fumaee, or the refinery, the metal is melted, and, after
being exposed to the blast of numerous tuyeres,
accumulates in the bottom of the crucible, whence it
is run off into a flat mould. By this operation it
loses a considerable portion of the carbon, and nearly
all the silicium, becomes very hard and brittle, and
its surface covered with small blisters similar to some
of the varieties of steel. In this state it is called
fine metal. It is broken up and transferred to what
'‘ iliillh 'numi'. '._,.
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Fig. 1233. THE REFINERY.
is called a purlcllingfin'mzee, in which the operation of
decarbonization is complete 1.


The refinery is usually built on a mass of brick-
work, about nine feet square, and the hearth is raised
only a small height-above the level of the floor. The
hearth 11,‘ Figs. 1233, 12341, is 2% feet wide, and 3%
feet long. It is formed by the junction of four cast-
iron troughs, I, through which a stream of cold water
is made to circulate, to prevent them from being fused
by the heat. The bottom of the crucible is of grit-
stone ‘or argillaceous sand, and is slightly inclined in
the direction of the tapping-hole 0. The air, which is
supplied by blowing cylinders, similar to Fig. 1223,
enters the hearth through the six tuyeres t, which are
inclined at an angle of from 25° to 30°, and so
arranged that the blast from each may be directed
towards the face of the opposite side of the furnace,
not in opposition to the opposite tuyere. The tuyeres
are furnished with double casings, through which
cold water is constantly running. A supply of water

Fig. 1234. PLAN or REFINERY.
is brought by a pipe 12 into the reservoirs e, whence
it passes to the tuyeres, through the pipes j, and
escapes through the tubes 0’ into the tanks 20, into
which the water from the iron troughs flows by the
syphon tubes 0. A furnace of this kind consumes
about 400 cubic feet of air per minute. This is sup-
plied by the pipes T, which are furnished with screw-
valves at s for regulating the supply. Above the
hearth is a chimney 16 to 18 feet high, supported by
four cast-iron columns, so as to allow free access to
the fire on all sides. The tapping-hole 0 is placed in
one of the shorter sides of the hearth, and by it the
melted metal and the slag" flow out into-the mould c,
where the metal is cooled by quenching with water.
The plate of fine metal thus formed is about 10 feet
long, 22‘- feet broad, and 2 inches thick; A thin crust
of slag forms upon its surface; but’ the greater
portion is collected in ‘a small pit at they lower end of
the mould. As soon as one ‘charge of - metal is run
out, the hearth is prepared for another. The work-
man first detaches, by‘ means of a long rod, any por-
tions of metal " that may be adhering to the sides of
the‘ furnace; 116 tllfin presses down the fuel, throws
‘man-ssh supply'ofcoke, and levels it to the proper
height: 1113011 this he *arranges six iron pigs, four
Pdl'allel t0 the. 1011?; Sides of the furnace, and two
across; The weight,_ which may vary from 20 to
30 cwt., ‘takes about two hours in refining, and the
- IRON-l, ,
loss is from 13 to 17 percent} In about a quarter of
an hour the‘ iron melts down, and falls in drops
through the blast to the bottom of the furnace. A
portion of the metal thus becomes oxidized, and,
uniting with the silica of the fuel, and also with that
formed by the oxidizing of the silicium of the metal,
forms a fusible vitreous slag, which, being rich in
oxide of iron, exerts a powerful decarbonising action
on the iron on which ‘it floats. To promote .these
changes, the blast is madeto play upon the fused
mass for a considerable time after the whole of the
iron has been collected at the bottom of the crucible.
During this time the fuel is lifted up by the motion
caused in the metal by the escape of carbonic oxide
produced by the reaction of the rich silicate of iron of
the slag. When the decarbonization is thought to
be sufiiciently advanced, the'hole 0 is opened, and the
metal allowed to flow into the mould. A considerable
quantity of cold water is thrown upon it, whereby it
becomes extremely brittle and sonorous. The slags
are then broken in pieces for the puddling-furnace.
About 10 tons ofcast-iron may be passed through
the refinery in the course of twenty-four hours, with
the consumptioniof from 4'.‘ to 5 cwt. of coke for each
ton of- metal' refined. _For the better kinds of iron,
such as that used. for the manufacture of tin-plates
and iron wire, where the, tenacity'of the pure metal
is required, coke is too impure a fuel; charcoal is
therefore used; but as with ‘this fuel the metal
collects into clots or lumps, they are formed into a
bloom which ‘is conveyed to the helve, and flattened
into thin plates, preparatory ;to being finished in
another furnace.
In the puddling-furnace, shown in sectional eleva-
tion and plan, Figs. 1235, 1236, the hearth A is of fire-
brick set on edge, or it is a plate of cast-iron, covered
with‘a layer of slag, which is made
to incline towards B, where there is
a considerable fall to allow of the
escape of the slags formed during the
process. of puddliug ; and they are
removed by the fl088/710Z6, ii. The
hearth is about 6 feet long and 4 feet
wide at the widest part, and taper


Fig. 1235. runnmxe FURNACE.
to about 20 inches towards the chimney.‘ It is heated
by a fire at F, from which it is separated by a bridge
6 10 inches high. The fire-bars are made movable for
the purpose of removing the clinkers ; and the draught
is determined, through the furnace, by a chimney from
30 to 50 feet high, furnished at the top with a damper, D,
which can be raised or lowered by means of a chain
and lever. The opening at n, which communicates

with‘ the grate, is usually closed by heaping up the coal
used for the fuel. The opening 1) communicates with‘
the hearth, or sole of the furnace, and is chiefly used
for working the metal with an iron bar during the
process of puddling. It is closed by an iron frame"
filled with fire-bricks, and is raised by a chain and
lever. Another opening nearer the chimney is used
for charging and for cleaning out thefurnace at the
end of an operation. The whole furnace is very
strongly built: it is encased with cast-iron, and held
together by clamps and wedges. The chimney is
also strengthened by iron ties.
The charge of fine metal is piled up on the sides of
the hearth, until it nearly touches the dome, the
centre of the sole being left clear for working the‘
charge, and allowing the hot air to circulate about it.
Aportion of rich slag andiron scales is added; the’
‘doors and the damper at the top are closed, and fresh
fuel is added to the fire. In about half an hour the
metal begins to melt and flow on the bottom of the
hearth. The man removes a small iron plate from a



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Fig. 1236. PLAN or‘ PUDDLING FURNACE.
hole in the working door, passes in an iron rod, and
stirs up the molten metal so as to expose fresh
surfaces to the oxidizing influence of the draft, and
moves it further from the bridge, to prevent the whole
of the charge from running together. 'When the
charge is brought into a uniform pasty mass, the fire
is lowered by gradually closing the damper, and, if
necessary, throwing a little water into the furnace.
The metal now, from the escape of carbonic oxide
gas, assumes the appearance of boiling, and the gas
burns at the surface with its characteristic blue
flame.‘ The metal is kept constantly stirred with. ‘an
iron paddle, so as to expose fresh surfaces to the

Fig. 1,237. PUDDLING.
action of the gases; the direct action of the atmo-
sphere is avoided as much as possible .by keeping the
working—door closed,.otherwise the metal would be
too much oxidized. By continuing to work the metal
88'
IRON.
i .1238-
-?i§§'i:t@i§feet-_-long, the weight of thehelve being about 3%
The axis a rests on heavy plummerblocks.
'1 by strong bolts passing-"through courses
it loses its consistency, and becomes sandy, or, as
the workman calls it, dry : the evolution of carbonic
oxide ceases, but the puddler continuesto work the
metal untilit appears uniformly granular. The fire is
then. gradually urged, and the increased temperature
causes the sandy particles to agglutinate ; the iron is
then said to work heavily. A portion of the slag is
run off through the flosshole, and the man then pro-
ceeds to ball weer to form the iron into balls. For
this purpose he attaches a small portion to the end of
his paddle, and, rolling it round, other fragments
weld on to it. When a ball of 60 or 7 0 lbs. weight
has been formed, it is detached from the paddle, and
another is formed in a similar manner. ‘When the
whole of the charge has been balled, it is moved into
the hottest part‘ of the furnace, by means of a kind
of rake called a d0__1ly,_._anjd the fire, is urged so as to
weld the metallic particles; Each ball is'then lifted
out of the furnace by means of. heavy tongs, and con-
veyed to the shingling hammer, or to the squeezer, .
where an iron rod is welded to it by way of a handle ;v
the slag is pressed out, and the metal consolidated.
The whole operation of puddling occupies about 2%
hours. At the end of - the first 20 or 25 minutes, the
metal begins to fuse, and in another hour is coin-
pletely reduced to a sandy state, in which it is kept
for another half hour, when the balling is commenced
and occupies about the same, time. From 10 to 11
charges, of 3-1,,- to 5 cwt. each,.>are passed through the
furnace in the course of 24: hours. The fine metal
loses about 9 per cent. in the puddling, and occasions
the consumption of about its own weight of coals.
The hammer used in compressing the balls is shown
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Fig. 1238. THE HELVE, on SHINGLING'HAMMER.
It is made of cast iron, and‘ is about‘




‘ V, anus into. a foundation of masonry- - The.
'7 .7 ' “in diminishithe concussion of the pen-1
deroiishlaééjli The head In is of wrought iron faced
with, steel,- andweighs from 7_ to 8 cwt: it is, passed
v_ .ja; hole_..in the helve and well‘ secured with
.1 V The pane of the hammer p as well as that
of" anvil'is formed into a series 6f grooves for the
i'_ _' pur'p use of better ~nipping Land? @compr'essing the lYball.‘
":“iThe face of the: anvil is supported-‘on? a-block‘ofiro'n
z‘ of about 4! tons weight._- .The head'is 'rai'se‘d'b'y'a
number of crime a, fixed. in. a heayy collar 13, called the
cam-ring day, about 3 ‘feet in diameter, fixed to a
powerful shaft s, which is.’ turned by steam or water
power. assisted and regulated by a heavy fly-wheel, a
portion of which is shown in the figure. In this
way the, head is lifted from 16 to 24 inches, and
makes from 75 to 100 blows per minute. l/Vhen it
is desiredto suspend the operation of the hammer,
the rod 12' is pulled, this brings into a vertical
position the prop p, which supports the hammer and
keeps it free of the cams. ~
The squeezer, which sometimes takes the place of
the hammer, is. shown in Fig. 1239. It consists of two
‘- , "r‘
\











a:
>..
_-.=





E















Fig. 1239. THE saunnznn.
powerful jaws a 6, united at c, as in a pair of shears :
the meeting faces of the jaws are furrowed with
numerous. grooves in order to hold fast the bloom.
Thelower jaw b is hollow to allow a _current of water
to flow through it to keep it cool. The upper jaw is
set in motion by the shaft, and the crank Ir worked
by the fly of which a’ is the centre. This press is
said to squeeze out the slag more thoroughly and
there is'a difference of opinion among iron masters.
Nasmyth’s steam-hammer has also
the same purpose.’ . ~ _- - -
and while it is still at a red‘ heat, itis ipassed between
cylinders or rolls; Fig; 12410, which‘se‘rve to compress
and weld together the/metallic -Ypai~ti'cles', to express
the last portionsof the slag, anfd-t'ol’draw out the iron
into'bars». .Two set-s of rolls’. areusuauy employed,
the one called mug/ring rolls, which prepare the iron
for the finishing; rolls, ‘the latter being differently
grooved according to the section intended'to be given
to the bar: The rolls Bit/MR”, are mounted one
above the other in pairs in amassiveiron frame-work
a a, connected by heavy couplings at e,,"tight-ly screwed
together. Motion is communicated by strong ‘toothed
wheels made to turn either way, and the distance
between the rolls is regulated by screws sis, attached
'to the bearings ‘in which the trunnions work.
bearers b are connected at the upper part by stout iron
bars, which are used to support the heavy tongs used
in lifting- the blooms. " Below the roller frame is a
channel througliwhich stream of water flows, and
in it is collected the scale which 'falls from the surface
of the heated "iron" while ‘passing through the rolls;
and a stream water “made to vplay from a small
‘pipe ti'upon' each pair, of rolls to keepthem cool. The
w.1101e-{ arrangement rests upon a massive foundation

expeditiously than the helve does, but 011 this subject‘
been applied to'
As soon as the slag i's pressed- out of the bloom,
The -
of timber, :‘masonry "and cast iron. ’ The ‘roughing’
IRON.
rolls are about 5 feet in the clear between the bearers,
and 18 inches in diameter. “ Each of these rollers
has a’ series of from 5 to 7 regularly decreasing
grooves of an elliptical form, so arranged that the
shorter axis of the figure formed by the meeting of
the corresponding grooves in the two cylinders is
equal to the longer axis of the ellipse formed by the


a.._.-










junction of the two grooves which come‘ nextv in;
succession. The smaller axis of each ellipse is also
invariably prependicular to the surface of the two
cylinders, by the meetings of which it is formed; and
this reason, every bar which has passed between:
the rollers, is made to describe a quarter revolution.
before it enters the grooves which come next in the
H2
O
"1























a?” . --__._; ,, . M _ Mn - , 7T7‘? The.“ “ht-“s I:~“‘- .. .. an i:


Fig. 1240. ROLLS.
series, and is thus equally compressed and drawn out
in all its parts.” The roughing and preparing grooves
are usually arranged on distinct rollers, as in the
figure, where nu’ represent the roughing rolls, and
n” n’” those for forming the metal into bars, which are
afterwards cut up by the shears, formed into faggots,
welded together and drawn into bars of the required
section. The first 3 or 41 grooves of the roughing
rolls are roughened with teeth to cause the iron to
pass through without slipping; and on a level with
the bottom of the notches on the lower roll is a thick
plate of cast iron, called an apron, for supporting the
balls or masses of iron which are to be passed through
the rollers.
The iron produced in this way is hard and brittle,
and subject to flaws and imperfections. It is well
adapted to railway bars, which are prepared by passing
the bloom of puddled iron through grooved rollers of
the section of the bar required. Good bar iron is,
however, prepared by a separate process already
indicated and now to be described. The bars from
the roughing rolls are first cut up into short lengths
by the shears, represented in Fig. 1241, consisting of
two jaws, to'which are firmly bolted cutting edges a 6
' of hardened steel. The
lower blade is fixed, but
the upper one moves on
a stout pin r, and is at-
tached by a lever 12 n to
_ a rod n M, which is con-
nected by a crank to the
shaft of the steamsen-
gine, so that at every
revolution of the axle
by which the power is
supplied, the jaws of
the shears are made to open and shut alternately.
Bars of an inch or more in thickness are easily
divided by the jaws.
A number of the short lengths thus produced are
piled or faggoted together in a reverberatory furnace,
which differs chiefly from the paddling furnace in


Fig. Jill's-Leashes.

having a larger grate in proportion to the hearth, a.
more intense heat being required. It is important to
preserve the faggots from the oxidising influence of
the air, so that no air is allowed to get to them, ex~-
cept that which has. passed through the grate. When‘
the faggots have attained the proper welding heat, they
are taken out one at a time and thrown to the men at;
the finishing rolls, who pass them through the grooves,
as rapidly as possible, so as to get the required section.
and dimensions before the bar has cooled below the
proper temperature for drawing. The finishing rolls
are formed much more accurately, and revolve at a
much higher speed than the roughing rolls. The
latter make about 70 revolutions per minute: rolls
of medium size about MO, and small rolls 230 or 240.
The grooves gradually diminish in size, and the bar is
passed from one to the other until the required size.
is attained. For small bar iron, 3 rollers placed one
above the other are sometimes employed._ Motion
being directly communicated to the centre roll, this
by means of cogged wheels causes the other two to
revolve in contrary directions. The heated bar is.
passed between the first and second rolls, and then.
returned from the other side between the second and
third. Sheet iron is made by passing the metal
between smooth-faced rollers, which are gradually,
screwed nearer together as the desired thickness is
being approached. Two sets are used 5 in the vfirst
the metal is roughed, and in the second finished off,
and the surface made even and polished. The metal.
requires a reheating between the processes. The
sheets intended for the manufacture of tin-plate are
polished by being subjected to hydraulic pressure
between two smooth surfaces of cast iron.1
The short lengths which compose the pile, tend to
(1) At the Breslau Exhibition of the Works of Industry, (1852,)
some of the sheet~iron excited great attention; 7,040 square feet
being rolled from ahundredweight of iron. This would give a
thickness of about Elfath of an inch. It was proposed to use this
leaf-iron as a substitute for paper. A bookhinder of Breslau exhi~
‘cited an album made of it, and the iron pages turned as flexibly as
paper. 2 is proposed to print for the tropics on these metallic
leaves, and thus render books secure from the ravages of the white
ant.

90
IRONI
produce a fibre in the bar, which in’ good iron is‘
always perceptible however perfect the weld. In
rolling flat bars, the layers of the pile are kept
horizontal, in order that the fibres may be as straight
and parallel as possible. The experienced blacksmith
inworking up his bars-always attends to the direction
of the fibre, because by doing so he. can make the
most of his iron and increase the strength and tough-
ness of the articles produced. I
Bar iron is ‘known in the market by the names *
common irori, test iroa, test test or ol'zaia-oatle iron.
The different kinds of iron used in the manufacture
of gun—barrels are described under GUN.
Two common defects of bar iron are known as red
short and cold sltort. Red short iron is that which
cracks when bent or punched at a red heat, although
it may be sufficiently tenacious when cold. Cold
short iron on the contrary is weak and brittle when
cold, but can be worked without difiiculty when hot.
The quality of a bar of iron may be tested by nicking
it at one side with a chisel and then breaking it or
doubling it down at the notch. If the iron be cold
short, it will break off at once with the blow of a
sledge-hammer. But if the bar be of good quality, it
will not break off but bend double, and those portions
of it to the depth of the notch on both sides will
separate a little from the body of the bar, and split
up like a piece of fresh ash stick, exhibiting a clear,
distinct, silky fibre. If this appearance be produced
on a cold bar, and it be then raised to a cherry red
heat and bent first in the direction of the pile, and
then at right angles to it without cracking on the
outer side of the bend, it is of excellent quality, neither
red-short nor cold-short. A very small amount of
phosphorus will make bar iron brittle, so small a pro-
portion as 05 per cent. having been found to make it
cold—short. Sulphur has been assigned as the cause
of the red-short property of wrought iron; the
presence of only 00001 of sulphur renders the iron
very difficult to work at a welding heat. A cold-short
iron is generally produced from a lean ore, in which
case it has been found desirable to mix with it the
rich red hepatic ore of Lancashire and Cumberland,
which if smelted alone would produce red-short iron.
In this way two opposite defects are made to correct
each other, and iron of average strength is produced.
Sncrron VIL—Tnn Mxlvurxcrunn or STEEL.
Iron in its pure form is known only to the scientific
chemist; in its manufactured state it is never entirely
free from carbon and other substances. The carbon
appears to be only mechanically mixed with the metal,
a peculiar process being required to effect a chemical
union between the two, the result being a earturet of
iron or steel. Less than 8 per cent. of carbon
chemically combined with iron develops those remark-
able properties which distinguish steel from iron, and
adapt it to purposes for which iron is inadequate.
Thus steel is so much harder than iron that it will
cut and file it; steel will scratch the hardest glass;
strike sparks with siliceous stones ; it is denser than
iron, has a finer grain, assumes a brighter and whiter

lnstre- when polished, acquires greater elasticity,-
retains magnetism more permanently, and does not-
rust so easily. When heated it assumes various
beautiful tints of colour, and if suddenly cooled it
becomes harder, more brittle, and less pliable than
iron. Indeed the chief value of steel depends upon
the ease with which it can be hardened and tempered
to any degree between extreme hardness and soft-
ness.
Ordinary wrought iron-may~ contain about 025 per
cent. of carbon without having that property of steel
whereby it becomes hard by- being suddenly cooled in
water: but with 0'50 to 060 per cent. of its weight
of carbon, it emits sparks on being smartly struck
with a flint. But the quantity of - carbon required to
render iron steely, depends greatly on the purity of
the metal; shear steel after tilting contains from 1 to
1'5 per cent. of carbon: with more than1'7 5 percent.
the steel cannot be welded. Iron with 2 per cent. or
carbon cannot be forged; but with 19 per cent. of
carbon iron may with care be worked under the
hammer; and this appears to be the extreme point of
carbonization beyond which steel is converted into
cast iron.
A pure iron is required for the manufacture of
steel, such as the charcoal iron of Sweden and Russia.
A similar iron made at Ulverstone, and one from
Madras, are also used. The foreign iron is imported
in bars, on which certain marks are stamped by the-
manufacturers, and which distinguish it in the market.
The most celebrated iron mine of Sweden is that of
Dannemora, about 30 miles to the north of Upsala.
The ore contains limestone, quartz, and actinolite,-
and affords from 25 to 75 per cent. of cast iron, which-
is as white as silver, crystalline, and very brittle. It
is converted into malleable iron by heating in a bed--
of charcoal, and hammering out into bars, in which‘
state it is whiter than common iron, less liable to
rust, and distinctly fibrous in texture.
known at Hull (the English port to which it is ship-
ped) by the name .of Oreyraad iron, from the name of
the port at which it is shipped.
The marks which distinguish QT" 00 ii’ -
this iron are the 7200]) L, (so ‘is? ‘swig W
called from the letter L in- .Fig. 1242.
closed in a hoop); the G L, and the double [/allet.
Inferior Swedish iron is known by the marks 0 and
orozorz, D and crown; the Sleiatacle, and the W and
erozorzs. All these marks are shown in Fig. 1292.
It is remarkable that steel is produced on the con-
tinent of Europe by a process directly the reverse of
that followed in England. We manufacture steel by
the addition of carbon to pure malleable iron by what
is called the process of oemeritatioa. In Germany,
Styria and Silesia steel is made by depriving some of
the better kinds .of cast iron of - the excess of carbon
contained in them, one portion being got rid of by -
oxidation, while another portion is made to combine
chemically with the fused mass.
The oerr'zerztilzgfiirrzaee in which iron is converted
into steel in this country is shown in section Fig. _
Externally it resembles a glass-house, and»
1243-.
This iron is '
IRON.
91'
consists of a cone or'hood 30 or ll0 feet high, serving
to shelter the furnace within and also to carry off the
smoke of the fuel. Within the furnace are two chests
or troughs, e c, in which the bars of iron. to be con-





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Fig. 1243. SECTION or cemnnrrse runnacn.
verted are buried in pounded charcoal. These troughs
are made of fire—tiles or firestone grit, and are capable
of holding from 8 to 12 tons of bar iron. They are
from 8 to 15 feet long, and from 26 to 36 inches in
width and depth; but those of small capacity are said
to produce the most uniform quality of steel. Below
and between the troughs, and extending their whole
length, is a grate, F, open at each end, where it is
supplied with fuel, and the fire is kept up as equally
as possible during the process, the flame being di-
rected equally round the troughs by a number of air
holes and fines, 0 0, leading to the chimneys. The
draught is further aided by an opening in the middle
of the arch of the furnace. The troughs are, of
course, filled before the fire is lighted, (the workman
entering the furnace by the opening under 11,) and the
preparation of hard charcoal dust, called cement, varies
with different steel converters: charcoal made from
hard wood is preferred; but soot is sometimes used;
as also a proportion of ashes (about 713th) and a little
common salt.1 The workman sifts this mixture to
the depth of two inches over the bottom of the
troughs; puts in the bars upon their narrow edges,
with a space between every two bars of from half to
three quarters of an inch ; powder to the depth of an
inch is then sifted over this layer; a new series of
bars is next made to fit into the interstices between
the first, care being taken that no two bars are in
contact, and in this way the troughs are filled to
within 6 inches of the top. The filling is then con-
tinued with old cement powder, and this is lastly
covered with refractory damp sand or fire-tiles, for
the purpose of excluding the air, which, if admitted,
would greatly injure or altogether stop the process of
cementation. The entrances to the furnace being
carefully closed, the fire is lighted below the troughs
and carefully urged for two, three, or four days, until
the proper cementing heat is attained: this heat is
maintained during several days more until the iron
has absorbed the quantity of carbon requisite to form

(I) The use of ashes and salt in the cement has not been ex-
plained. Mr. Phillips suggests that the salt may tend to vitrify
any siliceous particles contained in the charcoal, and prevent their
entering into combination with the iron under process of carburi—
zation. '

the kind of steel required by the manufacturer. From
six to eight days are sufficient for the production of
moderately hard steel—such, for example, as that
known by the name of clear steel; softer steel, for
saws and springs, requires a shorter time; harder
steel, for making the chisels used in cutting iron, takes
a longer period; and for some purposes bars are ex”
posed to two or three successive processes of cementa-
tion, and are hence said to be mice or l/n'z'ce eon-
verleal. -
.In the centre of the end-stones of the cementing
troughs are small holes, called tasting lzoles, cor—
responding with small iron doors in the outer brick-
work; by these holes the workmen can occasionally
draw out a bar to see how the transmutation is going
on. This is judged of by the blisters which appear
on the surface of the bars, which give the well-known
name of ll-z'slererl sleel to this article. When by this
process of lasting the change is judgedto be complete,
the fire is extinguished and the furnace left to cool
for about a week, when the process -for making
blistered steel is finished.
This steel is very different from the bar iron from
which it was produced. Its surface is coveredwith
blisters, and on breaking a bar across, its texture is
seen to be no longer fibrous, but granular or crys-
talline; the colour is white like frosted silver, and the
crystals are large in proportion to the amount of
carbon absorbed.
The cementation of steel may be effected by ex-
posing the iron at a proper temperature to the action
of carburetted hydrogen gas. Steel of excellent
quality may be produced in this way, but the process
does not appear to be sufficiently economical to admit
of its being generally introduced. It has also been
proposed to convert the retorts used in the manufac-
ture of coal gas into cementing troughs: the bars of
iron to be put in with the charge of coal, and taken
out with the coke, or after a second charge of coal
has been coked.
TILTING. The bar of blistered steel contains nu-
merous fissures and cavities, which render it unfit for
forging except into a few rough articles. To prepare
it for forging into edge-tools and cutting instruments,
it requires to be condensed and rendered uniform,
which is the object of the next process, called shearing,
the clear steel thus produced being originally em—
ployed in the manufacture of shears for cutting off
the wool from sheep.1 The process is also called
lz'llz'ezg, from the circumstance of a tilt hammer being
employed.
In some respects the operation of tilting resembles
that of sliz'aglz'ng described in the manufacture of iron ;
but the tilt hammer is differently arranged. In
shingling, where only a slow motion is required, the
hammer is lifted up by means of levers attached to a
cam revolving under the nose of the helve. In the
tilt hammer the cogs of a wheel are made to act on
the tail of the helve, pressing it down, and thus
(1) Shear steel is also sometimes called Newcastle steel, from the
circumstance of steel of this quality having formerly been made
at Newcastle; abezter quality introduced from Germany gave rise
to the term, German steel.-

22
IRON‘.
causing an elevation of the head of the hammer, and
a rapidity of motion, which could not evidently be
produced by the arrangement of the shingling ham-
mer; for, in this, the levers must be sufficiently wide
apart, to allow the hammer head a clear space to fall
through. In the tilt hammer, however, where the
motion is applied at the tail, the number of levers
may be considerably multiplied; because, from the
position of the axle, the tail describes a very small
are between every two levers; and this small motion
will cause the head to pass through a much larger
space in the same time, thereby producing rapidity
of motion, and considerable force. The construction
of the tilt hammer will be better understood from
Fig. 12414:; The frame work is strongly secured to
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1.5
"r g hem / r></\/><1><r/dxi/\s*
Fig. 1244. Tim: HAMMER.

the masonry and timber of the foundations, so as to
form a firm bed for the block. The shaft of the
hammer is made of timber secured by wrought iron
rings and fitted into a cast iron socket with trunnions
or axles cast upon it, which turn in brasses in a block.
The wheel 0 by which the hammer is elevated is fur-
nished with ears or armpits, which, during the revolu-
tion of the wheel, engage the end z‘ of the shaft and
continue to depress it until disengaged, when the
hammer head h falls with considerable force on the
anvil, producing in this way from 150 to 360 strokes
per minute.
The blistered steel is prepared for tilting by break-
ing the bars into lengths of about 18 inches, and
binding four or more of these into a faggot by means
of a slender steel rod. One of these fragments is
left longer than the rest to serve as a handle, or a
a - r ' pole of iron is
used for that
_ Fig' 1245' purpose, as is
shown in Fig. 1245. The faggot is then raised to a
welding heat in a wind furnace, and is covered with
sand, which combining with a small portion of oxide of
iron, forms a fusible slag over the metal, and prevents
it from wasting or burning away. When first removed
from the furnace it is placed 1111(161.‘ a forge hammer,
which unites ‘all the fragments and closes up internal
fissures. The rod thus produced is again heated, the
binding rings are knocked off, and the tilt hammer
comes into operation. The workman is seated on a
board, suspended by iron rods from the ceiling of the
mill-house; whereby he is enabled with a very slight
motion of his foot to advance or recede with ease and
rapidity, so as to cause every part of the bar to receive



the blows of'the hammer in quick succession. As the
anvil is nearly on a level with the floor, the workman
is seated in a kind of pit excavated for the purpose;
he is attended by two boys to bring hot rods and to
remove them after they are hammered. “ In small
rods, the bright ignition originally given at the forge
soon declines'to darkness; but the rapid impulsions
of the tilt revive the redness again in all the points
near the hammer; so that the rod skilfully handled
by the workman progressively ignites where it advances
to the strokes. Personal inspection alone can com-
m unicate an adequate idea of the precision and celerity
with which a rude steel rod is stretched and fashioned
into an even, smooth, and sharp-edged prism, under
the operation of the tilt hammer. The heat may be
clearly referred to the prodigious friction among the
particles of so cohesive a: metal, .when- they are made
to'glide so rapidly over - each other in every direction
during the elongation and squaring of the red.”
A visit to the tilt house is by no means pleasant
to a stranger; several hammer heads, each weighing
from 150 to 200 pounds, falling from three to four
hundred times per minute upon solid metal anvils,
a, Fig. 12%, produce a stunning noise and a vibration
which can be felt through the whole body. This
vibration is checked as much as possible by carrying
the foundation of the tilting apparatus to a depth of
ten or twelve feet, forming a heavy mass of masonry ;
and the anvil is made to rest on a massive wooden
pillar B, strongly secured by wrought iron rings,
which is supported by, and forms part of the masonry.
By tilting, the steel is formed into bars of about an
inch and a half broad, and three-eighths of an inch
thick; all the loose parts and seams of the blistered
steel are closed, and it is now capable of being
polished, which could not be done before: it is also
more malleable, and can be forged with the hammer
into shears, edge-tools, and cutting instruments.
The value of the steel increaseswith the amount of
tilting which it receives : it is therefore not uncommon
to cut a tilted bar into several pieces, form them into
a faggot, and elongate this again into a bar or rod.
The terms double shear, single shear, and half shear,
express the amount of doubling and welding which
the bars have received.
Oxs'r STEEL. Steel is produced in the greatest
perfection by the process of cashing; that is, the bars-
of blistered steel being broken into fragments, are
melted in crucibles and then poured, while in a fluid
state, into ingot moulds. The heat required to pro-
duce this fusion is very great, so that the crucibles-
or melting pots require to be made with refractory
fire-clay and with the greatest care, in order to ex-
clude bubbles of air and extraneous substances, which
might expand or ignite in the furnace, and thus
endanger the stability of the melting pot. '
The crucibles are made of Stourbridge clay mixed
with one half of an inferior clay from Stannington, near
Sheffield: a small quantity of coke dust and of frag-
ments of old pets is added, and the whole is kneaded.
into a perfectly uniform and smooth mass. The clay
is first mixed with water, worked up, and then spread
IRON;
out in a thin layer on a shallow trough on the floor.1
There it is kneaded during five or six hours by the
naked feet of two men, who with a shuttling kind of


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_ Fig. 1246.
TREADING OUT THE CLAY, AND MOULDING- THE
CBUCIBLES.
motion go over every part of the surface, pressing it
down quite flat; and so sensitive is the touch of their
feet, (which are developed to an enormous size by this
constant exertion,) that they can, by the difference
in the tread, detect an air bubble, a fragment of straw
or of dirt in the clay. The two latter they pick out
with the fingers, and get rid of the air by making a
slight incision with a knife. When the whole surface
has been well trodden over, it is folded double and
trodden out again so as to occupy the whole of the
trough. If the reader has ever watched the domestic
operation of making pastry, he will be able to form
a good idea of the process of kneading clay for the
steel-melting pets.
The crucibles are about two feet in height, and of
the shape shown in. section, Fig. 1249. They are
formed in a cylindrical mould of cast iron (4 a’, Fig.
124.7, which is open at the two extremities. This
cylinder is inserted into a sole of cast iron [2 I)’, firmly
attached to a block of wood and having a raised
circular edge. In the centre of the sole, correspond-
ing with the axis of the cylinder, is a hole intended to
receive the supporting rod of the inner mould c.
This consists of a block of hard wood, the surface of
which corresponds with the interior shape of the

(l) Stourbridge clay contains—-

Silica 46'1
Alumina 38'8
Combined water, and combustible and
volatile 12'8
Carbon 01-5
992

Hence, the only fixed principles of Stourbridge clay are silica
and alumina. The Srannington clay contains small portions of
manganese and lime, and a trace of oxide of iron. The melting
pots fuse into a vitreous enamel of extreme hardness. They can
only be used for three meltings, but if made of Stourbridge clay
alone, they will stand six.

: crucible: through the centre of this block- passes strong iron axis, the lower end of which rests in the
hole already mentioned; the upper end, which is
rounded, rises just above the circular cover of wood
66’. It will be seen that when the inner mould c is
in its place, as in Fig. 124?, there is between its
surface and the inner surface of the outer mould a
vacant space of the form and dimensions required for
the melting pot. The surface of c and the inner
surface of at having been smeared with oil, a quantity
of clay is put into a, and the central plug a forced
down as far as itwill go by hand: its further descent
Emu mmmligfl
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Fig. 124?. Fig. 124-9.
is then urged by blows of a hammer upon the rounded
head of the iron axis, until the lower. end of the axis
passes into‘the hole in the sole 5. In order to dis-
engage the moulded clay, the central plug a is pulled
out and the hole -in the centre stopped up: the
outer mould with its contained clay is then lifted
upon a block of wood mounted upon a stout iron rod,
Fig. 12418, and of somewhat less diameter than the
bottom of the pot, so as to press entirely upon the
clay bottom when the mould a a’, lifted out of b 6', is
placed upon the top of Fig. 1248. The mould is
then allowed to descend slowly and with care, by
which means the clay pot is left upon the top of the
block of wood, while the mould an, on reaching the
ground, surrounds the rod, Fig. 1248. The upper
part of the clay is then finished by hand : it is pressed
slightly inwards and made to assume the form, Fig.
1249. The blocks on which the pots rest are short
cylinders of clay: the covers, also of the same mate-
rial, are thick discs slightly raised in the centre.
Each crucible, which weighs about 25 lbs, is removed
as soon as it is finished into a heated vault, where
it gradually becomes dry; and some hours before
being used the crucibles are brought to a red heat
for the purpose of annealing them. A crucible can
seldom be used for melting the steel more than three
times without cracking; so that there is a constant
demand for crucibles, as many as 108 being required
per week for a ten-hole furnace.
On alevel with the crucible-making department are
the furnaces for melting the steel; these are ordinary
wind furnaces placed in connexion with a tall chim-
ney by which a strong natural draught can be obtained.
(See Fig. 1250.) Each furnace is only just large
enough to contain two crucibles and the proper amount
of fuel; and it is lined with a plaster calculated to
resist the intense heat. This plaster is formed of
the dust of the roads in the vicinity of Sheffield,
and is called gam'sz‘er. The fuel employed is a dense
well-made coke, broken into lumps of about the size
9%
rnon.“
of a hen’s egg. Immediately over each furnace‘ is
a trap-door, made of fire-bricks fastened in an iron
frame opening into the casting house, which is‘ a
kind of shed entirely open on one side, while on the
other ten trap-doors are seen, from the sides of
which escape a few rays- of red light indicative of the
fiery furnacesb<~ilo"w-_.'v In- an? adjoining shed the bars
of blistered steel -~ are broken ‘into fragments, and the
charge 5 for eachi‘crueible', about 30 lbs., weighed out
intov tin trays, a small portion of black oxide of
manganese being added to each-‘charge, thisqsubstance
being supposed vto improve the " quality of the. steel-.-
In some-cases powdered charcoal forms] part of the
charge... 1250 SliQW-Sfthe- interior ofithe casting
house. au'dlof the airwault, with ‘ two; crucibles, as


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Fig. 1250'. C'AS'TING HOUSE AND AIR. VAULT.
they are arranged‘in- the furnace ; a portion of the tall
chimney is also seen in section: on the shelves of the
casting house the green crucibles are left to season‘.
The empty crucibles are put into the furnace upon
a sole of baked fire-clay, and the charge is given to
each by means of a long funnel of iron plate. Each
pot is carefully covered over with a lid of a more
fusible clay than the body of the crucible, and some-
times a small quantity of bottle glass or blast furnace
slag is put in above the steel fragments, so as to form
a sort of vitreous coating to prevent the air from
oxidizing the metal; When; the pots ‘are thus charged
and covered in, the furnace is filled up with coke and
kept well supplied. In about four hours the steel is
in a state for casting; and as the time approaches the
men occasionally lift up the various trap-doors‘ and
examine the crucibles, their" eyes being accustomed
through the fierce floods of heat which pour upwards
from the furnace to detect the precise time when the
metal is sufficiently fluid for casting.
While the steel melting,"v the ingot moulds are
prepared. Th'ese moulds‘, which are of cast iron, are
of‘ various sizes, according to circumstances; those
which were used at the time of the writer’s visit pro-
ducing an ingot about two inches square, and two
feet in length, a quantity equal to the ‘contents of one
crucible. When an ingotv of unusually large size is
required, such as forrrrolh'ng into a piston-rod or a

large plate for a circular saw, the mould is, of course,‘
of proportional size, and receives the contents of two
or more crucibles. Each mould consists of two
parts, forming a long hollow cavity, the parts fitting
accurately





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pit. in? the‘ floor ‘house. Previous to
putting the -‘ the interior is smoked
by being laid'lalcl’os‘si'alp'itch; ‘the internal . coatin g‘ of
carbon thus impartedipreventing the liquid steel from
adhering to. or melting the-mould.
Just before drawing the crucibles, each man puts
on sacking leggings, and an apron of the same mate-
rial; he next visits a tank, and thoroughly soaks
these in water, as a further protection against the
fierce heat to which he is about to be exposed; then,
throwing open the trap-door of‘ one of the furnaces,
he removes a portion of‘ the white hot coke, and,
planting his feet one on each side of the yawning
fiery furnace, thrusts ‘down a pair of tongs,
Fig. 1252, furnished with concave jaws for
grasping the crucible just below the swell,
and then, with a motion between a jerk and
a swing, raises the glowing burden. A- se-
cond man immediately removes the cover;
a third man, and the most skilful, grasps
the crucible with tongs held horizontally,
raises it, and slowly inclines it to the
mouth of the ingot mould, his attendant
with a pair‘of tongs removing any portions
of cinder or slag from the surface of the
molten metal. Considerable skill is re‘
quired in teaming, as the operation of trans-
ferring the metal from the crucible to the
ingot mould is called. It must be poured
directly down the centre of the mould,
without touching the sides; for were‘ it to
do so, it would instantly remove the carbo—
nace'ous covering, and burn a piece out of Fig‘ 12
the mould- The metal flows as liquid as water, and
with the gurgling sound of water if poured under
similar circumstances; but the extremely high tem-

' perature of the molten steel is shown by the white heat
slightly tinged with blue. As the stream falls, minute
portions ‘of it combine rapidly with the oxygen of the
air, and take fire, producing brilliant scintillations.
The fire even communicates itself to the ingot
towards the end of the process of teaming, and the
mould then appears like a brilliant firework; but this
combustion is soon stopped by the insertion of a
solid plug. As the ingot immediately solidifies, each
mould is opened directly after the teaming, and the
, IRON—IRRIGATION .
95
ingot is turned out in a red-hot state. This rapid
cooling of the steel and the thin film of soot effec-
tually protect the mould from the destructive action
of the liquid metal which would otherwise ensue.
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The men engaged in these operations have that
peculiar look about the eyes which shows the nature
of their occupation; but otherwise, we believe, the
business of steel refining is not considered unhealthy,
and the men receive good wages.
As soon as the crucible is emptied of its contents,
it is returned to, the furnace, to
receive a fresh charge; and as four
hours are required for the melting,
there are three casts in the twelve
- hours during which the men work.
The charge is introduced by means
of a funnel of plate iron, Fig.
1254, into which a rod is inserted,
to break up the charge, and pre-
vent a heavy mass from falling at
once into the crucible, which might
cause its fracture.
Cast steel is much denser and
harder than tilted steel, but it re
quires care in forging, because a
little above a cherry red heat it is very brittle. Two
surfaces of cast steel may be welded together by
interposing a thin film of borax; and cast steel may
be firmly united to a polished surface of iron by
placing the iron in the mould into which the steel is
poured. The two metals can then be rolled and
worked out together into reds adapted for forging.1
Fig. 1255 shows the operation of rolling steel. It
(1) Various particulars respecting the forging, hardening, and
tempering of steel, are given under CUTLERY. See also An-
NEALTNG—-CA_SE nnnnnnrne, 8:0. The damasking of steel is
noticed under Gun. In this notice of the manufacture of steel,
we have availed ourselves of information contained in the Editor’s
work on the “ Useful Arts and Manufactures of Great Britain.”
The pictorial illustrations are from drawings made for the purpose
by Mr. Prior, at Sheiiield. The reader interested in the manufac-
ture of steel, will do well to. study the elaborate memoirs on this
subject, by M. F. Le Play, in the Fourth Series of the Annales des
M'ines. The memoir contained in vol. iii. 1843, is devoted to the
fabrication of steel in Yorkshire, while that in vol. ix. 1846, is on
the fabrication of steel in the north of Europe.



does not differ greatly from rolling‘ iron, and there-'
fore need not be further described.
When steel is moistened with a drop of dilute
eater-‘villi’
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. Fig. 1255. ROLLING STEEL.
nitric acid, a dark grey spot is produced: malleable
iron so treated yields a spot of. a green colour.
When steel is fused with very small quantities of
platinum, of silver, rhodium or iridium, its hardness-
is greatly increased; but these alloys have not yet
been used in manufactures.
Sheffield and its ‘neighbourhood is the great seat of
the steel manufacture. The annual quantity of steel
produced during the last 5 years, varies from 16,000
to 17,000 tons from foreign iron, and from 1,500 to
2,000 tons from iron of British manufacture. The
number of converting furnaces is upwards of 120,
each of which is capable of converting weekly 6 tons
of iron: the coal consumed in the process is about
equal to the weight of steel produced. There are
also above 100 melting furnaces for cast steel, each
containing about 10 holes for crucibles: ll tons of
coke are used in making 1 ton of cast steel, and each
furnace of 10 holes produces ‘lg- tons of cast steel
per week.
IRRIGATION. This art, as practised in warm.
countries, has been noticed in our article DRAINAGE,
to which with its illustrations we refer the reader, but
the mode of irrigating an English water-meadow is
essentially different. In the East it is the ordinary
custom to introduce water on the soil, and leave it in
a stagnant condition for months, the water thus
afi’ording a valuable and necessary protection both to
the soil and the tender plants, from the effects of the
great heat. But in our own country, where no such
necessity exists, great care is taken that the water
shall not accumulate on the soil so as to become
stagnant, while at the same time it shall be supplied
in ample quantity all the time the plants are growing.
Hence in our best systems of irrigation, the draining
is as essential as the flooding, and while one set of
channels is made to distribute the water slowly and
regularly over the meadow, another set is devoted to,
the opposite purpose of carrying it off. Thus a con-
stant flow of the water is maintained, accelerated or
retarded by small hatches, so as to keep it at the de-
sired level. The feeders, or channels which supply the
96
IRRIGATION—180 OHRONISM -—I'SOOHRONOUS.
water, are formed on the top of low ridges, the drains
in the holliows between them, and this further aids in
keeping up the ‘flow of the water.
In preparing to irrigate lands, the first step is to
take the level,‘ Iand‘to'r' ascertain what are the supplies
of watertowibe' obtained above that level, and whether
swamp-plies are available without deteriorating the
propertyiiofii'.ethers,"or withdrawing water from some
nse-relsewhere. If no natural supply of
~' be‘ ""obthii'led-iab‘ove the'level, and if water
cannot. beraenduetéu~ ‘to; a reservoir for the purpose,
' of the ‘land is impossible. On the
othéhh'anfl; ihjdoe'smot follow as a matter of course
thatéii'every'flew land where ‘a supply of water can be
readily: obtained is‘ capable of irrigation, for there
must‘also be" the means of carrying off the water, as‘
well as of bringing it on.
The mosti: general- and natural position for water-
meadows i's-1_on~~the banks of running streams. At
some point in the course of the river a canal is dug
along the bank, and carried perhaps to a considerable
distance fromv the river. Into this a portion’ of the‘
water‘ is diverted which will keep the same level as
that part of‘ the river where it has its origin: in
' ' some cases a
\/_ dam D, (Fig.
' 1256), . is
. constructed
‘ across the
‘ river 3, so
as to se-
. cure a large
" - quantity of
water at the
- - ' Fig, 11256.. most advan-
tageous time "for irrigation. A certain command of
water being; thus obtained, ‘it is directed into a main
channel or conductor- a, in connexion with various
smaller channels’ or feeders. From these the water
overflows into- the drains with which they are inter-
sected, and which carry‘ it into‘v the main drain h, whence
it is conveye'dlback again to the river, unless there be
other lands at a lower level to which it can be
transferred, when the‘ main drain in its turn becomes
a conductor-to a second system of feeders, and so on.
But this method, which is called calchworh, is only
available when there is a considerable fall of water,
and a gentle" declivity towards the river. It is also
only desirable when the supply of water is limited,
for its fertilizing qualities rapidly deteriorate. i
The best season for‘ irrigation is not always that in
which the‘ heat and drought are the greatest. In
fact, at such season, much mischief would be done by
iujiidieious flooding, while in the depth of winter,
when_._ it might; be supposed that watering is needless,
valuable results ‘are often obtained from the practice.
‘0‘ During frost,” says an experienced writer, “ when
all dry meadows are in a state of torpor, and the
vegetation is suspended, the water-meadows, having
‘a. current i'of'water continually flowing over them, are
protected-from the effect of frost, and the grass will
continue to grow ~as long as the water flows over it.
v I



--—9-'
Too much moisture, however, would be injurious, and
the meadows are therefore laid dry by shutting the
flood-gates, whenever the temperature of the air is
above freezing. By this management the grass grows
rapidly at the first sign of spring. Before the dry
upland meadows have recovered the effects of frost
and begunto vegetate, the herbage of the water-
meadows‘is already vluxuriant. As soon as they are
fed off,'or cut for the first? crop of hay, the water is
immediately put on again, but for a shorter time; for
the warmer the air, the less time will the grass bear
to be covered with'water.
appears, and the grass is .ready to be cut a second
time when the dry meadows onlygive their first crop.
Thus by judicious management, three or four crops
of grass are obtained in‘ each season,‘ or only one
abundant crop is made into hay, and the sheep and
cattle feed off the others.” ‘The soil best adapted‘
for a water-meadow is a gravel or other porous soil
free from stagnant water, hence under-draining is
sometimes necessary, before the laying out of a good
meadow. When the beds are properly laid out and
rolled, grass seedisi sown, or the’ turf parings laid
down ‘again, or tufts“ of grass‘ from" old‘sv'vard are‘
spread over and soon cover the ground.w ‘ _
The herbage'produced in ‘England is some of the
best- in the world : ‘it’ is more variedjclose, and fine
than that of southern" countries, 'andmore' rich and’
vigorous "than that of northerly ,climate's-s It is watered
by‘ nun'ierousrivers, which’fl'ow th‘rough districts of
great ‘fertility, and-afford valuable nutriment, owing
to the quantity of animal and vegetable substances
with which they are enriched. Liquid manure is also
applied to the land in the same way, being distributed
and carried off like water. Muddy water is some-
times let into a field, and allowed to remain until it
has deposited its sediment, when it is let through
sluices. This is called warping, and is practised
where circumstances! will allow of it, at the mouths
of rivers, where the tides and the fresh water meet.
At the estuary of the Humber the water is carried
several miles inland, and will deposit in the course of
a single season more than a foot of rich soil. When
lands become gradually inundated through natural
causes, if the flooding does not continue ‘too long, it
may have a beneficial effect by the deposits left
behind; but when the inundation begins to subside,
it must be made to run ofi entirely, and not be left to
settle in pools, which would destroy the grass.
ISINGLASS. See GELATINE. v - k
ISOOHRONISM~ISOOHRONOUS, (from loos‘,
equal, and Xpdvos', time.) Vibrations or oscillations
performed in equal time are said to be isochronous.
It is a remarkable property of all systems which are .
in stable equilibrium, that when disturbed therefrom
by a greater or less impulse, the oscillations by which
they recover their original position are all performed
in the same time, or so nearly so, that any acceleration
or retardation is quite imperceptible. This valuable
property of isochronism' is taken advantage of in the
construction of instruments for measuring time. See
Honoroer.
A'renewed growth soon
ISOMERISM—ISOMORPHlSM—I VORY.
97
ISOMERISM, (from Zoos‘, equal, and pe’pos, jam-25,)
a term applied to that natural law by which certain
bodies may contain the same elements in the same
ratio, and yet possess distinct physical and chemical
properties. Isomeric bodies are of constant occurrence
in organic chemistry. For example, formic ether and
acetate of methyle are isomeric, both containing C6
H604 ; but as a difference in chemical properties is
fairly and properly attributed to a difference in 0012-
stz'z‘utz'on, if not always in composition, it has been
attempted to show that isomeric bodies vary in this
way. Thus formic ether may consist of formic acid
02H03 combined with ether C4HsO; and acetate of
methyle may consist of acetic acid C411303, and the
ether of wood spirit C2H30.
I$OMORPHISM, (from loos‘, equal, and polar/>1),
shape or form.) Certain substances of similar che-
mical constitution possess the remarkable property of
exactly replacing each other in crystallized compounds
without alteration of the characteristic geometrical
figure. Such bodies are said to be isomorphous. For
example, magnesia, oxide of zinc, oxide of copper,
protoxide of iron, and oxide of nickel are isomor-
phically allied. The salts formed by these substances
with the same acid and similar proportions of water
of crystallization, are identical in form, and when of
the same colour cannot be distinguished by the eye :
the sulphates of magnesia and zinc may be thus con-
founded. The sulphates, too, all combine with
sulphate of potash and sulphate of ammonia, giving
rise to double salts, whose figure is the same, but
quite different from that of the simple sulphates. In
the same manner alumina and peroxide of iron replace
each other without change of crystalline figure. The
alumina in common alum may be replaced by peroxide
of iron, the potash by ammonia or by soda, and the
figure of the crystal remain unchanged.
Mixtures of isomorphous salts cannot be separated
by crystallization, unless of very difl'erent degrees of
solubility. A mixed solution of protosulphate of
iron and sulphate of copper, isomorphous salts, yield
on evaporation crystals containing iron and copper.
But if, before evaporation, the protoxide of iron be
peroxidized, the crystals will be free from iron. The
peroxide salt of iron is not isomorphous with the
copper salt, and easily separates from it.
When compounds thus correspond, it is inferred
that the elements which compose them are also iso-
morphous. It is difficult, and often of course im-
possible, to ascertain the crystalline figure of most of
the elementary bodies, and the ditficulty is increased
by the fact that many of them are dimorpkous, ‘that
is, they exhibit two forms.1
IVORY. A beautiful and compact substance, ob-
tained from the tusks of the elephant, the narwhal,
the walrus, and the hippopotamus, and also from the
teeth of the same animals. The best and largest
supply is however from the elephant.
The male elephant when full grown has two tusks,
varying considerably in size in different animals, but
most valued when they are large, straight, and light
( I) Fownes’ Manual of Elementary Chemistry. 1850.
voL. IL
L
in colour. These tusks are hollow at their insertion
into the jaw, and for a considerable space therefrom,
but become solid as they taper towards the extremity.
The principal sources whence they are obtained are
the western coast of Africa and Hindostan ; but the
African tusks are most esteemed, as being denser in
texture, and less liable to turn yellow. By an analysis,
the African show a proportion of animal to earthy
matter, of 101 parts to 100 ; while in the Indian it
is 7 6 to 100.
The applications of ivory are so numerous that a
large demand for elephants’ tusks has existed for a
lengthened period. During twelve years at the close
of the last century, the imports into Great Britain
amounted on an average to 1,576 cwts. annually; in
183l and 1832 they had increased to £180 cwts., of
which 2,950 cwts. were retained for home consumption.
Now, reckoning the medium weight of a tusk at
about sixty pounds, it is evident that the imports of
the years last named would require ‘7,709 tusks, or
the destruction of 8,85% male elephants. But since
that period the imports have so greatly risen, that in
Sheffield alone 180 tons of ivory are worked up
annually into knife-handles, &c. It is also affirmed
that of the quantity of tusks imported, although
some weigh from 60 to 100 pounds, yet the number
of small tusks is so enormous, that an average weight
of nine pounds can only now be reckoned on; in
which case 415,000 tusks, from 22,000 elephants are
required to supply the demand of this great cutlery
mart of England. Occasionally, it is allowed, broken
or shed tusks are collected, or those of animals which
die a natural death are obtained; but the supply from
these sources is never very large, so that the slaughi
ter of elephants, after all deductions made, is going
on at a rate which leaves it a constant wonder
that the breed of this noble animal has not been
sensibly diminished. The value of the ivory con-
sumed in Sheffield is very great; but there are also
other seats of manufacture, and ivory is wrought
into the forms of chess-men, billiard-balls, the
of musical instruments, thin plates for miniatures,
mathematical and other instruments, and an immense
variety of small objects of use, amusement, or orna-
ment. None of our manufacturers have yet reached
the consummate skill of the Chinese in the work-
manship of ivory, chiefly remarkable in their con-
centric balls, their chess pieces and models. Yet
the adaptation to useful purposes of this valuable
substance is fully understood by those who cannot
rival the exquisite minuteness of Chinese art. A.
manufacturer of surgical instruments in Paris is in
the habit of rendering ivory flexible for use as tubes,
probes, 860., by acting on the well-known fact, that
when bones are subjected to the action of hydro-
chloric acid, the phosphate of lime, which forms one
of their component parts, is extracted, and thus bones
retain their original form, and acquire great flexibility.
M. Charriére, after giving the pieces of ivory their
required form and polish, steeps them in acid, either
pure or diluted, until they become supple and elastic,
and of a slightly yellow colour. In the course of
H
‘'1- “WA
15.5‘) D
98
IVORY.
drying the ivory returns to its original hardness, but
its flexibility can be easily restored by surrounding it
with wet linen, or by placing wet sponge in the
cavities of the pieces. In some cases, the articles
have been kept in the acidulated water, in afiexible
state, for a week, without change or injury, and
without acquiring any taste or disagreeable smell.
It has lately been ascertained that the decay of
articles in ivory can be efl’eetually checked, even
when its progress has advanced so far as to cause the
specimens to crumble away under the hands. Some
of the works in ivory forwarded by Mr. Layard from
Nineveh, were found on their arrival in England to
be in a state of rapid decomposition. Professor Owen
was consulted on the subject, and he suggested a
remedy which has proved entirely successful, thereby
preserving to this country these curious relics of an-
cient art. Concluding that the decay was owing to the
loss of gelatine in the ivory, he recommended that
the articles should be boiled in a solution of gelatine.
Under this process they became apparently as firm
and solid as when they were originally entombed.
The tusks of the hippopotamus aflord a very hard
and white ivory. These are usually short and much
curved, hollow at the place of insertion, and covered
with a glossy enamel. They vary in weight from three
or four pounds to thirty. These are highly prized by
the dentists, and are better adapted than any other
ivory for making artificial teeth. The thick coat of
enamel which covers them has first to be removed, for
this entirely resists steel tools, and under it is found
a pure white ivory, with a slight bluish cast. The
parts rejected by the dentists are used for small
carved and turned works. The horn or tooth of the
narwhal is also hard and susceptible of a fine polish.
The largest size is~ten feet long ; at the lower ex-
tremity it forms a slender cone of a twisted or spiral
figure.
Another and a very remarkable source of ivory is
that which supplies almost the whole of the ivory-
turner’s work made in Russia. Along the banks of
the larger rivers of the Russian Empire, and more
particularly those of further Siberia, thousands of
tusks are annually dug up, which once constituted
the weapons of defence of a species of elephant or
mammoth now extinct. These form what is called
fossil ivory, but they have not undergone the changes
usually understood in connexion with the term fossil,
for their substance is as well adapted for use as the
ivory procured from living species. So numerous
are these tusks, that they are occasionally exported
from Russia, being cheaper than recent ivory. They
are rarely to be met with in England, except in
museums. Mention is made, however, of one which
measured 10 feet in length, and was solid to within
6 inches of the root, weighing no less than 186 lbs. :
this was cut up into keys for piano-fortes.
There is a substitute for ivory now in general use,
which it is necessary to notice here. It is the fruit
of a species of palm, imported from Peru for some
time past into the European market, and named by
two Spanish botanists, who met with it in the groves

of Peru, P/zytelepfias maorocarjm. These writers also
supply the following description :—“ The Indians
employ the leaves of this most beautiful palm as a
covering to their cottages. The fruit at first contains
a clear insipid fluid, with which travellers quench
their thirst; this fluid afterwards becomes gradually
sweet and milky, and at length acquires solidity, so
as to be as hard as ivory. If the fruit be gathered
while the juice is fluid, the latter soon becomes acid;
but when allowed to attain perfection, the kernels
are of suflicient hardness to be employed by the
Indians as knobs for walking-sticks, reels of spindles,
and little toys, which are white, and perfectly hard
while dry; if they are put under water they soften,
but on drying, their hardness is restored. Bears
eagerly devour the young fruit.” Two species of
this palm are recognised, the P. macrocarpa, or large-
fruited, and P. microcmyaa, or small~fruited. The
vegetable ivory is in fact the albumen or nutritious
substance surrounding the embryo, and which in
some other palms, as the cocoa-nut palm, constitutes
a beautiful and firm substance lining the shell. The
vegetable ivory is enclosed in a hard rind, some of
which generally adheres to it as imported. The
Doum Pahn has a similar albumen, which is turned
into beads for rosaries.
The African ivory, as already stated, is superior to
any other: its appearance, when first cut, is mellow,
warm, and transparent, almost as if soaked in oil, and
with very little appearance of grain or fibre; the oil
dries considerably by exposure, and a permanent tint
then remains, a few shades darker than writing paper.
The Asiatic ivory is more dead-white at first, but is
more disposed of the two to turn yellow afterwards.
It is also less dense, and does not take so high a polish.
The choice of ivory is accompanied with much 1111061”!
tainty, even to experienced buyers. The tusks are
received in all varieties of size and figure. They
may be 8 or 10 feet long, or only as many inches.
They may weigh (as we learn from the magnificent
specimens in the Great Exhibition), 325 lbs. the
pair, or they may not reach as many ounces. Mr.
Holtzapffel mentions a small and hollow tusk in his
possession, which only weighs 2% ounces. Their
curvature may describe a simple half circle, or they
may be curved in two directions, the tusk inclining
to the shape of the letter S. The outside may be
dark-coloured almost to blackness, or it may run
through all the varieties of light and deep orange,
hazel, and brown; their ends may taper off to a fine
point, or they may be very much worn away, or they
may end abruptly as if broken ofl.
The buyer, therefore, has to make the best selection
he can by choosing a tusk as nearly straight, solid,
and round as possible, with a smooth rind free from
cracks, and a point that gives evidence in the worn
part, that the tusk is of the desired fineness of grain.
Yet’after all precautions, it is only after the first cut
of the saw that the quality can be really determined.
Sometimes the interior exhibits a succession of layers
or rings, of different shades and degrees of transpa-
rency ; sometimes the solid parts of the most beauti-
IVORY.
99
ful and transparent tusks have long oval patches of
opaque white ivory, in some cases a regular grain is
observable, almost like the engine-turning of a watch—
case 5 in others no grain is perceptible 5 occasionally
there is a deficiency of animal oil, and the ivory crumbles
under the workman’s tool; or there may be the serious
defects of darkness of colour, and coarseness of grain.
In rare instances a considerable portion of the tusk
is found to have been injured by a musket ball, the
iron or leaden bullet being enclosed in it. Two
instances, if not more, have occurred in which these
bullets were of gold, showing that the shot was fired
by royal hands, for it is the reputed custom among
Eastern potentates to use gold or silver bullets in
their sports. One of these golden bullets is stated
to have been cut through by a comb-maker in dividing
a tusk. The portion of the tusk thus injured, is
generally useless for any ornamental purpose for
many inches each way around the ball; but cases
have occurred in which a ball, and even a spear-head,
has entered at the thin part near the skull of the
animal, and become embedded without injury to the
external surface.
Great economy is used in cutting up the tusks, so
that the only waste may be that which arises from
the passage of a thin saw between the several pieces
into which it is divided 3 and even here it can hardly
be termed waste, for the clean saw-dust of the ivory
is sometimes used in making jelly. Every portion is,
in fact, turned to some account, the outside rind
being used for handles of pen-knives, &c., and the
scraps burned in retorts for the manufacture of ivory
black, used in copper-plate printers’ ink, and for
other purposes. The saw used in cutting up the
ivory is about the fortieth of an inch thick, with
rather coarse teeth, about five or six to the inch: it
is stretched in a steel frame to keep it very tense.
The sawing is commenced at the root end, and two
or three pieces are cut to the lengths of such articles
as can be made in that thinner portion of the tusk.
The blocks are rarely cut more than five or six inches
long. As the solid part of the tusk is reached, the
blocks have to be greatly subdivided; perhaps longi-
tudinal slices have to be cut for miniatures, or the
taper handles of knives and razors have to be
economically severed by cutting the slabs wedge
form, the thick end of one against the thin end of the
next, and then subdividing by parallel or inclined
cuts, made either with the saw just described, or
with the circular saw. The entire division of each
block or length of tusk is settled and accurately
marked in pencil upon the end of the piece, before
the saw is used. When the tusk is to be used for
turnery work only, the first cut is usually made where
the hollow ends, which is ascertained by thrusting a
wire up the tusk. Unless the latter is extremely
curved, the principal part is formed into cylinders
or rings, but the greater the curve the shorter
the pieces that can be prepared from it with-
out waste. The mode of centering the pieces, or
placing them in the lathe, is thus described by M r.
Holtzapfiel :--“ The first process in preparing to

rough-turn the block, is to fix it slenderlyin the lathe
between the prong-chuck and the point of the popit-
head, and its position is progressively altered by
trifling blows upon either end, until when it revolves
slowly, and the common rest or support for the tool
is applied against the most ‘I g "1’
prominent parts, a, e, and 0
respectively, the vacancies or 0'
spaces opposite to each at d, (I ‘
Z2, and f shall be tolerably Fig-1257-
equal, so that, in fact, about a similar quantitymayhave
to be turned away from the parts a, e, and c, for the
production of the cylinder represented by the dotted
lines within the figure.
The centres having been thus found, they should
be made a little deeper with a small drill, and then
the one end of the block being fixed upon the prong-
chuck, the opposite extremity, supported by the
centre, is turned for a short distance slightly conical,
ready for fixing in a plain boxwood-chuek, or a brass
chuck lined with wood to complete the rough prepa-
ration, unless, indeed, it is entirely performed upon
the prong-chuck. With the decrease in length less
attention is requisite in the centering, on account of
the interference of the curvature of the tooth, and
the pieces may at once be rasped to the circular form,
and then chucked, either in a hollow chuck, or else
by cement or glue, against a plain flat surface.” It
is recommended, however, that the amateur become
familiar with the various methods of chucking on less
costly materials before he largely employs ivory.
Pieces of ivory in which there is a small hollow in the
centre, are temporarily rendered solid by rasping a
piece of beech wood, and driving it in; the work can
then be centred as just explained with the hollow
pieces, the process of turning is repeated on the
inside, a side cutting tool, with a long handle for
a secure grasp,
being used, and
the tool held
very firmly, for
which purpose
the sliding rest
is very desirable.
When thin rings
or short tubes of Fiy- 1258-
ivory are required, they are frequently cut one out
of the other in the lathe with the parting tool, as
in Fig. 1258.
Works intended strictly to match each other
require to be cut from the same tusk, where this is
possible, it being almost impossible to match works
from different tusks in colour, transparency, and fibre.
Works in ivory, too suddenly exposed to heat and
dryness, are apt to split: on this account they should
never be placed on hot chimney-pieces, or under the
direct rays of the sun. Ivory resembles wood in the
changes it is liable to from warping and splitting.
There are some woods, indeed, less liable to vary than
ivory, such as box-wood and lance-wood. In the
recent Parliament Survey, drawing scales made of
these woods were sanctioned by the Tithe Commis—




n 2
100
JADE—JAL AP-JAPANNING.
sioners, as being next in accuracy to metal, while
ivory scales were quite rejected, owing to their varia-
tion in length under hygrometrical influence. The
change in the length of ivory articles does not, how-
ever, equal that of their width; thus billiard balls
are apt to become different in their two diameters:
the best are made out of tusks scarcely larger than
themselves. There are various recipes for bleaching
ivory when it has become discoloured, but they ap_
pear to be of very little value.
IVORY-BLACK. See CARBON, vol. i. p. 315.
J AGQUARD APPARATUS. See WEA'VING.
JADE. This name has been given to serpentine,
nephrite, and saussurite, but is usually applied to
nephrite, a massive, tough, translucent mineral, com-
posed chiefly of silica and magnesia, with or without
alumina, oxide of iron, and lime, but varying in
constitution. In New Zealand and China it is
valued for its supposed medical properties, and is
carved into images, and polished down into amulets
and various fanciful shapes. Some of the mineral
from China called Yu, or Jade, is however, supposed
to be prehnite. Jade is polished by lapidaries like
carnelian, but only takes a greasy, and not a brilliant
polish.
J ALAP. A common and useful medicine, obtained
from the roots of a species of Gonvolvulus (0. Jalapa)
chiefly obtained from Vera Cruz, and named after the
town of Xalapa or J alapa in the interior. The roots
are collected in March or April, before their resinous
juices are weakened by the development of the
young shoots: some of them are of great size, weigh-
ing as much as 50lbs. They are divided into portions,
and hung in nets over a fire to dry. In commerce,
jalap is often adulterated with roots of white briony,
which are white or grey, spongy and not resinous,
whereas genuine alap is hard, resinous, with a brown
shining fracture. 100 parts of the dry root have
been found to yield ten parts resin, forty-four parts
gummy extract, twenty parts woody fibre, and twenty
nine parts starch, albumen, salts of lime, potash, &c.
J APANNING. A method of varnishing articles
in wood, metal, and other substances, originally
practised by the natives of Japan, with a peculiar
lacker obtained by making incisions in the lower part
of the trunk of a tree, the growth of their islands, and
collecting the juice. This juice is at first like cream,
but becomes black by exposure to the air : it hardens
better than any other lacker, and is sometimes brought
over to this country, but is not generally used. The
Japanese method of employing this lacker is said to
be as follows z—After exposing it to the air for many
hours, until it becomes of a deep black, and adding a
fine powder consisting of charred wood, they then
spread the lacker thinly and evenly over the article,
and dry it in the sun. Another coat is then laid on,
and dried as before. It is soon extremely hard, and
will bear polishing with a smooth stone and water,
until it becomes as even as a plate of glass: it is
then wiped dry, and the forms of figures and other
prnaments are traced with a pencil dipped in varnish
made of boiled oil and turpentine. Before ‘this

varnish-tracing is quite dry, gold or silver leaf is laid
on, and the whole then receives a finishing coat of
the varnish.
Our method of japanning differs from this in certain
particulars. For black japanned works, the ground
is first prepared with a coating of black, consisting of
drop ivory-black mixed with dark-coloured anime
varnish. This coating is well dried in a stove, and
then varnished three or four times, the work being
well dried between each. If coloured grounds are
required, one or two thick coats of colour mixed with
varnish are first laid on, and. several varnishings and
dryings complete the work. The ordinary painter’s
colours, ground with linseed oil or turpentine, and
mixed with anime varnish, enable the workers in
japan goods to produce a variety of effects according
to their taste and fancy. The articles may be black
or brown with gilded edges, or they may imitate
marble, fine-grained wood or tortoiseshell, the last
named being produced by vermilion with a varnish
of linseed oil and umber. The colours most in request
for this kind of work are flake-white or white-lead,
Prussian-blue, Vermilion, Indian-red, king’s—yellow,
verdigris, and lamp-black, with numerous intermediate
tints produced by their mixtures. The varnishes
employed are copal, or avarnish composed of seed-lac,
or of gums anime and mastic. The lac varnish is the
best as it respects hardness, but is too high coloured
to be used alone on the more delicate grounds : it is
therefore mixed, for such purposes, with gum-varnish,
or it is superseded by copal varnish. Copal or anime
varnish made without driers is applied two or three
times, or as many as five or six times to the best
works, to protect and give brilliancy to the colours.
It frequently happens that the articles to be
japaimed are either too coarse and soft to receive the
lacker, or their substance is not sufficiently smooth
without priming and preparation. Perhaps every
workman has his own favourite method of preparation,
and of mixing his varnishes ; but it must be remarked,
that whatever the care employed, works executed on
an artificially prepared ground can never be depended
on for durability, being much more liable to crack
than those which are lackered on the solid substance
of the object itself. The priming is of size and
chalk or whiting, mixed up to a proper consistence
to be laid on with a brush. It should be left a day
or two to dry, and then brought to a proper smooth—
ness of surface by rubbing with rushes, and then by
the application of a wet cloth. When thoroughly
dry the grounds are laid on smoothly with a brush,
and finished by varnishing and polishing with rotten
stone, or if the ground be white with putty or starch
and oil. A brilliant ground is sometimes formed by
laying it entirely in gold. This is done by going
over the work with japanner’s gold size, and when
this is nearly dry but still clammy, it is covered with
gold dust, applied on a piece of wash-leather. This
when highly varnished has a very splendid effect.
Ladies’ work-boxes, work-tables, &c., are frequently
ornamented with engravings or drawings transferred
to the japan work. For this purpose the engraving
‘ J ASPER—J ET--J EWELLING OF WATCHES.
101
is printed, or the drawing made on fine paper which
has been previously prepared with a coat of isinglass
or gum water. This, when dry, is applied with its
face downwards upon the japan ground, covered with
a thin coat of copal varnish; the paper is then
moistened on the back with a sponge dipped in warm
water, which soon dissolves the isinglass or gum,
and the paper being loosened can then be taken
away, leaving the print on the work. Or a print
may be executed on an elastic composition of glue, 82.0.,
which‘ receives the impression as well as paper, and
may be immediately laid down upon the japanned
surface, which will thus receive a perfect impression.
All the processes connected with japanning require
so much drying between them, that it is very desir~
able to hasten the work by means of stoves.
Common articles of furniture, such as dressing-
tables,-chairs, washstands, &c. are frequently said to
be japanned, implying a greater durability than ordi-
nary wood-painting; but the chief difference seems
to be that the colours employed in painting them
have been mixed with turpentine instead of oil.
JASPER. A handsome stone for inlaid work,
which admits of a high polish, but is not used as a gem.
It is a siliceous rock, containing, according to Beudant,
silica 93-57 per cent., peroxide of iron 3'98, alumina
0'31, lime 1'05, water 1'09. It is coloured red by
the peroxide, and yellow or brown by the hydrate of
iron. It also occurs of green and other shades. When
striped with green, yellow, red, or brown, it is called
ribandjasper. When these colours are in irregular
concentric zones, it is called Egypz‘z'anjasper. Another
variety is called ruin jasper, when a variety of brown
markings appear on a dark ground. Jasper is nearly
equal to agate in point of hardness, and is subject to
the same treatment as carnelian in the lapidary’s art.
JET. A variety of bituminous mineral coal, harder
than cannel coal, of a deeper black colour, and possess-
ing a higher lustre. It receives a brilliant polish, and is
worked in the same manner as alabaster. In jewellery,
the use of jet in mourning ornaments is very cen~
siderable. Jet is found at Whitby, Scarborough, and
Yarmouth, and is also imported from Turkey. It can
be turned with most of the ordinary tools, and worked
with files and saws. Before the polishing, it appears
of a brown colour, but after that process, it attains a
beautiful and brilliant black. See COAL.
JET D’EAU. See An'rnsrxn Srnnves.
JEWELLING OF WATCHES. The frame-plates
and other parts of watches are perforated by the watch-
finisher, or escapement-maker, for the watch-jeweller,
whose business it is to fit into the holes thus made
certain hard stones, such as rubies, sapphires, chryso-
lites, and in some cases, diamonds, so perforated that
the pivots of the watch movement may work in them.
Diamonds are chiefly prepared in Holland, but all
other hard stones are ground, polished, turned, drilled,
and set by the watch-jeweller. Diamond powder
(bort), embedded in small copper disks or mills, is the
material used for grinding and polishing; and a frag-
ment of bort set in a handle (as explained under
CARBON, where different forms of diamond tools are

figured,)'is used for turning and drilling. A steel
tool with diamond powder and oil is also used for
drilling. Rapid motion is given by a lathe, with a
large foot-wheel, so as to give the mandril from 6,000
or 7,000 up to 20,000 revolutions per minute, the
latter speed being given for polishing only. The
stone is ground by taking it on the end of one of the
fingers of the right hand, and applying it to the surface
of the bort mill, which is kept constantly wet with
water applied by the fingers of the left hand: in a
few seconds a flat surface is produced on a stone of
the most irregular form; the flat surface is then
placed next the finger, and a similar surface is pro-
duced parallel to the former, until the stone is of the
thickness required: it is then placed, by means of
cement, on a small chuck in the lathe, and turned
with a bort tool into the proper shape for setting:
the hole is then drilled, first, about half way through,
when the stone is reversed, and the drilling completed
from the opposite side; a precaution necessary .to
prevent ‘fracture. The hole is also turned with a
countersink, to receive the oil required for the lubri-'
cation of the pivot. The polishing is performed by
hollowing out one end of a piece of brass, so as to fit
the hollow of the stone, and with diamond powder
therein, working it about in every possible direction,
by pressing the finger against the other end of the
brass. The stone is then detached from the lathe,
and its flat surfaces polished by the rapid motion of
the hand on a piece of plate-glass charged with dia—
mond powder and oil.
Stones may be perforated so that the shoulder of
the axis be supported by them; or in such a way,
that the axis may pass completely through them, in
which case an end-piece is required for supporting the
end of the pivot. The latter method is adopted
where the pivot is in rapid motion, and has a con-
siderable weight to sustain, as in the case of the
pivots at each end of the axis of the balance.
Fig. 1259 is a section, on an enlarged scale, of the
jewelled pivot-hole for the axis of the balance of a
chronometer. a is the hardened steel pivot, which is
turned with a fine cylindrical neck, and made convex
at the end. 6 is the drilled jewel, and above it, the


Fig. 1259.
end-piece. b is turned convex above, and concave
beneath, of two different sweeps, to make it very thin
at the point where it is drilled, and it is made a little
smaller in the middle, to lessen the surface bearing.
The end-stone is in the form of a Plano-convex lens :
it is generally a ruby, but in some cases, a diamond,
cut into facets. The very small distance between the
two stones allows the oil to be retained by capillary
attraction. Each stone is burnished into a brass or
I02
Kanrssnnnivrnss-Kmnsi-Krnrci AGID—KINO.
steel ring, in a manner‘ similar-'to-tliats-iu which
glasses are set in telescopes, -' by turninginaplace to‘
receive the stone, and ‘leaving-a fine vedge of brass;
which is ‘ rubbed- .ov'er 7- the ‘edge ' ef~~ the stone‘ withra‘
burnisher. A. ‘diai'non'd end-piece ‘is usually‘ ‘set in
steel, intow'vhi'ch‘lit is: brazed‘; after whiehythesteel
is turned‘: intovishape,“polished; '‘ and; - bleed. The”-
stones are iinlaid» in jaifcouuter sunk 'r'ecess',-T-a 21,‘ in ‘the
side plate, -' or ‘other part ~ ‘of-the.- watch; and retained
therein by-‘twor-side-serews,vas‘ [shelwngi’n the figure.
_ The- .jewellingl'of- watches-“is g=‘verlyn'iinut'e-'and~ deli-1 1
cate workglasl'will 'Yb’e' understood fromftlie statement
of" the? dimensionsiof-1 the *Iparteof Fig.1259: the
side platee ais inch = in; thickness ‘:r' the‘ rings. from
cPto ‘cl geinch in diameter, and-the- pivot inch in
diameterx ’ In.‘ s0n1e‘1’0f9theflat Geneva watches,
these dimensions 1 are greatly - reduced.-
.- 'JOINERY.” SEGCARPENTRY.’
IJO-ISTS. See‘ 'OARPENCBRY.
JOURNALS". See- Guncnons.
KALI. The name: of ‘ a maritime plant, vthe ashes
‘of which furnishsoda.‘ From the name of‘ithis plant,-
with the Arabic article a1, is ‘derived the name of a
class of substances‘ of great. importance in vthe arts.
[See ALKALL] . The term 'kali'was formerly applied to
the alkali potashgth'echemical symbolfof which, K, is
the initial letter _of ‘kalium-z‘; ' ,- 5 1 i D
KAOLIN. See» (53min, also: 'Iri'rnonucronr Essay,
p.1xxxiv. r~ :5! 7' -~ ' ‘r: ' " A
KEL'P. 1The as remaining after burning-‘seaweed,
for the purpose of obtaining carbonate of‘ soda from
it.‘ See SODIUM, IT'onrnn. ' ‘I '- ' ’
. >KERMES. Two‘ substances of totally different
properties ‘are known by this name; the one, kermes
mineral,‘ is; the golden 1 ~ sulphuret of antimony, [see
An'rrMoNm] the otlreigsrlceriizes‘grains, 'a-redv i‘d‘ye- stuff,
eonsistingiof the dried‘ bodies _of the female insects; of
the~ species cocciis ilicis, and found upon the leaves ‘of
the guerczis iiex, or prickly oak.- The word- kermes,
signifies in Arabic little-worm; "hence, this dye was
called uei'miciilus in Latin, and‘ 'iiei'miiioiz in French,
a term now applied to the red vsulphuretof mercury.
Kermes was f0rmerly~~kn0wn ‘as German cockiizeal.
The rural- serfs of- Gcrmanywere boundlto deliver
every year to the convents, a certain quantity of
kermes: it was collected from the trees upon St.
John’s ;day, between‘. _ and-noon,’ iwith ‘cert ain
religious ceremonies,‘ai'idiwasplionce»fealledJokaiinis-
Mai, or St. Johni-s blood; ~ discovery of
America, cochineal gradually supersededmkermes for
all brilliant red dyes. Lac dye is also an advanta
geous substitute; but at V_ the present day, the Turks,
Armenians, and Cossacks ‘dye with kermes their
morocco leatheryeloth," silk, -ho'rise: hair, 850. ‘The red
caps ef-theL Ii'evantware dyed with. equal apartskermes.
and -fmadde'r'.n aScarilet. and? crimson dyed with vkermes.
were called grain-colours, and were» supposed'to bev
more durable 'than 1 eo'chineal. eolours,=ras - the old
Brussels tapestry may éshowa-i , " ' . ~ . '
The colouring matter. ofker'mes is soluble in water
andsalcoholé it-becomes yellowish- er-v brownish withj
aeicls',_and-violet or “crimson with ‘alkali's. Sulphate.

'1 of iron 'blackens it; it dyes a blood red with alum;
fan“ agate grey with copperas; with copperas and
@tartar‘a lively grey; with sulphate of copper and
{tar-tuna‘ lively green; with tartar and salt of tin, a
lively cinnamon yellow’; with a larger proportion of
@ ailum- ' and <tai-_tar,»- ~a= lilac‘;
tartar, a violet?
with sulphate of zinc and
> Kerm'e's should be plump, of a. deep red colour, with
‘ an agreeable smell;- and a rough pungent taste.
' ~ KERSEYMERE» "See WOOL.
' ‘Kl'L‘LAS-"Sec Introductory-Essay, p.1xxxviii. note.
1 KlLNé, a name applied to various-‘form's of close
furnaces, differently arranged according to the pur-
poses ‘foriwhichwthey are intended.‘ "Different kilns
are described under BRI‘CK,'= LIMESTONE, Po'rtrnnr,
&c. A malt liiliz is described‘ under Bnnn ;' and it
has beenv supposed that-‘the operation of killing or
quelling the vegetation of thefrmoistcned barley by
heat, has ‘given ‘the name of lcili or kiln to the hot
chamber in which it was performed, and hence also to
other enclosed heated places. '
KING’S- YELLOW, a» pigment, the basis of which
is‘ orpiment' or yellowr'sulphuret of arsenic (As S3).
See Ansnnre.
KINIO AGID, an acid contained in the different
species of cinch'ona or Peruvian barks, in combination.
with lime. It isv also named Paine/ionic or giiiiiic'
acid.» Kinate of lime is found inv the solution from
which the bark alkali-‘s ‘have been ‘separated, and‘ the
1acid is' ‘extracted by decomposing the l-limessalt by
dilute sulphuric acid? The clear solution, on being-
evaporated, deposits‘ large- distinet' crystals of kinic
acid, which resemble those of tartaric acid. Kinic
acid is soluble in 2 parts water, ‘and contains
6141111011, 110- r
- When lkinici acid is treated with sulphuric acid and
peroxide‘ of manganese, it furnishes a very volatile sub-
stance, terme'd ciiiizoize, the vapour of which is very-
,irritating to‘ the eyes=.~ ‘It ‘contains Cgfi'Hs-OS. The
iodour of'chinone is ‘so distinct, that it enables us to
detect the presence of kiuic acid, and thus serves as a
‘means of ‘distinguishing ‘true from spurious barks.
According‘ to- Stenhouse, “to examine a bark for
gkinie‘ acid,‘all" that 'is'necessa'ry is to boil a little of it
i with slight excess‘ of lime, to pour off’ and ‘concentrate
{the ' liquor, introduce it into a retort, and distil ilt
jwith a mixture‘ of half its weight of 'sulphuric acid-,-
and of peroxide of ‘manganese. f If the contain
the smallest quantity ofkiniet acid, the first-portion
,of the liquor which vAdistilsv"foi'rerihas a yellowcolour,‘v
and the ‘very peculiar serene-of’ chinene-f-t ‘ ‘Less than
I 2% ounce ‘of bark isr*%s’ufiieient1ferf the experiment : - the
1 distillation ‘need ‘notib’etcontinued long,- on. account of.
‘the 'gi'eatvolatilit'y efritheaehinene. ‘a Two ' ounces‘ of
false i'baIikIt'G/ltititl iiio’uii’@Siiriiiammsis), treated in this
7 way, "gave 1‘ no- ’indiea'tioiis' ofiikinjicf, acid.1
‘I KINQ'an‘extraCtivcQmatter, the concrete juice of -
one' or ‘more plants growing-
the East and-West
Indies, Africa-1,‘ New-‘Holland, ‘as. "n is of a reddish
chiefly of - tannins. > -
‘ U) i‘Memoirs of'tiié-Chemieal Society,” v01. in.
brown colour, ‘has a bitter styptic taste, and consists‘

Kenmore-rare.
103
KNIVES; See CUTLER-Y. " i' “
KREOSOTE, (from xpe'as, flesh, and o‘oiféa, I pre-
serve.) This interesting product is obtained by
distilling wood tar. It is remarkable for its anti-
septic power. A piece of 'flesh steeped in a very
dilute solution, dries up, but 'does not putrefy. The
great efficacy of impure wood vinegar in preserving
provisions, is due to the kreosote contained in it, and
the effect of wood-smoke in curing and preserving
salted meat and other provisions, is due to the same
‘cause.
Kreosote - exists abundantly in the heavy oil of
beech-tar, as supplied by the wood-vinegar maker,
and is procured therefrom by a tedious series of ope-
rations, which are described by Dumas in the 5th vol.
of his “Ohimie appliquée, etc.” The distillation is
conducted in a metallic‘ vessel, and the different
products collected apart. The most volatile portion,
which is lighter than water, is rejected, but the
second and denser portion, containing the kreosote,
is agitated with carbonate of potash, to remove
any adhering acid. This denser portion is then se-
parated, and redistilled. The first portion that comes
over is again rejected. It is then briskly agitated
with a solution of phosphoric acid, and again
distilled, whereby ammonia is separated. It is next
dissolved in a solution of caustic potash of specific
gravity 1'12, and decanted from the insoluble oil
which floats on the surface. This alkaline liquid
is boiled, and left some time in contact with the air,
by which it acquires a_ brown colour. Sulphuric acid
is next added to separate the alkali. The kreosote is
again dissolved in caustic potash, boiled in the air,
and the solution decomposed by acid, and this treatment
is repeated until the product ceases to be coloured
by exposure to air, and to the alkali. Much of the
kreosote of commerce, however, turns brown by
exposure, showing that it is not quite pure. It is,
lastly, well washed with water, and distilled from a
little hydrate of potash. The first portion that
comes over contains water: the after product is pure
kreosote. In this condition it is a colourless, some-
what viscid oily liquid, of great refractive and disper-
sive power. It has a penetrating peculiar odour,
resembling that of smoked meat. It is most painfully
pungent when applied to the tongue in small
quantities. Its density is 1037 ;> its boiling point
897° Fahr. According to Ettling, it consists of
7742 carbon, 8'12 hydrogen, and 14416 oxygen, but
its exact composition cannot be said to be settled.
It is not readily ignited, and it burns with a smoky
light. When mixed with cold water two solutions
result, one consisting of 1'25 kreosote + 100 water;
the other'of 100 kreosote + 10 water. The aqueous
solution is neither acid nor alkaline. Hot water
dissolves a: little more kreosote than cold, but the
excess is again liberated on cooling. Kreosote
absorbs moisture from the air. It dissolves readily
in acetic acid: alcohol and ether mix with it in
all proportions. Caustic potash dissolves in it,
forming a crystalline'pearly compound. It dissolves
the resins, camphor, the essential oils, and most.

colouring’ matters. J It' immediately coagulate‘s egg
albumen, althou h much diluted. ‘ I;
Mr. Fitch has patented a process for’impregnatiug
salt with the more volatile products of wood-tar.
The salt thus‘ prepared is doubly preservative, and
meat to which it is applied, is at once smoked and
salted. > Tongues‘ and hams may be effectually cured
by immersing them for 241 hours in a mixture of 1 part
pure kreosote, and 100 parts of water or brine: the
resulting flavour is said to be very delicate. Kreosote
is medicinally employed ' in toothache, for dressing
ulcers, and for external application in cutaneous
diseases. It is also used to check haemorrhage, and
internally as a stimulant, and for the prevention of
nausea and vomiting. It also prevents mouldiness
in ink. -
LAG,’ a resinous substance found on several
difiierent kinds of ‘trees in the East Indies, and pro‘-
duced by the punctures of-an insect (6000268 Zacca),
aiid by its‘ formation of the exuding juice into cells
for its eggs, These adhere to the branches in grains,
completely encrusting them, and are either imported
in that form, and called stick-lac, or the grains are
gathered from the branches, their colouring matter
extracted, and formed into flat cakes, still preserving
the granular/appearance, and called seed-lac, or the
seed-lac is melted‘ up into masses, and called law/10-
Zac. Finally there is shell-lac, which is seed—lac
further purified by being put in bags of fine linen,
and melted over a; charcoal fire until it passes through
them; The bags are squeezed, and passed over a
smooth surface of wood, on which the lac is deposited
in thin layers. If ' pure this-kind of lac will take fire
on a'h'ot iron, and burn with a powerful smell. The
heat of a ship’s hold will sometimes run it, into a
solid mass, and thus diminish its value. The chief
consumption of lac in Europe is for the manufacture
of sealing-wax and varnishes. In India the inferior
kind is made ‘into bangles or armlets for women of
the lower classes, the superior is fashioned into rings,
beads, and other trinkets; and to fit it for such pur-
poses, the natives purify it by melting in the manner
above described. When the lac begins to exude, it
is scraped off, and the bags are twisted or wrung by
means of cross~sticks at their ends, to force out the
melted contents.
The Indians make a good varnish of lac, coloured
with cinnabar or some other pigment, with which
they varnish boxes, cabinets, and other articles.
Coloured varnishes of this description are much used
in the adornment of their religious houses. They
also employ lac as a dye. By pouring warm water on
stick-lac a crimson colouring matter is obtained,
which is made into square cakes for sale, and called
lac dye, lac lake, or cake Zaire. These cakes when
broken are dark—coloured, shining, and compact, but
when scraped they yield a bright red powder ap-
proaching carmine. A mixture of lac, alum, and
tamarind-water is the native dye for silk or cotton
cloth of a crimson colour. The Indian lapidaries
make use of lac as a vehicle for retaining the
hard powders used in cutting and polishing gems.
(
10a
meg-Lacuna;
The Indian corundum wheels are described under-
EMERY.
The dye above referred to, and which constitutes
much of the value of lac, is due to the insect which
makes the cells, and which is of the same family as
the cochineal insect. The parent lac insect, after
laying her eggs, becomes a mere lifeless bag, of an
oval shape, containing a small quantity of a beautiful
red liquid. The young insects feed on this liquid,
and their bodies assume the same hue, so that the
branch which bears them appears to be covered with
red powder. The cells of gum-lac which shelter them
are more or less deeply tinged with the same colour.
The best time for gathering stick-lac, so as to secure
the colouring matter, is before the insects have made
their escape. ‘ .
Previous to the discovery of the true cochineal, the
colouring matter of the lac insect was universally
employed for dyeing red. The
crimsons of Greece and Rome,
and the imperishable reds of the
Brussels and Flemish schools,
were obtained from this source.
The best quality of stick-lac
is obtained from Siam; the
twigs being fre-
quently. encrust-
ed all round to _
the depth of a ‘
quarter of an inch ,
while sometimes
-___=_==a .-'
m. —H‘—._-: '
:gqn: .
M >'~ : » a”.
- ' a, "a
w
a great accumula~
tion takes place .1, on one spot, as
shown in Fig.
1261: that of
A s s am rank s
next: the stick-
lac of Bengal is
inferior to these, being scanty and irregular in its
coating of resinous matten- So abundant is the
supply of lac among the uncultivated mountains of
India, that it is asserted a consumption ten times
greater than the present might be readily supplied,
The accumulation of insects is so great, that the
trees, often a species of ,ficus, on which they live,
are exhausted and injured by this vermin.
After the dye is extracted, the gum-lac still requires
much purification before it can be used for the more
delicate varnishes. It was long a desideratum to
render lac colourless, its dark brown hue being a
drawback to its use as a spirit varnish. A premium
of thirty guineas and a gold medal were offered by the
Society of Arts for “a varnish made from shell or
seed lac, equally hard, and as fit for use in the arts ”
as that prepared from any other substance. These
were claimed by two persons, Mr. Field and Mr.
Luning; and as both their processes were found to
answer the desired end, a premium of twenty guineas
was awarded to each. See Vannrsnns.
LACE.’ See WEAVING.
A LACKER, ‘or LACQUER, a varnish either for wood

Fig. 1260. Fig. 126].

or for brass, made with shell—lac and spirits of wine.
That for wood, called hardwood lacker, may be in the
proportion of 2 lbs. of lac to the gallon. Another. recipe
is 1 lb. of seed-lac and 1 lb. of white rosin to a gallon
of spirits of wine. For brass the proportions are
it; lb. of pale shell-lac to 1 gallon of spirit. It should
be made without heat, but simply by agitation for
five or six hours. It should then be left until the
thicker portions have subsided, when the clear lacker
must be poured off, or if not sufficiently clear, it must
be filtered through paper. ‘It darkens by exposure
to light, so that paper should be pasted round the
bottle to exclude it. i A pale yellow lacker may be
prepared from 1 oz. of gamboge and 2 oz. of Cape
aloes, powdered and mixed with 1 lb. of shell-lac.
For a full yellow, 1,; lb. turmeric and 2 oz. of Igamboge;
for a red lacker, % lb. of dragon’s-blood and 1 lb. of
annotto. The colour, however, is modified by that of
the lac employed. Lackers may also be coloured by
dissolving the colouring matters in spirits of wine,
and adding the proper proportions of these to the
pale lacker according to the tint required. Mr. A. Boss
prepares lacker with 4: oz. of shell-lac and 1.} oz. of
gamboge, dissolved by agitation in 24 ounces of pyro-
acetic ether. The clear liquor is decanted, and when
required for use is mixed with eight times its volume
of spirits of wine.
Hardwood .laeker is applied nearly in the same
manner as FRENCH POLISH. In lackering brass, the
work must be cleansed from grease and oil, and if
convenient, heated to the temperature of boiling water,
when the spirit evaporates, and the varnish attaches
itself more firmly to the metal, producing a brilliant
effect. If heat cannot be applied, the air should be
dry and warm. The lackering should follow imme-
diately after the work is polished, otherwise it will
become tarnished, and prevent the lacker from adher-
ing. To prevent this tarnish, the work may be
smeared over with oil, or kept under the surface of
pure water, or wrapped closely up in cloths. Before
lackering, the oil must be carefully cleaned off with
moslz'rzgsf and afterwards with whitening applied with
a rag or a brush. In brasswork factories, a lac/raring-
stove, with a broad, flat top, is used for holding the
articles which are to be heated preparatory to lacker~
ing ; or a metal plate, supported by four legs like a
table, and heated by a ring of gas-jets below, may be
used. Brass tubes may be heated for lackering by
being filled with boiling water, the ends being stopped
with corks. In lackering the heads of a large number
of small screws, they may be inserted in a piece of
card, and heated over a charcoal fire or a gas flame,
and the whole be lackered at one process. In thin
circular works, the friction of polishing gives the heat
required for the process. The lacker must be laid on
quickly and uniformly by means of a camel’s-hair
brush; and as soon as one coat is applied, another
must be put on, heat being used between the two
coats if necessary. Circular works may be lackered

(I) The thin shreds or shavings of leather, shaved ofi’ by the
currier in dressing cow or calf skins. They are as bibulous as
blotting~paper, and well adapted to remove grease.
LAGTIG AGID—LAGTQMETER—LAMP.
105
in the lathe. After the lacker ‘is applied polishing
completes the process.
LAOTIG ACID. When azotized albuminous sub-
stances begin to decay, they possess the property of
inducing an acid fermentation in sugar, whereby it is
converted into lactic acid. The azotized matter of
malt, the gluten of grain, wheat flour made into a
paste with water, if left for a few days in a warm
situation, become converted into lactic acid ferments.
In a more advanced stage of putrefactive change,
these substances act as alcohol-ferments or common
yeast.
This acid was originally discovered in sour mz'Z/r,
whence the name. It may also be extracted from a
variety of. liquids containing decomposing organic
matter, such as sauerkraut, the sour liquor of the
starch-maker, &c. It consists of 06H505+ HO; the
water being basic, and capable of being replaced by a
metallic oxide. The salts of this acid are termed
Zacmtes.
LACTOMETER, a kind of hydrometer for ascer-
taining the value of milk by noting its specific gravity ;
but as cream is lighter than ‘milk, milk rich in cream
and milk largely adulterated with water might furnish
similar results, if the hydrometrical form of the in-
strument were used. Hence the better form of lacto-
meter is a graduated glass tube, which is to be filled
with new milk, and allowed to repose for a certain
number of hours : then, by noting the thickness of
the stratum of creamlupon the surface, the per-centage
of cream in the milk may be ascertained. When all
the cream is skimmed from the milk, then the common
lactometer will furnish the relative amounts of curd
and whey : so that observations made by both instru-
ments may furnish tolerably accurate results, the one
for the butter value, and the other for the cheese
value, of the milk under examination.
LAKES. See ALUMINA—GARMINE.
LAMP, an arrangement for burning materials which
are fluid at ordinary temperatures, in order to produce
light. Such are the oils. Fats which are solid at
common temperatures are usually made into candles.1
The kind of oil used in different parts of the world for
burning in lamps varies with the sources of supply,
and these are numerous. In Great Britain, whale oil,
boiled from the subcuticular fat of the whale, was
long used, and still is to a certain extent, although
the general introduction of coal-gas has lessened the
demand for it. Oils obtained from seeds by pressure
are used for artificial illumination in different parts of
the world. In Paris, oil of rape-seed and oil of poppy-
seed are clarified f or lamps by filtration through cotton,
wool, and other processes. In the south of France
and in Italy an inferior kind of olive-oil is used, as
also the oil of amalzz's iiypogaea, or earth-nut. In Italy,
lamp-oil is expressed from the stones of the grape.
In Piedmont, walnut-oil is used; on the eastern and
southern coasts of the Mediterranean and in China,
oil of sesamum seed; and in tropical countries coco-
nut oil (which at the temperature of Britain is a white

(1) In the article CANDLE will be found a notice of the chemical
constitution of oils and fats.

solid like tall'ow): it‘is burnt in lamps made of‘ the
shell of the coco-nut and of bamboo. Much of the
oil used in_ China is expressed from the seeds of a
tree called camellia olezfem, cultivated for the purpose,
as is also a shrub, croz‘on sect/‘cram, from the fruit of
which a solid oil is obtained by expression. Seal oil
is used by the Esquimaux. The essential oils are too
volatile for lamps. Petroleum and naphtha from fossil
vegetable matter are used in localities which produce
them. Naphtha, the most liquid of the oils, is also
prepared by distilling fossil vegetable matter, and is
well adapted for burning. In Genoa, the streets are
lighted with naphtha from the adjacent territory of
Amiano ; and some years ago it was obtained by the
distillation of pit coal, for the purpose of burning in
the street-lamps of London. Alcohol, or spirits of
wine, is chiefly used as a source of heat, on account
of its clean flame, no soot being deposited.
A lamp differs from a candle in form rather than in
efl’ect; for although a candle is made of solid com-
bustible matter, yet this must become fluid before it
is available as a source of light.
candle is formed by the heat of the flame into a cup
of melted matter, which is drawn up to feed the flame
by the capillary attraction of the twisted wick. In
a lamp, the oil is drawn up in a similar manner, but
certain provisions are required to separate the oil
which is about to undergo combustion from the reser-
voir'which is to continue the supply to the wick. One
of the simplest methods of doing this is shown in that
contrivance for a night-light, where a layer of oil upon
the'surface of water supports a small brass cup, at
the 'bottom of which is a small piece of glass tube,
fitted tight by means of cork. Before being ignited,
the oil rises up the tube above the level on the out-
side; but when ignited at the top of the tube, the
fluid is depressed by the heat. The tube is therefore
fixed so far below the level of the oil that the greater
pressure of the oil on the outside overcomes the de-
pression within. The oil thus ignited continues to
burn with a small feeble flame. If we attempt to
increase the flame by enlarging the bore of the tube,
the oil will not burn. \ ‘ -
If, instead of this single capillary tube, we have a
congeries of tubes, such as is presented by an ordi~
nary wick, the lamp is greatly improved. The antique
lamp, Fig. 1262, consisted
of ,an extended open or ,
closed vessel, with an un-
V. _n_
spun wick rising through
a hole in the beak. With a
all its artistic beauty of i. 1262.
form, such a lamp is not superior in construction to
that with which the Esquimaux lights and warms his
snow-hut. The oil raised by the wick would vary in
quantity with the supply in the lamp; combustion
would take place only on the outside, where the air
is in contact with the flame; and as the amount of
carbon liberated from the oil is greater than can be
appropriated by the oxygen immediately surrounding
the flame, some of the carbon must escape uncon-
sumed in the form of smoke. In such a lamp, the


._ _ 5;“: r‘


The upper part of a .
106
~
shadow east by the flame considerably interferes with
its illuminating power. The shadow may be diminished
by bringing the flame forward away fromthe vessel.
6 Thustheoldkitchenlamp,Fig.
1263, has this advantage over
"" .the antique lamp, in having
the beak ' removed from the
oil vessel -;- and in proportion
as the distance between the
beak and the vessel is great,
so the‘ angleb a 0 becomes
‘more acute, and consequently
I ~ the’sh'ad'ow less. '
Fiy- 1263“ the, construction of the
immense variety ‘of- lamps which are‘ in use at the
present time, great‘ ingenuity has been displayed in
the application of physical and- chemical laws. The
objects to be attained in good lamps are :-—1. The
production of such a form of wick that the quantity
of oil decomposedby the heat, and the supply of air
required for its combustion, may stand in such re-
lation to each other, that the hydrogen and carbon
of the decomposed oil may be consecutively consumed,
and no smoke produced. 2. That the distance be-
tween the burning part of the wick and the surface
of the oil be maintained as nearly constant as possible,
so that the capillarity of the wick may be a nearly
constantforce, and the‘flame be thus supplied with
the same quantity of oil all the‘ time‘ the‘ lamp is in
action. 8. That the reservoir of _oil be so placed as
to occasion as little shadow as possible. The use
of the lamp must,_however, regulate its form: thus,
the shadow thrown by wall-lamps is unimportant, as
the lamp covers ‘the’ shadow; and in the study-lamp,
as used by one—person, the shadow is of little con-
sequence, although at all times to be ‘got rid of if
possible. a. To throw the‘li‘ght'by means of collectors
or reflectors from those parts where it is of little use
into directions'where it is most required.
Undoubtedly one of the greatest improvers of lamps
is Ami Argand'. His invention, in 1789, of the lamp
which bears his ‘name was an important step in the
i right direc-
If i , ' tion. This
invention
consists of a
burner form-
ed of two
metallic cy-
linders 0, (Z,
(Fig. 1264,)



umlmmumulumunmumrmlmmum rm ‘1;,
y ’
| nmmlmuuuumummdnhdlqw ,


EF one within
M the other :
the ainiular
space ~ be’
tween them,
which is clos-


_ ‘4 ed at the bot-
" . Fig‘ 1264', tom, contains
a cylindrical wick ‘and a portion of the oil. The oil
‘vessela a surrounds the burner. at-some distance, and
supplies thisl annular space with oil, by the tube t,

the other tube 6' being a counter support for‘ the oil
vessel. The inner cylinder is- open at the top and
bottom, ‘so that by this arrangement the flame is sur-
rounded by two concentric currents of air. This
supply of air is not, however, sufficient for the perfect
combustion of the oil as it is raised by the capillarity
of the wick. If the wick be raised so as to increase
the flame, much of the ‘carbon of the oil passes cit
in ‘the form of ' a dense smoke: if the wick be
lowered, so as to adjust the flame to the supply of
air, the flame is‘ weak and the light deficient. By
applying the principle of the chimney of a fire-
place [see CHIMNEY] tothat of'the lamp, an artificial
draught is excited; the oil ismore perfectly consumed,
greater heat is excited, and the heat becomes-the
motive power‘ for'the draught,’ ‘At first, Ai‘gand used
cylinders of sheet-iron arranged ‘above the flame as
the chimneys to his lamps; but the transparency of
glass soon caused glass chim-neys'toibe preferred. This
chimney, supported on a rest outside the burner,
included the'inner-Iand outer draught of air, and thus
exerted a powerful influence on the velocity of both
in proportion to its height. The protecting influence
of the chimney was also shown in the remarkable
steadiness imparted to the flame; for combustion not
being checked by the cold air rushing in _on all sides,-
but streaming up ‘in a- regulated 'manner through
certain apertures, the flame was placed in the condition
of a small furnace, in which combustion is rapid
but perfect, and the heat and light great in propor-
tion. The glass chimney was at first a‘simple straight
cylinder, but this was found to supply too large an
amount of air; some of that which passed through
serving not to feed the flame, but only to cool it.
This was remedied by contracting the diameter of the
glass at a certain height above the burner, as at 6,
Fig. 1264:, so as ‘to form a shoulder against which the
air should impinge, and thus be directed to the
flame.1 . . > | .
The Argand burner, from its construction, could,-
of course, be applied to any form of lamp. It would
evidently be a matter of great importance, so to
arrange the oil reservoir that the sinking of the oil,
consequent on its consumption, should have as little
effect as possible on the light,.and also that but little
shadow should be produced. In whatiis ‘called the
Astral lamp, Fig. 12641, the oil is contained in a
very flat annular vessel 22 a, so that a comparatively
iarge supply of oil occupies only a small depth.
This vessel surrounds the'burner, at; the distance of a
few inches; it receivesits supply of 1 oil through a
hole at 0:; the oil" passes : down the. tube 6 into the
annular space d d; ‘and thisbeing full, the oil may be
poured- into ‘the vessel lo 7), until the level a cor=
responds with that‘ of-tZ rZ.- ‘Now the shadow produced
by this 'oil-vessel'will be small, but it will be cast all
around; 'and'the shadow of the supporting tube 6’,

(1) This form of burner is represented at Fig. 1048, in our article
Gas-main rim, to which we must refer for further remarks on
this subject. See-also, for the structure of flame and the influence
of the wick, the‘article CAsnLn. The article FUEL may also be
referred to in connexion with this subject. "
LAMP!
‘107
and of the supporting and supplying tube i, will be
cast as shadows on the table. When this lamp is
used as a hanging-lamp, the'shadow of its oil vessel
will be cast more towards the ceiling than when it
stands on the table.
In Phillips’s Sizzum/n'a lamp, or lamp without a
shadow (sine umbm), the shadow if not destroyed is
rendered imperceptible by the peculiar form given to
- ----------------- A the circular oil vessel,
Fig. 1265. Its three
surfaces meet in the
form of a flat wedge,
_ the sharp edge of
which is directed towards the flame. The position
of the flame with respect to the oil vessel is such
that two tangents drawn from the apex and base of
the flame to the oil vessel meet a few inches behind
it in .r, Fig. 1266 5 beyond this the vessel can cast no
shadow, and even within the space where a shadow
is cast, it is destroyed by the ground-glass shade,
which rests upon the oil vessel, surrounds the
chimney, and diffuses the light around. In this
lamp the wick is moved by the following contrivance.
-.- .-_._-~>---__




~‘_
~
~__
~~~


Fig. 1266.
The inner cylinder fhas on its outer surface a deep,
much inclined spiral groove, into which the short
peg a of the wick-holder 6 fits. If the latter be
turned on its axis the peg moves along the groove,
' and forces e up and down.
a is turned by the cylinder (5,
which has a long slit in its
side, into which a second peg
12, on the outer side of 6, fits.
By this arrangement (Z can be
moved freely up or ‘down,
taking with it the wick-
holder, which is thus raised
or depressed. In order that
(Z may move easily it is firmly
attached to the support for
the chimney, and terminates
at the upper part in a thick ring, which rests upon
the edge of the cylinder 0, which is made lower for
the purpose, and thus the whole is brought up to the
full height of the biu‘ner. The supports for the
chimney are fixed in this ring, on turning which by
the hand (Z is moved at the same time, and with it
the wick. ‘
In these contrivances the oil vessel is so situated
as to interfere with the distribution of the light. In
what are called fozmiaz'a reservoir lamps, .the oil
vessel is removed to one side of the burner, so that
its shadow may fall upon the wall, or to that side of
the room where the light is least wanted. The oil
vessel may consist of an ornamental globe or.vase e,~


Fig. 1267.

Fig. I268, from the lower part of which proceeds a
tube,- the extremity of which is closed- by a thumb-
screw 8. There is also a hole in the side of the tube,
which can be opened or closed by depressing or
raising the short cylinder 8 by its handle ii. The
globe is filled by pouring oil into the lower opening
while the vessel is inverted and the hole closed. The
screw is then put in, ‘the vessel turned over and
screwed into the neck of the oil cistern 0. Now on
depressing the handle it the oil will flow out, pass
along the tube 0, and ascend to the wick as far as
the dotted line. As the oil is consumed by burning,
and falls below the level of this line, air'enters the
oil cistern through the hole w, a bubble of air passes
up through the hole, and a drop of oil falls out of the
reservoir, thus maintaining the level marked by the
dotted line. When the lamp is extinguished the
handle it is drawn up, the hole is closed, and the
supply of oil cut off. The arrows show the direction
of the double current of air, and B. is a cup. for catch-
ing anyoil that may overflow. For the sake of
clearness, we will repeat in different terms the me-





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Fig. 1268.
W is the circular wick, fixed in the wick-holder e,
which slides up and down onthe ,tube f: a small
tooth projecting on the inside of the ring 6 enters the
spiral groove 20, so that, on turning this-ring‘ round, it
slides up and down the tube f; in the groove 20,, carry-
ing the wick with it. To give motion to the ring
e from the outside, a movable tube is placed within
the tube 6 and j; and encloses the ring 6 within it.
On one side of- this tube a notch is cut from top to
bottom, and a second tooth projecting from the out-
side of the ring enters this notch. The tube rises a
little above the top of the external tube d of the
burner, and has three small wires '1" fastened to it,
which descend to the gallery I I, and are fixed thereto,
so as to support it: the same wires also fit the interior
of the glass chimney g, and prevent it from being
upset. By turning the gallery I I round, the tube,
attached to it is made to turn round, and the pro
108
LAMPS.
jecting tooth‘of the ring e communicates motion to
the ring also. At thefsame time, the interior teeth of
the ring acting in the spiral groove, moves the ring c,
and the wick .up and down i the notch in the side of
the tube which turns the ring allows it to rise or fall
without imparting a similar motion to the tube, or to
the gallery;
In order to get rid entirely of the shadow, lamps
have been constructed in which the oil vessel is
placed at the foot of the lamp, and raised by com-
plicated apparatus depending partly upon hydro-
dynamic and hydrostatic laws, and also upon the
operation of clockwork mechanism. In Gi'rard’s lamp
the oil is raised in the same manner as is the water
in a fire“ engine, viz. by the compression of air; or,
as in Hero’s fountain, in which the pressure exerted
in a vessel is transferred to another distant vessel by
means of compressed air, and is the means employed
for forcing a liquid from its previous position in
an upward direction. In Keir’s hydrostatic lamp, oil
is raised to the wick and sustained by a column
of a solution of salt and water, of such density that
it will support a column of oil % ds of its own height.
Other heavy liquids have been applied in such lamps,
such as syrup, honey, mercury, and a solution of
sulphate of zinc. The latter is 1'57 times denser
than oil, so that a column 10 inches high will support
a column of oil 15'? inches high. As the oil is con—
sumed the column of zinc would sink to a correspond-
ing level were it not that a reservoir of zinc solution
gradually feeds the column, and thus maintains the
oil to the proper level. Such a lamp has many
advantages, but one fatal defect; it cannot be carried
about, nor indeed moved, for a slight motion produces
such fluctuations between the two fluids as to extin-
guish the light. In some descriptions of lamp, the
oil is raised by a pumping apparatus placed with the
oil at the bottom. Those pump-lamps in which the
pump must be worked by hand at short intervals
have all the defects of tallow candles which require
snuifing. In (/arcel’s cloclc-zoor/c or mechanical lam];
the oil is pumped up from the foot of the lamp by
clock-work, and in such quantity as to exceed that
consumed during the whole ‘period of burning, the
unconsumed portion flowing back to the foot over-the
outside of the burner. This overflow of the oil makes
it necessary to screw up the wick higher than in
common lamps, which has this advantage, that the
flame being raised more above the edge of the burner
where less heat is conducted from it, it burns more
perfectly, no carbonaceous matter is produced on the
wick and about the edge of the burner, which usually
interferes so much with the regular“ flow of oil.
~ Carcel’s lamp has been modified and improved by
' various lamp makers: but no one has succeeded in
making it cheap. Attempts have been made to get
rid of the expensive clock-work by introducing as the
motive power a descending weight, such as a piston
in'a cylinder, or by causing a spring to act upon a
piston; but in these cases the difficulty has been to
regulate the accelerating force of the descending
weight, or the diminishing force of the spring, so as to

supply the burner'u'niformly. The method proposed
has been to contract the ascending tube conically at.
a certain spot, into which a conical plug fits. The
spring in rising enlarges the aperture at the con—
tracted spot, while the sinking piston diminishes it
by forcing the plug either backwards or forwards in
proportion as their motion is irregular.
We must not, however, omit to notice a form of
pressure lamp called the Elliptic lamp, patented by
Mr. Meyer, in which these objections are for the
most 'part removed. It is adapted to the combustion
of crude vegetable oils, and answers the purpose per-
fectly, provided the user does not object to the
trouble of regulating the mechanism—nu objection
which applies more or less to all mechanical lamps.
In this lamp the oil is contained in the foot, in a
cylindrical vessel, in which a leathern piston or valve
is worked up and down by a rack and pinion. At
the top of the solid stem of the lamp is fixed a strong
spiral spring, which exerts a constant pressiu'e on the
piston, so long as it is above the bottom of the oil-
vessel. Between the coils of this spring, and passing
air-tight through the piston, is a tube which termi-
nates in a funnel-shaped mouth in the oil vessel; this
month is covered with a perforated dish for straining
the oil. The oil is forced up this tube to the burner,
on approaching which it receives a fine silver tube,
several inches long and 3-1;, th inch internal diameter,
which is surrounded by a cup of wire gauze of tinned
copper, for straining the oil of solid particles. The
resistance offered by this narrow tube regulates the
flow of oil, which would otherwise be forced up in a
few minutes by the elastic force of the spring. The
length and bore of the tube must be so proportioned
to the force of the spring that enough oil shall be
brought up to supply the flame with a certain ad-
ditional quantity, which overflows, and thus keeps
the metal parts of the wick cool. The overflowing
portion ,returns to the reservoir at the foot. The
lamp is filled with oil at a point above the spiral
spring: it then flows down and rests on the top of
the piston. Then by winding up the rack-work with
a key, the piston is raised to the top of the cylindrical
oil vessel; the ascension tube, with the burner
attached, is then pushed down by hand through the
piston, and the oil is thus brought into a position
below the piston, and the spring in forcing the piston
down raises the oil as before described. A lamp of this
kind will yield an excellent light for 8 or 10 hours.
' In the above examples of lamps the oil vessel is
placed around the flame, at the side, and also greatly
below it in the foot of the pedestal. In Parker’s
Economic or lzol-oz'l lamp, the oil vessel is placed above
the flame; and'the object is not only to throw the
shadow in a direction where it cannot interfere
inj uriously with the light; but also to overcome the
consistency of crude whale oil, which ofiers a great
impediment to the ‘capillarity of the wick at ordinary
temperatures, so that it cannot be burnt in common
lamps unless it be first made more fluid by heat. In
the lzozf-oz'l lamp, the oil'vessel nu, Fig. 1269, is com—
posed of a double cylinder of metal surrounding the.
LAMP.
109
upper part of the chimney, and curved slightly out-‘
wards, so as to reflect the heat uponthe oil vessel;
the hot oil then descends by the arm A to the burner.


1a,]. 1269.
The lower part of the arm, which is attached to the
oil vessel, is furnished with a slide valve D, worked
by a trigger T, so that the supply of oil can be cut off
by raising the trigger, and the oil vessel removed from
the lamp to be filled. The oil is introduced by this
valve, the oil cistern being inverted, and this should be
refilled each time the lamp is used. No air must be
left in the vessel, because its expansion by the heat
would cause the ‘oil to overflow. The flame is re-
gulated by raising or lowering the bell-mouthed glass
chimney e, which rests upon 3 points below, and is
moved by rack and pinion. The wick is not movable
as in ordinary lamps, and a fresh wick, which is
accurately cut by machinery for this lamp, must be
inserted every time the lamp is used. A shade of
glass or paper surrounds the whole of the upper part
of the lamp.
It has been already stated, that volatile oils are
not, in general, applicable as illuminating materials.
This arises from the facility with which they liberate
their carbon. They may, however, be brought into
use by peculiar contrivances; either by greatly in-
creasing the draught of air, or by mixing substances
therewith which diminish the percentage of carbon.
In Berlin, for example, where oil of turpentine is
cheap, it is mixed with four parts of alcohol, of at
least 90 per cent. strength. This strength is neces-
sary, for with a larger amount of water in the alco-
hol, the flame would be too much cooled, and the oil
of turpentine be held imperfectly in solution. _ The
carbon, originally amounting to 88 per cent., or eight
times the quantity of hydrogen, is thus diminished to
63 per cent., or three times the hydrogen, which is a
much less proportion of carbon than is contained in
oil or tallow. The diminution of light from the same
weight of spirit is compensated by the greater ra-
pidity of combustion. The lamp for burning this
spirit mixture is shown in section, 1270, in which
A is the reservoir into which the burner IB descends

from above almost to the bottom. It consists of a
straight, wide metal tube a a, fitting tightly into the
real burner tube a a, which surrounds a loose cotton
wick 0 0, and fastens it by the semi-
circular piece a'. About two inches
above A, the tube narrows into (5,
and terminates in the knob c, which
is the real burner; at the base of b
are 10 or 12 holes, 5% line bore,
arranged in a circle. When the
lamp is to be used, common spirits
of wine is ignited in the cup 6 e, to '
vaporize the spirit mixture in the
upper part of the wick. ‘The vapour
which issues from b is then ignited,
and forms the flames f j; which sur-
round the knob c. The high tem-
perature of the metallic mass is then
sufficient to keep up the vaporiza-
tion, and the lamp continues to burn
without further trouble. To protect
the reservoir A from the action of
the burner as it becomes heated,
the latter is surrounded to the depth ,
of three inches with a wide case 2' i, so that a space
filled with air surrounds it thus far. The light is
brilliant but expensive.1
Lamps without wicks have also been contrived for
burning naphtha. In Beale’s steam. and vapour lamp, a
current of air traverses the naphtha, and becomes
saturated with it. This lamp produces a flame from
six to seven inches high, when supported by a double
current of air. In D’Hanen’s lamp, the flame pro-
ceeds from a knob surrounded by ten holes, as in
Liidersdorff's lamp, Fig. 1270. Both lamps produce
dazzling white flames, without smell; but the odour
of the coal tar from which the naphtha is distilled is
perceptible for a short time after they have been ex-
tinguished.
Camphine lamps have been used in this country.
Camphine is obtained by distilling oil of turpentine
over chloride of calcium, so as to free it from water.
It then contains 8846 per cent. of carbon, and 1154:
of hydrogen, '01‘ (3101-18. It thus evidently becomes
a powerful illuminating body, if properly supplied
with air for the complete combustion of its ingre~
dients; but from the ease with which it is decomposed,
much nicety is required in adjusting the conditions
under which it is consumed. .If these fail, large
flakes of soot escape unconsumed, and cover every-
thing in the room with a kind of black snow. 0r if
the camphine be not pure, a strong smell of turpen-
tine is evolved, producing headache and other dis-
agreeable ‘sensations. Mr. Young has invented an
ingenious form of camphine lamp; and so also has

Fig. 1270.

(1) In 1850, Mr. Marbe of Birmingham took out a patent for
the manufacture of a. fluid suitable for illuminations. from hydro-
carbons, alcohol, and pytoxylic spirit, &c., purified and treated
with acids, lime, alkaline, and various other substances, and dis-
tilled together. - Also for a variety of lamps, adapted to the com-
bustion of such illuminating fluid. The principle is similar to
that stated above. The same remark also applies to Brooke’s
patent, 1849, and to several others.
110
LAPIDAR'Y WORK.
Mr. Roberts, whocalls it a Gem lamp; The light is
very white and brilliant. ~ _
For some further particulars respecting lamps, we
must refer to LIGHT-HOUSE, and for a’ comparison of
the illuminative values of candle, lamp, and gas-
flames, we refer to the. article PHOTOMETER. _
LAMP-BLACK. . ‘See Cannon, vol. i. p. 315.
LAElD-ARY WORK. _.(L(lj9’l6l(lfl?€2l8, pertaining to
stones; from Lapz's, a. stone:) The art of the lapidary
does .‘not include thevarious modes of working or
finishing-stones, asits derivation would seem, to imply,
but. assented to thecutting, grinding, and polish-
ingpfjl'genis, small stones, _&c_., for jewellery, or for
niineral'ogi‘cal‘specimens.,_ '
stones _,cut by the . lapidary are of various-
degrees of hardness,1 and in cutting or polishing any
particular; stone, another harder stone is used‘, in the
form eta powder applied to the edge or the. surface
of what are ,called mills, which are disks of metal and
other materials, revolving horizontally on vertical
spindles. Thus, the slitting-mill, the roughing-mill,
the smool/zz'ag-mz'll, and the. pollslzz'rzg-mz'll, are gene-
rally of‘ metal; but for soft stones, the smoothing-mill
may be a disk of willow wood or mahogany. The
polishing-mill may be .a spiral coil of list, the surface
presented by the edges being the part used. Or
wood covered with buff leather may be used.
The processes of the lapidary vary with the hard—
ness of the stone. Alabaster as the type of
soft minerals, Carnelian as the type of minerals of
medium hardness, and Sapphire as the type of hard
minerals, three distinct groups may be formed in
which the mode of treatment corresponds for all the
members of each group.


(1) The following is the SCALE on Hnnmvnss in minerals. In
the examples selected, each mineral is scratched by that which
follows it. The use of, this scale is to determine the hardness of
any given mineral by'referen'ce to the types here’selected. Thus,
suppose a body neither to scratch nor to be scratched by fluor spar,
its hardness is represented by 4; but if it should scratch fiuor
spar, and not apatite, “then its hardness‘ is said to be from 4 to 5.
The degrees of hardness 'are numbered from 1 to 10. The third
column contains the names of some of the minerals, metals, and
other substances of similar degrees of hardness; and the fourth
column contains the number of minerals which in respect of hard-
ness are ranked under each of 'the ten grades. The hardness of
other minerals is represented in whole numbers and decimals :—
Qu- m 7-‘
a’: Q a g
S 3%‘ Types of Hardness. Examples. 5 o d . c:
3mm 0 Q,
A Z
Lead, Steatite or Soap- ..
1' Talc ' ' ’ ' stone, Meerschaum . "3
Tin, Ivory, Pot-stone, Fi-
2. Compact Gypsum . gure-stone, Cannel Coal, 90
Jet, "850. . . . . . .
Gold, Silver and Copper
3. Calcareous spar, any when pure; soft brass; 71
cleaveable variety Serpentine, Marble, Ori-
ental Alabaster, 8w. .
Platinum, Gun-metal. . 53
SoftIron . . . . . . 43
Soft Steel, Porphyry, Glass 52
4.‘ Fluor Spar, any
" cleavcable variety
5. Apatite, in. trans?
parent crystals .
6. ,Felspar, cleaveable
variety .. .
- - Hardened Steel, Silex,
7' Qt‘ggz’algglnd and {Flinig Agate, Granite, 26
P ‘ “ Sandstone, Sand . .
8, islfopafi . . . .. . Hardest Steel . . . . 6
9' Z'ggljsrfgrg qoiun'} Ruby and Corundum . . 1
10. Diamond . . . .. Cuts all substances . . l



,ALABASTER. Hardness, 1-5 to 2.
Amber. Jet. Opal.
Cannel Coal. Lava. Pot-stone.
Coral.‘ Malachite. Satin-stone.
Enamels. Mother of Pearl. Steatite.
Glass. Nacreous Shells. Turquoise.
CARNELIAN. Hardness, 7.
Agate. Elvans. Mina Nova.
Amethyst. Emerald. Onyx.
Aquamarine. Felspar. Opal.
Beryl. Flint. Pastes.
Blood-stone. Fluor Spar. Peridot.
Brazilian Topaz. Garnet. Plasma.
Carbuncle. Granite? Porphyry.
Cat’s-eye. Heliotrope. ' Quartz.
Calcedony. Jade. I Sard.
Chrysolite. Jasper. A Sardonyx .
Chrysoprase. Lapis Lazuli. Serpentine.
Crystal. Marble. Topazes.
SAPPHIREI Hardness, 9.
Mineralogists-and Jewellers apply several names to the Sap-
phire, depending on its colour and lustre‘; namely,—
White Sapphire, when transparent or translucent.
Oriental Sapphire, when blue. I . ._
Oriental Amethyst, when violet-blue.
Oriental Topaz, when yellow.-
Oriental Emerald, when green‘.
Oriental Ruby, when red.
Chatoyant, or Opalescent Sapphire, with pearly reflections.
Girasol Sapphire, when transparent, and with a pale-reddish
or pale—bluish reflection.
Asteria, or Star Sapphire, has six milk-white rays, radiating
from the centre of a hexagonal prism, and placed at right
angles to its sides. The Asteria is found in both the red
and blue varieties, of Sapphire, and is alwayscut so as to
show the figures.
All the above Sapphires, the Chrysoberyl, the Zircon, and some
other gems, are cut with diamond powder, and polished with
rottenstone.
Fig. 1271 represents the lapidary’s bench. It con-
sists of a stout plank, about three feet six inches long,
and one foot nine inches wide, supported on a frame
about two feet six inches high- The top is divided
into two unequal compartments, and a rim rises about
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‘I i mlllllt'rmy
. _ Fig. 1271. _ ‘
two inches above ‘the top, to catch the waste emery
and water thrown off by the mill. In the left hand
compartment‘ is a hole and a collar, through which
passes the vertical spindle of the driving wheel a,
the lower conical end fitting in a rail of the frame.
The driving wheel is about eighteen inches in
diameter, and works just below the under surface of
the bench top: it is worked by a horizontal handle a.
In the right-hand compartment, the spindle cl carries
TIAPIDART- WORK.
111
the mill, which is about 8 or. 9 inches ‘diameter, and‘
revolves about an inch above the surface of the bench:
but it may be adjusted ‘by means of .a flange and
screwed nut to a greater or less distance, according
as the edge or side of the mill is required to be used.
In the figure, the lower centre is a square wooden
rod, passing through a mortice in a transverse rail of
the frame, and kept to the desired height by a side
wedge. By this contrivance, lap spindles of various
lengths may be accommodated. The top end of the
spindle also works in a wooden centre, screwed into a
hole near the end of a horizontal iron arm e, which
slides upon a perpendicular bar j; and is retained at the
proper height by the binding screw g. The pulley is
about 4 inches in diameter, and is fixed on the
spindle just below the bench top. A little to the
right, and in advance of the lap, is an iron support iz,
called a ginnpeg, or germ-peg, about 8 inches high, and
in the form of a crank: it is secured below the
bench by a wing-nut, so as to allow the peg to be
moved round to different distances from the lap, as
may be required. Its use is to support the arm of
the workman in grinding the edges of small stones,
and also to serve as a guide for the vertical angle in
cutting facets, for which purpose a wooden socket,
shown ‘in the figure, is slipped over the upper part of
the rod, and held in its place by a wedge. Holes or
notches, iarranged round the sides of the socket, serve
to determine the inclination of the stick upon which
the stones to be out are cemented.
"-In producing a plane surface upon an irregular
piece of stone, as in smoothing a mineralogical spe-
cimen, if the natural surface be nearly flat, it may be
at once applied to the flat surface of the roughing-
mill; and if the stone be soft, such as a piece of pot-
stone, a flat surface will be quickly formed; but if
the natural surface be irregular, and the stone be
hard, as a piece of blood-stone, or even an ordinary
pebble, the process of grinding would be too tedious.
Splitting or cleavage can seldom be adopted, since the
stones wrought by the lapidary have not often a suffi'
ciently lamellar structure to allow of plane surfaces
being produced in this way. And besides this, flaws
or veins might interfere with the surface. In most
cases a plane surface is produced by cutting off a thin
slice of the stone with the slitting-mill or slicer,
which is a disk of thin sheet-iron, charged on the
edge with diamond powder, and used as a circular
saw for dividing all stones inferior in hardness to
the diamond.
The use of diamond power is very general. Mr.
Holtzapffel remarks, that “notwithstanding the ap-
parent expense of the diamond powder, it is very
generally employed, and is used for cutting nearly
every Turkey oil-stone that is sold; and, although for
this and some of the softer stones emery, or in some
cases even sand, might be successfully employed,
. the diamond powder is almost exclusively used, as it
is found to be the most economical, when the time
occupied in the cutting is taken into account. The
diamond powder cuts more rapidly than emery, and
is very much more enduring: it also admits of being

employed with very' thin plates, and‘ consequently
the progress is also more expeditious on this account,
and comparatively only a small thickness of material is
wasted in the cutting. This is sometimes an important
object with ‘valuable stones, and the slicer is then
made of small diameter, in order that it may be as
thin as possible, and still retain the required degree
of stiffness.” Diamond powder is prepared from
born, [see Cannon, vol. i. p. 311,] from imperfect
diamonds, and the fragments removed by the jeweller
in splitting ,or cleavage. These fragments are
crushed in a mortar, Fig. 127 2, containing a deep
cylindrical hole, terminating in the bottom in a sphe—
rical cavity of hardened steel, into which the pestle
6 accurately fits by grinding. This form of pestle
and mortar is adopted to prevent the valuable dust
from being scattered about; the
cover 0 is added with a similar in-
tention. When the diamonds have
been put into the mortar, the pestle
is thrust down, and struck a few
blows with a light hammer, twist-
ing it round. after every blow. The
crystalline structure of the diamond
renders it brittle, and hence it is
crushed without difliculty, although
it stands alone'and with the highest
number on the scale of hardness.
If the powder be not crushed sufliciently fine, it is
mixed with a little olive oil or oil of brick spread
upon a flat piece of iron, such as an old laundry iron,
and another small piece of iron is used as a muller.
Oil of brick is generally preferred as the vehicle for
the diamond powder. Its advantages are its lim-
pidity, and its not being liable to thicken by exposure
to the air.
The slicer is of sheet-iron 8 or 9 inches in diameter,
and 2(‘,oth of ‘an inch in thickness. In order that it
may run in one plane, and not be distorted by the
resistance of the work, it is planished or hammered
into a slightly arched or disked form. This causes
the edge to run true, and when it has cut a small depth
into the stone, the trifling curvature of the disk gives
way, and it is flattened by the groove it has cut, and
in which it is compelled to run. The diamond powder,
formed into a paste with oil of brick, is applied to
the edge of the slicer with a small piece of stick or
a slitted quill, and when uniformly distributed, the
particles are fixed into the» iron by gently pressing a
piece of agate or flint against the edge. As soon as
the diam end-dust begins to cut the stone, another
part of the edge is operated on in a similar manner.
Any particles of the powder which escape to the
sides of the slicer, are wiped off with the finger,
pushed to the edge, and pressed inwith the chargmg-
stone. With a new slicer, this seasoning, as it is
called, must be performed a second time. When
once properly seasoned, the slicer can be used for
several hours, after which its cutting edge may be
restored by a single application of the powder.
Before beginning the operation, the stone should
be washed clean and dried, and the line of the


Fig, .1272.

112
'Lxrmn'nv wo'nx.
intended section marked with ink as ‘a’ guide. The
stone, held in the right hand, is applied lightly to the
edge of the slicer, which is made to revolve with
moderate velocity by turning the handle a, Fig. 1271,
with the left hand. During the‘ slitting, the slicer
must he kept well supplied with oil of brick; and
care must be taken to keep the cut in a straight line,
the dished form of the slicer making it' liable to cut
upwards.‘ A tolerably smooth ‘surface, not an angle, .
ought first’ to‘ be presented to the slicer, to prevent
the diamond powder from being torn off. _ Amoderate
velocity and‘ pressure are desirable to prevent the
effects of heating. If the stone is too large and heavy
for the hand, it is mounted on a crane, consisting of
an upright rod moving between centres just in front
of the" perpendicular bar f; Fig. 127 3, and upon this
' rod slides vertically a horizontal arm j, which is fixed
to the red at any height byimeans of a binding screw.



l l
"1 w-
?‘ l‘



l
- Fig. 1273.
The stone is fixed to the arm by a clamping piece and
two binding screws, and is drawn forward by a weight
1: attached to a line leading from the extremity of
the horizontal arm over a ‘pulley. In this way the
stone is kept up to the edgeof the slicer, which the
operator keepsfin motion, and supplies with oil. For
cutting ‘ parallel slices, the horizontal arm must be
shifted after every cut. ~ '
' The flat surfaces thus produced are ground upon
the roughing-mill to remove the marks of the slitting-
mill. The roughing-mill is ‘a lead lap, and is kept
supplied with'emery and water. If the stones are too
thin to be held by hand,- they ‘are cemented to 'a disk
of wood with a handle of the same material. In
charging the lap,‘ the ‘emery is ‘rubbed into it with a
smooth lump of emery- stone, or-a ‘piece of iron. The
emery and water are then applied with ‘a brush, and
as the work proceeds, finer emery is ‘used. The stone
is applied flat to the surface of the mill, and pressed
against it with‘moderate force.
'- When ‘the stone has been sufficiently smoothed, it
is’ polished on a‘ lead or pewter mill well'supplied
with ‘rottenstone and water ;' but as this fine powder
will not adhere by simple pressure'as the emery does,
thejface of the polishing-lap is lzackcd or jarred with
the blade of an old table-knife, held near the middle
between‘ the thumb and finger, with the edge on the
lap. _ On turning this round, the blade is made to
vibrate or jump oni-the lap, and at each jump it pro-
duces va slight furrow. ~ this way the face of the
mill is covered 5with minute lines or grooves, which


serve to hold and retain the finely-powdered rotten‘
stone.
If the stone is to be worked into a definite shape,
such as an oval, a pattern is cut out in card, placed
upon the stone, and its outline marked with ink upon
it. The stone is then brought very nearly to the
shape required by means of flat nippers of soft iron,
which being firmly compressed upon the stone, and
then twisted sideways, break off small particles.
When by this contrivance the stone is brought nearly
‘into shape, it is ‘cemented upon a stick, the edge being
leftiexposed, and is ground by holding the stick hori-
‘zontally, at the ‘same time constantly "twisting it
round. This will produce a square edge; but if a
bevel or chamfer be required, the stick must be held
at an angle, and twisted round as. before. If a
rounded edge be required, the stone is first pre-
pared with a bevelled edge, and the angle is then
removed by arocking motion of the stone upon the flat
mill. Rounded and elliptical faces are produced by
peculiar ‘rolling motions of the wrist, and it is sur-
prising what accurate
results are produced
by working lapidaries
by a cultivation of
the sense of feeling.
Stones that are flat on
the back, and much
rounded on' the front, /
are called tallow-lope,
from their ' resem-
blance to a drop of
tallow. In cutting facets, the stone is applied to the
mill as shown in Fig. 12711, the gim-peg being
adjusted so' that on inserting the end of the stick in
one of the notches of the wooden socket the stick is
inclined at the proper angle. All the different forms
of facetting, which are numerous, are usually cut by
practical lapidaries without any other guide.1
- Stones that are rounded to a cylindrical or conical
form, such as a' drop for an ear-ring, are cemented
sideways upon a stick, and one half ground to the
shape required. They are then detached from the
stick, and cemented with the; other side exposed.
When this has“ been ground, the stone is successively
cemented in two other positions at right angles to
the first two, so as to connect the junctures of the
two curved surfaces first produced. Stones that are
to be ground into spheres for heads or the heads of
pins, must also be cemented inat least four positions.
The lap used for grinding flat surfaces is not used for
rounded ones; The lap‘which ‘is used becomes worn
intoi‘n'umerous ‘hollows of different sizes,- some of
which fit the‘ curve'_ ofthe- ‘stone under operation.2
“ Stones that are semiftiansp'arenQsuch " as garnets,
are frequently‘ left round' on the face, or cut ca
ca'oocfioa; but such stones, if left of the full thick-
‘ (I) In the 30. vol. of‘ Holtz—apfi'el’s “Mechanical Manipulation,”
a minute accountisegivenof the art of cutting facets. In our
article Cannon, vol. i. p. 307, is a brief notice of the method of
cutting and polishing diamonds. - . , .
(2) In the INTRODUCTORY ESSAY, p. cviii., is an account of the
method of making agate beads as practised in India.


LAPIDARY WORK—LAVENDER—LEAD.
113
ness, would be too opaque to display much brilliancy;
and therefore, with the view of increasing the transpa-
rency, garnets cut an ealoclea, and called carlaac'les,
are generally hollowed on the under side, to make
them thinner. The hollow on the under side is
ground upon~ small spherical grinders of lead, called
halls, made of various thicknesses and diameters, but
mostly of the size of bullets. The halls are mounted
upon a small conical spindle fitted to the lapidary’s
bench; the hole through the balls is also made
slightly conical, so that they may be retained upon
the spindle by the plain fitting, and allow of being
readily detached for the substitution of other balls of
different sizes. Similar balls made of pewter are
employed for polishing.”
The foregoing details will convey some idea of the
lapidary’s art. We shall have to treat of a somewhat
kindred subject in om‘ article SEAL ENeEAvINe, and
in noticing the gems and precious stones under their
respective names, some details are given as to the
methods of cutting and polishing them. Under
Grrsuin', the method of cutting and polishing ala-
basler is described.
For the use of the amateur lapidary, Mr. Holtzapffel,
has contrived an elegant and convenient apparatus,
which is described in his admirable work already re-
ferred to, and may be inspected at the shop of his
widow, 64', Charing Cross, and 127, Long Acre,
London.
At Amsterdam, where most of the diamond cutting
is. performed, the steam-engine has recently been
employed to give motion to the mills, by which means
a great saving in labour is effected, and a very much
greater speed produced- At the time this article is
going to the press the celebrated Koh-i-noor (whose
want of brilliancy excited general disappointment at
the Great Exhibition) is being recut in London, under
the superintendence of some artists from Amsterdam,
in a more artistic manner, in order to enhance the
brilliancy of this fine gem. The mill which operates
upon it is made to rotate 2,400 times per minute.
LAPIS-LAZULI or LAZULITE. See ULTRA-
MARINE.
LATHE. See Tunnrna—Also Inrnonucronv
EssAY, p. cxxxvi. '
LAVENDER, the name of hoary, narrow-leaved,
fragrant bushes, with generally blue flowers, arranged
in close terminal simple or branched spikes. Twelve
species have ‘been described, only two of which are
of much interest, viz. the common lavender (Lawm-
clala vera), and French lavender (L. spica). The former
yields the fragrant oz'l cf lavender used in perfumery,
(its solution in spirits of wine forming what is called
lavender-watery) and the latter oz'l qf gpi/ce, used by
painters on porcelain, and in the preparation of var-
nishes for artists. [See ESSENTIAL OILs.] English oil
of lavender is most esteemed : it is prepared chiefly at
Mitcham in Surrey, where the plant is extensively
cultivated for the purpose. It is in highest perfection
when about a year old. At first it is nearly colour-
less, but gradually acquires a pale amber tint. Oil of
spike is chiefly imported from the South of Europe.
voL. II.

LEAD. The chemical symbol for lead is Pb, from
plambam .- its equivalent number is 101.1‘, and its
‘density 11°35.
SECTION I.-—-METALLURGICAL His'ronr or LEAD.
Lead was well known to the ancients, and is fre-
quently mentioned in our translation of the Bible,
and in those cases where fin is mentioned it has been
supposed that lead of some kind is meant. The
Hebrew word lezlz'l has been translated lz'a; which
term the Greek translators of the sacred books
rendered Kdaalrepos; and this last word has been
translated by more modern writers by slamzam.
Beckmann, in his “ History of Inventions,” has a
learned essay on the meaning of the three works leclz'l,
Kao'o'l'repos‘, and slamzam; and although he does not
settle the point, he does not dispute the fact that
lead was in extensive use by the people of antiquity.
Camden on the authority of Pliny says :--“ In Britain,
in the very upper crust of the ground, lead is dug up
in such plenty, that a law was made on purpose to
stint them to a set quantity.” To what extent the
lead ore was worked by the Britons, or by the people
who visited them for the purposes of trade, is not
known; but there is no doubt that under the govern-
ment of the Romans the lead of Britain was an
important article of commerce. Blocks or pigs of
lead have been discovered with Latin inscriptions on
them; and in the neighbourhood of the mines are to
be traced the remains of Roman stations, houses, and
burial-places. The Saxons after the departure of the
Romans continued to work the lead mines, one of
which near Castleton was dedicated to Odin. The
mines near Wirksworth were wrought before the
year ‘714*, for we read of a sarcophagus of lead lined
with linen having been prepared in this locality. In
the year 835 the mines of “ VVircesworth ” were sur-
rendered to one Humbert, on payment of an annual
rent of lead to the value of 300 shillings for the use
of Christ’s Church, Canterbury. InDoomsday-book
the mines in the Peak and in the wapentake of Wirks-
worth are referred to as the peculiar domain of the
sovereign. In the records of the Duchy of Lancaster,
the Derbyshire lead mines are designated as ‘f The
King’s Field.” The mines until a recent period were
regulated by ancient laws and privileges, which
empowered all persons to dig and search for veins of
ore without being accountable to the owners of the
soil for any damage done to the surface or even to
growing crops. It is now held that unless a miner
procures ore enough from any vein he may be in
search of to free the same; that is, to pay to his
farmer or lessee a dish of ore, he is liable to the
owner for any damage committed in the search.
In the King’s Field a mineral court is held under
the. presidency of a bar-master, who, assisted by a
jury of 241 miners, decides all questions respecting the
duties or cope payable to the king or his lessee : they
also regulate the working of the mines by those
to whom the bar-master has given possession; and
in certain cases enforce the payment of debts in-
curred in working them. These laws, as Mr. Farey
I
114
*
remarks,‘ ‘evidently ‘originated in the :very infancy of
mining, and were adapted to the working ofithe mines
entirely by manual labour. A person having found a
vein .of- ore, made certain crosses .on the ground, as a
markof ‘temporary possession, and then _informed the
bar-master, who attended and received a dish of fore,
the ‘first produce of the mine, as the condition of
permitting him to proceed in working his meer“ or
measure of’ 29 ‘yards in length of the vein. At the
same time the bar-master took possession of the next
iadjoining'lég- yards or half-meer of the vein for the
king. " ~If 'the'vein seemed promising, it often hap-
penedjthat other persons applied to be‘ admitted, each
to free his meer or 29. yards in length of the rake
vein in succession. It was a condition that each
person,-or company, possessing their meer or meers
in partnership, called groove-fellows, should imme-
diately begin and continue to work at their mine;
and in case‘ of intermission for 3 successive weeks,
the bar-master was authorized to dispossess them and
give the mine to another.
~ The King’s Field comprises the greater part of the
mountain limestone district of Derbyshire. In the first
meers or mines the limestone had no other coverthan
the soil. The miners worked with mattocks or picks, and
with hammers and iron wedges in the harder veins, re-
moving the ore, and throwing out the spar and rubbish
on each side ofv the vein. Having worked the vein
to a certain depth, they erected a square frame, com-
posed of at narrow planks of wood placed across and
pinned at the. corners ; on this frame 2 upright posts
were erected with’ holes or notches to receive the
spindle of a Windlass for winding up the ore in small
tubs. This apparatus, called a stowse, being erected
on each meer, the working was continued to the
depth of ‘ many yards; the heaps of rubbish mean-
while accumulating on eachside. many hundred yards
in length, with other similar ditches and heaps from
other meers. crossing them in- various directions.
When the miners in- this way had excavated as low
down as their simple means permitted, or when the
'ore ceased to be profitable, the meer was abandoned;
but as in after times other adventurers might ‘appear
and carry on the work, the poor farmer of the land
thus disturbed was forbidden by strict laws from
returning the- barren rubbish into the deep. and
dangerous ditches thus. excavated. Mr. Farey saw
numbers of these ditches in the state in which they
had been left by the miners, altered only by the tread-
ing of cattle and the natural .mo'ulderingsof the sides.
‘In. some cases a better system was adopted. In rich
‘mines, instead .of throwing all the rubbish to the
surface, it wasv thrown upon floors or stages of wood
called jdmzm'rzgs, placed across the whole length of the
‘mine except just under the stowses, at which places
they sunk 6 or. 8 feet lower 5; and after clearing some
distance, erected other- bunnings, under the former,
‘on which the refusewas thrown as before. As the
‘work proceeded, :the shaftfunder the 'stowses was
lined; with timbers: or stone ; and the vein-stuff being

' (1 )j 1,“ surveyor‘ the Agricultural‘ and Miiieral Districts of Derby—
"shire." -;3 vols.‘ 1811, .1813, and 1317.

thrown on the bunnings around it, a regular hill was
at length-formed called the. fiz'lloc/o, or' the mine lzz'Zlock.
In the: course of time the laws which required a
working stowse to be used once in 3 weeks for draw-
ing ore at each meer, became so far relaxed as to
allow models of stowses, or small sham ‘drawing
apparatus, made of thin laths of wood which the bar-
master provided, tobe used as the means of keeping
possession of all the meers but one on a consolidated
mine; a custom which still prevails, and is so rigidly
enforced, that a mineon which large steam engines
may have been long used is not held to be legally
occupied unless one of these pigmy memorials of the
primitive mode of drawing ore is constantly kept “ in
sight of all men,” as the law expresses it, and others
on each of the meers of ground or lengths of 2.9 yards
of which the mine consists. Persons detected in
removing or destroying the bar-master’s stowses,
wherever or however inconveniently they may be
placed, are liable to certain penalties. These models,
to be effective, must have no nails in their structure,
but be pinned together with wood as was the case
with the original machines. If a known unoccupied
vein cross a paddock, a garden, or a gentleman’s park
within the King’s Field, it must be leased of the bar-
master by the 'payment of a dish of ore, and the
erection of these sham stowses, and even a real stowse,
which must be worked periodically in however slight
a manner. If this be omitted, any person on applica-
tion to the bar-master may take possession of such
vein, and destroy the. land in pursuit of it. Such
laws as these greatly interfere with the culture of
the land, espebially when it is considered that there
are many veins of ore which are too narrow or too.
poor to be worked with profit; and yet to prevent
needy adventurers from claiming them it was neces-
sary to keep the land stowsed even on the barren hills
of grit-stone rocks and the coal measures.
All lead ore which is dressed ready for sale in the
King’s Field is required .to be measured in the
presence. of the bar-master before. it is removed from
the mine: for which purpose a rectangular box called
a disk is used in the Low Peak. It is 28 inches long,
6*wide and 4." deep, and is reputed to hold 141 Win-
chester pints when level full. In the High Peak 16
pints are reckoned to the dish. In measuring the
ore, every 25th dish is set aside by the bar-master as
the King’s lot, cope, or duty.
By an act passed in the 15th and 16th Victoria,
the short title. of which is “‘ The Derbyshire Mining
Customs and Mineral Courts Act, 1852,” most. of the
inconvenient and absurd old customs so long com-
plained of are modified. or abolished. It is lawful by
this. act for all, subjects of the realm to search for
veins of lead .ore, and dig mines in any kind of land,
except in places for. public worship, burial grounds,
dwelling houses, orchards, gardens, pleasure grounds,
and highways: but if no vein of ore be found, the land
must be, levelled’ and made good at the expense of the
person making the search ; and if ore be found, a pro-
per; recompense must be. made to the occupier of the _
land forany damage done. The landowner has also
LEAD.
ll 5
the power of removing andidisposing of the eaZ/afecgle, .
spar, and other ‘minerals and rubbish, and even such as
contains lead ore‘, if left for 18 months on the ground.
The dish or measure for measuring the ore is to
contain 15 pints of water.
The bar-master, with two of the grand-jury, provide
the miners a way either for foot passengers or carts
from the highway lying most convenient to the mine,
and also from the mine to the nearest running stream
or spring of water; but the miners are not to defile
the waters of running streams so as to render them
injurious to cattle.
If any mine he left unwrought, and there be ‘no
reasonable excuse for such neglect, such as want of
water, &c., the bar-master may direct the same to be
forfeited, and in the presence of two or more of the
grand-j ury may give such mine to any person willing
and able to work it.
This act contains a variety of other minute details
for the regulation of the mining property of Derby,
and also settles the constitution of the Barmote
courts, defines the duties of the stewards, bar—masters,
and other ofiicers, and gives scales of fees, forms of
proceedings, &c. &c.
In addition to those of Derbyshire, there are also‘
lead mines in Allendale and other western parts of
Northumberland;1 at Alston Moor, &c., in Cum-
berland; in the western parts of Durham; in Swale-
dale, Arkendale, and other parts of Yorkshire; there
are also mines in Salop; in Cornwall; the Mendip
Hills in Somersetshire, and in the Isle of Man. The
Welsh mines are chiefly situated in the counties of
Flint, Cardigan, and Montgomery; those of Scotland
in Ayr, Kirkcudbright, and Lanark; and those of
Ireland in Wicklow, Waterford and Down.
The following table shows the produce of lead for
five years in the above districts :—




1845. 1846. 1847. 1848 1849
tons. tons. tons. tons. tons.
Devon and Cornwall... 7,188 5,947 8,333 7,458 8,045
Northern Counties 28,820 27,621 28,387 28,893 30,781
Ireland..................... 855 811 1,380 1,188 1,653
Scotland 901 942 822 1,736 957
South Wales ........... .. 4,807 5,084 6,419 4,053 5,941
North Wales 6,207 4,943 5,875 7,069 7,448
Shropshire ; ............ .. 2,500 3,200 3,000 2,800 2,310
Pig lead is worth about 16L per ton. A few years
ago it was calculated that of the 55,000 tons, which
is about the average annual quantity of lead produced
in Great Britain, about 25,000 tons yield 802. per
ton of silver, or 200,000 oz., which at 58. per oz. is
equal in value to 50,0001. a-year.
In 1849 our exports of lead were of the declared
value of 287,737L, and in 1850, 387,575Z. France
takes the largest quantity ; Holland, Russia, and the
East Indies are our next best customers. The
exports in the latter year were as follows :—
Tons. cwt. qrs. lbs.
165 17 0
Lead ore...... O
Pig and rolled lead 20,165 18 1 1
Shot . 1,750 9 3 19
Litharge................... .. .. 562 1 2 13
Red Lead 2,112 0 3 8
White 2,043 17 2 4

(1) The lead mining district ‘of Allenheads is more particularly
noticed in our Ix'reonucromr Essar, p. xcviii.

The lead mines of the United States of'A‘merica
have of late years ‘become of great value and imports
ance: they are for the most part situated in Illinois
and the Wisconsin territory.
summon II.—Lnan AND ITS CoMrouNns.
Lead is of a bluish-grey colour, and of a strong
metallic lustre when the surface is‘ clean, or recently
cut; it is soft, and leaves a black streak on paper.
It is flexible and non-elastic; it can be rolled into
thin sheets, and drawn into wire, but it is inferior
in tenacity to most of the other ductile metals.-
It fuses at about 612°,‘ and when. slowly cooled
it forms imperfect octahedral crystals. It is volatile
at a red heat, but not sufficiently so to admit of
its being distilled. It contracts on cooling, but by
being repeatedly heated and cooled it becomes per-
manently enlarged: this may be noticed in the case
of a leaden wash-hand basin which is frequently
made to contain hot water. In castings of lead
which are rapidly cooled there is generally a cavity
due to the contraction in cooling, which in rifle bullets
is found to interfere with the rectilinear passage of
the ball.
out of rolled lead. The density of lead is said not
to be increased by hammering, but the metal becomes:
hot under the hammer, and opens into fissures. ‘
In distilled water, previously boiled to expel the‘
air, and preserved in close vessels, lead undergoes no'
change; but in' open vessels it soon becomes oxidized,
and the carbonic acid of the air, combining with the"
oxide, produces minute, shining, brilliantly" white
crystalline scales of carbonate of the‘ protoxide. If
a minute portion of salinefmatter be present in the
water, the oxidation of the lead is retarded, and some
salts‘ prevent it altogether. The preservative power
of neutral salts appears to be due to the insolubility
of the compound which their acid is capable of forming
with lead. Thus phosphates, sulphates,v chlorides;
and iodides, are highly preservative; so smalla quan-
tity as mth part of phosphate of soda, or iodide
of potassium, in distilled water, preventing the cor-
rosion of lead. In a preservative solution the metal
gains weight during some weeks, as its surface be;
comes coated with carbonate, which is slowly decom;
posed by the saline matter of the solution, and the
metallic surface being thus coated with an insoluble~
film, which adheres tenaciously, all further change
ceases. In cases where danger is likely to arise from
the use of lead pipes or cisterns, Dr. Christison
recommends that they be first filled with a very weak
solution of phosphate of soda, by which they will be
covered with an insoluble protective film. Many
kinds of spring water do not corrode lead, on account
of the salts contained in them, and hence may be
safely collected in leaden cisterns ;~ but such cisterns
should have wooden not leaden covers, because the
vapour from the water in the cistern condens-
ing upon the under surface of the cover, is pure
distilled water, i and will corrode lead. Another
source of danger from lead arises from voltaic action,
as where iron or copper bars, screws, or pipes, are in
Hence rifle balls are sometimes moulded‘
I 2
116
LEAD,
contact‘ with or soldered into lead, and 'it may .be
acted on by alkaline bases, or by acids, according to‘
theelectric state“ in which it may be thrown by the
metal in contact. Piecesof mortar which have fallen
by accident into‘ leaden cisterns, will corrode and eat
holes ‘through them, the lime of the mortar oxidizing
the metaL'and assisting in the ‘solution of the oxide.
The use of leaden vessels frequently ~~leads to the
contamination of various articles by oxide of lead.
Ghevreul has detected lead in certain liquors kept in
flint-glass bottles, and the dyer and calico printer is
sometimes‘ embarrassed by the presence of minute
quantities of lead in his dyer'stuffs, or in the water of
his cisterns.
The most recent investigation of the action of soft
water on lead is that by Messrs. Graham, Miller, and
Hofmann, the more important results of which are
stated in the Report “ on the chemical quality of the
supply of water to the Metropolis,” (1851,) from
which we abridge a few details. The corrosive action
of the soft spring waters of Surrey was found to be
very small, with the exception of the water from the
Punchbowl at Hindhead, of which the power to dis
solve lead was rather considerable. The former
waters contained only a very small quantity of dis-
solved oxygen. River or spring water from the chalk
strata, softened artificially to about 3° of hardness}.
was found to have no dangerous action uponlead.
The protective character of the sulphates did not
appear to be uniform in its action ; while some salts,
such as chlorides, and more particularly nitrates, may
increase the solvent action of water on lead. Of all
protecting actions that of carbonate of lime dissolved
in carbonic acid appeared to be the most considerable
and certain. The effect of a very small quantity of
carbonic acid was found to be very remarkable in
neutralizing the usual solvent action which water
exercises on'lead through the agency of the dissolved
oxygen. The soluble oxide of lead is converted into
the carbonate, which although not absolutely in-
soluble, appears to be the least soluble of all the
salts of lead, Pure water did not dissolve more than
T515th of a grain of carbonate of ‘lead to the gallon of
water, or one part of lead in 4.! millions of water;
while water which already contained as much as six
grains per gallon of oxide of lead in solution, had
the quantity of metal reduced to 317th of a grain by
free exposure to the atmosphere for twenty-four
hours, the lead being deposited as carbonate of lead
in consequence of the absorption of carbonic acid
gas. These quantities also represent pretty closely the
proportion of lead which was dissolved by water left
in contact with the metal in a divided state for
twenty -four hours; ‘in one experiment distilled water
was used, and in the other water containing three per
cent. of its volume; of carbonic acid. The pure water
became highly poisonous, while that containing car-
bonic acid ‘remained ‘safe. Carbonic acid’ is usually
present in well, lake,- and river waters in sufiicient
quantity for‘ protection, and- the freedom of such
waters from lead impregnation is ascribed rather to

(I) This termis explained under Frn'raa'rxon, v01. i. p. 649.

their carbonic acid 'than'to the ‘salts contained in
them; for lead placed in distilled water which had
been boiled to expel its carbonic acid is no longer
Sufiiciently protected by the addition of the same salts.
An excess of carbonic acid may render carbonate of
lead soluble, as it does carbonate of lime, but not by
any means to the same extent; moreover, this excess
of carbonic acid is very unusual. The presence of
organic matter, such as decaying leaves and impurities,
is doubly dangerous, as the rapid corrosion which it
occasions may be followed by solution of the lead
salt formed when the carbonic acid is either deficient,
as in rain water generally, or in‘ excess.
Dr. John Smith of Aberdeen made some careful
experiments to ascertain the action of the water of
the Dee on the leaden pipes by which it is served.
The water is under lac’ of hardness, and is distributed
by iron mains, and taken into the houses by leaden'
pipes, varying from 12 to‘ 100 yards in length, to
which leaden cisterns are attached. The supply is
constant, and amounts to about one million gallons a
day. In some instances no indication of the presence
of lead in the water which had passed through the
pipes was found; in others small quantities were dis-
covered in solution; these varied from 1530th to about
z—lgth of a grain in a gallon of water. No injurious
effects could be traced to the use of water containing
this minute quantity of lead, and the commissioners
conclude “that the danger from lead in town-supplies
of water has been overrated, and that with a supply
from the water companies not less frequent than
daily, no danger is to be apprehended from the use of
the present distributory apparatus, with any supply
of moderately soft water which the metropolis is
likely to obtain.”
The lead of commerce is tolerably pure. It may
be obtained pure by reducing in a crucible oxide of
lead obtained by the decomposition of crystallized
nitrate of lead. Hydrochloric acid, even when 0011-
centrated and boiling, acts but feebly on lead. Weak
sulphuric acid does not act upon it when the air is
excluded, but if heated in strong sulphuric acid,
sulphate of lead is formed with evolution of sul-
phurous acid. Nitric acid oxidizes lead with rapidity,
and forms with its oxide a nitrate which crystallizes
on cooling in opaque octahedrons.
Chemists are acquainted with four oxides of lead,
only one of which has basic properties. The protozrz'de
PbO, also called Zz'flzarge and mass'icoz‘, may be pre-
pared by heating the carbonate to dull redness.
When pure it has a delicate straw-yellow colour; it
is very heavy, and slightly soluble in water. It melts
at a red heat, and in this state‘ attacks silica with
ease, penetratingan earthen crucible in a few minutes.
Hence its use in the manufacture of flint glass. It
forms salts with many of the acids. By exposing
the protoxide for a long time to the air, at a tempera—
ture of between 57 0° and 580° the red oxide Pbg O4 is
formed. It is known by thev terms and red
lead. It is used as a pigment, and as a substitute for
vermilion. To obtain it of a brilliant colour it should
be madeinlarge quantities; but its brilliancy becomes

LEAD.
117
dimmed by exposure to light. The most brilliant
minium, called orange mine, is said to be obtained by
heating and stirring in iron trays pure carbonate of
lead in a current of air at a temperature a little
under 600°.
In the ordinary manufacture of red lead a rever-
beratory furnace with a double hearth, one above the
other, is used, in the lower of which the temperature
is highest; here the metallic lead, which is used as
pure as possible, is converted into massicot, care
being taken to avoid the fusion of the oxide, for that
would delay its conversion into minium. The massi-
cot thus produced is usually levigated, washed and
deposited, in order to get rid of particles of metallic
lead: it is then placed on the upper hearth, which
is heated by the waste heat of the lower one. It is
spread in a thin layer on the hearth, and the surface
is renewed from time to time by raking, or it is placed
in shallow trays of sheet-iron, arranged upon the sole.
In some cases a single furnace is worked by day for the
conversion'of the metallic lead into massicot: this is
put in quantities of 50 lbs. into iron trays, which are
piled up and exposed during the night to the residuary
heat of the furnace, whereby the massicot absorbs
more oxygen, and becomes partially converted into
red lead. The operation must be repeated twice
before the lead is of the proper colour.
The other two oxides of lead are the peroxide Pb02,
and the saéoaz'de Pb2O.
Salp/zale and plosplale of lead also exist as ores.
The e/zromale is found in small quantities; it is the
elzrome yellow of painters, and is prepared artificially
by adding a solution of ehromate of potash to a
soluble salt of lead. '
Native lead is rare; but specimens of it have been
found associated with galena in the county of Kerry,
Ireland, and in an argillaceous rock near Carthagena,
in Spain. It has also been found at Alston Moor.
Lead is usually found in combination with sulphur,
but it also occurs with oxygen, selenium, arsenic,
tellurium, and various acids. The ores of lead, with
one‘exception (plumbo-resinite,) are fusible before the
blowpipe; placed on charcoal with a little carbonate
of soda as a flux, a fragment of an ore will yield a
globule of metallic lead.
Native oxide of Lead occurs in small quantities as
a pulverulent mineral of a bright red colour, some-
times mixed with yellow. C/zlorz'de of lead occurs in
the Mendip Hills. The most important and abundant
ore is the salp/zm'el or paleaa, which crystallizes in
the cubic system, and is deposited on: a matrix of
quartz, carbonate of lime, finer-spar, or baryta. The
rich lead mines of the West of England occur in
clay-slate; those of Derbyshire and other northern
districts in limestone. Galena, when pure, is com-
posedof lead 86'55, and sulphur 1345. It nearly
always contains silver, whence the name argeali-
feroas galeaa applied to it. It is a valuable source of
silver in many parts of Europe and America.
Carbonate of Lead is found in acicular crystals, in
radiated and compact masses, in concretions and in
earthy deposits: it has a white colour, and except in
'1275 shows the form of

the earthy varieties, the peculiar lustre of white
lead. The crystallized specimens are sometimes black:
from the presence of sulphuret. A specimen from
Teesdale, analysed by Mr. J. A. Phillips, gave 83'55
of protoxide of lead, and 16'52 of carbonic acid.
This gentleman says :——-“ When abundant, the car-
bonate forms a most valuable ore of lead, and fre-
quently yields above 7 5 per cent. of that metal; but
from its dissimilarity to the other ores of lead it was
for a long time considered by miners to be of no
value; large quantities which had been formerly buried
in rubbish, are at the present time being excavated
and worked with great advantage in many of the
Spanishmines, as also at different points of the valley
of the Mississippi, in the United States of America.”1
Carbonate of lead, or while lead, PbO, C02, is ma—
nufactured in enormous quantities for the use of the
painter. When pure it is a soft white powder of great
density; it is insoluble in water, but readily dissolved
by dilute nitric or acetic acid. The manufacture of
white lead is for the most part conducted by the Dutch
process, which was introduced into England about
1780. In this process metallic lead is cast into the
form of stars or circular gratings, six or eight inches.
in diameter, and from Z‘- to ginch in thickness: 5 or 6
of these are put into an earthern pot shaped some-
thing like a flower-pot, and containing a little strong
acetic acid not in contact with the lead. The pots
are arranged side by. side on the floor of a brick
chamber, and are imbedded in a mixture of new and
spent tan. The pots are then covered with loose
planks, and a second range of pets is placed upon.
the former, and also imbedded in tan, and in this way
a stack is built up of eight or ten layers of pets to
the height of 25 feet. At Newcastle-upon-Tyne,
where white lead is extensively manufactured, a num-
ber of these stacks are arranged on each side of the
enclosed space, each stack containing about 12,000 of
the pots, and from 50 to 60 tons of lead. In France,
pits of masonry are constructed for the purpose, and
stable manure is the fer- Fig. 1275.
menti'ng material. Fig. m _ a
pot employed, l l being a
ledge for supporting the
lead 0 which is bent into
a coil 0'. The acid is con_
tained in a. The mouth
of the pot is also covered
over with strips or castings
of lead, as shown in the
figure, and then comes the plank m a, which serves,
as it were, for the ceiling of one layer of pets,
and the floor for another layer above it. Soon after
the stack is completed the tan begins to heat or fer-
ment, and the temperature of the interior rises to 140°,
150°, or higher. This causes the acetic acid slowly
to volatilize, and the vapour passing readily through
the gratings of the lead, acts as a sort of carrier
between the carbonic acid evolved from the tan
and the oxide of lead formed under the influence
(1) “ Manual of Metallurgy.” 1852.


1.18
of the ‘acid vapour” and the oxygen of _ ‘the air.
The quantity of acetic acid used in proportion to
the lead is. so trifling, that it can only in an indirect
manner lead to the production of the ‘carbonate.1 In
the first‘ place, an oxide is formed .on the. surface of
the lead, and with this a? portionof the acid vapour
unites, to: form a~- subac'etate. of lead. In the third
place, the carbonic acid liberated by. the fermenting
tan decomposes the subacetate'of lead, and converts
it into a carbonate. Fozzrflzly, the acetic acid thus
set free determines the formation’of' another portion
of sub-acetate, which becomes changed, in its turn,
into carbonate. Int-his ‘way the. action proceeds, until,
in thecourseof'from four to six weeks, the fermentation
of the .tan‘is at an end. The stack is then unpacked,
and the lead taken'out ; it retains the form in which
it was ‘cast, but has increased in size, and is converted
into. dense white carbonate. In some cases the con-
version is complete; inothers there is a central core
of metallic lead; these. variations depending upon the
position of the lead in the stack, as also upon the
season of the year, the temperature,. and the state of
the atmosphere. The factory is so arranged that the
stacks are in different states of progress at the same
time. The white castings of' lead are passed through
rollers, by which the carbonate is crushed and broken
up, and the central‘ core of Mac lead thus separated
from the Mafia. The latter is next ground up into
a thin paste, with water, and is then reduced, by
suecessive'washings and subsidences, to an impalpable
powder.. This is collected in earthen pans (each
holding lOEor 12 lbs‘), and arranged on iron shelves,
in=a room heated to‘ about 190°. When dry, it forms
an impalpable white powder, without any signs of
crystalline . structure, even when viewed under the
microscope.- In this beautiful and remarkable process
the texture and purity of the metallic lead are points
of importance.‘ .Rolled or sheet lead will not answer:
the. gratings, ..coils, stars, 8270. must be of cast lead.
The metal must also be pure ; for if it contain iron,
the white lead will be of a tawny hue, and if a trace
of silver be present, it becomes dingy under the action
of light.» ' " .
If the white leadproduced by the above process be
intended for the-‘use of the painter, it is mixed in a
vat, with; linseed oil, to the consistence of a'very stiff
paste, a mechanical stirrer being employed for the
purpose ; it-tis then ground between millstones, and is,
lastly, packed into casks for the market. 1 cwt. of
white lead requires about 8 lbs. of oil.
Other processes are adopted for the manufacture
of white: lead, which, however much they may difier
from the Dutch method, and from each other, are
very: similar .in principle, viz. the precipitation of
a soluble salt vof lead by means of an alkaline‘ car-
bonate, or. bycarbonic acid; as for example: when a
solution of nitrate or acetate of lead is decomposed by

"(1) Supposing 100 lbs. of real acetic acid to be present in‘ the
stack; this would contain about 47 or '48 lbs. of carbon, whereas
6, 74p lbs, are required ‘to furnish the carbonic acid required by the
50 tons of lead in the stack, ‘in order to convert it into a car-
bonate. ~ 1 I
- able to get rid of the crystalline character.


carbonate of soda,‘ a dense white precipitate is ob-
tained, which being washed and dried, is a pure white.
It is found, however, by the microscope to consist of
minutecrystalline grains, a circumstance which inter-
' feres so much with the 50:15] or opacity of this white
lead as to render ‘it comparatively useless as an oil
paint, no-grinding or mechanical comminution being
The
compound thus formed varies in texture according as
the carbonate of soda is added to the nitrate of lead,
or as .the nitrate to the carbonate, the latter mode
of precipitation furnishing a more impalpable powder
than the former; but the solutions require care in the
method of diluting. 2. The celebrated Olz'c/zy wlzz'z‘e
(made at Clichy, nearParis) is prepared as follows :-
A solution of litharge is made in acetic acid, in such a
way as to obtain a basic acetate, containing a large
quantity of oxide of lead. This is decomposed by car-
bonic acid obtained from the. combustion of a mixture
of coke- and chalk; and the air which is propelled
through the fire by means of a blowing machine is
conveyed by pipes into the solution of subacetate of
lead. The carbonic acid, which escapes abundantly
from the earth in some localities, is used for a similar
purpose. The oxide of lead is completely precipitated
in the state of carbonate, and the liquor contains the
whole of the acetic acid, which is used to dissolve a
fresh quantity of oxide of lead, and the new solution
is submitted a second time tothe action of carbonic
acid. Hence the same acetic acid may be used to
transforr‘n'an indefinite quantity of oxide of lead into
ceruse; but as a certain portion of the acetic acid
is dissipated in the course of the process, a small
portion is added at each operation. The apparatus
used in this process is shown in Section, Fig. 127’ 6.
v v is the vat in which is made the solution of
litharge in acetic acid, 8 being a stirrer for assisting
the operation. The solution is drawn 0E by a tap a
into a second vat, or underback, v’, {lined with
copper: here the‘ metallic lead, iron, copper, and a
little chloride of silver, and other insoluble matters
are deposited, and the clear liquor is decanted into
a close vessel jj, through the cover of which pass
about 800 tubes, dipping into the liquor, while
their upper extremities are connected with a wide
tube '10' 12 which is attached to the blowing appa-
ratus a is: this is supplied with_ carbonic acid from
the furnace n, which is charged with 1 measure of
coke mixed with 2% measures of ‘chalk in small frag-
ments. The carbonic acid escapes by the tube 2!.
At the end of 12. or let hours, when the precipitation
of the carbonate of lead is complete, the neutral ace-
tate is drawn ‘off into the underback b’, whence it is
forced by a pump e, along/a tube m 22, back again into
the vat v. The carbonate l of lead is drawn off into
the vat 6, and the series .of operations is then gone
through as before. 3. In Button and Dyer’s patent
process carbonic acid is passed through a hot solu-
tion of .subnitrate of lead, whereby carbonate of
lead ‘is precipitated, and the solution reverts to the
state'of neutral nitrate : this is converted again into
subnitrate; by boiling with powdered litharge, and the
LEAD; ‘ 1,19.
precipitation is repeated continuously. The carbonic ~proper consistence for the painter," the precipitated
acid is obtained by the combustion of coke, and the white lead requires 16 lbs. of oil per cwt. 4. Under
gas is purified from sulphurous acid and sulphuretted Torassa, Wood 85 Go.’s patent, granulated lead 'is
hydrogen, by passing it through a washing apparatus, agitated with water, by which a quantity of hydrated
containing chalk and white. lead diffused through oxide of lead is formed, and this is subjected to the
water. The precipitated carbonate of lead is Well action of carbonic acid. This plan has not succeeded.
washed, condensed into cakes, and dried in stoves. 5. In Gossage and Benson’s patent process, finely
One of the great objections to this, in common with powdered litharge is moistened, mixed with about
other precipitated white leads, is want of body; for Tg-gth part of acetate of lead, and submitted, during
while the white lead obtained by the Dutch process constant stirring, to acurrent of heated carbonic acid:
requires only 8 lbs. of oil per cwt., to bring it to the ; a subacetate of lead is successively formed and decom-

012 9&
4i
V
.l
I’ 7‘
_il N L c


.\
; 775 :1“ l "2.“ \\
ll _
fiu-l ' H
//









///' 5 - ‘ _, .
1 .rf/Wx/f
Fig. 1276. MANUFACTURE or cmcnY WHITE.
posed, so that only a small quantity of the original taken to prevent the powder from flying about. A
acetate is required. 6. In Hemming’s process, nitrate plan invented by MM. Hameline and Besancon for
of soda 1s distilled with the proper quantity of sul- rendering these operations less dangerous is described
phuric acid, by which nitric acid and sulphate of soda by M. Payen in his excellent “ Précis de Ghimie In-
are formed: oxide of lead is dissolved in the nitric dustrielle, 1851.” The dried cakes of ceruse are put
acid, and the sulphate is converted into carbonate of into a hopper 2', through which they fall upon an
soda, in the usual way, by heating with coal and chalk; endless band 6 ,- this conveys them into a mill, m m,
a solution of the carbonate of soda is then added to which reduces the ceruse to powder. This powder
the solution of nitrate of lead, producing carbonate of falls upon a sieve b 6, furnished with brush'es,‘moving
lead and nitrate of soda: this nitrate of soda is then upon the same axis a as the mill: the larger particles,
treated as before. which cannot pass through the meshes, escape by side
{7, g openings a into a close receiver: the powder which
/./ passes through the first sieve falls upon a second
a???‘ / 6' b’, and thence down an inclined plane into a vessel
s-
00', which may contain 011 if the ceruse‘ is to be
“s >\\_\ mixed therewith ; or it may be collected in this vessel
“1 in the state of a dry impalpable powder. The chamber
’ c, which surrounds the mills, has at its upper part a

z 1, . . . -
a pipe 19 openmg into a shaft 0, the draught of WhlOll'

r. w__ (2 l
g ' carries oii’ the dust from C; but a large portion of the



m "r ' . .
\r , powdered ceruse is condensed in the chamber 0 by
\_ .w means‘ of the jets of vsteam s, the condensation of
m 223 ' ' ‘

way of the chimney.
f /
/ / // / , '.
semen / am; leidffiuiafig. fififitfllifiihiifit;
5, 5 digesting the sample in dilute nitric acid, which
/ Z 6’ _ ‘in dissolves the carbonate of lead, but leaves the sulphate
5' of baryta. Venice white is a mixture of equal parts
0’ 4d a white lead and sulphate of baryta; Hamdu'rg ‘w/lz'le,
=~- '0 {*3 one part white lead and two parts sulphate of baryta;
-__-__
—__
_ Dutch wfiz'z‘e, one part white lead and three of the
sulphate; Krems or Kremnz'tz w/zz'te, Silver w/az'te, and
the Clzclzg/ wkzt‘e already noticed, are pure white lead.
Fig. 127?. nausea METHOD 0? cammxe CEBUSE. A minute addition of indigo 01, of lamp ‘black is some_
The grinding and sifting of white lead are very in- times added, to give a slight bluish shade to the
jurious to the health of the workpeople unless care be white lead.

which, precipitating the powder, prevents loss by'
120
LE Al) .
Snc'rron III.--—Trmonr AND Pnxcrron or Luan-
SMELTING.
The native sulphuret of lead, or galena, is the chief
source for supplying the commercial demand for lead
in this country. The ore, having been picked, is
broken and washed, for the purpose of separating‘
earthy and siliceous matters ; it is then roasted, at a
moderate heat, so that about one—half of it shall be
converted by the absorption of oxygen into sulphate
of lead, the heat being so regulated as not to drive off
any of the sulphuric acid. The sulphate thus formed
having been well mixed up with the unaltered portion
of the ore, the temperature is very rapidly increased,
so that the two shall be fiuxed together; the result of
which is the conversion of the mixture into sul-
phurous acid gas, which passes off to waste, and pure
metallic lead which is left behind. In this process the
sulphur of the unaltered ore combines with the sulphur
and oxygen of the portion which has been oxidized.1
The furnace in which these operations are carried
on is represented in vertical section and ground plan,
Figs. 1.278, 127 9. The sole is usually about 8feet long

‘I | .
,.-- s ' __"':‘ \\\\\§
’ -. _~“~ - ;_ f! ,
\\ \ ‘ ' ' - , Q‘. ‘I " ‘: . ‘\\:\l
“c _ ~._ ‘ I s.“ s _ _ \ 'r‘ F _. I
1‘ ‘I_ \\~ r gggsjssq
m’; ' ‘ \ \ Q \\
\ b
\








.\ sn-m \ \__ \\\E.\\
‘was: \~\y\\\\\\ -: \\' x Q; \~ \ \\' \: “\‘\_~ ‘\i ‘ §_\ \‘f
Fig. 1278.
and 6 feet wide, and is formed of the fused slags of
previous operations, worked to the proper form while
in a state of semi-fusion. About the centre of the
hearth is a depression for the fused metal to collect
in, and about this point is the tap-hole T, for drawing
off the metal into the cast-iron pan r, set in a niche a
little under the furnace side: 13‘ is the fire-place, B
the bridge, and o the chimney, which communicates


with fines leading into condensing chambers. The
arch of the furnace is about 14 inches above the top

(1) The whole process has been thus clearly represented by,
Fownes :-
Oxide oflead {{fgflgég'm- Free-
' Sulphur Lead ....... .. Free-
Sulphate of lead
Sulphuric acid
sulphuret cf'lead

of the fire-bridga'and at the'other extremity of the
hearth descends to within 6 inches of it, by which
means the flame is brought into close contact with the
charge. In the centre of the arch is an iron hopper H,
for letting in the charge. The door 1), for supplying
coals, is on what is called the “ labourer’s side ” of the
furnace; on the same side are three holes, 0 0, covered
with iron plates, which are removed when the charge
requires stirring or a supply of air. The opposite, or
“working side” of the furnace, has also three small
doors 0' 0', for working the charge or letting in The slag composing the sole is heaped up nearly to
the small door on the labourer’s side, and declines
to the other wall, so as to communicate with the
tap-hole.
The lead of one charge being drawn off, and the
slags cleared out, the trap or damper of the hopper is
withdrawn, and the whole of the charge let into the
furnace. In the North of England the weight of a
charge is about 12 cwt., and in Wales from 20 to 241
cwt. A labourer immediately spreads out the charge
with an iron rake; the doors and dampers communi-
cating with the fines are closed, but not sufficiently so
to prevent the entrance of air. Every now and then
the charge is stirred with an iron paddle, so as to
expose fresh surfaces to the air, and. during the ‘first
two hours very little fuel is added, the furnace retain-
ing sufficient heat from the previous charge; but after
this time some rich slags skimmed from the surface of
the lead in the lead pan are thrown in through the
doors furthest from the fire; the roasted oar is also
turned over, with a long iron paddle. The rich slag
soon gives up its metallic lead, and this is run out
through the tap-hole. The charge is worked over
with an iron paddle; the damper is raised alittle; and
as the temperature rises the fusing matters are brought
back by the smelter to that part of the sole which is
near the fire-bridge ; and his assistant, who always
works through the back doors, spreads them over the
surface with his paddle. Some quicklime is thrown
through the central opening upon the metallic lead,
which begins to collect on the depressed part of the
sole. After a short time the labourer again mixes up
the charge, while the smelter pushes the slags back to
= the fire-bridge; the doors are then left open, and the
slags begin again to flow back to the lower part of
the sole. At the end of 3 or 3% hours the damper is
opened to the full; fresh fuel is added ; all the doors
are closed, and the furnace is left for a hour. The
doors are then opened; the assistant stirs up the
charge, to assist the flow of metallic lead into the
depression, and, the smelter pushes back the slags.
More quicklime is added in order to liberate aportion
of oxide of lead, and also to make the slags less
liquid and more easy of removal. As the oxide is set
free it reacts on any undecomposed sulphuret which
escaped decomposition in the roasting. More fuel is
added to the grate, and a portion of powdered coal
A thrown into the furnace, to assist in the reduction of
the oxide ; the doors are again closed for 40 minutes,
at the expiration of which they are opened, and the
metallic lead allowed to flow out through the tap-hole. -
LEAID.
121
Some quicklime is 'addechin order to dry up the slags,
which are removed by the labourer.
Mr. Phillips states that at Holywell each ton of
ore smelted consumes 10 cwt. of coal; but at Grass—
ington in Yorkshire, where a more fusible galena is
employed, and more time allowed for the operation, '7 1f,-
cwt. of fuel are required per ton. The whole 8666/6 of
a furnace, including the time for casting the lead into
pigs, occupies from 5% to '7 hours. During this time
the frequent cooling of the furnace brings back the
fused materials to a pasty condition, which allows of
their being disintegrated by the action of the paddle,
and exposes a larger surface to the air of the furnace;
while the porosity of the mass allows streamlets of
metallic lead to trickle down to the internal reservoir
of the sole. The iron tools used in stirring up the
charge are rapidly attacked by the fused galena.
The lead thus obtained contains a sufficient per-
centage of silver to render its separation profitable.
Some ores, especially those of Spanish origin, contain
also antimony, tin, copper, and other impurities, which
must be separated before the lead can be treated for
the sake of its silver. For this purpose the lead is
fused in a furnace and exposed for many hours, and
in some cases for 8 or 4- weeks, to oxidizing influences,
by which means the antimony, tin, and other metals,
as also a portion of the lead, become oxidized, and
are gradually removed from the surface by an iron
rake, so as frequently to expose a fresh surface to the
action of the gases of the furnace, until most of the
impurity is removed, and a nearly pure alloy of lead
and silver is obtained. The silver was formerly
separated from the lead by the process of czrpellatiorz,
similar in principle, but on a much larger scale, to
that explained under ASSAYING; but of late years
Pattinson’s process has been in the first instance
adopted, as explained in our In'rnonucronr EssAY,
p. xcix. By this process the original lead, containing
about 10 ounces to the ton, is concentrated to about
300 ounces to the ton, while the desilvered lead does
not contain more than 10 dwts. of silver to the ton.
The silver is then extracted from the rich lead in a
cupel-furnace called a refinery. Pattinson’s process is
so simple and economical in its action that the
produce of silver in the United Kingdom has been
more than doubled within the last 20 years. Large
quantities of lead are also brought to England for the
purpose of being desilvered by this process, which is
now followed in most of the lead-mining districts of
this country.
Fig. 1280, is a plan of the refinery in which the
lead is separated from the silver. 1‘ is the fire-place,
B the fire-bridge; the flame and heated air pass di-
rectly over the surface of the cupel c, and thence escape
through the two openings 0 0 into the flue J’, which is
connected with the main chimney. There is a small
hood and chimney shown at 6, for carrying off the
injurious fumes of lead generated during the operation.
The cupel or test is an oval iron frame, of which the
greater diameter is ‘1 feet, and the lesser 2% feet : it
is surrounded by a ring 4: inches deep, and strength.
ened by cross bars. It is filledwith finely powdered

bone-ash, slightly moistened with a weak solution of
pearlash, which helps to give consistency to the bone—
ash when heated. The bone-ash is well beaten down
with iron rammers, and when the ring has been well
filled the centre is scooped out with a small trowel,
leaving a raised border of bone-ash all round as shown
in the figure : at the fore part or breast, the width of
a .2.






ens:
" _ $551215
%/%%iur%%////%//6ian " -
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k


Fig. 1280.
this border 1s 5 incnes, and at this point a hole is cut
for the escape of the fluid litharge, for it is not in‘
this large operation absorbed by the substance of the
cupel, as in the delicate and exact operation of assay-
ing. WVhen the test is properly prepared it is lifted
into the refinery, and wedged to its proper height
against a fixed iron ring or commas-6dr. The heat is
applied with great caution, to prevent the test from-
splitting, and as soon as it is perfectly dry it is raised
to a cherry-red heat, and filled through a spout with
the rich lead previously fused in the cast-iron pot
I, which has a small fire beneath it. The lead soon
becomes covered with a greyish dross, but on increas
ing the heat, a covering of litharge begins to form.
The blowing apparatus is now set in motion, and the
blast from the tuyere 2‘ drives the litharge from the.
back of the cupel up to the breast, and over the gate-
way, when it falls through the hole in the cupel into
an iron pot below. The blast not only sweeps off the
litharge from the surface of the‘ lead, but supplies;
the oxygen required for its formation. As the lead-
wastes away by the removal of the litharge, more
metal is added from the melting up, and the process
is continued until about 5 tons of rich lead have been
poured into the test. When this has taken place the
whole of the silver is left in the cupel in combination
with only 2 or 3 cwt. of lead. This is now drawn off
and another charge introduced, and when a suflicient
weight of this rich lead has been collected to yield a
cake of silver of from 8,000 to 5,000 ounces, the lead
is again melted down, placed in a cupel, and the pure
silver extracted. The test used for this purpose is so
hollowed out as to produce a thick plate of silver, and
allow space for the removal of the slags around its
edges at the completion of the operation. When the
last traces of the combined lead separate, the silver
Zz'gkieizs as in the small cupel,1 and very beautiful

(1) This phenemenon, as displayed in the small cupel, is very
well described by Aikin, and is quoted in ASSAYING. The French
chemists call it l’éclair. Regnault admirably describes it on the
large scale in the third volume of his Cow's de Chimie. He says :—
“ The moment when the oxidation of the lead ceases, and when
consequently the cupellation is finished, is marked by a peculiar
appearance called the lightening. During the whole period of
oxidation the metallic bath appears more brilliant than the walls-
of the furnace. Its temperature is, in fact, higher; for not only
does it share in the heat of the furnace, but its tcmperature_is_
122
LEADI
arborescent forms are produced 'on the surface of ‘the
plate. When very rich lead is operated on, the plate
of silver may be worked off at once from the refinery.
The litharge produced during the operation, as also
the cupel bottoms, contain silver, and these are
operated on for the recovery. of that metal.
By the improved methods of enriching and refining,
lead containing only 3 ounces of silver to the ton may
be advantageously treated for its silver: whereas
formerly, from 9 .to 11 oz. of silver per ton. were
required ‘tel-make the ,operation- profitable, and then
thegwhole of the associated‘lead-had to be converted
into. litharge, and this had to be again reduced at
great expense of labour and fuel, in order to recover
the‘rnetallic lead. If tin or antimony were present
in the5 argentiferous .galena, the difficulties were of
course increased.
' The litharge from the refinery, the pot dross and
the mixed metallic oxides from the calcining pans, are
treated for the recovery of the metallic lead, in a
reverberatory furnace similar in form but smaller in
dimensions to the smelting furnace; the sole is also
differently arranged, for it is made to slope gradually
from the fire-bridge to the flue, where there is a de-
pression and a tap hole, which is left constantly open
for the lead as it is reduced to flow out into an iron
basin placed for the purpose, and from which it is
laded into moulds, which bear the name of the smelting
company by which'it has been prepared. The litharge
is mixed with small coal, and the sole is also covered
with a layer of bituminous coal, which with the aid of
the reducing gases effect the reduction of the htharge.
A furnace of this kind, with a sole 6 feet by 5, will
from ordinary litharge afford about 3% tons of lead in
241 hours.
‘ THE SCOTCH FURNACE. In Durham, Cumberland
and Northuinberland, the ores of lead are smelted in
what is‘ called a Seozfcfifwvzaee or ore-lzem'flz. It is of
very simple construction, consisting of a rectangular
- cavity of masonry 0,
Figs. 1281, 1282, lined
with cast-iron.‘ The
sole-plate s is also of
cast-iron, and has an
upright ledge at its back
and two sides. In front
m3“ \. __. .__

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\\\\_,§\;l;\\;k\\\\\ kg‘;- of the hearth 1s another
- §I\§Sk\\\wmkm cast iron late 20 called
\ _, C "'
P "
. . \\ \\ \ ‘Q the work-stone, also sur-
Fig. 1281. rounded with a ledge
except towards the sole, but it often happens that the
sole-plate and the work-stone are formed of one cast-
also raised by the heat which is disengaged by the chemical com-
bination of ‘the lead with the oxygen. When, however, the lead is
completely. oxidized, this second source of heat no longer exists;
the‘- disk- of metallic silver quickly sinks down to the temperature
of the furnace, and‘instead of being brilliant as it was before, it
becomes'dull. 0n‘ the other hand, at the moment when the last
traces‘ of lead oxidize, there is on the surface of the metallic bath
only a-pe'llicle of fused litharge; this quickly becomes thinner and
thinner, andpresents'in rapid succession the colours of thin plates
dror the soap-bubble, then becomes torn up like a veil, and discloses
the surface~ of the metal. It is this rapid succession of optical
phenomena to ‘which the name of l’éclair or the lightening‘ is
applied.” ~


' ing.' The platehas a slope from behind forwards, and
its hinder ledge is .about 4%,..— inches above the surface
of the hearth, and in some cases is separated there-
from by a cavity into which is rammed a wet mixture
of powdered bone-ash and galena; the melted lead
cannot penetrate this, but after filling the basin formed
by the raised ledge at the bottom of the furnace, flows
out by the gutters g in the work-stone, and is received
into a melting pct 12, placed below the front edge
of the work- '
stone. The
hinder ledge
of the sole is
surmounted
by a piece
of cast-iron,



§lséiftliétalh
swirl .
\ strewn
\\ \



ll 1-
z






called the Meir-slam, on " l '
which the Fig. 1282.
tuyere t, is placed. This supports another piece of
cast-iron called the pipe-stone, scooped out in its
under part for the passage of the tuyere. This
piece advances 2 inches into the furnace, the back
wall of which is crowned by another piece of cast-
iron, also called the back-stone. On the ledges of
the two sides of the sole are two bearers of cast-iron
advancing an inch or two above the hinder edge of
the work-stone; above these, at the height of 5 inches,
and 12 inches from the back of the hearth, is another
bar of cast-iron, resting on fire bricks, called the fore-
storze. The space at each end of the fore-stone is
closed by a cube of cast-iron, measuring 6 inches on
the side, called a key-stone : two others are also used
for filling up the space between the fore-stone and
the back part of the furnace. The front of the
furnace ‘is open for about 12 inches from the lower
part of the front cross-piece or fore-stone up to the
upper part of the work—stone, and through this open-
ing‘ the smelter operates. The escape of fumes into
the‘ smelting house is prevented by enclosing the entire
hearth in a hood of arched masonry or brickwork,
which is bound together by heavy iron straps, passing
beneath the" foundation of the hearth, and kept in
place by screw-bolts. '
'Before the galena or other ore is smelted in this
furnace, it is first roasted on a long flat hearth covered
by a low arch, and heated by a fire-place at one end.
From 9 to 11 cwt. of ore form a charge, and from 212—
to 3 hours are required for the roasting. The tem-
perature is kept below the melting point of galena,
and the object of the operation is partially to oxidize
and to get rid of sulphur. Copious fumes of sul-
phurous acid escape from the surface, thus getting
rid of a portion of the sulphur, antimony, &c., and
should any portion approach the fusing point and
become clammy,~ a fresh surface is exposed to the air.
In this way the slime ores and other friable matters
are so' far ‘agglutinated as not to be liable to be
carried off by the blast in the smelting furnace.
After each shift‘in the smelting furnace, there is
left on the hearth a portion of ore which has been
only partially reduced. This is called browse: it is
LEAD;
.123:
mixed with fragments'of ‘coke and clinkers, and is
used in the next charge. At every new shift the
cavity of the. furnace is filled up ,with rectangular
blocks of peat built up in a wall towards the front.
An ignited ‘peat- thrown before the tuyere t, the
blast being on, soon ignites the whole. Aiittle coal
is next thrown on, and then a quantity of the browse.
After this most of the matters contained in the
furnace are drawn over on the work-stone by means
of a large rake: the refuse of the ore, called grey-slag,
which has amore shining appearance than the browse,
is taken off with a shovel, and thrown outside the fur-
nace to the right. The browse left on the work-stone
is now thrown into the furnace with the addition of
a little coal. A peat is put before the nozzle of the
blast to prevent it from becoming stopped up, and
also to divide and diffuse the blast. If the browse
be not well cleansed from the slag, which is known by
its soft state and tendency to fuse, a little quick lime
is thrown in, which dries up the materials, and allows
the earthy parts to form into lumps or balls; so also
if the ore be refractory from the presence of silica,
alumina or iron, lime is added to make them more
fusible. The lumps of grey-slag contain from 313th to
313th of the lead which was present in the ore : these
are afterwards smelted in the slag hearth at a higher
temperature. When the browse has been thrown
back into the furnace, a little of the ore is strewed
over it. After 10 or 15 minutes the materials in the
furnace are again drawn upon the work-stone, the
grey-slag is removed by the rake, and a portion of
metallic lead is carried off by the channels into the
pan. Another peat is then placed before the tuyere,
coal and quicklime are introduced in suitable propor-
tions ; the browse is thrown back into the furnace
with a fresh portion of ore upon it, and another
interval of 10 or 15 minutes is allowed, when the
slag is again separated and another portion of metallic
lead escapes into the pan. This method of working
is continued for 14 or 15 hours, forming a melting
slzgfl, during which from 20 to 40 wt of lead, and
even more, are produced. This lead is much purer
than that produced by the smelting furnace, because,
on account of the comparatively low temperature
employed, the lead and the silver only are sweated
out, the other metals not being reduced.
The slags which are sufficiently rich to go through
a distinct process for the recovery of the lead are
treated in a slag furnace, the construction of which
is very much like that represented in our INTRO-
nuc'ronr ESSAY, Figs. LL, LIL, 1.111., and corresponding
with the fomvzeau d mrmcfie (elbow-furnace) of the
French, and the Im'ammq/"ezz (crooked furnace) of the
Germans. This furnace has the form of a rectangular
prism, 26 inches in length, 22 in breadth, and 33 in
height. The bottom is composed of a cast-iron plate,
slightly inclining from the side of the tuyere towards
the front of the furnace. On each side of the bottom
plate are bearers, as in the ore-hearth, supporting the
fire-hearth, which consists of 2 stout plates of cast-
iron, about 12 inches broad and 26 long. A space of
about 5 inches is thus left between these front stones _

and the bottom ‘of the furnace, and" an'extra- height of
2% inches is gained by placing between them a row of
fire-bricks. The slags which escape through the
opening at the breast pass over the surface of a pot,
and are then received into a ‘large iron cistern sunk
in the‘ earth, through ‘which cold water is constantly
flowing. This makes the liquid slags fly to pieces,
and adapts them to the subsequent operation of
washing.
In working this furnace the bottom is covered to
the height of 15 inches with small spongy 'cinders
beaten closely together : the pot for the reception of
the lead is also filled with them. The rectangular
space is then filled with peats and ignited under the
influence of the blast: a layer of coke is next thrown
on, and when the temperature is high enough a layer
of grey slag or other scoriae is introduced. Alternate
layers of .coke and slag are thrown in from time to
time, and the slag and the lead being. made perfectly
fluid, the metal filters through the bed of peat-Cinders,
while the slag being by its viscidity retained above
them, the lead is thus separated. When the coke
bed becomes covered with fluid slag, the workman
perforates it with a bent iron rod, and the liquid
silicates run off by this orifice, and after passing over
the surface of the pot for the reception of the lead
are received into the water cistern.
The lead obtained by this process is, on account of
the high temperature employed, of inferior quality 5
it is therefore not adopted for ores which admit of
being economically worked at the smelting furnace or
at the ore-hearth. The slag-hearth is, however, used
for those ores whichyield only a small per-centage of
metal, and also for some of the foreign carbonates,’ in
which the object is rather to extract the silver than
economise the lead.
In all smelting establishments there is some dif-
ficulty in preventing a considerable portion of lead
from being carried off in the form of fame, in con-
sequence of the ease with which lead sublimes at a
high temperature. This not only occasions loss to
the smelter both in lead and silver, but is also very
injurious to the vegetation and cattle of the sur-
rounding district. In order to prevent the dispersion
of the lead fume, the fines of the various furnaces are
at some works contrived so as to communicate with
large chambers in which cold water is made toshower
down from the roof. The gases from) the fines are
also in some places drawn through cold water in.
order to separate ingredients which are of value if
preserved, but highly noxious if dispersed through the
air in their elastic form. Unfortunately, ‘the arrange-
ments required for working these contrivances are
costly and not always ,successful. A model of the
condensing apparatus used at the Duke of Buccleuch’s
works, at Wanlock Lead-hills, in Dumfriesshire, was
exhibited in the Great Exhibition. An oblong build-
ing in solid masonry about 30 feet in height is divided
by a partition wall into two chambers; adjoining
these and communicating with one of them at the
bottom is a tall chimney or tower. The smoke from
the various furnaces, of which there are 8, situated
124_
LEAD.
about 100 yards from the condenser, is carried by
separate flues into a large chamber; from thence by
a larger chamber it enters the bottom of the first
chamber of the condenser, and is forced upwards in a
zigzag course towards the top, passing 4: times
through a shower of water which is constantly falling
from a pierced reservoir at the summit of the tower.
The‘smokethen passes through a cubic space‘filled
with coke, through which a stream of water filters
downwards. The smoke having reached the top
passes into an exhausting chamber, which is about 5
feet by 7, and upwards of 30 feet high. Above this
is a large reservoir'well supplied with water; it has
an iron bottom, in which are 12 slots or openings
about an inch wide, extending across the reservoir,
and communicating directly with the chamber beneath.
On this iron plate works a hydraulic slide plate, with
openings corresponding in one position with those in
the reservoir. This plate receives a horizontal reci-
procating motion from a water-wheel or other power
driven by a connecting-rod and crank. In the middle
of every stroke the openings in the plate correspond
with those in the bottom of the reservoir, and a heavy
shower falls through the vacuum chamber sweeping
the enclosed space, and carrying with it the matters
suspended in the vapours of the furnaces. The water
saturated with particles of lead, &c.,held in mechanical
solution, is passed into large dykes or reservoirs, where
it deposits its metal. The specimens of fume exhi-
bited, were said to contain about 33 per cent. of pure
lead, and about at oz. 17 dwts. and '7 grains of silver
to the ten.
The satisfactory results of the above arrangement
are stated at page 0. of our Introductory Essay. In
some other districts the condensing apparatus does
not perform its work satisfactorily, or there is even
no attempt made at condensation. In a paper by Dr.
George Wilson, read to the Royal Society of Edin-
burgh, and contained in the Monthly Journal of
Medical Science for May 1852, the writer states that
within the short space of five months in 1851, he had to
make a series of analyses in connexion with the death
of 13 horses, which together with several cows, were
supposed to have been poisoned by compounds of
lead transferred by the atmosphere or by water to the
fields in which they were pastured. The herbage of
these fields was found to be impregnated with
carbonate of lead, and in two of the cases, the water
which the animals drank proceeded from the mine
and was employed in washing the ore : this also con-
tained carbonate of lead. On analysis, lead was
found in several organs of the body, especially in the
spleen, and Dr. Wilson remarks, that this is probably
the most convenient organ for analysis. “ Its small
size, its loose spongy texture, and its comparative‘
freedom from fatty matter, enable it to be rapidly and
satisfactorily examined. In many cases, if lead were
found in the spleen, it would not be necessary to
seek for it elsewhere.” -
In the German method of smelting the fume is
condensed by making the smoke pass through a series
of chambers before‘it escapes intothe air. The general

arrangements of the smelting hearth in Germany ‘and
some other parts of Europe are different from those
adopted in this country. With poor ores and a
siliceous gangue the method applied to moderately
rich galenas would entail the loss of a great deal of
lead in the form of oxide, which would not react upon
the undecomposed sulphuret, but would combine with
the silica to form a vitreous slag very diiiicult to
reduce. Metallic iron is, therefore, employed to
reduce the sulphurets of lead: the iron combines
with the sulphur of the lead, forming a fusible
sulphuret of iron, and the lead is set free. For an
account of the processes connected with this opera-
tion, We must refer to Itegnault’s “ Cours de Chimie,”
tome 3me, or to Phillips’s Manual of Metallurgy.
Snc'rron V.—MANUFACTURES IN LEAD.
The chief applications of metallic lead in the arts
are in the form of sheets for covering roofs and pipes
for conveying water. It is also used in certain alloys,
such as lype-melal, solder, 85c. [see ALLOYJ and also in
the manufacture of slwl.
S/zeel-leacl—The manufacture of sheet-lead by the
old method, is conducted much in the same way as
plate-glass is cast, only more roughly. [See GLAss]
A stout table or bench 15 or 20 feet long, and 5 feet
wide, with a raised margin, is covered with fine river
sand. The melted lead is ladled into an oblong trough,
suspended over the table, and this is then upset upon
the sand. Two men then place a wooden strike,
Fig. 1283, across the table, and resting the parts 6 6
upon the raised edges, pass it quickly along by the



handles a a, thereby spreading out and driving for-
ward the molten metal, by means of the edge cc,
leaving behind them a plate of tolerably uniform
thickness, to cool upon the sand, the overplus of lead
flowing ed at the foot of the table into a box. Lead
produced in this way is considered to be less liable to
contraction and expansion, and consequent fracture
from change of temperature, than sheet-lead prepared
by milling or rolling. This is prepared in the follow-
ing manner :——the metal is first cast in an iron frame;
into a plate from 6 to 7 feet square, and 6 inches
thick. It is lifted by a crane upon the rolling-mill,‘
which is a long frame or bench, 8 feet wide, and from
'76 to- 80' feet long. At intervals of a foot, and on the
same level are wooden rollers r '1', Fig. 1824, to allow
of the easy motion of the heavy sheet of lead L.
The laminating apparatus is in the centre of the
frame. It consists of two heavy cylinders, the upper
of which, 0, is seen in the figure. These cylinders
are each 16 inches in diameter: they are turned as
truly as possible, and the distance between them is
regulated by means of the screws 8, by turning the
disc (l, which is furnished with a graduated plate and
pointer. There is also an arrangement for reversing
the motion of_ the rollers.
The plate of‘ lead, cast as. before described, is .
LEAD—LEATHER.
125'
passed between the rollers, by which it is strongly
compressed and elongated; the distance between the



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' I \ _

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Fig. 128%. ROLLING MILL.
rollers is then diminished, the motion of the mill is
reversed, and the sheet is again passed through.
“Then the lead escapes from the grip of the rollers, it
is again passed between them by two men standing
one on each side of the frame, and with a crow-bar
pressed against the edge of the lead, and the pins p
as a fulcrum, the lead is again pressed into the grip
of the rollers, the motion of which is reversed at each
passage. This operation is repeated anumber of times,‘.
passing backwards and forwards through the rollers
until it is greatly diminished in thickness, and increased
in length. WV hen the length becomes too great to
manage conveniently, the plate is cut into two parts,
and each part is milled separately. The lead may
have to pass 200 or 300 times between the rollers,
whereby the original length of 6 or '7 feet may be in-
creased to about 400, the breadth being '7 feet.
This is cut up into shorter lengths, and made up into
a roll for the use of the plumber, who designates
sheet lead by terms indicative of the weight of a
square foot - as 5, 5g, 6, 6}, ‘.7, ‘7%, 8, 8,-',-lbs.
Leadpz'pa—This is formed by casting a short but
very thick plug or cylinder of lead, with a bore in the
centre of the exact size required. The plug is then
put upon a long steel mandril of the size of the bore,
and passed between rollers with grooves of different
sizes, according to the external diameter required; or
the plug may be drawn through metal worfles or
collars of different sizes, each succeeding hole being
less than the former, until the pipe is extended to the
length and thickness required. By this method the
lead is compressed and rendered more durable. A
bright smooth surface is given to the pipe by passing
it once or twice through a cutting die, which shaves
off a thin film of the metal. The pipe is dragged
through the holes in the collars by means of an
endless chain, passing round two wheels or rollers
set in motion by steam-power.
The only objection to this method is the limited
length of the pipes so produced, 20 or 30 feet being

the greatest. ' When a very long pipe'wit'hout oints
is required, the hydrostatic pipe-press is used. This
consists 'of an ordinary hydrostatic press, situated
below the floor of the workshop : above this is a cylin-_
drical reservoir 1t,'l*‘ig. 1285, for the reception of the
fluid metal: this is surrounded by an annular fire-
place F, which is filled with live coals, and provided
with a chimney for carrying off the smoke. At the
upper extremity of R, a steel die is fixed, of the
diameter required for the outside of the pipe: through
the centre of this die passes a mandril of the size re—
quired for the bore. The reservoir in is filled with
melted lead through the spouts, which is then removed
and the aperture stopped with a stout iron plug. The
hydrostatic press being then set in action, the piston
r, attached to the top of the ram, is slowly driven
upwards into the reservoir a, driving the melted lead
before it. The lead in escaping is thus forced through
the annular space between the mandril and the fixed
collar, by which means a perfectly finished pipe is.
formed, and as it escapes it is coiled round the drum
1). In this way pipes of very great lengths may be
formed.




Fig. 1285. .
8 . . 4pm‘
.I I, - f‘ $-
,— Iihffiliia'l t. pig; s


LEATHER is a chemical combination of skin with
the astringent vegetable principle called {cumin or
Mimic acid. The manufacture in Great Britain ranks
next in importance to that of cotton and of wool, and
is probably equal to that of iron. There is a large
and constant demand for leather as an article of
clothing: it enters into the construction of various
engines and machines; supplies harness to our horses,
linings to our carriages, and covers to our books;
For all the varied purposes to which leather is
applied it is well adapted, and it was probably at the
earliest period of man’s history that an art so neces-
sary to his comfort and welfare became known. The
I26
. LEATHER.
skins of - animals taken in the chase are in their fresh '
state tough, flexible, and elastic, and seem, at first
view, to' be well adapted for clothing; but in drying
they ‘shrink, become Ihorny, pervious. to waer, and,
on exposure to- moisture, putrid and offensive. But
if the skin be separated from fleshy and fatty matters,
and then be put into a solution of certain vegetables
containing tannin, which abound in almost every
countr'y,:the skin separates the whole of the tannin
from the liquid, and becomes hard, insoluble'in water,
almost impenetrable by it, and incapable of putre—
faction. The subsequent operation of currying
renders it pliable and more waterproof. Similar
but less decided changes are produced upon the skin
by impregnating-‘it with alum, and also with oil or
grease. The object of these processes being to render
soft and flexible that which would otherwise be hard
and unyielding, the skin thus transformed was called by
our Saxon ancestors lz'llz, lllfie, or Milan—that is, soft,
or yielding; whence our term, leather. The word law,
and the French tamer, are from the Low Latin, lanai-e.
SECTION I.-—Tn:n Skins USED IN PREPARING
LEATHER.
The hide or skin of an animal consists of three
distinct parts, viz.—the epidermis or cuticle, which is
covered with hair or wool; below this is the l'elz'ezl-
laled or reel-like tissue; and, thirdly, the dermis,
cerium, calls, or true skin, which is in contact with
the flesh. This last is the only part which can be
tanned; so that it is necessary to get rid of the two
former before the conversion into leather can be com-
menced. The true‘ ‘skin a thick, dense, hard
membrane, composed of fibres interlacing each other
in a curious complex manner, and more thickly
woven towards the surface than below it: it is not
equally thick throughout, for those parts which cover
the mane, the back, and the ‘rump, are much thicker
than the parts which cover the belly. The dermis is
also pervaded by a large number of minute conical
channels, the small extremities “of which-terminate at
the exterior surface of the skin: [these channels,
which are placed obliquely, contain nerves, secretory
vessels, and cellular membrane. A fresh skin, from
which the fat and cellular tissue has been separated
on the internal or flesh side", and the epidermis and
mucous membrane from the external or hair side,
contains about 43 per C€11l3."0f solid matter, the re-
mainder being water. By digesting the true skin in
boiling‘ water, it becomes altered in its properties;
it is nearly all dissolved, and, by slow evaporation,
leaves a residue of gelalz'eze or glae. It is stated by
some chemists, that skin, membrane, 820. do not con-
tain gelatine ready formed; that this substance does
not exist, in the animal kingdom, but that it is gene-
rated byfthe action of hot water upon certain animal
substances. Whether this be the case or not, chemists
are agreed. in applying the term gelatinous lz'sszles to
all “those. ‘animal tissues which produce gelatine by
the action/of boiling water. At the ordinary tem-
perature, these tissues are converted into gelatine by
the-action of dilute acids and alkalis.

‘Notwithstanding the vast ‘consumption of animal
food in Great Britain, the skins of the slaughtered
animals by no means suflice to supply the demands
of the tanner. Large quantities of skins are im-
ported from various parts of the world, a short notice
of which may be of interest in this place.
All tanned leather is classed under the denomina—
tions of HIDES, Kins, and SKINS. From these there
are various kinds of
leather tanned "in Eng-
land: 1st. Bulls and
lac/m.- these are se-
lected from the stout-
est and heaviest ox-
hides. The butt is
formed by cutting off
the skin of the head
for glue; also the
checks, the shoulder,
and a strip of the
belly on each side. i
In the lac/e, the Fin-1286-
cheeks' and belly are cut off, but the shoulder is‘
retained. 2d. Hides consist of cow-hides, or the
lighter ox-hides; they are the same as lulz’s with the



lit. .
ill " .
1
i'








amt-i "a ‘will?’ iii.‘ '1
'; . lnl lllll
-'..- .slioUl-DER'
. till‘
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‘tgv-J


.YY ~~-_-—.
.: —~='—_—~—7_- n
bellies on. Hides are sometimes tanned whole, and
are struck for sole leather, in which case they are
called erop-lzz'dea. 3d. Sll'lflé' .- these are used for all
the lighter kinds of leather.
The hides of South America are in high repute;
they are the produce of the half-wild cattle which
pasture on the wide plains between Buenos Ayres
and the Andes. Hides are also imported from various
parts of Europe, as also from Morocco, the Cape of
Good Hope, and other places. They are imported
dry or .s'all‘ed.1
The ball or baa/r of the ox-hide forms the stoutest
and heaviest leather, such as is used for the soles of
boots and shoes, for most parts of harness and sad-
dlery, for leather trunks and buckets, hose for fire-
engines, pumpwalves, soldiers’ belts, and gloves for
cavalry. Formerly, when the use of metallic armour
was on the decline, its place was supplied by a very
‘ thick, pliant leather, made from the hide of the urns,
or wild-bull of the. forests of Poland, Hungary, and
some parts of Russia. This animal was commonly
called the big/fie, whence originated the term lief-leather.-
The Russian Company chartered by Henry VIII.
was compelled to import a certain number of bufi’e‘
hides, to be manufactured for military purposes.
Real half-leather was pistol-proof, and would turn
the edge of a sword. During the wars of Charles I.’s
reign, it was in great request, but it afterwards de-
c'lined. The hides of the real buffalo of Italy were
also imported for the same purpose. The modern
buff-leather is made from cow-hide, and is used for
little else than soldiers’ belts.
(1) The following were the imports into the United Kingdom
for the years 1850 and 1851.:—

Riz'er Plate 5' Rio Gf'ande. East I qzdz'a H orse- _
Dry. Salted. K ips. Hides.
1850 ............29,820 630,400 1,606,380 231,510
1851 .......'.....62,640 749,540 2,262,700 140,640 .
LEATHER.
127
Bull-ladle is thicker, stronger, and coarser in its
grain than cow—hide. The hide of the Zzulloak is in-
termediate between the two. 0aZves’-s/cz'n is thinner
than cows’, but thicker than most other skins.
It is tanned for the bookbinder ; but the greater
part of the supply is tanned and curried for the upper
part of shoes and boots. .
Sheep-skies are supplied chiefly by the home
markets, but many thousands are imported from the
Cape of Good Hope, and are considered to be supe-
rior to those of English growth: they are distin-
guished by the greater width of the skin that covers
the tail. They are simply tanned, and employed for
various purposes for which a thin, cheap leather is
required; such as for common bookbinding, leather-
ing for common bellows, whip-lashes, bags, aprons, &c.
Sheep-skins also form the cheaper kinds of. wash-
leather for breeches, gloves, and under-Waistcoats; as
also ‘coloured and dyed leathers, and mock-morocco,
used for women’s shoes, for covering writing-tables,
stools, chairs and sofas, lining carriages, &c.
Lame-slams are chiefly of home produce; they are
also imported from the north of Italy, Sicily, and
Spain. They are dressed white or coloured for
gloves.
The skins of goats and kids form the best kinds of
light leather. The chief supply of the best kid-skins
is from Switzerland and Tuscany, whence they are
shipped, chiefly at Leghorn. Goat-slams are princi-
pally obtained from the coast of Barbary and the
Cape of Good Hope. They form the best dyed
morocco of all colours. Kid-skins supply the finest
white and coloured leather for gloves and ladies’
shoes.
Deer-skins are, to some extent, supplied by our
parks; but the chief supply is from New York and
New Orleans; a few are sent from Canada, and some
from India. Antelope-skins from the Cape of Good
Hope are of good quality. Deer-skins are all
slzamoyed, or dressed in oil, chiefly for riding-breeches.
Shamoyed leather, of sheep, goat, and deer-skins,
was formerly a lucrative branch of the leather trade
of this country. This kind of leather was employed
chiefly for‘ breeches, white or dyed, worn by persons
who rode much on horseback. The English shamoyed
leather was so much esteemed, that it was not only
worn by our own cavalr , but by that of Prussia,
Austria, and most of the German states. During the
Peninsular war, however, it was noticed by the
British commander that in wet weather the leathern
garments fitted close to the skin, and were long in
drying, so that the men were liable to colds, rheu-
matism, and other complaints arising from this cause.
Woollen cloth was therefore substituted, and the
example being speedily followed by Austria and
Prussia, this branch of the leather trade speedily
declined.
Horse-[aide is tanned and curried for harness work,
for collars, &c. It has of late years been substituted
for seal-slain, but does not produce so good a leather.
Enamelled horse-hide, split or shaved thin, is used for
ladies’ shoes, in imitation of seal.

‘Dog-slain is thin, but tough, and makes good
leather. The supply is limited to this country, but
has fallen off of late years; horse-leather taking‘its
place for thin dress-shoes. But most of the clog-slain
gloves, as they are called, are really made of lamb-
skin. Seal-s/rz'n makes a valuable leather, but a large
proportion of the supply of seal-skins is used as fur
for covering caps.
Hog-skin affords a thin, porous leather, which is
usedfor covering the seats of saddles. The common
custom of cooking pork with the skin on greatly
limits the supply, which is chiefly from Scotland and
Yorkshire.J

(I) The following selection from the “Prices Current," con-
tained in the circular of Messrs. W. T. Goad 8a Rigg, of Mark
Lane, forms a good illustration of the extent and variety of the
trade in hides and skins :-
Ox AND Cow-Hines.
Buenos Agnes and M om‘e Video :- Prices
Dry- Weight. Duly fiee'
Best heavy ............. .. 29-32 lbs. at per lb. 6%-
Common ditto ........ .. 30-34 ,, ‘lg-5;,-
Best light . 21_24 ,, 53-6
Bulls .................... .. 38-42 ,, 4 -4%
Salted-Heavy ox 3é-4
Rio Grande and Rio J aneiro :—
Dry-
Best heavy............... 32-34 ,, 5 -5<zl~
2d 20—30 ,, ‘is-5
Salted-Cow............................................ 3 ——3k
Valparaiso, Lima, Puma, Arenas, 870. :-
Dry-1stsort............... 24-30 ,, 5i-53
Brazil:-
Dry .. . 3§-4
Wet Salted .. . 22-3};
Cape:—
Salted heavy................... .. 3 —3§
Kips and Skins . 4 -5%
New South Wales:—
Salted 25-22--
North American :-
Salted 25-22%
West India :——- .
Zé-lié
East India :—
Dry Salted 3 -8%,-
3§-7'§
Buffaloes 25-4,}
House-Hines.
Buenos Ayres :-
Salted...................... per hide 4s.—6s.
Rio ,, ’ 43. ~58.
German-dry ................................. . . , , 4s.—5s.
,, 4s.-5s.
KIPs—Dry. d.
Buenos Ay'res..................... per 1b. 7 -7%
African ,, 3 —&
.Petersburg, 8- 9 lbs. ,, 8§-9
,, 10-12 ,, ,, 8§-8;}
,, ‘lg-6
Mogadore ,, 35-55
SKINS. s. d. s. d.
Nutria.......... per (102. 10 0-15 0
,, 7 0-52 0
Deer, Buenos Ayres large red..... per skin 1 0- 2 0
small thin ,, 0 6- 0 9
Vienna, Buenos Ayres 8zW. Coast ,, 2 6- 3 0
Sheep—Mogadore per doz. 15 0-22 0
Buenos Ayres ,, 10 0-18 0
Trieste ,, 10 0-15 0
Tuscan ,, 16 0—18 0
,, 12 0-28 0
Italian
128
LEATHER.
SncrroN II.-—-VEGETAJBLE SuBsrxNcEs usnn IN
TANNING.
The tannin or tannic acid of different vegetables
does not appear to be the same astringent substance.
The differences between tannins from different sources
are small, and are chiefly interesting to the chemist.
There are, however, certain broad features which are
alike in all. Tannin is characterised by an astringent
taste, and by its bluish-black or dark-green precipi-
tates from aqueous solutions, by the solution of salts
of the peroxide of iron: it also affords a dirty-white
or brown precipitate with a solution of gelatine. A
solution of protosulphate of iron does not ‘precipitate
a solution of tannin, until, by exposure to the air,
oxygen is absorbed, and a peroxide of iron is formed.
This change, however, is very rapid. If cold aqueous
solutions of tannin and animal gelatine (such as glue,
size, or isinglass) be mixed in certain proportions,
both are thrown down as a precipitate, which is called
maize-gelatin: it contains about half its weight of
tannin. If heat be applied, or the acid be in excess,
the precipitate forms, on stirring, a viscid, elastic
mass, resembling caoutchouc.
Tannin is most easily procured in its pure state

2.6 8.!1. £‘ .9. (1.
Italian per 120 6 0 0—- 8 10 0
Lamb......................... ,, 4 10 0- 6 5 0
Ancona Kid ,, 7 O 0— 8 10 0
Lamb ...................... .. ,, 5 0 O— 6 l5 0
Tuscan Kid ,, 8 0 0-10 10 0
Lamb ,, 5 10 o- 9 10 o
Naples ,, 4 10 O—- 6 10 0
Lamb ,, 4 10 o-_ 5 10 0
Sicily ,, 5 0 0- 7 0 0
_ ,3, ,, 3 o 0— 4 10 o
, ' Trieste-Kid ,, 5 o o- e 5 o
' ‘ _ Lamb ,, 4 10 o— o 10 o
Bilboa Kid ,, 7 o o- s 10 0
Lamb ,, 4 10 0- 7 o 0
Spanish Lamb ,, 5 15 0- 8 0 0
{East India per (102. 0 5 0— O 7 0
B'uenos Ayres Lamb................ ,, 0 6 0— 0 12 0
Great, Lisbon ,, 0 6 0- 0 18 0
,, 0 l5 0-—- 2 9 0
Mogadore ,, 0 12 0— 0 18 0
Seal-Fur—Large wigs skin 0 5 0- 1 12 0
Middlings and smalls ,, 0 12 0— 1 15 0
Large pups ............ .. ,, O 11 0—1 8 0
Newfoundland ....... .. ,, 0 2 6— 0 6 0
Greenland ............ .. ,, 0 1 l— 0 5 6
' Honsnnxrn.
Long Combed, Buenos Ayres, s. d s. d
per lb. 1 9 — 2 3
Tails rough, Buenos Ayres ....... .. ,, 0 10 - 2 0
Good ,, 0 9,1,— 0 10,1
Fair mixed ,, 0 7%— O 8;}
Common and short..................... ,, 0 6 — 0 7%,-
Ox and Cow, on the skin ,, 0 7 — 0 7%
Ditto clean and free of ,, 0 8 -— 0 8%
Russian long combed ,, 2 0 — 2 2
2d quality ................... .. ,, 0 9 —- 0 10
,Short ,, 0 6 —- 0 7
Hearts.
Cape 123 48 0 —86 0
B. Ayres, M. Video, 8: Rio .1. 0x ,, 26 O —45 0
Small Ox and Cow ,, 12 0 —24 0
Buffalo cwt.16 0 —38 0
Deer ,, 24 0 -—35 O
Tips—Buenos Ayres ,, 18 0 -22 -0
North American............... ,, 18 0 —20 0
Buffalo ,, _17 o _22 0
Bones. .8 s. d. .8 s. (1.
River Plate per ten 4 10 0-6 10 0

from gall-nuts. These must be coarsely powdered,
and placed in a glass percolator, ‘Fig. 1287, the
bottom of which is plugged with cotton. Ether
containing a small quantity'of water is
then poured in, and after several hours,
when the liquor has filtered through,
more ether is added. The liquor col-
lected in the lower vessel separates into
two layers, the lower of which is of
an amber colour, and consists of a solu-
tion of tannin in water. The upper
solution contains gallic acid and some
other matters. The aqueous solution,
on being gently evaporated, leaves a
shining, porous, uncrystallizable mass
of tannin, nearly pure. In this way
from 35 to 4.0 per cent. of tannin may ‘I
be obtained from galls. It may be pre- '
served in close vessels without change.
Tannin is soluble in water, and the solu-
tion has the properties of a free acid.
Exposed to air, it absorbs oxygen, disengages an equal
volume of carbonic acid; the tannin disappears, and
two new products, viz. yallz'e acid and ellzlgz'c acid, are
formed. The former is soluble, the latter an insoluble
powder, of a yellow-grey colour. Tannin is precipi-
tated from its solutions by sulphuric, muriatic, phos-
phoric, boracic, and arsenic acids. If the compound
with sulphuric acid be boiled for a few minutes in
dilute sulphuric acid, gallic acid is formed, which is
deposited in crystals on cooling.
Gallic acid exists ready formed in gall-nuts, sumach,
mango-seeds, divi, valonia, tea, &c. and is probablyr
formed in all cases from the decomposition of tannin.
It is not so soluble in cold water as tannin, but is
very soluble in hot. It does not combine with gelaL
tine or gelatinous tissues as tannin does, and hence
is little or no use to the tanner. The tannin of
gall-nuts and sumach is more liable to pass into
gallic acid than any other description of tannin.
This change in the case of gall-nuts, and probably,
also, in other cases, is expedited by the contact of the
insoluble vegetable matters which remain after the
tannin is extracted. Pyroligneous acid retards the
decomposition of tannin, while tartaric, malic, and
vegetable acids in general, accelerate it. Sumach is
peculiarly liable to fermentation, probably in conse-
quence of the malic acid present in the leaves. Hence
it is of great importance to the tanner to become
acquainted with the circumstances which favour the
conversion of tannin into gallic acid, and to avoid
them if possible, for this is a positive source of loss.
In the spent or waste tan liquors there is a consider—
able proportion of gallic acid. There is an opinion
among tanners, that the presence of gallic acid is
useful; and when hides have been cleansed with
lime-water, they are left for a time in the waste
liquor, the gallic acid of which is said to expand the
hides, and facilitate the penetration of the solution of
tan, when the hide is transferred to a stronger liquor.
Now, as almost any other acid would answer this
purpose (indeed water soured with sulphuric acid is so

lg. 1287.
LEATHER.
' ‘1259
used), it certainly does appear to be a circuitous as
well as costly method of getting an acid by the
decomposition of tannin.
Oak-cart is the most important tanning material
in common use. [See BARK] It must be stripped
in spring, for it then contains more tannin than bark
out in autumn, and this again more than that which
is taken in winter. The trees are felled about May:
but in some cases, a small quantity is cut down about
two months later: this is called midsummer bar/t,
but it is now seldom seen in the market. The quan-
tity of tannin is considered by tanners to be in pro
portion to the freedom with which the sap flows at
the time of stripping, and to the facility with which
the bark is removed. Bark which has the appearance
of having been removed with difiiculty, fetches a
lower price than that which appears to have come
oil’ with ease. The richest bark is obtained in the
warmest spring, for then the sap is most abundant.
A few days of cold previous to the felling and strip-
ping reduces the proportion of tannin and sap. The
bark of coppice trees about 12 years old contains
more tan than younger trees, and these more than
old ones. According to Stenhouse, the tannin of
oak-bark when subject to destructive distillation does
not afford pyrogallic acid, as the tannin of gall nuts
does : hence the tannin of bark is probably not iden-
tical with that of galls. Oak-bark contains from 5'6
to 60 per cent. of tannin, and in this as in other
astringent barks the tannin is contained solely in the
inner white layers next the alburnum, the middle
coloured portion containing most of the extractive
matters, and the epidermis or exterior but little ex-
tractive and no tannin. From A to 6 lbs. of oak-bark
are required for the production of 11b. of leather.
Leather tanned with oak-bark is considered superior
to that made with any other tanning material, but
the process is slower. The price of good English
oak-bark per load of 4:5 cwt. delivered in London in
June 1852, varied from 1%. to 131. 10.9.1
Sumac/t is used in the manufacture of the lighter
and finer kinds of leather. It consists of the powder
of the leaves and young branches of shrubs growing
in the south of Europe and known to botanists as
Rims cotz'aas, Veaas sumac/t, or the wild olive; Rims
coriarz'a, hide or elm—leaved sumach. The former is
used most extensively by the dyer and calico printer;
the latter by the tanner. Of late years sumach leaves
have been imported entire in consequence of the
adulteration which formerly prevailed. Its per-centage
of tannin has been found to vary from 164: and 16:2
in Malaga and Sicilian specimens, to 10, and 5 inVir-
ginia and Carolina sumach. The tannin appears to be
identical with that of galls, and a good deal of gallic
acid exists ready formed in sumach. When mixed
with water it is more apt to ferment than any other
tanning material. The price of Sicilian sumach in
June 1852 was from M8. 603. to 16.9. per cwt.

(1) When the bark has’ been stripped, the long pieces are set
up on end (stacked) to dry. In the present year, 1852, after the
stacking, a succession of three‘weeks’ rain greatly deteriorated the
bark, by washing out a portion of the tannin.
VOL. II.

Dim‘ or divi-tlz'vi is the pod of a leguminous shrub,
C'arsalpz'a coriarz'a, a native of South America, and
growing to the height of 20 or 30 feet. It is
imported into Great Britain from the West Indies,
and from various parts of the north coast of South
America. The pods are of a dark brown colour, about
3 inches long, but curled up as if by heat in drying.
The whole of the tannin exists in the rind below the
epidermis: the taste is highly astringent and bitter,
but the inner skin, which encloses a few fiat seeds, is
nearly tasteless. Divi contains a considerable quan-
tity of tannin, and also a mucilaginous substance
which prevents its being used in dyeing and calico
printing. It soon ferments when mixed with water.
The leather made by means of divi is very porous, and
is of a brown or deep brownish red colour. The
colouring matter is produced somewhat suddenly, and
appears to be the result of fermentation. If air be
excluded the colour is not produced and the leather
is equally good. The price is from 81. to 9i. per ton.
Val'oaz'a consists of the acorn-cups of Qacrcas
Egz'lops, or prickly-cupped oak, growing in the Morea.
As soon as the acorns are gathered they are partially
dried, and conveyed by mules to Smyrna for shipment.
They are here stored inwarehouses for some months,
in layers of from 3 to 5 feet in thickness. The cups
undergo a slight fermentation, and in drying, the long
spreading scales which confined the acorn contract,
and allow the acorn to fall from the cup. The acorns
which contain no tannin are separated from the cups,
and those of the latter which are damaged are also
picked out. The diameter of the cups‘ including the
scales is a little under 2 inches. A smaller kind of
valonia, camata, bears a higher price than the common:
it is somewhat richer in tannin, and is chiefly used by
the silk dyers. Good valonia is thick, full grown,
and bright in colour. If exposed to rain after being
gathered the cups lose a portion of their tannin and
become of a deeper colour. About 2 lbs. of valonia
are required for the production of 1 lb. of leather,
which is said to be less permeable to water than that
made with oak-bark, and so heavy as to make valonia
the cheapest of all tanning materials, except catechu
or terra. A mixture of valonia and oak-bark may
be used with good effect.
C’az'ec/za, cats/z, terray'apoaz'ca and term, are inspis-
sated aqueous extracts from the bark, wood, and
probably the leaves of the acacia catechu and Uacarz'a
gambz'r. In commerce, the two sorts are known as
Cza‘ecfia, or Gambz'er, and Cate/z. Most of the catechu
from Bombay is said to be from the former tree,
and that from Bengal from the latter. Bombay
catechu or cutch is the richer in tannin; it is of a
dark brownish red colour, internally as well as exter-
nally, and of specific gravity 1'88. Bengal catechu
or terra is of a light brown colour internally: its
specific gravity is 1'28. Both are astringent and
bitter, leaving a sweetish taste on the palate.
Catechu is said to be prepared by felling the
tree, cutting it up into small pieces, and boiling
with water in a narrow mouthed vessel until only one-
half of the original bulk of liquid remains. The solu-
K
130
LEATHER.
tion is then transferred to a wide earthen vessel,
in which the evaporation is continued: the inspissa-
tion is completed by exposure to the sun with
occasional stirring. Before the extract is quite dry
it is placed in cloths, strewed over with the ashes of
cow-dung, cut into small lumps and again exposed to
the sun. Mr. Parnell remarks that the appearance
of the dark-coloured variety, or cutch, answers better
to the description of this‘ mode of preparation than
that of the light-coloured variety. This, which is
more pulverulent than the former, is ‘said to be pre-
pared by mixing the concentrated decoction of the
tree with a pulverulent substance resembling starch.
This powder is disposed in a thin layer on a floor or
shelf, and the concentrated infusion or decoction
allowed to run over the floor, and be imbibed by the
powder. When the mass is become stiff by drying,
it is cut up into small lumps and dried in the sun.
Both kinds of catechu contain about half their weight
of tannin, which differs from that of galls in affording
olive green precipitates with salts of iron, and
yielding no pyrogallic acid on destructive distillation.
The tannin of catechu is soluble in cold water.
Catechu also affords a peculiar principle, which has
been named calec/ziiz and calecimie acid, which is not
soluble in cold water, but slightly so in the solution
of the tannin of catechu. Catechu is extensively used
in India in tanning, and of late years has also been
much used in this country. It tans the skins with
great rapidity, but the leather is light, spongy, per-
meable to water, and of a dark reddish fawn colour.
The light-coloured variety of catechu produces a
softer leather than that tanned with cutch. Catechu
produces but little of the deposit of bloom which is
yielded by oak-bark, valonia, and divi. A pound of
catechu is said to be sufficient for the production of
about a pound of leather.
Catechu is used by calico printers, to produce a
fast bronze on cotton fabrics.
Myrobalama—The substance known by this name
is the fruit of several East Indian trees, and is used
in India as a substitute for galls. When ripe, the
fruit is pear-shaped, deeply wrinkled, and of a brown-
ish yellow colour: it weighs from 70 to 100 grains.
The husk contains the whole of the astringent matter,
some mucilage, and a brownish yellow colouring sub-
stance, which is used in India for dyeing yellow.
The husk is easily separated by bruising the nut,
‘ which it encloses. The tannin of myrobalams differs
slightly from that of galls.
in rather large proportion.
Gallic acid is also present
The price of myrobalams
' in June 1852 was quoted at from 6l. to 10l. per
ton. , .
Elimosa, or Wattle-bark, is procured from different
species of mimosa, which grow in Australia and New
Zealand. Itis sometimes imported in the form of fluid
extract, as wellas bark. The leather produced by its
means is of good quality, but of bad colour. The
bark must ‘be finely ground, or it does not give up
the whole of itstannin to warm water.
‘ Cork-tree lar/a-E-The outer dead bark of the cork
oak, known as cor/e, may be removed without injury

to the tree, [see Conrg] but the inner bark which is
‘used in tamiing cannot be removed without destroy-
ing the tree. In Corsica, Spain, and a few other
countries, where the tree is abundant, the bark is
removed for tanning. This bark contains twice as
much tannin as oak-bark of average quality. The
tannin appears to resemble that of catechu: it affords
scarcely any bloom, and gives a dark colour to the
leather. " - - ' .
Lara/t lac/t is sometimes used as a substitute for
oak bark,'for tanning the inferior sheep skins, known
as basils. _ It contains a‘ good deal of tannin, mucilage,
and some resin. -
Willow lard—The bark of the common willow
contains, according to Davy, 2'3 per cent. of tan-
nin, and that of the Leicester willow 6'8 per cent.
Danish leather, which has a peculiar and agreeable
odour, and is used for making gloves, is prepared
from kid and lamb skin, by means of willow bark.
The same bark is also used in the preparation of
Russia leather, but the odour of that leather is pro-
duced by the oil of birch-tree bark.1
The following table is from a more elaborate one,
constructed by Sir H. Davy, to show the value to
the tanner of the different substances named. The
numbers express the relative quantities of dry hides
capable of being tanned by equal weights of the
materials :—-



Bombay Catechu............................... 261
Bengal . 231
Nut 127
White inner bark of Leicester willow 79
Sicilian sumach 78
White inner bark of young oak 77
-———-——- old oak 72
Spanish chestnut..................... 63
Souchong Tea 48
Green 41
Entire bark of Leicester willow 33
oak 29
—-——---——- Spanish chestnut 21
Middle bark of oak 19
Leicester 16
-— Spanish chestnut 14
Entire bark of elm 13
——————— Common willow 11
Mr. Parnell very properly remarks, that “if the
tannin and all the other ingredients of these astrin—
gent matters were of precisely the same nature, such
a table as the above might exactly indicate the
respective values of the different substances. But

(1) The following extract from Messrs. Goad 8c Rigg’s Prices
Current for 1851, will show the sources and prices of the imported
barks. They are all free of duty.
Oak Bark— s. £ 8.
Flemish ton. 5 0 —— 7 0
,, ,, 4 5 — 5 10
German ,, ,, 4 10 — 5 10
Cork Tree Bark——
Spanish ,, ,, 7 0 —- 8 0
Leghorn..................... ,, ,, 6 0 —- 7 0
Mimosa Bark................ ,, ,, 8 10 -— 9 10
Gambier [Terra Japonica] ,, ,, 16 10
Diet Divi—
Savanilla.................... ,, ,, 8 0 — 9 0
Maracaibo ................ .. ,, ,, none
Valom'a— I
,, ,, 14 0 — 15 0
Morea........................ ,, ,, 10 0 -— 12 0
Camata....................... ,, ,, 14 0 — 16 0
LEATHER.
131
the tanner has to take cognisance of other circum-
stances than the actual proportion of astringent
matter contained in his material; for it is well known
that a considerable difference may be detected in the
quality of leather made from similar skins, and in the
same manner, but with different vegetable matters,
though the leather be perfectly tanned; this can only
be ascribed to a difference in the nature of the tannin,
or the accompanying mucilaginous and other matters.
The leather produced by means of larch-bark, for
example, is far inferior to that made with oak-bark,
though similar skins be operated on, and the tanning
be continued the same length of time; and catechu
and divi produce a more porous leather than oak-bark
or valonia. The quantity of colouring‘ matter present
in the tanning material, and the susceptibility of the
latter to produce a soluble colouring matter on ex-
posure to the air, form another important subject for
the consideration of the tanner. The quality of the
leather may not be in the least affected by the attach-
ment of vegetable colouring matters; but the pre-
judice of purchasers requires that both upper and
sole leather should possess a uniform dull fawn colour,
or what is still more preferred, a yellowish fawn colour.
The infusions of several of the tanning materials,
which have been recently introduced, either contain,
when first made, or afford on exposure to the air,
dark reddish brown colouring matters, which become
permanently attached to the leather. The slow con-
version of tannin into gallic acid, by exposure‘ to the
air, is generally, and. probably always, attended with
the formation of a dark brown substance, (the apo-
th‘eme of Berzelius,) sufficiently soluble in water to
colour the leather throughout its entire thickness.
The principal objection to the use of the cork-tree
bark, consists in the presence of such a colouring
matter as this in the infusion of the bark, particularly
after it has been freely exposed to the air; and light
catechu and cutch, though generally about twice the
price of oak-bark, would be esteemed cheaper than
any other tanning material, were it not for the reddish
brown colour which they communicate to the leather.
Although the recent infusions of all vegetable tanning
materials contain more or less of this apotheme, yet
there can be no doubt that the quantity is greatly
increased by a free exposure to the air: hence another
reason for protecting the pits as much as possible
from all oxidating influences.”
In order that the tanner may estimate the values
of different kinds of bark, or of different varieties of
the same bark, he must be able to determine the pro-
portion of tannin in each specimen 3 but this is not
easily done. The usual test for tannin, as already
stated, is some form of gelatine, such as glue or
isinglass, a solution of which is mixed with a known
weight of tanning material, also in the state of solu-
tion; the precipitate of tanno-gelatine is then weighed,
and the proportion of tannin thus ascertained.‘ Such
a result, however, is not trustworthy, because the
composition of tanno-gelatine varies with the strength
of the solution either of gelatine or of tannin, and
some varieties of tannin produce larger precipitates

with gelatine than other kinds. Thus, an infusion of
cork-tree bark, or of cutch, affords a smaller pre-
cipitate than an infusion of gall nuts of similar
strength. A better test than the above is said to be
sulphate of quinine, the solution to be acidulated with
a few drops of sulphuric acid; this, it is said, will
precipitate tannin from its solution perfectly, and the
composition of the precipitate is constant. The
tanner is accustomed to use a kind of hydrometer,
called a tar/cometary for ascertaining the strength of
his infusions of bark, or ooze, as they are called.
The instrument is graduated by the standard of pure
water, and an ooze is said to be strong or weak
according as the stem of the instrument rises above
or sinks below the water mark. Now as the ooze,
in addition to the tannin, contains colouring matters
in solution, and these vary in different barks, and in
some of the new tanning materials are abundant, it
is obvious that no method of taking the specific
gravities of infusions of bark, will afford correct in-
dications of the amount of tannin contained in them.
The tanner judges of the strength of ooze by its
taste, which in strong oozes is highly astringent.
Perhaps the best method of judging of the valueof
a tanning material, is to take a piece of perfectly dry
prepared hide, or skin, and digest it in a known
quantity of infusion of the tanning material which is
to be tested, until all the tannin &c. shall have
separated. The skin is then taken out, slightly
washed, dried and weighed. The increase of weight
is the weight of tannin and other matters required.
An experiment of this kind may be performed in the
course of a few hours, if the skin be pared thin,
and a gentle heat be employed: there should be a
slight excess of tannin in the infusion, in order that
the skin may be saturated with tannin.
SncrIoN TIL—PREPARATION on THE SxINs ron
TANNING.
When hides are received fresh from the slaughter
house, they are washed, if water be abundant; and
the horns are removed for the comb maker. Dried
or salted skins are soaked in water for 10 or 141
days, with occasional friction, and in some cases a
kind of fulling-mill is used to produce that soft supple
state which is necessary for the working. After the
washing, green hides are worked with a knife-on the
flesh side, to get rid of flesh and fatty matters.
Salted hides are occasionally scraped at this stage,
but dried hides do. not require this treatment.
The next operation is to get rid of the hair and
scarf skin, for which purpose the hides are put into
oblong troughs, or pits, sunk in the earth, and con-
taining a mixture of lime and water of 3 or 41 different
strengths, in the different pits. They are left for a
day or two in the weakest, and then transferred to
the others in succession, until, in the course of two
or three weeks, depending on the texture of the hide
and the state of the atmosphere, the lime has dis-
solved the hair sheath, and combined with the fat of
the hide, to form an insoluble soap. The hides are‘
kcmrZZerZ every day, to equalize the action of the lime.
x 2
132
LEATHER.
4 that‘
Handling is a term in common use in the tan yard;
it consists in taking the hides up out of the pit, and
allowing them to drain in a heap for an hour or two,
when they are returned to the pit. The lime water
is stirred up before the introduction of the hides, so
that solid particles of lime may cover the surface.
When the hair and epidermis yield to the touch,
the skins are taken out, and scraped upon a cylin-
drical table, called the beam, with a curved two-
liandled iron scraper, called the anbaz'rz'ng bnge ,' it is
concave, and fits the curvature of the beam; the
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Fly. 1288. UNHAIRING HIDES.
hair comes off easily, leaving what is called the grain
of the skin. The hide is then flee/zed, that is, the
beam man passes a knife, called the flashing lang'fle,
over the inner surface, for completing the removal of
flesh and fat. This knife is convex, and its edge
being sharp, 'the operation is that of cutting, not
scraping, as in the process of unhairing. It requires
great skill to shave or plane off the flesh and fat
down to the surface of the true skin, and yet not to
cut it. After being thoroughly washed in water,
and again scraped to get rid of the lime, the ears
and other projecting portions are cut off for the
glue maker; the hides are then fit for the tan-pit.
They are, however, sorted, to separate those which
are sound from those which contain warble, or wzmnal
boles, formed by the larvae of a species of gad-fly,
(@sbnns bonz's,) which deposits its eggs in the hide of
the ox. Hides containing these bot-bales make very
good sole-leather, but cannot, of course, be used for
hose or bucket leather, or for foundry bellows, and
similar purposes.
The use of lime has many disadvantages; it dis-
solves a portion of the membrane which would make
good leather, renders the surface unequal, and the
action of the tan uncertain. Hence many attempts
have been made to get rid of this material. By one
method they are hung up in a snzo/ee bonse, or close
room, heat-ed a little above the ordinary temperature
by means of a smouldering fire, fed with spent tan,
which produces no flame. Here the hides enter into
incipient fermentation, which softens the epidermis

and roots of the hair. In Germany, with the same
view, the hides are piled up in a heap, and covered
with spent tan: in a short time they begin to putrefy,
and without great care are liable to be spoiled. By
another plan, they are piled up on a bed of litter, and
covered with litter for twenty-four hours: then turned
over, and afterwards frequently examined to see
when they are fit for unhairing, These plans are said
to be more objectionable than limeing. In France
small quantities of salt are added, to prevent the
putrefaction of the gelatinous tissues, but not sufli-
cient to retard that of the hair-sheath and epidermis.
In some parts of the United States of America, the
hides are exposed to confined air, kept damp by the
spray of water, and it is said that in from 6 to 12
days the hair comes ofl easily. It is stated that no
putrefaction takes place, the effect being attributed
solely to the softening action of moisture. The grease
must be got rid of in some other way, for it is one
of the uses of the lime to combine with it to form
a soap, as already noticed.
Dilute acids serve the same purpose as lime, and
are used in some tanneries ; sulphuric acid, very
dilute; sour milk; pyroligneous acid; fermented barley,
rye water, and bran, are all in use; the two latter are
sometimes applied to the skins after the limeing.
Dilute acids have the effect of swelling the pores of
the skins, so as to enable the tan liquor to penetrate
them more easily. When this operation is performed,
it is called raising, and a common solution for the
purpose is made by the addition of 1 part oil of
vitriol, and 1,000 parts water; a moderate heat being
applied, the raising is completed in an hours. Oxalic
and tartaric acids are better raisers than sulphuric,
but much more expensive.
In kips and skins all the lime must be removed,
or a hard leather will be the result. After limeing,
they are exposed to an alkaline solution, called babe,
or grainer, consisting of the dung of hens, pigeons,
and other domestic birds, in which they remain 8 days,
according to the temperature. During this time they
are frequently stirred, and also taken out and scraped
on the beam. 10 or 12 gallons of dung are sufiicient
for bazfz'ng 100 skins. By this process they are made
soft and pliant, and the lime is almost completely sepa-
rated. For morocco, dog’s dung (formerly called album
Greeenm) is also used for the purpose. It was sup-
posed that the lithic acid of the dung combined with
the lime, and that the ammonia produced by the putre-
faction of the mixture formed a soap with any remain-
ing fat of the hide. It is more probable, however,
that muriate of ammonia is the most active constituent
of the dung; which, by dissolving a portion of un-
combined lime, forms chloride of calcium, and free
ammonia. The animal matters of the dung dissolve
a portion of- the gelatinous tissue, and in warm
weather the grain is discoloured from this cause.
The process of hating is disgusting, and its present
imperfect condition ‘is not creditable to our chemists.
Something, however, has been done. In 1840 Mr.
Robert Warington proposed carbonate of ammonia
as a bate; this does not dissolve the lime out of the
LEATHER.
133
skin, but destroys its causticity, by converting it into
carbonate of lime. Bran water is the bate for sheep
skins.
SncTIoN IV.—Tnn Pnocnss or TANNING.
The tan-yard usually occupies a considerable extent
of ground, and above it are lofts for drying the tanned
leather. The tan-pits, which are formed in the earth,
are oblong in shape, from 6 to 8 feet in depth. In
forming a tan-pit the whole ground is first excavated,
and covered with clay; the boards which form the
lining to each pit are first built up into chests, then
adjusted in their places, and filled with earth to weight
them down; the various pipes for conveying the ooze
are next arranged and fixed, and lastly, the spaces be-
tween the wooden chests are filled up with clay, and
made level with the surface of the ground, producing
the appearance of a number of pits, in rows side by
side, with narrow spaces between them for the con-
venience of the workmen. In Fig. 1289 these spaces
are made wider than is usual in the modern practice.












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TAN—YARD.
it
it.- .
The oak-bark is ground in a mill attached to the yard,
and the ooze is generally prepared before it is brought
into contact with the skins. By the old method it was
made in the pits where the hides were impregnated, the
ground bark and hides being laid in alternate layers in
the tan-pit, which was then filled up with water. When
the ooze appeared to be spent, the pit was emptied
and refilled with fresh bark and water, and so on many
times. By this process, which was spread over as much
as 15 months, a very superior leather was produced.
According to another of the old plans, a layer of
spent bark 6 inches thick was spread over the bottom
of the pit; upon which was placed a layer of fresh
bark finely ground, 1 inch thick ; upon this was
spread a hide quite flat; then another layer of fresh
bark, then another hide; then another layer of fresh
bark, and so on until the pit was filled; the whole was
then covered with a stratum of bark 6 inches thick,
called the lzat .- the whole was then well trodden
down, and in some cases planks laden with heavy
stones were imposed. The pit was left in this state

for 2 or 3 months, when it was emptied, the hides
stretched and re-arranged in the pit with fresh layers
of bark. The process was again repeated 3 or 4:
months later, and lastly the pit was filled up with
strong ooze, which completed the process. This
slow method was sometimes varied by pouring a little
water into the bottom of the pit, the vapour of which
assisted the absorption of the tannin. But the more
usual plan was to fill the pit with soft water after the
above arrangement was made, and at the last filling
to use ooze instead of water.
In the modern practice of tanning ooze instead of
water is used at every stage: the hides are more
rapidly impregnated, and stronger oozes are employed
than formerly. The ooze is prepared by passing cold
water through a stratum of the powdered bark or
other astringent matter, until, by successive infiltra-
tions, it is deprived of all its ingredients which
are soluble in cold water. Some tanners make
their ooze with hot or lukewarm water, for which
purpose steam is introduced by a large iron pipe to
the bottom of a deep pit containing a mixture of the
vegetable matter in water. A little above the true
bottom is a false bottom, through which the infusion
filters into the space below, from which it is with-
drawn by a pump. According to another method,
water is first applied to nearly exhausted bark, which
is digested in it for a long time at a moderate heat:
the weak ooze thus formed is pumped into a pit con-
taining more bark not so much spent as that in the
first pit. From this second pit it is transferred to
another containing richer bark, and so on through
several pits until it arrives at a pit containing fresh
ground bark, and from this the ooze is withdrawn
for use.
It is a common practice to introduce the skins into
a nearly spent ooze, and to remove them into oozes
of gradually increasing strength. Oozes are of two
kinds according to their strength, viz. handler liquor
and layer Zigaor. The tanning is completed in the
handlers, and the stronger oozes or layers are used to
produce the deposit of 6100212.
The skins are usually arranged in horizontal layers
for economy of space, but a few tanners prefer to
suspend them vertically. Some use oozes only;
others introduce a little ground bark. If oozes only
are used, the skins are at first handled once or twice
a-day in the first ooze, every second day in stronger
handlers, and afterwards about once a-month in the
layers. In the process of handling, the hides are
taken out by two men one at a time, by means of
blunt pointed hooks furnished with long handles,
(see Fig. 1289,) and are placed regularly one on
another, on a sloping wooden rack placed over the
adjacent pit; they are left to drain for one or two
hours, and are then returned to the pit, the last hide
taken out being the first to be returned.
Chemistry has not done much for the tanner except
to discover a variety of new tanning materials, none
of which, however, appear to be equal to the ancient
material, oak-bark. The tanners themselves have
endeavoured to abridge the long, costly, and tedious
13A
LEATHER.
process of tamiing thick leather. These attempts
have not been very successful, but we may notice a
few of them. In the process by Mr. Cagswell, an
American tanner, the hides or skins are placed upon
layers of saw—dust or other soft porous material con-
tained in shallow rectangular boxes; these are arranged
one about a foot over the one below; the“ edges
of the hides are raised a little, so as to'convert each
into a shallow trough, into which the ooze is admitted.
As the .ooze becomes exhausted ‘and filters through
the hide and the saw-dust, it passes .off by a channel
in the'bottom, of thebox, and the hide is refilled with
fresh ooze. This plan, which gets rid .of the labour
of handling, is said to be expeditious, but it is neces-
sary, to complete the tanni'ngof the edges, to put the
skins into pits for three or four weeks, which, of
course, is an objection. -
The labour of handling is also got rid of by arranging
the skins vertically, for which purpose they are at-
tached at the edges to a horizontal wooden frame
suspended by pulleys and ropes, and are thus lowered
into or raised out of the tan-pitall at once.
A quick method of tanning was patented by Spils-
bury in 1823. The hides having been unhaired and
cleaned, are carefully examined to see that they are
sound, and if any holes exist they are carefully sewn
up. A hide is then stretched across a rectangular
frame, and upon this hide is placed another frame
secured by screwsand bolts: upon this is placed a‘
second hide and then another frame similarly secured,
this system of framing forming a flat water-tight
vessel bounded by the two hides; the whole is then
placed in a vertical position, and ooze admitted into
the cavity between the two hides by a pipe leading
from an elevated cistern, the air being let out by a
stop-cock in the frame. The hydrostatic pressure
forces the ooze through the pores of the hides by a
process of slow infiltration. When the tanning is
completed, the supply of ooze is cut off, the liquor
drawn off, the bolts are unscrewed,-and the frames
removed: the compressed edges of the hides are
clipped off, and the hides finished in the ordinary
manner. ~ . ~ .
In Drake’s patent process the hides are sewed
together so as to form a water-tight bag, which is
filled with ooze, and to prevent the sides from bulging
out, the bag is placed between two vertical racks.
The ooze slowly escapes to the outside, and is re-
turned to the bag. As the tanning advances the‘
a temperature of the room is raised to facilitate the
evaporation from the surface, and thus to promote
the percolation. Thepressure of the racks made the
texture of the leather unequal, a defect which was
remedied by Chaplin, but the plan was not successful.
An attempt was made to imitate the old Danish
process, viz. to keep the bags full of ooze immersed
in pits full of ooze; but the great space thus required
was an objection, and is now, we believe, only prac-
tised in tanning small skins with sumach.
Air-tight vessels have been tried, from which the
air has been pumped out after the skins were arranged
in them ; ooze was then admitted, and forced into the

pores by hydrostatic pressure; the operation being
repeated from time to time with stronger oozes. The
abundant evolution of air, or of some other gases
from the tanning liquor, defeated this plan.
Mr. Herapath of Bristol took out a patent for a
new process of tanning, some years ago. According
to that gentleman, the great obstruction to rapid
tanning is, that the skins retain so much of the spent
ooze,‘ that when placed in a stronger one, the latter
cannot enter the pores already saturated with water,
except after weeks or months of maceration, during
which time the exchange is being slowly made. By
the new plan, in passing the skins from a weak to a
stronger ooze, they are compressed between rollers,
a pair of which is erected over each pit. The lower
roller is about 30 inches in diameter, and is covered
with horse-hair cloth: the upper roller, which is
loaded, is about 18 inches in diameter, and is covered
with woollen cloth. 50 hides are introduced into
each pit ; these are sewed together with twine, so as
to form an endless band, which is introduced between
the rollers, and as these rotate, the hides are succes-
sively lifted from the bottom of the pit, and then
returned into it for a fresh supply of ooze. Mr.
Herapath states that each ooze becomes exhausted
about 2° of the barkometer in 24 hours, when it is
pumped into the next pit of the series, and fresh
ooze introduced. It is said, that by this process a
strong hide may be completely tanned in 6 or 8
weeks, and calf skins and hips in from 20 to 30 days.
Butts can be finished in 4 months, and the increase
in the weight of leather, as compared with that made
in the usual way, is stated to be as 34ilbs. to 24 lbs.
The leather thus ‘prepared is said to be hard and
brittle, an objection which applies to all the quick
processes.
Mr. Squire, of Warrington, has invented a process
which is, perhaps, the least exceptionable of all the
quick methods. The hides and skins are introduced
into a horizontal wooden cylinder, 10 feet long, and
5 feet in diameter, four-fifths filled with hides and
ooze. This cylinder is made to rotate on an axis, at
- the rate of 6 or 8 revolutions per minute. The in-
terior of the drum is furnished with projecting ridges,
which increase the agitation and prevent the hides
from rolling into balls. A hot ooze, and fresh tan-
ning material is used in this process. This soon
becomes ‘spent when the drum is opened, and fresh
materials are introduced. It is of importance not to
neglect this at the proper time, since spent tan liquor
is very injurious to leather. The advantages of this
process are—1, the agitation of the skins; 2, the
use of a warm ooze; 3, the exclusion of atmospheric
air; and .41, the rapidity of the process, 14. days
sufiicing for the tanning of thick kips. The exclusion
of the air prevents the deposit of colouring matters
on the leather—even divi can be used without such
a result; whereas, inopen pits a reddish colour would
be imparted, such as would make the leather unsale-
able. In this process the leather is rather deficient
in bloom. What is this bloom, and what is its use?
These questions have not been satisfactorily answered
‘LEATHER.
135
either by the chemist or the tanner. It is a test by
which the purchaser judges of the value of the leather,
for a good deposit of bloom cannot be obtained unless
a considerable time be allowed for the tamiing. Most
of the new tanning materials produce a difi’erent
bloom from that of oak bark; while others yield
hardly any bloom at all. All leather prepared by the
slow process, contains a, considerable quantity of
tannin more than is necessary for the complete satu—
ration of the gelatinous tissue. This surplus tannin
is not chemically combined, but only mechanically
attached to the exterior of the fibres. By digesting
chippings of leather in water, some of this mechan-
ically attached tannin may be dissolved out. In
the processes of finishing sole leather, about to be
described, it is possible, as Mr. Parnell suggests,
that ellagic acid is formed, and it is this substance
which forms the bloom. When catechu is employed
as the tanning material, the bloom is then said to
consist of catechuic acid, which forms the greater
portion of that part of the catechu which is insoluble
in cold water.
In the course of the 9 to 15 months required for
tanning hides, the whole of the skin or dermis dis-
appears by successive formations of the compound of
gelatine and tannin, on both sides of the hide, until
all traces of the animal substance disappear. In an
early stage, a thick whitish line is seen on cutting
across a hide; this is a portion of the skin itself:
but as the process proceeds, this also disappears, and
the tanner knows that the process is complete.
When the hides are taken out of the last bloomer
pit, they are slightly washed in water, drained, and
suspended from poles in airy lofts to dry ; once or

S I‘RIKING' HIDES.
Fig. 1290.
long cylindrical horse, and struck or smoothed with
a triangular steel knife, the surface being occasionally
sprinkled with a bunch of butcher’s broom dipped
in water. This brings the bloom up to the surface.
Of late years the bloom has been struck oif ‘so as to
produce a ruddy fawn colour, which is now preferred
for sole leather. The hides are next condensed under
a roller, about 6 inches in’ diameter, loaded with from
10 to 13 cwt. : this operation is shown in Fig. 1291.

In some places the hides are hammered on a block,
with awide-faced hammer. In France the hammer is
arranged like the tilt-hammer used in the manufacture







of steel. The leather is now Jim's/zed, and fit for the
market. '
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Fig-1. ~1:291. ROIILING Hrnizs.
Bordier has invented a method of preparing leather
by the use of metallic, or earthy, instead of vegetable
substances, by means of which it is stated that thick
sole leather of durable quality may be prepared in a
remarkably short time. After washing, unhairing,
and swelling the hides, they are submitted to the
action of the metallic solution; this consists of the
sub-sulphate of the peroxide of iron, or sulphuric
acid and peroxide of iron, the latter being in excess.
One method of preparing the solution is as follows :-.—
2 cwt. of bruised copperas are dissolved in 15 gallons
of boiling water, in a copper boiler. The liquor is
run off into a shallow underback, of the capacity of
4A: gallons, and then mixed with M lbs. of sulphuric
acid, (sp. gr. 1848.) This is agitated with 4A lbs. of
black oxide of manganese in powder, gradually added.
The agitation is continued until gas ceases to be dis-
engaged, and afterwards at intervals until cold. The
solution is then diluted with water to any strength
required. The hides and skins digested in this liquor
gradually become impregnated throughout with an
insoluble sub-sulphate of peroxide of iron, while free
sulphuric acid, sulphate of manganese, and a little
proto-sulphate of iron, or copperas, remain in the
liquor. In from 6 to 8 days for hides, and 3 to 4
for skins, the animal fibre is rendered completely im-
putrescible, and a leather is produced as impermeable
to water as that tanned by the ordinary method. The
finishing processes are similar.
For certain special purposes the hides are split
into two portions, after having been immersed in a
weak ooze for 10 or 14 days. Each half is then
tanned separately, and the upper, or grain half, is
used for covering the roof and sides of broughams
and other carriages, the flesh half is used for making
enamelled leather for shoes, &c. The splitting
mac/zine shown in section and elevation, Figs. 1292,
1293, consists of a mahogany cylinder or drum, 1) 1),
6 feet in length, and It feet in diameter. A slot
136
LEATHER.
shown at 20 runs the whole length of the cylinder; in
this slot the tail end of the hide is fastened by small
wooden wedges so. The knife is is a plate of steel
about i- inch thick, and of the same length as the
cylinder. It is attached by means of screws ss, to
' the bottom of a firm cast-iron carriage o; s’ s’ are set-
screws for setting the edge of the knife straight.
A quick alternate motion is imparted to the carriage

by means of a crank 18. While the knife vibrates
rapidly backwards and forwards in a plane parallel
to the axis A of the drum 1), the drum is made to
revolve slowly upon its axis, and drags the hide with
it. The hide is kept flat to the cylinder by means of
the governor e, which is a bent thin plate of steel,
extending the whole length of the knife and in front
of it, and by its pressure, which it receives from a



Fig. 1292.
weighted lever, smoothes out all wrinkles. In fact,
the cylinder drags the hide under the governor, which
acts similarly to a sZz'e/eer, although it is quite
stationary. As the hide b is split, one half j; which
is the split flesh side, passes over the knife; the other
half, or the split grain side g, continues to adhere to
the drum. A screw at I, at each end of the drum, is
used to vary the thickness of the split; the screw
acts upon a lever L’ Z, which, by means of a pin 10,
raises or depresses the axis of the cylinder, and con-
sequently diminishes or increases the thickness of the
split grain side of‘ the hide. Fig. 1294.1 represents the
appearance of the machine with the men superintend
ing the operation.




its’: ‘ ' '
ll _, Ru 1' ‘ I



Fig. 1294. HIDE-SPLITTING- MACHINE.
In concluding this notice of the tanning of thick
. leather, we must refer to the methods of disposing of
the spent bark, a considerable quantity of which is
produced in every large tan yard. It is formed into
cakes by pressure in iron moulds, and sold in London

ELEVATION AND SECTION OF HIDE-SPLITTING MACHINE.

\
Fig. 1293.
as a cheap fuel, under the name of way“. It also
supplies the place of the more expensive article straw,
which is often thrown down in the streets of London,
opposite the houses of sick persons, for the purpose
of deadening the noise of carriages. It is also used for
forming hot-beds ; when collected in a heap, it ferm ents
slowly, and forms a fine vegetable mould. Most of
the pine apples of this country are grown in a com-
post, into which the spent bark largely enters. After
having served its purpose in the hot—bed, it is used as
a manure by the farmer. At the tan-yard of Messrs.
Hepburn, (where the Editor has received much assist-
ance in the preparation of this article,) steam-power
is used, and the spent bark is employed as fuel in
raising the steam, for which purpose the bark, arranged
in layers between iron plates in a large case, is sub-
mitted to the action of a hydrostatic press, whereby
the moisture is expelled, and solid cakes are pro-
duced, which make good fuel. The liquid pressed
out by such powerful means must be rich in alkaline
matter, and we have no doubt that if collected and
properly treated, a good crop of potash salts might be
obtained, the waste heat of the boiler being employed
in the evaporation.
Sne'rron V.—-Cunnx1_ne.
The rough skin of leather is transferred from the
tanner to the currier, who, by a series of mechanical
operations, transforms it into a smooth, shining,
pliable skin, adapted to the purposes of the shoe-
maker, the coach-maker, the harness-maker, &c. We
will trace the operations upon a tanned calf-skin.
The skin is first soaked inwater to make it pliable;
then taken to the beam, and shaved on the rough
flesh side, whereby its thickness is considerably
reduced, and the uneven and unequal surface brought
to a tolerably smooth and even one. The beam, Fig.
1295, consists of a strong frame of wood, supporting
a stout plank, faced with lignum vitae, and made very
smooth; this plank can be set at a greater or less
LEATHER.
137
inclination, and sometimes it is permanently fixed in
an upright position. The knife, Fig. 1296, No. 1,
which is double-edged, is a stout rectangular blade,
about twelve inches long by five wide; but the width
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varies according to the purpose intended. At one
end is a straight handle, and at the other a cross
handle, in the direction of the plane of the blade.
The edge of the knife is brought up by means of a
Whetstone, and a wire edge is afterwards produced
by the tool No. 6, and constantly preserved by means
of a steel wire, No. 7, which the beam-man holds
between his fingers while using the knife. The skin
THE BEAM.

Fig. 1296. cunnrnn’s TOOLS.
2. Crippler.
4. Glass slicker.
6. 7. Steels for beam knife.
8. Brush.
being thrown upon the plank, the man presses his
body against the skin, to prevent it from slipping;
and holding the knife by its two handles, and nearly
perpendicular to the leather, he shaves off from the
thick parts, and, after every shaving, or two or three
shavings, passes a fold between his fingers, and thus
1. Beam knife.
3. Raising board.
5. Steel slicker.

ascertains the state of the skin with respect to even-
ness. When sufiiciently reduced by shaving, the skin
is again tln‘own into cold water, scoured, and extended.
For this purpose it is placed upon a large table of
mahogany or stone, to which the flesh side of the
wet skin adheres, and is worked with a tool called the
stretching-iron, No. 5 ; this is a flat rectangular piece
of iron, copper, or smooth hard stone, fixed in a handle,
with the corners rounded off to prevent injury to the
leather; the workman holds this tool with both hands,
and, using plenty of water, scrapes the surface with
a very strong pressure, especially at those parts where
lumps and inequalities appear. By the continued
action of this tool the leather is extended or stretched,
while at the same time the bloom is brought to the
surface.
When the skin is thoroughly cleansed, and all the
superfluous moisture has been slicked out, the process
of stafiing, or dahhz'ng (probably a corruption of danh-
any), is performed. Both sides of the skin, but chiefly
the flesh side, are smeared or daubed with a mixture
of cod-oil and tallow, which is then well rubbed in by
means of a brush, or a piece of old sheep-skin with
the wool on. The skin is then hung up in a loft to
dry; but as the water only evaporates, the greasy
substances sink deep into the pores of the leather.
In very moist weather the skins are stove-dried.
When the skin is sufficiently dry, it is hoarded,
that is, worked with an instrument called the pommel,
or graining board, No. 2. The object of this is to
bring up the grain, that is, to give the leather a
granular appearance, and also to make it supple. The
pommel is a piece of very hard wood, furnished with
a strap on the upper side, for the insertion of the
hand,1 and grooved (like a crimping board), on the
under side, which is convex. The leather is folded
with the grain side in contact, and rubbed strongly
on the flesh side with the pommel; this part of the
process is called grain/tag. It is then extended and
rubbed on the grain side ; this is called hraz'sz'ng. The
skin is next taken to the beam and whitened, that is,
a knife with a very fine edge is passed lightly over
it, whereby the .flesh side is thoroughly cleaned and
brought to a fit state for waaz'ng,--a process which is
never performed until the skin is required for im-
mediate sale; for, at this part of the process, the
currier stores his skins, because they are brought to
that state (technically called finished rasset) in which
they can be best preserved. Previous to waxing,
the skin is boarded a second time.
the process of waxing consists in laying on the
colour, or blacking, which is composed of oil, lamp-
black, and tallow; the colour is rubbed in thoroughly
on the flesh side, by means of a hard brush; it is
then hZac/c-sz'zed ,- that is, a coat of stiff size and
tallow is laid on with a soft brush or a sponge, and
well rubbed with a glass of the same shape as a
slz'eher ,- and lastly it receives its final gloss from a
little thin size laid on with a sponge. The skin of
leather now curried is called hZach 0n the flesh, or
(1) Hence the origin of the word pommel, from the French
paumelle, because it clothes the palm of the hand.
The first part of‘
138
LEATHER.
waxed, in contradistinction to leather which is' curried.
on the hair or grain side, called bide/c on the grain ,-
and which is chiefly used for the upper leathers of
ladies’ shoes; the former, or ' waxed leather, being
employed for the upper leathers of men’s boots and
shoes. '
The processes for preparing leather to be blacked
on the grain side are' similar to those already de-
scribed, until- we come to' the process of waxing.
Coppems water, i or iron Zigzior, that is, sulphate of
iron dissolved in clean water, or in the water from
the tank in which the skins have been soaked, is
applied to the grain side of the skin while wet. The
iron unites 'with the gallic acid of the tan, and thus
produces an ink dye; the ‘skin is then rubbed over
with a brush dipped in stale urine, and when this is
dry the stuffing is' applied; it is‘ rubbed over with
copperas water on the grain side until it is quite
black. The grain is then raised, and when quite dry,
the skin is whitened, bruised again, and grained in
two or three ways; a mixture of oil and tallow is
then applied to the grain side, and the currying
process is complete.
Snorrou VL—Pnnrnnxrron or THIN LEATHER.1
In addition to the tan-yard, properly so called,
where the thickest and largest skins of leather are
made, there are other establishments which contribute
extensively to the immense demand for thin leathers;
such as white and dyed leather for gloves, morocco of
various *colours and qualities for coach-lining, book-
binding, pocket books, 850., being an imitation of that
prepared in Morocco, and other parts of North Africa‘;
9'06672 for. slippers, &c.; a thin leather called s/aioer,
used for hat-linings, and a number of other purposes;
and, lastly, sizam‘oy, or wash-leather.
Of all these varieties, ‘white leather alone is not
tanned, but-tawed. The difference between the two
processes is, that the gelatinous tissue is combined
with tannin in the one case; and in the other, with
something which it imbibes from alum and salt, pro-
bably alumina. But, for either process, certain
preparations are necessary, whereby hair, wool,_grease,'
&c., are removed, and the skin, thoroughly cleansed,
is reduced to the state of simple membrane, called
pelt‘. . -
The preparatory steps vary, according as the skin
is covered with wool, or short hair; the one being a
valuable commodity, and the other comparatively
worthless, its chief use being to mix with mortar.
The hair of kid and goat skins &c. is detached by
immersing the skins in lime, as already described;
but as this plan ' would injure the wool, a different
method is adopted. The wool is usually detached
from sheepéskins before they arrive at the tawers.
This is done by the great dealers in sheep-skins,
called fillsmoizgers ,- they receive the skins from
certain factors, or salesmen, in the skin-market, by
whom they are procured ‘from the butchers. The
lamb-skins ' of Italy‘ are imported in casks with the

(1) This and the previous Section are abridged from the Editor’s
work on the “ Useful Arts and Manufactures of Great Britain.”

wool on, so that the tawer adopts a process for
removing it similar to that employed by the fell-
monger. They are first cleansed in water, then
scraped on the flesh side, and next hung up in con--
siderable numbers, in the smoke-house already alluded
to, where they are awarded—that is, putrefactive
fermentation soon commences, a thick filthy slime
appears on the surface, and the effect of this is so to
loosen the wool, that it can be pulled off easily. Care
and judgment are required in regulating the fermen-
tation of the skins, so that their texture be not
destroyed. When the wool is removed, the fatty
matters are got rid of by a hydrostatic press; a large
number of skins being piled up, a considerable quantity
of fat is expressed. The skins are then worked at
the beam; projecting flaps and rough edges are pared
off, and putrefaction is arrested by immersion in lime.
They are first put into a nearly exhausted lime-pit,
and afterwards into a stronger one, and are frequently
worked about with poles. When taken out they are
well worked at the beam to get rid of a portion of
the lime; and are then immersed in a fermenting
mixture of dog’s or pigeon’s dung, if the skins are to
be tanned, and of bran and water if they are to be
tawed. During the time that the skins remain in
this mixture, they are occasionally taken out and
worked at the beam, and are lastly washed in pure
water. By such means the pelt becomes a thin
extensible white membrane, and is fit for farming,
iaioiizg, dyeing, oil-dressing, or slidmog/iizg.
Twining wit/i Sumao/a—When goat skins are tanned
with sumach, and then dyed on the grain side, they
form what is called morocco leather; but an inferior
morocco is prepared from sheep-skin. When the
skins are in the state of perfectly clean white pelt,
each skin is sewn by its edges into the form of
a bag, the grain side out; it is then distended
with air, and a mordant of tin, or alum, is applied.
The object of forming the skins into bags is to
expedite the process, and also to ensure a perfectly
equable action of the solution of sumach. If the
colour is to be red, the skins are immersed in a warm
cochineal bath; indigo is used for blue; orchil for
purple, &c.; and they are worked by hand until
uniformly dyed. For other colours the pelt is tanned
before dyeing. The sumaching is conducted in a large
tub, containing a weak and warm solution of sumach.
A stronger solution is made in another vessel, and a
portion of this, together with some sumach leaves, is
poured into the bag, by means of a funnel, through
an opening left for the purpose. This is diluted with
a quantity of the nearly spent solution in the vat;
each skin, after having received its share of the
tanning liquid,.is handed to a man, who blows into it,
and fully distends it: he then ties up the opening,
and throws the skin into the vat. About fifty skins
are treated in this manner; they all float. in the
sumach-tub, and are moved about by manual labour,
or by machinery, during three hours. They are then
taken out, and piled on a sloping shelf by the side of
the vat, the mutual pressure thus produced causing
the sumach to escape slowly through the pores of the
Lniirunii.
139
pelt. The bags are being constantly shifted by a
man, who watches whether the solution escapes from
the seams: if so, he secures them by a few stitches.
They are next transferred to a second vat, containing
a stronger solution than the first; and here they
remain about nine hours, at the end of which time
the tanning is complete. The skins are ripped open,
rinsed, and drained. The colour of the fine red skins
is finished in a weak bath of saffron; and lastly, all
the skins, of whatever colour, are stretched upon a
smooth sloping board, and siruch,-—that is, scraped
and rubbed out, until they become smooth and flat.
Sometimes they are sponged on the grain side with
linseed oil, in order to promote their glossiness in
the subsequent process of currying.
The skins are then removed to a loft, and dried.
In drying they assume a horny texture, and are said
to be in the crust. After this comes the process of
currying, or finishing. The skins are again placed
upon the smooth sloping board, and rubbed several
times with the pommel, and also with a glass ball,
out with smooth sides upon its surface; this polishes
them, and makes them firm and compact. The
grained, or ribbed appearance, peculiar to morocco
leather, is imparted by a ball of box-wood, round the
circumference of which are cut a number of narrow
ridges. This is passed many times over the skin
with a firm pressure, and its effect is not only to
improve the surface of the skin, but also to add to its
pliability and softness.
The preparation of an imitation morocco from
sheep-skins, does not differ essentially from the pro-
cesses just described; but when the skins are in the
state of pelt, they are split; that is, every skin is
divided into two skins of the same size, but, of
course, of only half the thickness of the pelt. This
is effected by means of a shin-splitting machine which
differs in some of its details from that already de-
scribed. It consists of two rollers, the lower one
of solid gun~metal, and the upper one composed of
rings of the same material; these cylinders are made
to rotate slowly, and between them, but not in con-
tact, is a knife, with a sharp cutting edge, to which
a rapid reciprocating motion is imparted. In order
to spiii a skin, a man stands on the side of the
machine, opposite to the knife edge, and upon the
lower or solid roller spreads evenly the end of a
skin or pelt; it is caught up by the rollers, and
dragged forward against the edge of the knife, by
which it is divided; one half going above, and the
other below the plane of the blade. During the
whole of the operation the man continues to adjust
the skin upon the lower roller, the smooth solid
surface of which gives support and stability to the
skin, while the upper roller, being composed of mov-
able rings, adjusts itself to any unevenness of the
membrane. In parts where it is thin, the rings are
depressed; where it is thick, they are elevated;
hence no part escapes the action of the knife, and no
holes are produced in either half. The men are fur-
nished with gloves, to prevent their fingers being
caught up by the rollers. About two minutes are

"occupied in splitting a sheep-skin, during which time
the knife is moved to and fro nearly three thousand
times. When three or four of these machines are at
work in one room, the noise is deafening.
In order to show the precision with which this
beautiful machine works, sheepskins have been split
into three parts of equal size; the grain side being
used for skiver, 850.; the middle for making parch-
ment; while the flesh side was transferred to the
glue~maker. The divided skins, or skivers, are
sumached in a short time, their thinness rendering
the sewing up into bags unnecessary.
Tcicihg.-The preservation of an animal skin, by
means of alum and salt, is called having; and the
object is to employ such materials as will not inter-
fere with the production of a pure white leather. In
all the finer kinds of leather-dressing, the perfect
purity of the pelt is of the utmost importance, for
every particle of dirt, or lime, which is allowed to
remain would appear as a speck or a flaw. The
purity of the water used for rinsing the skins, is also
a point of great importance. At some works, a
supply of distilled water is obtained from the boiler
to the steam-engine, which is made larger than usual
for the purpose.
Kid-skins, for the best kid-leather, and sheep, or
lamb-skins, for an inferior sort, being reduced to the
state of pelt, the first process in tawiug, is to “give
them a feeding” with alum and salt. About 3 pounds
of alum, and 4'1 of salt, are used to 120 middle-sized
skins. The solution, together with the skins, is put
into a drum, or tumbler, to which motion is imparted.
The action of the alum and salt upon the skins is not
well known, but it is supposed that alumina and
gelatine form some definite compound, and that the
salt serves to whiten the skins. After some time
they are taken out, washed in water, and then put
into bran and water, where they are allowed to fer-
ment, till the superfluous alum and salt are removed,
and the thickness produced by them is reduced.
They are next transferred to the drying loft, stretched
on hooks, and left till dry. - They now form a white,
tough, brittle leather; but the glossy finish and soft-
ness of kid is imparted by a dressing, composed of
20 pounds of the finest wheat flour, and the yolks of
eight dozen eggs.1 This paste, diluted with water,
is put into a drum, and the skins are made to rotate
therein, when they so completely imbibe the egg-
liquor, that scarcely anything more than water
remains. This dressing is generally repeated .before
the skins are hung up to dry. But the softness and
elasticity yet remain to be given. The skins are
dipped into pure water, and allowed to remain for a
few minutes; they are then spread out, and worked
upon a board, and etched upon the stretching or soft-
ening iron. This is an iron plate, rounded over at
the edge, mounted upon an upright beam, and fixed
to a heavy plank, well secured in the floor. By these
(I) This egg-dressing is indispensable in the preparation of white
lamb and kid-leather. The eggs used for the purpose are imported
from France and Flanders; and at the time of the writer's visit
to ltIessrs. Bevington’s factory at Bermondsey, they had a stock
of 60,000 eggs pickled in salt.

létO
LEATHER—LEMON, SALTS OF—LENS.
processes the skins are considerably extended in
length, and all hard points and roughnesses removed.
They are finally smoothed with a hot iron, and are
then ready for the glover.
Dressing in Oil, consists in first soaking the skin
in water, and then, by continued hard rubbing, forcing
oil or grease into its pores. As the water evaporates,
the oily matter combines in some way with the fibres
of the skin; renders it permanently soft, and by
keeping out the water prevents it from decay. '
' A process of this kind was formerly applied to the
skin of the Chamois goat, and hence arose the term
cbamovis, sbarnmg, or sbamogeel, as applied to the leather
itself, and slzamoging to the process. As this is the
only kind of leather which, when dyed, will bear
washing without the colour being materially injured,
it is also called wasb-leather.
Wash-leather is prepared, in this country, from
doe’s or sheep’s-skin: and for the inferior kinds, the
flesh side of sheep’s-skin, as obtained from the split
hide, is employed; the other half, or grain side, being
tawed for skiver-leather. Indeed, it is common
always to get rid of the grain before a skin is sha—
Inoyed ; because, by doing so, the extensibility and
softness of the skin are much increased. The grain
is removed by an operation called frizing; that is,
one end of the skin is wrapped over a pole, the’ grain
side uppermost, and then the whole surface is scraped
with a round knife, or with pumice-stone.
The grain being removed, the skins are placed in
bran liquor, and then wrung out; they are afterwards
spread upon a table, sprinkled slightly with oil, and
folded up in balls of four each, and beaten by a number
of heavy wooden hammers in the falling stocks.
The heads of the hammers are covered with copper,
and they work in a kind of trough, in which the skins
are placed. After having been beaten for two or
three hours, according to their texture and the state
of the weather, they are taken out, exposed to the
air, oiled and fulled several times, until all appearance
of greasiness has disappeared. They are next hung
up in a warm room, when a kind of fermentation takes
place, which opens the pores of the skin and promotes
the combination of the oil. They are next scraped
with a blunt concave knife, and scoured in a weak
Warm potash lye, in order to get rid of the uncom-
loined oil. Having been washed in water, they are
gently dried, smoothed, and made supple by the
stretcher iron, or by passing them between rollers.
Snorron VIL—S'rArIsrIcs on LEATHER.
In the year 1830, the duty on ' leather was wholly
repealed; so that there are now no means of ascer-
taining the quantity produced in any one year. The
yearly production, on an average of three years, ending
in 1822, was 418,24i4n026 pounds. In this year the
diaty was diminished from 3d. to led. per pound;
and the average production of the next three years
showed an increase of 30 per cent. The repeal of
the duty and the increase in population have, doubt-
l'ess, increased the consumption of leather to a far"
greater extent. It has been calculated that the

annual production of all sorts of leather, tanned,
tawed, dressed, and curried in Great Britain is about
60,000,000 pounds; the value of which, taking one
quality with another, at ls. 6d. per pound, amounts
to 41,500,000l. It is supposed that the value of the
leather forms only one-third of the finished articles,
so that the ultimate value of the manufacture, in
Great Britain alone, must be 13,500,000l. Some
estimates are even higher than this, and make the
aggregate value of leather goods to exceed18,000,000l.
per annum. “ Nor will this amount appear excessive,”
says Mr. M‘Gulloch, “if we consider that there is
only a very small proportion of the people, however
poor they may be, who do not wear leather shoes or
boots; that the use of leather gloves is general among
all but the labouring classes; and that the harness of
horses used for pleasure, as well as those used for
agricultural and other business operations, is made
with this material, besides an endless variety of things
in daily use, which will suggest themselves to every
one’s mind.” Taking the population of Great Britain
at 21,000,000, and supposing that each individual
spends on an average 88. per annum for shoes and
boots only, the annual outlay for these articles
will be 8,400,000l. Some have supposed that the
value of saddlery, harness, gloves, &c., is, at least,
equal to that of shoes; but this estimate is probably
too high.
In consequence of the odours diffused by tan-yards,
they are generally situated at the outskirts of a town.
During a long period, Bermondsey was the principal
seat of the leather manufacture in England, on account
of the Thames tide-streams affording an abundant
supply of water. Although the Bermondsey manu-
factories are more extensive than ever, tan-yards are
established near most of the towns of this country.
LEMON—SALTS or. This term is incorrectly
applied to the binoxalate of potash, or salt of sorrel,
as it is called in commerce. Large quantities of it
are prepared in Switzerland and the neighbouring
countries from wood sorrel. About 60 or '7 0 lbs. of
the plant, when in full vegetation, yield about 5 oz.
of the crystallized salt. This salt is sometimes used
instead of lemons in making lemonade and flavouring
punch, and hence the term esseniial salt of lemons.
The oxalic acid contained in it oughtto forbid such
a use. This salt unites readily with several of the
earths and with most of the metals, and hence is used
in removing ink-spots and iron-moulds from linen,
one proportional of its acid uniting with the iron, form-
ing a soluble and colourless oxalate of iron.
LENS, a term originally applied to a magnifying-
glass, from leniile, a bean or seed, the shape of which
is somewhat convex on both sides. Opticians now
distinguish six kinds of lenses, three convex and three
concave. The three convex are, l,plan0-eonvea, plane
on one surface and convex on the other: 2, double
banner, or convex on both surfaces : when the radii
are equal, the lens is termed egui-eonnea ,- when one
radius is six times the other, it is called a erossecl
lens: 3, Meniscus, or convex on one side and concave
on the other, the convexity being greater than the
LENS.
141
AA
concavity. All these lenses are thicker in the middle
than at the edges. The concave lenses are, a, plana-
concaoe, or plane on one surface and concave on the
other; 5, doable concave, or concave on both surfaces;
6, coneaoo-conoea, or more concave on one side than
convex on the other. All these lenses are thinner at
the middle than at the edges. The last-named lens

.Zl
Fig. 1297.
of either kind is also called periscopz'o, from o'Korre'cc,
to see, wept, round about, from their giving a larger
field of View than ordinary spectacles.‘ This advan-
tage is of doubtful character, since the spherical
aberration of such lenses exceeds that of other lenses.
The optical properties of lenses will be noticed
under LIGHT. In the present article we propose to
enter into a few particulars respecting the grinding
and polishing of lenses, referring to the article GAST-
ING and FouNnINe, for the methods of casting, grind-
ing, and polishing the specula used for reflecting
telescopes.
When two hard bodies are rubbed or ground toge-
ther there is always a tendency for one of them to be-
come convex and the other concave, and it is by taking
advantage of this tendency that glass is ground into
lenses. It can be proved by certain optical properties
of a well-formed lens, that no part of its surface
deviates by a ten-millionth of an inch from a truly
spherical figure: indeed, surfaces cannot be made so
accurately plane as they can be made convex.
In the grinding of lenses counterpart tools of metal
are used, adjusted to the curvatures of the lenses,
and serving as a medium for applying the grinding
and polishing powders. Each tool consists of a con-
vex and a concave surface, which are first ground
together into shape and thus made to correct each
other’s defects. In preparing one of these tools a
convex and a concave template is first made to the
radius of the required curve. If the radius be large
the templates are cut out of crown glass by cement-
ing a sheet of that material upon a bench, and
mounting a glazier’s diamond upon the end of a light
radius bar: a brad-awl being stuck into the bench
serves to support the other end, the distance from
the diamond to the awl being the radius of the curve.
The glass, being cut by the diamond, is broken in the
line of the cut, by which means concave and convex
edges are formed: these edges are ground by being
rubbed together with a little emery and water with
the pieces in a flat position, one of them being occa
sionally turned over in order to verify the curves.
Templates are more usually formed of sheet brass;
those of large radii being cut with a strong radius-
bar and cutter; whilst those of a few inches radii are
cut in the turning-lathe.
The tool used in making convex lenses is a concave
shell of cast-iron, shown in section Fig. 1298. The

wooden pattern used in casting this shell is carefully
turned to the curve of the template,while a similar shell,
turned to a radius of about ~§lth inch larger than the
template, is used as a foundation for the polisher. A
l
NA‘ @\
Fig. 1299.

Fig. 1298.
convex tool, or runner of cast-iron, Fig. 1299, of about
é-inch less radius than the template, is used as the
support for common glasses, a number of which are
ground together. A pair of brass tools, Fig. 1300,
of the exact curvature of
the templates, are also
prepared and made to fit g g
each other with great <~—’
nicety. The concave half
is used for correcting the
curvature of the lenses
after they have been
roughly shaped in the .
Fig. 1300.
concave shell, Fig. 1298.
The convex half is used for preserving the true shape
of the concave grinding tool and polisher. The screws
at the back of these tools admit of their being fitted to
the lathe mandrel, to be turned to the curvature of the
templates. These screws also serve to secure the tools
to the top of an upright post or pedestal, about 3 feet
high, firmly fixed into the floor, and furnished at the
top with an iron block and a vertical screw. The
brass tools having been turned to the proper curve,
the convex tool is fixed by its screw to the top of the
post; a wooden handle is screwed into the back of
the concave tool, and they are then ground together
with emery and water, or with dry emery distributed
as uniformly as possible by rubbing it level with a
piece of glass of similar curvature, wiping off any
excess from the margin of the tool. The operator
works the concave upon the convex tool with a cir-
cular swinging stroke, and between every few strokes
he moves a little way round the post, the object
being to bring the two surfaces in contact in every
possible position, and to rub them upon each other at
all angles, so as to produce a true spherical figure.
The glass for the lenses is brought into a circular
form by means of shanhs or flat pliers of soft iron,
which do not slip as steel would do. The iron jaws
being applied near the edges of the glass cause it to
crumble away in fragments, and by this shanhz'ng or
nihhlz'ng the glasses are made circular, but they are
left somewhat larger in diameter than is required for
the finished lenses. A small quantity of cement is
then poured upon each glass ; and when this has set,
more is added, until it rises in a hemispherical mass
capacious enough to be grasped with the fingers.1
Each glass is next rough-ground within the. shell,
Fig. 1298, with river sand and water, or coarse emery

(l) The cement is formed by mixing with 14 parts of melted
pitch about 4 parts of sifted wood ashes, the latter serving to re~
duce the adhesiveness of the pitch. If the cement be too hard and
brittle, it may be softened with tallow or hogs’ lard.
1112
LENS.
and water, until the surfaces are brought nearly to
the curve of the' shell. , The shell is placed within a
shallow tray, for the purpose of catching the loose
sand or emery thrown off in the grinding. The glasses
are rubbed with large circular strokes, and when this
rough grinding is completed on one side the glass is
warmed to detach the handle of cement, which, being
attached to the ground side, the other side is similarly
ground. By leaving the edge of equal thickness all
round, the two surfaces are kept tolerably parallel.
All lenses are rough-ground in this way: those of
the best quality are next ground into the correct
shape in the brass tool, and polished one at a time.
For common lenses several are operated on together.
As many as four dozen common spectacle-glasses are
sometimes cemented upon a runner and ground and
polished together; but they mu st be arranged symme-
trically round a central lens, as 7, 13, or 21; or a
group of 4! may form the nucleus, in which case the
numbers are A, 141, 30. Lenses of medium quality
and size are often ground true and polished 7 at a
time. Taking the last case, the method is as fol-
lows :—-The cement at the back of the lenses is
flattened with a hot iron, and the '7 lenses are placed
with the cemented sides upwards in the concave
brass tool, onelens in the centre and the other six at
equal distances around. The iron runner is then
heated and carefully placed upon the backs of the
lenses; the cement softens and adheres firmly to the
iron, which is then cooled with a wet sponge, matters
being so arranged that the spaces between the lenses
are nearly filled up with the cement, but the cement
must not be quite level with the surface of the lenses.
The block of lenses thus formed, Fig. 1299, is screwed
into the post and ground with the concave brass tool,
Fig. 1300, six sizes of washed emery being used in
succession, each finer than the one previously used,
the last size being the fine powder collected after one
hour’s subsidence, and which produces so smooth
a surface as to appear partly like a polish. The
grinding is continued with each size of emery until
all the marks produced by the previous size have been
removed, the whole apparatus being carefully washed
after each application, so as entirely to get rid of one
emery before a finer one is used. The tracing of the
lenses, as it is called, being completed, the polishing
is next proceeded with. The polisher is made by
warming an iron shell; coating it uniformly with
about %-inch thick of melted cement, and then pressing
down upon the cement, by means of the brass convex
tool, a piece of thick woollen cloth with the nap worn
oil’, or seared off with a hot iron. Putty power1 is

(I) The putty powder used by Mr. A. Ross, the optician, is
prepared as follows z—Metallic tin is dissolved in nitro-muriatic
acid, and precipitated from the filtered solution by liquid ammo-
nia, both being largely diluted with water. The peroxide of tin
is washed with plenty of water, collected on a. cloth filter, and
squeezed as dry as possible in new linen cloth : the mass is next
pressed in a screw-press as dry as possible. The lump thus pro-
duced is broken up, dried in the air, and finely levigated on aplate
of glass with an iron spatula, and exposed in a crucible to a low
white heat. Before being heated the powder has but little cutting
properties, but being made anhydrous by heat the particles assume
the form of laniellar crystals, and act with far more energy, yet

then sifted uniformly over the cloth, moistened by
sprinkling water over it, and worked into the cloth
with the brass concave tool. Fresh powder is added,
and the working continued until the surface is quite
level. For small lenses a polisher of kerseymere is
used: this is more readily filled up with the putty
powder than the coarse. woollen cloth. The polisher is
placed upon the block of lenses, fixed on the post,
and worked with wide and narrow elliptical strokes,
the operator continually moving round the post. The
putty powder must not be so wet as to run loose upon
the polisher, nor so dry as to be cut up by the edges
of the lenses. It must be wet enough to take a par~
tially glazed appearance from the action of polishing,
and when entirely glazed a little water must be
sprinkled over it. The pressure must be very
moderate.
The next process is to grind the edges of the lenses
circular, and in order that the axes of the lenses may
coincide with the axis of the tube of the telescope
or other instrument in which they are to be mounted,
the lenses are cemented upon a chuck in the lathe,
and before the cement has set the lathe is made to
revolve, and the reflection of a candle or any fixed
object watched, and the lens adjusted, until the image
appears to be quite stationary notwithstanding the
motion of the lens: the axis of the lens and that of
the mandrel of the lathe are then known to coincide,
and the edge is ground circular with a piece of brass
supplied with emery and water, placed beneath the
lens, and gradually raised by a screw. -
Concave lenses are ground and polished in the
same manner as the convex, only they are fixed in
the concave tools and ground upon the convex, which
is always the lower tool, when several glasses are
worked together.
In the Transactions of the Society of Arts, vol.
xlix., Mr. C. Varley has described a lathe for grinding
and polishing lenses and specula. In this arrange-
ment, the lower tools are not mounted upon a fixed
post, but upon a vertical revolving axis. By this
means the process is considerably expedited, but the
results are less accurate than by the plan already de-
scribed. In the 50th vol. of the same Transactions,
Dr. R. Greene’s machine for grinding and polishing
specula and lenses is also described.
Common lenses, which are produced in large quan-
tities in manufactories, are also ground and polished
by machinery. “ The block of lenses is mounted
upon a slowly revolving axis, placed vertically, and
the upper tool has an eccentric motion, given to it by
means of a small crank, fixed on the lower end of a
second vertical axis, placed a little on one side of the
central line of the lower axis. A pin fixed in the
centre of the back of the upper grinding tool, enters
a socket in the crank, and the revolution of the latter
causes the upper tool to describe small circles, which,
combined with the slow revolution of the block of
without scratching, than any of the ordinary polishing powders.
The coarser particles are separated by washing over. A little
crocus is added by way' of colouring matter, which makes it easier
to ascertain the quantity of powder remaining on the polishing
tool. '

LENS—LEI’IDOLITE—LEUCITE—LEVEL.
1413
lenses, causes every point of the grinder to describe
epicycloids upon the surface of the lenses, much the
same as in the circular strokes employed in grinding
lenses by hand. The radius of the crank admits of
adjustment, to give various degrees of eccentricity
to the upper tool, and the pressure is regulated either
by a spring, or by adjusting the weight of the
grinder.”
The best lenses for object glasses of telescopes, are
ground and polished singly by hand. They are
polished with putty powder upon thick lutestring silk
cut to the width of about %ths the diameter of the lens :
this is stretched across the middle of the brass tool,
and the lens is rubbed backwards and forwards in
straight lines along the silk, the lens being continually
twisted round in the hand.
In making the object glasses of achromatic tele-
scopes, it is of importance to be able to measure
accurately the radii of curvature of the lenses, which
are first tried experimentally, and then made as nearly
as possible to the radii obtained by calculation, so as
to correct the chromatic and spherical aberration.
In the Transactions of the Society of Arts, vol. liii.,
Mr. A. Ross has described an instrument called a
sphercomeier, for measuring the curvature of the
grinding tools.1
Small microscopic lenses, varying from ,1- to froth of
an inch in diameter, are also ground and polished singly,
the radius of curvatiue being too small to allow of a
number being grouped together. “ The templates
are made as small discs of steel with slender stems
turned in the lathe. For lenses, the radii of whose
curvature are 5, 10, or 20 hundredths of an inch, the
diameters of the discs are 10, 20, or 4:0 hundredths.
They are made with square edges, and when hardened,
are applied diametrically, as the finishing tools for
turning the small metal cups or concave grinding
tools. For measuring the diameters of the discs they
are applied either in the sector gauge, or one of the
sliding gauges often used for measuring the diameter
of wire, and graduated decimally for reading the width
of the opening to the 150th or 10100 th of an inch.
The cups, when turned, are charged with emery, and
put in rapid revolution in the lathe, which, for. these
minute lenses, is in general very small, and worked
with the drill how. The lens is cemented with shell~
lac, upon a small wooden stick, and held against the
grinding tool with a continual change of angle, the
end of the stick being moved in the arc of a circle,
while it is, at the same time, twisted on its axis.”
The grinding is performed with the same succession
of emeries as is used for the larger lenses. The
polishing is done with bees’-wax hardened with fine
crocus, of such a consistence as to assume the form
of the lens with moderate pressure, and hard enough
to retain. the figure during the polishing. The brass
cups used in the polishing are turned in the lathe of


(I) This instrument is also figured and described in the third
vol. of Holtzapti‘el’s Mechanical Manipulation, to which Mr. Ross
contributed much of the valuable and interesting information re-
specting the manufacture of lenses. Gill's Technical Repository
also contains some interesting details on the subject.

a little larger radius than the grinding tool, and the
surface is roughened for holding the wax, which is
poured into the heated tool, and when cold, moulded
into shape with a convex tool, or turned in the lathe
first, with a thin scraping tool, and then with a cir~
cular disc, as in the case of the grinding tool. In
polishing the lens, the wax is kept wet with fine cro-
cus and water applied with a feather. The lenses are
separated from the runner or handle by warming them,
so as to soften the shell-lac ; and the last particles
of cement are washed off by means of spirits of wine.
Lenses for, spectacles are formed out of Brazilian
pebbles of transparent, colourless quartz. The stone
is cut into slices by the lapidary, then snipped into
the form of the lenses, and ground and polished by
the methods above described.
In fitting lenses into the tubes of optical instru-
ments, the brass
cells or rings are
turned with a
slight excess of
metal projecting.
as at a, Fig. 1301: the glass being put into its
place, this thin edge is then curled over the glass
as at h by means of a burnisher applied while the
ring is revolving in the lathe.
LEPIDOLITE, also called lilac, or lilhicc mica,
occurs massive, and is generally composed of small
thin flexible scales, translucent and sometimes hexa—
gonal. Its fracture is uneven; its colour pearl grey,
peach-blossom, rose and purple, red and greenish.
Sp. gr. 2'85. It is found in granite, near Itosena, in
Moravia, at Perm in Russia, at the Isle of Uton in
Sweden, and in North America. The red variety
from Moravia yielded to Dr. Turner, silica 50'35,
alumina 28'30, potash 9'041, lithia 4149, oxide of
manganese 1'23, fluoric acid and water, 5'20.
LEUCITE is found in lava, in trapezoidal crystals
and massive. The primary form is a cube: the frac-
ture conchoidal, undulating, shining. Hardness 5'5
to 6. Colour yellowish, greyish, or reddish white.
Streak white. Lustre, vitreous. Sp. gr. 2483. The
massivevariety is amorphous and granular: reduced
to powder it renders vegetable blues green. A speci-
men from Albano, analysed by Arfwedson, yielded
silica 56'10, alumina 23'10, potash 21'15, oxide of
iron 0%. , _
LEVEL, an instrument for finding a line or sur-
face exactly level, or such as shall be everywhere
parallel to the true horizon, or at right angles to the
plumb-line, or direction of gravity. It also enables
the surveyor to find the difference between the
heights of two or more places on the surface of the
earth, as in the operation of LsvnLLrNs.
For the attainment of these objects, various instru-
ments have been contrived, the action of most of which
depends on gravitation._ The plumb-level, described
under BBICKLAYING, is constructed in various forms,
and under different names; but the principle is the
same in all, viz. to attach a thread and plummet to
the upper part of a board, or flat frame of _wood or
metal, so that, when the thread, hanging freely, coin-



Fly. 1301.
14:41
LEVEL.
cides with a fiducial line marked on the frame, it is
at right angles to the base of the instrument, and the
surface to which the base is applied must be level;
but if the thread declines from the mark, the surface
is lower on one side than on the other. In nice ope-
rations, the vibrations of the lead are troublesome:
but these may to a great extent be prevented by im-
mersing the lead in a vessel containing water or
other liquid; or the plummet may be enclosed in a
glass cover, to protect it from the wind; and sights,
and a telescope may be added, applying it upon or
parallel to the base, when it is required to take the
level of distant
objects. The Ar-
tillerg Fool-level,
Fig. 1302, con-
sists of two legs
or branches of
equal lengths,
and at their
juncture is a small hole, from which hangs a thread
and plummet, playing on a quadrant, which is divided
on each side into 415° from the middle. When the
ends of the two branches are placed on a surface,


Fig. 1302.
and the thread hangs perpendicularly over the middle.
division, the plane must be level. By placing the
two ends on a piece of artillery, the latter can be
raised to any proposed angle as indicated by the plum-
met. The Gunner’s level, for levelling cannons and
mortars, is atriangular
brass plate, Fig. 1303,
about four inches high,
at the bottom of which
is an arc, graduated
into 415°; on the centre
from which the are
was struck a piece of
brass a 13 turns, and
may be fixed by a
screw: the lower end
B serves for a plum-
met and index to show
the various degrees of
elevation of pieces of artillery. The instrument has
a brass foot to set upon cannons or mortars, so
that when they are horizontal, the instrument is per-
pendicular. The foot is placed on the piece to be
elevated, so that the point of the plummet may fall
on the proper degree : this is called levelling ibe piece.
The Balance-level is suspended as a pendulum: it is
furnished with sights, which, when the instrument
hangs at rest, show the line of level: a telescope may
be used to assist the observation. There are various
forms of this level, which has not much sensibility,
and is very liable to be disturbed by wind. Mariolle’s
Reflecting leve is a long surface of water, made so
as to reflect to the eye an inverted image of the
obj ect; and the point where the two objects appear
to meet is on a level with the place where the sur-
face of the water is found. A reflecting level by Gas-
sini is a steel mirror, placed a little before the object
glass of a telescope suspended perpendicularly. The



mirror makes an angle of 45° with the telescope when
the perpendicular line of the telescope is converted
into a horizontal line, which is identical with the line
of level. The water-level shows the horizontal line
by means of a surface of water in a trough; or it
may be made with two cups, fitted to the two ends
of a pipe, 3 or a feet long, and about 1 inch in dia-
meter. Water is poured into the cups, so as to fill
the tube and part of the cups: the pipe is movable
on its stand by means of a ball-and-socket joint, and
it will be evident that the surface of the liquid in
the two cups will always be in the line of level.
A glass cylinder, 3 or 4! inches long, is sometimes
attached to each end of the pipe instead of a cup, and
a coloured liquid, water or mercury, being poured into
the pipe, rises into the cylinders, and thus determines
the line of level. This form of instrument is conve-
nient for levelling at small distances. The air-level
marks the line of level by means of a bubble of air
enclosed with a liquid in a glass tube curved slightly
upwards, the two ends of the tube being hermetically
sealed. The tube is commonly secured in a brass bed
or case, with an opening in the middle through which
the bubble of air may be observed, and this brass bed
is fixed to a brass or other plane, which being placed
on any given surface, if the bubble rests at a certain
mark in the middle of the tube such surface is level;
if not level _
the bubble '‘ b‘
will rise to- F _ >
end. An in- I ‘
strument of
this kind,
with sights,
is shown in
Fig. 1304.
The air—level
LL’ is about
8 inches long, and 7 or 8 lines in diameter: it is set
in a brass bed it" with an opening in the middle 1. L .
The bed is attached to a straight ruler about 12 inches
long, and at each end is a sight, ss’, exactly perpen-
dicular to the tube, and of equal height. Each sight
has a square hole subdivided by a cross of thin brass,
in the middle of which is a very small hole, through
which a point on a level with the instrument is to be
observed. The brass bed is attached to the ruler by
means of screws, one of which, a, serves to raise or
depress the tube so as to bring it to a level. The top
of the ball and socket is fastened to a small ruler,
one end of which is fastened with a screw to the large
ruler, and at the other end is a screw,b for slightly
raising and depressing the'instrument when nearly
level.
The spirit level is the most accurate levelling
instrument: it was invented by Sisson, and greatly
improved by Ramsden, Troughton, and Gravatt. It
consists essentially of a glass tube nearly filled with
spirits of wine, and hermetically sealed at both ends,
so that when held with its axis in a horizontal
position the bubble of air is in contact with the


\._.~»>_~-\
_, a . -\¢?,‘_;f‘-1*~'\
LEVEL.
_145
upper surface. If the tube be perfectly cylindrical,
the exact horizontality of its surface may be ascer-
tained by the extremities of the air-bubble being at
equal distances from the middle point in the length
of the glass. -
At first view nothing would appear more simple
than the construction of such a tube. There are, how-
ever, numerous difficulties and sources of error which
have been investigated by Mr. Nixon of Leeds, whose
papers on this subject in the Philosophical Magazine
for 1827, 1829, and 1831 will repay a careful perusal.
The following remarks on the theory and construction
, of spirit levels are abridged from an article on the
subject contained in the Z/hzcyclopeedia Britannica.
When a plummet or apendulum vibrates freely in a
circular arc, the tendency of gravity to bring it to
the resting position is everywhere as the sine of the
angular distance from that position. Now if the
bubble in the spirit-level move in a circle, it is
obviously acted on by a force precisely similar to
that which gravity exerts upon the plummet; and
therefore it would seem that a spirit-level should
measure small angles with the same accuracy as a
sector whose radius is equal to that of the curvature
of the glass tube, or a plumb-line of the same length;
but there are some causes which diminish its accuracy.
When the bubble of air has been brought to the
middle of the glass tube, and when the tube, after
being deranged, is restored to the very same position,
we cannot be sure that the bubble of air will return
to the very middle of the tube. This irregularity is
produced by the friction of the included liquid against
the sides of the tube, and depends on the magnitude
of the bubble and the quantity of liquid. In a good
level, where the bubble moves about five lines for a
minute of inclination, this uncertainty does not
exceed half a line, which may be ascertained by
pointing the telescope to any object. The coinci-
dence of a plumb-lime with a particular mark will, on
account of the insensible oscillation of the thread,
leave about double the uncertainty which is left by
the index of a sector, and which may be estimated at
about a hundredth of a line. Levels are commonly
made of glass tubes in the state in which they are
obtained from the glass-house. Of these, the
straightest and most regular are selected and ex-
amined, by filling them nearly with spirit of wine,
and ascertaining by trial that side at which the
bubble moves most regularly, by equal inclinations of
the instrument upon a stage called the hahhle-trier,
which is provided with a micrometer screw for that
purpose. The most regular side is chosen for the
upper part of the instrument, the others being of
little consequence to its perfection. Spirit of wine
is used, because if pure it does not freeze at natural
temperatures, and is more fluid than water. Some-
times, indeed, though very rarely, ether is employed.
The tube and the bubble must be of considerable
length. The longer the bubble, the more sensible it
is to a small inclination. A very small bubble is
scarcely sensible; it appears as if attached to the
glass, and moves but slowly. In the use of a level
voL. II.

of this kind "constructed by Langlois, it was remarked,
that when it was properly set in the cool of the
morning, it was no longer correct in the middle of
the day, or when the weather became hot; and that
when it was again rectified for the middle of the
day, it became false in the evening, after the heat
had diminished. The bubble was much longer in
cold than in hot weather, and when longest it was
too much so, and could not be kept in the middle of
the tube, but stood a little on the one or the other
side, though the inclination was precisely the same.
These defects were small, and such as claim the
notice of careful observers only; but they appeared
of too much consequence not to produce a wish to
remedy them. It was observed that they arose from
inequalities in the interior surface of the tube; and
by examining a great number of tubes, selected for
levels of the same kind, there was reason to conclude
that all these levels would have more or less of the
same defects, because there was not a tube of a
regular figure within. They were at best no other-
wise cylindrical than plates of glass can be said to be
plane before they are ground. The irregularities
were easily discernible. It was therefore concluded
‘that it would be advisable to grind the inner surfaces
of the tubes, and give them a regular cylindrical, or
rather spindle form, of which the two opposite sides
should correspond with portions of circles of very
long radius. To accomplish this, a rod of iron was
taken of twice the length of the glass tube, and on
the middle of this rod was fixed a stout tube of brass
of the same length as the tube of glass and nearly
filling the bore. The rod was fixed between the
centres of a lathe, and the glass gently rubbed on
the brass cylinder, with fine emery and water, causing
it to move through its whole length. The glass was
held by the middle, that it might be equally ground,
and was from time to time shifted on its axis, as was
also the brass cylinder, in order that the wear might
be everywhere alike. The operation had scarcely
commenced before the tube broke; and several others
experienced the same misfortune, though they had
been well annealed. It was supposed that the emery
which became fixed in the brass might contribute to
split the glass, each grain continuing its impression
with the same point, in a straight line, and in some
instances might be disposed to cut the glass as a
diamond would do. Yet it is curious that some
artists find a wooden cylinder to suit pretty well,
probably because it does not hold the emery so
firmly as brass does. But when a cylinder of glass
was substituted instead of the brass, the emery, roll-
ing on the surface of the glass, instead of fixing itself,
had better success; so that the tube and cylinder
touched each other through their whole length. The
same operation was continued, using finer and finer
emery to smooth the tube, and prepare: it for polish-
ing ; after which the tube and cylinder having been
well washed, thin paper was pasted round the cylinder,
and very equally covered with a small quantity of
Venice tripoli. The tube was then replaced and
rubbed as before, till it had acquired a polish.
L
146
LEVEL.
A level thus ground may be either of the proper
sensibility, or be too much or too little sensible. It
will be too sluggish, if, before grinding, exclusive of
the inequalities of the tube, its diameter in the middle
of the length should much exceed the diameter of
the extremities; or it will be too sensible if this
diameter should not sufliciently exceed the other;
or, lastly, if the middle diameter be smaller than that
of the extremes, the bubble will be incapable of con-
tinuing in the middle, but will, in every case, either
‘run to one or the other end, or be divided into two
parts.
To correct these defects, and to give the instru-
ment the required degree of perfection, it is proper
to examine its figure before the grinding is entirely
finished. For this purpose, after cleaning it Well, a
sulficient quantity of spirit of wine must be put into
it, and secured by a cork at each end. The tube
must then be placed on the forks or Y’s of a bubble
trier, and its sensibility, or the magnitude and
regularity of the space run over by the bubble, by
equal changes of the micrometer screw, must be
ascertained. If the runs or spaces passed over he
too great, they may be rendered smaller by grinding
the tube on a short cylinder; but if they be too short
they may, on the contrary, be enlarged, by grinding
on a longer cylinder. It is necessary, therefore, to
be provided with a number of these cylinders of the
same diameter, but of different lengths, which it is
advisable to bring to a first figure, by grinding them
in a hollow half cylinder of brass. By means of these
it will be easy to regulate the tube of the level to any
required degree of sensibility, after which the tube
may be very quickly smoothed and polished.
A level thus ground was one'foot in length, and
so was the cylinder on which it was first worked.
When finished it was found to be too sensible. It
was therefore worked on another cylinder between
nine and ten inches long, which diminished its sensi—
bility so far, that the bubble, which was 9 inches and
41 lines long, at the temperature of 68° Fahr, was
carried from the middle of the tube exactly one‘line
for every second of inclination. This sensibility was
thought suflicient; but if greater is required, it may
be obtained by the process here described.
It may be remarked, that a glass tube is very
subject to be split by grinding its inner surface; the
same tube will not be endangered by grinding its
external surface, even with coarse emery; and when
once the polish of the inside is ground off, the danger
is over, and coarser emery may be used with safety.
Thick glass is more subject to this misfortune than
thinner. The coarsest emery used in grinding the
tube here spoken of was sufficiently fine to employ
one minute in descending three inches in water.
‘Spirit ‘levels are known by various names. The
Y level is so called from the supports in which the
telescope rests, resembling in shape the letter Y:
this is the oldest construction of the spirit level now
in use. Trougfilazz’s improved level is a more perfect
and- stable instrument than the former. This has
been modified by Mr. Gravatt in what is called the

Bumpy level, represented in Fig. 1305-. Its optical
advantages consist in adapting to the telescope an
object glass of large aperture and short focal length,
for the purpose of obtaining the light and power of a
large instrument, without the inconvenience of its

GRAVATT’S LEVEL.
Fig. 1305.
length. AA is the telescope with a diaphragm and
cross wires : the internal tube or slide which carries
the eye-piece, &c. is nearly equal in length to the
external or telescope .tube, which being sprung at its
aperture secures to the slide and eye-piece a steady
and parallel motion when adjusting for distinct vision
of a distant object by the milled head 1?. B, is the
spirit level attached to two rings passing round the
telescope, bythe capstan headed screws 0 c, which are
the means of adjusting the air bubble of the level for
parallelism with the line of collimation. 1) is a small
spirit level placed across the telescope at right angles
to the principal level 0 o: it is of use in setting the
instrument up approximately level by means of the
legs only, which saves time and also the wear of the
parallel plate screws. Having directed the sight to
the staff and adjusted for distinct vision, the two
levels at once show which of the screws require
touching to perfect the level before noting the obser-
vation. A mirror mounted by a hinge-joint on a
spring piece of brass, is placed on the telescope at E:
its use is to reflect the image of one end of the air
bubble in the principal level to the eye, so that the
observer, having carefully adjusted his level, can
while reading the staff see that the instrument
retains its position, by noticing if the reflected end
of the air bubble coincide with the proper division of
the small scale fixed on the bubble tube. The
parallel plates and screws are shown at e c. It is
convenient for one of the screws to rest in a notch
or Y fixed on the lower plate exactly over one of the
legs, so that by giving motion to that leg only after
the other two are fixed in the ground, the instrument
can be set up so nearly level that a very small motion
of the parallel plate-screws will be required to perfect
it. E 11 are’ two capstan screws, which are used for
making the spirit bubble maintain a central position
in its tube while the instrument is turned completely
round on the staff-head. -I is the compass, which
contains either a floating card or‘ graduated silver
ring mounted on the needle, the divisions of which
LEVEL—LEVELLING.
1417
are magnified by a lens K, which slides in a socket,
not shown in the figure, affording the means of read-
ing to 10 minutes of a degree; the rapid vibrations
of the card or needle are checked and speedily brought
to rest by a contrivance, in which a spiral spring is
moved by a milled-headed screw; this also serves to
clamp the needle when not in use.
The wire plate or diaphragm in the above instru-
ment-is usually furnished with three threads, two of
them vertical, between which the station-staff may be
seen, and the third by which the observation is made
is placed horizontally, (see Fig. 1307 5) or a pearl
micrometer scale may be fixed perpendicularly on the
diaphragm instead of wires. This consists of a fine
slip of pearl with straight edges, one of which is
divided into a number of parts, generally hundredths
or two-hundredths of an inch, and is so fixed that
the divided edge intersects the lime 0f collimation}
the central division indicating the point upon the staff
where the observed level falls.
Before the instrument is used in the ground, it
requires certain corrections. Mr. Gravatt’s instructions
are as follows :——Let three pickets be driven into the
ground, in a line, and at equal distances from one
another, and let the spirit level be set up successively
in the middle between the first and second and between
the second and third pickets: then, by means of the
screws, having adjusted the spirit tube so that the
bubble of air may retain the same place while the
telescope is turned round on the vertical axis, direct
the object end of the telescope successively to the
station-staves held up on the different pickets, read
the several heights, and take the differences between
those on the first and second and on the second and
third staff. Now, the staves being at equal distances
from the instrument, it is obvious that any error in
the line of collimation, or from the spirit tube not
being parallel to that line, will be destroyed, and the
differences between the readings on the staves are
the differences in the levels of the heads of the
pickets; but unless the instruments are perfect, this
will not be the case if the instrument be set up at
any point which is unequally distant from all the
pickets; therefore, from such point direct the tele-
scope to the staves, and take the differences of the
readings as before. On comparing these differences
with the former, a want of agreement will prove that
the intersection of the wires is not in the optical
axis, and the error may be corrected by means of the
parallel plate screws. After the agreement has been
‘obtained, should the bubble of air not stand in the
middle of the tube, it may be brought to that position
by a screw at one extremity of the case, and the
instrument is then completely adjusted.
For further particulars on this subject we must
refer to Mr. Simms’s Treatise _ on Mathematical
Instruments.
LEVELLING is the art of determining the heights
or depressions of points on the ground, with respect '
to a spherical or spheroidal surface, such as the earth,

(I) The line which joins the centres of an the lenses, such as
x B, Fig. 1297.

or when the extent of ground is inconsiderable, with
respect to a horizontal plane passing through some
given point on the ground. In extensive operations
of this kind undertaken by the astronomer, the figure
of the earth must be taken into account; but when
the object is to determine the profile of the ground,
for a canal or a railroad, it is sufiicient to consider the
surface to which the points are referred, as that of a
sphere. The civil engineer, therefore, interprets the
word levelling rather as the difference between two
planes or heights than the attainment of a perfectly
horizontal surface: and his object in the operation is
generally to ascertain how much ground must be
elevated or removed to assist the flow of water, or
the construction of a road over valleys or mountains.
What is called a true level follows the circumference
of the earth; an apparent level regards the earth as a
plane surface, and is, in fact, a tangent to the earth.
In levelling through long distances, an allowance is
made for the curvature of the earth, for which purpose
accurate tables have been completed for all distances
within the range of an observation. Allowance is
also made for refraction, which varies from %th to 511th
of the angle subtended by the horizontal distance of
objects. In the ordinary state of the atmosphere,
the refraction is about T‘zth of the horizontal angle,
and the radius of the curvature of the ray 7 times
that of the earth. The effect of refraction may be
allowed for by computing the correction for. curva-
ture, and taking lfth for the quantity by which the
object is rendered higher by the refraction than it
ought to be. Tables have been prepared for making
the necessary corrections for refraction.
The staff or target used for determining the height
of the several objects above or below the level line, is
shown in Fig. 1306. It is usually a F
rod 1; inch square and 6% feet long;
it is made of mahogany, and inlaid on
its face with a white wood, to receive
the graduation marks and figures. It
is formed of two pieces dovetailed into
each other throughout their whole
length, so that one half of the rod
slides upon the other, so as, when
drawn out, to form a length of 12 feet,
and yet leave a foot of the two halves
united, to preserve the straight line of
the instrument. The divisions are
reckoned from the bottom of the staff.
The vane is a thin piece of mahogany,
10 inches long and 3 wide, with pro-
jections behind, which form a socket
for fitting the rod, and allowing it to
slide up and down. There is a flat ‘3
spring in the socket for making the
motion more precise. The centre of if‘
the vane has a hole, through which Hi may be read off the figure on the staff, F5} 13m},
and the edge of this hole being chamfered, the
horizontal wires of the telescope which cross it can be
distinctly perceived as they lie over the divisions of
the scale beneath. Fig. 1306 shows a portion of


L2
14.8
LEVELLING. ‘
the staff g e brought within the vertical wires 0 a of
1 a the telescope: ab
represents the hori-
zontal wire. When
the staff is placed
inavertieal position,
the vane is elevated
or depressed by the
person holding it,
according to certain
signals given by the
engineer at‘ the level-
ling instrument, un-
til the vane is made
to coincide exactly with the horizontal wire. When
the cross wire of the vane is raised so high as to
intersect 6 feet, there is a stop to prevent its being
pushed higher; when a greater height is required,
the vane is put to this height, and is raised by
sliding up the front portion of the staff, which
carries the vane with it. The rods are graduated in
different ways. Some have a double scale of divisions
running up the middle of the front; some are gradu-
ated into feet and inches divided into tenths; others
into feet divided into hundredths. The calculations
are more easy when the levels are taken in inches
and tenths, or in feet and hundredths.1
'. Gravatt’s scales, Fig. 1308, now in common
use, have no vanes; their graduations are marked in


0 grid
___.-a/
Fig. 1307.

F


= T r] feet, tenths,
Em and hun—
E ~~- dredths: they
I“ are made of
Inn-‘I '
: three pleces
. a‘ of mahogany,




with joints at
the ends for
uniting them
in one length of
l'l'lfeet or more.
Such staves
can be packed
up with the
stand of the
in s t rum e nt.
Mr. 'Sopwith
has added a
. spring catch
to the sliding
part ; but care
is required lest
when the face is turned from the last forward station
to become the next back, an error of %;th inch result
from placing it carelessly on the ground.
The most simple and usual method of levelling is as
follows z—Convenient stations A, B, &c. Fig. 1309,
having been selected on the line of operation, the






;muumumunmumumurmuu
Q,’

1 1m

.Fig. 1308.

(1) Fig. 1307 represents the appearance of the wires and stafi‘ as
seen through an invertingltelescope. The horizontal cross wire
coincides with the division '20 above 16 feet, the stafi‘ being read
downwards in consequence of its apparent=_inversion: the reading
therefore of such an observation to be entered in the field book
- would. be 1620 feet.

distances between them are determined either by‘
actual admeasurement, or by computations founded
on the data afforded by a previous survey of the
ground. The spirit level is then set up at or near
the middle of the interval between every two such
points in succession. When the telescope thus
placed, as at a, has been made horizontal, an assistant
-a
j
ha

Z,
, 4/////


Fig. 1309.
at each of the stations A and B, holding a station-
staff in a vertical position, moves the vane along
the staff upwards or downwards, according to the
directions of the observer at the telescope, till it
appears to coincide with the intersection of the two
wires of the telescope, which coincides with the
optical axis or line of collimation. '" The points thus
determined on the staves are represented by m and n,
which are evidently level points, or points equally
distant from the centre of the earth. Therefore, the
heights Am and Bn being read on the graduated
staves, the difference between them will give the
relative heights of the ground at a and B ; that point
of course being the highest at which the distance of
the vane from the ground is the least. A similar
process is repeated with respect to the points B and c,
the instrument being placed at b midway between
them, and the operation is to be continued to the
end of the line on which the profile is required. It
is usual to insert in a book the heights Bn, 0 g, &c.
in a column headed Fare sights, and the heights am,
B p, &c. in a column by the side of the former headed
Baa/c sigbls. The dilference between the sums of the
numbers in these two columns is equal to the height
of one extremity of the line above the other.
Suppose, for example, it were required to find the
difierence of level between the points A and c, Fig.
1310 : a staff is set up at a, the instrument at B, and
another stafi at c at the same distance from B that B
is from A. The readings of the two staves are then



Fig. 1310.
noted; the horizontal lines connecting the staves
with the instrument represent the visual ray or line
of sight. The instrument is then conveyed to n, and
the staff which stood at x is now removed to E, the
staff 0 retaining its former position, and from being
the forward staff at the last observation, it is now
the back staff; the readings of the two staves are
again noted, and the instrument removed to F, and
the staff ctothe point G; the staff at E retaining the
same position, now becomes in its turn the back staff,
and so ‘on to the end of the work, which may thus be
extended many miles. The difference of any of the
two readings will show the difference of level between
the places of the back and forward staff; and the
difference between the sum of the back sights and the.
LEVELLIN G—LEVIGATION—LEWIS.
14:9
sums of the forward sights will give the difference of
level between the extreme points : thus,—
Back Sights. Fore Sights.

ft. dec. ft. dec.
Aando . . . 10 46 11 20
o ,, n . . . 11 33 8 00
r ,, e . . . '7 42 . 7 91
Sums . . 29 21 27 11
2'7 11
Difference of level 2 10, showing that the

point G is 2 feet and llo°oths higher than the point A.
In order to enable the engineer to determine the
depths of his excavations or the heights of his em-
bankments, the profile of the ground is laid down on
paper in portions of convenient length. A right line
is drawn to represent one parallel to the horizon, and
it passes through the highest or lowest point of the
natural ground: the heights or depressions of the
remarkable points, as A B, &c. with respect to such
line, are obtained by additions or subtractions from
the numbers in the field-book, and are by a proper
scale set out from that line, (ir others drawn perpen-
dicularly to it, at intervals equal to the horizontal
distances between the same points. On joining the
series of points thus obtained, the figure of the
required vertical section of the ground is obtained.
If it be merely required to ascertain the difference of
level between two places, it is not necessary to level
in a straight line between the two places; and, indeed,

the presence of woods and water may prevent such a '
method: a circuitous route is in such cases adopted.
The reader who desires further information on this
subject, is referred to the works which we have con-
sulted in preparing this and the previous article, viz.
Mr. Simms’s Treatises on Levelling, 2d edition, 184.3 ;
on Drawing Instruments, 1845; and on Mathematical
Instruments, 1836. Also the articles Levelling and
Spirit Level, in the Penny Cyclopaedia.
LEVER, see MECHANICS.
LEVIGATION is the process by which substances
are reduced to a state of minute division by rubbing
them between two hard surfaces when formed into a
paste with water. It is distinguished from TRITURA-
TION, in which the comminution is effected without
the aid of a liquid. The porphyry slab and muller
used in trituration is also used in levigation ; but in
Germany a shallow porcelain vessel is employed. In
the process of levigation an amount of pressure is
required beyond that which the weight of the pestle
would usually produce. This is effected by means of a
wooden spring, Fig. 1311, fixed to the ceiling, to the
free end of which is attabhed a square block of wood 5,
with a. conical hole in the centre, in which the pointed
end of the handle or shaft of the pestle works. The
pestle is represented standing in a levigating vessel,
and the shaft of the pestle admits of being lengthened
or shortened by means of the long rod, and the bind-
ing screws 38. The dotted lines 6' show the position
of the spring in its free state, before applying the
pressure, which is of course regulated by adjusting
the length of the rod by means of the screws.

Substances which have been finely divided by levi-
gation are in some cases formed into small conical
7R% s.
%%
fee

w‘
“i \\ \\\\\\
'2" w


masses while moist, for the convenience
of drying. For this purpose they are
placed in a small hollow metallic cone 0,
Fig. 1312, fixed in a circular wooden
frame j, which ‘is furnished with a sup-
port Z, and a handle it. The levigated
and still moist substance being put into
the cone with a knife, the mould is in-
verted over a chalk stone, or other
absorbing surface, and the leg Z slightly
tapped until the conical mass falls out.
The nodules thus prepared are after-
wards dried by exposure to a current
of air. In this way the conical nodules
of levigated chalk, bole, and other sub-
stances are prepared.‘ .


Fig. 13H.
LEWIS. A simple but ingenious apparatus used
Fig. 1312.
by masons in hoisting large blocks of stone. Its in—
vention is commonly ascribed to a French mechanic
employed on the works of Louis the Fourteenth: the
name given to the machine was therefore in compli-
ment to that monarch. It appears, however, from
an examination of ancient ruins that an apparatus
answering similar purposes was in use long before
the age of Louis le Grand. Whitby Abbey, origin-
ally founded in 658, and rebuilt as a church in the
reign of William Rufus, long formed one of the most
beautiful ruins of this country. In 1762, during a
violent storm, it fell to the‘ ground, yet so excellent
was the cement used in its construction that the
pillars and arches remained prostrate in nearly their
original forms. Some of these stones, especially the
key-stones of the arches, the largest of which weigh
nearly a ton and a half each, present a cavity in the
crown, similar to those out into large blocks of stone,
for the purpose of raising them by the lewis.
The modern form of the lewis is shown in Fig.
1313, in which a and b are two pieces of iron in
the form of
verted wedges. (,7 .I
These pieces are ., . inserted into a /’// . " . , I k‘
quadrangular *3‘
hole made llltllfi Fig, 1313,
stone: the two opposite and shortest sides of the


6
(I) See Mohr 8: Redwood’s Practical Pharmacy, London, 1849.
150
LEWIS~~LICHENS~~LIFE~BOAT ‘‘
hole are dove-tailed, as shown in the figure, which
represents a vertical section of the hole, lbeing the
plan of the hole at top, and 0 the plan of the hole at
bottom. The dimensions are 5 inches long at the
top and 6 inches at bottom: the width 1 inch and the
depth '7 inches. The width is sometimes 1% inch and
the depth 41 or 5 inches. The pieces a b being first
introduced into the hole, 0 is driven in and a bolt
I)’ b”, Fig. 1314, is passed through the holes: 9" is the
ring of the lewis on which the tackle is hooked; each
end of this is likewise perforated to receive the bolt,
which enters at b’ and forelocks at 6”.
Mr. Gibson, who first discovered tokens of the use
of the lewis in Whitby Abbey, remarks that the




Z 'ilh‘ut'u 5,, \ * \\\ \ \\~\ \\ \ \\ .s
§\ \\\\ xx“
Fig. 131%. Fig. 1315.
machine used at that period must have been of a
somewhat different form and considerably less power-
ful than that now employed; yet he estimates its
strength to have been equal to the raising of a block
of four tons, which is larger than any stones found
in ancient buildings. Fig. 1315 represents the sup-
posed form of the lewis used at the erection of
Whitby Abbey. In forming the cavity, the point a
was left apparently as a guide to point the two
principal members cl e of the machine to their destined
places, where they were secured by a third part 6
perforated at the head to receive, in conjunction with
0 cl e j; the forelock bolt.
LICHENS. Cellular flowerless plants, spreading
over rocks, trees, or even dry bare earth, and having
in most instances a dry crustaceous nature, or a fleshy
substance variously coloured. In some cases lichens
appear as grey or yellow stains, adding much to the
picturesque effect of old buildings; in others they
hang in mossy luxuriance from the branches and
trunks of trees ; in others again they cover the earth
itself, springing up to a larger growth than their
fellows. These, in arctic regions, afford important
winter pasturage to rein-deer, the species commonly
called rez'ivrleee' more being a luxuriant growth of a
lichen (Ceizomg/ce magi/evince).
Lichens do not exist on decaying vegetable matter,
this ofiice being filled by the fungi. These are tran-
sient in their nature, whereas lichens are perennial,
and grow on the bark of living vegetables, as well as
on stones, &c. The finest species are met with near

the equator, but lichens are to be found in all parts
of the world, even to the limits of eternal snow.
Many of the species afford dyes, but the best known
are those which yield cudbear, and archil, well-known
dyes, described under ARCHIL. Some of the lichens
possess nutritive properties, depending upon the
presence of an amylaceous substance analogous to
gelatine. In the lichen called Iceland Moss (Cellar-la
islmzrlz'ea), Berzelius found 808 per cent. of pure
starch, or amylaceous fibre. Several of these gela-
tinous lichens, called Ti'z'pe (le roe/w, and forming vari-
ous species of Gg/roplaorcl, afford subsistence to the
Canadian hunters in cases of emergency.
LIFE-BOAT. In our article Boar the principle
of the life-boat is stated, and examples are given of
some approved forms. But the numerous cases of
shipwreck which have recently taken place, and
especially the lamentable accident which occurred to
a South Shields life-boat a few years ago, whereby
~ 20 pilots were drowned, have led to an act of munifi-
cence on the part of the Duke of Northumberland,
President of the National Shipwreck Institution,
which has already produced most important results,
and which calls for further notice. With a view to
stimulate invention, the President offered a reward
for the best model of a life-boat. This. offer was
responded to by boat-builders and‘ others from many
parts of this kingdom, as well as from France, Hol-
land, Germany, and America, so that 280 models and
plans were sent in. About fifty of the best of these
formed the Duke’s contribution to the Great Exhibi-
tion. With a generosity worthy of the sacred cause,
his Grace has likewise publicly expressed his inten-
tion of placing the best life-boats that can be built,
and every means for saving life from shipwreck, on
all the exposed points of the coast of Northumberland.
He has also caused to be prepared at his own expense
a Report, accompanied by plans and drawings of the
most approved forms of life-boat, 1,300 copies of
which have been gratuitously distributed, not only
through this kingdom, but in all the maritime nations
of Europe and the United States of America. From
this work we have been permitted to copy the illus-
trations which accompany this article.
No greater service could perhaps be rendered than
the spreading abroad in this manner, and as widely as
possible, the knowledge necessary for effective action.
A remarkable degree of supineness has hitherto pre-
vailed on this important subject, and of the life-boats
at present stationed on our shores, we regret to say,
one half are deemed unserviceable. A most interest-
ing Wree/e Chart for 1850, which appears in the Re-
port of the Northumberland Life-boat Committee,
shows the existing life-boat stations on the coasts of
Great Britain, and also marks the number of wrecks
which took place in that year. It appears that 681
British and foreign vessels were wrecked on the
coasts and within the seas of the British isles, during
the ‘year, and that of these 367 were total wrecks,
sunk by leaks, or collisions, or abandoned, and 3041
were stranded and damaged so as to make it neces-
sary to. discharge the cargo. About 780 lives were
.LIFEBOAT.
151
lost‘. ' These numbers, large 'as they appear, are not
unusual, but fairly represent the nature of our annual
loss. A single gale of wind often strews our coasts
with wrecks, and causes wide-spread sorrow and be-
reavement. In two days, viz. the 25th‘ and 26th of
September, 1851, 117 vessels were wrecked within
our seas, during the gale which then prevailed; and
during the month of January of the present year,
120 vessels have shared the same fate. These num-
bers, fearful as they are, may perhaps fall considerably
below the real amount, for no complete and accurate
record of shipwrecks is kept. To meet this appalling
amount of damage we have on the coast of England
eighty life-boats, in Scotland eight, and in Ireland
eight, making ninety-six in all, only one half of which
are really effective.
These facts sufficiently prove the necessity for more
active exertion in endeavouring to save life on our
shores, and the value of the steps‘ taken by the Duke
of Northumberland. Baron Dupin, in his capacity
as chairman of the jury, under which the life-boat
models were found, declared them to be among the
most valuable productions in the Great Exhibition;
and remarked that these, taken in connexion with the
facts stated, furnished “a splendid example of libe-
rality in the cause of humanity and practical science,
never surpassed, if ever equalled.” The Northumber-
land Prize—model—for which the sum of one hundred
guineas was given to Mr. James Beeching of Great Yar-
mouth, represents a boat that will pull and sail well in
all weathers, and whose excellency for the purposes re-
quired has been proved at Ramsga'te, where a boat built
after the model is now stationed, and acts admirably.
This boat has a moderately small internal capacity
under the level of the thwarts for holding water, and
ample means for freeing herself readily of any water
that might be shipped; she is ballasted by means of
water admitted into a well or tank at the bottom
after she is afloat, and by means of that ballast, and
raised air-cases at the extremities, she would right
herself in the event of being upset. At an able Lec—
ture on Naval Architecture, delivered by Captain
Washington, R.N., before the Society of Arts, March;
3, 1852, being one of the series in illustration of the
benefits of the Great Exhibition, the subject of life-
boats was fully entered on, and a model of the above
life-boat was placed on the table, and described.
Captain Washington also favourably noticed many
other life-boats, of which models were sent to the
Great Exhibition; and expressed satisfaction at the
number sent by men who are earning their daily
bread as working shipwrights or boat-builders in the
various private and public dockyards of the kingdom.
He also enumerated the essential points as to form,
dimensions, internal fittings, &c. necessary to be con-
sidered in the construction of a life-boat. Of this
part of his subject, as contained in the copy of his
lecture distributed to the members of the Society of
Arts, we give the following abridged account :—
FoRnL—In form, the life-boat should resemble the
whale-boat, that is, both ends alike, but with more
breadth of beam; fine lines to enable the boat to pull

well, but sufiicient fulness forward to give buoyancy
for launching through a surf; good sheer of gunwale,
say an inch for each foot of length, but rounded off
towards the extremes; a long flat floor; sides
straight in the fore-and~aft direction; the gunwale
strake in the midships to tumble home slightly to
protect the thole-pins, and the bow strake to flare
out slightly to throw the sea off ; as much camber or
curvature. of keel as can be combined with steady
steering, and safe launching from a beach, in order
that the boat may be turned quickly to meet a heavy
roller when about to break on her broadside.
DIMENSIONS.-—-AS to Zengfli, life—boats may be gene-
rally classed as from 20 to 25 feet, from 25 to 30, or
from 30 to 36, the last being the maximum. The
smaller size is convenient in parts of the coast where
it is difficult to find a crew; as being more easy of
transport on shore, and more readily manned and
launched. Such a boat, with six men, will generally
bring on shore the whole of the crew of a stranded
vessel. Two boats, one of only 18 feet length, the
other 24 feet, built by Plenty, of Newbury, have been
the means of saving 120 lives within the last few
years. Where a sufficient crew can be found, a boat
of 30 feet length, to pull ten oars double-banked, is
probably the best adapted for a life-boat. Such are
the boats at Liverpool, Dundee, and other large
ports. One of these is said to have brought ashore
at Liverpool on a special occasion, 60 persons. The
maximum boat of 36 feet is used at Yarmouth, Lowea
stoft, Deal, &c. where it is the invariable custom to
go off under sail, and where there is never a difficulty
in finding beachmen to launch or man the boats, of
whatever size. Some boats of extraordinary size,
which may be considered exceptions to the general
rule, are also in use at the above places. These are
from {L0 to 415 feet long, admirably manned and
handled, and have been the means of saving about
300 lives within the last 30 years. With respect to
breadth of beam, in a rapid tideway, as the Tay, the
Humber, the Bristol Channel, &c. a boat, somewhat
of the galley form, but with ends like a whale-boat,
would be more suitable than a wider boat. In these
exceptional cases the breadth of beam might be one-
fourth the length; but for a life-boat, where the
requirements are roominess for passengers, width to.
pull double-banked, stability to resist people moving
about, and occasionally pressing down on one side in
rescuing a man from the water, it should never be less
than one-fourth. As to depth, a boat that has to be
launched through the surf on a beach should not be
too shallow in the waist. As a general rule the free-
board or height of gunwale, from the surface of the
water, with crew and gear on board, should not be
less than from 22 to ea inches. The weight suitable
to a life-boat does not appear to have been much
attended to, but Captain wWashington gives, as a fair
general rule, 1 cwt. or 1% cwt. for each foot of length.
The weight of gear would vary from 5 cwt. to 15 cwt.
according as it comprises oars, masts, sails, anchor,
cable, warps, &c. Whatever the length of the boat,
the space between the thwarts should not be less than
152
LIFE-BOAT.
from ‘28 to 30 inches, or the loom of ~one man’s ‘oar
is liable to strike the back of the man abaft him. The
cars should be short to pull double-banked, and of
fir- They should pull with iron thole-pins, having
ropelgrummets‘ secured to them, and the pins should
be so :-plaeed' that the boat may be pulled either way
by the man merely turning round on the thwarts.
M‘nTBBmLsQ—About one-tenth of the models sent
to the Exhibition were of iron,‘ but Captain Washing-
ton does not advocate the adoption of metal for life-
boats, and supposing them to be introduced he thinks
copper preferable to iron. ' Wood has been the
material hitherto employed, and of this, well-seasoned‘
Scotcli larch is the best, its specific gravity being
little “more than double that of cork. _ Neither Polish
nor Italian larch should be trusted to. Gutta-percha,
caoutehouc, and other materials have been proposed,
but their merits have not been sufficiently tested.
Combinations of these with cork, or with layers of
thin Wood, seem well adapted for air-cases.
E'xrrlaa Buorxncv. —— This is the characteristic
feature of a life-boat, therefore its nature, amount,
and distribution require close attention. If sufficient
buoyancy can be attained by cork, it is far preferable
to air-“eases, as not being liable to accident. A por-
tion of cork may be used under the flat or floor of the
boat,,so as to reduce the internal capacity, and enable
the boat to free herself of water. Cork varies in weight
and in: price. The common sort used by fishermen
as floats only weighs about 12 lbs. per cubic foot, and
costs about 12s. per cwt. A heavier sort weighs
15 lbss. per cubic foot. These might be advanta-
geouslyf disposed in the bottom of the boat, covered
with: gutta-percha, or a light casing to keep the water
out off it, and the boat might then bid defiance of
accidents, as thus armed,—even if bilged against a
rock,.sl-1'e would float. With respect to air-cases, those
WhlClllhaVG been built into the heat can scarcely be
depended upon for a year. On inquiry there is
reason ito believe that there does not exist a complete
air oruWater-tight case (undetached) in any life-boat
that has been six months in use around the coasts
of Great Britain. Detached air-cases may be better,
but all require extreme caution. Metal air-cases are
supposed to offer security, but in a life-boat laid open
at Woolvvich several holes were found half an inch in
diameter in the copper tubes previously supposed to
be ai'retight. Copper like other metals is all the
more liable to corrode when placed in conjunction
with sea—water. Teasdel, an experienced life-boat
buildervat Great Yarmouth, makes his detached air~
cases. of thin boards of willow wood covered with
painted l canvass. The cubical contents of the air-
cases in ~a great part of the models sent to the
Exhibition measured from 200 to 300 feet, equivalent
to the; support of from six to nine tons of dead
weightL. This amount is unnecessary, to balance the
extra weight likely to be put into a life-boat. In a
30 feet boat, provided with ample delivering valves,
100 cubic feet, or the equivalent of three tons, is
sufiici'ent extra buoyancy for all general purposes.
The distribution of this extra buoyancy requires

great care: except under special circumstances it
should be placed high up in the boat, so as not to '
affect her stability. In order to reduce the internal
capacity of the boat, that she may rise under the
weight of a heavy sea that may fall on board, and to
enable the delivering valves to act freely, a certain
amount of space should be occupied under the flat or
floor of the boat, so as to exclude the water; and
the question is, so to fill this space with a material of
less specific gravity than water, yet sufliciently heavy
to ensure the boat’s stability when the flat or flooring
is laid at from 10 to 12 inches above the keelson, or
about the water-line of intended immersion; thus
acting generally as ballast, but on emergency as
extra buoyancy. From the various plans adopted
this would seem the most difficult problem to solve
in the whole arrangements of a lifeboat. In some
cases a tight deck is placed fore and aft at from 16
to 18 inches, and even 24 inches above the keelson,
with only air beneath; the result. is, that the weights
in‘ the boat raise her centre of gravity, and there is
a risk of her upsetting when a sea is shipped. In
other cases, to avoid this danger, an iron keel is
added, or a well or tank is inserted amidships for
water ballast, which, as long as it remains in place,
restores the equilibrium. Water ballast has the
advantage of being taken in only when the boat is
afloat, and thus leaving her light for transport on
shore; but the use of cork under the deck, as above
described, is considered preferable by Captain Wash-
ington. The next point in the distribution of extra
buoyancy, is the placing of a requisite amount of
air-vessels in the head and stern sheets of the boat
from the floor up to the gunwale height, in order to
give self-righting power, always taking care to leave
access to within three and a half or four feet of the
stem and stern post, to enable a man to stand there
and ‘receive people from the wreck, as it commonly
occurs that a boat cannot go alongside a stranded
vessel, but has to receive the rescued men either over
the head or stern of the boat. Air-cases should also
be placed along the sides of the boat fore and aft,
chiefly to diminish the internal capacity. They
should be detached and have valves inserted in them,
by which they can be aired and preserved better.
Well’s disc valve is recommended. The more the
internal capacity can be reduced consistently with
leaving space for the rescued crew the better the
life—boat. If possible, the'capacity for holding water
up to the level of the thwarts of a boat 30 feet long
should not exceed three tons. It may be diminished
by side air-cases from the thwarts to the floor, or by
air-cases under the thwarts. _
Means or Fitnnnve run Boar or Warns—‘Every
life-boat should be provided with the means of free-
ing herself of water as rapidly as possible. Yet in
some of the .models no provision is made beyond a
bucket for baling. The provision required consists
of efficient tubes and scuppers, closed by self-acting
valves. A boat can free herself most rapidly by
tubes through the bottom, but as these are liable to
be choked inthe possible case of a boat grounding, it
LIFE-BOAT. 153
is‘ better also to have scuppers in the sides. The
' area of the tubes should not be less than one square
inch for each cubic foot of capacity; more would be
better.
Pnovrsion non SnLr-nienrrne.—Tlie property of
self-righting, when recently proposed as one of the
requisites of algood life-boat, was almost treated with
contempt by some of our best boat-builders, yet it
was this property which was publicly acknowledged
and exhibited at Leith in 1800 by Mr. Bremner, whose
boat is figured at page 148, vol. i., under our article
Boar. Since his time the provision for self—righting
has been neglected, and the consequence has been
that instances have occurred of life-boats when upset
remaining bottom upward, to the destruction of the
poor creatures beneath. This proves the necessity
of grappling with the difficulty, if such it be, and of
overcoming it. “ Most life~boats have good sheer of
gunwale, and consequently raised extremities, in
which air-cases should be placed, in order that when
the boat is bottom upwards, their buoyancy may co-
operate effectually with the weights in the bottom of
the boat (now raised, it may be, considerably out of
the water) to restore her to her originally upright
position. The higher the centre of gravity of a
vessel or boat is above the centre of buoyancy, ccez‘erz's
pm'z'bus, the less is her stability; and by the separa-
tion of these two centres, a condition of instability
will ensue, the effect of which will be, that with the
slightest motion the boat will reverse her position, or
right herself. To determine the necessary extent of
separation of those centres in each case involves
careful calculation. The best mode of applying this
principle will readily occur to most boat—builders.
The objections to the raised air-cases at each end are
the wind they hold in pulling off a lee-shore, and the
obstacle to approaching the stem and stern of the boat ;
the latter may be modified, the former must be
tolerated for the greater benefit in another respect
that arises from their adoption. If air-cases be used
in the extremes, a layer of cork on
the top will afford great protection to
them, and better footing for the crew
when necessity requires them to stand
or jump on them.”
BALLAST. —- The advantages of
water-ballast have already been '
stated. It is necessarily used in
connexion with so-called water-tight cases, and there-
fore requires very good workmanship in the bulkheads
or partitions of the well, in order ‘r. Mr
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straining when at sea, or by shrinking , f“ b
when the boat stands ashore, whichj \
she sometimes does for a year to-i \bh
gether. A doubt may arise, too, E D
whether a boat does not require her
ballast as much, or more, at the time
‘of launching than at any other time; lightness has
its advantages, but in launching through a surf, a
boat requires a certain weight, so as not to be readily
thrown aside by a breaking sea. After all, the ballast



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Fig. 1317.
supplied by cork seems‘ the best adapted to meet‘ the
varied contingencies to which a life-boat is subject.
Also a moderate sized cork fender, about four inches
in diameter, should be carried round the sides and
both ends of the boat, at ‘about six inches under the
gunwale. Holes in the bilge pieces, to enable a man
to lay hold of them, should the boat be upset ; timber
heads to make warps fast to at each bow and quarter;
long sweep cars for steering at each end; a stout
roller in the stem and stern-post to receive the cable;
spare oars, one for each two that the boat pulls; life-
belts, life-buoys, and life-lines; hand-rockets, heaving-
lines, and such minor fittings, are indispensable in
every life-boat.
TRAN sronrrne CARRIAGE—Th8 carriage for trans-
porting a life-boat along shore, or when the tide is
out, for carrying it down to the water, and launching
it without risk, should combine lightness with strength
to carry at least 40 cwt. in case of need. The boat
should be supported as near the ground as may be,
so as not to strike the bottom in going over a rocky
beach. The wheels should be of large diameter, with
broad tires to prevent their sinking in the sand. Of
the models sent to the Exhibition, not one exactly
fulfilled the conditions which seem essential. But a
carriage is now in the course of construction at the
Royal Arsenal at Woolwich, which it is hoped will
prove to be well adapted to its purpose.
The essentials of a life-boat thus gathered from
the statements of an experienced naval officer, will
prepare the reader to understand the merits of two
life-boats, of which figures are given—the one being
the prize-boat which gained the premium offered
by the Duke of Northumberland, and which was
decidedly the best of the competing models with
referenceto the points already laid down ; the second
being a more recent boat, in which, after a careful
study, the good points of all the competing boats
representing the essential features of a good life-boat,
have been combined and exemplified.








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Fig. 1316. PLAN 01? THE NORTHUMBERLABD PRIZE BOAT.
‘Figs. 1316 and 1317 are the plan and sheer plan
of the Northumberland Prize Boat. The letters mark





y a
nonrnmrnnnnaxn PRIZE BOAT.——Sh887' Plan.
the fore-part of the boat, the figures the aft. The
dark parts of Fig. 1316 represent air, the light part,‘
water. The dark band in Fig. 1317 represents 009%,
the, other tints air and water. The body of this
15%
LIFEQBOAT.
boat is of the form usually given to ‘a whale-boat—e
a slightly rounded floor, sides round in the fore and“.
aft direction, upright stem and stern post, clench-
built, of Wainscot oak, and iron-fastened. Length
extreme 36 ft., of keel 31 ft., breadth of beam. 9% ft.,
depth 3% ft., sheer of gunwale' 36 in., rake of ‘stem
andstern-post 5 in., straight keel :8 in. deep. The
boat has 7- thwarts 27 apart, '7 in.‘ below the
gunwale, and 18 in. above the floor; ’pulls'12 oars,
double-banked, with pins and grumm‘ets. A cork
fender, 6 in. ‘wide by 8- >in.-deep, rrmsround outside at
7 below the gunwale.. Extra buoyancy-is given
by air-cases 20 in. high in the bottom of the boat,
under the flat; round part of the sides, 24b in. wide
by 18' in. deep, up to the level of the thwarts, leaving
10 ft.- free amidships ; and in the head and stern
sheets; for a length of 8% ft., to the height of the
g-unw-ale; the whole divided into compartments and
built into the boat, also by the cork fender-s. Effec-
tive extra buoyancy 300 cubic ft., equal to 8% tons.
For ballast a water-tank, divided into compartments,
placed in the bottom amidships, 14: ft. long by 5 ft.
wide, and 15 in. high, containing 77 cubic ft., equal
to 2% tons when full, and an iron heel of 10 cwt.
Internal capacity of boat under the level of the thwarts
1'7 6 cubic ft., equal to 5 tons. Means of freeing the
boat of water, tubes through the bottom, 8 of 6 in. dia-
meter, and a of A in. diameter—total area, 276 square
in., which is to-the capacity in the proportion of 27 6 to
17 6, or as 1 to 641. Provision for righting the boat
if upset, 2%; tons of water-ballast, an iron heel, and
raised air-cases in the head and stern sheets. Rig,
lug foresail and mizen; to be steered by a ‘rudder;
no timber heads for securing a‘warp to. Draft of
water with 30 persons on board, 26 in. Weight of
boat, 50 cwt., of gear, 17 cwt.—total, 67 cwt. Would
carry '70 ‘persons; cost, with gear, 250l.
Figs. 1318 and 1319 represent a boat which is
supposed to combine the good points of all‘the others.
It is the work of Mr. James Peake, Assistant Master


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Fig. 1318. PLAN OF rEA'Kn’s LIFE-BOAT.



keel 2a a, breadth of beam aa- a, depth ~31; a., rake
of stem and stern—post 6—12— in. in a foot; straight keel, ~
4ein. deep, and bilge-pieces with openings in them to
lay hold of, on each side on the bottom. The boat has
5 thwarts,v '7 in. wide, 28 in. apart, 7 in. below the gun-
wale, and 15 in. above the yfloors,-pulls 10 cars, double-
banked, with pins andgrummets. A fender of cork,
‘ 4: in. wide by 2% deep, extends fore and aft at a in.
below the gunwale. Extra buoyancy is obtained by
cork (shown by the light tint in Fig. 1319), placed the
whole length ofrthe boat," under the flooring, to a height
of 12 in. above the keelson, and by light cork or de-
tached air-cases in the head and. stern sheets up to gun-
wale height. Effective extra buoyancy 105 cubic ft.
equal to 3 tons. A light water-tight deck will be placed
on the cork to protect it, and above that a light grating.
For ballast, the weight of the cork in the bottom, and
an iron keel of 5 cwt. Internal capacity for holding
water up to the level of the thwarts, 140 cubic feet,
equivalent to 41 tons. The means of freeing the boat
of water are by 8 tubes of 6 in. diameter through the
bottom, and 6 scuppers through the sides at the
height of the flooring, giving a total delivering area
of 300 square inches, which is to capacity as l to 5.
The provision made for righting the boat consists in
the sheer given to the gunwales, raised air-vessels or
cork in the head and stern sheets, and the ballast
arising from the weight of cork in the bottom, and
the small iron keel. A passage 18 in. wide, up to
within 2 ft. of the stem and stern is left between the
raised air-cases in the extremes, and the top of the
cases is protected by a layer of cork. Rig, fore and
mizen lug sail. To be steered by a sweep oar at
either end. Timber heads for warps are placed at
each bow and quarter, and a roller for the cable in
the stem and stern—post head. A locker under the
flooring amidships for the anchor and cable to be
secured down to the keelson, and covered with a
water-tight scuttle. A life-line fore and aft at a foot
below the gunwale, and short knotted life-lines to be
hung over the side at each thwart.
Draft of water with 30 men on board,
16 in. Weight of boat and fittings,
38 cwt. Would carry 60 persons.
Actual cost, as built in one of H. M’s.
dockyards—materials, 4.0L; ,labour,
415l.: total, 85l.
It is anticipated that this boat,
from her form, will ‘pull fast in all
Shipwright in Her Maj esty’s Dockyard, Woolwich. weathers, and be fully abl'e'to contend against a head
The form of this boat is that usually given to awhale- sea. She would Sail W611, and from her flat and 1011?;
boat,-~having._a long flat floor amidships, sides straight floor‘ I; 5l2¥218hl3 Sides, would have great- stability,


‘and ; prove a good sea-boat. Aboat
H {of this. form could not be readily
" f jupiset,“ but should this occur, the
sheer of gunwale, raised air-cases in
the extremities, weight of cork in

B
Fig; 13-19.
in, fore-‘andjaft I direction, raking stem and stern-post,
"twqthieknesses of rock elm‘, and
copper-fastened; ’Leng'th extreme, 30 ft., length of
a
PEAKE'S LIFE-BOAT.—Sll€87‘ Plan.
the ‘bottom, and iron keel, would
~ - ‘cause her to right herself. The heat
would ‘readily‘fr'ee herself of water, and if the ample
delivering-‘tubes ‘became choked, there are suflicient
scuppers at the ‘sides. The builder only offers this
LIFE-BOAT—LIGI'IT.
155
as a selection from the‘best ‘points. of other boats,
but it appears better adapted for the‘ purpose than
any other. One of these boats is to be placed at
Cullercoats, on the coast of Northumberland, two
miles north'of the ‘entrance of the Tyne—a station
well adapted for ‘testing its capabilities.
We cannot leave this subject without expressing
both ‘regret and shame, that the cause of seamen
excites so little interest among the ‘inhabitants of
our sea-girt isle. It ‘is reckoned that a thousand
British lives are lost annually from shipwreck, and
the greater part on our own shores; yet hitherto
only a few feeble efforts have been made to lend a
helping hand to those whose business is on the great
waters, and to provide them with the means of
rescue in their distress. Our markets and our tables
are richly supplied with fish, and it would appear a
hardship if it were not so; but how little thought is
bestowed upon the men whose perilous calling fur-
nishes these luxuries. How coolly are shipwrecks
and their results spoken of, as a matter of course, in
stormy weather! Surely this apathy has greatly
arisen from ignorance that anything could be done to
lessen the evil. Surely it is not generally known
that there is such a Society as the National Ship-
wreck Institution,1 with a President at its head,
whose unexampled generosity puts us all to shame.
That Society, undeterred by its very small means, is
endeavouring to increase the number of life-boats,
and other means of help on every coast, and to
stimulate exertion by rewards honorary and pecuniary.
It also spreads abroad, as far as it can, the knowledge
of what is necessary to be done in cases of emer-
gency, calling attention to the neglected state of
some existing life-boats, and putting on record the
brave deeds of those who risk their own lives to
save their fellow-creatures. Such a Society ought to
be supported as a matter of duty by every English-
man who has the means. How know we, but that,
for want of the life-boat which this Society desires to
place on every exposed part of our island, our own
lives or those of our friends may be sacrificed? Like
Southey’s “ Sir Ralph the Rover,” who mourned too
late the destruction of the Inchcape bell, which
warned him from the fatal rock, we may yet have to
mourn the neglect which deprived us of the means' of
rescue from shipwreck. A recent publication of the
National Shipwreck Institution, issued monthly,
under the title of the “Life-Boat,” (price three-half-
pence,) gives a list of shipwrecks every month, with
many interesting particulars connected with the
subject.
LIGHT. It was'formerly supposed that light was
an emanation of material particles from luminous
bodies; but in our own day, philosophers incline to
the opinion that it is produced by the undulations in,
or vibrations of, an elastic ether. It is not necessary
to refer to either hypothesis in explaining a few of the

(1) The oflice of the Royal National Shipwreck Institution, is
at 20, John Street, Adelphi. President—The Duke of Northum-
berland. Secretary.—-Mr. Richard Lewis, to whom letters should
be addressed. ' l

elementary effects to' which ‘a ‘ray of light is ‘subject
under various circumstances. It is evident. that some
substance or action, which we call lip/ii, travels from
every visible point to the eye in straight lines, ra-.
diating in all possible directions from every visible
point of matter, whether emitting light from its own
resources, or dispensing what it receives from some
foreign source. By calculations based upon the
eclipses of the four satellites or moons which revolve
round the planet Jupiter, astronomers have ascer-
tained that light travels at the rate of 192,000 miles
in a second. By another phenomenon, called the
adermi‘ion of light, this fact has been confirmed,
together with the additional one, that light, from
various celestial sources, travels with the same speed.
This aberration is common to all the heavenly bodies,
causing them all to appear a little out ‘of their true
place, and it forms one of those corrections which
must be applied to every celestial observation. It
arises from an application of the principle advocated
by the sportsman, of “shooting before the hare.” As
the observer is moving along with the earth, at the
same time that the light is travelling to him, it fol-
lows that, if he point his telescope exactly towards
any celestial object, he will not see it, because the
light which enters the telescope will, before it can
reach his eye, be struck by the side of the tube; un-
less, indeed, he be travelling exactly iowards or flow
the object, in which case there is no aberration. In
other cases, the telescope must evidently be pointed
a littleto one side of the object in order to see it, so
that almost every star is seen out of its place. Now,
the amount of vthis displacement being ascertained, is
found in all cases, whatever he the object seen, to be
exactly such as may be calculated from the known
velocity and direction of the earth’s motion, taking
the velocity of light always at the same rate, viz.
192,000 miles a. second. The earth’s motion being
very slow compared with this (barely a 10,000th so
fast), the amount of the aberration is very small,
never exceeding 205", or about half the apparent
diameter of Jupiter. '
The motion of light, under ordinary circumstances,
in straight‘ Zines only, is probably 5 the first physical
fact that we learn, and that on which we found every
inference‘ depending on the evidence of vision. It is
to some‘ exception to this law that every variety of
ocular illusion or deception is referable; for when the
rays coming from any object suffer any bending before
arriving at'the eye, the object is seen out of its true
direction, viz. in that direction which is last assumed
by the rays immediately before entering the eye.
Light not only proceeds ordinarily in straight lines,
but such lines or rays emanate from every point of
'a _visible object, and proceed‘ every direction. Any
number of rays of light can cross each other in the
same point of space without jostling. If a small hole
be made' from ‘one room into another through a thin
screen, any number of candles in one room will shine
through this hole, and illuminate as many spots in the
other room as there are candles in this, all their rays
crossing in the same hole, without hindrance or dimi-
156
LIGHT.
nution of intensity, just as sounds of different charac-
ter proceed through the air, and speak to the ear, each
in its own peculiar language, without materially inter-
fering with each other.
Owing to the rectilinear motion of light, the pencil,
as it is called, which emanates from any point dimi-
nishes according to the law of inverse squares [See
HEAT, Fig. 1135], and the apparent superficial size or
area of any object diminishes as its distance from us
increases, by the same law. Hence, as its apparent
size and the whole quantity of light received from it
are always proportional, its brzlq/ttaess remains the
same at all distances, and the sun appears to be no
brighter from Mercury than from the earth. This,
however, is only true in free space, and not in air,
because a portion of the light is absorbed in passing
through air, as explained in the case of heat, page 11,
causing the intensity to diminish rather faster than
the inverse square of the distance.
The investigation of these effects, and all others
deducible from the law of straight-lined motion alone,
constitutes the first branch of optical science, called
Pnnsrncrivn.
The application of this science, when no account is
taken of the absorptive power of the medium through
which we see, constitutes Ltizeal Perspective ; when
this consideration is added, it becomes Aerial Per-
speetz've.
The second science of light, called Oa'rorrnrcs,
investigates whatever is deducible from the law of
rejz'ea'z'oa, already explained in the case of heat. See
Fig. 1136.
As when a moving body strikes another at rest,
the mechanical force is divided and shared between
them 3 so when the action of light, propagated through
any medium, arrives at the surface of a new medium
either denser or rarer, more or less transparent than
the former, its force is divided, a portion entering the
new medium, and a portion rebounding into the old.
This latter portion belongs to Catoptrics. Its quan-
tity rarely exceeds lzalf the original light, except in
one case, to be noticed presently, where it includes
the zolzole effect. When the portion reflected from
any surface, or point of a surface, to the eye is con-
siderable, such surface or point appears w/a'te ; when
very little, it appears dark-coloured ,' and blaele when
the portion is inappreciable. Hence it is evident that
the same surface which appears to be white to an eye
in one position may appear to be black from another
point of view, as frequently happens with a mirror,
or some particular point thereof, or of any other
bright or reflecting surface. But surfaces which are
distinguished as reflective do not really reflect more
‘light than those which are termed clall or non-
reflective, provided the depth of colour be the same
in all. Burnished silver reflects no more light than
frosted silver, nor does the melted surface of sealing-
wax than the broken surface of a stick of that sub-
stance. N or do these dissimilar bodies reflect
according to different laws or by different kinds of
reflection; although such varieties of reflection as the
following have been distinguished ; —First. The

specala, or mirror-like reflection, according to the law
of equal angles, already explained in the case of heat,
Fig. 1136, by which each ray that arrives in one
definite direction is reflected only in one direction.
Second. The rarlz'atz'rzg or dull reflection, according to
a different law, by which each ray is scattered equally
in all directions. But in this case it may be proved
that a dull and a polished surface alike observe—the
law of equal angles: their diflerent effects may be
thus explained :—a dull surface, however smooth to
the touch, appears under the microscope to be so
covered with roughnesses on a small scale, that the
smallest visible portion of it contains not only surfaces
turned in all possible directions, but equally in all
possible directions. When these are large enough to
be visible, the surface is glittering, as in refined
sugar, fragments of marble, cast-iron, &c.; but all
these substances appear to be dall when viewed be-
yond a certain distance, just as all dull surfaces would
be glittering if we could place the eye near enough.
Each minute surface reflects each ray that falls upon
it according to the law of equal angles; but as sur-
faces lying in all directions exist in each visible point,
light is scattered in all directions from each such
point, even though it arrived there in only one direc-
tion. A reflective surface, as it is called, although
not free from roughness, contains in each visible
point a greater or less preponderance of surfaces
having one fixed direction. But in this, no less than
in a dull surface, each point radiates light in all direc-
tions, but only because, under ordinary circumstances,
it receives light in all directions. Confining our
attention to that which comes in one direction, and
which is often to be distinguished from all the rest
by some peculiarity either of intensity or of quality,
this is reflected only or chiefly in one direction 5 not
equally in all, as it would be by a dull surface.
All the appearances of opaque bodies, apart from
colour, and all the images of other bodies appearing
either behind or before mirrors or reflective surfaces,
whether such images be true or distorted representa-
tions, erect or inverted, magnified or diminished, may
all be accounted for by the law of equal angles, as
those of perspective are from that of straight-lined
motion.
Only a portion of the light which meets any surface
is reflected, the remainder being absorbed or trans-
mitted: when it is absorbed, the substance is said to
be opaque; but when we can trace it further, the
substance is called transparent. Opacity and trans-
parerzey are not opposite properties, but only very
different degrees of the same property. As radiant
heat of a given intensity can penetrate much further
through some media than through others before it is
entirely absorbed, or stifled, or expended in warming
them; so with light. Solar rays, for example, can
penetrate through some hundreds of miles of air, but
not through the thousandth of an inch of lamp-black
or of metal; for however much these two bodies may
difl'er in the proportions of light which they reflect,
and consequently in that which they allow to enter,
they both agree in stifling the latter before it has
LIGHT;
157
penetrated to any sensible depth within their surface.
Most other solids and liquids, however, can be re-
duced to such a degree of tenuity as not to absorb all
the light which enters them, but to allow some of it
to emerge on the other side; and as no medium,- not
even air, is perfectly transparent (for if it were there
could be no such thing as aerial perspective), so also
it may be supposed that‘no substance can be perfectly
opaque; of", in other words, that no absorption or
extinction of light can take place at a mathematical
surface; for even the densest metals, platinum and
gold, can be reduced to leaves sufficiently thin to
transmit a small portion of light. Perhaps no other
property is possessed in such various degrees by dif-
ferent substances as their power of absorbing light;
light loses less of its intensity in passing through
50,000 miles of matter of Encke’s comet than in
passing through a few yards of light fog, an inch of
glass, or a 300,000th of an inch of gold.
When light passes from one medium into another
(unless its direction he perpendicular to the surface
dividing them), that direction undergoes a sudden
change, which is called reflection. The investigation
of this property belongs to the third branch of optics,
called DIOPTRICS. The new direction assumed by the
ray is regulated by the following laws. Let AA, Fig.
1320, represent the surface of calm water, which is
necessarily polished, as that of all fluids must be, by
the operation of the molecular forces. No light will
pass through this surface unrefracted, unless it either
descend or ascend perpendicularly, as from r to r’, or
r’ to r. Any ray which falls obliquely, as B 0, will
he suddenly bent into the direction GB” ; and if it
arrive more obliquely, as D o, it will be more bent,
taking the direction 01)”. It will be seen that in
both cases the tendency of refraction is to render the
ray more nearly perpendicular to the surface than
before. But any ray which proceeds from the water
into the air undergoes a contrary effect, being ren-
dered less perpendicular to the surface. Thus, a ray
ascending in the direction is" 0 will, on emerging, take
the direction on; and one which, in the water, tra-
velled along 1)" 0, will, in the air, be bent into on ;
the bending in this case, no less than the former,
being greater the more oblique the ray may be to the
surface. Moreover, it is a law in refraction no less
than in reflection, that by whatever path a ray reaches
one point from another, by the very same path will a
ray travel from the second point to the first. An eye
at n", then, will see the object i), not in the direction
1)" D, but in the direction 1)" 0, higher than its true
place; and an eye at D will see the object 1)" in the
direction I) 0, also higher than its true place, of which
any one may convince himself with a basin of water.
An opaque body placed at C will hide n and n" from
each other, though not in a straight line between
them; and if it were in the straight line, it would not
hide them, for they see each round a corner at c.
The first part of the law of refraction is similar to
that of reflection, viz. that the angles of incidence
and refraction (zie. the angles which the incident and
reflected ray each make with the perpendicular or

‘normal of the surface, or in this case the angles r o n
and r’ o 1)") are both in the same plane. Any ray
meeting the surface of a new medium is split into two
rays, one reflected and the other refracted; as, for
instance, the ray B 0 into the reflected ray GB’, and
the refracted ray on" ; or n 0 into the two rays 0 n’
and c D". So, also, a ray B" 0 will be partly reflected
in the direction 0 n’, and partly refracted into 0 B; or
1)" 0 will be reflected into o d’, and refracted into 0 1).
Now, in all these cases, the three rays, incident, re-
flected, and refracted, will be all in one plane, and
that plane perpendicular to the acting surface A A.
The angles of incidence
and reflection (such as
run and 201)’) are,
as already explained,
invariably equal; but
that of refraction (in this case r’ o D”) is dif- ' ‘
ferent from both, but
connected with them “
by this law, that (at
the same surface) the
sines1 of incidence and
refraction, to the same radius, bear a constant ratio
to each other, which is always the same in the same
two media. For instance, in passing through the
surface A A, at whatever degree of obliquity, and
whether upwards from the water into the air, or
down from the air into the water, a ray is invariably
so bent that the angle it makes with the perpendicular
1? r’ in the air may be greater than that in the water,-
and that the sine of the angle in air may be to that
in water (to the same radius) as 41 to 3, which is the
ratio that has been determined by experiment. At
the surface separating any other two media, a dif-
ferent ratio would be observed with equal constancy.
If we want to find the new direction into which
any ray, such as D 0, will be bent by this surface, we
draw a circle round the point 0 with any radius, such
as o s, and we find the sine of the ray in air (to this
radius) to he s 8. Therefore the sine in water will be
*2- of s s. Draw a line parallel with o r’ at a distance
therefrom equal to £— of s s, viz. at the distance 3’ s”,
and as this intersects the circle at s", we know that
the refracted ray must pass through s" to make its
sine in water (3’ s") ~2— of its sine in air (s s) both to
the same radius (0 s or cs"); If any other radius
had been chosen, as ea, it is plain that we should
have obtained the same result; for, by the property
of similar triangles, if s’ s" be 3°’; of 83, then s's" is
also :2- of as.



Fig. 1320.

(1) The sine of an angle is any line dropped from a point in one
of its legs perpendicularly to the other leg, and may therefore
have any length. Thus, the sine of P on (Fig. 1320) may be either
s s or $8, or any other line parallel with them, intercepted by the
two legs of the angle P c and on. The sine to a given radius is
found by drawing a circle with that radius round the angular
point, and from wherever this circle crosses one leg dropping a
perpendicular to the other. It can therefore only have one length,
and (in the same angle) will always bear the same proportion to
the radius, however long or short that may be. Thus the sine of
the angle r on to the radius c s is s s, but its sine to the radius
0 s is as.
158
LIGHT;
If we were tracing the course "of ca ray'eupwards
from the water, asn" c, then, having found its sine
in water to any fixedrradius, we should make its sine
in air a greater, because the sine in is always
greater than that in water, as 41': 3 ;' and we "should
thus find the new direction'of the: ray to be on. In
this case a ‘very singular efl’ect would take place the ray were very-oblique to the surface, as r to. We
should first remark 'thatu'o ray passing ‘from the air
into thewater, ,however obliquely, could ever i be’ ‘re-
fracted into- ?the- direction for this"reason=-—The
sine of- no ianglecan- be :greater' than. the radius to
which it is drawn; therefore no‘ ray can have‘ its‘ sine
to radiusjcs greaterithan o s. But its sine in water
is. only-5’; of that ‘air, :and consequently cannot
exceed ~2- of the radius. .Now, the sine of the ray 0 r,
viz.frz,' ismore than—Z; of the radius cs ; therefore
no degree; of obliquity Toff, the ray in will enable it
to'become so oblique in the water as c 1:‘. But a ray
may ascendin the direction no as well as in any
other. Now‘, its sine in air must become “lg greater
than rz ; but this is impossible, for. a line % longer
thanrz would be longer than. the radius 0 s, and
therefore too long to be the sine of any angle to that
radius. As this ray, then, cannot be refracted accord-
ing to Me law, it- is not refracted at all, but totally
rcfleclecl in the direction of; the only known instance
of total reflection, for none of the light can penetrate
the surface A A, which is, in fact, absolutely opaque to
this light. This phenomenon ,of total reflccliou may
be seen: by looking‘ through the. side of a tumbler con-
taining water'up' to its surface, in'some such direction
as fc, when the surface willv be seen to be opaque,
and : more reflective than any mirror, inasmuch as the
images" in it are perfectly equal in brightness to the
objects themselves. ‘
At the surface between any other two media, the
ratio of the sines-would'be different; for though all
surfaces reflect alike (as regards the direction of the
ray), all do not refi'ael alike. Suppose the ray passed
from vacuum into water, the ratio would be rather
greater than 3 :4:, namely 1 :1'335. In passing
from vacuum into air of the common density, the re-
fraction would be much less, and consequently the
sines much more nearly equal, viz. as 1 :1'00029i.
Now, if the sine in any medium be called 1, the cor;
responding sine in vacuo is called the‘ iuclea' 0y" refrac—
i‘iou of that medium; and is specific for each sub
stance, or as constant as its density, expansibility,
specific heat, or any other measurable quality. Thus
the‘ refractive index of air of the common density is
1000294, that of water 1335, of crown. glass 1'52,
of 'flint- glass'1'5'5'. Now, in the case above considered
“of refraction from air into water, and vice versa”, the
since in air and in water are, strictly speaking, as
"1'33'51-170002941; and generally the sines on each side
jof, any; surface; are inversely as the refractive indices
‘of the twohmedia. , The refractive indices of a great
many :media'have been measured and arranged in
tables. _‘ ~ When the‘ ‘density of any substance is ,crea‘sed or diminished, its, refractive power is increased
or diminished in the same ratio. In these tables it

’ will"beyobservedtfiast,"that. thevindex of everymedium
is“ greater: than 1,» because the sine iv? vacuo. is. always
gireater‘than. in; any-'medium which has been exam?
ined: secondly, that few gases or vapours have a
higher index than 1001; few liquids lower than 1'33 5,
whichis the indeixjfor-water, and none higher than
1'7 I; ‘no solids, unless they contain fluorine, lower
than~1"51, with the .exception of ice, which is only
131; and-none r higher than 16, except the gems,
whichvary up11=96 ;- sulphur which is 2'15, phospho_
rus 2'22.~ The .diamondis 2441, being the most re-
fractive of transparent bodies, although it is exceeded
by a few deeply coloured almost opaque minerals.
It is commonly said that both refraction and re-
flection occur at such surfaces only as separate media
from different‘ densities. But this must be under-
stood- of oplical density,1 which is by no means pro-
portional to mec/zauical density, at least in different
substances; for although a change in the density of
any medium causes a proportional change in its re-
fractive index (as when water expands on becoming
ice, and has its index diminished from 1335 to 1310),
yet this by no means applies to different media; for
water, which ‘is much denser than oil, is much less
refractive. By reducing the refractive indices of
bodies in order to ascertain their ratio if they were
all of equal density, we ‘are enabled to compare their
alsolule refractive powers, which ‘are found to be
closely connected with their chemical properties ;
auious, or electro-negatives, having always the lowest
refractive: power; and cations, or electro-positives, the‘
highest. Refractive vpower seems to be-the only pro-
perty except weight, which is unaltered by chemical
combination; so that by knowing the refractive
powers of the ingredients we can calculate that of
the compound.
The application of the laws of refraction accounts
for numerous deceptive effects seen in the atmosphere,
and included under the general term mirage ; the
most familiar of which is the distortion of objects
seen through a risingcurrent of hot air, which, from
its smaller density, has a lower refractive power than
the surrounding cold air, and therefore bends the rays
in various directions. It is also plain that the rays
of the heavenly bodies coming from space into our
atmosphere must be refracted, and thus cause the
objects whence they come to appear rather above
their true place, as the eye at cl, in Fig. 1320, secs 1)
in the direction al 0, rather above its true place.
This forms one of the sources of error to be allowed
for in all astronomical observations; and tables are
calculated for "finding its amount, depending on the
(1') As it is possible to find two substances which, though '(very
different in .theirnature, have-nearly or quite the same optical
density, light willpass fromv one into the other, unrefracted and
unreflected, and the surface between them, however rough, will
be transparent ‘and invisible. ~ This remarkable effect may be seen
by plunging ‘ground (fir-powdered glass into a mixture of the oils
of turpentingane aniseed, in such proportions as to have the
same‘ refractive power as glass; or, by rubbing ground glass with
wax, which, by filling up its hollows, will render it transparent.
This ‘is alsoxthereason that paper, by being wetted or ‘oiled, be-
comes less white and more transparent, reflecting less light and
transmitting‘ more. The mineral called ky'drophane is another
exarriple;v " -~ ‘ - - .

LIGHT.
159
apparent altitude of the object, and the state ,of the
barometer and thermometer. Owing to the very
small refractive power of air, however, this error is
hardly sensible when the object is high, but increases
rapidly towards the horizon, where it becomes 33',
or rather more than the sun’s or moon’s diameter, so
that these bodies may appear just clear of the horizon
when they are completely below it. As the density
of the air diminishes. gradually upwards, atmospheric
refraction is not, like that which we have just con-
sidered, a sudden change of direction, but the ray
actually describes a carve, being refracted more and
more at every step; and this applies equally to the
light from a distant terrestrial object which is either
lower or higher than the eye, because it must pass
through air of constantly increasing or diminishing
density. This refraction has therefore to be allowed
for in LEVELLING, which is done by assuming that
the light from a distant object comes to us in a line
arched or curved upwards, the radius of which is
about seven times that of the earth.
The application of these laws of Dioptrics has also
led to the understanding of the mechanism of the eye,
and hence to the imitation thereof by lenses, affording
the remedies for its infirmities of long and short sir/lit,
and disclosing the wonders of the telescope and the
microscope.
In order to understand the action of lenses, we
must remember that, as a lens has necessarily lzeo
refracting surfaces, the direction taken by a ray
after passing through it must depend mainly on the
relative inclination of the two surfaces to each ol/zer
at the points where it crossed them. Sometimes one
surface partly or wholly undoes the effect of the other,
and sometimes adds to that effect.
Let us first examine, then, the progress of light
through a piece of plane or parallel glass, of equal
thickness throughout. Let AA and-B B (Fig. 1321)
represent portions of the two surfaces of such glass,
and let a ray from B. fall obliquely on the surface A A
at a. To find tne new direction it will take, we must
first draw pp through the point a, perpendicular to
the refracting surface an. Now, by the first law of
refraction, we know that the refracted ray will be in
the same plane which contains the incident ray nn,
1: R and the perpendicular r r.
/ In this plane, therefore, and
’ with any radius, we draw a
I" we circle round the point a,
I and we find the sine of in-
. ‘y cidence to be a'. Now, by
referring to the tables, we
find the index of the re-
fraction of glass to vary
from 1'521 to 158, ac-
cording to the leind of
glass. But, for simplicity
sake, we may suppose it to be generally about 1g
times that of air. Therefore the sines in air and
in glass (to the same radius) will be as 3 : 2; and
by making the sine in glass (viz. p) equal% of .r,
we find the new direction of the ray to be a l, meeting

"D M



Fig. 1321.

the second surface BB at 6. Here we erect a new
perpendicular r’ P’, and draw a new circle, which is
obviously in the same plane with the former circle
round a, and (supposing both circles to be equal) it
is plain that the sine p’ in the second circle is equal
to p in the first. Now, the new sine in air (viz. a’)
must be 1% times the length of p’ or p, and therefore
will just equal the original sine cc.‘ Hence we see
that the emergent ray 6 n’ will have the same direc-
tion as the original incident ray n a, though not in
the same line with it. Thus we see that a ray can
suffer no permanent change of direelion by passing
through a parallel-sided plate of any medium, although
it suffers a small lateral displacement depending on
the thickness of the plate, which displacement may be
easily seen in viewing this page through a piece of
this]: glass.
This property of parallel-sided glasses, by which
their second surface exactly undoes the refractive
effect of the first, renders them so well adapted for
windows. But by the same reasoning which shows
us that two parallel surfaces will compensate each
other’s effects, we shall also see that, to produce this
compensation, the surfaces must be parallel; so that
glass of unequal thickness displaces and distorts
objects seen through it. Any glass having two plane
surfaces, not parallel, is called a prism ,- and it per-
manently alters the direction of every ray passing
through it, the change being greater in proportion as
the inclination of the two surfaces‘ is greater. On
looking through it, all objects are seen removed from
their true place towards the base or l/iielrer part of
the prism, whether that be turned upwards, clown-
wards, or to either side.
But however much a prism may change the general
direction of each pencil 2 of light that passes through
it, it can effect no change in the relations of the
various rays which compose each pencil. These all
proceeding from one point necessarily diverge, but
the further we recede from their point of origin, the
less divergent will any small portion of them be; and
when the point is at a vast distance, as in one of the
heavenly bodies, all the rays of each pencil may be
regarded as parallel, although the different pencils
have different directions. '
Now, no plane surface or combination of plane
surfaces can ever increase or diminish the divergence
of a pencil passing through them, still less render a
divergent pencil parallel, or nice oersd; and as in the
eye and all other optical instruments it is necessary
that this should be done, and even that they be made
to converge and meet or foealize in one point, and

(l) Technically called the refracting angle.
(2) Pencils of light are so called from their property of painting
on a screen an image or picture of the points whence the pencils
originally came. This resemblance is not seen in any one point
alone, but when the other pencils, proceeding from all the sur—
rounding points of the object, are each separately concentrated on
as many different points of the screen, all these points or fan’
shine with the same qualities and intensities of light, relatively
to each other, as did the corresponding points of the object; so
that they must form an exact picture thereof, such as is painted
on the retina of the eye, and in that beautiful toy the camera
obscu-ra, which is an imitation of the eye. -
160
‘LIGHT.
again diverge therefrom as from a new source, ad-
vantage is taken of the refractive effect of the carvecl
surfaces of convert and concave‘ lenses. It is obvious
that a pencil of parallel rays meeting with a curved
surface must all have different inclinations thereto,
and consequently all must undergo different amounts
of refraction, so that they can be no longer parallel
after passing through the surface. Now, whether
they be entering or ‘emerging from the surface, that
is, whether they pass from va‘ rarer medium into a
denser,1L or vice versa'; in either case they will be
rendered divergent if the surface of the densermedium
be concave, and convergent if it be ‘convex. Let us
further inquire into the opposite effects produced by
these surfaces upon a single pencil of light, the rays
of which are not parallel,’ but either divergent, or
already rendered convergent by the action of some
other surface. _
First. By convex surfaces every pencil already
convergent is rendered still more so. Thus the rays
B (Fig. 1322), proceeding through a convex surface
to A, are made to converge more ‘quickly than before,
so as to focalize sooner than they would otherwise
.\ p. ‘ ~ -.\





\\
s\\\
\ ' is
Fig. 1322. '
have done. With regard to divergent rays, they are
at least rendered less divergent by passing through
this kind of surface. Thus the rays at A passing to B
have their divergence diminished. But in certain
cases, viz. when their originaldivergence is not too
great, it may be altogether destroyed, and they may
be rendered parallel, as the rays 13 proceeding to 0 5
and if their divergence had been still less, or the
surface more convex, or the medium more refractive,
they might at once be changed from a divergent into
a convergent pencil, . as the rays from B passing
through two convex surfaces to 1), become convergent,
an effect which might have been produced by a single
surface, if it had been sufficiently powerful.
Secondly. By concave surfaces, on the contrary, a
divergent pencil is made to spread still faster, as in
going from B to A, Fig._l323. I
‘-
\~\\\~ ~ .


_\ ~‘




Fig. 132s.
pencil has either its convergence diminished, as from
A to B (thereby delaying its focalization, though not
preventing it), or its focalization is prevented by
rendering it a parallel pencil, as in passing from B to
c ; or if the surface be strong enough, the pencil is
changed from convergent into divergent, as by the
joint action of the two surfaces 13 and D.

(1) Optical density or refractive power is here meant, which is
not proportional to mechanical density in different substances.
For example, oil is mechanically rarer, but optically denser than
water.

This effect of convex and concave surfaces is not
so easily observed as- their magnifying and diminishing‘
power. To illustrate this, let us suppose that. the
lines at ‘A, Fig. 1322, instead of representing dif»
ferent rays from the same pencil, to be different
pencils coming from various points of a certain object
to the eye, situated somewhere beyond 13; as they
proceed from several points to one point, they must
be convergent. By passing through a concave surface
they are ‘rendered less convergent, and it is evident
that the eye’ will receive the top pencil as if it came
from a point" lower than that' of its real origin, and
the bottom pencil as if it came from a point higher
than it actually does. Thus the top and bottom of
the object will be seen nearer together than they
really are; and the sides being also..brought nearer
to each other, the object will appear to be oliminislzecl.
Let us view the lines at :B, Fig. .1323, in the same
manner as representing distinct pencils, but 'pro-
ceeding through a convex surface to an eye placed at,
or beyond A. As their original convergence is in-
creased ‘or hastened, they all enter the eye as if they
cameifrom points more distant from each other than
is actually the case,‘ and hence the object appears to
be magnified. This ‘magnifying effect is, however,
too small to be turned to any useful account, and
must not be confounded with the magnifying power
of telescopes and'micros'co'pes, which, although pro-
duced generally by ‘the combination of convex lenses,
depends not at all on this last—mentioned principle,
but on an application of that first described, viz. their
action ‘on the different rays of the same pencil, not
on different pencils.
These details will enable the reader to understand
something respecting the mechanism of the first of
all dioptric instruments, the eye, and the use of
spectacles; as‘ also the principle of ae/zromatisnv. It
will be seen that in every respect the action of convex
and of concave media (in vacuolis opposite, the former
constantly tending to focalize light, and the latter to
prevent or retard its focalization. For the sake of
brevity let us call the former effect positive, and the
latter negative; There is also this advantage in doing
so ;.for as the surfaces of lenses generally separate one
medium from another, and not from a vacuum, one
medium must-always be convex and the other concave ;
but:we call the surface convex or concave according
as the elen'ser, or rather the more solicl medium is. so.
' Now in this sense, a convex surface does not always
produce the positive effect, and vice versct; for let a
convex lens‘ or magnifying-glass be immersed in oil
of aniseed or of cassia, and it will act as a concave
lens or diminishing glass 3 for these oils, although
mechanically rarer, are optically denser than glass, so
that the lens acts as a partial vacuum in the oil, and
its convex ‘surfaces have. less effect than the concave
surfaces of the oil. For the same reason, a concave
lens plunged into these oils will magnify. This con-
fusion between the mechanical and optical meanings
of the terms convex" and concave, may be avoided by
substituting the terms ‘positive and negative-
The eye consists of a spherical box, into which the
LIGHT.
161
light is admitted through a hole, called the pupil,
and passing through three transparent media, called
lianzoars, all separated by positive surfaces, the light
is by their action focalized (each pencil to a different
point), in the neiina, or screen of nerve, which is
spread out on the back of the box to receive and
perceive them. . Hence it is evident that the rays of .
light must form on this screen a picture similar to
that in a camera obscura, and to produce distinct
vision the picture must be distinct, that is, the rays
of. each pencil must neither focalize and cross, before
they arrive at the retina, nor yet arrive there without
focalizing; for in either case they will not be separated
from every other pencil, for they will not be con-
centrated on one point‘, but be spread over a small
circle, so as to mingle with the surrounding pencils.
Now these are the two opposite defects, called long
and short szgll, which are corrected by placing before
the eye a positive or a negative lens, the former
accelerating and the latter retarding the focalization
of the rays. The short-sighted eye overdoes its Work,
for it focalizes the rays of each pencil too rapidly,
and thus separating all the pencils too soon, allows
them to mix again before arriving at the retina. This
may be remedied in two ways; first‘, by bringing the
object very near, so that the rays received from each-
point may be more divergent than usual, and may
therefore converge less quickly after refraction by
the humours of the eye; or seconellg, by looking at
distant objects through a negative lens, by which the
rays of each pencil naturally almost parallel, are
rendered divergent, as if they came from a nearer
object, and are therefore, as before, more slowly
focalized.
The long~sighted eye fails to effect the complete
separation of the various pencils, before they reach
the retina, unless they come from a very distant
object, so as to consist of nearly parallel rays, which
require less refraction to focalize them, and are, there-
fore, sooner focalized than the more divergent ones
coming from nearer objects. In order to focalize the
latter, the eye must be aided by another positive
lens, in addition to its own positive surfaces, which
are not sufficiently powerful.
A healthy eye cannot see objects distinctly nearer
than 6 inches, because the rays of each pencil are
too divergent to be focalized soon enough to give a
distinct picture on the retina. This may be remedied,
therefore, by an extension of the same principle
applied for the correction of long sight, viz. by
helping the eye to focalize these pencils by the aid of
a positive lens, which performs part of the work,
and leaves the other part to be done by the eye.
Thus, by using a lens powerful enough, we may see
almost as near as we please, even at -};th or gth of
an inch. Such a lens, applied at once to look at an
object, forms a simple microscope, and when used for
looking at the optical image formed in a compound
microscope, or in a telescope, it constitutes the ege-
glass of those instruments.
No healthy eye can see very distant objects, such
as the heavenly bodies, distinctly through a positive
voL. II.

lens, however small its power, because the rays of
each pencil, already parallel, are by the lens rendered
convergent, a state which they never can have in
nature, and which the eye is no Way fitted to receive,
for being already partly focalized, this work will be
completed by the eye too soon, and they will cross
before arriving at the retina.
From all that has been said, it will be evident that
a positive and a negative surface of equal power will
neutralize each other, as in a ioalc/i-glass, which has
just the effect of a plain glass.
The focal length of a surface or lens (if positive)
means the distance at which it» will focalize a pencil
of previously parallel rays, or at which, therefore, it
will form on a screen a distinct picture of any very
distant object, such as the sun. This is also the
distance at which it must be placed from the source
of any divergent pencil, to render it parallel; con—
sequently, the greatest distance at which objects can
be seen distinctly through it; for if they be removed
further, the rays of each pencil, falling on the lens
with less divergence, will be rendered convergent, and
therefore unfit to afford distinct vision.
But the focal length of a negative surface or lens is
equal to that of such a positive one as will just
neutralize it, and produce the efiect of a plain glass ;
or it is the distance at which a pencil, which it
renders parallel, (or just prevents from focalizing,)
would have focalized, if not intercepted by it.
Now the focal length of a spherical surface,ll whether
positive or negative, depends jointly on its radius,
and on the ratio between the refractive indices of the
two media; but if this ratio be as 3 to 2, (which those
of air and glass are very nearly,) the focal length of
any surface is izoiee its radius.‘
All the complex rules commonly given for finding
the combined focal length of two surfaces, or that of
the different kinds of lenses, [see LENs,'] may be
dispensed with by attending to the following simple
principle :-—The eficls of surfaces are inoerselg as
their focal lengths, and the combined effect of two
similar surfaces must be the sum of their separate
effects, while that of two dissimilar surfaces is the
difference of their separate effects. Therefore, the
combined focal length of two similar surfaces is the
reciprocal of tile sam of Me reciprocals of their separate
focal lengths. Thus, to find the focal length of a
lens whose surfaces have the focal lengths of 6 and
41 inches, both being positive or both negative 3 add
their reciprocals, viz. {a th and ,-1,th, which gives pg the,
the reciprocal of which is %%ths, or 2'4 inches, the
answer. But if one surface were positive and the

(1) The surfaces of lenses are always spherical, because it has
not yet been found practicable to give them any other figure
accurately. [See Luisa] But it can be proved that they ought
to be sometimes portions of oblong spheroids, and sometimes of
hyperboloids, according to the purposes for which they are in~
tended. In consequence of their not having these forms, they
focalize imperfectly, which defect is called their spherical aberra-
tion. By observing particular ratios, however, between their
curvatures, although spherical, their errors may be made partly
(or in some cases Wholly) to compensate each other; and this is
one of the chief objects aimed at in the construction of the best
class of telescopes.
M
162
tier-n‘.
other negative, (as in a periscopic lens,) subtract %th
from ~33; th, which leaves Tlfith, the reciprocal of which
is 12 inches, the answer. '
We see, then, from the foregoing details, that when
the various pencils coming from any object are
separately 'focalized in different adjoining points of
space, these points form a repetition or image of the
object suspended in space, ‘and differing ‘from a real‘
object only in this ; that each point of a real object‘
radiates a splzere of light, so as to be'seen in every
direction, whether the eye be above, below, or on any
side of it; while each point of an optical image
radiates only a eoue of light, so as to be'seen only by
an eye placed in that cone. ‘
We have seen how this image may be larger or
smaller than the object, and may be brought as near
to us as we please, so that we may examine detailsin
it which are invisible in the real object, on account of
its distance. The image formed in the compound
microscope is larger than the object ; in the telescope
it is incomparably smaller; but in both it is brought
very near to the eye, too near to be seen without
the intervention of an eye-glass, the action of which
is, by combining with that of the lenses of the eye
itself, to render it for the time unnaturally short-
sighted; for by adding other lenses to its own, the
eye can be made to see at the distance of an inch, or
even {6th of an inch, as in using a simple microscope
already alluded to.
Although refraction is a property common to light
of all kinds, yet this property is not possessed equally
by different kinds of light. As sounds differ in many
respects ‘besides loudness, and as radiant heat (apart
from any difierence pf intensity,) differs in the
qualities .of refrangibility and absorbability by dif-
ferent media, so also do rays of light differ in the
degrees of these same qualities, independently of their
difference of brightness; and these difi’erences, in so
far as they are distinguishable by the eye, constitute
colour. Differences of quality, not distinguishable by
the eye, constitute polarizatz'eu.
The law of refraction, that the sines of incidence
and refraction always bear the same ratio at the same
surface, is true only as regards rays of the same colour,
‘or coming from objects of the same colour. Moreover,
light, which we call colourless (as that coming imme-
‘diately from the sun), really contains light of all
possible colours so mixed as to neutralize each other.
This capital discovery was made by Sir Isaac Newton
in the follow-
ing manner :——
Having closed
the windows of
his apartment,
he made a
small hole in
the window-
shutter, so as
to admit a sun-
beam K, Fig.


Fig. 1324-.
13211, which, proceeding in a straight line, illuminated
a spot on a screen placed to receive it at A. Now,‘

by means of a prism, which we have seen efi’ec‘ts a
permanent change in the direction of the light that
passes through it, we can turn aside this sunbeam in
every direction. Thus, if the base of the prism be
downwards, the beam will be turned downwards; but
a prism turned base upwards, as at P, will refract the
‘beam upwards, so that it will no longer illuminate the
spot A, but some spot much higher, as 8. Now, it is
very remarkable thatthis spot s, instead of being simi-
lar to A in shape, is greatly elongated, its breadth re-
maining unaltered; and, whereas A was colourless, the
lengthened spot s exhibits a continued gradation of
the most intense ‘colours, the lower end being reel,
_which passes upwards into orange, this into yellow,
then green, blue, z'uctz'go, and violet, which is at the
upper end. The 'very same colours will be seen, and
in the same order, whatever way the prism may be
turned; for, whether the spot s, which is called the
prismatic spectrum, be above, below, or on either side
of A, its red end will always be uearest, and its violet
end furt/zest from A.
Hence we see that the various rays composing the
parallel pencil n do not remain parallel after refrac-
tion, even by two plaue surfaces (contrary to what
has been advanced ‘Fig. 1321), and consequently these
rays must have suffered llzjereut amounts of bending,
though falling on the prism under precisely similar
circumstances; and this will be found to be true also
in every other case of refraction, whether produced
by a prism or a single surface, and whether by glass
'or any other solid or liquid medium. The same rays
that are most bent by passing from air into glass are
also most bent in passing from glass into air, or into
water, or any other medium, and are therefore said to
be the most re/‘raugz'ble.
Moreover, it appears that the rays which are least
bent are always real, those most bent always violet, and
the others of intermediated colours, though before
separation they were colourless. It became aninte-
resting question, then, whether, if reunited, they
would again compose colourless light; and this New-
ton proved by many convincing experiments, the most
complete of which perhaps consisted in receiving the
divergent beam at s, on a convex lens, when the focus
at which all the coloured rays met was found to be
perfectly colourless. -_
If, however, in this last experiment, the lens be not
wide enough to include the Made of the coloured
beam, or if a portion thereof be purposely intercepted,
the focus of the remainder will not be white, but
tinged with some colour, which will be pale if only a
small portiorz of the spectrum be thus intercepted,
but more decided the more of the spectrum be omitted
from its composition; and there is no colour, tint, or
shade, in the whole circle of nature or art, which
may not be thus exactly reproduced by a mixture of
part only of the components of white light.
. This important fact may be further shown thus.
If we look through a prism at some small zolzz'te object
or spot on a blue/e. ground, it will be seen not only out
of its place, but lengthened, and coloured with the
entire-series of prismatic colours, forming a complete
l'JIGHT.
163
spectrum, of which the red end’ is nearest the true
place of the spot, as seen without the prism. The
same will occur if the ‘spot be grey ‘or of a neutral
tint, showing- that, though it reflects less light than
"the white object under the same circumstances, yet it
reflects (the same kind of light, or a'mixture of the
same colours. In fact, a good neutral tint should
differ in no respect from a white less z'llnmz'naz‘ecl, so
that, by regulating the intensities of light which they
receive, they may be made to appear exactly alike.
But, if the object examined through the prism be
‘coloured, it will not be lengthened so much as the
white or grey object; for some portion of the spec~
trum, either one end, or both ends, or the middle, will
vbe missing, and the portion which appears will show
what portion of the ‘complete, ‘or solar, spectrum
must be focalized, apart from the rest, to imitate the
‘colour of this object.
Now, if the object here used be of a very pure
and intense colour, such as Vermilion or ultramarine,
it will scarcely appear elongated or at all
[Eli] changed in appearance, showing that all
' the rays coming from it are nearly of the
same kind and equally refrangible. But
Newton showed the different refrangibilities
of these two colours by the following very
simple and conclusive experiment. A little
half blue, as B n, Fig. 1325, was placed on
a black ground and viewed through a'
prism. When this was so turned as to see
the paper above its true place, as at B R,
the blue half was seen raised higher than
the red half, as here shown; and when
5 both were depressed below their true place,
F 1'9- 1325' as at 6 r, the blue was seen to be depressed
the lowest, so that in both cases it was more dis-
placed, 2'. e. its rays were more refracted than the red.
If this experiment be varied by using the two
colours finely powdered, and mixing them together so
as to appear purple, neither the red nor the blue
grains being distinguishable by the eye, the prism
will nevertheless effect their complete apparent sepa-
ration, so that, if the spot of purple be small, it will
appear divided into two distinct spots of red and olne;
but, if it be too large for its two images to be de-
tached, it will only appear fringed with red on the
upper edge and blue on the lower, or vice oersd, the
middle part, where they overlap, remaining purple.
On this principle, therefore, we may easily explain all
the coloured fringes seen to surround objects viewed
through a prism, a lens, or any other glass of unequal
thickness. All this is due to the deeomposilz'on of lz'y/zl
by refraction, in consequence of its rays having dif—
ferent degrees of refrangibility and different colours.
The ratio between the sines, in any two media,
being different for rays of different colours, it follows
that the index of refraction given in the tables above
mentioned for each medium only applies to rays of a
particular colour, those of the mean refrangibility,
or middle colour of the spectrum, viz. green. Thus
the index of water for these rays is 1335 851, but for
rectangle of paper, coloured half red and.

some of the violet rays it is more than 13414, and for
some of the red less than 1'330 ; and there exist
rays having every possible index of refraction (by
water) between these two extremes.
A similar difference, though not in the same ratio,
generally a greater, exists between the refrangibilities
of these rays by every other medium, whence Newton
concluded that the focal length of a curved surface,
or 'of a ‘lens, must be different for different colours,
and that, as‘the light of- most objects contains rays of
various refrangibilities;~it cannot be truly focalized to
one point by any lens, ‘thus accounting for the confu-
sion of colours seen at the edges of the image
formed in a telescope, which confusion, and conse
quent indistinctness,'was at that time the greatest
obstacle to the progress of astronomical discovery.
He tested the truth ofwthis conclusion by the follow-
ing simple experiment, among many others :—-~
Let A B, Fig-‘1326, represent two candles, and L
a convex lens ‘placed at an equal distance from both,
viz. about twice its focal length, or rather less.
A pencil of rays from the candle A will be brought to




Fig. 1326.
a focus at ‘some point A’, where 'a white screen ‘must
be placed to receive it, and a pencil from B will like-
wise be focalized at B’ on the same screen. Now, for
the same reason that these foci are at different spots,
all the innumerable pencils cpming from the different
points of each flame will be concentrated on different
points of the screen, so as to form an exact image of
the candle, if the screen be at that precise distance
from the lens at which the rays focalize. As the rays
from the lower candle, however, go to the upper
image, so those from the foot of each flame go to the
top of the image, and vice verse’, so that both the
images are inverted. Now, place before the two
candles a blue and a red glass, as b r, the images will
of course assume the same colours; but‘ it will now
be found impossible to place the screen in such a
position as to make boll images distinct. This can
only be ‘accomplished by receiving them on separate
screens, viz. the blue image on a screen a rather
nearer the lens than that which receives the red
image. They will then he more distinct than they
can ever be made to be without the coloured glasses.
If we point a common (non-achromatic) telescope
to a blue and a red handbill at a short distance, we
shall have to draw it out to a greater length in order
to read the red than the blue bill. But with this pre-
caution both can be read at a greater distance than a
white bill. The same difference will be observed in
looking at the sun with a blue or a red darkening
glass. '
= For the same reason the focus of a burning-glass,
which is in fact an optical image of the sun, is never
perfectly distinct, but always confused by a blue or a
it 2
1641
LIGHT. "
red border, because the various coloured "rays of
which sunlightis composed cannot all be focalized at
once.
As the same cause for imperfect focalization exists
in every refractive medium of which a lens could be
formed, Newton concluded that'no good telescope
could be made on the vdio'ptric principle, and that the
only perfect focus would be that formed by reflection
from mirrors or spe'cula, as explained in the case of
HEAT, Fig. 1137; ‘for the law of . reflection, unlike
that of refraction, is the vsame for all rays, of what-
ever colour. He therefore turned his attention to
devising a telescope that should act by rq/lection, and
soon invented that noble instrument by which, almost
without a change, except in size, the latest discoveries
of Herschel and Lord Rosse have been made.
But we owe this grand invention to an oversight
of Newton; for soon after his death it appeared,
from a closer examination of the phenomena of colour
by Euler and others, that what Newton had regarded
as impossible, viz. refraction without dispersion of
colours, was possible; and ‘ another Englishman,
Dollond, had the merit of first accomplishing this by
an application of the same abstract principle which is
displayed in the compensation pendulum, and may be
thus exemplified. Although we can find no metal
which does not expand by heat, so as to be no longer
in summer than in winter, yet, because all metals do
not expand in the same ratio to their entire length,
we can so combine them as to form a 'pendulum
whose length shall never vary; for its length can be
made to depend on the digference between the lengths
of two bars of different metals, which, though of
unequal lengths, may yet expand by an equal incre—
ment, for the same increase of temperature, so that‘
their difference may remain invariable. . In the same
manner, although we know of no solid or liquid
which refracts all the colours equally, and although
the same colour which is most refrangible by glass is
also most refrangible by water, oil, or any other
medium, yet, because the' ratio between the refrac-
tions of the most and least refracted rays is not the
same for every medium, we have the means of so
combining two media as to refract all the colours
equally. For instance, a certain kind of plate glass
is found to bend the most refrangible violet rays
always glgth more than the least refrangible red rays.
This is expressed by saying that its dispersive power
is 'éLO-tll, or 0033. Suppose we have a kind of flint
class, which bends the violet rays 515 th more than the
red, or has a dispersive power of 005. It is evident
that, if we make a prism of each kind of glass,-with
such shapes that both shall bend the rays equally,
say 30° out of their direct path, both will not form
spectra of ‘equal length; for one spectrum will be glath
of I the whole refraction, or 1° long, while the other
will be g-Igth, or 1—§-° long. But let the two prisms have
suehshapes that, while cne of them (the flint) refracts
the ray 20°, the, other (the plate-glass) shall refract
it_'30°'; ‘then’ both will produce an equal dispersion of
1°.‘ Consequently, if both' be placed together in
such positions 'as' to refract in ‘opposite directions

(one 30° to the~ right and the ‘other 20° to the left),
the latter will not undo the refractive effect of the
former, but will leave the ray still bent 10° to the
right, and yet their dispersive effects, being each 1°,
will entirely compensate each other; so that a re-
fraction of 10° will be produced without any disper-
sion at all. The same principle is applicable to any
other refracting instrument, such as a lens ; and thus
white or other mixed light is focalized without sepa-
rating its component colours, and lenses are made to
give an achromatic 1 image as well as mirrors.
Experiments and computations without end have
occupied Opticians, ever since this discovery, to find
what materials and what curvatures in the lenses of
a telescope will render it most nearly aplanatic, or
free both from .the chromatic and all other errors.
On the whole, refracting telescopes are now brought
to greater perfection than reflecting ones, although
they cannot be made so large?
We have seen, then, that the different qualities of
light which we call colours all exist in common solar
light, and are separated therefrom by virtue of their
possessing different degrees of refrangibility, and also
of absorbability by material media. The order of their
refrangibility is the same in all media, but that of
their absorbability is different in each medium. Some
media have no preference for one quality of light
more than another, but absorb them all equally ; such
are called neutral or colourless ,- the quality of colour
in bodies is due to the preference they have for light
of certain refrangihilities rather than others, so that
the least absorbable rays are left either to be reflected
from their surface, or transmitted through their sub-
stance to a greater depth than the more absorbable

(l) Aclzromatic (from a, not, and xpa'lna, colour), having none
besides its proper natural colours ; no rainbow-like fringes.
(2) The largest achromatic telescopes, such as those at Dorpat
and Kensington, have each a clear opening of 13 inches, while
that of Lord Rosse’s reflector is 6 feet. Taking the diameter of
the pupil of the eye at -,’;-th inch, the former instruments admit
10,816 times, and the latter 331,776 times the quantity of light
which is received from any object by the unassisted eye. But as
every speculum absorbs about half‘ the light that it receives, the
latter number must be reduced to 165,888. These numbers, then,
show how much the area of any object may be magnified by these
telescopes without rendering it less bright than it appears to be to
the naked eye; and their square roots, 104 and 407, show their
magnifying powers in such a case. We may also, from the size of
the aperture of any other telescope, estimate what is called its
absolute or penetrating power, which is independent of its length
or internal arrangements, and depends solely on the size of the
object glass. The number obtained by the above rule shows how
many times further any object can be seen with the telescope
than without it, supposing its brightness to remain the same at
all distances, as it does in vacuo. The magnifying power is
totally independent of this, and can be made asgreat as we please,
however small the telescope; but it is obvious that as long as the
quantity of light admitted is the same, the more the image is‘
enlarged the fainter will it be, its brightness being always propor-
tional to the quotient of the absolute power divided by the
magnifying power. ‘If the latter exceed the former, as it does in
astronomical telescopes, the object will be less bright than to the
naked eye; but if the, absolute exceed the magnifying power, the
object will be seen brighter with the telescope than without it;
this ‘is an essential condition in‘what are called night-glasses.
The magnifying power of a telescope may be found by pointing
it to a brick-wall, and fixing it very firmly. By looking with one
eye through the telescope, and with the other along its side, we
may count how many ‘courses of bricks seen by the naked eye are
comprised in th‘ehei'ght of one course seen through the telescope.
LIGHT.
.165
rays can penetrate; and in either casewe name the
colour of the body after that of these least absorbable
rays. Thus, red glass is so called because it allows
the red rays to penetrate through a greater thickness
of it than the other rays 5 but at a certain thickness
even the red rays would be all absorbed like the rest,
and we should call the glass black. So, also, with the
reflected colours of bodies which are generally, though
not always, similar to the transmitted ones.1
That no body, unless self-luminous, can appear of
a colour not existing in the light that it receives, will
be abundantly proved by observing the appearances
of coloured bodies held in the rays of the prismatic
spectrum. It will be found that no such body can
ever appear of a different colour from the rays that
fall on it, though it may appear of any s/zacle of that
colour, even down to llaclc, if it has not the property
of reflecting any sensible quantity of light of this
particular refrangibility. Thus the flower of a scarlet
geranium held in the green rays and receiving no
other light cannot be distinguished from black velvet.
IIence, if a room be illuminated with light of one
definite refrangibility, all distinction of colour in that
room will be lost, and the most brilliant and variously
coloured objects will all appear in mere slzacles, as in
a drawing. Such light may be obtained from a lamp
fed with a solution of common salt in alcohol. Now,
if into a room so lighted there be thrown a few rays
of common light, as, for instance, from a dark lantern
with holes in it, the spots on which they fall will
appear in their natural colours, like spots of bright
colours sprinkled over an Indian-ink drawing.2
It is doubtful whether any source of light, how-
ever, emits rays of only one definite refrangibility;
generally speaking, it includes rays of every possible
degree of refrangibility, within certain limits; but in
the above case these limits are very narrow. In the
light of other artificial sources they are wider, and
widest of all in solar light, which includes not only
all the colours visible to the human eye, but also rays
both more and less refrangible than any that affect our
optic nerve. These rays are accordingly invisible to
us, and have only been discovered by their effects on
other bodies. Those which are more refran'gible than
violet light are detected by their action on photogra—
phic preparations, and by producing other chemical
changes, whence they are called the chemical rays.
[See PHo'roGRAPHYJ Those rays which are less re-
frangible than any visible rays (even the red) have all
the properties of radical [zeal coming from bodies of a
lower temperature than 800° Fahr. Such heat is less
refrangible than red light, and we have ah'eady seen
that common radiant heat, like common light, is a

(1) There is a kind of glass common in the shops which trans-
mits orange but reflects green light; and another whose trans-
mitted colour is yellow and the reflected colour blue.
(2) In such a. light, the absence of all distinction of colour will
not hinder us from performing all the most delicate oflices of
vision, as reading, working, drawing, or shading a drawing;
whence we may understand how such operations are performed
by those who have‘ the singular defect of colour-blindness, or in-
sensibility to difi‘erences of colour. as was the case partially with
Dr. Dalton, who could only distinguish the fruit of a cherry-tree
from its leaves by their form.

mixture of rays of various refrangibilities. Now, if
the temperature of a radiating body be increased, it
emits, in addition to the rays previously . emitted,
others of a higher refrangibility, till, when it attains
the temperature of 800°, some few of its rays become
as refrangible as the least refrangible. rays of light,
and accordingly become like them visible, and affect
us with the same colour, so that the radiating body
is ‘then said to be reel-hot. If it be heated more, it
emits, in addition to the red, still, more refrangible
rays, viz. orange; then (at a higher temperature)
yellow rays are added, and so on, till, when the body
is while-hot, it emits all the colours visible to us; and
in some cases (of very intense heat) even the invisible
chemical rays, more refrangible than the violet, are
emitted, though in less quantity than in the solar
rays. Thus light appears to be nothing more than
visible heat, and heat invisible light, their difference
being only in the degree of certain qualities, and in
the human eye being fitted to perceive one and not
the other, as the car can appreciate vibrations more
rapid than 16 in a second, and not less rapid ones.
Of the various rays composing solar light, the most
visible to the human eye are the yellow; but those
which have the greatest heating effect are the faintest
red, or rather those iizvz'sz'ble rays which are a little less
refrangible than the red. Hence bodies which absorb
the red rays become more heated by the sun than
those which reflect them; blue cloth, for instance,
becoming sooner hot than real cloth of the same depth
of colour.
The foregoing details (for which the Editor is
chiefly indebted to his “ Introduction to the Study of
Natural Philosophy,” published in Weale’s Rudi-
mentary Series) will assist the reader in under-
standing the principles on which a variety of optical
instruments employed in the useful arts depend.
There are, however, certain practical applications of '
our knowledge of the laws of light and colour which
require some further notice. The assortment and
arrangement of colours in the arts and manufactures
is a subject which, notwithstanding its acknowledged
importance, has received but little attention in this
country. Persons who have a natural taste, an eye
for colour as it is called, are able so to group and
arrange the colours, patterns, and goods at their dis-
posal, as to produce pleasing and harmonious effects;
while others who are not so gifted, produce by their
arrangements a discord to the eye of the colourist,
which is analogous to the eflect produced on the
musical ear by instruments out of tune. The study
of the various phenomena of colour is a delicate, and
in some respects, a diificult one; but from the time
of Newton’s capital discovery of the compound na-
ture of light, the subject has engaged the attention of
scientific men. Among those who have laboured in
this important field with success, M. Chevreul is
eminent; and we propose to give a very brief sketch
of that part of his inquiry which relates to the in-
fluence which two colours may exercise upon. each
other when seen simultaneously. The reader who is
at all interested in the subject, will do well to
166.
LIGHT.
study Mi Olievreul’s large work, the title of which is
given below.1
It has‘ been already shown that a ray of white light
can be decomposed or resolved into seven coloured
rays : viz'. reel, orange, yellow, green, blue, indigo, and
violet .- that of these seven colours, the reel, the gellow,
and the blue, are simple or primitive colours, capable
by their. combination of forming wlzite light; the
other four coloured rays being formed by combina-
tions ofi two of the primary colours : thus, the combi-
nation of yellow and reel only produces orange; of
gellow and blue, green; while reel and‘ blue produce
violet. The rays comprised in the same group, the
reel rays.» for example, are not identical in colour;
they differ- more or less among themselves, although
the sensation produced by each one is known by the
term reel. .
When‘ light is reflected by an opaque white body,
the differently coloured rays are reflected in the pro-
portion to constitute white light ; but if light ‘falls upon
a body which entirely absorbs it, as in penetrating a
perfectly. dark hole, such body appears black, and
cannot be seen unless it be situated near other bodies
which reflect light to it. When light falls upon a
coloured. body which does not entirely absorb it, there
is always some reflection of white light, and of light
of the same tint as that of the absorbing body: if the
rays absorbed by the coloured body be united to the
colouredl reflected rays, they will form white light.
These reflected rays are said to be aeeielental or com—
plementarg to the absorbed rays, and difier with the
colour off the body'o'n which the rays fall.
If thebiue and gellow rays be absorbed, then the
refiectedl reel ray is the accidental or complementary
colour- -
If blueand reel be absorbed, gellow will be reflected.
If gellow and reel be absorbed, blue will be reflected.
If reel'b’e absorbed, green will be the complementary
colour‘ reflected.
If yellow be absorbed, violet will be reflected.
If, therefore, we wish to produce white light from
any coloured ray or rays, we must add thereto the
complementary ray.
Complementary colours may be seen by fixing the
eye steadily upon a coloured object, such as a'wafer
upon a sheet of white paper; a ring of coloured light
will play around the wafer, and this ring will be com-
plementary. to the colour of the wafer; a reel wafer
will give a green ring; a blue wafer an orange coloured
ring, and! so on. Or if, after having regarded the
coloured wafer steadily for a few seconds, the eye be
closed or turned away, it will retain the impression of
the waferggnot in its own, but in its complementary

(1) Dela Loi du Contraste simultané des Couleurs, et de l’Assor-
timent des. objets colorés, considéré d’apres cette loi, dans ses
raPPQrts avec la. Peinture, les Tapisseries des Gobelins, les Tapis-
series de Beau‘vais pour meubles,_ les Tapis, 'la Mosa'ique, les
Vitraux colorés, l’impression des Etofi‘es, l’lmprimerie, l’Enlumi-
nure, 1a. Decoration des Edifices, l’Habillement et l’Horticulture,
8vo., Paris,.1839,.witli an Atlas of Plates.
In the first volume of the Works of the Cavendish Society,
entitled “ Chemical Bieports and Memoirs,” edited by Professor
Graham, is a somewhat extended notice of Chevreul's researches,
under the title, “ Physical Investigations on Dyeing.”

colour. Thus, ~ a'- rill wafer will give a green spec-
trum, &c.
It is on the principle of complementary colours, that
two colours or two ditieren-t shades of the same
colour placed in juxtaposition heighten each other’s
elfects. For example, take two bands 0 and o’ of the
same colour
and identi-
cal, and two
other bands
1? and r’ of
another co-
lour and
identical; -
they must
be % inch
wide, and
2%— inches
long, and
they may be
formed of
stuff, paper,
ribbon, 8:0.
The band 0'
is to be
gummed to a card with 0 at the distance of 516th of
an inch from it; the band r is to be placed so as to
touch 0, and lastly r’ is to be gummed on at the
distance of 513th of an inch from 1?. Now, if we
look at the card in a certain direction, and during
some seconds, we shall generally see four eliferentlg
coloured bands. It will be observed that o’ and r’
serve as terms of comparision to judge of the modifica-
tions experienced by 0 and r in their juxtaposition.
1n the following seventeen observations, the colours
named in the left-hand column were arranged as
above; the colours named in the right-hand column
show the modifications which they experienced by
juxtaposition. Thus, in the first example, the reel
was modified into a colour inclining to violet, and the
orange was modified into gellow.
Colours used

in the experiment. M odificaiion.
1. Red inclining to violet.
Orange ................ .. ,, yellow.
2. Red ,, violet, or less yellow.
Yellow................... ,, green, or less red.
3. ,, yellow.
Blue ,, green.
4. ,, yellow.
Indigo.................... ,, blue.
5. Red ,, yellow.
Violet ,, indigo.
6. Orange ................ .. ,, red.
Yellow ,, bright green, or less red.
7. Orange ,, red,
Green.................... ,, blue,
8. Orange................... ,, yellow, or less brown.
Indigo ,, blue, or brighter indigo.
9. Orange.................. ,, yellow, or less brown,
Violet.................... ,, indigo.
10. Yellow................... ,, brilliant orange.
Green “nun-“Nu...” ,, blue,
11. Yellow................... ,, orange.
Blue ,, indigo.
12. Green.................... ,, yellow.
Blue ,, indigo.
13. Green.................... ,, yellow
Indigo ,, violet,
menu;
167
Colours used '-
Modification.
in the experiment.
14. Green ,, yellow.
Violet ,, red.
15. Blue ,, green.
Indigo ,, deep violet.
16. Blue ,, green.
Violet ,, red.
17. Indigo................... ,, blue.
Violet . ,, red.
The reciprocal modifications of colour are not
limited to the case where the modifying coloured
zones are contiguous to one another, for they may
be observed even when the zones are separated.
For example, take two stripes of the same Zrlue paper,
and two stripes of the same green paper, the blue and
green being of the same height of tone. Let the
stripes be a inches in length, and. gths of an inch
wide. Place them parallel to one another, so that the
two central stripes of blue and green are nearly ~5— of
an inch apart, and the two outer stripes of blue and
green each 41- of an inch from the two inner ones.
Then, standing at a distance of six paces from the
card, the colours will appear modified; the central
blue will be of a less green blue than the outer blue;
and the central green will be of a green more yellow
than the outer green.1
All the foregoing phenomena are expressed by
M. Chevreul in the following simple law :-—-“ When
the eye sees at the same time two colours which are
in contact, they will appear as dissimilar as possible.”
Hence the colour of the stripe 0, Fig. 1327, will differ
as much as possible from that of the stripe 1? when
the complementary colour of r is added to the colour
of o: in like manner the colour of P will differ in the
greatest possible degree from the colour of 0, when
the complementary colour of the latter is added to
the colour of r. Consequently, in order to know
what the two colours 0 and P will be when in juxta-
position, it will be sufiicient to find the complementary
colour of P, and add it to the colour 0, and the com-
plementary colour of o, and add it to 1?. For example,
take any one of the above seventeen cases, such as
the green and gellozo stripes, the result will be as
follows: red, the complementary colour to green, on
being added to gellozo makes it incline to orange ,- and
indzgo inclining to oz'olel, the complementary colour to
gellozo, makes green incline to clue. So also with red
and blue stripes; green, the complementary colour to
red, on being added to blue, makes it incline towards
green; and orange, the complementary colour to thee,
on being added to red, makes it incline towards
orange.
It will be evident, that, other things being the
same, the modification of the juxtaposed colours
will be more marked in proportion to the difference
between the complementary colours added to each:
for supposing that the complementary colour added


(1) The modifications referred to also take place when the colours
are at a considerable distance apart. Thus, we may take leaves of
coloured paper, twenty inches in length, and a foot in width,
instead of the bands used in the experiments; the two outer leaves
are to be placed one yard from the leaves in contact. By such
means, it is easy to produce the results to a large audience in a
lecture room.

to 0, Fig. 1327', be identical with ‘it, and that the
complementary colour added to P were identical with
it also, the modifications of o and 1? would be confined
to a mere augmentation in the intensity of the colour.
But we are not acquainted with two perfectly pure
colours complementary to each other. All reflected
rays of colour transmit not only white light, but also
variously coloured rays. It is therefore impossible to
name a red body and a green body, or an orange body
and a blue body, or a body of a gellozo inclining to
orange and an z'ndzgo coloured body, or lastly, a body
of a gellozo inclining to green and a mole! coloured
body, reflecting colours that are perfectly pure and
complementary to each other, so that their juxtaposi-
tion shall merely occasion a simple augmentation of
intensity in colour. If, therefore, it be less easy
in general to verify the law of contrast with respect
to red and green bodies, or orange coloured and Zrlue
bodies, &c., than with respect to those treated in the
seventeen observations already detailed,‘ it will be
found that in endeavouring to establish this law for
the first-named bodies, their colourswill acquire a
most remarkable splendour, vivacity, and purity;
because, by the law already stated, any object, say of
an orange colour, reflects blue rays just as an object of
a Mac colour reflects orange rays. So that when we
place a elue stripe in contact with one of an orange
colour, the colours of the two objects in juxtaposi-
tion will be mutually purified and rendered more
brilliant, whether this arise from the first-named
stripe imbibing elue from the vicinity of the second,
as that again receives orange from the vicinity of the
clue stripe; or whether we assume that the blue stripe
destroys the effect of the blue rays of the second
stripe, as that destroys the ‘effect of the orange rays
from the blue stripe. It may, however, happen that
the llue appears to incline to green or violet, and the
orange to gellozc or red; that is to say, that the modi-
fication is not limited to intensity of colour, but ex-
tends likewise to the physical composition. If the
latter effect he produced, it will be much more feeble
than the former; and in looking a certain number of
times at the same coloured stripes, the Mac, which at
first appeared more green, will soon appear more
violet‘; and the orange, which at first seemed to be
more gellozo, will soon appear to be more red, so that the
phenomenon of modification, which depends upon the
physical composition of the colour, ,will not be so
constant as those treated of in the seventeen observa-
tions.
White is also affected by the presence of colours.
If a coloured stripe be placed by the side of a while
one, the latter will appear slightly coloured by the
complementary colour of the coloured stripe. Thus,
with a red and a ecln'le stripe, green, the complementary
colour to red, blends with the allele, and the red
appears to be deeper and more brilliant.
Black and while, which may to a certain extent be
considered complementary to each other, become,
conformably to the law, more different from each
other than when seen separately, owing to the efi'ect
of the white light reflected by the black, being more
168
Lienr.
or less destroyed by the light of the white band.
By an analogous action, io/zite heightens the tone of
the colours with which it is brought in juxtaposition.
The phenomena presented by blaele, when exposed
to the influence of colours, seem to be owing to the
colour with which it is brought in contact acting
relatively to the eye, upon the Write light reflected
by the blacb surface, in the same manner as if it
were brought in juxtaposition with a white surface.
Hence, the blue/e should be tinged with the com-
plementary tone of the colour touching it; and as
the tinge which it assumes is not weakened by so
much iobite light, as in the case where the colour is
brought in contact with white, it must be so much
the more striking. On the other hand,‘ as io/iite
heightens the tone of colours brought in contact
with it, bloc/e, on the contrary, tends to make them
ligbter. The tone of black must depend, 1. upon
the colour added to it; for example, an orange—
colouretl reel, an orange-coloured gellozo, or a gelloiois/i
green, will brighten it; while inrligo, even if it does
not heighten the tone, will not reduce it. 2. Upon
the force or brilliancy of the colour in juxtaposition
with it ; thus bright colours, as orange and gelloio,
tend by their brilliancy to add force to blacle; while
sombre colours, such as blue and incligo, do not produce
a similar effect.
When real and blue/e stripes are made the subject
of experiment, green, the complementary colour to
reel, blends with blue/e, and makes it appear less
reolclisb, the reel becomes more brilliant, and has less
of an orange or brown tone of colour. With green
and blue/c stripes, real, the complementary colour to
green, blends with bla'c/c, rendering it more violet or
reelelisli. With intligo anal blade, the gellozo inclining
to orange, the complementary colour to incligo blends
with blue/c, and brightens it considerably; the ineligo
also becomes brighter.
When a great difl’erence is produced by the juxta-
position of two colours, it is rendered appreciable by
bringing the same colour successively in contact with
the various colours belonging to one group ; for
example, reel anal orange : on‘ placing a scarlet or a
crimson reel in contact with an orange, the reel will
acquire a purple, and the orange a gellozo tone of
colour. Reel anol violet.-—An'alogous results are ob-
tained in bringing a scarlet and crimson reel in contact
with violet; the latter will appear to be bluer, and
the reel more gellozo, or less purple.
The juxtaposition of coloured stripes shows how
difficult it is to fix the type of colours. For example :
1. On placing reel in contact with an orange-coloured
reel, the former appears purple, and the latter more
gelloio ,4 but on placing the first-named reel in contact
with a purple real, the latter becomes more blue, and
the former more yellow or orange, so that the same,
reel will be purple in one case, and orange in the
other. 2. On placing gellozo by the side of an orange-
c‘oloured gellozo, the former appears greenis/i, and the
latter ‘more reol: but on bringing‘ the first-named
yellow’ in contact with a greenish gellow, the latter
will appear greener, and the former more orange, so

that the same colour will in one case incline to green,
and in another to orange. 3. Place blue in contact
with greenisb- blue : the former will incline to violet,
and the latter will appear more gelloio. If the same
blue be brought in contact with a violet blue, the
former will incline to green, and the latter will appear
more real: so that the same blue will have a violet
tinge in one case, and a greenisb hue in the other.
Hence it appears, that the simple or primitive colours,
rell, gelloio, and blue,‘ insensibly pass by the effect of
juxtaposition into the condition of compound colours,
the same reel becoming purple or orange, the same
gelloio, orange, or green, and the same blue, green, 01'
violet.
Ohevreul applies the term simultaneous contrast to
the modification of colour and height of tone expe-
rienced by two differently coloured objects when seen
simultaneously; and the term successive contrast to
the phenomena observed when the eyes, after having
looked for a certain time at a coloured object, perceive
images of a colour complementary to that of the
object. The physiological explanation of the succes-
sive contrast of colours, is based upon the following
proposition by Scherffer, “that if a double impression,
of which one is vivid and strong, and the other weak,
be produced upon one of the senses, we shall perceive
the stronger of the two. This occurs principally
when both are of the same kind, or when the powerful
action of an object on one of the senses is followed
by another of the same nature, but infinitely weaker
or less violent.” To illustrate this, let us look for
some time at a small wbite square, placed upon a
blue/e ground. On ceasing to look at this, and tum-
ing the eye upon a blae/v ground, we perceive the
image of a square, equal in extent to the iobite square,
but instead of being ligbter than the ground, it will
be darker. ' The explanation is, that the part of the
retina on which the zobite light of the square acted
at the first part of the experiment, is more fatigued
than the remainder of the retina, which has only
received a faint impression from the faint rays re-
flected by the blac/c ground: the eye then being fixed
upon the blac/c ground during the latter part of the
experiment, the weak light of this ground acts more
strongly upon that part of the retina which is still
unexhausted, than upon that which has already been
fatigued 5 and hence arises the image of the black
square seen by that portion of the eye.
If we look for some time upon a small blue square
on a io/iite ground, and turning the» eye away from
the square fix it on the iobite ground, we see the
image of an orange square. ‘ The explanation is, that
the part of the retina on which the blue light of the
square has acted inthe first case, being more fatigued
by this colour than the rest of the retina, it happens
inthe latter part of the experiment, that the retina
which is fatigued by the blue, is consequently dis-'
posed to receive a stronger impression from orange,
the complementary colour of blue.
It appears, 'then, that ‘in cases of successive con-
trast, accidental colours arise from fatigue of the
eye; but Ohevreul does not admit this to applyto
LIGHT. '
i 1169
cases of simultaneous contrast ; for in arranging the
coloured stripes, as in Fig. 1327, as soon as we
succeed in seeing all four together, the colours may
be observed to be modified before the least fatigue
is experienced. by the "eye, although it frequently
requires several seconds before the modifications can
be perfectly recognised. But the time thus employed
appears to be as necessary as that which we give to
each of our senses,‘ whenever we wish to give an
exact account of the perception of - a sensation
affecting them. Time seems also to be required, on
accoiuit of the influence of white light, reflected by
the surface modified, .and which is sometimes strong
enough to weaken the result of the modification, and
it is only when the influence of this white light begins
to decline, that the accidental colours of simultaneous
contrast are favourably seen.
this cause that grey and blacl: surfaces, contiguous to
the surfaces of very bright light colours, as blue, real,
and guellouaare modified more than a white surface
would be by their vicinity.
M. Chevreul does not pretend to reduce to theory
the beautiful and important phenomena which he has
so skilfully and industriously brought together from
his own labours, and from the labours of others. He
wishes to express the general fact, “that when the
eye is struck at once by two colours, which it views
with some degree of attention, the analogous character
of these colours acts less powerfully upon the optic
nerve than the heterogeneous ; or in other words, the
eye evinces less sensibility in catching the analogies,
than the differences of the colours, and this without
our being able, generally speaking, to say that the
It is further owing toe

he has, at least, established 'a rule‘ or-law of ~ an emi~
nently practical character. .Wewill give a few of its
applications.
Suppose a painter to have delineated two stripes
in a picture, a reel stripe and a blue stripe in contact;
the phenomena of the contrast of two colours . in
juxtaposition would occur, unless the painter had
taken care to sustain the real contiguous to the blue
stripe by blue, and the blue stripe by placing real or
tablet near the reel stripe. A weaver having to
imitate the two stripes, ignorant of the law of the
contrast of colours, will select his wools or silks of
only one blue and one real, and thus bring about the
phenomena of contrast which the painter avoided by
an ingenious artifice. Or if the painter had not
blended the colours on their contiguous borders, they
would have contrasted. Now if the weaver, ignorant
of the law of this phenomenon, and attempting to
imitate his model, were to blend yellow or omuge
with the real, and yellow or green with the blue in the
parts of the stripes that came in contact, the con—
trast would be more or less exaggerated; because the
weaver attempted to imitate the effect of homo-
geneous colours produced by the picture, by Working
with homogeneous colours.
Let a paper, Fig. 1328, divided into 10 equal
zones, be first painted with a uniform tone of any
colour, as with Indian ink: let the zones 2 to 10
receive a second wash of the same uniform tone; let
the zones 3 to 10 receive a third, and so on until 10
zones be procured, which gradually increase in depth
of tone, proceeding from the first onward. The
remarkable part of the phenomenon is, that. each

organ is fatigued.” It is also
shown “ that two colours w 11
seen distinctly and simulta-
neously are mutually modi-
fied, independently of their
respective extent, even when
they are not in contact, and
when there is no ground for
attributing their modifica-
tions to a fatigue of the
eye.” a Z, a1 61
Some objections may per-
b1 b2
621
a2 b2

623 53

a4 b4 a5 b5 as b6 a7 b7 a8 b8 a9 b9
10
a6 b6 a7 b? as b8 a9 b9
65
a3 b3 a4 b‘? u6


haps be .made to the use of
the term simultaneous, on the ground that the distinct
vision of two separate colours is, in fact, successive;
for it is not possible to fix the eye steadily upon two
colours at the same instant; and when we fancy we
succeed in doing so, the eye is in fact passing rapidly
from one to the other; in which case, the modifica-
tions of colours by juxtaposition is a purely physiolo-i
gical eflect, and the theory of Scherffer will apply.
The effects on the mind are, however, the same as if
the contrasts were really simultaneous; and they are
now so well understood, that it is quite easy to de-
termine beforehand the exact effect which any given
combination of colours will produce. This is one of
the valuable results of the inquiry, and it is gratifying
to know, that if M. Chevreul has not succeeded in
framing a satisfactory theory of complementary colours,
. Fig. 1328.
zone will present at least two shades, owing to the
l contrast produced by contiguity; for instance, in
beginning from the first the border b b of this zone,
contiguous to the border u’ a’ of zone 2, will appear
lighter than the border are ,' and consequently two
shades will be presented in zone 1, and the same in
the others. But it is possible that a larger number
may be distinguished, especially in the intermediate
zones between 2 and 9, provided they are of sulficient
breadth, and this is owing to the borders a1 u1 a2 a2
being lighter, and the borders b1 b1 b2 b2 darker
than the general tone of the zone, when, by reason
of contrast, the middle of the zones, being less
affected than the borders, will present a third tone of
colour. It is evident that the three tones, or the

two tones as the case may be, presented by the zone,
170.
LIGHT~
will not terminate abruptly, but blend‘ into one
another. Now, if aweaverwere to copy this figure,
and were not acquainted with the effect of contrast
of contiguous zones, he would exaggerate the effect
in his work, using probably at least twenty shades of
the same colour, instead of the ten, -
“ I have frequently,” says hi. Ohevreul, “been
appealed to as an arbiter in cases where persons
having given to beprinted various woollen stufi’s for
furniture, and ladies’ cloaks, and have had disputes
with the printer on the subject of the patterns, which
were not of the colour intended. I have often found
that these complaints depended upon the effect ‘of
the contrast of the colour of the designs with that of
the ground, and that if the printer were reprehensible,
it was not for having printed a different colour from
the one required, but for not having foreseen the
effect that would result from the contrast of colours,
one of which was to serve as a ground for another.”
For example, when blue/{c patterns are printed upon
reel, crimson, or amarantli grounds, they appear green,
the complementary to the ground appearing on the
black. For the same reason, black when printed on
oiolct stuffs, or on elarl; green, loses all its force. In
order to prove that the designs which do not appear
black, are really black, all that is necessary is to cut
a piece of white paper so as to cover the ground, and
show only the pattern. Similar difliculties arise in
manufactories of paper-hangings, when it is required
to produce a design of a slightly gellowis/i greg upon
a green ground; the designs, although actually grey,
appear to be pinle, owingv to the complementary colour
of the ground. printed. on rose-coloured ground,
they appear green for the same reason. In printing
letters on coloured paper, the ground should always
be complementary to the colour of the ink. Thus a
violet-coloured ink must be used for yellow paper;
and gellow ink on a violet-coloured paper ; reel ink on
green paper, and green ink on reel paper; orange-
coloured ink on blue paper, and blue ink on orange-
coloured paper.
The upholsterer and house decorator, in the assort-
ment of stuffs with fancy woods for making sofas,
easy chairs, 850., must attend to the law of simul-
taneous contrast. Thus, violet or blue stufl’s should
be selected for gellow woods, such as orange wood,
the root- of‘ the ash, &c., and green or gcllow stuifs for
red Woods, like mahogany. The colour of the stuff '
must be as diflerent as possible from that of the
wood. A crimson stuff is one of the best wearing
colours, and hence it is often used with mahogany.
The bad effect of; this arrangement may be diminished
‘ by placing. abroad green, or blue/e border, a cord, or
sprinted hand, between the crimson and the maliogang. .
It is not uncommon to border crimson with a golel '
cord, or-band, fastened on with gold—headed nails;
and although these borders are not complementary,
the client; is brilliant. There is one combination which
ought never to. bemade, viz. gellowisb-reel as scarlet,
flame-coloured, or liglit reel stuffs with mahogany;
since their brightness deprives the wood of its
characteristic red colour, and makes it resemble oak;

or walnut. Decorative painters fall into the fault of
using. pintv or a light amarantb for the hangings of
boxes in a theatre, the eiiect of which is to give a
greenisli tinge to the complexion. In the choice of
patterns for dainasks, for furniture, opposition of the
grounds with the predominating colour of the designs
upon them, is too often disregarded. For instance,
where a wreath of flowers is to be represented on a
crimson ground, the greater part‘ ought to be com-
posed of blue, gellow, and wlzite flowers ; if reel flowers
are introduced, they should border 011 orange rather
than purple ,- while green leaves laid directly on the
ground condluce considerably to the beauty of the
whole; where the ground is green or eleael-leaf, the
predominatingv flowers ought on the contrary to be
pin]: and reel.
Not only may the pattern designer, whether for
figured stuffs, silks, carpets, &c. derive much assist—
ance from the study of these details, but also the
artist, the glass stainer, allthose, in short, who have
to deal with colour. Even the florist may enhance
the charms of his art by attention to the law of
simultaneous contrasts. “ Nothing is more common,”
says M. Ohevreul, “than a defect of proportion
observed in the manner in which flowers of the same
colour are made to recur in a garden. At one time
the eye sees nothing but blue or white, at another it‘
is dazzled by yellow scattered around in profusion:
the evil eflect of a predominating colour may be further
augmented, when the flowers are of approximating
but still different shades of colour. For instance, in
the spring we meet with the jonquil of a brilliant
yellow, side by side with the pale yellow of the
narcissus; in the autumn, the Indian pink may be‘
seen next to the China rose and the aster, and dahlias
of diii'erent red grouped together, 850.” “ The principal.
rule to be observed in the arrangement of flowers is
to place the blue next to the orange, and the violet
next to the yellow, whilst reel and pin/e flowers are
never seen to greater advantage than when surrounded
by oerelure and by w/iite flowers : the latter may also
be advantageously dispersed among groups formed of
blue and orange and of ‘violet and gellowflowers. For,
although a clump of white flowers may produce but
little efl’ect when-seen apart, it cannot be denied that
the same flowers must be; considered as indispensable
to the adornment of a garden when they are seen
suitably distributed amongst groups of- flowem, whose
colours have been assorted according to the law of
contrast. There are periods, of the horticultural
year, when white-flowers are not sufliciently abundant _
to enable us to deiivethe greatest possible advantage
from the flora of our gardens. It should be remarked
that plants whose flowers, are to produce. a contrast
should be of; the same size, and- that in many cases
the» colour of, the. sand or gravel composing the,
ground of- the walks-or beds of a garden may be made»
to conduce to. the. general effect.” ,
The. application of the law to the colours of dress,
requires $01116. notice. It is a matter of common,
‘observation, that a uniform composed of cloths of.
,difl’erent ‘colours looks well much longer, although;
LIGHT. ' l'fl
worn, than one of only a, single colour, even when the
cloth of the latter is identical with one of those com-
posing the former. The law of contrast perfectly
explains the reason: if we suppose a uniform to be
made of cloth. of two colours, the one complementary
of the other, as red and green, orange and blue, yellow
and violet, we shall find that the efiiect will be most
excellent from their mutually heightening one another;
and supposing, further, that they are of equal stability,
they will present greater advantages, and appear
good in spite of atmospheric agents, longer than any
other binary combination of colours. In a blue and
yellow uniform, the blue gives to the yellow an orange
tint, which greatly heightens its effect, notwithstand-
ing its tendency, as a dark colour, to make another
colour appear lighter ; the yellow imparts in its turn
a violet tinge to the blue, which considerably improves
its appearance, and if the blue had an unpleasant
greenish tinge, it would be neutralized by the yellow.
On the other hand, stains will always be less visible
on a dress of different colours than on one composed
only of a single colour, since there exists in general
a greater contrast among the various parts of the
first-named dress than between the stain and the
adjacent parts; this difference renders the efiect of
the stain less apparent to the eye. For the same
reason, a coat, waistcoat, and trowsers, of the same
colour can only be worn to advantage together when
all are new; for as soon as one of them‘ loses its
freshness from having been worn longer than the
others, the difference will increase by contrast. For
instance, a pair of new black trowsers, worn with a
waistcoat of the same colour, which is old and a
little rusty, will make the tinge of the latter appear
more conspicuous, at the same time that the black of
the trowsers will appear more brilliant. White or
even light grey trowsers would produce a contrary
effect. We see from this, how advantageous it is to
let soldiers have winter trowsers of a different colour
from that of the clothes which they wear during the
rest of the year; and we can further understand the
advantage there is in wearing white trowsers with a
blue, or indeed, generally speaking, with any dark
coloured coat.
The Great Exhibition afforded abundant evidence
of the superior taste of the foreign decorative artists
as compared with that of our own exhibitors. Where,
for example, the goods were each of a single lively
colour, variety was produced by means of figured
canopies and draperies: where, on the contrary, the
goods were of light materials, such as muslins, and
were covered with floral designs, plain-coloured cano-
pies and fittings, sometimes of rich materials, were i
1' much attention as the material, and the examples of
employed: in some cases the colours were concen-
trated and brought to a focus by the judicious intro-
duction 'of a well-assorted pile of plain merinos and
crapes of pure colours, the surfaces of which having
no lustre, are seen in their proper colours. In an
assortment of black silks the sombre effect of the
black was obviated by the introduction of a few
pieces of orange coloured silk. Even such articles as
feather brushes were coloured and arranged with

artistic skill. In some, the outside feathers were red,
and those in the centre yreea ,- in others, the outside
feathers were green, and the middle ones reel; in
others, Mae feathers harmonized with orange; and so
on. In the British department the combinations of
colour were often crude and unpleasant, and the con-
trasts positively painful; whereas, in the foreign
departments, harsh and inharmonious contrasts were
avoided, as Mrs. h/Ierrifield observes, by interposing
rich figured or striped goods of different, but friendly
colours, so as to conduct the eye agreeably and gra—
dually from one contrasting colour to the other.1
The lady just referred to has made some excellent
remarks on the various pattern designs as they came
under her notice in the Great Exhibition. We will
conclude this article with a few brief extracts.
noticing at some length the coloured patterns of the
carpets, she refers to those “libels on pictures exe-
cuted in Berlin wool,” and justly remarks that, “if
half the time that young-ladies devote to these use-
less labours were devoted to the acquirement of a
knowledge of the principles which govern the harmony
of colours,-—-a kind of knowledge which is very easily
attained,-—-the good effects would soon be apparent,
not only in the more appropriate choice of subjects
on which to display their skill in needlework, but-in
better and more tasteful work applicable to domestic
purposes.” The proper subjects for this kind of work
are flowers, birds, arabesques, and other objects
which admit of the introduction of lively colours.
Subjects which involve the combination of tints,
requiring nice gradations of .colour and a careful
attention to light and shade, such as occur in figure-
subjects, should be avoided.
The papz'er-meie/le’ and japanned goods presented but
few examples of good taste in colouring. “ In these,
the glitter of metallic colours is too frequently mis-
taken for richness, and violent contrasts for harmony.
The artist seems to run riot in the riches of his
palette, and to endeavour to dazzle if he fails to
please. In. speaking of the want of harmony in the
colouring of carpets, due allowance has been made for
mechanical defects, which'render the adoption of cer-
tain designs a matter of some difficulty; but none of
these defects can be imputed to the painting of pap-zen
mic/re’. works. 'With an almost unlimited ‘scale of
colour, and obedient materials, which are capable of
producing the richest and most harmonious eEects of
colour, these works, by the bad taste too often per
ceptible in their decorations, contrast disadvantage-
ously with the Indian articles of the same nature, in
imitation of which they were originally manufactured.
“ The Indian principle of ornamentation deserves as
the tiles and mosaic pavements may be adduced as
instances of the advantage attending the study of the
principle of decoration adopted in national manufac-
tures, as well as the materials employed. The same
abruptness and crudity of colouring which are per-

(1) “ Essay on the Harmony of Colours as exemplified in the
Exhibition.” This Essay has already been referred to in 0111’ Intro-
ductory Essay, p. xlviii.
After '
1'72
LIGHTHOUSE.
ceptible in the English carpets,eare also, too-often
visible in the printed table-covers, the dyed sheep~
skins, the designs for . silk handkerchiefs, and the
furniture chintzes and damasks. In many of the latter
the designs are very beautiful, but the colours are
frequently ill-assorted, as well as harsh, from the ex-
treme strengt/i, and in some cases blackness, of the
shadow colour, especially when contrasted, as fre-
quently happens with regard to furniture-prints, with
a white ground. Although, as has been justly re-
marked, the British manufacturers are inferior in
colouring, and frequently in design, to the continental
exhibitors in decorative art—for under this term we
must include those elaborately ornamented carpets,
dress, and furniture fabrics, exhibited in the Crystal
Palace—there is evidently an improvement upon
former designs; and when the subject of colour has
received the attention which it deserves, we may
confidently reckon on a still greater improvement.
The elegant designs, and the harmonious colouring of
the French and Italians in their art-manufactures, has
been the subject of general commendation; but neither
of these nations acquired their good taste in design
and colour in a day, or without study. In former
times, it is well known, the best Italian artists did
not think vit beneath them to make designs for art-
manufactures; hence the good taste of the Italians in
the lower branches of art. The French have had
schools of design for more than a century; and in
consequence of the attention paid in these schools to
the harmony of colours, their art-manufactures exhi-
bit a better and more harmonious style of colouring
than many of their works of the higher classes of
art,-—a convincing proof of the success attending the
study of the subject, and the advantages to be de-
rived from the contemplation of good examples.
When the British manufacturers study colour with
the same earnestness as the British artists have done,
the happy results will be visible in their productions;
. and not until then can they successfully compete in
the decorative arts with their continental neigh-
hours.”
LIGHTHOUSE. An elevated structure erected
on a rocky or dangerous shore, for the purpose of
raising to a conspicuous height the warning beacon
which shall repel the mariner, and enable him to
avoid destruction. The erection of a lighthouse or
beacon is an evident duty of common humanity, and
it appears to have suggested itself as such among the
nations of antiquity. Beacon fires were kindled at
< an early period» along the most frequented coasts,
flaming forth perhaps from the summit of a temple‘
dedicated to the gods, and where sacrifices were
being .ofiered to appease the genius of the storm.
There are few distinct early evidences of the erection
- of lighthouses as such, although there are allusions
to the subject of beacon lights for the guidance of
the mariner. in the writings of Homer and others.
But it is ..a matter of certainty that in the reign of
Ptolemy Philadelphus, about 300 years before the
Christian era, there was erected at Alexandria the
celebrated Pharos, or beacon tower, which ranked

among the ancients as one of the seven wonders of
the world. Sostratus, the architect, is recorded to
have built this structure in a wonderful manner, of
many storeys of white stone on a rock, forming the
promontory of the island of Pharos, and to have
dedicated it “ to the gods, the saviours, for the
benefit of seamen.” Pliny says that this tower cost
a sum equal to about 390,000l. The different de-
scriptions of. this celebrated lighthouse leave it a
matter of uncertainty whether the beacon displayed
the flickering and rude light of a common fire, or
whether a more perfect mode of illumination was
employed. It is stated to have been 4100 feet high,
and to have sent its light to a, distance of 410 miles,
both of which are manifest exaggerations. Con-
temporary with the erection of the Pharos of. Alex-
andria was that of the Colossus of Rhodes, by many
supposed to have been the bearer of. an important
beacon-fire. This gigantic statue of brass, between
whose legs vessels could sail into the harbour which
it spanned, was partly demolished by an earthquake
seventy years after it was formed, and so late as the
year 672 of our era 5 the brass which composed it was
sold to a Jewish merchant of Edessa, by the ‘Saracens,
who received for it a sum said to equal 36,000l.
The traditionary history of Ireland makes mention
of the Tower of Coruiia, as a lighthouse erected for
the use of the Irish in their early intercourse with
Spain. Other ancient lights are spoken of, but our
knowledge of them is neither accurate nor extensive.
Many of them appear to have been merely pots of
fire raised on poles, or placed on the summit of rocks,
the greater number being described as existing on
the shores of the Mediterranean Sea.
Among modern lighthouses, the earliest having any
pretensions to architectural elegance is the Tour de
Corduan, at the mouth of the Garonne. This is 197
feet high, and consists of a number of galleries, sur-
mounting an immense platform of solid masonry. The
galleries gradually diminish in diameter, and termi-
nate in a conical tower, and lantern. In the latter
a wood fire first formed the beacon, then a coal fire,
and at last lamps and reflectors. The celebrated
apparatus of Fresnel was adjusted in this lighthouse
in 1822.
The history of the lighthouses successively built on
the Eddystone rocks is full of interest, but can be
only glanced at here. Those rocks are situated M
miles from the port of Plymouth,_,and 9% ‘miles from
a point. of vlandcalled Ram-Head, ‘on-wthe coast of
Cornwall. Many rich vessels were formerly lost on
these dangerous, rocks, which lie ‘ exposed to the
heavy seas from the south-western points of the com-
pass, and from. ‘their peculiar conformation increase
the swell to. a frightful extent, often sending up the
waves to a height of thirty or forty feet. The whole
range-of these rocks is covered by the tide at high
Wat-613 50.131131? ‘6116 difficulty of commencing and carry-
ing onv the; structure between the tides was immense.
It was‘ first attempted by Henry Whistanley, who
after. £0111‘ X69118’ 18130111‘, Working only in the summer
season, CODStI‘IIOiJBd a lighthouse of timber. This
LIGHTHOU SE.
173
work was commenced in 1696,--it'had advanced suf~
ficiently to exhibit alight in‘1698, but it was not
completed till 17 00. The instability of the structure
was unhappily proved, three years later, by the de-
struction of the lighthouse with its engineer and _
workmen, engaged there on repairs during a violent
storm, 26th November, 1703. Another lighthouse
was‘ commenced in 17 06, by John Rudyerd,—~the light
was shown ‘in 1708, and it continued to be displayed
for A7 years, when the lighthouse was accidentally
destroyed by fire. This second edifice was also of
timber, but remarkably well constructed and simple
in form, 92 feet high and 23 feet diameter at the
base. The foundation was of oak-timber and stone,
in alternate layers, secured with cramps of iron, the
whole being fastened with bolts or branches of iron
to the rock.
The value—of a light on the Eddystone rocks had
been by this time fully proved, and no time was lost
in endeavouring to supply the place of Rudyerd’s
structure. Happily the work was entrusted to John
Smeaton, whose name is now identified with the
undertaking, the more emphatically, because of his
own elaborate and interesting narrative of the whole
proceeding. The first stone was laid June 12, 1757,
and the last August 24th, 1759. This beautiful
structure is entirely of stone, and the foundation
is most ingeniously secured ‘by a system of dove-
tailing, cementing, weclging, and bolting together
with stone joggles and oaken trenails, which con-
nects, and makes it one with the natural rock, the
sloping surface of which had been cut into steps or
terraces to receive the foundation stones. Fig. 1329
is a plan of the bouse-roc/c, or that on which the house
was built, as prepared for the stone work. The first
course is seen occupying the lowest step, and secured
with its trenails and wedges: it is laid within a bor-
der of solid rock, and is held fast in every direction.

Fig. 1329. PLAN or THE HOUSE-ROCK, as PREPARED BY SMEATON.
The figures 1, 2, 3, 4, 5, 6, mark the level steps or
platforms into which the rock was cut for the dif-
ferent courses. Fig.1330 shows the appearance of
the rock when these platforms had been filled with
their respective courses, and the whole work brought

to a level with the reduced rock. When this was
effected, and means no longer existed of securing the
stones to the rock, Smeaton devised the expedient of
bolting the courses together, by cutting a hole a foot


Fig. 1330. THE nocx BROUGHT To A LEVEL.
square through the centre stone of each course, and
fitting into it a plug of strong hard marble, which
should be long enough to enter a similar hole in the
centre stone of the next course. These centre stones
were dove-tailed into the surrounding stones, and no
force of the sea acting horizontally could afiect the
masses thus secured together. Besides the central
plug-juggle (as Smeaton calls it), there were eight
other joggle or plug-holes in the circumference, not
only in that part occupied by the stone course, but
also in the solid rock. The courses thus laid and
ingeniously secured formed the whole of the founda-
tion work: this was severely tried during the time
of its erection, and also in the winter following, but
stood the utmost force of the waves, and became
like the solid rock itself. The building was next
carried up in a solid form, as high as there was any
reason to expect the heaviest strokes of the sea to
act upon it, namely to 35 feet éh inches above the
base. At this height the rooms were commenced,
the walls of which were made of
single blocks of stone, so shaped
that sixteen blocks formed a com-
plete circle, or stout wall 26 inches
thick. Fig. 1331 shows a part
of the wall thus constructed: f is
a marble plug the size of a com-
mon brick, let half its thickness
into the middle of the stone, so
that the next course above, break-
ing joint upon the middle of this,
according to the dotted line 51g,
half the plug would enter the one
and half thev other of the two
stones which met above it. Thus
every stone of the succeeding course was secured
between steady pins at each end. The black lines it 2‘
mark the joints of the course, in the centre of which is
a lozenge-shaped groove filled with a joint stone, over

Fig. 1331.
174;‘
LIGHTHOUSE.
which, for greater security, was fitted an iron cramp, 3
the shape of which is shown at m a : '0 p marks appearance as fitted in its place. vHoles ‘were bored;
in the stone at g r to receive the round-shanks of the cramp, and rectangular cavities sunk to buy the flat?
part of the cramp. The mode of inserting these
cramps was to make each cramp hot, then to place it
in the holes, which 'hadviprevi'ously' bade spoonful of
oil poured into each. "Theiebullitioii of the oil made
the whole cavity mien-ions, and assisted‘the perfect
filling up “of __ every crevice ‘with the Yniolt'en lead,
which wasneit poured the cramp was com-
pletely covered. The courses ‘on which the floors of
the rooms rested were further strengthened by having
a groove cut ‘in their upper surface, and ‘a chain intro-
duced as shown at
Fig. 1332 : the groove
was then filled up
with melted lead;
~ Fig. 1332. thus the building was
hooped or girdled together at the parts where danger
might have arisen from lateral pressure. In this
way the walls were carried up, forming first the
low er and the upper store-room, above them the
kitchen, and ‘then vthe bedroom, above which rose the
lantern with its railed balcony, cupola, and gilt ball.
This noble structure was commenced on the 12th
June, 1757, and completed on the 24th August,
1759.1 The main column of the lighthouse contains


forty-six courses of stone, and reaches the height of
nearly 70 feet. _ The diameter at the level of the first
entire course is 26 feet : the diameter under the
balcony is 16 feet. In addition to the windows for
the lantern, 10 other windows exist in the edifice,
41 each in the kitchen and bedroom, and '2 in the
store-room, but these are small, and capable of being
entirely closed and made level with the outer wall of
the building, by means of storm-shutters.
The completion of the Eddystone lighthouse was fol-'
lowed by a series of storms which efiectually tried the
strength of the building, and also produced the greatest
terror in the minds of the first light-keepers. Smeaton
watched the edifice with the greatest pleasure and
interest, and when .viewing it with his telescope from
the garrison at Plymouth, after a great storm, he
found to his astonishment that at intervals of a
minute, and sometimes two or three, when a combi-
nation happened to produce an overgrown wave, “it
would strike the rock and the building ,conjointly,
and fly up in a white column, enwrapping it like a
sheet, rising at least to double the height of the
house, and totally intercepting it from sight; and
this'appearanee being momentary both as to its rising
and falling, one was enabled to judge of the com-
parative height very nearly, by the comparative spaces

(1) Smeaton’s account of this noble work was not published
until ‘the leisure consequent on his retirement from the duties of
a useful and laborious life enabled him to collect and prepare the
materials required. In 1791'he published a folio volume, entitled,
“A Narrative of the Building and a. Description of the Con-
struction of the Edystone Lighthouse‘with stone: to which is
subjoined an Appendix, giving some account of the Lighthouse
oiithe‘ Spurn ‘Point, built 'uponi'a sand.”

‘alternately occupied by the house and the column of
water in the field of the telescope.” After the occur-
rence of many such storms without the least injury
_to the building, the safety of the Eddystone was
never doubted, and light-keepers even became at-
tached to the spot vand reluctant to leave it. In fact
it was ‘a much safer place during violent gales than
most parts of the neighbouring shore. The lights
first displayed were merely tallow candles: Argand
burners, and paraboloidal reflectors were substituted
in 1807.
The lighthouseson the coast of Scotland are de-
servedly celebrated. Systematic efforts for lighting
this extensive and dangerous coast were not com-
menced until 1786, namely, twenty-‘seven years after
the completion of‘ the Eddystone. Four lighthouses
were all that had been at first contemplated ; but when
these were erected, one on Kinnaird Head in Aberdeen-
shire, one on the Orkney Islands, one on the Harris
Isles, and one at the Mull of Kint'yre in Argyleshire,
their importance to navigation became so evident, that
great efforts were made on the part of the shipping
interest to obtain others. In the course of time, light-
houses, or the means of exhibiting lights, were erected
upon many promontories of the main land, as well as
upon islands and reefs lying off thecoast of Scotland,
including the Isle of Man.
The most celebrated of the Scottish lighthouses,
and that which may be taken as the representative of
‘the whole, is that on the Bell Rock, a dangerous reef
at the entrance of the Frith' of Forth, also known as
the Inch Cape Rock, and as such celebrated in
Southey’s ballad of “ Sir Ralph the Rover.” This
reef is frequently under water to the depth of from
twelve to ‘fifteen feet, therefore the erection of a
lighthouse was a work of peculiar difiieulty. Robert
Stevenson, however, examined the rock, and reported
'that it was practicable, and that *a'work of stone similar
to that of the Eddystone might be erected there. The
Bell Rock is twelve miles ‘from the shore, and lies
directly in the fair ‘way to the ll‘riths of Forth and
Tay ; meter-ere ~it is most dangerously situated for
vessels, and has in fact been a most ‘fatal reef, de-
stroying many a noble ship and valuable freight.
The first step towards ‘Stevenson’s great work, was
to moor a fishing ‘vessel “(iii the Bell Rock,~-at the
distance of about two miles, serve the. idbuble
purpose of a floating light, andatendeiiifor theiiii‘r‘erk-
men‘ie’iirpleyed in the 'i'ii‘és's'el was rigged
with three irii‘ais‘tsf’on eaeli *lanterrr‘was
hoisted 5‘ Ts'lije was ‘also ‘crew consisting
of a master, eight seamen, aiitla‘bioy.
The first act-“a ‘war on the rockliebii’sisted in
boring a sufficient number of holes 2‘to receive the
ends of beams for the ‘suppeit "of a wooden beacon or
workshop, and ‘temporary residence for the workmen.
This was a most difficult operation, for in addition to
the hardness of the rock, which blunted the tools and
required the‘eonstant help of a smith with his forge,
there was the precarious nature of the work, owing to
"the short time the men could be on the rock, and
even then frequently knee-deep in water. The rowing
LIGHTHOUSE.
1'75
backwards and ‘forwards from the floating light at
every tide was found very laborious, and when the
sea was rough it was impossible to leave the moored
vessel, the putting out of a boat being almost certain
destruction. The temporary building of timber being
finished, and an extensive excavation made, at im-
mense labour, in that part of the rock designed as the
site of the permanent structure, the nature of the
subsequent daily operations was as follows :—-The
workmen landed on the rock at low water, and imme-
diately began to bale out the water from the founda-
tion pit, while the pumps were also kept in action.
The work was proceeded with on the higher parts of
the foundation as the water left them. The pumps
being placed diagonally, about twenty men were em-
ployed to work each pump; and thus this great body
of water, extending over a circular area of 42 feet
diameter, and of the average depth of 2 feet, could
be drawn off in half an hour. The men then pro-
ceeded for two hours and a half to level the founda-
‘tion with their picks, some of the sailors being
employed to clear away the chips, and convey the
iron tools to and from the smith’s forges, which were
flaming on the temporary building above, while the
anvils thundered with the rebounding noise of their
wooden supports. The tools were thus continually
sharpened, and the work was carried on with urgent
speed, until the sea again broke in and overflowed
the pit, when the party returned in boats to the
tender. The perils and narrow escapes of this little
band of determined men are described in a highly
interesting manner by Mr. Stevenson in ‘his account
of this undertaking, published at the expense of the
Lighthouse Board in 1824:.1
The foundation stone of the tower was laid on
the 10th July, 1808, at the depth of 16 feet below
the high water of spring tides. It was square in
form, and contained about 20 cubic feet. The first
continuous course was then landed on the rock and
laid down. The kind and quantity of work in this
one course alone are thus enumerated by Mr. Steven-
son :—The course was only one foot in thickness, yet
it contained 508 cubic feet of granite in outward
casing; 876 cubic feet of Mylnefield stone in the
hearting; 104. tons of solid contents; 132 superficial
feet of hewing in the face work ; 4,519 superficial feet
of hewing in the beds, joints, and joggles; 420 lineal
feet boring of trenail holes; 37 8 feet lineal cutting
for wedges; 246 oaken trenails; 3'78 oak wedges
in pairs. Three seasons ‘were occupied in preparing
the rock, in laying the foundation, and carrying up
the solid part to the height of 30 feet. So short was
the time actually obtained for labour on the rock,
that 265 hours was the total amount during the
second‘ season, and of these only 80 were em-
ployed in actual building work. The winter months
of each season were, however, diligently employed on

(1) “An Account of the Bell Rock Lighthouse, including the
details of the erection and peculiar structure of that edifice. T 0
which is prefixed a Historical View of the Institution and Progress
of the Northern Lighthouses. Drawn up by desire of the Com-
missioners of the Northern Lighthouses, by Robert Stevenson,
4:0. Edinburgh, 1824. -

shore, in preparing the stones and accurately fitting
them, so as to shorten as much as possible the labour
on the rock. At the commencement of the next
season the workmen took permanent possession of
the rock, and the work proceeded rapidly. As the
tower rose in height the action of the sea upon it was
regarded with much interest. In a heavy surf the
effect was grand and magnificent, but not calculated
to excite alarm. In the early part of July 1810,
great interest was created by a visit of Smeaton’s
daughter to the rock. The building was then nearly
finished, and she came to view it in a boat which Mr.
Stevenson had named the “ Smeaton” in honour of
her father. The 29th day of the same month was
one of great rejoicing on the rock, for then the last
stone was landed. It was laid in its place on the
next day by Mr. Stevenson with the following
prayer,—“ May the Great Architect of the Universe,
under whose blessing this perilous work has pro-
spered, preserve it as a guide to the mariner !”
The remaining arrangements and interior details
were so far completed during the year that the light
was advertised to the public to be exhibited every
night from 1st of February, 1811. The adver-
tisement minutely described the nature of the light,
stating, “The light will be from oil, with reflectors
placed at the height of about 108 feet above the
medium level of the sea. To distinguish this light
from others on the coast, it made to revolve hori-
zontally, and to exhibit a bright light of the natural
appearance, and a red-coloiu'ed light alternately, both
respectively attaining their greatest strength, or most
luminous effect, in the space of every 41 minutes;
during that period the bright light will, to a distant
observer, appear like a star of the first magnitude,
which after attaining its full strength is gradually
eclipsed to total'darkness, and is succeeded by the
red-coloured light, which in like manner increases to
full strength, and again diminishes and disappears. -
The coloured light, however, being less powerful,
may not be seen for a time after the bright light is
observed. During the continuance of foggy weather
and showers of snow, a bell will be tolled by ma-
chinery night and day, at intervals of half a minute.”
The Bell Rock Lighthouse was now complete, and
its appearance was noble and pleasing to the eye.
(See Vignette to vol. i. of this work.) The form ‘is
circular, the tower is 100 feet high, and the whole
structure, including the light-room, is 115 feet. The
form of the light-room is octagonal, 12 feet across,
and 15 feet high. It is framed with cast iron and
glazed with plate glass-i A dome rises above it ter—
minating in a ball. The diameter of the tower at the
base is 42 feet, at the top 13 feet. The entrance
door is 30 feet from the base, and the ascent to it is
by a trap ladder. Visitors are generally hoisted up
in a chair by a movable crane. The cost of the erec-
tion of the Bell Rock Lighthouse was 61,3311. 9s. 263.
Another work of great labour and difliculty was
the erection of a lighthouse of stone on the Skerry-
vore Rocks, which lie about twelve miles WSW. of
the seaward point of the Isle of Tyree, in Argyll-
176
LIGHTHOUSE.
shire, and were formerly the scene of numerous fatal
shipwrecks. The operations were commenced in 1838,
the architect being Alan Stevenson, son of Robert
Stevenson, and engineer to the Board of Northern
Lighthouses. The difficulties, dangers, and successful
issue of this important undertaking, are described by
the engineer himself?
The construction of the lighthouse itself had no
very remarkable points of difference from the works
of Smeaton and-the elder Stevenson; we shall there—
fore only borrow-from this narrative a sketch of a
temporary ba'rrack, which formed the dwelling of the
engineer and workmen on the rock, during the pro-
gress of the permanent structure. Fig. 1333 will give
a good idea of the nature of this singular dwelling.



e if, !
mm ‘m -
mfl'imfillifill Wall-mil Illll
mm mlllfilll lllll
m 9:! ' Fill ,





k,
W a!
"' w‘ ll
\J\~/ tI
TEMPORARY BAR-RACK USED IN THE ERECTION OF
THE SKERRYVORE LIGHTHOUSE-
]. Store for Goals.
2. Kitchen and provision store.
3. Engineer's and foreman’s apartments.
4. Barrack room for workmen.
5. Ventilating lantern.
/
l"
u I n u.“ \ —-
' _-‘~-=1¢---_-~‘a-_.-
‘ .
If/J
Fig 1333.
n I
| l! ll
"H
l
“Immediately under the wooden tower,” says Mr.
Stevenson, “was an open gallery, the floor of which
was removed at the end of each season, so as to
allow free space for the passage of the sea during the
storms of winter, but on which, during summer, we

(1') “ Account of the Skerryvore Lighthouse, with Notes on the
Illuminatio‘n'of Lighthouses.” By Alan Stevenson, 8zc., Engineer
to the Northern Lighthouse Board. 4to. Edinburgh, 1848. The
Editor has to express hisv obligations to Mr. Stevenson for the
liberal manner in which he has allowed him to make use of this
work ‘in the preparation of this article.

kept the stock of coals, the tool chests, the beef and
beer casks, and other smaller materials which we
could not, even at that season, safely leave on the
rock itself. Next came the kitchen and provision
store, a six-sided apartment about 12 feet in diameter,
and somewhat more than 7 feet high, in which small
' space, curtailed as it was by the seven beams which
passed through it, stood a caboose, capable of cooking
for forty men, and various cupboards and lockers
lined with tin, for ‘holding the biscuits, meal, flour,
barley, and other things needful for the sustenance of
the human wframe. That apartment, for protection
against fire, was coated partly with tin, and partly
with sheet lead, which latter, although not in all
respects the most desirable material to come in con-
tact with that element, was found to be the only one
which we could in some parts conveniently apply.”
The next storey was divided into two apartments,
which together consisted of a twelve-sided narrow
space, twisted around a centre pyramid whose be-
velled faces formed their sloping walls on one side.
“ The half of that space,” says Mr. Stevenson, “ con-
stituted my apartment, which I think would be gene—
rally pronounced not over commodious; and when it
is ‘added that it contained my bed, desk, chair and
table,‘ and a stock of groceries, it will be readily
imagined I had little room to spare for myself. So
much ‘attention was paid to economy of space, that
the recesses of the pyramid formed by the meeting of
the beams were boarded over and made into cup-
boards; while my cot, or framed hammock (which
during the night rested upon brackets which could
be folded close to the wall when not required) was,
during the day, hoisted by pulleys to the roof of the
apartment, so as to leave me as much space to move
about as a prisoner could expect. The cornice of the
apartment consisted of a narrow shelf adorned with
books, which I found very needful helps to solitary
life. The highest apartment was also twelve-sided,
surmounted by a pyramidal roof, and a small six-sided
lantern or ventilator, and was lined round the sides
with four tiers of berths, capable of accommodating
thirty people.” -~
The instances already given will be sufficient to
show the nature of the operations carried on, when
a lighthouse is to be built upon the solid rock; but
there is another class of difliculties to be encountered
when a lighthouse is to be built upon the sand. This
was once thought to be impossible, so that floating
lights, or lanterns suspended in the;rigging of a
vessel, were the only means available in such situa-
tions. These were very imperfect, the lights being
liable to be hidden by the mist and spray, and the
tossing of the vessel, or the ship itself to be blown
away from its moorings during violent gales. It is
one of the. great triumphs of modern engineering,
that a permanent. residence can now be safely erected
on the vsand. Thisis effected by the aid of Mitchell’s
screwsmo'oring, which is’ an instrument consisting of
an‘ enormous cast-iron screw s, Fig. 13344, of about
one turnand a half, having a hollow cylindrical centre:
a wrought-iron spindle s’ passes through the cylindri-
LIGHTHOUSE.
1'77
cal socket, and is fixed . thereto by a forelock passing
through both; it is formed with a square head it, to
receive the, key for screwing it into the ground ; also
with a collar 0 of wrought-iron, fitted so as to turn
freely on the upper. part of the shaft of the spindle,
below the collar. The first experiment made with


Fig. 1334.
this instrument, with aview to its adaptation to light-
houses, was on the verge of the Maplin Sand, at the
mouth of the Thames. Nine of the mooring-screws
were inserted into the sands, one serving as a centre
to the remainder, which occupied the angles of an
octagon t2 feet in diameter. The screws were turned
into the sands to the depth of 215 feet, the upper
extremity being left standing about 5 feet above the
surface of the sands. A raft of timber was floated over
the spot with a capstan in the centre, fitted on the
top of an iron shaft, and firmly keyed to it. Thirty
men working at the capstan drove the screws firmly
into the sand, after which the heavy raft was allowed
to remain, and was sunk into the sand by means of
about 200 tons of rough stone. The whole mass soon
became embedded, and after remaining in that state
for about two years, the screw-piles also standing
firmly, a lighthouse was erected, and a dioptric fixed
light exhibited on this dangerous spot, 16th of Feb-
ruary, 1841. This was not, however, the first screw-pile
lighthouse actually erected, for during the long prepara-
tory process which was carried on at the Maplin Sands,
a structure on the same principle had been begun
and completed at Port Fleetwood, on the Wyre, near
Lancaster. The preparatory steps were similar to those
already described. The foundation of this lighthouse
was formed of seven screw-piles, six of them occupy-
ing the angles of a hexagon 46 feet in diameter, the
seventh being in the centre. From each screw pro-
ceeds a pile 15 feet in length, having at the upper
end another screw for securing a wooden column.
These columns are of Baltic timber, the one in the
centre being 56 feet, the others 46 feet in length,
firmly secured with iron hoops, and coated with
pitch. The platform upon which the house stands is
27 feet in diameter, the house itself being 20 feet
diameter, and 9 feet high. From the summit of the
house rises a twelve-sided lantern, 10 feet diameter,
and 8 feet high. Altogether, the light is elevated
about 416 feet above low water level, and ranges over
an horizon of 8 miles. The light is of the dioptric
kind, bright, steady, and uniform, and when the
weather is too foggy to allow it to be seen, a bell is
tolled by machinery, to give the needful warning.
This useful buildingwas ‘erected in two months, and
von. II.

those the shortest of the year, so that a great part
of the work was done by torchlight or moonlight.
,.




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‘My.’ fr. I
l‘ '1' ' ‘l
l. page i
l.
l. i
a ~‘-
"aim!


iiiiiililii ll

aliiizzgmr‘fii
is" Q"*" mars‘;












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giirls/










aw. 4;’, /,,;., a M7 I
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‘ -— V- ‘ ~___.__
— " "'-~‘,==:=~.~_——
p9,,=_-1r=~33;,,==——___.~.-_

Fig. 1335. scnEw-MLE LIGHTHOUSE nnEcrEn AT PORT FLEET-
woon, on THE WYRE, NEAR LANCASTER.
A. Formation of marl into which the screws are driven to the
depth of ten feet below low-water mark.
B. substratum of sand.
C. Low water, equinoctial springs. l
D. Low water, ordinary tides, 2 feet above 0.’
E. ditto neap tides, 9 ,,
F. Half tide level, 15 ,,
G. High water neaps, 21 _ ,,
H. ditto ordinary tides, 28 ,,
I. ditto equinoctial springs, 30 ,,
K. Underside 01‘ Platform, ,,
45
Centre of the _dioptric light 60
lantern,
At the time that screw-pile lighthouses were being
thus successfully erected, other and most valuable
suggestions were being made for the building of
bronze and cast-iron lighthouses. The great advan-
tages of iron over stone and other materials, in those
portions of the building not actually in contact with
sea-water, soon became apparent. Upon a given
base, a much larger internal capacity could be ob-
tained; plates could be cast in large surfaces, and
with few joints; and a system of bonding adopted,
which should ensure the perfect combination of every
part. The comparatively small bulk and weight also
of the component parts, gave great facilities for the
transport and rapid erection of such structures.
The first cast-iron lighthouse was designed by
Mr. Gordon in 1840, and was cast, and put together
n
H
178
LIGHTHOUSE.
within three months from the date of the contract.
It was then taken to pieces, and shipped for Jamaica,
on which island it now lights up a dangerous point,
called Morant Point. The commissioners of the
House of Assembly had applied to Mr. Gordon, to
supply a suitable lighthouse at the smallest possible
cost; and in furnishing them with this structure of
cast—iron, he fulfilled their wishes admirably, the ex-
pense not exceeding one-third of the cost of a similar
building instone. This elegant lighthouse, the out-
line of which resembled that of the Celtic Towers of
Ireland, was visited by the writer ‘while it stood
complete in the contractor’s premises. The diameter
of the tower is 18 feet 6 inches at the base, diminish-
ing to 11 feet under the cap. The tower is formed
of nine tiers of iron plates, each tier being 10 feet
high, and about ~2- inch thick. At the base of the
structure 11 plates are required to form the circum-
ference, at the top 9 plates; they are cast with a
flange around their inner edges, and when put together
these flanges form the joints, which are fastened
together with nut and screw bolts, and caulked with
iron cement. The interior of the tower to the height
of 27 feet, was to be filled up with masonry and
concrete of the weight of 300 tons ; the remainder is
divided into store rooms and berths for the attendants.
The tower is finished by an iron railing, within which
rises the light-room, also of cast~iron, with windows
of plate glass. A copper roof, and a short lightning
rod, complete the whole. The Admiralty notice
announced the exhibition of this light on Morant
Point, November 1, 1M2, and stated that the eleva-
tion of the light is 96 feet above the level of the sea,
and that in clear weather it is visible at a distance of
21 miles. The light is of the revolving kind, con-
sisting of‘ 15 Argand lamps and reflectors, five in
each side of an equilateral triangle, and so placed as
to produce a continuous light, but with periodical
flashes. The tower is painted white, and the lower
portion is coated with coal-tar to preserve it from
rust. It rests on a granite base, and is also cased
with granite near the foundation, the more certainly
to prevent the action of the sea-water on the metal.
It will be seen from the foregoing details that while
the engineer had attained some of his greatest triumphs
in the construction of lighthouses, the optician had
not once directed his attention to the invention of a
brilliant light, worthy to be placed upon the structure
which proudly rose high above the fierce waves, with
the strength and solidity of a rock. During a period
of‘ forty years after the completion of the Eddystone
tower by Smeaton, the lantern was illuminated by
tallow candles stuck in hoops, just as a show-booth is
lighted at a country fair, and so lately as the year
1811 it was lighted with 24L wax candles. In 1812,
the Lizard light was maintained with coal fires ; and
in 1816, when the Isle of May light, in the Frith of
Forth, was taken possession of by the Commissioners
of theNorthern Lighthouses, a coal fire was exhibited
in a chaufi’er,i~'-a description of light which had been
exhibited for 181 years. In 1801, the'light at Har-
wich, in addition to the coal fire, had a flat plate of
. lights.

rough brass on the landward side, to serve as a re-
flector. Such methods of lighting were, of course,
very defective in power, and did not enable the
mariner ‘to ‘distinguish one light from another—a
point which is often of as much importance as the
brilliancy of the light itself.
Previous to the invention of the Argand lamp
(about 17841), the production of a strong and brilliant
light from a single source was scarcely possible. And
even such a lamp, by its unassisted powers, would
not be of very great value in giving early notice to
the mariner of :his approach to the coast, which ought
to be the primary object of a lighthouse. As the
rays from a luminous body proceed in all directions
in straight lines, it is obvious that in the case of a
single lamp, the mariner would derive benefit only
from that small portion of light which proceeded from
the centre of the flame to his eye. The other rays
would proceed to other parts of the horizon, or escape
upwards to the sky, or downwards to the earth, and
thus be of no value to him. By increasing the
number of burners, a small portion of light from each
burner would slightly increase the effective action,
but by far the greatest portion of the light produced
would escape uselessly above and below the horizon,
and also at the back of each flame.
Now, these defects may be remedied, and the effi-
ciency of the light greatly increased, by placing
behind each lamp a reflector, of‘ such a form as to
collect the rays that would otherwise be lost, and
throw them forward to the horizon. The adoption of
such a method has led to what is called the CAT-
OPTRIC 1 system of lights. ‘
Mr. Stevenson states that the earliest notice which
he has been able to find of the application of para-
boloidal mirrors to lighthouses, is in a work on “Prac-
tieal Seamanship,” (étto, Liverpool, 17 91,) by Mr.
William‘ Hutchinson, who notices the erection of the
four lights at Bidstone and Hoylake for the entrance
of the Mersey, in 1'7 63, and describes large para~
boloidal moulds of wood lined with mirror-glass, and
smaller ones of polished tin plate, as in use in those
lighthouses. In France, M. Tculere, a member of
the Royal Corps of Engineers of Bridges and Roads,
is regarded as the inventor of the catoptric system of
In a memoir dated 26th June, 1783, he is
said to have proposed for the Corduan lighthouse a
‘ combination of paraboloidal reflectors with Argand
lamps, ranged on a revolving frame; a plan which
was actually carried into execution under the direc-
tions of the Chevalier Borda. The plan was so suc-
cessful that it was soon adopted in England by the
Trinity House of London; and in Scotland the first
work of the Northern Lights Board, in 1787, was to
light a lantern on the old castle at Kinnaird Head,
in Aberdeenshire by means of parabolic reflectors and
lamps. These reflectors were formed of facets of
mirror-glass placed in hollow paraboloidal moulds of
plaster. '
Referring to what has been already said respecting

(1) From Kcirro'lr'rpov, a mirror ; a compound of Ka'rci, opposite to,
and c’ivr-roptaz, I see.
LIGHTHOUSE.
179
the reflection of rays of heat, [see HEAT, Fig. 1137,]
it will be desirable now to explain a little more fully
the laws of reflection by mirrors.
When luminous rays fall upon any surface which
does not absorb them, they reflect or rebound from
such surface, not precisely after the manner of solid
projectiles, but by a much simpler law, which is
applicable to projectiles only on the supposition that
they move through a vacuum, are endowed with
perfect elasticity, and have no weight. This law of
reflection applies to heat and sound, as well as light ;
in short, to those radiations or effects which are pro-
pagated in straight lines only. Each line or ray
proceeds in a straight line until it meets with a re-
flecting surface, from which it rebounds in another
straight line, the direction of which is determined by
the invariable law, which, for plane surfaces, may be
stated in two parts z—--
I. That the imaginary plane which contains the
ray both before and after reflection (or, as they are
called, the incident and refleeleel rays) is perpendicular
to the reflecting plane. [See I‘IEAT, Fig. 1136.]
11. That the incident and the reflected ray make
equal angles with the reflecting plane, or with a per-
pendicular thereto. [See Fig. 1136.]
When the reflecting surface is curved, we have
only to remember that each mathematical point of
such surface acts precisely as a tangent plane would
do; that is, as a plane touching the curved surface
at that point. Hence, certain regularly-curved re-
flecting surfaces possess some valuable and remarkable
properties. For example: all the radii of a sp/zerz'eal
surface are perpendicular to it, and all meet at one
point. If, therefore, we place a lamp in the centre
of concavity of a concave spherical mirror properly
polished, all the rays of light will be reflected back
to the same point whence they came. Again, an
ellipse bears certain relations to two fixed points
within it, called the fool.‘ One of these relations
is, that a tangent to the curve at any point makes
equal angles with the two lines drawn from that
point to the foci; so that, if a tennis-court were built
in the form of an ellipse, a ball thrown from one of
the foci, in whatever direction, would, alter its re-
bound, proceed directly towards the other focus. Now,
'an oolong sp/ieroz'el 2 possesses this property not only
in a horizontal plane, but in every plane that con-
tains its two foci. Consequently, if we had a hollow
oblong spheroid, with its inner surface polished, all
rays whatever radiating from one of its foci would,
after one rebound, proceed to the other focus, where
they would all meet.
Now if, instead of the whole spheroid, we had only
a portion of one,—-—one end, for example, or a ring
from the middle, or only a portion of such a ring,
however small,—it would still be true of all rays

(1) In the carpenter’s method of drawing an ellipse, by means
of two nails and a piece of string, the nails occupy the focal points.
(2) An oblong spheroid is produced when an ellipse is made to
revolve on its longer axis. 1t resembles an egg, of which both the
ends are alike. Every plane that touches it makes equal angles
with the two lines from the point of contact to the foci,—whence
its peculiar reflecting property.

intercepted by this mirror, and coming from one of its
foci, that they would all be reflected to the other
focus. But as it is not easy to produce such a
spheroidal surface, the remarkable effects produced
by the meeting of all the rays in one point (as noticed
under HEAT, p. 12) are commonly shown in an in-
ferior manner by means of two reflections from two
mirrors which are made as nearly like paraloloz'rls3 as
possible. Now a paraboloid may be regarded as one
end of an oblong spheroid, of which the further focus
is at an infinite distance. i l/Vhen rays, therefore,
radiate from the nearer focus, they are all reflected
towards a point infinitely distant ; that is to say, they
are all rendered parallel; and conversely, any number
of parallel rays coming to such a mirror are all re-
flected so as to meet in its focus.
In reasoning on this subject, we suppose the source
of light to be a mathematical point in the focus of the
mirror; in which case, the rays proceeding in parallel
directions, and not spreading as they proceeded, would
suffer no decrease of power except that which arose
from the very minute resistance of the air. But as
in practice the rays proceed from the innumerable
points of a large flame, only one of which points is in
the focus of the mirror, the rays evidently cannot all
be reflected parallel with its axis. We may here
remark, that the whole effect, whether light or heat,
which radiates from any one point, is called a pencil,
and is of course divisible into an infinite number of
lines or ray/s, all of which are rendered by the reflec-
tion perfectly parallel, and they then constitute a
simple parallel beam. But as the lamp-flame, how-
ever small, emits an infinite number of pencils, one
from each point of its surface, these become after
reflection an infinite number of simple beams; and
although each of these alone does not spread in its
progress, but fills only a cylindrical space of the exact
diameter of the mirror, yet, as all their directions
slightly differ, they altogether form a eonqnoancl beam,
which does spread wider and wider as it proceeds.
Now suppose it were required to exhibit to the
mariner in every part of the horizon pencils of light
at certain intervals of time, separated by periods of
darkness; the best method would evidently be to cause
lamps, placed in the foci of paraboloidal mirrors, to
revolve round a vertical axis, with a velocity suited
to produce the required number of‘ flashes in a given
time. Such an arrangement is shown in the following
figures. The reflectors are made of sheet copper,
plated in the proportion of six ounces of silver to
sixteen ounces of copper. They are moulded to the
paraboloidal form by a delicate and laborious process
of heating with mallets and hammers of various forms
and materials, and are frequently tested during the
operation by the application of a carefully-formed
mould. After having been brought to the proper
curve, they are stifiened round the edge by means of

(3) A paraboloid is produced when a parabola is made to revolve
on its axis. As a parabola may be regarded as a portion out off one
end of an ellipse of infinite length, a paraboloid is one end of an
infinitely long oblong spheroid. Every plane touching it makes
equal angles with two lines drawn from the point of contact, one
to the focus and the other parallel with the axis.
11 2
180
LIGHTHOUSE.
a strong bizzle. and a strap of brass which is attached
to it for the purpose of preventing any accidental
alteration of the figure of the reflector. Polishing-
powders are then applied, and the speculum receives
its last finish. Some idea may be formed of the
amount of labour bestowed upon these reflectors from
the prices paid to the manufacturer 5 namely, for the
large reflectors of 241_inches aperture, 431. each; for
the small ones of 21 inches, 31!. 128. The lamp with
the sliding carriage required for each costs 6!.
The flame generally used in reflectors is from an
Argand fountain lamp, the wick of which is one inch
in diameter. In some
cases the burners are
tipped with silver, to pre-
_ vent the corrosion of the
more common metal from
the great heat evolved.
The burners are also fitted
_ with a sliding apparatus,
which allows them to be
removed from the interior
of the mirror for cleaning,
and returned exactly to
the same place, where they
are locked by a key. By
this contrivance the burner
is always kept in the same
focus, and the lamp can be moved in and out with-
out disturbing the reflector. In Fig. 1336, am re—
presents a section of the reflector, b the burner,
with the glass chimney [2’, and c a cylindrical foun-
tain containing twenty-four ounces of oil: Z is an oil-
cup for receiving any oil that may drop from the lamp.
The oil-pipe, the fountain a, and the burner 6 are
connected withv the rectangular frame (Z, Fig. 1337,
movable in ‘a vertical direction upon the guide-rods
e and f, by which it
can be let down and
the burner lowered
out of the reflector,
by turning the han-
dle g, which forces
‘ a thread on the out—
j side of the guide
1' into a groove in
the frame, or with-
drawing it, which
allows it to slide
down or looks it at
pleasure. In Fig.
1337, the fountain c is represented moved partly
down: 6 e are elongated socket-guides, through
which ‘the ‘guide-rods slide; and f is the guide-rod,
I!’ connected with the perforated sockets on
which the, checking-handle 9 slides. The
oil-cup’ Z, when covered with a lid and wick-
Z holder, as shown in Fig. 1338, also serves
_ I as a float-lamp in winter, when the ,oil is
Fly‘ 1338‘ liable to congeal. It is ‘attached to the
lower part of the oil-tube-by the arm 71, and is lighted
about an hour before sunset, so as to prepare the

Fig. 1336.
‘s
‘—-_-___
p s\

Fig. 1337.

large lamp for lighting‘ at the proper time. ' The com-
munication between the burner and the fountain is
easily opened or shut by simply giving the fountain a
turn of one quadrant round its own vertical axis, by
means of the round knob at its top, thereby moving
a slide-valve which shuts ofl' the communication
between the fountain-tube
and the lamp-tube. [See
LAME] By this means, the
oil is cut ofl about fifteen
minutes before extinguishing
the‘ lights, so that when that
is done, the burner is quite
free from oil. The wick is
raised and depressed by a
rack and pinion, as noticed
under LAMP. An elliptical
aperture, 2 inches by 3, is
cut in 'the upper and lower
part of the reflector; the
lower serving for pthe free
ingress and egress of the
burner, and the upper, to which the copper tube it is “Z-
attached, serving for ventila- _
tion. At 6 is a portion of Fly‘ 1339'
the main bar of the chandelier or frame on which the
reflectors are ranged, each being made to rest on
knobs of brass, one of which, shown at is is, Fig. 1339,
is soldered to the brass band Z, that clasps the ex-
terior of the reflector.
The oil generally used in the lighthouses of the
United Kingdom is the sperm oil of commerce. In
France, the colza oil, which is expressed from the
seed of a species of wild cabbage (Brassz'ca olemcea
0012a), and the olive oil, are chiefly used. Colza oil
has recently been adopted in many of the British
lights, and has led to an important saving, as its com-
bustion produces an equal quantity of light at little
more than one-half of the expense of sperm oil. It
also possesses over sperm oil other advantages, which
were stated by Stevenson in his Report on this sub-
ject to a select Committee of the House of Commons
on Lighthouses, 10th March, 1847. It remains fluid
at temperatures at which sperm oil thickens: its

illuminating power is somewhat superior to that of '
sperm oil, in the ratio of 1056 to 1. It burns both
in the Fresnel lamp and the single Argand burner,
with a thick wick, during 17 hours, without requiring
any coaling of the wick or any adjustment of the
damper, and the flame appears to‘ be more steady than
that produced by sperm oil. This greater steadiness
of the colza-oil flame involves less breakage of the
glass chimneys than with sperm oil. The consump-
tion of oil in the Fresnel lamp is stated at 121 for
colza, and 114! for sperm: in the Argand lamp, 910
for colza, and 902 for sperm. Assuming the means of
these numbers, 515 vfor colza, and 508 sperm, as re-
presenting the relative expenditure of these oils, and
if the price of colza be 38. 9d. and sperm (is. 9d. per
gallon, the saving is' in the ratio of 1 to 1'7 55,
which at the present rate of supply for the Northern
LIGHTHQUSE.
181
— Lights would give a savlng of about 3,266l. per
annum. It should be stated, that in the use‘of colza
oil in lamps which had previously burned sperm, the
burners require to be reconstructed so as to receive
thick wicks of brown cotton.
The number of lights on a much-frequented coast
being considerable, it is of the utmost importance to
arrange them so as to enable the mariner easily to
distinguish them from each other. Catoptric lights
admit of nine separate distinctions: 1, fixed, 2, re~
volving white, 3, revolving reel and while, 4:, revolving
reel with two whites, 5, revolving while wiih izvo reels,
6, flashing, '7, intermittent, 8, cloahlefia'ecl lights, 9,
doable revolving while lights. Mr. Stevenson thus
defines their distinctive features :—“ The first exhi-
bits a steady and uniform appearance, which is not
subject to any change; and the reflectors used for it
are of smaller dimensions than those employed in re-
volving lights. This is necessary in order to permit
them to be ranged round the circular frame, with their
axes inclined at such an angle as shall enable them
to illuminate every point of the horizon. The revolving
light is produced by the revolution of a frame with
three or four sides, having reflectors of a larger size
grouped on each side with their axes parallel ; and as
the revolution exhibits once in two minutes, or once
in a minute, as may be required, a light gradually
increasing to fall strength, and in the same gradual
manner decreasing to total darkness, its appearance is
extremely well marked. The succession of reel anzl
white lights is caused by the revolution of a frame
whose different sides present red and white lights;
and these afford three separate distinctions, namely,
alternate red and white; the succession of two white
lights after one red; and the succession of two red
lights after one white light. The flashing light is
produced in the same manner as the revolving light;
but owing to a different construction of the frame,
the reflectors on each of eight sides are arranged with
their rims or faces in one vertical plane, and their
axes in a line inclined to the perpendicular; a dispo-
sition of the mirrors which, together with the greater
quickness of the revolution, which shows a flash once
in five seconds of time, produces a very striking
effect, totally different from that of a revolving light,
and presenting the appearance of the flash alternately
rising and sinking. The brightest and darkest periods
being but momentary, this light is further charac-
terised by a rapid succession of bright flashes, from
which it gets its name. The intermittent light is dis-
tinguished by bursting suddenly into View and con—
tinuing steady for a short time, after which it is
suddenly eclipsed for half a minute. Its striking
appearance is produced by the perpendicular motion
of circular shades in front of the reflectors by which
the light is alternately hid and displayed. This dis-
tinction, as well as that called the flashing light, is
peculiar to the Scotch coast. The double lights
(which are seldom used except where there is a neces-
sity for a leacling line, as a guide for taking some
channel, or avoiding some danger) are generally ex-
hibited from two towers, one of which is higher than

the other. At the Calf of Man a striking variety has
been introduced into the character of leading lights,
by substituting for two fired lights, two lights which
revolve in the same periods, and exhibit their flashes
at the same instant; and these lights are, of course,
susceptible of the other variety enumerated above,
that of two revolving red and white lights, or flashing
lights, coming into view at equal intervals of time.
The utility of all these distinctions is to be valued
with reference to their property of at once striking
the eye of an observer, and being instantaneously
obvious to strangers. ‘The introduction of colour, as
a source of distinction, is necessary in order to obtain
a suflicient number of distinctions; but it is in itself an
evil of no small magnitude; as the effect is produced
by interposing coloured media between the burner
and the observer’s eye, and much light is thus lost by
the absorption of those rays which are held back in
order to cause the appearance which is desired. Trial
has been made of various colours; but red, blue, and
green alone have been found useful, and the two
latter only at distances so short as to render them
altogether unfit for sea-lights. Owing to the depth
of tint which is required to produce a marked effect,
the red shades generally used absorb from gths to
g-ths of the whole light,--an enormous loss, and suffi-
cient to discourage the adoption of that mode of dis-
tinction in every situation where it can possibly be




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Fig. 1340- ELEVATION or a
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4
THE CATOPTRIC ranscrpnn.



avoided. The red glass used in France absorbs only
#115 of the light ; but its colour produces, as might
be expected, a much less marked distinction to the
182
.Lrenrnousn.
seaman’s eye. In the lighthouses‘ of Scotland, a
simple and convenient arrangement exists for colour-
ing the lights, which consists in using chimneys of
red glass, instead of placing large discs in front of the
reflectors.”
The arrangement of a revolving apparatus on the
catoptric principle is shown in Figs. 134:0, 134d. rz 92
represents the reflector frame, or chandelier; 0 0 the
reflectors with their oil-fountains 12 12 : the whole is
attached to the revolving axis or shaft q, the pivot of
0 0
© © @

Fig. 1341.
which turns in a cup supported by a cast-iron bracket
Z: the shaft is also supported by cross bars at s s;
m m are bevelled wheels for conveying motion to the
shaft by means of common clockwork machinery
moved by a descending weight. The copper venti-
lating tubes, r r, convey away the heated products of
combustion; and u u is a copper pan for receiving
any moisture which may happen to enter at the cen-
tral ventilator in the roof of the light-room.
Fig. 1342 is a plan of one tier of reflectors
arranged for a fixed catoptric light. In order to dis-
tribute the light as equably as possible, the other tiers


‘ Fig. 1342.
are so, arranged that _ their axes ‘divide into equal
angles the arcs intercepted between the axes of the
adjoining reflectors on the first tier. In this figure
'22 vrz represents the chandelier, q the fixed shaftin the

centre, supporting the whole, 0 0 the reflectors, and
pp the lamp-fountains.
“ In lighthouses of moderate height the proper
position for the reflector itself is perfect horizontality
of its axis, which may be ascertained with sufficient
accuracy by trying, with a plummet, whether the lips
of the instrument, which we may conclude to be at‘
right angles to the plane of its axis, be truly vertical.
In light-rooms very much elevated above the sea,
however, the dip ofv the horizon becomes notable; and
a slight inclination forwards should be given to the
face of the reflectors, so that their axes produced may
be tangents to the earth at the visible horizon of the
light-room; an arrangement which, in practice, may
be easily ‘made by reflecting the sea horizon, in a small
mirror placed at the focus, and inclined at 45° to the
axis of the paraboloid, so that the image of the sea-
line may reach the eye in the line of the parameter.
The dip of the reflector, however, must not be per—
mitted to interfere with the perfect horizontality of
the top of the burner, which is indispensable to its
proper burning.”
Various other forms and arrangements of parabolic
mirrors have been contrived for lighthouses and bar-
bour lights, but our limited space will not allow us
to describe them.
We come next to notice what is called the
Drorrnrc system of lights.1 In the eetoptrz'e system,
as already explained, the light is reflected from a
surface formed in such a way as to cause all the rays
to proceed in one'and the same required‘direction. In
the dz'optrz'e system the rays are made to pass through
lenses, by whichv they are bent or reflected from their
natural course into that which is desired. The same
object is attained by either system, only in the one
case the light is reflected, and in the other it is re-
fmeted.
One of the earliest notices of the application of
lenses to lighthouses, is by Smeaton in his narrative
of the Eddystone Lighthouse, where it is mentioned
that a London Optician proposed to grind the glass of
the lantern to a radius of 7%,; feet. But before this
lenses had actually been tried in several lighthouses
in the north of England, and in particular at the
South Foreland in 1752; but their imperfect figure,
and the quantity of light absorbed by the glass,
rendered their effects so much inferior to that of the
paraboloidal reflectors as to lead to their being aban-
doned for a time‘. Indeed the obstacles in the way
of forming accurate lenses» of large size and in one
piece may be fairly pronounced insurmountable; for
in the first place,,.pu,re._flint glass free from strz'ee, lerzots,
t/zreads and tears,‘ cannot be ‘produced in sufficient
abundance for a large solid lens [see GLASS, Section
V.]: secondly, it cannot be cast into a lenticular form
without ' flaws and impurities which grinding and
polishing will not remove; thirdly, the great increase
of thickness in the centre consequent on an increase
in diameter of the lens, opposes the transmission of
the luminous rays, and by increasing the aberration

(I) Probably from eimrrpcv, an optical instrument with holes for
looking through: from 6rd, through ,' arr-royal, I see.
. LIGHTHOUSE.
183
dissipates'the rays at the focal point. In order to‘
get rid of these ‘objections, Buifon proposed that a
solid lens of large size having been formed, the parts
not necessary to the general optical effects should be
cut away. For example, in the solid lens of the
section A mp BEDA, Fig. 1343, it was proposed to
cut out all the glass left white in the figure, namely,
the portions between en p and no, and between no
and the left-hand surface of DE. A lens thus con-
structed would be incomparably superior to the solid
one, but it would be very difficult to polish the
surfaces A m, 13 p, c n, F o, and the left-hand surface
of DE; and after all some of the greatest blemishes
in the glass might be left in the lens thus formed.
It was therefore a capital suggestion to build up


N
Fig. 1.343. Fig. 1344.
lenses of any size of separate zones or rings, each of
which might be composed of separate segments, as
shown in the front view of ' the lens, Fig. 134a} Such
a lens is composed of one central lens AB 0 D, corre-
sponding with its section 1) n, Fig. 13413 ; of a middle
ring en LS, corresponding to on E r, Fig. 134.3, and
consisting of four segments ; and another ring, N r M T,
corresponding ton c r B, and consisting of eight seg—
ments. Such lenses, named by Sir David Brewster
poly/zonal, can be formed of large size, and by making
the foci of each zone coincide, the spherical aberration
can be corrected or nearly so. This invention was
followed up by Fresnel, who, in conjunction with
Arago and Mathieu, placed a powerful lamp in the
focus of the lens, and applied it to the practical pur-
poses of a lighthouse. Fresnel also determined the
radius and centre of the curvature of the generating
arcs of each zone, centres which continually recede
from the vertex of the lens in proportion as the zones
to which they refer are removed from its centre; and
the surfaces of the zones, consequently, are not, as in
Buffon’s lens, parts of concentric spheres. It de-
serves notice that the first lenses constructed for
Fresnel by M. Soleil, had their zones polygonal, so
that the surfaces were not annular, a form which
Fresnel considered less accommodated to the ordinary
resources of the Optician. He also, with his habitual
penetration, preferred the plane-convex to the double-
convex form, as more easily executed. After mature
consideration, he finally adopted crown glass, which,

(1) This suggestion was first made by Condorcet in his “ Eloge
de Bufi‘on,” published in 1773; secondly, by Sir David Brewster
in 1811 ;- and thirdly, by Fresnel in 1822. They all appear to have
been perfectly original and independent suggestions. ‘

notwithstanding its greenish colour, he preferred to
flint glass, as being more free from striae. All his
calculations were made in reference to an index of
refraction of 151, which he verified by repeated
experiments. The instruments have received the
name of annular lenses, from the figure of the surface
of the zones.”
The Dutch first followed the French in introducing
the system of Fresnel into their lighthouses. In
18% the Commissioners of the Northern Lighthouses
sent their engineer, Mr. Robert Stevenson, to France,
and to report upon the lights of that country, which
he did within the same year, and also procured lenses
from France for the purpose of instituting experi-
ments. In a report dated 30th Dec.1825, he recom-
mended the adoption of lenses. It was not, however,
until 1834i that the commissioners took decisive steps
for deciding the comparative merits of the catoptric
and dioptric systems. In that year Mr. Alan Steven-
son was commissioned to visit France, and make
himself perfectly acquainted with the dioptric system,
and the result of his report was such, that on his
return the Commissioners authorized him to remove
the reflecting apparatus of the revolving light at
Inchkeith, and to substitute dioptric instruments in
its place, a change which was completed and the light
exhibited on the evening of the 1st October, 1835.
The light was so highly satisfactory that a similar
change was made at the fixed light of the Isle of
May. The Trinity House next adopted the system
for England, and employed Mr. Alan Stevenson to
superintend the construction of a revolving dioptric
light of the first order, which was afterwards erected
at the Start Point in Devonshire. After this time
the system became common.
Referring to our article LIGHT for a notice of the.
laws of refraction and the action of lenses upon
luminous rays, it will be sufficient to remind the
reader of the following properties of a plano-convex
lens such as Ll, Fig. 13%. far is the optical axis
of the lens, or the line in which a ray of light passes
through the lens with- I,
out any change of direc' '
tion, in consequence of 5-‘
its being normal to both
surfaces. f is the prin-
cipal focus or the point
where the rays r a‘ 9*, which fall parallel to the optic.
axis on the outer face of the lens, meet after refrac-
tion at the two faces. Or if we suppose f to be a.
point of light, the rays proceeding from it in their
naturally divergent course fall on the inner surface
LAZ of the lens, and are so changed by refraction
there and at the outer face, that they finally emerge
parallel to the optic axis in the direction L9‘, l9".
A spherical lens’ collects truly into the focus only
those rays which are incident near the axis, and
hence it is of importance to employ as a lens only
a small segment of a sphere. This circumstance,
among others, led to the suggestion of building
up lenses in separate pieces, and Fresnel, as already
noticed, showed how the subdivision was to be


I
,l.

t
Fig. 1345.
1184:
Lien'rnoujsn
made. In his ‘large lens employed ' in lights of the
first order, the focal distance of which is 920 milli-
metres, or 36'22 ‘inches, the central disc is .ahoutylilvi
inches in diameter, -_and the annular rings surround it gradually decrease‘ in breadth: as? they
necede from. the axis, from 72% to li—jinches.¢ QThe
breadth of any zone. or ring may, however, be left’; to
choice, but‘ no ‘part of ‘the lens should be much
thicker than the rest, otherwise there would‘fbe
inconvenient projectionsv on its ~surfaee,and' the .lallo'ss'"
of!” light by- absorption would be'runequaln the
first! lenses the. zones,.werezrunite'gliey Tmeans--pf4~.-sn1a11_
d’owelsor joggles of passing, from‘ the one
zone into theother, b‘utQtheFr-en'ch artists have now
attained such exactness their- work'- ‘as-to" dispense
with such fixtures, and thevariousr parts ‘of; . the
compound lens, weighing upwards~ ‘of lbs. and
presenting about 1,300 square inches :of surface,‘-
it
I
-- I ImwllllllH1llllllllllllllllllllllllllmlllllllllll 1‘ .f
I





j l \. _
T h .
_' _: u \ _
- 1 ullfi


at
Fig. 1346. ANNULAR LENS; onrrnn' :rms'r, onnmn

-_ .-_ --.‘_. __.‘_\ _... l-.__._--___._-'
l I III lllllllllllllllllll illulllllullll" "I" ‘I
‘area now bound together solely'by a metallic frame,
‘Fig-113416.‘, and the close union between the concentric
'3 faces-n of the rings, although the surfaces in contact
wiltliieach other’ are only §+i~nch in depth. _ _
Ale? to the illuminating ‘powers-of 5thef1enses, Mr.
Stevenson says, “ We shall not ,greatlyierr we con-l
sid'e‘rv the quotient of the surface of ‘the lens‘ divided
by tlie surface of the flame," as the increased power of
illumination by the use of the lens. The illuminating
efl'ectl of the great lens, as measured at'moderatedis-
tances, has generally been taken at 3,000.. Argand
flames, the value of the ‘great flame; in its-focus ‘being
about? 16, thus giving its increasinggpower- a‘snearly.
equalli to 180. The more perfect lensejsihave produced i v ‘A
attached to the backs of the brass cases, afford the
a'consid'erab‘ly greater efl’ec’ .” p _ - . j ~ the application of lenses to‘ lighthouses, they
are arranged round a central lamp placed; ‘on-the level
f o'ftlieir’focal plane, as shown in Plate 1, thusforming '
by their union a right octagonal hollow prism circu-v
lating; roundfthe fixed central flame, and showing to
a distant observer successive flashes or blazes of light
. whenever-one of its. faces crosses a-line. joining his.
eye-"andfthe lamp.‘ Thus the action is somewhat
similar to. that of the mirrors‘ 5 but the blaze produced-
by ‘the, lens isof greater intensity and shorter duraqr
tiong"; the" latter quality being proportional to the"
divergence ‘of z the resultant beam. “ Each lens sub-
tends~_-.. a central“ horizontal pyramid of light _, of'
about‘? ‘ 416° "of! inclination, beyond which limits thev

flenticular action could not be advantageously pushed,
owing to the extreme obliquity of the incidence
of light; but Fresnel at once conceived the idea
"of pressing into the service of the mariner, by means
of‘; two very simple expedients, the light which would
otherwise have uselessly escaped above and vbelow
the ~lenses. For intercepting the upper portion of
~the alight, he employed eight smaller lenses of
500‘ mm. focal distance (1968 inches) inclined in-
igwards towards the lamp, which is also their common
'f99fl35j3nd- thus 'fpr'ming by theirunion a frustum
Of 00 Of 111011118»-
i'tiolig Theflightjfalliljlg' on those lenses is formed
‘into. eight beams . rising ‘upwards at an angle of 50°
inclination: .' Above "them ' are arranged eight plane
mirrors, so inclined (s'ee' Plate I.) as to project
,'.the beams transmitted by the small lenses into the
-- horizontal direction, and thus finally to increase the
effect of-1____1i'ght. In placing those upper lenses,
it is genei'allythought advisable to give their axes
a horizontal direction of 7° or 8° from that of the
great .lenses‘,"-and in the direction contrary to that of
the revolution of. the frame which carries the lenti-
cular apparatus, ‘j By this arrangement, the'flashes of
the smallertlens'es precede those of the large ones,
and thus tend-to correct the chief practical defect of
v revolving 1entieu1ar lights, by prolonging the bright
periods. ._ .' .1: to certain arrangements of the
apparatus, which are necessary for the efficiency of
the lamp, but§a small portion of those rays vwhich
escape from - below the lenses can be rendered avail_
able forpthe, purposes of a ‘lighthouse ; and any
attempt to subject them to lenticular action, so as to
add them to ‘the, periodic flashes, would have led to
a most inconvenient complication of the apparatus.
Fresnel adopted the more natural and simple course
of transmitting them to the horizon in the form of
flat rings of light, or rather of divergent pencils,
directed to various points of the horizon. This he
effected by means of small curved mirrors, disposed
in tiers one above another, like the leaves of a
. Venetian blind, an arrangement which he also adopted
I‘ for intercepting the light which escapes above as well
as below the dioptric belt in fixed lights. The mirrors
are plates of glass silvered on the back, and set in
flat GEUSQS of sheet brass. They are suspended on a
circular frame by means of screws, which being
means,‘ of adjusting ‘them to their true inclination, so
that’ they maxl‘efiset, obiests, 911. the harizon 0f the
to 3.11 Observer’s eye placed in’ the common
focus, of the system)’.
,"Plj'atei I. represents a revolving dioptric apparatus,
r‘ is iliQ focal pointv in which the flame is
placed; Iran large annular lenses ' forming by their
unionianr octagonal, prism, with the lamp in its axis,
andpprojiectiligij horizontal beams the light which
.i'leceivewlfrhin. the focus. L’ L’ ‘are the upper
lenses-,foriniiig by their’ union a frustum of an octa- '
gonallpyrarnidof 50° of inclinatiomand having their
fOCi Corresponding the point F.- They parallelise
the "rays of which pass over the lenses.- in M

..‘.
mac.‘ :1 i.

a“ ' ‘I
of
.“1
Q:

LIGHTHQUSE.
185
are the plane mirrors placed above the pyramidal
lenses L’ L’, and so inclined as to project the beams
reflected from them in planes parallel to the horizon.
z z are the lower zones substituted by Mr. Stevenson
for the curved mirrors, as will be further noticed
presently. The lower part shows the movable frame-
work, which carries the lenses, and mirrors, and
the rollers on which it circulates, with the clock-work
for giving motion to the whole.
Plate 11. represents a fixed catadioptric apparatus.
In this as well as in the former case the lamp is, of
course, in the centre, but in the first case the lenses
form an octagonal hollow prism circulating round the
flame; and in the second case, a polygonal hoop con-
sisting of a series of refractors infinitely smaller in
their length, and having their axes in planes parallel
to the horizon. Such a continuation of vertical sec-
tions, by refracting the rays proceeding from the focus
only in the vertical direction, must distribute a zone
of light equally brilliant in every point of the horizon.
This effect will be easily understood by considering
the middle vertical section of one of the great annu-
lar lenses already described, abstractedly from its re-
lation to the rest of the instrument. It will readily be
perceived that this section possesses the property of
simply refracting the rays in one plane coincident
with the line of the section, and in a direction parallel
to the horizon, and cannot collect the rays from either
side of the vertical line; and if this section by its
revolution about a vertical axis becomes the gene-
rating line of the enveloping hoop above noticed,
such a hoop will of course possess the property of
refracting an equally diffused zone of light round the
horizon. The difficulty, however, of forming this
apparatus appeared so great, that Fresnel determined
to substitute for it a vertical polygon composed of
what have been improperly called eglinclrie lenses, but
which in reality are mixtilinear prisms placed hori-
zontally, and distributing the light which they receive
from the focus almost equally over the horizontal
sector which they subtcnd. This polygon has a
sufficient number of sides to enable it to give, at the
angle formed by the junction of two of them, a light
not very much inferior to what is produced in the
centre of one of the sides; and the upper and lower
courses of curved mirrors are always so placed as
partly to make up for the deficiency of the light at
the angles. The effect sought for in a fixed light is
thus obtained in a much more perfect manner than by
any conceivable combination of paraboloidal mirrors.
. . . The disadvantage of the polygon lies in the
excess of the radius of the circumscribing circle over
that of the inscribed circle, which occasions an un-
equal distribution of light between its angles and
the centre of each of its sides; and this fault can
only be fully remedied by constructing a cylindric
belt, whose generating line is the middle mixtilinear
section of an annular lens revolving about a vertical
axis passing through its principal focus. This is, in
fact, the only form which can possibly produce an equal
diffusion of the incident light over every part of the
horizon. Such an apparatus as is here indicated, was

constructed under the directions of Mr. Alan Ste-
venson for the Isle of May light. It was of a truly
cylindric form, with its central belt in one piece, and
the joints of each panel inclined to the horizon at
such an angle as to render the light perfectly equal
in every azimuth. See Plate II.
Another improvement which we owe to Mr. Ste—
venson, was the substitution of totally reflecting
prisms for the mirrors before employed in conjunction
with the lenses. Mirrors have the objection of occa-
sioning loss of light by reflection, and of being
composed of perishable materials as regards their
polish. Such a catadioptric apparatus was con-
structed by M. Soleil, at Paris, and tested by
M. Leonor Fresnel, at the Royal Observatory of
that city, when the illuminating effect of the cupola
of zones was found to be to that of the seven upper
tiers of mirrors of the first order, as 14.0 to 87.
This apparatus, which was fitted up in the Skerryvore
Lighthouse, and is represented in Plate 11., consists
of a central dioptric belt of refractors, n E r, forming
a hollow cylinder of 6 feet in diameter and 30 inches
high; below it are six triangular rings of glass, A’ B’ c’,
or catadioptric zones, ranged in a cylindrical form,
and above, a crown of 13 rings of glass, A 13 c, the
whole forming by their union a hollow cage composed
of polished glass 10 feet high and 6 feet in diameter.
In the lower catadioptric zones one division is omitted,
to allow free access to the lamp. 1‘ is the focus with
the lamp~flame. x x x are diagonal supports for the
upper catadioptric zones; H H a service-table, on
which the lamp rests, and on which the keeper stands
to trim the burner: this table is supported by a pillar
resting on the light-room floor.
The single central lamp required for dioptric ap-
paratus must be so constructed as to afford a large
volume of flame, for which purpose the burner is made
to consist of four concentric wicks, as shown in plan
and sectional elevation, Figs. 134.7, 1348. The inter—
vals between the wicks, which admit currents of air,

' .Fz'g. 1347.
diminish a little in width as they recede from the
centre. 0 c’ 0" c'” are the rack handles for raising
or depressing the wicks. A B is the horizontal duct
which leads the oil to the four wicks: L L L are small
tin plates by which the burners are soldered to each
other, so placed as not to hinder the free passage of
186
LIGHTHOUSE.
air: 1? is a clamping screw for maintaining at its pro-
per level the gallery is n, ~which carries the glass





(UH/pig; _ its

l
chimney E, Fig. 134:9, above which is a sheet-iron
cylinder 13‘, which serves to increase the length of the
chimney, and within it is a small damper D, capable
of being turned by a handle for regulating the
draught; 13 is the pipe which conveys oil to the
wicks. The excessive heat which would be produced
by the concentric flames is checked
1: by means of a superabundant
supply of oil thrown up from a
C§===O cistern below by a clock-work
D
movement, and made constantly
to overflow the wicks as in the
mechanical lamp of Carcel. By
this means the wicks are pre-
vented from rapid carbonization,
and when kept well supplied with
colza oil, they have been known
to maintain for 17 hours a full
flame without requiring to be
touched. The only risk in using
such a lamp arises from the lia-
bility to occasional derangement
of the leather valves, that force
the oil by means of clock-work.
This may lead to the extinction
of the lamp; and in order to warn
the keeper of so serious an acci-
Fig. 1348.





B
Fig. 1349.
. dent, there is attached to the lamp an alarm, con-
sisting of a small cup pierced in the bottom, which
receives part of the overflowing oil from the wicks,
and when full, balances a weight placed at the op-
posite end of a lever. The moment the machinery
stops, the cup ceases to receive the supply of oil, and
the remainder running out at the bottom, the equili-
brium of the lever is destroyed, so that it falls and
disengages a spring which rings a bell sufficiently
loud to waken the keeper, should he happen to be
asleep. Stevenson, thinking it not unlikely that
this alarum might tempt the keepers to relax in their
watchfulness' and fall asleep, has adopted in all the
lamps of the dioptric' lights on the Scotch coast the
converse mode ‘of causing the bell to cease ringing
when the clock-work stops. Another precaution is to
have in the light-room a spare lam p trimmed and

adjusted to the height for the focus, which may
be lighted and substituted for the other in case of
accident. The most advantageous heights for the
flames in dioptric lights vary from 4.33 to 3'15 inches.
The lamp-pumps should raise four times the quantity
of oil actually consumed in maintaining the flame
during a given time, to prevent the wick from being
carbonized too quickly.
The expense of the various parts of the Dioptric
apparatus is as follows :—great lens of first order, 58!.
(8 of which are required); pyramidal lens and mirror,
14kt. 12.9. (8 of which are required); catadioptric
cupola for 360° of horizon, 4180!. ; catadioptric rings
below lenses, 3602.; panel of dioptric belt for fixed
lights of first order, 56L (of which 8 are required for
the whole circle); apparatus of fourth order for a
fixed light for whole horizon, 1281. ; apparatus of
sixth order for a fixed light for whole horizon, 4.4!.
The expense of the mechanical lamp of the first order,
with four wicks, (with framed tripod and adjusting
screws as made for the Scotch lighthouses,) is 301.
The dioptric lights used in France are divided into
six orders, which refer to their power and range, and
not to their characteristic appearances. Lights of the
first order have an interior radius of focal distance of
86'22 inches (92 cm.), and are lighted by a lamp of
four concentric wicks, consuming 570 gallons of oil
per annum. Lights of the second order have an
interior radius of 27'55 inches (70 cm.), and are
lighted by a lamp of 3 concentric wicks, consuming
384! gallons of oil per annum. T/n'rd order: focal
distance 19'68 inches: the lamp has two concentric
wicks, and the annual consumption of oil is 183
gallons. Fourth order, or kartour Zip/its: internal
radius 984: inches: lamp with 2 wicks, consumes
about 130 gallons of oil per annum. Fg'ft/z order:
focal distance 7 ‘28 inches. Sizer/‘h order: internal radius
5'9 inches. The lamp has an Argand burner, and con-
sumes 48 gallons of oil per annum. Each order
admits of certain combinations which produce various
appearances, and form the distinctions used for di-
optric lights. The ‘first order contains—1, lights
producing once every minute a great flash, preceded
by a smaller one, by the revolution of 8 great lenses
and 8 smaller ones, combined with 8 mirrors. 2,
lights flashing once in every half minute, and com-
posed of 16 half lenses. The subsidiary parts of
such lights may be simply catoptric or diacatoptric.1
3, fixed lights composed of a combination of cylindric
pieces with curved mirrors or catadioptric zones
ranged in tiers above and below them. The second
order comprises revolving lights with 16 or 12 lenses,
which make flashes every half ‘minute ; and fixed
lights varied ‘by flashes once in every 41 minutes, an
effect which is produced by the revolution of cylindric
refractors with. vertical axes ranged round the out-
side of the fixed light apparatus. The t/cz'rd order
contains common fixed lights, and fixed lights varied
by flashes once in every 41 minutes. The fourth order

(1) Mr. Stévenson refers the term diacafoplric to the arrange-
ment of pyramidal lenses and plane mirrors, by which the light is
first refracted and then reflected. '
LIGHTHOUSE. "
187
contains simple fixed lights, and fixed lights varied
by flashes once in 3 minutes. The j/flb order has
fixed lights varied by flashes once in every 3 minutes,
and fixed lights of the common period.1 The sz'rclb
order contains only fixed lights. In consequence of
the great loss of light resulting from the application
of coloured media, distinctions based upon colour
have generally been discarded in the French lights.
Having thus stated the chief characteristic features
of the two systems of lights, we append a few general
conclusions as to their comparative merits, referring
to Mr. Stevenson’s work for the facts and reasonings
upon which they are based. It appears, 1st, that
by placing 8 reflectors upon each face of a revolving
frame a light may be obtained as brilliant as that
derived from the great annular lens; and that in the
case of a frame of three sides, the excess of expense
by the reflecting mode would be 63l. 188., and in the
case of a frame of 4; sides the excess would amount
to 225L
revolving lights which illumine every point of the
horizon successively, the lens is more advantageous
than the reflector in the ratio of 36 to 1. 3d, That
the divergence of the rays from the lens being less
than from the reflector, it becomes diflicult to produce
by lenses the appearance which characterises the
catoptric revolving lights, already so well known to
British mariners; hence any change of existing lights
would involve some practical objections, which, how-
ever, would not apply in the case of new lights. 41th,
That the uncertainty in the management of the lamp
renders it more difficult to maintain the revolving
dioptric lights without risk of extinction. 5th, That
the extinction of one lamp in a revolving catoptric
light is not only less probable, but leads to much less
serious consequences than the extinction of the single
lamp in a dioptric light; because in the first case,
the evil is limited to diminishing the power of one
face by an eighth part; while in the second, the whole
horizon is totally deprived of light.
A comparison of the fixed dioptric and the fixed
catoptric has led to the following summary of results:
——1st, It is impossible, by any practicable combina-
tion of paraboloidal reflectors, to distribute round the
horizon a zone of light of exactly equal intensity;
but this may be easily effected by dioptric means.
In other words, the qualities required in fixed lights
cannot be so fully obtained by reflectors as by refrac-
tors. 2d, The average light produced in every azi-
muth by burning one gallon of oil in Argand lamps,
with reflectors, is only about one-fourth of that pro-
duced by burning the same quantity in the dioptric
apparatus, and the annual expenditure is léOl. 38. Ba.
less for the entire dioptric than for the catoptric
light. 3d, The characteristic appearance of the
fixed' reflecting light in any one azimuth would not
be changed by the adoption of the dioptric method,
although its increased mean power would render it
visible at a greater distance in every direction.

(1) The term “ fixed lights varied by flashes,” has been changed
for “ fixed lights with short eclipses,” because it has been found
that, at certain distances, a momentary eclipse precedes the flash.
2d, That for burning oil economically in.

4th, From the equal distribution of the rays, the
dioptric light would be observed at equal distances
in every point of the horizon; an effect which cannot
be fully attained by any practicable combination of
paraboloidal reflectors. 5th, The fixed apparatus
being more simple than the revolving, an accident to
the mechanical lamp is sooner rectified. 6th, The
extinction of a lamp in a catoptric apparatus leaves
only glgth part of the horizon without light; but the
extinction of the single lamp of the dioptric arrange-
ment deprives the whole horizon of light. 7th, In
certain situations a risk arises from irregularity in the
distances at which the same fixed catoptric light can
be seen in the different azimuths, a defect which does
not exist in the dioptric light.
It appears, therefore, that the dioptric system is in
most cases to be preferred to the catoptric. It has
been already stated that in the catoptric arrange-
ment the size of the flame, and its distance from the
surface of the reflector, are of great importance, and
that the divergence of the resultant beam materially
affects its fitness for the purpose of a lighthouse. So,
also, with the lens: unless the diameter of the flame
of the lamp has to the focal distance of the instru~
ment a relation such as may cause an appreciable
borz'zonlal divergence of the rays refracted through it,
it could not be usefully applied to a lighthouse: for,
without this, the light would be in sight during so
short a time that the seaman would have much difli-
culty in observing it. Nor must the consideration
of vertical divergence be altogether overlooked. Al-
though such divergence above the horizon involves
a total loss of the light which escapes uselessly up-
wards into space, “ yet if the sheet of light which
reaches the most distant horizon of the lighthouse,
however brilliant, were as thin as the absence of all
vertical divergence would imply, it would be practi-
cally useless; and some measure of dispersion in the
are below the horizon is therefore absolutely indis-
pensable to constitute a really useful light. In the
reflector the greatest vertical divergence below the
horizontal plane of the focus is 16° 8', and that of
the lens is about 4° 30’. The powerful beam of light
transmitted by the lens peculiarly fits it for the great
sea-lights, which are intended to warn the mariner of
his approach to a distant coast which he first makes
on an over-sea voyage; and the deficiency of its diver-
gence, whether horizontal or vertical, is not practically
felt as an inconvenience in lights of that character,
which seldom require to serve the double purpose of
being visible at a great distance, and at the same
time of acting as guides for danger near the shore.
For such purposes the lens applies the light much
more advantageously, as well as more economically,
than the reflector; because, while the duration of its
least divergent beam is nearly equal to that of the
reflector, it is eight times more powerful. A revolving
system of 8 lenses illuminates a horizontal are of 32°
with this bright beam. The reflector, on the other
hand, spreads the light over a larger arc of the hori—
zon; and while its least divergent beam is much less
powerful than that of the lens, the light which is shed
188
LIGHTHOUSE.
over its eczfreme arc is so feeble as to be practically
of no use in lights of extensive range,'even during
clear weather. When a lighthouse is placed on a very
high headland, however, the deficiency of divergence
in the vertical direction is often found to be pro-
ductive of some practical inconvenience; but this
defect may. be partially remedied by giving to the
lenses a slight inclination outwards from the vertical
plane of the focus, so as to cause the most brilliant
portion of the emergent beam to reach the visible
horizon which is due to the height of the lantern. It
may be observed, also, that a lantern at the height of
150 feet, which (taking into account the common
height of the observer’s eye at sea) commands a range
of upwards of 20 English miles, is sufficient for all
the ordinary purposes of the navigator, and that the
intermediate space is practically easily illuminated
even to within a mile of the lighthouse, by means of
a slight inclination of the subsidiary mirrors, even
where the light from the principal part of the appa-
ratus passes over the seaman’s head. For the pur-
pose of leading lights, in narrow channels, on the
other hand, and for the illumination of certain narrow
seas, there can be no doubt that reflectors are much
more suitable and convenient. In such cases, the
amount of vertical divergence below the horizon
forms an important element in the question, because
it is absolutely necessary that the mariner should
keep sight of the lights even when he is very near
them 5 while there is not the same call for a very
powerful beam which exists in the case of sea-lights.
Yet, even in narrow seas, where low towers, corre-
sponding to the extent of the range of the light, are
adopted, but where it is at the same time needful to
illuminate the whole, or the greater part of the hori-
zon, the use of dioptric instruments will be found
almost unavoidable, especially in fixed lights, as well
from their equalizing the distribution of the light in
every azimuth, as from their much greater economy
in situations where a large annual expenditure would
often be disproportionate to the ‘revenue at disposal.
In such places, where certain peculiarities of the
situation require the combination of a light equally
diffused over the greater portion of the horizon, along
with a greater vertical divergence in certain azimuths
than dioptric' instruments afl’ord, I have found it
.convenient and economical to add to the fixed re-
fracting apparatus a single paraholoidal reflector in
order to produce the desired effect, instead of adapt-
ing the whole to the more expensive plan for the sake
of meeting the wants of a single narrow sector of its
range. In other cases, where the whole horizon is to
be illuminated and great vertical divergence is at. the
same time desirable, a slight elevation of the burner,
at the expense, no doubt, of a small loss of hght, is
sometimes resorted to, and is found to produce, with
good effect, the requisite depression of the emergent
rays.” _
The oxyhydrogen, or lime light, and the Voltaic
light from carbon points, have, on account of their
intensity, been proposed for the purposes of the light—
house. ' There is, however, considerable uncertainty

in the exhibition of those lights, to say nothing of the
danger of entrusting so explosive a mixture as oxygen
and hydrogen to the care of the light-keepers. But
there are other objections; the smallness of the
flame renders them wholly inapplicable to dioptric
instruments, which require a great body of flame to
produce a degree of divergence sufficient to render
the duration of the flash in revolving lights long
enough to answer the purpose of the mariner. This
defect also applies to these lights when used with
the reflector, for a fixed light. The bude light, pro-
duced by combining a current of oxygen with the
flame of oil, has not been found to answer in practice.
Ooal gas has been occasionally used in lighthouses,
it being conveyed in tubes to the burners, and it has
its advantages in dioptric lights: it would of course
be difficult of application in the catoptric system,
especially the revolving, but the risk of an explosion
ought at all times to exclude this gas as a source of
,light to these important establishments.
In some cases it is found necessary to cut off on a
given bearing the beam proceeding from a lighthouse,
as a guide to the seamen to avoid some shoal, or as
a hint to put about and seek the opposite side of a
channel. This is sometimes done by placing a board
on the outside of the light-room; or by distributing
the reflectors round the concave side of the lantern,
towards the land: the latter arrangement, however, is
inapplicable when the illuminated sector exceeds the
dark one.
The term double lag/its properly applies only to
lights on different levels. They are used for the sake
of distinction from other lights, and are most
effective when placed in the same tower, and when
the lower lantern is arranged in the form of a
gallery, around the outside of the tower. Leading
lair/Ms are lights in different towers, and their use is
to indicate to the seamen a given line of direction,
such as the central part of a narrow channel, by their
being seen in one line; and the alternate opening of
the lights on either side of their conjunction serves to
indicate the proper moment for changing the tack.
In other situations the line of conjunction serves as
a cross-bearing to warn the mariner of his approach
to some danger, or to indicate his having passed it,
and thus to assure him of his entry in wider sea
room.
The construction of the lighthouse lantern is a
point of importance. A common defect is the ver-
tical direction of the astragals, which thus intercept
the light in the azimuth which they subtend. Mr.
Stevenson has adopted a diagonal arrangement,
Fig. 1350, as being better adapted for equahzing the
effect of the light, and giving greater stiffness and
strength to the frame-work, which is formed of gun-
metal, the dome being of copper. The use of these
metals avoids the necessity of painting. A lantern
for a light of the first order, 12 feet in diameter, and
with glass frames 10 feet high, costs about 1,2601.
On the level of the top of the lower panes is a narrow
gangway, for the keeper to stand on, in order to
cleanse and wash the upper panes, an operation which,
LLGHTHOUSE—LLLME.
189
in snowy weather, must sometimes be ‘frequently re-
peated during the night.1 At the top of the second
Cowl for l L) Ventilation-
&
l

_—J


W m
. /
L—*:~\/\_r\~_fjfj/
Fig. 1350.


LANTERN FOR FIRST ORDER OF LIGHTS.
panes hand-rings are fastened for the security of the
keepers in stormy weather. A light trap-ladder is
also attached to the outside of the lantern, for afford-
ing access to the ventilator in the dome. PW is the
parapet wall.
The lantern is liable to injury in high winds, or the
glass may be broken by large sea-birds coming against
it in a stormy night, or by small stones violently driven
against it by the wind. Framed plates called storm-
panes are kept in reserve to take the place of a
broken pane.
The Northern lighthouses are each under the
charge of at least two light-keepers, whose duties are
to cleanse and prepare the apparatus, to mount guard
singly after the light is exhibited, and to relieve each
other at stated hours, fixed by the printed regulations
and instructions under which they act. No keeper
on watch is allowed to quit the light-room until re-
lieved by his comrade; and means ‘are afforded for
making signals by air~tubes or otherwise from the
light-room to the sleeping apartments below. In such
situations as the Bell Rock, four keepers are provided
for one lighthouse, one being always ashore on leave
with his family, and the other three at the lighthouse.
At all the land-lighthouses the services of an occa-
sional keeper are engaged, who receives pay only
while actually employed at the lighthouse. Where the
situation allows of it, it is desirable to have the
keeper’s rooms in a building adjoining the light-
tower, to avoid dust, which is so injurious to the

(1) At some of the lighthouses of the Mediterranean, the lan-
tern is at certain seasons so completely covered with moths as to
obscure the light, and to require the attendance of men with
brooms. The Editor Was informed by the keepers at the Eddy-
stone, that bees and other insects were much attracted by the
light, and collected round the lantern in great numbers: larks
and other birds flew against it, and becoming stunned with the
blow, were picked up on the balcony, and were cooked by the men
for breakfast.

delicate apparatus and machinery in the light-room.
Covered ash-pits are likewise provided at all the
dwelling houses, to prevent the dust of the fire-
places from being carried by the wind to the light-
room; and iron floors are used in the lighthouses
instead of stone, which is often liable to abrasion.
The greatest cleanliness is enforced in all that
belongs to the lighthouse, especially to the light~room.
The lenses and reflectors are carefully freed from
dust before being washed or burnished, or they might
be scratched in the cleaning. The reflectors are bur-
nished with prepared rouge (tritoxide of iron),
applied with soft chamois-skin ; but the best method
of keeping the reflectors clean, is by a long rubbing
every day with a dry soft skin without rouge. Spirit
of wine is used for cleansing the lenses and glass
mirrors, a linen cloth being used for applying it, and
a soft dry linen rubber for drying the glass, which is
finally rubbed with a fine chamois-skin.
At the entrance of some of the great estuaries of
Great Britain and Ireland, the erection of lighthouses
being impossible, on account of the sand-banks being
too soft to sustain a solid structure, and the water
too deep to allow of the erection of a screw-pile light-
house, floatz'ng liq/its are established. The light-—
vessels of the Trinity House (of which there are
twenty-six on the coast of England) are moored with
chain-cables of 1% inch diameter, and a single mush-
room anchor, of 32 cwt. The lanterns are octagonal
in form, 5% feet in diameter; and where fixed lights
are exhibited, they are fitted with eight Argand lamps,
each in the focus of a parabolic reflector, 12 inches
in diameter. In revolving lights only four lamps and
reflectors are used.
We cannot conclude this notice without expressing
our obligations to Mr. Alan Stevenson for the very
kind manner in which he has placed his labours at
our disposal.
of the Bell Rock lighthouse, the founder of the
Skerryvore, is not only eminent as a lighthouse en~
gineer, but also as a lighthouse optician. To him are
we indebted for a complete elucidation of the two
methods of illuminating lighthouses; and should the
reader be tempted by the abstracts and quotations
which we have made from Mr. Stevenson’s works to
inquire further into the subject, we cordially refer
him to the “ Rudimentary Treatise on the History,
Construction, and Illumination of Lighthouses,”
published in 1850, in Weale’s Rudimentary Series.
LIGHTNING. See ELECTRICITY.
LIGNITE. See GOAL.
LIME. Sir Humphry Davy discovered in 1808
that when moistened lime was rendered electro-nega-
tive in contact with mercury, an amalgam was formed,
which by distillation yielded a white metal, the basis
of lime. He named it Calcium, from calm, the Latin
for lime. Its symbol is Ca, and its combining weight
20. When this metal is exposed to the air and gently
heated, it burns and produces oxide of calcium, or
lime, CaO. ‘
The usual source of lime is one of the carbonates.
By exposing powdered white marble, or Iceland spar,
The worthy successor to the Architect-
190 '
: LIME.
to a white heat for an hour in an open crucible, lime
may be obtained of tolerable purity; but to obtain it
quite pure, white marble is dissolved in dilute hydro-
chloric acid, a little caustic ammonia added, and the
solution filtered: carbonate of ammonia is next added,
and the precipitate washed, dried, and exposed to a
white heat in an open vessel. In a close vessel the
decomposition of carbonate of lime is so imperfect
that a red heat continued for many hours is insufficient
to expel the carbonic acid. Bncholz found that on
strongly heating five or six pounds of pure chalk
closely pressed into a crucible, it was converted into
a hard, foliated, yellowish mass, retaining nearly all
its carbonic acid: it was semitransparent from the
efl’ect of incipient fusion. Sir James Hall had pre—
viously found that by exposing powdered chalk to
great heat and pressure, it was fused without the
escape of carbonic acid: in this way he supposes
marble to have-been formed by a natural process.
Pure lime is white, or pale grey; it is acrid and
caustic, and has a powerful alkaline reaction. Its
density varies from 23 to 308: it is dilficult of
fusion, but promotes the fusion of some other oxides
in a remarkable manner, and hence its use as a flux.
When heated in the flame of the oxyhydrogen blow-
pipe it becomes highly luminous, forming what is
called the Drummoud light, and under this intense
heat it slowly volatilizes, and covers the interior of
the roof of the lantern with a sublimate of lime. It
is an important ingredient in mortar and other cements
[see MORTAR], and in its caustic state it is in certain
cases a valuable manure. When exposed to the at-
mosphere it first absorbs moisture and then carbonic
acid, and becomes partly converted into carbonate of
lime. When kept perfectly dry it does not absorb
carbonic acid. Its powerful affinity for moisture
renders it valuable for drying gases, and abstracting
water from alcohol and some other liquids. Diffused
through water it forms cream, or mill: of lime. When
lime is wetted with water a portion of the water
combines chemically with it, while another portion
passes off in vapour, and if quickly slaked in large
heaps, the temperature rises to above 500°, with the
evolution of light in a dark place: wood has been
scorched in this way, and lime barges have been set on
fire. The maximum temperature is produced when the
lime is mixed with about half its weight of water.
Before the water is added the lime is called quiet,
and after that addition sla/ced. It enlarges consider-
ably in volume by the operation. This sla/ced lime is
a true hydrate CaO,HC, and may be obtained in
imperfect six-sided crystals by placing lime water
under the receiver of an air~pump, with another vessel
containing ‘sulphuric acid to absorb the vapour as fast
as it is formed. Lime is, to a small extent, soluble
in water. At a temperature of 60°, 7 50 parts of
water are required for the solution of one part of
lime: by increasing the temperature less lime is
dissolved, so that at 212°,‘ 1280 parts of water are
required for the solution of one part of lime; while
by diminishing the temperature the solvent power of
water is increased; for at 32° only 656 parts of

water are required for the solution of one part of
lime. Lime water is limpid and colourless; its taste
nauseous and alkaline, and its alkaline reaction very
decided. It powerfully reddens turmeric, and changes
the blue of violets and cabbage to green. It is used
in medicine as an antacid. It is easily prepared by
pouring warm water upon powdered lime, and when
the mixture has cooled in a close vessel and subsided,
the clear part is decanted off. Exposed to the air, a
pellicle of carbonate of lime forms upon its surface,
which, if broken, is succeeded by another pellicle,
until the whole of the lime is separated from the
solution in the form of an insoluble carbonate.
Calcium, or its oxide, forms numerous compounds
with other bodies, only a few of which can be noticed
here. Chloride of calcium, or muriate of lime, CaCl,
is found in sea-water, and in some mineral waters.
It may be formed by heating lime in chlorine, when
oxygen is evolved equal in volume to half that of the
chlorine absorbed. It may also be formed by the
action of hydrochloric acid on carbonate of lime,
evaporating to dryness, and exposing the residue to
a red. heat in a close vessel. It has a strong attraction
for water, and soon deliquesces by exposure to the
air; hence its use in drying gases, and in depriving
alcohol, ether, and other liquids of water by distilling
them off dry chloride of calcium. One part of water
at 60° dissolves four parts of the chloride; at 212°,
water dissolves it readily: it is also very soluble in
alcohol. It becomes phosphorescent by fusion, form-
ing what is called Homherg’s phosphorus.
Chloride of lime or hleachiug powder is noticed
under BLEACHING.
Calcium forms compounds with Iodine, Bromine,
and Fluorine. The native fluoride 0]" calcium is noticed
under FLUOR—SPAR.
Nitrate of lime, CaO,N()5, is a deliquescent salt
soluble in one-fourth its weight of water at 60°. It
is sometimes found in spring water, in old plaster,
and in artificial nitre-beds. [See Pornsn]
Calcium forms with sulphur a number of compounds,
such as the sulphuret, CaS, the hisulphurct, CaSZ, and
others. Hyposulphite of’ lime, CaC, S202, is abun-
dantly produced from the refuse lime of the gas-
works. After having been removed from the purifier
and exposed to the air for a few days until it ceases
to smell of sulphuretted hydrogen, the hyposulphite
may be dissolved out by an equal weight of cold
water, and crystallized after evaporation at 120° ; or
by means of carbonate of soda it may be converted
into hyposulphite of soda. The lime“ salt is used for
removing the salts of silver from photogenic drawings,
so as to render them permanent when exposed to
light. '[See Pnoroennrnx]
Sulphite of lime, CaC,S02, and hpposulphite of lime,
CaO,S2()5, are of no importance in the arts, but
sulphate of lime, Ca0,S03, under its various names
of seleuite, alabaster, gypsum, plaster-stoue, &c., is a
compound of firstrate importance in the arts. [See
GYPSUM] It may be formed artificially by dropping
sulphuric acid upon lime, or by decomposing a solution
of chloride of calcium, or any of the soluble salts of
LIME.
191
lime, by sulphuric acid or by a soluble sulphate.
The sp. gr. of artificial anhydrous sulphate of lime
is 2927 : it requires about 500 parts of water at 60°,
and 450 parts at 212°, for its solution: but according
to Berzelius it is equally soluble in hot or cold water.
Most spring and river waters contain traces of this
salt, and in harel waters it is often abundant, render-
ing them slightly nauseous and unfit for washing and
for culinary purposes. It resembles other sulphuric
salts in slowly decomposing when the solution is
subject to the action of decaying vegetable matter,
in which case the odour of sulphuretted hydrogen
is evident. It is also decomposed by the alkaline
carbonates.
Phosphurel of Calcium, Ca]?, is formed by passing
the vapour of phosphorus over lime, heated to a dull
redness, under which circumstances the oxygen of
the lime converts a portion of the phosphorus into
phosphoric acid, and the evolved calcium combines
with another portion of phosphorus to form phos-
phuret of calcium. It is a dull brown compound;
when thrown into water it rapidly decomposes a por~
tion of it with the evolution of phosphuretted
hydrogen gas, the bubbles of which, escaping at the
surface, ignite by coming in contact with the oxygen
of the air. Hypophosphz'le of lime, CaO,PO,2HO,
and phosphz'te of lime, are not of importance; but the
phosphates, of which there are several, are very much
so. The common phosphate of'lz'me, lrz'hasz'ephosphale,
or hone-phosphate, occurs abundantly in bone-ash, and
is also found with fluoride of calcium in apalz'z‘e and
uwrom'le. A solution of bone-earth in hydrochloric or
nitric acid, is boiled to expel the carbonic acid; and
precipitated by caustic ammonia, the pure bone phos~
phate separates as a bulky precipitate, which forms in
drying a white amorphous mass, and consists of three
equivalents of lime, or 5384 per cent, and one equi-
valent of phosphoric acid, or 41616 per cent. It
occurs native in apatite and moroxite, as already
noticed ; these phosphoresce when heated; and it also
occurs in phosphorz'le and asparagus stone. Its pri—
mitive form is a six-sided prism. Crystallized apatite
is found in great beauty in Cornwall and Devon.
Coprolz'les abound in phosphate of lime; they appear
to be the excrements of fossil reptiles, and resemble
in external form oblong pebbles, from 2 to 41 inches
in length, and 1 or 2 in diameter; but they vary in
size with the calibre of the intestines which produced
them: their usual colour is ash-grey interspersed
with black; their texture resembles indurated clay;
they have a conchoidal and glossy fracture, and the
scales, and occasionally the teeth and bones of fishes,
are irregularly dispersed through them. They are
abundant on the shore at Lyme Regis, in the has of
the estuary of the Severn, and in the gault of Surrey ;
but they occur throughout the lias of England, and
in strata of all ages that contain the remains of car-
nivorous reptiles. Attempts have been made to use
these nodules in the production of phosphorus, and
also as a manure; they contain from 55 to 70 per
cent. of bone phosphate. Some varieties of chalk
contain small quantities of phosphate of lime; it is

found in some schistous and other rocks; it is present
in all fertile soils, and in the vegetables which they
produce, and in this way it is conveyed into the
animals which feed upon them. Graham has detected
in the water of the deep wells of London minute
quantities of phosphate of lime and phosphate of iron;
he was induced to look for it from the rapid growth
of confervae, and thinks it probable that the superiority
of certain waters for irrigation may depend upon the
presence of phosphoric acid. The other phosphates
of lime need not detain us here.
The most abundant compound of lime is the ear-
houale, CaO,G()2. It is found in spring and river,
and consequently in sea-water. It is an essential
ingredient in all fertile soils, and it occurs in every
kind of rock. The primitive form of crystallized
carbonate of lime, or calcareous spar, is an obtuse
rhomboid, and its secondary forms are more numerous
than those of any other substance, as many as 680
modifications having been described and figured.
Ieelaurl spar is extremely pure carbonate of lime in
its primitive form ; it is doubly refractive when trans-
parent, but some of the varieties are opaque or trans-
lucent, snow-white or tinged with difierent colours;
its fracture is foliated and rhomboidal; it is scratched
by fiuor-spar; it ‘dissolves with effervescence in
hydrochloric acid, and the solution, much diluted,
gives a white precipitate with oxalate of ammonia.
Syrup of sugar dissolves hydrate of lime, and crystals
of the carbonate may be thus obtained, .by boiling
1 part hydrate of lime, 3 of sugar, and 6 of water,
filtering and exposing to air for a couple of weeks.
The lime is deposited in acute rhombic crystals.
Pure water does not dissolve any sensible quantity of
carbonate of lime; but water containing carbonic
acid takes up a notable quantity. On this account
the waters of many natural sources contain car-
bonate of lime, and when by exposure to air carbonic
acid escapes, the carbonate of lime separates, and
forms upon solid substances, near, or placed there for
the purpose, calcareous incrustations, often of consi-
derable size: the pelré/fuz'ug-well at Matlock owes its
peculiar properties to this cause. Calcareous slalae-
tiles and slalagmz'les are produced from a similar cause
in some of the caverns of Derbyshire and elsewhere.
The waters traversing crevices in the rocks fall in
drops from the vault of the cavern; but each drop
before falling remains suspended for a time, during
which, a portion of its carbonic acid escapes, and a
minute portion of its carbonate of lime is left behind.
It also deposits another minute portion of calcareous
matter on the spot upon which it falls, and as the
drops are formed nearly in the same spot for years
together, a calcareous incrustation is thus produced,
hanging downwards from the roof, and slowly in-
creasing in size by the action of successive drops.
In this way a stalactite is formed (manage, I drop).
Immediately below this incrustation another is formed,
and in this way a stalagmite is formed (Malay/pd, a
clrop); and in process of time the two incrustations
unite, and form a continuous column. See Fig. 1351.
Satin-spar is a fibrous variety of carbonate of lime.
192
LiuJs-meunun-meuonicn.
Am'agonz'le, originally from Arragon in Spain, often
occurs in six-
\ sidedcrystals,
< ZZZ/i. of a reddish
' if colour, and
~. harder than
the common
carbonate. An
acicularor fi-
brous variety
-is found in
France and
1?
1.


Germany: jlos
w _' ' fem'l is re-
Fig. 1351.- STALACTITES 8: srnnacmrrns. garded as be-
longing to the same species. Some varieties contain
about 3 per cent. of 'strontia.
The various calcareous rocks which are met with
among all the sedimentary deposits, often form strata
of enormous thickness, and afford carbonate of lime
of various degrees of compactness, and many of these
contain fossil remains of great extent, variety, and
beauty. The numerous varieties of marble and lime-
stone consist essentially of carbonate of lime. [See
MARBLE] There are many varieties of the inferior
limestone, such as common mar/ole, bituminous lime-
slone, also called swine-stone or slink-stone, from its
peculiar smell when rubbed: oolz'le or v'oeslone, a
é'ommon building stone at Bath; and its variety,
Porllancl stone.- Pz'solz'le or pea-stone, consisting of
small rounded masses in concentric layers with a
grain of sand in the centre; and lastly, anal/i: and marl.
All these stones are used for ornamental or useful
purposes; in building, in agriculture, and in the for-
mation of mortars and cements. The subject of
lime-burning will be-treated of in the article MORTAR.
The shells of molluscous and other animals, the egg-
shells of birds, the hard casing of the lobster and crab,
are formed of carbonate of lime ahnost pure: the
bones of animals also contain a considerable quantity
of it.
The general characters of the salts of lime are
as follows :-—those which are soluble in water are
not precipitated by pure ammonia, but potash and
soda throw down hydrate of lime, and the carbonates
of potash, soda and ammonia produce precipitates of
carbonate of lime. Oxalate of ammonia produces in
their solutions a white precipitate of oxalate of lime
soluble in nitric and hydrochloric acids. This test is
extremely delicate. The soluble sulphates throw
down sulphate of lime. Those salts of lime which
are soluble in alcohol, tinge the edge of its flame of a


reddish colour; and those salts which are insoluble
in water are decomposed by boiling with carbonate of
potash, and afl’ord carbonate of lime ; they are usually
soluble in nitric and hydrochloric acids.
LIME-KILN. See Monrnn. .
LIME-STONE. See LIME—MARBLE.—INTBO-
nuoronr Essar, p. lxxxiii.
LINE. A line is defined by Euclid as “ length
without breadt .”
LINE. Before the metrical system was adopted in

France, the inch was divided into 12 lines, and the
line into 12 points. We sometimes see the English
inch divided into lines. The French line is ‘0888 of
an English inch, and also 2%- millimetres.
LINEN. See FLAX—WEAVING.
LINSEED OIL. See OILS.
LIQUATION. See ELIQUATION—ASSAYING. Also
Inrnonuoronr ESSAY, p. xcii, where a liquation
- furnace is represented.
LIQUEUR, the French name for a liquor com-
pounded of alcohol, water, sugar and some aromatic
substance. The number of liqueurs is very great:
they are sometimes named after the inventor.
LIQUID. See ConnsronflAnnnsionfll-Irnnoa
srnrros and Hrnnanmos.
LIQULDAMBAB. (from liqnz'rlnm, fluid, and amber,
the Arabic name of amber), a balsam obtained from the
Liqnz'clambm' Slyracgflna, a tree growing in Mexico,
Louisiana, and Virginia. See BALSAMS.
' LIQUORICE. An extract prepared from the root
or nln'zomn 1 of the Glycy/rln'zn glaom, a native of
Germany, but cultivated in some parts of Britain.
The extract is chiefly prepared in Spain, and is im-
ported under the name of Spanish juice, or liquorice.
The rhizoma is taken up at the age of 3 years. It
is often several feet in length and about half an inch
thick. It has a faint odour and a sweet mawkish
taste: if the bark be chewed it becomes in a short
time acrid, from the presence of a resin. On evapo-
rating a strong infusion to a small bulk, and adding
sulphuric acid, a precipitate falls containing sugar and.
albumen: this is washed with water acidulated with
sulphuric acid, then with pure water, and afterwards
digested in alcohol, which separates the album en. A
solution of carbonate of potash is then dropped into
the alcoholic solution until the acid is neutralized.
It is filtered and evaporated, and a yellow transparent
mass of lz'gnom'ce sugar (Glycyr/tz'zine) is thus obtained.
It is intensely sweet, uncrystallizable and easily
soluble in alcohol and in water: it combines with
acids, bases, and salts. Its composition is expressed
by 016 H12 012-
The rhizoma by infusion in warm water or macera-
tionin cold, affords a mucilaginous fluid which is bland
and demulcent. The powdered root is used to pre-
vent recently made pills from adhering. The extract is
formed into rolls 6 or 8 inches long, which are dried
and wrapped in bay leaves to prevent them from
adhering. 100 lbs. of the dried root aflord 30 lbs. of
extract. Starch or peasmeal is usually added in
making up the rolls, the object being to prevent them
from melting, which they have a tendency to do in‘
warm weather. The rolls should be black, dry, and
in cold weather break easily with a shining fracture,
Liquorice, when pure, dissolves entirely in the mouth.
Crude liquorice not only contains starch or meal, but
also copper or brass derived from the Pans used in
boiling down the infusion: hence the necessity fort
refining, an operation which is performed by melting
the rolls in water, draining ofl the Solution SO as to
leave sand and other impurities behind, inspissating

(I) A long creeping subterraneous stem, from ,sz'gwna, a root.
Lrrnrc AClli-LOCK.
193
it and forming it into more slender cylinders, sugar or
gum Arabic being added to produce hardness. In
Yorkshire the extract is prepared in the form of small
cakes or wafers, named Poaleflaci calico. Liquorice
is used as a demulcent to allay tickling cough.
LITHARGE. See LEAD.
LITHIC ACID, also called Uric acid and Uri/lie
acid. It was discovered by Scheele in urinary calculi,
whence the term lithic acid (from hides, a sioac). It
has been found in the urine of animals, in guano, in
the coprolites or fossil excrement of Ichthyosauri, in
the excrement of snakes, &c. It is a soft, white,
crystalline powder, almost insoluble in cold water.
It forms salts with bases. Its formula is C10 H4 ()6 N4.
LITHIUM, a metal,‘ (L 7) the oxide of which
was discovered by Arfwedson in 1817, and called
lil/iia, from M609,- a stone, from its ‘occurring only in
the" mineral kingdom. It was first found in peialiie
and spodamiac, minerals found in the iron mine of
Uto, in Sweden, and it has since been found in amt/y-
goaiie and lejoidolile, in some varieties of mica, and in
green loarmaliae. Davy obtained the metal from its
oxide by the action of voltaic electricity; it resembled
sodium in its whiteness, but it combined so ‘eagerly
with oxygen, that its properties could not be ex-
amined. The oxide is earthy or alkaline in its cha-
racter: it' is white, very caustic, and saturates acids
readily, and forms neutral salts with them. It-
attracts moisture and carbonic acid by exposure to
air, and has a.very_ strong aflinity for water. It has
a remarkable corrosive action upon platinum.
LITHOGRAPHY. . See Enenfiine. .
LITMUS, a blue fugitive colour prepared from a
lichen (Lccaaora iarlarea) growing in the Canary and
Cape Verd Islands. The dye is prepared in Holland
by a process similar to that used in the preparation
of Archil and Cudbear. [See ARCHIL] The ground
lichens are first treated with urine containing a little
potash, and left to ferment, whereby a purple-red is
produced. The coloured liquor treated with quick-
lime and more urine, is again left to ferment for two
or three weeks : it is then mixed with chalk or gypsum
into a paste, formed into small cubical lumps, and
dried vin the shade.
The colouring matter of litmus has been named
eryl/iriae, crylliayliac, and erg/llzric acid, and is closely
related to lecaizoriac (C18 H8 08 + H0) existing in
different species of lecaaora. It is soluble in water
and in spirits of wine, and was formerly used as the
colouring matter for 'tinging the spirit in thermometer
tubes; but being liable to fade, it is no longer used
for that purpose. -Nollet found that the coloured
spirit bleached by exposure to light, resumed its
colour 011 breaking the tube; this occurred several
times in succession. Litmus is used for staining
marble : the colour sinks deep, but it renders the
marble somewhat more brittle,
Litmus is used by the chemist as a test for detect-V
ing the presence of acids, which turn it red. The
blue colour is restored by alkalies, so that when
slightly reddened, it may also be employed to detect
alkalies. For these purposes, it ‘may be employed as
voL. II.

a tincture, or paper stained blue, with an aqueous
solution, may be used.1 The paper-should be bibulou s,
in strips, and not sized, so that fluid-dropped upon it
may be instantly absorbed. “ The litmus solution
should be poured into a dish or soup-plate, and the
paper should be drawn through it piece by piece in
such a manner that‘ ‘the fluid may be in contact with
both sides, and then having been held to drain a few
seconds, it should‘ be hung on lines of thread or
twine to dryin a convenient place. No fumes of
acid or burning charcoal should have access to it, for
they injure the colour; and as soon as the’ paper is
dry, it should be taken down and‘ laid together. The
tint ought to be a full blue, or if light, not faint or
undecided. It may be judged of by touching a piece
of the paper with a very weak acid, and observing
whether the red colour produced is vivid, and a strong
contrast to the blue tint of the rest of the paper.
If the solution should have been made so dilute as to
produce too weak a tint, the paper may be dipped a
second time, but this is to be avoided if possible, as
it involves a second exposure to the air.” When the
paper is dry, it should be packed in a case to preserve
it from light and air; the former destroys its colour,
and the carbonic acid and other substances in air
injure it, and even change it to red. C
The solution of vlitmus is- sometimes improperly,
called iiaciare of iamsolc, a name which was given to:
the'colour, in order to keep its true source a secret.' '
Lac/mas is the'German term for litmus.
LIXIVIATION, the process‘ of ‘separating a
soluble from an insoluble body by washing. It is'
described under Dncocrron. ' » '
' LIXIVIUM, a term used by the older ~chemists to
signify a solution of an alkali in water: it is synony-
mous with ley. ‘
LOADSTONE, a term applied to the magnetic‘
iron ore, or natural magnet, from an early observation
of its most useful directive property by various
nations. Thus the; Chinese term it. lcfia-c/iy, or the
directing-stone. In Sweden it is named segel-siein, or
the seeing-stone. In Icelandic leiderslcia, or the
leading-stone, from the Saxon lcedaii to lead, whence
the English name load or lodesioae. ,So also the term‘
lodeszfar or guiding-star, is applied to the star of the
pole, and the term lode to the leading vein in a mine. '
LOAM, a native clay mixed with quartz, sand, and
iron-ochre, and sometimes with carbonate of lime.
LOCK, an instrument for securing a door, drawers,
box or desk cover, &c., by means of an interior coll’
which cannot or ought not to be capable of being
moved, except by the application of a lacy or lever,
applied to it from without. In some locks, however,
the bolt is moved‘ or skoi' by the action of a spring,
and can be drawn back by means of a handle attached
to the inner side of the lock, or by a key applied on’
the outside. Such are called spring-locks or late/i-
loclcs. Some locks are furnished with a couple of
bolts, one of which is moved by a key and the other
by a spring and handle. Others have two or more

(1) Minute directions for the preparation and use of test papers
are given by Dr. Faraday in his “ Chemical Manipulation.”
O
194
LOCK. -
bolts, which are shot xby the‘action of the key alone.
Locks also differ in form and size, and in the arrange-
ment of their parts, to adapt them to the almost
endless purposes to which they are applicable. In
locks of the same size ‘and constructed by the same
maker on the same principle, the interior arrangements
must be so varied that one key may not openinore
than one look. Door and closet locks are attached
to the inner surface of the door, 'or they are inserted
into a mortice out in the thickness of the wood, and
the bolt is shot into a fixed socket. In some kinds
of box ‘and cabinet locks the bolt is shot into or
through a staple, which drops into the lock on
shutting the lid or cover, to which the staple is
attached.- The bolts are in some cases of a hooked
shape, and are projected by a lateral movement into
cavities prepared for them. Padlocks are detached
locks, in which one end of a curved bar of iron moves
on a pivot on one side of the lock, and is secured by
the bolt passing through a staple at the other end of
the curved bar.
_ In the most common variety of locks the principle
of security is the insertion of wheels or wards, so
arranged as to prevent the entrance or revolution of
any lever ‘or key which is not formed with corre-
sponding openings so as to thread its way among them.
The wards ‘ are usually segments of circles arranged
concentrically: they are ‘ commonly formed of thin
sheet iron riveted to the plates of the lock, or for
damp situations they are of sheet copper to prevent
rust. The better kind of, warded locks have what
are called soZz'aZ' wards: they are thicker than the
ordinary ones, and are formed by casting in brass, and
finishing in the lathe.
ll,“ Fig. 1352 represents a
' l l portion of the interior of
' a common lock ; tithe
! shaded part is the back


0
plate with two wards
t attached to it: the key
is also shown upon the
central pin secured to
the plate. Now it is
evident that the notches in the key must be so
formed as to allow the projecting wards to pass
freely into them, or the key could not turn round so
as to shoot the bolt, and that a false key, not pro-
Fig. 135?.
~vided with notches of the same dimensions, and
the same distance apart, could not under ordinary
circumstances open such a lock. Wards are some-
times what are called L-sfiaped, T-s/mjaed and Z-slzaped,
from the resemblance of their vertical sections to
those letters. The keys to looks so fitted must of
course be ‘cut to correspond to them.
A key is so-familiar an object that it scarcely
requires description; yet there are many points con-
nected with it which deserve to be stated. The key
consists of a cylindrical shank with a loop-shaped‘
handle at one end, and apiece called the an or‘ wet
projecting from ‘it at or near the other. Locks which
are entered from one side only have the keys with
hollow shanks forthe purpose of fitting the central

pin; but in looks which open on either side there can
be no such pin, and consequently the keys have solid
shanks, (See Fig. 1354!, No. 8,) and for the purpose
of steadying the key the shank is prolonged beyond
the bit,_ so as to enter and turn in a socket in the upper
part of the key-hole of that plate of the lock which
is furthest from the person using the key. The bit
having been introduced into the body of the look by
a narrow opening or key-kale, is turned round within
the look by a rotatory motion’ imparted to the shank
until it comes in contact with a part of the bolt, so
shaped that the bit of the key cannot pass it to com-
plete its revolution without shooting the bolt either
backwards or forwards. The bits- and consequently
the key-holes are variously shaped, in order to prevent
the introduction of a false key. In Fig. 1353, the
hits a b e d are all of difierent shapes ; e and f resemble


Fig. 1353.
a, but the portions cut away allow the key-hole to be
so contracted in those parts as to prevent the inser-
tion of another key not so indented.
There is, however, one great defect in warded locks,
which belongs to the very principle of their construc-
tion, namely, that a key may be perfectly efficient
and» yet not thread the various mazes of the wards. -
The keys Nos. 1, 2, 3, in Fig. 1354, are of very different -
pattern; the first of the three has two plain or simple

Fig. 1354.
wards; the second two L-wards, and the third a‘
T-ward between two plain wards, and it is true that
not one of these three keys could be substituted for
the other in opening the locks to which they respec
tively belong; but unfortunately the only eflicient
part in these keys and in keys of a far more compli~
cated pattern, is the extremity of the bit shown in
the fourth or slreletorz-lrey, which will effectually open
such locks as the first three keys are intended for, _
without touching the wards. The lock is made a
little more secure by attaching wards to the front as
well, as to the back plate of the lock, in which case
LOCK.
19:5»:
the key must be furnished with corresponding notches,
as in No. 5. This is the key to a solid warded look,
but it is evident that a simple pick similar to No. 12
would open such a lock. Indeed the theory of master-
heys is founded upon defects in the construction of
locks such as weare now- noticing. For example,
the wards of the locks represented by the three keys
Nos. 9, 10, and 11 are so far different from each other
that ‘one of the three keys could not be substituted
for another, and yet the fourth or master-hey, No. 12,
would open all three, and indeed a whole suit of locks
constructed on the same principle. A celebrated
London lock-maker states that his keys. “ are made
in series, having a separate and different key to each,
and a master-key for opening any number that may
be required. So extensive are the combinations, that
it would be quite practicable to make locks for all the
doors .of all the houses in London, with a distinct
and different key for each lock, and yet that there
should be one master-key to pass the whole.” No. 6
represents a very good form of wards, and No. 7, a
still better form; but keys of this kind are necessarily
very weak, and a little rough. usage, and often ordinary
wear and tear, will cause such keys to bend or break.
A key of a complicated pattern does not, however,
always imply a complex arrangement of wards; for
the bits of many keys have more notches than there
are wards to be threaded; and thousands ffof locks
are manufactured every year with no wards at all,
although the keys which accompany such locks ar
out so as to represent very intricate wards.
It will " be seen that all the keys hitherto figured,
except No. 8, are pipe-keys, adapted to such looks
as have a central pin, and consequently can be opened
on one side only, and in such cases, it is evidently of
little consequence whether the wards be arranged
symmetrically or not. But the key No. 8 will open
the look from either side, and is symmetrical, or rather
it may be regarded as two keys separated by the
central opening in the bit, so that in opening the
door on one side the upper half only threads the
wards, and in opening the door on the other side the
lower half threads the wards. In such a case, the
wards on one plate are exact counterparts of' those
on the other plate, or there is a central plate adapted
to the central opening‘ of the key, and on either side
of this plate the wards are arranged. ,
_ The form and position of the wards of an ordinary
lock may be easily detected by the common artifice of
the burglar, as in the warded lock represented in Fig.
1355, which, according to Mr. Chubb,1 was once on
the door of the strong-room of a London banking
house. The wards of the lock will be seen concentric
with the central pin. a is the key with the cuts in
the web exactly corresponding to the wards in the
lock. 6 is a burglar’s instrument made of tin, with
a composition of wax and yellow soap on one side of

(1) “ On the Construction of Locks and Keys, by John Chubb,
Assoc. Inst. C. E. Excerpt Minutes of Proceedings of the Insti-
tution of Civil Engineers.” 1850. The original lock, key, and
picklocks were exhibited to the meeting, and also a few picks
selected from about a ton weight of such instruments captured
by the police, and deposited in Scotland Yard.

the bit,'so that when inserted'into the key-hole a pen.
fect impression .of the wards is taken. Now we
have alreadygseen that, in order to make a pick-lock,
all that is necessary is to preserve the end of the web
é'z'r
' .2:
g,
Q
luring
Fig. 1355.
which moves the bolt; this is accomplished by the
instrument a, which is made so as to escape the
wards, and will open or shut the look as well as the
original key. Even so rude a pick-lock as at, by pass-
ing round the wards, has been known to open such a
lock with the greatest ease.
The second principle of security in looks is the
introduction of tumblers. A tumbler is a sort of
sprz'up-lateh, which detains the bolt of the look so as
to prevent its motion, until the key in turning first
lifts the tumbler out of contact with the bolt, before
moving it.
. It is remarkable, that the security offered by tum-
blers is much more ancient than that by wards.
Denon, in the celebrated French work on Egypt,
represents a lock in common use in Egypt and Turkey
at the present day, and its great antiquity is proved
by the fact of its being sculptured among the has-
reliefs ‘in the temple of Karnak. The construction
of this look will be understood from the following
figures: aa is the case screwed to the door; 6 h is







i
all 1 ' ‘I
it r 5 will
1 I’ ~—~ :Hq'il'
_Q ‘iiill'i‘ I];
.1» $91M»









i in
llllllli



L-za-



.'_-._ a,
' -_ .Fz'g. 1359.
Fag. 1356 . '
. . the bolt. In the
m . W .§
0‘ case above the
bolt are a num-


uaa/a/a/a
/ ber of small
cells containing
‘\“~\ “‘ a *~ headed ins ar-
(6 p. ’
.. ranged in any
. I‘ ‘l R desired form.
Fig. 1357.
In the top of
the bolt a number of holes are similarly arranged, so
that when brought into the right position, the ends
of the headed pins may drop into the corresponding
holes in the bolt, in which state the bolt is fastened.
To unlock it, a large hollow or cavity is made at the
o 2
19'6-
LUCK. '
exposed ‘end of the bolt which extends under ‘the
holes occupied ‘by the pins. The key consists of’
a piece ‘of wood, Figs. 135.8, 1359, ‘having pins
arranged like those in the lock, and as" long as'the-
thickness of the bolt above the cavity. When, there-
fore, the. key is introduced and pressed upwards, its
pins exactly fill the holes in the bolt, and of course
dislodge those which had fallen from the upper part
of the case. The bolt may consequently be drawn as
in Fig. 1357,1eaving the headed pins elevated in their
cells instead of occupying the position shown by the
dotted lines, in Fig. 1356. In Fig. 1357,-the key is
shown in its ‘place, diminishing, therefore, the apparent
size". of the “cavity inthe bolt, which of course must
be high enough to receive thekey and its pins before
the latter are lifted into ‘the holes.
The Egyptian lock is rather widely distributed. It
has been in common use from time immemorial in
Cornwall and the Fagoj Islands, to which places it. was
probably: taken by the Phoenicians. A similar lock is.
in use in the Highlands of Scotland, and the locks and
keys ‘of metal found in British towns occupied bythe
Romans were'probably Celtic. " .Locks were found in
Hercul'aiieum of great apparent complexity. The
earliest notice of locks is in the Odyssey (xxi) where
it is stated, that‘ Penelope wanting to open a wardrobe
took ‘a‘brass key, very crooked, hafted with ivory.
Before the invention of locks and keys, or in places
where they were unknown, doors were fastened with
knots according to fancy, and the secret of untying‘
them was carefully-preserved by the owner.
The ,leller-loc/l or combination padlock, is described
in a book printed at Amsterdam in 1682. It can be
easily picked. Some locks have an alarum attached
to them, such as a large bell, a species of fire-arm,
as, so’ that an attempt to violate the lock would
cause great noise and confusion. These and various
other contrivances .aremore-curious than useful, and
may be passed over here. ' ‘I i i v ‘ _
The principle of security indicated by the above
arrangement ‘was not known in Europe till it was
re-invented by Mr. Barron, and applied by him in
conjunction with wards,'in. the construction of a lock
which was patented in 177 ‘The same principle was
adopted by Mr. Bramah about ten years later, but the
use of wards or obstacles to the key was dispensed
with. In the Egyptian lock, the number and position
of ,therimpediments afford security; in Bramah’s lock
security depends on the various degrees of motion
which the'several impediments require before the bolt
can be'mpved.
Figs. 1360 and 1361 will show at a glance the
difference‘ fbetween a warded and a tumbler lock,
and :the me'ansby which in either case the bolt
is kept ‘steadily in the position in which it is left
by the ,key. 1360 represents what is called a
finals-spring locki thebolt l is represented as being
llfllf 8505.01‘. half'lockea; and can be moved either
backwards or 'forwardsbylthe action of the bit of the -
key withinthe large cavity of the bolt. At the top-
of the bolt is, a spring s,‘ formed by cutting a strip
of ‘metal from the' bolt‘ itself, and’ bending it so that
‘the edge. Thus the ac-

its upward ‘pressure causes'the bolt to press upon
the edge‘~ of the rim. 'W hen entirely locked or un“
lock-ed, one of the notches, nor n’, falls into the
edge of - the rim and holds the bolt: when half
looked, as in the figure, .
the convex’surfac‘e between
the two notches rests upon
tion ‘of the spring s is to _
hold the bolt pretty firmly _
in its place as left by the -
key; but there: is this ‘
serious defect to this look, '
that the bolt can be
moved backwards or for!
wards simply by ‘applying
pressure to either end of
it, so that except for the
moral purposes of a lock,
this one is of little or no
use. Indeed, if the reader examines the question more
closely than we intend to do in this article, he will be
forced to admit that a look, even by one of the first!
rate makers, is in most cases rather a moral than a
physical security. Every one, except the thief, who
finds‘ a door or a receptacle locked,‘ is reminded by‘
that circumstance that the owner wishes no one to
open or gain entrance thereto. If the dexterous thief
could only get to the lock of the iron safe, he would:
be able, in most cases, to pick it with ease; if he


Fig. 136].
.could get to the cash-box, he would carry it off with-
out stopping to pick it. The stories that are told of
skilful thieves having been baffled by the locks - of such‘
or such a maker, belong to a past era. The thieves
have, within the last year or two, graduated higher
in theirart, and it behoves the lock-makers to follow
their: example. The fact is, that we trust more to our
bolts than to our locks; we trust to the integrity of
our servants, the watchfulness of our police, and the
local ignorance of the thief.
A common tumbler lock is shown in Fig. 1361. It
will be seen that, instead of the spring attached to
‘the' bolt, as in Fig. 1360, this bolt is furnished with
.'two notches n n’ in its upper edge. Behind the bolt 6
is the spring-latch or tumbler 2', moving on a pivot at“
one end, and'presse'ddown by the action of a spring on‘
‘its upper edge. The portion of the tumbler concealed
by the bolt 'is represented by the dotted‘ line. At the
upper angle of the tumbler is fixed a projecting stud,
or slump s, which, when the bolt is fully shot, falls
into the notch n, and holds it, until by the application
of the key, the 'bitofwhichtouches the lower edge of
the tumbler, the stump is raised out of the notch, the
bolt is "then released,’ and can be ‘shot further for-
ward‘ until the notch n’ comes under the stump,
which' falls in'and secures the bolt. Hence it will be
evident that, whether the bolt be shot or unshot, no
pressureaapplied to its extremity will move it.
' Thus it will be seen that the two principles of
security in looks, viz. mamls and lnmolezs, which may be
applied separately or combined, are intended to perform
;the same office. ‘Wards are fixed obstructions,-—tum-
LOCK.
~19?
blers ‘are movable ones; and their ‘office is t'o'prevent
the introduction of other instruments than the proper
key. One of the most celebrated forms of tumbler
lock is Mr. Chubb’s, shown in Fig. 1362. It consists

»~—- H.117
It . _ . _ w






, . .._-j
.I l
.
. i i
- _ law .






Fig.1362. cnUBB’s DETECTOR LOCK.
of 6 separate and distinct double acting tumblers,
with the addition of a dclcclor, by which if, in an
attempt to pick or open the look by a false key, any
one of the tumblers be lifted too high, such an at-
tempt is discovered on the next application of the
true key. The principal parts of this look are repre-
sented in Fig. 1362.. .c is the bolt into which is
riveted the stump s; lure the tumblers, 6 in num-
ber, moving on the centre pin a ,- they are placed one
over the other, but perfectly separate and distinct,
so as to allow of their being elevated
to different heights. d. is a divided
spring, forming 6 separate springs
pressing upon the ends of the 6 tum-
blers. e is the detector-spring ; and it
will be noticed that the back tumbler
has a projecting piece’ near the detec-
tor-spring, with a stud or pin p fixed
into it. Fig. 1363 is the key. Now
it is evident that all the tumblers
must be lifted to the exact heights
required, to allow. the stump s to pass
through the longitudinal slits of the tumblers, so that
the bolt may be withdrawn. There. are no ordinary
means of ascertaining when any one tumbler is lifted
too high or not high enough, and it. is still more
difficult to ascertain the combination of the six.
Should a false key be inserted, and any one of the
tumblers be raised beyond its proper position, the
detector-spring 6 will catch the back tumbler, and
retain it, so as to prevent the bolt from passing, ‘and
upon the next application of the true key, notice will
be given of a tumbler having been overlifted in the
attempt to pick the lock, as the true key will not at
once unlock it; but by turning the key the reverse
way, as in looking, the tumblers will be brought to
their proper bearing, allowing the bolt to move
forward, and the stump to enter the notches a’. The
bevelled part of the bolt will then lift up the detector-
spring, and allow the back tumbler to fall into its
place. The lock being now restored to its original
position, may be opened and shut in the ordinary
manner. Although the pin p is attached to the back


tumbler only, yet as'it ‘extends across all the Joth'ers,
should any one be raised too high, it would elevate
this pin sufficiently to catch into the detector-spring,
in which case the detector would have to be relieved
before any further attempt to pick the lock could be
successful. Referring to the key, Fig. 1363, it may
be stated as a general rule, that in looks of this con-
struction, the lowest step, or that next to the end of
the key, operates upon the bolt; the other steps move
the tumblers to the exact height necessary for the
stumpto pass. It is evident, that by varying the
length of these steps almost endless varieties of lock
will be produced.
But, perhaps, the lock which has excited most
attention, admiration, and inquiry in this. country, is
that by Bramah, which during many years maintained
its reputation. Many a mechanical genius has stood
with admiring gaze before the shoplwindow'in Picca-
dilly, and read the challenge appended. to the pattern
lock, ofl’ering a reward of 200- guineas to any artist
who could construct an instrument capable of picking-
it; and the difliculty of the attempt will, we think,
be best appreciated by the reader’s making himself
master of the details of the lock, which we now
proceed to give.
In a pamphlet published by Mr. Bramah,1 a simple
illustration of the principle of his look is given, which
we will repeat before describing the lock itself. In
Fig. 13641,]; is a bolt capable under certain conditions
of being moved backwards and forwards in the rect—
angular frame F F. In this belt are cut 6 notches,
into which. are exactly fitted the 6 slides a b c d e f,
and .it will be evident, that in the present position of
these slides, the bolt is incapable of moving. These
slides admit of an up and down motion in the notches
of the bolt B, and they are moreover furnished



Militia" while‘ his mlllllllll if
Fig. 1364.
with notches, 1, 2, 3, 45, 5, 6. Now, if by any means
the slides could be raised, so that all their notches
should coincide with the bolt, it is clear that in such

(1) This pamphlet is now scarce, but Mr. Hobbs has favoured us
with the loan‘of his copy. It is entitled, “ A Dissertation on the
Construction of Locks; containing, Fina—Reasons and obser-
vations, demonstrating all looks which depend on fixed wards to
be erroneous in principle, and defective in security. Secondly,-~
A specification of a new and infallible principle, which, possessing
m the properties essential to security, will be a certain protection
(as far as a lock is concerned) against thieves of all descriptions.
By Joseph Bramah, Engineer.” Second Edition, London, 1815.
198
LOCK;
case, the bolt could be moved’backwards and forwards.
Now, this elevation of the slides may be accomplished
by means of a tally T, which on being pressed against
Nllillll
I ‘5,1
lllll
_ “ mlxlilngipnmnnmmmmmunnnmmu mllltllmmllimmlpmmmnmnmmumuiumupmmmmmmumlL
Fig. 1365. nnAmAn's LOCK.
. the lower extremities of the vslides, will raise them
»,~;.§1ai1ll unequally, but nevertheless, so as to bring their
notches into one horizontal line, and thus allow. the
bolt to pass. Supposing that only the lower ends of
the slides are exposed to
view, it is evident that
.in the absence of such a
key or tally, it would be
ditlicult, if not impossi-
ble, to ascertain how far
to press in the sliders,
so as to allow the bolt
to pass. This simple
illustration will assist
the reader in under-
standing the details of
the lock itself.
Fig. 1365 shows the
_ outside of one of Bra-
mah’s looks as adapted
to a desk or box. Figs.
1366, 1367, 1368, 1369
give the details. A A,
' . 1365 shows the
bolt. It is formed like
two hooks rising out of
a bar of metal, which
slides backwards and
forwards upon
the surface of H" i
the plate B B, 8
the edge of
which is turn-
ed up at right
angles, and Fz'g.1367.
. I has openings
through‘ it for the hooked parts of the bolt to move
in. The bolt is guided in its motion endways by
slidingthrough square holes in the edge pieces of the
lock, which'are riveted to the main plate. A plate
of metal 0,, is secured to the edge pieces by two
screws 1, 1, and two steady pins. This plate prevents
the bolt from rising up out of its place, and has a
cylindrical projection 1) on its-surface, which contains


Fig. 1366.
all the mechanism of the lock, and protects it from,


i the bolt backwards
‘ without the proper

external injury.‘ The projection D is neatly finished, '
and when the lock is put on a desk or box, its end
projects through the wood a small distance, forming
a. very neat escutcheon, having the key-hole in its
centre. Fig. 1366 shows a perspective view of the
mechanism of the lock withdrawn from its case 1).
It consists of- a barrel or cylinder E pierced with a
cylindrical hole: through its centre. The inside of the
hole has 6 narrow grooves cut through its length,
and in the direction of. radii, from the centre towards
the outside bythe cylinder E, but leaving a sufficient
strength all round. These grooves are fitted with
small sliders of the form shown at a a, Fig. 1367,
,1‘ being split in thickness, and forced into the grooves, so
as to move up and down therein with a slight friction,
that they may not fall down by their own weight.
They have small notches 2, 3, 3, cut in the back part,
the use of which will be hereafter explained. The
lower part of the opening through the cylinder n, is
closed by a circular plate of metal 1‘, Fig. 1366, fixed‘
by two screws. It has a pin 6, projecting up from its
surface, which forms the centre for the pipe of the-
key to slide over. There is also another short circular
stud c, on its under side, which enters into the
curved opening a3, in a part of the bolt at Fig. 1368.
The stud e revolves with its plate 11, and the‘
cylinder E; and by
the form of the
opening cZ, moves


and forwards. it






now remains to . .._‘ _
show how the cy-
linder E is pre- ____________ __ .
venteg from.I being tuine roun , so as a
to move the bolt Fig. 1368.
key ‘being introduced. The cylinder has a circular
groove or notch cut round its circumference at ee,
to such a depth as to intersect the straight radii or
grooves some distance, but still leaving a ring of
metal round the
hole through E, or







‘it would ran into a x3 number of pieces. U \
‘Into the notch e e a
thln circular plate j g g j‘ ' i _ ._
of metal, in the form \\\\\\ \' of f f, Fig. 1366, is r 3%: r .1:
introduced, having 3’ fttfittttatt .-
hole through its :
centre, the same size Fig. 1369. '
as the bottom of ‘the notch. It is. divided into two
halves to enable it to go round the cylinder, as seen
at fy”, Fig. 1369, and dotted in Fig. 1366, and when
the ‘mechanism of the lock is introduced into the
case 1), the plate ff is held fast, and secured by
two screws, 4 4: (Figs. 1365 and 1369) to the‘ plate 0,
in which situation the cylinder E with its appendages
can be turned round by’ its key, but cannot move up
ordown, the plateff preventing it. We shall now
LOOK.
199
proceed to explain how'the key operates to turn the
cylinder is and move the bolt AA. The plate fj;
Fig. 1366, has 6 notches, 5, 5, 5, &c., filed round the
inside. Through these notches the sliders a a can
move ‘up and down when the plate is in its place;
but cannot move round with the cylinder n in a
circle, unless the sliders are all depressed in their
grooves, so that the deep notches 2, Fig. 1369, of all the
6 sliders come into the plane of the circular plate f f,
as shown by the section Fig. 1369, in which state the
cylinder with its sliders may be turned round in order
to shoot the bolt. Now if any one or more of the
sliders are pressed too low, or are not_long enough, to
come into the plane of ff; the cylinder cannot be
moved round, because they are intercepted by the
edges 'of the notches 5, 5. In the plate f f the whole
number of sliders is pressed up, or caused to rise
in their grooves, as far ‘as the top of the cylinder n,
by a spiral spring 6, coiled loosely round the pin 5,
Fig. 1366. This forces up a small collet, 7, on which
the steps 8 of the sliders a a, Fig. 1367, rest. The first
looks were made with a separate and independent
spring to each slider, but it is a very great improve-
ment, the introduction of one common spring to raise
up the whole number; because if a person attempts to
pick the look by depressing the sliders separately by
means of any small pointed instruments, and by chance
brings two or more of them to the proper depth for
turning round, should he press any one too low he
has no means of raising it again without relieving the
spring 6, which immediately throws the whole number
of sliders up to the top, and destroys all that had been
done towards picking the lock. Another improve-
ment of ’ this look, and one which very much increased
the difliculty of picking, and its consequent security,
was the introduction of two false and deceptive
notches cut in the sliders as seen at 3, 3, Fig. 1367. It
was found that in the attempt to pick this look, an
instrument was introduced by the key-hole to force
the cylinder 1: round. At the same time that the
sliders were depressed by separate instruments, those
sliders which were not at the proper level for moving
round were held fast by the notches 5, 5, in the plate
ff hearing against their sides, but when pressed
down to the proper level, or till the notch 2 came
opposite f j; they were not held fast, but were relieved.
This furnished the depredator with the means _ of
ascertaining which sliders were pressed low enough,
or to the point for unlocking. The two notches 3, 3,
in the sliders are sometimes cut above the true notch
2, sometimes below, and at other times on each side,
and are not of sufficient depth to allow the cylinder
n to turn round, but only to mislead any one who
attempts to pick, by his not knowing whether it is
the true lock or otherwise, or even whether the slider
be higher or lower than the true notch.
Another recommendation of Bramah’s lock, is the
smallness of the key, which can be carried about the
person of the owner without inconvenience. The
form of the key is shown at 10, Fig. 1366. It has 6
notches out round its edge of different depths, to
press the slider down each a proper quantity. It

has also -'a small ‘projection from its side," which
enters the notch 1) (Fig. 1366), in the cylinder n to
turn it round, and throw the bolt. The‘ bolt of this
look is prevented from being forced back when ‘locked
by the stud ‘c on the bottom F of the cylinder, Fig.
1366, coming into a direct line with its centre of
motion, as shown at c, F ig.‘1368, when no force, how-
ever great, applied to drive the bolt’ back, would have
any ‘tendency to turn the cylinder 12 round. This
prevents the mechanism from being injured, though it
is very delicate. These locks are sometimes made
with'eight or more sliders. -
The patents which have been taken out at various
times for real or pretended improvements in looks,
are very numerous.- Mr. Chubb has collected a list
of English ‘patents granted between the year's 1'77 41
and 1849, and they amount to 84 in number. It
would be useless to give an analysis of these patents,
since, with the exception of Bramah’s, Barron’s,
Chubb’s, and a‘ few others, they mostly consist of
variations in the form and arrangement of -the'
tumblers, slides, &c., and in very many cases without
any apparent reason. It will be useful, however, by
way of recapitulation, to refer to the collection of
locks now in the possession of Mr. Hobbs, exhibited
by Mr. C. Aubin of Wolverhampton. It attracted-
little or no attention during the Exhibition, and it is
not even alluded to in the Jury Reports, and yet this
collection may fairly be pronounced as of first-rate
value, of great historical interest, and showing in the
arrangement considerable mechanical ‘skill. It is
entered in the Illustrated Catalogue thus :—-“ Speci-
mens to illustrate the rise and progress of the art of
making locks‘, containing at different movements, by
the most celebrated inventors in the lock trade.”
The specimens are arranged round a central axis, upon
a series of circular disks like a dumb-waiter, and the
axis is terminated at the top with a Bramah lock and
key. The whole series is so connected, that on turn-
ing the key at the top, the bolts of all the locks are
shot or unshot at pleasure.
the order in which they are arranged, but we will
nevertheless adopt it. i
No. 1 is called a Roman loch. It consists of a
simple bolt with a binder spring, for holding the bolt
in any position in which it is placed until a suificient'
force is applied to overcome it. Thousands of locks
‘are made on this principle, which has been already
illustrated in Fig. 1360.
No. 2 is a French loch: it is the. same as No. 1,
with the simple addition of a friction roller.
No. 3 is marked Ancient. It is a bolt lock, and
was found in an ancient building: it is an improve-
ment on Nos; 1 and 2, as the bolt requires, before it
can be shot, to be pressed down, in order to release it
from a catch at the back end of the bolt.
No. 4:, also marked Ancient, is a single-acting tumbler
lock. By single acting is meant one that cannot-
be raised too high in order to release the bolt.
Fig. 1361 explain this.
on the contrary, must be raised to the exact height
to allow the stump to pass. See Fig. 1362.
We do not approve of '
Double-acting tumblers, '
200
LOCK.
No. 5. An Ancient Engl'ls/z loan, with a- double—
aelz'ng lameler, or one in which the tumbler, as just
explained, must be raised to the exact height required,
to allow the stump of the bolt to‘ pass the gating or
gateway of the tumbler.
No. 6. Modern English. This is a single'acting
tumbler. _ ‘ _ ,
No. 7-. By Mace. Double-acting. '
No. 8. Saenmeaforel'e ‘first. A double-acting clraw
tumbler; that is, a tumbler which draws down instead
of beinglifted as, in most'tumbler locks.
No. 9. Indian. Single-acting tumbler with~ pin.
, No. 10.‘. Tlzompso'n,‘ 1,805. The first look with more
'than one jtumblen, This lock has two tumblers, one
single and the other" doubleactingn
N o.’ 11. Daniels. Single-acting tumbler, differing
only in form from those previously used :—a remark
that will apply to‘ a large number of subsequent
patentees.
‘No. 12, Wallon. No. 13, Barron’s first patent,
1-7 7 4.‘. No. 14:, Bic/hereon. No. 15, Dalen. No. 16,
Dace, sen. No. 17, Sanders, 1839, a double-acting
tumbler lock with four tumblers. No.18, Cornl/zwaz'zfe,
17 89,. (No. 17, patented in 1839, is the same in form
and action as No. 18, patented in 1789. This remark
Will apply with more or less force until we come to
N o. 4L0: we shall therefore only give the names and
dates.) No. 19, Richards & Peers. No. 20, Summer~
ford’s second. No. 21, Rowntree, 1790. No.22, Duce,
first 1823. No. 23, Parson’s first, 1832. No.
ea, Bickerton’s. No. 25, Price, 17 7 4.‘. No. 26, Aubin,
1830. In this look a revolving curtain is introduced
for the purpose of closing the key-hole during the
revolution of the key. This same invention has been
claimed in a patent, enrolled during the present year,
_No. 27,‘ Barron’s second, 177 41. No. 28,
Bird’s, 1790. No. 29, Duce, jun. second, 18412.
No. 30, Ruxton’s, 1818. No. 31, Chubb’s simplified,
1834. No. 32, Marr. No. 33, Tann, 18413. No.
341, Hunter, 1833. No.35, Parson’s second, 1833.
No. 36, Young, 1830. No. 37, Lawton, 1815. No.
38, Strutt, 1819. No. 39, Scott, 1815. No. 40,
Chubb’s first, 1818. This is the original detector lock ;
and we may here state that whatever merit belongs
to the detector lock is due to Mr. Chubb, senior.
No. 411, Parson’s third, 1833. This is the first
changeable lock patented in- England. The elevation
of the tumblers is regulated by an adjusting screw
passing through the lock to the inside of the door.
' ‘his. screw changes the positive, but not the relative
position of .thc tumblers; so that the same difference
in the steps of the key must be retained, the change
being made ‘only in the length of the bit, The num-
vher/of changes for each lock is consequently very
limited; .ina lock of ordinary construction from 15
to 20 distinct, keys. can be applied. No. 42, Pierce,
18%0. This lock is constructed on a plan suggested
by the ~Marquis of Worcester in his “ Century of
Inventions :27—116 says, “ A look may be so con-
structed that if a stranger attempt to open it, it,
catches his hand as, a trap catches the fox; though
far from mlaiming him for life, yet marketh him so

that if once suspected he might‘ easily be detected.”
In this look a steel barb or sharp arrow-head is con-
cealed below the key-hole, and if any person in
attempting to open the lock should overlil't a tumbler,
the barb would be thrown oil? by a spring into his
hand. - It is said that the patentee himself experienced
the efficacy of this invention, by receiving the barb
into his own hand. No. as, Ruxton’s, 1816. This
lock is furnished with a tell-tale, so that if the
tumbler be overlifted, by attempting to pick the look,
a pin or catch is thrown out from the lock, and would
be seen on unlocking the lock with the right ‘key. '
Its action is similar to Chubb’s detector, patented
two years later, but the latter is much more simple
and effective in its operation. Patents for detectors
since the date of Chubb’s first, are numerous: they
all differ in form, and may be said to be equally
effective ; but they are alilce in principle, and cannot
be said to add much if any thing to the security of
the look. No. 44., Bramah, '17 84.‘. No. 415, Russell.
No. 416, Mordan. The last two are repetitions of
Bramah.
Although the Bramah lock differs completely in
form from the tumbler lock, its principle of action is
precisely the same. In the tumbler look, there are a
series of spring latches or tumblers, each of which
has to be raised to a certain position, to allow a pin
or stump fixed to the bolt to pass. In the Bramah
look, there are a series of slides, each of which has to
be pressed down to a certain position so as to pass
the locking plate before~ the bolt can be moved.
The question, whether such locks can be picked,
was discussed with great zeal and earnestness during
the Great Exhibition, when Mr. Hobbs, an American
mechanician, accepted the challenge which had stood
so many years in Mr. Bramah’s_shop window. It
will be sufficient for our present purpose, to give the
Report of the Committee appointed to see fair play
between the parties. It is dated, 2d September,
1851 .:--—~ ' -
“ Whereas for many years past a padlock has been exhibited in
the window of Messrs. Bramah’s shop, in Piccadilly, to which was
appended a label, with these words:—-‘ The artist who can make
an instrument that will pick or open this lock, will' receive two
hundred guineas the moment it is produced;’ and Mr. Hobbs, of
America, having obtained permission from the Messrs. Bramah to
make a trial of his skill in opening the said lock, Messrs. Bramah
and Mr. Hobbs severally agreed that Mr. George Rennie, F.R.S.,
London, and Professor Cowper, of King’s College, London, and
Dr. Black, of Kentucky, should be the arbitrators between the
said parties; that the trial‘should be conducted according to the
rules laid down by the arbitrators, and the award of two hundred
guineas decided by them on undertaking‘ that they should see fair
play between the parties. - On the 23d July, it was agreed that
the lock should be enclosed ,in a block of wood, and-screwed to a
door, and the screws sealed, the key-hole and hasp only being
accessible to Mr. Hobbs; and when he was not operating, the key-
hole to ‘be covered‘with a band of iron, and sealed by Mr. Hobbs;
that no other person should ‘have access to the keyhole. The key
was also scaled up, and not to be used till Mr. Hobbs had finished
his operations. If‘Mr. Hobbs succeeded in picking or opening the‘
lock, the key was to be tried; and if it locked and unlocked ‘the
padlock, it should ‘be considered a proof that Mr. Hobbs had not
injured the lock, but picked and opened, it, and was entitled to the
two hundred guineas. On the same day, July 23, Messrs. Bramah
gave notice to Mr. Hobbs that the look was ready for his opera-
tions. On July2é, Mr. Hobbs commenced his operations; and on
August 23, Mr. Hobbs exhibited the lock open to Dr. Black and
LOCK.
'201
Professor‘ Cowper, Mr. Rennie being ‘out 'of town; Dr. Black‘
and Professor Cowper then called in Mr. Edward Bramah, and
Mr. Bazalgette, and showed them the lock open. They then
'wichdrew, and Mr. Hobbs locked and unlocked the padlock in the
presence of Dr. Black and Professor Cowper. Between July 24
and August 23, Mr. Hobbs’ operations were for a time suspended,
'So that the number of days occupied by him were sixteen, and the
number of hours spent by him in the room with the lock was
fifty-one. On Friday, August 29, Mr. Hobbs again locked and
unlocked'the padlock in the presence of Mr. George Rennie,
:Professor Cowper, Dr. Black, Mr. Edward Bramah, Mr. Bazalgette,
and Mr. Abrahart. On Saturday, August 30, the key was tried,
and the padlock was locked and unlocked with the key by Pro-
,fessor Cowper, Mr. Rennie, and Mr. Gilbertson, thus proving that
Mr. Hobbs had fairly opened the look without injuring it.
Mr. Hbbbs then formally produced the instruments with which
,he had opened the look. We are, therefore, unanimously of
opinion, that Messrs. Bramah have given Mr. Hobbs a fair
opportunity of trying his skill, and that Mr. Hobbs has fairly
picked or opened the lock, and we award that Messrs. Bramah
and Co. do now pay to Mr. Hobbs the two hundred guineas.”
Messrs. Bramah complied with this decision, but
they objected to it on the ground that their chal-
lenge required that an instrument, i. e. only one
instrument, should be used in picking or opening
their lock ; whereas Mr. Hobbs used three instru-
ments, viz. a fork for pressing down the disc, a bit of
steel for turning the cylinder, and a small stiletto for
adjusting the slides. Whatever merit there may be
in this objection, it does not affect the question as to
the violability of all looks constructed with slides or
tumblers known and in common use in this country,
up to the date of the Great Exhibition, when the
United States Department of that grand institution
may be said to have introduced a new era into the
art of lock-making in this country. We are not, for
obvious reasons, going to initiate the reader into the
art of picking locks, and we are inclined to agree with
the Report of the Jury, Class XXII, in doubting
“whether the circumstance that a lock has been
picked~ under conditions which ordinarily could
scarcely ever, if at all, be obtained, can be assumed
as a test of its insecurity.” But, on the other hand,
it is fair to add, that, after a long and careful inves-
tigation of the merits of a vast number of ‘locks, we
are strongly inclined to agree with the position
assumed by Mr. Hobbs, “that wherever the parts of
a lock, which come in contact with the key, are
affected-by any pressure applied to the bolt, that look
can be picked.” The time in which this can be done
will evidently depend on the skill and experience of
the operator. To illustrate this principle would be
to explain how to pick most of the locks in ordinary
use, which it may be prudent not to do. That lock-
makers have tacitly admitted the truth of this propo-
sition, is evident from the introduction of false
notches,_.wards, rings,‘and curtains, in and about the
key-holes. If the above proposition be true, it is
evident that, in constructing a lock which shall not
be. capable of being picked, an entirely difierent prin-
ciple must be adopted. This has been done, and we
now proceed to explain the construction of a cheap
lock patented and manufactured by Mr. Hobbs, which
we believe, in the present state of the art .of lock-
picking, cannot be picked. _ i D
This lock, in its general appearance, resembles the
q
serving as an additional security

usual tumbler locks : it has the same form of key and
the same moveable parts, the only ad‘dition' being
attached to the miracle?‘ stump, which addition works
under the bolt of the lock. Fig. 1370 represents the
mechanism of this look; 5 6 is the bolt; it, the
tumblers, with the usual slots or gatings, through




Fig. 1370. nonns’s PROTECTOR LOCK.
which a tumbler stump, 8, must necessarily pass when
the bolt is being locked or unlocked. In all other
locks this stamp is riveted into the bolt, consequently
any pressure being applied, or an attempt made to
withdraw the bolt, brings the stamp against the face
of the tumblers, causing them to bind, by which
means the gatings are easily found. In this look,
on the contrary, the stump s is riveted into a piece
shown detached in Fig. 1371 ; the
hole it, fitting on a centre or pin in a
recess, formed at the back of the bolt,
and the stump, passing through a slot
in the bolt, stands in its usual posi-
tion; and there is a small binding
spring to prevent the piece from turning of itself.
When the key is applied to the lock, and the tumblers
properly adjusted, the stump, meeting with no obstruc-
tion, passes through the gating of the tumbleré; but
should an attempt be made to withdraw the bolt before
the tumblers are all properly raised, the stump, meeting
with the slightest resistance, turns the piece to which
it is attached on its centre, and raises the portion
of the piece 39 so that it comes into contact with a
stud rivetedinto the case of the lock, thereby pre-
venting the possibility of withdrawing the bolt; at
the same time releasing the tumblers from any pres-
sure, so that it is impossible to ascertain their
proper position. (Z is a dog, or lever,
catching into the top of the bolt, .‘\


against its being forced back; it is
the “ drill-pin,” on which the key,
Fig. 1372, turns; "r is a piece on
which the tumblers rest. Although,
by this simple addition,‘ and without
adding materially to the cost, locks
are rendered perfectly'secure against
picking, or being ~opened by any in-
strument except the true key or its
duplicates; yet, as with all other
locks where the key is not suscep-
tible of change, any person having had the key
in his _- possession may, by taking an impression,
become master of the look. For purposes of abso—
lute security this danger is eifectually guarded,
against by the permeate-ding or changeable ftey locks;


Fig. L372.
202
.LO OK.
‘a notice of which will lead us‘ into some details'
States ofAmerica. ' . - - . ~- — - .
Twelve“ or' thirteen‘ years “ago, ' ‘the locksmiths: .of I
the Unitedi'States of--_'America'1did not: doubt the?
security of the best locks, such- as were in'common':
use in England: ' They believed them'to be proof Q
against all known’ means of picking or of" forming ‘aj
false key,.~l_iy anyikinowl'edge“ obtained by an inspection’;
through the keyhole ;..-it was thought desirable to '
secure themfagain'si't'the chance of, the true key being-
copied, and thus-flan opening effected. Accordingly, *
Mr. Andrew's," amcchanician ofilierthfimboy, 'in the
State of ,Néw-filersey, ‘endeavoured to'construct a
lock so that the party.‘ using it could change-its form
at pleasure. His lock wassiinilar. to that of Ohubb,
having a_ series of tumblers and a‘ ‘ detector; but
‘before placing the lock on the‘door, 'the- purchaser
could arrange’ the tumblers" in‘ any way‘ as 'the
combination suited‘ his‘ convenience; the key being
made with a series of moveable bits, which could be
arranged in a corresponding combination with the
tumblers. In order to make a change in the look
without taking it ‘from the door, each tumbler was
so constructed that in the act of looking it could be
raised or drawn out with the bolt- A series of rings
was furnished with the key, corresponding with the
thickness of the moveable bits of the key; and any
one, or as many more of the bits could be removed
from the key, and rings substituted. These bits
being removed, and the rings taking their place, the
corresponding tumblers would not be raised by the
turning of the key, and consequently would be
drawn out with the bolt, becoming in fact a portion
ofthe bolt itself. Therefore, when a bit was removed,
and a ring substituted, so much of the security of
the look was lost as depended on the tumbler that
was not raised; consequently, a lock having twelve
tumblers being locked with a key with alternate bits
and rings, would evidently become a six-tumbler
lock 5 but should a tumbler that‘ was drawn out with
the bolt be raised in the attempt to pick or unlock
it, or should any one of the acting tumblers be
raised too high, the detector would be thrown, and
prevent the withdrawing or unlocking of the bolt
until re—adjusted. This look was in great repute in
the United States, and was adopted by the principal"
banking establishments, and other large firms.‘_' The
success of this lock soon brought competitors into
the field. ~ . ‘
The most successful of these‘ was Mr.'Newell, of
Broadway, New York, who invented the Permutating
lock, composed of a series of first and secondary
tumblers, the secondary‘ series being operated upon
by the first series; Through the secondary series
was passed a screw, having a clamp overlapping the
tumblers on the- inside of the lock, each tumbler in
the series having an elongated slot‘ to allow the screw
to pass through. On the back of the lock 'was-a
small round key-hole, which the head of the screw
rested, forming as it were a receptacle for a small
secondary key ; so that when the large key gave the
respecting'thel progress of. loc-kém‘akingin the Unitedf

necessary form" to ‘the tumblers, the small key ‘was
applied-and. operated on the clamp-screw, clamping
I Sandi-"holding together.- the secondary series, and re-
=tainii1'g1 them iinfrelative heights or distances imparted
ftothe’m'by‘the large key '; the door was then closed,
and‘ the .bolt projected, and the first series of tumblers
fell‘ag'ain" to their original position. The objection
to 1 this‘. look is the necessity for a secondary key:
also, that should the clamp-‘screw be left unreleased,
the firstjseries of tumblers ‘would be held up by the
secondary series", and an exact impression of the
lengths .of the several bits of the key could be
obtained through the key-hole while the look was
unlocked. " a " ' ‘
To- obviate the necessityfor a secondary key, Mr.
Newell made a series of- notches on one of the
secondary tumblers, corresponding in distance with
the difference in the lengths‘ of the several bits of the
key. , (See'T2 iii Figs. 1, 2,'of the steel engraving.)
On turning the key each bit raises its plate or tumbler,
so that ‘some one of the notches presents itself in
front of the tooth zfon a dog or lever, LL. As the bolt
is projected, the tooth‘ being pressed into the several
notches, the secondary series are held in their position
by the tooth of this dog or lever, as shown in Fig.
2 of the steel engraving, instead of needing the
secondary key. In unlocking the lock the tooth is
again detached, the tumblers all fall into their original
position, and the lock again becomes a blank, as in
Fig. 1. These valuable additions to the detector and
tumbler lock were'made prior to the year 1841, but
no improvement in the actual safety of the lock
against picking had been hit upon. Mr. Newell
found, in the course of his studies, that it was
quite possible to pick bo.h Andrews’s lock and his
own, and that with a venggimple instrument. This
discovery he candidly made known, confessing that
his own look, as well as all others based on the
tumbler principle as then arranged, was‘l‘insecure.
To contrive a really secure lock was, therefore, the
aim of his further studies. First, a series of compli-
cated wards were added to the lock; but these proving
inefiectual, the notching of the abutting parts of the
first and-secondary series of tumblers, or of the
stump face, and the ends of the ‘tumblers, together
with a revolving curtain closing the key-hole, were
resorted""to.. Thus if a pressure were put upon the
bolt, the tumblers could not be successively raised
by the picking instrument in consequence of their
being held ~fast by these false notches. This look
was considered effectual, and for some time baffled
the skill of the country,— until an engineer, named
Pettis, accepted the challenge, and won the reward
of'five hundred dollars, offered by Messrs. Newell
'85 Day-to any one who should pick the lock. This
lockwas shown in the United States Department of
the Great Exhibition, and was very remarkable for its
_ beautiful workmanship.
These repeated‘ trials had proved that security
cannot be attained by adding difficulties, therefore Mr
Newell endeavoured to construct a lock in such a
manner that the obstruction to the withdrawing of

A'Ievah'fln .s-hrmny l/n' [iv/I unl'm-A'n/ and flu» .Illu-lllu/jr/ film/Mm’.
[Is/wim- 171111‘, and I 21W!‘ removal ‘
Fig. 1‘





I/ 2570/’ a’;
q llllm 71mm‘ X
Bolt looked, Demtorf’lau- marred, and {lie Auxiliary tumbler
in its plant.

LOCK.
.203
the bolt could not be ascertained through the key-hole.
In his Parautoptic1 lock he accordingly retained the
good points of the former locks, and sought to guard
against their defects. Fig. 1 of the steel engraving
represents the lock unlocked, with. the cover or
top-plate removed, also the auxiliary-tumbler and the
detector-plate are removed. Fig. 2 shows it locked,
with the cover and the detector-plate removed and
the auxiliary-tumbler in its place. Fig. 1373 is the
lock with the cover on, showing the detector-plate.
Fig. 3 of the steel engraving is the key; and Fig. 41
an end view of the key, showing the screw by
which the separate bits are fixed in the key. Fig. 5
shows the six bits of the key detached; and Fig. 6
shows the same key as Fig. 3, but having the bits
arranged in a difiierent succession, thus forming a
different key.
BB, in Figs. 1 and 2, is the bolt. r‘ are the
first series of moveable slides or tumblers; s, the
tumbler springs; T2, the secondary series of tumblers;
and T3, the third, or intermediate series between the
first and secondary series of tumblers. P]? are the
separating plates between the first series of tumblers,
8’ the springs for lifting the intermediate slides or
tumblers, to make them follow the first series when
they are lifted ‘by the key. On each of the secondary
tumblers, T2, is a series of notches, corresponding in
distance with the difference in the lengths of the
movable bits of the key : as the key is turned in the
lock to lock it, each bit raises its tumbler, so that
some one of these notches presents itself in front of
the tooth t on the dog or lever, L L. As the bolt B is
projected, it carries with it the secondary tumblers
T2, and presses the tooth 1,‘ into the notches, with-
drawing the/ tongues 45 from between the jaws, jj, of
the intermediate tumblers T3, and allowing the first
and intermediate tumblers to fall to their original
position; while the secondary tumblers r2 are held in
the position given to them by the key, by means of
the tooth 2f being pressed into the several notches, as
shown in Fig. 2. Should an attempt be made to
unlock the bolt with any but the true key, the tongues
d will abut against the jaws, jj, preventing the bolt
from being withdrawn; and should an attempt be
madeto ascertain which tumbler binds and requires
to be moved, the secondary tumbler, 012, that takes
the pressure (answering the same purpose as the
movable stump in the lock, Fig. 1370) being behind
the iron wall, 1 I’, which is fixed completely across
the lock, prevents the possibility of its being reached
through the key-hole, and the first tumblers, T , are
quite detached at the time, thereby making it impos-
sible to ascertain the position of the parts in the inner
chamber behind the wall I 1'. The portion I I of this
wall is fixed to the back plate‘ of the lock, and the
portion 1' to the cover. K is the drill-pin, on which
the key fits; and c is a revolving ring, or curtain,
which turns round with the key, and prevents the
possibility of inspecting the interior of the look
through the keyhole : and should this ring he turned
to bring the opening upwards, the detector-plate, D,

(I) That is, covered from_ sight.

(see Fig. 1373 ), is immediately carried over‘ the key-
hole by the motion of the pin 12’ upon the auxiliary
tumbler T4, which is lifted by the revolution of the
ring 0, thereby effectually closing the opening of the
key-hole. As an additional protection ‘the bolt is held
from being unlocked by the ‘stud 8 bearing against the

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Fig. 1373. nx'rnnron OF THE rananror'rrc LOCK.
plate 1); also the lever Z Z holds the bolt when locked
until it is released by the tail of the detector-plate cZ'
pressing the pin 12. Z’ is a lever, holding the bolt on
the upper side, when locked, until it is lifted by the
tumblers acting on the pin 19’. x x are separating.
plates between the intermediate tumblers T3; at u and
a’ u’ are the studs for preserving the parallel motion
of the different tumblers. '
The most remarkable feature of this look is, that it
changes itself to the key, so that in whatever way the
moveable bits on the key are arranged, the lock ane
swers to that form without moving any part of it from
the door. The purchaser of the lock can change the
arrangement of the key at pleasure. By altering the
numerical position of the bits in the key, the lock, in
fact, alters itself to any number of new looks equal to
the permutation of the number of bits on the key. If
a 6-bit key, the lock can be changed 720 times; if
7 bits, 5,040 times; if 8 bits, 40,320 times; if 9 bits,
362,880 times; if 10 bits, 3,628,800 times; and if
12 bits, 417 9,001,600 times. Two extra bits are sup-
plied with each key, which add very much to the
number of changes. As the key turns round, each bit
raises its tumbler to a point corresponding with its
length, imparting to the first and second series the
exact form of the key. The secondary series of
tumblers being carried out with the bolt, and the
tooth on the lever being pressed into the several
notches on the front face of the secondary series, holds
them in the position given them by the key, while the
other portions of the lock fall again to their original
position. In attempting to pick the lock, should a
pressure he put on the bolt to ascertain the obstruc-
tion, it will be readily seen that it will be brought to
bear on the third or intermediate tumblers. To pre-
vent the possibility of reaching these, there is a wall
of metal fixed across the lock, which confines the ope-
rator wholly to the key chamber. By detaching the
portion of the tumbler that takes the pressure given
to the bolt from the parts that can be reached through’
the key-hole, leaving that portion always at liberty,
2041
LOCK-QLOGWOOD.
the possibility of ascertaining what is wrong ~is cut
off, thereby throwing the whole security of the look-
into a chamber beyond the wall'of metal, which is
wholly inaccessible, and forming, as it were, another
look without a key-hole. ~
~ There is another source of insecurity that has still
to be provided against: when the tumblers can be
seen through the keyhole, if the underside of them
be previously prepared, so that the key may leave a
distinct mark the next time it is'used, showing where
it began to touch each tumbler‘ inlifting it, the exact
length of each bit of the key can be measured, and
a correct copy of the key be made. The possibility
of seeing the tumblers is here prevented by sur-
roundingv the inside of the key-hole with the ring
or revolving curtain, and when this curtain is
turned,_fto"bring the’, opening opposite the tumblers,
the keyti-hole is shut on the outside by the detector-
tumbler: Should the lock be charged with gun-
powder through the key-hole, for the purpose of
blowing it from the door, the plug in the back of the
key-chamber would yield to the force, leaving the
lock uninjured, the curtain protecting the interior.
LODE. See LoAnsroNE—~MININe.
. LOGWOOD. An important tree for dyeing pur-
poses, first discovered in the bays of Gampeachy and
Honduras, growing in the greatest luxuriance. It is
a member of the sub-order OmaZZJinew, which includes
Brazil-200961 or Bemcmzbuco-wo'od, Can't-wood, and other
dyes,'with'several esteemed fruits, as tamm'z'rzcls, the
seeds of the Carob or Locust-tree, 850.; also purgative
medicines, as semza, the whole‘ being comprised in the
vast order of Zegumz'nous, or pod-Marina plants.
' Logwood, or as' it was once called, bloat-wood
(Haezzazfoxy/Zam campeclzz'mmm), was first introduced
into England in the reign of Queen Elizabeth. It
was‘ found to yield a violet-coloured dye, and with
other ingredients, a black dye; but it was soon pro-
hibited by act of parliament, as afi'ording a “false and
,deceitful ” colour, alike injurious to the queen’s
subjects at home, and “ discreditable beyond seas to
our merchants and dyers'.” This prohibition was
strictly adhered to, so that wherever this valuable
‘dye was found, it was seized and burnt. The pre-
judice against it as yielding a fugitive colour, arose
from the unskilfuhless of our dyers, and their igno-
rance of the proper mordants. When this ignorance
.was removed, the act which prevented the use of this
‘dye was repealed: this occurred in 1661, when it
‘fiw'as stated that “the ingenious industry of these
times hath taught the dyers of England the art of
colours made of logwood, so that by experience
they are found as lasting and serviceable as the colour
with any other sort of dye-wood.”
i‘ i‘ The demand for logwood, after this period, greatly
’increased ;: but the supply was obtainable only in the
Spanish possessions in America. The English, how-
;ever, from the north ‘Continent of America, tempted
"bythe hopes of establishing a profitable trade, ven-
tured to cut down logwood-trees in the unfrequented
:portion of ' the province of i Yucatan, and finding that
the Spaniards‘ took no notice of their proceedings,

they soon formed a small settlement at 4 Laguna d'e‘
Terminos, within the colony, with the full knowledge
that they were intruders on the soil of other colonists.
The English settlement flourished greatly, and large
quantities of wood were shipped for New England
and Jamaica. This went on for several years, and
still without exciting the jealousy of the Spaniards,
until the supply of logwood failing at the original
spot, the settlers proceeded further into the country,
and commenced building houses, and establishing
themselves in a new district. The Spanish colonists
then suddenly arose, and seized on two English ships.
laden with logwood, in revenge for which, the English
took possession of a Spanish bark. A series of hos-
tilities then took place, which ended in the forcible
ejection of the English intruders from Laguna and
the neighbourhood. This act of justice was not long
maintained : the triumph of the Spaniards was trans—
itory, and in two or three months the persevering
English settlers had contrived to regain what they
had lost, and were cutting logwood more diligently
than ever in the old quarter. The wild and unre-
strained life of the log-wood cutter has charms of ‘its
own, which were sufiicient to detain the adventurous
Dampier for ten or- twelve months in Campeachy,
and to engage his pen in interesting descriptions.
“ The logwood cutters,” he says, “ inhabit the creeks
of the east and west lagunes in small companies,
building their huts by the creek’s sides, for the benefit
of the sea-breezes, as near the logwood groves as they
can. Though they build their huts but slightly,
yet they take care to thatch them very well with
palm or palmet leaves, to prevent the rains, which
are there very violent, from soaking in. For their
bedding they raise a barbecue, or wooden frame,
three feet and a half above ground, on one side of
the house, and stick up four stakes, at each corner
one, to fasten their curtains; out of which there is no
sleeping for moskitoes. Another frame they raise,
covered with earth, for a hearth to dress their victuals ;
and a third. to sit at when they eat it. During the
wet season, the land, where the logwood grows, is so
overflowed that they step from their beds into the
water, perhaps, two feet deep, and continue standing
in the wet all day, till they go to bed again: but,
nevertheless, account it the best season for doing a
good day’s labour in.
“ Some fell the trees, others saw and cut them
into convenient logs, and one chips 05 the sap, and
he is commonly the principal man; and when a tree
is so thick that after it is logged it remains still too
great a burden for one man, we blow it up with gun-
‘powder. The logwood cutters are generally strong
sturdy fellows, and will ‘carry burthens of three or
four hundredweight.”
The ‘logwood settlements continued to be regarded
with a hostile'eye by the Spaniards, and this led to
the attempt (which has proved‘ eminently successful)
to introduce the tree into our West India islands.
Subsequently, however, the ‘matter formed the subject
of a'treaty between the governments of England and
Spain; and the subjects of Great Britain became pos—
LOGWOOD-l-LUTES.
"20.5
.feet long.
is imparted by steam power.
sessed of a legal title to cut and ship lo'gwood in the
bay of .Campeachy. '
The logwood-tree was introduced into Jamaica in
i 1715. Seeds were procured from Campeachy, and
produced plants which in three years were ten feet
high. Plantations were then formed, and in a com-
paratively. short time the tree was to be found all
over the island, flourishing luxuriantly, either in
plantations or as single trees, or in dense hedges,
resembling our hawthorn. The full height of the
tree is from 16 to 24: feet, and the trunk is some-
times 5 or 6 feet in circumference. The stems are
crooked, the branches‘ irregular and armed with
thorns, the leaves bright and winged, the flowers in
clusters, of a pale yellow colour, with a mixture of
purple. The wood is very hard and heavy, of a deep
orange-red colour, the decoction deep violet or purple,
changing to yellow, and then black. It is made
yellow by acids, and deepened by alkalies. It can be
made very durable by the judicious use of mordants.
For a violet dye, alum and tartar are used ; for blue,
acetate of copper; for black, acetate of iron.
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Fig. 1374. LOGWOOD cn'r'rme MACHINE.
The wood is imported in large blocks about three
These are cut up into chips by means
of the machine shown in Fig. 13%, which consists of
a series of steel cutters, arranged on a drum, moving
on a horizontal axis, and to which a rapid motion
The logs are placed in
a bed-frame, and their ends are constantly urged up
against the revolving drum by a powerful lever, which
the man holds in his hand. The chips fall into a pit
xbelow the drum, and a cylindrical cover prevents
them from being scattered, and also prevents accidents
from the steel cutters.
Logwood is preferred when old, containing black
wood and very little of the white alburnum. It is
denser than water, compact, and almost indestructible.
It is excellent for fuel, and according to Dampier, is
advantageously used in the hardening and tempering
of steel. When chipped and exposed to the air, it
loses much of its dyeing power. In the dyehouse
lo‘gwood is used for the production of certain reds
and blues, but its chief consumption is for blacks,

which are obtained of various intensities by means of
iron and alum bases.
The characteristic principle of log-wood is called
fiematz'ne or kwmaz‘owyliize, and is best obtained by
pulverising the watery extract of the wood as pre-
pared for pharmaceutical use, mixing it with a portion
of sand to prevent agglutination, and digesting the
mixture with six or eight times its volume of ether;
it should be frequently shaken, and after a few days
the clear brown tincture poured off, and the greater
part of the ether distilled from it; the residue is then
mixed with water and left to spontaneous evaporation
in a lightly covered basin. After some days, the
haematoxyline crystallizes, and may be washed with
cold water, and pressed between the folds of bibulous
paper to free it from the mother liquor. The crystals
are transparent, prismatic, of a brownish-yellow, and
yield a pale yellow powder. As analysed by Erdmann,
hmmatoxyline in its anhydrous state contains (140 H17
015. Its solution is rendered colourless by sulphuric
acid. Potash and ammonia render it dark purple~red,
or if added in large quantity, they change it from
violet to reddish brown or yellow. Baryta water if
added to a solution of heematoxyline in water deprived
of air first produces a white or pale blue precipitate,
but this presently becomes blue, then red and brown.
Chloride of tin gives a rose-coloured precipitate;
alum a red colour without precipitation. The most
sensible test of haematoxyline is pure or carbonated
ammonia, which, under the influence of the air, reddens
the smallest trace of it. ‘
LOOM. See Wnavnve.
LU OIFERS. See MATCHES. ‘
LUPULIN E, the bitter aromatic principle of the
hop. See BEER, vol. i. page 113.
LUTES, (from Zutum, clay,) are soft adhesive mix-
tures, principally earthy, used either for closing
apertures at the junction of different pieces of ap-
paratus, or for coating the exterior of vessels which
are to be subjected to a high temperature, in order to
strengthen them and prevent their fracture, or for
the purpose of repairing a fracture, or for preventing
the contact of the air. .
Lutes used for the purpose of making junctions
in apparatus tight, are numerous in consequence of
the variety of vapours which require to be confined,
and the difference of temperature to which they are
subjected. The principal lutes are :—1. IS'zfourtvrz'dge
clay in fine powder :‘it should be made into a paste
with water, the consistency being regulated according
to the purposes required. It sustains a higher heat
than any other English lute. 2. Windsor loam, ob-
tained at Hampstead, &c., is a natural mixture of clay
and sand in such proportions as to make an excellent
lute. These two lutes‘ may be used for coating
vessels, or for making tight the hot joints 'of metallic
vessels. 3. Willis’s late, for making earthenware
retorts impervious to air or vapours. 1 ounce of borax
is dissolved in half a pint of boiling water, and as
much slaked lime added as will make it into a thin
paste. This is to be spread over the retort with a
brush, and when dry, a coating is to be applied of
206
. LUTES...
will be‘sufiiciently dry for use. d. Mixtures of pul-
verized borax with the-clay lutes 1, 2, or with common
clay, form fusible fluxes, useful for glazing over the
surfaces of vessels so as to close their pores. The
clay with about 115th by weight of borax may be made
‘into alpaste with water, and laid on with a brush.
5. Fat late is prepared by beating dried and finely
‘ pulverized clay, (pipe-clay or Cornish clay,) with dry-
.ing linseed oil until a soft and ductile mixture is
produced. It is used for the junctions of apparatus
which are liable to considerable elevation of tempera-
.ture,_or to prevent the escape of corrosive vapours.
The'lute. may’ be kept on by tying strips of bladder
round it, 6:‘ Par/cer’s cement mixed with water
gradually sets' and- becomes quite solid and hard. It
maybe rendered 'quite tight. by being brushed over
with a melted mixture of equal parts wax and oil. 7.
Plaster of Paris mixed with water or a thin solution
.of glue, makes a hard strong lute, but it will not sup-
port alvery high temperature. 8. Caastz'c lime mixed
‘with certain mineral and vegetable substances in
solution, affords numerous cements and lutes, which,
when dry, are hard and impervious to vapours. A
.powerful cement may be formed with lime and white of
egg diluted with its bulk of. water.
When the white
of egg is thoroughly mixed with the water, the dry
-slaked lime in powder is, to be added by sprinkling in
.enough to ‘make a. thin paste, which must be well and
quickly mixed. The mixture is then put upon slips
of cloth, and applied round the junction to be luted,
and a little dry lime sprinkled over the exterior.
'iThel substance‘ soon hardens and adheres strongly.
Instead of white of. egg a moderately strong solution
‘of glue maybe used; or the serum of blood; or a
mixture made by rubbing down very poor cheese
with water in a mortanuntil of the consistency of
‘cream. 9. Iron cement, for making permanent joints
generally between surfaces of iron. Clean iron
borings or turnings are to be slightly pounded, so as
' to be broken but not pulverized : then sifted coarsely,
mixed up with powdered sal ammoniac and sulphur,
and enough water to moisten the whole slightly. It
is then to be rammed or caulked into the joints, and
the latter drawn together as tightly as possible. The
proportions are 1 sulphur, 2 sal ammoniac, 80 iron;
no more should be mixed than can be used at once.
'10. W/n'te lead ground up with oil and spread on slips
"of cloth, is useful for making joints tight.
_ should be drawn tightly round the joint and then
bound with twine. .Tow may be used instead of cloth.
' 1'1; Moistened bladder is often useful for closing a
The slips
If .used with white of egg its adhesion is
The paste should
joint.
increased. 112. Paste and paper.
‘be well- boiled and. thick, and the paper bibulous.
Paper that‘ has...be'en pasted and allowed to dry, if
moistened on the pasted side is ready for use in a few
moments. 13., Paper prepared with a mixture of
wax and turpentine.‘l is also useful for making joints

(1) Paper with a coat of gum or paste on one side is very useful
for supplying ready labels. With a mixture of 1 part wax and it

slaked lime and linseed oil, beaten together until it‘
_ tight. Glue ‘with paper or cloth is also' useful. let.
becomes plastic. In the courseof a day or two thisi
Linseed-meal or almond-paste well beaten up with
water is a good lute for cold joints. It will not bear
a temperature above 600°. It is firmer if made up
with milk, lime-water, or weak glue. 15. Caoutekonc.
The method of forming a joint with this substance
is described under GAOUTCHOUC, Fig. 4.38 : its intro-
duction, coupled with the improved and simplified
methods of conducting chemical inquiries, may be
said to have introduced a new era into the art of
luting. “ In the time of Lavoisier, accurate joints
' were more essentially necessary than at present. The
general directions then given were to fix the apparatus
firmly, and to cement it tightly and stiffly by strong
luting. In this way many complicated instruments
were combined into one‘ great apparatus, so rigid
in all its parts as to render it almost impossible
to retain every junction perfectly close. ‘The number
of these junctions has in later times. been very
much diminished, and the introduction of elastic
caoutchouc connectors has almost entirely removed
that rigidity which was so dangerous to the appa-
ratus, and fatal to its soundness.”2 16. Yellow ware
may be used as a lute; if melted with one-eighth its
weight of common turpentine it becomes less brittle
though more fusible. It should be moulded into
cylinders or sticks, and thus preserved for use.
17. Soft eernent consists of yellow wax melted with its
Weight of turpentine, and a littleVenetian red to give
it colour. When cold, it has the hardness of soap,
but by the warmth of the fingers, and a little pressure,
it becomes pliant, and may be moulded into any form
required, It must be used at common temperatures,
and will bear a considerable amount of shaking with-
out being disturbed, which the hard lutes will not do.
By melting soft cement, and dipping a ‘cork into it, it
will secure the contents of a bottle remarkably well.
By moulding soft cement between the fingers into an
acute cone, the point will be found useful for taking
up small particles, such as crystals or fragments of
bodies, for ocular examination. It is also convenient
for effecting the adjustment of any crystal or reflect-
ing body placed upon it in the required position.
18. Cap-cement is used for making close joints at
common temperatures. It is used for attaching caps
to pneumatic apparatus, gas jars, &c. It is formed of
5 parts by weight of resin, 1' part of yellow bees’-
wax, and 1 part of red ochre, or Venetian red, in fine
powder. The earthy substances must be well dried
at a temperature above 212°. The wax and resin are
to be melted together, the powder stirred in by de-
grees, and the heat continued a little above 212°,
until all frothing ceases, and the mixture becomes
tranquil.’ Itis' then to be *allowed' to ‘cool, the stirring
being cont'mued uutili it. has become so thick that the
earthy matters will not subside by standing. Rolled
into sticks, it may be used when required by fusing
one end of a stick in the flame of a spirit lamp.

parts Venice turpentine, a coating is formed which adheres by the
warmth of the hand: labels thus prepared maybe immediately
written on, and .do not peel off. _
-. (2) Faraday, Chemical Manipulation.
LYOOPERDON—éMAGARONI—MAGHINE.
207
: In the great'chemical manufactories lutes are‘ used
much more roughly than in the laboratory. Common
mortar is used for luting gas retorts [see Gas]: and
in recently walking through the chemical works at
St. Rollox, near Glasgow, the Editor was painfully
reminded of the imperfection of the lutes. The doors
of the chambers used for the manufacture of bleaching
powder were luted with mortar, but there was a con-
siderable escape of chlorine. The workmen, however,
regarded it with indifference, and they even entered
the chambers when full of chlorine for the purpose
of raking up the layer of lime deposited on the floor
of the chamber, and they had no other protection than
a wet handkerchief tied over the mouth. In other
parts of these vast works the atmosphere was charged
with sulphurous-acid and muriatic acid gases, which
were very painful to the lungs of one not accustomed
by daily exposure to these irrespirable gases.
_ LYCOPERDON, a genus of fungi, which emit,
when burst, a quantity of dust like seeds or spores,
whence the species are commonly called jozfiealls.
The L. gigmzz‘eum is used for tinder. The powder of
1}. elavaz‘zmz is highly inflammable; it is known on the
continent under the name of vegetable Mimsz‘orze, and
is used in the manufacture of fire-works, and also in
pharmacy to roll up pills, which, when coated with it,
may be put into water without being moistened. A
quantity of this powder projected from a powder-
pufl' or bellows across a flame forms the lightning of
the theatres. This powder is also called Zj/eopodz'um.
MAGARONI, a preparation of fine wheat-flour,-
made into a peculiar paste or dough, and then manu-
factured into pipes or tubes. Macaroni is of Italian
invention, and was long known in commerce as Italian
or Genoese paste. The great seats of the manufacture
are Naples and Genoa, but the process is so simple
that there seems no good reason why it should not
be carried on in this country; indeed, it is stated that
a manufactory of this article, and of vermicelli like-
wise, has existed in Spitalfields since 1730. There
were samples of inferior macaronis of English ma-
nufacture in the Great Exhibition: those from France
were almost equal to the best Italian. Samples from
Tuscany excelled in flavour, texture, and manufac-
ture. There was also a fine series from Prussia.
The wheat used in the preparation of these luxuries
is ground into a coarse flour, called gram or semoule
by the French; and for this purpose a pair of light
mill~stones are employed, placed at a greater distance
than usual from each other. This frees the wheat
from the husk, and partially grinds it into small white
grains, which form the basis of the finest pastes, the
flour-dust being first separated by the boulting-
machine. The best and most plastic dough is made
with soft pure ‘water, in the proportion of 12 lbs.
water to'50 lbs. semoule. The water should be hot,
and the dough well worked, but as it is too stiff to be
kneaded by hand, other means are resorted to. Ac-
cording to one method, a wooden pole, about 14 feet
long, is fastened at one end by a chain to a strong
post fixed in’ the ground, so as to be moveable up and
down like a lever, the paste being placed under one

end. Two men take hold of the other end 'of this
pole, and by elevating and depressing it alternately,
and moving a little from side to side, they work the
paste very thoroughly, the power of the lever being.
very great when acting in this manner. By another,
and less agreeable method, the rough dough is piled
one piece upon another, and trodden by the feet of the
Italians for two or three minutes, after which it is
worked for two hours with a powerful rolling-pin, or
bar of wood from 10 to 12 feet long, larger at one
end than at ‘the other, and having a sharp cutting
edge at the extremity attached to the kneading-
trough. ‘
When by one or other of these processes the dough.-
has‘ been rendered perfectly smooth, it is next to be
reduced to thin ribands, cylinders, or tubes, accord:
ing as it is to be converted into vermicelli or maca—
roni. For the latter, however, a somewhat less:
compact dough is required than for the former. In
either case a hollow cylindrical vessel of cast-iron is
required, having its bottom perforated with large or
small holes, or slits, as may be needed. When the
cylinder is ~filled with paste, a piece of wood or a
plate of iron that exactly fits it is forced in by means
of a powerful press, and the paste is thus driven
through the perforated bottom of the cylinder, taking.‘
of course the shape of the perforations. Macaroni is
sometimes forced through the holes" in the form of.
pipes, but it is oftener in fillets which are formed
into tubes by joining their‘ edges together before they‘
have time to become dry. The macaroni is partially
baked during the manufacture by a fire placed beneath
the cylinder, whence it is’ drawn away and hung on‘
rods placed across a room. In a few days it is dry-
enough for use. Macaroni left in the fillet or riband
shape is called Zaeagezes. For vermicelli the holes in
the cylinder are smaller, and the dough is more tena-z
cious. The paste is forced slowly throughthe holes,;
and when the threads have reached the length of'
a .foot they are broken off and twisted into any-
desired shape on a piece of paper. Macaroni is gene-
rally brought to table dressed with Parmesan cheese ;'
it is also used in common with vermicelli for thicken-
ing soups, for puddings, &c.
MACE. See NUTMEG.
MAGERATION. See DEcocrIoN.
MA CHINE, a term applied to a variety of contri-
vances which bear but little relation to ‘each other.
Thus we speak of a bathing-machine, a coming-machine,
a threshing-machine, an electrical-machine, 850. They
agree in being more complex and artificial than the
utensils, tools, and instruments used in a primitive
state of society. Thus a bathing-machine is more
complicated than a tub, and a threshing-machine than
a flail. The ancient Greeks and Romans‘ applied the
term machine (payxazn‘y, flldOiLifld) to every tool by
which hand labour of any kind was performed; and
we still limit the word tool to an implement which
when in use is held in the hand of the operator. In
modern language, the word mac/zine is applied to such
tools or instruments as are used for some philoso-
phical purpose (as an electrical-machine, a ceezt'rzfuyal-
2.083
MACHINE.
machine, la maelzz'ae paeaa'zatz'qae, z‘. e. the air-pump,
&c'.), or of which the construction employs the simple
mechanical powers in a conspicuous manner (as in the
threshing-machine). A machine is nearly synonymous
with engine [see ENGINE], which is quite a modern
term, and appears to be limited to machines of .con-"
siderable magnitude, involving much art and‘ contri-
vanee, such as a‘ steam-engine, a: fire-engine, a boring;
eazyiaz'e, a dividing-engine, &c.
mac/zine nor engine .is‘ properly applicable to any con-~
trivance by means of which some ' piece of work is
not executed, or. materials mamg‘aczfareed: as it is
termed. Adaflzz‘ag-mae/tz'ae is certainly an inaccurate
expression. ' - ' ' '
' A machine derives its advantage in overcoming
resistance from the reaction bywhich it supports a
certain portion of the weight which produces that:
resistance, and the motive power has only to counter-.
act the remainder.
the mechanical powers [see STAtrIos], such as the
lever, the wheel and axle and the pulley, there’ is the.
resisz-‘aaeathe moving-power, and the aeaez‘z'oa of the
machine, and one of these is always found to be equal
to the sum of the two others. In any one of these
machines any portion of the resistance may be made-
to rest on the point of support, or the point of sus-'
pension. In the inclined plane, the wedge and the-
screw, the‘ motive power, the resistance, and the re-
action .of the support are represented by the three
sides‘. of a triangle, and the ratio‘ of the :first to either
of. the others (may bevaried at pleasure. -
.-* The motive powers which are-applied to any objec 3
through the intervention of machinery may consist;
of the muscular strength of men or animals; or the
actions of- weights, springs, wind, water, steam, gun--
powder; &c.‘; and. thesepowers are usually regarded-
as pressares iexerted during ' an indefinitely short
period of time. ‘The point in any machine to which the
moving powcr'is applied is called the impelled, and that.
against which the resistance acts, theworlez'ay point. -
In the use of a machine a :portion of the power,
and often very much the larger portion, is expended.
in. overcoming the inertia and friction of the materials.
of which it is composed, and that which remains is all.
that-produces any useful effect or war/c. 1 The loss .of
power from inertia is doubled when a reciprocating
motion exists in the same machine; because‘a mo'm en-
tary state of rest ensues between every two contrary:
directions of the movement, [and immediately .-af~ter-.
wards anew inertia is to be overcome.
quantity‘ of machinery is increased in" an engine, the
retarding forces are evidently augmented; so that it.
is important‘that every machine should be assimple
as the'relation‘ between the power and the resistance:
will permit; .So. also in the construction of machinery
all‘ abruptzvariati'ons of velocity should be prevented:
on. accbunt of- the irregularity. which they induce ‘in
the : action; of ,_the machine- -“ It is also a maxim-
among' engineers, that the impelled point of a machine.
should net be allowed to. move with, a- greater velocity
than that with which the motive power can act-upon '
it; sincein ‘case. the excessofvelocity the.
Neither ‘the terms
In those simple'machines, called-
'As the.

machine will be employed in accelerating the motion
of the power, and thus the general acceleration of the‘
machine will suffer a corresponding diminution. The
' velocities of the impelled and working points should,
therefore, be properly adjusted to the pressures, the
inertia and the friction, in order that all possible ad-
vantage may be derived from the machine.”
- In estimating the power of a machine, it is impos-
sible to take into account the effects of momentary
accelerations or retarclations of motion, and the loss
from inertia and friction; hence the measure of the
:‘power is" made to depend on the condition that the
impelled and working points are in a state of uniform-
‘motion. . In'such a case, as in the property of the‘
simple lever, the velocities of‘ those extreme points‘
are inversely proportional to the forces which would
be in equilibrio at the same points ; the rule is, “that
in every machine, simple or complex,-the pressure at
the impelled point, multiplied by the velocity of that
point, is ‘equal to the product of the resistance at
the working point by the velocity of the same point ;
or the momentum of resistance-(called the perform-
aaceof the machine) is equal to the momentum of
' impulse.” .
Professor Robisonll has ofiered some well-considered
objections to this rule, as it respects the measure of
the power in action. A writer in the Penny Cyclo-
paedia (article Machine) contends ‘that it affords a
correct value of the useful effect ; and that this may
be measured by the weight which might be raised by-
the machine to a given height vertically, in a given
“_ The’ fact is sufiiciently evident, when a mass-
time.
of any material is to be conveyed from one place to
another, or when a body is let fall on any object from‘
a given height. - It follows that if an algebraical/
expression be obtained for the momentum of the re--
sistance in terms involving that resistance, the motive»
power and the distances of their points ‘of application
from the axis of “,motion; on making the differential
of that expression equal ‘to zero, the ratio of the re-
sistance to the .moving power, when the useful effect
‘of the machine is a maximum, may be found from the
resulting equation. If M represent the mass of a‘
body moved, w its weight, which is equal to in 9,
=9 (2.32%- feet). expressing the force of gravity; also,-
if a be the height to which the body may be raised in
‘one second of time, and v the velocity which a body
would acquire by falling vertically through a height
equal to 11,. wenshall have by the theory of motions,
v2 z: 2 g n; whence w H (the momentum of resistance,
or the useful effect of a machine) : 5 M v2.

‘ (1)-See arr—‘admirable article "entitled Machinery in the second
'volume of the:f-‘_Sy§,tgm_ of. Mechanical Philosophy. ”. .
This‘
jlast expression-is designated-the living, or aezfz'ceforee'
;of the :body. moved; and ‘it expresses the force of a
,§.body in? motion, in contradistinction to the simplei
.ipressui'e'exercised by a body 'at rest.”
,tIt’ is'bft’en stated that, in employing machinery, as
-_.much is'Ilost in timeas is‘ gained in power, or that the
jmomentum of resistance is proportional to the’ power
employed. This’ rule is applicable when the object
MACLE—MADDER.
909
moved resists by its inertia only‘; “ but if the in-
ertia is but a small part of the resistance, the mo-
mentum of the latter, or the work done, is found
to increase nearly as the square of the power em-
ployed.”
MACLE, a term applied to crystals of andalusite,
which show a tesselated or cruciform structure when
broken across and polished. This structure appears
to be due to impurities from the gangue disseminated
during crystallization in a regular manner along the
sides, edges, and diagonals of the crystal.
_ MADDER, a well-known red dye, exceedingly
valuable on account of the various shades of colour
which can be obtained from it by means of the several
mordants employed by the dyer, and also for the per-
manency of the colours thus produced. The madder
plant, Radio tz'zwz‘orz'a, is a native of the Levant, and
of Italy, the south of France, and Switzerland. It
is cultivated successfully Holland, Russia, and
other countries, but does not succeed in England. It
is a luxuriant trailing plant, sending forth numerous
large square jointed stems, armed with prickles, and
bearing six or eight spear-shapedjleaves in a whorl at
each joint, the whole terminating in a loose spike of
yellow flowers. The stalks are annual, but the root,
which is the valuable part of the plant, is perennial.
It is composed of many long thick, succulent fibres,
covered with a black bark or rind; ‘when this is
removed they appear of a reddish colour and semi-
transparent, with a yellowish pith in the centre. The
taste is bitter, and the smell strong and peculiar.
The plant is propagated by shoots, which are planted
in August, a foot apart, and allowed to remain two
seasons, with attention to weeding. In the second
year the plants blossom, and come to perfection:
after their leaves‘ have fallen off the roots are taken
up, and carefully dried and cleaned for the market.
When the roots are suficiently dried outwardly by
the action of the air and of kilns, they are then
thrashed like corn for the purpose of removing the
outer skin. This gives an inferior madder, called mall,
which is packed away separately, and sold at an infe-
rior price. The naked roots are now carried back to
the kiln and subjected to a higher degree of heat than
before, a current of air being introduced into the
kiln, to carry off the exhalations from the plant, which
would injure its colour. In very warm climates the
roots are dried without artificial heat. After this
they are ground into a coarse powder, which is of a
dingy red or orange colour, and very apt to be dete-
riorated by moisture. The grinding is performed
between mill~stones or under knives similar to those
of a tan-bark mill. The powder is milled and bolted
to different degrees of purity. In some cases the
fresh root is more valued as a dye than the prepared
madder; but its bulk becomes troublesome, and it
cannot be preserved for any considerable period with-
out deterioration. Nevertheless, madder, in the root,
is largely exported flom the seats of this trade. It is
a singular circumstance respecting madder, that the
bones of animals become tinged with the colour, when
the roots are given them as food. In a growing
VOL. II.

animal, alternate layers of white and red bone may be
obtained by the alternate use and disuse of this food. 1:
Madder affords an adjective dye, but this becomes
permanent when the cloth to be dyed is previously
prepared by boiling in a solution of alum and tartar.
The colour is less brilliant than that from cochineal,
but it is much less expensive, and is therefore the
ordinary red'dye for stuffs and cottons, but not for
silks. It is peculiarly convenient in calico-printing,
for by the use, of different mordants every variety of
tint may be obtained from pink to deep red, and from
lilac to black. With a portion of weld or quercitron
added to it, all the shades of brown and orange may
be also produced. Tin, iron, and aluminous bases, as
well as other mordants, are used for this purlpose.
Madder has been carefully examined by eminent
chemists, but the nature of its colouring principle is as
yet but- little understood. It has been doubted by
some inquirers whether the variety of shades produced
are due to the combination of madder with the differ-
ent mordants, or whether several colouring matters
are not contained in the substance itself, and seve-
rally precipitated or retained by the varying action
of different agents. Two distinct colouring matters
at least are clearly perceptible in madder, a fawn and
a red, and the admixture of the former tends to dimi-
nish the brilliancy of the latter. In the far-famed
Turkey-red, the red colouring matter alone is preserved;
therefore, this colour is not only more brilliant, but
more durable than the other reds obtained from
madder. _
Bladder-purple is obtained by washing the roots,
and then repeatedly boiling them in a strong solution
of alum, and filtering while hot. A brownish red
substance falls, which is chiefly madder red: this is

(1) In a paper contributed by the Editor to the Penny Maga-
zine, No. 856, this curious subject is treated at some length. The
following are the chief points in the investigation :—About the
year 1736, Mr. Belchier, surgeon, of London, dining at the house
of a calico-printer, noticed that the bones of a joint of pork were
of a_red colour, when he was informed that the hogs kept at the
establishment had usually mixed with their food the bran which
had been boiled with printed calicos in order to brighten the
madder dye. Belchier tried a few experiments on this subject,
and recorded ‘the result in the Philosophical Transactions for
1736. In 1739 Duhamel repeated the experiments on chickens,
pigeons, and sucking-pigs. The bones were coloured red, and on
withholding the madder they appeared to regain their usual
colour; but, it was found that the red was merely concealed by a
deposit of white bone. Haller, Hunter, and others were interested
in the subject, and they found that no point of ossification, how-
ever delicate or isolated from the rest of the osseous system,
escaped the colouring action of the madder. In 1839 Flourens
took up the subject: he found the action often to take effect in
a few hours. It was noticed that in the eyes of pigeons fed on
madder, a. red circle was seen round the iris, the only portion of
the eye that was so coloured. It was found that in'birds there
exists between the two plates of that portion of the eye anterior
to the cornea, a circle of minute osseous pieces, which is absent
in mammalia. By feeding a number of young pigs of the same
age alternately upon food mixed with madder, and free from
madder, he arrived at the conclusion that, in the growth of the
bones, while fresh deposits are being made upon the exterior sur-
face of the bone, absorption goes on within ; so that as the whole
diameter of the bone becomes increased, the internal canal is err-
larged. The growth of the teeth is even more remarkable, for it
is stated, that while the addition of fresh dental matter (deniine)
is made on the interior, there is absorption on the external face.
The enamel of teeth, cartilage, feathers, nails, claws, &c., are not
coloured by madder, .
P
210
MADDER.
separated, and sulphuric acid added to the clear liquor,‘
which then throws down, by degrees, madder-purple:
this is collected, boiled with hydrochloric acid, to
separate alumina, and lastly digested in alcohol:
from this tincture the greater part of the alcohol‘is
distilled, and the residue, on spontaneous evaporation,
deposits the so-called purple as a crystalline powder.
This furnishes a rose-coloured solution in water,
a deep red or purple solution in alcohol or ether.
Acids render it yellow, alkali-s deep red; chalk,
boiled with the solutions, removes the whole of the
colouring matter. Mulder-red, which forms the prin-
cipal part of the precipitate just alluded to, is sepa-
rated byboiling in dilute hydrochloric acid, and then
dissolving in alcohol. This solution, with alum, is
heated to boiling, when the madder-red is thrown
down in a purer form. It is further purified by dis-
solving in ether, when, on evaporation, it remains
a yellow-brown crystalline powder. This gives to
boiling water a dark~yellow colour, to alcohol and
ether a reddish-yellow. With acids it is yellow, with
ammonia purple, with caustic potassa violet. Madden
omvzge is obtained by digesting the washed roots for
16 hours in 8 parts water at 60°, and straining the
infusion, which then deposits small crystals. These
are dried and dissolved in boiling alcohol : the deposit
which forms on cooling is madder-orange, which is to
be washed with cold alcohol till the washings are no
longer reddened by sulphuric acid. It then forms an
orange-yellow powder, which when dissolved in boil-
ing water forms on cooling yellow flocks. With
caustic potassa its solution becomes rose-red, with
ammonia reddish brown. The colouring matter is
removed by chalk. There are also madder-yellow
(Zara/zine), and madder-brown ,- but the above, either
singly or combined, give the various tints employed
bycalico'printers.
The terms alz'zar'z'izc, gaurparz'rze, and gammz'ize, have
been applied to maddenred and madder-purple, or to
their sublimed products. Alizarine has been repre-
sented by the formula Cs? H12 010.
An important branch of industry has of late years
sprung up in the south of France in the preparation
of garancine for exportation instead of the root. For
this purpose the roots are first moistened with dilute
sulphuric acid, and then exposed in considerable
masses to a boiling heat by means of steam, by which
the colouring matter is altered and improved for cer-
tain dyeing processes, and the quantity of soluble
matter considerably increased. Spent madder, in-
stead -of being thrown away, is now also used as a
source of garancine. It is treated in the same man-
ner as the fresh roots, and thus a considerable quan-
tity of colouring matter is recovered. The garancine
in either case produces a more scarletty red than the
ground root : ' it also affords good chocolate and black
without soiling the white ground; but it is not so
well adapted for purples, lilacs, and pinks.
‘Many very beautiful and dm'able dyes of red and
purple are obtained under the name of Achz'mzojalé or
Turkey-reds. . The‘ processes for these are very tedious
and complicated, and the reasons for their adoption

not well understood. Oil, sheep’s dung, calf ’s blood,
gall-nuts, soda, alum, and afterwards a solution of
tin, have all been considered necessary to produce the
rich tints in question; but some of these are dis-
pensed with by our most eminent calico-dyers. A
description of the German method, as practised at -
Elberfeld, will give an idea of the nature of the ope-
rations. One hundred pounds’ weight of cotton is
first cleansed by boiling 4! hours in a weak alkaline
bath“ It- is then cooled and rinsed preparatory to
immersion in a steep made of 300 lbs. of water, 15lbs.
potash, 1 pailful ‘of sheep’s dung, 12%lbs. olive oil.
In this it is worked about, and then left for a night,
after which it is drained, wrung out, and dried. The
steeping and drying are repeated 3 times. It is
next placed in a bath containing 120 quarts of water,
18 lbs. potash, and 6 qrts. olive oil, then wrung out
and dried. This treatment is repeated 4 times. After
this the cotton is steeped in the river for a night,
slightly rinsed, and hung up without wringing to dry
in the air. A warm bath of sumach and nut-galls is
then prepared, and in this the cotton remains during
a night, being strongly wrung afterwards and dried
in the air. Alum, potash, and chalk are next em—
ployed, the cotton wrung, and worked well through
the bath, in which it is left for the night. Draining
and strong rinsings follow, which are repeated, with
steeping in water to remove any excess of alum from
the fibres.
After all these preparatory processes the cotton is
ready for maddering. Blood, sumach, and nut-galls
are added to the madder : the bath is brought to the
boil in an hour and tln‘eaquarters, and is kept boiling
half an hour. The cotton is then rinsed, dried, and
boiled from 241 to 36 hours in a covered copper, with
an oily alkaline liquid: then rinsed twice, laid for two
days in clear water and dried. The last process, and
that which gives the greatest brightness, is the boil-
ing the cotton for three or four hours in a soap bath
containing muriate of tin. Further steeping in water,
rinsing, and drying, close this long series of opera-
tions.
The Glasgow methods diifer in some respects from
the above, but are productive of a beautiful and well-
known Turkey-red. Unbleached calico is subjected
to a fermentative steep for 24! hours, and washed at
the dash~wheel. It is then boiled in a lye of 11b.
soda crystals to 12 lbs. cloth. After this comes oiling:
a bath is prepared consisting of Gallipoli oil, sheep’s
dung, solution of soda crystals, and of pearl-ash, with
water making a milk-white soapy solution. This is
put into a cylindrical vat, and agitated with wooden
vanes; after which, it is let off, as it is wanted, into
the trough of a padding machine, in order to imbue
every fibre of the cloth in its passage. The padded
cloth is often laid aside in wooden troughs for more
than a fortnight, when it is again padded with the
soapy liquor and spread out to dry. This is some-
times repeated a third and a fourth time, until the
cloth is quite varnished with oil. It is then cleansed
to a certain degree by being passed through a weak
solution of pearl-ash, at the temperature of about
MADDER—MAGAZINE—MAGMA—MAGNE SIUM.
211
122° Fah., after which it is squeezed between rollers
and dried. But this does not complete the oiling
process. A second system now commences, the liquor
being similar to the first, but without any admixture
of sheep’s dung. In this the cloth is padded as
before, and passed through the squeezing rollers,
which return the superfluous liquor to the padding-
trough. The cloth is then laid on the grass, and
finally hard dried in a stove. These processes are
often repeated three times, and the cloth becomes so
oleaginous as to require cleansing again in lye of soda
crystals and pearl-ash. In recapitulating these ope-
rations, it appears very much as if the whole were
a system of doing and undoing, and it cannot but
occur to the scientific chemist, that a large field of
inquiry is opened as to the nature and treatment of
this valuable dye. It is aflirmed that in the cleansing
which follows upon the oiling of the cloth, a consi-
derable portion of the alkalies enters into combination
with the oil in the interior of the cotton filament.
The gelling of the cloth is a very important step in
the preparation of Turkey-red. About 20 lbs. of
Aleppo galls, bruised and boiled for 8 or d hours in
25 gals. of water, is the proportion for 100 lbs. of
cloth, but to make it successful all the oil must have
been thoroughly saponified by the previous processes.
The cloth is well padded in the decoction of galls,
(sumach is sometimes substituted in the proportion
of 2 lbs. for every 1 lb. of galls,) the temperature of the
mixture being kept at 90°. Fah., then passed between
‘squeezing-rollers, and dried. It is next transferred
to a solution of alum, to which a certain portion of
chalk is added, and in this mixture it is winced and
steeped 12 hours.
Madderz'rzg is the next process, and for this 2 or
3 lbs. of m-adder, ground to powder, are taken to every
pound of cloth. The cloth is put into the bath while
cold, and winced by the automatic reel, until the
liquor boils, and during two hours afterwards, in
which the boiling continues. Bullocks’ blood, in the
proportion of 1 gallon for every 25 lbs. of cloth, is
put into the bath while cold.
After the maddering comes a clearing process, to
remove a dingy brown colouring matter which is asso-
ciated with the fine red, and which is more fugitive.
Every 100 lbs. of cloth are therefore boiled for 12
hours in water containing soap and soda, together
with some of the residual matter from the last
cleansing. This nearly removes the dun colour in
question, but it is finally got rid of by a second boil
at a heat of 250°, in a globular copper, with 5 lbs. of
soap and llb. muriate of tin crystals, dissolved in
a sufficient body of water for 100 lbs. of cloth. This
muriate of tin raises the cloth to a scarlet hue. When
weather permits, the goods are laid out on the grass
for a few days.
Many variations are introduced by different dyers,
and so great is the importance attached to the process
in France, that its particulars have been enumerated
by government officers, and directions and recom-
mendations given oflicially on the subject.
MAGAZINE, a strong building of brick or stone

for containing. gunpowder and other warlike stores.
As gunpowder is liable to injury from damp, the
situation must be selected so as to ensure dryness,
and as uniform a temperature as possible. The
magazine should be remote from other buildings, and
furnished with metallic lightning conductors, and
surrounded by a wall and ditch. In some cases, it
may require to be made shell-proof. The dimensions
vary with the quantity of powder to be stored. Ac-
cording to Vauban, magazines made in the ramparts
of fortresses, should be from 8 to 12 feet wide, with
semicircular headed vaults; the barrels of powder to
be arranged in them in two rows, with a passage from
3 to 41 feet wide along the middle. The magazines
constructed in this country on a large scale, consist
of several parallel vaults, each about 90 feet long,
and 19 feet wide, separated from each other by brick
partition walls, communicating by doorways, and
there is a doorway at the extremity of each vault.
The side walls are from 8 to 10 feet thick, and are
strengthened by buttresses. “ The concave or interior
surface of each vault in a vertical and transverse
section, is nearly of a parabolical figure above the
springing courses, and the exterior surface has the
form of two inclined planes meeting in a longitudinal
ridge line above the middle of the vault. The thick-
ness of the brick-work forming the vaulted roof, is
therefore various. At the crown it is 7 or 8 feet,
and on the hances about 3 feet, this being considered
suflicient to resist the shock of falling shells. The
vault on the exterior of the inclined planes, is covered
with flat tiles, and the gutter between every two
roofs with sheet lead or copper. The height inte-
riorly, from the level of the floor to the crown of the
arch, is 19 feet; and the lines at which the vaulting
springs from the side walls, are at half that distance
above the floor. The narrow vertical perforations
which are made through the side and end walls, for
the purpose of giving air to the interior, are cut so
as to leave a solid block or traverse of the brickwork
in the middle of the thickness of the wall; the line
of the perforation branching laterally from its general
direction, and passing along the two sides of the tra-
verse. By this construction, while air is admitted,
no object capable of doing mischief can be thrown in
from the exterior of the building. The flooring»
planks are of course laid on joists raised considerably
above the ground. One vault of the dimensions
above given, would contain 2, 500 barrels, or 225,0001bs.
of powder.’2
MAGMA, a crude mixture of mineral or organic
matters in a thin pasty state.
MAGNESIUM (Mg. 12), the metallic base of
magnesia, was discovered by Davy in 1808, and its
properties first made known by Bussy in 1830. It
has the colour and lustre of silver, and is to a certain
extent ductile. It changes much less slowly in the
air than potassium and sodium, and does not decom-
pose water at low temperatures. At 86°, water
begins to be decomposed, and at 212° rapidly.
Heated in the flame of a spiritslamp, it burns with
intense light into magnesia.
r2
212
-. MAGNESIUM.
The only compound of magnesium and oxygen, is
magnesia MgO. It is usually procured by exposing
the carbonate to a red heat. Magnesia is a bulky
white insipid powder, of sp. gr. of about 3. It has
a slight alkaline reaction upon sensitive vegetable
colours ; but water which has been agitated with it,
and then filtered, does not produce that ‘effect. It is
nearly insoluble in water. Cold water dissolves
between 6010 0th and filfith part; at 212° water dis-
solves-fi—gfith part. " When exposed to air, it absorbs
moisture and carbonic acid much less rapidly than
the other alkaline earths ; - but bypouring water upon
it, it is slowly converted into a lzyclrale, MgO,H().
The hydrate has. been found native in Serpentine.
Magnesia is almost .infusible: a mixture of lime and
magnesia is scarcely more fusible than the earths

separately. Caustic magnesia is useful in cases of‘
poisoning with arsenious acid, or common arsenic. It
combines with this acid, and forms an insoluble com-
pound. The hydrate, but_not the carbonate, can be
used for this purpose. "
Magnesia forms saline compounds with the acids:
they have a bitter taste. The sulphate is‘ also distin-
guished from the sulphates of the other alkaline earths
by its solubility. A few of the more remarkable salts
of magnesia need only be distinguished here.
Sulphate of magnesia Is’lgQSOs, is found in
certain mineral springs, as those of Seidlitz, Leyd-
schutz, Egra, and formerly Epsom, in Surrey, whence
the name of Epsom calls. It appears in these cases to
proceed from the reaction of the sulphate of lime
held in solution in the water upon .the 1magnesian
limestone of the soil. Water charged with sulphate
of lime,‘ remaining for a considerable time in contact
with the magnesian rock, reacts upon the carbonate
of magnesia, and carbonate'of lime is deposited,'_while
sulphate of magnesia is dissolved. The latter salt
may be obtained in a crystalline form by evaporation.
This method of forming sulphate of magnesia may
be illustrated by filtering slowly, and many times in
succession, water saturated with sulphate of lime
through a thick layer of magnesian limestone: the
water will soon be found to contain sulphate of mag-
nesia only. The reverse of this experiment is instruc-
tive. If carbonate of lime and a solution of sulphate
of magnesia be heated to about 400° or 41300 in a
thick glass tube sealed at both ends, the result will
be the formation of sulphate of lime and carbonate
of magnesia. , In this way, the natural magnesian
limestones are formed by the reaction of carbonate
of lime upon‘ sulphate of magnesia dissolved in the
thermal waters of the earth.
Sulphate of magnesia is also obtained by the action
of sulphuric acid upon calcareous rocks rich in car-
bonate of magnesia, such as rlolonzile. The rock is
calcined, and reduced to powder by being sprinkled
with ‘water 5 it is ‘then diffused through water, and
sulphuric acid is added: sulphate of lime and sul—
‘phate of- magnesia are formed, the one scarcely soluble
in‘ water, and‘ the other very much 0; hence they
are easily separated. ' i ’ ' -
Epsom salts are also manufactured largely from

the billern, or mother liquor left after the evaporation
of sea-water, and the separation of common salt
therefrom. [See SAUL] This bittern consists chiefly
of a solution of chloride of magnesium, and sulphate
of magnesia. The process formerly adopted at
Lymington, in Hampshire, was as follows :-—During
the summer, when the manufacture of salt was
carried on, the bittern was collected in underground
pits until the winter season, which afforded leisure
for the conversion of this waste product. The
bitter liquor from the pits was boiled for some hours
in the pans which were used insummer in the prepa-
ration of common salt, and the impurities which rose
to the surface removed by skimming. During the
evaporation, a portion of common salt separated, and
this, being too impure for use, was reserved for the
purpose of concentrating the brine in summer. The
evaporated bitter liquor was then removed into
wooden coolers 1 foot deep, where it remained 2d
hours, during which time, in clear and cold weather,
the sulphate of magnesia crystallized at the bottom,
in quantity equal to about %th of the boiled liquor.
The uncrystallizable fluid was then let off through
plug-holes at the bottom of the coolers, and the
Epsom salt, after being drained into baskets, was
deposited in the storehouse. This formed single
Epsom salts, and after having been dissolved and
crystallized a second time, it was termed doable
Epsom salts. Four or five tons of sulphate of mag-
nesia were produced from a quantity of brine that
had yielded 100 tons of common salt, and 1 ton of
what is called cal-call.‘ In some places, the bittern
is decomposed by hydrate of- lime, which is mixed
with it in tanks, and the resulting precipitate after‘
wards treatedlwith sulphuric acid, by which sulphate
of magnesia and sulphate of lime are formed.
Hydrated sulphate of magnesia, MgO,SOg,7HO,
crystallizes at the ordinary temperature, in four-sided
prisms, with reversed dihedral‘summits, or four-sided
pyramids. They are doubly refracting, and their
density 1'7. If the crystallization takes place at a
high temperature, the salt contains only 6 equivalents
of water, and if crystallized at a low temperature,
(below 32°, for example,) large crystals are obtained,
containing 12 equivalents of water. Heated to about
460° sulphate of magnesia still retains 1 equivalent
of water, but loses it at a higher temperature. The
anhydrous salt fuses at a red heat into a white
enamel. The crystals are soluble in about their own
weight of ;_water at 60°, and in three-fourths their
weight of boiling water, 100 parts of water at 32°
dissolve 2576 parts of the anhydrous salt, and for
every degree above that temperature, they take up
026564: parts additional. Sulphate of magnesia is
much more soluble in hydrochloric acid than in water'.
Exposed to air, the crystals when pure have alslight
tendency to efiiorescc ; and the salt of commerce will
even deliquesce in consequence of the presence of a
little chloride‘ of magnesium. The salt of commerce
is sometimes adulterated with small crystals ‘of sul-
phate of soda, a fraud which may .be deteeted'by the
' -‘ XI) 'Dr. Henry; Philosophical’Transactions; 1810. _4 ‘

MAGNESIUM.
.213
inferior weight of the precipitate of hydrated carbo-
nate of magnesia occasioned by adding carbonate of
potash.
Sulphate of magnesia combines with the alkaline
sulphates, and with sulphate of ammonia, forming
double salts, which crystallize easily.
Nitrate of magnesia is formed by dissolving white
or calcined magnesia in dilute nitric acid: it is deli-
quescent and very soluble in water: it is entirely de-
composed at a red heat, and leaves a residue of pure
magnesia.
Carbonate of magnesia in its native form is known
as magnesite: it is found in Piedmont and Moravia,
and also in North America, in veins of serpentine
accompanying the native hydrate. It also occurs in
combination with carbonate of lime, with which it is
isomorphous. Most of the calcareous rocks contain a
small quantity of magnesia. The species of marble
called Dolomite, which occurs abundantly in the Alps,
contains about 40 per cent. ot carbonate of magnesia ;
it is a double carbonate of lime and magnesia,
CaO,CC)2+MgO,GC)2. The magnesian limestone of
Derby and Nottingham is generally of a yellowish
colour: it dissolves less rapidly in dilute hydrochloric
acid than the purer limestone, whence the French
term it eliaaa' earbonate’e lente. It affords excellent
lime for cements, but is not adapted to agricultural
purposes, probably in consequence of the lime re-
maining caustic so long.
When an alkaline carbonate is poured into a
solution of a salt of magnesia, a white gelatinous
precipitate is formed, which is a hydrocarbonate of
magnesia, or a combination of the hydrate and of the
carbonate of magnesia. The proportions of these two
compounds vary according to the quantity of alkaline
carbonate employed, the strength of the solutions, and
the temperature. This product is prepared in large
quantities in pharmaceutical chemistry, and is the
magnesia alba of the pharmacopoeia. Two kinds
identical in composition are prepared, viz. the light and
the lzeavg. “ For lzeaog magnesia, add 1 volume of
a cold saturated solution of carbonate of soda to a
boiling mixture of 1 volume of a saturated solution
of sulphate of magnesia, and 3 volumes of water:
boil until efiervescence has ceased, constantly stirring
with a spatula. Then dilute with boiling water, set
aside, pour off the supernatant liquor, and wash the
precipitate with hot water on a linen cloth: after-
wards dry it by heat in an iron pot. Ligfit magnesia
is prepared by employing dilute solutions of the sul~
phate of magnesia and carbonate of soda. If no heat
be used, it is apt to be gritty. A heavy and gritty mag-
nesia is prepared by separately dissolving 12 parts of
sulphate of magnesia, and 13 parts of crystallized car-
bonate of soda, in as small a quantity of water as
possible, mixing the hot solutions, and washing the
precipitate?" The light cubes of magnesia are pre-
pared as follows :—-A solution of 100 parts sulphate
of magnesia in 100 of water is put into a vat heated
by steam ; a solution of 125 parts of crystallized car-
bonate of soda is quickly stirred into it, and the
(1) Pereira: Elements of Materia Medica.


temperature raised to 17 6°, to expel carbonic acid,
which holds some of the magnesia in solution: the
liquor is then decanted off the precipitate, and this is
washed three times by subsidence and decantation
with luke-warm water, free from salts of lime: it is
then transferred to linen strainers, and allowed to
drip from 24: to 4:8 hours, and is transferred in a wet
state to cubical boxes without bottoms, placed upon
a table of plaster or porous stone, which quickly
absorbs the water: after some time, the boxes are
turned upside down, so as to present the upper side
of the magnesia to the absorptive surface: the drying
is completed in warm rooms.
The carbonate of magnesia of commerce is also
prepared in various ways from bittern. It is also
separated from magnesian limestone by a process
adopted by Mr. Pattinson, which consists in calcining
it at a dull red heat, by which the magnesian carbo-
nate only is decomposed: the calcined stone is then
diffused through water and subjected to the action of
carbonic acid, under pressure, by which the magnesia
only is dissolved and is afterwards obtained by rapidly
boiling down the solution.
By passing a current of carbonic acid through a
mixture of water and carbonate of magnesia, a clear
solution is obtained, which, surcharged with carbonic
acid, is a useful preparation, which has been exten—
sively advertisedunder the name of salable magnesia,
or 6i-earlzonate of magnesia. This compound ‘cannot
be obtained in the solid or crystalline form, for the
solution gives by evaporation oblique rhombic prisms
of hydrated carbonate of magnesia, which, on being
put into cold water are decomposed, carbonate of
magnesia being dissolved, and a sub-carbonate de-
posited.
There are several phosphates of magnesia. The
ammonio-magnesian phosphate is deposited from
human urine, often in the form of white sand, or as a
crystalline film: it also forms calculi. Phosphate of
magnesia is present in the husk of grain, in the
potato, and other plants; and the supply in the soil
of phosphoric acid and magnesia is kept up by animal
manures: phosphate of magnesia is also found in
turf, ashes, and in good malt liquor.
Several silicates of magnesia occur in nature.
Meersc/zaam, or Eeame ale Mei‘, so much esteemed by
the tobacco smoker, is a hydrated silicate of magnesia,
MgO,SiO3,HO; but as the compound is not crystal-
line, its constituents are variable, and silicates of iron
and of alumina occur with it: these affect the
colour of the meerschaum, which, when pure, is quite
white. The presence of silicate of iron imparts a
tint varying from pale yellow to deep brown. Good
meerschaum is soft enough to be indented by the
thumb nail: it yields readily to the knife, especially
after having been wetted. The fracture is usually
earthy, seldom conchoidal. The state of aggregation
is so variable as to give rise to various densities:
some kinds sink in water, others float on its surface:
those of medium density are preferred by the pipe-
maker, for the light varieties are porous, and even
cavernous, and the heavier kinds are often made up
2141
MAGNESIUM—MAGNETISM.
artificially. Most of the meerschaum is from Asia
Minor: it is dug chiefly in the peninsula of Natolia,
near the town of Coniah; but it is also found in
Spain, Greece, and Moravia. It is exported in the
shape of irregular blocks, with obtuse angles and
edges. Much care is required in removing the irre-
gularities and faulty portions, and even then it may
contain various defects, such as difi'erent minerals dif.
fused through it, and also a hard variety of meer-
schaum, called by the'manufacturer e/zal/rs (Krez'cle-
masserz), which occasions much dificulty in the carving;
In some cases the meerschaum is roughly fashioned
into bowls on the spot where the material is dug, and
they are more elegantly carved in Europe. Pesth
and Vienna were formerly celebrated for this manu-
facture. In forming a bowl, the meerschaum is pre-
pared for the operation by soaking in a composition
of wax, oil, and fats. The wax and oil absorbed by
the meerschaum are the cause of the colour produced
by smoking: the heat of the burning tobacco causes
the wax and fatty substances to pass through the
stages of a dry distillation, and becoming associated
with the products of the distillation of the tobacco,
are‘ diffused through the substance of the bowl,
and produce those gradations of tint which are so
much prized. In some cases the bowls are artificially
stained by dipping them, before being soaked in wax,
in a solution of sulphate of iron, either alone or mixed
with dragon’s blood. The parings which are produced
in roughing out the bowls are formed into what are
called mam-awe, or massa-bowls: the parings are
triturated to ‘a fine powder, boiled in water, and
moulded into blocks,‘with or without the addition of
clay: each block is then cut into a bowl, but as it
contracts considerably, it must be left some time to
dry. There was a fine'display of mecrschaums in the
Austrian department of the Great‘ Exhibition. Com-
position pipe bowls and cigar tubes'were also exhi-
bited. Referring to these, the Jury Report states
that “these bowls are distinguished from real meer-
schaums by their greater specific gravity, but there is
no very certain test by which the real. meerschaum
can be distinguished from the composition, and many
suppose that all the heavier descriptions are spurious,
though there is no absolute proof of this being the
case. A negative test may, however, be mentioned :
the composition bowls never exhibit those little ble-
mishes which result from the presence of foreign
bodies in the natural meerschaum; therefore, if a
blemish occur in a meerschaum bowl, which is very
frequently the case, the genuincness of the bowl is
rendered most probable; but as blemishes do not
show until after the bowl has been used for some time,
the test is'not of much value.”
Magnesian minerals are often soft and apparently
greasy‘ to the touch : ' they have seldom any lustre or
transparency, and are ‘generally more or less of a
green colour.- Slealz'le or soap-stone, tale. and arteries,
are examples. Olzrysollle contains more than half its
weight of magnesia. Biller-spar contains 4.5 per cent.
carbonate of- magnesia, 52 carbonate -of lime, and a
little iron‘ and manganese: it is generally of a yellow—

ish colour and a pearly lustre, semitransparent' and
brittle. The finest specimens are from the Tyrol,
but a variety found at Miemo in Tuscany is called
Miemz'le. Boracz'le is a native borate of magnesia.
MAGNETISM is the science which treats of the
phenomena exhibited by magnets, (such as the load-
stone, or' bars of steel, to which similar properties
have been communicated ;) of the reciprocal action of
magnets upon each other; of the laws of the forces
which they develop‘; of the methods of making
artificial magnets; and of the magnetic phenomena
exhibited by the globe which we inhabit. The term
is derived from the Greek word, ‘adj/11179, the load-
stone, or native magnet, from Magnesia, a country in
Lydia, where it was first discovered. Our limited
space will not allow us to do more than just indicate
a few of the leading points in this beautiful science.
The peculiar properties possessed by the natural
loadstone, or magnetic iron ore, can be imparted to
iron and steel without altering their other qualities,
such as weight, hardness, &c. The most obvious of
these properties is that of azfz‘raelz'rzg, and in some
cases repelling certain other bodies; but the most
useful property of the magnet is its directive power,
or that of pointing in a certain direction, when
allowed to move freely. The attractive power of the
magnet was known in Europe many centuries before
its directive power, and it was not until the latter
was understood that the compass conferred upon the
art of navigation extended powers, by means of which
the New World was discovered, the most distant parts
of the earth were visited, explored, and peopled, and
commerce became the true civilizer. This directive
power of magnets depends greatly on their attractive
power, respecting which it is necessary to make a few
remarks. The power of attracting iron or steel does
not belong equally to all parts of a magnet. If a
loadstone be dipped into iron filings, they will not
adhere to its whole surface, but chiefly to certain
spots, of which there are never less than two; so
also an artificial magnet (which is in the form of a
long bar, either straight, or bent like a horse-shoe),
displays no attractive power at its middle, but at its
two ends that power is most strongly developed.
Now, although the two ends of a magnet attract
equally, they possess a certain opposition of pro-
perties, which is called polarity, and on this account
the two ends are termed the poles. This opposition
may be observed by means of two artificial magnets,
in each of which one end is distinguished from the
other end by a notch. If the marked end of one
magnet be presented to the unmarked end of the
other, they will attract each other twice as strongly
as either of them would attract common iron; but
between two similar poles, whether both marked or
both unmarked, there is no attraction, but on the
contrary a repulsion, which, however, being weaker
than the attraction, is not generally perceived unless
one of the magnets be either floating or suspended
by a fine‘ thread attached to its centre, or poised upon
a fine point by means of a small cup inserted into its
centre. [See GoMPAss] When a straight and slender
_ MAGNETISM.
215
‘steel magnet, called a needle, is so poised, as shown
in Fig. 137 5, and is not within the
influence of any other magnet, or
piece of iron, it always assumes a
certain position in preference to any
other, and this position is the same
Thus, all the


Fig.1375.
for all needles at the same place.
magnetic needles in London that are not disturbed
by wind or other forces, are now pointing with the
marked end 23° west of north, and consequently the
unmarked end 23° east of south, or nearly so. Their
position varies by small fractions of a degree at dif-
ferent hours of the day, and different seasons of the
year, and also undergoes a very slow but continual
change from year to year. All these changes are
subject to laws of great complexity, which cannot be
.said to be well understood.
Now, although the needle of a compass is com-
monly said to point north and south, such is not now
the case in London, nor has been since the year
1658. Before that year the marked end of the needle
pointed eastward of north, and ever since it has
pointed westward; but this westerly variation, as it
is called, reached its maximum, which was about
at 712°, in 1815, and is now diminishing; that is, the
needle is slowly reapproaching the lane meridian, or
north and south line. But the amount of this
magnetic variation is very different at difl'erent places,
and over one half of the world it is easterly instead
of westerly. Hence, it is of great importance to
navigation that its exact amount, and the laws by
which it may be calculated at different spots, should
be known. Fig. 1376 will convey a rough idea of
the various directions which the needle assumes in
different parts of the world. It will be seen that
there are very few
places where it lies
on the meridian, or
north and south, as
. at A and B; for
’ while the meridians
_ all tend to two
‘ . points, or poles, viz.
the ends of the
earth’s axis, the
direction of the


needle, or magnetic
_ meridians, tends to
two other points, only one of which is seen in the
figure, marked by a black spot. This point is
about 19° from the north pole, in the direction of
Hudson’s Bay; the other, or coat/i magnetic pole,
is in the continent of Victoria Land, and has
been approached within 160 miles. ' On approaching
either of these points, the needle must obviously
vary greatly from the meridian, and change its direc-
tion rapidly. .At the magnetic pole itself the
needle shows no tendency to point in any direction,
and between this and the true pole, the variation
becomes more than 90°, so that the marked end of
this needle, commonly called its north pole, becomes
the southernmost. Thus the earth influences all the
Fig. 1376.

magnets on its surface, just as if it were itself a
great magnet, having its unmarked pole- north of
Hudson’s Bay, and its marked pole in Victoria Land;
and this huge magnet, like all natural loadstones,
has its power very irregularly distributed, so that
the direction of the needle at any spot can only be
exactly found by experiment; and lines passing
through all the spots where it has the same direc-
tion, or lines qf egaal variation, are. not regular, but
very complex and irregular, curves. Nor is the line
of no variation a regular meridian, but a waving circle,
passing through both the true poles, and both the
magnetic poles. In 1658 this line must have passed
through England, but since that time it has shifted
westward about a quarter of the earth’s circum-
ference, so that it now passes through the two
American continents, and England is left nearly as
far from it as possible. The other half of this line
passes through Australia and China, and is gradually
approaching us as the American line recedes from us;
so that the magnetic poles seem to have a very slow
westward revolution round the true poles of the
earth.
As the directive tendency of the needle arises from
its poles being attracted by those of the earth, it is
evident, from the rotundity of the earth, that its poles
will not pull those of the earth horizontally, but
downwards, so that the needle cannot tend to be
horizontal, except when acted on by both the earth’s
poles equally, that is, when it is midway between
them. When nearer the north magnetic pole than
the south, its north or marked end must be attracted
downwards, and the contrary when it is nearest the
south pole. Accordingly, a needle which was accu-
rately balanced on its support before being mag-
netised, will no longer balance itself when magnetised,
but, in this country, its north pole will dip, or appear
to be the heavier end; and this has to be corrected
in ships’ compasses by a small sliding weight attached
to the southern half, which weight has to be removed
on approaching the equator, and shifted to the other
side of the needle when in the southern hemisphere.
The dip of the needle may be illustrated by the
following experiment :--Let N s, Fig. 1377, be a
magnetic bar, 30 inches long, about a inch thick,

\ 92
I '5 a’ 0 a 5
HF ' ' 0 o . J '1}
Fly. 1377.
and 1 inch wide, and let as be a small magnetic
needle, about 2 inches in length, suspended by a
filament of untwisted silk, immediately over the
magnetic centre 0, so as to be a full length distant
from it. At this point the needle will retain its
horizontal position, its axis being parallel to the axis
of the magnet beneath, and its poles ns in a reverse
1216"
- MAGNETISM.
position to the poles N s of the bar. Let this small
needle be gradually moved along over the magnetic
surface Ns, and it will be found to take different
degrees of inclination, the inclination being greater
as we approach either pole N s, at which points it
will be 90°. It will also be seen in the course of
this experiment, that the‘ south pole s dips on the
north polar side of the centre a, and the north pole n
on the south side‘.-
In order to measure the dip with accuracy at any
place, the needle is mounted so as to move freely in
a vertical plane, instead of a horizontal one, as in the
compass, or in Fig. 1375. An approved form of dip-
ping needle, as constructed by M.‘ Gambey, of Paris,
is shown in Fig. 1378, iu'which N s represents a light
magnetic bar, or needle, ‘of a long lozenge form,
about 10 inches long, which, before being magnetised,
is set on a short axis am, and is very accurately
poised about its centre of gravity, through which
the axis is passed, so as to remain indifi’erently in any
position. The axis a a is turned down at its extre-
mities to very fine cylindrical pivots: these rest on
two finely polished agate planes aa, supported on
two cross bars of a light rectangular frame F F’.
The platform supporting
this frame is solid, and
fixed to a circular plate
beneath, which is accu-
rately ground to a similar
plate fixed on a vertical
pillar r, so that by means
, of a vertical axis, which
‘plays in a socket in P,
the whole may be turned
. evenly and centrally
, round into any azimuth.
There is a spirit-level
8! on the solid platform,
which also supports a
' finely divided circle 8 e Z,
in the plane of which
the bar N 5 moves.' The axis war is so placed as to
pass accurately through the centre of this ‘circle.
The whole is mounted on the central pillar 1?, and can
be turned into any required azimuth about a supposed
vertical axis cc’, passing through the centre of the
needle. The precise angular quantity through which
the needle is turned, is measured by a vernier 22,
attached to the under part of the platform, and a
graduated azimuth circle 2 fixed to the pillar P. The
whole is placed on a light but firm base, furnished
with three levelling screws 8’, for levelling the instru-
ment. The vertical circle 8 Z c is divided upon silver to
l0’- of a degree. The agate pieces a a are adjustable
to the same horizontal ‘plane by screws bearing upon




their lower edges, and there is a light interior frame
.acted on by a lever above 1?’, furnished with Y-pieces
at am, and moveable 'on an axis at one extremity F,
.by which the axis of the needle N s may be lifted off '
the agate. planes a a, and‘be again let down on them
:without disturbing its final position. The whole is
covered by ‘a light case of wood and glass, resting on

the platform (but not shown in the figure), in order
to shield the needle from dust and air; and there are
also two moveable arms attached to a horizontal bar,
connected with the case, which carry lenses for read-
ing off the degrees of the divided circle 8 a Z.
In taking an observation with this instrument it
must first be‘ accurately levelled, and the graduated
circle 80 Z then adjusted in the magnetic meridian.
“This is effected either by removing the needle of
inclination, s N, and placing a balanced horizontal
needle, made expressly for the purpose within the
frame F a a F’, or in any other situation adapted to
it, or by turning the instrument so as to bring the
needle into a vertical position. It'will then be at
right angles to the magnetic meridian; and we have
then only to turn it 90° from this point, as shown on
the azimuth circle Z. Having determined the direc-
tion of ‘the magnetic meridian, the plane of the circle
sol is finally secured in that direction bya small
clamp screw at r. We now remove the horizontal
needle, if that be employed, and replace the needle of
inclination s N, allowing it to vibrate freely. When
it is at rest we turn the milled head lever above 12',
and lift the axis aa gently off the agate planes by
means of the Y-pieces: when again let down it will
be accurately in the centre and in the plane of the
divided circle. Supposing we'had an absolutely per-
fect instrument, the needle would now mark the
precise angle of inclination at the place of observa-
tion ; but there are mechanical errors quite insepa-
rable from the construction of the instrument, which
we can only hope to compensate by a mean of experi-
ments. We therefore, first, take a few successive
observations, and note thevangle at which the needle
rests after putting it into vibration. This should be
repeated with the axis a a reversed in position on
the agates. We then turn the face of the instrument
1809, as shown by the circle 2, and make a similar
number of observations. We now remove the needle
N s, reverse its poles, and take a similar series of ob-
servations; so that we have then to take the mean
of a given number of observations, say 10 :—
First, with the face of the instrument, suppose
- to the East.
Second . . . . . . . . . to the West.
Thirdly, with inverted poles . face to the East.
Fourthly . . . . . to the West.
The nearer these observations accord the more per-
fect is the instrument 3 but they will certainly differ
by some small quantity. If we add the whole toge-
ther, however, ‘and divide by the number of observa—
tions, 'the resulting quotient will be very near the
true inclination of the‘ needle. Thus the inclination
of the magnetic needle in the gardens of the Athe-
naeum at Plymouth was found to be in November
1831, by Gambey’s instrument, 69° 27' 6”.” l
' In' London, in 1830, the dip was 69° 38'. The
various positions of the ' dipping needle at different
parts of the earth’s surface are represented in Fig.

(1) Sir W. 'Snow Harris, Rudimentary Magnetism,- published in
Weale’s Series. This cheap work contains an admirable exposi—
tion of ‘the science of magnetism. '
' MAGNETISM.
217
137 9. The linesof eqaal (lip are much simpler than
those of equal variation, and resemble parallels of
latitude, only irregularly waving as here shown. The
line of no clip, or the magnetic egaator, deviates in
g some places 12°
‘ ‘ from the true
equator; but it is
not quite settled
whether it crosses
that line four times
or only twice. But
as it is dependent
on the magnetic
poles, it must, like
all the magnetic
lines, be gradually
shifting westward,
and thus the dip, as well as the variation, at every
place is constantly changing; that in England, for
example, is very slowly diminishing. This angle, too,
suffers very small changes, dependent on the hours
and the seasons.
There is also a third magnetic element, as it is
called, which is subject to variation both from time
and place; viz. the intensitg of the force by which
the needle is pulled into its peculiar position. This
is found to be generally greatest near the earth’s
poles, and least at the line of no dip; but it varies
irregularly over the surface. The importance of in-
vestigating its laws will be obvious when we consider
that the great and increasing use of iron in the con-
struction of ships, must draw their compass-needles
out of the true position; and this would lead to error
unless accurately calculated and allowed for. Now
the less the effect of the earth’s magnetism, the more
will the needle be disturbed by the iron on board, so
that to make the proper allowance, the variations of
the magnetic intensity at different spots must be
known. In order to determine the exact amounts
and changes of these three magnetic elements, the
direction, the intensity, and the dip, magnetic obser-
vatories have been erected, temporarily or perma-
nently, in different distant spots on the earth’s surface,
in which long series of careful observations have been
and are being made. In order to carry on similar
observations near the magnetic poles, arctic and
antarctic expeditions have been fitted out.1
The first great application of magnetism to the
useful arts, is undoubtedly the Manrnnn’s COMPASS,
and second only in importance to it is the application
of the magnetic needle to the ELECTRIC TELEGRAPH.
There are also a few minor applications which require
a brief notice.
Dr. Scoresby has applied magnetism for the pur-
pose of determining distance through matter which
| . I . -
a I I
' ' r a ' '


Fig. 1379.

(1) Sir James Clark Ross had the honour of discovering the
north magnetic pole, and also of approaching within 160 miles of
the south magnetic pole. An analysis of his southern expeditions
is given in a small work compiled by the Editor, and entitled,
“ Summer in the Antarctic Regions; a Narrative of Voyages of
{Discovery towards the South Pole."I Published under the direc-
tion of the Committee of General Literature and Education,
appointed by the Society for Promoting Christian Knowledge.
'1848.

would be otherwise impermeable, such as a solid
rock, or other substance, and this method has been
found useful in driving tunnels and in other mining
operations. The principle of the application will be
understood if we consider that, as the force of a mag-
net is measured by the deviations of a delicate needle
under the influence of such magnet placed in the
line of its centre at right angles to the meridian; so,
conversely, the same deviations under similar condi-
tions of direction, must correspond with equality of
distance, supposing the intervening matter to be per-
meable or transparent to magnetism. 1f, therefore,
we determine for a given magnet and needle, a table
of deviations corresponding with certain distances
between the centre of the needle and magnetic pole
when placed in a given position, we may thereby
determine the distance at which the magnet is ope-
rating through solid matter, by observing the deviation
produced. For example: let ONM s, Fig. 1380, be
a mass of solid rock, s N the direction of the magnetic
meridian, and that the walls of the mass lie in that
direction: let G be W/\\/“
a delicate compass,
finely divided and N
placed on one side 6'

of the rock, and M, % El
a magnet placed
perpendicular to its S
centre on the other1
the compass-needle Fig-138%
will then be deflected a certain number of degrees;
from which the distance may be found either by
the table, or by bringing the magnet round to one
side of the compass, and finding experimentally the
distance at which the same amount of deviation
will be produced. If the intervening rock should lie
oblique to the meridian in direction s N, and the
compass-needle become oblique to the walls, we must
then deflect it by the influence of an auxiliary magnet,
so that it may stand parallel to the walls of the rock,
and then proceed as before. By a careful prepara—
tion of the apparatus Dr. Scoresby has succeeded in
measuring distances of 126 feet to within a very small
fractional amount?
Magnets are also employed for separating and col-
lecting particles and fragments of iron mixed with
other finely divided matter. It was also proposed
many years ago to protect the dry grinders of cutlery
from the noxious effects of the metallic dust which
pervaded the air of the grinderies, by furnishing them
with masks of magnetic steel wire, which it was
thought would so filter the air as to deprive it of its
noxious character. It is true that the magnetised
wire would retain the ferruginous particles, and thus
be of some service; but it would have no influence
on the stone-dust from the grind-stones; this dust
would enter the lungs of the men, and in the course
of a very years produce organic disease. There may
‘also be some truth in the statement, that the men
refused to wear the masks, lest by removing the un-

(2) Edinburgh New Philosophical Journal, 1832. Harris’s Rudi-
mentary Magnetism.
‘ 218
MAGNITUDE—MAHO GANY.
healthiness of the ‘occupation numbers should be
attracted ‘into it, and thus wages be diminished.
At any rate, the only effectual remedy for the terrible
' evils of dry-‘grinding, is in efiicient ventilation, as‘ stated
in our article Curnnur. _
In our Inrnonnoronr ESSAY, page ciii, reference
is made to a‘ method adopted in Canada, of separating
the ‘iron of certain -rich ores from its gangue by
means of magnets.
MAGNIFYING POWER. See LIGHT.
MAGNITUDE is that of which greater or less can
be predicated when two of the same kind are com-
pared together. The term is generally taken as syno-
nymous with quantity, and is even applied to aamter.
The answer to the question“How much?” describes the
quantity, and the answer to “ How great ‘9” describes
the magnitude. Magnitude in our language is usually
applied to amount of space, hence quantity is the
general term, and magnitude the quantity of space.
- MAHOGANY (Szez'eleaz'a Ma/wgaaz'), the most
important species of a small genus of plants named
in honour of Gerard van Swieten, a physician of Ley-
den. It is a native of Campeachy and of the West
Indies, where it is a lofty tree with a large spreading
head ‘and glossy pinnate leaves. The trunk frequently
exceeds ac feet in length, with a diameter of 6 feet. The
timber, well known for its general use in furniture
and cabinet making, is of a rich red-brown, of different
shades and markings, capable of a brilliant polish,
close-grained, very little liable to warp or shrink, and
having a semi-resinous juice which preserves the
wood from the attacks of insects. Mahogany is im-
ported from several of the West India islands, and
from the Spanish main. It arrives in logs about 10
feet long and 2 feet square. Honduras mahogany
is imported in logs from 2 to 4.‘, or even 6 feet
square, and from 12 to 1.8 feet long. This variety is
lighter in colour, and more open and irregular in grain
than the Spanish. By some botanists the Honduras
mahogany has been described as a different species;
but it appears probable that differences of soil and
situation have produced the variations in quality.
There are woods called mahogany, brought from
Africa and the East, but they belong to other genera,
and are decidedly inferior ' to the true mahogany.
A specimen of the latter, however, was sent from the
Botanic Garden, Calcutta, to the Great ‘Exhibition,
and its fine quality proved that the true variety
may be raised in the East Indies. The value of
the best Spanish mahogany may be judged of by
the fact, that the Messrs. Broadwood gave 3,000l.
for three logs of fine mahogany, each 15 feet long
and 38 inches square. These logs were the pro-
duce of a single tree. The wood was exceedingly
beautiful, and when polished, it reflected the light in
a varied manner, offering a different figure in what-
ever direction it was viewed. These logs were brought
to this'country with a full knowledge of their value;
but, generally speaking, the purchase of this wood is‘
a sort of‘ lottery. . Dealers in mahogany often intro—
duce an anger before buying a log; but this does not
always enable them to judge with precision respecting

the quality of the timber. Honduras mahogany grows
mostly upon moist low land, and is generally soft,
coarse, and spongy. It has, however, the advantage of
holding glue admirably, and is, in consequence, much
used as a ground on which to place veneers of the
finer sorts of mahogany. The cutting of mahogany
at Hondiuas is carried on twice a-year—at Midsum-
mer and soon after Christmas. The mahogany of
Cuba and Hayti, and of the islands in general, is
close-grained, dark-coloured, and sometimes highly
figured: it is known as Spanish mahogany. The
general appearance of the tree is extremely beautiful,
and has been thus described :——“ In the rich valleys
among the mountains of Cuba, and those that open
upon the bay of Honduras, the mahogany expands to
so giant a trunk, divides into so many massy arms,
and throws the shade of its shining green leaves,
spotted with tufts of pearly flowers, over so vast an
extent of surface, that it is dificult to imagine a
vegetable production combining in such a degree the
qualities of elegance and strength, of beauty and
sublimity.”
Mahogany may be safely pronounced the most
useful of all furniture woods, for which it is par-
ticularly adapted on account of its size, abundance,
durability, and beauty, and from the fact that it holds
the glue better than any other wood. It is much
used for founders’ patterns, and other works in which
permanence of form is of great consequence. It
is also employed for a variety of turned works.
Mahogany, in common with all other large foreign
woods, requires to be carefully dried after it is cut into
planks, as, notwithstanding the long time which may
intervene between the felling and the using, it con—
tinues, so long as it is in the log, to retain much of
its moisture. Well-seasoned Spanish mahogany cuts
well, takes a brilliant polish, resists scratches, stains,
and fractures much better than inferior sorts, and is
worth the trouble and delicate workmanship which
are often expended upon it. The colours are brought
out by the application of oil or varnish, but much
washing or soaking of the wood in water will destroy
its beauty and render it of a dingy brown. The
colour of mahogany is often artificially deepened by
alkaline applications, but the best effect-is produced
by the use of a colourless varnish, which allows the
natural tints of the wood to be displayed unaltered.
From the resemblance of the seed'vessel of the
mahogany-tree to that of the Barbadoes cedar, the
name of cedar has been sometimes erroneously applied
to it. There is so far a correspondence in the nature
of these trees that the mahogany, like the pine tribe,
succeeds best upon the coldest soils and in the most
exposed situations. When it grows on moist soils
and warm lands, it becomes coarse and spongy, and
the timber is not secure from the attacks of worms.
The first mention of this beautiful timber occurs
in'1597, when it was used to repair some of Sir
Walter Iialeigh’s ships at Trinidad. Yet the timber
was not sent to this country until about the beginning
of the last century, when a few planks brought over
as ballast_ in a vessel from the West Indies, were
MALIC ACID44MANGANESE.
219
given to Dr. Gibbons, and would have been used, but
for their hardness, by his workmen in erecting a
house in Covent Garden. Having been rejected by
them, a piece was given to a cabinet maker, named
Wollaston, with the request ‘that he‘ would make a
candle-box of it. This being done, the candle-box
proved so beautiful that it became an object of
curiosity, and the despised mahogany came into great
request, and was soon ‘established as a valuable
material for household furniture.
MALACHITE. See Corrna—Inrnonucronr
EssAY, page cxix.
MALIC ACID. This acid, first obtained by
Scheele in 17 84, from the juice of apples (whence
the term from the Latin malam, an apple), is the most
widely diffused of all the vegetable acids: it occurs
partly in a free state and partly in combination with
potash, lime, magnesia, and some organic bases.
Unripe fruits owe their sour taste to the presence of
this acid. It is usually prepared from the berries of
the Sorbets aacapavia, or mountain-ash. The juice of
the berries is obtained by expression, clarified by
boiling with the addition of white of egg, and then
filtering: a solution of acetate of lead is added, and
the resulting precipitate washed with cold water:
boiling water is next poured upon the filter, and
allowed to pass through the precipitate into glass jars :
after some hours crystals of malate of lead are depo-
sited: these are boiled with 23 times their weight of
dilute sulphuric acid of sp. gr. 1090. The clear
liquor is to be poured off, and while still hot, a stream
of sulphuretted hydrogen is to be passed through it
to precipitate the remaining lead: the liquid is then
filtered, and when boiled so as to expel the excess of
sulphuretted hydrogen, is a solution of the pure
vegetable acid. The composition of malic acid is
(3811408, 2H0. By careful evaporation the liquid
concretes into mamillary masses of imperfect aricular
crystals. It is deliquescent and very soluble in alcohol
and water. Nitric acid converts it into oxalic acid.
It forms salts with bases. The malates are mostly
soluble in water, but insoluble in alcohol, with the
exception of the malate of the peroxide of iron.
Malic acid does not render lime water turbid, but on
evaporation crystalline mala'te of lime separates, which
is redissolved by boiling. This serves to distinguish
malic acid from oxalic, tartaric, racemic and citric
acids. When malic acid is heated to 300° it is trans-
formed into pgi'omalic acid, also known by the names
famam'c, lic/zenic, or paramalmic acid, 04H03,HO.
It is found in the Famaria ofifeinalis, in Iceland moss,
and other plants. Its salts are termed filmai'ates. At
a temperature a little above 390° malic acid is con-
verted into malmic or mafaric acid, CgH206, 2H0.
‘The salts of this acid are termed vzalmates.
MALLEABILITY. See METAL—ALLOY.
MALT. See'Bnnn.
MALTHA. See ASPHALTUM.
MANGANESE, (Mn 28.) This simple metallic
body bears some resemblance to the alkaline metals
potassium, sodium, calcium, 850. in having a powerful
affinity for oxygen, and attracting it from air and

water with avidity: its oxides are very difficult to
decompose, but they have none of the chemical pro-
perties of alkaline bodies; indeed, in its highest state
of oxidizement, manganese forms acids. 'As a metal,
manganese has seldom, if ever, been obtained in a state
of chemical purity: the purest specimens have been
found to contain carbon. The metal is obtained by
reducing one of its oxides by means of carbon at a
high temperature. It is described as a grey metal,
possessing a certain amount of ductility; it can be
filed, but breaks under the hammer; it resembles in
its colour and fracture certain varieties of cast or pig-
iron. Its density is about 8. It decomposes water
rapidly at 212°. To preserve it from the oxygen of
the air it is kept in naphtha, or, still better, in a glass
tube hermetically sealed.
There are five compounds of manganese and oxygen,
of which three are oxides and two acids: there are
also two intermediate oxides, the red oxide and the
mineral named Varvicite. The protonide of manga-
nesc, M110, may be obtained by passing a current of
dry hydrogen over the deutoxide or peroxide of man-
ganese, contained in a porcelain or iron tube exposed
to a heat which is to be gradually raised to bright
redness: water is formed, and a dingy green powder,
which is the protoxide. There are other methods of
procuring it, for a description of which we must refer
to chemical treatises. It is soluble in dilute acids,
and is the basis of the ordinary manganesian salts.
If caustic potash be poured into a solution of one of
its salts, a white precipitate is obtained, which is the
ligdrate rg" t/ze protoa'ide .' it absorbs oxygen rapidly
from the air, and changes into the hydrate of the
sesquioxide. The sesgaiorcide, also known as manganic
onide or deatonirle g manganese, MngOg, may be pro-
cured by exposing the protoxide or carbonate of
manganese to a red heat in an open vessel, when it
absorbs oxygen and is converted into a deep-brown
powder; or by exposing the protonitrate of manga
nese to a red heat the sesquioxide is left as a black
powder. This oxide differs in its behaviour to solvents
with its state of aggregation. It gives a violet, or in
small portions, a pink tinge to glass, and is said to be
the colouring matter of the amethyst. It also forms
the: mineral termed Zivaanite. The ligdrated sesqai-
oxide of manganese MngOe-l—HO, may be obtained by
exposing the hydrated and moist protoxide to the
action of air. It forms the manganite of mineralo-
gists. Binoaide, or peroxide of manganese, M1102, also
called the blaclc oxide, is the common ore of manganese,
and is the usual source of the other combinations of
this metal. Before its nature and composition were
known, it was called magnesia nzgra, from its resem-
blance to the loadstone; and indeed it was long in-
cluded among the ores of iron. It is found in Devon-
shire, Somersetshire, and Aberdeenshire, in various
forms, compact'and massive, pulverulent and crystal-
lized. Its sp. gr. is 418 to 49. It forms the pgrola-site 1
(1) Hfiphfire, and Mew, to set free, or loosen, from the facility with
which it evolves oxygen under the influence of heat. Graham
refers the origin of the term to the common use of manganese as
a. glass soap, from a-Up, fire, and Aofiaw, to wash, in discharging
colour-from glass. [See Grass]

220
MANGANESE.
of mineralogists. It is sometimes contaminated with
small portions of carbonate of lime, silica, oxide
of iron, baryta, and some other substances. It is
largely used in science and the arts as a source of
oxygen, and in the manufacture of bleaching powder.
It is used to give the black colour to earthenware,
— and it is said to have the. property of sweetening foul
water, or preventing it from becoming putrid. At a
red heat it loses oxygen and becomes converted into
the sesquioxide. [See OXYGEN] It is a good con-
ductor of electricity. It does not combine with the
acids; but those acids which appear to dissolve it
reduce it to the state of protoxide. Heated with
hydrochloric acid, chlorine is evolved. [See CHLO-
RINE] Ajtg/drai‘edjieroreide ofmaagarzese is formed by
precipitating protochloride of manganese by chloride
of lime. The soft black mineral, called wad by the
miners, is a hydrated peroxide. Red oxide of mam/a-
riese, M11304, occurs native, and forms the mineral
termed Haasmarzrziie. A peculiar oxide of manganese
has been found at Hartshill in Warwickshire, to
which the term Varoicile has been given from its
locality. Maagaaic or Maayariesic acid, MnOf’. “When
peroxide of manganese is heated to redness with
nitrate of potassa, a compound is obtained, which,
when put into water, furnishes a solution exhibiting
various tints of green, purple, and red, and which
was therefore called Clameleori mineral. A similar
compound is more perfectly obtained by fusing the
peroxide with caustic potassa at a red heat, which
furnishes a green substance when the alkali is in
excess. With water it afi’ords a deep green solution
of manganate of potassa, which is permanent with
excess of alkali, but otherwise becomes blue, purple,
and ultimately red on exposure to the air, in con-
sequence of the formation of permanganate of potassa
by the absorption of oxygen; at the same time it
deposits a brown powder, which is hydrated peroxide
of manganese, and free alkali is separated.”1 Man-
ganic acid has not been isolated. Permaagarzic or
liypermaagaaic acid, M112 ()7, has been isolated as
a hydrate by various processes, one of which is as
follows :——A manganate of baryta is first formed by
heating nitrate of baryta with peroxide of manganese
to redness; the green powder, thus formed, is reduced
to a fine powder, mixed with water and a little dilute
sulphuric acid added, by which a red solution of per-
manganate of baryta is obtained: this is concentrated
by evaporation and carefully decomposed by sulphuric
acid: the supernatant solution of permanganic acid
'is then decanted off. “ The aqueous solution of per-
manganic acid is of a splendid carmine colour, or by
transmitted light, dark violet: its taste is austere
and bitterish : it tinges the skin brown, and gives the
same tint to ‘ litmus and turmeric paper, depositing
:hydrated peroxide: it is soon decomposed at a boiling
heat, and by the greater number of combustible bodies
'at common temperatures. Its salts, which are of a

(1) Brande’s Manual of Chemistry. This work contains a full
‘account of the compounds of manganese and their applications;
.-but the most ample account is in the fourth volume of Mr.Watts’s
‘excellent Translation of Gmelin’s Handbook of Chemistry, pub-
lished by the Cavendish Society,_1850.

fine red or purple hue, are more permanent than the
hydrated acid: they defiagrate with combustibles ;
they are all soluble in water, and many of them deli-
quescent.”--Braade.
There are three chlorides of manganese ; an ammoaio
clzloride and a chlorate; an iodide and an iodai‘e; a
bromide and a lromaie; two fluorides; a citrate and
a salp/zaref. The salp/zazfe of manganese, MnO,SOe is
much used in dyeing and calico printing, for which
purpose it is prepared, according to Graham, by
igniting peroxide of manganese mixed with about one-
tenth its weight of pounded coal in a gas retort. The
peroxide thus formed is dissolved in dilute sulphuric
acid with the addition, at the end, of a little hydrochlo-
ric acid; the sulphate is evaporated to dryness and _
again heated to redness in the gas retort; the iron is
found after the ignition in the state of peroxide, and
insoluble, the persulphate of iron being decomposed,
while the sulphate of manganese is not injured by the
temperature of ignition, and remains soluble. The
solution is of an amethystine colour, and does not
readily crystallize. When cloth is passed through
sulphate of manganese and afterwards through a
caustic alkali, protoxide of manganese is precipitated
upon it and rapidly becomes brown in the air; or it
is at once peroxidized by passing the cloth through a
solution of chloride of lime. The colour thus pro—
duced is called maagarzese aroma.
A sesgaisalp/taie of manganese, MnzOe-l-gsOg, is
formed by dissolving the sesquioxide in sulphuric
acid: the solution is of a crimson colour: when
heated it gives off oxygen and becomes colourless.
With sulphate of potash or ammonia it forms double
salts crystallizing in octohedrons: these are manga-
aese alams : they are similar in constitution to the
ordinary alum, but with A12 03, replaced by M11203.
Manganese forms several compounds with phospho-
rus. It also combines with carbon, and it is said that
the quality of steel is improved by the presence of
carburet of manganese. A substance resembling
plumbago, occasionally produced in iron furnaces, and
called kick, is said to consist chiefly of ' carburet of
manganese. A carlorzaie of manganese is precipitated
as a hydrate, by alkaline carbonates, from the proto-
chloride or protosulphate. There is also a native
carbonate, or spat/rose maagaaese, MnO,CC)2. Man—
ganese also combines with cyanogen and boracic
acid.
Most of the salts of manganese containing the pro-
toxide are soluble in water: the solution is colourless,
or (unless quite pure) slightly pink, of a bitterish
astringent taste, and often becomes turbid and brown
by exposure to air. They are not precipitated by
sulphuretted hydrogen; they furnish White precipi-
tates with the alkalis, which become discoloured by
exposure: the alkaline carbonates throw down white
precipitates, which change to purple; they are preci-
pitated white by ferrocyanide of potassium, and flesh-
colo'ured- or reddish brown, by hydrosulphuret of
ammonia. If peroxide of lead be heated with dilute
nitric acid and a solution of manganese added, the
liquid assumes the purple tint of permanganic acid,
. MANOMETER.
22L
which becomes very evident as the peroxide subsides;
minute traces of manganese may be detected in this
way. Manganese and its compounds are also readily
detected by blow-pipe tests.
MANGEL-WURZEL. See BERT—SUGAR-
MANGLE. See GALENDERING.
_ MANHEIM GOLD. See BRASS.
MANNA. See SUGAR.
MANOMETER, from pal/59, flzz'rz or rare, and
pe'rpov, a measm'e, an instrument for measuring the
rarity of the atmosphere, or other gas. The rarity
of a gas is proportional to its elastic force, and so
long as the temperature and chemical composition of
a gas remain undisturbed, it is sufilcient to construct
the instrument so as to measure the elastic force of
the gas under examination. The simplest form of
this instrument was Boyle’s statz'ml barometer : it con-
sisted of an exhausted glass globe, suspended from
one arm of a delicate balance, and counter-poised by
a metallic weight at the other, the adjustment being
made when the mercurial column of a common baro—
meter marked 30 inches, showing the air to be in its
state of mean density. As the globe displaced its
own bulk of air of mean density when it was counter-
poised, it is evident that any variation in the density
of the air would disturb the equilibrium, an increase
of density causing the globe to ascend, and a diminu~
tion causing it to descend.
For the correction of barometric observations,
manometers, consisting of glass tubes of various
sizes, resembling thermometer tubes, have been em-
ployed. Such are the manometers of Captain Phipps
and Colonel Roy. Those of Colonel Roy were from
4 to 8 feet long, with bores from 1-1-5-th to 5% th inch in
diameter. The bulb and part of the tube being filled
with air of known tension, and the rest of the tube
with a short column of mercury, sufiicient to cut oil’
the communication between the outer air, and the air
enclosed in the tube; it is evident that any change in
the density of the outer air would be accurately
measured by the ascent or descent of the mercurial
column; for when the elastic tension of the surround—
ing atmosphere exceeded that of the air in the tube,
the column would move towards the bulb, and vice
verse’. If, however, the change in the tension of the
atmosphere were partly due to a change of tempera-
ture, the motion of the column would merely measure
the difierence of the variations in the tension of the
internal and ‘external air, since the tension of both
would be greatly affected by the change of tempera-
ture. The bulb was pear-shaped, and the point being
occasionally opened, dry or moist air could be ad-
mitted, and the bulb sealed again without any sensible
alteration in its capacity. From the adhesion of the
mercuryin the tube, it was necessary, in order for the
instrument to act truly, to keep it in a vertical
position.-
A more convenient form of instrument is the sz'pfizm-
barometer, the basin of which is enclosed, air-tight, in
a globular vessel furnished with a number of cocks,
‘by means of which and the air pump, or exhausting
andcondensing syringe, the gas contained in it may
A
be removed, and some other gas substituted. If
equal weights of different gases be introduced in
succession, they will not be affected by any change in
the surrounding atmosphere, except with respect to
temperature; and provided the temperature remain
constant, the relative tensions of these gases will be
accurately measured by the weight of the mercurial
column, suspended in the longer arm of the baro-
meter, above the level of the mercury in the basin,
the same precautions being used as in the barometer,
to allow for differences in the level of the mercury in
the basin, from variations in the height of the
column.
If the air be pumped out from the receiver sur-
rounding the bason of the barometer, and a small
quantity of any liquid be introduced, it will be con-
verted into vapour, the elastic force of which may be
measured in the same way as that of permanent
gases. The receiver may be made large enough to
contain animals, or plants, and their effect in in—
creasing or diminishing the tension of the enclosed
gas, is measured by the rise or fall of the mercury.’
The exact determination of the elastic force of steam,





gen;
11


Fig. 1381.
ARRANGEMENT OF MANOMETE R.
at high temperatures, was undertaken some years ago
by the Royal Academy of Sciences, at the request of
the French government, and the Report of the Com-
missioners, MM. de Prony, Arago, Girard, and
Dulong, is contained in the 4:35! vol. of the Annales
de Chimie. The manometer used in these experi-
222
MAP—MAPLE --MARBLE.
‘a
ments was a straight glass tube it‘, Fig. 1381, of
uniform bore, 1'7 metres (67 inches) long, and 5 milli-
metres in internal diameter and the same in thickness,
closed at the upper, and open at the lower extremity.
The capacity, having been accurately determined, it
was filled with dry air of known density, and enclosed
in a cistern of water. 0 kept at a-uniform tempera-
ture. by water constantly pouring into it, and escaping
at the lower extremity, as shown in the figure.
Another tube of equal bore and thickness, l’, 26 me-
tres (85 feet) in length, and open at both ends, was
then erected, vanchthe lower extremities of the two
tubes were made to communicate with apertures in the
opposite sides of a cylindrical reservoir It, capable of
holding about 1 cwt. of mercury. On the top of
this. reservoir was aforcing pump 22, by which the
pressure upon the surface of the reservoir could be
increased as desired; and the increased pressure being
transmitted to the. lateral apertures, caused the
mercury to rise unequally in both tubes: in the
longer tube it rose until the weight of the mercurial
column, together with that of the superincumbent
atmosphere, were equal to the pressure; but in the
shorter tube only until this pressure was counter-
balanced by the rapidly augmenting expansive force
of the confined air, added to the weight of the small
column of mercury forced into it. The expansive
force of the_compressed air was measured by the
difference between these two columns 5 and the shorter
tube was carefully graduated so as to correspond to
pressures varying from 1 to 29 atmospheres. In
this way the manometer having been formed, the
longer tube and the forcing pump were removed, and
instead of the latter, the actual pressure of steam at
successively increased temperatures was substituted,
the tension of which was indicated by the compres-
sion of the air in the manometer.
MAP, (Latin mappa, a napkin,) a representation of
the surface of a sphere, or a portion thereof on a
plane. Although the term is usually applied to repre-
sentations of the earth’s surface, ierreslrial maps, yet
we have celestial, or astronomical maps to represent
the sphere of the heavens. Terrestrial maps are of
two kinds, geographic, or lanel maps 5 and hydro-
ai'ajJ/iic, sea maps, or c/iaris. Where a land map
describes the nature of the ground, the roads, build-
ings, &c. in detail, it forms what is called a lopotg/rapliic
map, or plan. Some maps of the earth are made to
illustrate its natural history, and then we have a
geological, mineralogical, or ooianical map.
A description of the methods of constructing maps
scarcely belongs to, a work devoted to Useful Arts
and Manufactures; we must therefore refer the reader
to some special treatise on the subject.
MAPLE, (acer,) is a tree of which there are
numerous species, two of which are especially valued,
the one on account of its timber, the other on account
of its sugary ‘sap. The great maple,_ known also as
the sycamore andthe plane tree, is of rapid growth, '
and has close and compact timber, not liable to warp
or splinter. 'It prettilyz marked andmottled; it
takes a fine polish, and bears varnishing well; there,-

fore. it is much employed by the musical instrument-
maker. The best specimens, especially those from
Prince Edward’s Island, known as oiml’s-eye maple,
and mottled maple, are used for picture frames, and
other ornamental articles. Wooden platters, bowls,
&c. are made of maple, and as this Wood does not
contain those hard particles which are so injurious to
tools, it is employed as cutting boards; also, on
account of its not being apt to warp either with
changes of heat or moisture, it is employed for
saddle-trees, founder’s patterns, and many other useful
purposes.
Bird’s-eye maple has a peculiar dotted appearance,
similar to that whichis produced by knots in other
woods. This appearance is thus accounted for by
Mr. Holtzapffel :——“ On examination I found the stem
of the American bird’s-eye maple, stripped of its
bark, presented little pits or hollows of irregular
form, some as if made with an irregular punch, others
ill defined, and flattened like the impression of a hob-
nail. Suspecting these indentations to arise from
internal spines, or points in the bark, a piece of the
latter was stripped off from another block, when the
surmise was verified by their appearance. The layers
of the wood being moulded upon these spines, each
of their fibres is abruptly curved at the respective
places, and when out through by the plane, they give,
in the tangential slice, the appearance of projections,
the same as in some rose-engine patterns, and the
more recent medallic glyptographic, or stereographic
engravings, in which the closer approximation of the
lines at their curvatures causes those parts to be more
black, or shaded, and produces upon the plane surfaces,
the appearance of waves or ridges, or of the subject
of the medal. The short lines observed throughout the
maple wood, between the dots or eyes, are the edges
of the medullary rays, and the same piece of wood,
when examined upon the radial section, exhibits the
ordinary silver grain of the sycamore, (to which
family the maple-tree belongs,) with a very few of
the dots, and those displayed in afar less ornamental
manner. The piece examined measured 8 inches
wide, and 5% inches radially, and was apparently the
produce of a tree of about 16 inches diameter; the
effect of the internal spines of the bark was observable
entirely across the same, that is, through each of the
130 zones of which it consisted. The curvature of
the fibres was in general rather greater towards the
centre, which is to be accounted for by the successive
annual depositions upon the bark, detracting in a
small degree from the height or magnitude of the
spines within the same, upon which the several
deposits of woodwere formed. Other woods also
exhibit spines, which may be intended for the better
attachment of the barkto the stem, but from their
comparative minuteness they produce no such effect
on the wood as that which exists, I believe exclu-
sively, in the bird’saeye maple.”
MARBLE. The definition of this word is not very
exact, In a_ vague sense, the term marlles is applied
to numerous ornamental stones; but the typical or
calcareous marbles may be considered as such primi-
MARBLE; ‘
223
tive, transition, and purer compact limestones- of
secondary formation, as can be quarried in solid blocks
without fissures, and as are capable of a high polish.
A limestone which admits of being worked easily and‘
equally in all directions is called freestone, but a rock
of similar chemical composition, capable of being
worked in all directions, and also of taking a good
polish, deserves the title of marble. The whiter, or
more beautifully variegated the marble, the greater is
the estimation in which it is held: when fine, white,
and granular, it is valuable for the higher purposes of
sculpture.
Marble, in all its varieties, consists essentially of
carbonate of lime: it is characterised by its effer-
vescence with acids, its conchoidal scaly fracture,
and its translucence at the edges. It affords quick-
lime by calcination: it has a specific gravity of 2'7,
and it can be scratched with a knife. Primitive
marble is the most esteemed ; it is distinguished from
the secondary by the absence of organic remains, by
its granularly foliated character, and by its occurrence
among other primitive substances. The most cele-
brated statuary marble of ancient times was that of
Paros near Athens, and some of the finest antique
sculptures are wrought in it. The Italian marbles
are also highly prized, especially the milk-white marble
of Carrara or Luni, near the gulf of Genoa. An in-
teresting notice of the marble quarries of Carrara
appeared in arecent number of the Illustrated London
News, from which we select the following particulars:
-—The magnificent chain of mountains in which the
quarries are situated, juts out in an acute angle from
the Apennines, and forms a portion of the duchy of
Massa-Carrara. The aspect of these stupendous and
“ marble—hearted” heights, as seen from the sea-shore,
whence they are distant about four miles, is highly
picturesque. Almost destitute of vegetation, they
gleam in the sun-light like masses of brass, while at
intervals rugged and inaccessible peaks jut out sharply
against the sky, and appear to pierce into the clouds.
In numerous directions, about midway up the heights,
the eye is attracted by what seems to be a vast tor-
rent pouring down its resistless volume of seething
water into the valley; but which is, in fact, the shoot
of the refuse fiung out of the quarry immediately
above. On the flank of a few of the mountains, and
near their base, some stunted vegetation, consisting
mostly of dwarfed oaks and chestnut-trees, may occa-
sionally be seen; while nearer to the summit, in the
fissures and gulleys, a sickly and scanty herbage affords
sustenance to troops of goats. The quarries are ge-
nerally situated about midway up the mountain, and
although they are said to have furnished the ancients
with the material for building the Pantheon at Rome,
and more recently to have supplied nearly every
civilized country throughout the globe with their pre-
cious contents, to the extent of an export amounting
annually to an average of 410,000 tons, the workmen
are still employed upon the surface; and so little
effect has the labour of centuries produced upon the
general appearance of the mines, that they may be
safely afiirmed to be inexhaustible.

Of this export, the United States consumes nearly
the whole. Italy, France, and England confine thems
selves almost entirely to the statuary marbles: Eng-
land imports about 6,000 tons annually, but is steadily
increasing its demand. Russia employs these marbles
on her palaces and churches. The recent reduction
of the import duties, which were formerly very heavy
in some countries, cannot fail to increase the demand
throughout Europe. There is, however, still a heavy
export duty, which has, moreover, most injudiciously
been lately increased by the native government.
The quarries of Carrara contain four varieties of
marble, of which the most valuable is that used by
sculptors, the white granulm'lyfolz'ated limestone. This
was the favourite material of the artists of ancient
Greece, and still is so of modern Europe, on account
of its purity of colour, its delicate transparency, and
its granular texture, which renders it much more easy
to work than compact limestone. The two great
sources whence the statuary marble of Europe has
been procured are Paros and Garrara. The Parian
marble is the most pure, consisting almost entirely of
carbonate of lime, and is, consequently, softer, some—
what more transparent, and of a more visibly lami-
nated texture than that of Carrara, which is frequently
mingled in considerable proportion with granular
quartz. The latter has, however, no other rival as
regards either quality or durability. The other three
varieties obtained are the vez'rzea’ marble, equal as
regards texture to that already described, but tra-
versed by coloured lines which render it inappropriate
to the chisel; the mmez'om' or Sicilian, similar to
that produced near Messina; and the barclz'glz'o, which
is of a deep blue colour, but in formation precisely
similar to the white.
Some of the quarries may be explored with ease
and safety, but such is by no means the case with all
of them; while, in every instance, the paths by which
they are approached are dangerous to the uninitiated.
At times almost perpendicular, the way leads along
the brinks of stupendous precipices, where no path
can be discerned. The miners are a fine and hardy
race, remarkable for their robustness of constitution,
reckless courage, and unalterable good humour; nor
do the fatal accidents which occasionally occur tend
to lessen their gaiety; many a snatch of wild but
melodious song may be heard amid the clanging of
hammers, the report of gunpowder, and the crash of
falling stone. The hours of labour are from eight in
the morning to two in the afternoon, all extra work
being remunerated according to the time employed.
There being no springs in the quarries, and the diffi-
culty of ascent rendering it essential to the workmen
to avoid all unnecessary burthens, they drink rain:
water, which they obtain by excavating square holes
as reservoirs; their diet consists of polerzta, or bread,
and the common cheese of the country; and these
simple aliments, with the fruits of the season, compose
their whole nourishment. Inwine or coffee they never
indulge ; and yet they are capable of enduring a large
amount of labour. In working the quarries, the huge
blocks are first loosened from the mass by blasting,
2241
MARBLE.
after which wedges are applied until they are the-
roughly detached from the rock, when they are shaped
into oblong squares—with the exception of the sta-
tuary marble, of which the value is so great that the
masses are removed intact—then lowered to the'polr/gio,
or base of the mountain, whence bullock-cars trans-
port them to the Marina, where they are embarked.
When the quarry is situated so perpendicularly that
the stones incur risk of breakage from a too rapid
descent, they are surrormded by strong ropes, and
placed upon two parallel beams (or lizzi)~ of oak, be-
neath which lesser beams are arranged transversely.‘
A workman stands upon the block throughout its
perilous transit, and it is his duty to raise each of
these so soon as it is passed, and to hand it to another
man in front, in order that it may again be placed
securely upon the passage of the descending mass.
This is the most dangerous service performed by the
miners, as‘ it occasionally happens that the huge block,
after shivering for an instant upon its wooden sup-
port, yields to the impetus of its own weight, and
sliding from its oaken cradle, rushes headlong down
the declivity, rending the stout cables by which it is
bound, and crushing beneath its stupendous mass the
unfortunate individuals employed in assisting its de-
scent. Where the quarry is level, and nearer to the
base of the mountain, the lizza is dispensed with, and
the blocks are allowed to roll down unaided. At the
poggio the blocks thus collected are loaded upon strong
uncouth-looking bullock-cars, composed of three
parallel beams of oak, of which the centre one is
rather lower than the others; the animals are attached
to the carriages in numbers proportioned to the bulk
of the stone and the impediments which encumber
their path. It is a very common occurrence to see
ten 'yokes of oxen harnessed to one car, each guided
by a driver, whose business it is to avoid as much as
possible the ponderous masses which encumber the
ground ; and yet, at the first glance, it is impossible
to believe that they can ever hope to accomplish so
arduous an undertaking. In vain do the sturdy and
patient brutes strain to their task; the couples can
seldom or never be made to follow the guidance of
their leaders, who, by stumbling and straggling over
the rocky fragments among which they are impelled
by their drivers, partially level the path behind them,
as they are now dragged by the horns, now goaded by
the iron-shod staff, and now urged by the wild, half-
frantic cries of the men, whose shouts are re~echoed
by the rocks in deafening dissonance; but, swerving
to the right or left, how out for themselves a new
line of road frequently so impassable that, after having
bya mighty effort overcome some apparently impracti-
cable difficulty, the wretched animals stagger a few
paces, further, and then fall dead at their task. For
this evil no remedy has yet been found : the nature of
the ground, and the vconstant deposits of stone, ren-
dering it difiicult to construct a safer means of exit
from the poggio. This marble range extends over
many square leagues; the most productive, as well as
the most valuable quarries, being those of the statuary
marble, which do ‘not exceed 12 in all, the whole

of which are‘ the property of four or five of the princi-
pal families of Carrara; but the aggregate number
may be computed at 4:00, of which, between 4L0 and
-50 are in full work, and produce admirable stone;
while the number of workmen constantly employed
varies from 2,000 to 2,500. Legends of gnomes and
genii are rife among the miners, who, like their fellow-
labourers in every land, are imaginative and super-
stitious; and in the quarry of Fantiscotti a number
of names cut into the rock, and some roughly-carved
figures hewn upon its surface, are, objects .of peculiar
awe from the fact of their great antiquity, and the
absence of all tradition regarding their origin.
Beautiful secondary marbles occur in Derbyshire,
in Westmoreland, Devonshire, and Anglesea. Fine
varieties occur in Sutherlandshire and in the Western
isles of Scotland. Ireland boasts its Kilkenny marbles.
Much of the carboniferous and transition limestone
of Wales is also capable of being worked up into
agreeable dark marbles.
The various marbles have been classed, by Brard,
according to the several localities in which they are
found, and in each of such classes he introduces 8
subdivisions, viz. 1, Uni-coloured marbles; including
only the white and the black; 2, Variegated marbles;
those with irregular spots or veins; 3, Madreporic
marbles, presenting animal remains in the shape of
white or grey spots, with regularly disposed dots and
stars in the centre; 4:, Shell marbles, with a few
shells interspersed in a calcareous base; 5, I/ama-
c/zella marbles, entirely composed of shells ; 6, Uipolirz
marbles, with veins of greenish tale; 7, Breceia
marbles, formed of a number of angular fragments of
different marbles, united by a common cement; 8,
Padding-alone marbles, a conglomerate of rounded
pieces.
Specimens of marble, both in the. rough and manu-
factured state, were numerous in the Great Exhi-
bition: probably on no other occasion were so many
examples of this beautiful stone brought together.
The working of marble. into forms intended for house-
hold decoration involves the artistic skill of the
sculptor and the ingenuity of the mechanic. It is
remarked in the Jury Report of Class XXVII. that
“ Italy is pre-eminently the country where this ma‘
nufacture has been found most congenial to the
artistic feeling of the mass of the people ;” but that
of late years France, Spain, Portugal, and parts of
Germany and Belgium have employed for their own
use, and in their own style, many useful and valuable
marbles with which they abound; that in Derbyshire,
Devonshire, and Cornwall, the marble of those counties
has been employed in'house decoration, at a somewhat
high cost, ‘by yet at a much cheaper rate than it could
be supplied from abroad. The marbles of Ireland are
also getting into request. The green Connemara marble
was conspicuous in the Exhibition for its rich green
hue and great beauty. Among the marbles exhibited
some were from Greece and Asia Minor, from the
quarries worked by the ancients, now either exhausted
or concealed by rubbish. Among these were the true
Pariem of Greek sculptors, and some other fine white
_ MARBLE.
225
marbles‘: the dew oetz'eo, now a very rare black marble,
considered to be purer and better than the known
kinds; the rosso emtz'eo, a deep blood-red marble, with
veins and spots; the oerde antz'eo, a green and very
beautiful porphyritic brecchia; the girdle antz'eo, not
unlike the modern Sienna marble, of very rich yellow
tint. Many, if not all these colours, are closely
approximated by recent marbles.
The most important marbles of Derbyshire are the
black, the rosewood, the encrinital, the 9'Zt886t or dz'rd—
eye, and a mottled dark and light-grey kind, occa-
sionally containing numerous small corals. Of some
of these there are several varieties. In addition to
those found in the northern part of the county is one
of a beautiful red, resembling the rosso antz'eo, but it
can only be obtained in small blocks or lumps.
Of the above varieties bloc/e marble is of very fine
colour and texture; but large slabs, free from veins of
calcareous spar, are rare. The best quality occurs
in beds of from 3 to 8 inches thick; but some
beds are thicker. It is tough, and contains a good
deal of carbon, which imparts the colour. It is
greatly valued for inlaying, and it has even been ex-
ported to Florence, Malta, and St. Petersburg. Black
marble is used for vases, pedestals, chimney-pieces,
&c. It is occasionally ornamented by etching and
engraving, in which processes the polished surface is
' removed, and the brown colour of the rough marble
exposed. Powdered white lead is sometimes rubbed
into the etched surface, to increase the effect. The
French have a method of ornamenting marble in this
way by etching by acids deeply into the marble various
designs upon a properly prepared bituminous ground:
when the corrosion has gone sufliciently deep, the
cavities are filled up with hard coloured wax, pre-
pared so as to take a polish equal to that of the
marble, when cleared off. Drawings thus made on
black marble, and filled in with scarlet wax, after the
manner of Etruscan, have a fine effect, and are used
for tables, panelling, stoves, 850.1 At Derby they
succeed in exposing the brown colour without de-
stroying the polish, the effect of which is more durable
than ordinary etching. Rosewood marble, so called
from its marking resembling that of rosewood, is
extremely-hard and of close texture. The beds are of
considerable thickness, but the most beautiful part
of the marble is only about six inches thick. The
encrinital marble is the one in most extensive use; it
contains numerous fossils, consisting chiefly of the
broken stems of encrinites, often entangled in coral.
It may be obtained in blocks of large superficies, and
from two to two and a half feet thick. The russet or
bird-eye takes its name from its colour and appear-
ance,-—the shades, varying from light grey to brown :
it contains numerous minute encrinital fossils, and is
(l) The French artists also use thin polished plates of marble as a
substitute for ivory in miniature painting. The slices of marble
are cemented down upon a sheet of board paper, to prevent danger
of fracture, and to hold the marble firmly, and it is not affected by
heat or damp; whereas ivory becomes yellow; in hot climates is
liable to split or warp; and it can only be obtained of limited size.
Plates of marble 12 inches by 10, and {1; inch thick are prepared;
the smaller sizes are much thinner. These slabs can also be used
for oil paintings.
VOL. II.


found in beds of from 6 to 18 inches in thickness.
The dark and light mottled grey marble, called
Near/‘burgh marble, and the overlying bed, which is
coralline, can be obtained from one to two feet thick.
The marbles of Devonshire belong to an older geos
logical period than those of Derbyshire, the latter
being exclusively of the carboniferous limestone series,
underlying the coal measures and the millstone grit;
while the former are of the Devonian, or middle Pa-
laeozoic epoch. The Devonshire marbles are, in gene-
ral, less manageable than those of Derbyshire. The
most beautiful marbles of the county, especially those
near Plymouth, are described in the Jury Report as
_being"fossiliferous, brittle, and very apt to contain
veins and cracks.
The principal marble manufacture of England is in
Derbyshire, along the valley of the Derwcnt and the
Wye, from below Buxton to Derby. The machinery
for sawing and polishing was first established at the
village of Ashford, near Bakewell, in 1748, water being
the motive power. About the year 1810 similar ma-
chinery was erected at Bakewell; Both these works
are situated near the quarries. Within a few years
other works have been established at Buckland Hollow.
There are also other works at Derby.
The first step in the treatment of marble is the
dividing it into blocks or slabs of convenient size.
This cannot be done, as in the case of the ordinary soft
stones, with toothed saws of reciprocating motion.
The marble saw is a thin plate of soft iron, without
teeth, strained in a rectangular wooden frame. It
does not itself out the stone, but is the vehicle whereby-
the cutting is effected by means of sharp sandand
water continually supplied to the plate during the
sawing process. For a moderately soft marble a‘
coarse sand is employed, but for the harder kinds a
fine sand is used, such as can be obtained from road
sweepings where flint is much employed. These
sweepings are carefully cleansed by washing in per—
forated copper sieves, and all extraneous matters
removed. A piece of stone or gravel accidentally
getting beneath the saw would roll backwards and
forwards under the edge, and thus prevent its action
on the finer particles of flint, and consequently hinder
the cutting of the marble. The way in which the
sand and water are continuously supplied to the saws
is as follows :—A barrel of water is placed near the
block of marble, and a little above it. Near the
bottom of this barrel is a small hole, stopped by a
wooden peg; but as the withdrawal of the peg would
send down too large a stream of water, a groove is
cut in the peg, through which a minute streamlet
issues continually. This is directed to the required
spot by a slanting board, down which it trickles, but
not without carrying with it a small quantity of sand,
a little heap of which is placed near the path of the
Water, and is drawn forward in small quantities so as
to mingle with the stream. The workman uses for
this purpose a wooden stick, called a drzlp-stz'e/c, pro-
vided with an iron hook or an old knife blade fixed to
its extremity.
The sawing of blocks or slabs of moderate size is
Q
226
. MARBLE.
effected by hand; but where large masses have to be
acted upon, the operation is most effectually and
economically done by machinery. The weight of the
saw and frame is considerable, and supplies sufficient
pressure to enable the sand to penetrate the marble ;
but where the work ‘is done by hand, this pressure
sometimes causes the work of pushing the saw back-
wards and forwards to be a very laborious one. It
is therefore usual to have a counterpoise weight over
the saw-frame, with a cord and pulley, so as to reduce
the pressure to the required amount. ~ This is a relief
to the workman, but necessarily ‘diminishes the cut-
ting power of the sand.‘ The process of sawing is,
however, a ‘subsequent one to that of marking out
the block, which must be carefully done, so as to
allow'of the ‘greatest number of parallel slabs being
cut from it. For this purpose, the block is first
shifted on rollers into the position in which it is to
be sawn, and then mounted on square pieces of wood
called s/cia’s. The lines are drawn with a soft piece
of black slate called b'laels experience alone can teach
the best and most economical way of doing this. All
the lines are carefully examined before the sawing
commences, a plumb-line being used to determine
their accuracy, and this being ascertained, the top
lines are chased, or cut in about %th of an inch
deep with a narrow chisel, to form a groove for the
saw and its accompaniment of sand and water. The
end lines are also chased in the same way, ‘to avoid
the danger of getting the lines obliterated during the
_ progress of the work.
The saw, Fig. 1382, is from 5 to 10 feet long, and
from 41‘ to 5 inches wide, but its thickness is only
from %th to %th " of ‘an inch. It is fastened to
the- upright side of the frame at each end by an

0-1 u '1: ' > “. 4._-—————--¢‘ _-
v ‘in’ ' v V I V _ ‘V




Ap'l
Fig. 1382.
ir'hn pin, and is kept distended by a wooden stretcher
called the pole, placed about a foot from the top of
the frame, and resting at each end against a loose
block of wood called the lols-ier. The upper ends of
the frame are drawn together by a chain made of
looped iron rods, and the tension is given by a double
screw which has holes for a lever, and is therefore
capable of being worked with great power, so as to
compress the heads of the frame to the utmost, and
so distend the saw. The lower end of the frame on each side‘serves as a handle, by which the saw is T
made to traverse backwards and forwards by the.
workmen-“The depth to which the saw can penetrate
inthe stone'is regulated'by the' distance apart of the
blade and the pole, ‘therefore the pole is placed at
different heights from the blade according to the work
in hand. 'All'parts of the ‘frame are capable of being

detached, so that poles, saws, and leads (as the'sides
of the frame are called), can all be changed at plea-
sure. In commencing the work, great care is required
to keep the saw perfectly upright, for if it once takes
a direction oblique to the black lines previously
drawn, the slab cannot fail to receive injury; for,
although the saw may be speedily righted and the
vertical line resumed, yet at the place where it devi-
ated, a hollow will be produced called a gall, which
must be rendered level with the rest of the slab, by
much subsequent labour in grinding away the elevated
parts. This reduces the thickness of the slab, and
perhaps renders it less fit for the purpose to which it
is to be applied. The saw is‘ usually chosen about
2 feet longer than the block to be ‘cut, and when 2
small blocks are to be divided, they are often placed
end to end, and both out through at once. If sub-
divisions of the slab are needed, these are cut from
the larger slab on a bench with a stone or marble
surface called a milling-led. Here the lines are
marked and chased on the slab, and the cutting is
effected by a grab—saw, Fig. 1383. This ‘is a blade of
iron, not extended in a frame, but clamped at the
upper edge between 2 pieces of wood. This saw

6 (‘J 6 6 ®

“MA-MM
Fig. isss.
must be shorter than the block of marble to be, oper-
ated upon, because it rapidly wears away; and if the
ends projected, as in the former case, the wear would
be very unequal and the blade, hollowed out in the
middle, would soon become useless. On the other
hand, if the grub-saw is much shorter than the cut,
the tendency is for it to wear rounding in its length,
to counteract which, notches are sometimes filed in
the blade, which are supposed to make the wear of
the saw more equal, and at the same time to allow
the sand and water to reach the bottom.
When the ‘slabs have been by this means reduced
to their proper dimensions, they are laid on the rub-
bing-bed, and ground fiat by means of a smaller slab
of hard stone, called a manner. This, with sand and
water as a grinder, is worked over the entire surface
of the slab, by means of a ‘handle, which for small
runners may be vertical or fixed at an angle; but for
large runners must be of considerable length, and
made to grasp the rumier by means of an apparatus
of wood, and a loose ring called a'lzoolr. But the
runner is in some cases made of iron instead of stone,
and so, the handle is passed through holes in its
projecting ends. Whether of stone or iron it is
pushed backwards and forwards in all directions,
working the sharp sand and water, with which it is
plentifully- supplied, over the surface. As the marble
approaches completion, the sand is changed for finer
kinds, which—are gradually substituted until at last
the best and finest sort, called silver-sand, is applied to
give the last smoothing effect, preparatory to polish-
ing, though some of the latter processes are often
included under this head, and called grounding.
MARBLE.
'227
The-polishing ‘of marble is differently carried on,
according to the nature of the work. For small slabs
or objects of an ornamental kind, the highest degree
of finish is requisite. Polishing is commenced with
pumice-stone and water, and with snake-stone, after
which various rollers or rubbers are employed. If
the object be large and flat, the rubber may be a
wooden block faced with thick woollen cloth, or a
mere bundle of woollen or other rags compressed in
a rectangular iron frame, and moved about with a
handle. For smaller works, rollers of woollen cloth
or list about 3 inches in diameter are employed.
Some of these are charged with flour, emery, and a
slight degree of moisture, which produces a kind of
greasy polish uniformly over the surface. A similar
roll of cloth, charged with putty-powder and water,
completes the process. In some of the most delicate
works, crocus is used intermediately between the
emery and the putty—powder, but this is only with
dark-coloured marbles. The marble is carefully washed
after each operation, to prevent the scratching of the
surface, which would result from the mixing of difie-
rent particles. Some workmen give a final rubbing
up of the work with coarse linen rags.
It is obvious that in the case of mouldings in
marble, the methods of cutting, grinding, and polish-
ing, must vary from the above. A pattern in card-
board is taken of the exact form of the moulding
‘about to be ex’e'cuted, and a counterpart is also pre-
pared, either in sheet metal, or in wood. An outline
of the moulding is then drawn on the end of the piece
of marble to be operated on, and the form is roughly
made out, either by chipping, or by toothed, or grub-
saws. Lines are then drawn on the face of the work,
the more distinctly to make out the several parts of
the moulding. These parts are worked first as square
fillets and small chamfers, and then rounded with
small chipping ehisels, according to the shape of the
mould, which is constantly referred to as a pattern-
The surfaces are then ready for grinding, which is
effected by means of stone or iron rubbers, shaped so
as to fit the several curved or square edges of the
moulding, and charged with sand of various degrees
of fineness. The smoothing and polishing are carried
on with small slips of grit-stone, and snake-stone,
followed by putty-powder, on the ends of soft deal
sticks, then rubbers of worn-out felt, and finally linen
rags and putty-powder.
For circular works which admit of turning the
following is the method adopted by Messrs. Hall, of
Derby, and described by them in the “ Jury Report,”
already referred to :——“ Having chosen a piece of
marble about the size required, and free from veins,
vents, &c., to which black marble is very subject, the
first process, is to level one face, and with a pair of
compasses strike a circle round the outer edge, then
with a mallet and pointed chisel, work it roughly to
a circular form. It is then ready for the lathe, and
being fastened with a resinous cement to an iron
chuck, it is screwed to the lathe-spindle, and a very
slow motion given to it. The only tool used is a bar
of fine steel about 30 inches long by %inch square,

drawn to a point, and well tempered. This is forcibly
applied to the marble, which it reduces to the proper
form by slowly spelehing off small pieces. After the cor-
rect outline is acquired with this tool, it is ready for
the grinding process, the first being to apply a piece of
coarse and hard sandstone with water, (the lathe now
having a rapid motion) until all the tool marks are
ground out. A finer piece of sandstone is then used
to remove the coarse scratches of the previous one,
and so on with a few other and still finer stones,
until all the scratches are quite obliterated. This
prepares it for polishing. A piece of cotton cloth,
washed quite clean, and well rubbed with flour emery
is applied to the marble, and polishes it to a certain
extent. A similar piece of cloth is then rubbed over
with putty-powder (white oxide of tin), which gives
a very high polish.”
For several years past the working of marble byhand
has been in great measure superseded by the use of
machinery, which not only expedites the various pro-
cesses, but gives greater exactness, and admits of a
more economical treatment of the material. In saw-
ing the blocks asunder, the construction of the saw
already described is closely followed, but the frame
is much larger and stronger, and is so arranged as to
guide the action of a number of saws fixed in a
vertical plane parallel to its length. Fig. 1384: will
convey a general idea of the horizontal sawing-machine
for marble, patented by Mr. James Tulloch in 1824.1, .
and thus described :‘-—The iron frame-work of the
machine consists of 4: vertical posts strongly con-
nected together at the top and bottom, to form a
stationary frame from 10 to It feet long, 4: to 5 feet
wide, and 8 to 12 feet high, within which the block
of marble to be sawn is placed. The 2 upright
posts at each end of the stationary frame have, on
their insides opposite to each other, perpendicular
grooves, within each pair of which slides up and down
a square vertical frame: to the lower end of each‘ of
these slides is affixed a spindle, carrying 2 guide
pulleys, or riggers, upon which the horizontal saw-
frame rests, and is reciprocated backwards and for-
wards. The saw-frame is thus traversed within the
fixed framing, and supported upon the. 4 guide
pulleys of the vertical slides, which latter are them-
selves suspended by chains coiled upon 2 small
drums placed overhead. On the same spindle with
the drums is a large wheel, to which a counterpoise
weight is suspended by a chain. The weight of the
counterpoise is so adjusted as to allow the saw-frame
to descend when left to itself, and which thus supplies
the necessary pressure for causing the penetration of
the saws. The saw-frame is made rectangular, and
from 2 to 3 feet longer than the distance between the
vertical slides, in order to permit of the horizontal
traverse of the saws, which is from 18 to 20 inches.

(1) Mr. Tulloch’s machines are described in the “ Repertory of
Patent Inventions,” for 1836: but the date of the patent is 1824.
They are also described in every clear manner in the third volume
of Holtzapfi'el’s “ Mechanical Manipulation.” Our figures are
from, the machines at the London Marble Works, Escher-street,
Millbank, which, with the permission of the proprietors, we were
allowed to examine and copy.
Q2
223
, ‘MARBLE.
ing the position of the neighbouring blades. The
.. ‘5 Q‘
To allow‘of the blades being fixed in the frame with r
the power of separate adjustment, every blade is
secured by rivets, in a clamp or buckle at each end ;
the one extremity of the buckle embraces the saw,
the other is made as a hook; the buckle at one'end of
the saw is hooked upon a horizontal bar, fixed across
the end of the saw-frame, and the opposite end of the
frame has a groove extending its entire width,
throughwhich a separate hook, provided with a ver-
tical tightening wedge,- is inserted for. every saw,
which thus admits of being replaced without derang-
distances between the saws, and their parallelism with
the sides of the frame, are'adjusted by means of iron
blocks, made of‘ the exact thickness required in the

slabs of marble, the .blocks and blades are placed





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Fig. 1384. HORIZONTAL sxwrxe MAcurN'E.
alternately, and every blade is separately strained by
its tightening wedge until it is sufficiently tense ; the
blocks are sustained between 2 transverse bars,
called gage-oars, and are allowed to remain between
the blades to give them additional firmness. The
.traverse of the saw-frame is given by a jointed con-
necting rod, attached by an adjustable loop to a long
vibrating pendulum, that is put in motion by a pair
‘of -:connecting rods, placed one over the other, and
leading from two cranks driven by the engine.
three 'comiecting rods admit of vertical adjustment on
_the pendulum.
P placed intermediately between the other two, but
itsexaet position is regulated by the height at which
All
The connecting rod of the saw-frame
the saws- are, working, as it is suspended by a chain
“and counterpoi'se weight, which allow it to descend
gradually downwards on the pendulum with the pro-
gress of the cut, so as always to keep the connect-
5...,”
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ing 'ro‘d nearly horizontal. Sometimes 4. of these
sawing machines are grouped together, with the
driving shaftiand pendulums in the middle, and so
arranged that each pair of frames reciprocate in.
opposite directions at the same time, in order to
balance the weight and reduce the vibration. Various
modifications in the form and arrangement of saw--
frames have been from time to time adopted, but
they are not of importance to the general principle.
Much difficulty was experienced in supplying me-
chanically to the whole of the ‘saw—blades in these
machines’ a simultaneous flow of sand and water,
but this difiiculty has now been overcome by means
of an iron cistern or trough filled with water, extend-
’ing across the width of the saw-frame, and having
about 20 small cocks arranged along each side.
From these
cocks the water
flows in minute
but constant
streams, which
are received
below in little
boxes, and con-
veyed along a
grooved trough
filled with sand.
The grooves or
iarmels (for they
'6 partially
covered,) take a
curved form, as
shown in Fig.
1385, and slope
downwards, by
which means the
equal flow of the
' sand and water
is secured. The
water flowing
through the tun-
nels constantly
undermines the
sand on the con.
vex side, which is open for its admission, and thus
without the obstruction which might occur in open
grooves, and without the danger of the water making
for itself a channel,
and leaving the sand
behind, the desired
object is effectually
secured.- Fig. 1385
represents the form
of the grooves at the
bottom of the sand
trough.‘ .
The Sewing-‘machines above described are set in
action in the following manner :-—The saw-frame is
raised by means of a Windlass, and the suspending
chains attached to the vertical frames, and the block
of ‘marble is then wheeled into its position beneath




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Fig. 1385. '
them, and adjusted by wedges. , The saws are then;
MARBLE.
229-
lowered until they rest upon the" block; the counter;
poise weights are adjusted, and the mixed sand and
Water allowed to run upon the saw-blades, which are
put in motion by attaching the connecting-rod to the
pendulum. The sawing then proceeds mechanically,
until the block is divided into slabs, the weight of
the saw-frame and connecting-rod causing them gra-
dually to descend with the progress of the cutting.
To allow the sand and water to flow readily beneath
the edges of the saw-blades, the horizontal frame is
lifted slightly at the end of each stroke; for which
purpose, the lower edges of the frame which bear
straight upon the guide-pulleys for nearly the full
length of the stroke, have a short portion at each
end made as an inclined plane, which on passing over
the guide-pulleys, lifts the frame just sufficiently to
allow the feed to flow beneath the saws.
~ When the marble has been sawn into slabs, it is
cut up into narrow pieces for shelves, 860., by means
of circular saws, in a machine called a ripping-ted,
Fig. 1386. It consists of a bench 12 or 14 feet long,
6 or 7 wide, and 2,1, high ; upon the top of the bench
are two rails, upon which a platform mounted on

RIPPING BED.
Fig. 1386.
pulleys is drawn slowly forward by aweight. The
circular saws have smooth edges, and are fed with
sand and water: they are mounted on a horizontal
axis, which revolves about 9 inches above the plat-
form, and to prevent the saws from turning round
upon instead of with the axis, a projecting rib or
feather extends the whole length of the axis. The
saws are circular plates about 17 inches in diameter:
they are clamped between two collars about 6 inches
in diameter, fitted so as to slide upon the spindle, and
be retained at any part of its length by side screws.
The slab of marble is imbedded in sand upon the
platform, and the edge of each saw is surrounded on
one side with a small heap of moist sand. The saws
are set in motion so as to cut upwards, and the plat-
form is slowly traversed under the saws by the weight
which keeps the slab of marble constantly pressing
against the edges of the saws. The slab is raised to
the required height for cutting it through by means
of a layer of sand spread evenly over the platform,
and as the saws diminish in diameter by wearing

away, "the layer of sand is increased in‘ thickness.-
By a recent improvement, the axis of the saws is
mounted in a vertical slide adjusted by a rack and.
pinion, by which means the saws can be raised or
lowered to the exact distance required for cutting
through the slab. . '
Circular slabs for table tops, &c., are brought into
form by means of revolving cylindrical cutters. For
disks of small diameter, such as those
used in tesselated pavements, the
cutters are made as hollow cylinders
of sheet-iron of various sizes, each
attached by screws to a circular disk
of cast- iron, as shown in section,
Fig. 1387. Each cutter is screwed to the lower
end of the spindle, Fig. 1388. This spindle works
in cylindrical bearings, and can be elevated or depressed
as required. It is suspended
at the upper end by a swing
collar attached to a connect-
ing-rod jointed to the middle
of a horizontal lever. The
weight of the vertical rod
gives the pressure required
for the cutting, and the whole
can be raised fromv the hori-
zontal table, on which the
work is adjusted, by means
of a rope attached to the
end of the lever passing
over a pulley. Wide notches
are made in the lower edge
of the cutter to allow the
sand and water freely to
Fig. 1387.
\
swimmer...
enter. For large disks,
6 feet in diameter, for ex-
ample, the cutters are
arranged as shown in Fig.
1389. A circular plate
screws into the extremity of
the vertical spindle, and to this plate is bolted a
wooden cross. The cutters e e, which are detached
plates of iron of various dimensions, according to the
size of the work, are
each riveted to a
clamp passing through
a radial groove near
the extremity of each
arm, and retained by a wedge. Every dif- ;
ferent diameter re
quires a different
curve in the cutters.
In the grinding of
works of small or
moderate size, laps of
cast-iron, called sandg
ing-plates, are used,
varying from 6 to 14
feet in diameter, and mounted upon vertical spindles.
Across the face of each plate, and nearly touching it,

Fig. 1388.

Fig. 1389.
230
MARBLE;


‘ illll
are fixed one or two stops, which prevent the
work being carried round by the plate, and also act
as a guide to ensure the work being ground square.
These stops consist of strong square bars of wood
faced with iron. The face to be ground is placed
fiat upon the lap, with the side of the piece of
marble in contact with the guide-bar. Water is
allowed to drip upon the plate from a cistern above,
and small quantities of sand are sprinkled on it as
required, and the workman exerts a certain pressure
upon the work, occasionally shifting its position to
prevent the formation of ridges. When two pieces
of exactly similar size. are to beground on the face
and edges, as for the upright sides of a chimney-
piece, the two pieces of marble are cemented together
back to back, with plaster of Paris (a plan called
lining), and the pair are ground as one piece on
all four ‘faces. Some of the large grinding plates
accommodate 4: to 6 men, in which case 2 or 3
guide-bars are fixed across the plate. To protect
the men from the wet which is whirled off by the
centrifugal force of the plate, a rim is fixed above
the level of the lap, or where the work is too
large to admit of this, each man stands within a kind
of trough made like a box, but without any top or
back. ,
For large slabs of marble or stone, Mr. Tulloch’s
grinding-ted may be used with advantage. In this


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tion, partly eccentric and partly rectilinear, so as
continually to change their relative positions. The
machine consists of a frame about 9 feet long, 6 feet
wide, and 8 feet high : about 2 feet from the ground is
mounted a platform that is very slowly reciprocated
horizontally for a distance of from 1 to 2 feet, accord-
ing to the size of the slab, by means of a rack and
pinion placed. beneath and worked alternately in both
directions. Above the platform are fixed, vertically,
two revolving shafts, having at their upper extremi-
ties horizontal toothed wheels, of equal diameter,
which are driven by means of a central toothed wheel
hinged on the driving shaft. The two vertical shafts
are thus made to revolve. at equal velocity, or turn for
turn, and to their lower ends are attached two equal-
cranks, placed parallel to each other, the extremities
of which, therefore, describe equal circles in the same.
direction. To these cranks the iron grinding plate or
runner is connected by pivots, fitting two sockets
placed upon the central line of the plate. The cranks
are made with radial grooves, so that. the pivots can
be fixed by wedges at any distance from the centre of
the cranks. When the machine is put in motion the
grinding plate is thus swung round bodily in a hori-
zontal circle of the same diameter as the throw of the
cranks, which is usually about 12 inches, and con-
sequently every portion of the surface of the grinding
plate would describe a circle upon the surface of the
slab if the latter were stationary.
But by the slow rectilinear move-
ment of the platform the slab is con-
tinually shifted beneath the plate so
cycloids, in a different position; and
it is only after many revolutions of
the cranks that the same points of
the surfaces of the grinding plate
and slab are a second time brought
in contact. The grinding plate is
raised for the admission of the slab
by means of 4: chains suspended
from a double lever, and attached
to the arms of a cross secured to


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i i like a scale pan. For slabs that are
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much thicker or thinner than usual,
the principal adjustment is obtained
by the removal or addition of sepa-





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Fig. 1390. GRINDING- BED.

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machine, an elevation of which is shownin Fig. 1390,
the slab to be ground is placed horizontally upon a
moving‘bed, and the grinding produced by sand‘
and water, by means of a large flat plate of iron rest--
ing upon the surface of the slab. “.The two surfaces
are traversed over each other with a compound mo-




the proper height. Slabs that are
too large to ‘be ground over the
Q whole surface at one operation, are
shifted once or twice during the
. grinding.’J The weight of the hori-
zontal, plate supplies the pressure required for grind-
ing; and the pressure can be regulated if necessary
by a counterpoise weight attached to the double
levers. The sand and water required for the grind-
ing is thrown upon the grinding plate, which is
lit-l"
all
-' I l the platform to support the slab at
l
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pierced with a number of holes, and is surrounded
as to place the circles, or rather the.
.the centre of the upper surface of
MARBLE.
231
by a ledge, so as to form a kind of shallow tray. I
The sand and water find .their way beneath the‘
plates through these holes, and gradually work their
way out at the edge.
Straight mouldings in marble are wrought by a
machine similar in construction to the ripping-bed,
Fig. 1386, only instead of thin cutting disks of sheet-
iron, the grinders are solid cylinders of east-iron
turned to the counterpart forms of the required
mouldings.1 The forms of some of these grinders are


Fig. 1391.
shown in Fig. 1891, in which the outlines represent
the grinders, and the shaded part the form of the
moulding produced by them. Mouldings in the
edges of narrow slips are sometimes produced in
pairs, the two pieces being cemented together side-
ways as one block, which is placed edgeways on the
machine. Each grinder has a central hole for the

axis of the machine, and the vertical adjustment of
the axis mentioned with re-
ference to Fig. 1386, is in this
machine a necessary accompa-
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scnted a section of one of
these grinders for circular - 21;“
work. The larger circular : m “I
mouldings, such as the base
of a column, are turned after
the manner described by
Messrs. Hall, already quoted.
Circular works are usually "
polished in the lathe, but
rectilinear works in a polish-
ing-bed, Fig. 1392. Above
the bench is fixed a crank driven by the engine:
from this a connecting-rod leads to an iron swing
frame, working as a pendulum, placed 2 or 3 feet
from the end. The swing frame consists of two
niment. Small flat circular ...__...=,__,_.:;_i“ ~~ P mouldings are formed by ,1,’ _ L . . E H grinders adapted to the figure _/~ 1' t. required, and worked by the / 55 ,5. L ,h I" " vertical spindle, Fig. 1388, at as...‘ I \_ .;} Hpll'jhjrirmir" the bottom of which is repre-
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(l) The methods of cutting in the ripping-bed and grinding by
means of solid cylinders, form the subject of lVIr.G.W.Wilde’s patent,
sealed 15th April, 1833. This patent is declared to be “ for the
sawing of marble or other stone by means of a revolving circular
metallic plate, smooth or not serrated on the face or edge, and
applied with sand and water as is done with the straight saw; and
also for making on the surface or periphery of a metallic or wooden
cylinder or wheel, the converse of the intended moulding or
grooving, by means of which a series of mouldings or grooves can
be wrought on a surface of marble or stone at one operation with
sand and water, and in like manner polished with putty, bufi‘, 01'
pumice-stone, or other polishing material.” In 1822, Sir James
Jelf patented a combination of machinery for cutting parallel
mouldings upon marble slabs. Brown’s machinery is of still older
date. ‘ -
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rods moving upon centres above, and carrying near
‘their lower extremities a horizontal bar extending the
entire width of the bench, and to this bar are attached
as many separate iron rods as there are rubbers to be
employed at one time; each rod is jointed to its own
rubber, which for flat surfaces is a block of wood
about 2?; feet wide, covered with thick felt, and
charged with emery in the first stages, and putty-
powder for finishing. The rubbers are shifted across
the width of the slab by sliding them to another posi—
tion on the horizontal bar of the pendulum frame,
and the platform of the machine is traversed endways
by a chain and drum, or a rack and pinion, so as to
expose the work equally to the action of the rubbers.
For rectilinear mouldings elastic rubbers are used:
they are made of coarse cloth, such as old sugar-bags
cut into strips about 6 inches wide, folded lengthways,
and nailed through the middle of the fold close toge—
ther to a block of wood, so as to present a surface 8
or 9 inches wide, composed of the edges of the cloth,
which penetrate into the angles of the mouldings.
Various other patents have been taken out for
improvements in machinery for cutting marble and
stone, one or two of which maybe noticed.- And, first,
with respect ‘to the usual method of cutting marble
with the saw, Fig. 1382. The heavy construction





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Fig. 1392.
POLISHING BED.
of this saw renders the work very laborious, and much
skill and judgment are required to drive it upright
and true. According to Mr. Hutchison, marble cut
by steam power produces so rough a surface, that
what is gained in speed and labour is counterbalanced
by'the labour required for closing the surfaces for the
polisher: extra capital is also required for keeping
an assorted stock of marble slabs of all dimensions
and thickness. “ Stone is hardly ever cut or sawed
by steam power, as it is generally used in more solid
substances than marble; and also on account of the
probability of the saws coming in contact with fiints,
through which the saws could not cut; and hard
coloured marbles are also cut by the old method of
hand-sawing, owing to shells and other hard matter
found_therein. Good statuary marble is, I believe,

i232
MARBLE—MARBLES.
never out by steam-power, as the vibrating movement
stuns and renders the surfaces of the slabs coarse.”
Mr. Hutchison in 184%3 patented an invention
which he calls a saw'guide, which is said to produce
better work, and to enable any labourer or strong
youth to drive one‘ or more saws with ease. Fig. 1393
is an elevation, and Fig. 1394 a plan of the saw as
mounted for work. A is the frame-work, :e the roof
or covering, 0 the saw-guide, which admits of being






.Fig. 1393.
raised or lowered by screws D, and also adjusted
laterally by screws E. The saw—guide rests upon, and
is guided by the cross-rails x resting upon the
movable pins z. 13" is the frame-saw of the usual con-
struction for hand-sawing, and in being moved back-
wards and forwards it is guided by the saw-guide o.


Fig. 1394.__
G is a movable pulley with a suspended weight to
relieve the heaviness of the saw or saws and tackle, to
allow the sand to: run under the saw—plates, each
pulley being attached to a ring which slides freely on
the bar M above. H and I are movable rails of wood
resting on iron pins 2' 5 these rails have holes to allow
vertical screws, 1), to work through; they raise or
lower the saw—guide 0. J J are friction rollers to the
saw-frame, to facilitate its movement between the
saw-guide.
In 1843 Mr. C. J. Wollaston took out a patent
for improvements machinery for cutting- marble and
stone, whiclr We notice for the sake of describing his
method of‘ cutting pipes or tubes of that material.
Fig. 1395 shows a front view of the machine, and
Fig. 1397 a‘ side elevation partly in section, Fig.
1396 two plans thereof. AA are two pillars which
act as guides to the plates B c, which are combined
together by means of screws DD and nuts FF. On
the plate B is placed the block of stone or marble
to be cut, and' E is a plate brought to' press on the
upper end of the block to keep it in its place. The
frame consisting of' the plates B o, and screws ID is
suspended from the cross—head or top plate G, by
means of‘ the screw H, and this screw is made to
descend by the action of the cog-wheel I, which turns
in a suitable bearing in the_ cross-head or top plate,

.and a hollow screw is formed through the nave'of the
wheel to fit the screw H: hence by turning the wheel
I, the frame with the stone or marble descends :
motion is given to the wheel I, by means of the pinion
J, aiiixed on the shaft ‘K: the pinion J takes into and
drives the cog-wheel 1, which moves on the axis 2,
and to the wheel 1 is afixed the pinion 3, which takes
into and drives the cog-wheel I; the shaft K receiving




.1
Fig. 1396.
Fig. 1395. Fig. 1397.
motion from the driving shaft L in the following
manner: M is a series of pulleys to receive a strap
from a steam-engine or other power; on the shaft L
is aflixed the bevelled toothed wheel N, which takes
into and drives the bevelled tooth wheel 0, aflixed to
the shaft K; and on the shaft K is afiixed the pinion
P, which takes into and drives the cog—wheel Q affixed
to the axis n, which carries the cutter tube s, which
tube is aflixed to the axis and turns therewith. On
the upper end of the tube are attached a series of
cutters, and as these revolve with the tube, the stone
or marble is cut, and as it is cut it is lowered; the
inner part cut out descending into' the tube, will
serve, if desired, for making another tube in a similar
manner, -
MARBLES are made in large quantities for boys.
Some of them are formed of potter’s clay, glazed and
burnt in a furnace ,- others are made of marble and
alabaster, but the greater number are of a hard cal-
careous stone, which in Saxony is prepared in the
following manner :-—The stone is broken into square
blocks with a hammer, and rounded into spheres by a
mill; for which purpose they are placed 100 or 150 at
a time upon a fixed slab of stone containing a number
of ' concentric grooves or furrows. Above this stone
a flat slab or block of oak of the same diameter, sup-
ported by a lever, is turned round by the power of the
mill, and while in motion small threads of water are
made to enter each of the concentric grooves, whereby
the wood is prevented from heating and the balls are
rounded and polished. In about 15 minutes the
marbles are finished and are fit for sale. Immense
quantities are exported to India and China. A mill
MARBLIN GI
238
with 3 turning blocks will ‘manufacture 60,000
marbles per week.1L
MARBLING is a very curious art, by means of
which the edges of books and the surface of paper are
covered with various peculiar devices. This subject
has almost entirely escaped the notice of writers on
the useful arts. An account of it as practised in
Paris, was published in the year 1828, in the Die-
tz'orzrzctlre Z'eelmologz'gue, and translated into Gill’s
Technological Repository about the same time. We
will first give an abstract of that paper, and then
state the details of the art as witnessed by the
Editor.
The colours are arranged by apeculiar sort of brush
upon the surface of a solution of gum, and the sheet
of paper or book edges is placed upon this in such a
way as to cause the adhesion of the colour without
disturbing the pattern. When the sheet has been
dried it is waxed and glazed. The finishing of the
edges of books is generally left to the bookbinder.
The solution of gum forming what is called the
couch or bed is prepared by adding 3 ounces of gum
tragacanth to half a pailful of water, and stirring it
frequently during 6 days. This solution will serve
for marbling the edges of 4100 volumes. A much
stronger solution of gum is also made in order to
increase the thickness of the couch when required.
Some hours or at most the day before the marbling,
a quantity of ox-gall is beaten up with its own weight
of water, and a solution of camphorated spirit (formed
by dissolving 18 grammes2 of camphor in 25 grammes
' of alcohol) added thereto, beaten up thoroughly, and
the whole filtered.
' The wax is prepared in the following manner:
yellow virgin wax is to be melted in a glazed earthen
vessel over a slow fire: when thoroughly melted it is
removed from the fire and a quantity of turpentine
stirred in until it is of the consistence of honey. A
drop of the mixture is put upon the thumb nail from
time to time and allowed to cool, and in this way the
proper consistence is udged of.
The colours employed are the ochres and such
animal and vegetable matters as will float upon the
gummed surface. Naples yellow, or the yellow lake
from weld, supplies yellow. Golden-yellow is made
with terra dc Sienna unburnt. . Indigo supplies blues,-
earmine, or carmine lake, red; umber is used for
trozon; ivory black for black; white is produced by
the gall; green from a mixture of blue and yellow;
violet from yellow and red. The colours must be
ground very fine with a muller- upon a porphyry or
marble slab, with the prepared wax and water, and a
few drops of alcohol. When well ground a small
portion of the colour is taken up with a palette-knife
and allowed to fall upon the surface of the gummed
water. If of the proper consistency, the colour is
collected into an earthen pot for use.
The solution of gum is prepared for the marbling
vat in the following manner :-—-200 grammes of alum

(1) Archives des Découv. et Invent. 1826, quoted in Gill’s Tech-
nological Repository, 1828.
(2) The gramme is equal to 15'“ grains.

in fine powder are added to as'much of the prepared
gum as will cover the bottom'to the depth of an inch,
and well beaten up until dissolved. A spoonful or
two of this solution is poured into a small conical
vessel and a drop of the colour allowed to fall
upon the surface, when it is to be distributed in.
a circular form by means of a small rod. If it
extend well and form a good spiral figure without
dissolving in the gum, the solution is sufliciently
strong; but if the colour will not turn, the gummed
water is too thick, and water must be well beaten
up with it: if, on the other hand, the colour
spread too much. and dissolve in the gummed
Water, then some of the stronger prepared gum must
be added. When, by repeated trials, the gum water
is found to be of the proper consistence, it is to be
passed through a sieve into the marbling vat, so as to
form a stratum at the bottom tothe depth of one
inch. The colours, too, being ground and thickened
with the prepared wax and ox—gall so as to be of the
proper consistence for working, a quantity of gall is
first spread over the surface of the gummed water.
The thinnest colour that is to be used is then thrown
on; then a colour which is somewhat thicker; then
a third thicker still, and so on, the thicker colour
pressing upon the thinner immediately below it and
causing it to spread. When all the colours are
thrown on, the pattern is worked out: if a volute or
spiral be required, a rod is held upright in the hand
of the operator and carried along amongst the
colours in a spiral course. The colours are thrown
on with a kind of pencil or small broom, prepared as
followsz—twigs of osier about a foot long and two
lines thick are used for the handles, and along the
smaller end of the twig are tied with packthread, for
each‘ pencil, about 100 hog’s bristles of the greatest
possible length. With these pencils the operator
throws on here and there over the gummed surface
the first colour; then in the midst of that the
second; then the third, and so on; so that when the
colours spread, the different sets approach each other:
the pattern is then formed with the stick in the
operator’s hand. For example, suppose it were re-
quired to produce the pattern known as t/lepartrz'dge’s
eye ; the operator prepares two tints of blue with
indigo, which we will name No.1 and No. 2, the
latter containing a larger portion of the prepared
gall than No. 1. He first throws on carmine lake;
secondly, the terra de Sienna; thirdly, the indigo
No. 1; and fourthly, the indigo No. 2 ; he next jerks
on two drops of turpentine. The blue, No. 2, last
laid on extends all the other colours and affords a
clear blue in spots, an effect which is due to the
action of the turpentine upon the colours last thrown
on. The marbler then takes 8 or 10 volumes, and
commences by marbling their front edges, which he
first prepares by laying the back of each volume
upon a table, turning back the boards, and applying
a clamp, which he attaches by screwing its jaws
close, and thus levels the front edges, which are
marbled by being plunged into the vat. Having
marbled the front edges of the 8 or 10 volumes, he
234i‘.
MARBLING.
loosens the clamps, and strikesup the ends so as to
make them all enter the gummed water at the same
level: he clamps them again and dips them as before.
The marbler can vary his patterns to any extent;
they depend upon his taste in arranging the colours,
and upon the number of colours employed.
Paper ‘is .marbled in a similar. manner to the edges
of books, but, instead of usinga round staff, combs
are employed, the ‘teeth of which are more or less
apart, to form the volutes or any other figure. It
requires skill to place the sheet of paper fiat upon
the surface of the gummed water, and to withdraw
it without deran'ging .the colours. To do this, the
marbler takes the sheet between the thumb and fore-
finger of one hand in the middle of one of its ends,
and with the other hand, and between the thumb and
fore-finger also, the middle of the other end of the
sheet. He then lays the sheet upon the gummed
water, and removes it without suffering it to slide
upon .the coloured surface. He then hangs the sheet
to dry upon the bar of a frame with the coloured
side outwards. Fresh colours are added to the
gummed vsurface after every dipping.
This account does not agree in many particulars
with the process, as we have just seen it practised
by one of the most skilful marblers in London.
The patterns are. arranged into five classes, in each
of which there are numerous varieties. The first,
known as small brown, consists of small round spots
or shells : the second is the Spams/z pattern, consist-
ing of a shaded ground with marble veining upon it.
Patterns in these two classes are formed by simply
dropping the proper colours upon the surface of the
gum solution in the right order, when they arrange
themselves into the required pattern. In the l/zz'rol
class are eurlecl patterns; the colours having been
thrown on, the spiral or curl is produced by a stick:
in the fourth class are Datolz patterns, in which first
the stick and then the comb produce the peculiar
effects. The fifl/z class includes Gloucester patterns,
in which a wavy appearance is produced below the
spots. _
- The trough is made of wood about 3 feet long by
2 wide, and 8 inches deep, and is placed before the
window. The colours are in jars 20 or 30 innumber,
on ~the right hand side of the operator, each jar con-
taining its own-brush, which is a loose bristle-tool.
Now suppose a black and white marble pattern to be
required: the marbler first cleans the surface of the
trough by passing a straight-edge along it, and turning 1
‘taken up by the paper as before. We also saw a
at the side. Then taking the brush out of the black f
theiimpurities over the end into a small waste trough
colour jar, and shaking it in the jar to get rid of
superfluous colour, he holds the brush at an angle
about a foot and a half or two feet over the surface of
gum: solution, and jerks down upon it a succession of
drops,1moving his hand along so as to distribute them
evenly: ‘the drops remain in the place in which they
fall, I and expand into‘ disks. Returning the black
brush’. to its jar, hev next takes the white brush and
lets fall ai‘few showers of white drops. The white
colour,- instead. of forming drops as the black did,

threads its way with greatrapidity among the spaces
left between the black drops, producing the peculiar
spotted and veined appearance of black and white.
marble. Then taking a sheet of paper, the operator
places it flat down upon the surface, tapping it gently
here and there to secure perfect adhesion; he next
places a stick, about four feet long, across the longer
dimension of the trough, and taking up the paper by
its two further corners, turns one half of. the sheet
over the stick: then lifts the stick off with the paper
hanging upon it marbled in themost perfect man-
ner. In fact, wherever the prepared liquid surface
is touched by the paper, the whole of the pattern
is completely transferred from the liquid to the
paper. The stick is then placed across a space be-
tween two horizontal bars and left to dry The
trough is dressed as before, for the marbling of a
second sheet in a similar manner.
Now in this operation it is evident that the black
colour is ground up with a liquid vehicle or menstruum.
different from that used for the white, so that the
two colours may mingle without mixing or blending
together. If one colour be mixed up with water or
gall or thin gum solution, the other colour must be
mixed with an oil of some kind. This will explain
how it is that the colours are kept separate when only
2 are employed, but it is difficult to understand the
operation when 5 or 6 distinct colours are used, each
bearing its share in the general effect, just as the
differently coloured threads do in a woven pattern.
The marbler produced before us, with 5 or 6 colours
and some curious manipulation, a pattern which he
named the Battle zy“ Waterloo, from some fanciful
resemblance in the pattern to the colours of the
uniforms of the opposing forces at the battle. After
6 successive showers of different colours, the marbler
took a stick, pass-ed it down apparently to the bottom
of the trough, and then moved it rather quickly back—
wards and forwards in lines parallel to the shorter
sides ‘of the trough; the effect of this was to produce
a streamy, wavy appearance. He next took a comb
of the width of the trough, with brass teeth about a- th
inch apart, and dipping it into the trough at the left-
hand extremity, moved it through the pattern, sup-
porting the two ends of the comb on the two long
ridges of the trough. All the colours streamed
_ through the teeth of the comb, and the pattern formed
‘ by the previous operation was immediately changed
into that small curious shelled effect, which is more
easily conceived than described. This pattern was
dozen books marbled at the edges: no clamp was
‘used except the pressure of the operator’s fingers,
' and the concave of the upright edges was not dis—
turbed. Albook was sent to show the pattern, which
1 was. reproduced in less than a minute, one dressing
being suficient, as the edges were successively dipped.
into different parts of the trough.
. The effects produced by this art are of a very pleas:
ing and surprising kind. The complexity of many
of the patterns is only apparent, for the patterns
themselves are produced by the simple means which
MARL—MARQUETRYé-MASONRY.
235
we have attempted to describe. We must apologise
for not giving more precise details respecting the
mixing of the colours: they were purposely withheld
from us, but there is no doubt that any one inter-
ested. in taking up and extending and improving this
remarkable art, would with a little chemical know-
ledge become a skilful marbler.
We may add that the English marbler professes to
use the following pigments, &c. for his colours :—
For llae, indigo, ground up with white lead or Prussian
blue and verditer, may be used; for green, indigo and
orpiment, the one ground and the other tempered,
mixed and boiled together with water; or verdigris, a
mixture of Dutch pink, and Prussian blue or verditer,
in different proportions : for yellow, orpiment, bruised
and tempered; or Dutch pink and yellow ochre : for
real, the finest lake, ground with raspings of Brazil-
wood, prepared by boiling for half a day 5 or carmine,
rose-pink, Vermilion, and red-lead; the two latter
should be mixed with rose-pink or lake, to bring them
to a softer cast: for orange, orange-lake, or a mixture
of Vermilion or red-lead with Dutch pink I: for purple,
rose-pink and Prussian blue. Into all these colours,
properly ground with spirit of wine, a little ox or fish
gall is added; the gall to be 2 or 3 days old: and if
the colours do not dilate sufficiently, more gall is
added; but if they spread too much, more colour,
without the gall, is added. .
The beautiful polish of marble paper is imparted by
first rubbing the paper, when dry, with a little soap,
and then polishing with a marble stone, an ivory knob
or glass polisher, or with a jasper or agate burnisner.
MARGARIC ACID. The fatty acids are noticed
in the article CANDLE, vol. i. p. 287.
MARINE ACID. See Hrnnocnnonrc Acm—
SA-LT.
MARINE SALT. See SALT.
MARINER’S COMPASS. See COMPASS—MAG-
NETISM.
MARE is a mixture, compact or pulverulent, of
carbonate of lime, clay, and siliceous sand, and,
according as one or other predominates, a marl is
said to be calcareous, clayey, or samh/
MARQUETRY. The nature and method of this
beautiful description of inlaying are noticed under
BUHL-WORK. In the marquetry or marqueterie-inlay,
woorls are arranged in a great variety of tints in the form
of birds, flowers, ornaments, &c.: inbuhl-work, metals
are inlaid upon grounds of tortoiseshell or ebony, or
vice versc'l. The earlier specimens of marquetry were
executed in woods of the natural hues, but in later
times stained woods were employed; these have the
disadvantage of fading by age; but in the admirable
specimens sent to the Great Exhibition by M. Cremer
of Paris, the woods are stained by the process of M.
Boucherie, which is said to give them a permanent
dye to a considerable depth. The effect of shading
is produced by immersing the‘ pieces in hot sand.
The various parts being cut out of the required tints
of the proper form, are placed according to the
design and fixed on paper; they are then applied like
veneer to the piece of furniture, after which they are

cleaned off, slightly polished, and the finer lines en-
graved. In the manufacture of pargaelerz‘e for floors,
the same principle is carried out as in marqueterie,
only on a holder scale. Woods of different colours
are cut to pattern, and inlaid or so arranged as to
produce very beautiful effects for floors.
MASONRY,1 is the art of shaping and uniting
stones for the various purposes of build-ing. It in-
cludes the hewing of stones into the various forms
required, andv the union of them by level, perpen-
dicular, or other joints 3 or by the aid of cement, or
of iron, lead, 850. The operations of masonry require
much practical dexterity, together with a certain
amount of knowledge in geometry and mechanics.
For the scientific operations of stone~cutting, we
must refer to special treatises,2 our object in the
present article being to notice a few of the practical
details of masonry.
Probably the earliest masonry is that of the Egyp-
lz'arzs, which is chiefly remarkable for the enormous
size of the stones. employed; they are said to he often
as much as 30 feet in length: they were used without
mortar, for having been once placed, they were not
likely to be disturbed. The Cyclopaeaa masonry
alluded to by Homer, some remains of which exist in
the walls at Mycenae and Tiryns, are formed of large
and irregularly-shaped masses of stone, with the inter-
stices filled with smaller pieces. Tyrr/zem'aa, or Elms-
caa masonry, is also of large and irregularly-shaped
masses of stone, but they are fitted together with
such exactness as not to admit of smaller stones in
the interstices: the more ancient remains of Greece
and Italy afford specimens of this kind of masonry.
The next improvement seems to have consisted in
I ‘w . , ’
5 ~ ._
w“?— “we-Magma a -
‘gééligfiiiiyétefmfi. ’
"I. "V i ‘at ' v‘gglhy
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1 , no,
11111 1 . F, ___,,__v__~_q_ a, , . ’
~111111111111111n1111111mnm1111111’ 7/ n; ,1,-
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"1 ‘l111111'11"1"11111 ' “ ‘5-7141 11.’
1t?! llliillllllhr. __
Fig.- 1398.
INCE RTUM.
working the stones so as to make the joints or beds '
horizontal or nearly so, and the vertical joints were
made flat, but not perpendicular to the horizon-
tal ones: specimens of this kind of masonry are found
at Fiesole, Populonia, and elsewhere. All these

(I) The derivation of the word mason has led to some dispute.
Some derive it from the Latin macerz'a, along wall; others from
machinw, because the builders used machines in building the
walls. It appears to be the same word as 'maz‘son, a house or
mansion.
(2) See Peter Nicholson’s “ Popular and Practical Treatise on
Masonry and Stone Cutting,” published in 1827. Gwilt’s En-
cyclopaedia of Architecture, 1842, or the article Masonry in Rees’s
Cyclopadia. Also Dobson’s Practical Treatise on Stone Cutting,
publishedin Weale’s Rudimentary Series.
236 ‘ MASONRY.
kinds of walling were put together without mortar. of the-great temple at Baalbec, even the second course
For the ordinary purposes of walling, the Greeks and is formed of stones from 29 to 37 feet long, and about
Romans used several methods, such as the opus 9 feet thick: under this at the north-west angle and
incertum, now called random, or rattle walling and about‘ 20 feet from the ground are 3 stones, which
made'with stones of irregular shapes and sizes : the measure 182 feet 9 inches in length, by about 12 feet



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a i
if? i in‘ 7 a‘
‘HR! (‘fill H ’
ance, formed with square stones laid diagonally; in length. The Roman emplectum found in England
‘Us i,‘ -- M , . "
snail ~._. 1 in -
@115 ,_._~ 1 3 . u Fig. 1399. RETICULATED. Fig. 1402. GREEK EMPLECTUM.
opus reticulatum, so called from its netlike appear- thick; two are 60 feet, and the third 62 feet 9 inches
2'sodomzmz and pseudz'soclomum, ascribed by Vitruvius and France has in some cases courses of tiles built in
to the Greeks: they were formed in regular courses, at intervals, as shown in Fig. 14104:, the large surfaces






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' “mill




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illiliillililliudi




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Fiy- 1400- ISQDOMUM' - .Fig. 1403. ROMAN EMPLECTUM.
which in the isodomum were allof equal height, but
unequal in the pseudisodomum. Jihzpleczfzmz resembled
the last two in external appearance, but the middle
of the wall was of rubble, the facing only being in
of the flat tiles making a good bond. The courses
are usually about 4: inches deep, the stones in most
instances of rather cubical proportions, and the joints
commonly wide and coarse. Informing foundations,
it was common among



















' ‘3%, the Romans to dig a a‘ _. g 1,. f I trench, not very deep, '_
m I: and scarcely wider than . -
,yHL-fi it the wall to be raised from {lily/gym“ A
. s M ' 5,. it; the bottom of the l
_ {l'llmm' {' ' i’ ‘a I‘, trench was then covered may/a . 1 will \ with gravel or dry hard 4 a’mm I
rubbish; upon thls solid H p at
I H masonry, usually of the L
same width as the up-
per part of the wall, mum , I
' ' ' " was built up to the level , - ~==i ' l'-‘-"\' _ i Fig.1401. I’SEUDISODOMUM. of the Surface of the . ,mwéw _¢“€frn_
regular courses. In all these kinds of masonry the ground. '
Stones were Small, and were laid in mortar; but in ' After the Romans had
the erection of buildings, where large blocks of stone 'quitted Britain, the masonry probably consisted of
were employed, the Romans used no cement. 110- the coarsest rag or rubble work, In a few of the
cording to Pocock, on the west side of the basement *early buildings, considered by some to be Saxon,
Fig. 1404. MASONRY AND TILES.

MASONRY.
- 237’
the quoins, the jambs of doors and windows, ‘and’
occasionally some other parts which are built of
hewn stone, are formed of blocks alternately laid
flat and set up on their ends: the upright stones


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Fig. 1406. FINE AND WIDE JOINTS.


Fig. 1405. WIDE JOINTS.
are usually of considerable length in proportion
to the others; hence the term long and .s/zort won/c
applied to this construction. In the early Norman
style walls were built on the inside face with rubble
plastered, and the outside was also often the same: in
large buildings this was frequently of ashlar, with
wide coarse joints, and the mortar made with coarse
unsifted sand or gravel. In the early part of the
twelfth century, the character of the masonry im-
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\ Timid-fr)?” 1*
Fig. 1407.
LONG
Fig. 1408.
‘AND SHORT WORK.
proved; the mortar was finer, the stones were set
with close fine joints, ashlar was more generally used
for the external, and in some cases for the internal
facing. Throughout the Norman style the stones of
the plain ashlar work generally approached to cubes
in shape, and the courses varied from about 6 to 9 or
10 inches in height; in rubble walls, herringbone
nor/c was frequently used. In late Norman works,
a,
a v// ‘ q z‘ \ . 3 (1': a‘ I‘ a" ‘Hinds ' .
\ 11:"; a?" 2


- -‘. l I ‘ \
- re
~\'
._‘ y’
the stones used in the facing of walls were cut into
various shapes for the sake of ornament, the simplest
being the opus reticulatum or diamond work, in
which the stones were reduced to squares, and laid
angularly. In middle age masonry the stones were
seldom larger than could be lifted by two or three
men, and they were often small enoughto be lifted _

by one man. ' “ After the expiration of the‘Norm'an
style, masonry had no characteristics sufficiently~
decided to mark its date, except where fiints were used;
in rubble work these were employed in every age in
districts in which they abound, but they do not
appear to have been laid with any care, previously to
the introduction of the Early English style. At this
period they began to be split or broken to a mode—
rately flat surface on one side, which was placed
outwards, and formed a tolerably even face to the
wall; but in most buildings of this date, a portion
only of the flints have been thus broken, and the
surface of the wall has been covered with plaster.
In the Decorated and Perpendicular styles, especially
the latter, flints were dressed with much greater
care, and not unfrequently reduced to rectangular
forms, so as to be laid in even courses with as much
regularity as bricks. It was by no means uncommon
for flint and stone work to be used together in walls
for the sake of ornament: the most usual arrange-
ment was in alternate squares, but sometimes the
stone was out into the shape of panelling, with
tracery and cusps, and the interstices were filled with
flints.” 1
Various kinds of masonry are still practised, but
they all admit of being classed under three heads :—







O\l
- ,5 "a
Fig. 1412.
Fig. 1410.
Fig. 1411.
1st. Rnoole work, Fig. 14110, in which the stones are
used without being squared. 2d. Oonrsed worn, Fig.
14111, in which the stones are squared more‘ or less,
sorted into sizes, and ranged in courses. 3d. As/zinr
work, Fig. 1e12, in which each stone is squared and
dressed to given dimen- .- -
sions. In London the
term ashlar is commonly
applied to a thin facing of
stone placed in front of
brickwork. [See AsHLAnfj
The rubble wall, Fig. 1413, is improved in appearance
and solidity by the introduction of out stone as in the


~45!
til




Fig. 1414.
coping c, the plinth p, the quoin c’ p’, and the piers c p.
The wall, Fig. 14:14, is cased on both sides with cut

(1) “ A Glossary of Terms used in Grecian, Roman, Italian and
Gothic Architecture." Fifth Edition, Oxford, 1850. These very
beautiful and valuable volumes contain pictorial examples of the
specimens of work and style as they actually exist. .
' 238
MASONRY.
stone, the middle being filled with rubble. In such
' case beading or 60ml stones [1 12, are carried entirely
through the thickness of the wall at certain intervals,
to prevent the sides being forced apart by the set-
tlement of the rubble between them. These few
explanations will enable the reader the better to
appreciate the following directions, which are abridged
from the article MASONRY in Rees’s Gyclopmdia.
In the modern practice of stone walling the bedding
- joints should always be horizontal, when the top of
‘the wall is to be'terminated horizontally. In bridge
building and in the masonry of fence walls upon in-
.clined surfaces, the bedding jointsimay follow the gene-
ral direction of the work. The footing of stone walls
should be constructed with stones as large as can be
‘conveniently procured, squared and of equal thickness
in the same course, with the broadest bed downwards.
The vertical joints of an upper course must break
joint, that is, must not fall on those below. If the
walls of the superstructure be thin, the stones com-
posing the foundations may be disposed so that their
length may reach across each course from one side of
the wall to the other. Where the walls are thick and
stones cannot be procured long enough to reach
across the foundations, every second stone 'in the
course may be a whole stone in breadth, and each
interval may consist of two stones of equal breadth,
that is, placing fieacler and stretcher1 alternately. ' If
those stones cannot be procured, a header and
stretcher must be laid alternately from one side of
the wall, and from the other side another series of
stones in the same manner, so that the length of each
header may be two-thirds, and the breadth of each
stretcher one-third of the breadth of the wall, and so
that the back of each header may come in contact
with the back of an opposite stretcher, and the side
of that header may come in contact with the side of
the header adjoining the said stretcher. In founda—
tions of some breadth, for which stones cannot be
procured of a length equal to two-thirds the breadth
of the foundation, the work should be built so that
the upright joints of any course may fall on the middle
of the length of the stones in the course below, and
so that the back of each stone in any course may fall
on the solid of a stone or stones in the lower course.
The foundation should consist of several courses, each
decreasing in breadth as they rise by sets off on each
side of 3 or 4 inches in ordinary cases. The number
of courses is regulated by the weight of the wall, and
by the size of the stones composing these foundations
or footings.
Fig. 1415 represents that form of masonry called
by the Greeks clz'alorzous, in which the stones were of
the same form and dimensions, but placed in courses
of unequal height. Such stones had their length equal
to double their width.
There is a variety of masonry met with in Italy in
which, instead of presenting in the same course one
header and one stretcher alternating, there is a course

(1) These terms are explained in the article BRICKLAYING, to
which we must also refer for directions respecting the preparation
of foundations.

'of headers and a course of stretchers, like the old
English bond in brickwork: as the headers pass



Fig. 1415. DIATONOUS-
entirely through the wall, the work is very solid.
See Fig. 14:16. I
A. wall built with unhewn stone is called a rubble-
wall, whether mortar be used or not. This species of


Fig. 1416. ITALIAN.
work may be coursed or uncoursed. In the former the
stones are gaged and dressed by the hammer, and
thrown into different heaps, each heap containing
stones of the same thickness. The masonry is then
laid in horizontal courses, but not always of the same
thickness. The uncoursed rubble wall is formed by
laying the stones in the wall as they come to hand,
without gaging or sorting, only the sharp angles are
first knocked off with the thick end of the scabbling
hammer.
Walls are most commonly built with an ashlar
facing, and backed with brick or rubble work. In
London, where stone is expensive,‘ the backing is
generally of brickwork; but such is not the casein
the north and in places where stone is abundant.
Walls faced with ashlar and backed with brick or un-
coursed rubble, are liable to become convex on the
outside from the greater number of joints, and con~
sequently from the larger quantity of mortar placed
in each joint, as the shrinking of the mortar is in
proportion to the quantity: such a wall is therefore
inferior to one wherein the facing and backing are of
the same kind, and built with equal care, even sup-
posing both sides to be of uncoursed rubble, which is
the worst description of walling. Where a wall con-
sists of an ashlar facing outside, and the inside of
coursed rubble, the courses at the back should be as
high as possible, and the beds should contain very
little mortar. Course rubble and brick backings
admit of the introduction of bond timber; but wooden
bonds should not be continued in length; and unless
used sparingly they weaken the masonry, making the
wall liable to bend. It is better to introduce only
‘such small pieces, with the fibres of the wood perpen-
MASONRY.
239
dicular to the face of the wall, as are required ‘for the
fastenings of battens and dressings.
In ashlar facing the stones usually rise from 28 to
30 inches in length, 12 inches in height, and 8 or 9
inches in thickness. Although the upper and lower
beds of an ashlar, as well as the vertical joints, should
be at right angles to the face of the stone, and the
face, bed and vertical joints at right angles to the
beds in an ashlar facing; yet when the stones run
nearly of the same thickness, it is of some advantage,
in respect of bond, that the back of the stone be in-
clined to the face, and that all the backs, thus inclined,
should run in the same direction; since a small degree
of lap is thus obtained in the setting of the next
course: whereas if the backs are parallel to the front,
no lap can take place when the stones run of an equal
depth in the thickness of the wall. It is also of ad-
vantage to select the stones, so that a thicker one and
a thinner one follow each other alternately. The dis-
position of the stones in the next superior course
should follow the same order as in the inferior course,
and every vertical joint should fall as nearly as possible
in the middle of the stone below.
In every course of ashlar facing, in which the back-
ing is brick or rubble, local or llroag/zslones should be
introduced, their number being proportioned to the
length of the course; and every one of these stones,
if a superior course, should fall in the middle between
every two like stones in the course below. In some
cases masons introduce bond stones of greater length
than the wall will allow, in order to show that they
have done their work properly; but as the pro-
jecting ends have to be knocked or cut off, the wall
is thus liable to be shaken, or the bond_stone itself
split.
In piers where the jambs are coursed with ashlar
in front, every alternate jamb stone should go through
the wall with its beds perfectly level. If the jamb
stones are of one entire height, as is often the case
when architraves are wrought upon them and also
upon the lintel crowning them, every alternate stone
of the stones at the ends of the courses of the pier
which are to adjoin the architrave jamb, should be
a bond stone; and if the piers be very narrow be-
tween the apertures,_no other bond stones will be
necessary in such short courses. With wide piers the
number of bond stones must be proportioned to the
space. Bond stones must also be carefully attended
to in long courses above and below windows. Their
sides must be parallel and perpendicular to each
other, and their horizontal dimension in the face of
the work not less than the vertical one. The vertical
joints, after receding about gths of an inch from the
face of the work with a close joint, should widen gra-
dually to the back so as to form hollow wedge-like
figures for the reception of mortar and packing. The
adjoining stones should have their beds and vertical
joints filled with oil-putty from the face to about
gths of an inch inwards, and the running part of the
beds with good mortar. Putty cement is very durable,
and although the oil, spreading over the surface of the
contiguous stones, produces a disagreeable effect, yet

this disappears in a year or two, and the work appears
as if of one piece.
All the stones of an ashlar facing should be laid on
their natural beds: unless this be attended to, the
stones are apt to flush at the joints, and this promotes
decay from the action of the atmosphere. Where
walls, or insulated pillars of small dimensions, are to
be carried up, every stone should be carefully bedded
level, and not be concave in the middle; for if such
be the case, the weight borne by the pier or pillar will
probably cause the joints to flush. The unsightly
cracks seen in masonry, as at l b’, Fig. 1412, are
produced in consequence of the stones not lying flat
in their. beds. It is better, if possible, to make
every course in the masonry of a pier or pillar, in
one stone. Large columns in a single block have
a striking effect; but where a single block of suffi-
cient size cannot be obtained, the next best arrange-
ment is to have as few courses as possible, and the
stones ought to be so selected and arranged as to
conceal the joints as much as possible; choosing them
of the same colour, and arranging the grain in one
direction. [See Sronu] Vertical joints in columns
ought not to be allowed.
In order to prevent the stones from slipping upon
each other, and the joints from separating, it is neces-
sary in some cases to insert between them a cramp or
clowel, that is, a piece of iron, copper, or wood of a
dove-tail form,‘ as shown in Fig.14117. These are
inserted half in each stone,
_ %
fixes it firmly to the stone. Dowels are sometimes made Fiy- 1417.
sometimes run with lead. The holes in the walls
of the Coliseum and other monuments at Rome
and the two having been
placed, lead is run into the 2 2
space round the dowel, which
of hard stone, and are then run with cement. The
ancients were accustomed to unite one stone with
another by means of iron or bronze cramps, Fig.14s18,

ll__\
ill
13::




Fig. 1418.
have been drilled or cut for the purpose of extract-
ing the bronze cramps that united the courses of
masonry together. Oak dove-tails were used in the
Parthenon at Athens for the same purpose. It is not
a good plan to secure dowels by means of lead: it
may be necessary with bad workmanship, but a good
workman will prefer to trust to very close and work-
manlike joints, carefully fitting dowels and fine mor-
tar. Iron cramps, used as fastenings on the tops of
2&0
'MASQNRY.
copings, &c., are very unsightly, and ought to be
avoided: they are even injurious if exposed to the’
corroding action of the atmosphere, for they not only
produce ugly stains, but will sooner or later burst
and split the work they are intended to protect.
Stones'are said to be jogglerl together when a pro—
jection is worked out on one stone to fit into a corre-
sponding hole or groove in the other, as in Fig. M19 ;
and when the two stones are united, only a vertical









‘.ljlji‘jl‘it'
. ‘ll ,sflili'i'ltrl \ ‘1
in ~\
t it
i l \
‘llhil ' ‘
joint will be seen. This plan occasions great labour
and waste of stone; hence eZozooZ-joggles are used:
these are hard pieces of stone cut to the required
size, and let into corresponding mortices in the two
stones to be joined together.
The tools employed by the mason are different in
different countries, according to the quality of the
stone. ~In London, where stone is scarce, it is cut
into scantlings by the saw, described under MARBLE,
Fig. 1382. In places where stone is abundant it is
divided into smaller scantlings by means of wedges.
Hard stone and marble are reduced to a surface by a
mallet and chisel. The mallet is similar to a bell in
shape, except a portion of the broadest part, which is
rather cylindrical: the handle is only just long enough
to allow it to be firmly grasped in the hand. The
chief implements in London for hewing stones are the
mallet and tools. The tools are of iron tipped with
steel, and the cutting edge is the vertical angle. The
end of the tool struck by the mallet is a small portion
of a spheric surface, and projects on all sides beyond
the adjoining part or hand-hold, which increases in
magnitude towards the middle of the tool, and thence
tapers forward, in the form of a wedge or pyramid, to
the entering or cutting edge. The other tools used


Y
I.
i
i


by the mason are a level, a plumb-rule, a square, a.
bevel, and straight and circular rules of various de-
scriptions for trying the surfaces as the work proceeds.
In working the face of a stone the tools used in
London are the point, the mall-tool, the boaster, and
the broad-tool. The operation of working with a
point is called pointing, and that with the boaster is
termed boasting. The operation of the point leaves
the surface in narrow furrows with rough ridges be-
tween them. The inch-tool is used in cutting away
the ridges, and the boaster in making the surface of
the work nearly smooth. The point is, in breadth,
at the entering part, from %th to gths of an inch, the
boaster 2 inches wide, and the broad tool 3%,,- inches
at the cutting edge. In the use of the tool the cutting
edge is always perpendicular to the same side of the
stone. There are two kinds of operations performed
with it? suppose the impression made by the whole
breadth of the tool at the cutting edge to be called a
cavity. In one operation, the successive cavities fol-
.lowone another in the same straight line untilthe
,. poz'rzfi.

breadth or length of the stone is exhausted: these
successive equidistant parallel lines are repeated in
the same manner until the whole surface of the stone
has been gone over by the tool. This method of
hewing is called stroking, which is a kind of fluted
surface. In the other operation every successive cavity
is repeated in new equidistant lines throughout the
length or breadth of the stone, then a new series of
cavities is again repeated throughout the length or
breadth of the stone, and thus, until the whole breadth
or length of the stone is exhausted. This method is
called tooling. Tools for working cylindrical and
conical parts of mouldings are of all sizes, from % inch
upwards; but those for working convex mouldings
are generally é— inch broad, unless in confined spaces,
where such breadth cannot be admitted. A stone is
taken for the most part out of winding with points,
and entirely with the inch tool.
In London the facings of buildings made with
squared stones are either stroked, tooled, or rubbed.
In places where the sawing of stone by the use of the
saw does not compensate for the loss of time taken
up in sawing, the operation is entirely performed by
the mallet and chisel.-
I/Vhen stones are very unshapely, a stone-care, jad-
cZz'rzy-aroe, scaoolz'rzg-lzammer, or mail is used previous
to the operation of hewing, in order to bring the
stone nearly to shape.‘ One end of the jedding-axe
is flat, and-is used for knocking off projecting angular
points, and the other end is pointed, for reducing the
different surfaces nearly to the intended form.
In some places the surfaces of the stones are formed
with zig-zag lines, called herring-bone, already alluded
to. In Scotland, in addition to hewn-work, there are
other kinds, known as droved, oroao/zecl, and striped.-
Droving is similar to random-tooling or boasting: the
chisel for broaching is called a pzmo/z, instead of a
Breached work is first droved, and then
broached. Striped work is also first droved. In Aber-
deen,- where the hardness of the granite does not
admit of these operations, a scabbling-hammer is
used, by which the stone is picked until the surface
is nearly of the intended form.- This operation is
termed rzz'dgz'rzg, and the work done, flatly/ed wow/r.-
Where the surface is smoothed by means of sand or
grit stone, it is called ruboerl war/1:.
In forming a plane surface the mason first knocks
off the superfluous stone along one edge of the block,
as a a, Fig. 14:20, until
it coincides with a
straight edge through-
out its whole length:
this is called a chisel
dump/it. Another chisel
draught is then made
along one of the adja-
cent edges, as to, and
the ends of the two are connected by another draught,
as a 0‘ fa fourth draught is then sunk across the last,
as 5 (Z, which gives another angle point (Z in the same
plane as ab and a, by which the draughts (la, and a a:
can be formed; and-the stone is then knocked off


Fig. 1420.
MASTIC—MATCHES.
‘241
between the outside draughts until a straight-edge
.coincides with its surface in every part.
Various curved rules,.or templates, and gages, are
employed in hewn work. For example, in forming
\ cylindrical or moulded sur-
faces, curved in one direction
only, the mason sinks two
parallel draughts at the oppo-
site end of the stone, until
they coincide with a mould or
template, cut to the required
shape; and he afterwards
works off the stone between
these draughts by a straight-edge applied at right
angles to them. See Fig. M21.
In measuring masons’ work, the cubic content of
the stone is taken, without deduction for subsequent
waste. If the scantlings be large, an extra price is
allowed for hoisting. The labour in working the
stone is charged by the superficial foot, according to
the kind of work, as plain work, snnlr work, moulded
war/e, &c. Pavings, ‘landings, 850., and all stone less
than 3-inch thick, are charged by the superficial foot.
Copings, curbs, window-sills, 860. are charged per
lineal foot. Cramps, dowels, mortice holes, &c. are
charged separately. A journeyman mason receives
from 4:8. to 58. 6d. per day, and the labourer from
28. (id. to 3.9. per day; but masons working at piece-
work will often earn much more. The remunera-
tion of a stone carver depends on his talent, which
often rises to that of an artist, and is appreciated
accordingly.
MASTIC, a resinous substance collected in the
form of tears, from the Pislnez'n lenlz'sens, a small
evergreen tree found in the south of Europe, the
north of Africa, and the Levant. It is especially
abundant in the island of Chios, where the mastic
forms one of the most important productions. In
order to collect it, numerous incisions are made in the
trunk and branches of the trees, in the middle of July,
and from these the sap gradually flows, and thickens
by exposure to the air, generally adhering to the tree
in the form of drops, but if very abundant, falling to
the ground before it hardens. The tears which form
on the bark are most esteemed, and are removed by
a sharp instrument, cloths being spread beneath the
tree to catch them as they fall. The first gathering
is completed in eight days, after which fresh incisions
are made, and the trees are left untouched, until the
25th of September. The second gathering then begins,
and is carried on at intervals until the 19th of No-
vember, when it ceases for the season.
The best mastic is translucent, of a pale yellow
colour, vitreous fracture, and agreeable odour and
taste. It is a valuable ingredient in several varnishes,
and is also used for stopping decayed teeth. The
inhabitants of the countries whencemastic is obtained,
consider it highly efficacious in promoting a healthy
state of the mouth, and constantly chew it for that
purpose. It is this use of the substance which sug-
gested its name, mastic being derived from maslz'em'e,
to masticate.
VOL. II.


Mastic forms a pale and brilliant varnish, when
dissolved either in spirits of wine or oil of turpentine,
the latter being most frequently used, on account of
its clieapness. The best-picked mastic is used for
this purpose; and if turpentine be employed, the
proportion of mastic is three pounds to the gallon of
turpentine. The mastic is dissolved by agitation,
without heat, and the varnish thus made is strained
and poured into a bottle, which is loosely corked, and
exposed to the sun and air for a few weeks. A deposit
takes place, from which the clear varnish is poured off
for use; but the longer it is kept the better. This
varnish is much used for paintings and other delicate
works. It flows better on the surface than most
other varnishes, but is liable to chill. This chilling
results from the presence of moisture in the varnish;
and to prevent it the following method is sometimes
employed z—A quart of river-sand is boiled with two
ounces of pearlash; the sand is then washed two or
three times with hot water, and strained each time.
The sand is then dried in an oven, and when of a
good heat, half a pint of it is poured hot into each
gallon of varnish, and shaken well for five minutes;
it is then allowed to settle, and carries down the
moisture of the gum and turpentine.
MATCH, an implement used in firing military
mines or in discharging pieces of ordnance. The
match may be slow or gnz'ele. The slozo~mnlelz consistsof
a piece of slightly-twisted hemp, which has been well
soaked in a strong solution of saltpetre. When lighted
at one end it burns very slowly, a piece 1 yard .in
length being scarcely consumed .in 8 hours. When
in use it is revived by blowing upon it by the lips,
when it will ignite gunpowder or the cotton wick of
a fusee. In the formation of a qnz'e/r-mnleli the mate
rials used are a mixture of saltpetre and meal'ed gun‘
powder with spirit of wine and distilled or rain-water.
The water and the saltpetre are boiled for an hour
with a cotton wick coiled up in the solution: the
spirit is then added, and the mixture left to simmer
for a quarter of an hour. Some of the powder is then
added, and the whole left for 241 hours. The cotton
is next wound upon a reel, and the rest of the powder
sifted over it. After drying for some days the match
is fit for use. '
MATCHES. The comparatively low temperature
at which sulphur ignites led to its being used at the
end of a strip of wood as a means for procuring flame.
The old tinder-box with its flint and steel, tinder and
matches, was a troublesome, but ingenious arrange-
ment. As it has now become a matter of history, a
short description may be interesting to some readers.
The tinder consisted of carbon in a filmy form, pro-
cured by burning a piece of rag in a short cylindrical
iron box, called the tinder-60$, the loose cover of
which being inserted, extinguished the flame of the
burning rag, and left the carbon. The steel was a
strip of hard iron, curved round at the top and bottom,
so as to form a handle : this was held in the left hand,
and in the right a flint wedge, the sharp edge of which
being struck against the steel, chipped off minute
fragments: the heat developed by the percussion was
r.
24rd
MATCHES.
sufficient to ignite and even fuse these metallic frag-
ments, which, falling down into the easily combustible
carbon, ignited it at every point of contact. The
operator then blowing upon the tinder to keep up the
combustion, applied the point of one of the matches
to the incandescent carbon, and, with some little con-
trivance, managed to ignite the sulphur, which, in its
turn, ignited the wood of the match. The cover was
then returned to the box, and the weight of the flint
and steel pressing it down, extinguished the sparks
in the carbon. The operation was not, however,
always successful: the tinder or the matches might
be damp; the flint blunt, and the steel worn; or, on
' a cold dark morning, the operator would not unfrc-
quently strike his or her knuckles instead of the steel;
a match, too, might he often long in kindling ; and it
was not pleasant to keep blowing into the tinder-box,
and on pausing a moment to take breath, to inhale
sulphurous acid gas, and a peculiar odour which the
tinder'box always exhaled.
When, about the year 167 3, phosphorus was dis-
covered, and its easy ignition by mere friction made
known, all persons who could afford to procure the
costly novelty did not fail to do so. A minute portion
of it rubbed for a moment between the folds of brown
paper took fire, and ignited a sulphur match applied
to the flame. In 1680, Godfrey Hanckwitz, at his
laboratory in Southampton- street, Strand, manufac-
tured and sold large quantities of phosphorus for this
purpose; and so great was the fame of the new
method, that Godfrey set out on his travels to exhibit
and sell the article. The costliness of phosphorus
probably prevented its general introduction; and it is
remarkable that a century and a half should have
elapsed before this substance should have come into
general use for our best and readiest form of match.
It cannot, however, be said that during this long
period phosphorus was altogether neglected as a
means for procuring a light. P/zosplzorie lupers
were for some time in use: they were small wax
tapers, the wicks of which were coated with phos-
phorus: they were enclosed in glass tubes herme-
tically sealed, and when a light was required, one
end of the tube was cut off witha file, and the
taper took fire on exposure to the air. This plan,
however, was found to be inferior to friction with
brown paper, and in some cases it was dangerous, so
that it soon became forgotten. The next plan was
' to put a piece of phosphorus into a small phial, and
then to stir it about with a hot iron wire : the phos-
phorus was partially burnt in a confined portion of
air, and the interior of the bottle covered with oxide
of phosphorus. On removing the wire,'the phial was
corked tightlyfor use. ‘When a light was wanted, a
common: sulphur match was dipped into ‘the bottle,
and a small portion of the phosphorus adhering to the
tip, flame was produced‘ by ‘the ‘energetic ‘chemical
action of the sulphur andthe phosphorus. This plan
was for a long time a favourite one, and the writer re-
members these bottles being hawked about theestreets‘
of London: Another method was to rub the match,
after dipping it into the bottle, against a piece- of

corkrror soft wood, the friction more certainly pro-
moting ~the combination of the sulphur and phos-
phorus, and the consequent production of flame.
Another method of ‘kindling a match was by means
of Homlerg’s joyrop/zorus, or fire-bearer: it was a black
powder, produced by the calcination of flour, sugar,
and alum, which took fire on exposure to the air. A
small bottle of this powder, if well prepared, lasted a
good while, and was a convenient method of getting
a light, but one not likely to get into general use.
It was chiefly in the hands of the curious. Its action
was unknown until the discovery of potassium, when
it was evident that this metal, evolved from the potash
of the alum by the action of the charcoal of the flour '
and sugar, on being exposed to the air, absorbed oxy-
gen, and had its temperature raised sufficiently to
make the minutely-divided carbon incandescent.
The first z'usz‘uuz‘uueous lzylzl-mue/zz'ue was the “ in-
flammable air~lamp of Volta,” as it was called. This
consisted of a glass reservoir filled with hydrogen gas,
which could be subjected to the pressure of a column
of water on turning a stopcock. The pedestal upon
whichthe reservoir was placed was an electrophorus,
and the apparatus was so adjusted by connecting-
wires, that, on turning the cook, a small stream of
hydrogen rushed out, and met an electric spark from
the electrophorus, which ignited it, and the flame thus
produced lighted a match or taper placed directly
against it. This apparatus soon became a favourite
with scientific persons; but it was found that in con-
sequence of air getting into the hydrogen reservoir
it had a tendency to explode. It was therefore aban-
doned, and in after years the Dobereiner lamp, de-
scribed under HYDROGEN, took its place.
Many years ago, the question was much discussed
among chemists, whether the sudden compression of
a volume of atmospheric air, or oxygen, was sufficient
to produce a luminous effect in consequence of the
heat evolved. It was admitted that a flash of light
accompanied the sudden condensation of oxygen; but
this was referred by Thenard to the ignition of the
oil with which the apparatus was lubricated. Sup-
posing this to be the case, it occurred to some inge-
nious man to employ this flash of light in igniting a
piece of amadou or German tinder. This led to the
invention of “ the pneumatic tinder-box, or light-
syringe.” It consisted of a stout brass syringe, about
6 inches long and half an inch in diameter, closed at
one end, and fitted with an air-tight piston, at the
lower extremity of which was a cavity for containing
a piece of amadou. By suddenly driving the piston
into the tube, the air contained within it' was com-
pressed, its capacity for heat diminished, and conse
quently enough heat was liberated to ignite the tinder.‘
On quickly drawing out the piston, and blowing the
tinder into 1 a glow, a match could be ignited, and
sometimes acigar. On being first introduced, the
novelty and ingenuity of the contrivance excited
attention, and vast numbers of the fire-syringe were
,sold; but when it was found that several conditions
were necessary‘ for success, such as dry tinder, an
accurately-fitting piston, considerable strength of arm,
MATCHES.
ails
and a peculiar knack, the apparatus was declared to
be more troublesome than useful, and fell into disuse.
It may now be seen occasionally on the table of the
scientific lecturer, to whom it gives the means of per-
forming, a beautiful and instructive experiment.
Another scientific method of lighting a match was
by means of voltaic electricity. A plate of zinc, two
inches square, and a double plate of copper, dipped
into a small cistern of dilute acid, afforded a current
of sui‘ficient power to ignite a fine platinum wire con-
necting the copper and zinc plates. On touching this
wire with a piece of touch-paper, it instantly ignited,
and from this a match could be kindled; the direct
contact between the sulphur and the hot wire being
avoided on account of the tendency of sulphur and
platinum to combine at high temperatures.
But of all the ingenious attempts to get rid of the
old tinder-box, the oaymarz'ale male/ace, as they were
called, were the most successful. From them our
present lncg'fers are lineally descended, and they there-
fore deserve a respectful notice. The oxymuriate
matches were based upon the fact that when oxy-
muriate, or more properly chlorate, of potash is mixed
with sugar or other inflammable substance, it suddenly
bursts into flame on the contact of a drop of sulphuric
acid. Small portions of this mixture in powder were
first used for the purpose of getting a light; but it
was soon found that if mixed with gum, and made up
into a paste with a little vermilion for the sake of the
colour, strips of wood tipped with this composition,
ignited on being dipped into a bottle containing a
piece of asbestos soaked in strong oil of vitriol. The
bottle, and a number of matches with the tipped ends
downwards, were put into a neat little case of moire’e
mc'lallz'qac (a beautiful invention just introduced), and
this was called a pnosplcras-lozr. Although it con-
tained no phosphorus, it had lig/zl-dearz'ny or aya-
yz'vz'ng properties, whence we suppose the name, just
as our laczfers are light-bearing, only in this case we
get our derivation. from the Romans, while in the
former it is from the Greeks. On their first intro~
duction the phosphorus boxes were sold as high as
15.9 . each; they gradually fell to 10.9., 58., and 2s. 66l.
for a small box, at which last price they continued for
some years. '
There were, however, some inconveniences in the
use of these matches. When in perfect action the
sulphuric acid suddenly decomposed the chlorate paste
with a considerable rise in temperature, and the evo-
lution of oxygen, which entering into combination
with the inflammable elements of the sugar produced
flame. But in some cases, where the acid had become
weak by absorption of moisture from the air, the
match, instead of bursting into flame, merely smoul-
dered and spirted the acid about, sometimes to the
ruin of a lady’s dress. It might also happen that if
the match on being dipped did not act immediately,
it was economically returned to its case and another
selected : but the wetted match, thus returned,
coming in contact with another and more energetic
match, caused it to burst into flame, and thus the
whole collection of matches was ignited at once, and

shot out in all directions. To remedy this the maker,
instead of putting the tips of the matches downwards,
as heretofore, placed them upwards: but this did not
much mend the matter, for, on getting a light in the
dark, the match, on being taken out of the bottle, was
not unlikely to communicate acid or flame to its com-
panions. This defect was also remedied by placing
the matches in a horizontal position under a tin cover,
with printed directions to shut down the cover on
taking out a match, and to throw it away if it did not
ignite. The matches were improved by tipping them
first with sulphur, and then with the chlorate paste,
which made them ignite more readily. Camphor and
frankincense were sometimes mixed with the paste,
and the wood of the match was of cedar, so that a
pleasant odour was diffused in getting a light. But
there were defects still to be remedied. The cork of
the bottle became rotten from the efl’ects of the acid,
and the acid became weak by absorption of moisture.
A glass stopple was therefore substituted for a cork,
and in order more effectually to exclude the air a glass
cap was made to fit over the neck of the bottle. In
some cases the stopple was elongated, so that, instead
of having to dip the match into the bottle, all that
was necessary was to touch the tip of the match with
the tip of the stopple. A plug of India-rubber was
also used instead of a stopple or cork.
That there was still ample room for improvement
in this invention will be admitted from the fact, that
the box cost half—a-crown, and the matches a shilling
per hundred. This was not likely to be a very suc7
cessful rival to the old tinder-box. Many of our
readers will probably remember the notice posted and
advertised so abundantly —- “ Save your knuckles,
time, and trouble: use Heurtner’s EUPYRION, Price
One Shilling!” This invention consisted of 2 tin
cases soldered together, each about 1,-1- inch square,
but of different depths; one being 3 inches, and the
other about 1 inch deep, the longer compartment
holding the matches, and the shorter one the little
bottle of acid, so that, not being on the same level,
there was less chance of an accident. The cork was
covered with thin lead to prevent corrosion; the acid
was strong, and the match-composition good, so that
there was much to recommend this invention, and it
sold largely. _ _
But the Eupyrion shared the fate of all other use-
ful inventions which admit of being simplified and
economised. It was superseded by the laczfer-nzazfc/z,
which still reigns triumphant. The original lucifer-
match was tipped with a paste consisting of chlorate
of potash and sulphnret of antimony mixed up with
starch, and its great value consisted in igniting upon
being drawn across sand-paper. There were, however,
objections to these early matches: they required so
much pressure to produce the necessary friction, that
the top was often pulled off without igniting, and
when ignited, burst into a violent flame, and often
spirted out sparks of kindled matter which were
dangerous : moreover, the sulphurous antimonial
vapour was highly oflensive to persons with weak
lungs: the manufacturers were also liable to serious
12. 2
24:4:
MATCHES.
accidents from the contact of chlorate of potash and
sulphur.
The substitution of phosphorus for the sulphuret of
antimony was a great improvement introduced about
the year 1834. But before this, Mr. Jones, of “the
Lighthouse” in the Strand, invented the Promethean.
This consisted of a small coil of waxed paper, in one
end of which was a portion of sulphuric acid her-
metically sealed in a minute glass bulb, and surrounded
with the chlorate of potash-paste. When the end
thus prepared was crushed with a hammer, or by
means of a pair of nippers provided‘ for the purpose
the acid was‘ brought into contact with the composi-
tion, and a burst of flame was produced. For the
benefit of cigar smokers prometheans were made with
touch-paper, “which, instead of infiaming, burnt like a
slow-match.
The introduction of phosphorus into the lucifer-
match led to several decided improvements : saltpetre
was substituted, either wholly or partially, for chlorate
of potash, thus producing quiet ignition instead of
detonation: the ill odour was got rid of by omitting
much, if not all the sulphur, and using stearine
instead. Machinery was introduced for cutting the
wood into splints so as to ensure uniformity in the
size: other materials also came into use instead of
wood, such as ware-taper matches, fiesees of amadou or
brown paper, Veszwz'ans for lighting cigars, and some
other forms. '
Having recently inspected with some care the pro-
cesses concerned in the manufacture of lucifer-matches,
we now ‘propose to give a detailed notice of them.1
We offer no > excuse for the length of this article,
for the ‘subject 0f it, however apparently trivial, has
really become an important branch of industry. The
factory which we have visited produces upwards of
£200 millions of lucifer-matches every day; and we
learn from the Jury Report, Class XXIX, that, in
1849, Austria manufactured 50,000 cwts. of matches,
of which iii-fifths were consumed in the country and
1-fifth exported : that the materials consumed in one
year in Austria in this manufacture were, of nitre,
1,250 cwts., of phosphorus, 325 cwts., and of sulphur,
15,000 cwts. Other parts of Germany, France, Great
Britain, and the United States of America, also pro-
duce vast quantities of matches. In Austria the
export trade is greatly on the increase.
The wood employed in the manufacture of lucifers
is the best pine plank, as free from knots as it can be
procured. Each plank is cut across the fibres by
means of a circular saw, into 28 or 30 blocks, each
measuring 11 inches long, 41% wide, and 3 inches
thick. These blocks are cut up into splints by a
machine of simple but ingenious construction, which
we will endeavour to explain in a few words. To
the extremity of the horizontal arm of a crank is
attached a frame, which reciprocates to and fro with
the motion of the crank through a space of about 4:
inches. In this frame are fixed in a line some 30 or
4.0 lancets with the points projecting upwards, and

(1) Our thanks are due to Mr. Hynam of Princes-square, Fins-
bury, for permission to visit his factory.

separated from each other by pieces of brass. The
block of wood to be out is inserted by the small end
between uprights, and a lever placed upon it forces it
down to a position such, that as the lancet points
advance, the end of the wooden block is scored
or cut in the direction of or parallel with the fibres,
with as many lines as there are lancets. As the
lancets are withdrawn by the motion of the crank, a
scythe blade moving in a horizontal plane swings
round, and cuts off the end of the block to the depth
of the scores made by the lancets. The pieces thus
cut off will evidently be A-sided splints, square in
section, supposing, as is the case, that the lancets are
equidistant, and that the horizontal knife cuts exactly
to the depth of the lancet scores. When the hori-
zontal knife swings back, the block, from which one
layer of splints has thus been removed, descends
through a space equal to the depth of the section, the
lancet points again advance and recede, and the knife
again does its work. In this way the cutting is carried
on with such rapidity, that from 12 to 16 planks, each
12 feet long, 11 inches wide, and 3 inches thick, can
be cut up into splints in a day of 10 hours. Now,
supposing 141 planks are thus cut up, and that each
plank produces 30 blocks, we thus get 141>< 302420
blocks. Each block affords about 100 slices, which
are cut off by the horizontal knife, but as each slice
before being cut off has been scored by 31 lancet
points, we thus get ‘120 X 1 00 X 31=1,302,000 splints,
and as each splint makes two matches, we thus have
2,604,000 single match splints per day.
When a circular instead of a square section is
required, the wood is cut into splints by means of a
perforated metal plate, the perforations being so
shaped as to cause the block of wood when pressed
against its face, to be properly divided. Fig. 1422
shows the face of the plate, and Fig. 14123 a vertical
section of the same. The perforations are cylindrical













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000000000000 000000000000
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(000000000000) 000000000000
Fig.1422.
7 r7 E’ZZ?’EZ’%EZV zgzzgreggégey a
w * *.§~ §ss.s §sS£.§‘ =§§= a‘
swam ~ > i ‘= \ i # miswmmmuuswluts


Fig. 1423.
throughout, except at their openings on the face,
where they are slighly countersunk for the purpose
of presenting sharp-cutting edges to the wood, and
affording a more easy entrance. The perforations are
made as close together as possible, that all the wood
may be used, only suficient metal being left to afford
the necessary strength for cutting. The plate has a
steel face and a bell—metal back; it is 3 inches wide,
6 inches long, and about 1 inch thick. The back is
fixed against a firm resisting block or hearing, with
an aperture equal to the area of the perforations of
MATCHES.
245
the plate. The piece of wood being placed on end
in the direction of the fibres, the plate is forced down
upon it by means of a plunger or lever, when the
splints appear at the back of the plate, whence they
are removed before another block is applied. This
plan was patented by Mr. Partridge in 18112.
We now return to the square match. As the splints
fall off the end of the block by the action of the hori-
zontal knife, they pass down a shoot immediately
under the block into a room below, where they are
tied up into bundles, each containing half a gross.
For this purpose, a cradle or measure is formed con-
sisting of a section of a hollow cylinder of the capa-
city of half a gross of splints of the proper size, either
for the large splints or the second size called mz'nnz'ln'ns,
these being the only two sizes made at this factory.
The man begins by throwing a piece of string across
the cradle, then taking up a number of splints from
the confused heap, he ranges them in parallel order
by a dexterous system of tossing, knocking, and
jerking; having filled his measure, he catches the
two ends of the strings, ties up the bundle, throws
it aside, and then proceeds to make another, the
work being done with the rapidity and precision which
practice alone can give. These bundles are piled up
on the racks of a hot room or drying stove, and left
for some hours until moisture is expelled.
The next process is the sulfa/raring. The sulphur
is melted in an iron pot over a stove, and when sulfi-
ciently fluid, the two ends of the bundles are succes-
sively dipped, the bundle being shaken after each
dipping, in order to get rid of superfluous sulphur.
When the sulphur is dry, a second string is tied
round each bundle, so that when divided by the cir-
cular saw, each bundle of double matches may make
two bundles of single matches. Some of the matches,
however, are not divided until after having been
tipped with the phosphorus composition; but this is
merely a matter of convenience to the makers.
The matches are now ready for dipping in the
phosphorus composition. We were not informed as
to the precise ingredients of the composition, or the
method of mixing. Each manufacturer professes to
have his own recipe, which he regards as the best,
and therefore keeps secret. The ingredients are, how-
ever, well known to chemists: the principal one is
phosphorus, which is made into an emulsion with
glue or gum arabic, the former being preferable, since
gum absorbs moisture. Some makers use nitre, others
fine sand; and all use colouring matter, which may be
red ochre, red lead, smalt, or artificial ultramarine.
The following proportions have been found to
answer :—
Glue paste. Gum paste.
Phosphorus 2'5 .... .. 2'5
Glue..................... 2 Gum 2'5
\Vater 4'5 .... .. 3
Fine sand 2 .... .. 2
Red ochre 0'5 .... .. 0'5
Vermilion .......... .. 0'1 .... .. 0'1
Instead of the last two colouring substances 0'05
of Prussian blue may be used.
When glue is used it is of very inferior quality:

it is broken into fragments and soaked for a. few
hours in cold water; then dissolved in a large glue
pot, or copper c, Fig. 14%, heated by a water bath
W. When it is perfectly fluid and at the temperature
of 212°, the copper is withdrawn and placed in the
circular opening of the frame, Fig. 141425. The phos-
phorus is then added by degrees : it melts immediately
fi
\


Fig. 1424.
and subsides, but is kept in agitation by means of the
wooden stirrer s, which is furnished at the lower part
with projecting pegs, the object being as the glue
cools to obtain an emulsion of phosphorus in a
minutely divided state. The sand and colouring
matters are added during the stirring.
kept at the temperature of about 98°, suflicient to
retain it in a fluid state by placing the vessel 0 in a
water bath.
When the paste is made with gum it remains fluid
at ordinary temperatures, which is an advantage, but
it is seldom used on account of its hygrometric pro-
perties. In preparing the gum paste the weighed or
measured solution of gum is put into the copper c,
and heated to 212° as before; then removed to the
frame, Fig. 11.1.25, where the phosphorus is added and
beaten up into an emulsion until cold. The other
substances are added last.
Dr. Bottger gives the following recipe for a paste
common in Germany : —I’hosphorus 4L parts, nitre
10, fine glue 6, red ochre or red lead 5, smalt 2.
The glue to be converted into a smooth jelly with a
little water; the phosphorus to be rubbed down with
it at a temperature of from 14.0° to 150° ; after which‘
the nitre is to be added, then the red powder and
lastly the smalt, the whole to be carefully mixed into
a uniform paste.
The matches are prepared for dipping by a number
of children, who proceed in the following manner :—~
untying one of the bundles of sulphured matches,
the child standing before a very narrow frame, com-
posed of two uprights and a bottom cross piece, places
upon the latter and between the uprights, a narrow
board containing 50 grooves across it about half an
inch apart. ‘Taking a handful of matches the child
quickly deposits 3. match in each groove, the board
being so narrow that the ends of the matches project
considerably on each side 2 she then places a piece of
stout list along the board upon the middle of the
matches; upon this another grooved-board, which in
like manner is filled with 50 matches; then another
The paste is
2&6
MATCHES.
strip of list; and in this way the boards are piled up
to the top of the frame, and when 241 rows are filled,
a top cross—piece is put on and secured by thumb
screws, or by tying with string. The frame is then
taken in both hands: the ends of the matches are
knocked against the table evenly into one plane, and
it is then ready for the dipper. '
The match composition is spread out with a spatula
in a thin layer upon a stone slab which is heated by
steam below to keep the glue sufficiently fluid, and a
man standing besides it takes a‘frame in both hands,
and presses the sulphured ends of the matches down
upon the slab ; then turns them up to see that they
are properly dipped, and if necessary dips them a
second time. He then places the frame upright upon
one of its sides upon a table hear,- from which it is
taken by a boy into a room heated by a stove and a
hot fine. When sufficiently dry the frames are
removed to the filling room, where a number of little
girls stand at a table, which occupies the sides of the
room, with the frames of matches inclining against
the wall. The top cross-piece and the list being
removed, the child sweeps off the row of 50 matches,
catches up a box, slips it partly out of its 4~sided
case, dashes in the matches, closes the box and
deposits it in its place among a pile of boxes already
filled. She‘ then takes off the empty board and the
piece of list below it, and fills another box, this series
of operations being performed so rapidly that the
writer could not count 10 deliberately, in the interval
between the filling of 2 boxes. In a day of 10 hours,
a quick hand can dispose of 150 frames, or 3,600
boxes. It occasionally happens that in sweeping off
a row of matches, a match ignites and kindles the
others in the row ;' the girl has a box of sawdust at
hand in which to plunge and‘ extinguish the flames.
Fusees for lighting cigars are also made at this
establishment. The strips of pulp, ale. thin card-
board prepared by steeping in nitre, are sent from the
cutting room to a room where 41 girls are engaged in
the following operations: the maker’s name is first
stamped on each strip ; a girl then takes 25 strips in
her hand, and with a stick shaped like a paper-knife
takes up a portion of the red composition and spreads
in'over the cut extremities of the top strip; places
this on the table, and in like manner covers the ends
of the second strip, and so on till the 25 are prepared.
In the mean time another girl takes these strips, and
twists them so as to separate the fusees from each
other, and arranges them on a tray, which when full
is placed on a rack to dry. After this the strips are
made up in packets of 1,000 each.
In the drying of the lucifers and fusees, a portion
of the phosphorus is converted into phosphorous acid,
and escapes into the room; as the glue hardens and
solidifies, itv forms a protective coating to the re-
mainder of the phosphorus, and prevents it' from
oxidizing by exposure to the air. If we chip ofi a
piece of the composition from ‘a fusee by pressing the
thumb nail against it, the slight friction and the
sudden access of oxygen cause it to burst into flame;
so also by rubbing the end of a lucifer'match against

a hard substance, the protective glue coating is worn
off, and the heat excited by the friction kindles the
composition, which fires the sulphur and this the
wood of the match.
The acid fumes which are given off by the phos-
phorus during the mixing, the dipping, and the
drying, render the work-people liable to a very pain-
ful disease, which in Germany has led to such
shocking results, as to call for inquiry on the part of
the Government. The disease is in the jaws; it
commences with pain and swelling, and is followed
in many cases by exfoliation of the bone. The cause
seems to be in the vapour of phosphorous acid, which
first attacks the teeth and then the jaws through the
sockets. The persons most liable to this disease are
the dippers, in consequence of their standing for hours
together over the heated slab upon which'the phos-
phorus composition is spread. It appears from
medical evidence that a continued and uninterrupted
occupation in an atmosphere highly impregnated with
phosphorus fumes is a necessary condition in the pro-
duction of the jaw disease; but that if the factory be
well and abundantly ventilated, cleanliness in the
work-people enforced, together with attention to diet,
no evil consequences ensue. In the factory which
we have visited the workpeople are required to wash
their hands night and morning in a solution of soda ;
the dippers wear sponges before‘their mouths, and an
accumulation of fumes is prevented by numerous
open windows, fan-lights and ventilating shafts. The
gentleman who conducted the writer over the factory
evidently took an honest pride in pointing out the
abundant provision for ventilation, and the healthy
appearance of the men, boys and girls. One man
had been employed in the mixing room for 13 years,
a dipper had been at work 10 years, a girl employed
in tipping fusees 8 years, other girls 4'.‘ years, and so
on. We were assured that not a single case of jaw
disease had occurred, that the people were unusually
healthy, as indeed the appearance of the majority
seemed to testify. The only part of the factory that
was decidedly oppressive was the drying room, which
is kept at a temperature of about 90°, and was full of
fumes. ‘There are, however, only two boys employed
here; one to take the frames in to ‘dry, and the other
to fetch out when dry. '
There are factories in London less happily distin-
guished than Mr. Hynam’s, where the jaw disease is
known, as‘ our hospitals can testify. It is stated by
medical men that such factories are deficient in the
excellent precautions which‘ we have enumerated.
We regret this, because as it is clearly the duty of
every employer to protect his work-people from
injury, as‘far as lies in his power, the neglect of such
duty becomes positively sinful, if the means of salu-
brity be pointedhout, and he neglect to adopt them.
The allotropic phosphorus noticed in our Intro-
ductorj/ Essay, p; cxxxviii, does not appear to have
yet found its way ‘into the lucifer-match factory. If
it could be successfully applied, it would get rid of all
the objections to the use of phosphorus; but we
should be sorry ‘to see this-remarkable form of ‘phos-
MATRIX—MECHANICS—MEDAL~—MERCURY.
. 2457
phorus used as an excuse for neglecting efficient-
ventilation, without which no workshop, factory,
schoolroom, parlour or bedroom, or any other similarly
enclosed space, can be aZfit habitation for man or beast.
MATRASS, a glass chemical vessel with a thin
oval bottom, used for the purpose of digesting, boiling,
and distilling. In the last operation, one matrass
\J
\


Fig. 1426.
may be used as the body, and another as the receiver.
Florence flasks make excellent matrasses. _ Fig. 1426
shows three useful forms of matrass : the centre one
is flattened a little at bottom.
MATRIX. Metallic ores are usually associated
with stony substances, which form what is called the
matrix or gcmyue. The earl/‘lay Ir/mzgaes are usually
quartz, felspar, limestone, carbonate of barytes, sul-
phate of lime, sulphate of barytes, and fluor spar.
In some cases, ores become gangues with respect to
more precious metals, forming what are called metallic
gangues, such as iron pyrites, spathose iron ore, oxide
of iron, hydrate of iron, and blende. [See GANGUEJ
The mould used in type-founding, is also called the
mali'ia'. See PRINTING.
MATTE, the crude black copper, reduced but not
refined from sulphur and other substances. See
Corrnn.
MEAD, a favourite drink of the early inhabitants
of the British Islands, and probably the only strong
liquor known to them during a long period. It is
made with honey mixed with water and fermented.
MEAL, the edible part of wheat, oats, rye, barley,
and pulse of different kinds ground into a kind of
coarse flour.
MEASURES. See Wnrenrs and MEASURES.
MECHANICAL POWERS. See STATICS.
MECHANICS is the science which treats of the
actions of bodies on one another, either directly or
by means of machinery. These actions may be simple
pressures without motion, as when one body being
supported, another is placed upon it, either vertically
or in some oblique position. The actions may be
accompanied by motion, either from the mutual
attractions which all bodies in nature exert upon
each other, or from the collisions of bodies in motion
with others, which may be previously in motion or at
rest. When these actions refer to solid bodies, the
phenomena are discussed in those subdivisions of
Mechanics termed STATICS and DYNAMICS, under
which heads they will be briefly noticed. When they
refer to fluids, they belong to the subdivisions HY-
DROSTATICS and HYDRAULICS, to which we refer.
When they relate to airs, they are treated of under
PNEUMATICS. See Aln—eBarroan-zrna.

MECONIC ACID. See OrrUM. < -
MEDAL, a coin struck or cast for some special
purpose, such as to commemorate a victory, treaty,
coronation, or other event, or in honour of some distin-
guished person. The words mealeglie and mezleglioize
first occur in Italianwriters, and from them the English
and French get their medal and yizéclaille. The word
is supposed to be from the Greek pel'rahhov, metal, of
which medals are always made. The metal used is
generally bronze, [See Baoivzu] and the press in
which they are stamped is similar to the coining-
press. [See Cornrnea] A medal of extraordinary size
is called a medallion.
MEERSCHAUM. .See MAGNESIUM.
MENSTRUUM, the vehicle by means of which
bodies are rendered liquid. See SOLUTION. 1
MENSURATION is the art of finding any dimen—
sion of a figure, or its area, or surface, or solidity, &c.
It is one of the applications of arithmetic togeometry;
but only the simplest measurements that the case
will admit of are used. _ ,
MERCURY (Hg 100) is a brilliant white metal,
possessing the remarkable and peculiar property of
being fluid at common temperatures. This, together
with its resemblance in colour to silver, has led to
the terms fiyrli'argyrzmi, argerzzfzmi eivzmi, and quick-
silver applied to it. It becomes solid at—ét0°, in
which state it is malleable, flattens readily under the
hammer, and can even be struck into medals. At
lower temperatures it becomes brittle. Within the
arctic circle, the cold is often sufficiently intense to‘
freeze mercury. The readiest method of doing so
artificially, is by a solution of solid carbonic acid in
ether. A temperature sufficiently low for the purpose
may also be obtained by means of a mixture of
pounded ice and crystallized chloride of calcium.
In operating upon a small quantity of mercury in a
large platinum crucible, which must be gradually
cooled in successive freezing mixtures, the mercury
may be obtained in a crystalline form. When the
mercury has formed a solid crust, which adheres to
the crucible, the fluid mercury in the interior is
poured off, and the interior will be found lined with
sharp brilliant crystals, which are regular octahedrons.
When frozen mercury is brought into contact with
the skin, it abstracts the heat very rapidly, destroys
the vitality of the part, and produces the effect of a
burn. Mercury contracts considerably in solidifying.
At a temperature a little below freezing point, its
density is 1454.1 .At 32° its density is 13'596; at 60°,
13'568. It boils and becomes vapour at about 660°,
and the density of its vapour is 6976. It emits
vapour at all temperatures above 400. The volatility
of mercury at ordinary temperatures, may be made
evident by placing a daguerreotype plate several
inches above a vessel containing mercury. If the,
plate has been previously iodized, and submitted to;
the action of light in the camera, the picture will
be developed by the vapour of mercury at ordi-_

(I) Mr. Phillips in his Manual of Metallurgy gives 15131.? as the
sp.gr. of frozen mercury. - -
2418
MERCURY.
nary temperatures. The globules of mercury which
condense in the upper part of the Torricellian
vacuum of barometcrs, are a further proof of the
volatility of mercury. It has been supposed that
below 410°, the elasticity of mercurial vapour is scarcely
sensible, for if a strip of gold leaf be suspended in a
bottle containing a little mercury at the bottom, and
be kept at temperatures ranging from 40° downwards,
the leaf will not be whitened by the action of the
mercurial vapour, except a few lines above the surface
of‘ the mercury! the rest of the leaf will preserve
its characteristic yellow colour. Above 40° it will
be converted into an amalgam. According to Brame,
sulphur in the very finely divided utricular condition
in which it is first precipitated from the state of
vapour, is a much more delicate test of the presence
of mercurial vapour than gold leaf; for by its means
he finds that at 12° the vapour of mercury rises to a
height of more than a metre, and that even at 8°, it
appears to have no limited atmosphere, and that it rises
at ordinary temperatures from amalgams and mercu-
rial ointment. The following fact, as stated by
Burnett, (Phil. Trams. 1823,) shows the danger
arising from exposed metallic mercury. Part of the
cargo of a ship on the Spanish coast was mercury
contained in bags, which becoming rotten, the mer-
cury escaped into the hold, where it mixed with
the bilge-water; an elastic fluid was consequently
formed, which covered the _ metal on board with
quicksilver, ‘and affected the whole ship’s company
with violent ‘symptoms of salivation. We hare
also heard of the health of a whole family being
seriously injured in consequence of a quantity of
mercury spilled on the floor by a former tenant,
finding its way’under the boards, where it was left
until discovered by the medical attendant of the
family referred to. -
When pure mercury is shaken up with water,
ether, or oil of turpentine, or rubbed with sulphur,
sugar, chalk, lard, conserve of roses, &c., it is reduced
to a state of minute division, forming a grey powder,
which unites with the foreign body, and in some -
cases, all appearance of the metal is lost. In well
made mercurial ointment, the globules of mercury
cannot be distinguished by the naked eye, for accord-
ing to Ehrenberg, they are not more than from gg-Oth
to lolooth of a line in diameter. It is highly probable
that the eflicacy of mercury as a medicine, depends
upon this state of mechanical division, and not to any
chemical combination with chalk, lard, conserve of
roses, &c., which merely serve as vehicles for the
minute globules, and prevent their rurming together.
In its ordinary state, mercury is inactive as a medicine,
but in the minutely divided state, in which it ‘exists
in mercurial ointment, blue-pill, izydrmyyrum cam
eree‘ci, &c., the mercury is absorbed, and becomes
active. The energetic action of mercury on the
animal system, is shown by the nervous tremblings,
salivation, and other morbid effects which it- produces
an the workpeople, whether in the mine or the factory,
who are constantly or frequently exposed to it. And
here again we see that mercury is energetic in conse-

quence of the production of vapour, whether at ordi-
nary temperatures or at a furnace heat.
Mercury is imported into this country in leathern
bags, and also in bottles of hammered iron, containing
60 or 7 0 lbs. each. In this state the metal is very
pure, but when purchased in smaller quantities, it is
sometimes found to be adulterated with tin, lead, or
bismuth, which metals are readily dissolved by mer-
cury without much loss of fluidity. The fraud can
be. detected by subliming a little of the mercury in
an iron spoon, when a residuum is left, which is not
the case with the pure metal. Pure mercury does
not adhere to glass or porcelain, but rolls upon those
substances without leaving any trace; but when it
contains foreign metals, it adheres to those surfaces,
and in pouring leaves a train or rail behind. The
pure metal forms spherical globules if moved about
on glass, the adulterated mercury forms elongated
tears covered with a grey pellicle, which adhere to
the surface.
Mercury is of great value in the construction of phi-
losophical instruments, on account of its fluidity, its
great density, and the regularity of its expansion and
contraction under the influence of increased and
diminished temperatures ; hence it is preferred to all
other liquids for filling thermometer and barometer
tubes, but for these purposes it ought to be pure.
We will therefore describe somewhat minutely the
various methods of purifying it. Onemethod is to
distil it, for which purpose one of the bottles in
which it is imported may be used. It should be half
filled with mercury, some clean iron or copper filings
added, and the mouth fitted with a curved iron tube,
to the further extremity of which is tied a tube or
hose, formed of a number of folds of linen or cotton
cloth. The end of the hose is to' dip into a vessel of
water, and a stream of water is also to be directed
down the hose, as shown in Fig. 14127. On applying
heat to the iron bottle, the mercury boils, and_disen-


Fig. 1427.
gages its vapour with much jerking of the retort, and
care must be taken to regulate the heat, so as to
prevent the metal from being projected from the
bottle. The greater portion of the foreign metal
remains in the bottle, but some of it is dragged over
with the vapour, and, indeed, if the mercury be con-'
taminated with zinc, it will distil over with it.
The purification of mercury by distillation being
thus imperfect, other modes have been adopted. The
'mercury may be treated with common nitric acid
MERCURY.
24.49
diluted with about twice its volume of distilled water,
and then heated to about 110°. Nitrate of the pro-
toxide will be formed, and this, and the free acid, will
react on the foreign metals, which are held in solution
in the form of salts: any oxide of mercury is also
dissolved. The action is continued, with occasional
stirring, for 24: hours. The water is then separated
by evaporation, and the nitrate, which forms a crys-
talline crust on the surface of the metal is removed.
The metallic mercury is separated, washed with
distilled water, dried with blotting-paper, and if
necessary, placed under a glass containing a little
quick lime, which completes the drying.
If the mercury is merely contaminated with oxide
it may be cleansed by putting from half an inch to
an inch in depth into a large earthenware pan, and
pouring over it sulphuric acid diluted with twice its
weight of water. This is allowed to remain for a
week, being often agitated during that time: the
metal and the acid are then separated, and the former
washed, dried, and cleansed mechanically. A little
sulphate of mercury assists the action of the sulphuric
acid on the metal. Mercury may also be purified
from dust, dirt, thin films of oxide, and other mecha-
nical impurities, by folding a piece of paper into the
shape of a cone or funnel, and passing the mercury
through it. The opening at the bottom should be
extremely small, but capable of being easily regulated:
by pulling the inward fold upwards it increases the
aperture below; but by pulling the outer fold upwards
a little it tends to close it. The aperture may also
be opened or closed more or less by the finger. The
mercury, running through this cone into a glass vessel
placed to receive it, leaves behind a quantity of scum
and other extraneous matters : these abound so much
in the latter portions of the mercury, that it is better
to reserve these in the cone, and put them away for
further purification. This simple method is sufficient
for general purposes, where the impurities are merely
adhering dirt, but other methods are likewise em-
ployed, such as filtering through the pores of a piece
of hazel-wood by atmospheric pressure, or squeezing
through chamois leather. After all, a‘ film generally
remains on the surface, but this may be greatly les-
sened by putting some powdered loaf-sugar into a
bottle with the mercury to be cleansed, and agitating
them well together. The effect is assisted by breathing
into the bottle several times to give moisture, which
causes the sugar, when agitated, to adhere better to
the dirt present. After this the mercury is poured
through a paper funnel, and is found comparatively
clean.
Where small quantities of mercury have to be
acted on, they may be purified by a simple process
employed by Dr. Priestley, and which we shall describe
in his own words :--“I take a glass phial with a
ground stopper, (such being generally pretty strong)
and fill about l-fourth of it with the foul quicksilver;
then, putting in the stopper, I hold it inverted and
shake it violently, generally striking the hand that
supports it against my thigh. When I have given it
20 or 30 strokes in this manner, I take out the stop- ‘

per, and blow into the phial with a pair of bellows,
which I do in order to change the air, knowing that
the purer the air the faster the process advances.
After a short time, if the mercury be very foul, the
surface will not only become black, but a great quan-
tity of the upper part of it will be, as it were, coagu-
lated, so as to be easily separated from the rest. I
therefore invert the phial, and covering the mouth of
it with my finger, let out all the mercury that will
flow easily, and put the black coagulated part into
a cup by itself. This I press repeatedly with the end
of my finger till I make a complete separation of the
running mercury from the black powder; and putting
the powder by itself, I pour back the mercury to the
rest of the mass out of which it was taken, in order to
be agitated with it again. This process I repeat till
I find that no more black matter can be separated;
and it is not a little remarkable that the operator will
be at no loss to know when the process is completed.
For the same quantity of lead seems to come out of
it in equal times of agitation, and consequently the
whole becomes pure at once. Also, whereas, while
the lead was in the mercury it felt, as I may say, like
soft clay, the moment the lead is separated from it,
it begins to rattle as it is shaken, so that any person
in the room may perceive when it has been agitated
enough.” By subsequent distillation it was ascer-
tained that mercury is perfectly purified by the above
process.
Mercury is acted on very unequally by the mineral
acids. Hydrochloric acid scarcely attacks it even
under the influence of heat ; nor has dilute sulphuric
acid any action on it; but in its concentrated form,
this acid, heated, forms with mercury a sulphatewith
disengagement of sulphurous acid. Nitric acid
attacks mercury at all temperatures, and when the
acid is diluted binoxide of nitrogen is disengaged.
By continued exposure to the air mercury absorbs
a small quantity of oxygen at ordinary temperatures ;
but the oxide is mixed or dissolved with a large quan-
tity of mercury, and forms on the surface a grey
pellicle which adheres to glass. The oxidation pro-
ceeds much more rapidly at the boiling point of mer-
cury. By keeping mercury in a state of slow ebullition
in a matrass with a long neck open to the air, the
real oxide of mercury, formerly called reel precipitate,
is produced under the form of small prismatic crystals.
Two combinations of mercury with oxygen are
known. One is the snoorrz'cle or black oxide, I'IgzO,
which is not a very stable compound although it forms
with acids salts which crystallize readily. It may be
obtained by precipitating one of these salts, the nitrate
for example, by means of caustic potash: the black
precipitate which is formed decomposes spontaneously
into red oxide and metallic mercury. By rubbing
this black powder in a mortar for some time, metallic
mercury is produced: this decomposition is more
rapid at the temperature of 212°, or even at the
ordinary temperature under the influence of the solar
rays.
The [n'oz‘oc'z'cle or reel oaz'rle of mercury, HgO, is
formed, as ah'eady noticed, by exposing the metal to
250
r/mncunr,
a high temperature in contact with air. But this plan
is very slow in operation, and scanty in results. It
may be more abundantly produced by decomposing
nitrate of mercury HgO,N05, at a heat sufficient to
decompose and expel the acid. It may also be
obtained by calcining the nitrate of the suboxide
Hg20,N05, but the appearance‘ of the product
varies according to the kind of nitrate used. Thus
the nitrate of the protoxide in small crystals furnishes
a crystalline oxide of mercury of a brick-red colour,
and the nitrate of the suboxide gives an oxide of an
orange-yellow. By pouring caustic potash into a
solution of nitrate of the protoxide of mercury a yel-
low precipitate of the‘ oxide is formed which is an-
hydrous. A solution of corrosive sublimate may also
be used for this purpose. The red and yellow oxides
are isomeric, and in some chemical reactions behave
dilferently. The yellow oxide is more easily attacked
by chlorine than the red, and it also combines, at
ordinary temperatures, with oxalic acid, which is not
the case with the red oxide. The red oxide is slightly
soluble in water, to which it imparts an alkaline re-
action and a metallic taste; it is very poisonous: it
is decomposed by heat, producing metallic mercury
and oxygen gas. Indeed, it was by means of this
substance that oxygen gas was discovered by Priestley,
and that Lavoisier afterwards showed the composition
of atmospheric air. The red oxide is sometimes adul'
terated with red lead; by placing the powder 011 a
red-hot iron, the mercury will be entirely dissipated,
but the lead will remain.
It has been already stated that nitric acid acts with
facility on mercury, but the action varies with the
temperature, and the strength of the acid. When
cold and somewhat diluted, salts of the grey oxide
are formedgand these are neutral or basic, (5.0. with
excess of oxide,) according as the acid or the metal is
in excess. With hot concentrated acid, the mercury
is raised to its highest state of oxidation, and a salt
of the red oxide is produced. Both classes of salts
are liable to be decomposed by a large quantity of
water, giving rise to insoluble or sparingly soluble
basic compounds. The neutral sadm'trate of mercury,
Hg2QNO5—l-2HO, is formed by dissolving mercury
in an excess of cold dilute nitric acid; it forms large
colourless crystals soluble in a small quantity of water
without decomposition. With an excess of mercury
a finely crystallized basic salt is deposited, containing
3EiggO,2NO5—l-3HO, which is also decomposed by
water. The two salts may be distinguished when
rubbed in a mortar with a little chloride of sodium;
the neutral compound gives soda and calomel; the
basic salt, nitrate of soda and a black compormd of
calomel with oxide of mercury. When ammonia is
dropped sparingly into a solution of subnitrate, a
black substance is produced, called Haizaemaaa’s
soZaZ/‘Ze mercury]. When red oxide of mercury is dis-
solved in excess of nitric acid and gently evaporated,
a syrupy liquid is obtained, and if the vessel contain;
ingit be placed over another vessel containing lime
or sulphuric acid, and the whole be covered with a
bell jar, voluminous crystals and crystalline crusts

will be obtained; their composition is 2Hg0,
NO5+HO. There are other methods of forming
this compound, which is decomposed by water into
other and more basic com pounds. Nitrate of mercury
is used in the arts as a wash for rabbit and hare skins :
it imparts to their furs the property of felting, which
does not naturally belong to them.
Nitrate of mercury is also the source of falmz'aatz'ag
powder, the mode of preparing which will be given
under Pnncussron cars.
When sulphuric acid is added to a solution of the
subuitrate of mercury, a saZp/zate of zf/ze saboa'z'a’e
Hg20,803, is formed: it is a white crystalline
powder, only slightly soluble in water. By boiling
together equal weights of sulphuric acid and mercury
the latter is wholly converted into a heavy white
crystalline powder, which is the sulphate 0f the
protoxide, Hg0,S03. The excess of‘ acid may be
removed by evaporation. This sulphate is decom-
posed by water, which dissolves out an acid salt and
leaves an insoluble yellow basic compound, formerly
called tamed/z or tarbz'zf/r mz'aeral. By long continued
washing, the remaining acid is removed, and pure
oxide of mercury left.
The compounds of mercury and chlorine are of
importance in medicine and the arts. The subclzlorz'de,
or calomel, HggCl, may be, as Fownes remarks, well
prepared by pouring a solution of the subnitrate into
a large excess of a dilute solution of common salt.
It falls as a dense white insoluble precipitate, which
must be well washed with boiling distilled water and
dried. But the actual method of forming calomel is
more complicated. Dry sulphate of the red oxide is
rubbed in a mortar with as much metallic mercury as
it ah‘eady contains, and a quantity of common salt,
until the globules disappear, and the mixture becomes
uniform. This mixture is then sublimed in an
alembic, but instead of the usual head to that appa-
ratus, which would collect and condense the calomel
into a solid mass, the vapour of the calomel is carried
into an atmosphere of steam, or into a chamber con—
taining air, by which means it is condensed in a
minutely divided state and the laborious process of
pulverising avoided.1 The reaction is thus explained
by Fownes :—
1 equivalent of sul- calomel’ Hgzcl'
phate of mercury 1 eq' oxygen
1 eq. sulphuric acid
1 equivalent of metallic mercury lequivalentofcom- 1 eq. chlorine ....... ..
mon salt............ 1 eq. sodium’.........
{1 eq. mercury ....... ..

Sulphate of soda.
Calomel, when pure, is 'a heavy, white, insoluble,
tasteless powder: in the solid-state it 'phosphoresces
when scratched or broken in the dark: it sublimes
below ared heat. ' It is immediately decomposed by an
alkali or by lime water and the suboxide produced.
It is insoluble in cold dilute nitric acid: but the acid
when hot and strong oxidizes and dissolves it.
Calomel is apt to contain a little corrosive sublimate,
which 'is dangerous in a substance used so largely in

(1) A patent was taken out by Dr. A. T. Thomson, in 1843, for‘
the manufacture of calomel and corrosive sublimate, by directly
combining the vapour of mercury with chlorinrx '
MERCURY.
251
medicine; it may be detected by boiling in water,
filtering and adding caustic potash, when the presence
of corrosive sublimate is indicated by a yellow pre-
cipitate. '
A native chloride of mercury, the lwrri quicksilver
of the mineralogist, is found at Almaden in Spain, and
also at Moschellandsberg in the Palatinate. It is of
a greyish white or yellow colour, and has a conchoidal
fracture. At the latter mine it covers the surface of
a ferruginous gangue, and in some cases affords a
distinct crystal belonging to the right prismatic
system. This mineral is occasionally found at Idria
and also in Bohemia.
C/zloricle of mercury, or Corrosive sublimate, I-IgCl,
may be obtained by various processes. Its formation
is often shown at the lecture table by heating a globule
of mercury in a deflagrating spoon and plunging it into
a bottle of chlorine ; the metal takes fire and produces
the chloride. By dissolving the red oxide in hot
hydrochloric acid, the chloride crystallizes on cooling.
But the usual plan is to sublime a mixture of equal
parts of sulphate of the red oxide of mercury and dry
common salt. The decomposition is thus given by
Fownes :—
1 eq. mercury ....... .. Corrosive sublimate.
1 eq. sulphate
of a: is
1 eq. common leq. chlorine ....... ..
salt ....... .. 1 eq. sodium ....... ..
Corrosive sublimate is a white, transparent, crys-
lalline mass of great density; it fuses at 590°, and
boils and volatilizes at a somewhat higher tempera-
ture. It is soluble in 16 parts of cold and 3 of
boiling water: it crystallizes from a hot solution in
long white prisms: it is also soluble in alcohol and
ether, and the latter will even withdraw it from its
aqueous solutions. It combines with other metallic
chlorides, forming beautiful double salts. It absorbs
ammoniacal gas rapidly. When an excess of solution
of ammonia is added to a solution of corrosive subli-
mate, a white insoluble substance is thrown down
named zv/zile precipitate. Several compounds of chlo-
ride of mercury with oxide of mercury are formed by
adding an alkaline carbonate or bicarbonate, in vary-
ing proportions, to a solution of corrosive sublimate.
Corrosive sublimate forms insoluble compoimds with
many organic substances which contain nitrogen, such
as albumen. The great antiseptic virtues of corrosive
sublimate may be due to this property: by its means
animal and vegetable substances are preserved from
dry~rot and decay, as in Kyan’s method of preserving
timber and eordage. The formation of insoluble
compounds with albumen renders white of egg a good
antidote to corrosive sublimate in cases of poisoning.
Mercury and iodine unite in two proportions. The
saeicvlicle, HggI, is formed when a solution of iodide
of potassium is added to nitrate of the suboxide of
mercury; it separates as a dirty yellow greenish
insoluble precipitate. The iollirle, HgI, is formed
by mixing a solution of iodide of potassium with
chloride of mercury; the precipitate is at first
yellow, but it quickly changes to a brilliant scarlet,
which colour is retained on 'This, which is
Sulphate of soda.

the neutral iodide, may be procured, but of a duller
tint, by triturating single equivalents of iodine and
mercury with a little alcohol. The iodide is dimor~
phous and the colour is red or yellow according to
the figure. When the iodide is suddenly heated it
becomes bright yellow throughout, and affords a
copious sublimate of minute brilliant yellow crystals.
If in this state it be touched by a hard body, it in-
stantly becomes red, and this change takes place
spontaneously after an interval. By a very slow and
careful heating a sublimate of red crystals of a totally
different form may be obtained, and these are per-
manent. An iodide of mercury has been found native
in some of the Mexican mines; its colour resembles
that of cinnabar, but is deeper.
The compounds of sulphur are important. When
1 part mercury is triturated for some time with 3 of
sulphur a black tasteless compound is obtained, which
was formerly called Elliiops mineral. It is doubtful
whether this is a definite sulphuret. The sabsalpfiarel,
HgrS, is formed when sulphuretted hydrogen is
passed into a solution of subnitrate of mercury. The
black precipitate thus produced is decomposed by
heat into metallic . mercury and neutral sulphuret.
The salplzarcl of mercury, artificial cirmal/ar or vermi-
lioa, HgS, is most easily prepared by sublirning an
intimate mixture of mercury and sulphur. As this-
substance is of importance in the arts, we will give
examples of the various methods of preparing it.1
When 5 or 6 parts of mercury are added to one part
of melting sulphur, and the mixture heated with
constant stirring till the sulphur becomes thick, com-
bination takes place suddenly, attended with evolution
of light and heat, and with violent crackling and pro-
j ection of the mass. The resulting compound exhibits
a blackish-red colour, and frequently a distinct red
streak; it may be regarded as cinnabar partly mixed
with black sulphide2 of mercury, and partly with
uncombined mercury and sulphur in a state of minute
division. Now, when this crude product, after being
pounded, is mixed with a small quantity of sulphur,
and a glass flask half filled with it is loosely closed
with a charcoal stopper, sunk to two-thirds of its
depth in sand, and exposed for some hours to a red
heat in a slow-drawing wind-furnace, a sublimate of
pure cinnabar is obtained. The excess of sulphur
being more volatile than the cinnabar, escapes;
foreign metals remain in the form of sulphides at the
bottom of the flask. If the upper part of the flask
becomes too bet, a portion of the cinnabar may be
lost by volatilization. The old method of preparation
in Amsterdam is to add gradually 170 pounds of
mercury to 50 pounds of melted sulphur contained
in a cast-iron pot, the materials being stirred up with
an iron spatula, but not so rapidly as to give rise to
active combustion—the mixture poured out upon an
iron plate, and broken into pieces after cooling—and
the fragments put into hand-jars capable of hold-

(I) These examples are selected from the very full notice of
Mercury contained in Gmelin’s Chemistry, vol. vi. of the Caven-
dish Society’s Translation, 1852.
(2) The term sulphide is now commonly used instead of szvzl
plmi'et.
252
' MERCURY.
ing 1% lb. of water. The subliming vessels are
earthen cylinders 4 feet high, glazed within and closed
at the bottom; they are sunk to two-thirds of their
depth in a furnace in which their lower part is heated
to redness. A few hand-jars full of the mixture are
thrown into each of these subliming vessels, and the
contents left to crackle and burn, till the greater part
of the excess of sulphur volatilizes, and the flame
diminishes. The smooth level opening is then covered
with a thick, smooth plate of cast-iron; the plate
removed as soon as a sufficient quantity of cinnabar
has collected upon it; the cinnabar which has col-
lected on the upper part of the vessel pushed down
again; a- fresh plate put on, &c. The contents of
the cylinder are stirred up from time to time, and
fresh ‘material introduced. The cinnabar, after being
detached from the plates, is ground as finely as
possible with rainjwater.
The method of preparation in Idria is to procure a
number of casks, and place in each 8 pounds of
pounded sulphur and 42 pounds of mercury. The
casks thus charged are made to turn upon their axes
for two or three hours, till the contents are converted, '
with slight evolution of heat, into a brown powder.
100 pounds of this powder are then introduced into
an upright cast-iron cylinder, previously heated in a
furnace; the cylinder covered with an iron capital,
kept down by weights till the crackling of the mass
is over; the iron capital thereupon replaced by one
of stone-ware, having its beak connected with a tube
and receiver, and the fire increased. The best cin—
nabar collects in the capital, which is afterwards
broken in pieces; that which condenses in the tube
and receiver, if mixed with excess of sulphur, is
added to the quantity introduced at the next subli-
mation. The cinnabar, after being finely ground
with water, is well boiled with potash-ley and washed
with boiling andwith cold water.
The Chinese method is to sublime 1 part sulphur
and 4 parts mercury in an earthen vessel, to which an
iron cover, kept constantly moist, is luted; the fire
is kept up for 24 hours; the vessel broken up after
cooling; the less pure sublimate separated; the purer
portion pounded up, and the powder sifted into a
large vessel filled with water; the water with the
scum floating on it poured off after a while, the
process being twice repeated; and lastly, the sedi-
ment at the bottom is dried. European cinnabar,
whether prepared in the dry or in the humid way,
always has a tinge of yellow; the Chinese, which is
six times as dear, inclines to carmine colour, although
no foreign matter can be detected in it, excepting a
little glue. By the sublimation of common cinnabar
with 1 per cent. of sulphide of antimony, a dark
steel-grey cinnabar is obtained, which becomes brown-
red when pulverized; but if it be finely ground, and
repeatedly boiled with a solution of liver of sulphur,1
then, thoroughly washed and digested with hydro-
chloric acid, and afterwards washed and dried, it

(1) Compounds obtained by fusing potash or its carbonate with
“sulphur were formerly called livers_of sulphur, in consequence of
their colour.

becomes ‘exactly like the Chinese Vermilion, but of a
still finer colour. No antimony can be detected in it.
The chief point to be attended to in the preparation
of cinnabar by sublimation is, that no black amor-
phous sulphide get mixed with it.
We will now give an example or two of the method
of forming this pigment in the humid way, premising
that the black amorphous sulphide of mercury ob-
tained by the action of sulphuretted hydrogen, or of
alkaline hydrosulphates, or hydrosulphites,.on mercury,
its oxides and salts, is converted by contact with
alkaline hydrosulphites, slowly in the cold, but quickly
when heated, into the red sulphide. Brunner care-
fully triturates 100 parts of mercury with 38 parts
of flowers of sulphur, till the whole is converted into
Ethiops—a process which requires 3 hours for small
quantities, and 12 hours if the quantityamount to a few
pounds—and heats it in a porcelain basin, or a cast-
iron pot, with a solution of 25 parts of potash-hydrate
in 133 to 150 parts of water, keeping the temperature
uniformly at 45°, and never letting it rise above 50°.
At first, the mixture is constantly stirred with the
pestle, afterwards from time to time. The water
which evaporates is replaced, so as not to allow the
mixture to acquire the thickness of jelly. When the
reddening has once begun, which generally takes
place in about 8 hours, the heat must not be allowed
to rise above 45°; and as soon as the red has attained
its greatest degree of brightness, the vessel is re-
moved from the fire, or else, which is better, the
mixture is kept for some hours exposed to a gentler
heat. It is then washed, and the mercury which
remains metallic, separated by levigation, whereupon
it yields from 109 to 110 per cent. of cinnabar, but
little inferior to the finest native variety, and far
superior to that obtained by sublimation. The above
mentioned proportion of the ingredients gives the
largest amount of cinnabar. 100 parts of mercury
yield, with 40 parts of sulphur and 40 of potash-
hydrate, 107 cinnabar; with 283 sulphur, and 51
potash-hydrate, 942; with 33 to 40 sulphur, and 60
potash-hydrate, 815; and with 30 sulphur, .and 60
potash-hydrate, only 473 cinnabar.
Martins places the ingredients in bottles closed
with corks, and packs them in a box, which is fastened
to the upper beam of a saw-mill. In 24 or 36 hours,
at ordinary temperatures, the most beautiful cinnabar
is obtained; it is afterwards washed and dried. This
method not only has the advantage of dispensing with
the‘ labour of tritin'ation, but it likewise prevents the
hitherto unexplained passage of the cinnabar into a
brown state, which is so liable to take place on the
application of heat.
There are several modes of adulterating vermiliom
The substances employed are brick-dust, oxide of iron,
red lead, and dragon’s-blood. Brick-dust remains
behind on ignition, oxide of iron the same: it may
also be dissolved out by hydrochloric-acid. Red lead
remains behind on ignition in the form of a fused
protoxide, and yields chloride of lead with evolution
of chlorine on boiling the substance with hydrochloric
acid; it- may also be extracted by large quantities of
MERCURY.
253
boiling water. Dragon’s-blood produces an empy-
reumatic odour on the application of heat, and also
gives a red colour to alcohol.
In concluding this notice of the more important
salts of mercury, a few general characters may be
stated. The salts of mercury are all volatilized or
decomposed by ignition, and the metal produced either
by heat alone, or by the addition of a little dry car-
bonate of soda. The metal is precipitated from its
soluble combinations by a plate of copper, and also by
a solution of protochloride of tin in excess. Caustic
potash and ammonia give characteristic precipitates
with the chloride and soluble salts of the red oxide.
Mercury dissolves many of the metals with facility,
forming what are termed amalgam. [See AMALGAM.]
It is this property which renders mercury so valuable
in extracting gold and silver from their ores, and also
in the operations of gilding [see BUTTON], plating,
and the manufacture of looking-glasses, the silver-
ing of which, by amalgam of tin, is described under
GLASS, Section VIII. An amalgam of silver is em-
ployed for stopping hollow teeth.
We come now to notice the treatment of the ores
of mercury. Mercury is found native in fluid glo-
bules disseminated through the gangue, and some-
times accumulated in cavities, so that it can be dipped
up. The only ore of mercury, properly so called, is
the sulphuret: it has a dull red colour,-and leaves a
bright scarlet streak. It is mostly found in connexion
with talcose and argillaceous shale, or in some other
stratified deposit, usually inthe form of veins or lodes;
but when the matrix is sandstone, it is disseminated
in minute grains throughout the mass.
The chief mines which yield mercury are at Idria
in Austria, Almaden in Spain, in the Palatinate on
the Rhine, and in Peru. The metal has also been
fotuid in Hungary, Sweden, China, Japan, Mexico,
and Chili. At Idria, the sulphuret is worked in a
formation composed of a compact black limestone
associated with an argillaceous schist. The rock is
too friable to admit of large excavations, so that the
workings are carried on by means of small galleries.
The ore is chiefly bituminous cinnabar associated with
native mercury, and it is obtained at a depth of 850
feet from the surface. Native mercury is sometimes
so abundant that when the ground is first broken it
escapes in large globules which collect in the bottoms
of the levels. The pure metal is separated by filtra-
tion from earthy matters, which are mechanically
treated previous to roasting. The mines of Almaden
were known to the Greeks 7 00 13.0., and Pliny men-
tions them as yielding a large supply of mercury. The
vein varies from 1% to 16 yards in thickness : a black
slate, impregnated with metallic mercury, is also
worked. The mines do not exceed 300 yards in depth;
they are excavated in argillaceous schist and sand-
stone grit deposited in horizontal beds, which in some
places have been intersected by eruptions of granite
and black porphyry. The mines of the Palatinate are
of less extent than the Austrian and Spanish mines,
but like them, the government either works them on
its own account or farms them to private specu-

lators. The workings are numerous, and are situated
in various geological positions. The mines of Hun-
gary, Bohemia, and other parts of Germany, are of
small extent, not producing collectively more than
from 35 to 40 tons of mercury per annum. The pro-
duce of the Peruvian mines has hitherto been chiefly
employed in treating the ores of gold and silver.
In the treatment of the ores of mercury for the
purpose of extracting the metal, we will first notice
the plan adopted at Idria. The ores are divided into
two classes according to the size of the lumps, which
in the first class vary from the size of a nut to a cubic
foot, and in the second, from the size of a nut to the
finest dust. The ores in the first class admit of three
divisions, viz. the poorest species, which yield only
1 per cent. of mercury; the massive sulphuret with
the richest picked pieces, often containing 80 per cent.
of metal; and, lastly, the splinters arising from the
picking and sorting of the different ores, and which
yield from 1 to 40 per cent. There are also three
varieties in the second class, viz. small fragments
from the mine, which average from 10 to 12 per cent.
of metal; pieces of ore separated by washing on a
sieve, and containing 32 per cent. of metal; and lastly,
the fine sand and paste, called scfiZz'c/z, obtained by
stamping and washing the poorer ores: this yields
about 8 per cent.
These various forms of the mineral are subjected
to a high temperature in a distillatory apparatus. The
sulphur burns away as sulphurous acid gas, and the
mercury thus set free distils over, and condenses in
chambers prepared for the purpose. The kiln and
condensing chambers are represented in sectional ele-
vation and plan in the following figures. They form
together probably the largest metallurgic erection ‘in
the world, the length being 180 feet, and the height
30 feet. The ore, in large fragments, is piled upon
the vault v, It‘ig. 1428, which is pierced with a number




I
‘lit. ‘.
a
21%










.- _. x‘ v-_’.‘.. I £_ ...-..._.1t_..._.=‘_2:.- .Hk». __ _
—-~_ :9 ‘ i‘ 1
‘I .
l\
it . L
lllvévf , 1i’
"*v't' f:
,, {lit
'-: 'j ; _ ‘ _ _ _ ." . r ' J 34; i- =~.;, f‘ , h I I! I 1:’, "3‘: ‘i t ._. 1
| 4
k \ .x
Hi] I ry'z‘lls/ - y a b
i I
' ‘are _ r '
Fig. 1428. MERCURY SUBLIMING FURNACE AT IDRIA.
of openings, and the space above it is completely
filled. Smaller fragments are piled on the second
vault 22’, and upon the third vault v" is piled a number
of earthen pans containing the dust of the ore and the
slich. These pans are also used in the space above
'0' v'should the ore be very small. The furnace being
thus charged, a fire is kindled in the hearth r, and
the temperature ‘is gradually raised. The sulphuret
of mercury is exposed to the constant action of
numerous currents of air, which pour into the spaces
25 a '
MERCURY.
above 22 a’ through a number of small holes made
through the sides of the furnace, and opening into the
galleries ea’. As the ore is decomposed under the
oxidising action of the air, the mercurial vapours




~ ;<~\\ .;s\\
a. \‘\'\v&\ \\\\_Kfl\ “Rub >\


tai: ‘(52 iii? \




I.
*- r
if,‘ ..
I" ,l - V l.
. fit .‘
l .- l
I,“ i f
’ ll ‘
s, Lll | v
.41"; ii l
\ r
I l
I g ‘I.
i r p :i ‘c
\\\\>il
'“Imi ‘\vs


.\ .\.\


ll
lit v" 7 i i
| \ \\ i r/ i
w—



i /



a WT










/_/
Zas¢ was
7 -_—_.


7 Fl, =, /
.1 - li‘“ .9’ \-—-" 3’
Figs. 1429, 1430.


ROASTING KILN AND CONDENSING CHAIM'BERS
AT IDRIA.
escape into the condensing chambers o1 02, 850.
Most of the mercury condenses in the first three
chambers, whence it flows by gutters g g’ into a
covered reservoir below the level of the floor. In
the other chambers 04 G5, a large quantity of water and
yerydittle mercury are condensed, and as this mercury
is mixed with a good deal of dust, it is collected by
separate gutters, and is afterwards purified by filtra-
tion, the residue being returned to the furnace at a
subsequent charge. Whatever vapour of mercury
escapes into the last chamber 06, is condensed by
means of a current of water falling down inclined
planes, which project from the walls, as shown in Fig.
1429, and whatever vapour and gas escapes this




V] / égiié V ' / i
”//////////////////./ /
l
-.

, cw a. ~
/ //////////////////////%///////////
The kihl is charged in 3 hours by the united labour
of 40 men. Beechwood is usually employed as fuel,
and the distillation lasts from 10 to 12 hours, dru'ing
which the furnace is kept at a cherry-red heat. A
full charge for the double apparatus requires from
1,000 to 1,200 quintals of ore, which produce from
80 to 90 quintals of metallic mercury. The furnace
takes 5 or 6 days to cool, so that allowing time for
charging and withdrawing the residue, only one dis-
tillation can be made in the course of the week.
This furnace was erected in 1794!, previous to which
an aludelle furnace, next to be described, was em-
ployed.
The march of improvement is more slow paced
in Spain than in Austria, so that in the former
country the old dag/£70226 or aludelle furnace still
continues to be used. It is more imperfect in its
action, and consequently more injurious to the health
of the people employed, than the Idrian arrange-
ment. It consists of a circular or polygonal chamber,
0 c’, Fig. M31, divided into two compartments by a
brick vault v furnished with apertures. The ore is
piled up on the vault, first in large fragments, then
in smaller ones, and the whole is covered with soft
bricks formed of clay, the finer parts of the ore, and
the disintegrated residue of previous operations. At
the upper part of c’, are openings 0, which com muni-
cate with a number of adapters or pipes fitting into
each other, so as to form a long channel upon the
terrace '1‘. These adapters are called aZarZeZZes, and
are represented on . . a larger scale in h Fig. 1433. They
are thrust into each other, and luted at the joints
with softened loam. The mercury condenses in the
aludelles, and a portion remains
there, but the larger portion es-
capes by a hole pierced in the
under part of the lowest of the
series, and escapes by the gutter
g into the reservoirs M‘. The
gas mingled with the uncondensed
mercurial vapour passes into the
shaft s, and accumulates on the
walls in the form of mercurial soot,
which is swept down from time to
time, filtered to' separate metallic
mercury, and what is left is
kneaded into the bricks which are
used to cover the top of the charge.
The fuel, which usually consists of
brushwood, is'introduced by the
opening 0 into 0, the smoke es-
caping by s. The fire is kept up
for 12 or 13 hours, after which


, --._ I ~>‘_‘v s1
Fig. 1433.


//'
Figs. 1431,1432. ELEVATION AND PLAN or SPANISH ALUDI-JLLIE FURNACE.
action is then discharged into the air. The mercury
is filtered through thick linen bags, and then packed
in wrought-iron bottles for exportation.



the kiln is left for 3 or 4r days to
cool. The kiln is then cleared
out, and a fresh charge introduced
through the door 65. Z is a'fiight
of steps leading to the furnace, and w a pipe'for
carrying off water. '
In the Duchy of Deux-Ponts, in the Palatinate,
MERCURY—~METAL.
255
the ore, which is of a mixture. of cinnabar and calca-
reous rock, is roasted in a kind of earthern retort
3, Fig. 14:34‘, to the mouth of which is luted an















k the necks of the
retorts ; and the
f/fl/Wf/ii-ilill . x / A receivers are
\\\\\\\ \ _\\\\\\\\\\\\\\\\\\\\\\‘ arranged on
Fig. 1434. rurinacn USED IN THE PALA~ SllelVCS OU-lZSlClE.
TINATE- In this case the
sulphuret of mercury is decomposed by the lime, with
the formation of sulphuret of calcium and sulphate of
lime, and the liberated mercury condenses in the
receivers. Pit coal is the fuel used.
About the year 1847, a form of apparatus closely
resembling that used in the manufacture of gas from
bituminous coal, [see Gas] was erected under the
superintendence of Dr. Ure at Landsberg in the
Bavarian Rheinkreis. It consisted of a series of
retorts r, llig. 1435, set in masonry, and fitted at one
as V earthern re-
? WW . ‘
W’ifdwfiéjee‘era, ceiver r con
'7/ lIlllll taming watei.
""341" d: I '!ll
as nmnr npr are unnnn% The retorts are
11mins..- ‘mm! manna mnnnnrun .
‘ Hfilllllllilli'tumfgnmhfllmll%ll,lllnmmmm arranged in a
. ‘ ' w») \x' v V i ,-
gallel‘y furnace
lllllflmumlg$iéfl “ llll l“ “ in the side walls
l lllllfilfi I '
m1 mllllllll piggy; l of whlch open-
unnnnni ings are left for
it y ,




lilrllill
Hula;
44‘ Q)’
o __ ,—








\\\\\\\\\\§\ “
§\\ ,5
end with an eduction tube e, and at the other with
an air-tight stopper kept in place by an iron screw.
The eduction pipes are each furnished with a nozzle
a, closed by a screw plug, and used for introducing a
wire to clear
away any ob-
struction aris-
ing from adher-
ing mercurial
soot. The
pipes e pass into
a large cast-
iron condenser
c, 18 inches in
jg diameter, filled
\ i‘\\\ with water to m,
\ -
a little above
the level of the
pipes: there is
Fig. 1436.
also a water valve v, by'which any danger of ex
plosion from the rising of the water into the retorts
is prevented, and the temperature is further re-
duced by placing the condenser in a large wooden
Fig. 1435. nrrnovzn DISTILLATION
FURNACE.


SIDE ELEVATION.

trough l,‘ through which cold water constantly flows.
The cylinder 0 slightly inclines towards V, so that
the condensed mercury flows along the bottom of
the cylinder, and passing down the vertical pipe v,
is collected in the iron chest 1;, which is secured by
a look at l. At the commencement of the operation,
the tube v is closed at bottom by dipping into a
shallow iron cup filled with mercury, and as the
mercury accumulates the amount of increase is indi-
cated by the graduated iron float j: The retorts are
kept constantly and uniformly ignited, so that the
injury to the joints arising from contraction and ex-
pansion by alternate cooling and heating, is avoided.
Each retort will contain a charge of ore weighing 5
cwt., and the metal is almost entirely dispelled from
it in 3 hours. -
In the year ending 5 January, 1851, the quantity
of mercury imported into the United Kingdom
amounted to 355,079lbs. In the previous year the
qucntity was 2,229,41581bs.
METAL. In the list of elementary substances
given under ATOMIC Tunonr (vol. i. p. 91), the
metals are by far the most numerous, and their im-
portance in the useful arts is equal to their extent.
They are diffused very unequally through the earth’s
crust; some are rare, others extremely abundant;
some are of most importance in the metallic state,
others when in combination with oxygen, &c. Their
properties are so numerous that we must refer to them
under their respective heads for their uses and appli-
cations, and direct our attention in the present- article
t‘o those more general properties which belong, more
or less, to all the metals, or to considerable groups of
the metals.
There are, however, certain points in which all
metals agree: they all have metallic laslre, they are
all goovl conductors of heat and electricity, and they are
all eleclro positive or calioas ,- that is, when a metallic
compound is decomposed by the electric current, the
metal is given off at the cathode, or negative pole, or
electrode.
The most striking property of metals is their laslrc,
which serves to distinguish them from the non-metallic
elements, carbon, boron, phosphorus, sulphur, sele-
nium, and iodine. This lustre is evident, whether the
metals be in masses or in small fragments, and even
when in the finest dust it can be made evident by
means of an agate burnisher. This lustre seems to
depend on the opacity of metals, and on the facility
with which they take a polish, more or less perfect :
hence they are eminently adapted to reflect light, since
their opacity prevents the transmission and their polish
the absorption of the luminous rays. There are,
however, a few exceptions to the perfect opacity of
the metals; for gold leaf transmits green rays, and
the alloy of gold and silver also, in the form of leaf,
transmits blue rays.
With respect to the colours of metals, copper and
titanium are red; bismuth is pinkish, and gold is
yellow. All the other metals present a certain degree
of uniformity, from the pure white of silver to the
bluish-grey tint of lead. '
256
METAL.
Metals differ so much in their densities, that while
potassium is lighter than water, platinum is nearly
21 times heavier than an equal bulk of that fluid.
The specific gravities of the more common metals, at
the temperature of 60°, are as follows :—
Platinum 2098 Iron . 7'79
'_ Gold ...................... .. 19-26 Molybdenum 7-40
. Tungsten ................ .. 17'60 Tin ......................... .. 7'29
Mercury 13'57 Zinc 6-86 to 7'10
* Palladium .... ..11'30 to 1180 Manganese ............. .. 6‘85
Lead 11'35 Antimony 6'70
Silver 10-47 Tellurium 6‘11
Bismuth ................. .. 9'82 Arsenic..................... 5'88
Uranium 9'00 Titanium ................ .. 5'30
_ Copper 8'89 Aluminum 2'60
Cadmium.................. 8'60 Magnesium . 1'70
' Cobalt s54 Sodium..................... 0-972
' Nickel . 8'28 Potassium............ 0-865
With respect to izardness, the metals offer differ~
ences as striking as those which relate to their
density; for while some are very hard, others can be
scratched with the thumb nail, or even moulded be-
tween the fingers. The following table shows the
relative degrees of hardness of the more common
metals :—

Titanium Hardell than Nickel Manganese .. eel. Cobalt ....... .. _
- Platinum ....\ Iron ......... .. Scggglsled by
Palladium... Antimony '
Copper Zinc Gold Scratched b
1 Silver ....... .. > Scmfched by Lead l the nail. y
; Tellurium ca 0 Span Potassium... Soft as wax.
_ Bismuth Sodium .... .. at 60“.
Cadmium Liquid at or-
Tin 1 Mercury { dinary tem-
Chromium... . peratures. 1"
- S- atcn lass.
Rhodium...) ‘u g
All the metals have the property of assuming the
crystalline form, but it is not always easy to place
them under circumstances favourable to their doing
so. Many of them occur in nature in what is called
the native state, in a crystalline form, particularly
gold, silver, copper, and bismuth. Some metals crys-
tallize when reduced to the fluid state by heat, and
allowed to cool slowly. When a solid crust has formed
on the surface, if the fluid metal be poured out from
within (as described under BISMUTH, Fig. 136), the
interior crust will be found lined with crystals. Crys-
tals of antimony, lead, and tin may be obtained in
this way, but not so readily as in the case of bismuth,
larger masses of metal and slower cooling being re-
quired. In iron foundries, crystals of that metal are
sometimes found in the midst of large masses which
have been allowed to cool slowly. Some metals are
also precipitated in a crystalline form from solutions
of their salts by means of another metal. A strip of
zinc a solution of acetate of lead precipitates the
lead in feathery crystals: silver is deposited by mer-
cury; and gold by a stick of phosphorus in an ethereal
solution; Electric currents of feeble intensity pro-
duce crystals from solutions of the metals; and it
is probable that owing to this action in the earth’s
crust many of the metals are found in a native crys-
talline form. The most common crystalline form of
metals is the regular octahedron, or the cube. Anti-
mony, however, crystallizes in‘ rhombohedrons.

Metals are often valuable in the arts on account of
their malleadz'lz'z‘y and dzzczfz'lz'ty, by‘ which they admit
of being flattened by the hammer or the rolling-mill
into leaves or plates, or drawn out into wires. The
metals, however, possess these properties very un-
equally, and some not at all; for on striking them with
a hammer they fly into fragments. Such metals are
termed brittle. The rolling'mill consists of two me-
tallic cylinders, Fig. M3 7, placed one above the other,
mounted in suitable bearings, *
with adjustments for increasing
or diminishing the distance be-
tween them. The metal to be
rolled is cast into the form of an
ingot, of nearly the same width as
the required plate: one end of the
ingot is made wedge-shaped, in
order to enter easily between the
rollers and be caught by their'grip: the ingot is then
dragged through by their motion, diminished in thick~
ness and increased in length. The operation is re-
peated many times, the rollers being gradually brought
nearer together, iuitil a sheet of almost any required
tenacity is' produced. Some metals can be rolled cold,
others require to be previously heated. During the
rolling, however, the molecular constitution of the
metal becomes modified, and its malleability dimi-
nished; it becomes hard, brittle, and difficult to work;
it is then said to be ms/z, and it requires to be
mmealed, that is, raised to a high temperature, and
allowed to cool gradually down to the temperature
at which it is worked, before the lamination can he
proceeded with. [See Annnamne] In the follow-
ing list the metals are arranged in the order of their
malleability : —-


Gold. Platinum. Palladium.
Silver. Lead. Potassium.
Copper. Zinc. Sodium. '
Tin. Iron. Frozen Mercury.
Cadmium. Nickel.
The malleability of gold is such that a grain can be
made toeover a surface of 54 square inches, and that
leaf~gold is mth of an inch in thickness. [See
GoLn]
The dzzczfz'lz'zfy of metals does not follow the order of
their malleability ; as for example :—
Gold. Nickel. Lead
Silver. Copper. Palladium.
Platinum. Zinc. Cadmium.
Iron. Tin.
The ductility of metals depends upon their Zelzacz'iy,
or power of resisting the tension applied to them in
forcing them through the holes of a
draw-plate, which is an oblong piece of
steel, Fig. with trumpet—shaped
holes gradually. diminishing in size.
The metal/is first formed into a rod;
the extremity is then pointed and
dragged through the-"largest hole;-
then” through the next smaller . size, F59‘ 1438'
ands‘??? on gradually decreasing’ in diameter; but be-
tween these. operations the metal requires to be
amiealed as in the case of the rolling-mill. By


Gfifimw
METAL.
957
this means silver can be drawn into wires 155th
of an inch in diameter, and by enveloping an ingot
of gold with silver previous to drawing, a grain
of gold may be drawn into a wire 550 feet long : this
wire is covered with silver, which may be washed Ofie
by putting it into dilute nitric acid, and the resulting
gold wire is only E-b-lfith inch in diameter. Platinum
' has been substituted for gold; and a wire not exceed-
afiwth inch in diameter has been produced. Very
fine steel wires have been formed by first enveloping
‘mm—- the steel in silver, and, after the drawing,
dissolving off the silver by means of
mercury. [See Wrnn-nnxwrnej
The tenacity of metals is the power which
they possess of resisting tension without
breaking. It varies with difl'erent metals,
and a comparative estimate may be formed
by suspending from a fixed point different
wires of equal length and diameter by one
extremity, and attaching a scale-pan to the
other extremity, as shown in Fig. 1439.
Weights are successively and carefully
added to the scale-pan until the wire breaks,
Fi9-1439- and the number of pounds, 850. represents
its tenacity as compared with other wires tested under
similar circumstances. The following weights were
sustained by wires 0'7 87 of a line in diameter :—
549'250 lbs. Gold 150-753 lbs.


Iron...............
Copper 302-278 ,, Zinc ........... .. 109'540 ,,
Platinum 274'320 ,, Tin 34-630 ,,
Silver 18713? ,, Lead 27'621 ,,
The tenacity of metals varies greatly in the same
metal with its purity and the method by which it has
been wrought. The tenacity is much diminished by
the process of annealing. A wire of soft iron which
sustained a weight of 261bs. only sustained 12 lbs.
after being annealed; and one of copper, which sus-
tained 22lbs. before annealing, was broken by Qlbs.
after being annealed. In fact, the process of anneal-
ing had removed the particles to a greater distance
from each other, than the rolling-mill or the draw-
plate had condensed them.
The following metals are brittle: most of them
may be reduced to powder :—- '
Antimony. Cobalt. Titanium.
Arsenic. Columbium. Tungsten.
Bismuth. Manganese. Uranium.
Cerium. Molybdenum. Rhodium.
Chromium. Tellurium.
Metals vary greatly in their coizclactiizg powers for
heat, as shown by the following table, the numbers
representing merely an approximative ratio :---
Gold 200 Zinc 73
Silver............. 195 Tin 64
Copper............ 180 Lead 36
Iron 75
Those metals which transmit heat with the greatest
facility are best adapted to the manufacture of steam-
boilers, stove-pipes, and other forms of apparatus
where it is of importance for the heated surfaces to
part with their heat quickly to surrounding bodies.
Metals vary greatly in their capacity for heat, or
their specific Izeat : that is, the amount of heat re-
quired to raise equal weights of the different metals
to the same temperature. If the quantity of heat
VOL. II.

required to raise 1 lb. of water from 32° to 212° be
expressed by 1000, the amount of heat required to
raise 11b. weight of each of the following metals is
expressed by the decimal numbers opposite to each :-—
Gold ................ .. 0'0324 Tin .. .. 0 0560
Silver................. 00570 Zinc 0'0929
Platinum 0'0324 Cadmium............ 0'0567
Palladium ........ .. 0'0593 Antimony 0'0508
Iridium 0'0368 Bismuth 0'0270
Mercury 0'0318 Arsenic............... 0'0814
Copper ............. .. 0'0950 Manganese ....... .. 01441
Nickel 0'1086 Uranium 0'0619
Cobalt................ 0‘1172 Molybdenum .... .. 0065!)
Iron .. 0'1132 Tungsten............ 0'0364
Lead 0'0320
The linear eapaiisicrz of a few of the metals on being
raised from 32° to 212° has them thus stated :—
Gold 0'00155155 = Fla-st.
Silver 0-00190868 = 51th.
Platinum 0'00099180 = fi-lfith.
Palladium 0-00100000 = ,Joorh.
Copper 0‘00171733 = g-gqd.
0'00123504 = Fli—Eth.
Lead . 0'00284836 = s-Jfist.
Tin (from Malacca) 0‘00193765 = T57th.
Zinc (Cast) 000294167 = 5101211.
Zinc (Hammered) 0'00310833 = 3%,
Bismuth........................... 0'00139167 = figth.
Antimony . 0'00108333 = g-g-id.
Fasicility. All the metals admit of being fused by
the application of heat, but the temperatures at which
they liquify are very various. At higher temperatures
than are required for fusion the metals are volatile,
and many of them maybe distilled in close vessels.
Some metals acquire a pwasty or adhesive state before
becoming fluid: such is the case with iron and plati-
num, and also with the metals of the alkalies. In con—



sequence of this valuable property pieces of iron and
steel can be united without solder by the process of
welding, and the finely divided metallic sponge of
platinum converted into a solid and compact bar.
In the following table, the metals are arranged in the
order of their fusibility :—
Fahr.
{Mercury — 39°
5 Potassium + 136
.51 Sodium 190
'8 Tin 442
i; Cadmium 450
g n Bismuth............................... 497
'76 Lead 612
'3 'Tellurium is rather less fusible than lead.
:é' Arsenic volatilizes before it fuses.
H \ Antimony fuses a little below redness.
(Silver 1873
Copper 1996
Gold 2016
Cobalt is rather less fusible than iron.
Iron, cast 2786
‘5', Iron, malleable Require the highest heat of a
3 Manganese smith’s forge.
'3 .Nickel, nearly the same as cobalt.
2 Palladium ....... ..
5 Molybdenum E Uranium ........ ..
.2 Almost infusible, and not to be
a , _ """ " procured in buttons by the heat
é Tltzfmum """" " of a smith’s forge; but fusible
Q Cenlfm """"" " before the oxyhydrogen blow-
Osmium pipe.
Iridium
Rhodium ....... ..
Platinum ....... ..
\Columbium .... ..
258
METAL.
Many of the metals (copper, iron, and tin, more
especially) ifv slightly elevated in temperature-by fric-
tion, or otherwise, emit a remarkable ocloar, and if
applied to the tongue impart a metallic taste.
The harder metals are elastic and soaoro'as, but
these properties are more conspicuous in some of the
alloys than in the pure metals.
Metals form certain combinations with each. other
which are termed alloys [see ALLOY], or if mercury be
one of the combining metals, amalgams [see AMALGAM].
Infthese'cases ‘the distinctive characters of metals are
retained‘; but in the ‘compounds formed by the union
of‘ a metal with the ~non~metallic elements, form-ing
what are called oa'i'cles, chlorides, salpla'cles, &c., the
metallic character most frequently disappears.
The affinities of the different metals for oxygen
vary greatly. Some of the metals combine with it at
all temperatures, and are reduced with difficulty;
others, on the contrary, cannot be made to combine
directly with it, and their oxides are decomposed at
a slight increase of temperature. These different
affinities of the metals for oxygen may be estimated
in various ways. 1. By their behaviour with oxygen
gas or common air at different temperatures. 2. By
the greater or less facility with which their oxides
are reduced to the metallic state. 3. By their power
of decomposing vwater under varying circumstances.
4:. By their power of decomposing water acidula'ted
by one of the stronger acidsa as when water is acidu-
lated by sulphuric acid, iron or zinc decompose it at
ordinary temperatures with the evolution of hydrogen
gas. [See HYDROGEN] Other metals do not produce
this effect even at high temperatures. The decom-
position, however, is influenced by the affinity of the
resulting oxide for the acid, and also by the degree of
solubility of the salt produced.
According to these views Regnault1 arranges
the metals into six groups, which show at a glance
their most strikingv characteristics. In the first group
are those metals which absorb oxygen at all tem-
peratures, even the most elevated, and of decomposing
water at the lowest, hydrogen gas being‘ abundantly
evolved. These metals are;- ' I’ i i Lithium.
Barium.
Strontium.
Calcium.
Potassium.
Sodium.
The first three are called allsalz'ae metals: the last‘
three are the metallic radicals of the a-l/ea-lz'ne earths. -
In the seooacl group are placed those metals which
absorb oxygen at the highest ‘temperatures, and" whose
oxides are not reduced by heat alone: these metals
do not sensibly decompose water at low tempera,
tures, but they do so decidedly above 122°.. They
are—-
Manganese. . .Magnesium. Aluminum.
To which the following may also probab_lybe,added—-
, p j V p I I
. ~ ; pertl'e‘s. . The strong bases are all protoxides, contain-
‘ ing'i‘singleI-equivalents ‘of metal - and ‘oxygen: the
i Weaker-'ebasés‘ "fife usually vses'quioxides, "containing'2
Glucinum. Thorium. .Didymium; f eiuiegiiltiumvu "1 ' Erbium.
.vuirjzjg 1 "- TefbiunL'
The Cemrrehends'l nsamaiaam- 1
posei‘vvatei‘ii’at'ita "'fe‘clihéatgvrhosfe oxides are not re-

(1) Cours de Chimie, tome 2e.

duced by heat alone, and which do not decompose
water below 212°; but they all decompose water at
ordinary temperatures when acidulated by the stronger
acids. They" are——
Iron. Chromium. Cadmium.
'Nick'el. Vanadium. Uranium.
Cobalt. Zinc.
The temperature at which these metals decompose‘
water and absorb oxygen depends greatly upon their
state .of division. Iron, in the state of filings, does
not ‘absorb oxygen rapidly at ordinary temperatures;
if heated to dull redness in oxygen gas the action is
so rapid as to produce heat and light : 'if‘the metal be
very minutely divided, it will take fire by mere expo-
sure to the air. [See Inon] Iron filings decompose
steam at 450°. '
In the foart/z group are those metals which absorb
oxygen at a red-heat, and hence cannot be reduced to
the metallic state by heat alone ; they decompose
steam with great facility, but not water acidulated
by the stronger acids. The reason is that the oxides
of thesemetals afford but feeble'bases, while most of.
them, in the presence of the stronger bases, such as
potash and soda, behave as acids. Thus most of the
following metals decompose water in the presence
of the alkalies with the production of hydrogen gas:—
Tungsten. Tantalum. Tin.
Molybdenum. Titanium. Antimony.
Osmium.
And probably,
Niobium. Ilmenium. Pelopium.
In the fifth group are metals whichabsorb oxygen
at a red-heat, and whose oxides are not reducible by
heat alone: they decompose Water at very high tem-
peratures, but only in a feeble manner: they do not
decomposev water in the presence of acids or alkalies.
They are—- ‘
Lead.
Copper. . Bismuth.
In the stat/t group are metals whose oxides are
reducible by heat alone. They are-—
Mercury. Iridium. . Ruthenium.
Silver. Palladium. Gold.
Rhodium. Platinum.
All the metals whose oxides are. not decomposed
by heat alone can decompose water at temperatures '
more or less elevated. This arises from the fact that
water is resolved into its elements at very high tern-
perature's, and ‘when an oxidisable metal is present,
the latter ‘unites with the oxygen‘to ‘form an oxide,
and thehydrogen escapes in the gaseous form.
The metallic oxidesifvary greatly in their properties.
Some of possess basic characters .more or less
1 marked’; others will not combine. either with acids or
with'alkali‘es 50whi1e~ a'third set ‘have distinct acid pro-
equivalents‘joif‘inetal,Lfand '3 of‘ oxygen» : the‘ peroxides‘,
or neutralrcompounds; contain still moreoxygen; {and
lastly ."1 lillé"'m'ét_éilli§?'aeids contain theelarges't“quantity
a of 'OXy‘géIiif' The gradual change in’prcp‘erties byth'e
METAL. 5159
increasing proportions of oxygen may be illustrated
by taking manganese as an example :---
Metal. Oxygen. Symbols. Characters.
Protoxide 1 eq. 1 eq. MnO. Strongly basic.
Deutoxide 2 eq. 3 eq. Mn203. Feebly basic.
Peroxide.................. 1 eq. 2 eq. Mn0,,. Neutral.
Manganic acid ....... .. 1 eq. 3 eq. Mn08. Strongly acid.
Hyperrnanganic acid. 2 eq. 7 eq. M11207. Strongly acid.
A powerful oxygen acid and a powerful metallic
base uniting in such proportions as exactly to neu-
tralize each other’s properties, form what is called a
aoazfml salt‘; it produces no efl’ect on litmus or
turmeric paper. In neutral salts there is a constant
relation between the quantity of oxygen in the base
and the quantity of acid in the salt, which is thus
expressed :——-To form a neutral combination, as many
equivalents of acid must be present in the salt as
there are of oxygen in the base. Mr. Fownes thus
explains the application of this law :-—“ When a base
is a protoxide, a single equivalent of acid suitices to
neutralize it; when a sesquioxide, not less than three
are required. Hence, if by any chance the base of a
salt should pass by oxidation from the one state to the
other, the acid will be insutficient in quantity by one
half to form a neutral combination. Protosulphate
of iron. offers an example: when a solution of this
substance is exposed to the air, it absorbs oxygen,
and a yellow insoluble sad-salt‘ is produced, which
contains an excess of base. 41 equivalents of the
green compound absorb from the air 2 equivalents of
oxygen, and give rise to 1 equivalent neutral and 1
equivalent basic persulphate, as indicated by the dia-
gonal zig-zag line of division :—
1 eq. iron + 1 eq. oxygen 1 eq. sulphuric acid.
1 eq. iron + 1 eq. oxygen 1 eq. sulphuric acid.
+ 1 eq. oxygen from the air.
1 eq. iron + 1 eq. oxygen .................. Hal eq. sulphuric acid.
1 eq. iron + 1 eq. oxygen 1 eq. sulphuric acid.
+ 1 eq. oxygen from the air.

Such subsalts are very frequently insoluble.”
Chlorine, iodine, bromine, and fluorine, combine
with the metals and form compounds, which possess
a highly saline character. But if a salt be a com-
pound of an acid and a base, the chlorides, iodides,
&c. are certainly not salts, and even common table-
salt (chloride of sodium, or, as it was formerly termed,
' muriate of soda), which gives the name to the nume-
rous family of salts, has no relationship therewith.
To get rid of the difliculty of excluding bodies which
partake so largely of the saline character, ‘if not in
constitution, at least in properties, two classes of salts
have been formed; the first, named lzaloz'd salts (from
57m, sea-salt, and 6280;, form), includes those consti-
tuted after the type of common salt, containing a metal
and a salt-radical, as chlorine, iodine, &c.; and the
second, named oxygen-acid, or arty-salts, includes
those salts which are generally represented as being
composed of an acid and an oxide, such as sulphate
of soda, nitrate of potash, &c.
The old term, muriate of soda, was applied to culinary
salt on the supposition that muriatic acid combined
with soda to form such a salt; but according to the
more modern and probably correct view, when a solu-

tion of a hydrogen acid, such as muriatic, now called
lzydroolzloa'z'o acid, is poured upon a metallic oxide,
both are decomposed, and water and a haloid salt of
the metal produced. In the case of hydrochloric acid
and soda for example :—
Hydrochloric Chlorine .... .. Chloride of Sodium.
acid Hydrogen \
Soda Sodium "" " /
Oxygen .... .. Water.
On evaporating the solution crystals of chloride of
sodium are obtained.
The properties of the two great classes of salts are,
however, so very similar that attempts have been
made to constitute them alike. Thus we may regard
oxy-salts not as compounds of an oxide and an acid,
but as containing a metal in union with a compound
salt radical having the chemical relations of chlorine
and iodine. Thus sulphate and nitrate of potash will
be constituted in the same manner as chloride or
sodium, the compound radical replacing the simple
one. Hence, instead of representing sulphate of pot-
ash by KO—]- 803 it will be K+SO,, and nitrate of
potash instead of being KO+NO5 will be K+NOG.
Hydrated sulphuric acid will be, like hydrochloric acid,
a hydruret of salt-radical 11+ 804. 1When the latter
acts upon metallic zinc, the hydrogen is simply dis-
placed and the metal substituted, no decomposition
of water being supposed to take place. When the
acid is poured upon a metallic oxide the same reaction
occurs as in the case of hydrochloric acid, water and
a haloid salt are produced. All acids are therefore
hydrogen acids, and all salts haloid salts, with either
simple or compound radicals. This binary l/zeory of
salts, as it. is called, was originally suggested by Sir
H. Davy.
Sulphur combines with all the metals leading to the
production of salp/zarels or salp/a'des. Many of them
have a saline character, and are soluble in water,
such as the sulphuret of potassium and of sodium.
Two sulphurets will in some cases unite in definite
proportions and form a crystallizable compound. Such
bodies resemble oxygen-acid salts; “they usually
contain a nionosulphuret of an alkaline metal, and a
higher sulphuret of a non-metallic substance, or of a
metal which has little tendency to form a basic ends,
the two sulphurets having exactly the same relation
to each other as the oxide and acid ‘of an ordinary
salt. Hence the expressions salp/tar salt, gulp/tar acid,
and’salpfiar oase ,- they contain sulphur in the place
of oxygen. Thus bisulphuret of carbon is a sulphur
acid : it forms a crystallizable compound with simple
sulphuret of potassium, which is a sulphur base.
Were oxygen substituted for the sulphur in this pro-
duct we should have carbonate of potash. KS+GS2
is the sulphur salt, and KO+002 the oxygen salt.”
Two different bases are sometimes united with the
same acid, forming what are called doable salts. Thus
sulphate of copper and sulphate of potash mixed in
the ratio of their equivalents, dissolved in water and
evaporated, a double salt, viz. sulphate of potash and
copper, is obtained. Those salts called sajior or acid
salts, such as bisulphate of potash, which have a sour
taste, and an acid reaction to test paper, are by some
5 2
20f)
METALLURGY.
chemists regarded as double salts, in which one of
the bases is water. “ Strange as it may at first sight
appear,” says Fownes, “ water possesses considerable
basic powers, although it is unable to mask acid reac-
tion on vegetable colours; hydrogen, in fact, very
much resembles a metal in its chemical relations.
Bisulphate of potash will, therefore, be a double
sulphate of potash and Water, while oil of vitriol must'
be assimilated to neutral sulphate of potash. KO-l— $03
and HO—l—SOs.” Water is a weak base : it is for the
most part easily'displaced by a metallic oxide, but
occasionally it decomposes a salt in virtue of its basic
power. A few acid salts contain no water: bi-
chromate of potash for ‘example. Such a salt may be
constituted with 2 equivalents of acid to 1 of base.
For further remarks on the constitution of salts we
must refer to CRYSTALLIZATION, and a few other
articles. The principal metallic salts are noticed
under the names of the metals as they are separately
treated of. .
METALLURGY is the art of extracting metals
from their ores: it depends on certain mechanical
and chemical operations, the object of the former
being to separate much bulky worthless material, in
order that the chemical processes’ may be performed
with advantage on the residual metallic portion. By
the mechanical processes, the mineral is separated
v'\ \\i
"s
" ‘1|
p
\ \a. - ' ' p
N \\ \
~\ \% - \ \
rib-s;
A- . . ,_~ _
._ 51", ) , H3,‘- \-
_ . a. - ,u_._ 5:’- -'
_ .r'a “ “#4? it’: ',' _-I.,_ .
. “,_-\_r/_~ . i_-_.fjf.,1~:v : ‘If. .;
‘h . :1‘ . , ..
ass“ “as. \‘Iimmz'm
g." '~" -' \ 'fi-G-a ,
_ /
-. J _ I I
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~~~~ ~ '




— ‘ ~.7;- i --, -C .,_ ,..
4-’ ‘ --. --l~..\;;s"\"==f;:r¢a:~-.,- 7' -
I-‘ig. 1440. BREAKlNG AND son'rrnc corren ones.
from its gangue (quartz, felspar, limestone, barytes,
&c.), and by the chemical, the metal is smelted 01' dis-
entangled from its mineralizer (sulphur, arsenic, phos-
phorus, 850.) A special chemical treatment is‘, in
general, required for each metal, and will be found
described each‘ under its own heading‘. The mechani-
cal processes are of a more general nature; but their
extent must‘depend, in great measure, upon the com—
mercial value of the metal, and the facility with which
its ores can be dressed and afterwards smelted. The
ores of iron would not repay the cost of mechanical
preparation, in consequence of their abundance, the




Iv‘; . ~ - -

ease with which they are reduced, and the consequent
low price of the metal. The ores of copper admit of
a good deal of preparatory dressing, on account of
the higher commercial value of that metal.
‘The first dressing of the ores is usually performed
by the miner: he separates the larger fragments of
the gangue, and sends up only such a description of
ore as will. pay the,cost of the labour to be bestowed
upon it. On reaching the surface the ores are sorted
by women and ‘children, and broken up by means of
hammers ‘into, 1, fragments rich enough to be sent at
once to the 'caleiner or to the smelter; 2, into pieces
composed of the mineral mixed with the gangue, and
which require dressing; 3, ‘into fragments of the
gangue, which are rejected. ,The'fragments in the
second class are crushed by meansof large cylinders
of cast-iron, and after passing “between these, the
crushed mineral falls into the ' upper extremity of
an inclined cylinder of coarse wire gauze, which,
moving upon its axis, separates the pulverised mineral
into two classes: the one passing through the meshes
falls on the floor; the other, consisting of fragments
too large to pass through, falls out at the lower ex—
tremity of the cylinder into an endless chain of
buckets, by which it is raised to the level of the mill
to be crushed over again. Ores of copper are treated
in this way. The ems/ring WNW/{1:726 used at Alston
Moor for breaking
the mingled ores of
lead is represented
in the steel engrav-
ing. ' It consists of
one pair of fluted
cylinders ff’, and
2 pairs of smooth
cylinders c 0, which
are all used for
crushing the ore.
They are turned in
opposite directions
by means of toothed
wheels 5 1," 2!”, work-
ing into each other,
and fixed to the
shafts. of one of
each of the 3 pairs
of cylinders. Mo-
tion is given by a
water-wheel 20 w, to
_ the axis of which is
attached one of the fluted cylinders f’. The axis
of the water-wheel also carries a cast-iron toothed
wheel 2f, geered with the toothed wheels 2," 2”, fixed
upon the ends of: two of the smooth cylinders.
Above ‘the fluted. cylinders‘ is a hopper H, which
discharges between them the ore, as it is brought by
the waggons W.‘ These waggons advance upon a
railway, and as each gets over the hopper, its motion
is arrested, and a trap-hole opening outward in the
middle of the bottom is let fall, and the Waggon dis-
charges its contents into the hopper. Below the
hopper is a’ small bucket called a shoe, into which the
5:
=1
'-
v- 4:
- ll "
"- iii-‘RT.-
~ .:,_L:---;3_=_-_§,:; - ..





Milli Tfitlhllillllt‘lkiiiilnnu litllllblb if‘ loilfn


METALLURGY.
261
ore is shaken down, and which throws it constantly
upon the cylinders in consequence of a jolting motion
given to it by a crank rod t, Fig. 2, attached to
it, and kept vibrating by the teeth of the wheel r.
The shoe is regulated in such a manner as to prevent
too much ore falling on the cylinders and obstructing
their motion. A small stream of water is also let into
the shoe for the purpose of preventing the cylinders
from heating. The ore is first passed between the
fluted rollers, then falls upon the inclined planes 2' i,
which turn it over to one or other of the pairs of
smooth rolls.
chine: they are made of iron, and the smooth rolls
are case-hardened, or chilled. [See OASE-I-IARDENING
—-—- ANNEALING.] The gudgeons of the cylinders
move in brass bushes (t, Fig. 3) fixed upon iron
supports, 1, made fast by bolts to the massive wood-
work supports of the machine.
Each of the horizontal bars has an oblong slot, at
one end of which is solidly fixed one of the plummer
blocks, or bearers of one of the cylinders o’, and in the
rest of the slot the plummer block of the other cylin-
der 0 slides. This construction permits the 2 cylin-
ders to approach each other so as to be in contact, or
to recede from each other as circumstances may re-
quire. The movable cylinder is driven up nearer to
the fixed one by means of iron levers LL, which carry
at their ends the weights 20, and rest upon wedges and‘,
which can be made to slide on inclined planes p p.
In such cases these wedges press upon the iron bar
'0, Figs. 1 and 3, and urge it nearer the movable
cylinder by advancing the plummer block which sup-
ports its axis. The effect of this arrangement is, that
if a very large and hard piece of ore get between a
pair of cylinders, one of them would yield and allow
the piece to pass without injuring the mechanism.
This object may be attained by a more compact
arrangement, as shown in Fig. 4!. The bearings s s’
of the rollers 00 slide in grooves, and the shoulder ll
of the loaded lever L, pressing up against the bearing
.9’ constantly tends to keep the surfaces of the two
cylinders in contact : the weight W is adjusted so as
to suit the hardness of the mineral to be broken. In
addition to the 3 pairs of rollers of which each crush-
ing machine consists, a fourth pair is sometimes
added for crushing the moderately rich and poorer
pieces of lead ore known as c/zals and calling/s, pro-
duced by the first sifting of the brake sieve. These
cylinders are smooth, and are known as o-lzals-rollors.
One of them is usually placed on the prolongation
of the shaft of the water-wheel on the side opposite
to the principal machine, and the other, which is
placed alongside, receives its motion from the first
by toothed wheel-work. When the gangue is too
hard to yield to the rollers, and for those ores which
require to be ground more finely than is done by
rolling, a stamp-mill is used.
Many minerals, such as tin, are pounded into small
fragments by means of large pestles, in an arrange-
ment called a damping-mill, which will be described
presently. The ores are then concentrated by a variety
of operations similar in principle, but varying greatly
These are the chief parts of the ma--

in detail. This principle ought to be clearly under-
stood before the operations themselves are described,
and as it has been very clearly explained by ltegnault,
in the third volume of his “ Oours de Chimic,” we
give an abstract of it in this place :—-
If bodies differing in form, magnitude, and density
be allowed to fall from a considerable height into a
tranquil liquid, they will evidently experience dif-
ferent degrees of resistance in finding their way to the
bottom, so that they will not all reach it at the same
time; but will arrange themselves in a certain order,
which it is of importance to the metallurgist to be
able to determine. If these bodies have the same form
and dimensions, and differ only in density, it follows,
since the resistance which a body experiences in
moving through a liquid depends on its form and the
extent of its surfaces, and not upon its density, that
all these bodies will lose an equal amount of moving
force in passing through the liquid. But this loss
will be most felt by bodies which have a less degree
of velocity, such as bodies of less specific gravity.
They will fall more slowly through- the liquid than the
denser bodies, and arriving last of all. at the end of
their course, will be found resting on the denser
bodies in a graduated order, the most dense being at
the bottom, the least dense at the top of the solid
strata.
If the bodies which fall through the liquid are of
similar density and form, spheres or cubes, for example,
but of varying magnitudes, their velocity will. be in
proportion to their size, and the largest fragments will
form the lowest stratum at the bottom of the vessel.
The bodies being alike in density and form, the resist-
ance in falling through the liquid is proportional to
the surface exposed; and as the volumes of bodies
vary according to the cube of their corresponding
dimensions, while the surfaces only vary with the
square, it follows that the velocity of descent which
animates them is regulated by their cubes, d3, while
their resistance is-in proportion to their squares d?- :
hence the descending force of- a body increases much
more rapidly than the resistance offered'by its surfaces.
If, lastly, we suppose all the bodies to have the
same volume and density, but to vary in form, some
being cubical and others in the form of flat rectangu-
lar laminae, or scales ; the latter. having a'mueh greater
extent of surface than the cubes, experience a much
greater amount of resistance in- falling through the
liquid: the cubes will arrive first at the bottom, and
upon them will be deposited the plates or scales, and
if these are more orrless flattened, the flattest will
occupy the-highest stratum. '
New, to apply these principles to the dressing of
ores. We have seen that the ores are first broken
up and separated. into distinct classes, each of which
comprises fragments of about the same size. us
suppose that these fragments consist, some of pure
mineral, some of gangne only, others of mineral and
gangue mixed, but that all have the same form and
the same volume. As the metalliferous part is usually
much denser than the gangue, it is evident that in
falling through water from a considerable height, the
262
METALLURGYY.
densities.
mineral would arrive first at the bottom, and would
be followed by fragments composed of mineral and
gangue, and the pieces of pure gangue would arrive
last. The mixture would thus be formed into three
portions; gangue at the top, which could be ‘sepa—
rated and v‘throw-n away; pure mineral at the bottom,
which could also ~ be separated, and sent to the cal-
ciner or to.‘ the smelter; while the intermediate portion
would have to be again crushed, sifted, ‘&c. to get rid
of more of the ‘gangue. Hence it, will be seen how
important? a it is that- the fragments of the ore which
are to berconce'ntrated by washing, should be nearly
of‘ the ' same size and form. This, however, is
'not'always possible.‘ It is "comparatively easy to
reduce the fragments to the ‘same size, but their forms
must; to a great ‘ extent, depend on the molecular
constitution of the mineral and gangue, and on their
natural cleavages, &c. Hence it is very likely that
among the crushed fragments of an ore, all of which
have passed through the same riddle, there may be
found lamellar pieces of the metallic mineral, and
cubical or spherical pieces of the gangue. The mine-
ral, by its superior density, would tend to pass more
quickly through the water than the gangue; but the '
latter, ‘in consequence of its form, may experience less
resistance than the lamellar fragments of the metal-
lic compound; and hence the two bodies may arrange
themselves according to the inverse order of their
Cases of. this kind constantly occur in
practice, and hence the results are not so precise as
they would otherwise be if the conditions upon which.
the-theoryis based could be realized. Of course, the
more nearly these conditions can be realized, the more
-'perfe,ct-will be the purification of the ore by washing.
As tolerably complete illustration of the mecha-
nicalrpreparationof ores, we‘will give a full abstract
of Mr. Henwood’s valuable paper on the methods
adopted in. Cornwall ' for dressing tin ores.1 It may,
however, be necessary first to state, that tin ores
are generally carried through all the operations
necessary for their purification previous to being
smeltedfl The smelter ,has,;thf.erefore, only to carry'
them twice through the furnace: by the first melting
they are brought into a metallic state; and by the
second, the metal is sufficiently purified. The ores
of: copper, on the contrary, are only brought by the
miner into the state which makes them fit for roasting
or calcining: in this state they are sold to the
smelter, who passes them through the long series of
operations described under Oorrnn, before the metal
fit for .the market. On this account, although a
given quantity of average copper ore, as it comes
,fromthelode, is much richer and more valuable than

amequal quantity of tin ore in the same state, the
ore,-when;prepared for sale, is at least seven times
richersthan-thatcf the copper. '
‘(newspaper is printed among the “ Transactions of the Royal
Géological'Soei‘ety of Cornwall.” The engravings are from original
drawings made .ongthaspot'by Mr; F. B. Miller, of King’s College,
Londpmyfor. ,thepurpose. of illustratingatreatise in the Editor’s
work'on the Useful Arts, 8:0. published under the sanction of the,
Committee of General Literature and Education‘appoin'ted by the
Society fonP-romoting Christian Knowledge. '

_ The "tin of the Cornish mines is nearly'all‘inv the
‘ state of peroxide, of variable purity; it is sometimes
crystalline, and at others mingled with much earthy
matter. When raised from the mine, the first opera-
tion is to break in pieces, about as large as a m‘an’s
fist, any pieces of ore, or stones as they are called,
that may exceed that size, and to reject such portions
as do not contain more'ore than will repay the cost
of dressing. In some stones the tin ore is scarcely
perceptible to the eye; in which case the workman
from time to time reduces a small quantity to a fine
powder, and by repeatedly immersing it in water, and
shaking it to and fro on a‘ shovel, the impurities are
removed‘: by this simple operation, which is called
naming, the quality of the. ore is roughly ascertained,
as well as the size to which it must be reduced in
order to free it from foreign substances.
The ore is now ready for ‘the steaming-mill. This
consists of a number ‘of upright wooden beams called
stampers, about ten feet long and eight inches square,
to the lower extremities of which are attached pieces
of cast iron, varying in weight from one hundred and
a-half to four hundredweight and a-quarter. These
are placed in a wooden frame, and alternately lifted
up about ten inches by the cogs or wipers of a hori-
zontal axle, which is moved round either by a water-
wheel or a steam-engine. [See 1) d of the steel
engraving] Where the latter power is used, the
number of stampers is increased to 2d, 36, and even
418. The ore is placed on an inclined plane close to
the bottom of the Stampers, and as these are lifted
up, a portion of it slides down directly beneath them
and is crushed by their fall. The aperture through
which it is admitted, is of ‘such a size as to prevent
the entrance of so much as would impede the action
of the machine. The second stamper is lifted an‘
instant before the fall of the first, and the third before
that of the second. The fall of the first forces a
portion of the ore beneath the second, and that of
the second beneath the third: the fall of the last
forces such of the ore as has been sufliciently pul-
verised through a copper ‘or iron grating, placed
opposite the aperture by which the ore is admitted
under the stamper. The holes of the grating vary
in size according to the nature of the ore, from the
diameter of a reed to that of a small needle. The
whole arrangement is copiously supplied with water,
which assists the progress of the tin through the
grating. Adjoining the stamping-mill, and connected
with the grating by a conduit, are two pits : the ore
after passing through the grating runs into the nearest
pit, in which the rough ore lodges, as well as the
heavier part ~:ot' that which has' been reduced to
powder, and knownrby the name of ‘slime ,- this rough
ore whendressed is- called the crop. The remainder,
with thev light-er sliine,-which, passing through the
first pit, is retained in the second, when dressed, is
called the-'Zeavinga'aand.ivaries in quantity ' from one.-
fourth to 'one-seventhvof the whole. Now begins the
process of purification, so ‘far as to prepare the ore
for being smelted; andrthis comprises a large number 1 -
and variety of operations,"but the great principle of ‘
METALLURGY.
263
the whole is that of subsidence by the superior weight
of the metallic portion, as compared with the stony
and earthy matters which are to be got rid of.
The first operation on the crop is called bazlclliay.
The buddle is a wooden case about 8 feet long, 3
wide, and 2%,— feet deep, fixed in the ground, one end
being a little elevated ; on the rim of the higher end
is fixed a board, called the ‘frigging-board, from 12 to
16 inches Wide, extending from side to side, and
somewhat more inclined than the huddle. The opera-

Fig. 1441.
DUDDLING.
tor, who may be a man or a woman, spreads the ore
on the jagging-board, and with a shovel cuts it into
small furrows parallel to the length of the buddle:
a small current of water, which is admitted at the
head of the buddle, is made to flow equally on
every part of the board. The quantity of water is
regulated by the roughness of the ore; the coarsest
requires about as much as a circular aperture,
1% inch in diameter, would admit; but the finest
only about one-ninth of that quantity. The action
of the water carries all the ore into the case, where
the richer and finer portions subside near the
head, while the rougher and lighter portions are
carried towards the lower part. The workman, who
stands in the buddle, or on a plank over it, about 3
feet from the head, assists the action by gently
passing the foot, or a tool held in the hand, along
from side to side. When the ore is rough, this
operation is sometimes performed with the naked
foot; but when the particles are very fine, the foot
is usually shed with a smooth piece of wood called
the brogae. This process is continued until the huddle
is full. Its contents are then divided into three or
four parts, according to the quality of the ore; the
richest part, termed Izcarls, is near the head of the
huddle; the tails, or worst part, being near the foot;
the intermediate portions are called first and second
mirlcllc Izcacls. These are again scpaately huddled,
until the ore at the head is freed from the poorer
and rough particles. The leads are then tossed or

toeecl in a kieve or large tub, about one-third filled
with water, which one workman stirs about rapidly
while another gently puts in the ore with a shovel.
The tub is furnished with a stirrer, the construc-
tion of which will be seen in Figs. 1.442, 14.413.
The stirring is continued till the vessel is nearly


" ‘a’. 1...? .
‘ ill 1
‘l'lh ..\
l
Jill ll)‘
l
l
i
Fig. 1442.
‘DOS-SING, OR. TOZING.
full: it is then stopped, and the outside of the
kieve is struck smartly with a hammer until the
ore has subsided: this is called [vac/sing. By this
process the most impure parts are brought to the top,
whilst the remainder sub-
sides in the order of its
weight.v The whole is now
divided horizontally into
two or more parts, the
lowest division being fit
for smelting, unless it is
found to require roasting,
in order to‘get rid of the
ores of iron, copper, and
zinc, which is often the
case. The upper division,
called skimpiags (skimmings), are again huddled and
tossed; the tails are thrown amongst‘the leanings,
and the ore in the lowest part of the kieve is again
fit for the smelting or the calcining-house.
The first middle heads are also subjected to an
operation termed c/iimmiag, which is similar to tossing.
The kieve in which it is performed is inclined at an
angle of about 46°. About 2cwt. of ore, with an
equal weight of water, are put into it, and violently
agitated by stirring until the whole of the ore is
suspended: the vessel is then beaten on the outside
as in tossing; the water being withdrawn, the upper
layers of ore, also called skimpings, are treated in
the same way as after tossing: the lower part is fit
for the smelting or calcining-house. This plan may
be substituted for tossing both for heads and middle
heads, especially when the impure parts of the ore
are very heavy. When the kieve is inclined, the space
at the bottom is narrower, while the space near the
surface of the water is larger and the depth greater
than if it were horizontal, as in tossing. Mr. Henwood
thinks it probable that the impure parts are thus
more easily kept in suspension, and from the greater
vibrating motion imparted by the hammering, in con-
sequence of the kieve resting on a small and narrow


Fig. 1443. THE KIEVE.
26%
METALLURGY.
base, the whole of the richest part may subside more
speedily than it does in tossing.
The second middle heads are generally subjected to
the operation of diilning. It is performed with a
hair-bottomed ~ sieve of close texture, into which an
assistant puts about 30 pounds of ore: the operator
then immerses it in a kieve about two-thirds full of
water, and by moving it round, as well as up and
down, and from side to side in the water, the small
and light particles become suspended, and by inclining
the sieve, they pass out of it andsubside at the
bottom of the kieve':1 the sieve is regularly replenished
from the ore-heap by the assistant, and the operation
is continued. Whether the. ore in the sieve is now
fit for the smelting-housais ascertained by the process
of nanning, already described; but if not sufficiently
pure, the next operation, supposing it does not require
to he roasted, is iging; but as most of the tin ore of
Cornwall requires roasting, this operation is the next
part of the process.
The object of roasting is to get rid of ores of
copper, iron, or zinc, mixed with the tin ore. The
furnace in which the ore is fiurni, as the miners call
it, is a common reverberatory furnace: it is raised to
a dull red heat, and then about 7 cwt. of the ore
is put into it through a hole in the top. It is allowed
to remain for about an hour, to get rid of the moisture
imbibed in the previous processes, and is then spread
over the furnace, for about 41~ feet in length, nearest
the fire, and by means of an iron rake is turned about
every half hour, that the whole may be equally ex-
posed to the action of the fire. This is continued
until the ore ceases to give out whitish fumes, or,
when turned, to exhibit bright sparkles; it is then
withdrawn through a hole, now uncovered in the
bottom of the furnace, and allowed to cool. It is
then sifted, and after being. again tossed, huddled, and
again tossed, it is ready for the smelter.
In some cases, however, when the ore is only
partially roasted, it is taken out of the furnace and
sifted and huddled, and then tossed, chimmed, or
dillued: then roasted a second time. In this way
some ores are more easily cleansed from their impu-
rities than if they had been wholly roasted at once.
The ore in this half-roasted state is called rag-burnt ,-
when it has been huddled, the tails are considered
equal to the middle heads of the ore, which has not .
been roasted, and are accordingly tossed, chimmed, or
dillued. The skimpings of the tossed ore being again
huddled, the tails are thrown by as barn?! leanings,
and as they frequently contain copper, they are sold
as copper ore, if the copper amount to 2% per cent.
When the tin ores are mixed with those of copper
(generally the sulphuret) after roasting, the water in
which they are sifted holds sulphate of copper in
solution. The salt may he obtained by evaporation,
or the copper precipitated by the immersion of iron
plates into-the solution.

(1) The ore which subsides in the bottom of the dilluing vessel,
is termedflging, or dilZai-ng smalls, and is again huddled and tossed ,
or chimmed, with themiddle heads of the skimpings: the produce
thus obtained is termed round or leap ore, and is of the most in-
ferior description.

But some kinds of ore, after being roasted, require
iging. The tge is a long narrow inclined furrow,
through which passes a stream of water, three or four
times more copious than that used for buddling. The
ore being placed at the head, is agitated with a broom,
(or with a shovel when the tails of the buddles are







it'll/7'77‘; - ‘llltI/i-uil. I _




.r - f. _. - ‘\Hi' _ .
51%!“ (ll llllllllllllltn .k "11’. ‘:5 sf eels/a ..
' Lb/ 17/” e /E-'" Q
a a "
Fig. 1444. TYING.
tyed,) and the rough and lighter particles are carried
to the lower part of the tye. The ore at the head,
unless it requires to be again dillued, is lit for the
smelting-house. The remainder, if very poor, is
thrown among the leavings ; but if otherwise, it is
exposed to another operation called jigging.
This is performed by plunging a copper-bottomed
sieve, containing two or three shovelfulls of ore, into
a vessel of water. The operator, holding the sieve
in his hand, gives it both a vertical and rotatory




A it)‘ ‘.
In. a
‘ a.“
r
I
it it; ,
motion, taking care that it he never lifted above the
surface of the water; by this means the different
parts arrange themselves in the sieve in the order of
gravity; the lighter portions, being brought to the
top, are scraped off and considered as leanings, and
a fresh supply of ore is thrown in and jigged, until
the weight of the richer part, at the bottom of the
sieve, becomes too great for the operator; it is then
taken out in a state fit for smelting. The jigging-
mac/tine is sometimes used in this operation, but more
METALLURGY.
265 .
commonly in the dressing of copper and lead ores. Its - the lower end of the floor a vacancy of two or three
construction is very simple, and will be understood
by reference to the annexed engraving, Fig. 1446.
The foregoing operations apply to the 07'01) ; the
leanings, consisting of the slime, the tails of the bud-
dies, the s/cz'mmz'ags of the skimpings, and the slcz'mpz'vzgs
of the jigging, are subjected to a series of
operations known as firm/ring, frammg, or
raclrz'izg. Previous to trunking, a large sur-
face of the slime ore is generally exposed to
the air to get rid of moisture: it is better ‘ ,
if it be thoroughly dried, as the alternations
of dryness and moisture facilitate the sepa-
ration of the soft and earthy substances.
The tram/r consists of three divisions, viz.
the sire/re, the cheer, and the flute/z. The
streke is a furrow, about 5 feet long and
2,-1- feet deep: at the higher end it is 2%; feet
wide; but it becomes gradually narrower,
so that at the lower extremity it is only
6 inches : it is walled on each side. The ccver, which
is situated at the lower end of the streke, is a box
of about 8 cubic feet in capacity. The hutch, which
is separated by a single plank, is a wooden case
about 8 feet long, 2% to 3 feet wide, and about
a foot in depth: its bottom, as well as that of the
streke, is a little inclined. The slime being put into
the str‘eke, a stream of water as large as a circular
aperture of %ths inch in diameter will admit, runs
over it, and being occasionally agitated, a portion of
the slime is suspended by the water, and is thereby
carried into the cbver. Too much slime must not
be suspended at once: the best proportion is about
g-th or %th of the weight of the water.
The operator, usually a child, agitates the
water in the cover with a shovel, and causes
it to ripple over the dividing plank into the
hutch. The quantity passing over at once ,5;
is very minute, but the ripples succeed each
other rapidly, and by this means the best .5‘
parts of the slime remain at or near the
head of the hutch, while the poorer parts
are carried off by the water. When the
hutch is full, the contents are removed to
the frame or rack. The poorer parts of
the slime, termed £0068, may be ‘worth a
second trunking, which is not often the
case if the first operation be well per-
formed; and it is well performed if the
liquid in the cbver have an equal velocity
at the middle and sides. Trunking is often performed
by machinery.
The next operation is framing, or making, Fig.
14417 . The fmme table is about 8 feet long and 5
feet wide, with a rim 5 inches high round it. This is
suspended in an inclined position on pivots, but is
fastened by a kind of latch; at the upper end is a
jagging-board, similar to that of the huddle, which is
connected with a frame by a movable sloping piece of
wood, to prevent the ore from falling between the board
and the frame; below the frame are two boxes, which,






being placed end to end, extend its whole length: at
inches leaves an aperture for the escape of water.
The operator spreads on the jagging-board from 2
to 3 quarts of the slime obtained in the previous ope-
ration of {run/ring, and with a small toothless rake
makes in it small furrows, in the direction in which a
at
i l
a‘
a?!
\.
ll?
1
I
.1:
ii
Hm‘ w— i
L
“inf-fr”:*~~‘W‘“=Isil>~ ‘ a ‘ ~"
Fig. 1446. JIGGING MACHINE.
stream of water runs, which is let in upon the jagging-
board. By this means the ore is carried from the
board to the frame; the richest part rests at and near
the head, and the poorer parts further down; the
impurities are carried off by the water, and escape at
the bottom. ‘The operator runs the rake across the
frame to agitate the ore, and when the richer part ‘has
sufficiently accumulated, the jagging~board being swept
clean, the latch is lifted, and the frame turned on the
pivots from a horizontal to a vertical position, and the
ore is swept or washed into the boxes beneath, the
best into the upper, and the inferior into the lower
box. It is of importance that the water should pass '
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FEAMING OR BACKING.
Fig. 144.7.
of equal depth and velocity over every part of the
frame, or the difierent parts of the mass will be mixed
with each other, and some of the ore be carried off
with ‘the waste. If the ore deposited in the upper
box be contaminated with the ores of copper, iron, or
zinc, it is roasted, and afterwards treated the same as
that which has not been burnt; viz. it is sifted and
tossed: the lower part of the contents of the tossing
kieve is huddled, and again tossed, and it is then fit
for the smelting-house : the upper part is again framed
with a smaller stream of water. The ore deposited in
the lower box beneath the frame, may be again framed
266
METALLURGY.
with a fresh proportion of trunked ore; but it may be
tossed, and the richer contents of the tossing kieve
buddled. The ore at the head of the huddle, if not
requiring a repetition of the process, is tossed, and
is then fit for the smelting-house. The remainder is
again trunked, &c.
Fig. 1M8 represents the tools used at the racks
or frames: at is the scraper, cuthe broom, and c a
horn, for rubbing or washing the table.


,_ \ ~
a t \
‘P c-
Fig. 1448.
Very little improvement has been made in the mode
of dressing tin ores for nearly a century; but of late
years, improved machinery has been introduced at
some mines.
LEAD OaE.-—When the lead ore is raised to the
surface, it is sorted out into three parcels, called
lance/rings, riddlz'rzgs, and fell, the last-named being
that which passes through an inch iron-wire sieve, in
which the riddlings remain; the knockings are the
larger pieces of spar or stone, with ore intermixed.
The dressing of the orc does not difl' er in principle
from that already described for tin; it is, however,
much less elaborate, and many of the processes are
called by diiferent names. The buddling is carried on
with the water of a running stream, which frequently
has the effect of poisoning it. [See LEAD.]
The foregoing details will give a suflicient idea to
the general reader, of the methods adopted in this
country for concentrating ores by mechanical means.
Our steel engraving represents at one view the appa-
ratus used on the Continent for the same purpose:
w is an overshot water-wheel, which gives motion to
the different machines; the end of the canal which
supplies the water being shown at c. The prolonged
axis, d, of this wheel, furnished with a number of
cogs or wipers, which raise the stamps of the stamp-
mill, D. Here the ore is broken up into larger frag-
ments, schlich, and slime ores; the stream of water
which supplies the stamps passes into the basins, Iris,
where the heavier fragments are deposited; the water
then flows into the canals, Z l, and thence into the
canals, a a, where it meanders in the direction of the
arrows, and in the course of this long transit gradu-
ally deposits the mineral matters suspended in it, the
lighter and poorer particles being deposited last.
The washing of the ores is performed on the Conti-
nent chiefly by means of three diiferent kinds of ,ap-
paratus, viz. pervassz'orz sieves and tables, A and r ;
the German chest, E E, and sleeping-Midas, G G. For
the purpose of separating the crushed or stamped ore
intofragments of the same size, the percussion sieve
(Maze 5» secousses), A, is used. This apparatus con-
sists of twb troughs or boxes, A and t placed one

above the other, and set in motion by means of the
two rods, a i) and a’ [2’, which derive their jerking
motion from the wipers on the drum, cl, acting upon
uprights, to which the rods are attached by hori-
zontal connecting pieces. Water is conveyed into the
trough, A, by means of a shoot, 8; a portion of this
water passes into the lower trough, a‘, by means of the
small shoot, The bottom of each trough is formed
of meshes of iron wire, or of a strong metallic netting;
but themeshes are coarser in the box, A, than in the
box, t. The ore is thrown by means of a shovel into
the top ofbthe box, A, and the jerking motion im-
parted to it by the rod, a b, causes the ore to descend
upon the grating ;) Pone portion passes through the
meshes into the lower trough, a‘, where it undergoes a
second jigging. The ore is thus divided into three
sizes: first, those fragments which are too coarse to
pass through the meshes of the box, A, fall upon the
table, a ,- secondly, those fragments which pass through
the meshes of A, but cannot pass through those of the
box, 2‘; these fall into the box, it,’ and, thirdly, the
fragments which pass through t, are collected in a
box, 2, situated immediately below it.
The hand-sieves, which are still used in Cornwall,
are almost superseded on the Continent by the simple
arrangement shown at B: the mineral to be washed
is placed on a table, 1' ; B is a large tub of water, in
which the sieve, c, is suspended by the iron rod, 2' ;
the proper motion is given to the sieve by moving the
rod, 1%, up and down in the tube, 6; the rod, it, is
hinged to the horizontal beam, j w, to which also the
rod, 2', is attached, and at the extremity, w, of the
beam, is a box filled with small stones, for counter-
pcising the weight of the sieve and the rod, it.
A somewhat similar apparatus was formerly em-
ployed in Cornwall for washing the crushed copper
ores; but a more effective arrangement is now in use.
This consists of a large box, covered with a tight
wooden floor, in the centre of which is a circular me-
tallic trough, perforated with six holes, each about 2
feet in diameter, and into each of these openings a
sieve is closely fitted. In the centre of this arrange-
ment is a cylinder in which a piston works, and by its
motion alternately elevates and depresses the level of
the water in the box, and consequently also in the
sieves. By this motion of the water, the particles of
mineral contained in the sieves are arranged according
to their several densities, and when one sieve is re-
moved for the purpose of scraping off the less valu-
able and lighter portions of its contents, its place is
supplied by another kept ready filled for the purpose.
The German chest (caisse a z‘ombeaa), n n, is a
cofin-shaped box placed in a slightly inclined position,
at the lower end of which is a series of holes closed by
wooden pegs. At the upper end is a kind of raised
platform on which the ore to be washed is placed, and
in this a small stream of water is allowed to play;
consequently, the finer portions of the mineral are
carried oii' in suspension in the water, and deposited
at various distances from the head, depending on
their density. When the body of the chest is full oi‘
water, the stream is stopped at the head, and one of
I'l-Illl all u I II 1|" .I-.r.
.
3? M1. $2 .L“..U...,.< @922 @MQ advfigai Q 1%. $0.“... $93313.“ may...



M-n'ranrjnn‘er.~ "
267"
the pegs at thelower end being taken out, the water
and the lighter particles which'it holds in suspension
are drawn off into reservoirs, where the solid matter
is allowed to ‘subside. As the chest becomes gradu-
ally filled a higher peg is removed, and when the pit
is quite full the top peg only is taken out. The de-
posited ore is divided into three classes; the first, and
heaviest, near the head of the pit, consists of mineral
so far concentrated as to he often fit for smelting:
the second and third portions, which are much less
rich, are washed'over again in the chest, or are trans-
ferred to the percussion-table or to the ‘sleeping-
table.
The percussion-table (table it seeonsses), r, consists of
a wooden flooring attached to heavy wooden sleepers,
and suspended by four chains or jointed iron rods:
two of the chains near the head are attached to a fixed
wooden framework, and two others to a long forked
lever Z’ Z’, moving on centres 00, and capable of being
raised or depressed by a pin placed in the holes of the
upright n’; this allows the inclination of the table r
to be variedaso as to suit ores of different degrees of
fineness. The axle rf; set in motion by the water-
wheel w, is furnished with cams, 7*’, which act on a
wooden lever, L, the lower extremity of which is con-
nected with the swinging-table, F. By the motion of
the earns the lever first pushes the table back, and
then allows it to fall with considerable force against
two wooden stops. At the head of the table is a tri-
angular shelf (better shown in figure 6 G), furnished
with triangular pieces of wood, so arranged as to dis-
tribute the water uniformly over its surface. ‘The
mineral to be washed is placed in the trough T, where
it is mixed with water from the shoot lz, brought by
the channel g. It passes from the trough to the
triangular shelf, and then to the suspended table,
where it tends to arrange itself according to its
density, and settle as a thin deposit over the surface;
but the repeated shocks which the table receives
cause the particles to be again suspended, and- each
particle is repeatedly brought into such a position‘ as‘
to allow it to-arrange itself, with respect to other par-
ticles, according to its size and density, and thus to
become separated from the lighter earthy impurities.
In Cornwall this kind of work is done by a huddle, or‘
by a male, which answers to the apparatus next to be
described, viz. the sleeping-tables.
Sleeping-tables (mans dormantes, or jnmelles, z'.e.
twins, from the circumstance of their being commonly
arranged in pairs) are shown at ad of the steel en-
graving." They consist of two inclined planes, G a,
varying from 20 to 25 feet in length, with rims at the
long sides for preventing the water from flowing off
laterally. At‘ the upper end of each table is a trian—
gular inclined plane, of much greater inclination than
the tables, and furnished with triangular pieces of
wood already noticed. At the upper point of the
triangle is an opening by which the water holding
the mineral in suspension pours upon the inclined
plane. The mineral to be washed is placed in a small
trough above the'head, into which a 'stream‘of- water
constantly flows 5' here the pounded ore is kept in

agitation by a small wheel 20, ‘set‘in motion'by the
small overshot wheel .9, and this is worked by a stream
of water from pg’ through the shoot it. The mineral,
thus kept in suspension by continual stirring, enters
the head of the table through the aperture at the top
of the triangle: but the great inclination of the
triangular head prevents any deposit from being made
upon it, so that the whole of the mineral is passed 011
to the table, the densest and richest parts remain-
ing near the head, while the poorer parts are either
deposited lower down, or are carried by the stream
into the canals m m, in the direction of the arrows.
When a certain quantity of mineral is collected on
the table, the workman stops the flow at the head, and
with a broom sw'eepsthe mineral from the lower end
of the incline towardsthe upper end: this operation
is begun‘ at the points indicated by the dotted lines :
a stream of ‘pure water'is then. allowed to flow over
the table, which carries off any poorer particles which
may have become entangled with the heavier poi'tions.
A valve is then opened near the dotted lines, and the
contents of the table are swept‘ into hutches placed
below. The valve is then closed, and the operation
proceeds as before. As the hutches are thus filled,
their contents are generally transferred to the smelt-
ing-house. The inclination of the tables is regulated
by the state of the mineral: if in fine powder, the in-
clination is small; if coarse, the inclination is fixed at
a greater angle.
The various basins, mm, which receive the muddy
waters, form a kind of labyrinth of great extent: they
are connected with the different forms. of apparatus
at such points as shall ensure the reception of waters
similarly charged at the same point. On quitting
these basins the waters are received into large reser-
voirs, where the final deposit, is made.
Many other processes might be described relative
to the washingof ores, since these processes'vary
greatly in different localities, according to the nature
of the ore. The subject ‘is one that requires, much
skill and experience to extract from the ore its mineral
contents, without loss, on the one hand, and too great
an expenditure of time ‘on the other.‘ Of course, as
the mineral increases in value, the latter item is of
less importance than the former, as in the case ,of
gold,‘ for example. 'The great density of this metal,
compared with the siliceous and ferruginous sand, or
gravel, with which it is associated, renders its ‘separa-
tion an easy operation. In South America the practice
of hand washing is' adopted, the only instrument
being ' an ‘iron or _ p M
zine pan, Fig. 144:9, v1‘ l



held by the knob at _ -
"'4 / - §
the bottom, and by we: a
a peculiar manipu- - '
lation the hghter My. 1449
and stony matters
are suspended'and poured off, while the heavier re-
siduum collects in the cavity‘ at the bottom. From
this residuum the gold is separated by amalgamation.
In Hungary inclined tables are used; in Brazil and
‘elsewhere a cradle, 'the construction of which will
268
METALLURGY—MICA.
be evident on referring to Fig. 14:50. The soil in
which the gold is disseminated, is taken up in
buckets, and a bucketfull at a time is placed upon
the sieve: the man rocks the cradle with his left
hand, dips up water with his right, and continues
to pour it into the sieve until the earth is clear, in
which operation a nugget may sometimes be met
with too large to pass through the holes. When

Fig. 1450. ‘
a bucketfull has thus been washed, the man unships
the sieve and throws out the stones: another bucket-
full is then taken up, and when from 50 to 60 sievefulls
have been washed, the rocker is cleared out, and what
is deposited at the bottom is put into the washing-
pan, when the gold, being the heaviest, settles.
In Siberia, the Tyrol, and elsewhere, a kind of mill,
Fig.1a51, is used; in the former place,for concentrating
auiiferous sands, and in the latter, for collecting small
quantities of gold, previously extracted by amalgama-
tion from an auriferous iron pyrites. A number of







these machines are so arranged at different levels,
that the products of the first machine may pour into
the second, and so on. The pyrites is reduced by the
stamping mills to fine powder; a stream of water,
holding this powder in suspension, is conducted into
the upper mill by the spout s, and flowing through it,
passes by the pipe 8' into the second, and so on to
other mills. The fixed part of each mill consists of a
cast iron capsule c a, fixed by screws to the top of a
strong wooden table T 'r’. The centre of this capsule
is traversed by a rotating axis a w, to which motion
is imparted by the spur-wheels w w’. The upper and
movable part m is a muller of hard wood fixed to
the spindle an: by an iron collar Is. This muller has
externally the same form as the internal cavity of the
iron capsule, from the surface of which it works at
- the distance of about half an inch; but to its under

surface are attached a number of ribs which nearly
touch the bottom of the iron pan. The upper surface
of the muller is hollowed out into the form of a
funnel, into which is conducted the liquid slime, which
pouring into the space between the two surfaces,
flows over the sides of the basin by the spout s or .9’.
At the bottom of the iron pan is about half a cwt. of
mercury, which forms a stratum about é inch thick,
and with this the pounded mineral is constantly
agitated by the projecting ribs at the bottom of the
muller. The particles of gold are dissolved as soon
as they come in contact with the mercury, and those
which escape contact in one machine, are arrested by
the mercury of a machine lower in the series. The
machines are kept at work for 5 or 6 weeks, when
the mercury is drawn off and filtered through chamois
skin, which retains a solid amalgam of gold: about
ad of its weight is pure gold, which is separated by
distilling off the mercury. It is calculated, in Siberia,
that if the sand contain only 000000]. of gold it
cannot be worked to advantage. Some sands contain-
ing only gth this quantity, on the Rhine, for example,
are occasionally washed by peasants and others, when
more profitable kind of labour is not to be procured.
METER. See Gas LIGHTING.
MEZZOTINT. See ENGEAVING.
" MICA. A name given to a group of minerals
which are finely foliated, of a pearly lustre, trans-
parent’or translucent, tough and elastic. According to
Hauy it may be divided into laminae of the thickness
of only fig—OO—ath inch. The colours present various
shades of white, grey, green, brown, red, violet, and
black—silver white, greyish green, and black, being
the usual tints. It varies in hardness from 2 to 2'5,
and in density from 28 to 3. The micas present
several instances of isomorphism in the substitution of
some of the alkaline earths for others, and an instance
of di-morphism in the two varieties named wad-arm!
and (ii-areal mica. Poms/t or bé-amal mica, which is
the usual kind of mica, consists of silica 46'3, alu-
mina 36'8, potash 9'2, peroxide of iron 45, fluoric
acid 0'7, and water 1'8. It difiers from tale, in afford-
ing thinner folia and being elastic, and not having the
greasy feel of that mineral. It is one of the consti-
tnents of granite, gneiss, and mica slate; the lamellar
structure of the latter being due to it. It also occurs
in granular limestone. Mica is sometimes found in
plates 2 or 3 feet in diameter, and perfectly trans-
parent, in which state it is well adapted for use as a
substitute for window-glass. Its common use in this
way in Siberia, has procured for it the name of illus-
cot-y glass. It was also formerly used in the Russian
navy, on account of its not being liable to be broken
by concussions- It is still used in lanterns and in the
doors of stoves, and it is useful for holding minute
objects for the microscope.
Lz'flzia—mz'ca or Zepz'dolz'te.
replaces a portion of the alumina: it occurs in crystals
of a purplish colour, and in masses of aggregated
scales. '
In Magnesia—mica, or uni-axal mica, also called bio-
lite, a certain proportion of magnesia replaces alumina,
a
In this variety lithia.
MIC-A SCHIST—MILK.
269
which is present to the extent of about 15 per cent.
Fae/wife is a green mica, containing chrome. In
Piiimose mica the scales are arranged in a feathery
form. Rabeiicme is a name given to red mica. Mar-
garoliie, or pearly mica, is only a variety of common
mica. Hydrous mica contains 14' per cent. of Water.
MIGA SOHIST. One of the earliest groups of
stratified rocks, extensively distributed throughout
the mountain regions of the globe, often in contact
with granite or superposed on gneiss. It is also fre-
quently interstratitied with gneiss, primary limestone,
quartz rock, chloritic schist, and clay slate. Mica
schist, in its most typical form, differs from gneiss by
the absence of felspar. “ The mica is usually spread
through the rocks of this series in continuous surfaces,
overspreading the quartz portions ; whereas in gneiss
this seldom happens. In respect of the magnitude,
relative abundance, and crystalline aspect of the in-
gredients of mica schist, there is every possible varia-
tion, so that some specimens approach, obscurely, to
granite, others to well-defined gneiss, and others to
clay slate.”
MICROCOSMIG SALT. Phosphate of soda and
ammonia, prepared by mixing equivalent proportions
of phosphate of soda and phosphate of ammonia, each
in solution, and evaporating and crystallizing. A
slight excess of ammonia is an advantage. This salt
was originally extracted from human urine, and de-
rived its name from the alchemists, who regarded man
as a miniature of the world, or the microcosm.
MIGROMETER. An instrument by means of
which small spaces, or angles, or the apparent magni-
tudes of objects, viewed through telescopes or micro-
scopes, are measured with great exactness. It was
explained in the article LIGHT, that the inverted image
of a bright object formed by a convex lens may be
viewed by the eye-piece of a telescope, as if it were a
material body; and if at the point where this image
is formed, a very fine wire or a spider’s thread be drawn
across the tube of the instrument, it will be distinctly
seen with the image. In practice, however, the wire
is stretched across a sliding piece, which is moved by
a screw perpendicular to the length of the instrument,
and can thus be made to measure the image in terms
of the revolutions and parts of the screw. An instru-
ment of this kind is called a wire micrometer.
The micrometer screw, just referred to, is an impor-
tant part of every micrometer. The following is an
illustration of its use :—Suppose in the micrometer
attached to a microscope, the screw has 50 threads to
an inch, and carries an index which points to the
divisions on a circular plate fixed at right angles to
the axis of the screw. The revolutions of the screw
are counted on a scale, which is an inch divided into
50 parts : the index to these divisions is a fleur-de-lis,
marked on the slider which carries the needle-point
across the field of the microscope. Every revolution
of the micrometer screw measures Biath of an inch,
which is again subdivided by means of the divisions
on the circular plate divided into 20 equal parts,
over which the index passes at every revolution of the
screw. In this way we readily obtain the measure of

,0‘, th of an inch; since 50, the number of threads on
the screw, X by 20, the divisions on the circular plate,
: 1000; so that each division on the circular plate
shows that the needle has either advanced or receded
1010 0th of an inch.
There are other forms of this instrument, such as
the divided object-glass micrometer and keliomeier. If
an obj cot-glass be divided into two semicircles or semi-
lenses, and the two parts he moved one beyond the
other, each portion will form its proper image, and the
images will retreat from each other as the semilenses
are'moved. The semilenses are mounted on slides,
and the quantity of separation is read off upon a scale.
Another form of micrometer, known as the reiiczile, or
diaphragm, is a fixed arrangement of .wires or bars,
applied to a telescope for the purpose of measurement.
The circular micrometer consists of a metal ring set
in the centre of a perforated glass plate, the outer
and inner edge of the ring being turned true. “ The
plate is fixed in the focus of a telescope, and the ap-
pearance is that of a ring suspended in the heavens.
The telescope is pointed, and the observer notes the
time when a star disappears at the outer ring, re-
appears on the inner ring, disappears again, and finally
re—appears. If two stars be thus observed, it is clear
that when a mean is taken of the disappearances and
re-appearances of each, the difference between the
two means will be the difference of right ascension
between the two stars, and therefore that if one be
known, the other is determined. Again, if the dia-
meter of the ring has been determined, and the decli-
nation of the stars nearly known, the time of describing
the chord of the ring will give, by an easy eomputationg
the distance of the chord from the centre, and that,
the more accurately, the smaller the chord described.
The sum, or difference, of these two distances is the
difie-rence of the stars in declination.”1
MICROSCOPE (from pucpos‘, small, and a'Korre'w,
to see), an instrument for enabling the eye to see dis—
tinctly objects which are placed at a very short distance
from it, or to see the magnified images of small objects
not visible to the unassisted eye. The principle of the
instrument is explained under LIGHT. For practical
details we must refer to' special treatises on the
subject.
MILE (from miliare, the mile passes, or thousand
paces, of the Romans); The length of the mile differs
in difierent countries. The English statute mile is
8 fur-longs of 220 yards each, or of 4:0 poles of 5% yards,
or 16% feet each. It is also 80 surveying chains of
22 yards each. The mile in this country is therefore
1,760 yards, or 5,280 feet; the square mile is 6,400
square chains, or 6&0 acres. [See WEIGHTS and
Mnasunns]
MILK. A fluid secreted by female mammalia, for
the nourishment of their young, and it is admirably
adapted by its composition for furnishing materials
for the rapid growth and development of the animal.
The ingredients appear to be the same in carnivorous
as in herbivorous animals, but the proportions differ.
Milk contains, 1. an azotized matter, caseirze, which is
(1) “ Penny Cyclopadia,” article Micrometer.


270
. MILK—MILLSTONE.
nearly identical in composition with muscular flesh,
9.. faiig principles, 8. a peculiar sngar, and 4!. various
salts, such as phosphate of lime, held in solution in a
slightly alkaline liquid, and which contributes to the
formation of bone. Under the microscope, milk appears
to consist of a perfectly transparent fluid, with a
number of transparent globules (of fat) floating about
in it, the fatty matter forming a .mechanical mixture,
or natural emulsion with the watery solution. If left
to itself, at the ordinary temperature of the air, a large
portion of the fat globules collect on the surface, and
form what is called cream : if this be removed and
strongly agitated for a time (as in the operation of
churning, described under Bn'rrnn), the fat globules
expel the remaining watery liquid (batter-milk) from
between them, and unite into a mass, called batter.
The butter is washed, to get rid of the remaining
caseine, which soon putrifies, and a little salt is com—
monly added. If butter be intended for keeping, the
butter-milk is got rid of by clarification, as it is
called, or melting over a slow fire: the watery part
subsides, and carries with it the remaining traces of
the azotized matter. The flavour of the butter is
somewhat injured by this process. Butter varies in
consistence with the season, and probably also with
the kind of food consumed by the animal. In addition
to the fat, there is an oily portion, which is more abun-
dant in summer than in winter. This oily part ap-
pears to be a mixture of oleine and a peculiar odori-
ferous fatty principle, bnigi'ine, which has not yet been
isolated, but which by 'sapon'iflcation yields 4? dis-
tinct volatile acids ; viz. bnigrie, caproie, eaprglie, ‘and
eaprie. They exist ready formed in rancid butter and
in cheese, and may be obtained by saponifying butter
with potash or soda, adding an excess ‘of sulphuric
acid, and distilling. The resulting acid watery liquid
is saturated with an alkali, evaporated to small bulk
and distilled with excess of sulphuric or phosphoric
acid. The mixed acids are separated by taking
advantage of the unequal solubility of their barytic
salts : the less soluble salts of the mixture, amounting
to about 216th of the whole mass, contain capric and
caprylic acids; the larger and more soluble portion,
the caproic and hutyric acids. In the formulae of these
acids the carbon and hydrogen successively increase
by the addition of 4S equivalents :—
Butyric Acid ......... .. o, H, 03,110.
Caproic ,, .......... .. CMHMOB, HO.
Caprylic ,, .......... .. CmHuOs, HO.
Capric ,, CQQHHOS, H0.
The processes for converting the caseine of milk
into an important article of food, are described under
CHEESE. The milk may be heated to about 120°, and
then coagulated by rennet: the curd is next separated
from the whey by a sieve ; salt is added, and sometimes
colouring matter, and the whole submitted to a‘ strong
‘and ihcreas'iriig pressure, during which a peculiar kind‘
bf fermentation.takes'place, and principles are formed.
which impart‘ a peculiar taste and odour. The best‘
ofp’cheese, containing a good deal of fat, are?
made with new and the are-la raids with’ ._ . ._ . . ,
‘ ~ I ~ ' M .. he. .i .‘ tured;andacldwheustalled-i
skimmed milk. ' ' ’
n
"'_ by being fermented and‘ frequently'agitated,’
yields a kind of spirit, in consequence of the caseine
converting a portion of the milk-sugar into lactic acid,
and another portion into grape-sugar, which becomes
transformed into alcohol. Some of the Tartar tribes
prepare such a spirit from mare’s milk.
Fresh milk is feebly alkaline, but it soon becomes
acid from the formation of lactic acid.1 The alkaline
property is due to the presence of soda, which holds
the caseine in solution, and in this soluble form,
caseine has the property of taking up and retaining in
solution a considerable quantity of phosphate of lime.
Milk varies greatly in density; that of the cow is
generally about 1030 : but it varies in different
animals from 10203 to T0409. According to
Berzelius the specific gravity of skimmed milk is 1033
and of cream 10241. The following analysis of fresh
cow-milk is by Mr. Haidlen.2

Water.................. ...............873'00
Butter............................ 30'00
Caseine 48'20
Milk-sugar 43‘90
Phosphate of lime 2'31
,, magnesia........................... 0'42
,, iron 0'07
Chloride of potassium 1'44
,, 0'24
Soda in combination with caseine 0'42
1000'00
Human milk coagulates with difficulty: it usually
contains a larger proportion of sugar than cow-milk,
but differs but little in the other ingredients.
The influence of food on the composition of milk is
important. According to Dumas, no sugar is to be
found in the milk of carnivorous animals, or in that
of animals fed exclusively on animal food.
The method of solidifying and preserving milk is
stated in the article F001), PRESERVATION or.
MILLSTONE. In the article BREAD, the con-
struction and use of millstones in grinding corn are
explained; and it is also stated that the finest quarry
of millstones is near La Ferté-sous-Jouarre, in the
basin of Paris. We propose in the present article to
notice this quarry at greater length, and also to refer
to one or two other quarries where this comparatively
rare substance is found.
The millstone of La Ferté is found in a bed of
ferruginous and argillaceous sandstone, which in
' some parts is 20 metres thick. After passing through
' a stratum of sand from 12 to 15 metres thick, the
presence of the millstone is indicated by a thin bed of
ferruginous clay, filled- up’ with small fragments of
millstone, called. by the workmenvpipois. Then follows
a layer 41 .to- 5 decimetres thick, composed of larger
fragments of millstone, and then the bed itself, which
varies inthickness from 3. to 5 metres. This bed has
avery uneven, surface, and seldom yields more than 3
thicknesses of; millstones. Although spread over .a
considerable plain it is not always of sufficiently good
quality to beworked. - The good stone is discovered

h_i(1) Aecording'itoiDl’Arcet andfetit, cow’s inilk is sometimes‘
‘and,’ and sometimes'alkal'ine; alkaline when the cows are pas‘-
,(2) 'Annalen. derfifhemie .und, 'Pharmaeie, xlv. 263, guoted Fownes’s'Mariual'0f.E1ementa1-y Chemistry, 1850.
MILLSTONE—MINE—MINING.
271
by sounding. In some places it opens into vertical
cracks, which allow the stones to be got out vertically,
and these prove to be of the most durable kind. The
works are quarries, not mines, for the loose nature of
the superposed rock does not allow of the more
economical method of driving galleries underground.
The water, which is rather abundant in the works, is
raised by means of buckets, attached to balanced
levers which are worked by children, who raise the
buckets from stage to stage. When the quarryman
has arrived at the bed of millstone, he strikes it with
his hammer; if the stone yield a good sound it is
known to be of excellent quality and large size: if
the sound be dead or dull, it will separate in getting
out. The man then gets out a mass of rock and
dresses it roughly into a cylinder, which according to
its height will furnish 1 or 2 millstones ; he sometimes
gets 3, but never more than that number. He then
cuts a channel, from 9 to 12 centimetres deep, round
this cylinder for the purpose of separating it into 2
millstones, which he does by driving into the channel
two rows of wooden wedges, and then between these
iron wedges, which are gradually and equally driven
all round until the mass splits asunder. The man
occasionally applies his ear to the mass, to ascertain
that the line of fracture is following the right direc-
tion. When millstones of large size are required, the
fragments of stone are dressed. into the proper shape,
cemented together, and united by iron bands. Stones
of this kind are largely imported into England and
America. ,
This millstone is a siliceous rock, full of interstices
or small cavities (frasz'er), which retain the grain, and
the runner instantly reduces it to powder. The hard
portions (defense) do not themselves become abraded
so as to mix with the flour, as is the case with granites
and sandstones. Hence the great value of this stone.
The quarries of Tartarel situated near those of La
Ferté, are stated in the Jury Report, Class I., to be the
most important, the number of workmen constantly
employed there exceeding 200. The arrangement of
the ji'asz'er and the defense in the stone of these
quarries, is regarded as being best adapted to fine mill-
work. A complete collection of stones from this
quarry was forwarded to the Great Exhibition.
The condition of the tradeinISétQ is thus stated :—
2,600 stones at an average price of 250

francs per pair 325,000
200,000 segments at 3 fr. 50 c. each .... .. 700,000
Total value in francs in 18%!) ....... .. 1025,000
At Nieder Mendig, not far from Andernach, on the
Rhine, is a deposit of millstone which has been
worked for upwards of 2,000 years. The rock is
described as being a very hard porous lava, about 5
miles in length and 3 in breadth, and is supposed to
0c the product of an extinct volcano in the neigh-
bourhood. The principal quarries are '7 in number,
and the average depth is 50 feet: they are situated
on an extensive plain named Hacher, about half a
mile from Nieder Mendig. There are 41 classes of
workmen: the qnarrz'ers, who get out the stones‘; ‘the
lifters, who raise them to the surface by machinery ;

the cutters, who bring the stones to the required shape,
and the labourers, who pile the stones in heaps or assist
in loading the vehicles which are to bear them away.
The quarry has the appearance of an inverted cone,
or of a funnel without its stem. The diameter at the
top is about 25 feet, at the ‘bottom 12 feet, and the
depth 50 feet. A narrow but easy path winds spirally
round this cone or shaft, by which the men ascend and
l descend. At the bottom the work proceeds horizon-
tally, and the roofs of the numerous galleries formed
by the excavation are supported by prismatic pillars
of millstone. As very little machinery or capital is
required to sink a shaft, 4! or 5 poor families unite
their means to sink one; but the task of excavating
50 feet of solid rock is laborious. After passing
through various layers of gravel and lava, they at
length arrive at a layer of hard, blackish, heavy stone,
regularly porous, and yielding sparks when struck
with iron. This is the millstone. Good and well
prepared tools are required to work it, after the
masses have been separated by wedges and levers.
The stones are brought into shape by hammers and
chisels. A deep socket is cut through the middle of
such stones as are intended for runners or upper
stones, and the lands and furrows on the surface are
produced by a double-edged hammer weighing M lbs.
The stones are sent down the Rhine upon the im-
mense timber rafts which are annually sent to Holland.
At Andernach the numerous small rafts of timber
with their millstone cargoes are united into one large
raft.
MILLSTONE-GRIT. See Gnrr. _
MILLWORK. See BREAD -—-WHEELS -—_WIND-
MILL—COUPLINGS, &c.
MINE—MINING. The ores of the most useful
metals are seldom found on the surface of the'earth ;
they are mostly buried beneath the soil, and penetrate
the solid rock often to a considerable depth: hence,
if not discovered by accident, or indications of their
presence do not exist on the surface, they must be
sought for by intelligent inquiry, and when discovered,
such methods of extracting them and raising-them to
the surface must be adopted as-vvill 'be likely to pro-
duce a profit to the \=owners. This constitutes *both
the art andthe science of mining.‘ ' ‘It is an", art, in-
asmuch as'it depends for its success on the application
of rules and fnuch local experience; and it is a science,
inasmuch as it admits of the application of philoso—
phical principles. The most successful miner he
who knows how to combine practice with theory.
In a .general sense the word mine is an opening
underground from which anything is dug, and it ap-
pears to be derived from the Latin nzz'nare, a word of
the lower ages, signifying dacere, to lead; hence to
draw, or lead'a way or passage underground. Until
the opening is made, the term mine is not properly
applied; although it is generally used to signify the
coal, iron, lead, &c. before the opening is made for
digging them out.
The nature of operations has been already
treated of at some considerable length in our article
Conn, and although the extraction of metallic ores
272
M lNE—MININ G.
requires, in many respects, different modes of treat-
ment, compared with the getting out of the deposits
of coal, yet the general features of the workings are .
v similar in both cases. In one respect the mining of
metallic ores has an advantage over coal, in being
entirely free from the inflammable gas which is the
cause of such terrible explosions in collieries.
The use of ' metals was almost coeval with man’s
existence on the earth. The Sacred Record states
that Tubal-Cain, the seventh in descent from Adam,
was the instructor of every artificer inbrass and iron:
hence, at this early period, processes were adopted
for reducing the ores, and so combining them as to
produce the alloy brass. Profane history also con-
tains abundant evidence that the earliest nations of
antiquity, such as the Greeks and the Egyptians, were
well acquainted with certain metals. They had gold
and silver in abundance; the Greeks used an alloy of
copper and tin for their armour and weapons, and iron
was not unknown to the Greeks and Romans. In
these early ages, however, those metals which were
found at or near the surface were used, and it is pro-
bable that the superficial deposits of gold, silver, cop-
per, tin, &c., - were then much more abundant than
they are at present, except in the case of gold, which
is now found plentifully in California and Australia in
positions which require little or no knowledge of
mining. When the Bhoenicians traded with Cornwall
for tin and lead, the rude natives obtained the. supply
by means of stream-works, as they are called. The
beds of mountain streams, and the gravel or loose
stones brought down into the valleys, often afford
indications of metalliferous veins higher up the coun-
try. By collecting this ‘sand and gravel, and throwing
it upon an inclined plane,» upon which a stream of
water is conducted (whence the term stream-works),
the lighter stones and earth, are washed away, and the
ore remains behind. In our own country these stream-
works are confined to the ores of tin, but in other
parts of the world gold, platinum, and other metals


‘i.
N‘. \
4.7/./*‘”-"

l!
/ ,
Fig. 1452.
are distributed in small grains in the'sand in a virgin
state, and are separated by sifting and washing. In
the island of Banka, in the Eastern Archipelago, as
much as 3,500 tons of tin have been annually ex-
ported, the produce of stream-works. The starmi-
ferous gravels of Cornwall are not, however, usually
5 upon the surface, but are covered by other gravel or
p by sand, clay or peat, which must be removed before
the rock is reached on which the tin stones rest. The
ore thus separated from the ‘lode is known in Corn--
wall as the 5702'; of the lode. In Fig. 14152, A is the
fiend of the lode, c o the broil, diminishing in size as

77/“:
1 g /
/ / {4411/ its .

it gets further from the lode, and becoming very
small as it gets nearer the surface B B E. The stream-
works of Devon and‘ Cornwall were formerly the
chief source of tin ore, but they are now nearly ex—
hausted. Streaming for tin is still carried on upon
St. Austell moors, at the Pentuan Valley, and in other
parts, but the chief supply is furnished by mine
workings.1
The ancients did not, however, depend entirely on
stream-works for their supply of metals. According
to Herodotus, a mountain in the island of Thasos was‘
completely burrowed by the Bhoenicians in their search
for the precious metals; and it appears from Diodorus
that the art of forming shafts and galleries for ex-
ploring mines and extracting the ores was well known
in Egypt. Early, in the fourth century before the
Christian era, the silver mines of Laurium in Attica
were worked by the Athenians, and the quicksilver
mines of Almaden in Spain were worked by the
Romans.
Mining, in this its proper sense, was certainly'car-
ried on in Britain before the Roman conquest and
during the Roman occupation. After the Romans
had abandoned Britain, this art, in common with many
others, fell into decay, the necessary consequence of
civil commotion. For a long period our mines were
worked by foreigners, and after the Norman Conquest,
chiefly by Jews. In the reign of Elizabeth, the Ger-
mans, who had long been celebrated as skilful miners,
had inducements held out to them to settle in this
country, which they appear to some extent to have
done. In the _ following reign, Sir Hugh Middleton
expended the revenue which be derived from some
lead and silver mines in Cardiganshire, in supplying
London with fresh water by means of the New River.
About this time the introduction of gunpowder into
mining operations led to many decided improvements.
The first use of this powerful agent is said to have
been made in 1620 in Hungary or Germany, and in
the same year it was introduced into England at the
copper mine at Ecton in St'afiordshire by
some German miners brought over by Prince
Rupert. It was not, however, used in
Cornwall until a considerably later period.
Early in the 18th century Cornwall rose
into increased importance from the recogni-
tion of the real nature of those immense de-
posits of copper ore, which had either escaped
notice in consequence of lying much deeper
than the tin, or had been confounded with
mundz'c, as the common iron pyrites was called.
In pursuing these" stores to greater depths than
had hitherto been attempted, and in places where
hydraulic machines could not be applied, the miner

(1) We need only just allude to the use of divining rods and
other superstitious means resorted to by miners when searching
for Veins 01-‘ mineral deposits. Certain atmospheric phenomena
popularly called burning d-rakes, by their apparent fall to the
earth are even now thought to point out the situation of rich and
undiscovered veins of ore. Whistling in amine is‘ thought to
frighten away the ore or diminish its chance of continuance,
and hence, however much miners may sing or halloo at their
work, no boy or man is allowed to whistle.
MINE—MININ G.
273
soon felt the want of some powerful apparatus for
pumping out the water’ which threatened to submerge
his works. The first practically useful engine was
constructed by Savery, who, in his “ Miner’s Friend,”
described its application to the draining of mines.
This engine was'greatly improved by Newcomen, and
in 1705 was made the subject of a patent in the
names oft-he two inventors. Their steam. or, rather,
atmospheric engine, continued to be of great assist-
ance, not only in the mines of Cornwall, but also in
the coal mines of Staffordshire and the north of Eng-
land,>and it is not even yet entirely out of use, for
in the autumn of 1852 the writer saw a Newcomen
engine in successful operation at a coal and iron pit
close to Coatbridge, near Glasgow, and the man who
attended it stated that it had been at work for more
than 13 years without requiring a single repair. In
17 65, and the succeeding years, Watt introduced his
improved engines into Cornwall, and their increased
power and greater economy of fuel (the whole of which
is brought from South Wales) produced the most
beneficial effects on the mining interests of that
county. Since the time of Watt, the Cornish engines
have been in a constant state of improvement, their
power having gone on improving without greatly in-
creasing their demand for fuel: this, together with
improved pumping machinery, has enabled proprietors
to increase the depth of mines which would otherwise
have been abandoned. The improved pumping ma-
chinery was one of the consequences of the improve-
ments made towards the end of the last century in
the manufacture of iron, the clumsy old wooden
pumps having been replaced by those of iron of far
greater extent and efficiency. -
To the same source may also be referred the intro-
duction of iron tram-roads, underground as well as
on the surface, by which much labour was saved in
conveying the mineral to different parts of the works.
Great improvements were also made in the arrange-
ment of the underground works : the present system
of laying open the ground for discovery and extraction
by a well-arranged series of shafts, levels, and winzes,
came gradually into use, instead of the old plan of fol-
lowing down the ore by irregular isolated excavations,
and of stoping or cutting away the ground in the
bottom of the levels, as is still practised on the
Continent. Not the least among modern improve-
ments is the man-engine, or mechanical lift for raising
and lowering the men. The labour of ascending and
descending deep mines is so destructive to health, and
so greatly deteriorates the working powers of the
miner, as to point out the strong necessity, if only on
the score of humanity, of adopting this excellent con-
trivance. The improvements which have taken place
of late years in the mechanical preparation of ores
are noticed under METALLUBGY; and we cannot con-
clude this brief historical notice without mentioning,
as an important improvement in our system of edu-
cation, that a school of mines, and a mining record
office, have been attached to the Museum of Economic
Geology, and that similar institutions have been and
are being planted in the mining districts of this
VOL. II.

country. A few years ago the Government also insti-
tuted a geological survey of the United Kingdom.
The resulting geological map of England is thus re-
‘ferred to in the Jury Report, Class I.——“ It is exe-
cuted on the ordnance map prepared and published by
Government. The scale of this map (1 inch to a
mile, or 1 in 63,360) is sufficient to represent in detail
the outline or the boundary of all the geological for-
mations, and it even allows the direction of the prin-
cipal metalliferous and other veins to be indicated
when they are known for any distance. This great
work, at present the only one of its kind, is a model
which we may hope will be imitated by the principal
governments on the Continent. Science may then,
within a limited time, be enriched by a complete geo-
logical map of the whole of Europe. It'is true that
France ah'eady possesses a geological map, and there
are also a number of departmental geological maps,
many of which are executed with great talent; but
these are not all on the same scale, and the details
are not of the same kind; so that there are certain
discrepancies which prevent our being ‘able to unite
them all in a single sheet, and thus form a ‘complete
result. The new map of France, which is in no respect
inferior to the ordnance map of England, either in
accuracy or execution, furnishes the groundwork for
a geological map equal to that which has been pre-
pared by Sir H. de la Beche and the officers of ‘the;
England, which laid the first
geological survey.
foundation of the truestudy of stratified deposits by
the sections of W. Smith, and the important map of
Mr. Greenough, has still the honour of giving to the
world-a model for the execution of a detailed geo-
logical map, applicable at once to industrial researches
and agricultural improvement.”
SECTION ,I—ON run Drsrnrnurron or METALLIC
Cans.w I '
Some acquaintance with geology is required to form
an accurate notion of the various methods in which
the metals and metallic ores are distributed in the
earth’s crust. We have seen in the case of COAL and
Inon, that these important mineral substances may
alternate with beds of rock of great "extent, as South Wales and Staffordshire. In other cases the
mineral. may occupy cracks or fissures, which have
evidently been produced in various rocks by mechani-
cal violence, subsequently to their deposition.‘ These
cracks may be formed in stratified or in non-stratified
or igneous rocks; the mineral substance which fills
them difiers more or less from the rocks themselves,
and ‘is commonly known by the term oeia if the con-
tents be metallic, and rig/lie if non—metallic. [Dykes are
shown at n n, Fig. 572, article Conn] Non-metal-
liferous veins, usually accompanying veins of ore, and at
right angles thereto, are also called cross courses. By far
the larger number of veins are dykes, or cross courses,
containing no metallic ore, or not enough to make them
worth working. Should they be at all metalliferous,
the minerals are seldom of the same kind as those
occurring in the other lodes. Crystalline quartz and
clay are chiefly found in these cross courses. The
r
2'74
MINE—MINING.
interruptions which occur in the original veins forming
what are called faults and slides, are frequently pro-
duced by cross courses. The veins which contain
metallic ores are termed locles, and the rock in which
the lode is found is called the conning. The dip, or
inclination of the vein towards the horizon, is termed
its hade, slope, or underlie, and its intersection with
the surface forms the sirihe, and determines what is
called the run, or direction of the vein. The walls, or
portions of rock which enclose the vein are called the
roof and the floor ; and if the vein have a considerable
inclination the upper boundary of the vein is termed-
the hanging wall, and the lower the fool wall. When
a vein continues to be straight, it is said to be regular;
but if it swells out in some places and contracts in
others, it is then called a pipe vein. The expansions
are termed hunches. Small veins passing off from the
ore to the rocks are called slrings, and when very
small, threads. These terms
are illustrated by the various
dimensions of the vein a h e
d, Fig. 14153. The minor
sometimes reaches a piece
of dead ground, where the
vein divides into branches,
a string of ore extending on
either side; the vein or lode
\. \ is then said to take horse, as
_ it‘ . at f g.
~. ' Veins vary greatly in en-
ieni; they may run 5, 10,
or more miles through a
country, and after having
been followed to a consider-
able depth, he abandoned
on account of the diificulty
of working them. Veins
also vary‘ considerably in wia’z‘h. A vein may expand
.to 8 or'IO feet, and‘ contract toan- inch or two across.
Its value, however, does not altogether depend on its
width, since a broad vein may be poor, and a narrow
one rich. In Cornwall some veins 30 or 40 feet wide
are less productive than- those which are only one-
tenth that width; while some veins, from 2 to it inches
wide, areso rich as amply to repay the. working.
It has been observed that productive veins nearly
always run east and west ; they are then termed right-
rnnning .veins. The veins of lead in North Wales,
Cumberland, Yorkshire, and Derbyshire, and the veins
of copper in Cornwall, are mostly right-running. A
similar observation applies to the veins of the mines
in Brittany, the Harz, Hungary, and Mexico. The
unproductive. veins or cross courses, on the contrary,
generally run in north and south lines across the
metalliferous lodes. Veins usually occupy a nearly
vertical position in the rocks; difiering therefrom in
the north of England seldom more than 10°; in Corn—
wall the deviation is said to average 20°, and in so me
instances to be as much as 415°.
In Comwall'the upper part of the veins are usually
filled with clay, gravel, and debris, as at a, Fig. M53;
so: that indications of metal ‘ are rarely. met with at


a less depth than 80 feet. The mineral contents
of the vein have been divided into the veinstone or
gangne and the ore, the former consisting of silica, or
fluor-spar, or carbonate of lime, &c., all in a crystal-
line state. These minerals enable the miner to form
some estimate as to the abundance or scarcity of the
ore. The ore usually occurs in small veins within
the principalvein, or in grains or crystalline masses
and disseminated crystals. Where the veinstone is
earthy or powdery, there is said to be generally much
ore, while sterileveins are commonly filled with sand-
stone or clay, or with broken fragments of the ad-
joining. rocks. A vein does. not always become
richer as its depth increases; but it generally happens
that where the rock changes in hardness and texture,
or to ore of a different character, there is an altera-
tion in the value of the lodes. It has been remarked
in Cornwall, that a vein producing copper ore in
slaty ground, may enter granite without any break or
change of direction, and become at first richer, and
furnish ores of a different mineral~ character; but if
traced far into the granite, it generally becomes poor.
When a productive vein crosses an clean or granite
dyke, the ore in some cases becomes rich and abun-
dant, and in others disappears altogether. As a
general rule, the most productive veins are situated
near the junction of two different kinds of rock; as
in Cornwall the most productive tin and copper veins
are situated chiefly in a species of clay slate, termed
hillas, and either near its junction with protruded
masses of granite, or where it is intersected by
channels of porphyritic rock or elcan. The lead veins
of Wales and the north of England are chiefly situated
in the carboniferous limestone and its associated
rocks, especially where they are intersected and
broken up by enormous faults and dislocations.
It is evident from the structure of veins that they
are of more recent origin than the rocks which contain
them; nor are the veins themselves of the same geo»
logical age. Werner “showed the probability that
cracks and fissures which may hereafter become
mineral veins have ever been, and are still forming;
and he directed attention to the fragments of adjacent
rocks, often found in veins, as a proof that the filling
up of the veins must have been subsequent to the
consolidation of the rock. But he also asserted,
from observation, the important fact, that veins in
tersect one, another, a vein of newer origin often
displacing an older one, breaking its walls, and
altering its texture and contents at the place of
contact. A more modern fissure also often extends
through the adjoining rock into an older one, and the
two veins join and run parallel for a short distance,
while sometimes a new fissure is permanently stopped,
coming in contact with the tough walls of a former
vein.” Fig. 1454:, which shows veins crossing one
another, is copied from the Neuhoffnunger-Flachen
mine, near Freyberg, in Saxony; and such an inter—
section of veins “ can only be rationally explained by
supposing that the intersection which has taken place
was accompanied by a slip or fault, which has pro-,
duced the shifts observed in the older vein.” As a,
MINE—MINING.
275
further illustration of the complication arising from
the intersection of veins in faulty ground, Professor
Ansted gives a vertical section, Fio‘. 14:5 5, from Huel
Peevor mine, in Cornwall, in which the tin vein a has





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has carried them downwards to the north N; and,’
lastly, the fault (Z has again heaved a portion of a.
upward to the south. Cases of this sort are very-
embarrassing to the miner.
These remarks respecting mineral veins may be
summed up by the following general conclusions :—
1. That mineral veins are of various ages, and quite
independent of the age of the rock in which they
occur. 2. That the fissures which now form mineral
veins have not been filled up without some reference
to the nature of the rocks in which they are contained,
and that the filling up was therefore most probably
subsequent to the formation of the fissure. 3. That
the fissures which contain metallic ore are chiefly in
certain definite directions, constant in the same
locality in most cases, but that these are crossed
nearly at right angles by another set, which are un-
productive.
*e ()PERATIONS IN Non-smur-
FIED Rocxs.
Such general deductions as these, the result of
much geological investigation, guide the miner in his
SECTION II.—

search for veins of ore. Lodes have been discovered
accidentally during the formation of roads, and other
operations requiring the removal of the surface soil.
The operation of boring [see Bonrne] may also be
resorted to for the discovery of ore; but there are
usually indications of the presence of a lode at a con--
siderable distance from its outcrop, such as springs
of water impregnated with metal, or the shoadstones
already noticed (Fig. M52). By tracing these frag-
ments of ore until they increase greatly in number,
the upper part of the lode may be discovered. This
method of tracing out the vein is called s/zodz'rzg or
sizoarlz'ng. Should this method, however, fail, trenches
are opened in the alluvial soil, so as to expose the
solid rock, the direction of such trenches being made
at right angles to the position of other veins in the
neighbourhood. In Cornwall this method of finding-
veins ‘is termed cosz‘eerzz'rzg. A more efiectual, but ,
more expensive method, is to excavate a nearly hori-
zontal passage, termed a level, draft, credit, from
the bottom of the nearest valley into the solid rock,
in the same direction as the trenches, and in this
way to cm‘ or intersect any mineral deposit which
may exist. This plan, however, is too slow and
costly to be adopted, unless the existence of the
mineral veins be beyond doubt. Should the direction
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Fig. 1456. snxzcr AND LnvnL.
of the lodes in the neighbourhood not be known, or
it be uncertain whether the country be traversed with
mineral deposits, shoad-pits may be formed at right
angles to each other; and in this way the vein, if it
exist, is almost sure to be detected. Such researches
as these are not, however, of very frequent occurrence,-
since ,the chief mineral districts of this and of most
‘other countries have been explored for ages, and the
T2
276
MINE—MINING.
mineral deposits well known and worked. New dis-
coveries are chiefly made upon untried portions of old
veins, or by excavating passages or cross-cats in a
direction transverse to that of the vein upon which
they are driven, so as to prove the adjoining ground.
But supposing a new vein to be discovered, and it
appears to be desirable to work it, the first step is to
obtain the consent of the proprietor of the land, or
of the person to whom the mineral right belongs;
and the next to form a company, order to raise the
necessary capital, and to . distribute the risk and
responsibility, Before operations are actually com‘
menced, the hearing or direction of the vein must be
ascertained, and also its dip or underlie, which may
be done by sinking a few shallow pits upon it. The
miners can then commence operations with precision,
and they have one of two courses to adopt: they may
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either sink a shaft from the surface down upon the
vein, or they may intersect it by a horizontal one
(called a level or edit) originating in some neigh-
bouring valley, or in some point on the slope con-
veniently situated for the purpose. If desirable, both
methods may be carried on simultaneously. The
shaft is, however, the most expeditious, and is usually
adopted; and it' may be sunk in an inclined direction
upon the course of the vein, or if intended to bever-
tical, it is begun upon that side towards which the
‘vein inclines err-underlies, and at such a distance from
its "back or outcrop, as to come down upon it a given
depth, such as 10, 20, or 30 fathoms, depending HPOII
the means of the company and the prospects ‘of
success. The shaft is not sunk in the vein itself,
even supposing the latter to be nearly vertical, and
to affordapparently the best facilities for doing so;
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seem/4%”
for as the vein is in general of a more friable nature
than the rock which encloses it, a shaft sunk in it
would not be secure. The shaft is therefore sunk in
the solid rock, and on reaching the vein, the miners
alter their course from a vertical to a horizontal
direction, or, in mining language, they cease to sink
and begin to drive. A level is driven upon the vein
in both directions; each level or gallery being made
about 6 feet high, 3 or 4: broad, and rather smaller
above than below. These dimensions, however,
depend on‘ the width of the vein; on its richness or
poorness, as well as on the nature of the rock.- If-
the shaft is intended ‘to cut the vein at any consider-
able j depth, it is desirable to approach it above the
point vof intersection by a cross-cut, and then to drive
two levels at the point where the cross-cutmeets the
vein..- "In some cases, several cross-cuts are made at
distances of 10' fathoms asunder, ‘and levels are
ELEMENTARY SECTION OF A COMNISIIMINE.
driven from each. As soon as the vem is reached
the shaft may be continued perpendicularly through
it, or obliquely upon the vein. The former is the
more tedious and expensive plan, but, in the end, far
more advantageous; the latter is the quicker and
cheaper mode; it renders cross-cuts unnecessary, but
it is badly adapted to the application of pumps and
machinery, an evil which increases with the depth of
the mine. , '
If, after cutting .the vein, the shaft is sunk perpen-
dieularly to the depth of 10 fathoms below the point
of intersection, another cross-cut is made into it; but
as the shaft is‘ now on the other side of the vein, the
cross-cuts into it be in an opposite direction to
the former ones; and as in approaching the vein they
become shorter and shorter, so now, in receding from
it, their length is increased. At the points of inter-
section, levels are'driven from 'the'cross-cut upon the
MINE—~MININ G.
277
‘course of the vein, and in this way the shaft increases
in depth, and the levels in number at the depth of.
every 10 fathoms, or thereabouts. Of course it is
understood that ore in suificientv quantity has been
found in the upper levels to warrant the continuance
of "the work. Wev are, in fact, supposing the case of
a successful mine, although there are cases where
the sum of 100,000!. has been expended before the
workings began to be profitable. These details will
be assisted by reference to Fig. 1457, in which the
perpendicular lines are shafts, and the single lines are
veins of ore. The first long horizontal line is an arlz't:
the other horizontal lines are levels and cross-cuts
of different lengths.
As the depth of the workings increases, the want of
ventilation begins to be felt, especially in the ends
of levels and those parts most distant from the shaft;
so that the baclness of the air arising from respiration,
the burning of candles and the firing of gunpowder,
compels the adoption of some method of ventilation.
The simplest contrivance and the one usually adopted
is to sink a small pit or 2112:7226 upon the vein from the
upper level to the extremity of the one below it. By
this means an ascending and a‘ descending current of
air is produced, and the level is properly ventilated.
This plan allows the levels to be continued for avery
considerable distance on each side of the shaft, and.
winzes are formed between them at convenient inter-
vals. By means of these winzes, also, the miner is.
able to examine the vein in the space between
two levels, and to divide it into solid rectangular
masses, which he can examine all round, and. thus
form an estimate of the resources of the mine. By
properlyr laying open the vein- the ore may be worked
away around dead unproductive pieces of ground
which are left standing .to support the rock on each
side of the vein, and thus supply the place of timber-
ing. This system of winzes is found so very con—
venient that where the ore is tolerably continuous in
driving a level, winzes are generally sunk at intervals
of‘ 20 or 30 fatl-ioms- In sinking winzes to connect
the lower levels with each other, they are usually
placed midway between the winzes above, so that the
ground may be explored under the middlev of the
rectangle formed-‘by the two upper winzes, and the
levels between which they are placed. Should the
ore extend above the upper level, this part of the
vein is laid open by perpendicular excavations or
rises similar to winzes, but formed by rising up in»
stead of sinking down. As we have already stated,
the extraction of ore is not the primary object of
these early workings, but should orey ground. occur
in the 6d6d7 or upper part of the level: first driven,
it is pursued upwards towards the surface, and yields
the> first returns to’ the company. W hen the mine
has been laid out into ‘the solid rectangular masses
already noticed, other arrangements will also be in
an effective state, so that gangs of men may be
set to raise the ore from the most productive
points. If the veins be not very hard it may be
removed with the pick, but it is usually necessary
to employ the force of gunpowder for the purpose.

The men generally work upwards from the back or
upper part of one level towards the bottom of another,
and the excavations are so contrived that the ore
may fall down to the level below them, whence it is
conveyedin tram waggons to the shaft, and thence
raised to the surface. It is usual, in well regulated
mines, not to remove all the ore which can be ini—
mediately got at, but to leave it here and there to be
worked as the general prospects of the mine may
require, and to which the miners return if less ore be
raised than could be wished. The ores thus kept in
reserve are called the eyes of the mine, and are often
of great value. When it is necessary in abandoning
the mine or from other causes to remove them, it is
called “picking out the eyes of the mine.” Fig.
1458 shows the top of a winze, with a man winding
up a Mable, or iron ' "i" “
bucket in which the
ore is raised. The
kibble is usually made-
of sheet iron: it
holds about 3 cwt. of
ore, and it is esti-
mated that 120 kib-
bles will clear a cubic
fathom of rock.
The method of
ventilation by means-
of wines fails to
answer the purpose
intended when the
levels have been ex- Find-‘158-
tended very far from the shaft: the conveyance of
ore, rubbish &c., from these distant. points to the
shaft becomes more inconvenient and costly; so that
if the prospects of the mine are favourable, a new
shaft must be sunk on one or both sides of the old
one, according to the direction in which the ore
extends, and. so placed that the new shaft may com2
mand that portion of the ore which is inaccessible
from the old- one. In forming the new shaft, cross-
cuts are avoided as much as possible, and hence the
new shaft will be made ‘to intersect the vein at ‘a
point much deeper than the former, and arranged so
as to correspond with one of the deeper levels, or with
one still deeper which remains to- be formed. The
new shaft is sometimes sunk while the levels which
are to open into it are yet distant: but the work is
expedited by driving levels from the new shaft to
meet those of the original shaft, and when once the
two shafts are thus united, the advantages become at
once evident in improved ventilation and increased
facilities for getting out the ore, &c. 'As it is of
great importance in a flourishing mine to get this
second shaft into operation with all possible speed,
an ingenious plan is adopted where the workings have
advanced near the point where a shaft is required.
The site of the shaft being determined and marked
out at the surface, the length, windings, and direc-
tions of the levels are accurately measured, and data
are thus formed for deciding the exact spot in each
level whichwill coincide with an imaginary vertical


278
MINE—MININ G.
line. It is next ascertained in what direction and to
what distance cross-cuts must be driven from each of
these points in the supposed vertical line, in order to i
decide upon the position of another vertical line im-
mediately below the site of the new shaft. These
nice calculations and measurements being‘ completed
to the satisfaction of the mining surveyor and engineer,
a number of excavations are made simultaneously
upwards and downwards in different levels, cor-
responding with the form‘ and dimensions of the
intended shaft which is at the same time being sunk
from ‘ the surface; and so accurate has been the
survey that all these separate ‘portions of a vertical
shaft unite with such exactness, that daylight may be
seen from the bottom of a deep shaft formed in this
manner. It is evident that by this plan much time
is saved, for by working at many points simultaneously
theiw'ork of many years" may be performed in one or
In consolidated mines of Cornwall, such a
shaft, 204: fathoms in ‘depth, by being worked from 15
different points at once was completed within 12
months. ' _ >
As a mine continues to‘ be worked, the various
excavations assume. a‘cfomplicated character in conse-
quence of the irregular distribution of the productive
parts of __thc vein, causing some-parts to be worked
more than others. Cross-cuts, too, are frequently
made at various depths with a view to discover side
veins, or to make trial of branches which diverge from
the main lode. As the depth greatly increases, the
first shafts may become useless, either from being
inclined, and therefore inconvenient for machiner , or .
from having intersected the vein too near the surface,
thus requiring very long cross-cuts before deeper levels
' can be begun. Hence in very deep mines a double line
of shafts will
often be sunk






7”
, /‘.;/<
j W along the
aha/.t-
course of the




principal veins,
' and three shafts
_ may even be
', . 'made to cut the
same part of
‘ the vein at dif-
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ferent depths.
The most re-
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i shafts are used
for drainage
and extraction,
while the older
and more shal-
low ones serve
as footwags for
the ascent and
descent of the
miners. In some ‘of the ‘large Cornish mines, it is
not uncommon to sink two shafts near together, one
of large dimensions which is used for a drainage or
engine shaft, and'arsmaller one-for drawing ‘stuff only.
The shafts are usually rectangular in form; the whim
211 m
Fig





shaft, or that intended for the extraction of ores, is
commonly 6 feet by a, while the engine shaft may '
vary from 6 feet by 8, to 8 feet by 10, and even
larger. Fig. 1459 represents what is called a platt,
that is, a sort of cavity at the extremity of a level,
near the whim shaft, for the purpose of collecting
supplies of ore for filling the kibbles which raise it to
the surface- The sketch is supposed to be taken from
the side of the shaft; the men are boring in order to
place a shot for blasting so as to enlarge the platt.
The kibble shown is not of the regular size such as is
used for raising the ore, but a smaller one used for tem-
porary purposes such as this. The hole over which
the kibble hangs is a small sump or cavity about a foot
in depth, cut at the bottom of the shaftfor receiving
the drainage water. Fig. 1460, shows-a platt complete :
the sketch was ' ' -
taken in East
Wheal Crofty,
from the end of
the level which
opens into it. ’
This platt is
not at the bot-
tom of the shaft '/
as in the former '
case,.but at the
adit level. The
kibble is seen
hanging in the
shaft, which is
boarded off -
from the .platt to prevent accidents. When an
empty kibble comes opposite the door, the filler pulls
it in towards him with a long iron hook, and, having
landed it on the platt, fills it.
When a level opens to‘ the surface at the side of a
valley, it forms what is termed an aclit, or dag-level,
and most mines have at leastone for the purposes of
drainage. Where the mines are situated near the
deep ravines of mountainous countries, a succession
of adits may be driven. in, one below the other, so as
to prove’ the mine, and drain it, more or less, com-
pletely. Where a mine has been opened by sinking
down from thesurface, as is.‘ most usual, an adit is
commonly .begun from. the bottom of some neighbour-
ing valley, and is .driven towards the vein with a
slight inclination, to allow the water to flow through
it. Adits of enormous length have been formed in
some mining districts,j.so vas to traverse a number of
mines, and carry off .the water at the lowest prac-
ticable point. One of the most remarkable works of
this kind is the. Great Aelil, or principal level of
Cornwall, through which the waters of the numerous
mines in Gwennap and Redruth .are- discharged. Its
length, inclusive of its various branches, is about
2,600 fathoms, or nearly 30 miles. The greatest
length to which any branch appears to have been ex
tended from the adit mouth is at Cardrew Mine, and
measures. about 5% miles. The highest ground which



l/l/f


I’ l


" iM/ll/
.iit.has "penetrated is at Wheal Hope, where the adit
is 70 fathoms deep. This adit is 39 feet above the
MINE—MINING. ' , are
level‘ of the sea- at high water, in Itestronget Greek,
into which the waters discharged from it flow, its
mouth being near Nangiles, in a valley communicating
with the creek. ‘
The foregoing details will be assisted, as well as
illustrated, by the plan and section of a portion
of Dolcoath Mine, Figs. M61, 1462. In the upper
figure, or plan, the ground is supposed to be either
removed, or transparent, so as to show the under-
ground levels, adits, 85c. Numbers are attached to
the lines which represent the levels driven upon the
lodes, and these numbers give the respective depths
beneath the adit,1 so that if perpendicular lines were


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- ;_ I //,,,/,, (‘W
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rah .
Figs. 1461, 1462.
Gossan shaft is sunk perpendicularly; so that cutting
the plane of the lode somewhere near the 125 fathom
level, cross-cuts are made to communicate with it at
less depths from the north, and at greater depths from
the south, in order that the ores raised at these levels
may be brought to it,_ and lifted to the surface.
Several other cross-cuts will be observed on the plan,

(1) -In most of the Cornish mines the depths are reckoned from
that of the edit, and not from the actual surface of the country,
which often undulates considerably, so that a given level may be
100 fathoms beneath such surface at one place, and only 50
fathorns at another. By thus reckoning from beneath a well-known
level, such as that to which the water is pumped up, a more accu-
rate idea may be obtained of the depth of the workings than by
reckoning from the surface. The greatest depth that has been
attained by mining is in the now abandoned Kuttenberg Mine, in
Bohemia, which was 3,778 feet. Some of the shafts in the New-
castle coalfield are 1,800 feet deep. Most of the deep mines are in
Prussia, Norway, the Tyrol, Bohemia, fire; but their depth is
reckoned from the surface of the ground, which in mountainous
countries may be many thousand feet above the level of the sea.
Thus, at the Joachimsthal Mine, in Bohemia, the surface is 2,388
feet above the sea, and the depth 2,120 feet; so that the bottom of
this mine is actually above the sea level. The Valenciana Mine,
in Mexico, is 5,960 feet above the sea, and its deepest workings
are 4,274 feet above that level. The greatest depth below the sea
level is said to be a boring at Minden, 2,231 feet deep, of which
1,993 feet are below the level of the sea.



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let fall from this level upon such lines, they would cut
them at the various depths marked, such as 60, 70,
80, 100, or any other number of fathoms. It will be
i observed by the increase of the numbers marked on
levels to the southward, that the dip or underlie of
the lode must be in that direction; and further, that
lines representing equal depths are much closer to
each other in some places than in others, showing
that the lode approaches more towards the perpen-
dicular in those places than in others. In reality,
these lines are far more irregular than they are repre-
sented in the plan. Thus, while the engine shaft is
inclined with the dip or underlie of the main lode, the


I70


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21\'
PLAN AND SECTION OF PART OF THE MAIN LODE IN DOLCOATH MINE-
some of which are merely for the purpose of uniting
the various parts of the mine conveniently together,
while others act as channels for draining the waters,
so that they may be brought to the most convenient
place for pumping. Gross-cuts of this kind will be
seen between the North Entral ‘lode and the main
lode at the various depths of 410, 70, 80, 100, and
1.20 fathoms and the levels upon a‘ southern lode,
known as the Caum‘er, will be seen ' to cut" across or
abut upon those of the main lode, where— the two
lodes meet. ' i ' W
This plan, therefore, shows the mode in which the
levels on the lodes,‘ the shafts, the adits, and cross-
cuts occur. We now turn to the section, in which
the lines of levels and letters of reference correspond
with the plan. If we suppose the south side of the
main lode at Dolcoath, and consequently, as it under—
lies south, the upper or hanging wall to be removed,
we should have such a section of the workings as is
here represented. In this section, those portions
which have been cut for galleries in the levels, the
shafts, and where bunches or accumulations of ore
have been found, are left blank; and those parts in

which the rubbish 0f the workings (called [leads or
280
MIN Elf-MINING. I
Mile) ‘has ‘been thrown back, and so arrange'dthat thev
galleries or levels, and the shafts, should passfreely
through them, are represented as composed of broken,
fragments. The killas‘ or slate remains white, while
the graniteis dotted. We see that this main lode cuts-
into, granite in its eastern prolongation; and a tabular
piece of granite, ,-forming a projecting mass or vein
from that rock,‘ at a higher level, being cut by the
lode at-a short distance fromthe main mass of granite,
appears as 1 if separated entirely from it amid the slate.
The bunches. of _.ore.w_ill be observedv to have occurred
very. irregularly, and the places which they occupied,
in‘. a great measure-,vvfll [be seen filled upwith the
rubbish taken from the ‘non-productive workings of
the mine. Levels on the east have been driven into
thev granite in ‘search of bunches of ore, and in both
directions the search was abandoned.
It will bevseen that the sum}? or lowest part of the
engine shaft s forms the lowest part of the mine, as
already noticed. v'Atthe time when this plan was
made, theores were drawn up to the surface by four
shafts, by the three steam~whims; but the position
and number of the shafts varies with the state of the
mine, ‘so’ that». many shafts .may exist which are not
used for drawing ores or for pumping. This is now
the case with several shafts on the maintlode at Dol—
coath, including an old pumping-sh aft. As every shaft
hasv its namaland every level is known by‘its depth,
the @t'saiw of work ‘in any part of the mine is at
once comprehended by’all. A mine, in fact, resembles
a town, of which‘ the streets are known by names, and
the houses by numbers. _
The various cross-courses traversing the lode are
also marked and named; and although these, when
they heave the lode considerably, bar the progress of
the miner, or cause a great increase in the influx of
water into the mine, are injurious, at other times they
are highly useful,‘ by keeping out the water of a
neighbouring mine. In the latter case they are, consequence, preserved ‘uncut, as in Dolcoath Mine,
where the great cross-course on the east of the lode is
untouched, except at the adit-levels which traverse it.
This cross-course has cut through the lode, the con-
tinuation of which is worked in the adjoining mine of
Coo/s’s Kitchen, and heaved it, so that a line prolonged
from one would 'not strike the other; and it lately
kept out a body of water which had accumulated in
the old workings at Gook’s Kitchen. Such main
cross-courses, which frequently bound setts, and thus
often separate old mines, are carefully preserved, so
that the failure of one mine does not cause its waters-
topour in and deluge the other, beyond the power of
its engines to clear‘ it. In different parts of the same
mine, cross-courses are in part preserved, in order
to keepi’leut the water from the deeper levels, ‘when
this can ‘bedone conveniently. On the west of the
section the workings do not . reach a cross-course
beneath the étO—Dfathom level, though, from a shaft
having been sunk upon it, the workings which reach
it on the east. side are deeper. Cross-courses are
found extremely useful for driving adits upon, and as
they generally out the lode considerable angles, the

.work thus carried on exposes a good section of the
country, as it is termed, or ‘rocks on both sides, and
consequently of any lodes which may there occur.
‘The distances at which the levels have been driven
from each other are very irregular upon this lode,
except in. the lower workings, beneath those of 150
fathoms, which have been made more in accordance
with the modern practice of forming them 10 fathoms
from each other, as will be seen in the section, where
we 'find complete regularity in this respect from the
adit to the 90-fathom level. The workings beneath
that level have been driven for discovery, and at
greater distances, to save expense. On this cazmter
or contra lode, which is worked through Ham'ezfzf’s
lode up to the main lode, considerable expense was
incurred in driving levels, both in the .depth and
towards the eastward, in search of me, which was
unattended with success. These ‘heavy expenses on.
account of discovery can only be ‘profitably borne by
mines of a certain magnitude, which, throwing up
a fair general amount of ores, can afford to put aside
a certain proportion of the profits for discovery.
SECTION III.
The foregoing details refer to those countries where
the rocks explored exhibit no distinct traces of strati-
fication, and the metallic veins extend to unknown
depths. The mining districts of Cornwall, Saxony,
andMexico are examples. In countries where the
rocks are stratified, mining operations necessarily
assume a different character; the vein, instead of
extending throughout the rock, as in the former case,
is chiefly confined to rocks of a certain class, the in—
termediate strata being unproductive. Thus the car—
boniferous limestone of North Wales, Derbyshire,
and the north of England, is rich in lead, while the
superincumbent grits and shales are unproductive
rocks. All, therefore, that is necessary is to work into
the limestone, for which purpose the mountainous
character of the countries indicated is highly favour-
able. Some point is selected in a valley or ravine at
the outcrop of the strata, and from thence a level,
MINING IN Srna'rrrrnn Rocks.



Fig. 1463,
L, Fig. 1463, is driven in a rock which is known to he
favourable to the mineral deposit, and where practi-
cable the level is-driven into the vein itself, which
affords effectual means for exploration and faci-
lities forgetting out the ore. . Should the ore not be
discovered in driving the level, cross-cuts are made in _
‘one of the adjoining strata. When bunches of ore
are found, BXCiWfit-iOIIS are made in them upwards and
downwards, so as to lay them open for convenient ex-
traction. ' If 'the' ore extend. up towards the surface,
MIN Fiflh'llNIN Gr.
281‘
another level, L’, maybe driven from the ‘rises, 7*, above
the first level, and similar operations be carried on in
any productive stratum that may occur. When the
vein has thus been laid open for working, the masses
of ore are got out either by the pick or by blasting,
and the stuff is made to fall into the lower level,
whence it is conveyed in trams to the entrance. The‘
principal level is driven, if possible, upon the lowest
productive stratum, so as to serve for drainage and
extraction. The work is thus carried on by a system
of rises, unless, indeed, a discovery should be made
of ore below the principal level, in which case it is
got at either by means of another day level or by
means of winzes, 20. When, however, the level has
been carried to a considerable distance from its mouth,-
a shaft may be required, not only for the purposes of
ventilation, but also for working the mine.
SncTIoN IV. MINING TooLs AND Pnocnssns.
The tools employed by the miner in excavating the
vein or rock are very simple; the pic/c, a, Fig. 14164,
the wedge or yard, and the shovel, d, being used for
excavating "soft ground ; and the borer or jumper, (Z,
with a hammer, e for striking it, when the rock is so
hard as to require the use of gunpowder. The pick,
a, resembles a common pickaxe, but smaller; the iron
head is sharp and pointed at one end, and very short
and hammer-shaped at the other; this tool is much
used both in working in the rock and in breaking
down ore. The wedge or gad is of wrought-iron, and
often with curved sides: it is used for driving into
crevices of rocks or into small openings made with the
pick. The shovel is pointed, to allow it to penetrate
among the coarse hard fragments of mine rubbish,
and its handle is somewhat bent. The borer or
(Z
a b a


fig
jumper, (Z, is an iron rod or bar about 2 feet long,
steeled and formed into a flat sharp edge at the end:
it is driven into the rock by one man with the ham-
mer, a, while another man turns it after every blow,
so as to expose fresh surfaces of the rock to the edge.
The pulverised matter thus produced in the hole is
drawn up from time to time with a scraper, g, and
when sufficiently deep, the hole is charged with
powder, and the needle or nail, j; a small taper rod of
copper, is inserted so as to reach the bottom of the hole
which is next to be tamped or filled up with some
substance, such as dry sand or tough clay, which will-
firmly hold the powder and prevent the explosion
from taking effect by way of the hole. Small quan-
tities of this substance are introduced at a time, and
rammed firmly down by means of the warping-bar, it,
the divided stem of ‘
which allows the nee-
dle to pass up between
the prongs. The tamp- a ,
ing-bar is held firmly ‘if, -
by one man and struck f i
by another with the
hammer, -- a danger-
ous operation, and still
more so when the
tamping-bar was of f
iron, instead of being,
as it now is, faced or q,"
tipped with copper.
Fig. 1465 represents
two men at work in
an end. One man is .
getting a hole ready for tamping, while another is
pounding some stone for tamping upon another stone
held between his knees. When the hole is filled the
nail is withdrawn by putting a bar through its eye
and striking it upwards. In this way a‘ small vent-
hole is left for firing the shot, as the charge of powder
is called. A train of gunpowder is next laid and fired
by a swift or slow match, which may be a long green
‘ a :¢=___>Ex
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rush with the pith removed and then filled with powder,
or merely a piece
6 f 5/ if 7’ ‘ of brown paper
smeared with
OI grease: the mi-
ners then with-
draw until the
J explosion is over.
When the rock
is wet, a tin car-
tridge, z', is used.
A safety - fuse,
now in use' in
Cornwall, has
been the means
of saving life to
a large amount.
This fuse is made
by machinery:
string is coiled
so as to form a
cylinder, which receives the powder specially manu-
factured for the purpose, and by a continuous opera~
tion, enormous lengths of the fuse are formed. In
practice the charge of powder is placed in the hole,
and the required length of fuse carried down to it.
The hole is then tamped, and the fuse carried out at
the top of the hole. When everything is ready, the
Q g i

_l r‘
1464.
qésczmm
282
MINE—MININ G.
firemen enter the mine and extinguish the fires.
miner lights the end of the fuse, and as this burns
slowly he can withdraw safely before the explosion
takes place. Blasting cartridges are also in use: an
elastic substance is placed in the upper part of each
cartridge to prevent the possibility of an explosion in
tamping: the safety-fuse is united with the cartridge.
When used in wet ground or under water the cartridge
and fuse are coated with pitch or gutta percha.
According to Overman,1 “ If ' holes ‘for blasting
cannot. we'll-‘be drilled they can be formed by acids.
Pyrites. maybe penetrated by nitric or muriatic acid;
also? native ‘metals, such as copper, limestone, and
magnetic may ‘be ‘dissolved by any acid; the
muriatie however, "the most generally used. In
thiscasje'we cannot sink any other form of hole than
, "'a'vertiealone. The manipulation is easily performed
' byfsjetting a "tube vertically upon the rock, and
. its top witl'r a funnel and apparatus, so as
i' to? let inthe acid drop drop. If the pipe is close
fitting to the rock, and the acidvpoured in very slowly,
the hole not be much larger than the glass pipe.
The tube must deseend'with the bottom of the hole,
and bev alWaysclQSQ to it. This operation works very
slowly, but in pyrites, or compact magnetic iron ore,
which cannot be penetrated by steel tools, it is a
‘useful method of preparing a hole for blasting.”
AtRammelsberg, in the Hartz, on account of the
hardness of the rock, the ore is got out by the direct
action of fire. The substances in the workable mass
are copper and iron pyrites with galena accompanied
by quartz, carbonate of lime, compact sulphate of
baryta, and sometimes grey copper ore, sulphuret'of
zinc and arsenical pyrites. The general system is as
follows :--An advance is made towards the deposits
of ore at different levels by transverse galleries pro-
ceeding from the shaft and terminating at the wall of
. the mass. Large vaults are formed by means of fire
in the heart of the ore. The vault is, however, first
opened by blasting, after which it is enlarged by fire;
for which purpose billets of firewood are piled up and
made to rest against'the ore, so that when set on fire
the flame may play against the mineral mass which is
to be detached. vThe faggot-s are distributed in the
vaults of the different levels during the week, and are
fired on Saturday, the upper vaults first,“ and when
one fire is fairly kindled, thenext below it is lighted.
The efiect is ‘said to be exceedingly grand. Soon
after the flame has touched the ore, a strong odour of
sulphur, and sometimes of‘ arsenic, is disengaged,
and loud detonations are heard, accompanied by the
fall of flakes of ore. The flame assumes various
colours, arising from the volatilization of sulphur, zinc,
arsenic, &c.-, and the ore is broughtv into that state in
i which it can be easily detached by long iron forks. The
combustion goes on till Monday morning, when the
On
Tuesday the people are busy in detaching the ores,
sorting them and taking them out, and the remainder
of the: week is employed in building up fresh faggots.
In proportion as the roof is scooped out in this 'way,

(1) Treatise on Metallurgy, 8vo. New York, 1852.

the floor is raised by means of terraces formed from
the rubbish.
Snc'rion V. DRAINAGE, VENTILATION, TIMBERING,
&c.
We have hitherto referred only incidentally to the
important subjects of drainage, ventilation, timbering,
and the best means of extracting ore and rubbish.
Unless mines are worked by means of day-levels or
adits, and even then if the workings are conducted
below the principal level, water filters rapidly into
the mine, and the more so if the rock is porous, or
if this be compact the mineral vein itself is likely
to be porous. The waters which pour into the
workings may be got rid of by means of adits, as
already noticed; but should the nature of the country
prevent their adoption, mechanical power must be
resorted to, as indeed it must be wherever the work-
ings are below the adit level. The simplest apparatus
used for the purpose of drainage is the lzorse-zoizz'm,
whims-cw, or give, which is used not only to raise the
water but also the stuff got out in sinking. It con-
sists of an upright shaft, carrying a large drum
and projecting arms or levers, to which horses are
attached for turning it round. Round the. drum is
coiled a rope, the two ends of which, after being
guided over pulleys, pass into the pit : a large bucket,
kibble, or corve is attached to each end,- so that while
the rope is winding or unwinding on the drum, one
full bucket‘is ascending, while the other, the empty
one, is descending the pit. Where mines are not very
deep, or where the quantity of water to be raised is
trifling, this apparatus is of use, but it cannot be
applied on a large scale. Where the locality is
favourable for the purpose, water power is admirably
adapted to the requirements of a mine. The German
miners took advantage of this steady and economical
first mover at an early period, and applied it with
remarkable skill, as they still continue to do. In
England, the great abundance of coal has led to the
steam-engine being chiefly employed in draining
mines, and also in raising the ore, &c.; although,
where circumstances have been favourable, water
power has also been employed. In the application of
water power, the nearest, stream is conducted into an
‘artificial channel or leaf, and conveyed into the
mine so as to have a suificient fall to turn an overshot
wheel; the water which passes off from the tail of
this wheel is made to do duty again upon another
wheel at a lower level; a third wheel, still lower,
may also be set in motion by the waste waters of the
second and first; and so on as long as a sufficient fall
can be produced. The wheels vary from 10 or 12 feet
in diameter to more than 50, and from 2 or 3 to 6 or
7 feet in breast. Some of the largest are upwards of
100 horse-power.
The pumps used in mines do not act on the
principle of atmospheric pressure, as in the household
pump, but- they are simply Zz'fi‘s or columns, some-
times 20 vor 30 fathoms in height, and 10, 12, or
more inches in diameter; at the foot of each column
is acistern, into which the water of the column next
MINE—MINING.
283
below is discharged. The whole column of pumps is
worked by a single piston—rod passing down the
middle and communicating with each column by a
rod attached to its side. A reciprocating motion is
imparted to the main pump-rod, by means of a crank
on the axleof the, water-wheel attached to one end of
a horizontal rod, the other end'of which is fixed to a
005, or upright post, movable on a centre and braced
to a horizontal piece framed into it at the bottom,
the further end of which is connected with the pump-
rod, In this way the rotatory motion of the water-
wheel is converted into a steady reciprocating motion
when communicated to the pump-rod. It is neces--'
sary, however, to counterbalance the weight of the
pumperod, which is done by means of a large ‘box
filled with stones, iron, &c., attached to the opposite
end of the balance-bob. The‘pumps are of iron, and
allow the columns to extend to a great depth without
leaking or danger of bursting. In some of the Ger-
man mines, where the supply of water is limited and
a considerable fall can be obtained, the water pressure
engine is used.
Some of our deepest and most extensive mines owe
their great depth and extent to. the progressive im-
provements which have been made in the steam-
engine. In Cornwall, where the cost of carriage
renders fuel comparatively high priced, improvements
have been made in the engines, chiefly with reference
to economy in fuel,1 and the efficiency of a steam-
engine for mining purposes is estimated by the
amount of work performed with reference to the
consumption of a given quantity of coal. This is
termed the duty of the engine, and it is expressed by
the number of millions of pounds raised 1 foot high
by a bushel or 941 lbs. of Welsh coal. In a pumping-
engine, the data for this calculation‘ are the quantity
of water discharged from the pumps in a given time,
and the quantity of coal consumed by the engine in
the same period. The progressive improvement of
the duty of steam-engines will be seen from the
following statement :—
, In 1769, the old atmospheric engine, by lbs.
consuming a bushel , of
coals, raised
,, 1772, as improved by Smeaton .... ..
From 1778 }the steam-engine as improved
5,500,000 1 ft. high.
9,500,000 ,,
to 1815, by Watt 20,000,000 ,,
In 1820, as improved by the Cornish
Engineers........................ 28,000,000 ,,
,, 1826, ,, ,, 30,000,000 ,,
,, 1827, ,, ,, 32,000,000 ,,
,, 1828, ,, ,, 37,000,000 ,,
,, 1829, ,, ,, 41,000,000 ,
,, 1830, ,, ,, 43,350,000 ,,
,, 1839, ,, ,, 54,000,000 ,,
,, 1850, ,, ,, 60,000,000 ,,
These numbers indicate only the average duty:
many engines greatly exceed the last-named result;

(I) Some idea of the extent to which steam-power is employed
in Cornwall, may be formed from the following brief statement of
the quantity of coals consumed per month at a few of the principal
mines :--
Bushels of 94 lbs.
Fowey Consols, 1835 .................. .. 101,246
Godolphin, 1839 129,801
Fowey Consols, 1840 203,699
United Mines, 84,862

as for example, at the Consolidated Mines in 1827,
the highest duty was 67,000,000; at Fowey Consols
in 1834.‘, it was 97,000,000 ; and at the United Mines
in 1M2, it was 108,000,000. Still greater improve-
ments may be expected; for it appears from the ex-
periments noticed in our article FUEL, vol. i. p. 7 25,
that the duty falls very far short of the actual force
generated.
The steam~engine employed in pumping, is erected
close to what is called the engine-shaft; one end of
the beam, to which the pump-rod is attached, is
situated over the centre of the shaft; the pump-rod
is counterbalanced by a balance-bob, as in Fig. 1471,
so that'the power of the engine is not wasted in
lifting the pump-rod, which is very ponderons, but is
employed in, raising the column of water in the pumps.
The diameter ‘of the cylinders used in the construc-
tion of. these engines, varies from 400 to 90 inches;
the latter being equivalent to 300 horse-power.
High-pressure steam of 400 or 501bs.‘ to the square
inch is used expansive-1y; the communication with
the boiler being cutoff at 11th or g-th of the stroke; a
short interval is also allowed between each stroke for
the perfect condensation of the steam, and the boiler
and cylinder are carefully cased in. so as to prevent


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INTERIOR 05." A SHAFT.
Fig. 1466.
loss of heat by radiation. Fig. 1466, shows the inte-
rior of a Cornish shaft, with the engine-pumps, ladders,
and kibbles; the last ascending and descending. In
general, the portien of the shaft where the kib bles
pass is boarded off from the rest to prevent accidents
est.
MINE—MINING."
by any portion of their contents falling out, or from
their swinging by striking against the sides. The
entrance to a level is shown on the left.
Some ~idea of the elaborate and apparently complex
arrangements of a shaft is better conveyed by Figs.
1467, M68, which represent the same shaft under
different points of view, one at right angles to the
other. The methods of supporting the walls are
shown by the timbers H’ .' 'the miners ascend and
it
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Figs. 1467, 1468.
It is evidently necessary to the permanency of a
mine, that in excavating the enormous quantities of
ore and rubbish which are being constantly brought
up, the roof be prevented from falling in and involving
everything in ruin. Support may be given to the roof
by means of pillars left in the vein, the poorer por-
(_ tions being selected






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‘pl a a; or by walhng either
a i'__ '\ I 1"‘. f\ ‘I’ I u
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‘wimp, W \ : ‘i the friable nature
it’: .rivil-ilyyagllh' of the rock, a shaft
lllillyn- ” ‘JV require support,
afoul‘ pieces of
llllllllitl strong timber are
., .
framed into each
other, and a num-
ber of such frames
being fixed at in-
tervals of about
‘in feet apart, the
_ I 7 intermediate spaces
are filled up ‘with? boards driven between the frames-
and the rock. Levels are supported by three
pieces of timber arranged in the form of a doorway,
rather narrower above than below, and framed toge-
ther at the top; the ground between every two door—
ways being supported by planking. The large open
excavations or ‘gunnies, from which ore has been
removed, are'kept open by means of strong pieces of





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i i i ‘iii? \ - -‘ ‘~ '1 ' ‘1;. ‘...="l,b,-“= 'l" "grill
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descend by the ladders‘! l’: rr are the pumps, the
pistons of which are worked by the rod r r, the con-
nexion with the piston rod being made as shown at
it‘: each pump discharges into a cistern 0, by a shoot
8, and into this cistern the lower extremity of the
barrel of the pump next above dips. w w’ are corve
ways by which the ore, &c. is raised in buckets B.
This shaft is sunk in the line of the vein, the rock
enclosing it being indicated at the sides of each figure.


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iitlllll'
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VERTICAL SECTIONS OF THE SHA'FT OF A MINE IN GERMANY.
timber placed, as shown in Fig. 1469,1 so as to press
against the two walls of the vein, which are thus
prevented: from closing in. These gunnies are useful
receptacles for the deads and cattle, or rubbish which
are constantly accumulating from the workings car-
ried on in the rock or unproductive parts of the vein.
A gunny is prepared for the reception of the rubbish,
by placing in the backs of the levels strong timbers,
upon which boards are laid so as to form a close
covering or stall, and ' the deads and attle being
thrown upon it until the space above has been filled
up. Walls of‘ the vein are in this way supported,
while much useless material is got rid of. There
still, however, remains a large quantity of rubbish,
which cannot thus be provided for, and it is sent up
the shaft to swell the waste heaps which form a
conspicuous feature at the surface of every mine.
The extraction of an extensive mine is so great, that
the quantity of ore raised is seldom more than ith or
art, and even less, of the mass of stuff which is raised
to the surface. At the Consolidated Mines in Corn-
wall, some years ago, the daily extraction was about
200 tons, a- large proportion of which was raised from
a depth varying from 200 to nearly 300 fathoms. The
timber used in the mines of Cornwall and Devon is
Norwegian pine, which is admitted free of duty for
mining purposes; and so great is the quantity in
actual. use, that, according to a calculation some years
ago, 140 square miles of Norwegian forest would be
required to afford a supply for these mines.
As there are no noxious or inflammable gases gene-
rated in these mines, the ventilation is much more
simple than that required for a coal-mine. [See Conn]

(I) This figure represents a. man at work in a pitch in the back
of the level} The two men below are driving an end.
MINE—MIN IN G.
285
It is carried on simply by communication from shaft
to shaft iby'the different levels, and from level to level
by means of the winzes. When these communications
are properly made, currents set in in different direc-
tions, varying according to the temperature at the
surface and the increasing temperature at different
depths. '
The temperature of mines opens an interesting
question on the subject of terrestrial heat. At no
great distance below the surface, but varying in differ~
ent places in some degree according to the nature of
the rock, the effects of atmospheric temperature begin
to cease. According to the experiments made in the
caves of the Observatory at Paris, the annual or diurnal
variation of temperature ceases at the depth of 25
feet. In various Prussian mining establishments the
same result has been obtained at depths ranging from
27 to 63 feet. In the neighbourhood of Edinburgh,
according to Forbes, the effects of atmospheric tem-
perature are no longer appreciable at 55 feet depth
in trap rock ; at 65 feet in loose sand, and at 96 feet
in compact sandstone. Below the point where exter-
nal causes of heat‘ cease to operate, it has been found,
from abundant observations in different parts of the
world, that a progressive elevation of temperature
takes place from some internal cause proportionably
as the depth is increased. The rate of increase differs
in different localities in consequence of difference in
the nature of the soil and the rock, and from the
varying elevation of the sites. According to a series
of observations by Mr. Henwood the following results
were obtained by taking the temperature of the water
as it oozed from the rock, before it was influenced by
the temperature of the levels :—
Depth. Temperature.
At St. Just ....... .. 150 feet 51°
,, ....... .. 420 ,, .... .. 56
,, ....... .. 768 ,, .... .. 62
At Redruth ....... .. 198 ,, .... .. 52
_,, ....... .. 456 ,, .... .. 58
,, ....... .. 780 ,, .... .. 70
,, ....... ..1,062 ,, .... .. 86
,, ....... ..l,470 ,, .... .. 89
Similar results have been obtained in the mines of
Saxony and'elsewhere. The rapid increase of tem-
perature at great depths considerably increases the
difficulties of mining. ‘ '
Snc'rron VI. ECONOMY or MINES.
With respect to the internal economy of mines, Mr.
John Taylor, after remarking on the mechanical im-
provements which have taken place in the ‘art of
mining, says :——“ Important as the improvements are
which we have contemplated in the instruments which
the progress of physical science has placed in our
hands, those which relate to the government of large
bodies of workmen, to the inducement to active en-
terprise on the part of the labouring miners, to the
removal of dificulties in their way, or of placing them
in circumstances most favourable to effective exertion,
are even more important, and to this may be added
the judicious application 'of those very inventions
which have been noticed. It must be recollected,
that, after all, the great expenditure in mining is for

manual labour, and that we have no. means as yet
devised for penetrating the rocks which contain
mineral treasures but those afforded by the patient
and unremitting labour of a great number of men.
The regulation, therefore, of this force, and its due
application, is after all more important to the success
of mines than even the most ingenious mechanical
expedients.”






$19. 1470.
THE CORNISH MINER.
The underground work of Cornwall, and most other
districts, is of two distinct kinds; dead-work, also
called tut-work, or that which is carried on in the
rock, vein, or deposit, for the purpose of discovery;
and productive labour, called tribute, which consists
in the breaking down and extraction of the ore. Each
kind of work is performed under a series of contracts,
which unite for the time the interests of the miner-
and his employer, and lead to a skilful division of*
labour. The practical direction of the works is con-
fided to agents named captains, who are generally
selected from the most intelligent workTmen.~‘_'I'n the
larger mines their duties are divided. .A' captain of
the greatest experience usually governs the rest, and
in conjunction with, and under the advice of, one of
the partners or the principal manager, attends- to all
the business of the concern; while the departments
of account, of the construction and care: of- engines,-
of the purchase of the various articles used, of the ore-
dressing, &c., are superintended by persons-‘appointed
by the manager and principal captain.‘ The captains
under the chief have different‘ duties vassigned them :
those employed underground se'e Lthatgthe work is
there conducted properly; while ‘the grass-‘captains
superintend the 'work- on the surface, such as the
dressing of ore, &c., which is done‘ in ‘the dell, or
upper part of the mine. Engmeers‘ are also appointed,
and to them is confided the care of the various engines
and machinery.
The persons working under the captains are divided
into trite/fem, tat-workmen, and Zaécurers. Tribnters
are men who agree to work a portion of a lode for
a given time in the best manner they can, receiving
as remuneration a certain portion of the value of the
ores raised, as may be agreed upon. This portion
necessarily varies according to the value of the part
286
MINE~MININ G.
of the lode which is likely to be worked in the given
time, usually one or two months. Thus, if the lode
be rich, and is likely to continue so, a smaller portion
of the value of the total quantity of the ores raised
by the miners, taking the pitch or lode to be worked
in the given time, is agreed upon, than when the'lode
is somewhat poor and may continue so. The mode
in which the agreement is made is as’ follows :-'-—
Upon the setting-days, as these agreementadays are
termed, the miners assemble before the counting-
houses, and meet the captain's, who have previously
examined the various parts of ‘the mine, and deter-
mined what they consider fairltierms upon which the
various pitches should beset or: granted. The men,
on the other hand, have also edine to an estimate of
the terms they will offer to execute the work, taking
all the usual chances. The chief captain now puts
up the various pitches to auction, the biddings being
downward. The‘ ‘captain generally names ‘ a price
above that'which ought to vbe given, and the miners
bid downwards against each other, if .theyplease, until
the fair price‘ is agreed upon, which is generally nearly
understood. beforehand,‘as all parties are ‘fairly aware
of what it ought to be. It may happen, indeed, that
the miners at work on the spot, just before the setting-
day, have discovered appearances which lead them to
think that they may take the pitch on apparently low
terms, so that they may gain largely by breaking an
amount of ores which the captains may ,‘not consider
probable; but this occurs rarely. The pitches are
commonly taken by a number of men proportioned to
the work to be executed, but though they often vary
from 2 to 12, it is usually contrived that there shall
be at least 2 for each spell or core of 8 hours, the
usual division of the spells. This partnership is gene-
rally termed a pair of men, whatever the number may
be, and one commonly acts at the setting-days as a
bidder for the rest. When no one is disposed to bid
lower, the captain flings a pebble to the tater, as he
is styled, and he is proclaimed, and his bargain en-
tered. It is seldom that the captain fails to find
a taker at a fair price, but should he do so, the work
is referred to some future setting-day. As soon as
the pair is chosen, they are entitled to an advance of
money for subsistence, and hence called ’sz'st-m0ney,
until the period of their taking is- completed. The
setting-day is a holiday at the mine, and generally
occurs every two months. Before proceeding to the
business of bidding, the rules are read, and fines
attached for breach of regulations.
By obtaining a certain sum in the pound for the
ores when sold, the tributers are interested in sending
up as much ore to the surface as they can during
their occupations in the various pitches, and hence
their ‘interests become those of the mine generally.
If a pitch should turn out better than was expected,
they may-gain considerably; but should it become
poorer, ‘they'suffer- loss in proportion. The tributers
pay for their coals, candles, and gunpowder; for ‘the
use of the machinery by’which the ore is raised-to the
surface; and the wages of those who wash and‘ pre-
pare the ores for" sale.
It is not known when this system of war/{stay on
tribute‘ was first introduced. Mr. John Taylor remarks,
on the working of this system, that “ the mine owners,
having by their capital, and the skill of their agents,
discovered the ore, formed approaches to it, drained
off the water, and ventilated the places for working,
admit co-adventurers for a time, whose interest it is
not only to search out every piece of ore that can be
profitably worked, but so to detach it from the matter
with which it is mixed, as to incur the least possible
expense in after-processes. The payments they make
cause them to look with a jealous eye on all cost
incurred by others through whose hands the ores
may pass, and thus to tend to a general economy,
and perhaps, above all, discoveries are much extended
by speculation among the men, who risk their labour
only while they bring into play the judgment which
the habit of constant observation enables them to
form.”
Tat-workmen are those who execute work by the
piece, generally calculated by the fathom. In this
manner shafts are sunk, adits driven, and the labour
usually performed in those parts of the mines which
do not produce ores, executed. Tut-work is also
employed upon the lode itself, though from the ad-
vantages generally considered to arise from the tribute‘
system, the latter is employed as much as possible in
mines at full work. I '
Day Zabomvars~ are generally employed on the surface,
indres'sing' ores, and in occupations of the like kind,
though in some mines day-labour is also usedrunder-
ground. A large proportion of the surface labourers-
consists of women and girls.
The comfort of those employed in the mines has
of late received far more attention than formerly, and
the places where the women and girls pound or pick
the ores on the surface, are now nearly always de-
fended from the weather. Barracks are provided for
the miners to change their underground clothes, and
arrangements are, in some cases, made for drying those
which have become wet during work. The miners
are liable, from their occupations, to many accidents
and diseases, and it is, therefore, usual to provide
medical attendance for them, out of a fund raised by
the miners themselves. In the deep mines they suffer
much from climbing the ladders to the surface, as also
from the great changes of temperature experienced
in winter, when, after working several hours under-
ground, in a temperature from 70° to 90°, they walk
to their homes in the. cold. -
SOextenSiVe- are some mines, that it frequently
requires an hour to reach the surface, after work is
done.1 The ascent.’ and descent is by ladders, each
fifty feet long; which were formerly, and still are in'
some places, perpendicular to the sides of the mine;
but as‘ the mines. havebeen worked deeper, the ladders
have been ‘shortened to half that length, and. placed"


as 'slopin'gly as: possibly, to ease the miner, whose
weight is thus rendered more dependent-on his feet
(I) The'workings of the‘Consolidated Mines alone extend sixty;
p three mi1esund6Ig1'0und,~- or 55,000 fathoms. I
MINE—MINING.
287
than on his hands. At the foot of each ladder is a
platform, called a soZZar, with an opening, or manhole,
leading to the next ladder beneath. Considerable
attention has been paid in Cornwall to the practi-
cability of providing machinery by which the labour of
climbing the ladders may be avoided—a plan which
has been successfully adopted in the deep mines of
the Hartz. At the Tresavean, the deepest mine in
Cornwall, which is worked at a depth of upward of
300 fathoms,1 a mam-engine, as it is called, has been
erected for raising or lowering the miners, to the depth
of 240 fathoms. We will endeavour to explain the
principle of this machine. Conceive two rods, A and
B, descending the whole length of the shaft, and that
from each rod project horizontal stages, or platforms,
at distances of 2 fathoms apart, the whole way down.
We will call these stages, respectively, A1, A2, AS,
All, &c. and B1, B2, B3, 134:, 850. Now, suppose each
rod to have a reciprocating motion up and down,
through 2 fathoms, and that as one rod is moving
upwards the other is moving downwards. When the
rods are at rest, the respective stages, A1, B1, A2,
B2, &c. coincide. If a man place himself in the stage,
A1, and remain there, it is evident that he will be
moved up and down through 6 feet, and nothing,
more; but if when, by the downward motion of the
rod A, the stage A1 be brought opposite B2, he step
from Alto B2, he will have descended through 6 feet;
and if the rods be so arranged, that when A is at the
top of its motion, A is at the bottom, the man now on
B2 will be brought opposite A3, and he'steps upon
it. The next reciprocation will bring A3 opposite 134:,
and he steps upon that, and thus, upon each shifting
of the rods, he is able, with very little exertion, to
descend through 6 feet; and what is of even more
importance to him, he can ascend without fatigue,
and, after some experience, without danger, by similar
means, by standing on the lowest step, and when the
rod has risen 6 feet, stepping upon the next higher





taken from a sketch by Mr. Charles Cochrane, only
one rod is represented, the second rod being replaced
by fixed steps on the opposite wall of the shaft. As
the rod descends, it brings the stage, A1, opposite
the fixed stage, B2; the man steps upon this, waits a
moment, when the ascent of the rod brings A2 oppo-
site B2, the man steps upon A2, which lowers him
to B3, upon which he steps; and in this way he

(1) Dolcoath Mine is more than 210 fathoms below the adit-level,
which is 30 or more fathoms below some parts of the surface. The
main shaft of the Fowey Consols is about the same depth.

descends as easily, but not so quickly, as in the former
case. The rod derives its motion from a crank
attached to an overshot water—wheel. The crank is
supported on a friction roller, at B, and moves with
a balance-bob, at B. The platforms or stages are so
arranged as to coincide with the dead points of the
crank, so that there is a slight pause at each coinci-
dence of the stages. It is not the least of the many
recommendations of this simple but admirable arrange-
ment, that the rods may serve as pump-rods for driving
a set of pumps at the bottom of the pit, or a system of
pumps at different levels; or for forcing fresh air into
the mine and drawing out the foul. Each rod, A or
B, when of iron, may be double, like a ladder, with
the stages fixed between the pair. There are also
guides for maintaining the rods in their vertical
position.
In coal pits, or coal and iron pits, the men are
lowered down and raised in a rectangular iron frame,
called acage. Two causes of accident pertain to this
method ;—one is the breaking of the rope, or chain,
by which the men are thrown to the bottom, and
killed; the other arises from the overwz'rzclz'rzg of the
cage, or drawing it over the framing at the pit’s mouth,
in consequence of the carelessness of the engine-man
omitting to stop the engine in time. The result is
usually fatal, as the poor miners are thrown down the
pit. In the Great Exhibition was a safety bucket,
invented by Mr. Robert Blee, of Redruth, and a safety
cage, by Messrs. White and Grant, of Glasgow. In-
ventions of this kind depend upon some such arrange-
ment as the following :--Two pairs of eccentrics are
keyed on the ends of two parallel shafts, extending
across the top of the cage from side to side: the edges
of the eccentrics are toothed, and when the cage is
ascending or descending, the eccentrics are free of the
vertical wooden guides or rails which steady the cage
in its motion up and down the pit. Should the rope
slacken or break, two volute springs instantly bring
round the thick sides of the eccentrics to bear against
the guides, and hold the cage securely. To prevent
overwinding, the holdfast which connects the rope to
the cage is secured by a curved bolt, which is kept in
its place by a strong spring: the bolt moves on a
fulcrum, and is continued beyond the holdfast, as a
lever: across the framing at the mouth of the pit is a
bar, so arranged that when the lever comes in contact
with it, the bolt is instantly disengaged, leaving the
cage fixed by the action of the eccentrics, while the
rope alone is drawn up over the pulley. In Mr. Blee’s
contrivance the catches allow the cage or bucket to
move freely, so long as there is a vertical strain on
them; but should this cease, in consequence of the
breaking of the rope, the catches are liberated, and
secured upon the iron staves of the ladders placed on
either side of the shaft.
We cannot conclude this notice without referring
to the extraordinary situation of some of the Cornish
mines, especially the Botallack mine, represented in
a steel engraving, and of which Fig. 1472 gives
another view. In the Saint Just district, near the
Land’s End, the directions of the veins and the dis-
288
MINE—MIN IN G—MINERALOGY .
tribution of the ores direct many- of ' the mining
operations towards the sea. Several of the mines
are" worked to some extent beneath the bed of the
Atlantic, and the breaking of its waves is distinctly
audible to the miner whilst at work. In Little
Bounds, Botallack, and Wheal Cook, the ‘miners
actually followed ‘the ore upwards to the sea; vbut
the openings made were‘ very small, and the rock
being extremely hard, a covering of wood and cement
in the two former, and a small plug in the latter mine,-

7 Fig. 1472.
over the rocky bottom. But when standing beneath '-
the base of ~the cliff, and in” that‘ part of the mine
where but ninemfee't‘ of rock stood between us ‘and the
ocean, the heavy roll of the larger boulders-the cease-
less grinding of the pebbles, the fierce thundering of
the billows, with ‘the crackling and‘boiling as they
rebounded, placed a tempest in its most appalling
form too vividly before me to be ever forgotten.
‘More than once, doubting the protection of our rocky
shield, we retreated in affright; and it was only after
repeated trials that we had confidence to pursue our
investigations.” 1
MINERAL wx'rnns. See WATER.

sufliced to exclude the water. “ In all-these, and in
Wheal, Edward, ~ and Levant,” says Mr. Henwood,
“I have heardthe dashing of the billows and the
‘grating of the shingle overhead, even in calm weather.
I ‘was once, however, underground in Wheal Cock
during a storm. At‘the extremity of the level sea-
ward, some eighty or- one hundred fathoms from the
shore, little could be heard of its effects, except at
intervals, when the reflux of some unusually large
‘wave projected a pebble outward, bounding and rolling
‘TIM—M a}; ' 1'
; .ga... “\AM
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EXTERIOR WORKS AT BOTALLACK MINE.
MINERALOGY is that branch of Natural History
in which mineral substances are classified and distin-
guished, their uses made known, and their modes of
occurrence in the earth pointed out. A proper know-
ledge of minerals cannot be acquired without a
knowledge of their chemical composition as well as
their external or physical properties. - There are sub-
stances whichare similar in composition but different
in physical properties; and there are also bodies
which are externally alike, but of very different
chemical constitution. In the strictest sense, how-
ever, a mineral species is a natural inorganic body,
with a definite composition, and a regular determinate

(1) In thepreparation of this article we have consulted avariety
.of works, among which may be mentioned Mr. Henwood’s papers
in the Transactions of the Geological Society of Cornwall, Pro-
fessor Ansted’s Geology, the article Mining in the Penny Cyclo-
padia, Regnault’s Chimie, Ville-Posse sur la Richesse Minérale,
and the Report on the Geology of Cornwall by Sir H. de la Bcche,

Among our illustrations, Figs. 1458, 1459, 1460, 1465, ‘are from
sketches taken by Mr. F. B. Miller, of King’s College; _Figs._1456,
1457, 1464, 1466, 1470, are from Mr. Cyrus Redding’s Illustrated
Itinerary of Cornwall, of which the original wood engravings
have been placed at our disposal: Figs. 1461, 1462 are reduced '
from Sir H. de la Beche’s Report.

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MINERALOGY.
289
form or series of forms. Hence we ought to exclude
from the study of n1ineralogy,——the salts of the
chemist, which are artificial ,- air and water, and the
inorganic secretions of plants and animals, which have
no regular determinate form. Most mineral systems,
however, include coal, amber, and mineral resins; as
also certain am'orphous substances of no precise form

or chemical composition, such as some kinds of clay.
Aggregates of simple minerals, such as rocks, belong
properly to Geology.
Minerals have been classified in varioiis ways, but
perhaps the most rational method is that which is
based upon their chemical composition. The follow
ing classification is by M. Dufrénoy z‘—
Flns'r CLAss—Sz'mple substances, eueiz being one of Me essential principles ry” compound minerals.
Electro-negative bodies; never acting as a base with the bodies of other classes, and always forming a
constituent of binary compounds.


Genus. Genus. Genus.
. Oxygen. X. Silicium. XIX. Tellurium.
II. Hydrogen. XI. Titanium. XX. Mercury.
111. Nitrogen. XII. Columbium. XXI Molybdenum. ’
IV. Chlorine. XIII. Sulphur. XXII. Tungsten.
V. Bromine. XIV. Selenium. XXIII. Chromium.
VI. Iodine. XV. Arsenic. XXIV. Osmium.
VII. Fluorine. XVI. Phosphorus. XXV. Rhodium.
VIII. Carbon. XVII. Vanadium.
1X. Boron. XVIII. Antimony.
Snconn CLAss—I-AZ/mline Salts.
The different salts composing this class are soluble in water, and possess a marked taste.
Genus. I
XXVI. Ammonia. I
Genus.
XXVII. Potash.
Gem 5.
| xxvnf. Soda.
THIRD Cues—Alkaline Earflzs and Earl/is.
The substances composing this class have a stony aspect; pure, they are without colour or of a milky
white; they are not generally hard. With the exception of corundum, none scratch glass; their sp. gr.
is between 2'7 and 4.0 ; tungstate of lime alone forms an exception to this general rule.
Genus.
XXIX. Baryta.
XXX. Strontia.
Genus.
XXXI. Lime.
XXXII. Magnesia.
Genus.
XXXIII. Yttria.
XXXIV. Alumina.
Founrn CLAss.--Metuls.
This class comprises two divisions, each distinct in aspect :—~
1. Native metals, and the combination of many metals with each other in a metallic state.
2. Combinations of metals with oxygen or with acids. '
The minerals of the first division have generally a metallic lustre, which gives them a remarkable external
character, distinguishing them from other minerals.
The combinations of the metals with oxygen or with acids rarely present this lustre : in this respect they
range among the minerals of the class silicates.
They nevertheless, for the most part, possess a peculiar
colour, which serves as a guide to their study: their sp. gr. is generally high, and almost all upon assay
immediately give a regulus or metallic scoria.
Genus. Genus. Genus.
XXXV. Cerium, XLI. Cadmium. XLVII. Silver.
XXXVI. Manganese. XLII. Lead. XLVIII. Gold.
XXXVII. Iron. XLIII. Tin. XLIX. Platinum.
XXXVIII. Cobalt. XLIV. Bismuth. L. Iridium.
XXXIX. Nickel. XLV. Uranium. LI. Palladium.
XL. Z1110. XLVI. Copper. I
Frr'rn: CLASS.-—Sz'lieules.
The minerals of this class have all a stony aspect, whence they were long known especially. as stones.
They form two distinct groups,—-the hydrous and the anhydrous silicates : the first are soft and easily soluble
in acids : the second are hard; a portion with difficulty soluble in acids; the greater part insoluble in them.
The sp. gr. of the silicates is between 25 and 3'6; a small number only approaching the latter limit.
Genus.
LII. Alnminous silicates.
LIII. Hydrated aluminous silicates.
LIV. Silicates of alumina, of lime, or their iso-
morphic substances.
LV. Aluminous and alkaline silicates, and their
isomorphic substances.
LVI. Aluminous hydrated silicates, with alkalies,
’ lime and their isomorphic substances.
Genus.
LVII. Non-aluminous silicates.
LVIII. Silico-aluminates.
LIX. Silicdfiuates.
LX. Silico-boraies.
LXI. Silico-titanates.
LXH. Silico-sulphurets.
LXIII. Alnminates.
LXIV. Substances of unknown composition.

Srxrn CLAss— Conzbustz'bles.
The minerals constituting this class for the most part present traces of their organic origin: when crystalli-
zation has, as in mellz't‘e, effaced this essential character, we are remmded of it by the nature of the elements
which enter into the composition of the mineral.

(I) Traité de Minéralogie, 4 vols. 8v0.
VOL. II.
Paris, 1814-1347.
290
MINERALO GY.
\
The combustibles of organic origin generally burn with flame at a moderate temperature, giving out a
i They may be divided into the following :-
marked odour. They are soft; their sp. gn, generally very low, does not exceed 16.
1. Resins. 2. Bitumens. 3. Fossil combustibles, comprising anthracite, coal, lignite and peat.
Genus.
LXV. Resins. |
Genus.
LXVI. Bitumens. |
Genus.
LXVII. Fossil combustibles.
. Under these 6'7 heads are now classed more than 500 minerals, which are supposed really to differ suffi-
ciently to be so separated, independently of many which may be considered as varieties or accidental.
The characters of minerals are arranged by M.
Dufrénoy under the following heads :—
1. State of aggregation. Minerals are usually solid;
but some, such as native mercury and certain bitu-
mens, are liquid. Minerals may be distinguished as
liquid, friable, and solid.
2. Colour. Colours are either constant or acci-
dental: when constant and connected with chemical
composition they are characteristic; thus peroxide of
iron is red, sulphuret of lead a peculiar blue-grey, and
so on. Accidental colours are chiefly due to the
mixtures of mineral substances. The peculiar ap-
pearance known as cbatogant depends upon the
structure, and is referred to the cleavage planes, the
reflected light from which changes according to their
position. Labradorite is a good example of this
property.
3. Form. This character does not refer to the
geometric crystalline arrangement, but comprises only
common, imitative, pseaclomorgoboas and pseaeloregalar
forms. The term Common is applied to the mode of
occurrence of the mineral in mass, flagments, plates,
or in an amorphous condition; Imitative, to its occur-
rence in grains, nodules, &c. ; Pseudomorphous, when
a mineral takes the form of a pre-existmg body,
whether organic or inorganic. The term Pseudo-
regular is applied to such arrangement of parts as are
presented by basaltic‘ columns, and other prismatic
forms of igneous rocks, apparently also extending to
the parallelopipeds arising from the intersection of
the divisional plans commonly termed the joints and
cleavage of rocks.
4.. Lastre, such as oitreoas, waa'g, sil/eg, naereoas,
aelamantine, semi-metallic and metallic.
5. Hardness. Minerals are compared with the fol-
lowing scale :--
1, Lamellar Tale; 2, Selenite ; 3, Iceland spar';
4.1, Fluor—spar; 5, Phosphate of lime; 6, Lamellar
felspar; 7, Rock crystal; 8, Topaz; 9, Ruby,
or Sapphire; 10, Diamond.
8. Toagbness, or the resistance which a substance
rofiers to be broken or torn. A soft mineral may be
very tough, such as sulphate of lime; a hard one
readily fractured, as flint; and some minerals are
both hard and tough, as jade.
9. The Scratch. Trials for hardness give a scratch
and powder, which are useful in the determination of
minerals. -Thus the ores of iron, named benzatites,
give a red or yellow ochre powder, which distinguishes
this mineral from the concretionary ores of manga-
nese, the powder of which is black.
10. The Stain. This character applies to a few soft
minerals only. It consists in marking paper or linen
with the mineral: chalk and plumbago are examples.

Plumbago may be thus distinguished from sulphuret
of molybdenum, which it otherwise much resembles.
11. Unctaositg. Many minerals are soft and soapg
to the touch, such as talc and serpentine, magnesian
minerals.
12. Flea'ibilitg. Several minerals are flexible, such
as native silver and copper. Some are both flexible
and elastic, as mica.
13. Dactilitg is chiefly applicable to native metals.
Although sulphuret of silver and halloysite cannot be
lengthened under the hammer, they are nevertheless
termed elaotile by the mineralogist.
1%. Taste is only applicable to certain substances,
distinguished as bitter, sweet, salt, &c.
15. Acllzesion to the tongue is generally sufficient for
distinguishing argillaceous from pure limestones.
16. Odour, such as, of the bitumens and other
similar substances, or that obtained by breathing
on, or rubbing a mineral, when a peculiar odour is
perceived.
17. Colel. The sensation of cold when a mineral is
placed in the hand. Thus rock crystals and gems can
be distinguished from glass and enamels, which other-
wise may be made closely to imitate them.
18. Sonnet. Some substances are very sonorous:
phenolite is named from this property.
19. Weight, as perceived by weighing a mineral
roughly in the hand; carbonate of lime, sulphate of
baryta, and carbonate of lead, may be readily distin-
guished in this way.
With respect to the crystalline types, the follow-
ing is Dufrénoy’s arrangement, founded on that of
Haiiy :—
With perpendicular axes :—
I. Gabe, the modifications of which are the octa-
hedron, the regular rhomboidal dodecahedron, the
hexatetrahedron, the trapezoihedron, the octotria-
hedron, and some other forms.
11. Rigbtprism wit/z a square base, the modifications
of which are the octahedron with a square base, the
dioctahedron, and others.
111. Rig/it rectangular prism, the modifications of
which are the right rhomboidal prism, the rectangular
octahedron, the rhomboidal octahedron, &c.
With oblique axes :—
IV. .Rlzombo/zeclron, including equiaxial rhombo-
hedrons, scalene triangular dodecahedrons, two regular
prisms with six faces, and isosceles triangular dode-
cahedrons.
‘V. Oblique rbomboirlal prism, with its modifications.
V1. Non-sgmmetrical obligae prism, with its modi-
fications.
MINIUM. See LEAD, page 116,
MINT. See Oornrne.
MISPICKEL——MODEL.
2291
MIRROR. See GLASS, SedV‘IIl. Metallic mirrors,
or specula, are noticed under CASTING and Founnln e.
MISPICKEL, or arsenical pyrites, an abundant
source of‘arsenious acid. [See ARSENIQ] It appears
to be a'compound of ‘bisulphuret of iron and arsenuret
of iron, FeAs,FzSz. It occurs native in many parts
of Europe. It is of a more silvery colour than iron
pyrites, and when heated exhales arsenic.
MODEL. When a man of mechanical genius has
invented a machine for the performance of some kind
of work, which had previously been done by manual
labour; or when by rearranging the parts of an old
machine, and introducing new combinations, he in-
vents what is in effect a newr machine, his first trials
as to the efficiency of his invention are generally
made with models, and he is usually satisfied that if
the model answer his expectations, the full-sized
machine is likely to be perfectly successful.
There are reasons which tempt an inventor to con-
struct a model and to rely on the results which are
obtained by its means. A model may be easily con-
structed at no great cost, while the full-sized machine
may be very expensive, and may occupy a large
amount of space. It also does at first sight appear,
that a well-constructed model is a perfect representa-
tion of the arrangement and proportion of the differ-
ent parts of a machine and its mode of action, and
that the performance of the model is commensurate
with that of the machine. But it is nevertheless true,
that a machine may act perfectly well on a small
scale, but'fail when enlarged.
An inventor seldom pauses to inquire into the
relation subsisting between the model and the full-
sized machine. He does not often ascertain what
effect a change of scale has on the strength and’ on‘
the friction of a machine. He may not sufliciently
consider, that when he enlarges the scale on which a
machine is constructed, its surface and bulk are en-
larged in much higher ratios. If the linear dimen-
sions of a machine be all doubled, its surface will be
increased fourfold, and its solidity eightfold. Were
the linear dimensions‘ increased tenfold, the superficies
would be increased 100, and the solidity 1,000 times.1
All machines consist of movable parts sliding or I
turning on others, which are bound together‘ by f ‘
g the square, while the weights to be placed upon
,lthem vary as the cube of the corresponding linear
; dimensions. _
bands, or supported by props. Now, first, as .to the
frame-work. 'In the case of a prop, destined to sus-
tain merely the weight of some part of the machine,
the strength is estimated by so many cwts. per I I
‘to by machine-makers when a change of scale, how-
1 ever small, is to be made; for by attention to it they
square ‘inch of cross section. If, in the model, the
strength of the prop be suflicient for double the load
put upon it, and the scale on which the model was
constructed be enlarged tenfold in the construction of
the machine, the strength of the prop would be aug-
mented 100 times: it would be able to bear 200
loads of the model; but the weight to be put upon it
would actually be 1,000 times that of the small

(1) This mode of viewing the subject, and the general reasonings
and illustrations in this article, are from a paper by Mr. Edward.
Sang, “ On the relation which subsists between amachine and its
model,” read before the Society of Arts for Scotland, and inserted
in J ameson’s Edinburgh New Philosophical Journal for I833.

machine; so that, in fact, the prop in the large ma-
chine would be able to bear only 15th part of the load
to be put upon it: it would in fact fall to pieces by
its own Weight.
We see, then, in this case, how inaccurately the
model represents the performance of the larger ma-
‘chine. It is evident that the supports of small objects
ought to be proportionally smaller than those of larger
ones; and we see how beautifully Nature changes her
proportions at each change of size. If the proportions
of an elephant were given with the size of a mouse,
the limbs would be too strong and unwieldy; and if
a mouse were enlarged to the size of an elephant, its
limbs would be totally unable to sustain the weight
of its body.
The same principle will apply to bodies in a state
of distension. Suppose, for example, the chains of
a suspension-bridge were computed to bear 9 times
the load put on them, and that a similar structure
were formed of 10 times the linear dimensions, the
strength of the new chain would be 100 times greater,
while the load put upon it would be increased 1,000
times, so that the new structure would possess only
g’fiths of the strength necessary to support itself.
Hence how little important it is to show that a model
of a bridge, constructed on a scale of probably 1 to
100, will support its own weight, since the weight‘bf
the enlarged chain would have torn itself to pieces,
supposing it could even have been raised. It is stated,
that the larger spiders spin threads much thicker
‘ in comparison with the diameter of their own bodies
than those spun by smaller ones.
When a beam gives support laterally, its strength
is proportional to its breadth and to the ‘square of its
depth conjointly. If such a beam be‘ enlarged 10
times in each of its linear dimensions, its ability to
sustain a’ weight placed at its extremity would, on
account of the increased distance from the point of
insertion, be increased only 100 times, while the load
to be put upon it would be increased 1,000 ‘times;
and thus, although the parts of the model may be
quite strong enough, it does not follow that those of
§ the enlarged machine will be so.
It will be seen, from these illustrations, that in
similar‘ machines the strengths of the parts vary as
This general principle ought to be carefully attended
will conduce to the sufficiency or economy of the
structure. To enlarge or diminish the parts of a
machine in the same proportion is clearly wrong.
Enlarge a midge until its whole weight is equal to
that of a sea-eagle, and great as'the enlargement is,
its wing would scarcely be equal to the thickness of
:writing-paper. It should be remembered that the
larger animals are not supported laterally, their limbs
being always nearly vertical; as we descend in the
'scale of size, the lateral support becomes more
- frequent, until we arrive at whole‘ classes of insects
c2
29:2
MODEL.
which rest on limbs placed in nearly a horizontal
position.
Having thus noticed the relative strengths of a
machine and its model while at rest, let us compare
their relative strengths and actions when in motion.
This subject may be considered under two heads, the
one relating to the ability of the structure to resist
the blows given by the moving parts, either in their
ordinary action, or when by accident they escape from
their usual course; the other relates to the changes
which take place in the friction of the parts when
enlarged or diminished.
The ability of a support to resist the impetus of a
moving body, is estimated by combining the pressure
which it is able to bear with the distance through
which it can yield before it breaks. In the case of
a support which acts longitudinally, the strength is
proportional to the square of the linear dimension,
while the distance through which it can yield is as
the linear dimension itself. Altogether, then, the
ability to resist a blow is proportional to the cube of
the length; that is, to the weight of the body which
is destined to act upon it. If, then, the linear velocity
of the machine is to be the same with that of the
model, these parts, as far as this action is concerned,
will be in keeping with each other.
In the case, however, of a lateral support, the
distance through which it can yield without breaking
is not augmented by an enlargement of the scale; so
that in these parts, the large engine is comparatively
weak, even though the velocity of the motion be the
same on the large as on the small scale,
But those motions which are most likely to produce
accidents in this way, are generated by descents,
which bear a fixed proportion to the dimension of
the ‘engine. The velocity, therefore, is generally
greater in the large engine than in the small one, so
that large machines are more liable to accidents
arising from the derangement of any of their motions
than small ones: they possess, however, more abso-
lute strength, and are better able to resist any ex-
traneous force. But we must carefully distinguish
between the absolute strength of any structure or
the power which it has of resisting impressions from
without, and the ability of that structure to with-
stand the effects of derangement among its own
parts.
When we consider its ability to resist mere pres-
sure, or its ability to resist an impulse, the perform-
ance of an engine is not at all commensurate with
that of its model. As great a disparity is perceived,
when we consider the friction of the parts. For
example, “ the steam-engine moves on account of
the pressure of the steam against the surface of the
piston, which pressure may be estimated at about
10 lbs. per circular inch. The friction which this
pressure has to overcome, may be divided into three
parts: the first including all friction caused by the
packing of the piston‘ and stuffing-boxes, and which
is proportional to ,the linear dimension simply; the
second including that part of the friction on the
gudgeons which arises from the pressure of the

steam upon the piston, and all other friction propor-
tional to the square of the linear dimension; and
the third including all that friction which arises from
the weight of the parts, and which is thus propor-
tional to the cube of the dimension. Suppose that
in an engine whose cylinder is 20 inches across, and
whose inciting pressure will thus be 41,0001bs., the
friction of each kind is 1001bs., the entire friction
being thus 3001bs., or about Tlgth part of the moving
force. From this model let us construct an engine
on the enlarged scale of 20 to 1. The new cylinder
will be 4,000 inches in diameter, and the pressure on
the piston 1,600,000 lbs. The friction of the first
species would amount to 2,000, that of the second
to 410,000, and that of the third to 800,0001bs., so
that the sum total of the friction, no less than
$412,000 lbs., would be fully more than half of the
inciting pressure. It is, then, clear that such an enor-
mous engine would be highly disadvantageous as a
mechanical agent, and that if the enlargement were
pushed a little further, the whole of the moving force
would be expended in overcoming the friction. There
is, then, a greatest size, beyond which it is impossible
to proceed in the construction of the steam~engine.
But there is also a least. Let us take an engine
similar to our first, but with a cylinder of only 1
inch in diameter. In such an engine, the pressure of
the steam upon the piston would be only 10 lbs. : the
three kinds of friction would amount respectively to
51bs., 1 gr., and 1-80th part of a pound; the first kind
alone being equal to half the inciting force. Were
the diminution still further continued, the friction of
the packing of the piston might equal the pressure of
the steam. From this it is apparent, that for each
shape of steam-engine, there are two extreme limits
as to size, at which the utility of the engine ceases
altogether, and between which there is placed a best
size, or one which is accompanied by the most com-
plete development of the powers of the engine.
A skilful arrangement of the parts may, indeed,
extend the limits both ways, and may thus change
considerably the most advantageous size; yet even
with that assistance, very small or very large engines
are less productive of force, in proportion to the
quantity of coal they consume, than moderately
sized ones are; and in many instances, it would have
been better to have employed two or three middle-
sized engines, than a single one possessed of two or
three times the nominal power.”
In conclusion, then, it may be stated that every
instrument, whether it be used for the generation or
for the transference of power, has a best size, and a
best form: that security demands strength, strength
requires weight, weight increases the friction, the
friction calls for additional power, and power can
only be procured by an increase of weight. To re~
concile these, conflicting claims, is not a task for a
beginner in mechanical contrivances, but for one well
versed in the theory and in the practice of the arts.
Models have only a limited use, for although they
may perform well, that is no guarantee for the suc—
cessful performance of the full-sized machines.
l\'IODELLlNG-—MOLYBDENUM..
293
MODELLING, an art which depends almost
entirely on the skill, taste, and manipulation of the
operator, and is nearly independent of tools.
Modelling tools are either loops of wire of different
sizes fixed in wooden handles, or variously shaped
pieces of ebony or box-wood. Both are to be con-
sidered merely as occasional aids to the fingers, or to
be used in portions of the work which the latter
cannot reach. The wire tools are convenient for
removing portions of clay by drawing the wire under
them, and so leaving the adjacent parts undisturbed.
The clay thus severed remains adhering to the model
until its own weight causes it to fall, or until it is
gently removed by the operator. These tools also
assist the modeller in producing concave surfaces,
narrow folds of drapery, &c., the wire being some-
times notched where a rough effect is required. The
wooden tools may be sharp-pointed or blunt, straight
or curved, flat or round, narrow or broad. The broad
tools assist the formation of large convex surfaces,
and the more ample folds of drapery. l/Vooden tools
for fine work are generally kept soaked in oil to
prevent the clay from adhering to them.
The material used in modelling, is common potter’s
clay of the best quality, made so wet, that a mass of
it will not stand much higher than its own width
without support. It is necessary throughout the
various stages of the work, that the moisture should
be sustained as nearly equal as possible, and that
means should be used to prevent the model from
drying during the night, or when it is not under the
operator’s hands. This is not difiicult to accomplish,
for while the figure is exposed and in progress, it can
.be frequently sprinkled with water by means of_ a
plasterer’s brush, and when it is laid aside for the
night, the moisture can be sustained by means of a
wet sheet wrapped around it. Another way of pre-
serving the moisture for a considerable time without
adding water, is to draw over the model an air-tight
case or bag, and to make the same fast with clay to
the plinth. A very wet state of the clay in modelling,
causes the clay to adhere more to the tools, but at
the same time greatly facilitates the proceedings of
the modeller, and saves his time.
During the progress of the work, careful and suffi-
cient support must be given to the model, or after all
the labour of the artist, it may fall to pieces when it
is finished. In modelling a bust, the only support
required is an upright piece of wood with a cross-bar
at the shoulders {but forua full length figure, especially
if in any unusual attitude, the nature of the supports
requires the most minute and careful attention.
Figures of the ordinary size are generally modelled
upon a bench or stand called a banker, 2% feet high,
and 2% feet square; above this a solid circular plinth
is fixed on a wooden boss, and turns upon 6 or
more wheels, or preferably, upon short slightly conical
rollers, fixed to the plinth near the circumference.
A revolving plinth is necessary to enable the sculptor
to view his work in all directions, and in any light, and
to work on it in the most favourable position. On
the centre of this revolving plinth, is fixed a strong

iron bar the height of the intended figure, and from
6 to 10 inches in circumference. This is to be the
main support of a skeleton-work of other supports,
for the protection of the limbs, draperies, 850. At
the shoulders and loins two cross-pieces of wood are
fixed to the main bar, from which the supports of the
arms and legs are projected; sometimes it is desirable
to have a third cross-piece, midway between the two
others, for the better support of the clay. The supports
of the legs consist of stout bars either straight or
bent, according to the position of the figure; those
of the arms, when not detached from the body or
drapery, may be made of twisted thick copper wire,
with short pieces of wood at intervals twisted in with
the wire, and at right angles, like the pieces of paper
in the tail of a kite. The fingers, if separate, will also
each require separate support. The entire skeleton
of supports must be so strong and unyielding as not
to give way in any degree under the mass of clay
that is to be built up against it. The construction
of such a skeleton, therefore, requires an experienced
and able hand, and will take many days of labour.
A novice in the art would always do well to get the
supports for his early works constructed by an expe-
rienced person.
A model should always be made of the size of the
intended figure, for although there are facilities for
increasing the scale at pleasure, yet it is found that
trifling errors in a small model become multiplied in
the larger one to such a degree as to give the artist
much after labour. In former days, the sculptor, on
the completion of his model, adopted the cheap, and
easy method of baking it in an oven. These baked
models, called term coz‘m, or baked earth, were
usually of small size, and are extremely numerous,
but there are also a few of large dimensions pre-
served in museums. There is, however, a great
objection to this plan; namely, the shrinking, and
sometimes the cracking of the clay under the influence
of heat. The present method is to take a plaster
cast, from which to work the marble or to take other
casts. The whole model, while wet, is covered in
two or three or more masses with plaster-of-Paris,
and when this is well set and dry, the whole may be
separated without any regard to the preservation of
the original model, for when the mould is obtained,
the model is no longer wanted. All the clay being
completely removed from the mould, and the parts of
the mould put together again, plaster-of-Paris is
poured in until the mould is filled. After allowing a
proper time for drying, the mould is carefully broken
off in fragments, and the perfect cast exposed. Sup-
posing other casts to be required, another mould,
called a sage-mould, must be made in many parts; and
if the figure is to be executed in marble, it must be
copied by means of the pointing-machine. See
SCULPTURE.
MOHAIR, the hair of a goat in the vicinity of
Angora, in Asia Minor. See WEAVING.
MOIREE METALLIQUE. See TIN.
MOLASSES. See Susan.
MOLYBDENUM (Mo 48), a rare metal found in
294:
MOLYBDENUM—MORTARS AND CEMENTS.
'cbalttg, pulverulent, concreteel, Sec.
the form of a sulphuret, from which molybdic acid was
first prepared by Scheele in 17 7 8, and from the acid
the metal was obtained by Hielm in 1782. The acid
must be intensely heated in a crucible lined with
charcoal. The metal is white, brittle, and very infu—
sible. Its density is 8'6 : it oxidises when heated in
the air, and forms molybdic acid M003. ~
MOMENTUM.- See sutures and Drnnnrcs.
MONTGOLFIERE. ~See Annosrx'rron.
MORDANT. See Drum G—'-OALIOO PRINTING.
MOROCCO. See LEATHER.
MORPHIA or MORPHIN-E'. ' See OPIUM.
MORTAR. See TRITURATION.
MORTARS and CEMENTS. Mortar is a substance
placed between stones-and bricks for the purpose of
cementing them» together. It "consists essentially of
lime ‘and siliceous sand, the lime being in the state
of hydrate. The sand used is of ~ different degrees of
fineni'ass, from river or pit sand up to coarse gravel,
which latter, being mixed with the lime or mortar,
forms what is called concrete. When the lime which
is used in making mortar has been prepared from a
limestone containing clay, or argillaceous matter, in
certain proportions, the mortar possesses the pro-
perty of setting‘ or solidifying under water: such a
lime is termed bgrlraalic lime, and the mortar made
from it lzga'raalic mortar. Mortars of this kind are
often termed cements, without any very sufficient rea-
son, since every kind of mortar is properly a cement.
Hydraulic mortars are also prepared with lime and
certain volcanic productions, known as paozzolano,
and trass, and even certain products of artificial cal—
cination, such as bricks, tiles, coarse pottery, cinders,
furnace slag, die.
- But as the basis of mortars and cements is lime,
we propose first to- consider, at some length, the in-
dustrial methods of preparing this important substance.
A variety of particulars respecting lime, or its car-
bonates, are given under LIME, MARBLE, OARBONIG *
ACID, and it is to the carbonates of lime that we must
now direct attention.
Pure carbonate of lime, CaO, CO2, occurs native in
calcareous spar and a few other minerals ; but most
of the calcareous - rocks ‘contain other ingredients in
addition to carbonic acid and oxide of calcium: these
ingredients are magnesia, oxide of iron, manganese,
clay, bitumen, quartzose sand, &c. The term time-
stone is applied to those stones which contain at least
one—half of their weight of carbonate of lime; and
according to the other prevailing ingredients a lime-
stone may be argillaceoas, magnesian, sanclg, jerrngi-
noas, bitaminoas, jetz'el, 85c. These varieties are further
distinguished according to their forms and texture,
as lamellar, ‘sac‘cbaroiel, granalar, compact, oolitic,
Now the lime ob—
tained from one or other of these stones varies in
quality, colour, ‘weight, avidity for water, and the
degree of hardness which it assumes when made into
mortar.
Lime is prepared from limestone by the action of
heat in kilns, arranged so as to deprive the limestone
of- its carbonic’ acid, as completely as possible, in the

shortest time, with the smallest quantity of fuel, and
with the least amount of labour.
Lime-kihls are variously constructed, according to
the method of working them, and the kind of fuel to
be used. In places where materials areexpensive on
account of their carriage, and where the fuel is coal,
the form of kiln is generally that of an inverted cone;
but this form is not considered by practical lime—
burners‘ to be equal to the elliptical, or ovoidal, the
latter resembling the form of an egg placed upon its
narrow end, with part of its broader end struck off
and its sides-somewhat compressed, especially towards
the lower extremity; the ground plot, or bottom of
the kihl, being nearly an oval, with any ege or draft.-
hole towards each end of it.‘ The advantages of this
form over'the cone are, that, by contracting the'upper
part of the kiln, the heat does not escape so freely as
it does out of aspreading cone, but is reflected back
upon the materials. Another advantage is, that when
the cooled lime is drawn out at the bottom, the ignited
mass in the upper part settles down evenly into the
central part of the kiln; whereas, with a conical form,
the regular contraction in width prevents the burning
materials from settling uniformly: they hang upon
the sides, and either form a dome at the bottom with
a void space beneath it, endangering the structure, if
not the workmen; or, breaking down in the centre,
form a funnel, down which the unburnt stones find their
way to the draft-holes. The contraction of the lower
part of the kiln has not the same effect, for when the
fuel is burnt out the mass loosens, and as the lime
cools it occupies less space, and runs down freely
to the draft-holes.
.The oldest kiln is probably that produced by ex-
cavating the earth in the form of a cone, and
building up the sides, if necessary. Alternate layers
of fuel and stone properly broken are then laid in,
until the whole is filled up. The top is covered with
sods, to prevent the loss of heat: the fire is lighted
at the bottom. The sides of such a kiln, which is
’ called a sod—leiln, are sometimes lined with sods.
When the fire has burnt out, and the contents are
cold, they are drawn out from the bottom, and the
kiln is again filled. A superior kiln of this kind as
used in the neighbourhood of Lille, is shown in
1&7 3. It is charged with alternate layers of
coal and limestone, in the proportion of 41 measures








A‘ ‘g
‘ w" Qt“ ‘-
"\w‘ w
§§X\‘sl§? ems W
‘ \‘Mg.
sea 7 ..
\. ‘~ ' - /\\ \ A I > _
h \ " . ' l ‘ .



of limestone to 1 of coal or 1% of coke. The coal is
wetted before being used. When the calcination is
complete, which is known by the subsidence of the
. mass, and the flame at the top being nearly destitute
MORTARS AND GEMENTS: $395
of smoke, about two-thirds of the contents of the
kiln are extracted at the bottom, and the empty space
gradually filled up with alternate layers as before.
Where lime is constantly required in large quantities,
the operation is made still more continuous in what
are called draw-kilns or'mmzz'zzg-isz'lizs. These may be
situated by the side of a rising bank, or sheltered by
an artificial mound of earth. They may be of stone
or of brick; the latter being often pref erred,-as being
better calculated to withstand the heat. The outside
form of such kilns may be cylindrical or square.
The interior is in the shape of a hogshead, or an egg
opened a little at both ends, and set on the smaller.
Near the bottom, two or more openings are made:
these are small at the inside of the kiln, but widen
out as they extend to the outside. These holes
supply air to the furnace, and allow the labourers to
approach with a drag and shovel to draw out the
burnt lime; Within the kiln, at the bottom, a wedge-
shaped projection, Fig. M7 5, called a lzorse, is some-
times formed, to assist the drawing out of the lime
by directing it towards the apertures. Or instead of
this, there may be an iron grate near the ‘bottom,
coming close to the inside wall, except at the aper-
tures where the lime is drawn out. l/Vhen the kiln
is to be charged, a quantity of furze or fagots is
laid at the bottom, over this a layer of coals, then a
layer of limestone in pieces about the size of a man’s
fist, and so on alternately, ending with a layer of
coals, which may be covered over with turf to retain
the heat. The fire is lighted at the apertures, and
when the limestone at the bottom is well burnt, that
at the top sinks down. The men then add lime-
stone and coal at the top, and draw out at bottom as
it is burnt. In this way, large quantities of lime may


E weaning‘
.- i 4




$155


E


d


iii-ll‘.
l uni—militiamen
ll." ‘




Yfl/l/l/J/Il/ll/l/VM/ll/I/l/l/f:
Fig. 1475.
Fig. 1474.
be produced in a short time. When coal is used,
three bushels or more of calcined limestone are pro-
duced for every bushel of deals consumed. "
Akiln of this kind, adapted
for burning one part wood
and four of turf, as used at
Rudersdorf, in Prussia, is
shown in elevation, vertical
section, and plan, Figs. 14:74,
1475, 1476. This kiln has
five fires, f j, distributed
round it: a is the ash-pit,
closed by a door; 0 openings for regulatipg the
draught 5 0 larger openings for drawing the lime.


It will be seen by the section, Fig. 1475, that the.
kiln is lined with a double shirt of fire-bricks, s,’
between which and the masonry, m, is a space, a,
filled with cinders well rammed, by which arrange-
ment the heat is prevented from escaping.
Figs. 147 7, 1478, represent a continuous kiln used in
Belgium, and capable of producing‘ lime in enormous
quantities. The kiln is charged with alternate layers
of coal and lime-
stone in the pro- \
portions used for ‘ .._


the kiln, rignvs, and when once the kiln is at the ‘
proper heat, lime ‘-
can be constantly \ V K .\...._;.....g.,.._.\ww_se-m.
withdrawn from \ ‘l \ N‘l'iii‘ili‘i"\i\\v‘““ ‘
the eight open-
ings at the bot-
tom one after the ‘ '~
other, while fresh
portions of the
charge are con- \“
stantly added at
the top. When
the supply of lime
is satisfied for a
time, the bottom openings are stopped up, and the
top is covered with stones and clay, and in this con-
dition the whole mass will remain incandescent for
more than 8 days. Once a-yea'r the kiln is allowed
to cool, for the purpose of inspection and repairs.
_A lime-kiln constructed by Oount Rumford deserves
notice. Its objects are, 1. To cause the fuel to burn
so as to consume the smoke, which is made to descend
and pass through the fire; 2. To cause the flame and


a
/


-.‘<~\.-*e~<-:~re'\\\"swrm\s: "r
‘1 see?" ‘“\\“\‘\\ssi
Figs. i477, 1478.
hot vapour from the 'fire to come in contact with the '
limestone by a very large surface, which is done by
making the body of the kiln in the form of a ‘hollow
truncated cone, and very high in proportion to its‘
diameter; and by filling it quite up to the top with
limestone, the fire being placed near the bottom of
the cone; 3. To make the process continuous, and
thus prevent loss of heat by putting out and relighting;
4:. To cause the lime which is properly burnt and fit
forwithdrawing to giveoff its heat intov the kiln, so
as to assist in burning the fresh stone which may be
added. In this kiln, the fuel is not mixed with‘ the
limestone, but is burnt in a close fireplace, which
opens into one side of the kiln some distance from the
bottom. In large kilns there may be several such
fireplaces, opening into the kiln on different sides.
At the bottom of the kiln is a door for taking
out the lime. When a portion of the lime is with-
drawn, the contents of the kiln settle down or subside,
and fresh limestone is added at the top, and the door
is nearly closed with moist clay. As the fire enters
the kiln at some distance from the bottom, and as the
flame rises as soon as it enters this cavity, the lower
part of the kiln, or that below the level of the fire, is
occupied by lime already burned, which being intensely
, heated, radiates its heat upwards, and thus assists the
296
' MO‘RTA'RS AND (JEMENTS.
fire in'burning the fresh limestone. "To assist this»
action of the red-hotlime, air is allowed to enter by
a small hole in the lower door, by which means a
current of highly heated air is brought into contact
with the fresh limestone. The height of-the kiln may
be 1.5 vfeet‘; its vinternalv diameter 2 feet below and 9 1
inches above. In orderto. confine the heat, the walls,
which are brick,~and veryitfhing'are double, andthe
cayity between them filledv with dry wood-ashes. The
‘are connectiédlfin- different places _ by hori-
zontalti-layers of brick, for the sake of strength. 0 is
by ‘introduced: ite‘is covered .
'byi'anfif'ii'on plate moving ony__i_iliinges, which plate being
l-liftedi‘iup more or less by vmeans of a. chain, serves as a
' ‘ ' " register: 0' isan open--
ingsin the front wall
of the fireplace,‘ for
. cleaning» it‘ out, and
also for allowing the
flame to pass from the
fireplacev into thev kiln.
This opening must
not be entirely closed,
as it ‘admits a small
quantity-of air hori-
zontally into the fire-
place, and facilitates
- the combustion of the
smoke. Several small
holes for this purpose,
fitted with conical
stoppers, may be made
in different parts of
the front wall of the
fireplace. The bottom
of the fireplace is a grate, constructed of bricks
placed vedgeways, and under the grate is an ash-pit,
the door of which a is kept constantly closed (except
for removing the ashes), to prevent air from passing
through the grate into the fireplace : Z is the opening
by which the lime is taken out ; and in order that
no more'lime may be removed than that which oc-
cupies the-space below the level-4 of the fireplace, a
pit of the, same dimensions may be placed near the
door, for the purpose of measuring the lime. .W'hile
the lime is being removed, fresh limestone is added
at‘ the top, the fire being damped meanwhile by closing
the iron plate. At other times the-fire may be further


x 161/
.\ _\\\_ I \< - \ \ r
‘ ~ N.
damped, if‘ required, .by placing a flat fire-stone or'
plate of iron more or less over the top of the kiln.
- -_.- In places where furze is used. for burning lime,
flame-‘kilns, as they are called, are‘ constructed. They
are of -brick,iwith the ‘walls from '4: to 5 feet thick,
unless they'can, be supported by a mound of earth.
The interior is 12 feet by 13, and the height '11 or 12
feet; TIn thegfront wall are‘three arches, each about
- 1;foot.._;10,inehes wide. by‘ 3 feet 9 inches high. When‘
the kiln is it)" be; filled, the largest -pieces.of ‘lime;
stone‘ are built up ‘in the form of arches, thewhole
breadth of the kiln, ‘and opposite to the arches in-
. thevfront-wall; I The remainder oflthe limestone is
— s then» thrown into‘ the kiln, to the heightJ of 7 or 8 feet,
Q
oiverwhichare frequently laid 15,000 or 20,000bricks,
which are burnt with the‘ limestone. When the kiln
is filled, the three arches in the front wall are filled
up with bricks nearly to the top, space being left in
each sufficient for putting in the furze in small quan-
tities at a time,_so as to maintain a constant flame.
In about 36' or 410‘ hours the limestone, about 120 or
130 quarters, together with the bricks, are properly
calcined. Fig. M80 represents an intermittent kiln
of a truncated ovoidal form, the space K being about
15 feet high, 10 feet'I-in- diameter in the middle, 5 feet
at the top, and about 7v feet at the bottom. Air for
' c SSS 0110' - e '."\ \ \t f‘ig;
channel efand .
up the small ya'fiiifi'zbm opening 0: I2. is i‘
the opening for
the fuel.
A better form
of furnace on i ,








J




this
\
i l“ -
this principle is \\ 2
shown in Figs.‘ ._ 1 4:81, 14.82. '
This furnace is constructed of rough masonry, and
lined with a shirt of fire-bricks. In charging the
furnace, the larger fragments of limestone are built
3
:' f2“:


Fig. use.
’,-/-\__-_a___-_








(a: ', ‘ll-"ff;
, y, , "Pdffi . //
/// $7,, I ~ -' /



A /
'7 -V. . _..

Fa]- 1431.
up into the form of a vault, supported by the abut-
- ments 6 6. This vault supports the rest of the charge,
which is thrown in at the top. care being taken to
arrange the large pieces in the middle, the smaller
ones near the sides, and to fill up with the smallest
fragments. A turf fire is‘lighteduponft'he‘grate I) b,
which is made of moveable bars, and the fire door as
well as the door of the ash-pit a are closed. The
fire is supplied-with air- by a small opening or channel
0, and- is left for 110 or 12 hours, during which the
limestone is blackened .by the.‘ smoke, andgradually
heated ; the fire isthen gently urged until the charge
about one_-thi_rd.;_upf“is raised from a red‘ to a white
heat. When. th'evma'ss has subsided, and the flame
escapes at the‘ t'opwithout smoke, the operation is
finished.‘ .-In--this kiln 2 volumes of turf suffice for
the calcination of _ 1 volume of limestone. _
In-somepar-ts: of Scotland and other-places where
- coalisf, dear, limestone is burnt with peat in alternate
s'trata'of limestoneand peat in kilns formed of turf ;
but the-‘quantity of ashes produced by the-peat injures

thequality 'Ofi‘tlleiilimc, and the. waste of fueliscon-
{pronrans AND CEil’lEN-TS.
'29.’?
side'rable. But the more common method is 'to con-
struct peat kilns similar to vthose in which furze is
used, only there are'but two arches or fireplaces, and
the peats are thrown in at the bottom : the front is
seldom closed up, so that there is too much draft, and
the limestone ‘is not properly calcined. This is re-
medied by placing an iron grate across the bottom of
the arch with an ashpit below, and closing the front
of the arch by an iron door. ' -
A form of kiln invented by Mr. Booker of Dublin,
consisted of two long narrow truncated cones placed
end to end; the diameter was 7 feet in the middle,
and 3 feet at the top and at the base; the height.25»
to 30 feet. The top was furnished with a cast-iron
cap or cover turning on a pivot: this served to regu~
late the heat. This kiln was greatly improved by
C. J. Stuart Menteath, Esq. of Closeburn in Dum-
fries-shire. Mr. ‘London, in his Encyclopaedia of
Cottage, Farm andVil‘la Architecture (184:2), declares
it to be the
best lime-kiln
i he had ever
seen or heard
of. The best
' situation for
this, or indeed
for most other
forms of kiln,
is the face of
_ a steep bank;
but if this cannot be obtained, it may be constructed
on a level‘ surface with a-ramped road or incline, or
with a mechanical lift for conveying the materials to the
top of the kiln. Fig. 14-83 is a section across a bank
on the face of which
0 ' ~the kiln is to be
built. a b 0 (Z indi-
cate the space to be
occupied by the kiln,
and c 41 cf the si-
tuation of the shed



1484.‘ is a ground
plan, in which 5 is
‘the fuel chamber,
2 feet square, with
iron bars across : two air openings ii at the side may
be more or less closed by stones: g/zg is the space
for the cart when loading with the lime as drawn
out of the kiln. Fig. 1485 is a horizontal section of
the kiln at the
height of 18 feet
from the grating of
the fuel chamber,
or on the line AB
of Fig. 1488; Fig.
14:86 is a plan of
the top of the kiln
covered by the shed. In this plan lair/r are the 3
circular openings in the covering arch, through which
the broken, stones and fuel are introduced‘; these
holes may be covered with iron plates or valves: Z is


9' - . 9
Fig. 1484.




over the mouth. Fig,

the‘place for the fuel, and m'r-for the limestone, the
cart for conveying these materials passing in v‘at one



Fig. 1486.
door and out at the other. Fig. M87 is a vertical
section of the kiln, on the line BE, in which a is the
side opening to the back of the fuel chamber; -0 cast-
iron covers, with openings in the centre and- lids
over them, to the feeding apertures,'and 12 the spring.
ing of the covering arch. Fig. ld88iis ‘a transverse
section of the kiln and shed on theline Quin-which
g is the fuel chamber ; r the space between the double
doors of this chamber; ‘
s the covered area on
which the loading carts
stand; a‘ the cast-iron
to. the feeding
aperture, and u the
cover to the chimney of
the kiln shed. The
walls are of fire-brick or





0 0 0
Tu l I | I 1'
TL’ ' fi" ‘——1—
_____.l .__..
J... l i
._l_ \
l )
“i ' ‘T'—
..__L_
.41‘ , '5;
i I
I | ‘
l l
1 |
a c
--___l 2
i 1
l l t I
t
t
l ' I l
l l
t -2
l 7?’ ~
Fig. 1487. Fig..14-S8.
fire-stone, or even of burned limestone of the ‘same
quality as that burned within, only in large masses to
prevent their being so much affected by the heat. The
upper part of the kiln may be arched over or covered
with cast-iron joists‘ and fiagstones, with square or 0b-
long holes for the admission of air, and-covered with a
plate of cast-iron for the regulation of the draught.
The shed over the mouth of 'the kiln is of great use,
not only in keeping the materials dry, but in heating
them before they are thrown into the kiln. The
double iron doors to the fuel chamber should be'from
9 to 12 inches apart; but single doors will sulficc for
the ash-pit. The side openings for the admission of
air may be more or less blocked up with stones, to
save the cost'of iron doors. The bars of the grating
298
MORTARS-AN D GEMENTS.
.of the charge.
of the fuel chamber may be 2%- feet long, 2 inches
wide and 3 inches deep, cast hollow: and the two
cross bars on which theyrest may be 3 inches broad
and 5 inches deep, also cast hollow. The metal need
not in either case exceed :1— inch in thickness: the
current of air passing through the hollows contributes
to the durability of the bars. The opening behind the
fuel chamber for the admission of an extra supply of
air is furnished with a grating, where it enters the
fuel chamber to prevent its being choked up by the
lime either during the burning or the drawing. Mr.
Menteath states that a kiln in which coke is the fuel
yields nearly one-third more calcined lime, or s/iells
as it is termed in Scotland, in a given time than
one in which coal is the fuel.
The time required for burning lime depends greatly
on the size of the pieces of limestone, their density
and state of dryness. The time will be shorter when
the stone is not dense, when the lumps are small and
have a certain degree of moisture. This is so well
known to lime-burners that they are accustomed to
water the stone just before burning, unless they can
use it fresh from the quarry. The action of the water
in facilitating the escape of carbonic acid from the
limestone is not very clear: it may be simply mole-
cular, or the water may for a short time take the
place of the carbonic acid, and form a hydrate which
is itself decomposed as the heat increases; or the
water may be decomposed by the fuel, and the result-
ing hydrogen and oxygen react in several ways upon
the carbonic acid; one result would be the production
of carbonic oxide, which, being inflammable, would
assist in expelling carbonic acid from the limestone.
It must also be remembered that in those limestones
which contain clay, silica, magnesia, oxide of iron, 850.,
these substances tend to combine with the lime, and
thus greatly facilitate the escape of carbonic acid.
When fuel is abundant, or where labour is scarce,
and the nature of the stone does not admit of its being
broken up into small pieces, the largest blocks are
placed in the centre of the kiln. Care must be taken
not to overburn or bill the lime, as it is called, for if
such be the case, it will not set or solidify. So also
the lime must not be underburnt. The lime-burner
will judge by certain appearances as to the time
required, which varies with the nature of the stone
and the fuel, the draught of the kiln, the state of the
weather, and the direction of the wind.~ Before the
burning is completed, the stones crack, the interstices
diminish, the mass gradually sinks down %th or :1,-th of
its height, and the lime-burner ascertains whether the
calcination is complete by driving a bar into the body
If it meet with considerable resist-
ance, or strike against firm hard materials, the burning
is evidently incomplete; but if it pass down easily,
and meet with no more resistance than in passing
through a mass of gravel, the burning is considered
to be finished. Another test is, to draw a portion of
the lime and slake it; but this is liable to error, for
the lime will evidently vary in quality with its position
~in the kiln; ' .
The behaviour of lime when slaaed ,or' slacleed with

water, is subject to much variation in difierent kinds
of lime, and establishes certain important distinc‘
tions between them. Suppose, by way of experiment,
the lime to be fresh, and to be immersed in a small
basket in pure water for 5 or 6 seconds: the water
is then allowed to run ofi, and the contents of the
basket are turned into a stone or iron vessel. The
observed phenomena may be as follows :——1. The
lime hisses, crackles, swells, gives off much hot
vapour, and immediately falls to powder. Or, 2. The
lime remains apparently inactive for a variable time,
not exceeding5 or 6 minutes, after which the phe-
nomena described under (1) become energetically
developed. 3. The lime may appear to be inert for from
5 or 6 to 15 minutes; it then begins to smoke and
decrepitate, but the heat and vapour are less than in
(1), (2). 4!. The above phenomena may not commence
for an hour, or for a still longer time. The lime
opens into cracks without any noise, and but little
heat or steam is produced. 5. The phenomena are
produced at very variable periods, and are scarcely
perceptible. The heat is only evident to the touch:
the lime does not readily fall into powder, and in
some cases not at all.
Before the effervescent action has quite disap-
peared, the slacking of the lime should be completed.
When the lime begins to crack and fall to pieces,
water is to be poured down the sides of the vessel,
so as to flow to the bottom, and to be absorbed by
the lime. It should now be frequently stirred, and
sulficient water he added not to flood it, but to bring
it into a thick paste. It should then be left to itself
to cool, and this may occupy two, three, or more hours;
The lime should then be beaten up again, and more
water added if necessary, still keeping it in the form
of a tolerably stiff paste. A vessel should then be
well filled with this paste, and placed under water,
the time of the immersion being noted.
By treating limes in this manner, and carefully ob-
serving the results, they have been divided into five
classes; viz. 1, the rich limes; 2, the poor limes;
3, ligdranlio limes of moderate power; 41, lzgdraalic limes
properly so called; 5, very energetic bgcb'aalic limes.
1. The rich limes consist of pure, or nearly pure,
oxide of calcium; and the purer the carbonate of
lime from which they are produced, the more decided
are the phenomena exhibited in slaking. They in-
crease in volume to twice their original bulk, and even
more: their consistency does not change, i. e. they do
not set or solidify after years of immersion, and if
exposed to pure water, frequently renewed, they
would be entirely dissolved. 2. The poor limes, on
being slaked, do not increase in bulk, or only to a
trifling extent. They do not set under water, and they
are dissolved by it, but a small insoluble residuum is
left. 3; The hydraulic limes of medium power, set
after 15 or 20 days’ immersion, and continue to harden
for months : in about a year their consistence is equal
to that of hard soap. They dissolve with difficulty in
water frequently renewed; they change in bulk on
slaking" Similar to the poor limes. 41. The hydraulic
limes set in 6_ or 8 days after immersion, and continue
.MORTARS AND CEMENTS.
299
toharden for "6 months. In "12 months they are of the
consistenceof the softer building-stones, and water
has no longer any action on them. Their change in
bulk isaboutthat of the poor limes. 5. The energetic
hydraulic limes set in 3 or 41 days ‘after immersion:
theyiare quite hard in a month,land are not acted on
by running water: in ‘6 months ‘they can be worked
like the harder ' natural limestones, which they re-
semble in a fracture. ‘Their change in bulk is similar
to that of the poor limes.
The differences in chemical composition, which pro-
duce these remarkable'changes,willbe noticed further
on. But let us now consider the action of lime as a
mortar or cement in its simplest form. If a rich lime
‘be mixed up with water into a paste, and be left for
some time exposed to the air, it gradually dries up,
and there remains a'friable mass of hydrate of lime. ‘
If, however, a thin layer of this paste be interposed
between two ‘smoothly dressed porous stones, the
greater part ofthe water of the paste is absorbed by
the stones, and the thin layer of hydrate of lime sets
and adheres strongly to the stones. The absorption
of the water must not be too rapid, or the hydrate ‘
will set too quickly, and in such case not become
hard; hence the two dressed surfaces of the stone
should be wetted before the lime is . applied to them.
The adhesion between the hydrate of lime and the
stone is greater than the particles of the hydrate
among themselves, hence the layer of hydrate should
be very thin. A much firmer . s-ubstance‘is, however,
obtained by mixing with slaked lime two or threetimes
its weight of quartzose sand, .or any pounded stone, I
and well stirring up the whole with water. This ?
mixture is spread by means of the trowel over the
surface of the stone, and the other stone is placed ' formed into mortar, have a cubical content of 315 feet.
upon it so as to press out the-excess‘ of mortar, and
leave only a thin layer.
sand is enveloped in a pellicle of lime which adheres
to itstrongly, and has the further advantage of pre-
venting the mortar from contracting too much in
setting, which contraction would cause the mortar to
form numerous fissures, and to become‘ friable. The
setting of the mortar does not depend solely on-the
evaporation of the water, but also on the combination
of the lime with the carbonic acid of the air. Those .
portions of the lime which are in contact with the air become converted into carbonate of lime; but the;
interior parts form a combination of carbonate and;
A great length of time -
is, however, necessary for the complete formation of .
hydrate of great hardness.
this compound, for after the lapse of many years, the
lime still exists as a hydrate in the thickness of the .
walls. General'Treussart-vfonnd in 1822, in demolish- -
ing one of the bastions in the citadel of Strasburg,
erected. by Vauban’ in 1666, that. the lime was as soft
as if it had been only just made. Dr. John also states, '
that in taking down a pillar, 9 feet‘ in diameter, in the churchof St. ~Peter at Berlin, which had been erected j
80 years, the mortar was found to be perfectly soft in _
the interior. Hence it will bescen that this kind of
mortar ought not to be. placed in thick walls where it
cannot possibly dry.
In such case, each grain of‘

Itfis'admitted, that quartzose sand, mingled with
lime, exerts no chemical action; for if the solid mortar
be dissolved in an acid, silica does not separate in
a gelatinous state, which it would do if the sand
were only partially in combination with the lime in
the form of a silicate. _
‘Thequality of the mortar depends greatly on the
mode in which it is prepared, on the quality of the
sand, on‘ the quantity of water with which the lime
has been slaked, and also on the greater or less per-
fect mixture of the materials. A rough sand is pre-
ferable-to a smooth grained sand, and in all cases it
is desirable that the mortar set slowly. It is even
stated that mortar assumes a greater solidity in
autumn or winter than in the warm. weather of sum-
mer, 'when ‘evaporation is rapid. The sand usually
preferred has a sharp grit, and the proportions in
which it is used in different districts vary with the
quality. The mortar for. ordinary constructions con-
sists of 1 part stone-lime and 3 of sand: the sand is
made into the form of a basin, into which ‘the lime is
thrown in a quick state; water is then thrown upon
it to slake it, and it is immediately covered up with
sand: after remaining in this state until the whole of
the lime is reduced to powder, it is worked up with
the sand, and then passed through a wire screen,
which separates the core or unslaked portion of the
lime. That which has passed through the screen has
more water added to it, and it is well worked up or
ferry/ed for use; In some cases the lime is placed in
the middle of the heap of sand, and after water has
been thrown out, it is well worked up. with hoes: in
a few hours‘it sets,'and is fit for'use. By this method
lime‘ takes up more sand than in the former: 72
bushels of good stone-lime, and 18 yards of sand, when
‘The mill for mixing mortar consists of a vertical
spindle, to which a millstone is attached, and revolving
on an iron bed, upon which the limestone or chalk-
lime to be pounded is thrown. - Curved pieces of
iron, called mines, are attached to the shaft, and by
their revolutions keep the bed free. The lime being
properly ground, is passed into another mill, where it
is mixed with sand, and triturated by means of revolv-
ing rakes, attached to the arms of a horizontal wheel;
moving round in a circular bed. Pug-mills, similar to
those described under BRICK, are also used.
Common mortar, made with rich lime, is not only
used with hewn stone and brick, but also with rubble-
work, small fragments of stones being placed in the
large interstices to diminish the bulk of the mortar.
Flint stones are also introduced so as to project, and
thus prevent the mortar from being rubbed or worn.
In dry places, ordinary mortars made with rich lime
are a considerable time in solidifying‘: in moist places
they solidify with difficulty; and under water, as
already stated, not at all; for, in the last case, the
mortar becomes diffused through the water, and the
lime is dissolved out. For constructions in moist
places, or under water, hydraulic mortars are employed
which solidify by virtue of a special chemical action,
, which we have now to consider.
300
MURTARS *‘AND 'CEMENTS.
"strongly calcined.
The phenomena exhibited on slaking a pure or rz'c/r
lime, have been already stated under (1). When, how-
ever, the limestone contains more considerable propor-
tions of foreign matter, its properties become changed
in a remarkable manner. If the limestone contain
oxide of iron, manganese, or quartzose sand, it yields,
by calcination, a lime which, when slaked with water,
swells but little; and does not form a binding paste.
vThis slaked lime hardens in the air in the course of
time, but .becomes disintegrated in the water. If,
however, the. foreign matter mixed with the carbonate
of {lime be‘ clay, or .even silica in a certain state of
division, andin the proportion of at least from 10 to
15' per cent; of the weight of the carbonate, the lime
produced by its calcination'isstill poor, but it pos-
sessesithe.property. of solidifying under water in a
longer or shorter time, provided it has not been too
This constitutes lzy/clmulic lime,
and its setting depends on a chemical combination
between the- lime and the silica of the clay.1 ' A few
experiments will show the mode in which the clay
and the silica act in order to communicate this
property to the lime. If milk of lime and clay, dried
at a temperature of between 600° and 800°, be kept
for some time in a stoppled bottle, the clay abstracts
water from the lime, and the water no longer restores .
to rcddenedl litmus paper its blue colour. If the clay
be replaced. -by gelatinous‘ silica, the latter also ab-
stracts the‘ Waterfrom the clay, but with less energy.
The hydrate of alumina also takes up a little lime, but
magnesia, oxide of iron,.oxide of manganese, do not
do so sensibly. This experiment shows that alumina,
silica, and especially clay, have such an affinity for
1ime,'as to] take it up even from water, and to fix it
inthe form of an insoluble compound; whilst magnesia

(1) Although hydraulic limes were known to the Romans, and
cannot be said to have been lost sight of since the time of
Vitruvius, yet no attempt was made to ascertain their composition
and the reasons which enabled them to set under water until the
time of Smeaton, in 1765. While engaged in the erection of the
Eddystone Lighthouse, he wanted a. cement that would harden at
once. under water, and accordingly he undertook a. series of
experiments for. the purposc,.and soon arrived at the conclusion,
“that all the limes which could set under water were obtained
from the calcination of such limestones as contained a large
-portion of clay in their coinpositiom” and he further states,
“that it remains a. curious question, which I must leaye to the
learned naturalist and chemist, why an intermediate mixture of
clay in the composition'of limestone of any kind, either hard or
soft, should render it capable of setting in water'in a manner no
pure lime I have yet seen, from any kind of stone whateverhhas
been capable of: doing.” The legacy which ourv illustrious engineer
thus bequeathed to the "learned naturalist and chemist,” notwith-
standing’ someinéguiries after‘it by Guyton d e Morveau, Bergman,
Saussure, and Colets Descotils, remained uninherited until the
year 1813, whenv M. Vicat instituted along and laborious inquiry,
which terminated in placing the sc ience of Mortars and Cements
on a sure basis. The subject has received a good deal of attention
. from‘ other chemists, especially the French, who have made it‘
almost-their own‘. The reader who desires to study it,_. will do
well to consult’ the following works :-—Treatise on Calcareous
vMortars ~and 'G'emen’tsy- artificial and natural, by L. J.‘ Vicat.
vTranslatedlbyrCaptain,L'IKSmith, 8v-o. London, 1837. >- Nouvelles'
I Etudes sur,1es,,’.‘l?0nzzolanes Artificielles, ‘par L. J. Vicat, Ato-
_ Earls; 1846. Marine} 'dufChaufournier, in the Encyclopedic-Beret,
16mm Pari's', i833; ‘enemas, ‘Chimi'e applique-e aux Arts, liv. v.‘
f chapiyiin '.B.egn‘,é.uIt,ICours de Chimie, tom. ii. 1849; Payeb;
,@hirnie-,Industriellb, 185,1; andfMr. Burynelllsl Treatise on Limes,
Cements, Mortars, Coilcretes, l&c., published In 1850, in Weale’s
Rudimentary Series. ' - ' ' ' a - ;

and oxide‘ of "iron do not possess this ’ property; and
silica, in the form of quartzose sand, is also inactive.
-If- gelatinous silica,'dried into a powder, be mixed
with lime and stirred up with water, and then be left
for some time to itself, a portion of the lime combines
with the silica; for if the mixture be treated with an
acid,'a portion of ‘the silica separates in a gelatinous
state, proving that it was in combination with the lime.
- If a very intimate mixture of carbonate of lime and
clay be carefully heated, a substance is - formed which
hardens in the 'course‘o‘f time under water. In this
substance the limevexistsxfor the most part in com-
bination with SillCEtlZGxOf‘ alumina, for it is only partially
soluble in water; and'if the‘ solution be made by means
of a weakacid, thereis a'residue of gelatinous silica:
hence clay on being heated in‘ contact with carbonate
.of lime acquires the new property of being acted on
by acids.
These experiments show that the solidification of
the hydraulic limes under water arises from a com-
bination of the hydrate of lime and the silicates of
alumina and lime, a combination which determines a
new state of aggregation of the mass, while it brings
the lime into a state in which it. is insoluble in water.
A limestone containing silicate of alumina or silica
in a state of ‘minute division, brings the silica after
calcination, or at the moment when the hydrate is
formed by the addition of water, into contact-with
the lime at‘ a multitude of points, so that the silica
itself,'now hydrated, acts the part 'of an acid, and
unites with lime‘ as a base, thus forming silicate of
lime, which in its turn combines with the silicate of
alumina and with a certain proportion of hydrate
of lime thus rendered insoluble. Since silica. has
been regarded as an acid, the chemist has been-able
to ‘explain a large number of phenomena, .which
‘embarrassed or misled earlier inquirers.
There are certain intimate mixtures of limestone
and clay, called argz'llaceous Zimest‘mzes, which by calci-
nation yield a hydraulic mortar without the admixture
of any other substance: it sets under water with
great rapidity, and becomes very hard in a short‘ time.
The term cement has been applied to this kind of
mortar, and it appears to have been first introduced
by Mr. Parker 'of London, who in'1'796 took out a
patent for the manufacture of what he‘ called Roman
cement’ from the‘ nodules of septaria found in' the
London clay formation in the Island of Sheppy. The
stones were ~lorbken into fragments, calcined "at arhigh
temperature approaching -" that vo'f - vitrification, and
then reduced* ‘to ‘powder ‘by 'cr‘ushingi and grinding.
It was afterwards discovered by 'Mr. Frost that the
septaria of -~Harwichf'produced a similar cement,- and
Atkinson'jfound that the nodules of the argil-
'laceoiis'i-Ilimestones-“of the secondary formations of
‘Yorkshire-‘could alsobe used for‘ the manufacture of
a similar material was" found at
Boulognejand‘afterwards at Pouilly" and Vassy in
iand'relsewhere'. ‘0 It is now found ‘the
‘Isle’ of Wighi5;'~7‘in “the my ‘ of ' Weym outh; # and- may
- “meet-‘premium?aetfwimin all ‘the marl bedsfwhich
occur in limestone formations, and-alsofiirthetertiary
MORTARS? AND CEMENTSL'. 4' ‘
301'
clays ;in the form of "detachednodules of a dark-
coloured argillaceous limestone, traversed by veins
filledwith calcareous spar. .When the nodules are
obtained from the has the colour may be blue; but-
in the tertiary formations brown or deep red, from the
presence of. oxide of iron.
It has been found by experiment, that a limestone
does‘ not possess hydraulic properties unless it con-
tains at least 10 or 12~ per cent. of clay. With this
proportion, the lime produced from it by calcination
on being slaked with water solidifies in moist places,
or under water, in the space of about 20 days. The
hydraulic properties are much more marked when the
limestone contains from 20 to 25 per cent. of clay:
the resulting lime on being mixed with water, sets" in
two or three days. A Roman cement, however, such
as will set in a few hours, can only be produced from
a limestone which contains from 25 to 35 per cent. of
clay. The clay (silicate of alumina) should be in a
state of minute division, and the silica be but loosely
combined with the alumina: indeed, the clays best
adapted to the purpose, give up a portion of their
silica to a solution of caustic potash.
The. following analyses of some of the most im-
portant argillaceous limestones adapted to the manu-
facture of hydraulic mortars and cements, will serve
to guide the inquirer after these valuable substances
in new localities. _
1. Argz'llaceous limestones (f moderate hydraulic
power.



From
‘ St. Germaine.
From Macon. (Aim) From Bigna.
Carbonate of lime........... 89'2 85'8 83-0
magnesia 3'0 0'4 2 0
-——————-- iron 0'0 6 2 0'0
Clay or Silica. 7'8 7 6 15 0
1000 100'0 ioo-o
2. Aryz'llaeeous limestones of great hydraulic power.
From Lezoux.
From








From Metz. Senouches. Don-1e.)
Carbonate of lime........... 77'3 80'0 72'5
magnesia 3'0 1'5 4'5
iron 3'0 ‘ 0'0 0'0’
——._—- manganese“ . 1'5 0'0 0'0
Clay or Silica ._ ............. .. 15'2 18'51 23'0
1000. 100-0 100-0
3. Clement Slorzes.
From ~ ~
Pouiily. From
From From \Coze Argentcuii,
Boulugne. London. d‘Or.) near Paris.
Carbonate of lime........... 63'6 65'7 57'2 63'0
magnesia 0'0 0'5 3'6 4'0
—- iron 6'0 6'0 6‘6 0'0
manganese. 0'0 1'9 0'0 0 0
23-8 24-6 25'2 27'0
WVater . 6'6 1'3 7'4 6'0
1000 1000 1000 1000
When 'the'limestone contains more than 30 per cent.
of clay, it no longeryields a cement by calcining, and
the paste formed with water is not sufficiently binding.
The calcination: of hydraulic limestones, and especially
of cement stones, requires certain precautions. If the
temperature be too high, the combination between the
lime and the silicate of alumina becomes too intimate;

(I) , Silica only, in a minutely divided state. ‘

there is an aggregation of the particles, and a new’
combination is not formedion the addition of ~ water.‘
The heat ought to be only just sufficient to deprive-
the limestone of the greater part of its carbonic acid,"
and the clay of its water. The cement stones ‘are
burnt in conical kilns with running fires, and in
England with coke or coal. The stone loses about-
one-third of its weight by calcination, and the colour‘
becomes modified according to the chemical constitu-
tion of the stone. The stone may be preserved for a
long time without change in a dry room; but as it
cannot be used in this form, it is ground at a mill,
and packed in tight casks in order to preserve it from
contact with the atmosphere until required for use;
for if exposed, the powder absorbs moisture and car-'-
bonic acid, and would require a second calcination at-
a lower heat before it could-be used. The sp. gr.
of the stone is about 216; that of the calcined stone-
in block about 1'58; and that of the powder loosely
packed. about 085 to 100. The lightest and finest
powder forms the best cement. The French engineers‘
use a sieve for sifting the powder, in which 185 meshes
go to the square of four inches of a side.
is required iii mixing the powder: if too much. or too
little water he used, or if not vapplied as soon as made,
it solidifies unequally, cracks, and adheres badly.
The proportion of water. should be about -,1.;d of the-
cement in volume: it shouldbe well beaten up, and-
if new and of good quality, it will set in five or .six{
minutes, or under water in an hour at: most. ‘If sand.
be added, the setting is retarded. When mixed with.
sand in proportions varying from ,1; to 1,1% and 2 to "
1 of cement, the time of setting becomes 1 hr. 2 1nin.=
to 1 hr. 18 min. in the air‘, and much longer under.
water, and even 241 hours under sea-water. The pure
cement is much stronger than when mixed with sand.
The resistance to rupture offered by pure cement,-
after about 20 days’ exposure, is about 54ilbs. per
inch square: if sand be present in the proportion of'
g to 1 of cement, the resistance is 37 lbs. ; ‘and if in
equal proportions, only 27 lbs. Thus it will be seen
that, while pure lime increases in strength by the.
addition of sand, hydraulic lime, on the contrary,
deteriorates.
that finely-divided silica and clay are . not. the only
substances that impart hydraulic properties to limer
A certain proportion of magnesia produces the same
effect, although in a less degree. Thus it is found
that certain magnesian limestones, dolomites for ex-.
ample, yield‘ by calcination hydraulic limes of inferior,
quality; and their action is due to a chemical combi-
nation formed, when water is present, between hydrate
of lime andhydrate of magnesia. It is even stated
that a very intimate mixture of quicklime and carbo—
nate of lime has feeble hydraulic properties; and lime-
stone gently heated, so that a large portion of it
remains in the form of carbonate, is slightly hydraulic.
In the burning of rich limes, imperfectly burned
fragments are always found, which have this charac-
ter ; and it appears to be due to the formation of a
definite compound of carbonate of lime and hydrate
of lime, GaO,'COz-i—CaO,HO.
Great care .
It will be seen from the analytical list,
302
MORTARS" AND‘ CEMENTS.
Hydraulic mortars are formed artificially by cal-
ciuing intimate mixtures of rich lime and clay. Some
extensive-works of this kind were erected at Mendon,‘
near Paris, under ,the superintendence of M. Vicat.
The chalk, whichis broken'into. lumps the size of the
fist, is ground with clay,.in the proportion of 4.‘ parts
chalk to 1' of clay, in a, large vertical mill, withv a
plentiful supp1y__0f'water: the liquid mixture is run
off into a series of five troughs placed at different
levels, and in them > the matter held in suspension: is
deposited‘. ; A double set ‘of troughs is required,- for
while one setpis ' being filled,‘ the matter is subsiding
in the other. The subsidence is more rapid in shallow
than in deep troughs. When the subsided matter is
sufficiently firm to be handled, it is moulded into
small prisms :1 these are placed upon a drying plat-
form, and when. of the consistence of freshly-quarried
limestone, they are burned in a kiln. '
‘ A somewhat'similar plan is adopted in England in
the manufacture of what is termed Portland ' cemezzt,
which‘ is, in fact, an' artificial hydraulic lime, com-
posed of the clay of the valley of the Medway, mixed,
in certain proportions, with the chalk of the same
district. The materials are thoroughly‘ ground up
together with water, deposited, dried, and burnt ; but
in burning the‘ heat is urged as far/‘as the point of
vitrification: the lime is in fact overburnt, and often
irregularly so.' Hence, much care is required in
grinding up the diiferent products of the calcination,
“to make them: regular in their times of setting; for
all 'overburnt‘ limes, as well as natural cements, slack
with. difficulty ’in- masses, and require to be broken up
or groiuid to powder before being used. Portland
cement also permanently expands in setting, so that
it should not" be used in positions where this property
may interfere with the solidity of the work. It is of
great valuein external plastering.
The extraordinary'tenacity of Portland cement was
well illustrated by some experiments at the Great
Exhibition, and noticed at length in the‘ Jury Report,
Glass xxvii. ' In one of - these experiments 2 six-inch
cubes of Portland stone had about 4: months previously
been cemented with about -,1,-_th inch thick of Portland
cement. The upper stone being held by iron clippers
the weights weresiispended from the lower one, the
depth of the holesf forthe clippers being éths inch.
When the weight amounted to 3,780 lbs. the former
broke. The square holes for the clippers being made
deeper in another part of the stone, and the scale
being‘ once more loaded, the iron hook by which the
scale was suspended broke at 4,5 80 lbs. the cement
still remaining perfectly sound. In this experiment,
therefore, the "strength of the cement was not abso—
lutely'te's‘ted. ' ‘1 .
Yb‘lock'of neat Portland cement 16 inches long .
'a'iid'd inches square, was suspended from each end, .-
Flildtllfi weight applied in~ the centre. It broke at 1,5801bs. ‘with. a‘ perpendicular, even, and good‘ frac- j
ture.~ "The block had been made 4: months. A i

__ (‘1)"8'0 called’froni its'appmaching ‘in colour to Portland stone, i
not‘from being made of the stone, or in any way connected with .
the Isle of‘ Portland.

similar block of neat Roman cement made from Ear-
wich stone, and 7 weeks old, broke at 380 lbs. ; but
it is remarked that this must have been a bad
sample.
Several beams were made of bricks joined together
by Portland cement. A beam one month old made
i with 16 ‘common stock bricks joined by very thick
intervals of real Portland cement, on being held at
the extremities,» broke with a weight of 500 lbs. hung
from the middle. The part. broken was the brick only.
A similar beamihaving one end only supported, and
projecting 3 feet 2%— inches from the bearing point,
i was weighed and. broke with? 256 lbs. exclusive of the
scale, suspended from the free extremity. The frac-
ture took place at the eleventh brick from the fixed
end, and both brick and cement were fractured.
The resistance of Portland cement to crushing
weights was also remarkable. A blockof this sub-
stance 30 days old, measuring 18 inches x 9 X 9,
was tested by a Bramah’s hydrostatic press, and is
said to have withstood a pressure of 41 tons for up-
wards of a minute, when it broke up with a report.
A similar block of 1 part cement and 1 sand, 28 days
old, crushed at 108 tons ; 41 sand and 1 cement, 45
tons; 9 sand and 1 cement, 4% tons.
It is stated in this Report that upwards of two mil-
lions of bushels of Roman cement are made every
year from the material obtained from the coast near
Harwich, and that the price is from 308.- to 4:08. per
ton. What is called Medina cement is made ‘from
the Hampshire septaria. Aflcz'vzson’s, or Mulgmve
cement is made from the has and some other rocks.
Hydraulic mortars are also prepared by mixing a
rich lime with baked clay, or with certain volcanic
substances to which the name of puozzolmzo has been
applied, from Puozzoli, near Baia, not far from Vesu-
‘vius, from which the Romans obtained material for
making mortar. A similar material has been found
in the Vivarais, a theatre of extinct volcanic action
in the centre of France; also near Edinburgh; at the
village of Brohl, near Andernach, on the Rhine, where
: it is called trass, or termss; and in other places where
subterranean fire has been exerted. It varies greatly
' in appearance: it is found in powder, in coarse grains,
fin the form of pumice, scoria, tufa, or small rubble-
stone; and it may be brown, yellow, grey, or black,
all these colours sometimes occurring in the same
locality. The puozzolanos chiefly consistiof silica ‘and
alumina, combined with a little lime, and mixed with
potash, soda, magnesia, and oxide of .iron, the latter
capable of ‘ afi’ecting the magnetic needle. According
to Berthier, the trass of Anderna'ch‘ and the puozzo-
lano of Civita-Vecchia consist of—


Trass. Puozzolano
Silica . O 570 0'445
Alumina................... 0-120 0150'
Lime 0-0261 , 0'088
Magnesia . 0-010 0-047
Oxide of 0050 0-120
- Potash...................... 0-070 0014
0010 0040'
Water.............. .. 0'096 0'092
0-952 0-996
MORTARSY AND; @EMENTSJ -
803?
Basaltic and trap rocks. behave in the same manner
as the puozzolanos 5 but the difficulty of reducing
them to powder precludes their adoption as ingre-
dients in hydraulic mortars. But it is found that
most burnt clays, if not too highly calcined, answer
the same purpose, and that good artificial puozzolanos
may be formed by reducing to powder common bricks,
tiles, and pottery-ware. '
The chemical reaction which takes place, by which
a mixture of rich lime and puozzolano acquires
hydraulic‘ properties, is illustrated by the following
experiment :—A common brick left for some time in
lime-water, becomes covered with a pellicle of caustic
lime, which is insoluble in water. If puozzolano in
fine powder be left for some days in a bottle of lime-
water well stoppled, it takes up the whole of the lime,
and the water no longer exerts any alkaline reaction.
Hence puozzolano has a strong affinity for hydrate
of lime, and hydraulic mortar made with powdered
puozzolano and lime, sets under water, and becomes
insoluble in consequence of the aflinity existing
between hydrate of lime and puozzolano. That the
compound thus formed is extremely hard, is evident
from the Roman remains, which still exist for our in-
struction. The mortar is in many cases more solid than
the brick, for while this has receded by wearing away,
the mortar projects beyond it. .
Corzcrez‘e and be’z‘on belong to the class of mortars
now under consideration. _ They are formed by mixing
gravel or broken stone with lime, which may or may
not have been previously worked up into a mortar.
Concrete is valuable for the backing of coursed
masonry, where walls are required to be of great
thickness, and also in foundations and underground
works, where it is confined on all sides, and not sub-
jected to much cross strain; but it ought not to
be used aboveground as a substitute for masonry.
The lime should first be made into a hydrate or
mortar before mixing with the pebbles. For water
works required to set rapidly, a mixture of hydraulic
limes, puozzolanos and sand may be used. The fol—
lowing proportions are ,reccmmended by Treussart :—-
30 parts strong hydraulic lime, measured in bulk before
being slacked.
30 parts trass of Andernach.
30 parts sand.
20 parts gravel.
40 parts broken stone, a hard limestone.
These materials diminished one-fifth after being
worked up. The mortar was made first, and the
stones and gravel added. This concrete must be
used as soon as mixed. l/Vhen the puozzolano of
Italy is used, the proportions are :—
33 parts strong hydraulic lime measured before slacking.
45 parts of puozzolano.
22 parts of sand.
60 parts of broken stone and gravel.
This concrete to be exposed 12 hours before it is
used.
A good concrete for sea or river works, is made by
a mixture of a mortar made of 3 parts of fine sand
to 1 of hydraulic lime unslacked, with equal quan-
tities of gravel or broken stone, but the latter may }

'be increased in the’ proportion of 135 to 1 of the
mortar. No water should be mixed with the mortar
and gravel during the mixing, and clay and other
earths should be carefully excluded. This concrete.
should be spread in layers from 10 inches to 1 foot Y‘
in thickness, and well rammed.
The stones used in concrete should be angular
rather than rounded, so as to form more easily a
solid mass. The usual material is unscreened gravel,
which contains a good deal of sand, and large and'
small pebbles. Small irregular fragments of stone,
granite‘ chippings, are of great use in bonding the
mass together. The proportion of lime and sand
must depend on the quality of the lime, purer limes
requiring ,a' large proportion vof sand, while the stone
limes, a smaller quantity. This kind of concrete
undergoes a slight permanent expansion before
setting, which makes it valuable for underpinning
foundations, and similar purposes; but it should not
be exposed to water, or the limewillbe washed out,
and the concrete left in the state of loose gravel. In
this way some writers distinguish‘ concrete from
béton, the former not standing water, and the latter
being eminently hydraulic. According to this, view,
concrete is made with lime, andbéton with hydraulic.
lime. Béton “differs from ordinary concrete, inasmuch
as the lime must be slacked before mixing with the
other ingredients, and it is usual ‘to make the lime
and sand into mortar before adding the stones.;._-; Con-
crete also is used hot, while béton is allowed to; stand
before being used, in order to insure the ‘perfect
slacking of every particleof lime,”‘ Béton is chiefly.
used in submarine works as a substitute for masonry
in situations where the bottom cannot be laid dry.
It is lowered into the ‘water in a box, with ahbottom
so constructed, that itcan be opened by pulling a
- cord when the béton is discharged, in the exact spot,
without having to fall through the water, ‘which
might wash away the lime. '
Cements made from sulphate of lime or plaster of
Paris are very numerous.2 This substance forms thev
basis of K68726'8,‘M617‘fi72’8, Purim, and other cements.
The plaster, in fine powder, is mixed with a saturated
solution of alum, sulphate of potash, or borax, then
dried in the air, and afterwards baked. at a dull red
heat. It is again reduced to powder, and sifted, when
it is fit for use. It is ,slaked with a solution of alum,
instead of pure water. This forms .K66726’8 cement.
When borax is used, it is called Parz'mz. Marzfz'rz’s is
made with pearlash as‘ well as alum, and is baked at
a higher heat than the others. Stucco is a combina-
tionv of plaster of Paris with a solution of gelatine or
strong glue. The mixture dries more slowly than
when made with water, but is more durable. Seayliola
is prepared from the finest gypsum: the sifted plaster
powder is mixed with alum, isinglass and colouring
matter into a paste, which is beaten on a prepared

(1) Treatise on Foundations and Concrete Works, by E. Dob-
son, C.E., published in Weale’s Rudimentary Series.
(2) The ornamental varieties of sulphate of lime, such as ala-
baster, together with the methods of preparing and using plaster
of Paris, are described under Grrsmr. See also LIME.
304.
MORTARS AND‘ GEMENTSQMOSAIC.
surface, with fragments of marble, &c. The surface pre-'
pared for it has a rough coating of lime and hair. The
coloursare laid on andmixed. by hand somewhat after
the manner of fresco. [See Fnnsco-Parnrrnej Sac. .
cessv depends on the skill of the operator in imitating
the style, beauty, and veining'of'the Imarble to be
imitated. ' When the- cement has been properly laid
on and hardened,- the surface-is rubbed with pumice-L
stone, and cleaned with a wetsponge. It is then
polished by mbbing first with tripoli and charcoal,
then withlfelt dipped ‘tripoli' and oil, and lastly with_
oil alone. --This3le'aves~a durable polish ‘equal to that.
of marble. Indeedgthe material is as hard as marble,
cold to ‘the'touchpiandi'very durable. '- It is, in fact, an
artificial. stone, and vproperly ‘belongs to our article on
that subject. [See Brown-1 -
A metallic sponge ccrzenfforpave'ments was exhibited
by M. Chenot, It is prepared‘ by reducing certain.
ores of iron (oxides) into a spongy state by the, removal
of oxygen gas,‘ in which condition they form av durable
cement. ' l ‘
MOSAIC, laborious mode of forming patterns
or devices with minute pieces of differently-coloured
substances strongly cemented together. ‘This was
the Opus Zllusz'vum of the Romans, of which many
interesting specimens remain in the costly tesselated
pavements of that people. Wherever their empire
extended, traces of this art vare from time to time-
-; discovered, some of these are of ‘the most elabo-
' ‘rate description. ‘At a little village near‘ Seville, ‘an
extraordinary specimen was dug up in 1799, forming
a pavement 40 feet long and 30 feet broad, and
representing in the centre the circus games, with a
variety of figures, horses, chariots, &c., surrounded
by a fanciful border, with circular compartments con-
taining figures, of the Muses. This is supposed to
have belonged-‘to-rthe hall of the baths of a palace
constructed pl‘iQl‘i-"lZO the reign of Domitian, A. 1). 8L
Another beautiful mosaic pavement was discovered
at Lyons iii-1806, while numerous examples occur in
own country.
Thejinateri'alsdcr mosaic-work are marble, stone,
plaster,~ enamel, wood, &c., but they may also be glass
or precious stones. The walls of buildings- as well
as the floors were thus decorated from a very early
jhvzperiod ; and at length, at the commencement of the
517th century, by the use of exceedingly. minute
pieces, pictures were successfully copied, the various
shades and colours being imitated in thousands of
pieces" of enamel. The artists of Rome are deservedly
celebrated/for mosaic pictures. A portrait of Pope
Paul the Fifth, executed in this manner, is said to
consist of one million seven hundred thousand pieces,
each ‘5110 larger [than a grain of millet. The Roman
mosaic does not consist of stones like that of Flo-
rence, but of an enamel artificially prepared, being a
kind ‘of glass coloured. with metallic oxides: of these
colours, there are said to be from 410,000 to 50,000
shades.‘- ‘ ' r
This enamel is so fusible that‘ it can be easily‘ drawn
out intothreadm'small rods, or oblong sticks, of vary-
ing degrees of‘: fineness,‘ and-somewhat resembling

compositor’s type. These rods are arranged in cases
or drawers, properly labelled, so as to be ready to the‘
artist’s hand when required. In order to commence
a-mosaic picture, a piece of copper, marble, or slate,
of the necessary size, is taken and hollowed out to
the depth of about 3% inches, leaving a border all
round whiclrwill be on a level with the future
picture. The excavated surface is intersected by
transverse grooves, the better to retain the cement
which) is to bewplaced therein. The hollow is first
vfilled*vvith Pplaster-of-Paris, well smoothed, on which
'the‘iprop‘o'sed design is accurately traced in outline,
andtthe latterstrengthenedv by means of pen and ink.
The‘ mosaic work. is commenced by scooping out with
a tool a small portion of the plaster, putting a portion
of mastic "or cement-in its place, and then inserting
the pieces of glass or enamel according to the pattern.
This cement, or mastic, is of a very strong and durable
‘kind, which ultimately becomes as hard as flint : it is
this which makes it necessary to fill the excavated
bed 'of the stone by degrees, as the work proceeds,
and not‘ to put a larger quantity than can be employed
~while soft. iMeanwhile the tracing on the plaster-of-
;Paris is _‘-interfered with as little as possible.
times, on the portion of mastic inserted, a part of the
Some-
picture about to be executed is delineated in the
same way as in fresco painting, after which the frag-
ments'of ‘enamel, selected according to their colour
and gradation of tint, are driven in by means of Va
small wooden mallet. If the efiect does not please
the artist, ‘he can easily withdraw certain fragments
and substitute others while the cement is still fresh.
By observing proper‘ precautions an artist may keep
the enamel moist for upwards of a fortnight. When
the whole work is completed, ‘any crevices which may
exist are stoppedi'with pounded marble, or with ena-
mel mixed with wax,» and the surface is ground down
to a perfect planeipolished- with putty and oil.
The grinding- and are‘laborious-works; in-
deed, the whole procéssiiof, forming afp'licture in mosaic,
requires great patience,‘ as‘v well as skill, in the opera.
tor, for if the}?
years in the eieeniiien. . I} ,
The works in ‘mosaic at the Great Exhibition well
maintained the high reputation of Bottle." A. mosaic table, representing many of
Italy, was exhibited bytheinventor and-artist, the
Cavaliere Parberi, and was ‘a' specimen of rare taste
and wonderful execution. .
A series Qfbeaut'iful mosaics by the Cavaliereliuigi
Moja, representing a wild boar-hunt, a view‘ ' 9f; the
Great Piazza of S’t-Peter’s at, Rome, the Colosseum,
Pantheon, 859,,’ were also of high merit, as was like
wise a Roman mosaic‘ representing the Temples of
Pa'es'tum at sunset, by Antonio Rocchigiani. Some
remarkably fine specimens were also sent from the




IRo'yal =htlfanufactory at 'St‘.'Peter’s, Rome, of a larger
description of mosaic, intended to be viewed from
& distance-3,1 ‘the Colours and drawing of which‘ were
perfect. ~ ~ A? beautiful example of Florentine mosaic;
being a-tableeinlaid with various stones, was sent from
the ImperialPolishing Manufaetory near .St. Peters-
. \ _ _‘
igbelllmgei It may take several-
MO SAICe—MOTHEROF-PEARL.
305
burg,- and helped to grace the Russian department of
the Exhibition. Florentine mosaic‘ is essentially inlaid-
work in gems, or pseudo-gems, such as agate, jasper,
chalcedony, cornelian, &c. A slab of marble about
;%7th of an inch thick, and generally black, is prepared,
by carefully cutting - out with the. saw- and file the
patterns to be‘ inlaid. The gems are then cut and
accurately fitted to these patterns in their-polished
and finished state, for this kind of mosaic cannot, like
the Roman mosaic, be ground and polished as a whole,
because the ‘substances used are of unequal hardness,
and some of the stones would be worn away too
rapidly. The greatest nicety is required in placing
the stones, so that one shall not ‘be in the least degree
lower than another ; a mistake of this kind is sufficient
to ruin the whole. After the surface is thus prepared,
it is veneered on a thicker slab, and is then fit for use.
The Russian table just alluded to, was inlaid with
jaspers and other stones from Siberia: it was of ex-
cellent workmanship, the produce of a manufactory
where the workmen were all originally Italians, but
where the art is now successfully practised by Rus~
sians. Some specimens of perhaps greater merit
were sent from vTuscany, the stones consisting of
pebbles from the Arno.
A third kind of mosaic has been introduced in Eng-
land and elsewhere with good effect, and is now
becoming known as Derbyshire mosaic. It is formed
by replacing the jasper and agate of Florentine mosaic
with marbles of various kinds, shells, cement,‘ and
glass. The latter substances have, in general, been
too profusely used—giving brilliancy indeed, ‘but not
according with the principles of good taste. There
were many interesting examples of this kind of mosaic
in the Great Exhibition, chiefly table-tops ‘ beautifully
inlaid. From Derbyshire, 'Mr. Vallance exhibited a
table on which was wrought a ‘most. complicated and
admirably finished wreath of flowers.‘ Several other
Derbyshire manufacturers also sent beautiful speci-
mens. From Devonshire some very fine specimens,
especially a table by Mr. Woodley of Torquay, illus-
trated the'beauty of the marbles in that county, and
the advancing skill of the manufacturers. 'The follow-
ing remarks on Derbyshire mosaic are from the Jury
Report, p. 568:-— '
I “ To a very limited extent, and by a very rude
method, the art of inlaying in marble was practised in
Derbyshire many years ago; but within the last
quarter of a century it has made great and ‘rapid
advance, and about ten years since, the introduction
of Florentine patterns, imitated in various coloured
marbles, has exerted a very important influence on the
trade. The first manufacture of mosaic in Derby-
shire consisted of coloured spars and marbles of
irregular shapes, imbedded in cement, and afterwards
rubbed down and polished; these were called ‘ scrap
tables,’ and were succeeded by slabs, in which the
spar and the marble were cut into definite forms
arranged in patterns; but these also were rudely
finished, as the workmen were not skilled in the art
of making accurate joints,’ and the forms selected
were simple and geometrical. Up to this time the
VOL. II .

process was little more than veneering, and the results
were rather imitative of brecciated marbles than in-
tended to produce pictorial effect. The present Duke of
Devonshire, by permitting his fine collection of Flo-
rentine work to serve as a guide and model to the
Derbyshire manufacturers, and even lending'them the
inlaid butterflies, leaves, sprigs of jasmine, &c., for
which the Florentine mosaics are celebrated, induced
an imitation of a higher kind. The true art of in-
laying was thus brought ‘into successful operation,
and materials foreign to the vicinity, as malachites
from Russia, continental marbles, aventurine, and
other glasses from Venice, with some cements, have
been introduced. The use of these substances greatly
diminishes the cost‘ of the work. The condition of the
trade at present may be judged of from the‘articles in
the Exhibition, which show much taste and skill,
.though but little originality. The manufacture is
carried on at Matlock, Ashford, Bakewell, Buxton,
Castleton, and Derby, and the number of persons
employed as mosaic workers exceeds 50. There ap-
pears to be a fair demand,‘ and the prices, although
sometimes high in London, are by no means extrava-
gant at the place of manufacture.”
- By some writers the works in malachite, for which
the Russian department of the Exhibition was so
remarkable, are called Russian mosaic; but it appears
to us inappropriate to apply this term to works in one
material, whereas its usual application implies a
variety of colours and materials skilfully brought
together to produce harmonious‘ effects.
MOSAIC GOLD, or 'AunuM Musrvun. See
TIN. A-recipe for making this substance is given
under Bnonzrne. -
MOTHER-OF-PEARL, or Nncnn, is the hard,
silvery, internal layer 'of several kinds of shells, espe-
cially oysters, the-large varieties of whichin the Indian
‘seas secrete this coat of sufficient thickness to render
the shell an object ‘of manufacture. The genus of
shell-fish, Perztadz'nw, furnishes the finest pearls as
well as'mother-of-pearl: it is found round the coasts
of Ceylon, near Ormus in the Persian Gulf, at Cape
Comorin, and in some of the Australian seas. The
dealers in pearl-shells consider the Chinese from
Manilla to be the best : they are, fine, large, and very
brilliant, with yellow edges.‘ Fine large shells of a
dead white are supplied by Singapore, Common
varieties come from Bombay andValparaiso, from the
latter place with jet' black edges. South Sea pearl-shells
are common, with white edges. The beautiful dark
green pearl-shells called ear—stalls or sea-ears are more
concave than the others, and have small holes round
the margin: they are the coverings of the Halz'otz's,
which occurs in the Californian, South African, and
East Indian seas.
In the Indian collection of the Great Exhibition,
specimens of the finest pearl-shells were shown, such
as the Meleagrz'm rizaryarz'tjifiem, H alz'ot‘z's gzlgas, Hali-
otz's iris, and a large species of Turbo, which shells are
known in commerce as fiat-shells, ear-stalls, green
snail-shells, bufalo-skells, Bomtag/ shells. Messrs.
Fauntleroy and‘ Mr. Banks had also some fine collec-
x
306
MOTHER-OE-PEARL—TMUSK.
tions. The latter gentleman states thdt the shores
of the Sooloo Islands aiford the finest shells.
The beautiful tints of mother-of-pearl depend upon
its structure; the surface being covered with a multi-
tude of minute grooves, which decompose the reflected
light. Sir David Brewster, who was the first to
explain these chromatic effects, discovered, on examin-
ing the surface of mother-of-pearl with a microscope,
“ a grooved structure, like‘the delicate texture of the
skin at the top of‘ an infant’s-finger, or like the section
of the annu-algrow‘th‘s' of wood as- seen upon a dressed
plank of fir. These may, sometimes be seen by the
naked eye; but they are ‘often ‘so minute that 3,000
of them are'containe'dfin an inch.” It is remarkable
that these/iridescent hues can .be communicated to
other surfaces as a scalimparts its impress to wax.
The ‘colours may be best seen by taking an impression
of the mother-of-pearl in black wax; but “ a solution
of gum arabic- or of isinglass, when allowed to inclu-v
rate upon a surface of mother-of-pearl, takes a most
perfect impression from it, and exhibits all the com-
municable colours in the finest manner, when seen
either by reflection or transmission. By placing the
isinglass between two finely-polished surfaces of good
specimens of mother-of-pearl, we obtain a film of arti-
ficial ‘mother-of-pearl, which, when seen by single
lights, such as that of a candle,. or by an aperture in
the window, will shine with the brightest hues.” 1
It is in consequence of this lamellar structure that
pearl-shells admit of beingv split into laminae for the
handles of knives, for counters, and for inlaying.
Splitting, however, is liable to spoil the shell, and is
therefore avoided as much as possible. The different
parts of the shell are selected as nearly as possible to
suit the required purposes,.and the excess of thickness
is got rid of. at the grindstone. In preparing the rough
pearl-shelhthe square and. angular pieces are cut out
with the. ordinary .brassaback saw, and» the circular
pieces, such as those for buttons, with the annular or
crown-saw, fixed upon a lathe-mandrel. The pieces
are next ground flat upon a wet grindstone, the edge
of which is turned with a number of grooves, the
ridges of which are less liable to be clogged than the
entire surface, and hence grind more quickly. If the
stone be wetted with soap and water it is less liable
to be clogged. The pieces are finished on the flat
side of the stone, and are then ready for inlaying,
engraving, polishing, &c. Cylindrical pieces are cut
out of the thick part of the shell, near the hinge, and
are rounded on the grindstone preparatory to being
turned in the lathe. The finishing and polishing are
described in the third volume of Mr. Holtzapffel’s
excellent work on “ Mechanical Manipulation.”
Counters, silk-winders, 850., are smoothed with Trent
sand or pumice-stone and water on a buff-wheel or;
hand-‘polisher, and are finished with rotten stone
moistened with sulphuric acid, which develops finely
the;- ‘Striated structure of the shell. For inlaid works
theasurface is made. flat by filing and scraping; then
pumicesston'e ‘is used, :and after this putty-powder,

‘(1:)’ 'Bféwsfe'f’s v‘Optics;cher- Xiv-, one of the volumes of the
Cabinet‘ Cyclopaedia. ' a . . = , I

bothfonibufl-sticks with water; and the final polish is ‘
given with rotten stone and sulphuric acid, unless
tortoise-shell or some other substance liable to be in-
juriously affected by the acid be present in the inlay.
In turned works fine emery-paper, rotten-stone and
acid or‘ oil are used. The pearl handles for razors are
slightly riveted together ‘in pairs, then scraped, sand-
éafi'ed on the, wheel with Trent sand and water;
thirdly, gloss-defied on the wheel with rotten stone
and. oil, or sometimes with dry chalk rubbed on the
same wheel; and ,fourthly, they are handed zap, or
polished? with dry rotten-stone and the naked hand.
MOTHER-.WATER, the liquor left after a saline
solution has been evaporated so asto deposit crystals
on cooling. ,
MUCIC ACID. See GUM.
MUCILAGE. See GUM.
MUEFLE. See Assume.
. MULE. See Corron-és-Inrnonuoronr Essay, p.
cxlvi.
MUNDIC. See MINE—MINING, p. 27 2.
MURIATIC ACID. See HYnnoonLonIo Acin.
MUSK, the unctuous secretion of a glandular
pouch or sac, situated in the skin of the abdomen of
the musk-deer osc/zus mosclzg'j‘lerus), an inhabitant of
the great mountain range which belts the north of
India and branches out into Siberia, Thibet and China.
It is also found in the Altaic range near Lake Baikal,
and in some other mountain ranges, but always
on the borders of the line of perpetual snow. It is
from the male only that musk is produced, and the
secretion when dry is of a dark brown or black
colour, and somewhat granular. Its taste is bitter, and
its peculiar and penetrating odour is well known. It
was formerly held in high repute as a medicine, and it
is still so among eastern nations. The musk-deer is
eagerly hunted for the sake of its costly perfume,
which, however, is always much adulterated. Taver-
nier says that the odour of musk, when recent, is so
powerful as to cause the blood to gush from the nose,
and in this way he' would account for the supposed
adulteration of the article with dried blood. Chardin
also says, “ It is commonly believed that when the
musk-‘sac is out from the animal, so powerful is the
odour it. exhales, that the hunter is obliged to have
his mouth and nose stopped with folds of linen, and
that often in spite of this precaution the pungency of
the odour in such as to produce so violent an hzemor- -
rhage as to end in death. I have heard the same
thing talked of by some Armenians who had been to
Boutan, and I, think it is true- The odour is so
powerfulin the‘ East. Indies thatjI could never support
it; and when Itraficked for musk, I always kept in
the open air, ‘with a handkerchief over my face, and
at, a, distance from those who handled the sacs, re-
ferring them to my broker: and hence I knew by
experience ‘that musk is very apt to give head-
aches, and‘. is... altogether insupportable when quite
recent. 1 mayadjd that no drug is sodeasily adul-
terated or more apt to be‘ so.” Tavernier states that
atP'atana-he fence. bought 1,67 3 musk-bags weighing
. 2.557% ous-96$, containing 4:52 ounces ‘of pure musk-f
MUSK—MUSTARD—MYRRH—NAILS.
307
The musk from Boutan, Tonquin, and Thibet is most
esteemed; but it is probable that its strength and the
quantity produced by a single animal varies with the
season of the year and the age of the animal. A
single musk—bag usually contains from 2 to 3 drachms.
When out off it is tied up and is ready for sale.
Musk is imported into England from China in caddies
of 60 to 100 oz. each: that from Bengal is inferior,
and from Russia of a still lower quality. The best is
that contained in the natural follicle or pod. When
adulterated with the animal's blood it forms into
lumps or clots. It is sometimes mixed with a dark,
highly coloured, friable earth; the musk is then of a
more friable texture, harder and denser than genuine
musk. Previous to 1832 the duty was 5s. an 02.: in
18412 the duty of 6d. an oz. produced 53L, showing
that 2,120 oz. had been entered for consumption. In
184:6 it was declared free of duty.
Musk is very remarkable for the diffusiveuess and
subtlety of its scent; everything in its vicinity soon
becomes afl'ected by it, and long retains it: a very
minute portion, such as a grain or two, will scent a
room for years, and is suificient for imparting to articles
of dress, 850., a powerful perfume. One part of musk
will communicate its odour to 3,000 parts of inodorous
powder. Boiling water dissolves 90 parts of genuine,
Tonquin musk; alcohol only 50 parts. Musk is
soluble in ether, acetic acid, and yolk of egg.
Moisture seems to favour the odour of musk, for
when dry it yields but little scent, and this becomes
powerful when moistened. An artificial musk is pre-
pared with nitric acid and oil of amber.
Musk does not appear to have received an adequate
chemical examination.
MUSKET. See GUN.
MUSLIN. See Wnxvrnc.
MUSQUASH. See‘ FUR—HAT.
MUSTARD. A plant (Sirzapz‘s) of which there are
several species, some of which appear to be indigenous
to Great Britain. It was formerly cultivated in
Durham, but is now chiefly raised about York. Pre-
vious to the year 1720 it was prepared for use by
pounding the seeds in a mortar and roughly separat-
ing the integuments ; but it occurred to a woman
named Clements, who resided at Durham, to grind
the seed in a mill and then to dress the powder as
corn flour is dressed. The mustard prepared in this
way was very superior in quality and appearance, and
being patronised by George I. it sold largely: the
woman. kept her process secret for a time and realized
a large fortune. This is the origin of the term
Dar/mm mustard. The mustard which is cultivated
for its seeds is the Sinapz's nigm. S. alba often grows
wild among corn, and is also cultivated with the
garden cress for eating in the seed leaf as a salad.
It germinates even more readily than cress; the seeds
strewed on wet flannel or on cork floating on water
soon put out tender leaves; so that a salad may be
produced in a few days by the side of the fire in
winter.
Mustard is cultivated in the East for the sake of
the fixed oil which is obtained from its seeds by ex-

pression. By means of the cake left after this process,
an essential oil (C8H5NS2) is obtained by distillation
with water. The oil does not exist in the seed, but is
developed in the presence of water in consequence of
a species of fermentation. The cake is at first in-
odorous, but on sprinkling it with water it soon
begins to ferment, and to exhale the penetrating
odour of mustard. On distilling the cake with water
a yellow oil denser than water passes over with the
aqueous vapour: the oil is purified by a second and a
third distillation. It then becomes colourless, has a
pungent odour and a burning taste: it immediately
blisters the skin; its sp. gr. is 1015 ; its refractive
power 1516; it is very soluble in alcohol and ether;
it boils at 290°; the density of its vapour is 3'44. It
dissolves sulphur and phosphorus with the aid of heat.
The chemical relations of this oil are of interest to
the scientific chemist.
MYROBALAMS.——See LEATHER.
MYBRH, a gum-resin (containing from 60 to '70
per cent. of gum, and 30 to 40 of resin) obtained from
the bark of the Balsamodendron nag/Trim. Although
known as an object of trade from the earliest times
(for it is mentioned in Gen. xxxvii. 25), the tree does
not appear to have been known until 1825,‘ when
Ehrenberg brought a specimen of it from Gison on
the borders of Arabia Felix. Myrrh is imported from
the East Indies in large agglomerated tears of a reddish
brown or brownish yellow colour, semi—transparent,
and of a dull fracture : they have a peculiar balsamic,
pungent odour, and a, bitter, aromatic, somewhat
pungent taste. It is usually mixed with fragments of
other gums and resins. It also contains 2 or 3 per
cent. of volatile oil.
NACRE, the French word for Mornnn-or-Pnsnn.
See SHELLS.
NAILS. The forging of nails formerly gave em-
ployment to many hands in the neighbourhood of
Birmingham. Hutton, the historian of that town,
states that when approaching it from Walsall, in
1741, he was “ surprised at the prodigious number
of blacksmiths’ shops upon the road, and could not
conceive how a country, though populous, could
support so many people of the same occupation.” In
some of these shops he observed females wielding the
hammer; and on inquiring “whether the ladies in
this country shod horses,” he was answered, with a
smile, “ They are nailers.” ‘ Before the introduction
of machine-made nails, it was estimated, that in the
neighbourhood of Birmingham alone upwards of
60,000 persons, men, women, and children, were
occupied in nail-making ; and that many of the iron-
works in the same district furnished every week from
100 to 200 tons of split 2'7'022 rods for the manufacture.
These nails are termed wrought, to distinguish them
from those cast in moulds, or out or punched out of
plates of iron by machinery. Wrought nails are also
made from plates rolled for the purpose, and then slit
by means of slitting rollers into nail rods or split rods,
of various sizes and qualities, according to the variety
of nail required. For horseshoe nails the best refined
iron is required, to allow of their being drawn out
x 2
308
NAILS.
fine, without breaking in the hoof. A very tough
metal is also required for zo/zcelrorz'glzls’ nails, to allow
of their being forcibly driven against, the iron tire:
lmrclle nails must be of good fibrous iron, to allow‘
their points to be clenched, and their, broad heads to
stand the hammer. The various sorts of forged nails
are very numerous, probably over,‘ 300, with at least
10 different sizes for each sort, so that there are
upwards of _ 3,000 nails with different names, all of
which are perfectly mlderstiood by the persons who
manufacture them or use, them. The retail terms,
,fo‘wpcnny, sirpezmy, tcizpcimy, .&e., are not only indefi-
nite in themselves, but ,vary in different localities.
A much more precise method is to assign'to the sorts
certainv specific names which mostly express the uses
to which they are. applied‘; as lmrclle, pail, doc/r, scup-
per, mop, v850., while other sorts, of more general
application, are named after the. form of their heads
or points, as rose, clasp, (liamoml, &c. heads, and flat,
stamp, spear, the. points. The thickness is expressed
by the terms fine, tasters}, strong. The length of some
sorts is expressed in direct lineal measure, but it is
more usually included in the weight of 1,000 of the
nails referred to. Thus. the term 7 l6. rose means a
nail with a rose head and asharp point, the length
being about 1%,; inch, and 1,000 nails weighing about
7 lb. Rose nails are made from 1-2l to étOIbs. per
thousand. ‘ .
_ The following are some of the principal forms of
nails without reference to their size :1-—-
1. The kind called rose slzmya are extensively used
for coopering, fencing, and various coarse purposes in
which hard woodis used. . A thinner sort, called firze
rose, are used in pine and other soft woods, their
broad,‘ spreading heads being calculated to hold the
work down. 2. The rose, with flat or o/zz'sel points,
is used where the wood is in danger of being split by
thejdriving in of sharp points, which act as wedges 5
while, those with flat points, being driven with their
edges across the grain, prevent the splitting and hold
faster. 3. Clasp nails are commonly used by house-
carpenters in deal and similar woods: their heads,
mp ‘Tr






1 2 3._4 5 6 7 8 9 10
- ‘Fig. 1489. vnuin'rins or NAILS.
projecting'downwards, stick into the wood and clasp
it together, and'when driven below the surface, allow
a‘, plane to ‘pass ‘over them. 4. Clout nails are used
for nailing iron work and various substances to wood:
they havev a flat circular head, round shanks, and
sha'i'p points.‘ “The counter-slant (5) have countersinks '

if‘) W‘? are indebted for these specimens and their uses to an
excellent article on .NaiIsLiuHebert’s “ Engineers and Mechanic's
Cyclopzedia.”-
~ - -- I ~ - .» _ _

under' their heads, and chisel points, and are much
used by wheelwrights and smiths. 6. Fine day is
distinguished from a thicker nail, called strong or
wez'g/lzty dog. They are also used for nailing down stout
ironwork, and for various other purposes where the
heads (which are very solid, and slightly countersunk)
are not required to lie flush with the work; their
shanks are round drawn, and their points speared,
which adapts. them for piercing and clenching well.
7. The Kent-hurdle has a broad, thinnish rose-head,
a clean drawn fiat shank, anda good spear—point, well
adapted for nailing and clenching the oaken bars of
hurdles together. Gate nails are similar in form.
8. Rose-clench is a sort much used in ship and boat-
building. They are used in nailing on the wood
sheathing, which is soft, and liable to split unless
bored; and as the nails have no points, the ends
being left square, they punch out their own ‘holes,
driving a portion of the wood before them, hold very
fast, and render boring unnecessary. Hence they are
much used in making packing-cases and boxes. The
term GZWZGIL is derived from the mode of employing
them in boat-building, in which they are clenched
either by hammering down the extremity, or by placing
over it a little diamond-shaped plate of metal, called
a rose, and rivetting the end of the clench nail down
upon it, whereby the planks, &c. are firmly drawn
together. .9. Horse-nails, in common use. Formerly
the heads were made square, but the preference is
now given to the countersunk, chiefly on account of
their lying flush in the groove made for them, and more
securely attaching the shoe to the hoof. 10. Brads
form_ a large class.of very useful nails. Tao/cs are
also a very numerous and useful class of nails. The
chief place of manufacture for them and other very
small kinds is Bromsgrove in Worcestershire, where
it is a common feat of the work-people to forge a thou-
sand (1,200) ‘tacks so small as to fill the barrel of an
ordinary goose-quill, their weight being only about
90 grains. "
The apparatus required by the nailer is very simple:
it consists of a small hearth or forge for heating the
nail rods; an anvil, a hammer, and a few swage tools.
.lizilt'i ">,
ll". I r

Fig/(11490.’ will]; ‘re sex.
9 One of" the best‘ forms‘ of ‘nail forge is that by Mr _
Sperme, of Belper, and represented in Fig. 1490. It ‘
NAILS;
309."
is circular in form, so that 5 or 6 persons can work at
it at the same time. The brickwork from the base
is carried up in a cylindrical form to the height of 24:
inches, with proper openings for the ashes, water-
troughs, and the nozzle of the bellows. The circular
aperture in the centre is then covered with a fine cast-
iron grating, which forms the bottom of the furnace.
The courses of brickwork are next carried up a foot
higher, and the whole is surmounted by a cast-iron
plate, with a rim, or border, so as to form a conve-
nient dish for holding fuel to replenish the fire. In
the centre of, the cast-iron top plate is an opening
corresponding with the fireplace, to which is fitted an
iron ring, supporting on 3. iron pillars another ring
which carries the brickwork of the chimney. The
bellows are suspended from a frame, and are worked
by a lever or roc/c-sz‘afi which encircles the chimney,
so that one of the 5 or 6 persons who work at the
same fire is continually blowing it, and the fire being
thus kept at theproper heat for welding, good and
sound nails are produced. --
The anvil used in forging nails is a small cube of
steel, fixed to a heavy iron block surrounded with
stones, and imbedded in smithy slack, so that the
small anvil only is seen. The size of the hammer
depends on that of the nails to be forged, and
resembles the file-cutter’s hammer in shape, [see
FILE], the face being sloped or inclined considerably
towards the handle. The degree of obliquity, the
weight of the hammer head, and the size and shape
of the handle, are matters of individual experience,
one nailer seldom being able to work comfortably with
another man’s hammer; so that in moving from place
to place each man carrieslwith him his ‘own hammer.
The nailer begins his work by’ putting into the fire
the ends of 3 or a nail~rods, and works the bellows
until they are at the proper heat. He then takes one
of the rods, and resting it on the anvil, draws out the
nail by‘means of a few skilfulblows. The end, thus
forged, is now out off by means of a chisel, or fiac/r-
z'rorz, a short distance from the cutting edge of which
is a stop or‘ check for determining the length of the
nail. With nails of moderate size the rod may retain
sufficient heat to allow a second ‘nail to be forged and
cut off; but if the nails are of large ‘size the rod must.
be returned to the fire after one nail is cutoff. While
the rod is heating the nailer forms the heads of those
out olf by means of a dare, or piece of strong iron, 10
or 12 inches long, with a steel knob at each end per-
forated to the size of the shank or collar of the nail,
and countersunk so as to correspond with the head.
Taking up the nail, still red-hot, with a pair of plyers,
and putting it into the bore, point downwards, the
nailer strikes it upon the projecting end, which moulds
it to the shape of the perforation. By using different
bores the various’ forms of heads are produced. The
process is conducted with great quickness and dex-
terity. Instances are recorded of remarkable feats
by nailers, and we ‘have heard of one man making
170,000 double-flooring nails, 1,200 to 1,000 of 20 lbs.
weight for 2 successive weeks. _ ' '
Nails are formed by we”; as well as forging; they

are brittle, but'their cheapness recommends that for
such coarse purposes as the lathing of plasterers,
garden walls, stout shoes and boots, &c. Their brittle-
ness may be partially removed by annealing, and a
superior kind may be manufactured from malleable
cast iron. [See Aunnnmnm]
Nails are also extensively manufactured by cutting
or paras/ring. Mr. Holtzapifel states (Mechanical Ma-
nipulation, Vol. II.) that the first patent for making.
nails that he has met with was granted to John Clif-
ford, 17th July, 1790. The patentee ‘employed “two
rollers of iron faced with steel, in which were sunk
impressions of the nails, half in each roller. The in-
dentations were arranged circumferentially with the
heads and tails in contact, so as to extend the grooves
around the roller, and roll the whole rod of iron into
a string of nails, which required to be separated from
each other with shears, nippers, or other usual means.
Sometimes many grooves were cut around the rollers,
and a sheet of iron was then converted into several
strings of nails that required to be. separated nearly
as before.” The same inventor, also, took out a patent
soon after for making nails by punching. “ The plates-
of metal were forged or rolled taper, to the angle of
the nails, and were then cut up by a punch and bed,‘
each made- taper, and also to the angle of the nail.
Nails that required- heads were afterwards put into
a heading tool, or bed, having a taper hole of corre-
sponding form, that left a small piece of the thick end
projecting; and the head was upset with a punch or
die.” After this period some 30 or 40 patents were
taken out for making, brads- and nails; and in ma-
chinery of this kind the natives of the United States
of America are distinguished as inventors, in con-
sequence of thelarge ‘demand for nails in the construc-
tion of block-houses. So long since as the year 1810,
the Americans had a machine which performed the
cutting and heading: at one operation, and produced
above 100 nails per minute. - i , _ -
The principle upon which nails are cut may be
illustrated by a narrow strip of paper, by cutting from
the end with a pair of scissors, triangular sections in
the form of fine wedges, and turning the paper over
after every cut, so that the head, or broader part of
every'clipping, may be taken from thepoint of the
preceding one, and cice-verscZ In this, way we get
the form of that kind of shoe-nail called a spar-rattle,
or sparrow-bilflfrom its resemblance to the mandible -
of the bird. ‘In Fig. 14:91, the larger wedges, A, re-
present sparrables, and the smaller ones :8, sprigs,
WV lit ll ljl


which are also used by shoemakers and other work-
men. If, instead of this slip of paper, we have a slip
or rand of iron, and instead of scissors the fly-press,
with its cutting punches, [see Burrow}, it is easy to
see how nails of the simple form described are manu-
factured. By using the punch the nails are not bent
310
NAILS.
or curled, which they are liable to be if out with
._.-.__:_:_. shears. In Fig. 1492, m is a rect-
, ‘ angular mortise in the bed of a fly-
_ press, used for‘ cutting brads, such
‘ as are shown at c, Fig. 1491; the
punch, 12, is made to fill the bed, but a
portion of the punch represented
by the black part of the figure, is
nicked in, or filed back to the ‘size
and angle of the brad. A pin or stop
s, guides the strip of metal i into the mortise, and in
order to prevent it from passing to‘o far’ over the hole
in the-bed, the punch is never raised quite out of its
bed: the‘ metal is thus stopped by the tail of the
punch, and its outer or rectangular edge removes the
brad. The strip is turned over after every descent
of the punch, so that the head of one brad is cut from
the point of the one previously made, and this turn-
ing over is quickly and accurately .done with the
assistance of the stop and the taii acting as guides.
The upper surface of the bed is a little inclined, in
order that the cutting may begin at the point of the
brad. In cutting brads with heads and headed .nails,
as at 1), E, Fig. 1491, the whole of the strip of metal
can be used without waste by the arrangement shown
' " in Fig. 1493, simply by turn-








. .. ___..,-_. .__—_..__._ni.___. ———-
// '4




f ing over the strip after each
z ,9 cut at 272 represents, as be-




fore, the rectangular opening
in the bed of the press, 79 the
tail of the punch fitting into
it: s is a stop placed .at a
‘ distance from the opening in
Fiy-1'493- the bed corresponding to the
vertical height of the head, so that the strip of iron
overhangs the. aperture by that quantity; it will also
be ‘seen that the width of the {point of the brad is
equal ‘to the projection of the ‘head. Now when the
strip of iron is first applied, a wedged-shaped piece is
cut off, equal to the difference between *the tail of the
punch and the bed, and there is a small projection
left in the strip near .‘sz On turning over the strip,
this projection rests against the tail of ‘the punch, as
shown at s, so that the next cut removes a perfectly
formed brad, and leaves the head of another ready‘
formedon the strip.
The iron from which nails are to be .cut or punched
is rolled to the proper thickness, and the plates are.
I//‘li'
/ it at
~15! - .w'l rill-e
/' spill n‘ p:


if. i I 'e z . l‘.
l l . a l , l
i i 1'n ,- i . i- with?
' f-I 'toénnll __ Q
. I p.
1 . ____ =lllllllllll~ ll 5??‘— M-i; .
z e z I’
2, V ,i', we.
. I
cut-"up into ‘st-rips of ‘the width required for the'len‘gth
of ‘the nails by ‘means of a powerful cutting-‘press.
When brads or nails are cut out by steam power,

which is the usual course, a fly-press is not used, but
the moving cutter is attached to the end of a long
arm, (as in the lever-press, Fig. 1494,) to which a
rapid up-and-down motion is given by a crank or an
eccentric, as at e. The strip of metal is held in a
spring clamp e, at one end of an iron rod, the other
end of which is supported by a forked rest r; and by
this simple contrivance the boy who attends the ma
chine can turn the metal over with great rapidity
while the moving cutter is ascending. In order to
prevent the necessity for turning over after every
out, a toggle or knee-joint is substituted for the screw
of the fly-press. In this joint “the two parts a b and
I) c, Fig. 1495, are jointed together at 6 ; the end a


.Fig. 1495..

is jointed to the :upper part of the press, and e to the
.top of the follower. 'When the parts a b and b e are
inclined at :a small angle, the extremities a and c
are brought closer together, and raise the follower;
but when the two levers are straightened, a and a
separate with .a minute degree of motion, but almost
irresistible power, especially towards the completion
of the stroke. The bending and straightening of the
toggle-joint is effected by the revolution of a small
crank united to the point 15 by a connecting rod bf.”
(Halter/pied) The whole press is moved upon the
pivots e e by the rod g, so that it is alternately inclined
to the right and left to the angle of such nails as are
wedge-shaped or have no heads. Some machines
are so {contrived ‘that as soon as the nail is cut off, it
is grasped between forceps or dies, and a hammer,
also set motion by the machine, strikes a blow which
upsets or spreads out the metal, forming the flat head
in cut nails and tacks.
After the nails are out ‘or punched, they are an-
.‘ nealed by being put ‘into close iron boxes, heated in
.. Ovens; and. then left to _ cool slowly. They are then
; packed in strong‘ hempen hag‘s,,or made up in bundles
or casks, according to the market for which they are
destined.~ Of the-vast quantities of nails manufactured
5 in Great Britain, by far the larger proportions are
5 consumed at home : there is, however, a considerable
trade-to the colonies and the East. rill-1e continent of
f Europe is chiefly supplied with nails from Holland
‘and Belgium. The Jury Report of the GreatExhi-
hition states that “the price of nail-rods is lower in
Belgiumythan in England; a fact which seems to
indicate that'a constant and regular demand for one
NAPHTHAI—NAPHTHALINE —NAVIGATION INLAND.
311
description of iron will not only insure its supply,
but diminish its cost, possibly by the inducement held
out to the exercise of ingenuity on the means of econo-
mising the cost of production.” Some of the hand-
made nails of Belgium are referred to in the highest
terms ‘of’ commendation; ‘and those of Austria are
mentioned as‘ being remarkable for a peculiar twist
given to the shank of the nail, which greatly increases
the hold. This twist is not unusual in railway spikes.
It is said- that the United States of America manu-
facture from 35,000 to 410,000 tons of nails every
year. “For this and other purposes, such as ship-
building, boiler-making, 850., large quantities of cheap
iron are imported from Great Britain, which, owing
to the wide extent of American sea-board, can be
supplied to most of the southern states of the Union
at a cheaper rate than would be the case even were
the prices in Pennsylvania and Great Britain the same
at the works.”
NANKEEN. See Corron, Vol. I. p. 4:46.
NAPHTHA. In our article ASPHALTUM a number
of natural inflammable substances are enumerated,
among which is naphtha, r007: ‘oil, or petroleum. The
term naphtha is usually limited to the thinner and
purer varieties of rock oil; and petroleum to the
darker and more viscid liquids. They are mixtures
of various hydrocarbons; but in its purest form
naphtha may be said to consist of Cell», and yielding .
Such a hydrocarbon ‘
is obtained as a natural product at Baku on the shores .
a vapour of the density of 2'8.
of the Caspian, where the soil is a clayey marl im-
pregnated‘with naphtha. It is also procured from
Monte Ciaro, near Piacenza in Italy, by sinking pits
in the horizontal beds of argillite, which gradually fill
with water; and the naphtha oozes out of the rock
and floats upon the surface, from‘which it is skimmed
off. Naphtha may also be obtained by the distillation
of petroleum, and it is one of the results of the de-
structive distillation of coal [see Gas-LIGHTING]: it
often passes with the gas to the distant parts of the
apparatus, and may be found in gas-meters and gas-
met'er tanks, and even in the mains.
Carefully rectified naphtha, whether from natural
or artificial sources, appears to possess similar proper-
ties. The sp. gr. of the purest Persian and Italian
naphtha is said to vary from 0'7 50 to 0760, while
that of coal-naphtha may be ‘820 or higher. The
odour of the natural naphtha is bituminous but not
unpleasant ; that of coal is penetrating and disagree-
able. It does not congeal at zero. It ignites readily,
and burns with a voluminous sooty flame. It is not
soluble in water, although it communicates its odour
to that fluid. It dissolves in absolute alcohol, in ether
and the oils. The boiling-point varies in different
specimens from 320° to 365°. It dissolves caoutchouc,
and hence its value in the manufacture of water-proof
clothing. [See Caourcuouc]
NAPHTHALINE, C10H4, 'a white, solid, crystal-
line matter obtained by’ distillation from coal-tar. It
fuses at 176° into a clear colourless liquid, which
crystallizes on cooling. It boils at 4¢13°, and gives
off a vapour of the density of 4'528. Its sp. gr. is

about 105 : it is unctuous" to the touch; its taste'is
slightly aromatic. It exhales a faint peculiar odour,
which has been compared to that of the flower of the
narcissus: it slowly evaporates if left exposed. When
ignited it throws off a large quantity of smoke, or
rather of black snow. It is slightly soluble in hot
water, but abundantly so in alcohol, ether, the oils,
and naphtha. It is deposited from its hot alcoholic
solution in iridescent crystals.
NAPIER’S BONES. See CALCULATING MA-
CHINES, Fig. 397. ‘
NAPLES YELLOW. This fine colour, used in
oil-painting and for porcelain and enamel, is prepared
in Italy by a secret process. Dr. Ure ‘gives the
following recipe: 12 parts of metallic antimony are
to be calcined in a reverberatory furnace with 8 parts
of red lead and 41 parts of oxide of zinc: the mixed
oxides are to be fused, and the mass then triturated
and elutriated into a fine powder. Many of the pur—
poses for which Naples yellow‘ was formerly applied,
are now supplied by chromate of lead.
NATBON. See SODA.
NAVAL ARCHITECTURE. See SHIP.
NAVIGATION INLAND. The prosperity of a
country depends greatly upon the facility with which
its different parts and members can communicate with
each other; and it is instructive to observe how
rapidly England developed her commerce and industry
as soon as she began to construct extensive means
for locomotion. Next to good roads, the introduction
of a system of inland navigation must be regarded as
one of the most notable epochs in- the history of
British commerce ; and although railroadshave in some
measure superseded canals, yet at their first introduc—
tion they were comparatively as important as railroads
now are. The most remarkable thing is, that while
many other nations had long enjoyed the advantage
of canals, England did not even begin’ to adopt the
system until the year 17 5 8, when the Duke of Bridge-
water set the example. At this. time on our best
roads the force of traction‘ was not less than %th
or T‘gth of the load or carriage ;. and when this was
heavy the speed could not exceed 2' miles or- 2% miles
per hour; whereas on a canal the foreeof'traeticn at
that pace is not above 10100 th, or at the most 950th,
of the load. This advantage was. soon appreciated,
and a few years after the genius of Brindley and the
perseverance of the Duke of Bridgewater had- been
crowned with success, Great Britain was penetrated
with canals in every direction, so as to connect her
various points of product and consumption. Before
the general introduction of railroads, the aggregate
length of navigable canals in England alone exceeded
2,200 miles ; and in addition to canals, such rivers as
were capable of it were rendered navigable; so-that
there was no place in England south of Durham that
was distant 15 miles from water communication,
while the principal towns and seats of manufacture
were in direct communication therewith. It is even
stated that the general introduction of railroads.
which it was supposed would entirely supersede canals
has not only not done so, but has in some cases actu—

312
NAVIGATION INLAND.
attained by "three methods.
ally improved'their traffic; for while a railway to a
populous place increases its means of commerce and
industry, and consequently requires a larger amount
of carriage, the lower toll charged on the canal than
the railway will cause the former to be preferred for
‘certain heavy goods. - ' - > ' i ' ~
It has not been. ascertained in what country arti-
ficial water- communications were first constructed;
but it is probable, that ‘canals which had originally
been made as 'aqueducts for drainage,v or for irrigation,
were afterwards applied to the purposes of navigae
tion. Works of this were constructedin Egypt
at a ‘very early period,‘ and they are know to have
existed in China. before the Christian era. . The first
canal constructed in-Europe is‘ supposed to be that
cut‘ byiXerxe‘s' across the low isthmus of Athos. The
Romans ‘formed 'canals in Italy, and in the Low
Countries about'the outlets of the Rhine. In modern
Europe, the art of cutting canals was first practised
in Northern Italy and Holland. Those formed in
Lombardy, between the. eleventh and thirteenth
centuries, were chiefly intended for ‘irrigation. [See
DRAINAGE] The canal from Milan to the Tcsino
was rendered navigable in 1271. In the 12th een~
tur , when Flanders was the commercial centre of
Europe, canals were constructed. In Holland, canals
are like the roads of any other country, and are used
as such. ‘ - ~
The chief principle to be worked out in the con-
struction of a canal,.is the formation of a perfect
level or series: of levels. ‘ In a flat country like
Holland, the work is easy, but where the face of the
land is diversifiedl'by hill and-dalathe object may be
1st. 'By elevating the
depressed portions. by: means ,of' embankments .and
aqueducts ; depressing “the elevated portions
by vmeans :of- ‘cuttings and tunnels; and 3dly. By
forminga ‘series of stairs or steps termed loo/cs, by
which one level portion is made-to communicate with
another-either higher or.‘ lower than itself, the water
being maintained at the higher. level' by means of
gates, so placed that the pressure'of the water against
them keeps them closed.1 The proportions in which
these three methods are combined, are determined by
a careful survey of the intended line of canal; and
the general level, at which it is fixed must have refer-
ence to the means of obtaining suflicient feed of water

(1) The various claims to the merit of having invented the canal
lock have led‘ to" the disturbance of much learned dust. It was
probably first used in“ Italy, and was an improvement. on the
ancient sluice. Belidor, in his “Architecture Hydraulique,”
atfribultesflthe invention. to the Dutch. Italian writers state that
the celebrated Leonardo da Vinci first used locks, in the Milanese
canals," in‘1497; but these writers are by no means agreed on this
a V subjecty A recentwriter is disposed to attribute to England an
early,perhaps an independent, application of the pound lock, on
the.‘ ground that the English term lock is purely national. It is
not,’ he remarks, the Italian-.sostegno or come, the Dutch sZu-ys,
thefFre'nch e'cl'zzse, but'the.Anglofsaxon'loc, or enclosure; and he
infers 'thatvif wefhad borrowed the _i_pvention, we should also have
borrowed-thcfname. "In reply ‘to thi'siargunient, ‘it has been said
that our term is at‘ least an exact translation of the Dutch stays
and 'thegGeifinan schleussc, which,.whether to be traced through
the French-éclzzls'eand Italian chime to'the Latin claudo and clude,
orv to ‘the nearer source of the Teutonic schlz‘essen, has the same
signification, to enclose,‘ or shut up.

from the adjacent country, and also‘ to its junction
with other canals.
It is, of course, desirable, as far as possible, so to
proportion the excavations and embankm ents, that'the
quantity of earth from one shall suffice to form the
other. A canal running along the side of a declivity,
may .require one bank to be raised more than the
other, or one may require to be excavated, while the
other is embanked. When embankments and exca-
vations frequently alternate, the mass of earth
required for raising ‘one part is made to correspond
as'far as ,possiblewith that removed from the other.
In order to ‘avoid ‘cuttings vin solid rock, it may in
some cases bedesirable' to carry the line of the canal
out of the direct route.‘ These ‘and many other points,
the engineer will have to determine in laying out
the line. -~ ' ~ . -
The form of channel for the canalis of importance.
Except in tunnels the sides are seldom vertical. The
bottom is generally made to slope off upwards, the
amount of slope being regulated by the nature of the
soil. The slope may be liable to wear from the motion
of .the water in such a way as to make the towing-
path irregular in width. This is remedied to a certain
extent by planting the sides with aquatic shrubs,
and also by driving stakes into the banks at short
intervals along the water line, so as to form a kind of
- rough wicker—work. Where embankments are formed
of loose materials, or excavations are made in earth,
sand, or rock, so porous as to allow the water to filter
through, it is usual to make the excavation wider and
deeper than the intended dimensions, and to line it
to the thickness of 1% to 3 feet with jmolcllecl clay,
that is, good clay well beaten up or tempered with
water, and then mixed with a certain, proportion of
gravel, sand,‘ or chalk. ‘If clay were used alone, and
the water in the canal sunk below the ordinary level,
the exposed part of, the clay would, crack, and when
the water rose again, it would escape by the cracks,
and enlarge them, and at length wash away all the clay.
The puddle-‘stuff is usually applied in 2 or 3 strata;
the first stratlnn, about 10 or 12 inches thick, is first
allowed to set, when another course of about 9 inches
is applied, and so on until the required thickness is
attained, care being taken to, work the puddling-stuff
each time, vas as to unitehit with the stratumjjust
below. On the top courseof puddle, a layer‘ 112- to
9 feet thick of common ‘soil islaid. A trench 3 or 41
feet in width is also formed in the middle of ‘each
side bank to at least 3 feet below the bottom of the
canal, and this puddle-ditch or ‘patter as it is called,
is filled ‘up with, puddlingastufi’, its object being chiefly
for the, purpose of ‘preventing rats and vermin from
perforating the banks; for when once a small opening
has been made £01’ thewater, it is quickly widened
by, the flow, SO that in..a_ few hours, damage may be
done which may’reqllil'e weeks or months to repair,
and‘ the canal; may even be emptied of its water.
Eig._14.96 represents a. section of a canal with a
puddle lining P10, .1 foot 6 inches thick at the bottom,
and 3 feet in the ‘Slope. ,T is the towing-path,
.10 feet wide, and n‘s the natural surface. Piglet)?
NAVIGATION INLAND.
313-
shows a section'where the soil is ~retentive; T is the
towing-path, and r the puddle ditch.
In carrying a canal over a valley, an embankment
may be formed, or, an aqueduct constructed of timber,
stone, *brick, &c. In a deep and extensive valley, an
aqueduct would be preferred. Where the Shrews-
\
\


bury- canal passes over the valley of' the Tern for. a
distance 0f'180 feet, Telford constructed an aqueduct
of cast-iron, the nuts and screws only being of
wrought—iron. A canal aqueduct of unusual dimen-
sions was constructed by Mr. Jessop, on the Ellesmere
canal, for crossing the Dec, about 20 miles ‘from











. ._ ._ T l
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a \ ‘ \ \“~.~ ' .1 .,-‘:' v1 ”- ‘5- r“ I a ‘N\S\\\‘§ §-\\ . ‘ Mrs: ------------- -. ......... _____________ __ cg. {i
~\..~\\\ . .- \ \\ \:~..
"<‘\\-\_ _\ \ \ \v\.\\ \v
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Fig.1é96. 'rnnnsvnnsn snc'rrou or CANAL wi'rn PUDDLE LINING.
(Birmingham and Liverpool Junction Canal. Telford.) 'i
. q T I




______—___.______
.............. i
"N \.
‘fifF-ufilu ‘ “\ a
s


Q
_\
~




\ \ .
Fig. 1497. Tnnnsvensn snc'rlos in A nn'rnn'rrvn soIL.
(Birmingham and Liverpool Junction Canal.
Chester. 19 massive conical pillars of stone, 52 feet
apart, the middle one being 126 feet in height,
support a number of elliptical cast-iron ribs, which,
by means of vertical and horizontal bars, support a
cast-iron trough or aqueduct about 1,000 feet in
length, 20 in width, and 6 in depth, composed of
" massive sheets of
- cast-iron cemented
M91498’ and riveted toge-
i ther, having on its
south side an iron
platform and rail-
ing for the towing-
path, which over-
hangs the water,
and is supported
at intervals on tim-
ber pillars, as re-
presented in Fig.
1498. Of embank-
ments, one of the
largest is between

lluummnuim:uuilinium unflT l Olverton and
31.3,?! ‘,ai'f “7*” ‘1:’:
r‘ "M- ltlw Cosgrove, on the
' z‘, .
l‘ .1 Grand Junction
Canal; it is half a
. mile in length, and
in some parts 30 feet high, the object being to
avoid the construction of .a number of locks. In'the
valley of the Boyne, in Ireland, is an embankment
90 feet high. ' ' ‘ ‘
‘ When the ground is higher than the level of the
intended canal, the ‘reverse process of- excavation is
adopted, unless the depth is so great that a tunnel is
preferable. In some cases, the value of the ground
above may cause a tunnel to be preferred to an exca-
vation. The first tunnel driven for the purpose of
canal navigation, was on the Languedoc canal, in
France, and the first in this country, was the entrance
_ sunk either _ for the

Telford.)
made by Brindley to the Duke of Bridgewater’s
canal at Worsley. In the construction of a tunnel,
the level and bearings of the line require much care.

Fig.1499. cnoss SECTION 01-‘ 'Iranncasrnn‘runnnr.
(on the Trentyand Mersey Canal, l'elfo'rd). -
The ground is first surveyed by tracing a line in a
vertical plane ~parallel to the direction ofjth'e tunnel;
to obtain which the relative levels of the principal
points along the line *
upon the surface are
ascertained. At cer-
tain’ places along
this line, vertical
pits or ‘shafts are
purpose of ventila-
tion, 'or' for com-
mencing and carry—
ing on the work of
driving the? tunnel '
at several places .si- '
multaneously. The
earth, or rock, is
hoisted out ‘through the shafts, and ‘water is pumped
out. . The shafts having been sunk to the required

Fig. 1500. ELEVATION or crznrnnrnc.
314:
'NAVIGATION INLAND.
depths, as ascertained from the levels taken at the
surface, a heading or small tunnel sufficiently high
and wide to allow the men to move freely while
at work, is commenced just below the crown of the
intended tunnel. It is ~ carried forward from one
working shaft to another as" nearly as possible in a
straight line, until a connexion is formed between all
the shafts and the two ends of the tunnel. If in the
progress ‘of- the headingnithe air- become too impure
for-the men to‘ respire, an air-shaft is commenced
from~r above,._.andj sunk: to the point" where the men
ceased to drive. In‘drivinglthe tunneloff the Thames;
and Medway canal, 11 air4sihaft’s' were required in

addition to 12 working shafts. When the heading


between two working shafts is completelyr excavated,
the roof of the tunnel is begun, and this may require
to be completely lined with brick or stone, or it may
be suflicient merely to smooth the surface.
One of the distinguishing features of a canal is the
means by which an ascent is made to a higher level,
or a descent to a lower. This is done by means of
Zoo/rs. The level portions between locks are termed
pounds, and 1 the frequency with which looks and
pounds- alternate will "depend on the undulations
.of the ground. the ground. ascend uninter-
ruptedly', or ascend and descend at short intervals,
the pounds must be short and the locks frequent; if
the ground be tolerably level, but few locks will be
or‘ r '



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‘ Figs'.-155i91;,‘1502. sscrrronnr. ELEVATION AND PLAN or A CANAL LCCK.
' required. There is one English canal in which a lock
occurs on ‘the-‘average at: every half-mile; while in
another case, there is only: one look in 19 miles.
A single lock usually consists of an oblong chamber
about 70‘ or 80 feet long, 0 c’, Fig. 1501, and 7 or 8
feet wide, or only just sufiicient to allow the boats to
pass through it. Its sides and invert, or floor, are
lined with brick or stone. By means of this chamber
an upper pound is connected with. a pound next
below it, or . a
71-‘ lower pound with




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y- tirmiminniinm ‘@mpmmunmmm one. In Fio._
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x \, _ floor of the up-
§§\_l_ \ per pound, and
;.',..,.,,,. ,-,,-, W
i X i Fig.
L 1? of the lower
pound, which is
p v on the same level
the. floor of the lock-chamber. P G are the gates
y'vhi'ch retain the water at the upper level. -. They


\ __\ _ -. \\§§
1503. UPPER. LOCK. earns.
' areglslightly curved; as shown ate, Fig. 1502, and
when in motion, they turn upon their. ends :0 c’ as
vcentre's: they are‘ of sufficient ' breadth‘ to meet-and
form an ~~ angle ate, a position in which‘ the gates
j ‘mutually support, each other, and the pressurev of the
water against them tends to keep them more closely
shut. They are opened by means of oapstans K K’,
the chains being attached to the gates .under the
water, and passing through ‘tunnels “in the sides of
the lock. They are closed two,‘ other capstans
K” K'”, the gate-c e being shut- by K'”, and the gate
e 0’ by K”. A similar pair of vgates is placed at the
lower end of. the lock 0 3L:~ they. are on-the same
level as the upper gates, and hence. have a greater


__ v by
___s. y " i M
"— i Ill
n‘ ~‘ 11 " '
i‘‘~:\\\\\ 1' ‘f o‘ I “E
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firé’tn- :~
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Fig. 1504. LOWER LOCK earns.
length than those, as much as the upper pound is
above the-lower. This be seen in Figs1503,
1504.‘. '
Now, suppose a laden barge has: to pass from a
lower to an upper level, an operation which ‘is called
locking up, it is thus performed:—- On arriving at the
lowergates L e’ ‘these are thrown’op‘en', the boat

admitted ‘into the lock-chamber, and the gates ‘are


NAVIGATION INLAND.
1315
closed behind it. Water from the upper pound is
then let into the lock-chamber by opening the channels
s s’, Fig. 1502, in the sides of the upper part of the
lock, which can _be opened or shut by means of
sluices, and water then pours in from the higher
A

limertwmllr.

1
..__.-_...
‘r _I":._ run: ..:_



Fz'g. 1505. FRONT ELEVATION or IRON LOCK GATE.
(Caledonian Canal.) '
pound, until the water in the lock-chamber is at the
same height as in the higher pound. As the water
in themchamber rises, the boat rises with it, and when
the flow has ceased, the upper gates e are thrown
open, the boat is towed out of the lock, and proceeds


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1.. -|b~;'“-“."-

Fig. 1506. BACK ELEVATION.
Fig. 1508.
scnnw roa


ormrme
Fig. 1507. szcrros snowme run cunvz asp supra-me
or THE Gare. SLUICES.
on its journey along the upper level. In passing
from a higher to a lower level, or Zoe/ring dozen, water
is admitted into the lock from the higher level; the
gates are then opened to admit the boat, and are im-
mediately closed. The sluice is next opened in the


opposite gates, not as in the former case, for'the
purpose of raising the water in the look, but for
letting it out until its surface coincides with that of
the lower level. This being done, the gates are
opened, and the boat towed out as before. Thus it
will be seen that a lock is a kind of liquid ‘stair by
which the boat may ascend or descend, not by ceasing
to float for a single instant, but by varying the level
of the water in the enclosed space, or look. In‘this
arrangement a certain quantity of water is lost from
the higher level, depending on the direction in which
the boat moves, and whether the lock be full or
empty at the time. The following will represent all
the cases that may occur :—
Finds the lock’ Lets out of the Leaves
upper pound, the lock,
Boat descending m( Full ....... .. No water ....... .. Lmpty.
lEmpty ..... .. 1 lockfull ..... .. Empty.
- Full ....... .. llockfull Full.
Boat ascendin g Empty .... .. llockfull Full.
Hence, when a series of boats follow each other
in the same direction, up or down, 1 lockfull of water
will be expended for every boat that passes; but if
the boats pass alternately up and down, only 1 1001 -
full will be required between each pair, since every
ascending boat requires a lockfull and leaves the lock
full, and every descending boat, finding the lock full,
does not draw upon the upper pound for water.
When the slope is considerable within a short
distance, a chain of looks, or succession of chambers,
Fig. 1509, is constructed, the lower gates of one
chamber forming the upper gates ‘of the next below
it. By this-contrivance, only one more than half the







''''' a / lZi . Z was
s\\\\\\
Fig. 1509.
number of gates for the whole of the series, sup-
posing them to be detached, is required, and much of
the machinery for opening and shutting them is
saved. This arrangement, however, causes a. large
expenditure of water in certain cases, as, for ex-
ample :—
Finds the locks’ Lets out of the Leaves all
upper chamber, . the locks,
Boat de—} ... “{FuH .......... .. None Empty.
scending Empty ....... .. 1 lockfull ........ .. Empty.
Full .......... .. 1 loekfull - Full.
Boat as-}_ { asmanylocksfull
cending Empty ....... .. {as there arecontt} Full.
guous chambers.
In these cases the term empty does not mean that the
chambers contain no water, but that the water is in
each at its lower level ll‘, Z 12, &c., the dotted lines
showing the levels in the full locks. Hence it will
be seen, that when a number of boats follow each
other in the same direction, up or down, each boat
will require one lockfull of water; but if a number of
boats pass alternately up and down, each pair will
require between them as many locksfull as there are
contiguous lock-chambers, which in the present case
3:16;
NAVIGATION INLANDJ
is three; ‘for the previous boat having left all the
chambers empty, the ascending boat will require 3
locksfull, but as it leaves all the chambers full, the
next descending boat not draw off any water
from the upper chamber. ‘ ~
‘ It may readily‘be imagined, that the summit level
of a canal, from, which all ‘the lower pounds obtain
their supply, may gradually become exhausted, espe-
cially in summer, or in dry seasons, when evaporation
is rapid or water scarce. ‘By a contrivance called a
dou‘éZeZoc/s, one half of the, water which would other.-
wise escape to. thelower level is saved. A double
lock consists of twooblong chambers placed side by
side, but separated by a massive brick partition in
whichis a sluice connecting the two chambers; each
chamber has. a gate at each end, the upper connected
with the upper pound of the canal, and the lower
gates‘ with the lower pound. If we suppose one of
these chambers to be filled to the level of the upper
pound, and the other chamber to that of the lower
pound, and that a boat is about to ascend, the ar-
rangement would be as follows :—The boat would be
towed into the chamber in which the level of the
water was lower, and the gate would be closed behind
it; all 4! gates being now closed, the sluice in the
partition wall would be opened, water from the full
chamber would flow into that containing the barge
until there wasv an equality of level in ‘both ; the
sluice would next be closed, and a valve opened for
admitting water from thehigher pound, by which
the barge would be raised to the higher level, and the
upper gate of the chamber in which the barge is,
being opened, the barge would be towed out. In the
reverse ‘operation, or locking-down, a barge would be
towed into the upper level chamber, the gates shut,
the sluice.’ opened, and the water in the two chambers
brought to the" ‘same level; the sluice would then
be closed, and a valve opened between the lower
pound and the chamber in which the barge is floating,
the water sinks to the lower level, the lower gate is
opened, and the barge is towed forwards on her
journey. It will thus be seen, that by means of a
double lock a good "deal of water is saved._ If the
lock contain more than two chambers, the economy
may be still ‘further carried out, but the increased
cost would not compensate for the advantage; The
average ‘lift of a lock, or the difference of level
between the upper and lower pounds, is about 8 feet,
but -itv may vary from a few feet to 18. ‘If in a canal
of a certain‘ length a certain amount of rise is to be
effected, it may be produced by a small'number of
deep locks, or a larger number of shallow ones. In
the former‘ case less time is expended, and in the
latter, less water. '
The ‘supply [of water .to 'a canal is an important
consideration; Where the two extremities of a canal,
suchpas the‘, Great Ship Canal 1' of Holland, communi-
‘cate; with 'gtlielsea, the supply of water is from the sea.
Thighowever; isnfot a very usual'case. - Most of the‘
canals, ‘in England are 'fed by; natural springs, which
must be ‘so regulated as to‘ discharge their waters into
the-canal. top-supply the waste of lockage. ' When

a ‘navigable communication has 'to be established
between separate valleys, or basins, and a double
lockage, or descent, in both directions, from an inter-
mediate summit level, cannot be dispensed with, the
summit may be too much elevated above the adjacent-‘
streams on either side to obtain a supply of water
from them; or such streams may be engaged in
turning mills, &c., and their waters cannot be spared
for the canal. In such a case a supply of water is
obtained by collecting‘the flood waters of the higher
grounds into‘ reservoirs, from which they may be
drawn off as occasion requires for the service of the
canal. In the construction of such reservoirs much will
depend on localci-rcumstances, but the ‘engineer takes
'care to fix a reservoir at a levelv sufficiently low to
collect the flood waters from a tolerably wide extent
of country, while at the same time the reservoir is
situated so as to discharge all its water into the
summit of the canal. If the bottom and sides of
the reservoir are, from the nature of the rock, im-
pervious to water, the expense of rendering them so
artificially will be saved. Where the reservoir is
situated some distance from the canal, the water may
be discharged from it into the canal by a brook-
course, or ancient channel; but it is ‘more usual to
construct a feeder, or artificial brick channel, for the
purpose;- and in many cases, cast-iron pipes have-been,
found most economical, as in crossing valleys or other
streams. A clause is usually inserted in Canal Acts
of Parliament, authorizing the company to search for,
and divert to their use, all springs of water within cer-_
tain limits on either side of their line as feeders for
the canal. In the Acts for the Newcastle-under-Lyne
Junction, the limit is fixed at‘ 1,000 yards; in the
Aberdeen, Polbrook, Thames and Medway, Wilts and
Berks, and a few others, ‘the vlimit is 2,000 yards. In
very dry weather all the water sources of the com—
pany may be so exhausted ‘that. they cannot obtain a
supply adequate to the waste by lockage and evapora-
tion, and it then becomes necessary to purchase water
from the neighbouring water companies. The cost of _
this is sometimes very high.
The lockage water is sometimes economized by
means of side-ponds, which serve a purpose similar to‘
that of double locks. Two ponds are used for each lock,
each pond having the same horizontal area as the
lock, and made to receive one-fourth of its fill of
water. One of these ponds, that to the left of n B o,
&c., Fig. 1510, has‘ its bottom at half the height or
lift of the lock (which is represented by'the vertical
height between the top and bottom horizontal dotted
lines), so'that' when avalve ais opened into it from
the full lock A, this pond receives one-fourth of its
contents vas shown at 13: this valve is now shut, and,
another 8’ opened between the lock and the second"-
pond, the bottom-of which is at one-fourth the lift of
the lock, and this pond in its turn receives another
fourth7 of .the water as shown at c: the second valve-
jis next shut, and. the remaining half-lockfull of
“water; is .allowed't’o ‘flow. into the lower pound ‘in the .-
usual manner, leaving the lock and ponds'as shown -‘
;at '71). .T Whenthezlock is to be filled a'gain‘,~th'e lower.
NAVIGATION INLAND.
317.


‘pond is first opened and the water allowed to flow.
into the look, as at n, and then the higher one is
opened, by. which half the rise is effected, as at F.
Mr. Field. has proposed to construct side ponds to
act on the principle of an inverted siphon, the water
rising to the same height in one limb as in the other.
The lock is to be connected with a side pond by


F
k ‘2’; =1; we’ re-
- ‘Q . _ - q; "-- K-xs .m- I.‘
1. C e“ we . 3s \"h
“ \Q l \ §
. km . Q \.
l /// I


Fig. 1510.
means of a long pipe or culvert, so that when the
water in the lock is allowed to flow suddenly into the
empty pond, it may rise in this nearly to the level to
which it falls in the lock, and as soonas this occurs
the valve or sluice‘ in the culvert is shut. A similar
effect takes place when the water is to be restored to
the empty lock, only whatever may have been the loss
of water in the former case, the total loss is now
doubled. .
The boats or barges used on canals are specially
constructed for the kind of traffic in which they are
engaged. They are much longer and narrower than
those used for river navigation, and are tracked with
more ease and speed than when of a wider and shorter
figure: they also‘ do less damage to the sides of the
canal. In the central districts of England the boats
are usually sharp at both ends, and have no project-
ing stern ; they are guarded by three rows of wrought-
iron bands, which extend round the bows to the dis-
tance of 20 feet on each side above and below the
water line; the bottom is ‘nearly flat, and there is a
keel which appears to be a useless appendage. Coarse
and heavy goods are conveyed in open barges; but
goods which require to be packed with care, and de-
fended from the weather, are usuallyr carried in fly—
boaz‘s. These are long and very narrow barges with
flat bottoms, in which the goods are stowed nearly
from end to end, and to a considerable height above
the edge of the boat, and the whole is protected by a
canvass covering. There is a small cabin at the stern
end for the boatman, who frequently has his family
with him. The boats and barges are tracked or
towed by one or two horses,1 which move at the rate
.of from 3 to 42 miles an hour upon the gravelled tow-
ing path at the side, the horse being connected with
the boat by means of a long rope. Some of the early
tunnels were made so small as not to leave room for

(1) In Holland the irekschuz'ten, or drag-boats, are sometimes
tracked by men: the same practice is common in China, and was
the case on the Thames and the Severn till near the end of the
last century.

a towing path, ‘in which case the horse isunloosed
from the boat, and conducted by the road above to
the other end of the tunnel. The boat is got through
by two men, who place two boards in a horizontal
position near the head of the , boat,and lying down
on their backs push against the walls of the tmniel
with their feet in a slanting direction. In this way
they urge the boat slowly forward until- it emerges
from the tunnel, when the horse is hooked on as be-
fore. In some cases a steam-tug is used for drawing
the barges and boats through the tunnels. _
About 20 years ago a remarkable increase in speed
was made on the Glasgow and Paisley canal, in boats,
for the conveyance of passengers. These boats were
run at the rate of 9 or 10 milesan hour‘; , they are '7 0‘
feet in length and about 5% broad: they carry70 or
80 passengers, and occasionally over 100. _ The hulls
of the boats are formed of light iron plate and ribs,
and the covering‘ is. of wood and light oil-cloth, so
arranged that all the passengers may be under cover.
Each boat is drawn by 2 horses, the tow-line being,
formed into two branches at the front end, and the,
horses attached one behind the other. The first horse
has blinders, and the boy rides on the hinder horse and. “
guides both. The horses are changed every 4: miles,
after a run of from 20 to 25 ‘minutes, and they make
3 or 4 stages per day. When two boats pass, the
horses of one boat stop just before they come up to
the horses of the other boat, and a boatman takes the
tow line 05 the hook and holds it to prevent it from
coming in contact with the other boat, which passes it
at full speed. The fares are a penny a mile in the
first cabin, and three-farthings, in the second. This
plan has now beenin operation for many years on the
Birmingham canal; the horses go at a gallop, and
this speed is not found to injure the banks of the
canal. Therelhave been’ several proposals to propel
the boats by means of steam; but the weight of steam
machinery would require the moving power to be
greatly increased, and canals as they now exist are not
adapted for increased velocity. With swifter boats
there ought to be no interruptions from locks or from
the contractions offered by tunnels and bridges, and
slow and'heavy craft would also interfere. _ John
Lake has recently taken out a patent for combining
a railway and steam power with the advantages fur-
nished by the water-way. Trains of boats are to be
passed from one level to another byvmeans of inclined
planes. An account of this invention, illustrated by
numerous diagrams, is given the Mechanics’ Maga-
zine, Nos. 1508,; 1509. It resembles the method
adopted on some of the American canals for simplify—
ing if not superseding the system of locks. For
example, on the Morris canal there are 22 inclined
planes. Each plane is a kind of _ railway with an in-
clination of 1 in 21, the rails being of iron, and ex-
tending for some distance into the lower pound, and
at their upper extremity terminating in a kind of lock-
chamber. 0n this railway is a timber carriage, sup-
ported by a truck at either end, sufficiently large to
carry one of the canal boats with its cargo of 30 tons;
In raising a boat the carriage is run down upon the
318
NAVIGATION INLAND.
railway into the lower pound, and passed under the '
boat, which being secured by chains, the whole is
drawn ‘up the incline by machinery into the lock at
its upper extremity, the lower gates of which are
then closed, and the water being’ admitted from the
upper pound, the boat is floated off the carriage,
and pursues its journey on the canal. A boat‘ is
lowered by a converse, arrangement. A ‘similar con--
trivance to the‘ ‘above; wasintr'oduced by Mr. William
Reynolds‘, ‘on the. Shropshire canal many years ago.
One of these inclines ‘is 600 yards. in length, with a
perpendicular-rise joff1=26 Zfeet :i another incline rises
207 feet inailength of 350‘yards."
Some remarkable contrivances have been made of
late yearsI-forisuperseding locks, among which we must
refer to ‘the mechanical lg‘? invented by Mr. James
Green, and applied by him on the Grand Western
Canal. In this arrangement two cradles are sus-
pended from the extremities of a chain which passes
over the rim of a large wheel moving on a horizontal
axis. The two cradles are nearly filled with Water,
and counterpoise each other.
In passing a boat from a higher to a lower pound.
A one cradle vis raised to the higher level; the gate of
the cradle and the end gate of the upper canal are then
removed; ' the boat is floated into the cradle ; the
doors or gates are then-lowered into the grooves in
which they‘fit, so as to close securely the ends of the
channel and the cradle. The cradle and boat are then
let down to the lower pound, into which the boat is ad-
mitted by lifting the gates out of their grooves. While
the loaded "cradle is being lowered, the other cradle,
containing water only, rises :~ the two cradles, how-
ever, still continue to ‘counterbalance each other,
since the boat occupies-a considerable space in the
cradle, which 11nd ‘previously been filled with water,
but‘which, as’ the Lboatpa's‘sed into it, escaped into i
the ~ upper canal, and the ‘weight of water thus dis-
placed is equal to that of the boat itself; so that,
although the cradle has‘ received the additional weight
of the boat, it has lost the same weight of Water, and
consequentlyv the two cradles balance each other.
But, in order to allow the boat to descend, water is
gradually allowed to escape from the cradle contain-
wateronly. The raising of a boat from alower to
an upper ‘level is of course equally simple. The ad-
vantages of this contrivance over locks are, a saving
in‘ the first cost of construction, and in the time and
quantity of water required. Mr. Law states 2 that
a ‘boat can be raised or lowered through 46 feet, the
height of a lift, in three minutes; whereas, on the
"system, five‘ or ~six locks would-be‘ required to
attain the) same lift, ‘the ‘time in passing- through’
which‘would be about "half an hour. ' As to the
water" expended (without taking into account that

‘ f(1"?)3-"Ai1'‘“in'cli'iied plane‘; for passing boats‘ from'iioneilev'el to
another.linemen-by 1L; Underhill, is. ‘represented. and ‘deer
scribed inwthe article- Cfazzals, in..Hebert’s Engineer’s and Me-
entertainers;- lsvasé W .
('2) Rudiments-of Civil Engineering, Part 'I'I.,5 published ‘in
Wealefs Rudimentary ‘Series. :11}; this valuable little work :is a;
tolerably-full description-OfiMr. Green’s liyft, aecompaniedlby two
maseaaéeagraeags. ‘

lost by leakage and in working the lift), a quantity
equal-to the weight of the boat passes up or down
the lift in a contrary direction to that of the boat;
so that if the trailic in opposite directions be equal,
tneupper level will lose no water.
Avery complete and apparently eificient canal lift
has recently been invented by Mr. Archibald Slate, of
the firm of Oochrane & Company, Woodside Iron
Works, near Dudley. ,The conditions required in
this equz'Zz'Z/rz'am lgfl, as it is ,very properly called, are,
that--theboats {float in water during transfer; that
gates orjsluices in the main line of the canal be en-
tirely dispensed with; and; thirdly, that the boat be
transferred from one level to the other, without loss
of water, or the use of more power than is necessary
to overcome the friction ofi'the. machinery. .
The lower level of'thegcanal‘ is ‘,divided into two
branches, or arms, LIP, ,L 1?, Figs-‘1511, 1513, which
are carried along each side of the upper level U 1?, to
a sufficient length to receive an ordinary canal boat.
The depth of each branch is sufficient to allow a
boat 0 B, with a full load, to float over the ends of an
iron caisson or tank A, filled with water, and suffi-
ciently large to float a loaded boat. Over these
branches is a timber or iron framework, upon the
top of which, at points immediately over the upper
and lower branches, are fixed rails in a, on which are
placed carriages KK, containing a series of wheels,
over which run the chains employed for lifting the
caissons. At the bottom of the branches, on the upper
and lower level, are placed the caissons A, which are
carried by straps attached to crossbearers, and sus-
pended by the chains immediately under the framework.
On one side of the framework is suspended the large
shaft s s, carrying the four drums 1) 1), on which the
suspending chains wind and unwind in the operation of
raising and lowering the caissons; the two sets of
chains being wound on the respective drums in oppo-
site directions, so that when one caisson is raised, the
other is at the same time lowered. On each end of
this shaft s, is a hearing or journal, which is grasped
by an eye or strap, in which it can revolve; to these
straps are attached the ends of the equilibrium con-
necting chains L L, the other ends of which are fixed to
the cams c 0'. These cams are keyed fast on the shaft
s’, and on the same shaft are also keyed 2 other
cams, to which is attached by 2 chains the balance
weight cw. On the same shaft are keyed a large
wheel, and 2 drums, to which are attached, on op-
posite sides, the 2 water buckets BB’, for the purpose
of aiding, if required, ‘the manual power in working
the lift. The balance weight cw is nearly equal to
the weightr'of the caissons in the'water, when working
through’ the shortest‘ leverage of the cams; the
caissonsbeingfalloiwed a little weight in excess, in
‘ orderfthat-they‘may freely sink to the bottom of the
water; ‘The balance weight, when acting through
the longest leverage (as shown by the dotted lines),
' is equal’ to"_ balance the caissons when out of the
WatBi‘Qend £1111," Ofwater ; this weight of the caissons
beingathe same‘ under all circumstances, 0.11. account"
1 of the relative displacement of water, whether they.
NAVIGATION INLAND.
31,9,

Fig. 1511.
contain a loaded boat or an empty one, or are merely
filled with water without any boat. The form of the
cams between these two extreme ‘points is regulated
by the form and‘depthof ‘the caissons, '
The following is the action of the lift z—Supposing
2 loaded boats approaching the lift, one on the upper
and the other on the lower level of " the canal (the
same description applying to empty boats, or to a
single boat), each boat is floated into a position over
the sunk caisson. The caissons with the boats float-
ing in. them are then raised out of the water by
applying ‘power to turn the shaft s’, by which the
chains are wound on the cams, causing the upper
shaft s, with the drums and suspending chains, to
move down in the framework to the position shown
by the dotted lines, Fig. 1511, vthus raising the caissons
and boats out of the water; This operation may be
performed either by manual’vpower orby means of the
water buckets B B’, by turning on water from the
upper level into the descending bucket, and letting

END ELEVATION OF MR- SLATE’S CANAL LIFT.
out the water by a valve when the bucket reachesthe
bottom. The varying weight of the caissons, as they
are being raised from the bottom to the surface, and
‘then out of the water, is allowed for, so as‘ to, preserve‘
the equilibrium throughout the operation, by the _
varying leverage of the balance weight actingupon
and. through the 41 cams; so that the power .has no
‘ more than the friction of the machinery to overcome.
Having lifted both caissons out of the water, that
which, is required to descend to the lower level is
moved across the canal, by means of the railway Rn.
on the top of the framework, in, a manner similar to
that of an. ordinary traversing crane, until it is sus-
pended over the lower branch of the canal, ready to
descend, as shown by the dotted lines. When in
this position, the equilibrium is disturbed by allowing
the water to escape from a small partition in the
lower caisson; the shaft is also caused to revolve, and
this by unwinding the chains attached to the descend-
ing caisson, and up the ascending one, carries
sac
NAVIGATION INLAND.
vf—‘Lfn [L -|- a I H
____\h/ ' lv
m
“*1 r \ film‘
.4/


-_-__-.-
$
a
‘raw
'|
i"!
I



\
‘UM’!
Fig. 1512.
them to a relative position opposite to
that from‘which they started; and they
are stopped at the proper point by the
adjusted length of the chains. The cais-
son which has been raised from the lower
level is then moved as before,_by means
bf the railway, across the bank of the
canal, and suspended over the upper
branch; the power again applied to the _
shaft conveying the cams with the balance
weight; ‘and the caissons are simulta-
neously lowered to the bottom of the
canal, vand the boats, floated over their
ends, proceed on their journey.
In this plan there is obviously no
‘waste of water; since the water con-
sumed' in the‘ upward trade is equal to
the'itonnage of the ascending trade; and
the opposite direction the water sup-
plied to‘ the upper‘pounds of the canal is
equal to the tonnage of ‘the descending
trade; so that aweight of water equal
‘to ‘ the whole downward tonnage will be
‘transferred from the lower to the higher
levels of the canal. The difference of the
levels cf-thev two branches of‘ a canal to-
SIDE ELEVATION.


---.._
.__
~_~
:
i‘?
‘V




which this equilibrium lift may be applied, is
limited only by the strength of materials and the
convenience of working.
In the present system of locks, the amount
of trafiic on canals is limited to the supply of
water, and this in many cases is not sufficient
for the ordinary traflic; so that any reduction
of the present rates of carriage on canals under
the present system becomes hopeless.
This equilibrium lift may be made single or
double. In its double form, as shown in the
figures, it is estimated that it would pass one
boat up and another down in about 3 to 5
minutes, according to the height of the lift.
The value of this lift is its capacity for an
almost unlimited amount of traffic, without any
expense of water. Supposing the proposed plan
to be applied to those canals where a number of
locks, from 16 to 30, are situated close together,
- the loss of time to every boat in passing such a
series, is from 2%— to 5 hours; whereas, if one or
two lifts were applied instead, the whole time
1 required for a boat to pass would be only from
10 to 20 minutes.
' of the lift, the inventor states that for a height
With regard to the expense
of about 2a feet or 3 ordinary locks, the lift
would be as cheap as locks: for a less height
the comparative expense would be greater; but
for a greater height, within reasonable limits, the
lift would be considerably cheaper than locks;
each additional 6 feet above the as feet costing
from 2001. to 250i. In cases where it might
I
i
l
o-_~.¢ -- o .-_ _-
ron'rrox or new‘.
fig-1513.
NEEDLES.
" 321
c; Breadth.
0
Name of Canal. =5 ‘2 s g a‘ Engineers.
at‘ E”? g- § "g.
3 s 3.2 E“ 5 r5’
ENGLISH. feet. in ft in.
_ Sankey Canal 1755 12 48 5 7
Leeds and Id- . .
verpool ....... 1770 1081 42 27 5 0 Brmdley"
Basingstoke 1778 37 38 5 6
Thames and .
Severn _______ 1783 30 42 30 5 0 R.Whitworth.
Gloucester and ,
Berkeley .... H 1793 16:21 70 18 O Telfoid.
_ Grand Junction 1793 90 43 -5 0 Jessop.
K222i: 1794 57 44 24 5 0 Rennie.
Aberdeenshire.. 1796 18% 23 3 9 Capt. Taylor.
Thames and
_ Medway....... 1800 8% 5O 28 7 0
l(ilaledonian .... .. 1803 23 40 20 0 Telford.
ye or Royal 0 _ Royal Engi-
Military....... 1807 30 36 9 0 l neers.
AMERICAN.
Champ1ain....... 11 40 28 4 0
Schuylkill -Na-
idgafion ..... a} 58 36 22 3 6
Morris 101 32 20 4 0
Pennsylvania 2.764 40 28 4 0
Erie 363 40 28 4 0
be desirable to ‘transfer the boats through a great
height, they might be passed at one lift through a
shaft into a tunnel below, at any depth that might be
required.
Throughout this description the loss of water is
said to be nothing on the supposition that the lift is
worked by the boatman’s horse, or by manual power;
but if water he used to work it, there will not in any
case be required more then 10 per cent. of what is
used in the present system of lockage,‘so that the
results may be said to be practically the same, as no
canal can possibly increase its trade tenfold.
The following table gives the length and dimensions
of a few of the English and American canals :—-



NEEDLES. The manufacture of needles in an-
cient times, or among uncivilized nations at the
present day, exhibits a rude attempt to form, in
bone, ivory, or bronze, an instrument by which the
sewing or stitching together of garments could be
effected. The Esquimaux women, with their clumsy
needles of bone, and with thread formed of the sinews
' of the reindeer, or the swallow~pipe of a species of
seal, split into different sizes, manage to sew and
stitch together with considerable neatness their deer-
skin dresses and their water-tight boots and shoes. A
rude kind of needle or bodkin, either of bone or ivory,
has been found in British barrows’; while needles of
‘bronze, both for sewing and knitting, are preserved
in museums, ‘and are mentioned by Pliny as having
been in use in his day. The early history of needles
in our own country appears to be lost, but the intro-
duction of fine steel needles, called “Spanish needles,”
and their manufacture in England, in the time of
Queen Elizabeth, by Elias Growse, a German, are
chronicled by Stowe, who also states that, in Queen
Mary’s time, “ a negro made fine Spanish needles in
Cheapside, but would never teach his art to any.”
After the death of this negro (who by another writer
is called “ a native of India”), the art appears to
have been lost sight of, but was again recovered in'
VOL. II.

1650 by Christopher Greening, who settled, with his
three children, at Long Crendon, in Buckinghamshire.
It must not be supposed, however, that the articles
then called “fine steel needles” were more than a
rude approach to the form and perfection of needles
at the present day.
The English‘ needle-manufacture is carried on prin-
cipally at Itedditch, a picturesque village in Worces-
tershire, situated about 14 miles from Birmingham.
The- circumstance of this village having become the
seat of the manufacture is unaccounted for: no local
traditions, as far as we could ascertain, assign a cause ,
for it ; yet' from this obscure place, in the midst of an
agricultural district, a large portion of Europe and of
the British colonies, as well as our own country,
is supplied with needles.
There are about a dozen principal factories or
needle-mills in Redditch, in which the various pro—
cesses of the manufacture are carried on. These fac-
tories are, like most others, large, well-lighted build-
ings, supplied with steam or waterpower, for giving
motion to the wheels and apparatus concerned in the
grinding and polishing of the needles. Many of the
processes are, however, done by hand, and some of
them at the cottages of the workpeople,——processes
which enhance the value of the raw material in a
wonderful degree, so that some of the finest needles
are really “ worth their weight in gold.”
The raw material, as received from Birmingham or
Sheffield, consists of soft, clean steel wire, in coils of
various sizes and weights, and numbered to cor-
respond with certain slits in a small steel plate, called
a guage. Of these numbers, 1 represents a wire g‘,- of
an inch in diameter, and so on in diminishing propor-
tion until 12 represents a wire ,30th of an inch in
diameter. The first process in the manufacture is to

take the wires from a number of coils ‘of equal dia- '
meter, ‘and, collecting them in the hand, to insert
them between the blades of a pair of shears, and so
cut them into successive lengths, each length being
sufficient to make two needles. The shears are fixed
to the wall in the cutting-room, and are pressed
together by the workman’s thigh. The number of
pieces collected depends on the size of the wire: sup-
posing the size No. 6 is being made, enough wire is
uncoiled to cut up into 25,000 or 30,000 pieces, each
piece being about three inches long, or the length of
two needles. The pieces are all more ‘or less bent,
from ‘having been coiled, and they must be straight-
ened before any other operation takes place. For
this purpose, several thousand pieces are collected
within two broad and heavy rings, and are thus placed
on a shelf in the furnace, and heated to redness.
They are then lifted out, and placed on an iron plate,
still retaining their position within the rings. A
workman then takes what is called 'a smooth file, the
form of which is shown in 1514, and placing
the centre portion in the space between the rings,
rubs or rolls the wires backwards and forwards, until
by their friction against each other they are effectually
straightened. The noise resembles that of filing, but
soon changes from a grating sound to a more subdued
Y
322
NEEDLES.
tone, which informs the workman that the necessary
ml/émy, as this process is called, has been effected.


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us ' '
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Fig. 1514.
The next process 'is one which injuriou'sly afi'ects
the health of the operatives; ‘but which may 'be ren-~
dered less hurtful by the adoption of .recent improve-
ments. It consists in grinding the two ends of the
straightened wires uponsmallgrit stones of fromtcn
to twenty inches in diameter, according to the size of
H‘ln'h- I;
1| "up"...
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l \‘if-
a ,_ the tilt‘
I Na
' ‘am’. .
y < -.—'~:;_j"'""* ‘
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T .. "HM is“ ,\\.~
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'wiiht l “l r ---r-’-”‘,.-5'-':’ ""a y ' ‘.lj r222:
" 4”’ l‘citltéaefr
" ; 17%}211 -
_ /-
' 1,”
Fig. 1515.
POINTING THE WI RES.
the needle. These grindstones are set in rapid
motion, while a workmen seated before each, takes a
number of wires in his left hand and spreads them
out, keeping-‘them parallel byplacing the right hand
upon them Lina peculiar way, and at the same time
moving it so as-t-o make all the wires rotate'backwards'
and forwards ‘in order that a perfect cone or point
maybe for—med. Sometimes a piece of stout-leather,
called a thumb-piece, is used in pressing the wires
against the stone. Occasionally he adjusts the points,
and also ‘dips them in- water to keep them cool, for
when the 6points --are in contact with the stone the
friction produces heat and a brilliant stream of sparks.
The minutelparticles of grit and of steel which thus
fly off into the air form a dust which enters the work-
man’s lungs and produces an affection of the breath,
,-
known as grz'nder’s asz‘lzma. This disease, when
aggravated by intemperance, as is too often the case,
becomes early fatal, so that the man is old at thirty,
and frequently dies at thirty-five or forty. Several
ingenious inventions have been contrived to make his
trade less hurtful, but in the great majority of in-
stances the grinder refuses to adopt them, under the
idea that his wages will be lowered if the risk is
lessened. Thus-he voluntarily destroys 'his health for
the sake of high‘ wages, using no other precaution
than a handkerchief 5tied over his’ mouth, and forget-
ting that skill of the kind he possesses-would always
meet with a fair reward, and'that freedom from much
pain and suffering would also‘iresult from the use of
the means set before him. One of these means is
afforded by a mask for covering the mouth and nos-
trils, in which two or three layers .of erape or muslin
are stretched over a slight wooden frame, which is
studded with magnets. These attract the particles
of steel in the passage to the mouth, while the crape
filters the air of particles of grit. As the mask be-
comes loaded with particles it is necessary to take it
off once or twicein the course .of anjhour and give it
a few gentle taps. This apparatus is tolerably effec-
tive, and‘has been invented more than thirty years, yet
the grinders. continue to reject it for the reason above
named. Anotherpiece ofapparatus is the ventilating
shaft noticed under GU'rLsnY, leading from .the grind-
stone through the wall of the grinding room into the
open In this pipe a strong .current of air is
generated by a fan, the effect of which is to draw
away the particles of steel and grit from .the grind-
stone as soon as .:they are formed, and convey them at
once into the open air. But this was also neglected.
It is therefore with .sincere pleasure we record the
humane conduct of the principal needle manufacturers,
who seeing the workmen themselves thus suicidal in
their conduct, have'taken steps for doing them good
against their will, and have introduced ventilating
shafts for clearing the air of this pernicious dust.
When the needle, or pair of .needles, leaves the
grinder it is a straight piece of soft dingy wire, pointed
at each extremity. The next process is the formation
of two eyes in the centre. The eye of a needle con-
sists of a small groove and a perforation, .and these
must be formed by successive and cautious opera-
tions, that the wire be .not damaged in the process.
The grooves, and a small indentationatthe spot in-
tended for the hole are first produced by the stamp-
ing machine. This is a bed of iron containing the
under half of adie or stamp,~supported on a heavy
block -of stone. Above thisis aham-mer of about
‘twelve porunds weight, containing the ether half of
the die, and capable of being raised by pressing a
lever with the foot. Theworkman, holding several
wires, or blank needles, drops one eta time upon the
iron bed, pushing it up against a piece of metal so as
to determine the length -of {the needle; then, raising
the hammer. with his f-foct, lets it fall with a smart
blow. The two raised faces of the die produce two
opposite indentations on the wire, bulging out a por-
tion of its substance. Although the stamper has to
. NEEDLES.
323
adjust and stamp each wire separately, yet he can
operate upon two thousand wires, equivalent to four
thousand needles, in the course of an hour.
The task of piercing the eyes is committed to a
number of boys, who work small hand-presses pro-
vided for that purpose.
Spreading the wires out
like a fan, the boy places
one of them in a notch
formed in a small iron
slab,Fig. 1516, bringing
the middle of the wire to
the middle of the press.
The upper arm of the
press contains two steel
points or cutters, of the
exact size of the eye, which fall over corresponding
holes in the die. The boy holding his head close to
his work brings this arm down and cuts or punches
out the eye. As each wire is pierced the boy shifts
the fan of wires so as to bring a fresh wire under the
punch. This is called eyeing the needles; but in some
cases it is done in a different manner. For some
kinds of needle the wires as soon ‘as they are pointed
at the two ends, are out in the middle by means of


the upright shears already noticed, and are then laid
parallel to each other in small wooden boxes, and
transferred to the head flattener. This is a whrkman,
seated at a table, with a cubical block of steel before
him, on which he flattens the head of each wire sepa-
rately, with a small hammer, holding the wires spread
out in his left hand, and presenting them in rapid
succession, so that each blow of the hammer flattens
one needle. This blow also hardens the ends of the
wires, therefore it is necessary to soften them by heat-
ing and then slowly cooling, before they are given to
the pz'ereer. This is generally a child, who placing the
ends on a block of steel applies the point of a small
punch to each, and pierces the eye by a smart tap of
the hammer; the needles are then turned over and
the process repeated on the opposite side, that both
sides of the eye maybe alike. The eyes have next to
be trimmed by another ‘child, who inserts a punch in
the eye, and while- it is still sticking in it, taps the
needle on each side with a hammer, so that the
eye assumes the shape of the punch. The needle
is then taken between pincers and the headrested
in an angular groove cut in a piece of hard steel,
when, with a single stroke of a small file on the
two opposite sides of the head, the groove is formed.
With a file also the head is rounded and smoothed.
This finishes the shaping of the separate needles,
but the forming of grooves‘ and eyes in the double
needle, as first described, is the most expeditious
1
2 ‘ff-3k
3 M
Fig. 151?. '
and economical method, and that which is generally
adopted. Fig. 1517 represents, 1. The straight wire,_

pointed at both ends. 2. The same, flattened in the
centre and grooved. 3. The same, with the eye
perforated. The bur produced on each side of the
eye in the process of stamping is filed off, not sepa—
rately, but from a num-
her at once, which are
ingeniously spitted on -
fine wires, Eig. 1518,
run through each line of
eyes with great rapidity
by children. When the
whole have been acted
upon by a flat file, the
separation of the needles
is effected, not separately
but by bending the whole line of needles backwards and
forwards between the two spits, thus producing two
separate rows of needles, each row spitted on a wire.
The points of each row
are then grasped in a kind
of hand vice, Fig. 1519,
and the heads filed to
their proper shape. After w '‘
passing through all these
processes some of the
needles have necessarily become bent; they are there—
fore sent to the soft straightener. This is generally a
woman, who, placing a number of the needles (which
are still in the soft state) on a flat steel plate, rolls
them backwards and forwards one at atime by means
of a smooth steel file turned up at each end, so as to
present a convex surface to the needles. Two or
three. turns of the file to each needle are snficient to
straighten it,‘a'nd the woman can thus operate on a
thousand needles per hour.
Still, however, the needles are far from complete,
for they are black, dingy, and soft. In order to
harden them, they are spread by means of 2 little
trowels, in a thickish layer on narrow plates of iron,
and placed on a shelf in the furnace. When they
have reached a red heat, they are taken out, and
suddenly cooled by being plunged into cold water or
oil. This makes them too hard and brittle for use;
therefore, they are next tempered, that is, when taken
out of the water and dried, they are again heated, but
not to so high a temperature, and are allowed to cool
gradually. The method of heating is on an iron
plate with a fire beneath, and the needles are kept in
constant motion with small iron shovels until a blue
oxide forms upon them, when they are considered to
be of the proper temper, and are instantly removed.
In the-process of hardening, some of the heedles again
become bent; so that the next process ‘is hard or
hammer straightening, which is usually done at the
homes of the workpeople. The needles are rolled by
the finger on a smooth steel slab, to detect those which
are bent, and so do not roll truly; these are picked
out, and straightened by hammering on a small anvil.
The needles being hardened, have next to be secured
or cleaned. This is effected, principally, by mutual
attrition. They are made up into bundles of 40,000
or 50,000 in the following manner :-—A number of


Fig. 1518.


Y 2
32h
NEEDLES.
strings are laid'across a wooden tray open at both
ends, Fig. 1520 ; upon these strings is placed a stout
piece of canvass,
and within the
canvass the nee-
" dles are arranged
in heaps in the
direction of their
length, but with-
out any distinction as to heads or points. A small
quantity of emery, oil, and soft-soap is sprinkled
over them, and they are then rolled up in a bundle,
and tied up temporarily. A man then winds a piece
of strong twine round the bundle in a tolerably close
coil, removing the string as he advances with the
twine, and forming at length a compact bundle 2 or
3 feet long, and 3 or 41 inches thick. When a
number of such rolls have been prepared, they are
placed under scouring-machines, Fig. 1521, which




I - . .
,.'=.=_-= "
T‘:-
‘-
“
Tat‘


ll?
rnlhllnl m1 '
t '->—-—



a {11'

.______,--_____
.Fz'g. 1521.
consist of troughs containing weighted slabs, under
which the bundles of needles are moved backwards
and forwards in the same way as the rollers of a
common mangle. The rubbers‘ work at the rate of
20 or 30 movements in a minute, pressing heavily
on the rolls, and causing the needles to rub over and
over each other, so that by constant friction, aided
by emery, oil, soft'soap, and polishing putty, during 50
or 60 hours, a bright surface is obtained. The rubbing
is suspended every 8 hours to renew the canvass,
which becomes worn through, and to add fresh polish-
ing putty and oil, the needles being also washed in
soap and water on each occasion. For the best
needles this process is carried on during '7 or 8 days
in succession, and the breakage is often considerable.
The bright and clean needles are next sent to the
Might-shop, where they are shaken in long tin trays
till they all lie parallel, then made up into long rows
or heaps, and passed to a little girl called the header,
whose task it is to turn all the heads one way. Dif-
ficult as this may seem where 40,000 or 50,000
needles are concerned, it is done with a degree of
rapidity and case which astonishes by its simplicity.
The child has a piece of rag or soft leather wrapped
round her fore finger, and pressing it against the pile
of needles, all the points which happen to lie that
way run into the rag, and retain sufiicient hold to
allow of her drawing the needles in this way out of
theheap, and depositing them in a new pile, so that
when the work is done, the needles form two large
a
heaps with the points lying in opposite directions.
Broken or defective needles are rejected from these
heaps, and the remainder are subjected to the delicate
operation of having the sharp edges of the eye removed,
which are so apt to cut the thread. This is called
drilling, and in order to its proper performances, the
needles have again to be annealed about the eye.
This is done by placing them on a steel plate with
their eyes projecting over its edge. A red-hot plate is
then cautiously brought near them, and when they
assume a dark blue colour, the proper temper is
acquired. The drilling is performed by young women
seated at a bench opposite awindow, and having each
a small three-
sided steel drill
in rapid revo-
lution before
her. The driller
taking up a
few needles,
and spreading


.I . ' ‘.-. > "rt
.. , _
.1 \
‘I0 \ ‘ l'l ““
‘ ___-——'..—"‘
1 ,\ _._-
r. r A: .»

.a . a ‘ lll .;
them out like , V _ '3 Immummllflllll
a fan, brings 75"“ I!" W
them in succes- ~. 5. ill l
sion under the i1 V
action of the K
flail-ME‘ 2
drill. Each eye
is first counter-
sunk, that is,
its sharp edge
is bevelled off
with the drill,
so as to join the
groove in a rounded instead of an angular manner.
The rest of the eye is also drilled on both sides,
and made perfectly smooth. This drilling, which is
of modern invention, is a great improvement in the
manufacture; but it is almost painful to witness,
from the peculiar constrained posture, and rigid look
of the persons employed on it—so necessary is it in
this delicate operation to prevent the least tremor or
unsteadiness of hand. Gold-eyed needles are pro-
duced by dipping the head of the needle in ether
containing gold in solution, which immediately at-
taches itself to the steel. This merely serves to
increase the cost of the needle without adding to its
utility.
After the drilling, the needles have their points
finished on a small and rapidly rotating hone-stone.
They are then passed to the polisher, who polishes
them on wheels of wood covered with buff leather
slightly smeared with polishing paste. They are then
ready for papering, for which purpose they are
counted intoquarters of hundreds, folded up in blue
paper, and labelled. These papers are then made up
in bundles of 20 each, and these again into square
packets, which may contain 20,000, $0,000, or
60,000 needles. When intended for exportation,
they are packed ‘in soldered tin cases. The pro-
cesses above described apply to the fine sorts of
needles, for the common kinds several of the finishing
operations are omitted. At the mill visited by the

.Fig. 1522. DRILLING THE EYES.
NEUTRAL SALTS—NICKEL.
325
writer, 100,000,000 fine needles are made in the
course of a year, while the total amount produced at
Redditch and the neighbourhood, is 7 0,000,000 per
week.
NET. See Wnxvrne.
NEUTRAL SALTS. When an acid and a base
are combined in certain definite proportions, they
ueulrulize each other’s properties, so that neither the
acid nor the alkali, if the base be an alkali, exerts any
action on test-papers: the result is What is called a
neutral salt. The proportions, or cquiuuleuls, as they
are called, in which bodies neutralize each other are
very variable. “ Some acids have very high capacities
of saturation; of others a much larger quantity must
be employed to neutralize the same amount of base.
The bases themselves present also similar phenomena.
Thus, to saturate 4719 parts of potash, or 116 parts
of oxide of silver, there are required 4009 parts of
sulphuric acid; 5406 of nitric acid; '7 5'41 of chloric
acid; 16636 of iodic acid; and 51 of acetic acid:
numbers very different, but representing quantities
which replace each other in combination. Now, if a
quantity of some base, such as potash, be taken, which
is represented by the sum of the equivalents of potas-
sium and oxygen, then the quantity of any acid requi-
site for its neutralization, as determined by direct
experiment, will always be found equal to the sum of
the equivalents of the different ‘components of the
acid itself. Thus 39'19: the equivalent of potas-
sium + 8 : the equivalent of oxygen : 47 '19, the
assumed equivalent of potash ; and 47 '19 parts of
potash are found to be exactly neutralized by 4009'
parts of real sulphuric acid, or by 5406 of realnitric
acid. These quantities are evidently made up by adding
together the equivalents of their constituents :—
1 equiv. nitrogen = 1406
oxygen = 40'
1 equiv. sulphur = 1609
3 ,, oxygen = 24. 5 ,,

1 equiv. sulphuric acid 4009 1 equiv. nitric acid 5406
The same is true if any acid be taken, and the quan-'
tities of different bases required for its neutralization
determined: the combining number of the compound
will always be found to be the sum of the combining
numbers of its components, however complex the
substance may be.” ‘
NEUTRALIZATION. See ALKALIMETRY.
NEUTRIA. See HAT—Fun.
NICKEL (Ni 2957), a metal of a greyish white
colour, with remarkable magnetic properties. which it
loses on being heated to 660°. It is ductile and
malleable : a Bavarian coin has been struck in nickel,
and the impression of the die is said to be very perfect.
The sp. gr. of nickel varies from 8'27 to 8 40 when
fused, and after being hammered, from 8'69 to 90.
It has a high melting-point, and is but little acted on
by dilute acids. Heated in contact with air, it ac—
quires various tints like steel, and becomes soon
covered with a green oxide. The pure metal is easily
prepared by raising the oxalate to a white heat in a
crucible lined with charcoal. Native nickel is found
in the Erzgebirge in small quantities. Kujj’eruickel

(I) Fownes’ Manual of Chemistry. See also Regnault, Cours
de Chimie, ii. p. 50, 2d Edition. ‘

or copper nickel is an arseniuret, and is tolerably
abundant; but some“ of the arsenic is occasionally-
replaced by antimony. Copper nickel is usually asso-
ciated with the ores of copper, silver, and cobalt, and
is chiefly obtained from the mines of Saxony. The‘
old German miners regarded it as a kind of false
copper, and applied the term uiclsel to it by way of
contempt. It has also been found in Cornwall. Among
the other ores are uic/relgluuce, an arsenical ore, found
massive and in cubical crystals; uzlziz‘e uiclcel, another
arsenical ore; uic/cel slilziue, an antimonial sulphuret
of nickel; uulimouiul uiclccl, containing no sulphurz'
it is of a pale copper colour. Nic/ael pyriies is a sul-
phuret, of a brass yellow colour, containing 64 per‘
cent. of nickel: uiclteliferous pduriles is a double sul-
phuret of iron and nickel, of a bronze yellow colour:
there is also a sulphuret of nickel containing bismuth. '
An alloy of iron and nickel forms a principal metallic
ingredient in most aérolites or meteoric stones.
Nickel forms two oxides only, one of which is basic.
The protoxide, NiO, may be prepared by heating the '
nickel to redness, or by precipitating a soluble salt
with caustic potash : the apple—green hydrated oxide
is to be washed, dried, and ignited: the resulting
protoxide is' an ash-grey powder, freely soluble in
acids, whichlit completely neutralizes: the salts have
usually a beautiful green colour. Sulphate of nickel
is the most important of the salts of nickel. It forms
green prismatic crystals, containing '7 equivalents of
water, which require 3 parts of cold water for solu-
tion. It forms beautiful double salts with the sulphates
of potash and ammonia.
Pure salts of‘ nickel may be prepared on a small scale
from crude speiss, or kupfernickel, by the following
process a "‘ The mineral is broken into small frag—
ments, mixed with from one~fourth to half its weight
of iron filings, and the whole dissolved in aqua regia.
The solution ‘ is gently evaporated to dryness, the
residue treated with boiling water, and the insoluble
arseniate of iron removed by a filter. The liquid is
then acidulated with hydrochloric acid, treated with
sulphuretted hydrogen in excess, and after filtration
boiled with a little nitric acid to bring back the" iron
to the state of peroxide. To the cold and largely diluted
liquid, solution of bicarbonate of soda is gradually
added, by which the peroxide of iron may be com-
pletely separated, without loss of nickel salt. Lastly,
the filtered solution boiled with carbonate of soda in
excess yields an abundant pale‘ green‘ precipitate of
carbonate of nickel, from which all the other com-
pounds may be prepared.”—-Fczcues.
The nickel of commerce is obtained chiefly from
kupfernickel, nickeliferous pyrites, and from the speiss
obtained as a secondary product in the treatment of
the nickeliferous ores of cobalt. As there is a great
demand for nickel in the manufacture of German
silver, some improved methods of obtaining the metal
have lately been introduced. They are kept secret ;
but Mr. Phillips in his Manual of Mineralogy suggests
the following as the process likely to be followed :—
‘l The roasted ore or speiss, after being dissolved either
in sulphuric or hydrochloric acid, to which either
I
326
. " NIELLO—NITRO GEN.
nitric acid or nitrate of soda has been added to per-
oxidise the metals, is placed in large vessels in which
the insoluble matters are allowed to subside. The
clear liquor, after it has cooled, and the copper and
lead which havelbeen precipitated by sulphuretted hy-
drogen, may .be decanted OE, and treated by carbonate
of lime in the form of common chalk, by which the
iron and traces of cobalt will be precipitated, whilst the
greater portion of the cobalt and the whole of the
nickel will remain in solution. After the oxide of iron
thus precipitated has subsided, ‘and the liquor has
been again syphoned off, the cobalt may be thrown
downby saturating the solution with chlorine gas, by
the “addition of hypochlorite of lime, and then adding
carbonate of lime or'carbonate of baryta. The liquor
syphoiiedifrom this solution contains the whole of the
nickel, which may now be precipitated by ebullition
with hydrate of lime, and dried and reduced in the
usual manner.”
As nickel is used entirely as an alloy, it is sent into
' the market in the form of finely divided grains, or
granulations of the size of small beans. [See SILVER,
GEnMAn] - -
NICOTINE. See TOBACCO.
_ NIELLO. Akind of enamelling, practised, accord-
ing to some writers, as early as the seventh century,
but afterwards lost until Finiguerra, an eminent gold—
smith of Florence, brought it into great repute in the
15th century. The art is interesting, as it is sup-
posed to have given the first idea of printing from
engraved plates. It consists in engraving a subject
on gold or silver, and filling the engraved lines with
black or very dark-coloured enamel. In the general
effect of works in niello, there is considerable resem-
blance to damascening, except that in the latter the
engraved lines were ‘filled up with the precious metals,
while, in the'foimer, a paste or enamel was made use
of. This enamel was a compound of silver, copper,
lead, sulphur, and borax, forming a dark-coloured
paste, which was carefully worked into all the lines
of the engraving, and fused, by heating the plate.
It contrasted favourably with the bright surface of
the silver chalice or other article so decorated, pro-
ducing an effect not unlike that of a copper-plate
engraving, or of a daguerreotype. This kind of work,
at one period, constituted the favourite means of
adorning, not only all kinds of vessels used for sacred
purposes, but also sword-hilts, knife-handles, and
other articles in which the precious metals formed
the basis to work upon. In the Museum, at Florence,
is the most valuable specimen of ancient niello now
existing, being a plate for a pix executed by Fini-
guerra ‘himself in M5 2. An interesting specimen is to
be seen in the British Museum, consisting of a silver
cup mounted in gold, the ornaments being in niello.
This long-neglected art has been revived and again
brought into notice, by a silversmith of Berlin, named
Wagner, who is now settled in Paris.
c'essful work in niello was sent by the Messrs. Grass,
of Regent-street, London, to the Great Exhibition.
It was a silver gauntlet niello bracelet, designed by
D. Maclise, Esq, R. A., descriptive of “The Promised
\
A very suc-~- '

Gift,” ' “ The Gift Ordered,” and “ The Presentation,”-
interlaced with decorative illustration. This elabo-
rate design was engraved by Mr. J. J. Crew.
Artists in niello find it necessary to take proofs of
their work as it proceeds, and so in ancient times it
is stated that the work was examined by filling the
lines with a black fatty material, and then pressing
a mass of a peculiar kind of clay upon the design, so
as to obtain an impression. This process so nearly
resembled printing, that it is only to be wondered at
that the latter art was not earlier discovered. It is
said that the important secret was at last revealed
by a female accidentally placing a bundle of damp
linen on a niello plate which had been proved in the
workshop of Finiguerra, and which happened to be
lying with some of the black material still remaining
in the lines. The damp linen absorbed the black,
and gave a perfect impression of the plate to the
astonishment and delight of Finiguerra, who imme_
diately instituted a series of experiments which ended
in the discovery of the engraver’s art.
NITRE. See POTASSIUM. \
NITRIC ACID. See N Irnoenn.
NITROGEN (N 14), one of the constituents of the
atmosphere, of which it forms about gths. [See Ara]
It also enters into the composition of a large number
of substances, such as the native nitrates or nitres,
whence the term nitrogen, z'. 6. generator of nitre. It
occurs in coal and a few minerals, and is frequently
found in animal and vegetable substances. It may
be prepared for the purposes of experiment by burn-
ing out the oxygen from a confined portion of air by
means of .phosphorus, or by a jet of hydrogen. There
are various other methods of preparing it, for which
we must refer to chemical treatises.
Nitrogen has no colour, taste, or smell : its density
is '97 2, or a little lighter than air: 100 cubic inches
at the temperature of 60°, and the pressure of 30
inches, weigh 30'141 grains. This gas is not capable
of supporting animal life, and hence it was termed by
Lavoisier, azoz‘e (from d, privative, and (mi, life), a
name which it still retains among French chemists:
it does not appear to have any poisonous properties:
animals die in it from the absence of oxygen, and
flame cannot burn in it‘ from the same defect. Ni-
trogen is not soluble to any extent in water or caustic
alkali; it is, in fact, most remarkable for_ its negative
properties. It is seldom used in its pure state ; but,
being without action upon other substances, it may be
employed for forming artificial atmospheres for pro—
tecting certain bodies from the action of oxygen or
other active gases. .
The compounds of nitrogen and oxygen are of im-
portance. Of these there are not less than five‘ :—-
Nitrogen. Oxygen.
Protoxide of nitrogen .... .. 14 . 8
Deutoxide of nitrogen .... .. 14 16
Hyponiirous acid............... 14 24 I
Nitrous acid 14 32
Nitric __ 14 .......... .. 40
Of these compounds nitric acid is'the most important,
and as it is by means of it that all the others are pre-
pared, it is desirable to notice it first.
NITROGEN; I
327
Nitric acid, N05, is prepared by ‘the'chemist from
nitre or saltpetre, which is a compound of nitric acid
and potash. Equal weights of powdered nitre' and
sulphuric acid are introduced into a glass retort to
which heat is applied: the beak of the. retort is intro-
duced into 'a flask, or'glass receiver, kept cool by a
wet cloth. The sulphuric acid unites with. the potash
to form bisulphate of potash, which remains in the
retort, while the nitric acid combines with the- water
of the sulphuric acid and distils over.
In the manufacture of nitric acid on a large scale,
cast-iron cylinders are commonly used with- earthern
condensing vessels connected by tubes as receivers.
The iron cyl-niders are arranged in pairs, as shown in
Fig. 1523. In front of each cylinder is an opening,


Fig; 1523. nr'raic ACID mos neron'rs.
to which one end of a bent tube, t, Fig. 1524', is luted,
the other end passing into the neck of the first receiver
w. The tube t" from the middle neck is connected '
with the middle neck of the next receiver; while the


Fig.. 15.2%.
SLDE ELEVATION.
tube t” from the third neck passes to a series of two-
necked Woulfe bottles, arranged as shown in Fig. 717,
DISTILLATIONf Thus the two cylinders of each fire
discharge their fumes into two series of receivers,
which are connected together at the commencement
of the series. The cylinders are charged with’ nitrate
of potash, or nitrate of soda, which is also used for
the purpose, by removing the back plates, which,
being restored, a quantity of strong sulphuric acid is
poured in by means of a cast-iron funnel, f, the beak
of which is inserted into- an opening which is- after-
wards closed with a stopple of baked clay. The
joints are then carefully luted, and the heat applied
in a regular manner, until the acid ceases to distil
over. The plates are then removed, and the sulphate
of potash drawn out by means of iron scrapers. The
acid, condensed in the first receivers, is the most
impure: it is contaminated with sulphuric acid carried

over in the distillation-1 This impure acid is employed
in the manufacture of sulphuric acid. The other
receivers contain the nitric acid of commerce. It is
of variable strength, and contains a certain amount
of nitrous acid, and sometimes a little chlorine, if the
nitre contain minute portions of chlorides. The last
receivers in the series contain only a weak acid. At
the commencement of an operation this weak acid is
usually poured into the first receivers, and pure water
into the- last receivers for the purpose of completely
condensing the nitrous vapours. The acid of com-
merce;_thns prepared, is usually sufliciently pure for
most purposes: but it may be freed from chlorine
and sulphuric acid by agitating it with a little concen—
trated solution of nitrate of silver, and redistilling in
a glass retort.
Nitric acid is also prepared on a large scale in glass
or earthenware retorts, arranged in a gallery/Wham,
as shown in Fig. 1525-, in. which the retorts are sunk
\ LEE—1.3
/,
l'llll
ll



Fig. 1525. nrrnru ACID.- GALLERY FURNACE.
in- sand pots s s. The furnace has two fires with one
chimney, furnished with. dampers d at, a. thin partition
being placed between them; 9 is the grate, the fire
from which traverses the whole length of the furnace,
and: heats the sand pots. The fire can be moved into
such a position as will distribute the heat uniformty.
The retorts must be charged with care, to prevent any
sulphuric acid from wetting the necks, for which
purpose a long funnel is used. The receiver adapted
to each retort is kept cool by a stream of cold water,
or a very large receiver is employed, such that the
action of the ordinary temperature of the air is sulfi-
cient to condense the fumes. When the first impure
portions of acid have been collected, fresh receivers
containing water are- substituted so as to keep the
purer’ acid separate.
The- nitric acid of commerce is also called aqua-
fortts, without reference to its strength. That in
common-use contains about two-thirds water : what is
called doahte agua-fortz's contains 4.0 per cent. of
water, and is of the sp. gr, 1'42, its boiling point
being 248°. Acid is commonly met with of a sp. gr.
1'50 to 1'52 ; it has a yellow colour in consequence
of the presence of nitrous or hypon-itrous acid. It is
exceedingly corrosive. When poured upon red-hot
charcoal it produces brilliant combustion, and when
added to warm oil of turpentine it sets it on fire. The
pure acid is quite colourless: it has a sp. gr. of 1517
at 60° Fahr. and boils at 1849. It consists of 54: 06
328
NITRIC ACID.
parts of real acid, and 9 partsiwater: the anhydrous
acid has been unknown until recently M. Deville has
obtained it by the action of dry chlorine on nitrate of
silver,.the utmost care being taken to exclude moist
ture : chloride of silver is formed, and anhydrous
nitric acid evolved.1
before it will attack metals, and its action on lignine,
starch, &c. is much less energetic than that of an .acid
containing more water. There is a second definite
compound of real nitric acid and water, containing
5406 parts of acid and 36 of water: its sp. gr. at 60°
is 1424:, and it boils at 250°. An acid weaker than
this may be concentrated to it by evaporation, and- a
stronger acid may be reduced thereto by loss of nitric
acid and water in the form of the first hydrate.-
Nitric acid is formed in minute quantities by passing
a stream of electric sparks through a confined portion
of air, water or an alkaline solution being present. It
is probable that nitric acid is formed in this _-way
during thunder storms: the lightning striking through
vast masses of atmospheric air may cause the oxygen
and nitrogen to combine in proper proportions, and
this acid, uniting with‘ the ammonia also found in
the atmosphere, may descend with the rain upon the
earth in the form of nitrate of ammonia.
Nitric acid forms with bases an extensive group of
salts, the nitrates, which are all soluble .in water.
This circumstance renders the detection of nitric acid
in small quantities in solution somewhat difficult,
since no precipitant for it can be found. One of the
best tests is its power of bleaching a solution of indigo
in sulphuric acid when boiled therewith. Chlorine
must of course be absent. The hydrated acid is of
importance to the chemist, the pharmist, and the
manufacturer. It imparts .a yellow colour to many
animal substances, and is hence used for producing
yellow patterns upon coloured woollen goods. It is
used as a solvent for tin in the preparation of mor-
dants: it is employed for etching on copper: it is of
importance in metallurgy and assaying. It is admi-
nistered in a dilute form in medicine, and it is an
energetic caustic in surgery. Professor Brande sug-
gests, that if effectually applied to a wound occasioned
by the bite of rabid animals, it might destroy the
poison and prevent its consequences. The remedy,
however, to be effectual, must be. applied speedily
after the injury.
The other compounds of nitrogen and oxygen are,
as already stated, prepared from nitric acid, or the
nitrates. The protoxide ry" nitrogen, or nitrous oa'z'de,
NO, is prepared by distilling pure nitrate of ammonia
in a glass retort: the salt is .resolved into nitrous
oxide and water. It is a colourless invisible gas, with
a faint agreeable odour, and a sweetish taste. Cold
water dissolves about sZ-ths of its volume of the gas;
hence it should be collected over warm water, which
absorbs much less. It supports combustion with an
energy inferior only to that of oxygen. When inhaled
from. a water-proof bag furnished with an ivory mouth-
piece, it produces a strange kind of exhilaration, and
occasionally a strong ungraceful muscular action,
(1) Annales de Chimie, III. Serie, Tome 28. >

Nitric acid requires to be diluted-

accompanied by laughter, which has an unpleasant
unnatural effect, from the eyes not partaking in the
joyous. expression, but being usually rigidly fixed.
This property has procured for nitrous oxide the name
of laughing-gas.
The next compound, ez'nonz'de ‘or dentorez'de of nitro-
gen, also called nitric oxide, N02, is prepared by the
action of dilute nitric acid on clippings or turnings of
copper. A portion of .the nitric acid is deoxidized by
the copper; the metal is oxidized and dissolved by
another portion of the acid. The resulting gas, which
may be collected over cold water, is colourless and
transparent : it does not support combustion; but if
phosphorus in a state of vivid ignition be introduced
into a~~jar of it, it is decomposed, and the phosphorus
burns vividly. The most remarkable property of
nitric oxide is, that on coming in contact with air or
oxygen it produces red fumes, ~which‘are. absorbed by
water. , '
Hyponizfrons acid, ‘N03, is prepared by mixing 41
measures of binoxide of nitrogen with I ' measure of
oxygen: the gases must be perfectly dry, and exposed
to the temperature of zero: they condense into a thin
mobile liquid, which is colourless at that temperature,
but green at ordinary temperatures: it's vapour is
orange red.
Nitrous acid, NO,- The deep red fumes formed
when binoxide of nitrogen is exposed to the air or to
oxygen gas, consist of nitrous acid. By heating
nitrate of lead, the nitric acid separates from the oxide
of _lead,,and resolves itself into oxygen and nitrous
acid. Under the influence of a powerful freezing
mixture, the nitrous acid may be obtained in the liquid
form: it is nearly colourless, but becomes yellow and
red as the temperature rises. At 82° it boils, and
gives off red fumes. This as well as hyponitrous acid
is decomposed by water into binoxide of nitrogen and
nitric acid. Strong nitric acid absorbs its vapour,
and assumes a yellow or red tint, then green and blue,
and as water is added all colour disappears. The red
fuming nitrous acid of commerce is nitric acid im-
pregnated with nitrous gas. Nitrous acid does not
seem to have the power of forming salts with bases,
and hence its title to the term acid has been ques—
tioned.
NITROMURIATIO AOID. See AQUA REGIA.
NUTMEGS and MACE. Both these spices are the
produce of the same tree (Myrz'sz‘z'ea mosennz‘n), a native
of the Molucca Islands, but cultivated in Sumatra,
Java, and elsewhere in the East. It is likewise
cultivated in- several of the West India Islands, but
with less ‘success. The fruit of the nutmeg-tree is as
large as that of our peach; but when ripe the fleshy
part bursts asunder in two halves, showing the stone
(as we should call it in the peach) which contains
within it .the valuable kernel or nutmeg. - But this
stone is itself covered with a membranous kind of
network, of a bright red colour, which is the mace :
in drying-this afterwards becomes orange yellow. The
_ appearance of - the rich brown shell of the nutmeg
covered with the red fibres of - the mace is very beau~
tiful in the fresh fruit. These fibres being removed;
NUTMEGS AND MACE.
329
the shells are dried in the sun or by a moderate fire
until they split, revealing the aromatic kernel or
nutmeg.
Nutmeg plantations are formed in alluvial ground,
or in virgin forest land in level situations. Declivities
are unfavourable on account of the slight hold these
trees take on‘ the soil, and the consequent danger of
their being uprooted during the heavy rains which
occur in tropical .countries. Their culture in Ben-
coolen, which represents the ordinary mode of treat-
ment, has been minutely described by Dr. Lumsdaine,
in a paper originally communicated to the Agricultural
Society of Sumatra, in 1820, and recently republished
in Silliman’s American Journal of Science and Arts.
From this account we learn that in originating a
nutmeg plantation it is necessary to select ripe and
sound nuts, and set them at the distance of a foot
apart in a rich soil, covering them lightly with mould.
They must then be watered every other day, weeded
occasionally, and shielded from a scorching sun. In
from one to two months the young seedlings may be
expected to appear; and when about 4 feet high,
the healthiest and most luxuriant are to be removed
at the commencement of the rainy season to the
plantation previously cleared and prepared for that
purpose, and set at the distance of 80 feet from
each other, care being taken to protect them from the
heat and from violent winds. The plants are set in
rows, and between these the plough is employed to
clear the intermediate spaces of weeds and grasses,
which in warm climates spring up in great luxuriance
and choke the soil. The plants continue to require
watering every other day in sultry weather; and in
nearly all cases the soil requires to be enriched with
annual supplies of manure, which are laid on during
the rains, and which are made more stimulating as
the tree increases in age. After the fifth year the
trees no longer require to be shielded from the sun;
in the seventh year they begin to bear fruit; and from
that time to the fifteenth year they generally increase
in fruitfulness, being then in their highest per-
fection.
During the progressive growth of the plantation,
the beds of the trees are regularly weeded, and the
roots kept covered with the mould, for these have a
constant tendency to seek the surface: the growth
of lateral branches is alone encouraged, and all suckers
or dead and unproductive branches are removed by
the pruning-knife, so as to thin the trees considerably,
and admit of the descent of the night-dews, which
contribute much to their well-being, especially during
dry and sultry weather. The conclusion of the prin-
cipal harvest is the time chosen for these prunings.
As the trees advance in age, the coarser vegetation
and creepers are alone removed from the intervals
between the trees, and the more harmless grasses are
allowed to remain, giving the plantation a park-like
appearance. The use of the plough is then discon-
tinned.
N utmeg-trees are of two kinds in the same planta-
tion, flower-bearing, and fruit—bearing. The produc-
tive plants are in the proportion of about two-thirds

to the whole plantation. It is impossible to discover
the difference in the sexes of the plants until the
period of flowering. Between the appearance of the
blossom and the ripening of the fruit, a period of
7 months generally elapses ; but when once a tree
has begun hearing, it continues to produce fruit
all the year round, but more plentifully in some
months than in others. The months of September,
October, November and December, are the period of
the great harvest; those of April, May, and June of
the smaller harvest. In the Moluccas these trees
continue prolific for 70 or 80 years; and the annual.
produce, taking one tree with another, amounts to
about five pounds of nutmegs, and a pound and a
quarter of mace for each tree.
When the fruit is ripe, which is indicated by the
bursting open of the fleshy portion, and the appear-
ance of the kernel, it is gathered in by means of long
hooked sticks. The first- step, after removing the
outer integument, is cautiously to strip off the mace,
and flatten it by hand in single layers placed on mats
and dried for 3 or 4 days in the sun. In damp
and rainy weather the heat of a charcoal fire is em-
ployed, but with care that no smoke or heat blacken
the surface of the mace. In drying, the red tint of
the mace changes to orange, its substance becomes
horny and brittle, and its strongly aromatic odour
and taste are preserved. When well cured, it is
made up in tight packages in a dry situation; but is
exposed to the sun about once a fortnight to preserve
its dryness, and thus to keep it from insects which
attack it if it becomes damp.
The nuts being liberated from their macy envelope,
are conveyed to the drying house and placed on a
raised stage or framework, which admits the heat
from a smouldering fire beneath it, to pass freely
among them. The heat is kept below 1400 Eahn,
because too great a heat dries up the kernels, while
too long continued heat produces fermentation, which
increases their volume so greatly as to fill up the
whole cavity of the shell, and thus prevent them
from rattling, which is the criterion of due pre-
paration.
The drying-house'is a brick building of suitable
size, and the stage is placed at an elevation of 10
feet, having 3 divisions in it for the produce of dif-
ferent months. The nuts are turned every second or
third day, that they may all partake equally of the
heat, and such as have undergone the smoking pro-
cess for the period of 2 complete months, and rattle
freely in the shell, are cracked with wooden mallet-s,
and the worm-eaten and shrivelled ones thrown out.
The sound nutmegs are rubbed over with recently
prepared well sifted dry lime, and packed tightly in
chests, the seams of which have been made imper-
vious to air and water. Another and amore common
method is to dip them in a mixture of salt-water
and lime, and then to spread them out for 4 or 5
days in the shade to dry. But the quantity of mois-
ture imbibed during this process, appears to increase
the liability to early decay and to the attacks of
insects. The surest way of preserving the kernel
330‘
NUT—OIL—OOHIKE—QOILS AND- FATS.
would be to export it in the "shell 5 this is done in
sending nutmegs to China; but it does not answer
in Europe, on account of the heavy allowance for
shells, which is one-third of the weight.
The general qualities of the nutmeg and mace are
the same: their agreeable aromatic odour and pun-
gent taste are well known, the peculiar flavour of the
mace, however, being quite distinct from that of the
nut. They contain, according to Bonastre, fat oil
31'6 per cent, volatile oil 60, starch 2d, gum 1'2,
free acid 08, lignine 54. Not more than 41'5 per
cent. of volatile oil is usuallyr obtained in the distilla-
tions at Apothecarie‘s" Hall.‘ The fixed oil, called
flulmeg bulleror eajaressecl oil ofnulmeg, is prepared in
Holland : the nutmegs are beaten into a paste, which
is enclosed in a bag,'steamed and pressed between hot
plates. It is imported in oblong cakes, wrapped in
flag-leaves or leaves of the banana, and weighing
about three quarters of a pound. It is of an orange
or reddish brown colour, and of a fragrant odour. It
is liable to much adulteration, and so also is the
volatile oil, with which turpentine is frequently mixed.
The article called expressed 02] 0f mace is obtained
from the nutmeg, and should bear its name. Nut-
meg butter, according to Playfair, consists of three
fatty substances, two of which are soluble in alcohol,
and the third almost insoluble in that fluid: the third
substance has been termed Myrz'slz'lze, and from this
myrz'slz'e acid is prepared.
Nutmegs are sometimes passed off as fresh, after
the volatile oil has been abstracted from them. Such
nutmegs are very light, and when pierced with a hot
needle, do not give'au oily coating to it. The best
nutmegs are small, but heavy, weighing on an aver-
age 90 grains each. There is a large and inferior
kind "of nutmeg imported, longer and heavier than the
' above, weighing as much as 110 grains. - This is the
produce of another variety, and sometimes of a dis-
tinct species of nutmeg, and is said to be more liable
to produce narcotic symptoms than the true nutmeg.
Nutmegs and mace are decidedly stimulan’gand in 'sm all
quantities wholesome. When used in abundance they
produce, by increasing the circulation, narcotic efiects.
NUT-OIL. ‘The kernels of walnuts-and hazel nuts
yield by expression an oil, which although at first
greenish becomes clear and colourless, —hcnce it is
esteemed by varnishers. It is also -us_ed as the
vehicle for flake-white and other pigments'wherc
the clearness of the colour is required to be preserved.
The warm climate of the South of Europe is favour-
able to the growth of the nuts which yield this oil.
- N-UX VOMIOA. See STRYCHNIA.
‘ OAK-BARK. See TANNING.
' OATS. According to Vogel, oats consist of 66- per
cent. meal, and 3a husk : dried oatmeal consists of

59-00
Bitter matter and sugar s-25
Albuminous matter . 4'30
Fatty oil 2'00
Husk, moisture and loss 23-95
10000
OBJECT-GLASS. See LIGHT.

OBLIQUE ARCH. See RAlLWAY—alld SKEW‘
BRIDGE.
OBSIDIAN, a volcanic glass containing 7 8 per
cent. of silica. It has black and smoky tints, and was
formerly used in Mexico for mirrors, knives and
razors. '
OOHRE, a native mixture of silica and alumina,
coloured by oxide of iron, and sometimes containing
‘a little calcareous matter- and magnesia. The oxide
of iron may occur in so large a proportion that the _
ochre becomes an ore of that metal. [See IRON, page
73.] Ochre is found in beds some feet thick, generally
above the oolite, and covered by sandstone and
quartzose sands more or less ferruginous, and accom-
panied by grey plastic clays of a yellowish or reddish
colour. ' All these substances enter into the com-
position of the ochres. The ochry earths are ground
under edge millstones and elutriated for use: the
yellow ochres may be changed into red or reddish
brown by calcination, whereby the iron is raised to a‘
higher degree of oxidation. Native red ochre is also
called real c/zall and realzlle. See BoLE.
ODOMETER, from 0869, a road, and ,uérpov,
a measure, an instrument for measuring the distances
passed over in travelling. See PEDOMETER.
OILS and FATS. There are two great classes of
oils, the fat, uncluozls or fixed, and the essential or
volatile. The latter have been noticed under Essnn-
TIAL OILS. Oils and fats may be liquid or solid, but
they are easily fusible, and when brought in contact
_with paper they make a greasy mark, and render the
paper translucent. The fixed oils occur both in vege-
tables and animals. In the former they occur chiefly
in the cellular structure of the seeds, and are supposed
by their oxidation or slow combustion to supply the
heat necessary to germination. In animals they are
deposited chiefly in the cellular membrane. The
oils may be of very different consistence even in the
same plant or animal; varying from a thin oil, such
as almond or spermaceti oil, to solid lard or suet. The
vegetable oils are usually obtained from the pre-
viously ground or bruised seed by pressure, in some
cases assisted by heat. In animals the adipose cells,
are broken up on the application of heat by the
liquefaction and expansion of the fat, which runs out
or collects on the surface of the water in which it is
boiled.
The constitution of fats is stated under CANDLE.
to which we must refer. They‘ are compounds of
stem-i0, margerz'e, and olez'e acids, with a base termed
. gZ‘I/eerz'rze, and theater/rule, the vim-recreate and the oleale
of glycerine are respectively term ed slem'z'r‘ze, margarine,
and elaz'rze. Fat- depends for its consistence upon the
proportions in which these substances occur: in the
solid fats stearine or margarine prevails, and in
the liguid oils elaine. The ultimate analysis of fats
and oils reduces them all to carbon, hydrogen and
oxygen. Some of them yield "minute portions of
nitrogen, the result of adhering impurities. The
following table ‘shows-the relative proportions of the
three elements in 100 parts of each of the oils‘
named :-—-_-
OILS AND‘ rrrrs.
P ‘331
_ Carbon Hydrogen Oxygen
Olive 77'21 .... .. 13'36 .... .. 9'43
Almond 77'40 .... .. 11'48 .... .. 10'82
Linseed ....... .. 76'01 .... .. 11'35 .... .. 12-62
,Nnt 79-77 .... .. 10'57 .... .. 9'12 '
_.Cast_or 74'17 .... .. 11'03 .... .. 14-78
Whale .......... .. 76 13 .... .. 12'40 .... .. 11 50
Spermaceti: .... .. 78'91 10'97 .... .. 10'12
Hog’s lard .... .. 79-09 .... .. 11'14 .... .. 9'75
Suet 78 99 .... .. 11'70 .... .. 9'30
Butter 65'60 .... .. 17-60 .... .. 16'80
Fats-and oils are colourless or of a slight yellow
tint: they may- be bleached by prolonged exposure to
light : they are mostly without smell or taste, but
the presence of certain volatile acids imparts peculiar
odours to some of them; thus butter contains hatgrie
and other acids; goat’s fat hireie acid; whaleoil pho-
eeaie- acid, &c., The specific gravity of fats is less
than that of water; but it varies greatly with their
temperature. Thus common hog’s lard at 60°, has a
sp. gr. of 0938: at 122° or in a fluid state, it is
0892; at 152° it is 0881, and at 200° it is 0863.
At 53°. At 75°. At 122°. At 200%.
Nut oil 0'928 0'919 0'871
Almond oil .... .. 0‘920 . . 0'863
Linseed oil .... .. 0'939 0‘930 0'921 0'881
Castor oil 0'970 0'95? 0908
Olive oil .......... .. 0'919 0‘911 0 893 0862
The oils may be raised to a high temperature‘ with- .
out decomposition; but at certain temperatures they
deepen in colour, exhale vapour, and between 500°
and 600° undergo decomposition. Hence they can-
not be distilled in the ordinary way without being.
decomposed. The oils cannot properly be said to
have any toil-tag points, for when they appear to be
in a state of ebullition their glycerine is undergoing‘
decomposition; the fatty acids are either volatilized
or form new volatile products; carburetted hydrogen
and carbonic acid are evolved, and carbon is left behind.
During the distillation the oleic acid is partly con-
verted into sebacic acid, and the stearic into margaric
acid, while the decomposition of the gly cerine produces
an acrid vapour termed aeroteine. These effects vary,
however,_with the nature of the oil. On passing the
:vapour of fats or oils slowly through a red-hot tube
similar efl‘ects'are produced together with a consider-
able quantity' of hydrocarbons in a liquid, vaporous
and gaseous form. Oil-gas is produced by a similar
action as noticed under GAS-LIGHTING. What is
called oil of trial: or philosophefs oil is prepared by
soaking bricks in oil and distilling the oil from them
at a red heat in an iron alembic.
The recently expressed fixed oils are not much
affected by the oxygen of the air: but by continued
exposure to light and air, they absorb oyxgen rapidly,
and give out carbonic acid and hydrogen ;—-this
action may even be so energetic as to produce ignition,
especially where the oil exposes innumerable points to
the action of the oxygen: as when it is absorbed by
porous substances, cotton, tow and cloths used in
lubricating machinery, and then thrown into a corner
in a heap. There can be no doubt that steamboats,
factories, and other places have been set on fire in
this way. What are called drgiag oils, such as nut-
.Tattow oil or oleic acid becomes brown.

oil, poppyseed oil, linseed oil and some others, seem
to undergo this kind of oxidation: when exposed in
thin layers to the air they dry into a kind of resinous
varnish, a process which is greatly accelerated by the
addition of a very small quantity of oxide of lead.
The greasg oils, on the contrary, .do not dry, but
become rancid by a similar exposure.
Chlorine, bromine, and iodine, form acids with the
hydrogen of the fixed oils; on which account chlorine
cannot in general be employed in bleaching the oils.
Chlorine either in a free state or in the state of hy-
pochlorous acid and chlorous acid, may, however, be
used in bleaching some oils; but this method has not
come into general use.‘ Nitric acid, protonitrate of
mercury, and in someeases sulphurous acid, convert
many of the greasy oils into a concrete fatty matter
termed elaidiae. This action does not take place with
the drying oils, and‘ has therefore been proposed as a
means for detecting the adulteration of olive oil with
some of the cheaper oils from seeds, the presence of
which retards the solidifying action; but the test is
not very certain. Sulphuric acid abstracts the gly-
cerine from oils and fats, forming with it salphogtgeerie
acid. The use of sulphuric acid in the preparation
of fats will be noticed further on: and for the action
of alkalies upon fats we refer to Soar. Under. the
influence of heat the oils dissolve small portions of
sulphur, and phosphorus. - :
The purity of the fixed oils may be determined ap-
proximatively, and the. admixture of cheaper *oils
detected, 1, by observing the peculiar odour of the
oil when gently heated by a spirit lamp in a small
porcelain or platinum capsule. The odour evolved
will resemble that of the. plant or animal from
which it was obtained. In this way linseed oil,
whale oil, train oil, or rape oil may be detected even
when used to adulterate another oil. The test, how—
ever, is not always'a safe one, for the odour of cold
drawn oil may difier from the same oil expressed
under: the influence of heat. Olive oil has a different
odour- if grown at different places. 2. By mixing
concentrated sulphuric acid with oil, (1 or 2 parts
acid to100 oil) the temperature rises and the mixture
becomes coloured. If a plate of white glass be placed
on a sheet of white paper, and 10 or 15 drops of oil
be placed on the glass and a small drop of acid added,
a colour will be produced which varies with the oil
employed. With rape oil a greenish blue ring forms
at a certain distance from the acid, while towards the
centre light yellow-brown streaks may be observed.
In traia oil, from the whale or stock-fish, a peculiar
motion begins at the centre and extends to the out-
side: -a red colour appears and becomes more vivid:
in 10 or 15 minutes the margin assumes a violet tinge
which in 2 hours is uniform throughout. Olive oil in-
stantly becomes pale yellow, and afterwards yellowish
green. In linseed oil a beautiful dark brownish red web
is formed, gradually changing into brownish black.
“ It seldom
occurs that a better oil is used to ad ulterate an inferior
one. Oil of almonds, olives, and codfish-oil, will, there-
fore, never be used for adulterating rape'oil, ‘but pro-
332
OILS AND FATS.
bably train or perhaps linseed oil, and sometimes poppy
oil. If we are led, therefore, by the odour to infer an
adulteration,—-for instance by train oil, which occurs
the most frequently—it is only-necessary to place
from 10 to 15 drops of ' rape oil, the. purity of which
is undoubted,‘togetherrwithas? much train§oil, and an
equal quantity of the" oil whose purityis suspected,
and to add to each of thein a small‘drop of sulphuric
acid.“ ‘From the colour produced an inference may
be drawn as to the purity of the oil, and ‘by the dif-
ference of tinges from the .vivid red of the train oil,
and the bluish green of rape oil, the extent of adul-
teration may be‘detected.”1 ' ' '
The, purity of oils may also be tested by'referring-to
theirid‘en'sities, which are said not to ‘vary in 'aii'ap-
preciable manner in the same oil produced in different
years. In Saxony an acror'neter or olepmezfei" is used:
it indicates the specific gravity of oils in such a way
that pure rapeseed oil is indicated by 37° to 38°;
hemp oil by 30° to 31°. There are various other
tests : that by the capillarimeter indicates the quantity
of oil which falls from a certain sized point under
given circumstances. "When oil of almonds or pure
olive oil is shaken in-a phial its surface remains even;
but if mixed with oil of poppies it becomes covered
with small air bubbles. When olive oil is ‘surrounded
with pounded ice it becomes completely solidified,
which is not the case if adulterated with oil of poppies.
Olive oil is sometimes adulterated with honey, which
may be detected by ‘shaking (the oil with hot water,
which dissolves the honey, and the oil separates when
left at rest. The presence of fish oil in vegetable oils
may be detected by passing ‘through them chlorine,
which turns them black._ '
The following is a list of the principal unctuous oils
of commerce:—
. Sp. Gr.
1. Linseed oil—Linum usitatz‘ssimum at peremze. Drying 0-9347
2. Nut oil—C'orylus avellcma, and Juglans regz'd. D .... .. 09260
3. Poppy oil—Papa'ver somniferum. D. 09243
4. Hemp—seed oil-_—_Cannabis satz'va. D.... 09276
5. Oil of sesamum—Scsamum OrientaZe. Greasy............
6. Olive oil—Clea Europea. G. 09176
7. Almond oil—~Amygdgzlus communis. 09180
8. Oil of ben—Guilandina mohrz'nga. G.
9. Cucumber oil—Cucurbz'ta pepo at melapepo. 09231
10. Beech oil—Fagus sylvatica. G. 09225
11. Oil of mustard—rs'inapz's m'gra et aroensz's. G. 09160
12. Oil of sunflower—Helianthus annuus et perenm's. D... 09262
13. Rapeseed oil—Brassz'ca napus et campestris. 09136
14. Castor oil—Ric'inus commmz'z's. D. 09611
15. Tobacco-seed cil—Nz'cotz'ana tabacum at rustica. D.... 09232
16. Plum-kernel'oil—Prunus domestica. G. ................ .. 09127
17. Grape-seed oil—Vitis vinifera. D. 09202
18. Butter of.cacao—The0br0ma 'cacao. 0'8920
19. Coco-nut oil—Cocos nucifcra. G.
20. Palm oil— Cocos but/ymcea, 'vcl avoim elaz's. 0'968
21. .Laurel oil—Lazarus nobil'z's. G.
22.‘ Ground n'ut oil~—-Amchz's hypagoea. G.
23. Piney tallcw—Vateria Indica. G. 9'926
24. Oil‘of Jilliennee-Hesperis matronalis. 09281
25. Oil of Camelina—Myagrum sati'va. D. 0-9252
26.90i1 of weld-seed—Reseda Zuteolm. D. .. . 0'9358
27. ‘Oil of garden-cresses—Lepidz'um sativum. D. c9240
28. Oil ofdeadly nightshade—'Atropa belladonna. 09250
29. Cotton-seed Oil—Gossypium Barbadense. D.
I, (1) This plan is due to Mr. Heidenreich of Strasburg, and is
quoted in full in Dr. N ormandy’s Commercial Hand-Book of
Chemical Analysis, 1850, in which will belfound a large amount
of information respecting the methods of testing the purity of oils.
l
09136
30. Colza oil—Brassz'ca campest-rz's olez'fe‘ra. G.
31. Summer rapeseed oil—Brassicaprwcow. G. 09139
32. Oil of radish-seed—Raphanus satz'vua olez'fera. G. 09187
33. Cherry-stone oil—Przmus cerastus. G. 09239
34. Apple-seed oil—Pyrus malus.
35. Spindle-tree oil—Euonymus Europwus. G. 0'9380
_ 36. Cornel-berry-tree oil—Camus sanguinea. G.
37. Oil of the roots of cyper-grass—C'yperus esculcnta. G. 09180
138. Henbane-seed oil—Hyoscz'amus ‘nlz'ger; . 09130
39. Horse-chestnut Oil—ESCUZUS hipjvocastanum. G. 0'927
40.~Pine-top oil—Pinus abz'es. D. . 09285
The proportion of oil contained in seeds is often
very, considerable: linseed contains 20 per cent. of
oil; ‘rape-seed from; 351‘to ~40§rcaston oil seeds as
much as 60 per cent.~'T-__Tlie oil is usually obtained
by means of expressionz. An oilimill is used for
the purpose‘; but it is desirable ‘first to pass such
hard seed as lint or rape between iron rollers, in order
to crack the shells. These rollers are of cast-iron,
turned truly in a lathe, and their spindles run in brass
bushes fixed in an iron frame bolted to the framework
of the mill. These frames have mortises, in which
the bushes for the rollers are placed and are adjusted
by screws passing through the ends of the iron frames :
this’ allows. the rollers to be set at any distance apart,
accordingto the size and hardness of. the seed to be
crushed. The rollers are sometimes of different sizes,
so that different velocities may be given to their sur-
faces : this enables them .to draw the seeds in, and to
perform their ‘work more quickly. One of the rollers
has on its axis a small spur-wheel, which engages a
cog-wheel on the main shaft of the mill. It conveys
its motion by another pinion to the second roller. By
giving to the roller pinions a dissimilar number of
teeth, they may be made to revolve with different
velocities, which answers the same purpose as making
them of different sizes. Above the rollers is a hopper
containing the seed, which runs out at an opening in
the bottom into a trough or shoe, which is agitated
by a piece of wood nailed to it resting on the cog-
wheel: the shoe thus ‘feeds the rollers with a small
quantity of seed at a time, and prevents them from
being choked up. A plate of iron attached to the
frame on each side presses by its edge against the
lower part of the rollers, and scrapes off any adhering
seed._ The crushed seedifallsxupon an inclined board,
and collects in a heap,.from which it is removed to
feed the running stones. The arrangement of the
rollers resembles that of. the crushing—mill described
under METALLURGY. , v .
The seed broken by the rollers is passed under two
vertical mill-stones or- runners, revolving on a hori-
zontal bed, where it ‘is further bruised and prepared
for compression. In some places the rollers are not
used, but the seed is at once subjected to the action
of. the runners. Hard and smooth grains are, how-‘
ever, liable to slip away from beneath the ‘running;
stones, and thus require amuch longer time to prepare
them for the next process, that of compression.
Rollers do their work rapidly, but they require great
power to work them. When the seed is sufficiently
bruised ‘by either or both of these means,'it is collected
into hair bags and placed in what is called a wedge-press.
In ‘olive-oil mills a screw-press may be used 5 but the






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'f
OILS AND FATS.
333
hardness and smoothness of the grains of lint and rape,
and the cavities formed by the broken shells which
retain the oil, require the exertion of a stronger force.
The hair bags containing the crushed seeds are placed
between wedges of wood contained within a strong
framing. The wedges are then driven down by a
heavy ram or pestle worked by machinery until the
pestle rebounds from them 3 times, when they are
judged to be sufficiently tight. The oil_ thus ob-
tained is of the best quality, and is kept distinct
from that obtained by the after processes. The seeds
come out of the bags in the form of flat cakes: these
are broken up, and pounded in mortars with heavy
Stampers, which reduce the parenchyma of the seed
to a fine meal, so that the oil can escape more freely
when subjected to a second compression, which is now
aided by heat. The pounded seed or meal is heated
to the temperature of melting bees’-wax in a pan, and
is kept in agitation by a spatula worked by machinery.
The meal is again put into hair bags and compressed,
and the resulting oil is considered to be the best of
the second quality. Another compression produces
oil of the ordinary second quality. During the heating
of the meal a little water is sometimes added; but in
Holland this practice is considered to be injurious.
The cakes are still fat and soft, and are sold as food
for cattle ; but the Dutch break them down and stamp
them again. The result is an impalpable paste, which
is heated with a very little water, and kept for some
time at the temperature of boiling water, with diligent
stirring. It is then subjected to the greatest pressure
that has yet been applied, and the result is an oil of
the lowest quality. The cake is dry and hard like a
board, and is used for manure. Some of the small
millers in Holland purchase oil-cakes from France
and Flanders for the purpose of preparing this in-
ferior oil.
Our steel engraving represents an oil mill used for
grinding and pressing linseed, rape seed, and other
oily grains: W, Fig. 1, is a spur-wheel, which may
be worked by water-power, steam, wind, or other con-
venient means. It engages the wheel w’, which is
attached to, and gives motion to the horizontal tum-
bling shaft ss. This shaft carries round its circum-
ference wipers for lifting the pestles, so arranged
that each pestle may be raised twice during one
revolution of the shaft. The wipers consist of a
square socket, Fig. 2, fitted on the shaft with arms
furnished with rollers w’ at their extremities, which
produce less friction and wear than rubbing surfaces.
The framework Fr which supports the pestles con-
sists of 41 strong uprights, with rails bolted firmly
to them across, and to which small transverse pieces
'are attached for guiding the motion of the pestles.
When not at work, the pestles are raised up by the
levers jw engaging the projection 12, 2, on the
side of the lifter, so that the lifts are clear of the
wipers: the levers turn upon a joint at j, and by
releasing the rope '1', the pestles are left free to
work. The press boxes BB, Fig. 1, in which the
grain is squeezed after it has left the running stones,
Figs. 42 and 5, and the 6 mortars gum, Fig. 1, are con-

tained in a strong block of stone or timber't t. The
mortars are generally hollowed out of the block itself,
and a board is placed on each side of the mortars
inclined so as to form a trough which prevents the
seed from being scattered by the fall of the pestles.
The large press box 18, Figs. 1 and 3, is also hollowed
out of the block, or framed with sufficient strength
to resist the enormous pressure of the wedges. This
first box is used for pressing the grain as soon as it
comes from the stones, and the second press-box B’
is used for squeezing the grain after it has been
pounded by the pestles. The bags of seed 66 are
placed between iron plates, which are united at bottom
after the manner of abook cover: the bag is shut up
between them, and there are small holes in the bottom
of the press, from which the oil oozes out into vessels
placed to receive it: w w are the driving wedges, and
z' z' the dischargers or inverted wedges for relieving
the pressure. The rest of the press is filled up with
blocks of wood, which rest firmly on the bottom to
prevent them from being carried down by the wedges,
and thin pieces of wood are placed between them and
the wedges to make them slide more easily by each
other. it n are the drivers which strike the wedges,
and n’ n’ the stampers which strike the dischargers
or relieving wedges. These rams are moved by
wipers on the horizontal shaft, and their action will
be better seen in Fig. 2, in which s is a section of the
tumbling shaft, with the 2 wipers w" attached to it ~;
the roller at the end of each wiper engages the lift
or projecting piece 0 e on the pestle It, and raises it
to a certain height, when, being relieved by the re-
volution of the shaft, the pestle falls with its whole
weight in the mortar: it is again raised by the next
wiper, two blows being given for every revolution of
the shaft. It will be seen that the action is precisely
similar to that of the stamp-mill described under
Mn'rALLUneY. The pan for heating the grain is
shown at 72, Fig. 2 : it is a small circular copper pan,
heated by a fire beneath: the spatula s, for stirring
up the grain and preventing it from sticking to the
bottom and sides and becoming overheated, is attached
to the lower end of a vertical spindle o, the revolution
of which causes the spatula to turn round in the
grain. The spindle derives its motion from a hori-
zontal shaft, furnished with a wheel at one extremity,
by which it is moved by the main shaft, and a similar
wheel, at the other extremity, allows it to engage'the
wheel at the top of the spindle by lowering the hori~
zontal lever Z. In its present position, the lever acting
on a shoulder projecting from the spindle holds the
latter out of gear. In front of the chauffer pan is a
basket tapering downwards so as to form a narrow slit
at the bottom. The hair bags are put into this basket
and filled with the warmed grain, which is taken out
of the chauffer with a ladle.
The plan now becoming comm on of heating the
grain by means of steam is preferable to the above.
A steam pan is shown in section, Fig. 1526. The
grain is put into I’, steam is admitted into the jacket
by the pipe 8, and the condensed water is let off by w.
The form of stirrer is shown in Fig. 1527 5 and a
334
OILS AND FATS.
. or lower millstone.
plan of the pan with the stirrer is given in the steel-
engraving, Fig. 7.




The running stones are shown in the engraving,
Figs. 4 and 5. They revolve in a strong frame-work
attached to a vertical axis, which also slowly revolves
by means of a large cog-wheel at the top, which en-
gages awheel upon the main shaft s. The stones have
thus a double motion, one on their own axis, and the
other, by which they are carried round upon the bed
A is the vertical axis, and A’ A’
the horizontal axis of the stones : this axis passes
through the vertical axis, and has its bearing in the
frame-work. The holes in the millstones are made
rather wide, and those in the frame are vertically oval
(see Fig. 5), in order to give greater freedom of motion,
and to allow the stones to pass over any heaps of grain
without straining. The bed-stone is supported on
a strong foundation of masonry, and is surrounded by
a raised border to retain the grain. In the centre is
a block of wood carrying a brass bush, in which the
vertical shaft turns. The grain is collected under the
stones by means of rakes or sweeps attached to the
framework, and revolving on the surface of the bed-
stone, so that the grain which is spread and dispersed


Fig. 1527.
Fig. 1526.
'by the motion of the stones is collected into a ridge
in the line of motion. The inner rake collects the
grain under the outer runner, and the outer rake
under the inner runner. The'outer rake is also pro-
vided with a rag of cloth, which rubs against the
raised border or hoop to collect any grains that might
be attached to it. One of the runners is set about
2-thirds of its own thickness nearer the shaft than the
other, so that the stones having different treads ope-
rate over a larger extent of surface. The inner rake
gathers up the grain under the outer stone in a ridge
shape, and the stone passes over it and flattens it,
when the outer rake again gathers it up into a ridge.
~The outer rake consists of 2 parts, the outer of which
{presses close on the wooden hoop and pushes the seed
obliquely inwards, while the inner part of the rake
gathers up the grain which has spread towards the
(centre. The other rake has a joint near the middle
of its length, by which the outer half of it can be
raised from the nether stone, while the inner half con-
tinues to press upon it and scrape off the moist
paste. Figs. 5 and 6 will show the form of these
rakes, ‘and the method of mounting them. When
the seed is ‘properly bruised, the man lets down
the outer end’ of the rake, which gathers up the
paste, and sweeps it obliquely outwards to the wooden
rim, where it is brought to an open part of the
vhoop, and it ‘falls ‘out into troughs placed for its,
which requires a much longer time.

reception. These troughs are perforated at bottom,
and a quantity of oil oozes out, and is conducted into
a cistern apart: it is considered to be very pure, as it
is obtained by the breaking of the shell and not by
expression, which may be supposed to introduce
mucilage and other matters into the oil.
In the oil cisterns the parenchymous part of the
seed gradually subsides, and the liquor in the various
divisions or cisterns consists of oil of different degrees
of purity. The pumps which raise it from the cisterns
are in pairs: one pump lifts it up from the very bot-
tom, and the other from half the depth. The last
only is barrelled for the market: the other half is put
into a deep and narrow cistern, where the dregs again
subside, and more clear oil is obtained. A press will
crush '7 cwt. of seed per day in the first operation,
when the grain comes immediately from the rollers;
but only 2 or 212- cwt. per day in the second pressing,
A quarter of
linseed produces on an average from 15 to 18 gals.
of oil.
The action of sulphuric acid upon fatty substances
has been already referred to as laying the foundation
of a considerable branch of industry, by which the
most foetid and impure fats and oils can be completely
purified, and converted into pure stearine adapted to
the manufacture of candles.1 Sulphuric acid exerts
upon fats an action somewhat similar to that of the
alkalies; with which the fatty acids unite, and the
glycerine is set free: but in the case of sulphuric
acid there is this difference; the acid combines at
first with the whole of the fatty substance, and the
glycerine is afterwards isolated under the action of
water in the formof sulphoglyceric acid: double acids
are then formed with each of the other fatty acids,
forming sulp/zoleic, sulplzomargm'z'c, and sulp/zosz‘earz'c
acids, the first of which is soluble in cold water,
while the two others'are decomposed by it: all three
are decomposed by boiling water, which forms a solu-
tion with the sulphuric acid and the glycerine, and
leaves the fatty acids floating on the surface.
The fatty substances employed in what the French
chemists term the sulphuric saporzzficaz‘z'orz, are the
most inferior greases and refuse that are sent into the
market. In France the sources of supply are, 1, the
soapy waters obtained by washing woollen cloth after
the process of fulling; 2, bone fat, obtained by boiling
down bones, 3, the miscellaneous collection which in
England is known as kitchen-852%’; 4, the refuse
matters of olive and other oil-mills ; 5, the scrap-
ings of the cat-gut manufacturer ;. 6, refuse of cod-
liver oil, whale oil, 850.; '7, residue of soap works,
&c. &c.
In the treatment of the soapy waters, which contain
a mixture of olive oil or oleic acid and soap, sulphu-
ric acid is added, which, combining with the alkali

(1) A11 interesting Paper on the Stearic Candle Manufacture
was read before the Society of Arts on the 5th Feb. 1852, by G. F.
Wilson, Esq‘, Manalging Director of Price’s Patent Candle Com-
pany. This paper has been printed for the use of the Members.
The Jury Report, Class XXIX, also contains a historical notice
of this important manufacture, with short accounts of ‘the lime
process and the acid saponification. : a ' ~ ~ - ~-
OILS AND FATS.
*335
present, causes the fatty matters to separate and rise
to the surface. The fat is removed by means of flat
colanders to a water-bath, where it is fused at a very
moderate heat: the fluid oil is decanted off, and the
solid deposit is put into woollen bags and subjected
to pressure under the influence of heat 5 by which the
fluid acid is separated from the solid.
Should the fatty substance be contaminated with
dirt, clay, W001, 800., it is put into bags, and cold-
pressed in order to separate water. It is next pressed
in a cast-iron box heated by steam, by which means
the fluid oil is separated. It is next fused in awater
bath: the purer fluid portion is decanted, the solid
portion is subjected to the chemical processes about
to be described, while the muddyr residue is made to
give up its remaining 'fat by the action of boiling
water and another pressure, and what is left is em-
ployed as manure.
The first washing of the fatty substances by means
of sulphuric acid is conducted in large wooden tubs
lined with lead, and heated by steam discharged into
them by a perforated pipe. The agitation is kept up
for from 15 to 30 minutes, and after reposing for a
similar length of time, the water is drawn off by
a pipe at the bottom into a vessel similar to Fig. 1529,
in which the fatty matters carried off by the water
are retained. The fat which has been thus washed is
put into a vessel heated by means of a steam-jacket,
and the water is driven off by evaporation. The fat
is then ready to be treated with strong sulphuric acid,
an operation which is carried on in a boiler of copper
or iron B, Fig. 1528, furnished with a steam-jacket.
Above the boiler is a chamber H for collecting the
fumes of sulphur-
ous acid, fatty
acids, acroleine,
&c. : these are
drawn off by means
of a pipe v pro-
ceeding from the
chamber to the
ash-pit of the fur-
nace fire, where
they are got rid of
by being passed
through the fire,
thus preventing a
prolific source of
nuisance, not only to the factory, but also to the
neighbourhood The fatty matters are kept in a con—
stant- state of agitation with the sulphuric acid by
means of a mechanical stirrer s 8’ moved by a crank
c which acts similar to the beater of such a churn
as is represented in Fig. 389, article BUTTER. This
prevents the heavy matters from subsiding. The
proportion of sulphuric acid employed varies with the
kind of fat: mixed fats require from 10 to 13 parts
of concentrated acid for every 100 parts of fat: palm
oil, 8 or 9 per cent. of acid, while certain solid fats
take from 12 to 16 per cent. These proportions are
ascertained beforehand by experiment. The tem-
'dwl.~~
.Fz'g. 1528.

24100 Fahrl, and the operation lasts from 12 to 18
hours. Specimens of the liquid are taken out from
time to time and poured into an evaporating dish : the
kind of consistence acquired in cooling, and the dis-
appearance of the violet tint, shows how the opera-
tion is going on, and whether it is near completion.
When the fat is properly converted it is left to cool
for 2 or 3 hours, after which the liquid is drawn oft’









S; i
L]
~,-_,=;:,::=v~:~. tiling“; "I - -_n- r
w. ~— %1 m *2:
._-_-_~ ___.,> .
I._- : =5’Ea M ='‘ 952:1?
_'-———-___ Mfg .'-‘
' ._s g?
11- - . - ‘ \_, -—7=-0 ' n ’ ‘
é/‘I "fig-J l o - ‘-
1 M.
m \ “m““\\‘_&\fimwm
\‘\
“t M a.._\\\\\'\\\\\\\\
Fig. 1529.
by a syphon a‘, Fig. 1529, into a cistern v, which con—
tains one-third of water: steam is now injected into it
from the steam-pipe SI’ by means of the perforated
branch .9. The water, thus raised to the temperature of
212°, efliects the decomposition of the sulpho-fatty
acids: the fatty acids float on the surface, and they
are washed by means of boiling water conducted by
the pipe 5, by which they were conveyed into the vat.
The water, holding in solution sulphoglycerie acid,
and several foreign matters, passes under the dia-
phragm (Z of the first vat, and flows into the second vat
v’: steam is injected into it by means of the pipe 8’,
furnished with a stop-cock for regulating the supply:
the temperature is thus raised to 212°: the larger
portion of the acids which had been dragged over by
the water rises to the'surface, while the watery solu-
tion, passing under the diaphragm cl’, enters the third
vat v”, where similar effects are produced. The aque-
ous portion passes under the diaphragm d”, and it is
directed by an overflow-pipe T into a series of 3 or 41
other vats similarly arranged, but formed of masonry
or of compact bricks cemented by bituminous mastic.
During the acid saponification and the washings,
the fusing point becomes raised, as for example :—
After the action After washing.
Fuses at of the acid at at 212°, at
Bone fat and stuff... 75° 97° 100'4°
Palm oil 86 100.4 111
The fatty acids having. been purified by washing in
the first vat v, are drawn off by a stop-cock a placed
above the level of the water, into a vat which feeds
the distillatory apparatus. The fatty matters floating
in the vats v’ v", are skimmed off, and transferred to
the first vat v, where they are washed with the
products of a second acid saponiflcation. After
each saponiflcation, there remains at the bottom of
the boiler a black bituminous substance, forming
from 4! to 10 per cent. of the stufl originally em-
ployed. This substance after having been washed
with boiling water, might be used in the manufacture
of gas for the purposes of illumination. The vat in
which the purified fatty matter is collected, is warmed
by a jacket, in which circulates the water from the
condensed steam on its way to the boiler cistern.
perature of the mixture maintained at 230° to I This keeps the vat at a temperature of from 1000 to
336
OILS AND FATS.
120°, at which moderate heat some foreign ‘matters
and water mechanically mixed, become deposited.
The fatty matter is decanted into a flat boiler r, Fig.
1530, which is furnished with a dome-shaped cover,
-so that the water which condenses on its under sur-
face may trickle down into a gutter, which forms a
water lute to the vessel, and from this gutter it
escapes by an overflow-pipe. In this boiler the fat
gets rid of water, and it is raised to the required
temperature by the waste heat of the furnace below,
Fig. 1530.
containing hot cinders, which keep up the tempe-
rature. The liquid fat is introduced into B by means
of the pipe go, the flow being regulated by the stop-
cock. When the liquid fat has reached 480°, the
high-pressure steam is admitted, a thermometer let into
the pipe near 0, indicating its temperature, which is
kept at from 480° to 580°. At such a heat, and
under the influence of the steam, the last portions of
the neutral fatty matters are transformed into fatty
acids and glycerine, the former of which are carried
away in the current of steam along the pipe l,‘ into
the vessel (l, and from thence by the tube 5' into the
double worm. The vessel cl allows of the separa-
tion of the first portions of the distillation, which
contain sulphuric acid, acroleine, &c. The fatty and
aqueous vapours are condensed in the‘ worm, and
the liquids flow by the tube 19' into a Florentine
receiver r. The lighter fatty acids remain in the first
division, and can be drawn off by the stop-cock j,
while the aqueous portion passing below the dia-
phragm can be discharged by w.
The fatty acids which are successively volatilized
in B, vary in composition with the time occupied from
the commencement of the operation, and the nature
of the crude material, so that the condensed products
have different fusing points, as for example :—
Grcen fats and
bone fats. Palm oil’
1st product 104° 130°
26. ,, 106 125-5
3d ,, 106 1185
4th ,, 108 1 15
5th , , 111 111
6th , 113 1 06
7th , 106 102'5


escaping into the fines. This furnace is used for
heating the tubes 8 s, which are filled with steam
by the cock 86, which communicates with a boiler.
The steam in the tubes 8 s, is raised to the tempera-
ture of about 57 0°, and on opening the stop-cock c,
it is admitted into the boiler B by the perforated
tube and rose-head r. The boiler B is of copper,
with a domed cover D, in which is a man-hole. Heat
is applied to the boiler by means of a sand-pot s s,
and the whole is surmounted by a hollow cover 0,
APPARATUS FOR THE DISTILLATION OF FATTY ACIDS.

In the course of 12 or 15 hours, from 18 to 22 cwt.
of fat may be distilled in the alembic B, which is
about 5 feet in diameter, and 6 feet high. There
remains in the boiler a brown fluid residue, which is
removed by means of a syringe s, which passes up
into the boiler. This fluid acquires, on cooling, the
consistence of asphaltum or bitumen: it amounts to
6 or 7 per cent. of the matter produced from green
fats and bone fats, and 4.1 or 5 per cent. of the weight
of palm oil. No use has hitherto been found for this
substance, but it might probably be employed in the
manufacture of blacking, of black sealing—wax, of a
black varnish for leather, or even of a common kind
of soap. Indeed there are many waste products which
might be converted into soaps with great advantage
to the manufacturer, and still greater to the con-
sumer, did not the unwise regulations of our excise
interfere.
By a modification of the apparatus just described,
the operation is made continuous. It consists of a
cylinder 0, Fig. 1531, surrounded by a vessel L, con-
taining molten lead, which communicates the amount
of heat required. A man-hole above 0, usually kept
closed, gives access to the cylinder for repairs, &c. The
acidified fat, washed and dried, as already explained, is
poured into the cylinder in a small stream by means of
the funnel j, the stem of a float within the cylinder
cutting 05 the Supply when it has reached a certain
height. The mixture of fatty acids in the cylinder
being kept at a temperature approaching 600° by
means of the lead bath, steam is injected into the
cylinder. The steam is conveyed from the boiler by
means of the tube sp. It first passes into the vessel
OILS AND FATS.
337
20, where any particles of water, which ‘may be en-
tangled with it, are either deposited or vaporized.
f2)‘:


Fig. 1531.
The steam then passes into the cylinder by the tube
88, the horizontal part of which, placed near the
bottom of the apparatus,
is pierced with a multi-
tude of holes, andthus the
steam flows up through
the mixture of fatty
acids, the vapours of
which are carried by the
steam along the pipe 1)
into the refrigerator. At
the end of every 3 or 41
days, the black carbona-
ceous accumulation in the cylinder must be drawn
ofl‘, as in the former case.
The fatty products of the distillation are received
into large crystallizing pans of cast-iron, lined with
enamel, and they are further purified
by pressure, either at ordinary tem-
peratures, or under the influence of
heat. In the distillation of palm-oil,
the last products may be treated in
a similar manner 5 but the first por-
tions, which fuse at from 115° to
130°, can be moulded pinto candles
without further preparation. The
white cakes of the second hot-press- 51
ing of the distilled products of mixed
fats, are melted in vats heated within
by means of a coil of pipe, through
which steam circulates. Here they .~ ~
are clarified by means of hot water
containing alittle oxalic or sulphuric
acid, and this terminates the process.
The percentage of solid fatty acids
obtained from refuse and other fats
and oils by the above processes, varies considerably
with the nature and source of the material: for while
palm oil will yield from 70 to 80 per cent. of solid
available matter, the waste oleic acid of the stearine
factories will only give from 25 to 30 per cent. The
fat produced-by boiling garbage, &c., 60 to 66 per
cent., waste olive oil 55 to 66, and so on.
The hydrostatic press is used for pressing out
the oleic from the solid acids, as explained in our
article CANDLE. In hot'pressing, the distribution of
the heat uniformly has been a difficulty. The presses
VOL. II.


Fig. 1532.
‘4021"
‘- -’ ' 1a’;- 4 -
JOQQAQ-QQi-Qloxa'
"-
¢ . -





\xms\\\\n\\\\\\\\\\\\\\\\\\\\\\
%W\\.\w

have been arranged both vertically and horizontally,
the latter position being more convenient. The bags
containing the fatty matter are placed between cast-
iron plates, having a serpentine
hollow or channel through the
middle of their thickness, as shown
-‘
\\
\
\\ \\

\\
in Fig. 1533, for the passage of \\ \
steam, and thus they can be raised
to the desired temperature; the -
steam is supplied to them by tubes ‘
furnished with articulated joints, \\\\
so as to follow the motion of the \m
press. TlllS arrangement Wlll be ‘er—4",“?
better understood by referring to
Figs. 1535, 1536, in which s 'r is
the steam-tube communicating with the boiler; on
opening the cock at e, steam enters all the tubes .9 ts'j,
and passes down the channels in
Fig. 1533.




the iron plates 2'10, shown more distinctly in Fig. 1534:. Joints at s j allow of the motion of the boxes, and a stuffing at z‘, where the thinner tube enters the thicker one, allows the tube st to play steam-tight in z‘ s’. ‘Fig. 1534. represents two plates with the horse-hair or matting-bag between ‘la—£5
Fig. 1534.’
them containing the fat, which
has already been 00ld~presscdz B, Fig. 1535, is
the ram of the hydrostatic press, and w the tube
which conveys water from the force-pump ; v is a
safety-valve.
The fluid oil expressed from the solid


. \.\j s\\\s
\\\\\\\\\\\\\\\\\\\\\\\\‘\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\
‘~‘\\\\\\Q\YK\\\\\Y‘

Fig. 1535.
Fig. 1536.
acids is received into a channel g, which conveys it
to a vat o. It may be used as a common oil for
lamps, or for the preparation of soaps.
We conclude this notice of the sulphuric sapouifi-
cation, with an abstract of the process as conducted
at the works of Price’s Patent Candle Company, and
described in the Jury Report, Class XXIX. See also
CANDLE.
About 20 tons of fat, say palm oil, are fused by a
steam-jet in a lead-lined vat. The fluid mass having
settled, is pumped up into the acidifying vessel, and‘
z
338
OLIBANUM—OLIVE OIL.
heated to 350° by a steam-jet. Concentrated sul-
phuric acid in the proportion of 6 lbs. for 112 lbs. of
oil is used, and under the influence of the acid and
the steam the oil is decomposed, and much blackened.
The fat is drawn off into the washing tub, and boiled
up with water by means of a steam-jet. After one or
two washings the blackened fat is pumped up to the
supply tank, which commands the stills. These are
of copper, heated by an open grate, each still capable
of holding 5 tons of fat. The temperature is raised
to 560°, and steam is passed through the mass. The
steam and fatty acids distil over into a series of
vertical pipes of the temperature of 212°, where the
fats only condense while the steam passes to a second
refrigerator cooled by a current of water. Here it is
condensed together with the minute portion of fat
carried over, which floats on the surface, and is
recovered while the water flows off at bottom. After
the distillation has been continued for some time, the
residue in the still is transferred to another still,
formed of iron pipes set in a furnace, and there sub-
mitted to a higher degree of heat, and to the action
of more highly heated steam. An additional quantity
of fatty acids is thus obtained. The residue left is a
sort of pitch, and may be used as such. The fatty
acids as they run from the still are used without press-
ing in the manufacture of Composite candles: they are
self snufiing, but more fusible and soft than the
pressed stearic acid candles. A better sort of candle
is made from the pressed acid, 50 hydraulic presses
being used for the purpose. In cold pressing, the
fats are spread on woven mats, and pressed between
iron plates: the oleic or metoleic acid which runs out
is sent to Germany to be made into soap. The fat
acids are next hot-pressed in hydraulic presses con—
fined in a chamber heated by steam. The pressed
cakes are melted in contact with a little dilute
sulphuric acid, ‘and run into blocks which are used for
making candles. [See CANDLE] Pressed coco-nut oil
is largely employed to mix with the pressed acids of
palm oil for the best composite candles.‘
OIL COLOURS. See PAINTING.
OIL GAS. See GAS-LIGHTING.
OLEIC ACID. See CANDLE—Orbs and FATS.
OLIBANUM. A fragrant gum-resin which consti-
tuted the frankincense of the ancients, and which also
possesses stimulant, astringent, and diaphoretic pro-
perties. The tree which produces it is the Boswellz'a
sermm, which grows freely among the mountains of
Central India, as well as among those of the Coro—
mandel coast. It forms one of a group of trees ex-
clusively natives of tropical India, Africa, andAmerica,
and yielding myrrh and frankincense with an abun-
dance of fragrant resinous juice.

(1) Among the authorities referred to in the preparation of this
article we may mention Dumas, Chimie Appliquée, tome v.;
Payen, Chimie Industrielle; the volume on Arts and Manufactures
in the Encyclopaedia Metropolitana; and two volumes in the
Encyclopedic Roret, entitled, “ Manuel du. Fabricant et de
l‘Epurateur d’Huiles,” par M. Julia de Fontenelle, 1836; and
“ Manuel complet de la Fabrication des Acides Gras concrets et de
celle des Bougies Stéariques,” 858.. Par M. F. Malepyre. Paris,
1849.

Olibanum is imported from India in round, oblong,
or ovate tears, of a pale yellow colour, partially opaque,
and having a balsamic odour. According to Johnston,
lumps of this substance, which only appear to differ
slightly in colour, behave differently when treated
with alcohol; some become quite transparent, others
white and opaque, from a powdery coating left on the
surface. The latter contain an acid resin : C4 0113206,
constituting the larger portion of the olibanum of
commerce, and associated with a variable quantity of
volatile oil. The clearer and yellower pieces give
less gum than the others, and contain a resin repre-
sented by Clio H32 04 and resembling colophony. It is
uncertain whether the substance known as Arabian
frankincense is the produce of an Arabian tree of the
genus above described. The affinity in vegetation
between parts of India, Persia, and Arabia, would
lead to the supposition that it is so, but on the other
hand, many fragrant substances once supposed to be
the produce of Arabia, are now found to have been
first obtained from India or Africa, and then re-
exported.
OLIVE OIL. Vegetable oils are in most cases
extracted from the seeds of plants, but in the case of
the olive, the best oil is contained in the pulpy part
of the fruit, and this is carefully extracted before the
seeds are subjected to pressure. The olive is a tree
which grows luxuriantly in Italy, whence our chief
supply of the oil is obtained; but it is not indigenous
to that country, having been transmitted thither from
its home in the east. Asia, the birthplace of civiliza-
tion, was likewise the birthplace of the olive; and in
the western world the tree followed the progress of
peace, of which it is considered the symbol. The
olives in Syria and the Holy Land are very numerous
and of great age, springing up without culture in
wild luxuriance. The olive-groves of Greece are
likewise famed, and some of the Greek islands export
large quantities of the oil. Olive oil is also to be
obtained on the African coast, and in the south of
France and Spain.
The olive-tree is not very much unlike the English
willow, and is frequently pollarded in a s'milar
mamier. The scenery in that part of Italy which
may be called “ the heel of the boot,” is rendered
monotonous by the immense olive-groves which cover
the country. Throughout the whole of the two pro-
vinces Bari and Lecce, or La Terra d’ Otranto,
scarcely anything else is cultivated. The most cele-
brated port of these provinces is Gallipoli, which
gives its name to the oil brought from an extensive
district. Great part of the merit of Gallipoli oil
arises from the facilities which that town possesses
for keeping it pure and fresh after it is brought in
from the country. These will be noticed presently,
but we must first describe the very simple means
employed to procure the oil.
Olive—trees begin to hear at two years old, but are
not in full bearing until after five or six years, when
they become a sure source of wealth to their owners.
They are of extreme longevity, and will bear luxuriant
crops when, the trunk is quite hollow. A tree of this
~ OLIVE OIL.
339
description, whose empty shell scarcely supported it
against the mountain storms, is stated to have pro-
duced in one year 240 English quarts of oil. Some
years ago there was an olive-tree near Nice in a
decaying state, which-had been the wonder of that
part of the country on account of its enormous size and
great age. The lowest extremity of the trunk measured
38 feet, and one of the main branches 6% feet in cir-
cumference. As far back as 1516 this tree was dis-
tinctly recorded as the oldest in the neighbourhood.
In former years it has borne upwards of three hundred
weight of oil in one season, and so late as 1818 it
produced two hundredweight. A celebrated olive~
tree at Pescio was said to be 700 years old. These,
however, are exceptional cases, and it appears probable
that the majority of trees do not continue productive
much above a century, unless great attention is
bestowed upon them.
The ingathering of the olives is performed in dif-
ferent ways. Some cultivators allow the fruit to
attain complete ripeness and to drop from the trees.
Others consider that the fully ripe fruit produces too
fat an oil, and one which is liable to become rancid;
they therefore gather it a little before it is ready to
drop. Others again prefer gathering the fruit some
little time before it is ripe, but the oil thus obtained
is liable to be sharp or bitter. The fruit is sometimes
beaten off with poles, ‘a very injurious plan for the
trees.’ The olives likewise are bruised, and unless
used directly, the oil obtained from them has a bad
flavour- The more tedious process of hand-gathering
is therefore to be greatly ‘preferred. In order to
obtain the finest description of oil, the ripe fruit is
conveyed at once to the mill, or if unripe, it is allowed
to lie for 241 or 418 hours in a dry place until it
begins to wrinkle. For inferior oils or for soap, the
olives are heaped up in storehouses, sometimes for
months together, and lose much oil from fermentation,
while that which remains is greatly deteriorated in
flavour.‘ With proper precautions, however, such as
frequent turning of- the heaps, leaving spaces for the
air to circulate, and keeping the several gatherings
distinctfmuch of this loss may be avoided.
The crushing of the olives is effected in a mill of
the simplest construction, consisting sometimes of
a single mill-stone, turning in a circular bed: at
others, of two mill—stones, placed far enough apart
not to crush the seeds. The workmen remove the
pulp when sufliciently crushed, and place it in bags
or sacks, which are heaped up on the platform of
a press. This is also of a very rude description, and
gives but a slow and feeble pressure. The oil which
first exudes from the olives (supposing them to be
of good quality) is a fine pure oil, much sought after
for the supply of the table. It is known in commerce
as virgin salad 02]. After this is all extracted, there-
yet remains a considerable quantity so mixed with
vegetable albumen that it cannot flow out. The bags
of pulp are therefore lifted up, and between each is
poured a certain quantity of boiling water. This
causes the- pulp to swell by the absorption‘ of the
water.- the albumen coagulates, and the more-fluid

oil flows freely. Still a certain quantity of ‘oil
remains among the refuse, and this is subjected to
further treatment in separate workshops, the resulting
oil being only fit for soap-making. The imperfection.
of the former processes alone renders these latter ones
necessary, so that a large amount of time and labour
is thus unnecessarily expended.
As soon as the first run of fine oil is obtained from.
the olives, it is conveyed in jars or skins to a reservoir,
and on the nature of this reservoir much of its after
value depends. The town and port of Gallipoli owe
much of their celebrity to the circumstance of the
former being built on a rocky island, easily excavated
into caverns and cisterns‘ where the oil soon clarifies,
and can be long preserved without becoming rancid.
A Gallipolitan oil-house is described as being the
ground-floor of a dwelling-house, in the stone base-
ment of which 41, 6, or more circular holes are
seen, about 2 feet in diameter, resembling the
mouths of wells. These are the openings to separate
cisterns reserved for different qualities of oil. The
oil brought in a turbid state to these excellent
reservoirs soon becomes bright and yellow, and in
some cases may be kept for a period of 7 years.
It is carried thither in sheep or goat-skins, generally
on the backs of mules, and when it is to be shipped,
it is drawn off from the cisterns into skins, and carried
on men’s shoulders to a house on the sea-shore, where
there is a large open basin capable of containing
a given quantity, and of measuring the liquid, and
into that the porters empty their skins as they arrive.
A tube leads from the basin ,to a large cock on the
outside of the house. Under this cock are placed
casks of various sizes, and the oil is thus conveniently
drawn ofl" into them. Coopers are at hand to close
the casks securely, after which they are rolled down
to the beach, and being fastened, several together, by
ropes, they are attached to a. boat, which tows them
through the water to the ship’s side. The number of
persons employed in all these operations is very great,
and their cheerfulness, frequently exhibited by singing
in concert, gives a very lively efiect to the whole
scene. The produce of a full crop of oil, in the
province of which Gallipoli forms the chief outlet,
was, in 1843, nearly 22,000 tuns.
Fine Spams]; soap, known in England as OasZz'Ze
soap, is made of olive oil mixed with alkalies. A
similar manufacture is carried on at Marseilles, which
has a large export trade in soap.
Olive oil is largely used in Greece, Italy, Spain,
and France, as an article of food, and in medicine,
and the arts. It is extensively used in England,
especially-in the woollen manufacture. The fine oil,
called Florence oil, used for culinary purposes, is
brought from Leghorn in chests containing 30 bottles,
or 4: English gallons.
Oil of olives varies in colour from greenish to pale
yellow. A little above the freezing point of water it
begins to deposit some white granules of stearine.
At 22°, it deposits 28 per cent. of its weight of
stearine.
OMBROMETER. See RAIN-GAUGE.
z 2
340
OOLlTE—OPAL—OPIUM.
ONYX. See AGATE.
OOLITE. A species of limestone rock character-
istic of one of the great systems of secondary strata.
The stone is composed of globules or grains, clustered
together often without any apparent cement or base.
The resemblance of these grains to the ova or roe of
fishes, originated the English term oolz'le ((5511, an
egg), and the German Rogeaslez'a, or roestone. The
globules vary in size, from that of small pin heads to
peas. In some cases they occur in concentric layers,
in others they are compact or radiated. One of the
purest examples of oolite is the fine yellow freestone
of Ketton in Northamptonshire. It is composed of
round grains of concretionary structure, adherent by
their contiguous surfaces, forming an easily worked
durable stone. In the Bath freestone, the grains are
often hollow, and are connected by interposed calca—
reous matter. The Portland stone is similar, but
contains disseminated or aggregated silex. In the
Lincolnshire freestone the round grains are compacted
in a basis of crystallized carbonate of lime. The
oolitic series includes all the strata between the iron
sand above, and the red marl below. In the midland
and eastern parts of England, it yields admirable
building materials. It is divided into three systems :
——the upper, the middle, and the lower oolite. The first
includes the argillo-calcareous Purbeck strata, which
separate the iron and oolitic series; the oolitic strata
of Portland, Tisbury, and Aylesbury; the calcareous
sand and concretions as at Shotover and Thame, and
the argillo-calcareous formation of Kimmeridge. To
the second belong the oolitic strata, associated with
the coral rag; calcareous sand and grit; great Oxford
clay, which attains a thickness of 500 feet, between
the oolites of this and the following system. The
lower oolite contains numerous oolitic strata, and— is,
in some places, subdivided by thin argillaceous beds.
It includes the corn-brash (the uppermost bed);
then the forest marble, schistose oolite, and sand of
Stonesfield, and Hinton, great oolite, and inferior
oolite: calcareo-siliceous sand passing into the inferior
oolite: great argillo-calcareous formation of has and
has marl, which forms the base of the whole series of
the lower members of the oolitic system. The great
oolite is the most important, both in thickness and
practical utility. It is separated from the inferior
oolite by a series of marly beds, which contain among
them that particular kind of clay known as Faller’s
earl/1., and also a thin bed of calcareous flagstone
known as the Sloaesjlelcl slate. The inferior oolite
includes a thickness of about 110 or 50 feet of freestone.
On the continent of Europe the oolitic system is
known as Jara [cal/o and Oaleaz're Jarassz'gae, from the
conspicuous’ development of the strata in the Jura
mountains.
OPAL. This beautiful mineral consists of silica
with from 5 to 12 per cent. of water. It generally
contains a little oxide of iron, and a small quantity
of the alkaline earths. Eleven varieties have been
described. 1. Precious, or noble opal, is white, bluish
or yellowish white, and exhibits a beautiful variety‘
or play of colours, as blue, green, yellow, or red. The

fracture is conchoidal, with a vitreous or resinous
lustre. It scratches glass, but is easily broken on
account of the numerous fissures by which it is
traversed, and which probably give rise to the splen-
did play of colours. Opals are cut with rounded
faces.‘ The sp. gr. of precious opal is 206 to 2 09.
2. Fire opal. Gz'rasol, in which the internal reflec-
tion is bright red. It occurs with the precious opal
in Hungary, and has also been found in Cornwall.
3. Common opal, or semz'opal, has the hardness of opal,
and is easily scratched by glass, which distinguishes
it from some siliceous stones often called semiopal.
It has sometimes a milky opalescence, but does not
reflect a play of colours. 4!. Hpclroplzaae is usually
opaque, but by immersion in water, it exhibits the
iridescent colours of the precious opal. 5. Cae/zoloag,
first brought from the river Oach in Bucharia, re—
sembles chalcedony, but contains water and a little
alumina. 6. Hg/alz‘le, Maller’s glass, Flor'lle, a glassy
transparent variety, resembling transparent gum~
arabic. It occurs in small concretions, stalactitic,
and stalagmitic. ‘7. Meaz'lz'le, found in kidney-shaped
masses at Mount Menil, near Paris, is a brown opaque
variety, not unfrequently slaty. 8. Wood opal is
wood petrified with a hydrated silica: it is of a grey,
brown, or black colour, and has the structure of wood.
9. Opal-jasper resembles jasper, but contains iron,
and is not so hard. 10. Tales/leer, a siliceous aggre-
gation found in the joints of the bamboo. 11. Sili-
ceoas-sz'aler, deposited from hot springs, and near
volcanoes, has sometimes an opaline character.
OPIUM, an inspissated juice (duos, the juice),
from the capsule of the white poppy, Papaoer somat-
feram. It grows wild in some parts of England, and
is cultivated for its opium in Hindostan, Persia, Asia
Minor, and Egypt. In Europe the poppy is cultivated
for the capsules, either as medicinal agents, or for the
oil obtained from the seeds. The London market is
chiefly supplied with poppy-heads from Mitcham in
Surrey. The heads are usually collected when quite
ripe, but they would be more active as medicinal
agents if gathered while green. They vary in size
from that of a hen’s egg to that of the fist’. Their
texture is papyraceous, and on the top is a star-like
stigma. Their colour is yellowish, or yellowish brown,
and if collected before they are ripe they have a bit-
terish taste. When fresh they have a slightly opiate
odour, which disappears in drying.
The method of extracting opium is to a certain
extent similar in all countries: it consists in making
incisions in the half~ripe capsules, and collecting the
juice which exudes. The process, as followed in Asia
Minor, is as follows :—“ A few days after the flower
has fallen, men and women repair to the fields, and cut
the head of the poppy horizontally, taking care that
the incisions do not penetrate the internal cavity of
the shellf A white substance immediately flows out
and collects in tears on the edges of the cuts. In
this state the field is left for 2% hours, and on the
following day the opium is collected by large blunt
knives. : Each head furnishes opium once only, and
that to an extent of a few grains. The first sophisti- '
. OPIUM.
341
cation which it receives is that practised by the pea-
sants who collect it, and who lightly scrape the
epidermis from the shell to augment the weight.
This operation adds about 115th of foreign matters.
Thus collected, opium has the form of a glutinous and
granular jelly. It is deposited in small earthern
vessels, and beat up with saliva. When asked why
water was not employed in the place of saliva, the
answer was that water caused it to spoil. It is after-
wards enveloped in dry leaves, and in this state it is
sold. The seeds of those poppies=which have yielded
opium are equally good for sowing the following
year.”1
Several varieties of opium are known in commerce.
The principal kind is that from Smyrna, known as
Tur/rey or Levant opium. “ It occurs in irregular
rounded or flattened masses of various sizes, rarely
exceeding 2lbs. in weight, enveloped in leaves, and
usually surrounded with the reddish capsules of some
species of Rumea'. Some of the flat cakes are without
these capsules, and somewhat resemble Constanti-
nople opium. When first imported the masses are
soft and of a reddish-brown colour; but by keeping
they become hard and blackish. Its lustre is waxy;
its odour is strong and unpleasant ; its taste is bitter,
acrid, nauseous, ‘and persistent. M. Guibourt regards
the masses as being made up of agglutinated tears,
and on this account as being the purest met with.
It is, however, frequently met with largely adulte-
rated. In one sample, weighing 10 ounces, I obtained
10 drachms of stone and gravel. Notwithstanding
occasional frauds of this kind, Smyrna opium forms
the best commercial opium.” (Pereira) It yields
more morphia and meconic acid than either Constan-
tinople or Egyptian opium. It yields about 8 per
cent. of morphia on the average. Of Constantinople
opium there are two sorts: one in large irregular
cakes; this is of good quality. The'other, in small
flattened regular cakes, of a lenticular form, from 2
to 2-12- inches in diameter, covered with a poppy-leaf.
Egyptian opium occurs in round flattened cakes of
about 3 inches diameter. It is inferior to the
Constantinople opium, and is said to yield only iths
of the morphia obtained from Smyrna opium. Trebi-
eon or Persian opium, also inferior, has been imported
in the form of cylindrical sticks, each enveloped in a
smooth shiny paper tied with cotton. Of Indian
opium there are 3 varieties, the Malioa, Benares,
and Patna, the two latter being included under
Bengal opium. The latter is imported in balls of
about 3glbs. weight, packed in chests of 40 balls
each. “ The balls are hard, round like cannon balls,
and about the size of a child's head. Externally, each
ball is made of poppy petals, firmly agglutinated by
a paste, called Zezoa, to form a firm but laminated
envelope, weighing about 14: oz. On cutting through
this the opium is found to be quite soft, homogeneous,
apparently quite pure, and to have the consistence of
a soft extract. Its colour is blackish brown. Its
odour and taste are strong and pure opiate. On ex-

(1) Tcxier, Journal de Pharmacie, Quoted by Dr. Pereira, Ele-
ments of Materia Medica, vol. 1842.

posure to the air this opium speedily becomes covered'
with mouldiness.” It is said that this opium contains
from 2%— to 3 per cent/of morphia, but Dr. Pereira
regards this as being‘ considerably below the truth.
There is also an EnyZis/z, a French, and a German
opium, but the quantities are inconsiderable although
the qualities are good. ‘
Opium has long been known for its energetic action
on the animal system. When taken by man in small
doses, as from %grain to 1 grain, it generally acts as
a stimulant, and produces pleasurable excitement;
but the dose must be increased in order to produce
the same effects. When a full medicinal dose (as from
2 to 4.- grains) is given, the stage of excitement is
soon followed by that of depression. The skin be-
comes hot, the mouth and throat dry, the appetite
diminished, the thirst increased, and nausea or vomit-
ing is frequently induced. A state of torpor then
comes on, followed by sleep with pleasing or frightful
dreams, and on waking there is frequently nausea,
furred tongue, headache, and listlessness. A larger
dose produces death in persons not accustomed to it;
but, unfortunately, the habit of taking opium habitu-
ally (opium-eatiny) is not uncommon even in England.
It is first resorted ‘to for the relief of bodily suffering,
and the habit, once began, is seldom relinquished.
The following description may be taken as a warn-
ing :—“ The habitual opium eater is instantly recog-
nised by his appearance. A total attenuation of body,
a withered, yellow countenance, a lame gait, a bend-
ing of the spine, frequently to such a degree as to
assume a circular form, and glossy deep-sunken eyes,
betray him at the first glance. The digestive organs
are in the highest degree disturbed, the sufferer eats
scarcely anything, and has hardly one evacuation in
a week: his mental and bodily powers are destroyed,
he is impotent. By degrees, as the habit becomes
more confirmed, his strength continues decreasing,
the craving for the stimulus becomes even greater,
and to produce the desired efl’ect, the dose must con-
stantly be augmented.”
Large quantities of opium are consumed in China
and the islands of the Indian Archipelago, by smoking.
“ The smokable extract, called cnandoo, is made into
pills about the size of a; pea. One of these being put
into the small tube that projects from the side of the
opium pipe, that tube‘ is applied to a lamp, and the
pill, being lighted, is consumed at one whifi or infla-
tion of the lungs, attended with a whistling noise.
The smoke is never emitted by the mouth, but usually
receives vent through- the nostrils, and sometimes, by
adopts, through the passage of the ears and eyes.
The residue in the pipe is called tye-ct'andoo, or faecal
opium, and is used by poor persons‘ and servants.”
The effects on the system are extremely baneful.
The peculiar properties of opium are due to the
presence of several alkaloids, the chief of which are
morptine, narcotine, and codeine. Others of less im-
portance are obtained in small quantity, viz. t/zebaine,
,01‘ paramorpizine, narceine, pseudomorp/zine, and a crys-
talline substance, containing no nitrogen, which acts
the part of base 5 it is called meconine.
342
OPIUM.
Marja/zine. In order to extract the morphine, the
opium is cut into thin slices, which are macerated in
water until sufficiently soft; it is then made up into
a pulp with more water, put into bags, and subjected
to strong pressure. The mare, or contents of the
bags, are treated with water and again pressed. The
expressed liquid is evaporated to the consistence of
an' extract, from which the salts of morphine are dis-
solved out by means of a small quantity of water,
leaving the greater portion of the narcotine mixed
with a brown matter. Trial is made with a small
portion of the liquor how much ammonia is required
exactly to precipitate the morph-‘ia: the third of this
quantity is first added, which throws down an impure
morphia, dragging with it nearly all the colouring
matter. The remaining portions of the ammonia pre-
cipitate nearly pure morphine. This is treated with
dilute alcohol (20° Baumé), which does not dissolve
any ‘sensible quantities of morphine, but removes
almost entirely the resinous m atter with which it is
entangled. The residue is treated with boiling alcohol,
of 35° Baumé, which dissolves the morphine, but
deposits the greater portion of it in cooling. Three-
fourths of the alcohol are separated by distillation,
and the remainder gives up the morphine; but in
order to obtain this base completely pure, it must
be dissolved in weak hydrochloric acid, crystallized,
and decomposed again by means of ammonia. Mor-
phine crystallizes with facility. Its crystals con-
sist of C34 H18 NOs+2HOz they readily part with
the two equivalents of water by the action of heat,
and can then be raised to the temperature of 572°
without decomposition. Cold water dissolves about
1010 0th of morphine; warm water nearly double that
quantity; the solution restores the blue colour to
reddened litmus. Dilute alcohol (20° Baumé) dis-
solves only' a small quantity of morphine; boiling
alcohol (35° Baumé) dissolves g-O-th of its weight, but
the greater portion of the morphine crystallizes on
cooling. Ether has scarcely any action on it. A
concentrated solution of caustic potash dissolves mor-
phine without change, a property which allows this
base to be separated very exactly from narcotine,
which is not soluble in alkaline menstrua ; morphine
dissolved in acidulated water and’ exposed to the
action of polarized light turns the 'plane of polariza-
tion to the left: its salts exert the same action.
Morphine forms withiacids crystallizable salts, which
are soluble in water and in alcohol, but insoluble in
ether. The izyclroc/tlomzfe of morphine is used in
medicine, it crystallizes in slender colourless needles,
arranged in tufts or stellated groups : it is soluble in
about 20 parts of cold water, and in its own weight
‘if boilingwater. The sulfa/tale, nitrate, and phosphate
are crystallizable salts. The acetate crystallizes with
difiiculty.
Narcoz‘z'rze. 'This is obtained from the mam, or
insoluble portion of opium left in the preceding
operation. This is treated with ether, which dissolves
a mixture of narcotine and porphyroxine in which
the narcotine prevails. Fresh opium may even be
treated in this-way; the salts. 'of morphine remain

behind, and the ether contains with narcotine and
porphyroxine a certain quantity of meconine. The
ether is distilled at the water bath; the residue is
treated with water, which dissolves the meconine; and
lastly, the narcotine and porphyroxine are dissolved
out by dilute hydrochloric acid. The solution on
being evaporated leaves hydrochlorate of narcotine,
and the hydrochlorate of porphyroxine remains in the
mother liquor. The hydrochlorate of narcotine de-
composed by ammonia gives narcotine in an isolated
form: it may be purified by crystallization in alcohol.
It ' crystallizes in small colourless brilliant prisms,
which are nearly insoluble in water. The basic powers
of narcotine are very feeble, and although freely soluble
in acids 'it seldom forms with‘ them crystallizable
compounds. Narcotinc consists of 046 H25 NO14:
it rotates to the right as do also its salts.
Codeine, C34H19 N05. This substance remains in
the liquors after morphine has been precipitated by
ammonia. These liquors are evaporated, caustic potash
added, and the evaporation continued to dryness.
The residue is treated with ether, which dissolves the
codeine, and this crystallizes by spontaneous evapora-
tion into colourless transparent octahedrons. Codeine
is much more soluble in water than the other alkaloids
of opium: it dissolves in 80 parts cold water and 20
of boiling water, and it is very soluble in alcohol and
ether: it has a strong alkaline reaction, and forms
crystallizable salts.
Mecca-me (from Meow, a poppy) is obtained by
digesting opium in cold water, filtering the infusion,
concentrating it by evaporation, and adding ammonia
as long as a precipitate is produced. After some days
the supernatant liquid is poured off gently, evaporated
to the consistence of syrup, and left in a cool place
for 15 or 20 days, when it deposits granular crystals,
which are collected, drained, pressed, and dried by a
gentle heat. They contain meconine, narceia, and
other substances; they are boiled in alcohol, and the
solution is evaporated to about one~third its bulk,
when on cooling it deposits crystals, which are col-
lected, dissolved in boiling water, and filtered with
animal charcoal; white crystals are obtained of
meconine and narceia; ether dissolves the former
and leaves the latter: on evaporating the ethereal
solution, the meconine remains. It is white, inodorous,
slightly acrid, soluble in water, alcohol, and ether,
and crystallizable.‘ _ '
Meeom'e aez'd, C14 HO113HO, is also obtained from
opium. When chloride of calcium is poured into an
infusion of opium, a precipitate of ‘impure meconate
of lime is formed, which is first washed with water,
then with alcohol. After this it is treated with 20
parts warm water to which are added 3 parts of
hydrochloric acid: the filtered liquor leaves on cool-
ing an acid meconate of lime. This salt is digested
with a similar quantity of warm acidulated water, and
meconic acid separates on cooling. This operation
must be repeated once or twice to obtain the acid
entirely free from lime. Meconic acid crystallizes in
small colourless pearly scales, which dissolve in 41 parts ‘
of hot water. It has an acid taste and reaction,-
ORGAN.‘
are
forms soluble compounds with the alkalies; and in-
soluble salts with lime, baryta and the oxides of lead
and silver. With a salt of peroxide of iron, meconic
acid strikes a deep blood-red colour, resembling that
developed under similar circumstances by a sulpho-
cyanide; but the addition of corrosive sublimate
bleaches the sulphocyanide, but has little effect on
the meconate.
There are many other substances derived from or
connected with opium, for an account of which we
must refer to chemical works.1
ORCHIL. See Ancnin.
OECINE. See Ancn'IL.
ORE. See MnrALLuneY—Mrnrne.
ORGAN. The organ is a complex wind-instrument,
consisting of a large number of pipes of different sizes,
materials, form and arrangement, made to sound by
means of compressed air supplied to them through
certain channels by bellows. There are different kinds
of organs, such as the small curl-organ, the chamber-
orguu, the smaller c/zapel-orgau, and the great cture/z-
orgau: there is also the barrel-organ. The organ is
so well known by its external form, and ,the sublime
and beautiful effects which it produces in our public
worship, that few persons will fail to be pleased with
a knowledge of the numerous ingenious mechanical
arrangements which belong to its internal structure,
and which enable a single performer to throw out the
floods of sound and intricate harmonics of a full
orchestra.
The early history of the organ is obscure. It ap-
pears that a small and imperfect instrument of the
kind was known to the ancients: thus we read of
lzg/clruulz'c organs and pneumatic organs, but as the
passage of water through the pipes would not pro-
duce musical notes, we are led to believe that water
was employed as a moving power to impel wind into
the pipes. The term pueumalz'c is still sometimes
applied to the modern organ, to indicate that wind is
the moving power, so ‘to speak, of the instrument.
With respect to the term organ, the Greek word
iip'yazlov, the Latin orguuum, and the English organ,
originally signified an instrument or machine of any
kind. The term was afterwards limited to musical
instruments used to accompany the voice in singing;
it was afterwards restricted to wind-instruments, and
in modern times to the instrument now'reeognised as
such. The term occurs three times in our version of
the Old Testament, viz. in Gen. iv. 21, Job xxx. 81,
and Psalm cl. 4:. The‘ instrument here alluded to
was probably the syrz'uu', .Pau-pz'pes, or mouth-organ,
consisting of several reeds, of different lengths, joined
together, closed at one end; and the sound produced
by directing a thin stream of air from the lips into
the open end. This simple instrument, and the bag-
pipes, were probably the immediate predecessors of
the organ.
The earliest notice that can be at all relied on of
the introduction of the organ into the churches of
Vllestern Europe is, that about the year 7 57, the

(1) See Gregory's Outlines of Chemistry. Brande’s Manual of
Chemistry, and Pereira’s hiateria Medica.
' king of France.

emperor Constantine V. presented one to Pepin,
In 812 Louis-le-Débonnaire caused
one to be built at Aix-la-Chapelle on a Greek model,
and this is supposed to have been the first that was
used with bellows without the use of water. Previous
to the tenth century organs were commoninEngland.
St. Dunstan gave one to the abbey of Mahnesbm'y.
Elfeg, bishop of Winchester, in 951, obtained one for
his cathedral, the largest then known. The organs of
this period were rude in construction: the keys were
A or 5 inches broad, and were struck with the clenched
hand after the manner of carillons ; the pipes were of
brass, harsh in sound, and the compass, even so late
as thetwelfth century, did not exceed 12 or 15 notes.
About this time half-notes were introduced at Venice,
at which place was also made, in 1470, by Bernhard,
a German, the important addition of pedals or fool-keys;
The gradual improvements in the construction of
organs may be traced in those erected at Dijon in the
13th century, at Halberstadt in 1360, and at Nurem-
berg in 1468, about which time large pipes of 16 and
32 feet began to be made. The description of an
organ at Breslau, in 1596, shows that at that time
all the principal stops now in use were known, and
that the present general arrangement and details of
a large organ were then adopted. After this time the
chief improvements were mechanical.
Little ‘is known respecting organs in this country
from the time of the Reformation to the reign of
Charles I. There was a great demolition of organs
in the time of the Puritans; our organ builders be-
came carpenters and cabinet-makers, so that at the
Restoration only four organ builders of eminence sur-
vived. This led to the introduction of foreign artists,
such as Bernard Schmidt (called “Father Smith”),
and his two nephews; the elder Harris, and his son
Renatus. Some of the organs of these skilful mecha-
nicians still exist in London, Oxford, 850. Schreider,
Smith’s son-in—law, built the organ in Westminster
Abbey, and that at St. Martin’s in the Fields. Snetzler,
Byfield, and others, and, at a later period, Green,
Avery, Gray, Elliot, 850., were celebrated as organ
builders. By these makers, and some of the most
eminent of Germany and Italy, the mechanism of
the modern organ was greatly improved. Among
the earliest famous builders in Italy in the 15th and
16th centuries is the family of the Antegnati of
Brescia. In the 18th century the most celebrated
builders were Serassi of Bergamo, and Callido of
Venice : each constructed upwards of 300 organs.
When a person, unaccustomed to the study of me-
chanism, siu'veys the interior of an organ case, the
arrangement appears to be so exceedingly complex
that he is likely to turn away, impressed with the
idea that it cannot be understood except by profes-
sional men. And yet the principle of the organ is
sufficiently simple: only, this principle being carried
out to its utmost extent, a complex appearance does
arise from the multiplication of similar or nearly
similar parts, and from the contrivances made for the
sake of economy of space. In a great church organ,
such as we propose very briefly to describe, there are
3.4141
ORGAN.
several thousand pipes, and arrangements for enabling
the performer to operate upon any single pipe of the
number without interfering with the others :_ hence
there are numerous levers and rollers, quadrants and
rods, slides and partitions. Now to take the simplest
case: In order to make one pipe sound or speak, there
must be, 1, a bellows for supplying condensed air or j,
wind; 2, a channel for conveying it to the pipe in
question; 3, some contrivance, such as a valve, for
admitting. the wind to this pipe when it is required
to speak, and for cutting ofi’ the supply when required
to be silent; 4d, a lever for opening or shutting this
valve. These, and other contrivances yet to be named,
for producing variety of effect, loudness or softness,
qualities of tone resembling various musical instru—
ments, &c., necessarily require the introduction of
a good deal of mechanism and a great repetition of
parts. We will endeavour so to describe the sepa-
rate parts of the organ, as to give the reader a
general idea of the construction of this instru-
ment.
And first with respect to the pipes, the grand
assemblage of which constitutes the organ. There
are two general descriptions of pipe, the moat/i or
flute pipe (technically flue) and the reed pipe, each
comprising several different species.
Mouth-pipes, or pipes with a mouth and lips similar
to the flageolet, may be of wood or metal: they differ
somewhat in shape, but are formed on the same
principle. The shape of the metal mouth-pipes is
well known, since they are used to decorate the front
of the organ-case. The wooden mouth-pipes consist
each of a four-sided trunk or chest, formed by glueing
4: plane boards together: the cross section is not
square, but oblong, one side being to the other in the
proportion of 5 to 1i. The interior is usually sized
with glue. The upper extremity may be open, or
closely'stopped by means of a plug, called a iompioii,
t, Fig. 1538, made to fit air-tight by being covered
with leather. The other end of the tube is also closed
by means of a block b, on which 30f the walls are
glued, except at the narrow
aperture or mouth in across the
front wall. The mouth is formed
by cutting off in a sloping direc-
tion or bevel a portion of the
front wall, a little above the
upper part of the block, so as to
form a sharp edge with the back
or inner surface of the wall: this
sharp edge is called the upper Zip
or wind-cutter. The side and
, back walls also embrace another
block p, arranged so as to form
with 6 a narrow space. The
foot f of the pipe is fixed in this
lower block : this foot is a hollow
cylinder open at both ends, the
lower end formed so as to fit
into the apparatus which supplies
the pipes with wind. The front
‘of the pipe, from the mouth downwards, is covered





Fig. 1537. .Fig. 1538.

by the cap a, Fig. 1537, consisting of a piece of
mahogany somewhat thicker than the walls. It is
hollowed out so as to leave edges for glueing upon
the edges of the side walls and the block into which
the foot is inserted, but leaving the aperture quite
free. When the cap is screwed on, a thin aperture is
left between it and the block [2, called the plate of
wind, which, when the foot f is supplied with air, is
forced in a thin stream against the upper lip or wind-
cutter; and the vibrations which it thus receives it
imparts to the whole column of air in the pipe; the
result of which is a musical note, depending for its
pitch upon the length of the column thus set in
motion. A gopd quality of sound is produced by
what is called voicing the pipe; that is, before the cap
is put on, the upper corner or edge of the block is
slightly pared away opposite the upper lip, so as to
direct the wind against its inner edge. Skill and
experience are required in this operation; for if too
much or too little be pared away, the pipe will be
slow to speak, or not speak at all, or speak badly.
The upper part of the block is also toothed with the
edge of a file into thin cuts or lines, forming acute
angles with the under lip, for the purpose of dividing
the plate of wind ; for if suffered to strike against the
upper lip undivided, it would form an unpleasant
chirping at the commencement of the note. The
width of the mouth, or the distance of the upper lip
from the plate of wind, is of importance to good
speaking: if too great, the pipe may be slow to
speak, or not speak at all; if too narrow, an open
pipe may give the octave or double octave, and
a stopped pipe the twelfth of the note intended to be
produced.
The pitch of the note depends on the length of the
pipe above the mouth. If the length be doubled, the
vibrating column of air is also doubled, and the pipe
gives the octave lower; so by halving the length of a
pipe, it speaks an octave higher. If we call the
length of the pipe for the lower octave 1, then that
of the octave above will be 317, and the lengths of the
pipes required to fill up the interval will be re-
spectively, gths, g-ths, efiths, g-ds, g-ths, and -,-85-ths. So
also if we represent the number of vibrations required
to produce the lower octave by 1, double that number,
or 2, will represent the number of vibrations in the
octave above; and those of the intermediate numb er
of vibrations between the two octaves will be repre-
sented by the reciprocals of the above fractions,
viz. %ths, fi-ths, igds, gds, %ds, and Jg-Sths. The lowest
audible note, however, is not produced by 1 vibration
per second, nor by its octave 2, nor by its octave 4‘,
nor by 8, but by 16 single or 32 double vibrations1 per
second. This forms what is called the 0 below, and
is produced by an open‘ pipe 32 feet long. The octave
of this, 64 vibrations per second, is the lowest 0 of a
grand pianoforte, and is produced by an open pipe 16
feet long. Then we have— ‘

(1) This refers to a. stretched string, in which at each double
vibration two impulses are given to the air, one on each side of
-the axis of the string; one such impulse constituting the single
vibration.
ORGAN.
345
123 vibrations: the lowest note of the Violoncello {gnfeoelzefisge
256 ,, ' = tenor C,the lowest note ofthe viola 4 ,,
512 ,, === middle C, the note of the C clef... 2 ,,
1024 ,, == 0 on the 3d space in the treble clef 1 ,,
2048 ,, = C in % foot long.
In speaking of the stops of an organ, it is usual to
express the notes by the lengths of pipes corresponding
to them : thus the lowest 0 of a grand pianoforte is
called on the organ 16-feet 0; middle 0 is called 2-feet
o, and so on. All this refers to open pipes. The effect
of stopping them at the top is at once to lower their
pitch a whole octave; and the reason is evident: the
wind not being able to escape at the top of a stopped
- pipe, returns, and gains an exit at the mouth, thus
actually doubling the length of the vibrating column,
and making its vibrations proportionally slower. This
valuable property allows of considerable economy of
space in the construction of the organ, because a
stopped 16-feet pipe emits the same note as an open
32-feet pipe, and a stopped 8-feet pipe gives the same
note as an open one of 16 feet, and so on.
With regard to the quality of the tone or timtre
of a pipe, this depends greatly on the size of the tube;
and as it is of importance to have the same quality for
all the notes of the same stop, scales of sizes have
been formed for the use of the orgainbuilderz these
scales vary with the size of the organ. The kind of wood
used has an influence on the tone of wooden pipes.
Mahogany or wainscot pipes give a clearer tone than
pipes of fir ‘or other soft wood; but the latter are
more mellow. The notes are regulated as to loudness
by enlarging or diminishing the aperture in the foot,
whereby more or less air is admitted. The stopped
pipe is tuned by means of the tompion or plug. By
pushing this deeper into the tube, the effective length
of the column of air is shortened, and the resulting
note will be more acute; by drawing up the plug,
the note will be graver.
The structure of metal mouth—pipes, Figs. 1539,
15410, is somewhat different. They are nearly closed
.._....- ______
_,___~\_.~..._-_." Mqrzwefl—M '__ “4.01:1. _ -

W-
M ‘7W’ _-1W"MW>,W.- ' -c~r M, ——'——¢—-. . may? .
I
7:,“


Fig. 1539. Fig. 1540. Fig. 1542.
at the base of the cone by a thick metal plate or
Zanyuette, Z, Fig. 1539, answering the purpose of the

block in the wooden pipe; A thin slit is left, by
means of which a plate of wind is formed with the
under lip. The voicing is performed by making
parallel notches on the bevelled surface at an angle
with the axis of the pipe. The cars ee are of soft
metal, so that by bending them more or less over the
mouth the tone is modified as required.
Another form of mouthpipe is the c/timney top,
Figs. 154:1,‘ 1542'. Such pipes have a small open
tube 0 in the middle of the top plate, the effect of
which is to make the note considerably sharper than
if quite stopped; an effect which is sometimes pro~
duced in stopped wooden pipes by boring at small hole
through the tompion.
The structure of reed'pipes is very different from
that of mouth-pipes. In reed pipes, Fig. 1543, there
is a brass cylindrical or slightly conical tube or
reed r, with a longitudinal narrow opening ,8
in front. The lower extremity is cut slanting
upwards and backwards, and is closed by a
piece soldered on it. The long opening is 5
covered by a thin plate of metal t called a
tonyue : it is kept firmly to the reed at its
0
"h
upper end, but is free at the lower end, and r
slightly curved away from the reed. This little
piece of apparatus is firmly fixed to a solid
block 6, the open end passing through it.
Through the block also passes awire s s’, bent Fig 1543.
up so as to press firmly against the top of the
tongue and keep it close to the reed; so that by
pushing down or drawing up this tuning wire, as it
is called, the free part of the tongue is made shorter
or longer. The block containing the reed, &e. is in-
serted in or just above the cone or foot of the
pipe, the large end of which is thus completely
closed. The wind is sent in at the point of the cone.
The tube above the cone is variously shaped, and
upon it depends the quality of tone in reed-pipes, the
pita/z depending entirely on the length, thickness, and
elasticity of the tongue of the reed. The first action
of the wind is to press the tongue against the reed
and close the opening; the elasticity of the tongue
immediately causes it to rebound and pass beyond its
position of repose : it then returns, and, as the wind
still exerts its force, it is again driven against the
edges of the reed, and thus a musical note is produced,
which is acute or grave according to the length of
tongue left free to vibrate below the tuning spring.
The structure of the reed was improved many years
ago by M. Grenié, who, instead of making the tongue
heat on the edges of the opening, formed it
just within the opening, so as nearly to close
it, and thus to play freely backwards and
forwards in and out of the same. The
tongue t, Fig. 15%.‘, is a perfectly flat plate
of brass, rectangular in shape, and the
tuning spring 8 s’ is very firm and solid, so as
to stop the tongue at the proper length and
fix the point from which it is to vibrate.
The tongue thus playing rapidly in and out
of the opening of the reed, instead of heat
ing on the reed itself, throws the current of


34:6
.ORGAN'.
air which" passes ' through the reed into vibration,
as in the beating reed, but produces a more sweet,
harmonious, and equal tone, since the plate, instead
of beating against wood or metal, the resistance
of which is sudden and .irregular, only causes the
air, which is perfectly homogeneous, compressible,
and elastic, to recoil upon itself ; and hence the sound
is as sweet as in mouth-pipes. . By having a firm
spring, the pipe cannot octa/oe und'er increased pres.-
sure of wind, but can only become increased in- loud-
ness. .' The free reed is less liable to get out of
tune than the beating reed. Moreover, the latter
gives only one quality of tone, of the same degree of
loudness, while the free reed admits of expression,
.that is, by varying .the pressure of the wind, crescendo
and dz'mz'nnendo effects may be produced. The free
reed attracted but little notice for many years after
its invention; but it is now used in organs by foreign
builders. The French and German organs in the
Great Exhibition contained free reed stops; but the
principle has not yet been adopted by English organ-
builders.1
The air which causes the reeds to vibrate, escapes
by open tubes increasing into a cone, and terminated
in a hemisphere, a form which gives roundness and
force to the sound. The length of each tube is
equal to that of the tongue. In constructing his
reed stops, M. Grenié began withthe lowest octave
of which 0 is unison with an open mouth-pipe of 8
feet: and he had constructed a certain number of
notes by giving the wind to his reeds by port-vents
or sockets of the same length, Fig.
1545. But when he came to the first
notes of the tenor, continuing to
make his port-vents in the same
manner, the reed would not speak.
He increased and diminished the
.wind, lengthened and shortened the
tongue, to no purpose. At last, supposing the length
of the tube which conveys the wind to the reed might
Fig. 1545.

(1) Mr. Bishop informs us that the free reed has from time
immemorial been used by the Chinese in a small instrument called
the Chinese organ. M. Grenié introduced the free reed in 1810, and
constructed two instruments on this principle, one of which was
sent to the Conservatoire des Arts, 850-. In 1827,' three free reed
stops were introduced into the organ at Beauvais Cathedral, and in
1829, M. Sebastian Erard introduced a free reed stop into an organ
built by him for the Tuilei'ies : in this stop the expression was made
to depend on the touch. After this the application of the free reed
to the organ was forgotten ; but the reed itself became in a very
remarkable manner the basis of avariety of new instruments, such
as the accordion, Wheatstone’s wolz'na, which soon led to that
exquisite little instrument, the conccrtina. The attempts made to
improve the accordion by enlarging and completing its scale, made
it so unwieldy that it naturally took the form of an organ with a
free reed stop, without pipes, with bellows worked by the foot:
such was Mr. Green’s sercophz'ne. Varieties of this instrument have
since appeared, under the forbidding names of ceoloplzon, pkg/ska?‘-
mom'ca, wolomusicon, and poikilorguc ; and the more euphonious
appellations of Izm'moninm, melodium, and symphonz'um. We have
also a folding harmonium, and an argue de voyage, or travelling
organ. The folding harmonium exhibited by Messrs. Wheatstone
at the Great Exhibition has a compass of 5 octaves, and when
expanded for use is 41 inches long, 10 inches deep, and 25 inches
high. It is ingeniously contrived-s0 as to fold in the middle of
the clavier, and also underneath, by which its dimensions are
reduced to 2"] inches long and 10% inches high, or a little larger
than an'ordinary writing~desk; . -
have some influence on its motion, he substituted for
his fixed tubes, one sliding within the other, so that
he could gradually vary the total length 5 and. he con-
tinued his trials until the reed gave a brilliant, pure,
and sustained sound. He also found, that in order
to obtain the fullest tenor, it was necessary to make
the port-vent much longer than for the note immedi-
ately preceding, and this length went on diminishing
for the more acute
octaves, as shown
inFiglMfi. The
tops of his pipes
were curved as at
r T’ T", which
seemed to indicate
that by prolong-
ing this curve,
dimensions would
be obtained most
favourable for the
pipes of the first
octave, which at first were made of equal length
This led to no advantage, but on the contrary, the
sounds were bad. He therefore kept to his first
construction, and purposed to make his port-vents
double, and sliding, so as to be able to give to each
the best length. ' Reed-pipes on this model give
the note of the 16-foot open pipe with remarkable
distinctness, power, and regularity. The tongue is a
plate of copper 946 inches long, 1'38 inches broad,
and 0'118 inch thick. Its vibrations are described
as being so powerful, that they cause to tremble the
pipe, the port-vent, and every elastic body in the
Vicinity.
Now, it will be evident, that with as many sets of
pipes as there are octaves in the key-board of the
pianoforte, each octave giving the 12 notes of the
chromatic scale, an organ of the simplest kindlwould
be formed; and if the key-board of such an instru-
ment were as extensive as that of the pianoforte, it
would be as complete as that instrument as far as
regards scale. But in an organ there are a great
many sets of pipes or stops, as they are called, the
corresponding notes of which agree in pitch, but
difier in the timbre or quality of tone. Each stop,
then, is a range of pipes of the same quality of tone
extending throughout the compass of the organ.
When a certain stop is drawn, the keys will play
throughout on pipes of that character of which the
stop consists. Stops differ in pitch and in timbre, so
that the same key will sound different notes, accord-
ing as different stops are drawn. The mode in which
stops are designated, “ is by stating the interval
which any note of the given stop makes with the
fundamental note corresponding to the key struck.
Thus, when the key middle 0, or 2-foot c, is struck,
a certain stop will sound the e at an interval of a
twelfth above: this stop is therefore called the twelfth.
Another stop will sound the 0 two octaves above,
' and is therefore called the fifteenth. The stops which
sound the fundamental note itself, would be on this
'12
fit
7
f“?
7
i I
\\’


I
Fig. 1546.

; principle designated unison, and those' sounding an
a
ORGAN.
34’?
octave above it, would be called oei‘uue. For the
stops sounding an octave below the fundamental note,
the word cloulle has been used, and though not
correct in principle, it may be considered as sanc—
tioned by custom.” 1 The tone of every key in a large
organ consists of notes of several pitches combined,
so as to blend together into one sound: that is, in
addition‘ to the fundamental note there are other notes
forming harmonic intervals with it. Thus, the funda-
mental note (8 feet pipe), its octave (41 feet), its
twelfth (‘2%— feet), and fifteenth (2 feet), form a good
organ of moderate power. But in large organs there
are also compound stops, consisting of various combi-
nations of the intervals of the major common chord,
or third, fifth and eighth in octaves above the fifteenth,
producing by their combination great brilliancy of
sound. But in ascending in the scale, the effect was
found to be too shrill, and accordingly weight‘ was
given by adding the octave below, or 16-foot stop.
This not only produced a brilliant and powerful effect
adapted to large edifices, but allowed of the intro-
duction of other intervals, such as the fifth (5% feet),
and tenth ( 3.}; feet) of the fundamental note. The
small'compound stops are usually so arranged, that
one draw-stop serves for several ranges of pipes.
The reeds, which greatly reinforce the power of a full
organ, are used in the form of 16 feet (double), 8 feet
(unison), 41 feet (octave), and sometimes 2 feet (fif-
teenth) stops. In addition to these, there are solo
or fimoy stops, generally either 8 feet or 4h feet in
pitch, both of the flute and the reed kind. The
variety is given to the flute stops by the scale, the
material, or the form of the pipe, and by the voicing.
“ The delicate silvery sound of the stop called the
eluleiuuu, is produced by an open metal pipe of very
small scale; and an agreeable kind of tone has been
lately obtained by a pipe pierced with a hole in its
side.‘ A fine stop used by the French, is produced
by making the pipes over-blow, as it is called, so as to
sound an octave higher than the note due to their
length.” Among the reeds named from the instru-
ments which they imitate, the effect is produced-

chiefly by varying the form of the tube. The ordi-
nary tube is conical; the oboe stop, Fig. 15417 , has a bell
mouth, and a conical tube, and gives a tone resembling
the oboe. Figs. 15418, 1549, show the form of the
(1) N ewton’s London Journal, vol. xxix. In the papers con-
tained in this Journal on the Great Exhibition, are some admirable
' Essays on the “ Musical Instruments” exhibited. Those on the
organ have furnished us with some valuable hints. While on the
subject of references, we must notice the great deficiency of works
on the organ in the English language. There are some good essays
on the organ in Rees’s Cyclopmdia, the Edinburgh Encyclopaedia,
and the Encyclopadia Britannica, all of which we have consulted,
and are indebted to the first two for many of our figures. The
French and Germans are singularly rich in works on the organ.
In the former must be noticed, L’Art du Facteur d’Orgues, by
Bedos de Celles, a Benedictine Monk, in two folio volumes, Paris,
1766-17 70, with 137 plates. In German, the Abbe Vogler has
several works on Organ Building. But many of the fine treatises
which might be quoted, are not accessible to the general reader. We
therefore recommend him to a cheap but excellent work in the
Encyclopedia Roret, largely compiled from the work of Bedos de
Celles, and entitled Nouveau Manuel _ Complet du Facteur
d’Orgues, par M. Hamel. 3 vols. 1849, with an Atlas, containing
nearly 1,000 figures in 43 large plates.

trumpet pip'e. "Fig. 1550, ‘the orom'orutl or ereuzouu,
which has a sound resembling that of a clarionet.
Fig. 1551, the ‘bassoon, and Fig. 1552, the 210:1: kumomu,
from its supposed resemblance to the human voice.
Referring to Fig. 1555, which represents the end
pipes of the rank of pipes or stops mountedon the
sound board over the wind aw chest, &c., we
will briefly recapitulate the most usual
organ stops: these are, I. Open dz'apusou
(marked 0 D in the engrav- ing); this con-
sists of metal mouth-pipes, \ open at the
l



Fig.1547. Fig.1548. Fig.1549. Fig.1550. Fig.1551. Fly. 1552.
upper end, and extending through the whole scale of
the organ, as its name elz'apusou implies. II. Stopped
clz'apasou (s n); mouth-pipes generally of wood, their
pitch being in unison with I. : they are plugged at the
upper end. III. Double elz'apasou ,- wooden mouth-
pipes open at the upper end, their pitch being an
octave lower than I: they are usually confined to the
two lowest octaves of the organ’s compass. In the
largest organs the gravest sound is produced by an
open pipe 32 feet long. Iv. Prz'uez'pul' (marked P);
metal mouth-pieces, the pitch of which is an octave
above I. This is the first, or medium stop, which is
tuned, all the other stops being tuned from it.
v. Dulez'uuee ,- a metal mouth-pipe stop, tuned in‘ uni-
son with I. The length and narrowness of its pipes
produce the sweetness of tone from which it is named.
VI. Twelfth (marked 12) ; metal mouth-pipes, tuned a
twelfth above 1. VII. Fg'fieeuzfl. (marked 15); metal
mouth-pipes, tuned an octave above IV. In some
organs are stops named fierce or seueuleeul/l, larz'got
or uz'ueleeul/z, lweuly-seeouzl, twenty-sight, twenty-mull,
thirty-third, &c., tuned at these intervals above I.
VIII. Flute; metal and wood mouth-pipes, (more ge-
nerally wood,) in unison with IV. IX. Trumpel (marked
T); reed-pipes, of metal, in unison with I. X. Clarion
or octave trumpet stop; metal reed-pipes, tuned an
octave higher than IX. XI. Bassoon,- reed-pipes, in
unison as far as their compass reaches with I. XII.
fiemoua, or krum-izoru ,- reed-pipes, in unison with I.
XIII. Oboe; reed-pipes, in unison with I. XIV. Vom-
lzumema ; reed‘pipes, in unison with I.
Among the compound stops are, I. The sesguz'allem.

348
ORGAN.
(marked Sq), consisting of 4: or 5 rows of open
mouth-pipes, at the ‘intervals of seventeenth, nine-
teenth, twenty-second, twenty-fourth, or twenty-sixth
above the open diapason. IL The corner‘, a stopped
diapason, principal, twelfth, fifteenth, and seventeenth;
but this is now altogether gone out of use in'England.
III. Mia'lui'e or furnilure stop, r, consisting of several
ranks of pipes nearly the same as those of the ses-
quialtera, but some of higher pitch. .
The different series of stops are so distributed in
a large organ as to form three or four separate organs,
each of which has a distinct row of finger keys, its
own separate wind-trunk, wind-chest, sound-board,
&0. And these three or four distinct organs com-
prised in one, have been recognised as such by having
different names assigned to them; thus we have the
great organ, the choir organ, and the swell; to which
may be also added the pealal organ, or fool keys for
acting on the larger pipes. The most important of
the three key-boards is that of the great organ :
it contains the principal stops for giving power;
and is generally the lowest but one. The compass
is 4: or 4% octaves, beginning with o (8 feet) as the
lowest note. In French organs the principal reed-
stops, and some others of considerable power, are
made into a separate organ, which receives a different
pressure of wind. Its key-board, called the clauz'er
ale bomlarcle, is immediately above that of the prana’e
argue. The lowest row of keys generally belongs
to the posiz‘if or c/zoir organ. It contains stops of a
light character, and solo stops. The great organ is
situated the forepart of the case, in order that its
largest pipes may be planted in the ornamental front,
and that it may have a louder effect. The choir
organ is sometimes placed in front of the great organ
in a separate case at the back of the player, and is
hence sometimes_ called the chair organ. The upper
row of keys belongs to an organ called the swell. It
consists of an organ shut up in a box closed on 3
sides and having in front Venetian shutters, or move-
able louvre boards, arranged so as to open and shut by
means of a pedal. When shut, the sound appears to
be muflied and distant, but on being gradually opened,
the sound becomes louder. In this way, the effect
of crescendo and diminuendo is produced. The
swell contains the same kind of stops as the great
organ, but on a smaller scale. Stopped pipes are
used for the lower notes for economyof space. The
pedal organ, played by the feet, consists of 32-fcet
stops, with 16-feet stops, 8-feet stops, and smaller
sizes. There is not always, or, indeed, often a sepa-
rate pedal organ, the pedals being used for the larger
pipes of the great organ called pea’al pipes (16-feet).
In. Messrs. Ducei’s organ in the Exhibition, the
pedal notes, 12 in number, beginning with Iii-feet o,
aresaid to have been all produced from one pipe
about 4: feet-long, contained in the stool on which
the organist sat. It is stated that the makers have
F‘ found a means of so varying the proportions and
make, as to ‘cause a stopped pipe of 41 feet long to
sound a 16-feet note, of 8 feet, a 32-feet note, of
2feet, an 8-feet, note, and so on; and, secondly,

they have made the same pipe speak different notes,
by opening holes situated at certain distances in one
of its sides, on the principle of the flute and other
orchestral wind instruments. By applying, therefore,
the pedal keys to move valves covering these holes,
the whole range of an octave of pedal notes is pro-
duced by a simple and inexpensive means.
We have said that the bellows communicate by
means of channels or wind trunks with certain winal
e/iesls, or reservoirs, and supply them with air:
these wind chests distribute the wind to the various
pipes when the finger or .foot keys (manuals and
pedals) are pressed down. With respect to the
bellows, they may be single or cloulle, the former
being commonly used in church organs, and the latter
in chamber organs. Single bellows consist of two
oblong boards 6 b’, b " 6'”, Fig. 1553; connected at l)’
_u by a joint of leather, and at the
“Uri-l other 3 .sides by thin folds of wood
joined together with leather. The
lower board is fixed, the upper move-


Fig. 1553.
able. In the lower board, at u u, is a hole, covered
with a valve or pallet, opening inwards. At 0 is
another aperture leading into a hollow box, 0 b'”,
furnished with another pallet opening outwards.
This box communicates with the wind trunk. When
the upper board is raised by pressing down the
lever l l’, the air rushes mat the aperture 22 v, and on
letting go the lever the pressure of the weights 011
the upper board forces the air into the wind trunk
at b'”, the pallet at p preventing the return of the
wind from the wind trunk when the upper board is
raised. In order to keep up a constant supply of
wind 2 or even 3 pairs of bellows are required: some
of the large organs on the continent have as many as
12 pairs. This diagonal form of bellows is quite
abolished in England.
Double bellows are made with 3 boards, ab, Fig.
1554, the riser, m b’ the middle, and f 6" the feeder
boards. The air passes in at the valve 0 in the
feeder. In the middle board at p is the pallet of com-
".3 llll lu-nlunlnmuuunu

____—___§
._.__-_-________ ..
7}‘) n "—;-;%'\“A\\\\“ sam“\\\y\m\mm l ..~
:— _ _V;_,__ _..__.=_~_=-~ w.“ A -
,__..-—.L. . .._I _._~\ ‘ »~~_~r.
X‘L\\\\\\.\\~f \ ___.





Q1.
munication, and at w in the riser is the waste pallet,
which opens when the bellows are sufficiently full.
The riser discharges air into the wind trunk at an.
The weight laid on the reservoir determines the
pressure of wind, which is usually equal to that of
a column of water about 3 inches high, 'or 15lbs. per


ORGAN. ‘ .
349
square foot. It is' now common to use different pres-
_ sures of wind to different parts of the same organ,
separate bellows being used for each pressure. In
some of the organs in Germany the organ blower
does not work the bellows levers, which project from
the frame of the organ, by manual labour, but by
stepping upon them one at a time as each lever rises,
and allowing the weight of his body to bring it down,
and so raise the bellows. In the Great Exhibition, in
the bellows to the organs exhibited by Messrs Ducci of
Florence, the feeder, consisting of a moveable board be-
tween two fixed ones, was double-acting; that is it sup~
plied wind by its upward as well as downward motion.
Mr. Bishop, the celebrated English organ builder,
(who has kindly conducted us through his workshops
and explained to us the structure of various organs in
progress of building, as well as in the finished state,)
has introduced a variety of small but valuable im-
provements in the construction of organ bellows.
Mr. Cumming, of Pentonville, has also invented
what is called the compensation fold. It is evident,
S. D

Fig. 1555.
number of grooves, each containing a thin bar of
wood, thus dividing the box into parallel channels
completely separated from each other. The number
of channels corresponds with that of the finger-keys,
and as there are 12 keys in each octave the number
of channels is 12 multiplied by the number of octaves
in the key board. Holes corresponding with the
number of ranks of pipes are bored through the upper
side of the sound board into each channel. The
under side of the sound board is covered with parch-





ment or leather, 2, Fig. 1555, and LT, Fig. 1556,
except a space along the fore part, which is covered
by the wind chest, and where each channel is closed by

SECTION OF SOUND BOARD, WIND CHEST, 8Z0.

that when the bellows is falling under a certain
load or weight of wind, and driving the air into
the trunks, the collapsing of the folds of the bellows
will diminish the capacity by a certain quantity-
plus that due to the falling together of the top and
bottom boards, and thus lead to irregularities of
pressure which disturb the estimate as to the weight
required on the top board. The compensation fold
offers an ingenious remedy for this defect. In
this contrivance the folds of the bellows are so
arranged, that while one fold collapses inwards the
other fold collapses outwards, thus exactly neutra-
lising the loss of capacity arising from the folds.
The bellows supply the wind chest W C, Fig. 1555,
with condensed air. To the upper part of the wind
chest is attached the sound board $13 (as it is not‘
very correctly called, for the pipes, not the sound
board, produce the sound). The sound board is an‘
oblong frame or box, the upper side of which is
formed of stout board. On the under side of this
board, in the direction from front to back, are a
59
P.
a valve or pallet v v, Fig. 1555, and 22p, Fig. 1556,
hinged at '0, and pressed down to the groove by
means of a spring 5, Fig. 1555. The wind chest,
which thus receives all the valves, is an air—tight box,
so that the wind which is poured into it from the‘
bellows through the wind trunks has no exit except
through the channels of the sound board when the
valves which cover them are raised.‘ Each valve
opens downwards and is connected with the key
movement by a small brass wire hook, or pull-(loam,
PD, Fig. 1555, which passes through a perforation
in a brass plate upon the bottom of the wind chest.
On the upper side of the sound board, and in a.
direction at right angles to the channels above de-
scribed, is another set of grooves, formed by screwing
down thin pieces of hard wood, called éearers .- the
number of these grooves corresponds with that of
the stops or sets of pipes. Fig.1557 represents a
portion of the upper surface of the sound board,
divided into 4: longitudinal grooves by the bearers
:e B. In these grooves holes are bored through the
top of the sound board, one into each channel below.
The holes shown in the strip s s are in two lines for
350‘
ORGAN}
the purpose of obtaining a greater distance bet-wee
the holes of two adjoining channels, and also to
guard against a defect called “ the running of the
wind,” which will be explained presently. The holes


Fig. 1557.
diminish in size according to the size of the pipes.
Over each groove or range of holes lies a register
or slide nn, made of mahogany or wainscot, a little
thinner than the bearers, but exactly fitting the
groove. It is pierced with holes corresponding with
those in the sound board, Fig. 1555, and it is evident
that by drawing the slide a little towards one end,
all the holes of the sound board will be covered, and
the row of pipes placed over them will receive no
wind. In some convenient part of the slide'is a
small slit, which receives a strong iron pin fixed in
the sound board, whereby the exact degree of motion
is allowed the slide for shutting or opening the
holes. The slip or groove in which the slide runs,
and the slide itself, are polished with black-lead for
the sake of smoothness of motion. The wind is apt
to run along under the slide, and to blow into a dif-
ferent hole to that intended, consequently causing
the wrong pipe to speak, or rather to squeak. This
running of’ the wind may be prevented by cutting
small grooves in the top of the sound board, running
in a zigzag line between the holes, as shown at s s,
Fig. 1557 : these channels conduct the superfluous
wind out at the end of the slip, and thus remedy
the evil. '
Over the bearers and slides lie the upper or stool:
boards, s s 13, Fig. 1555, in which the pipes are planted
in holes bored for the‘ purpose, corresponding of
course with the holes in the sliders and sound board.
The upper part of the feet of the 'pipes is sup-
ported by moles or thin boards an mounted on small
pillars. The upper boards are screwed to the bearers
as closely as possible, with only just sufiicient space
to allow the registers to slide. In the case, how—
ever,_ of the larger stops, the pipes occupy so much
space that they cannot stand immediately over the
grooves which supply them with air: they are planted
in any convenient positions within or even outside
the case, and wind is conveyed to them by means of
grooves cut in the upper board leading from the
holes “which would otherwise. be occupied by the
pipe, to within an inch or. so of the place where the
pipe actually: stands: the groove is then discontinued-
and a'hole'is‘ bored. When all the grooves are cut
in the upper board, the surface is covered with parch-
ment, which thus converts the open grooves into
closed channels for the passage of the wind, which
channels are opénonly at’ the hole on the under side,

communicating with the sound board through the
slider, and at the other hole into which the foot of the
pipe is inserted.
The connexion between the finger key and the
pipe will be more clearly understood by referring to
Fig. 1558, in which f is the finger key moving on a
centre pin 0; r a
small rod of wood
called a sticker, the
lower end of which
rests on the distant
end of the finger
key: the upper end
of the sticker is
attached by a pin‘
to the end of the
lever l l, which
moves on a centre
at c’. To the oppo-
site extremity of T
f,-==§*———_______:rf’_'—‘___-%ilk
l
this lever is attached a wire to, which passes air-
tight through a brass plate at the bottom of the
sound board, and the upper end of the wire is at-
tached to the valve at 22. Now when the finger key
is pressed down, the opposite end of the key raises
the sticker, which in its turn raises the end of the
lever l, and lowers the opposite end, which draws down
the valve o by the wire 20. When the finger of the
performer is removed the spring s closes the valve,
and causes the lever, sticker, and key, aided, how—
ever, by their own weight, to fall into their original
position. _
The above arrangement, however, supposes the
finger key to be opposite to the valve intended to be
opened, a condition which evidently cannot apply to
by far the larger number of pipes ; for the key board
4
11;“


I' ,____-
l
I I MMJ'QBRTQF -,-______-,
I
' Wamwfiefia
H
Fig. 1558.


\ is not more than 3 feet in width, even in the largest
organ, while the sound board extends along nearly
the whole width of the front. By means of a little
more machinery the finger key is easily connected
with the valve which it is intended to open. In Fig.
1559, ff are the finger keys, 8 s the sticker, and ll the
levers, as before; rr' 7'?" are rollers moving on their
axes 5 w rods or wires attached to the ends of levers
and to arms in the rollers towards the ends 9‘; w’ w’
are wires from the valves vv, attached to the arms on
the same side of the rollers towards their distant ends
r’. It will be seen by this arrangement that by
pressing the finger keys the valves will be opened as
before.
In the large organ exhibited by Mr. Willis in the
Great Exhibition, various ingenious mechanical novel-
ties were introduced, among which may be mentioned
the valve for admitting'wind to the pipes in the pedal
organ. It is formed by covering the aperture with a
piece of leather fixed at one end, and attached at the.
other end to a wooden roller.
When this‘ roller is‘
. moved by a wire attached-to the pedal key, it wraps
ORGAN‘.
351
the leather round it and ‘thus uncovers the opening;
when the key is released, a spring brings the roller
back, and by unrolling the leather again covers the
aperture. ' _
The key movement, represented in Fig. 1559,
is called the longmovement. because it may be eX-
tended to an almost indefinite length. It was used





being very unequal, varying from a few' hundreds to
many thousand cubic feet' per second, very different
degrees of elastic force are produced in the air. The
more elastic the air, the more readily the pipes speak,
and the purer is the tone. When the expenditure of
wind is small, the elasticity is greater than when it is
large, and the pressure of highly elastic air against
the valves renders them more difficult
to open than when the air is only



————————W moderatel com ressed. The d‘ .-
». .. y -P lfi
W- _ culty of opening the valves under
_ l§§%7:§“§%'—§Em strong pressure was attempted to






Fig. 1559.
for the organ at the commemoration of Handel in
Westminster Abbey, when the keys were 23 feet
from the organ, and 19 feet below the level of the
common key frames. The construction will be assisted
by observing the common method of hanging bells,
the trackers in the organ being of wood instead of
wire. In the organ at S. Alessandro in Colonna, at
Bergamo,.built by Serassi in 1782, there are about
1.00 stops, and 4! rows of keys: the first and second
belong to the great organ and choir organ: the third
is connected .by mechanism, which passes _under-
ground to a distance of 115 feet, with a third great
organ in another part of the church directly opposite
the first. Notwithstanding the distance from the
keys, the third organ obeys them as readily as the
first. In Roman Catholic countries all the claviers
are frequently fixed in a detached upright console, so
that the player sits with his back turned to the in-
strument, thus enabling him to watch the service of
the church and introduce the proper music at the
proper times.
The organ, as usually constructed, requires not
only consummate skill on the part of the performer,
but also considerable strength both of hand and foot.
It is stated that the organist at Haarlem is obliged to
strip like a blacksmith for his usual hour’s perform-
ance, and that at the end of it he retires covered with
perspiration. Besides this, the expenditure of wind
535%
7 n
MTTl—mfi—HHHHH iii—“Tn \‘ _

be remedied by diminishing the
quantity of wind or the dimensions
“l I of the larger pipes, by making the
¥ . l.’ openings for the valves smaller, and
g ' f’ bringing fewer stops into play at one
time. These contrivances, however,
injured the character of the organ, and put a limit
to its size. At length a remedy was found by
Mr. Barker, a native of Bath, in the beautiful and
simple invention known as the pueumalz'e lever, in
which the elasticity of the air itself is made to over-
come the resistances which were formerly thrown
upon the organist. It is true that in this arrange-
ment more work is thrown upon the bellows-blower;
but no one would object to relieve skill at the ex?—
pense of labour. .-
=1
0
The construction of the pneumatic lever will be-
understood by referring to Fig. 15 60, in which w c is
the interior of the wind-chest; u the valve, and s the
spring for keeping it closed ; p (Z the pull-down; l a
lever, to which is attached the rod 7‘ connected with
the finger-key apparatus. Through the .valve o passes
a screw wire 20, terminating in a ring at the lower
part, and furnished with a small button of leatherwat
the top. 0 is the wind-channel, closed below by a
skin of leather or parchment, as already explained;
The top is partly closed by a small pair of bellows B,
the bottom of which communicates by a slit with the




Pm i’ I, I,
\ <Y\Y\\\\\§\Y\l\“\<\\<\\\l@AW \\\\\\ \\\\\\\\\\ ‘mum ,, 3
. I’ :m






\\\\\\\\\
channel 0. The other portion of the top of the wind;
chest is closed by a board 5 a’, fitting into grooves, so
that by drawing forward the part: 6' it can be with-
drawn together with the swing valve attached to it
below. This valve 12' moves upon a pin attached to a
saddle-piece 12. On the tail of the valve is a small
leaden counterweight e, which causes the valve to close
the opening 0 when the supporting button at the end
of the wire 20 is drawn down. In its ordinary position
this valve is kept half open by means of this button;
The bellows B has a projecting piece or tail 5, to which
is attached a rod r’ communicating with the valves,
coupling-movements, 8:0. which have to be moved;
352
ORGAN.
The action is as follows: on depressing the finger-
key which corresponds with the rod r, the. lever l
opens the valve 2) by means of the’ pull-down p cl ;
at the same time the valve 0’, not being supported by
the button on ie, falls upon the opening 0 and closes
it. The air, strongly condensed in the wind-chest,
rushes with great force into the channel 0, and also
into the bellows B, which are instantly inflated, and
in rising overcome all the resistances which act on
the rod r’. .So long as the finger continues to press
down the key, the air ‘remains compressed in, the
bellows, and .keeps them inflated ; but as soon as the
finger is removed, the 'valve 12 rises, and by means of
the wire 20 presses the tail of the .valve 0', which it
half opens, and allows the condensed air to escape from
o and 13.. The rapidity and precision with which all
this. is done are surprising: .the bellows 13 rise and
fall simultaneously with the motion of the fingerakey,
and. the ‘notes may be repeated with equal facility.
The bellows B vary in size with the resistances to be
overcome, but they are usually not more than a few
inches in length and breadth. The pneumatic lever
is supplied with air by a special bellows, which com—
presses it much more highly than the ordinary
bellows which supply the.pipes with wind. -
Our limits will not allow. us to detail various other
mechanical contrivances which add, to the efficiency
of the organ; but a few may be just alluded‘to. - By
means of certain movements 'called couplers, made‘ to
act by draw-stops in front of the instrument, or by
pedals, different sets :of [reg/s may be made to act
together, so as to give additional power and variety.
Thus the great organ maybe coupled with the choir
and the swell, or the key-boards may be united in
pairs; or one key may be coupled with another, so
as to sound its octave above or. below. In Italy this
kind of mechanism is called the'ierzo inane, or third
hand. '
We must also notice Mr. Bishop’s admirable compo-
sie‘ionpeclals for opening and shutting the stops by the
foot, so that the hands need not be removed from the
key—board. A series of pedals is arranged above the
usual pedals, and to each pedal corresponds a certain
combination or composition of stops, so that on
pressing down the pedal, the required stops are
drawn, and at the same time push in those which do
not belong to its own combination.
Mr. Bishop is also the inventor of an anti-concussion
apparatus, for preventing the pulsation or concussion
of air in the wind-chest when a_ large number of .pipes
are suddenly made to cease speaking, and a few only
held on. It consists of a small reservoir connected
with the wind~trunk, held down by a spring of ;,suffi;
cient“ force to balance the ordinary pressure of wind.‘
When the rush of wind to a large number of pipes,
is suddenly ‘checked, this spring yields, and allows
the. escape of a portion of the condensed air, which
would otherwise expend its force on the pipes which
are speaking.
We cannot conclude this imperfect notice without
referring to the larrel organ. This contains the parts
of finger organs, with the addition of , a . cylinder or
bellows to the pipes.

barrel revolving on pivots instead of the key-board.
The tunes to be played. are set 011 the surface
of the barrel by means of wires, pins, and staples.
These, by the equable revolution of the barrel, act
upon levers, and give admission to the wind from the
The same action of the hand
which . turns the barrel, supplies wind by giving
motion to the bellows. Fig. 1561 is the
section of a small barrel organ, in which
_0 is the barrel or cylinder, on the axis
of which is fixed a"toothed wheel w, in
the teeth of which a‘screw on the axle A,
turned by the handle H, works, and thus
causes the barrel to revolve. The pegs,




ll.
ii ' ll l
\ mun llllllllllllllllllllll‘lll
,n.



lllllllllll
'1 {If} j
11% - -. 3%‘!
~ I I 1 f.',_ c _ .-
__.__ )1 II IIIIIIIJJ 1:111”
~lllllllllll l lllll ll lllllllll llllllllll lllllllllllllll llllll
Fig. 1561.
&c. are shown on the surface of the barrel, one of
which keeps up the lever ll’, which moves on the
axis a.
sticker s, which, by a wire passing into the wind-
chest, opens the valve 12. “Suppose on this barrel
an air of 32 bars were to be set, and conceive
the circumference of the circle divided into so many
equal=parts, these parts will represent the bars or
measures of the air; and being occupied with the
due proportion of pegs and blanks under the‘ proper
levers, will, by the turning of the cylinder, make the
proper pipes speak at their right times. As the levers
for opening the valves are at a considerable distance
apart, and thejpegs occupy very little space, there is
room for several airs being set on the same barrel.
Thisbeing pushed a little way towards one side, till
the .pegs' of. another tune are brought under the
levers, is there fixed by means of a sliding bolt, which
falls into a._no'tch in a piece of brass fixed to the
frame ‘in which the barrel runs. When pieces of
music’ are to be set on a barrel longer than one revo-
lution could afford space for, the end of the axle of
the cylinder is formed into a screw, which works on-
a fixed pin, and consequently draws the barrel hori-
zontally while turning round its axis“ The pegs are
The end l’ of the lever pushes down the-
OSMIUM—OXALIC ACID.
353
then disposed in spiral lines round the surface, so that
those of the first revolution are clear of the levers’
when those of the second come to them. Thus as
many revolutions are obtained as are necessary.”
ORPIMENT. See Ansnnrc.
OSCILLATION. See CENTRE.
OSIER. See BASKET.
OSMIUM (Os 100), a rare metal contained in the
ore of platinum, and named from the acrid poisonous
smell (do-p1), odour) of its peroxide. The metal, in its
most compact state, has a bluish-white colour: it is
somewhat flexible in thin plates, but is easily reduced
to powder. Its sp. gr. is 10. It is neither fusible
nor volatile. When heated to redness it burns, and
forms the peroxide or Osmz'c acz'd, OsOa, which is vola-
tile. There are 4 other compounds with oxygen, viz.
OsO, the prolorm'de; 0s203, the sesqnz'oan'de; 0502, the
binom'de, and OsOs, Osmz'oas acid; the last exists only
in combination with alkaline bases. Osmium has not
been applied to any use in the arts.
OXALIC ACID (0203, HO+2HO) occurs ready
formed' in. several plants in combination with potash
as an acid salt, or with lime, such as the Oa'alz's aceto-
sella or wood sorrel, the Ramea: acelosa or common
sorrel, the varieties of r/zubarb and other plants. In
some parts of Suabia it is prepared from the ramen :
the plant is piled up in a rude kind of lever press,
and the juice expressed: what remains inthe press is
sprinkled with water, and pressed a second time.
The juice thus obtained is clarified by being mixed up
with a white argillaceous earth, and the clear liquor
being decanted off is crystallized by evaporation. The
crystals consist of binoxalate and quadroxalate of
potash, known in commerce as salt‘ of sorrel. The
oxalic acid is obtained by adding acetate of lead to a
solution of the salt of sorrel : oxalate of lead is thrown
down, which is decomposed by the proper quantity
of sulphuric acid: the liquor, on being evaporated,
yields crystals of oxalic acid.
The commercial demand for oxalic acid is chiefly
supplied by forming it artificially by the action of
nitric acid on sugar, treacle, and dextrine. 1 part
of sugar is heated gently in a retort with 5 parts
nitric acid of sp. gr. 1'42 diluted with twice its
weight of water: the acid is rapidly decomposed with
copious red fumes, and the sugar is oxidized. As
the action slackens heat is' again applied, and the
liquid concentrated by distilling off the superfluous
nitric acid until it deposits crystals on cooling.
“ These are drained, redissolved in a small quantity
of hot water, and the solution set aside to cool. The
acid separates from a hot solution in colourless
transparent crystals derived from an oblique rhombie
prism, which contain 3 equivalents of water, 1 of
these being basic and inseparable, except by substi-
tution; the other 2 may be expelled by a very gentle
heat, the crystals crumbling down to a soft white
powder, which may be sublimed in great measure
without decomposition. The crystallized acid, on the
contrary, is decomposed by a high temperature into
carbonic and formic acids, and carbonic oxide, without
solid residue.”—-Fozones.
YOL. II .

In the manufacture of oxalic acid on the large
scale, use is also made of the saccharine substance
formed by the action of sulphuric acid on potato or
other starch (as in Nyren’s process). For this pur-
pose, the potatoes are well washed, and reduced to a
fine pulp by rasping and grinding. The pulp is then
washed a few times by well stirring it in water: and
being allowed to subside, the water is run off. The
pulp is next transferred to a vessel lined with lead, with
as much water as will allow of the mixture being boiled
freely, by means of steam pipes of lead. To the mix-
ture of pulp and water, about 2 per cent. by weight
(of the potatoes employed) of sulphuric acid is stirred
in: this is at the rate of from 8 to 10 per cent. of acid
on the quantity of farina contained in the potatoes.
The whole is boiled for some hours, until the pulp of
the potatoes is converted into saccharine matter.
The completion of the process is ascertained by a
drop of tincture of iodine to a small quantity of
boiling liquor placed on the surface of a piece of
glass : if any farina remain unconverted a purple
colour will be produced. The saccharine product
thus obtained is filtered through a horse-hair cloth,
and carefully evaporated, until a gallon of it weighs
about 14¢ or 141% lbs. It is now in a proper condition
to be employed in the manufacture of oxalic acid, by
the application of nitric acid as when sugar or treacle
is used: a portion of the oxygen of the nitric acid is
substituted for the hydrogen of the sugar, oxalic acid
being formed, and binoxide of nitrogen evolved from
the liquor.
Horse-chestnuts deprived of their outer shells may
be used instead of potatoes in this manufacture :
they are treated in the same way. Instead of the
sulphuric acid, the same proportion of diastase may
be used ; in which case, the liquor is made of the re-
quired strength at once, and filtration and evaporation
are not required.
The apparatus used in the conversion of the sac
charine matter into oxalic acid consists usually of
earthenware jars, of about 2 gallons’ capacity, which,
when charged with nitric acid and saccharine matter,
are placed in water baths capable of holding 100 or
more of these jars. These baths are of brick, lined with
lead, and are heated by steam coils of lead. Instead
of jars, vessels of lead, or of wood lined with lead
may be used: 8 feet square and 3 feet ‘deep is a good
size, and a coil of 418 feet of 1 inch pipe gives the
required heat—about 125° Fahr. The strength of
the nitric acid should be fi'om 1200 to 1270. While
the operation is in progress, the active evolution of
gas with the appearance of red fumes, and a peculiar
smell, are signs of good working condition. The
judicious addition of sulphuric acid increases the pro-
duct of oxalic acid.
The product of oxalic acid from sugar has been un-
derstated by chemical writers, probably from the fact,
that by boiling the sugar with strong nitric acid, a
large portion of oxalic acid becomes converted as soon
as formed into carbonic acid, and is lost. Thus, it is
stated, that 100 lbs. of good sugar yield 50 or 60 lbs.
of oxalic acid; whereas the manufacturer will obtain
a a
354:
OXALIC ACID—OXYGEN.
from 125 to 130 lbs. from that quantity. 100 lbs. of
average treacle yield 105 to 110 lbs. of oxalic acid.
The mother liquor having been poured of, the
crystals of oxalic acid are thrown on drainers and
washed. The mother liquor is treated with a fresh
supply of nitric acid and treacle for another opera-
tion.
Other methods have been described for the manu—
facture of oxalic acid,1 but the low prices of treacle
and sugar are in favour of their direct use in this
manufacture. Methods have also been contrived for
employing the evolved vapours in the manufacture of
nitric acid. For example, in Messrs. McDougall and
Rawson’s patent process, a series of vessels contain-
ing water are used, into the first of which the nitrous
gas or fumes are passed through a tube dipping below
the surface: air is also admitted, which mixes with
the gas bubbling up through the water. Attached
to the last vessel of the series is a pneumatic ap-
paratus, by means of which the mixture of nitrous
gas and air is drawn through this series of vessels,
each containing a tube dipping into the liquid, and
another tube attached to its top to connect it with the
next vessel. The nitrous gas thus passing alternately
into air and water becomes converted into nitric acid.
Ecarnot has patented a process for recovering the
nitric acid : the regenerating vessels are filled with a
porous substance such as pumice-stone; oxygen is
supplied by a blowing machine, and a flow of steam
is brought from a boiler. In this, as in Jullion’s pro~
cess, the following is the ' theory of action :--The
oxides of nitrogen evolved from the liquor in the
decomposing vessel coming in contact with oxygen are
converted into hyponitrous and nitrous acids, which,
on being mingled with steam, are decomposed into
nitric acid, and binoxide of nitrogen. The use of
steam may be obviated by using heated air or oxygen
in the decomposing vessels, in which case the moisture
will be furnished from the liquor, and the amount of
mother liquor be diminished. The compounds thus
formed, when passed through suitable condensers, will,
if the supply of air or of oxygen has been in excess,
be all or nearly all condensed into nitric acid.
The crystals of oxalic acid are soluble in 8 parts of
water at 60°, and in their own weight or less of hot
water. The solution is intensely sour and highly
poisonous. Many accidents have occurred from the
resemblance of the crystals of oxalic acid to those of ‘
sulphate of magnesia (Epsom salts), which has led to
the careless dispensing of the one for the other. The
intense sourness of oxalic acid, and the saline bitter-
ness of Epsom salts, readily distinguish them. The
remediesin cases of poisoning with the acid, are chalk
or whiting, magnesia or its carbonate, or copious
draughts of soap and water. One of these should be
immediately resorted to.
The chief demand for oxalic acid is in calico-print-
ing, where it is used as a discharger. [See CALICO
PRINTINGJ It is also employed by straw and Leghorn
bonnet makers for the purpose of cleaning their wares.
It’ is'also used for cleaning boot-tops.
(1) See Pharmaceutical Journal for March, 1852.


The salts formed with oxalic acid are called oaalatcs.
Oxalate Qf'potaslz is sold under the name of “Essen-
tial Salt of Lemons” for the purpose of discharging
iron-moulds from linen. The iron of the ink attaches
itself firmly to the fibre of the linen: but as the iron
is soluble in a solution of oxalic acid, it quits the
linen and forms an oxalate of iron.
OXYGEN (08). This important element is widely
diffused throughout nature, but is never met with
in a pure or isolated form. In the atmosphere it is
mechanically mixed with nitrogen; in water it is
chemically combined with hydrogen. It combines
with nearly all the other simple substances, and forms
with them an immense number of compounds. When
we wish to obtain nitrogen for the purposes of expe-
riment, all that is necessary is, to place in a confined
portion of atmospheric air some substance such as
will absorb the oxygen and leave the nitrogen free.
The converse of this process cannot be adopted, since
we are not acquainted with any substance capable of
absorbing nitrogen and leaving the oxygen. There
are, however, many solid bodies containing oxygen,
which, on being subjected to a high temperature,
evolve it in a gaseous form. Such are the red oxide of
mercury [see MEncURY], the black oxide of manganese
[see MANGANESE], or chlorate of potash. The first
may be distilled in a glass tube, and requires only the
moderate heat of a spirit-lamp: the second must be
raised to a bright red heat in an iron gas bottle, or it
may be mixed with sulphuric acid and distilled in a
glass flask or retort: the third requires a high tem-
perature in a retort made of glass containing no lead :
but it is remarkable, that the presence of a little
black oxide of manganese in powder, or of oxide of
copper, allows the operation to be conducted much
more rapidly, and at a much lower temperature. At
between 450° and 5000 the mixture begins to give
off oxygen, being nearly 2000 below the fusing point
of the-chlorate. A proportion of i of oxide of man-
ganese is quite effectual. The action of the metallic
oxides has not been explained, except by vaguely
referring it to catalysts, or that kind of combination
or decomposition which takes place from the presence
or contact of a body which is, as it were, the medium
or cause of changes in which it does not itself neces-
sarily partake. It seems natural to regard this ex-
ample of it as a mere effect of heat, the particles of man-
ganese or of copper acting as an assemblage of foci
upon the powdered chlorate of potash with which they
are in contact; but in such case, any powder would
have the same effect provided it were not readily com-
bustible in oxygen, and not liable to change in the pre-
sence of the potash salt. It appears, however, that
sand, powdered glass, &c., has little or no effect.
Professor Miller, of King’s College, London, has,
at the request of the Editor, kindly undertaken a few
experiments on this subject. The results are as
follows :—When the chlorate of potash is mixed with
peroxide of manganese, peroxide of iron, peroxide of
lead, or oxide‘ of copper, the gas is developed at least
100° below the fusing point of the salt. The metals,
manganese, iron, lead, and copper, form (with the ex-
OXY GEN -—PAIN TIN G.
355
ception of the last) oxides of an acid character, which
are very unstable and readily part with their excess
of oxygen. Powdered glass and sand produce an ex-
trication of gas after the salt has fused, but at a
lower temperature than with the pure salt. Oxide of’
zinc produces no effect; nor does magnesia. These
oxides are the only known oxides of the metals which
yield them. The general conclusion appears to be,
that metals which are capable of forming peroxides,
readily decomposable by heat, favour the decomposi-
tion of chlorate of potash at a low temperature;
while the oxides of those metals which are not
capable of forming peroxides, do not favour the de-
composition.
For the methods of collecting gases at the pneu-
matic trough, and for experimenting with them, we
must refer to chemical works.
Pure oxygen gas is without taste, colour, or odour:
it has not been reduced to the liquid form under
great pressure and intense cold. It is a little heavier
than its own bulk of atmospheric air, its sp. gr. being
110%. It is 16 times heavier than its own bulk of
hydrogen. 100 cubic inches of it at mean temperature
and pressure weigh 341'109 grains. It is evolved at
the positive electrode or anode, and is therefore placed
among the '_electro-negative bodies or anions. It is
scarcely soluble in water, nor does it alter the colour
of litmus or render lime-water turbid. It is the grand
supporter of life (whence it is sometimes called uz'lul
air), and also of combustion; and in illustrating its
powers as a supporter of combustion, the chemist dis-
plays some of his most striking and beautiful experi-
ments. A match of wood, with only a spark of fire
upon it, or a taper, with only a red-hot wick, on being
plunged into this gas, bursts into brilliant flame. Sul-
phur, charcoal, phosphorus, iron wire, &c., on being
ignited and plunged into this gas, burn vividly. See
CoMBusrIon—CANn'Ln—HnAr—FUEL.
The compounds formed by the direct union of
oxygen with other bodies, are called oxides. Some of
these are ullealz'ue or basic, such as potash, soda, oxide
of silver or of lead. Others have directly opposite pro-
perties, and are acid, such as sulphuric acid, phos-
phoric acid, 850.: they unite with the basic oxides
and form salts. A third group is termed rzeulrul
oxides, from not readily entering into combination:
black oxide of manganese is an example. See
ArrInIrr—Aromc THEORY.
Oxygen was discovered by Dr. Priestley in 17741,
and about the same time by Scheele in Sweden and
Lavoisier in France. The term oxygen was given to
it by Lavoisier, from 6559, acid, and yew/rice, to pro-
duce, on the supposition that by combining with other
bodies, such as sulphur, phosphorus, &c., it formed
acids ; but we have seen that it may produce alkalies
or substances which are quite neutral. There are
also acids which contain no oxygen. [See Hrnno-
cHLonIc Acrn] Theterm principle qfacz'dz'ly, as applied
to oxygen, has long been abandoned, for it is now ad-
mitted that the properties sour, sweet‘, bitter, &c., are
not ultimate properties capable of being referred to
any principle, but simply the result of new molecular

arrangements which are capable of affecting differently
our organs of taste. Thus the solutions of nitrate of
silver and hyposulphite of soda have a nauseous bitter
taste, but if they be mixed together they produce an
intensely sweet taste. The word oxygen is too deeply
rootedin scientific nomenclature to be safely removed,
but it may be taken as a remarkable instance of an
abiding word which changed its original meaning
within a comparatively short period after its intro-
duction.
PADDLE-WHEELS. See STEAM NAVIGATION.
PACKING-PRESS, a term sometimes applied to
the hydrostatic press when used for packing goods.
See Hrnnosrxrrcs and HYDRODYNAMICS.
PAINTING. The mechanical processes concerned
in painting, as a fine art, require so much skill, that
a notice of them would be of little use to the general
reader. ENAMEL PAINTING has been described under
that head. HOUSE painting remains to be noticed.
This is the art of applying to the interior and exterior
of houses and other buildings a certain durable com-
position capable of preserving them from decay, of
keeping walls dry by preventing the absorption of
moisture, of rendering surfaces less liable to soil, and
capable of being easily cleaned. The decorative effect
is also not the least of the advantages of this art,
provided the painter exercise it with taste, according
to the principles developed by M. Ohevreul [see
LIGHT], and by Mr. Hay, himself a house-painter, in
his treatise “ on the-Laws of harmonious Colouring,
adapted to interior Decoration.”
Paint is a kind of paste, made by grinding white-
lead and linseed=oil. Other substances are used,
such as colouring matters or sluz'uers, as they are
called, drying materials or dryers, &c. ; but white-lead
is the basis of all ordinary paints, and forms at least
{lo-tbs of their composition. The laborious and
unwholesome operation of grinding paints with a
grinding-stone and muller, which was formerly done
by the painter, is now performed by the manufac~
turing chemist on a large scale in paint mills, which
resemble in many respects the mill described under
cbocolaz‘c. The linseed-oil is'sometimes boiled, which
gives it a greater facility in drying, but makes it
thick, so that it is only fit for outdoor work. Spirits
of turpentine, called lurps, are also much used.
Litharge and sugar of lead ground in oil into a thick
paste, are used as dryers. Japanner’s gold size is used
for the same purpose. Ochre, Venetian red, lamp-
black, Indian red, Turkey and English umber, terra de
Sienna, red-lead, Prussian blue, orange red, chrome
yellow, vermilion, and other pigments are used as
stainers.
Surfaces are prepared for painting by means of
sand-paper or pumice—stone, or by filling up with
putty, for the purpose of getting rid of inequalities.
Heads of nails are punched in, and stopped. Knots
in the wood, which would bulge out, or leave a stain,
are removed or cut out to the depth of % inch, and
pieces of the same wood inserted in their places,
glued in hand-tight only, for if compressed with a
hammer, they may afterwards swell and spoil the
A A 2
356
PAlNTINGé-PANTOGRAPH.
surface. For ordinary work, knots are merely
painted over with red lead and size.
In order to paint plaster, such as the walls of a
room or ball, properly, five coats are required. If the
plaster be not very absorbent, four will suffice. The
first consists of white lead diluted with linseed oil
to a thin consistency, with the addition of a small
quantity of litharge to ensure the drying. If the
plaster be guiele, the'oil is entirely absorbed, thereby
hardening the .plasterto the depth of if; inch. The
second coat is also thin, in order that the plaster may
be thoroughly saturated. This coat is only partially
absorbed. The third .coat is thicker, and contains a
little turps, and some of the colouring pigment, so as
to bring it near the tint required. The fourth coat
is as thick as it can be .used, equal parts of oil and
turps being employed. The colour is used several
shades darker than the finishing coat, and the dryer
is sugar of lead. The coats must be laid on carefully
and smoothly, each being rubbed lightly with sand-
paper before the next is applied. The finishing or‘
flailing coat, as it is termed, from its drying without
gloss, is of pure white lead diluted with spirits of tur-
pentine only, and is made a few shades lighter than
the pattern, since it darkens in drying. A small
portion of japanner’s gold size is used as the dryer.
The coat is applied as quickly as possible, since the
turps evaporates in little more than a minute after
being applied, leaving an indelible glossy surface.
The time which is to be allowed between the applica-
_ tion of the several coats, will depend on the weather,
the quantity of dryer employed, and the state of the
internal atmosphere.
between the putting on of the first two coats; a
somewhat longer time before the third is put on. The _
last coat before the flatting should not be left more
than two days, since much of the beauty and solidity
of the work depend on the latter drying into and
uniting with the former.
The absorption of moisture by the plaster of ceilings
may be prevented by applying two coats of paint, and
when dry and hard, a coat of tlislenzper colour; that
is, white lead ground in water and diluted with size
made from parings of white leather and parchment.
But in distemper painting it is very common to sub-
stitute whiting for white lead.
The painting of wood is similar to that of plaster,
each coat being thicker and smoother than the previous
one. In imitations of oak, marble, 850. there is a
groundwork of four or five coats, care being taken
that no brush-marks be left. The last coat, instead of
being flatted, is composedof equal parts of oil and turps.
The shades and grain of the wood are given by thin
glazings of Vandyke brown, terra de Sienna, or umber,
according to the kind of wood to be imitated. The
colours are ground in water and mixed with small‘
' beer, the tenacity of which is sufficient to prevent its.
rubbing off by the application of the varnish which
immediately follows. Wainscot is painted with a
thick substance, to receive the impressions of an ivory
or horn comb, with which the imitation of the grain
is produced. The varnish is copal. Imitations of
A few days should elapse’

marbles, &c. depend more on the taste and cultivation
of the painter than on mechanical skill; a remark
which applies to ornamental painting in general.
The painter works with hog’s-bristle brushes, of
various sizes. In laying on the colour, the brush
should be applied at right angles to the face of the
work, the ends of the hairs only touching it. The
paint is thus forced into the pores of the wood, and
equally distributed; whereas, if the brush be applied
obliquely, the paint will be left in thick masses where
it is first applied.
The'iconstant use of white lead renders painting an
unhealthy art; and it soon becomes fatally so if those
who exercise it are intemperate and uncleanly.1 It is,
however, satisfactory to reflect that the mechanic is
every day becoming a wiser and a happier man; he
prefers the coffee-shop and its instructive literature
to the gin-palace or the beer-shop and its degrading
results, and he has learned the important truth that
his health is one of the talents entrusted to his charge,
of which he will have one day to give account.
PALLADIUM, (Pd 541,) one of the metals found
in the ore of platinum. It resembles platinum in
colour, appearance, difliculty of fusion, and in being
very malleable and ductile. Its density is 118. It
is slowly attacked by nitric acid, but dissolves readily
in aqua regia. There are two oxides, PdO and Pd02.
Several alloys of palladium are known. The alloy
with iron is brittle, and in the proportion of 1 per
cent. it is said to improve the quality of steel for
certain cutting instruments. It destroys the colour
of gold: 1 part fused with 6 of gold forms a
white alloy, which, from its hardness and durability,
was employed for the graduated part of the mural
circle constructed by Troughton for the Greenwich
Observatory. Electro-plating with palladium is in
some cases useful, and is readily accomplished.
PALM OIL. See CANDLE—OILS AND FATS.
PANTOGRAPH, or Pmv'rxenxrn, an instrument
for copying drawings, either on the same scale as the
original, or in
any given pro-
portion to it,
larger or smaller.
It consists of 41
brass rulers, A B,
B0, 'n n, and n r,
Fig. 1562, the
two longer of
which, A B and
B c, are connect-
ed together, and
have a motion
round a centre
at B. The two
shorter rulers are
similarly connected at n, and with the longer rulers at
E and r; and being equal in length to the portions B n


Fig. 1562.

(1) Attempts have been made to substitute white zinc for white
lead in house-painting. The objections to its use are stated in our
Introductory Essay, 1). cxxxvi. For the mode of preparing white
lead, see Lnan, and for white zinc, see ZINC.
PANTO GRAPH—PAPER. 357
and Br, form with them an accurate parallelogram,
B F D E, in every position of the instrument. The in-
strument moves freely on ivory castors, which support
it parallel to the paper. The arms AB and E1) are
graduated, and marked %, —§—, 850., and have each a
sliding index, which can be fixed at any of the divi-
sions by a clamping screw. The sliding indices have
each a tube or sliding holder, with a pencil, a pen, or a
blunt tracing-point. The tube at 0 contains the
tracing-point; the tubes at G and A contain each a
pencil. A small cup is sometimes placed over the tube,
for containing sand or shot, in order to keep the pencil
down upon the paper when the instrument is in use;
but the pencil can at any moment be lifted off the
paper by means of a silken cord which passes from
the pencil round to the tracing-point at o, where the
draughtsman is situated, so that he can raise the
.pencil from the paper while he passes the tracer from
one part of the original to another, and he thus pre-
vents false lines being made on the copy. At A is a
flat leaden weight with a brass stem rising from it,
whichfits into any of the tubes. This weight has 3
or 4'! fine points on its under surface, to prevent it
from shifting on the paper; and under whichever
tube it is placed, it forms a falcrnm round which the
whole instrument moves.
Now, suppose the drawing is to be copied on the
same scale as the original: the point e, where the
tracer is situated, being permanent, the tubes A and
G are slid along their respective bars until the points
A e and o are all in a straight line, and the distance
A e is equal to the distance es, the tube a being exactly
midway between A and o. The pencil is then fixed in
the tube A, and the fulcrum is attached to the tube
G, so that every part of the instrument revolves
round G as a centre: the tracer 0 being moved by
hand over the lines of the drawing, the pencil passes
over the paper which is to receive the copy, and
makes a line exactly similar and equal to that de-
scribed by the tracer. For if the line B E be equal to
D E, and 1) E equal to B F, then BE D F is a parallelo-
gram, and will remain so however the 4m angles be
altered. In our figure, B and D are acute angles, and
E and E obtuse, and if the reverse were the case, the
figure would still be a parallelogram. Nor need the
4: sides be of equal length; for if opposite sides are
equal, that is, B E equal to 1) r, and D E equal to B r,
the parallelogram will still be preserved. _
If it be required to make the copy to a scale of
half the original, the fulcrum is to be attached to
the point A instead of e as before. The fulcrum and
pencil have now changed places without any change
having been made in the relative distances of A from
c and of e from c. The consequence of the instru-
ment turning round A as a fulcrum is, that the point
e, where the pencil is, moves through only one-half
of the space which the point e traverses, because the
distance is only half as great from A as c is from A.
lVhatever length of line, therefore, the tracer 0 passes
over, the pencil G will describe a line of half that
length.
Let us now suppose the copy to be on a scale of

-.};th the original, the arrangement will be as follows:
0 the tracer, g the pencil, and a the fulcrum, all being
in a right line, the distance from a to C is 41 times
as great as the distance from a to g; or the pencil
is only filth as far distant from the fulcrum as the
tracer is.
Any other proportion may be adopted, the adjust-
ment being made according to this formula :-—-As the
distance of the pencil from the fulcrum is to the dis-
tance of the tracer from the fulcrum, so is the size of
the copy to that of the original.
In the French department of the Great Exhibition,
M. Gavard’s improved pantograph excited some atten-
tion in consequence of the delicate and difficult tracings
performed by Madame Gavard by its means ; such for
example as a map of France, showing the depart—


Fig. 1563.
ments, within a space of two inches square. In this
instrument, represented in Fig. 1563, the improve-
ments consist chiefly of a better arrangement of the
fulcrum and larger size of the wheels, which add
greatly to its steadiness.
PAPER, a thin flexible leaf usually white, artifi-
cially prepared from some vegetable substance, chiefly
for writing or printing upon with ink. A species of
paper was manufactured at a remote period in Egypt,
from the papyrus or paper-reed, a plant growing
freely on the banks of the Nile. A manufacture of
paper from the bark of trees and other substances
existed also in China, from a very early date; but
among the nations of antiquity, before the introduc-
tion of paper, such substitutes were used as lead,
brass, bricks, and stone, on which national edicts and
records were written or engraved; or tablets of
wood, wax, and ivory, skins of fishes, intestines of
serpents, backs of tortoises, and the inner bark
of trees for ordinary purposes. Indeed there are
but few sorts of plants that have not been used for
making paper and books, and hence have arisen the
terms bz'blos, codea', lz'ber, folz'nm, labnla, tillnra,
plzz'lnra, sclzeda, &c., which express the several parts
of the plant which were written on. The use of
these was discontinued in Europe after the invention
of papyrus and parchment, but they are still used in
other parts of the world. The two early kinds of
manufacture above alluded to, must first be noticed,
before we describe the later invention of making
paper from cotton and linen rags, which in the
greater part of the world has superseded all other
methods of producing a material for writing on. The
Egyptian papyrus was made by laying thin plates of
bark, taken from the middle of the paper-rush, side
by side, but close together, on a hard smooth table:
other pieces of the same size and thinness were then
laid across the first at right angles; the whole was
358
PAPER.
moistened with the water of the Nile, which was
supposed to have some agglutinating property,
(though this probably resided in the plant itself,)
and pressure was then applied for a certain number
of hours. Thus a sheet of paper was formed which
required no other finishing than rubbing and polishing
with a smooth stone, or with a solid glass hemisphere,
and drying in the sun. This very simple process
was rather a preparation of a natural paper, than a
manufacture—properly so called. The process adopted
by the Chinese comes more legitimately under that
head. The small branches of a tree resembling our
mulberry-tree, are cut by them in lengths of about
3 feet, and boiled in an alkaline ley for the sake of
loosening the inner rind or bark, which is then peeled
off, and dried for use. When a sufficient quantity of
bark has been thus laid up, it is again softened in
water for 3 or 43 days, and the outer parts are scraped
off as useless; the rest is boiled in clear ley, which
is kept strongly agitated all the time, until the bark
has become tender, and separates into distinct fibres.
It is then placed in a pan or sieve, and washed in a
running stream, being at the same time worked with
the hands until it becomes a delicate and soft pulp.
For the finer sorts of paper the pulp receives a
second washing in a linen bag; it is then spread out
on a smooth table, and beaten with a wooden mallet,
until it is extremely fine. Thus prepared, it is put
into a tub with a slimy infusion of rice, and a root
called oreni; then it is stirred until the ingredients
are properly blended: it is next removed to a large
vessel to admit of moulds being dipped into it.
These moulds are made of bulrushes cut into
narrow strips, and mounted in a frame; as the paper
is moulded, the sheets are placed on a table covered
with a double mat. The sheets are laid one on the
other, with a small piece of reed between; and
this, standing out a little way, serves afterwards to
lift them up leaf by leaf. Every heap is covered
with a board and weights to press out the water; on
the following day, the sheets are lifted singly by
means of the projecting reeds, and are placed on a
plank to be dried in the sun. This paper is so
delicate, that only one side can be written on, but
the Chinese sometimes double the sheets, and glue
them together so neatly, that they appear to be a
single leaf.
This manufacture of the Chinese extended also to
the making of sheets of paper from old rags, silk,
hemp, and cotton, as early as the second century of
the Christian era, and is supposed to have been the
source whence the Arabs obtained their knowledge
of paper-making. The latter people first introduced
the valuable art of making paper from cotton into
Europe, in the earlier half of the twelfth century,
and established a paper manufactory in Spain. In
1150, the paper of Xativa, an ancient city of Va-
lencia, had become famous, and was exported to the
East and West. Notwithstanding its fame, this
paper was of a coarse and inferior quality, so long as
its manufacture was confined solely to the Arabs, in
consequence of their employing only mortars, and
I fibre.

hand or horse mills for reducing the cotton to a pulp ;
but when some Christian labourers obtained the
management of the mills of Valencia and Toledo, the
different processes of the manufacture were greatly
improved. Cotton paper became general at the close
of the twelfth and beginning of the thirteenth cen-
turies, but in the fourteenth century, it was almost
entirely superseded by paper made of hemp and linen
rags. The paper made of cotton was found not to
possess sufficient strength or solidity for many pur-
poses; a very strong paper was therefore made of the
above substances, not weakened by bleaching, accord-
ing to the present mode, which, by removing the
natural gum, impairs the strength of the vegetable
Some of these old papers, having been well
sized with gelatine, are said to possess their original
qualities even to this day.
The manufacture of paper from linen rags became
general in France, Italy, and Spain in the fourteenth
century ; the first German paper-mill was established
at Nuremberg in 1390. English manuscripts on
linen paper, date as early as 13410; but it is believed
that the manufacture did not exist here until the end
of the fifteenth century, when the Bartolomazas of
Wynkyn de Worde appeared (14.96), in which it is
stated that paper of a superior kind was made for
that work by John Tate, jun., at his mills in Stevenage,
Hertfordshire. Probably the manufactory established
by Tate was unsuccessful, for we hear no more of it,
and in 1588 a German named Spielman, jeweller to
Queen Elizabeth, established a paper-mill at Dart-
ford.‘ Still for a lengthened period our supply of the
finer kinds of paper was chiefly obtained from abroad.
In 1770 the manufacture of fine paper was esta-
blished at Maidstone, in Kent, by a celebrated maker,
J. Whatman, who had worked as ourneyman in some
of the principal paper-mills on the Continent. Not
long before this, wove moulds had been invented by
Baskerville to obviate the usual roughness of laz'cl
paper, and these, attracting attention in France, led
to the improvements which characterised the vellum
paper of that period. Holland, too, contributed its
share to the advancement of this manufacture, by
inventing cylinders with steel blades for tearing the
rags, and thus facilitating their conversion into pulp,
which by the old method of Stampers only, was a
very slow and defective process.
In 1799 the first attempt to produce paper in an
endless web was made in France by a workman
in the employ of M. Didot. The invention was
brought to England by M. Didot in 1801, and
made the subject of patents, which in 1804! were
assigned to the Messrs. Fourdrinier. Mr. Bryan
Donkin, the engineer, carried out the desired plans,
and produced, after intense application, a self'acting
machine or working model, on an improved plan, of
which he afterwards constructed many others for

(1) This mill is celebrated by a poet of that age in a work
entitled, “A Description and Discourse of Paper, and the benefits
it brings ; with the setting forth of a paper-mill, built near Dart-
ford, by a High-German, called Mr. Spilman, jeweller to the
Queen. Lond. 1588. 4to.”
PAPER.
359
Sncrron I-Surrnr or
home use and. for exportation, which were perfectly
successful in the manufacture of continuous paper.
In the year 1851 Messrs. Donkin & Co. were con-
structing their 191st machine. In 1809 'Mr. Dickin-
son, the celebrated paper-maker, invented another
method of making endless paper, the highly ingeni-
ous details of which will be noticed hereafter‘. The
Eourdrinier machines have been greatly improved
by the inventions of Mr. T. B. Crompton, Mr. Brown,
of Esk Mills, near Edinburgh, Mr. Ibotson, of
Poyle, and other skilful manufacturers, English and
foreign; so that at the present time, England, which
was long dependent for its supplies on foreign
countries, is not only able to produce an abundant
supply for home use, but to export paper to a con-
siderable amount‘.
At one time there were serious apprehensions that
the supply of linen rags would fail, and various
researches were. entered upon by ingenious indivi-
duals to find substitutes. A book written in German
by M. Schaifers so long ago as 1772,1 contains 60 spe-
cimens of paper made of different materials. This
ingenious person made paper from the bark of the
willow, beech, aspen, hawthorn, lime, and mulberry;
from the down of the asclepias, the catkins- of black
poplar, and the tendrils of the vine; from the stalks
of nettle, mugwort, dyer’s weed, thistle, bryony,
burdock, clematis, willow-herb, and lily; from cab-
'bagestalks, fir-cones, moss, potatoes, wood-shavings,
and saw-dust. Paper has been likewise made from
straw, rice, hop~bine, liquorice-root, the stalks of the
mallow, and the husks of Indian-corn. The fear of
a failure of linen rags, and the consequent necessity
for these experiments, were obviated by the discovery
of chlorine. This powerful bleaching agent will
restore many varieties of coloured linen to its original
whiteness, as well as discoloured papers and manu-
scripts, so that the same substances may be used
over and over again as a material for paper.
Inc—GRINDING, AND BLEACHING.
The quality of the paper depends greatly on that
of the linen worn in the country where it is made.
WV-here that is coarse and brown, the rags and the paper
made from them must be so too. In consequence of
the enormous demand for paper in England, (62,960
tons’ weight having paid duty in 1850,) the rags pro-
duced by a population of 27%; millions of inhabitants
in Great Britain and Ireland, are by no means suffi-
cient for the purpose. Large quantities of bagging,
and other descriptions of linen, and cotton wrappers,
old sails, cordage, and old navy stores, are employed
in making paper: the waste of our cotton. and other
spinning mills also furnishes enormous quantities of
material, which, mixed with rope, bagging, &c., pro-
duces strong and good paper for most purposes. In
addition to these sources of ‘supply, England imports
from foreign countries upwards of 8,000 tons of
material, consisting of old rags, old junk or ropes, or

(1) Sammtliche-Papierversuche von Jacob Christian Schafi'ers,
Prediger zu Regenburg. Regenséurg, 1772.
Rxes—Sonrrne-Wnsn--
old fishing nets, for making paper or pasteboard.
The following is the account of the imports in
1850:—
Tons.
From Russia .. 859
Swedenv 61
Norway 101
Denmark . 206,
Prussia 27
Germany, viz.
Mecklenburg Schwerin 78
Hanover..................... 23
Hanseatic Town's 4,449
Channel Islands 282
Italy :—
Duchy of Tuscany ................ .. 1,352
Papal Territories................ 305
Naples and Sicily ,41
Austrian Territories 43
91
Egypt 23
British possessions in South Africa 27
East Indies 29
British Colonies in North America 25

United States of Amer'ica............... 32
Brazilnuuu..voln|nnoonnncuunnnuunoluunuao--.l|b Other parts ............................... .. 52
8,124.

The quality of the rags depends very much upon
the state of civilization of the countries which pro-
duce them; the lower the degree of civilization, the
more coarse and filthy are the rags. When the rags
are received at the mill, they are sorted according to
their respective qualities, for if rags of different
qualities were ground at the same engine, the finest
and best parts would be ground and carried OE before
the coarser were sufficiently reduced to make a pulp.
In the sorting of rags intended for the manufacture
of fine paper, hems and seams are kept apart, and
coarse cloth. separated from fine. Cloth made of
tow should be separated from that made from linen,
cloth of hemp from cloth of flax. Even the degree
of wear should be attended to, for if rags compara—
tively new are mixed with those which are much
worn, the one will be reduced to a good pulp, while
the other is so completely ground up as to pass
through-the hair strainers; thus occasioning not only
loss of material, but less of beauty in the paper, for
the smooth velvet softness of some papers may be
produced by the finer particles thus carried off. The
pulp produced from imperfectly sorted rags has a
cloudy appearance, in consequence of some parts
being less reduced than others, and the paper made
from it is also cloudy, or thicker in some parts than in
others, as is evident on holding a sheet up before the
light. When it is necessary to mix different qualities
of rags together to produce different qualities of
paper, the rags should be ground separately, and the
various pulps mixed together afterwards.
The rag-merchants sort rags into five qualities,
known as Nos’l, 2, 3, 4!, and 5. No. 1 or superfine,
consisting wholly of linen, is used for the finest
writing papers. No. 5 is canvass, and may, after
bleaching, be used for inferior printing papers.
There is also rag-tagging, or the canvas sacks in
which the rags are packed: also cotton coloured
rags of all colours, but the blue is usually sorted out
360
PAPER.
or making blue paper. Common papers are made
from rag-bagging and cotton rags.
An operation sometimes required after unpacking
the rags, is to put them into a cluster, which is a
cylinder 4: feet in diameter and 5 feet long, covered
with wire net and enclosed in a tight box to confine
the dust. A quantity of rags being put into this
cylinder, it is made to rotate rapidly on its axis, and
thus a good deal of dust is shaken out which might
otherwise vitiate the air of the rag-cutting room.
The sorting is done by women and children in a
large room: each sorter stands before a table frame,
covered at the top with wire cloth, containing about
nine meshes to the square inch. To this frame a
long steel blade is attached, in a slanting position, as
shown in Fig. 156%; and the sorter divides the rags
fin :
\ \: lbht-‘v_‘— pr‘
3 "II
1;l'-~
‘(l'l'f :\ i
x W
1 ‘ ll
~M‘
l.‘
A
' :f\\\,
I\ ‘ l
/
Fig. 1564. CUTTING BAGS.
into shreds by drawing them against the sharp edge
of this knife; a good deal of the dust which is shaken
out in this operation falls through the wire-cloth into
a box beneath. The sections of rag are thrown into
the compartments of the frame, according to their
fineness. In importing rags some attention is paid
to their quality by the foreign dealers, so that each
bale is tolerably uniform. Formerly this was not the
case, and in sorting a bale the woman had a piece of
pasteboard hung from her girdle and extended on her
knees, upon which with a long sharp knife she un-
ripped seams and stitches and scraped off any adher-
ing dirt. The rags were sorted according to their
fineness, into the superfine; the firze; the stite/zes of
the fine; the middling; the seams and stile/les of the
middling, and the coarse. These divisions are more
or less observed at the present day. The very coarse
parts are rejected or laid aside for making white—brown
paper.
1 The sorted rags are washed with hot water and
alkali, in an apparatus formed exactly on the prin-
ciple of the baa/ring Icez'rs or loafers, described under
BLEACHING (Figs. MO, 1111) ; or the washing is per-
formed at one of the mills or engines about to be
described.
The rags are ground into pulp in mills, now made
sufiiciently powerful to reduce the strongest and
toughest rags. Formerly before the invention of
mills, or when they were of much less power, it was
customary to pile the rags in large stone vats, and
leave them for a month or 6 weeks with frequent

stirring and watering to ferment or rot, by Which
means the fibres became sufficiently loose to be
reduced to pulp by pounding in wooden mortars with
stampers. The arrangement of these mortars is thus
described in an old treatise on the manufacture of
paper :—-—“ These mortars are cut out in a block of
heart of oak, well seasoned, the cavity being of an
oval figure about 18 inches broad, 30 inches long,
and 18 or 20 in depth; the bottom concave and lined
with an iron plate an inch thick, 8 inches broad, and
30 long, shaped inward like a mould for a salmon
with the head and' tail rounded. In the middle of
the mortar is a cavity beneath the plate, and 41 or 5'
grooves are cut, forming channels which lead to a
hole out from the bottom of the cavity quite through
the block: it is covered by a piece of hair sieve
fastened on the inside. This plate is grooved to
make teeth, on which the teeth of the hammers act,
to cut the rags in pieces. The use of the hair sieve
is to prevent anything from going out except the
foul water. Two hammers or pestles work side by
side in each mortar, and are lifted alternately by the
mill: they are sometimes made in the same manner
as the stampers of an oil-mill, to lift perpendicularly.
In other mills they are large hammers moving on a
centre, like a fulling mill, and lifted by cogs upon the
mill shaft in the same manner. The mortars are
kept constantly supplied with fair water by little
troughs, leading from a cistern which is kept full by
small buckets affixed to the floats of the water wheel;
these, when they have raised the water to the top,
pour it out into the cistern in the same manner as the
Persian wheel.”
The mortars were superseded by what are called
engines, a Dutch invention well adapted to the pur-
pose. The engines are sometimes arranged in pairs
on different levels, the bottom of one being higher
than the top of the other, so that the contents of the
higher engine may be let off into the lower. In the
upper engine, called the washer, the rags are first
worked coarsely with a stream of water running
through them to wash and open their fibres: this
reduces them to what is called lzeelf sz‘zfl; they are
then let down into the eeatz'eg engine to be ground
into pulp fit for making paper, Each engine consists
of a large wooden vat or cistern vv, Figs. 1565, 15 66,
of oblong figure on the outside, with the angles cut
off: the inside, which is lined with lead, has straight
sides and circular ends- Or the vat may be entirely
formed of cast-iron. It is divided by a partition
:9 r, also covered with lead. The cylinder 0 is firmly
fixed to the spindle s, which extends across the
engine and is put in motion by the pinion W, which
engages other wheels set in motion by water or steam
power. The cylinder is of wood, but is furnished
with a number of teeth or cutters attached to its
surface parallel with the axis, and projecting about
an inch from it. Immediately below the cylinder is
a block of wood B, also furnished with cutters, so
that when the cylinder revolves its teeth pass very
near those of the block, the distance between them
being regulated by elevating or depressing the bear.&
PAPER.
361

ings ll, on which the necks of the spindle ss are
supported. These bearings are made on two levers
ll, which have tenons at their ends fitted into upright
mortises made in stout beams b b, Fig. 1567, bolted
to the sides of the engine. The levers ll are
movable at one end of each, the other ends being
fitted to rise and fall on bolts in the beams b b, Fig.
1567, as centres.
The front one of these levers, or











V.
. ;f’ 9 ‘W’ 9 Ema. I“ wrap
‘.__"I'// c _ g ,, \ j t u’
it till it _w _\ at _
A“
O Fig.1566.
that nearest the cylinder 0, can be raised or lowered
by turning the handle it of the screw, which acts in a
nut n, fixed to the tenon of l, and rises through the
top of the beam b, upon which the head of the screw
takes its bearing. Two brasses let into the middle
of the levers ll, act as bearings for the
spindle of the engine: by turning the
h screw the cylinder is raised or lowered,
.:i
.
1

7 l
fit llll m‘?
b
'n
1


?:_-



lillll
,ivtmm
H l l ‘l l
I/////
l

\
__.--__-.Q .m
I
, ,I....;.I..l,,l,,.,,...“ .
b
Fig. 1567. % /
a/Z
\Qxr
and made to cut coarser or finer by enlarging or
diminishing the space between the two sets of
cutters. At one part of the vat is a breasting
is’, made of boards and covered with sheet lead,
curved to the form of the cylinder and nearly in con‘
tact with its teeth. An inclined plane I, passes from
the bottom of the vat to the top of the breasting
which terminates in the block B. The vat is supplied
with water from the mill-dam by means of pumps
worked by the water-wheel. The water is first dis-
charged by the pipe 1?, Fig. 1566, into the cistern c, the

supply being regulated by the cock in the pipe. A
grating covered with a hair strainer is fixed across the
cistern to prevent any solid impurity from passing into
the vat; or the water may be strained through a flannel
bag tied over the mouth of the pipe P, as shown in
the figure. The vat being full of water and a quantity
of rags put in, the cylinder is set in motion, the effect
of which is to produce a regular current in the water
in the direction of the arrows, by which the rags are
drawn between the cutters of the cylinder and the
teeth of the block; this cuts them to pieces: they
are then thrown over the top of the breasting upon
the inclined plane, down which they slowly slide and
pass round the partition, and in about 20 minutes are
again brought between the teeth of the cylinder and
the block. The mode in which the rags are cut will
be understood by considering that the teeth of the
block are placed somewhat inclined to the axis of the
cylinder, as shown in Fig. 1568, while the teeth of the
cylinder are parallel to its axis, so that the cutting
edges meet at a
small angle and
pass over each
other something
like the blade


of a pair of
shears, and the
Fig. 1568.
rags between
them are cut up in a similar manner; and as they are
brought many times under the action of the cutters,
and must necessarily present their fibres each time in
different directions, they are at length reduced to the
condition of pulp. In some cases the cutters in
the block B, instead of being straight, are bent
to an angle in the middle, in which case they are
called elbow plates; but in either case the edges of
the cutters are curved so as to suit the curve of the
cylinder. The plates or cutters are first screwed
together and then fitted into a


cavity cut out in the wooden % Vlilllillllllllfji ’/
block B, shown on a larger scale, [%
Fig. 1569; the edges of the ‘F _ '
zg. 1069.
cutters are bevelled away on
one side only. The block is fitted firmly into the
bottom of the vat by being dove-tailed into it, and
fastened by a wedge, on removing which, the block can
easily be taken out for the purpose of sharpening the
cutters. The cutters of the cylinder, Fig. 1570, are
fixed in equi-
distant grooves,
of which there
are about 20:
for the washer,
each groove has
2 cutters or bars
put into it; then
a fillet of wood is driven in fast between them, and
the fillets are kept fast by spikes driven into the
solid wood of'the cylinder. In each groove of the
beater there are 3 bars and 2 fillets. In the beat’
ing engine the cylinder revolves quicker than the
washer, the rate being from 120 to 150 times per


Fig. 1570.
362
PAPER.
minute. The centrifugal force thus produced would
project all the rags from the vat were it not for a
wooden box or cover w, Fig. 1566, one side bf which
rests on the edge of the vat, and the other on the
edge of the partition r r. At f f are wooden frames
covered with hair or wire cloth, and immediately
behind these the box is made with a bottom, and
a ledge towards the cylinder. At 00’, Fig. 1565,
are two openings or spouts which convey the foul
water from the engine. As the cylinder revolves a
large quantity of water and rags is thrown up against
the sieves; the water passes through, runs into the
trough at 0, and escapes by the pipes. At g g, Fig.
1566, are grooves for two boards which cover the
hair sieves, and prevent water from going. through
them when it is required to retain the water in the
engine, as is the case in the beating engine, which,
indeed, is not always furnished with these waste
pipes, but with a drum or cylinder G of wire gauze,
which is caused to revolve slowly by means of the
upright spindle, as shown in Fig. 1571. As the water
in the vat rises above a certain level it drains into
this drum and escapes, but the meshes of the drum
are too fine to allow any of the ground pulp to escape
with the water. In a mill with 5 engines, 3 are
heaters and 2 washers, the latter getting through their
work more quickly than the former. The washing
engine produces considerable vibration; for since it
revolves 120 times per minute, and has Zi0 teeth, each
of which passes by 12 or 111 teeth of the block at every
revolution, it makes nearly 60,000 cuts per minute,
each single out being loud enough to produce a sound.
The heater, with 60 teeth, and 20 to 2d cutters in
the block, makes 180,000 cuts per minute, the effect
of which is a low musical note or hum, audible at a
distance from the mill. In the washing engine the
rags are opened, their fibres separated, and the dirt
removed. Any small solid impurities are collected in
the trough a, Fig. 1566. When first put in, the rags
are worked gently, the cylinder is raised some way
above the block so as to rub rather than out the rags;
at the same time a copious stream of water is ad—
mitted; after 20 or 30 minutes, the cylinder is let down
./
\
n’
7 2;».







' Flt


Fig.1571. nnx'rme ENGINE.
so as to cut the rags, and the operation Is at first so
violent that the cylinder is often jerked or heaved up.
After 3 or 42 hours the engine works steadily; the

rags are cut up very small, and form what is called
ltalf stzfi': this is let out into a basket, which retains
it while the water flows. off. For some kinds of
paper the half stuff is left to mellow, or ferment ; but
it is usual at this stage to blcac/t the stuff, which is
done by a solution of chloride of lime in stone vats,
or by using this solution instead of water in the
engine at the last stage of the washing process, the
slides gg being put down in the cover to prevent
the loss of the solution. In the course of an hour
the yellow rags or half stuif are converted into a snow
white. This is then put into the beating engine, and
in ll or 5 hours it is ground into a fine pulp, a little
water being let in from time to time, but none being
allowed to escape. The quality of the water has con-
siderable influence on that of the paper; the purest
water is of course the best; water from chalky soils
introduces lime into the pulp, and this forms a slight
incrustation upon the moulds, which is washed off
from time to time by vinegar.
In order to prevent common ink from running upon
paper, size is introduced at a certain stage of the ma-
nufacture; but printing-ink being oily instead of
watery, and moreover of greater consistence than
common ink, is not so liable to run. Hence, for cer-
tain printing papers, the sizing is done in the beating
engine towards the close of the operation. The size
consists of finely pounded alum mixed with oil, about
a pint and a half of the mixture being thrown into
the engine at intervals during the last half-hour of the
beating. The blue is produced by smalt, or artificial
ultramarine.
Sncrron IL—Pxrnn-n'xxrne- BY HAND.
When the stuff is properly prepared, it is run out
by the pipes 00', Fig. 1566, into thestaf chest,
where the different kinds are mixed preparatory to
moulding. From tln's chest. it is transferred to vats
or tubs, each about 5 feet in diameter and 2,‘, feet
deep, provided at top with planks enclosed inwards to
prevent the stuff from running over during the mould-
ing. Across these planks is a board pierced with
holes at one extremity, for supporting the mould.
The stufi in the vat is kept at the proper tempera-
ture by a small grate placed in a hole lined with
copper, at the side of the vat. The fuel is charcoal or
coke, or the fire is entirely confined to the other side
of the wall, a hole through it being made into the
side of the vat. In this way smoke is prevented.
The paper is made into sheets by means of the mould
and (lac/ale, Figs. 157 2, 1573. The mould is a square
‘ » frame, or shallow box of mahogany, covered at the top
with wire-cloth : it is an inch or an inch and a half wider






Fig. 1572.
than the 51166’6 Of paper intended to be made upon it.
The wire-cloth of the mould varies in fineness with
PAPER.
363
that of the paper and the nature of the stuff ; it con-
sists of a number of parallel wires stretched across
a frame very near together, and tied fast through
holes in the sides: afew other stronger wires are also
placed across at right angles to the former: they are
a considerable distance apart, and they are bound to
the small wires at the points of intersection by means
of fine wire. In several kinds of writing-paper the
marks of the wires are evident from the paper being
thinner in the parts where the pulp touched the
wires. In what is called wove paper, there are no
marks of the wires: these are avoided by weaving
the wire in aloom into a wire-cloth, which is stretched
over the frame of the mould, and being turned down
over the sides is fastened by fine wire. The water-
mar/e in paper is produced by wires bent into the
shape of the required letter or device, and sewed to
the surface of the mould ;-—-it has the effect of making
the paper thinner in those places. The old makers
employed water-marks of an eccentric kind. Those
of Caxton and other early printers were an ox-head
and star, a collared dog’s-head, a crown, a shield, a
jug, 850. Afool’s cap and bells employed as a water-
mark, gave the name to foolseap paper; a postman’s
horn, such as was formerly in use, gave the name to
post‘ paper.
The deckle is a thin square mahogany frame, bound
with brass at the angles: its outer dimensions corre
spond with the size of the mould, and its inner with
that of the sheet of paper. The use of the frame is
to retain the pulp upon the wire-cloth: it must be
quite flat, so as to fit the cloth of the mould, other-
wise the edges of the paper will be ragged and badly
finished. When the deckle is placed upon the4 wire
of the mould it forms a shallow sieve, in which the
paper-maker takes up a quantity of the pulp sus-
pended in water, and the water draining through,
leaves the pulp in the form of a sheet upon the wire.
The deckle is not fastened to the mould, but is held
to it by the workman grasping the mould and deckle
together in both hands at the opposite sides. When
the sheet is moulded the deckle is removed, and the
sheet is taken up from the wire by laying it on a piece
of fill or woollen cloth. These felts prevent the
sheets from coming together, and they also serve to
imbibe a portion of the water from the damp and
loosely cohering sheet.
In the moulding of paper there are usually three
men employed, viz. the clipper, the coaster, and the
Zzj’ler. The first, having filled the vat with pulp,
mixes it up well with a pole, and afterwards with a
perforated paddle; but, by a better arrangement,
a mechanical stirrer is often used 5 this consists of a
small wheel or log, which being maintained in con-
stant motion, keeps the pulp suspended. The stuff
should float in close regular flakes; if not, it is a
proof that the grinding has been badly done. The
dipper stands in a niche made in the table which sur-
rounds the vat, and holding the mould in both hands,
with the deckle firmly pressed to it, he inclines it
a little towards him, dips it into the vat, and brings
it up again in a horizontal position. The superfluous

part of the pulp flows over the sides; that which
remains, and is according to the judgment of the
dipper suificient for a sheet of paper, is shaken gently
from right to left, and up and down, until it is equally
spread over the whole surface of the mould. This
requires great skill and experience. As the water
drains through the wire, the fibres of the pulp arrange
themselves regularly on the wire-cloth. The mould
is then placed on the edge of the vat, the deckle is
taken off, and the mould slid along the board across
the vat to the place where the sheet is to be laid, or
taken off. The holes at the end of the board allow
the water from the mould to drain into the vat. In
the meantime the dipper places the deckle from the
first mould upon a second mould, and proceeds to dip
another sheet. The coucher takes up the first mould
in his left hand, raises it gently, and places it in an
inclined position against one or two small pins which
are driven into .the board on the edge of the vat ; in
this position it is left for a few seconds to complete
the draining, while the coucher extends a felt on
which he applies the mould in order to take off the
sheet. This being done, he returns the mould to the
dipper. In this way they proceed, alternately laying
a sheet and a felt, until 6 quires of paper are made:
this is called a post, and 2 men can make 20 posts
a-day if the sheets are not very large. Whenever
a post is completed it is put into a screw-press, which
forces out a large quantity of water, hardens and con-
solidates the paper, and to a certain extent smooths
down the rising-s and hollows made by the wires in
laid paper. When a second post is ready the first is
taken out by the lifter, who takes the sheets off the
felt, and makes them up into a neat and compact pile
without the felts ; and when several piles are thus
produced from several posts, they are put into a
second or wet-press, as it is called. The sheets being
pressed in contact with each other, a large quantity
of water is got out, the sheets become considerably
stronger, freckles or felt marks are removed. In pro-
portion as the water is removed the fibres of the
pulp interlace, and become felted together, so as to
form akind of felted cloth. When the paper is taken
out of the press it is separated into small parcels of
7 or 8 sheets in each, for the purpose of drying. The
drying is conducted in extensive lofts in the upper
parts of the mill. The sheets are taken up upon a
piece of wood, shaped like a T, and hung upon hair
lines stretched across large horizontal wooden frames,
called lrz'lbles, and as these are filled they are lifted
up between upright posts to the top of the room, and
retained by pegs put into the posts; another frame is
then filled, and put up in its turn, until the loft is
filled. Air is admitted to the lofts by means of louvre
boards. When sufiiciently dry, the paper is taken
down, and slee/eecl, clresseel, and 8/10/6672, to get rid of
dust, and to separate the pages. It is then laid in
heaps in the warehouse preparatory to sizing. The
size is made from the shreds and parings of leather
and parchment; it is nicely filtered, and a little alum
added. A number of sheets are then dipped into the
size and separated so as to expose both surfaces of
364:
rnrnn.
each sheet: the sheets are taken out, turned over,
and dipped a second time. About a dozen handfuls
being thus dipped they are made into a pile, with a
thin board or felt between every two handfuls, and
pressed to get rid of superfluous size which flows
back into the size vessel. The paper is again trans-
ferred to the lofts, and dried. This being complete, it
is taken down, carried to a building called the Saul,
(probably a corruption of the German seal, or the
French salle, a hall, or 10 rge room,)_ where it is ea:-
amz'rzezl, finished, and pressed. The imperfect sheets
(ret/ee) are removed. The press called the clip-press
is a powerful one, or the hydrostatic’press is used.
After one pressing the heaps of paper are parted, that
is, they are turned sheet by sheet, so as to expose
new surfaces : the press is again used; then there is
another parting, and so on, several times. The paper
is next made into quires and reams, and once more
pressed. ’ '
Connected with the sizing of papers, is the blueing;
which is said to have originated in the suggestion of
a paper-maker’s wife, who thought that the practice
of improving the colour of linen, while passing through
the wash, by means of a blue-bag, might also be
advantageously applied to paper. A blue-bag was
accordingly suspended in the vat; and the effect
proved to be so satisfactory, that it led to the intro-
duction of the large and important class of blue
writing papers. It was soon found that smalt gave
a better colour than common stone-blue; and smalt
continued to be used for many years; but when arti-
ficial ultramarine came to be manufactured at a very
low cost, and in a great variety of tints, this beautiful
colour gradually superseded smalt in the manufacture
of writing paper. The introduction of ultramarine,
however, led to some difficulty in sizing the paper.
So long as smalt continued to be used, any amount of
alum might be employed: and it was actually added
to the size to preserve it from putrefaetion. But as
artificial ultramarine is bleached by alum, it is neces-
sary to add this salt in very small proportions to the
size for blue papers : and the consequence of this was,
that the gelatine was no longer protected from the
action of the air, which led to incipient decomposition;
and, as happens in such cases, the putrefaction, once
commenced, proceeded after the size was dried on the
paper. This gave to the paper a most offensive smell:
and whole bales of paper were returned to the maker
as unsaleable.
Three remedies were tried for this serious defect :—~—
1. The use of antiseptics, such as camphor, which
would not decolorize the ultramarine. This method
failed in consequence of the powerful antiseptics
being poisonous, odorous, too volatile, or too costly.
2. 'Sulphurous acid was used, in order thoroughly to
purify the screws or clippings of skins, before they
were converted into size. This plan was patented by
Mr. Itattray, of Aberdeen, and adopted by several
paper-makers. It answered its purpose admirably,
but it was rather troublesome and somewhat costly, as
the patentee had to be paid for his licence. The great
value of sulphurous acid, consisted in its property of

arresting putrefaetion even after it had commenced.
The screws were even permitted to putrefy slightly,
in order the more readily to get rid, by long macera-
tion, of adhering hair, cellular tissue, and muscular
fibre, &c. Putrcfaction was then arrested by washing
with an aqueous solution of sulphurous acid, and the
size prepared from scrows treated in this way, dried
quite sweet upon the paper. 3. The cost of the sul-
phurous acid process, led paper-makers to try the
effect of improved methods of drying the paper after
sizing; and in this they succeeded perfectly. All
experience showed that if the size were quite free
from taint when applied to the paper, and were
quickly dried on it, putrefaction did not subsequently
occur; if, however, decay had commenced, it could
not be arrested by drying only. The method of dry-
ing which was found to succeed best, was to pass the
paper over hollow skeleton cylinders, within each of
which a fanner was kept rapidly revolving; the air of
the room was heated artificially. The size is now
made in the ordinary way.
a After the paper is made up into reams it is again
pressed, if possible, for 10 or 12 hours. After this,
it is tied up in a wrapper with a label on it, which is
filled up by the manufacturer and the excise oflicer
respectively ; the latter weighs the paper and stamps
the wrapper, to indicate that the amount of duty has
been charged to the maker.
SECTION III—PArnn-MAKING :BY MACHINERY.
The slow and difficult process of moulding the
separate sheets of paper by hand, has to a great ex-
tent been superseded by the introduction and gradual
improvement of the very beautiful machine referred
to in our introductory remarks. By means of this
machine a process which, under the old system, occu-
pied about 3 weeks, is now performed in as many
minutes. Within this brief space of time, and the
short distance of 30 or 40 feet, a continuous stream
of fluid pulp is made into paper, dried, polished, and
cut up into separate sheets ready for use. The paper
thus produced is moderate in price, and for a large
number of purposes superior in quality to that which
was formerly made by hand. In fact, the machine-
made papers can be produced of unlimited dimen-
sions; they are of uniform thickness; they can be
fabricated at any season of the year; they do not
require to be sorted, trimmed, and hung up in the
drying-house—operations which formerly led to so
much waste, that about 1 sheet in every 5 was
defective.
With the assistance of a steel engraving we will
endeavour to give, first, a general idea of the common
form of a paper—making machine, and then a more
detailed notice. At one extremity of the building
a large vat v, Fig. 1, is kept constantly supplied
with pulp, or properly prepared stuff, which is pre—
vented from subsiding by the revolution of the stirrer
s upon its axis a. The stuff flows from the vat by a
cock 0, which is opened more or less, according to the
thickness of the paper intended to be made. The stuff
falls into the trough z‘, where it meets a large supply

A... as 3 Annie m. ease. . an




i it'll’
i .=. i... -.a§=s_=.....§l_ . - : .....==.=m=i:.,.=.==...i=...___SE ..
'w"‘- ‘L









PAPER.
365
of water, which has already passed through the web
of the pulp, as will be explained hereafter. The stuff
then passes through a strainer s, for the purpose of
separating from the pulp knots, sand, and hard sub-
stances, which formerly caused so much damage to
types and valuable wood engravings in the printing.
Before the introduction of this strainer by M. Ibotson,
the knots, 850. were scraped out of the paper after it
was made in the salle, to the injury of its surface,
thereby causing so much relree (damaged paper) to
otherwise good and well-made paper. A common
form of strainer is a rectangular trough of brass or
gun-metal 5 or 6 feet long, 2 feet wide, and the sides
about A inches deep. The bottom is formed of a
number of heavy bars with smooth polished surfaces;
they are each about an inch broad; they rest on a
projecting ledge, and are firmly fixed in by wedges,
so as to be almost in contact; the spaces between
them allowing the fibres to pass lengthwise, but
keeping back all knots and extraneous substances. A
light shaft of brass or iron passes above the strainer,
and above each end is a cam is, or notched wheel,
working into the frame of the strainer, so that as
the shaft revolves, the strainer is raised at every
notch, and descends by its own weight, thus produc-
ing a continual jerking motion, making about 130
strokes per minute. As the knots accumulate, a
man draws them towards him with a wooden rake,
and shuts them or? from the rest of the trough by
means of a wooden hatch covered with felt, which
he puts across the trough. Then scooping out the
knots, &c., he takes out the sluice, and repeats the
operation as often as required.‘ The stuff thus
strained, flows upon a leathern apron a, which con-
ducts it to an endless wire-cloth w a, over which the
web of paper is formed. This wire-cloth is about 28
feet in length, and varies from 48 to 100 inches in
width, and has about 60 holes in the lineal, or 3,600
in the square inch; it is kept in motion upon a
number of small copper rollers about 1% inch in
diameter, and the same distance apart. The rollers
are supported by a frame, to which a slight but rapid
lateral movement is imparted by means of a small
crank c c’, and the vibration is made more or less
rapid, according to the nature of the stuff. This
shaking motion facilitates the escape of the water
through the wire-cloth, and the felting together of
the fibres of the pulp. The water holding a good
deal of the flour of the pulp, is received in a large
wooden vessel or save-all placed beneath the wire-
cloth, and from this vessel it is raised by means of
scoops, and poured into the trough t, where it dilutes
the supply of stuff from the vat. The edges of the
paper on the wire gauze are formed of belts, or deckles
of linen and caoutchouc clrl; they are half an inch
thick, and 16 feet long, and are kept distended by the
system of friction rollers represented in the engrav-
ing. Motion is given to them by the wheel 20 acting
on the axis re, and they press with moderate force,
not suficient to prevent the free motion of the wire-
cloth, but enough to prevent the pulp from flowing
off laterally before the fibres have set. By the time

the deckle-straps leave the wire-cloth, the stuff is‘no
longer fluid, although much water continues to escape
from it. The wire-cloth with the pulp upon it passes
on until it comes to a couple of reel-press cylinders r’,
as they are called, the lower of which is of metal, but
covered with a jacket of felting or flannel; the upper
one is of wood made hollow, and covered first with
mahogany, and then with flannel. To prevent the
paper from adhering, the surface of this upper roller
is kept wet by a jet of water, j, running along a
trough, as will be more particularly noticed in the
description of Fig. 2. These cylinders give the
gauze with the pulp upon it a slight pressure, which
is repeated upon a second pair of wet-press rolls r”
similar to the first. The paper pulp is then led on
upon an endless felt or blanket, ff, which travels at
exactly the same rate as the wire-cloth, otherwise the
paper would be torn. The wire cloth turns round
under the wet-press cylinders to obtain a new supply
of pulp, and is kept distended by copper friction
rollers, which move by the friction of the cloth. The
water which escapes from the wet-press rolls is re-
ceived by the save-all ear. The endless felt conveys
the web of paper, still in a very wet state, between
cast~iron cylinders, where it undergoes a severe pres-
sure, which gets rid of much of the remaining water,
leaving the web sufiiciently firm to be handled. The
paper is passed betweena second pair of press-rollers,
which remove the mark of the felt-from the under
surface. It is then passed over the surface of the
cylinders heated with steam, s‘ s2 s3 ; and when it has
passed over about 30 lineal feet of heated surface, it
is wound upon a reel n, ready for the cutting machine,
or it passes at once to the cutting machine, as will
be noticed hereafter. \
We will now, with the assistance of Fig. 2. of the
steel engraving, describe this machine with greater
minuteness. Commencing at the left-hand extremity
of the machine, we have a vat at '6, kept well supplied
with pulp, which is held in suspension by the motion
of a small agitator or hog. The pulp is further di-
luted in this vat by the water which has already
passed through the wire gauze into the save-all at is,
from which it is raised by a Persian wheel, and poured
into the vat b by the trough a. The bottom of the
vat b is arranged so that a jet of steam may pass
through it, and raise the temperature, as is some-
times required for coarse pulps, At a is a partition,
which forces the pulp to pass near the agitator, so as
to be properly suspended in the water before it flows
upon the strainer (l. After having been freed from
knots by passing through the strainer, the purified
pulp escapes by a cock, and, falling upon a leathern
apron at e, is conducted to the wire-cloth. The water
drains through the wire-cloth, and the fibres of the
pulp completely cover and conceal it. In order,
therefore, to distinguish the paper, it is marked in
our figure with a dotted line, while the wire—cloth,
and afterwards the blankets, are distinguished by a
continuous line. The wirescloth, which is kept dis-
tended by the friction rollers an, extends from era to
qg, and where it first receives the pulp; it is sup-
366
PAPER.
ported in a horizontal‘ position upon hollow copper
rollers ff; and here the width of the paper is regu-
lated by the deckle strap, which is moved along the
edge of the wire-cloth, in flat contact with it, and
constantly returning, by means of the system of
‘pulleys pl 72, supported by the frame s. The support-
ing ‘arms of some of these pulleys admit of being
adjusted‘so as to regulate the tension of the strap.
There is, of course, a similar system on the other side
of the machine. A jet of water, supplied by the
cistern 0, constantly plays upon the deckle strap, for
the purpose of removing the fibres of pulp which it
takes up from the wire-cloth.
The wire-cloth rollers ff; the frame s, and the
friction rollers a n, are supported by the iron rods m m.
The whole system has a rapid to and fro motion im-
parted to it by means of a short crank connected with
the movable supports mm. This motion serves to
distribute the pulp evenly over the wire-cloth, and to
facilitate the draining through of the water; this is
received in the save-all ink, which is raised on the
firm supports 2 l. The water from the save-all flows
by a pipe into a vessel in which the scoop buckets of



Fig. 1574. Fig. 1575.
a Persian wheel, shown in two views, Figs. 157 4:,
157 5, dip in succession as the wheel revolves, and
raise the water to the trough placed just above the
axis of the wheel; this trough conveys the water to
a, as already noticed. As the wire-cloth advances
_: , “up” _
- - “is


illlllllllllll
_.__-—- 1


lllllll
T==
__
lllllll


it passes over a vacuum box at s s, where the air is
kept constantly rarefied by means of the air-pumps,

Fig. 1576, which communicate therewith by the three
vertical pipes covered at the top, with valves opening
upwards. The action of this pump will be seen at a
glance: three bell-shaped vessels moving vertically
by means of guide-rods in tanks of water over the
vertical pipes, are attached by cranks to a horizontal
axis, the revolution of which causes the vessels to
move up and down. During the upward motion of
one of these vessels the air within it becomes rarefied,
and the consequence is, that air rushes from the
vacuum box, s 8, along the vertical pipe, forcing open
the valve at the top in order to restore equilibrium
within the vessel. During the downward motion the
valve at the top of the vertical pipe is closed, and a
valve at the top of the bell vessel opened whereby the
air is discharged preparatory to a fresh ascent, when
the action is repeated as before. As there are three
of these bell-shaped vessels, the cranks for which are
set at right angles to each other on the same axis,
one of these vessels is always in full action; the
consequence is, that tolerably dry air is constantly
streaming through the pulp and wire-cloth into
the box s s, whereby a large quantity of water
is drained off, and the pulp becomes consolidated and
better prepared for being transferred from the wire-
cloth to the blanket. Should, however, any accident
occur to prevent the progress of the work, the paper
(which of course is constantly accumulating by the
motion of the wire-cloth) is directed into the wooden
chests l l; a pipe pierced with holes extends across
the wire-cloth, and the jets of water from these holes
detach the paper from the wire-cloth. But should
all go well, the wire-cloth, with the wet pulp upon it,
is passed between two copper rollers g 9, covered with
woollen cloth; and to prevent the paper from adhering
to the cloth, the rollers are kept wet; for which pur-
pose a wooden board covered with felt presses by its
edge along the whole length of the top cylinder, the
pressure being regulated by weighted levers at the
two ends of the board. In this way a sort of trough
is formed by the angle of intersection of the board
and the cylinder, so that a jet of water introduced on
one side flows along the trough and escapes at the
other side. 9' is the support to the upper cylinder. At
y the paper is transferred from the wire-cloth to the
blanket, which is supported by the couch rolls pp, and
kept distended by the roll 2. The blanket conducts
the paper to the press rolls me. These rolls are of
iron, cast solid: above the upper roll a steel edge or
doctor is made to press so as to remove any adhering
fibres of the pulp, and to keep a constantly clean sur-
face. Should the paper stick to the cylinder, the doctor
prevents it from proceeding further and injuring the
blanket. The blanket cannot be used for more than
eight days without being removed and washed with
soap: with care one blanket may last a month, with
three washings. There must always be a supply of
blankets, so that a new one may be substituted in
case of accident; for if a small hard substance were to
become entangled with the blanket, and to pass with
it under the rolls, it would make a hole in it and de-
stroy it. The rolls a u are adjusted in their bearings by
PAPER.
367
the screw b, so as to exert a greater or less pressure,
and the water which is thus forced out of the paper
and blanket is received in the chest or. After passing
through the rolls a a, the paper is conducted by the
blanket to within a short distance of the hollow copper
roller 1. Here the blanket parts company with the
paper, and returns by the rollers y z y, to perform
duty again.
The paper proceeds for a short distance without
any other support than its own cohesive force, which
was in great measure imparted to it by the strong
pressure of an. The paper proceeds to the upper
roll 1, and then obliquely to another pair of rolls r r,
where it meets with a second blanket moving on rolls
2 2, and receives another pressure, any water which
escapes being received in a small chest :0. The frame,
which rises above the rolls rr, allows a much longer
second blanket to be used, the roll 2 supporting it
above, and the proper tension being given by the
screw so. The paper, after the pressure of r r, passes
over the top roller, and thence to the roll marked 3,
and is conducted to the steam cylinder $1, the mark of
the felt being removed by the pressure which it re-
ceives between the roller 3 and the cylinder s. A
dry blanket, moving on the rollers 4rd, conducts the
paper from s‘ to s2. The number of the steam
cylinders may vary from 3 or 41 to 20 and upwards.
The steam is conducted into them by pipes from the
boiler, as shown in the lower figure. At 5 is a cast-
iron cylinder, which presses strongly by means of a
weighted lever against the cylinder s2. At 6 6 are
rolls supporting a blanket which conducts the paper
first under s“, which can be made to press with its
whole weight on the roll 7, and afterwards over the
surface of s“. At 8 are rolls which serve to adjust the
blanket. From the last steam cylinder, the finished
paper passes to the drums, or reels, r’ r”, and is
wound upon one of them. After the reel has made 130
revolutions, a spring which holds in the ends of the
reel is removed. The reel which is attached to the
arms, which move on the axis a, is moved quickly
round, so as to change places with the other reel:
the paper is torn across, the end of the web is
attached to the reel now in gear, which is filled while
the paper is being cut off the reel last removed.
The paper-machine moves at the rate of from 25
to 40 feet per minute, so that scarcely 2 minutes are
occupied in converting liquid pulp into finished
paper, a result which, by the old process, occupies
about 7 or 8 days. If the machine produce 10 lineal
yards of paper per minute, or 600 per hour, this is
equal to a mile of paper in 3 hours, or 4 miles per
day of 12 hours. The paper is about 54: inches
wide, and supposing 300 machines to be at work in
Great Britain, working on an average 12 hours a-day,
the aggregate length of web would be equal to 1,200
miles, and the area 3,000,000 square yards.
* In 1830 Mr. John Wilks obtained a patent for a
channeled and perforated roller, called a dandy, to
remove part of the water from the pulp, to facilitate
couching, to enable paper to be made with increased
rapidity, and to close its upper surface.


In 1830 Mr. Thomas Barratt obtained a patent for
inserting the water mark and maker’s name to con-
tinuous paper, so as to resemble in every respect
paper made by hand.
With respect to the sizing of machine-made paper,
it is stated in the Jury Report ‘that sizing inthe vat
offers many advantages, but as a gelatine cannot be
employed without injury to the felt during the process
of manufacturing paper, substitutes for gelatine were
desirable; and in 1827 M. Canson made size of which
wax was the base, and M. Delcambre made another,
the base of which was rosin; neither seems to have
answered the purpose, for Mr. Obry’s plan of using
alum and rosin previously dissolved in soda, and com-
bining it with potato starch, which he adopted in
1827, is the method now generally followed in France
for writing and printing papers. In England, for
printing papers, the rosin size is also the one in use ;
the addition of potato starch has been attempted, but
not very successfully, probably from the quantity of
cotton rags used, which seem not readily to take the
size made with starch. For writing papers, gelatine
is still preferred in this country, and sizing is an
after process. At Mr. Joynson’s mill, St. Mary
Cray, Kent, fine writing paper is now made, sized
with gelatine, dried and cut into sheets at the rate
of 60 feet a minute in length, and 70 inches in
width. Two machines produce 25 tons per week.
The patented improvements relating to the paper-
making machine are so numerous that we cannot even
give a list of them. We may, however, notice one
or two of the most recent. Messrs. Amos and Clark,
in 1849, obtained a patent for an improved knotter
or pulp-strainer, of which Fig. 1577 is a front eleva-
tion ; Fig. 1578 is a transverse section on the lineAB
of Fig. 157 7; and Fig. 157 9 is a transverse section on
the line 0 D of the same figure—the sieve-plate being
removed. The sieve-plate or knotter, with its frame,
may be made in the usual manner. The improve-
ment consists in the mode of getting the pulp through
the plates.
a is the outer frame or box, resting on

a A f.


Fig. 1577.
the end frames b b. c is a belt of vulcanized india-
rubber, passing all round the outer frame or box, a,
and projecting some little distance within its frame;
the belt 0 rests upon a sheet d of gutta percha,
leather, or of vulcanized india-rubber,--the latter
having plies of canvas worked within it. The belt 0,
and the sheet of gutta—percha d, are held fast to
368
PAPER.
the outer frame or box a, and a water~tight junction
is made by the bar e,——bolts being passed through the
whole of them, to
keep them to-
gether. A piece
of wood f is fast-
ened beneath the
box, having a pipe
9 passing through
it, for the pur-
pose of carrying off
9 - the strained pulp
r — a to the vat. Two
ii” \ wooden boards or
Fig. 1578.


clappers it and z',
are fastened to
and beneath the flexible sheet at; and the 2 clappers
are united together by means of 2 bars j and j}, which
are bolted to them. Connect-
ing—rods attach the clapper-
bars j and j‘ to the levers
1%, t1; and an alternate rising
and falling motion is given
to them from the shaft l,
through a crank 972, on the
face of the fly-wheel n; which crank is coupled by
the connecting~rod 0 to the lever la. The radius to
the crank an can be varied at pleasure. P is a flat
horizontal spring, bolted to the framing b, and in-
tended to balance the weight of the levers ls, lel.
From the end of this spring a rigid rod 9 is pendent,
for the purpose of connecting the spring 19 with the
lever lel. The sieve-plate or knotter A, with its
frame s, is placed in the outer frame or box a, and
fastened down by the bolts r, 9", upon the elastic belt
e,-—and thus a water and air-tight joint is formed.
The pulp to be strained is admitted on the upper
side of the sieve-plates as usual; and a partial
vacuum and plenum is alternately produced beneath
the sieve-plates, by the rising and falling of the
clapper-boards la, 2'. The pipe 9' is carried into the
bottom of the vat, which is usually placed before
the “wire” of the paper-machine; and a cock, of
common construction, is usually placed in this pipe,
between the sifter and the vat, for the purpose of re-
gulating the degree of vacuum required beneath the
sieves.
In the use of smalt, ultramarine, 850., for Writing
and other papers, the two sides of the paper become
unequally tinged: .the under side being of a darker
colour than the upper surface, in consequence of the
colouring matter sinking to the lower side by the
natural subsidence of the water, or from the extrac-
tion of the water by the suction-box. Messrs. Amos
82: Clark‘propose to remedy this by employing, in-
stead of the common upper couch-roll for working
against the upper surface of the paper, a hollow roll,
perforated on its surface with a suction-box within it,
acted on by an air-pump.
It will be seen in the foregoing descriptions, that
great use is made of the air-pump in the manufacture
of paper by machinery. We believe that Mr. Dickin-



Fig. 1579.

son was the first to make this application. In 1809,
that gentleman invented a machine for making endless
paper. It consists of a polished, hollow, brass cy-
linder, perforated with holes, and covered with wire-
cloth, which revolves over, and just in contact with
the prepared pulp. The axis of this cylinder is
placed in communication with a pair of air-pumps,
and by their action the paper is formed. The film
of the pulp adheres to the cylinder during its rota-
tion by atmospheric pressure, whereby it is said to
become drier, and of a more uniform thickness than
upon the horizontal hand-moulds, or travelling wire-
cloth of Fourdrinier. By the rarefaction of the
air within the cylinder, the water is sucked in
through the cage, leaving the textile filaments so
completely interwoven, as if fitted among each other,
that they will not separate without breaking, and
when dry, form a sheet of paper of a strength and
quality depending on the nature and quality of the
pulp. The paper thus formed on the hollow cylinder,
is wound oft’ continually upon a second solid one
covered with felt, upon which it is condensed by the
pressure of a third revolving cylinder, and is thence
delivered to the drying rollers.
Mr. Dickinson has also applied to the manufacture
of paper the principle of veneering in cabinet work.
Two webs of paper are made, each by a separate
process, and by laying them together while in an
early stage, they are rendered inseparable by the
pressure to which they are subjected. This paper is
used in copper-plate printing, and by adopting a
peculiar method of preparing the pulp, and selecting
a finer rag for the web, which forms the face of the
paper, it is better calculated for taking a fine impres-
sion. In what is called protective paper, silk threads
are introduced into the body of the sheet. By vary-
ing the colour of the threads, and their distances
apart, various distinctions may be produced. A
paper of this kind is used for post-office envelopes
and Exchequer bills, as a safeguard against forgery.
The principle introduced by Mr. Dickinson of
rarefying the air below the surface of the web, was
applied in 1826 by M. Canson to the Fourdrinier ‘
machines, as already noticed, see Fig. 1576. In 1836
Mr. Brown, of Esk Mills, near Edinburgh, adopted a __
similar contrivance. His plan was, to place a rectan-
gular box transversely beneath the horizontal wire~
cloth without the interposition of any perforated
covering. In ‘1839 Mr. T. B. Crompton succeeded
in producing a uniform rarefaction under the wire—
cloth by means of a fan.
Snc'rron IV.—-S1zns or PArnRs—Pxrnn-‘currrne
Mxcnrnns.
Paper is sent into the market in various forms and
sizes, according to the use for which it is intended.
The following table contains the names, dimensions,
and wez'g/it per ream of WRITING anal Dnxwlne
Pxrnns :--
Inches. Inches. lbs.
Antiquarian..................... 52% by 30% 235
Double Elephant 39% ,, 26t- 140
33 ,, 26 100
PAPER. 369
. p _ - , Inches. Inches lbs. _ Inches. Inches. lbs: - 15s
Columbier 34% by 23 100 Large news 32 by 22 32 to 37
Elephant 28 ,, 23 72 Small news 28 ,, 21 23 ,, 25
Imperial 29%- ,, 21% 72 25 ,, 20 26 ,, 28
Super royal 27% ,, 19k 52 Medium 231} ,, 18g 24 ,, 26
Royal 23%; ,, 19 44 22g, ,, 18 15 ,, 21
Medium 22%,; ,, 17k 34 Short demy for music .... .. 20g ,, 14 25 ,, 28
Demy 1.9:} ,, 15%; 24 Copy 20% ,, 163;‘ 13 ,, 16
Extra large thick post 22%,; ,, 17%; 25 2O ,, 15 7 ,, 12
Extra large thin post 22k ,, 17% 18 Foolscap 16% ,, 131} 9 ,, 14
Extralarge bank post .... .. 22;’; ,, 17%; 13 15% ,, 12% 9 ,, 1011,;
Large thick post............... 21 ,, 16% 22 v ‘ I
Large middle post............ 21 ,, 16121 19 The last three are always made of double 8126. Print-
Large thin P0st 21 n 16%‘ 16 ing papers are usually of a yellow wove texture, and
Large bank post............... 21 ,, 16% 11 . _. .
Extmthick Post 19 15% 25 not so well s1zed as the wiltlng papers.
Thick post 19 ,, 15¢ 20 Wrappmg or pae/emg/ papers contam a large variety
Mlddle 19 n 15% 17 of sorts and sizes, such as earz‘rz'elgepapers, llae papers,
Thin post 19 ,, 15%; 14 v .
Bank post 19 15, 7 lzarol or zolm‘e-lrozoa papers, and lrozoa paper's. Then
Copy 20 ,, 16 17 there 1s blellzag paper, made of three slzes—medium,
Sheet'and-half fOOISCaP 25% v 13% 22 post, and foolscap 5 filtering paper, of the size of
Sheet-and-third foolscap 22 ,, 13%; 20 ' - ¢ -. .
Extra thick ,0 018 0 ap 16, 13k 18 double-crown, 1s thick, and woolly 1n texture. Tzssae
- o n Q o u v u _ g ,’ . , n
Foolscap 161, ,, 131,L 15 ' paper is made of the size of crown, double and smgle,
IIIIIOOOQ'IIII-I IIIO'II'IIIUOII ,, a
DRAWING papers are not made smaller than demy,
and are made up into reams flat: WRITING papers are
not made larger than double elephant, and seldom
larger than imperial, and are most commonlyr folded.
Laid papers are distinguished by certain water-marks;
thus post has a bugle-horn; copy, a. fleur-de—lis ; fools-
cap, a lion rampant or Britannia; and poll paper has
the English arms. These marks enable any one to
determine the original dimensions of the paper, how-
ever much it may have been reduced in size.
is no water-mark in wove papers. Post papers are
not usually sold in the folio; but are cut in half,
folded, and ploughed round the edges, forming qaarz‘o- "'
r‘ hand, of the exact size indicated; but if made by the
post, or common letter paper. When this is out and
again folded, it forms octave-post or aole-paper; an- ‘
other folding forms 16mo. or small aoz‘e; and so on up
to 64mm. post, or lilliputian note-paper. After plough-
ing, the edges may be left plain ‘or be gilt or blacked.
Papers folded the broadest way are named lroaolfolz'o,
and the narrow way, leap folio.
0r lroacl gaarlo, oolaoo, &c.
PRINTING papers include PLATE papers, or those
used in copper-plate printing. The latter are of the
same size, weight, and quality as the drawing papers,
but difi'er from them in being soft and absorbent, the
sizing being omitted in the manufacture. Plate
papers are not made smaller than medium, which is .
the size required for the plates of a demy book.
When the plates are to be coloured, drawing paper
is used, and is termed fiarelplaz‘e, to distinguish it
from the former, or soflplale. If plates printed on
soft paper require to be coloured, the paper must be
sized with a clear solution of isinglass. For taking
proofs of engravings, a paper of Chinese manufacture,
known as Iaelz'a paper, is used. It is very soft and
flexible in texture, which enables it readily to take
every line of the engraving; it takes the ink well, and
dries more rapidly than any other paper. It is im-
ported in sheets 52 inches long and 26 inches wide:
the weight varies. The other papers in this class are
given in the following table; but the weights and
sizes vary with the manufacturer ;~—'
VOL. II.
There is also leap 1

copying letters written with copying ink [see COPY-
ING MACHINE]. Ia'llress is a kind of smooth cartridge
paper, used only in the manufacture of cards. A
thick purple paper, used by grocers, forms a distinct
class, under the title of sugar-clues. There is also a
class known as Maae/zesler papers, made large and
i coarse for packing; there is also slzeal/a'ag/ paper, for
the‘ use of ship builders, and lip paper, for hatters.
i There are also eoloarerl papers of two distinct kinds;
There 1
one made by colouring the pulp in the vat, and the
other kind made from white paper. Marble papers
- have been described under MARBLING.
Many of the papers above enumerated are made by
machine, the roll of paper has to be out to the re-
quired dimensions. In order to do this with precision
and expedition, various cutting machines have been
contrived; a few. of which we now proceed to de-
. scribe.1
One of the simplest of these machines is that by
Mr. John Dickinson, an elevation of which is shown
in Fig. 1580. The roll of paper, r, to be cut, is sup—
,2"
‘N
v--.
M
La»j .2

/e
1;—
rpm




Fig. 1580.
ported by its axis upon an iron frame ; and from this
roll the paper in its breadth is passed over a con-
ducting drum, el el, turning on its axis in a frame;
and after passing over a small guide roller y, it is
passed through a couple of drawing or feeding rollers
j, which conduct it over the table 2f, where it is out.
Attached to this table is a number of chrsel-edged

(1) Other forms of paper-cutting machines are described in Ure’s
Dictionary of Arts and Manufactures, and also in Hebert’s
Mechanic’s Cyclopadia.
BB
3'70 *
- PAPER.
knives ls ls, placed at such distances apart as the
dimensions of the sheets of paper require. A set of
circular cutters e e, mounted in a swmg-ing frame s,
are~arranged so as to meet the edges of la la, and form
pairs of shears therewith. The length of paper being
dragged forward by workmen over the table 25, up to
the-stop p, the cutters swing forwards, and the paper
is. cut- into four separate sheets, The frame .9 is, hung
upon an elevated axle, so that in swinging the cutters
may. move in a nearly horizontal line: this frame is
made to swing backwards and forwards by an eccen-
tric, ., or crank,‘ fixed upon a horizontal shaft, extend-
inglover the drum cl,,considerably above it, and made
to revolve by any convenient power. The work-people
draw. the paper forwards up to the stop p, in the
intervals between the swinging of the frame.
The late Professor Cowper obtained a patent in
1828 for a paper-cutting machine, the details of which
willl be understood by referring to Fig. 1581. The
paper to be cut is first conducted by hand from the
reeliR, up the inclined plane p; it is then seized by
endless tapes extended upon rollers. These tapes
convey the paper to the roller 0, which bears against
the roller 0', by means of weighted levers acting on
the‘ plummer blocks which support its axle. The
second roller 0', is furnished with several grooves for
receiving the edges of the circular cutters k, which

Fig. 1581.
divide the paper lengthwise. A narrow rib of leather
is fixed round the edges of one or both the rollers
e 0?, to preventtheir actual contact, and to allow the
paper to pass between them without wrinkling. The
paper is then passed, by means of the tapes, from the
first roller 0,, over the second roller 0', and then under
a pressing roller'c, during which progress the paper
is, divided longitudinally by the circular cutters la,
fixediat such distances apart as the width of the sheet
of paper may require. ' The strips of paper thus
formed are conducted from under the pressing roller
ee, by. means of tapes to the roller 6, when the strips
descend to the knife which‘ cuts them transversely.

This knife, shown by the black line e, is horizontally
placed in the frame at f; and is moved to and fro by
a jointed rod j, connected with a crank on the axle
of the pulley :r. Opposite the knife, and extending
across the frame, is a flat board cl, furnished with a
groove for receiving the edge of the knife. As the
paper descends from the roller 6, and passes against
the face of this board, and as the carriage with the
knife advances, two small blocks mounted upon rods
with springs ss, press up against the paper, and hold
it firmly to the board el, while the edge of the knife
passes through the paper into the groove. The edge
of the knife is made on this principle :——The point of
a penknife is easily pushed through a sheet of paper,
while a straight edge does not pass through without
considerable pressure. The knife was therefore made
with a series of points, which separated at each cut a I
row of sheets, which as the blocks receded fell down,
and were collected on the heap below.
The power for moving this machine is applied to
the axle on which the pulley a: is fixed; a band ll
passing from this pulley over tension wheels drives
the wheel 20, fixed to the axle of the knife roller e’ ;
by the motion of this roller, the web of paper is
moved forward, but the other rollers are driven by
friction of contact. The rotation of the crank on
the axle of a", by means of the crank rod j, moves the
carriage f with the knife to and fro at certain inter-
vals; and when the spring blocks s s press against the
grooved board 6!, they slide their guide rods into them,
while the knife advances to divide the sheets. By
varying the diameter of the pulley w} the rate of ro-
tation of the three conducting rollers e e’ a can be
varied so as to cause a greater or less length of paper
to descend between every two motions of the knife~
carriage, and thus the length of the sheet may be
regulated at pleasure. '
While the paper is momentarily held by the blocks
s s in order to be cut, the descent of the paper must
be for that short space of time suspended. It does
not, however, require that the longitudinal division
of the paper should be interrupted; hence the fourth
roller 5, which hangs in 'a lever l, is made to rise just
at that point, so as to take up. the amount of paper
delivered, and to descend when the. springs at s_ s re-
lease the paper. This is brought about by means of
the rod 9*, attached to the crank on the shaft of the
roller a‘, and to the under part of the lever l ,- this
lever hangs loosely on the axle of the knife-roller e’
as its fulcrum, and vibrates with the under roller.
In consequence of the construction of the hori-
zontal knife, two of the edges of the paper are left
rather rough: this is of no consequence when the
edges of the paper have to be ploughed afterwards.
It is, however, an objection; and as other machines
were introduced, Cowper’s ingenious arrangement
ceased to be used, except as a model for other men
to improve on.

(1) The groove of this pulley is made of wedge-formed blocks
passed. through its sides, and meeting each other in opposite direc-
tions, so that on drawing out the wedges a little, the diameter of
the pulley is diminished, and by pushing them in it is increasedl
The tension-wheel below keeps the band always tight.
PAPER.
371'
Paper-cutting machines now usually form part and
parcel of the paper-making machines, so that instead
of winding the paper upon a reel as it leaves the
steam drying cylinders, and removing this reel as it
becomes filled to a separate cutting machine, the reel
is dispensed with altogether, and the paper as it
leaves the last of the steam cylinders, proceeds at
once to the cutting machine. This economical ar-
rangement was, we believe, first made in Mr. Tow-
good’s machine, patented 15th March, 1832. In this
machine, the longitudinal section of the paper, as it
comes from the drying apparatus, is performed by
circular knives as before. In order to cut it into
lengths, two conical drums are arranged, one in con-
nexion with the drying apparatus of the paper-
making machine, and the other with the cut-
ting machine. The bases of the cones are set
in opposite directions, and a strap or other
connector is passed over each. From the shape of these drums, the strap may be easily " .
regulated by hand. The roller on which the
paper is received from the drying apparatus
is connected by a crank with a measuring
wheel, set with teeth, and regulated by the
action of the crank, so many teeth to such a
measure. The paper being already cut longi—
tudinally, is, if necessary, brought out on its
feeding roller to another connected with the
action of the measuring wheel, and it is there pressed
down into a loop, and brought in contact with the-
transverse cutter, so placed as to pass rapidly and re-
gularly across its breadth, dividing it into the length
prescribed by the measuring, when the paper falls
into a receiver set on purpose, and is removed in the
proper lengths to a heap. In the meanwhile the feed-
ing roller retains its hold, and by a repetition of the
process, the next length is brought to the knife in the
same manner. The action is commenced by a winch
turned by hand or otherwise.1
The improvements which have of late years been
effected in paper-making machines, admit of their
being worked at a much greater velocity than hereto-
fore, and hence great inconvenience has been expe-
rienced with the paper-cutting machines in general
use, as they cut the sheets of paper into irregular
lengths, when working at a speed necessary to keep
up with the paper-making machine. To overcome
this difficulty, Messrs. Amos & Clark, in November
1849, patented a machine, which is next to be de-
scribed.
Fig. 1582‘ shows a side elevation of this machine;
Fig. 1583 is an elevation of the opposite side thereof;
Fig. 158% is an end view, taken at the back part of
the machine, where the paper is delivered; and Figs.
1.585, 1586 show the gathering-roll, and the action
of the parts in connexion therewith. Motion is
given to this machine by the shaft A, from any prime
mover; and the shaft B is driven by a strap passing
round the conical drums C and D, mounted respec~
tively on these shafts. The shaft B carries the crank

(1) Repertory of Patent Inventions-

a, the eccentric b and b’, and the rigger or band-
wheel E; which latter is for the purpose of driving
the fly-wheel and thereby steadying the motion of
the machine. This rigger E has a plate, with staple- _
headed projections cast on its outer side; and
through these projections the crank-arm z passes, and
is retained in any required position by the set-screws
dd. A means is thus presented of altering the
radius of the crank to u I
admit of sheets of -' '
paper being cut to
any required length.
The rotary motion of
the shaft B gives a
reciprocating motion
a
.
, \ 2






En’ .
I
“P
kt!
_



Mr,
00 “la!
w/




Fig. 1582. SIDE Bnr-zvA'rion.
to the gathering—drum F, through the connecting-rod e,
which is coupled to the crank-pin of the crank-arm z
atone end, and to the lever f at the other; which
lever is keyed upon the shaft of the drum F. Above
the gathering-drum E the rollers g and ‘a’ work in










Fig. 1583.
smn ELEVATION orrosr'rn PIG- 1582.
hearings in the cross-head e. An alternate rising and
falling motion is given to these cross-heads and
rollers by the excentrics b and b’ on the shaft B,
through the connecting-rods z and z’, the levers b b,
and the vertical bars 2' z' ; which bars work through
guides fastened upon the side-frames of the machine.
A presser n is suspended to the side-frames of the
machine, by the right-angled levers J and J’; and an
B B 2
372
PAPER.
alternating motion is given to it, in order to make it
approach to and recede from a stationary presser-

.Fz'g. 1584.
‘END VIEW.
board T, (see Fig. 1585,) and lay hold of the paper as
it descends from the drum F, to be divided into sheets
by the cutters. When the levers k descend, a pin k
on each side of the machine presses upon the forked
ends of the connecting-rods l, and thereby causes the
end m of the right-angled levers J and J’ to descend,
and carry the presser H away from the presser-board
1‘. As the levers l. ascend, the presser H is brought
back by the springs n (one placed on each side of
the machine, and connected to the presser by the
connecting-rods o). I is the fixed horizontal knife,
fastened to the side frames; and the movable knife
K is suspended to the side frames by the rods r and 1?’.
Motion is given to this knife by the crank a, the con-
necting-rod g, and levers r r’, and the connecting-
rods as’. The combined motion of these rods and
levers admits of the movable knife remaining nearly
quiescent for a given time ; then, speedily closing on
the fixed knife I, it moves over the edge thereof,
cutting whatever may be between the knife-edges in
the same manner as a. pair of shears. The sections
Figs. 1585 and 1586 show more clearly the gathering-
drum F, the rollers g and g’, the guide-roller t, the
movable presser H, and a fixed presser-board T,
which forms with H the press for holding the paper.
The paper to be cut passes over the front rollers
1 and 2, between the circular knives 3, and beneath
the tension'roll 4, in the- usual manner. It then
passes over the gathering-drum F, and beneath the
rollers g and g’ (which press upon the drum when
the paper is being carried forward); and then under
the guide-roll t, and between the pressers H and T,
which, during the progress of the paper, are open to
receive it.
The operations peculiar to this machine will be best
understood by reference to Figs. 1585 and 1586 :—
thearrow, Fig. 1585, shows the direction the paper is
travelling. When the crank-arm z arrives at the line
of centres (as shown at Fig. 1583), the pressers H
and 'r are closed, the rollers g and 9' have begun to
rise, and the motion of the gathering-drum r‘ is-

reversed ;~—-it being made to turn in the direction of
the arrow, Fig. 1586. During the time the pressers


Fig. 1585'. Fig. 1586.
H and T are closed, the movable knife K is drawn
inwards, and the length of paper hanging from the
pressers is cut off. As the gathering-drum makes its
backward movement in the direction of the arrow,
Fig. 1586, it smooths out the paper upon its surface,
which is now held between the pressers H and 'r;
and the tension-r0114: takes up the slack in the paper
until the motion of the drum is again reversed. Mo-
tion being now communicated to the drum F, in the
direction of the arrow, Fig. 1585, and the rollers g 9’
being again brought into their lowest position, a
further length of paper will be drawn forward, ready
in its turn to be laid hold of by the pressers, and
finally cut ofi' into a sheet. When it is required to
cut a short sheet, to bring the water-mark more into
the centre of the sheet of paper, the action of the
tension-roll A is stopped by the pall a being brought
into contact with the ratchet-wheel o:—-this is effected
by the handle a). The handle .2: (shown in Figs. 1582
and 1583) is for moving the strap on the conical
drums; and the board 3/ is merely a stage, to enable
the attendant to pass the paper through the machine
more readily.
Sncrron V.-~Hor-rnnss1nc, Gnxznve, AND FINISH-
ING—STATISTICS.
Fine papers are in some cases hot-pressed and
glazed. In hot~pressing, a number of stout cast-iron
plates are heated in an oven, and then put into a
screw press, in alternate layers with highly-glazed
pasteboards, between which the paper is placed in
‘open sheets; and the hard polished surfaces of the
pasteboards, aided by the heat and pressure, impart
that beautiful appearance which belongs to hot-pressed
paper. A yet more smooth and elegant surface is
produced by the process of glazing. The sheets of
paper are placed separately between very smooth clean
copper plates. These are then passed through rollers,
which impart a pressure of from 20 to 30 tons. After
three or four such pressures, the paper is called rolleel,
and sometimes also fiat-pressed; but if passed more
frequently through the rollers, the paper acquires a
higher surface, and is then called glazed. See Cann-
BOARD.
In glazing papers with copper plates it has been
found that, through the curvature of the rolls, the
pile of paper between the copper plates is sometimes
disturbed, and the edges become frequently blackened
in consequence. To obviate this defect, Messra'
PAPER.
373
Amos 8r Clark‘ employ rolling-machines of ' the con-
struction shown at Fig. 1587. This figure shows, in
section, 3 pairs of hollow pressing rollers, but more
or fewer pairs may be used, if required. Between
these rolls, which are suitably mounted, a wrought-
iron plate, for carry- '
.1 [1.1%
-
ca’
'1 _

A '
ing the pile of paper
to be glazed, is made
to traverse, by means
of a reversing mo-
tion with which the
rolls are provided.
a, 6, 0, ol, e, and j,
indicate the 3 pairs
of rolls; g, is the
metal plate; and l, i, show the piles of paper, with
their layers of copper-plates or glazed boards, as
usual. j, ls, l, are 3 wheels, keyed upon the rolls,
and driven by the pinion m (from any prime
mover) ;-—the wheel j is keyed on the roll a, the
wheel is on the roll e, and the wheel l on the roll 0.
The pinion m works into the wheel is. On the oppo-
site side of the machine (but not shown in the draw-
ing) other wheels, of similar diameters, are placed on
the rolls, 5, el, and f; and a similar pinion to m, and
keyed on the same shaft, works into the wheel keyed
on the roll f ,' by which arrangement the whole of the
rolls are driven in the proper direction.
The general introduction of steel pens has increased
the demand for smooth papers, and has led to improve-
ments in finishing them. By passing writing papers
in long lengths through naked rollers, the latter soon
become indented. A better plan is to pass the paper
several times through a calender, having an iron roller
at the top and bottom and a paper roller in the middle,
the iron rollers being slightly heated by steam. It is
remarked in the Jury Report, that “ there is no diffi-
culty in glazing papers in long lengths, provided care
be taken to obtain very true rollers.1 A thin ductor
blade should be fixed in a proper position, to detach
the sheets as they pass through, as the electricity
which is developed causes them to adhere to the
cylinders, particularly where rosin size has been
used.”
_ In drying‘machine-made papers, more attention is
now paid to the surface than formerly. Messrs. Amos
and Clark remark, that “'in heating the drying-cylin-
ders for drying the paper by steam, it is known that
this operation is better effected when a varying tem-
perature is given to each cylinder: thus the cylinder
which receives the paper first is preferred to be cooler
than the following one, the second cylinder cooler



(l) A method of making cast-iron rollers truer than is possible
by turning in a lathe, was invented by Mr. Thomas Barratt of St.
Mary Gray, and is described in the third volume of Holtzapfi‘el’s
Mechanical Manipulation. It consists in merely grinding the
rollers together with water, without the application of emery or
any other grinding material. The grinding action appears to be
chiefly due to the small particles of cast-iron rubbed off by the
friction, and which serve as the abrading powder. The grinding,
which lasts several weeks, may be expedited by using the same
water repeatedly over again; but towards the conclusion, when
high finish is required, clean water is alone used. For a very
high'finish, oil instead of water is used towards the end of the
process.
than the third, and so on. The character of‘ the
paper, when dried under such circumstances, ap—
proaches more nearly to the ‘ loft-dried paper,’-—it
being tougher in quality, and without the harshness
of machine-made papers when dried in the usual way.
The usual mode of regulating the steam pressure in
the cylinder‘has been by the common steam-cocks;
but, as this is attended with much uncertainty, they
have patented a pressure-regulating valve, for regulat-
ing at pleasure the pressure in the cylinders. This
valve is shown in sectional elevation at Fig. 1588,
wherein A is a cylinder, having a
piston 13, nicely ground and fitted,
working within it. o is the piston-
rod, passing loosely through the
crown of the cylinder, and carry-
ing a weight D. n is the valve-
seat, being a hollow cylinder,
having four or more ports or
openings in its periphery; three
of which ports are shown at a a a.
F is the valve, being a cylindrical
ring of metal, which is made to
slide on the valve-seat n, by means
of the connecting-rods G and G’,
which couple it with the piston 13
by the cross pin 6. H is a cylinder,
or steam—box, having the upper
cylinder A bolted to it; and the

Fig. 1588.
' cylinder, or valve-seat E, passing through it, is secured
in its place by the nut e. The valve-seat n is at-
tached by the pipe J, to the pipes leading from the
steam-boiler: and the pipe I leads from the steam -box
11 to the drying-cylinder. One of these regulating
valves is required for each drying-cylinder. When the
weight D is in its lowest position, as in the figure, the
sliding-valve r is also at its lowest position, and the
ports aaa are open ;——thus allowing the steam to
pass from the boiler into the drying-cylinder in the
direction of the arrows. When the pressure in the
drying-cylinder, and in the steam~box H, exceeds the
resistance oifered by the weight 1) to the piston 13, the
'piston will be raised by the pressure of the steam,
and thereby carry up the sliding-valve F, and close
the ports aaa to the proper degree for the pressure
required’, which is when that pressure and the resist-
ance from the weight 1) are in equilibrium. When the
piston B rises suificiently to bring the surfaces 0 e ' of
the sliding-valve F in contact with the surfaces cl cl’
of the valve-seat E, the openings aaa will be closed,
and no steam can pass from the boiler through the
pipe I to the drying-cylinder in connexion therewith.
By placing weights of different sizes upon the pressure-
regulating valve of each drying-cylinder, any required
pressure of steam can be maintained therein.” 2

(2) The patentees state that this regulating valve may be ap-
plied to various purposes,~—as, where steam of any high or varying
pressure is required to be reduced to an uniformly low pressure.
The valve will be also useful in reducing the pressure of columns
of water,—as when attached to a high—service main,—and obtain-
ing an uniformly low pressure. The pressure of air, gas, and
other fluids, may be in like manner regulated by this valve when
required.
374
PAPER—PAPER-HAN GIN GS.
As an improvement in themanul'acture of paper‘
sized by the machines now in use, the patentees
propose to conduct the web of paper, after it has
been either partially or completely dried, through a
trough .of cold water, then to pass it through a pair
of pressing-rolls, and afterwards to dry it on reels, or
over hot cylinders. The paper thus treated will be
found to “bear f’ much better, and admit of erasures
being made on the surface of such paper, and written
over, without the ink running. in the way it does
when the paper is sized and dried in the usual
manner. -
It has been found that when paper is dried, after
sizing, by the drying-machines - in present use, the
paper is very harsh, and, until it stands for some time
to get weather (as it is technically termed), great
difficulty is experienced in glazing the paper. This
inconvenience is proposed to be overcome by passing
the paper partially round a hollow cylinder, through
which a small stream of cold water is made to run.
By this means the heat in the paper is carried off,
and the paper is rendered more tractable, and brought
to a proper state for undergoing the glazing operation.
It is stated in the Jury Report, that “in England
writing papers are sized with gelatine, and are stronger
and harder'than those of other countries; they are
also cleaner, generally better put up, and show greater
care in the manufacture, than those of France and of
other countries.‘ The old cream-laid papers, now so
fashionable in England, were, re-introduced by Messrs.
Hollingworth, of Turkey Mill, Kent, a. few years
since, and they are still preferred for letter and note-
paper. The thinner post writing papers, however,
are much better manufactured in France, Belgium,
and other parts of. the continent, than in England.
Those exhibited- fromiAngonleme in France, and
Heilbronn in‘Germany, are the best; those made in
Belgium are not‘ sufficiently hard-sized. Notwith-
standing the high protective duty of 451561. per pound,
a considerable quantity of these thin writing papers is
imported into England. The white of the letter-
papers of France, Germany, and other foreign coun-
tries, is of great purity and beauty : and these papers
being sized in the vat with farina, in addition to
rosin-soap, instead of gelatine, they are less greasy
under the pen, and consequently can be written on
more freely than those which are sized with animal
size;~they do not, however, bear the ink so well.
English printing papers generally maintain a supe-
riority over those of foreign countries; and in
drawing papers and strong account-book blue-laid
papers, England stands unrivalled. Tinted printing
and drawing papers, formerly made exclusively in
England, are now‘produced by most foreign paper-
makers, who also make the tinted writing post papers,
lgng out of fashion in this country. M. Obry of
Prouzel exhibited well-made black papers for wrap-
ping cambrics, lace, 850. Black papers of the same
kind were made in Ireland and Manchester more than
twenty-five years ago.”
The following is an account of the number of
paper-mills in England, Scotland, and Ireland, with

the number of ‘beating-engines" employed‘; also the
amount of duty charged on paper, the quantity im-
ported from various countries, and the amount ex-
ported from Great Britain in 1850 :—
England. Scotland. Ireland.
Number of paper mills ....... .. 327 51 37
Number of . beating engines... 1,374 286 86
lbs. lbs. lbs.
Paper charged~ with duty .... .. 105,712,953 28,600,019 6,719,502
Amount of duty £693,741 £187,687 £44,096
Paper Imported—
Printed, painted, stained, 01‘ sq. yrls. sq. yds.
hangings 342,746 470 --
lbs. lbs.
Other kinds..................... .. 267,162 53 —-
Amount of duty £5,607 £5 —-
Paper Exported-—
sq. yds. sq. yds.
Printed, painted, or stained .. 1,155,022 163,164 ——
lbs. lbs. lbs.
Other kinds 6,568,268 1,040,555 9,948
Amount of drawback paid £43,934 £6,946 £60
It appears from a parliamentary paper, published
9th March, 1852, that on the previous 18th February
the number of paper-mills at work in England was
304:, in Scotland 418, in Ireland 28; making 380.
There were 1,616 beating-engines at work, and. 130
silent.
The amount of duty charged in 1850, shows the
enormous amount of 62,960 tons weight of paper
produced in Great Britain in one year. The annual
value of paper manufactured/in this country is esti-
mated at‘two millions sterling.
PAPER-HANGINGS. The fashion of covering
the walls of apartments with decorative paper-hang;
ings, or, as the French call them, pajoz'ers paints, has
been derived, like paper-making, from that ingenious
people, the Chinese. The art of making paper-hang—
ings has existed among them from time immemorial,
and England, it is said, was the first country to imi-
tate the specimens of their skill which had been
imported hither.
To this art we are indebted for much of the appear-
ance of comfort and respectability which prevails in
the houses of the middle and lower classes of this
country. The wealthy might, and often do, adopt
other modes of ornamentation, but for the professional
and working classes, paper-hangings, varying in price
and in style, afford the means of clothing the walls of
their dwellings cheerfully and pleasingly, and in a
more or less elegant manner according to the means
of the owner. Paper-hangings, even of the lowest
price and quality, may yet, by their simplicity and
good taste, greatly enhance the beauty of a cottage,
and increase the sense of comfort in its occupants.
For there is no question but that the feeling of com-
fort is largely influenced by the colour and fitness of
the objects around us. Who has not felt relieved on
entering a room with a cold northern aspect, to find
the walls covered with rose-coloured, or crimson paper-
ings, or with paper in which the warmer tints predo-
minate? and who has not experienced, on the other
hand, a sense of coolness, on finding a room with a
bright southern aspect, judiciously papered with an
admixture of a. cold colour, such as a bluish green,
(in contradistinct-ion to the bright yellowish green,
PiiiPER-HANGINGS;
375
which gives a‘ sense of heat rather than of cool-
ness) P _
The apparent warmth or coldness of a room is not
the only point on which it is influenced by the nature
of its paper-hangings: its apparent size and height
are increased or diminished by the same means. Papers
of a large pattern greatly reduce‘ the apparent size:
those of a large and flowing pattern the height; a
paper in which perpendicular lines predominate,
although the pattern be large, does not so much
affect the apparent height. To cover a small room
with paper of a large pattern is a great mistake; a
still worse mistake is to paper the ceiling, as is some-
times done on the continent.
The best effect is produced by using papers in
which the pattern and colours are quiet and harmo=
nious, and do not strike the eye. The walls of a room
are like the back- ground of a picture, and should be
so treated as to relieve and set off the objects in front
of them, and to give repose to the eye. A paper
presenting—sudden contrasts in colour, and strongly
marked lines in the pattern, forms the worst possible
back-ground for pictures, and the most unfavourable
accompaniment to furniture, draperies, and objects of
taste. The spotty effect of such a papering interferes
with all the minor objects inthe apartment, and gives
an unpleasant and bewildering effect. Modern paper-
hangings are frequently made to represent columns,
friezes, _ pilasters, &c., dividing the room into com-
partments. Notwithstanding the beautiful execution
of some of these papers, they cannot be recommended
as in good taste. The introduction of real objects of
the kind would be an absurdity in a situation Where
their support is not needed; therefore why should
we have sham pilastres, 860.? The introduction of
flowers and conventional forms for the ornamentation
of our walls is not unnatural; consequently their
imitation does not involve an absurdity. It was
suggested, a few years ago, that paper-hangings
might be made instructive, as well as ornamental, by
the introduction of poetical and other sentences of a
moral and religious kind. In former days it was not
uncommon to have the walls adorned with tablets,
containing sentencesv from various authors, for there
are drawings still extant of those which ornamented
the apartments of Sir Nicholas Bacon. It has there-
fore been thought desirable that paperings of a similar
kind should be prepared, with compartments, repre-
senting tablets, in which appropriate mottoes should
be printed in the old English or German characters.
This custom would be liable to many abuses, arising
from the defective tastes of those who had the choosing
of the mottoespbut perhaps this is not a sufficient
reason why we'should discard a practice which might
be productive of useful results. '
The early method of making paper-hangings was
by 85622027151251, as that mode of painting was called, in
which a piece of pasteboard, or sheet-metal, with pat-
terns cut out in it, was laid on the paper, and'water-
colours were applied with a brush to the back of the.
pasteboard, so that the colours were delivered through
the openings, and formed the patterns upon the paper.

When the first series of colours had become dry, an-
other might be applied with a second piece of paste-
board, and so on, until considerable variety was
attained, but at much cost of time and trouble. These
processes were afterwards superseded by those of the
calico-printer, which were successfully applied to the
manufacture of paper-hangings, the pattern being
engraved on wood-blocks made from the pear-‘tree or
sycamore‘, and the coloured designs printed from them
by hand, on papers previously prepared, by laying on
them a uniform ground of some earthy colour thick;
ened with size. I
The progress of improvement in this manufacture
was, however, greatly checked in England by the
high protective duty of one shilling per square yard,-
which existed up to the year 1846, and which almost
entirely excluded the works of foreigners. Thus our
own manufacturers had little stimulus to improve;
ment, and were unable‘ to profit by the French modes
of manufacture, which progressed‘rapidly. In the"
above year the duty was reduced to twopence, since
which time great progress in the manufacture has
been made in this country, both' as to style and worki
manship. -
In printing by hand, as many blocks are required
as there are shades and varieties of colour. In the
Great Exhibition there were to be found specimens‘-
of decorative paper-hangings requiring a large num-
ber of blocks to produce the pattern. The labour‘
and skill bestowed on some of these were immense;
but the effect was not always proportionally good. In
fact, the attempt to bring as many colours as possible
into one composition is very much to be deprecated.
The result may astonish those who are aware of the‘
number of the processes adopted, but it will be seldom'
pleasing to persons of good taste;
The blocks of the paper-'lianger, like those of the
calico and floor-cloth printer, consist of engraved
pieces of pear-tree or sycamore, mounted-en poplar or
pine-wood. Each has 41 pin-points at lithe corners,
which make g-uidamarks on the paper for placing the
succeeding blocks in the same spot. These blocks are
pressed on the sieves of colour, and applied in suc-
cession with some force to the paper. These sieves
or drums are covered with calf’s-skin, and float in a‘
tub of water thickened with parings of paper from the '
bookbinders. The drum is- kept uniformly covered
with colour by a child, who takes up a‘ small quantity
on a brush, and distributes it afresh over the surface
after every application of the block. The workman,
in pressing down the 'block charged with colour on
the surface of the paper, employs a lever to increase
the power of his arm, the child drawing away a por
tion‘ of the paper at intervals across a wooden trestle,
. —-hence the name of tireur'(drawer) given to the child.
When the piece‘ has received one set of coloured im-
pressions', the workman, assisted by the drawer, hangs
it up to dry, on poles near the ceiling, to which hooks
are attached. If the paper is of the description
called flock-paper, the pattern is first printed in size,
then with a preparation of varnish, and before this is
dry, the coloured flock prepared from wool -is sifted
376
PAPIER MACIIE-JPARAPET.
over the paper, and adheres to the varnished parts.
The preparation of the flock is as follows :—-When
obtained from the woollen cloth manufacturers it
consists of particles cut off by the shearing machines,
and may be either white or coloured; if white, it has
to be secured and dyed to the proper tint. It is then
stove-dried and ground to a fine powder. This is
further prepared by sifting to different degrees of
fineness in a bolting—machine. It is then placed in
a large chest, or team, whose width and capacity are
such that the child can draw the printed paper into
it by degrees at its full width, and sprinkle the flock
thereon, When about 7 feet of papering have been
thus drawn in, the child shuts the lid of the drum,
and beatswith rods on the bottom, which is made of
tense calf's skin, and is elevated 2 feet from the floor by
means of strong supports. This beating on the drum
raises a cloud of flock inside, which, as it subsides,
falls uniformly on the paper. The chest is then
opened, the paper is inverted, and lightly tapped to
detach loose particles. Gradations of colour in the
flock are afterwards produced by applying to the sur-
face, when thoroughly dry, lighter or deeper shades
in watercolour or in distemper. Gold-leaf is applied
to paper-hangings in the same way as to wood, and by
means of a preparation washed over it, is made more
durable than formerly, and better able to resist damp.
, A great change has been made in the manufacture
of paper~hangings during the last ten years, by the
introduction of machine printing. By means of steam-
power, an endless roll of paper, and artificial drying,
the system of surface-roller printing in several colours,
as described under CALICO-PRINTING, is now success-
fully applied to paper-hanging. Papers thus produced
are not equal to those done by hand, but they can be
so cheaply produeed,tha_t ,they command an extensive
sale." ~Machine, printing has not yet succeeded with
papers in which glazed or satin grounds are required.
In the Great Exhibition were specimens of machine-
printed paper showing 14: colours :. others showing
20 colours, made by 14 rollers. It is stated that
each machine is capable of printing from 1,000 to
1,500 pieces per day. It is estimated that in 1851
there were produced in Great Britain, 5,500,000 pieces,
of the value of 400,000l.
PAPIER MACHE. Articles so named are pro‘
duced either by pressing the pulp of paper between
. dies, or by pasting paper in sheets upon models. The 1
articles when dry are varnished, j apanned, and orna~
mented. By the first method, a variety of cheap ar-
ticles is manufactured in Paris; the materials for the
Pulp. Viz. paper and paste, being ‘supplied by the bill-
stickers, whose bills having served the purposes of
advertisements by day, are, by night, pulled down and
taken to the factory, masked in water, and pressed ill
moulds. The second method is the superior of the
two, and is thus conducted at Birmingham z—Paper
of a porous texture, saturated with a solution of flour
and glue, is applied to an iron, brass, or copper mould
of somewhat smaller size than the object required:
repeated layers of this paper are put on with glue, a
drying heat of 100° being applied after every new, _’

coat. When a sufficient thickness is attained, the
shell is removed from the mould, and planed and filed
to shape. About 10 layers are used for an ordinary
tea-tray; more or less for other articles, according to
circumstances. A tar-varnish mixed with lamp'bla-ck
is next laid on, and the article is stoved.~ Several
coats of varnish are added, with a stoving after each.
When suificiently covered with this preparation, the
inequalities are removed with pumice-stone, and the
artist applies the ornament in bronze-powder, gold, or
colour. Several coats of shell-lac varnish are then put
on, and the article is stoved at a heat of 280°. The
article is polished with rotten stone and oil, and
brought to a brilliant surface by hand—rubbing.
A favourite material for ornamenting papier-maché
articles is mother-of-pearl, and the artist cannot cer-
tainly be accused of want of liberalityin the use of it.
In the Great Exhibition the gaudy, over-ornamented
papier-maché articles in the English department pro
duced a painful efiect, and clearly proved that the art
of design in this material is unknown in this country:
the impossible landscapes, the mother-of-pearl rivers
and moonlights, might have excited a smile, had not
the display told of a vast amount of labour and inge-
nuity thrown away. Some very common articles in
japanned ware, from Japan and China, were in excel-
lent taste, showing, as the Jury Report well remarks,
that “vulgar forms and bad ornament are not neces-
sarily connected with cheap manufacture.”
The largest manufacture of papier maché in Eng-
land is that of Messrs. J ennens and Bettridge, at
Birmingham, whose factory, which is open to the
public at stated times during the week, we have had
much pleasure in visiting. Among the endless variety
of objects exhibited by them in this material were
tables, chairs, screens, work-boxes, inkstands, port-
folios, and a piano‘. Many of the articles were orna-
mented in good taste, but the great fault of over-
ornamentation was evident in nearly all cases.
Papier maché used for architectural purposes is
prepared by laying sheets of brown paper one over
the other, with a coat of glue between every two
layers. This mass of paper is pressed into a metal
mould of the ornament required: the moulded paper
being trimmed to shape, a composition of the pulp of
paper mixed with rosin and glue is put into the mould;
the paper is again inserted and pressed upon the pulp
composition which adheres to it, and produces a sharp
well- defined ornament.
Carton-pierre ornaments are also composed of the
pulp of paper mixed with whiting and glue, pressed
into plaster piece-moulds backed with paper, and
when sufiiciently set, hardened by drying in a hot
room. Carton-pierre is stronger and lighter than
plaster-of-Paris. '
PARACHUTE._ See Annosratrron.
'PARAFFINE. See Introductory Essay, pp. lxxxiii.
and lxxxv. _
PARAPET (Italian pamper/‘to, from the Greek
mipa, against, and the Italian petto, the breast), a low
or breast-high wall or fence, used as a protection on
bridges, terraces, platform roofs, &c.
PAROHME NT—PA RING-KNIFE.
377
' PARCHMENT, the skin of an animal prepared for
writing on. The name is from the Latin Pergamena,
from Pergamzrs, the reputed place of its invention.
Eumenes II. king of that place (who reigned 13.0.
197—159), has the honour of the invention, he being
stimulated thereto by the prohibition of the export
of papyrus from Egypt. Some authorities consider
Eumenes to have been only an improver of the art
of preparing skins for writing on, which Herodotus
says were commonly used for that purpose in his
time; and it is even asserted that the word pergamem
was not used until several centuries after the death
of Eumenes. According to Mabillon, the first writer
who uses the term is Tatto, a monk of the fourth
century; before his time, the word memlzmvza was
employed, as in the Greek Testament, 2 Tim. iv. 13.
In a small work on Arts and Trades, published at
Frankfort in 1568, there is a cut representing the
parchment—maker at work with tools and apparatus
similar to those now in use. The skins of most ani-
mals are adapted to the manufacture of parchment,
but as the better kinds of skins are in great demand
for making leather, sheep-skins are commonly used.
The finer kind of parchment, called vellum, is made
from the skins of calves, kids, and dead-born lambs:
the stout parchment used for drum-heads is made
from the skins of asses, calves, or wolves, the last-
named being preferred; the parchment of battledores
is from asses’ skin, and for sieves the skin of the he-
goat is preferred. The skins are all prepared in a
similar manner. When the hair or wool is got ed’ by
some of the processes described under LEATHER, the
skin is put into a lime-pit, and when the fat has com-
pletely combined with the lime, the skin is stretched
upon a stout wooden frame or herse, Fig. 1589, con-
sisting of 41 bars per-
forated with holes,
each of which is oc-
cupied by a. peg. By
means of these pegs
., the skin is stretched
in the frame, for
which purpose a
Dnumber of pieces of
E ' twine are tied firmly
to the edges of the
5 skin, and to prevent
: ‘ i y the skin from slip-
Mt ‘ll ‘ .5 ping when strained
‘‘ ‘F tightly, each string
.- a is tied round a small
‘ wad or ball, formed
by making a small
fold at the side of the skin, and rolling up a shred of
skin in this fold. In some cases skewers are stuck
into the edges of the skin, and the string is tied
firmly to them. In either case, the other end of the
string is passed through a hole in the side of the peg,
and in turning this the string is wound round it, and
thus the skin is gradually and equally strained, great
care being taken to prevent the formation of wrinkles.
The herse is then set up against a Wall, and the $111‘-


.s' l I" ' if I
['l
Fig. I589.

face scraped with a double-edged knife, Fig. 1590,
(called from its shape a/zaZ/l moon knife) attached to a ~
double handle. The skin—
ner uses this knife with
both hands, and pressing
the edge againt the skin,
first on the flesh and then
on the grain side, thus gets
rid of fleshy substances,
dirt, slime, 8:0. .
In the next process, called grz'rzdz'vzy, the frame is
placed on trestles; the skin is sprinkled on the flesh
side with finely-powdered chalk or slaked lime, and
then rubbed in all directions with a flat surface of
pumice- stone. The grain side is ground with pumice
only. The knife is again passed over the skin, the
scouring with chalk and pumice repeated. This
scraping with the knife is called chaining, and serves
to whiten the skin. Fine chalk is then rubbed over
both sides of the skin with a piece of lamb-skin with
the wool on; this serves to whiten ‘the skin and to
give it a white down or nap. The skin is then re-
moved to a covered shed to dry, and in warm weather
a wet cloth is occasionally applied to it, and the pegs
tightened. When quite dry it is well rubbed with
the woolly side of a lamb-skin to get rid of the chalk.
Should any greasy matter now be detected in the skin,
it is removed from the herse and steeped in the lime-
pit for some days; otherwise it is out all round to get
rid of the wads, and transferred to a man called the
para/imam,‘ maker, who stretches it tail downwards
upon a machine, called the Sumner, consisting of a
calf-skin mounted on a frame. He then passes a
sharp circular knife over the grain surface of“ the skin
in an oblique direction, and pares off about half the
thickness of the skin, leaving a perfectly smooth
surface, an operation requiring a flexible wrist and
considerable skill. The skin is scraped on the grain
side only: should any roughness appear, it is removed
by rubbing with pumice-stone, for which purpose it
is placed upon a form or bench covered with parch-
ment and stuffed with flock. After this the parchment
is fit for writing on. If any small holes appear in the
skin they are stopped by cutting the edges thin, and
laying on small pieces of parchment with gum water.
The green colour given to the parchment used for
bookbinding is given by boiling in 500 parts distilled
water, 8 parts cream of tartar, and 30 of crystallized
verdigris; adding a parts of nitric acid when the
solution is cold. The parchment having been moistened
with a brush, the colour is spead evenly over the
surface. Polish is given by white of egg, or mucilage
of gum arabic.
PARING—KNIFE, a lever knife about 3 feet long,
one end terminating in a hook, and the other in a
transverse handle. The hook plays in an eye-bolt
attached to the bench or block, and below the cutting
edge, which is towards the hooked end, is a detached
cutting board for supporting the wood to be shaped,
and for receiving the edge of the knife. The paring-
knife is used by the turner to prepare woods for the


Fig. 1590.
878
PASTILLESUPEARL.
lathe ; also by the makers of shoe-lasts, clogs, pattens
and toys. The edge of the knife is sometimes curved
like a gouge.
Toy makers are accustomed to use .a paring¢knife
with an edge 12 or 14 inches long, and working in a
guide. The pieces of birch, alder, 860., used for parts
of toys are softened by boiling in water for about an
hour, and while hot are worked with great ease and
precision, slices being pared off in the direction of the
_.\


Fig 1591‘.

grain measuring a by 6 inches: these are wedged
tight in rows, and thus dry quite flat, so as to require
no further smoothing. Small cart wheels 1 or, 2 inches
in diameter and i to -2— inch thick are thus cut across
the grain out of cylinders previously turned and bored,
the hot wood being so flexible that it yields to the
knife without breaking transversely.
PARQUETRY. See MARQUETRY.
PARTING. See Assume—Simian.
PARTITIONS. See FLoons.
PASTES, on FICTITIOUS GEMS. See GLASS, Sec. IV.
- PASTILLES, small cones made of gum benzoin,
powder of cinnamon and other aromatics, and used
for burning as incense, or for diffusing a pleasant
odour through an apartment. The term past‘z'lle is
also applied by the French to certain aromatic sugared
confections : they are also named z‘ablezfi‘es.
PATTERNS. See CASTING AND Founnrne~also
CALIco PRINTING—WEAVING.
PAVEllIENT. See ROAD—TILES.
PA-V—I—N G. See Roan.
PEARL. A shelly secretion of a spherical shape
formed in a species of oyster, or pearl mussel, and
said to be produced by a malady in the animal, which
requires nearly seven years for its full development,
after which the oyster dies. Small pearls which have
been immersed in acetous acids, and thus reduced to
their membranous constituents, have the appearance
of being formed of concentric coats‘ of membrane, and
carbonate of lime, thus resembling in composition the
mother-of-pearl with which oyster-shells are lined.‘
The precise origin of pearls is unknown, but it appears
probable that some minute substance, such as a grain
of sand, may have found its way into the shell and
produced irritation, and that the animal, unable to
expel it, renders it less injurious by covering it with
calcareous matter. It 'is sometimes aflirmed, that to
produce pearls, the oyster must have received some
external injury; and this is corroborated by the fact
that nearly all the shells in which pearls are found
are outwardly contorted, and that a smooth regular
shell is a pretty sure sign of the absence of the pearl.
It was therefore suggested to the Swedish govern-
ment by the celebrated Linnaeus, to pierce small holes
then restore it- to its original bed. The experiment
was tried,- but without success. A somewhat similar

plan is said to be adopted by the Chinese, and with
favourable results. These ingenious people thread
upon fine silk small beads of mother—of-pearl, and
fasten them within the shells of pearl oysters, when
they rise to the surface of the water at the beginning
of summer. The animals are then restored to their
bed, where they soon cover the beads with calcareous“
matter, and thus convert them into pearls.
In whatever way produced, pearls of considerable
size, on account of their beauty and rarity, have been
valued at enormous prices in past ages, and are still
among the choicest objects of the jeweller’s art. Their
delicate and silvery lustre has been as widely cele-
brated as the brilliancy of the diamond. The Hindoos
poetically describe them as drops of dew falling into
the shells when the fish rise to the surface of the sea
in the month of May, and becoming by some unex-
plained action of the sun’s rays transformed into
pearls.
Pearl fisheries exist inCeylon, on the Coromandel
coast, and in the Persian Gulf, the last-named being
the most productive. Fisheries of less importance
also exist in Algiers, and in the Zooloo Islands. Two
thousand years ago the Romans found pearls in
Britain, and within modern times the rivers of Scot-
land have afforded considerable quantities, though
not of the best quality. Several rivers of Saxony,
Silesia, Bavaria, and Bohemia afford pearls, and they
are also found in two or three Russian provinces.
There are also pearl fisheries in the western hemi-
sphere. The coast of Columbia and the Bay of
Panama have furnished considerable quantities, but‘
they are not considered equal to the pearls of the
East in shape or colour. Detailed accounts of the
pearl fishery of Ceylon have been given by the Count
de Noé and others who have had ample means of watch-
ing the operations of the pearl- divers during a residence
in that island. It appears that the pearl oysters occur
in banks at greater or less depth in the sea on the
western side of the island of Ceylon, the average
depth, however, being about 12 fathoms, and the dis-
tance from the shore about 15 miles. The right to
fish on these banks is sold by the government every
season, and a single auction sale is generally made to
one individual, who afterwards disposes of shares in
the fishery to other‘ parties. The biddings at the
auction are regulated by the produce of some thou‘-
sands of oysters taken from the beds at hazard. If
the average quality of pearls contained in them be
good, the competition is strong in proportion.
The pearl fishery commences in April and lasts till
towards the end of May. It attracts a concourse of
visitors not only‘ from the interior of the island, but
from various parts of India, whose diversities of
language, dress, and manners produce a striking
effect. The sea-shore, at other times solitary, is on
the eve of the fishery suddenly covered with innu-
lmerable huts, composed of a few poles stuck in the
ground, interwoven with bamboo and covered‘ with
in the shell of the freshly-caught pearl oyster, and '
the leaves of the cocoa-nut palm: these temporary‘
* dwellings often. shelter as many as 150,000 persons;
{The signal for commencing the fishery is ‘given at
.PE ARL.
379
day-break by the firing of cannon; and at that moment
the several boats cast anchor in the fishing ground,
for at midnight they had left the shore in an extensive
fleet, so as to be on the spot at the desired moment.
Each boat has its own proper bounds, beyond which
it is not lawful to work, and ‘government vessels are
on the spot to see that no infringement of contract
takes place. The boats each carry a captain, a pilot,
and 20 men, of whom 10 are experienced divers.
5 divers descend at once, the other 5 taking the
plunge when the first ascend. Thus a little time is
allowed for regaining strength. In order‘ to descend
as rapidly as possible through the water, the diver
places his feet on a large stone made fast to one end
of a rope, the other end being secured to the boat.
He also takes another rope, to the end of which is
attached a net, or basket, to contain the oysters.
The upper extremity of this second rope is held by
two men in the boat. The diver is also provided with
a strong knife for detaching the oysters, and as a
means of defence against sharks, which are very
numerous in those seas, but which do not often at-
tack the divers, being perhaps scared by the noise of
the assemblage, and the continual plunging of so
great a number of persons. The diver no sooner
reaches the ground than he gathers oysters with all
possible speed into his basket, and then letting go
the rope to which the stone is attached, he pulls that
which is held by the sailors, and rapidly ascends to
the surface. Some divers make very dexterous use
of their feet, holding the net with one foot, clasping
the stone with the other, and thus leaving one hand,
free to close the nostrils, while the other hand holds
the rope in descending.
The time during which the divers can remain sub—
merged is variously stated, and no doubt it differs
greatly according to the constitution of the individual.
Some observers declare that in their experience it
never exceeded 50 seconds; but Captain Percival, in
his work on Ceylon, gives 2 minutes as the usual
time of remaining under water.1 Serious effects are
produced by this employment, and the divers may fre-
quently be seen with blood issuing from their mouth
and nostrils. Yet this does not hinder them from
going down in their turn. They will make from
40 to 50 plunges in one day, and bring up on each
occasion about 100 oysters. Their day closes before
noon, for as soon as the sea~breeze sets in, the
signal is given for the return of the boats to the
shore. Their owners, and a large assemblage of
persons of all classes, are eagerly looking out for the
arrival of the flotilla, and are soon busily employed
in examining and stowing away the cargoes.
Each owner has a shallow pit fenced round and
secured for his own use, in which his store of oysters
is deposited, and left open to the air. This pit, or
0024120’, as it is called, is in the midst of a group of
huts belonging to the same owner, so that it is under

(1) Dr. Faraday found that by first exhausting the lungs, by
several deep exhalations, so as to expel the carbonic acid, and
then taking a deep inspiration of fresh air, ‘he was able to hold his
breath for two minutes and a half.
‘in with a little wooden hammer.

guard of- his party. Here the oysters are allowed to
putrefy under a burning sun, and a stench arises from
them which would seem enough to depopulate the
shore of its thousands of inhabitants. Yet such is
not the case. The health of the people does not
appear to be materially affected, and the oysters are
allowed to remain till dry, when they can be easily
opened and the pearls extracted. To open them when
fresh would require much greater force, and would be
likely to injure the pearls. When the putrefaction is
sufficiently advanced, the oysters are taken from the
coutéd'and placed in troughs made of the trunks of
trees. Sea—water is thrown over them: they are
easily opened, and render their pearls to the washing
and shaking of a number of men who stand all on
one side of the trough, while inspectors at each end
closely watch their proceedings, and other inspectors.
examine the shells which are thrown away, lest they
should contain some of the precious substance. The
workmen engaged in washing pearls dare not lift
their hands to their months under penalty of a
flogging, yet a man will sometimes contrive to swallow
a pearl of high price. After all the pearls are washed
out, the largest are carefully picked out from the
sand at the bottom of the troughs and washed re~
peatedly in clean water; the next in size are spread
out on white napkins to dry in the sun. The re-
mainder are left to the care of women, who pick them
up and dry them. Pearls are asserted by means of
three sieves placed one above another, the meshes in
which are smaller as the pearls descend. Thus the
pearls which will not pass through the uppermost
sieve are of the first class, and so on with the others.
Another assortment is made as to colour, regularity.
of form, 850., and here the tastes of different nations
have to be consulted. The Europeans prefer pure
white pearls, the Indians yellow pearls, and the
natives of Ceylon those which are tinged with rose-
colour.
Besides the number of persons who arrive in Ceylon
in the fishing season for the sake of speculating in
pearls, there are also numerous Indian artisans who
are very expert in piercing and drilling pearls, and
who practise their trade on the spot on economical.
terms. Captain Percival thus describes their opera-
tions:——“A machine made of wood, and of a shape
resembling an obtuse inverted cone, about 6 inches
in length and 4! in breadth, is supported upon 3
feet, each 12 inches long. ,In the upper flat sur—
face of this machine holes or pits are formed to
receive the larger pearls, the smaller ones being beat
The drilling instru—
ments are spindles of various sizes, according to that
of the pearls; they are turned round in a wooden
head by means of a bow handle, to which they are
attached. The pearls being placed in the pits which
we have already mentioned, and the point of the
spindle adjusted to "them, the workman presses on the
wooden head of the machine with his left hand, while
his right is employed intin'ning round the bow handle.
During the process of drilling he occasionally moistens
the pearl by dipping the little finger of his right hand
380
PEARLS, ARTIFIoLiL-imcTINE-rnnonn'rnn.
in a cocoa-nut filled with water, which is placed by
him for that purpose; this he does with a dexterity
and quickness which scarcely impede the operation,
and can only be acquired by much practice. They
have also a variety of other instruments both ,for
cutting and drilling the pearls. To clean, round, and
polish them to that state in which we see them, a
powder, made of the pearls themselves, is employed.
These different operations in preparing the pearls
occupy a great number of the black men in various
parts of the island. In the black town or pettah of
Columbo, in particular, many of them may every day
be seen at this work, which is well worth the atten_
tion of any European who is not already acquainted
with i .”
PEARL, MOTHER OF.
PEARL.
PEARLS, ARTIFICIAL. The art of making
artificial pearls has been brought to such perfection in
Paris, that ‘even jewellers and pawnbrokers have occa-
sionally had a difficulty in deciding between the arti-
ficial and the real. The origin of this successful
imitation is given as follows z—A French bead maker
named Jaquin, observing that when the small fish called
abletzfe,’ or bleak (Q/prz'rzus albm'mes), was Washed,
the water was filled with fine silver-coloured particles,
collected some of these for the purposes of his trade.
He found that the soft shining powder thus obtained
had to aremarkable degree the lustre of pearls ; hence,
he called it essence of pearl, or essence zl’orz'eizt. He
first made small beads of gypsum and covered them
with this substance: they were greatly admired and
eagerly sought after; but it was found that this
pearly coat, when exposed to heat, separated itself
from the bead, and attached itself to the skin of the
wearer, in a manner that was anything but pleasant.
The ladies themselves, it is said, suggested to Jaquin
the making of hollow glass beads, and covering the
inside with essence of pearl. This he did, and
established a manufacture, of which some idea may
be gained by the following account. Slender tubes
of glass are first prepared, called gimsols, a term
applied to opal, and sometimes to the stone called
cat’s-eye, and given to these tubes because the glass
is of a peculiar bluish tint. From these the artist
blows minute globules, to the extent of from two to
six thousand per day, not caring to make them all
perfectly regular, or free from blemish, because the
natural pearls are not so. The pearl essence is then
mixed with a solution of isinglass, and is blown while
hot into each head by means of a fine glass pipe. The
solution is spread equally over the whole internal
surface, by shaking the pearls in a vessel placed over
the tablelwhere the workman sits, and to which he
gives motion by his foot. When the varnish is
equally diffused and dry, the beads are filled with
white wax; this gives them the necessary weight and
solidity, and renders them less fragile. They are
then bored with a needle, and threaded on strings for
sale. The holes in the finer sort are lined with thin
paper, that the thread may not-adhere to the wax.
To produce one pound of scales no fewer than
' See Morrrnn- or -

4,000 fishes are required; but this quantity of scales
only yields 4! ounces of pearl essence. The fish
are about 41 inches long; they are sold at a cheap
rate in the markets after being deprived of their
scales. The value of a pound of washed scales in
the Chalonnais is from 15. to 25 livres. The
early manufacturers suffered great inconvenience
from not knowing how to preserve the scales from
putrefaction, and consequently being obliged to use
the essence immediately it was obtained, lest it
should acquire the intolerable odour of decayed fish.
Attempts were made to preserve them in spirit of
wine or brandy, but those liquors wholly destroyed
their lustre. At length it was discovered that these
fishy particles can‘ be kept for a long time in solution
of ammonia, and this enables the manufacturers of
artificial pearls to carry on a considerable traffic with
distant places where the fish is plentiful, the supply
from the Seine, though abundant, being insufficient
for the purposes of the trade of Paris. Down to a
late period the heirs of M. Jaquin continued to
manufacture 'pearls to a considerable extent, in the
Rue de Petit Lion, at Paris. An elaborate account
of this art is given by De Beost in a work entitled,
“ L’Art d’z'mz'z‘er Zea Perles fines,” from which most
English descriptions of this manufacture have been
obtained.
PEARL ASH. See POTASSIUM.
PEARL WHITE. See Brsirn'rn.
PEAT. See FUEL, also Inrnonnoronr Essxr,
p. lxxxiv. _
PECTINE ('n-qx'r‘ts, eoaguhmz), the jelly of fruits,
and distinguished from animal jelly in containing no
nitrogen. The firm consistence of currant and other
fruit jellies is due to this substance. It can be
obtained from various fruits, by expressing their
juice, and evaporating it at a temperature not exceed-
ing 212°. “ It may be obtained by the addition of
alcohol ‘to the recently-expressed juice of ripe cur-
rants or gooseberries: in the course of a few hours a
gelatinous substance separates, which must be washed
with weak alcohol and dried; it then resembles
isinglass in appearance, and when digested in cold
water, swells into a soft pulp, somewhat like starch :
it is not blued by iodine. It may also be procured
from the rasped roots of carrots and turnips.”
(Brenda) In contact with bases pectine becomes
converted into perz‘z'e acid, but its acid properties are
feeble, and its salts incapable of crystallizing. Pec-
tine is said to contain GieHizOie, and pectic acid
0161111015. Pectic acid has been recommended in
France as part of the diet of invalids: it is also said
to be an antidote in cases of poisoning by certain
metallic salts, by forming insoluble compounds with
their oxides. Pectic acid imparts a gelatinous cha-
racter to soups prepared from roots which yield it.
PEDAL. See ORGAN.
PEDOMETER (work, a foot, and pre'rpov, a mea-
sure) ; also called pemmbulazfor, way-wiser, odometer,
or road-measurer; an instrument formed like a watch
with a train of wheels arranged on the same plane:
by means of a chain or string fastened to aman’s;
PED OMETER.
381
foot, or to the wheel of a carriage, the train advances
a notch at each step, or at each turn of the carriage-
whcel, and in this way the distance traversed is
measured, and represented by a hand moving round
a dial.
A form of perambulator often used on our public
roads is represented in Fig. 1592. It consists of a
Fig. 1592.


wheel 2 feet 7 5; inches in diameter, so arranged that
the circumference (8 feet 3 inches) shall be exactly
equal to half a pole. On the end of the axis of the
wheel is a nut 13— inch in diameter, divided into 8 teeth,
which, on moving the wheel round, fall into the 8
teeth of another nut 64 attached to one end of an
iron rod, which is thus turned once round in one
revolution of the wheel. This rod occupies a groove
in the side of the frame, and at the other extremity
of the rod is a square hole which receives the end (1
of a small cylinder 0 [Z placed under the dial-plate of
a piece of mechanism at the end of the frame at 6,
so as to move about its axis. The end a is formed
into a perpetual screw, which works into 32 teeth of
a wheel arranged at right angles to it, so that when
the instrument is driven forward, this index-wheel
makes 1 revolution to 16 poles of distance traversed.
On the axis of this wheel is a pinion with 6 teeth,
which, working in another wheel of 60 teeth, carries
the latter round once in a distance of 160 poles, or
half a mile. This last wheel carries round with it
a hand or index over the surface of a dial-plate, the
outer rim of which is divided into 160 parts corre-
sponding to the 160 poles. Also on the axis of the
last-mentioned wheel is a pinion of 20 teeth, which,
working into another wheel of 40 teeth, drives it
round once in a mile. On the axis of this mileewheel
is a pinion of 6 teeth, which, working into a wheel of
72 teeth, causes the latter to rotate once in 12 miles.
This last wheel carries an index-hand, which moves
over the surface of the dial-plate, but its indications
are measured by an inner graduated circle divided
into 12 equal parts for miles, and each of these is
subdivided for halves, quarters, and furlongs.
By varying the number of teeth in the pinions any
standard of land-measure may be taken. If con-
structed with tolerable care this instrument affords
pretty correct indications. Major Rennel states, that
during the survey of India, be measured a meridian
line of 3 degrees with this instrument, and found it
to agree very closely with the measurement given by
astronomical means.
The term pedometer is usually applied to instrue

ments smaller than the above, such as can be worn on
the person of a pedestrian for measuring the distance
traversed on foot. Payne’s pedometer is small enough
to be worn in the waistcoat pocket, and is set going
by the rising and falling of the body at each step in
walking. The working parts of this instrument are
shown in Figs. 1593, 1594, in a front and back view.


Fig. 1593. Fig. 1594.
L is a lever, adjusted so as to vibrate upwards and
downwards at every step of the pedestrian. At one
end of this lever is a weight w, and at the other a; pivot
x. Below the lever is a spring s, which keeps the
lever when at rest close up to a regulating screw is ;
the screw and the spring being so adjusted as to be
only just sufficient to overcome the weight of the
lever, and to prevent it from falling downwards. The
lever must be kept horizontal, for which purpose the
instrument is hung in the waistcoat pocket by the
hook H, and‘ thus, every time the foot is placed on
the ground preparatory to taking a new step, a slight
jerk is produced, which causes the lever to sink a
little, and the spring immediately returns it to its
place. Thus it will be seen that the lever oscillates
at every step, and these oscillations are made to act
on an index hand by the following contrivance :—
Fitted to the axis x of the lever, and moving with it,
is a small ratchet-wheel A; beneath this is another
and larger ratchet-wheel B fitting loose on the axis.
These 2 wheels are connected together by a ratchet
in such a manner, that when the lever falls both
wheels are moved forward one or more teeth; but
when the lever rises again by the force of the spring
s, the larger ratchet-wheel B is held fast by the ratchet
r. This wheel is is connected with the series of
toothed wheels and pinions o n n, Fig. 15 93, by means
of a pinion 1:‘ fixed in its under surface. The centre
wheel n carries an index hand, which points to the
figures on the dial-plate which indicate the number
of miles passed over. This little instrument is usually
made to register 10 miles, but by regulating the pro-
portions of the wheels and pinions, it can be adjusted
to any standard. By using an extra pinion and wheel,
after the manner of the seconds-hand of a watch, and
making the wheel with 10 times the number of teeth
contained in the pinion, the instrument will be capable
of registering 100 miles instead of 10. The mechan-
ism of the pedometer may be combined with that of
a watch, so that the pedestrian may compare the dis-
tance traversed with the time occupied.
382
PENS.
in the museum of King’s College, London, is a
way-wiser, constructed by the Hon. Henry Cavendish.
So lately as December 1851, a patent for an odometer
was granted to Mr. W. Grayson. This apparatus con—
sists of a train or system of wheelwork, enclosed in
a box attached to one side of the carriage above the
axle of the wheels. It is provided with two dials;
one outside, for the use of the passenger or driver;
the other inside, for the protection of the proprietor,
and accessible only to him. The index hands of the
two dials are connected by intermediate gearing, so
as to act in unison; but the passenger index-hand is
attached to a hollow shaft, fitting over its driving—
spindle, and actuated by contact, to admit of the
hand being set to zero, on the entrance of a passenger
into the carriage, without deranging the apparatus.
The apparatus is set in motion when the wheels of
the carriage are revolving, by the intervention of a
pendent lever, one end of which is acted on by a pin
attached to the nave of one of the wheels, while the
other end engages in a ratchet-wheel, forming part of
the train of wheelwork, which it moves forward one
tooth for every revolution of the wheels. The num-
ber of teeth on the ratchet-wheel will be determined
by the size of the driving-wheels of the carriages,
and apparatus may be adapted for use with driving-
wheels of different diameters, by simply changing the
ratchet-wheel.
PELTRY. See FUR.
PENS. The earliest pens, such as were used for
writing on papyrus with a fluid ink, appear to have
been made of reeds. In our translation of the Old
and New Testaments, the word pen refers either to
an iron style used with waxed tablets, or to a reed,
quills not having been introduced earlier than the
fifth century. It is uncertain what particular kind
of reed was used for making pens, but it is described as
a small, hard, round cane, about the size of a large
swan’s quill. The supply of these reeds was obtained
from Egypt, Cairo in Asia Minor, and Armenia.
Chardin and Tournefort describe a kind of reed used
for pens in Persia. These reeds are collected near
the shores of the Persian Gulf, whence they are sent
to various parts of the East. After being out, they
are deposited for some months under a dunghill, when
they assume a mixed black and yellow colour, acquire
a fine polish and a considerable degree of hardness,
and the internal pith dries up into a membrane which
is easily detached. Reed pens are still in use, and
they suit the Arabic character better than quill pens.
The Arab, in writing, places the paper upon his knee,
or upon the palm of his left hand, or upon a dozen or
more pieces of paper attached together at the a
corners, and resembling a thin book, which he rests
on his knee. The ink is very thick and gummy.
The quills used for pens are chiefly from the goose,
the swan, and the crow; but the ostrich, turkey, and
other birds occasionally contribute. The general use
of steel pens has greatly lessened the demand for
quills; but it appears, that in the year 184.10, when
the import duty on goose-quills was 28. 6cl. per 1,000,
as many as 22,024,000 quills had been entered for

home consumption in that year. In 1842 the duty
was reduced to Gal. per 1,000. Most of the goose-
quills are from the Netherlands and Germany, Russia
and Poland. In the two latter countries vast flocks
of geese were maintained for the sake of their quills.
When the demand was large, this country has re-
ceived from St. Petersburgh alone as many as
27,000,000 quills in one year. Some idea of the
number of geese required to keep up such a supply
may be judged of from the fact, that each wing pro—
duces about 5 good quills, and that by proper manage-
ment a goose may afford 20 quills during the year.
Quills are classified according to the order in which
they are fixed in the wing, the second and third quills
being the best. The goodness of quills is estimated
partly by the size of the barrel, but more by the
weight; hence the denomination of quills of 14:, 15,
&c. loths per mills, the mille consisting of 1,200
quills.
The quills as they come from the bird are covered
with a membrane, and are tough and soft, so that
they will not make a clean slit: they are also opaque,
and the vascular membrane adheres strongly to the
interior surface of the barrel. These defects are got
rid of, and the quills prepared for the pen-maker, by
the operations of quill—dressing or gulll-alulc/zz'zzg. The
quills are first sorted, according to the length and
thickness of the barrel, into primes, seconds, and piniorzs.
They are then alert/Zeal by the removal of the mem-
branous skin, for which purpose they are plunged
for a short time into hot sand, the heat causing the
outer skin to crack and peel off, its removal being
facilitated by scraping with a sharp instrument: at
the same time the internal membrane becomes shri—
velled up and falls down towards the point of the
quill. The effect of the heat is also to consume or
dry up the oily matter of the quill, and thus to render
the barrel transparent. This process, which may be
repeated several times, is called clutching, probably
from the circumstance of its having been first adopted
in Holland. The heat requires regulation, or the
barrel will be injured; but the effect of the process is
to give to the barrels the colour of fine thin horn, or
an impure white. In some cases a uniform yellow
colour is produced by dippingflthe barrels in dilute
nitric acid. This process hardens them. Quills may
also be hardened by steeping for a few minutes in
alum-water at a boiling temperature. The quills
having been dressed and finished, a portion of the
barb is stripped off so as to occupy less room in pack-
ing, and the quills are tied up in bundles of 25 or 50
each for the market.
A different mode of preparing the quills is adopted
by some dressers. The quills are first moistened,
not by immersion, but by dipping their extremities
into water, and allowing the moisture to be absorbed
by capillary attraction. They are then heated in the
fire or over a charcoal chauffer, and next passed
quickly,under an instrument with a fine edge, which
flattens them, and apparently spoils them: they are
again scraped and exposed to heat, whereby they
assume their original form. It is a remarkable fact,
PENS.
383
that, after crushing a feather in this way, it may be
restored by exposure to steam or a moderate heat.
The quills, having been prepared, are cut into pens
by the pen-cutter’s knife, and are also trimmed. A
pen-cutterwill cut in a day two-thirds of a long thou-
sand (1,200). ' Some years ago, a house in Shoe-lane
out about 6,000,000 pens yearly.
Crow-quills are usually employed in fine drawings,
on account of the fine point to which they can be
brought. They are useful in that laborious kind of
etching intended to imitate prints.
Before steel pens became common, a number of
pens were cut out of the barrel of a quill just as they
are now out out of sheet steel. The narrow end, and
also the stalk of the quill, having been cut off, a
cylinder was passed through the barrel and 2 cutting-
edges passed along it, 1 on each side, whereby the quill
was separated into 2 semi-cylinders. These pieces were
then placed in a groove with the convex side under-
most, and the edges smoothed with a plane. Each
half cylinder was then cut into 3 or éh pieces, and each
piece operated on by a small cutting-press or nibbz'ng-
mac/zine. A few strokes with a pen-knife then gave
the form of a pen to each piece, and being fixed in a
handle, was fit for use.
From the softening of the quill pen by the ink, and
the wear of the points by friction, frequent mending
was required, or very bad writing was the result. The
first attempts to render pens more permanent con-
sisted in arming the nibs with metallic points. Pens
were also constructed of horn, tortoise and other
shells, and also of glass. Nibs have also been formed
of precious stones. In 1823 Messrs. Hawkins and
Mordan employed horn and tortoise-shell cut into
nibs, softened in boiling water, and small pieces of
diamond, ruby, 8:0. imbedded into them by pressure.
Thin pieces of gold or other metal have also been
attached to tortoise-shell. In Mr. Doughty’s pens
the nibs were rubies set in fine gold: these pens were
very durable, and the writing always uniform in cha-
racter. To prevent the points being injured. by con-
tact with hard substances, the inkstand is to be lined
with Indian-rubber. Dr. Wollaston also constructed
pens with-two fiat slips of gold placed angularly side
by side, and tipped with rhodium. In the Great
Exhibition, Messrs. Wiley of Birmingham exhibited
specimens of gold, palladium, gold and silver, and
silver pens, pointed with the native alloys of iridium
and osmium. Such pens not being acted on by the
ink, are almost indestructible by ordinary usage.
The permanent pens above alluded to were costly,
or deficient in elasticity, or easily liable to injury.
Additional elasticity was obtained by springs on the
backs of the pens, made to slide backwards and for-
wards, so as to vary the elasticity: but it was found
that the drying of the ink in the pen greatly inter-
fered with the action of the spring.
The first notice that we find of steel pens for
writing is in 18 03, when Mr. Wise constructed barrel-
pens of that metal mounted in a bone case for carry-
ing in the pocket. These pens were costly, and not
very successful. This form of pen, as improved by

Mr. Gillott of Birmingham, was for many years in
request. In the improved pen, metal of better quality,
thinner and more elastic, was employed: the‘ slit was
made shorter, and the finish and temper of the metal
more carefully attended to. At the same time such
was the reduction in price that a gross of pens was
sold for, little more than what was charged for one of
Wise’s pens; We are not aware whether Mr. Gillott
or Mr. Perry was the first to introduce the improve-
ments which led to the present form and make of
steel pens. Both gentlemen, the latter especially,
have taken out a number of patents for their pens,
and have advertised them extensively for many years.
In 1831 Messrs. Mordan and Brockedon brought out
an oblique pen, in which the slit was inclined at an
angle of 35° to the general direction of the pen, the
oblique position in which an ordinary pen is usually
held suggesting the change. Then there Were lunar
pens, in which the under surface was large and con
cave, so as to hold a good deal of ink. Mr. Gowland
invented a pen with an additional nib, called the
three-nabbed slit pen. A large number of other forms
have also been introduced, and have had their brief
periods of existence. The ordinary form of steel pen,
resembling that of the common quill pen, has long
and deservedly maintained its ground, and still con-
tinues to be manufactured in vast numbers.
Birmingham is the chief seat of this manufacture.
The steel for making pens is rolled for the purpose at
Sheffield into thin sheets, and these are cut into slips
about 4! inches broad and 3 feet long, then annealed,
the scales removed by pickling in dilute sulphuric
acid, after which the strips are again rolled to the
required thickness. From these strips blanks or flats
are out out by girls, by means of a bed and punch,
much in thelsame way as blanks for buttons, [see
BUTTON ;] care being taken that the fibres of the steel
run in the direction of the length of the pen. The
next operation is to pierce the hole which terminates
the slit, and remove any superfluous steel which is
likely to interfere with the elasticity of the pen. The
blanks are then annealed in large quantities in a
muffle, after which the maker’s name, 850., is stamped
upon each blank by means of a small punch. The
blanks are still fiat pieces of steel. They are now
transferred to another class of workers, who by means
of a press make each piece concave for nib-pens, and
form the barrel for barrel-pens. The pens are enclosed
in an iron box, and heated in a muffle, and when of a
uniform red heat, they are hardened by being plunged
into oil. The adhering oil is removed by agitation in
a tin-plate barrel. They are next tempered, and lastly
placed in a revolving cylinder with sand, pounded
crucible, or other cutting material, which brightens
them to the natural colour of the steel. The nib is
next ground with great rapidity by a girl, who picks
up each pen, places it in a pair of plyers of the proper
form, and finishes it with a single touch on a small
emery wheel. After this the slit is made by means
of a chisel or wedge with a flat side fixed to the bed
of a press, the descending screw of which has also
a chisel or cutter, which very accurately corresponds
384:
PEPPER—PEPPERMINT—PERCUSSION CAPS.
with the former. After the slits are made, the pens
are coloured brown or blue by placing them in a re-
volving metal cylinder over a charcoal stove, and
removing them the moment the film of oxide of the
desired colour is formed. The pens are lastly im-
mersed in a solution of lac in naphtha, which imparts
brilliancy after they are dried by heat. The pens are
then counted and made up in boxes.
There was a large display of steel and other pens
in the Great Exhibition, among which those by Mr.
Gillott were conspicuous. It is stated in the Illus-
trated Catalogue that this exhibitor employs upwards
of 500 persons, of which four-fifths are women,
skilled workmen being employed to repair and set
the tools. ' Mr. Gillott’s annual production ofpensis
said to exceed 150 millions. Messrs. Hincks, Wells
and Co. of Birmingham exhibited specimens .of
Lillipnzn'nn pens, intended to 'show the skill of the
tool cutter, and the perfection of the machinery
employed. Agro'ss of the smallest weighed less than
as grains, and could be contained in a Barcelona nut-
shell.
PENGIL. See BLACK-LEAD.
PENDULUM. See HonoLocY.
PEPPER, the dried fruit of a climbing plant
(Piper nigmm) extensively cultivated throughout a
wide range of countries in the East, including Sumatra,
Borneo, the Malay Peninsula, and all countries to the
east of the Gulf of Siam. The berries grow in long
thin clusters, ‘and are gathered while yet green or
when only a few are beginning to turn red. They are
quickly dried on mats in the sun, and become the
shrivelled black pepper as we receive it in this
country. White pepper is the same fruit freed from
the outer rind by macerating in water.
The pepper gardens of the East are marked out
in a square or oblong form, and planted in even rows,
running parallel and at right angles with each other.
The intersections forming the intervals between the
plants are at the distance of 6 feet from each other.
The usual mode of propagating the pepper, is by
cuttings, a foot or two long, taken from the horizontal
shoots that run along the ground from the old vines.
With the cuttings of the pepper plant are also in-
serted cuttings of a rapidly growing tree, which is to
serve as its support. Several kinds of tree are
employed for this purpose. The number of plants in.
a Sumatran pepper ground is from five hundred to a
thousand, but occasionally gardens of two or three
thousand vines are heard of. The pepper does not
show blossom till the third year, and in the rainy
season which succeeds the first appearance Of the
fruit the whole plant is loosened from its support,
and turned down again into the earth with only
a small shoot left aboveground. This, however,
grows more vigorously than ever, re-ascending the
prop in one season to the height of 8 or 10 feet, and
bearing a full crop. This increases every year to the
seventh or eighth, when the vine is at its best condition,
and continues in that state for about 41 years, when
it gradually declines. On the first appearance of the
decline of one pepper garden, another is immediately

planted, to allow time for the second to come into
hearing before the first has ceased to yield a remune-
rative supply. Pepper grounds are usually on the
level banks of streams, and the produce is conveyed
on rafts to its destination.
The analysis of black pepper gives soft resin, a
volatile oil, piperine, extractive gum, bassorine, malic
and tartaric acids, salts, 820., the odour being ap-
parently due to the volatile oil, which is not acrid,
and the pungent taste to the resin. Piperine is an
inodorous and tasteless substance, discovered by
Oersted, in black pepper. It is extracted by digest-
ing 16 oz. of coarsely-powdered pepper for 48 hours
in twice its weight of water, 5 times in succession;
then pressing out and drying the insoluble portion,
and digesting it for 3 days in 24; ounces of alcohol.
This solution is then pressed out, filtered and evapo~
rated to the consistence of syrup; crystals are
deposited, which are freed from adhering resin by
ether redissolved in alcohol, purified by animal
charcoal, and recrystallized.
PEPPERMINT (men/inn pipem't‘n), a plant common
in many parts of Britain, but cultivated for the sake
of its volatile oil. The. plant when dried is more
powerful than in the fresh state; it is of a lively green,
with a peculiar aromatic odour, and a pleasant taste,
resembling camphor, burning at first, but afterwards
leaving an enduring sensation ‘of cold in the mouth.
The dried’ herb is used for preparing a distilled water
as well as the volatile oil. The oil is obtained by
distilling the herb with water. It is of a pale yellow
or greenish yellow tint, which in some cases deepens
by age. It has a strong odour of the plant, and a
hot aromatic taste succeeded by coldness on the
tongue. Three varieties of the oil occur in commerce,
the German, English, and American. - 20 lbs. of the
herb yield from 4: to 6 drachms of oil, but if the flowers
be also distilled, (which is done in obtaining the
American oil,) 4! ounces may be obtained. The
American oil is more soluble in alcohol than the
German: its sp. gr. is 092, but when rectified 090.
The last portions which pass over during the rectifi-
cation, deposit on being cooled a concrete substance,
stenropiene, also called peppermint camp/101' ,- it forms
colourless prismatic crystals, having the odour and
taste of peppermint ; it is almdst insoluble iii-water,
but very soluble in alcohol and ether: it fuses at
about 929, and boils at 4115"; the density of its vapour
is 5'45, and its formula C20H2002.
Oil of peppermint is stimulant and antispasmodic.
It is often adulterated with oil of turpentine, _oil-of-
marjoram, and alcohol.
PERAMBULATOR. See Pnnorrn'rnn.
PERCUSSION CAPS. Considerable doubt exists -
as to who was the inventor of percussion caps in
their present simple and effective form. It appears
that in the year 1807 the Rev. Mr. Forsyth obtained
a patent for the 'use' of fulminating powder in firing
artillery. The powder employed by him consisted
of chlorate of potash, sulphur, and charcoal,1 and

(1) The following ingredients and proportions have been recom~ _
mended :--Chlorate of potash, 6 parts; sulphur,- 3; powdered
PEWTER.
385
the apparatus for using it consisted of a magazine
turning on a roller or tube screwed into the breeching
of the gun. A small portion of fulminating powder
being deposited in the roller, the magazine was
restored to its firing position, and the cock struck
on a pin with a spiral spring attached to it, which
inflamed the gunpowder. This contrivance passed
through a great variety of forms before the per-
cussion cap was invented. According to Mr. Wil-
kinson, this invention was purchased by Mr. Egg
from Mr. Roantree, a gun-maker at Barnard Castle,
Durham, who had it from a workman employed by
Mr. Joseph Shaw, an English landscape painter,
afterwards resident in America. Mr. Shaw assured
Mr. Wilkinson that in 1814! he invented a steel cap,
which, when fired, was retained to be primed again;
in 1815 he invented a pewter cap, which was thrown
away after using; and in 1816, the copper cap similar
to that now in use.
Percussion caps are produced by pressure: the
blanks are punched out of thin rolled copper in the
form of a cross, with short equal arms, or with only
3 arms, and the blanks having been annealed, are
formed into caps by means of dies which fold up the
arms and unite them into a short tube, while the
central part of the metal which forms the top of
the cap, sustains the blow of the hammer. The
bottom of the cap is touched with a solution of gum
or glue into which the fulminating powder is dropped.
Caps are sometimes varnished to prevent them from
losing their power by exposure to damp. An exhibitor
of percussion caps in the Great Exhibition calculated,
we know not upon what data, that the total manufac-
ture of percussion caps for sporting guns in Europe,
may be estimated at 1,300 millions yearly, requiring
396,000 lbs. weight of copper. Caps for the use of
the army are formed at Woolwich by very ingenious
machinery. .
PERCUSSION, CENTRE OF. See CENTRE.
PERUVIAN BARK. See BAnx-QUININn
PETROLEUM. See ASPHALTUM.
PEWTER. Common pewter is an alloy of about
80 parts of tin and 20 of lead; but other metals, such
as copper, antimony, and zinc, are sometimes added.
The manufacturers of. pewter consider that a better
alloy is obtained by melting up old pewter with new
ingredients, so that the composition of pewter cannot
even be said to be known to the makers. The Pew-
terers’ Company1 in 1772 attempted to regulate the
quality of pewter wares by establishing “a table of
the'assays of metal and of the weights and dimensions
of the several sorts of pewter wares.” Persons who
departed from the regulations were liable to expulsion

glass, 1 part; powdered charcoal, a a part. Or, chlorate potash,
5 parts; sulphur, 2 parts; charcoal, f; a part; with from :1; to 2,;
the weight of fulminating mercury. It must be remembered
that chlorate of potash is dangerously explosive when rubbed
with sulphur. The fulminating mercury composition for caps is
fulminating mercury, 3 parts; chlorate potash, 5; sulphur, 1 part;
powdered glass, 1 part.
(1) The Pewterers of England have formed an incorporated
society ever since the reign of Edward IV. (14:74.) By act of
parliament 25 Henry VIII. their wardens had the inspection of
pewter throughout England.
VOL. II.

from the guild, but they have been so generally dis-
regarded as to have had very little effect in keeping
up a standard of pewter. The assay was directed to
be made by casting a small button of the metal, to be
tried in a brass mould so proportioned that such a
.button of pure tin would weigh exactly 182 grains.
All the metals added to the tin being heavier than -
tin, the buttons are heavier the less tin they contain.
The following scale is founded on these data :—
. 182 grains. '
_ _ metal 1% grains} 183%
heavier than tin, or
Ditto of "trifling metal 35 grains heavier} 185%
than tin,
Ditto of ley metal 16% grains heavier than} 198;
tin, ‘3
Assay of pure tin Ditto of fine or plate
count
Equal parts tin and lead are about 50 grains heavier
than tin, or 232 grains. “ Some pewters are now
made nearly as common as the last proportion: when '
cast they are black, shining, and soft; when turned,
dull and bluish. Other pewters only contain 1‘, or 1%
of lead: these, when cast, are white, without gloss,
and hard; such are pronounced very good metal, and
are but little darker than tin. The French legislature
sanctions the employment of 18 per cent. of lead
with 82 of tin as quite harmless in vessels for wine
and vinegar.2 The finest pewter frequently called
tin and temper, consists mostly of tin, with a very
little copper, which makes it hard and somewhat
sonorous, but the pewter becomes brown coloured
when the copper is in excess. The copper is melted,
and twice its weight of tin is added to it, and from
about % to '7 lbs. of this alloy, or the temper, are
added to every block of tin weighing from 360 to
390 lbs.3 Antimony is. said to harden tin, and to
preserve a more silvery colour, but is little used in
pewter. Zinc is employed to cleanse the metal
rather than as an ingredient. Some stir the fluid
pewter with a thin strip, half zinc and half tin;
others allow a small lump of zinc to float on the sur-
face of the fluid metal, while they are casting, to
lessen the oxidation.”-—Holtzap_fi"el.
Of the three ordinary sorts of pewter above dis—
tinguished, plate pewter is the hardest, and is used for
making plates and dishes. The pewter named trifle,
is used for beer pots; and ley for the larger wine
measures. Plate pewter has a bright silvery lustre
when polished; and according to Dr. Ure, the best is
composed of 100 parts tin, 8 antimony, 2 bismuth,
and 2 of copper. Trifle, 83 of tin, and 17 of anti-
mony, but it usually contains a good deal of lead.
Pewter wares are formed either by hammering or
by casting; plates and dishes being hammered, and
measures and spoons cast. In soldering together

(2) A table of specific gravities was published for the purpose of
testing the quality of the alloy, the density of which, at the legal
standard, is 7 '764. An excess of lead is at once detected by an
increased density.
(3) As the copper is much more difficult of fusion than the tin,
it is necessary, in order to cause the two metals to combine pro-
perly, to melt the a or 1 per cent. of copper, in a crucible, and to
add it to two or three times its weight of melted tin: this forms
the alloy called temper. It may be fused in a ladle, and added in
small quantities to the tin, or to the fluid pewter, until the proper.
proportions are attained.
CC
386
PHARMACY—P1210 SPIIORUS.
the various parts of pewter articles with soft solder,
a blast of hot air from a small charcoal furnace
affords sufficient heat. [See Sonnnnrna] Pewter
is also made in the form of sheets, for engraving cheap
music, the softness of the metal allowing the notes to
be formed by means of punches, instead of the more
elegant, accurate, but slower method of engraving
with a burin.
Pewter wares are seldom polished, but when
finished by the turning tool or scraper, are burnished
with oil, which is removed with a rag and whiting.
Pewter vessels are best cleaned by means of silver
sand and water, or with solutions of potash or soda
to remove the grease.
Lapidaries, jewellers, watchmaker-s, &c., use laps
and polishers of pewter.
PHARMACY (qbapltdo'o'ew, meclz'cam'), the appli-
cation of chemistry to the manufacture, preparation,
and mixing of drugs and medicines.
PHAROS. See LIGHTHOUSE.
PHOSPIIORUS derives its name from its pro-
perty of shining in the dark (eras, light, and qtépew, to
bear).
(P 32), and is found in the three kingdoms of nature,
chiefly in the form of phosphoric acid united with
various bases. In this state it occurs in the ancient
unstratified rocks, and in modern lavas. As these
crumble down into fertile soil, the phosphates are
taken up by plants, and are thus introduced as food
into the bodies of animals. The earthy phosphates
communicate stiffness and inflexibilityto the bones
of animals, and are of great importance. in the animal
economy.
Phosphorus was discovered in 1669-, by Brandt, a
merchant of Hamburg, while attempting to obtain.
from urine a liquid capable of transmuting silver into
gold. Kunckel, a German chemist, detected the
source of the new substance, informed Kraft’ of
Dresden thereof, and he proceeded to Hamburg to
learn the details of the process for which he paid
200 dollars. In the meantime, however, Kunckel
had prepared and described phosphorus. In 1680 it
was noticed in the Philosophical Transactions of the
Royal Society of London; and it was soon after pre-
pared. in considerable quantities‘ by Hankwitz, under
the direction of Boyle, as noticed in our article
MATCHES. In 1737, the French Government pur-
chased and published a method of preparing phos-
phorus from urine, by which it appears that 5
hogsheads of that liquid yielded only 4101111865 of
phosphorus. This disgusting process was abandoned
when it was discovered that phosphorus enters-into
the-composition of bones. A method was therefore
contrived and perfected by various chemists of emi-
obtaining phosphorus in large quantities
fronrnbones;v - The following is a sketch of the process,
actually adapted, '
r awfully. reamed in was; ‘we
1
air, in. which operation the .organic portions, .are de-
stroyed,nand escape in ‘the’ 'form of gaseous products‘. I
reviewer Whieill I remains‘ is a main. 9.5. $1,113.61?
phosphate of lime, and carbonate of lime. -.~It.~yields.
It is an important elementary substance.

about 13 or 14: per cent. of phosphorus, but pro—
bably contains as much as 17. To every 3 parts by
weight of this bone earth are added 2 parts of
sulphuric acid, and 15 to 20 of water; the whole
is well stirred up, and left for 241 hours. The
sulphuric acid decomposes the carbonate of lime,
forms a solid sulphate of lime therewith, and dis-
engages thecarbonic acid. The sulphuric acid also
acts on the, superphosplhate of lime, but does not en-
tirely decompose it; it takes up from it a portion of
lime, andleaves the phosphate in the state of an acid
phosphate of lime, very soluble in water, while the
sulphate of lime is scarcely soluble at all. The two
salts are separated by pouring the whole into a
conical linen bag of close texture, which retains the
sulphate of lime, and, allows the solution of acid
phosphate to pass through. The. mass is pressed, to
free it more completely of the soluble portion. The
filtered solution is evaporated in a copper boiler to
the consistence of a syrup; powdered charcoal is
then added in small portions, and the mass after
being evaporated to dryness, is further dried at a red
heat. This substance is put into an earthen retort,
coated with luting on the outside, to defend it from the
too fierce action of the fire. The neck of the retort fits
into the tubulure of a copper receiver half filled with
water, and furnished with a tube for the escape of the
gas formed during the distillation. In operating on
the large scale, a number of these retorts are arranged
side by side, in a reverberatory furnace. Each retort
has its own receiver, and all the receivers stand in a
trough filled with water, at the temperature of about
Ill)", and kept at that temperature in order that the
phosphorus in distilling over, may not solidify and
obstruct the tubulure. The superphos-phate of lime,
although dried at a high temperature, retains chemi-
cally combined water, which is liberated by the
superior heat of the f urnace; and at the moment of
being set free, coming in contact with the incan-
descent carbon, is decomposed,: producing hydrogen
gas and carbonic oxide. The superphosphate of lime
is decomposed into basic phosphate of lime, which
remains, unchanged; and phosphoric, ‘acid, which, in
contact with the incandescenthcarbon, yields phos-
phorus, carbonic oxide, and phosphuretted hydrogen,
the last infiaming spontaneouslyonapassing into the
air. The phosphorus distils .over, and condenses, in
the liquid form int-he tubulure, and there remains in
the-retort sub-phosphateof limeendcharcoal which
was in .the firstinstance. added’ in excess. The phos:
phorus is-purifiedabysbeing forced through chamois
leather,~and~is cast‘intosti'cks for .sale by-one of the
methods hereafter described. Phosphorus may also
be further purified by distillation. - '
Thereare'iother methods of procuring phosphorus
froml-bones. ‘One. methodyby Wohler, is to calcine-
' two ‘parts of ivorylbl'ack (which is a mixture of-phos-r
_ phate ‘Ofliqliéfandgcharcoal) with one offine' gear/1,55,
sand, and a little ordinary charcoal in cylinders-0f;
clay; at a very high temperature. Each cylinder
is ,lfit‘tedlwith. a'lbent" copper tube, one. branGhof'which"
,_ descends» into a vessel of water; .In thispltoeefilsiilhieijl
PHOSPHORUS.
387
silica acts as an acid, and combines with the lime of
the phosphate at a high temperature; while the
liberated phosphoric acid is decomposed by the
carbon. We are, however, assured by an experienced
chemist that this process cannot be pushed to com-
pletion, as the retort melts at the needful heat before
the phosphorus has distilled over.
Pure phosphorus at ordinary temperatures resembles
wax, and like it is soft and flexible; at the tempera-
ture of 32° it is hard and brittle. Its density is
1'77, and that of its vapour 4x326, air being unity.
It melts at 108°, and boils at 550°. It is not
soluble in water, and hence, on account of its great
inflammability, it is preserved under that fluid. It
dissolves sparingly in absolute alcohol, in ether, oils,
naphtha, and most of the liquid hydrocarbons, and
abundantly in sulphuret of carbon. By evaporating a
solution of phosphorus in the last-named substance,
it may be obtained in rhombic dodecahedrons. By
exposure to light, even under water, it loses its trans-
parency, and becomes yellowish; so that the bottle
containing it is usually kept in a case of tinned iron,
for the sake of opacity as well as security. By ex"
posure to the direct rays of the sun it becomes red,
even in vacuo; ‘which proves that the change is
merely molecular, and not due to chemical combina-
tion. If heated to 14¢0° and suddenly cooled, it
sometimes turns black.
Phosphorus has so great an aifinity for oxygen,
that by simple exposure to the air at ordinary
temperatures, it undergoes a slow combustion, ex-
haling a vapour, luminous in the dark, and having
an odour resembling garlic. The luminousness. of
phosphorus is so excellent a test of its presence,
that if a very minute proportion be dissolved in
sulphuret of carbon, and a drop of the solution be
placed on a hot plate in the dark, the presence of
1L,fgooth part of phosphorus is readily detected. A
stick of phosphorus if exposed for a sufficient
length of time, entirely disappears in this vapour.
The absorption of oxygen during the process may be
proved by floating a small dish containing phosphorus
11 ‘water, and covering it with a bell-glass. The
oxygen will gradually ‘disappear, and water will rise
in the glass to take its place. Indeed, this is one of
the methods of determining the quantity of oxygen
in air or other gaseous mixture, the glass standing
over mercury instead of water. [See EUDIOMETER]
It appears, however, that in oxygen gas there is
little or no absorption at temperatures below 80°,
but if the pressure be diminished to ath, or -,%th of
that of the ‘ atmosphere, the phosphorus will imme-
diately become luminous in the dark, and oxygen be
absorbed. Or if the density of the oxygen be
reduced by mixing it with nitrogen, hydrogen, or
carbonic acid, the phosphorus becomes luminous.
The slow combustion of phosphorus is also prevented
by minute portions of‘ certain gases and vapours in
the volume of confined air. Thus at 66° 1 volume
of olefiant gas in 4150 volumes of air; 1 of ether
vapour in 150 volumes of air"; 1 of naphtha vapour in
1820, and 1 of vapour of turpentine in 4444: volumes

of air, prevented the slow combustion of the phos-
phorus. Even at much higher temperatures a
certain proportion of these vapours prevented the
eflect 5 but on diminishing the pressure the phospho-
rus became luminous. Professor Graham, to whom
these experiments are due, supposes that the gases
and vapours in question are themselves undergoing a
slow oxidation, for when 2 oxidizable bodies are in
contact, one of them often takes precedence in com-
bining with oxygen to the entire exclusion of the
other.
When phosphorus is heated to about 140° it takes
fire, if perfectly dry it will ignite at a very much
lower temperature by mere exposure; a moderate
friction is also sufficient for the purpose, and it will
even take fire if left on a woollen cloth or other
badly conducting substance. The ease with which it
ignites by gentle friction, makes it dangerous to handle
except under water. When it comes in contact with
the hands in an ignited state, it produces deep and
dangerous wounds, which are long and difficult to
heal. When the phosphorus burns with flame in
oxygen or atmospheric air, the product of combustion
is a white deliquescent powder, which is phosphoric
acid, PO55 but when the phosphorus undergoes
slow combustion in contact with air at the ordinary
temperature, it undergoes a lower degree of oxidation
and forms phosphorous acid P03, In addition to these
compounds of phosphorus and oxygen there are two
others z—auz'de of phosphorus P20, and hypophos-
phorous acid P0.
The wide ofphosphorus may be formed by directing
a stream of oxygen gas‘ upon phosphorus, melted
below the surface of hot water. Vivid combustion
ensues, and the phosphorus is converted into phos~
phoric acid and a red pulverulent oxide.‘ When pure
this oxide is a red or yellow powder, according to its
state of division. It is insoluble in water, ether,
alcohol, or oils, and is decomposed by heat ‘into
phosphorus and phosphoric acid.
Hypophosphorous acid is one of the substances
formed when phosphuret of calcium [See LIME] or of
barium is thrown into water. A portion of the
water is decomposed, forming phosphuretted hydrogen
P113 (which rising in bubbles to the surface, ignites
on coming in contact with the air, forming beautiful
rings of phosphoric acid, which float away, expanding
until they disappear) phosphoric acid, hypophosphorous
acid and lime, or baryta. The soluble hypophosphite
is separated by filtration from the insoluble phosphate,
and on precipitating the base by the addition of
sulphuric acid, the hypophosphorous acid is obtained
in solution, and may be reduced to the consistence of
a syrup by evaporation. This acid is a powerful
deoxidizing agent ; it forms with bases hypophosphz'ies
which are soluble in water, and mostly deliquescent
and uncrystallizable.
Phoqphorous acid is formed as already noticed, by
the slow combustion of phosphorus in the air, or

(1) Schrtitter insists that there is no oxide of phosphorus; he
would call this red powder, amorphous phosphorous.
002
388
PHOSPHORUS.
by burning it by means of a very limited supply of
air, when it forms an anhydrous white powder. The
hydrated acid may be formed by adding water to the
terculoride of phosphorus, in which case the oxygen
of the water passes over to the phosphorus, forming
phosphorous acid, and its hydrogen to the chlorine,
forming hydrochloric acid, which may be expelled by
heat, and the residue crystallizes on cooling. Phos-
phorous acid dissolves rapidly in water; it has a sour
taste, and forms with certain bases a class of salts
termed pizosp/n'les.
.P/zosp/zom'c acid is formed by burning phosphorus
in a vessel supplied with dry air; the anhydrous acid
forms in white snow-like flakes, which have a strong
attraction for moisture, deliquescing immediately on
exposure to air, and when thrown into water com—
bining with it with a hissing noise. The water
cannot be expelled from the hydrate. Phosphorus
may also be oxidized to its maximum by heating it
in nitric acid ; but the action is very violent and
requires caution, except when amorphous phosphorus
is used, when there is no difficulty. By distilling off
the greater part of the acid, and heating the residue in
a platinum vessel, the hydrated acid may be obtained
pure, forming what is termed glacial phosphoric acid,
from its resemblance to glass. Phosphoric acid may
also be prepared from the acid phosphate of lime pro-
duced by the action of sulphuric acid on bone earth.
The phosphoric acid is precipitated by carbonate of
ammonia, the insoluble lime salt is separated by
filtration, and the filtered liquid containing phosphate
and sulphate of ammonia is evaporated and ignited
in a platinum crucible ; hydrated phosphoric acid
alone remains.
Phosphoric acid is a powerful and intensely sour
acid: it forms with bases an important class of salts
termed pizosp/znles. This acid and its compounds are
of great interest to the chemist, from the remarkable
changes which they undergo by the action of heat.
We now return to the subject of phosphorus, for
which there is an enormous demand for the manufac-
ture of lucifer matches [see MATCHES], and such has
been the effect of this demand on the price, that it
is now supplied wholesale under llzree s/n'llz'ngs per
pound; whereas, the manufacturer who first supplied
it to the London makers of matches, and who is now
living, obtained four gnz'neas per pound for it. Some
calculations as to the actual quantity consumed in
England in this manufacture will be given fur-
ther on.
We have already stated that phosphorus is sent
into the market in the form of sticks; in its fused
state it is moulded to this form by being poured into
glass tubes, and when solid forced out by means of
wires. A better method has been contrived by I-Ierr
Shubert. In his apparatus the melted phosphorus is
made to flow from a copper receiver into horizontal
glass. tubes, one extremity of each tube being sur-
rounded by water heated above 111° Fahr. and the
other extremity by cold water. The phosphorus when
solid is removed from the tube, and thus leaves space
for a fresh supply. The apparatus consists of a small

copper boiler 6, Fig. 1595, mounted in brick work,
and heated from below. On one side is a horizontal
Fig. 1595.


canal Is, also of copper, but open at the top, the
further extremity of which opens into a cistern 0; the
canal is divided into two compartments by a movable
partition p, through which the moulding tubes pass.
The boiler contains a second vessel of tinned copper
f, funnel-shaped, with a horizontal tube furnished with
a metal stop-cock s, the horizontal section of which is
shown in Fig. 1596. A copper plate pp is screwed
tightly on the wide aper-
ture of the cock 0 0 ,- it
has 2 perforations to re-
ccive the copper tubes H,
which are about 2 inches
in length, and into which
glass tubes g about 1
foot in length are in—
serted. The cistern 0
receives the sticks of phosphorus when formed,
and is furnished with a cover to exclude the light.
In making the sticks the cock s is closed, and
the vessel f filled with water. Pieces of phosphorus
are then put in, and these are melted by heating the
water bath 6. The operator sits in the space between
the cistern and the wall, and by suddenly opening
and closing the cook, a small quantity of phosphorus
passes through the glass tubes into the cold water as,
and closes them. The rough piece of phosphorus
which projects into the water from the ends of the
tubes is used as a handle for drawing out the sticks.
The cock may now be left open, and the phosphorus
drawn alternately from either tube, being from time
to time out off with a strong pair of scissors and
allowed to fall into the cistern. In this way from
15 to 20 lbs. of phosphorus may be moulded into
sticks in less than a quarter of an hour.1 If the
phosphorus is pure it may be very possible to draw
it out in a continuous stick by machinery.
In our Inrnonnc'ronr Essxr, p. cxxxviii, is a short
notice of a remarkable form of phosphorus discovered
by Schrotter, of Vienna, and known as allolropz'c or
real phosphorus,2 which is as remarkable for negative
properties as the common phosphorus is for positive
ones. We also stated in our article MATCHES the
desirability of introducing this new form of phosphorus


Fig. 1596.

(1) Annalen der Chimie und Pharmacie, quoted in the Pharma~
ceutical Journal, v01. iv.
(2) Professor Schrotter’s Memoir on this subject will be found in
the Annales de Chimie, vol. xxiv. New Series.
PHOSPHORUS.
389
into the manufacture. It is now our duty to examine
this subject in detail, and we propose to statefirst,
the method of producing red phosphorus in large
quantities, and secondly, its claims to supersede com-
mon phosphorus in the making of matches.
In July, 1851, a patent was granted to Arthur
Albright, of Birmingham, for “Improvements in the
Manufacture of Phosphorus and in the Apparatus to
be used therein,” the invention of Professor Anton
Schrotter, of Vienna; and from the specification
dated 16th January, 1852, we obtain the following
particulars :—
The invention consists in a mode of producing
phosphorus in an amorphous or non-crystalline state,
differing both in its nature and properties from the
ordinary phosphorus of commerce. The latter is
crystalline in formation, of a pale yellow colour, ap-
proaching, when pure, to a white, nearly transparent,
luminous in the dark, and burning in the open air at
a temperature of about 148° Fah. The amorphous
phosphorus, on the contrary, is opaque, of a varying
red colour, is not luminous in the dark, does not take
fire when exposed to an ordinary atmosphere, nor even
by friction or percussion, unless the temperature pro-
duced thereby exceed 46410 Fah., the ordinary tem-
perature at which this amorphous phosphorus is
inflammable being about 482° Fah., but when com-
bined with chlorate of potass or other appropriate
materials, it inflames with great energy, and may
therefore be used in the manufacture of lucifer matches
and other instantaneous igniters. It is, moreover,
free from those pernicious qualities which render the
application of ordinary phosphorus to these last-
named purposes so dangerous to health. In a com-
mercial point of view the amorphous phosphorus
possesses a great advantage over the crystalline, in-
as much as the former may be transported with perfect
safety, while the carriage of the ordinary phosphorus
is attended with considerable trouble and risk, and
consequent expense. By this conversion of condition
the phosphorus is deprived of its poisonous quality,
and of much of the peculiar and unpleasant smell
which arises from the common article, neither is it
so liable in warm temperatures to become converted
into phosphoric acid.
Ordinary manufactured phosphorus is used for
conversion into the new state, and the apparatus em-
ployed for the purpose is represented in vertical
section Fig. 1597, and in plan Fig. 1598. AA is a
cast-iron vessel, set in brick-work, with a fire-place
beneath. From the inside of the flange of this vessel
a similar vessel B B, of the same material is sus-
pended, and made fast by means of the screw-pins I I.
The space between the two vessels contains a metallic
bath, composed of a mixture of tin and lead in equal
parts. e is a cast-iron cover to the inner vessel B
fitting the top edge by means of a groove, and fastened
to the outer vessel A, by the screw-pins, HE. Ascrew
r passes through a 3-armed iron-holder L L, which is
made fast to a third movable iron vessel c c, placed
in a sand-bath shown by N N. In the interior of this
iron vessel 0 0, another vessel of glass or porcelain,

n n, is fitted, in which the phosphorus to be operated
on is placed. J is a curved pipe of iron or copper
passing freely through the cover, G, but screwed into
the cover, E, and having an exit at the extremity into


a detached vessel K K. This contains mercury or
water. If the" first be employed it is well to cover it
with water. This pipe J, acts as a safety-valve, the
metal or water in the vessel K K, preventing the return
of the atmospheric air into the inner vessel 0 c. w is
a spirit-lamp, placed, if it is necessary, under the pipe


Fig. 1598.
J, for the purpose of keeping the same hot, to prevent
clogging of the pipe by the condensation of distilled
phosphorus. X is a stop-cock to prevent the ingress
into C c of the contents of KK, or of the atmospheric
air, and should be closed before the apparatus in the
furnace is allowed to cool down, or the vessel K K is
removed.
The cover G is not essentially necessary, but is used
chiefly as a means of preventing accidents. Between
the end of the screw 1‘ and the cover E, a small but
strong concave disc or spring of steel should be in-
serted, and so adjusted as to give a slight play to the
cover B, in case of violent action arising in the inte-
rior, or the stopping up of the pipe J. Neither of
these accidents is likely to occur if the operation is
conducted with proper attention. The whole appa-
ratus as represented, is set in brick-work, with suit-
sec
PHOSPHORUS.
able furnace and fines r r for the purpose of heating
it, and maintaining the temperature required for the
process ; the phosphorus to be converted into an
amorphous state is to be previously melted and cooled
under water, and dried as much as possible. The mode
of operation is then as follows: The cover of the
inner vessel is to be raised, the phosphorus deposited,
and the covers E and e replaced. ,A fire is then lighted
under the outer vessel A n,- and the temperature raised
to such a degree as shall be sufiicient to drive off the
air and also the gaseswhich may be generated in the
interior vessel: these will escape fat the exit of .the
pipe J, which dips into quicksilver or water in the
vessel xx. The action of water inpthe vessel kn,
when ‘quicksilver is employed, is: usefuL'in ‘order that
any phosphorus which may distil over and pass down
the pipe J, may be covered thereby. The temperature
is to be gradually raised, until bubbles escape at the
end of the pipe J, which take fire as they enter the “air.
When these bubbles _ have ‘escaped freely for some
time, the temperature may raised, until ‘it has
attained a point of 500° In order to judge of
the temperature a thermometer is placed in the
metallic bath before described. ,The temperattu‘e
must be maintained fora ‘certain time, the length of
which‘ depends so mucli on accompanying circum-
stances, that it can only be determined by experience,
at a point within a few degrees of the beforesmentioned
elevation, perhaps rather higher than lower. As ‘soon
as the phosphorus is converted into an amorphous
state, the vessel may be allowed to cool down. The
phosphorus is then taken out, to effect which it may
be necessary to break the glass or porcelain vessel.
It ‘may be desirable to increase the pressure on the
vessel 0 c and n n, and for this purpose the vessel x K
should be deepened, so as to contain more mercury,
and by this means a prdssure of an atmosphere or
even more may be gained. In this case it will be
necessary to remove the disc or spring so soon as the
steam and fiery bubbles which arise inthe first part
of the process have ceased to appear at the end of the
pipe J.
The phosphorus is then to be levigated under water,
from which it may be drained by being placed in a
bag or on a filter. If the operation has been success-
fully conducted, the amorphous phosphorus produced
contains only very slight traces of common phospho-
rus. The levigated phosphorus, while moist, should,
in order to purify it, be then spread thinly for conve-
nient working on separate shallow trays of sheet-iron
or lead, and these trays can be so placed alongside
each other as to receive the heat of steam, or of a
heated .bath of water, or of chloride of calcium, or of
sand, or’. of each consecutively, in this order; but
whicheyer be employed, the temperature must be
raisedgradually, and the phosphorus frequently stirred
until the disappearance in the dark of all luminous
vapour shall show that the whole of the adhering
crystalline phosphorus has become oxidized.‘ The
operator should have water at hand to quench any
(1) The manufacturers state that this process is found tedious
and. very difficult, andis-superseded by the use of an appropriate

fire that might arise before the whole mass was per-
fectly oxidized. When the process of purification is
thus far completed, the phosphorus must be washed
until the water in which it is so washed shows no
trace of acid when tested. In case the amorphous
phosphorus produced contain too large a proportion
of unconverted phosphorus, the latter may be washed
out by means of bisulphuret of carbon.
In the above process the temperature must be
carefully regulated, for if too high, a powerful explosion
will take place inlconsequence of the amorphous
phosphorus being suddenly reconverted into ordinary
phosphorus, and that again into a highly elastic
vapour. If we suppose the thawing point of ice (32°)
and the boiling point of water (212°) to approach
each other very nearly, a similar efiect might be ex-
pected on applying heat to ice. This liability to
explosion required the apparatus to be made very
strong and secure, and it has happened that many
days produce of amorphous phosphorus has by a sud-
den explosion been entirely reconverted into common
phosphorus. ,
The amorphous phosphorus occurs in several forms
according to its position in the converting vessel D I),
and the subsequent purification. Those portions
which are but partially pure will ignite when struck
with the edge of a knife. The purer lumps will bear
a high temperature, and holding to the fire without
inflaming. The purest of all may be dipped into
sulphuret of carbon or spirits of wine, and being
- ignited the spirit will all burn off without setting the
phosphorus on fire.
The lumps are occasionally of a bright scarlet
colour, but usually of a dark purple red 5 some are
heavy with a metallic aspect; some light, almost like
pumice-stone in the handling, and very friable. In
the formation of the latter the amorphous phosphorus
was probably partially formed, and the common phos-
phorus distilled out of it, leaving the porous mass.
Some of the lumps are light enough to float on
water.
The great practical value of this scientific discovery,
arises from the fact that phosphorus in this state is
not. injurious to the persons engaged in the manu-
facture of lucifer matches. The dreadful disease to
which these persons are liable, would be supposed to
be a suificient inducement to manufacturers at once
to resort to the new and innocuous form in preference
to the old and dangerous form of the element in
question, provided were capable of being applied
with the same efficacious results; and it might be
reasonably supposed that the public would patronise
the new matches, not only on the score of humanity,
but also ‘on account of the increased safety which
pertains to the amorphous phosphorus matches. But
as a writer on thissubject in the Pharmaceutical
Journal (September 1852) well observes, “it is dif-
ficult to introduce. any innovation of this kind into
an extensive branch of manufacture. A series of
experimentsimust be made to test the efficacy of the
solvent, by which .all the adhering ordinary phosphorus is easily
and. quickly eliminated. _
PHOSPHORUS.
as
new preparation, the most advantageous mode of
employing it, the quality of the goods and the
economy of the process. ‘In the meantime the several
departments of the manufactory are progressing like
clock-work. All hands are busily employed, the pro-
prietor is fully occupied with superintending the
operations and the accounts, and a large box of
amorphous phosphorus remains in the oilice un-
packed, waiting for a convenient opportunity to com-
plete the experiments.”
In order to place in a strong light the evils result-
ing from the use of common phosphorus, we will state
a few particulars respecting the jaw disease. In the
Dublin Quarterly Journal of Medical Science for
August 1852, the nature of the disease is thus de-
scribed by Mr. Harrison:—“ An affection ensues
which is so insidious in its nature, that it is at first
supposed to be common tooth-ache, and a most
serious disease of the jaw is produced before the
patient is fully aware of his condition. The disease
gradually creeps on until the sufferer becomes a
miserable and loathsome object, spending the best
period of his life in the wards of a public hospital.
Many patients have died of the disease; many unable
to open their jaws have lingered with carious and
necrosed bones; others have suffered dreadful mutila~
tions from surgical operations, considering themselves
happy to escape with the loss of the greater portion
of the lower jaw.” 1 It is stated that the diseased
bone has a spongy cellular appearance with excres-
cences of a similar character adhering to it; that the
teeth generally continue sound and white, while the
jaw which contains them is altered in texture, dead
and discoloured. At Mr. Dixon’s manufactory at
Newton Heath near Manchester, many persons who
have suffered from the disease and recovered, have
returned to their work, but not to the clipping depart-
ment. Doubtless the poor people had no other
employment to turn to on leaving the hospital. “In
the museum of the Manchester Infirmary is the lower
jaw of a young woman who is now at work. Her
face is much disfigured by the loss of her chin, and
on looking into her mouth, the root of the tongue is
seen connected with her under lip, the space formerly
occupied by the aw being obliterated by the contrac-
tion of the cheek. A young man who has lost his
jaw is also in the factory. These are not isolated


cases. It is stated in the factory that the work-
people have sometimes applied the phosphorus paste
to decayed teeth, under the idea that it was a cure
for the tooth-ache, and to this imprudence some of
the early cases of the disease are attributed. The
frightful nature of the disorder is now sulficiently
understood to serve as an incentive to greater pre-
caution. Increased attention has been paid to ven-
tilation and cleanliness, and the practice of taking
meals on the premises is not allowed. It appears,
however, from the statements of some of the work-
people who are engaged in the phosphorus dipping
room, that their clothes become incandescent in the
dark, and although the cases of the disease are less
frequent than they have been formerly, a security
against its recurrence is not attained.” ‘We have
been assured by a manufacturer, that the palm of the
hand of a child employed‘in simply placing the covers
on the boxes when filled with matches, will be found
luminous in the dark.2
Various attempts have been made to remedy the
evil. Camphor has been added to the composition:
it conceals the smell and is said to act as a prophy-
lactic. It has been suggested to expose oil of tur—
pentine in saucers about the workrooms as a solvent
for the fumes of phosphorus. A sponge moistened
with a solution of soda or potash tied over the mouth
has also been used, and it is recommended to the
clippers to use a mask with a tube communicating
with the external air. The quantity of phosphorus
employed in the paste has been greatly diminished;
but all these expedients only serve to mitigate the
evil, and all of them except the last are attended
with an increase of expense. Manufacturers will
not use camphor or turpentine, even if they could be
proved to be efficacious in getting rid of the fumes,
which we much doubt; and even if the masters found
thc means the work-people would neglect them, and
even if the larger manufacturers would take all need-
ful precautions, there are a great many small ones,
whose children Work in London garrets, who Will
never be cared for.
To ensure the general introduction of the new phos-
phorus it is only required that some enterprising manus-
facturer should employ it in his matches, make the
public understand its merits, and that he will use no
other: any slight increase of cost (and we are as-
sured it will be but slight) will he more than covered
by the patronage that will be extended to him, and
other makers must follow his example. There are;
we know, several manufacturers who are so desirous
to preserve their workpeople from the dangerous ten—
dencies of the old phosphorus, that we believe when
some further investigations shall have discovered the
best and most economical adaptation of the new kind
to their object, they will rejoice (even if in the first
instance at some small pecuniary sacrifice) to avail
themselves of its discovery, and when this point is

(1) The history, nature, treatment, 8zc., of the disease is very
fully investigated in a German work entitled, “ Die Krankheiten
der Arbeiter in den Phesphorzii'ndholzfabriken insbesondere das
Leiden der Kieferknochen dureh Phosphord’aimpfe. Vom Che-
misch-physiologischen, medicinisch-chirurgischen und polizeyli-
chen Standpuukt bearheitet von Dr. Freiherrn Ernst von Bi‘ora
and Dr. Lor. GeisL—Erlangen, 1847.”
It appears that out of 68 cases to which attention had been-
directed, 15 deaths had occurred, 15 had recovered (some, however,
with loss of the jaw-bone), 15 remained under treatment, and the
issue of the remaining 21 cases was unknown.
The disease spares neither age nor sex, nor does it require any
very long exposure to produce its efi‘ects, for these have been de-
veloped in a marked form in cases where the persons employed
did not touch the matches, but were engaged in adjoining rooms
preparing the wood or making the boxes. It has been known to
attack those engaged in overlooking the factory, and in some cases
it has appeared long after the individuals had left the employment.
(2) It is stated that the authorities of Erfurt, in Prussia, require
a periodical visitation of the match factories, with a view to the
dismissal of all who are found to have unsound teeth.
392
PHOSPHORUS.
gained, the interests of humanity would seem to re-
quire that the use of the old article should be aban-
doned, if not prohibited.1
The objections to matches made with common
phosphorus are numerous: they are luminous in the
dark,2 they have an offensive smell, they are poisonous
(children have been killed by sucking the matches,
and we have heard of jaw disease being produced by
children playing with them); fires have been produced
by their spontaneous ignition; they contract damp from
the air, and lose their property of igniting by age.
Matches made with the new phosphorus produce
no light in the dark under 400° ; they have no smell,
are not liable to contract damp, and may be placed on
‘a hot mantle-shelf without taking fire : they are thus
adapted to moist and hot climates, and will keep for
any length of time without change. The Editor has
in his possession samples of matches, made in 1851,
by different manufacturers, containing a large propor-
tion of amorphous phosphorus; they act well, and
appear to be wholly unchanged by time.
The extensive diffusion of common phosphorus in
the composition with which lucifers are tipped, must
have some injurious action on the health of all per-
sons, for there is, probably, not a house in Europe or
America, scarcely a room, that has not its box of lucifer
or congreve matches. It is only this general demand
that at all accounts for the enormous production of
the match factories at home and abroad. At Messrs.
Dixon 85 Co.’s factory, Newton Heath, from 450 to
500 persons are employed. The average daily pro-
duction of the finished article varies from 6 to
9,000,000. The usual weekly average is 43,000,000,
and allowing 50 weeks to the year, the annual pro-
duction of this single factory is 2,160,000,000. Taking
the population of the British Islands at 30,000,000,
we have an allowance of 7 2 ‘matches for every man,
woman, and child. Such also is the cheap rate with
which matches are produced, that 14,400 matches in
144: boxes can be sold wholesale for the small sum of
sixteenpence, even when made and paid for at the
English rates of labour.
In and previous to the year 184A, the whole of the
phosphorus consumed in this country was imported
from abroad. The amount of duty paid showed a
consumption of about 14,000 lbs., and it is the opinion
of Messrs. Sturge of Birmingham,3 (who are large

(1) Messrs. Dixon assure us that they are anxious to adopt
every available means that may be conducive to the health and
comfort of their workpeople, and that if they have not yet
made use of the amorphous phosphorus in the manufacture of
lucifer matches, it is simply because they have not been able to
make it succeed. “ Whatever future results may arise from
further experiments we cannot pretend to say, but trust to che-
mical science to remove the dreadful disease arising from the use
of the present phosphorus.” 7th February, 1853.
(2) We have already stated how minute a quantity of common
phosphorus may be detected by its luminous property. Should
the red phosphorus come into general use in the manufacture of
matches, the manufacturer will not be able without detection to
employ the old phosphorus for the new, since a single grain of the
former mixed with 1,000 grains of glue thinned with water will
shine when gently heated, and if applied to matches will become
luminous by the warmth of the hand.
(3) We have to express our obligations to these gentlemen, as well
as to Mr. Albright, for much valuable information in this article.

manufacturers and exporters of phosphorus, and are
at present engaged in working the patent for the
red phosphorus,) that the consumption has not
greatly increased since that time. The constant re-
duction in the price of matches has naturally led to
repeated diminutions in the proportion of phosphorus,
the most expensive ingredient in the dipping com-
position; to which it is very likely the fear of the
phosphorus disease has also, in recent times, contri-
buted. Most of the English makers have continued
to use chlorate of potash after it had been much dis_
used in Germany; and the very low price at which
this salt can now be purchased has favoured its in-
creased employment to the diminution of that of
phosphorus.
The number of persons engaged in the manufacture
in England must be considerably over 2,000. In
addition to the large manufactory near Manchester,
and smaller ones in other towns, there are at least
‘is considerable makers in London and its vicinity, and
a very large number of small makers, the consump-
tion of whose wares in London alone is very great.
On the continent of Europe the extent and economy
of the manufacture are also most remarkable. Manu-
factories of phosphorus are to be found in France,
Prussia, Baden, Bavaria, Austria, Sardinia, but only
within the last few years in England. Manufactories
of matches have spread all over Europe, from Tran-
sylvania on the borders of Turkey, and near the Black
Sea, to the inland lakes of Sweden, and the Finland
shore of the Gulf of Bothnia. In the United States
of America and in Central America these factories
are also to be found. The export manufacture of
Germany is being continually extended on accomit of
the abundance and cheapness of timber and of labour,
and the preparation by the poor in winter of the
turned wooden boxes for containing the matches. In
order to encourage the industrial habits of the poor,
the Government in Hanover, and probably in other
parts, supports the manufacture by giving the wood
out of its forests at a merely nominal price, a huge
pile of billets being sold for a few pence. At Darin-
stadt, Nuremberg, in Bavaria, at Ulm and Gmund,
in Wurtemberg, are very large manufactories, two of
them making more than 6,000,000 matches per diem.
The German manufacturers have their agents in this
country, and large quantities of matches are imported
into Hull and London, and being well packed in cheap
but substantial cases, they are carried by the rail-
way companies as Toys, while the produce of our
own manufactories is as a general rule refused to be
conveyed.
Assuming, as is done in the Jury Report [see
Mn'rcnns], that Austria manufactures 50,000 cwt. of
matches, the quantity produced in Europe probably
exceeds 200,000 cwt. per annum. It would require
100 merchant vessels of average tonnage to accommo-
date this quantity as cargo. It is estimated also in
the Jury Report, by_M. Payen, that 30,000 kilo-
grammes (590 cwt.) of phosphorus for matches are
annually consumed in France. Professor Schriitter
mentions in connexion with the Paris Exhibition of
PHOTOGRAPHY. 393
18419, that one maker produced 3,000 kilogrammes
of phosphorus monthly; but a large proportion of
this was for exportation. It has since much increased,
and we believe that the conjoined English and French
product of phosphorus would in 1853 be little short
of 300,000 lbs. per annum. A German manufacturer
informs Messrs. Sturge that 3lbs. of phosphorus
suflice for from 5 to 6 million matches of German
make. If we divide 300,000 by 3, and multiply by
5 millions, we thus get 500,000 millions of matches
as the annual product consequent on the consump-
tion of the French and English phosphorus.
PHOTOGRAPHY is the art of drawing or pro-
ducing pictures, or copies of objects, by the action of
light (qba'is‘, light) upon certain chemical preparations.
Of late years the action of the chemical rays of the
solar spectrum has been much studied, and the varied
and beautiful phenomena presented thereby have been
included in a distinct branch of science, termed
Adina-chemistry, or simply aez‘z'm'shz, which means my-
pozeer. This includes all those varied effects to which
have been applied the terms, Daguerreolype, and
Tellholype (from Daguerre and Tellhol, the names of
the founders of the art of producing sun pictures);
and also pholography, or drawing by light‘, and hello-
gmphy, or drawing by the sun ; Chrysoz‘ype, in which
iron and gold are employed; Q/emolype, in which im-
pressions are produced by the salts of iron, in combi-
nation with those of cyanogen; Ahthoz‘ype, where the
juices of the wild poppy, stock, rose, &c., are eifaced
by the action of light. We have also such terms as
Ferroz‘ype, Ehergz'alype, Chromalype, Calozfr/pe, and
many others.
The ancients seem to have been acquainted with
the fact that the colours of some of the precious
stones were affected by exposure to the rays of the
sun. The alchemists discovered that the horn-like
substance prepared by fusing chloride of silver
(hence called ham-silver, or lama cornea), became
black by exposure to the light. Scheele examined
the action of the difierent rays of light upon the
salts of silver; and in 1801 Ritter ascertained the
existence of invisible chemical rays beyond the limits
of the visible spectrum. Many other scientific men
recorded some interesting facts respecting the chemi-
cal action of the solar spectrum; and in 1802,
Sir Humphry Davy published in the Journal of the
Royal Institution, “ an account of a method of copy-
ing paintings upon glass, and of making profiles by the
agency of light upon nitrate of silver.” Mr. Wedg-
wood was associated with Davy in this inquiry. They
succeeded in obtaining copies on prepared leather, or
paper, of images of leaves, the wings of insects, and
other small objects, as shown by the solar micro-
scope, but they did not succeed in the drawings
on the paper. In 1814.‘, M. Niepce, of Ohalons, on
the Soane, is said to have first directed his attention
to the production of pictures by light. He pursued
his studies for about ten years, without much success,
when he became acquainted with M. Daguerre, who
had been endeavouring, by various chemical processes,
to fix the images obtained by the camera obseura.

In December, 1829, they entered into partnership, by
deed, for mutually investigating the subject. In
1827, Niepce sent a paper to the Royal Society on
the subject of his heliographical discoveries, but as
he kept his processes secret, the Society could not,
by their laws, receive his paper. The paper was
accompanied by specimens, which, however, do not
appear to have been very successful. In January,
1839, Daguerre’s discovery was announced, and the
exquisite pictures produced by him were exhibited,
but his process was not made known until the follow-
ing July, after a bill had been passed securing to him
a pension of 6,000 francs for life; and also a pension
of 4,000 francs to the son of Niepce, with one half in
reversion to their widows. On the 31st January,
1839, six months before the publication of Daguerre’s
process, Mr. Fox Talbot communicated to the Royal
Society an account of his photographic discoveries, and
in February published his method for preparing a
sensitive paper for photographic drawings. It appears
that Mr. Talbot had practised his method from the
spring of 1834, and had devised it somewhat earlier.
After the publication of the two methods, the art
was taken up by various scientific men, and a rich
crop of discoveries speedily rewarded their labours.
Sir John Herschel, writing on this subject in 1840,
says :—-“ It is no longer an insulated and anomalous
affection of certain salts of silver or gold, but one
which doubtless, in a greater or less degree, pervades
all nature, and connects itself intimately with the
mechanism by which chemical composition and de-
composition is operated. The general instability
of organic combinations might lead us to expect the
occurrence of numerous and remarkable cases of this
affection among bodies of that class, but among me-
tallic and other elements, inorganically arranged,
instances enough have aheady appeared, and more are
daily presenting themselves, to justify its extension
to all cases in which chemical elements may be sup-
posed to be combined with a certain degree of laxity,
and, so to speak, in a lollem'hg equilibrium. There can
be no doubt that the process, in a great majority, if
not in all cases which have been noticed among inor-
ganic substances, is a deoxidizing one, so far as the
more refrangible rays are concerned. It is obviously
so in the cases of gold and silver. In that of the
bichromate of potash, it is most probable that an
atom of oxygen is parted with, and so of many
others.”
This distinguished philosopher has in the course of
his inquiries enlarged the boundaries of the solar
spectrum, and laid the foundation of the new science
of actinism. Fig. 1599 exhibits the spectrum as it
is at present known. The seven colours included
between A and B, represent the spectrum as discovered
by Newton. Below the ordinary visible red is another
ray a, distinguished as the extreme red or erz'msoa ray:
this may be detected by examining the spectrum
through a deep blue glass. At the upper end of the
spectrum is the lavender ray 6, which is seen when
the spectrum is received on a sheet of yellow paper.
The curves 0 n 15 represent the relative maxima of
394:
rnoroenarirr.
izeaz‘, lip/it, and acz‘im'sm. r is a second apparent
maximum of the chemical power; hence it will be
seen that the chemical power is greatest in the violet
ray opposite to E, and ceases at d and e, slightly
increasing at r. The yellow rays destroy all actinic
power, and it is here at c that the light is most
,-" . Z_ , Lavender.
Actinism, or .1
Chemical power. R, Violet-
Indigo.
Blue.
Green.
Maximum of light. Yellow,


Orange.
Red.
1"
v‘
Maximum of heat. hula Extreme 33¢
\

Fig. 1599.
intense; it ceases at a and b. The heat is greatest
at 1), and disappears at b and c. The effect of the
yellow .rays in diminishing the actinic power, is shown
by the fact that near the equator a much longer time
is required for impressing a photograph than in
London or in Paris. Dr. Draper found that in pro-
ceeding from New York to the southern States, the
space protected from chemical change by the yellow
rays regularly increased. A similar result is found
between spring and summer; photographs being more
readily obtained in March and April, than in June
and July. The morning sun also, between 8 and
12 o’clock, produces much better effects than can
be obtained after noon.
In the preparation of photographs the chemical rays
of the spectrum form the pencil, and certain delicate
chemical preparations on the surface of paper or of
metal the drawing board. But it is necessary that the
rays should form -an optical image upon the chemically
prepared surface, under such circumstances that no
other light shall produce any effect, except those
pencils which depict the image. For this purpose a
good camera odscuml is necessary. The principle of
this instrument was stated in the article LIGHT
[page 159 note], but it may be further illustrated
here. When the sun is shining through a small hole,
a round luminous spot will be seen on a screen placed
for thepurpose ajconsiderable distance behind it, and
this spot will increase in size as the screen is made to
recede from the hole. The spot is in fact an image,
or representation, of the face of the sun, the light from

(1') This instrument was first. described by John Baptista
Porta, in his Magic N ratumlis, published towards the end of the
fifteenth century. I " - —

every part of the sun’s disc passing-through the hole,
and continuing its course in a right line beyond it,
till it reaches the screen; so that every point in the
sun’s disc has a point corresponding to it on the
screen. So also, if a pinhole in a card be held between
a candle and a piece of white paper in a dark room,
an exact image of the flame, but inverted, will be
depicted on the paper; and this image will enlarge as
the paper recedes from the hole. If in a dark room
a white screen be extended at a few feet from a small
round hole, an exact picture of all external objects, in
their natural colours and forms, will be represented ;
moving objects being shown in motion. See Fig. 1600,


Fig. 1600.
N ow as all objects exposed to light are luminous, and
every physical point of their surface radiates light in
all directions, so every point in the screen receives
light at once from every point in the object. The
same may be said of the hole ; but the light that falls
on it passes through and continues its course in
straight lines behind. Thus the hole becomes the
vertex of a conoidal solid prolonged both ways,
having the object for its base at one end, and the
screen at the other; and the section of the solid by
the screen is the picture projected on it, which must
evidently be an exact, but inverted, representation of
the object.
The effect of these experiments is greatly improved
by the use of a convex lens of a focal length some
what less than the distance of the surface on which
the picture is projected, the images being in such
case much more vivid and distinct. Some of the
objects are, however, imperfect and ill-defined, unless
they happen to be situated at the same distance from
the aperture, because the focus of the lens cannot be
at once adjusted to near and remote objects. In the


Fig. 1601.
ordinary camera, Fig. 1601, the picture is intercepted
by a‘ plain mirror, placed at an angle of a5°to the’
bottom of the dark box, ori'camera' ‘obscure, and 1s‘
PHOTOGRAPHY.
395 '
thence thrown upwards to the surface of a plate of
ground glass, or, what is better, a film of skimmed
milk dried upon a plate of glass. For the sake of
accuracy the ground on which the picture is received
should be hollow, and part of a sphere whose radius
is the focal distance of the convex lens.
For the practice of photography, the camera should
possess “ a flat field, a sharp foeusat great inclinations
of the visual ray, and a perfect achromaticity.” The
simplest form of instrument, Fig. 1602, consists of a
wooden box, in the
front of which slides a
brass tube, containing
,- a meniscus lens Z, the
l radii of the curves of
.. ———* which are in the pro-
Fig. 1602. portion of 2 to 1; there
is also a diaphragm or stop a little way in front of it.
At the back of the box is a frame, with a piece of
ground glass for ascertaining the focus, and another
frame so constructed that the prepared paper can be
placed between a plate of glass and a smooth surface
of wood or slate, and in front of the glass is a slide to
shield the paper from the light until it is introduced
into the camera. With such an instrument as this it
must be remembered that the violet or chemical rays
focalize nearer to the lens than the more luminous
rays which produce a bright focal image, so that in
order to produce a well—defined photographic picture,
the lens must be brought towards the prepared
surface, so that the violet rays may form a focus.
Some cameras are furnished with a strip of wood or
ivory graduated both for the optical and the chemical
focus, so that the instrument can be set by measuring
the distance of the object to be copied, if near; if it
be at a distance it may be roughly calculated. An
achromatic lens is necessary, however, to the produc-
tion of finished photographs. 'Such a lens may be
single or compound; the one being usually employed
for views where a considerable time can be allowed,
and the other for portraits, which require to be taken
as quickly as possible. Fig. 1603 shows the com-
pound achromatic arrange-
ment which is screwed to
the front of the camera.
This tube is furnished with
a movable brass cap and a
series of steps or diaphragms
s, which are employed when
the lens is used for land-
scapes, and also for portraits, if the light is very bril-
liant. When a long focus lens is required, as for
views, the back lens A is removed, and the cap 0 and
the stop 8 substituted: the whole of the brass mount-
ing and the lens is reversed with respect to the
camera by the screw over the lens 1;, by which means
the lens 13 is placed within the camera, and can be
adjusted by the same rackwork. The compound lens
is always adjusted for focus by rackwork: a sliding
tube suffices for the simple lens; and, as a well-
constructed achromatic glass causes all the coloured
rays to meet at one focus, the correct adjustment will




be at thatpointwhere the object is clearly and sharply
brought out on the ground glass. This is best ascer~
tained by placing on the ground glass the ‘wide part
of a short conical tube, Fig. 1604:, furnished ;with ‘a
magnifying-glass at its upper end. The eye
can then examine any part of the image,
and thus obtain the requisite sharpness of outline. A very convenient form of camera ,_
adapted for tourists is sold by the instru- F4.
ment-makers. It is shown, ready for use, Fig. 1605,




Fig. 1605.
and is thus described by Mr. Thornthwaite:1 “The
front of the camera holding the lens has a vertical
adjustment, which enables the relative proportion of
foreground or sky in the required picture to be altered
without disturbing the position of the camera. In the
body of the camera is placed two or more openings or
slides, by which either the long focus lens for views,
or the shorter combinations for portraits, &c., can be
employed as desired. When not required for use, the
lens is unscrewed, the front and slides lifted from
their grooves, and the body of \
the camera folded together by
the hinges shown in the cut ;
by which arrangement the ca-
mera box, together with the
slides for prepared paper, glass
or silver plates, frame for
ground glass, achromatic lens,
860., can be conveniently pack-
ed, and in the smallest possible
space, as shown in the leather
case, Fig. 1606.”
A portable camera has been described by Mr. George
Stokes. It weighs only 9 lbs. with shutter, and will


Fig. 1606.
take a picture 11 inches square. Its great advantage is;
in the-shutter, which will contain from 12 to 20 pieces
of prepared paper, each piece between separate pieces
of blotting paper; and'the whole being pressed by
the front portion of the shutter, the light and air are
quite excluded. When required for use (by the
assistance of a very small hood) the first piece of
paper is placed at the back of the glass, and the im-
pression taken;,when, by removing the millboard, it
will fall back into its place; at the same time another
piece can be brought forward ready for another
picture, before focusing, and so on to the end. The
hood is made of India-rubber cloth, and also answers
the purpose of a focusing cloth, without the necessity
of removing it during the day. This shutter is of

(1) “A Guide to Photography,” 4th Edition, 1852. This con~
cise treatise is intended for the use of the amateur, but chiefly
to accompany the apparatus sold by Messrs. Home, Thornthwaite,
and Wood, of Newgate Street, London.
396
PHOTOGRAPHY.
great service, saving much time and trouble in carry-
ing several shutters.
As the camera reverses, causing objects on the
right to appear on the left in the picture, a small
reflecting mirror or prism may be used for again re-
versing the object in the camera, and thus producing
a correct result.
- We will now proceed to notice, very briefly, the
art of photography as practised upon paper. In the
first place we must remark that the selection of the
paper is a point of very great importance; for unless
it be of very uniform texture, it will not receive the
saline solutions equally, and the result will be a
spotty photograph. The best plan is to hold up the
paper, a sheet at a time, between the eye and the flame
of a lamp, and to select those sheets only which are
free from specks and water-marks, and of equal trans-
parency throughout. The cheaper kinds of demy
contain a make-weight of sulphate of lime: and some
of the varieties of enamelled satin post contain china
clay, or kaolin. These should be avoided. The pre-
sence of size does not appear to be injurious, and it
is recommended that old in preference to newly~made
paper be used, because in old paper the organic mat-
ter of the size has passed through those changes to
which it is liable, and it may be regarded as tolerably
permanent, both in composition and colour. The
French manufacture a paper expressly for the pur-
pose; but Professor Hunt1 states that it is better
adapted to French than to English photographic pro-
cesses. Mr. Thornthwaite recommends the blue wove
post manufactured by Whatman, the paper to be cut
into sheets about 9 inches by 8. In cases where
highly sensitive paper is to be prepared, it is desirable
to separate metallic and earthy matters by steeping
the -paper for some hours in water acidulated by
nitric“ acid, and then removing all traces of the acid
by leaving the paper for half an hour under gently
flowing water.
One of the simplest methods of illustrating the art
is by means of paper prepared with muriate of baryta,
10 grains dissolved in 1 ounce of distilled water; and
the solution of ammoniacal nitrate of silver, contain-
ing about 50 grains of nitrate of silver per ounce.2
These solutions may be applied to the paper by one of
three methods :--—1. A small quantity of the solution
is poured upon the surface of a flat glass plate or
earthen dish, and the paper is to be placed carefully
on the "surface in such a way as t2 prevent the forma-»
tion of air bubbles between the paper and the solution.

(1) The reader interested in the study will find a resumé of
most of the processes given in Professor Hunt’s “Photography;
a treatise on the chemical changes produced by solar radiation,
and the production of pictures from nature by the Daguerreotype,
Calotype, and other photographic processes.” 8V0. London, 1851.
(2) Mr. Alfred Smee’s instructions for preparing this compound’
are as follows :---For a two-ounce stoppled phial, place 50 grains
of crystallized nitrate of silver, and pour over it 1 ounce of dis—
tilled water. When the crystals are dissolved, some strong solu-
tion of ammonia is added, a few drops at a time, and the phial
well shaken after each addition. The whole becomes, first, of a dark
brown colour, from the formation of aprecipitate of oxide of silver;
but as soon as the proper quantity of ammonia is added, the oxide
of silver is dissolved, and the solution becomes perfectly clear, and
is ready for use.

The back must not be wetted, and it is desirable, in
the selection of the paper, to attach a small mark
with a pencil to that surface which is to be prepared,
so that it may be afterwards distinguished from the
back or unprepared surface. The paper must be
pressed gently down to the solution with a glass rod,
to prevent it from curling upwards; but when the
sheet has lost its rigidity, lies flat, and becomes slightly
opaque, .it has absorbed enough of the fluid, and may
be lifted off, allowed to drain for a few seconds, and
then hung up to a cross rail of wood by a couple of
pins. The fluid which accumulates at the bottom edge
of the suspended paper should be removed by touch-
ing it with a piece of thick filtering paper. 2. The
paper is to beplaced, with its marked side upwards,
upon a wooden board a little smaller than the paper;
a glass rod is next to be placed across the paper near
the left end; a measured portion of the solution is then
to be poured on the paper in front of the rod, which is
to be moved backwards and forwards until the paper
is properly wetted. The sheet may then be hung up
to dry. 3. The paper is to be attached at the four
corners by pins to a surface of blotting-paper, and the
solution applied by means of a soft brush, the extreme
edge being avoided; but should any of the solution
flow over the edge, it will be absorbed by the blotting—
paper, and thus the back of the paper will be pre-
served from stains. When properly moistened, the
paper may be removed and hung up to dry. An ordi-
nary brush is rapidly corroded by solutions of silver,
so that it is better to use a piece of cotton wool
attached to a glass tube instead. It will soon be dis-
covered by the behaviour of the paper which of these
three methods is to be preferred. If by the first
method the paper take up the solution unequally, the
defect may often be remedied by the friction used in
the other two methods.
Any number of sheets of paper may thus be pre-
pared on the marked surfaces, with the solution of
muriate of baryta, and when dry they may be kept
for any length of time without injury. When required
for use, a sheet of this prepared paper is to be washed
over (of course on the marked side) with the solution
of ammoniacal nitrate of silver, and hung up in a dark
cupboard to dry: it may then be preserved in a port-
folio, or between the leaves of a book, for use; it
should not, however, be kept longer than about 241
hours before being used.
The surface thus prepared soon becomes black by
exposure‘ to light, and it is obvious that if the object
to be copied be previously placed upon the prepared
surface, 'the light will act upon the uncovered portions
of the surface, tracing with minute accuracy the out-
line of the object, and even acting through its sub—
stance, if it be partially transparent or translucent,
varying the intensity of its tints with the varying
translucency ‘of the object, making them deep where
but little light is capable of passing through, deeper
where more light passes, and deepest of all on the
exposed portions. Flat objects, such as plants, leaves,
flowers, ferns, mosses, feathers, wings of insects,
pieces of lace, prints, drawings, &c., are well adapted
PHOTOGRAPHY.‘
397‘
to this method; but in order to obtain correct and
sharp outlines, the object must be pressed down upon
the paper; for which purpose a frame and glass may
be used. A convenient size for the glass is rather
larger than a single leaf of ‘Mo. post writing paper.
The glass should be thick enough to resist pressure,
and as clear'as possible. The frame is represented in
Fig. 1607, in front, taking a copy of a flower. Fig.
1608 shows the back, which has a plate of tinned
iron or wood pressing on a cushion, and secured by a
bar, the ends of which being moved into the grooves
in the sides, give the required pressure to the paper,
and bring it well into contact with the object to be

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Fig. 1607. Fig. 1608. Fig. 1609.
copied. In copying leaves of plants the upper and
smooth surface should be in contact with the prepared
paper: thick roots or buds to a plant may be thinned
down with a penknife. Fig. 1609 shows another form
of frame used for the purpose. The object being
thus prepared, and mounted in a shady room, or by
artificial light, may now be exposed to sunshine for
some minutes, depending upon the nature of the object
and the sensitiveness of the paper. If the delineation
be satisfactory, the next process is to fix it on the
paper, by removing from it that portion of the salt of
silver which still remains undecomposed. This is done
by means of a solution of hyposulphite of soda, (1 oz. to
a pint of water,) contained in a flat dish large enough
to contain the drawing. But before this solution is
used, the drawing should be placed for a few minutes
in cold water, and agitated to prevent any deposit from
forming on the surface: it must then be placed, face
upwards, in a flat dish, and some hot water be poured
over it gently, to remove the size from the paper, an
effect which is indicated by the paper becoming very
absorbent, and on inclining the dish, the water not
running down in separate streams. The drawing may
now be dried by pressing a few folds of white blotting-
paper upon its surface. It may next be laid upon the
solution of hyposulphite, face upwards, until the whole
surface appears to be well wetted by the upward ab-
sorption of the solution; it is then to be washed in
separate portions of water until the water ceases to
have the sweet taste of hyposulphite of silver. When
dried, the drawing may be exposed to light without
being injured. In this fixing process, the chloride of
silver of the prepared surface is very soluble in hypo-
sulphite of soda, while the subchloride of silver, to
which the action of the light reduces the chloride, is
not: hence, when the photogenic drawing is placed in
the hyposulphite, the undecomposed chloride of silver

is converted into hyposulphite of' silver, which, being
very soluble in water, is removed in the washing.
In a drawing thus obtained, the lights and shades
are, of course, reversed, with respect to the original;
that is, the light parts of the original produce dark
parts on the paper, and vice oersei. Such impressions
are termed negative, to distinguish them from those
in which the lights and shades are as they occur in
nature, and which are called positive photographs.
Positive impressions can be obtained from negative,
by using the latter in the frame instead of the object
itself.
We next proceed to give a brief outline of one of I
the methods of producing a higher order of photo—
graphs, viz. the Onno'rrrn. This process, or as it is
also called, the Talhotype, from the name of the
inventor, who has patented it, produces an image on
paper which is invisible when taken from the camera;
but by washing it over with a liquid containing gallic
acid the picture is gradually developed. In this
respect the calotype resembles the daguerreotype.
The following is an outline of Mr. Talbot’s process,
as improved by Mr. Oundell :—
To produce a calotype picture there are five distinct
processes, all of which, except the third, must be
performed by the light of a lamp or candle, sur-
rounded by a yellow glass, or in a room where the
light is admitted entirely through yellow glass, or
several thicknesses of yellow calico. These processes
are by no means difiicult; they require only care and
attention.
The paper must be compact and uniform in texture,
smooth and transparent, and of not less than medium
thickness. Afine post paper is manufactured for the
purpose, by “R. Turner, Ohafford Mill.” A half-
sheet having been selected, its surface is to be coated
uniformly with iodide of silver. This is done either
by the mutual decomposition in the substance of the
paper, of nitrate of silver and iodide of potassium, or
else by making use of the double iodide of silver. In
the one case, the paper is first prepared on one side
with a solution of nitrate of silver, made by dis-
solving 20 grains in an ounce of distilled water, and
allowing it to dry in the dark. It is next brought
into contact with a solution of iodide of potassium,
in which case the iodine goes to the silver, and
the nitric acid to the potash. This is best accom-
plished by pouring the solution of iodide of potas-
sium (1 ounce of the salt to a pint of water)
in a flat dish, to the depth of about @- inch. The
prepared side of the paper, previously marked, is
then placed in contact with the surface of the
solution, and holding the paper by an upturned
margin, it is to be gently drawn along the sur-
face, until the lower face is thoroughly wet. This
part of the operation ought not to occupy more than
a minute, as the compound formed on the paper is
easily redissolved. After draining for a short time,
the paper is placed on a clean surface, with the wet
side uppermost, until about half dry. If properly
conducted, the paper is completely coated with iodide
of silver, which must be retained uninjured. The
398
PHGTOGRAPHY.
paper is also saturated with nitrate of potash- and
iodide of potassium, which must be completely re-
moved. For this purpose the paper must be taken
byv its upturned margin, and floated on the surface of
a dish of clean water, where it-is to be left for 5 or
10 minutes, drawing it gently. now and then along. the
surface; the salts, being soluble, will separate com-
pletely, and the solution thus formed will-subside. If
the paper be taken up, and if a drop from its surface
allowed to fall into a solution of nitrate of silver
produce no precipitate; the washing is complete; if
a precipitate be produced, the paper must be left on
the water‘ some-‘time longer. It should be dried,
hanging up in‘ the air-by pinning one of the corners
to a- string, While wet its" surface must not be
touched. When ‘dry it may be‘ smoothed by pressure.
This iodized paper is now ready for use; but it may
be kept for a long time.
The second method of preparing iodized paper‘is
the simpler of the two. About 20 grains of nitrate
of silver are to ‘be dissolved in about 1 ounce of
distilled water, to which must be added 20 grains of
iodide of potassium in 1 oz. of water. A precipitate
of yellow iodide of silver is formed and is left to
subside, when the'clear liquid is decanted off, and the
precipitate washed two - or three times with warm
distilled water, settling and- draining between the
washings. The iodide of silver thus freed from nitrate
of potash and other impurity, has next poured over ‘it
enough water to make 1 ‘fluid ounce, the whole being
stirred up with a glass rod. Crystals of iodide .of potas-
sium-are next added,'one crystal at a‘ time, each to be
dissolvedubefore' another is put in. The solution
gradually becomes clear and then bright, forming the
double iodide of silver. This is best applied to the
paper by :means of‘the-gl‘ass rod, as already noticed,
and when dry, or nearly so, the paper is put into
water which must be changed five or six times in
about half 3.11l10U1‘,‘01“1111l)il the surface of'thepaper
is of a lemon yellow'colour, and a drop of the liquid
from its surface-does not produce a precipitate in'a
solution of nitrat'erof- silver. It may then be hung up
to dry, and when ‘dry, be" smoothed by pressure. In
this proce'ss‘the iodide of silver, being soluble in'ia
strong solution of= iodide of potassium, formsthe/ double
iodide, which‘ being decomposed on the addition of
water,-forms a precipitate’ of iodide of silver. "in the
substance of the paper, while the iodide‘ of potassium
is dissolved out by the water.‘ The iodized paper, if
properly‘preparedriby either of ‘the above-processes,
is not lsensitive'toi'light. ‘ - '
“The-nent process-'~ is "that of ‘exciting, or preparing,’
titer-paper ‘for the ‘camera. For-'thisipurpos'eitwo
solutions areu'equ‘ired, viz‘; a/ saturated solution rof
crystallized *galli‘c'lae'rd in cold distilledtvater, and‘ solution-1iof'rnitrateiot silver, '50’ ‘grains :to the ounce
of wat'ejrgitti whichu‘s added'i'l-é'ldraehmv of :‘glacial
acetic acid-2 ' use thelliisolntions ‘of gallicE acid; 41* 'orr5
giiain‘sfi ‘ofilt‘he =. crystals hare’; dissolved'1 in 5 a sphialr 'iwith
1'. lOZ 051iWitter»iiiTheifiphialiiisi t'o” . be shaken ,"i and :the
cdn'tentsipasseditliroughiarfilter1‘; ithe-"cle'a'r liquidi'zw'il'l
bei a s‘atura'tediE solution; andisitnwilliiinot1beconie

fmouldy so soon if the bottle containing it be placed
for a few minutes in boiling water.
fsolutions to the iodized paper, 3 drops of each are to
be added to 2 drachms of water; and the gallo-nitrate
of silver thus formed is to be spread over a clean
‘surface of plate-glass.
In applying these
The iodized paper is to be
brought down upon the liquid on the glass, and when
properly wetted, which is known by its ceasing to
curl up, it must be removed, and the excess of gallo-
nitratel-absorbed by placing over it a sheet of white
blotting-paper. After this it may be placed, while
damp‘, between the plate glasses of the camera frame
ready for use. If well prepared, it may be kept for
24 hours=without losing its whiteness or sensibility.
If 'the paper be required to be more sensitive, as
for portraits, the gallo-nitrate must be diluted with
less’wat'eiii-ail'enwi drciip'difihj‘Sfiiiiti? ; bht‘suclfca'se
the’io'peration miiht biz quickly-and;iskilfhlly performed,
as the gallo-nitrate decomposes in‘fia veisy few minutes.
The amount of dilution must depe’iid upon the bright—
ness 30f the day,-"-.the"brilliancy'of‘ithe“ object, and the
judgment and eiiperie’nce‘ ofthe‘io‘perator. Indee‘d,
much of thesii'cties’s‘oi' this ‘art ‘depeiids‘upon the two
last-named qualities.
The paper thus prepared is now ready for receiving
the object: the time of exposure may vary from a few
seconds to eight or ten minutes. When the paper is
removed from the-camera-slide, little or no trace of the
picture is to be seen‘; but it may be brought out by
the solutions of gallic‘ acid and aceto-nitrate of silver,
mixed in equal proportions, such as half a drachm of
each with half a drachm of distilled water. This mix-
ture must be applied to the surface of the paper by
any one of the methods already noticed, the whole
surface being thoroughly wetted. Then, on placing it
face upwards upon a plate of" glass, the picture will
gradually develop itself. During this operation, the
surface must be kept wet with the mixture of gallic-
acid and aceto-nitrate' of silver, or the light parts of
the picture will sink and become opaque. A gentle
application of heat, by holding the paper over the
steam of ' hot water contained in a ideepish dish, will
sometimes‘ assist the bringing‘ out 'of the picture.
Should theipicture begin to stain, and form dark
waves,‘-the excess of gallo-nitrate must be removed
by ‘placing the picture ‘on blotting-paper on a glass
plate, and moving a glassrod ‘quickly from one end of
the picture td-the other. Some of the‘ solution of
gallic—acidlalo'ne is to=benext>poured over the picture,
to complet'eithe' development.
The ‘nentoperation~ is ' fizrz'rzyPtlre picture, or photo-
graph‘, I'tlmsdeveloped; The excess of nitrate of silver
and oli=yellow iodide-must first‘ibe‘ removed; for which
purpose"the-5'p'hotdgrap'h is ‘to bev'placed 3face‘ down-
wards in“>‘water, and! gently moved ‘about; but the
water-"m'u’stiib'e’i changed 3 01*‘4: times in 8 cry-10
ininiitesiif'fdlllfe photograph is then to be‘presse‘d 1be‘-
tween 'fold'si- ‘05? white *bl'ottingpaperf 'f' The?’ remaining
nitrate 'lian'di io did’el- ‘of’ 5 silver’ ‘ may‘ be dissolved out? ‘by
placingith‘e photograph ini'a warm andfstrongisolution
o'f h'y‘posu'lpliite'l‘ offsoda "(41 "oz. ‘ tor the’ ‘p int ‘off water);
and iwhenntheiyellowl‘colouraof: the iodide‘ihasrdisap?
PHOTO GB-APHY.
399
peared, it must be washed in a considerable quantity
of water; and, to insure the getting rid of the last
portions of hyposulphite of silver, the photograph
may be left for a few hours in water, and then dried
between blotting-paper. The fixing is now complete;
but the photograph produced by this long series of
operations is 7265/6652'21‘6, and in order toobtain impres-
sions from it, in which the lights and shades are as in
nature, anotherprocess is required, viz. printing.
To prepare for printing, the negative photograph is
to be laid on a glass plate, and burnished with a steel
or agate burnisher until the surface is equallyr polished
and smooth.- This gets rid of the woolly appearance
caused by numerous projecting fibres raised during
the repeated washings : the paper becomes more per-
vious to light, and allows of closer contact with the
prepared paper which is to receive the positive im-
pression. The light parts of the negative may also be
made more transparent by scraping a little white wax
over them, placing thereon a sheet or two of blotting-
paper, and then passing. a hot iron a few times over
the latter. The sheet of paper for receiving the posi-
tive impression-is prepared with muriate of baryta
and nitrate of silver, as already described: the paper
should be quite flat and- smooth, and the negative
photograph laid upon it face downwards; a morsel of
wafer is then to be placed ‘between them at one of
the corners: they are then put into the reversing
frame, and exposed to light. . The fixing is toibe per-
formed as already described. The finished photograph
is best preserved by a thin coatingof gelatine, or it
may be mounted in a glazed frame.
Sir John Herschel has lately communicated to the
Ai/temezim a method of taking, photographic land-
scapes on paper, as practised by his brother-in~law,
Mr. John Stewart, resident at ‘Pan. This gentleman
is stated to have been singularly successful in his
application of the art to the depiction of natural
scenery, such as the superb combinations of rock,
mountain, forest, .and water, which abound in the
picturesque region of the Pyrenees. These photo‘
graphs are exquisite in their finish, and artistic in
their general-effect. “The-extreme simplicity of the
process employed by~him for the preparationof the
paper, its uniformity, and the certainty attained ‘in
the production of its results, seem- to'render. it well
worthy of being generally known to travellers:- It
need hardlybe mentioned ‘that the-‘air-pump’ em-
ployed may be one of so simple a construction as to
add very little to either the weight,-bulk, or expense
of the apparatus required for the practice of this art.
The obtaining of -a very perfect vacuum, for the imbibi~
tion of the paper, being a matter of little moment,—
a single barrel. (‘worked by a cross handle by direct
pull and push), furnished with a‘fiexible connecting-
pipe, and constructed so as to .be capable of being
clamped on theledge of I a table,=would satisfy every
condition.” -
The following observations. are confined to negative
paper processes, divisible int-o two;—the wet and the
The solutions employed for both these processes
are identical, and are'asfollows '. . .- . . _

Solution of iodide of potassium-of ‘the strengthof.
5 parts of iodide‘ to 100 of pure water.
Solution of .aceto-nitrate of silver, .in-the following
proportions : 15 parts of nitrate of silver; 20 of
glacial acetic acid; 150 of distilled water.
Solution of gallic acid, for-developing ;——a.-satu.rated
solution.
Solution of hyposulphite of soda; of the strength
of one part hyposulphite of soda to from 6 to 8 parts
water.
The solutions employed are thus reduced'to their-
simplest possible expression.
For both the wet and the dry processes the paper
is iodized as follows :—-In a tray containing the above
solution, plunge, one by one, as many sheets of paper
(twenty, thirty, fifty, 850.) as are likely to be required
for some time. This is done in two or three minutes.
Then roll up loosely the whole bundle of sheets,
while in the bath; and picking up the roll by the
ends, drop it into ‘a cylindrical glass vessel with a foot
to it, and pour the solution therein, enough to cover
the roll completely (in case it should‘ float up above
the surface of the solution, a little piece of glass may
be pushed down to rest across the roll'of ‘paper and
prevent its rising). The vessel with the ‘roll of paper
is placed. under the receiver ‘of an air-pump and the
air exhausted; this is accomplished in a very few’
minutes, and the paper may then be left five or six
minutes in the vacuum; Should the glass be too
high (the paper being in large sheets) to .be inserted
under a pneumatic pump receiver, a stiif lid lined-
with India-rubber, with a ‘valve in the centre ‘com-
municating' by a' tube with -a- common direct~action
air-pump, may be employed with equal success. After
the paper is thus soaked iii .vaczio it is removed, and-
the roll droppedback into the tray with the solution,
andthen sheet by ‘sheetpicked off and hung up to?
dry, when, as with all other iodized paper, it will
keep' for an indefinite time. By the action of the
air-pump the paper isthoroughly iodized, and with an
equality throughout- that no .amount of ordinary
soalring‘procures. . The operation. is accomplished in
a quarterxof an hour, which otherwise generally. em—s.
ploys one, two, or more hours. Another ~advantage
is, that this paper is never solarized/ even in the
brightest sun; and it will ‘bear whatever amount of;
exposureris necessary for the ;deepestvand most inr--_v
penetrable shadows in the view, without injury :to'
the bright lights. '
Wei ;Process. ~—ZE[av~ing prepared the above solu-:
tion of- aceto-nitrate of silver,~float -a ‘sheet of the
iodized paper: upon the-surface of this sensitive bath,
lcavingit there for about ten' minutes. During this
interval, having placed ‘the glass or slate 'of your
slider quite: level, dip a .sheet- of thick clean white
printing (unsizedypaper ‘in water, and lay it on the
glass or-slateas a wet lining to receive the sensitive
sheet. - Amexpert manipulator may then, removing
the sensitive sheet‘ from the bath, extend it (sensitive
side ;uppermost). on this wet paper lining, without
allowing any-air globules .to intervene.-
But it is‘
‘dificult ; and a very simple and most edectual mode of,
400
PHOTOGRAPHY.
avoiding air globules, particularly in handling very
large sheets, is as follows. Pour a thin layer of
water (just suflicient not to flow over the sides) upon
the lining paper, after having extended it on the
glass or slate, and then lay down the sensitive paper
gently and by degrees, and floating, as it were, on
this layer of water; and when extended, taking the
glass and papers between the finger and thumb, by an
upper corner, to prevent their slipping, tilt it gently
to allow the interposed water to flow off by the
bottom, which will leave the two sheets of paper
adhering perfectly and closely, without the slightest
chance of air-bubbles ;——it may then be left for a
minute or two, standingupright in the same position,
to allow. every drop of water to escape; so that when
laid flat again, or ‘placed in the slider, none may
return back and stain the paper. Of course, the
sensitive side of the sheet is thus left exposed to the
uninterrupted action of the lens, no protecting plate
of glass being interposed,—-and even in the dry and
warm climate of Pan, the humidity and the attendant
sensitiveness are fully preserved for a couple of hours.
To develop views thus taken, the ordinary sa-
turated solution of gallic acid is employed, never
requiring the addition of nitrate of silver; thus pre-
serving the perfect purity and varied modulation of
the tints. The fixing is accomplished as usual with
hyposulphite of soda, and'the negative finally waxed.
Dry Proeess.--In preparing sheets for use, when
dry, for travelling, &c., paper previously warned is not
used, and thus [a troublesome operation is got rid of.
Taking a sheet of 'iodized paper, in place of floating it
(as for ‘the wetprocess) on the sensitive bath, it is
plunged fairly into the bath, where it is left to soak
for five or six minutes; then removing it, wash it for
about twenty minutes in a bath, or even two, of dis-
tilled water, to remove the excess of nitrate of silver,
and then hang it up to dry, instead of drying it with
blotting paper. Paper thus prepared possesses a
greater degree of sensitiveness than waxed paper, and
preserves its sensitiveness, not so long as waxed
paper, but sufficiently long for all practical purposes—-
say ‘thirty hours, and even more. The English manu-
factured paper is far superior for this purpose to the
French. To develop these views, a few drops of the
solution of nitrate of silver are required in the gallic-
acid .bath. They are then finally fixed and waxed as
usual. ‘
These processes appear to be reduced to nearly as
great a degree of simplicity as possible: stains or
spots do not‘occur, and there is a regularity and cer-
tainty in the results that are very satisfactory. The
aerial perspective and gradation of tints are admirably
preserved; and the deepest shadows are penetrated
and developed—speaking, in fact, as they do to the eye
itself in- nature. ’ In exposing for landscape, all con-
sideration of the bright lights is neglected, the time
being limited with reference entirely to the dark and
feebly-lighted parts of the view : with a iii—inch lens,
the time .of exposure has thus varied from ten minutes
to an hour and a half, and the action appears never to
have ceased.

The influence of the air-pump in this respect ap-
pears to be very sensible, and deserving of further
examination and extension. Mr. Stewart purposes,
not only to iodize, but to render the paper sensitive,
with the action of the air-pump, by perhaps suspend-
ing the sheet, after immersion in the nitrate bath,
under the receiver of the air-pump for a few minutes,
before exposure 'in the camera, or by some other
manoeuvre having the same object in view. He has
‘chiefly employed Canson’s French paper in iodizing
with the aid of the pump. Few of the English manu-
factured papers are sufiiciently tenacious in their
sizing to resist the action of the pump, but they may
easily be made so; and were, ‘in short, the English
paper so far superior in quality to the French, only
better sized, that is, with glue less easily soluble, even
though more impure, there is scarcely any limit to the
beauty of the views that might be produced.
A very decided advance in the art of photography
has been made by the use of OoLLonIou (gun cotton
dissolved in ether—see GUN COTTON) in a film upon
glass as the surface for receiving the picture. The
following instructions by Mr. Philip H. De La Motte
are for a negative.l
Thin plate glass is used of the size of the frame,
and this must‘ be cleaned by washing it in water con-
taining a small quantity of nitric acid, or water con-
taining a small quantity of ammonia and tripoli mixed.
The glass must then be well washed or rinsed in clean
water, wiped dry, and polished with a clean leather.
To coat t/ze Plate with Collodz'om—Hold the glass
by one corner, or, if large, place it in a frame,2 and
pour on the collodion, which will readily difl'use itself
all over. Immediately pour the liquid 05 again into
the bottle from one corner, and by bringing the hand
which holds the glass plate down a little, .the liquid
will run to the edge; and, by drawing the mouth of
the bottle along the edge of the plate, the collodion
will run into an even surface. Very little practice will
soon enable the operator to obtain a most perfect
coating.
The plate is now ready for the bath. Take nitrate
of silver 33 grains to the‘ ounce of distilled water,
and filter. it. The dipper must be raised out of the
bath, and the plate gently lodged upon the edge at the
end. The plate must then be immersed in the bath,
letting it remain there for half a minute.‘ By raising
it out gently it will be seen that the surface will have
a greasy appearance, and the time for removing it out
of the bath to the slide for the camera, will be known
as soon as the greasy appearance disappears from the
plate. It is well to raise the plate two or three times
from the bath, that the ether may evaporate. The
plate should in this wet state be placed in the slide,
and put into the'camera.
The time of exposure must entirely depend upon
the light upon the object about to be taken, and the

(1) We may also refer to a pamphlet entitled “ Directions for
obtaining both Positive and Negative Pictures upon Glass by means
of the Collodion Process, 850., by T. H. Henna .” This work also
contains Gustave 1e Gray’s method of obtaining black and violet
colours in the positive proofs by the use of chloride of gold.
(2) The frames are manufactured by Messrs. Home 8: Co.
PHOTOGRAPHY.
4101
size of the diaphragm used, with the lens: for views
or portraits,.from one to ten seconds, and in dull
weather from one minute to a minute and a half.
After exposing the plate in the camera, it must be
taken from the slide and placed, collodion side up-
wards, upon a levelling stand.
To elevelop the .Pietura—Pyrogallic acid 3 grains,
glacial acetic acid 1 drachm, distilled water 1 ounce.
Take a sufficient quantity of the above solution, pour
it quickly over the plate, frequently moving the solu-
tion by blowing gently upon the plate. A few drops
of the nitrate of silver solution from the bath, added
to the developing solution, just before applying it to
the plate, in dull or cold weather, will greatly assist
the bringing out of the picture. A little practice will
soon show how long each subject will require; after
this pour on the plate a gentle stream of water; then
add a saturated solution of hyposulphite of soda,
which will, in a few seconds, dissolve the undecom-
posed iodide, and fix the picture; then allow a stream
of water to flow all over the plate, so as to entirely
get rid of the hyposulphite of soda; the picture is
then finished. By applying a gentle heat to the plate,
it will soon dry, when it will be fit for varnishing;
the picture is then ready for printing from in the
ordinary way.
ALBUMEN has also been used both on glass and
paper with very considerable success. The following
instructions for albuminising glass are by Messrs.
Ross and Thomson of Edinburgh:—
The white of eggs, having 12 drops of saturated
iodide of potassium added to each egg, is beaten up into
a large mass of froth, and allowed to stand for 10 or
12 hours, till it falls into a liquid; the albumen is then
poured plentifully over the surface, which must be
very clean; and when all is covered, the glass is turned
gently over, and made to revolve at a moderate rate
before a clear fire (being suspended by worsted thread
and a bent brass wire, which catches the opposite
corners of the glass), until it begins to crack at the
edges; these cracks will soon spread over the whole ;
it will keep any time in this state, or it may be used
as soon as cool. Before being piit in the camera it
is dipped into nitrate of silver, 70 grains to the ounce
of water, having a twentieth apart of strong acetic acid
mixed with it; immediately after being dipped in this
it is washed in water once or twice; the picture can
be taken on it now, or 6 or 8 hours after; 3 or 41
minutes will suffice for light objects; red or green
will of course take longer. It is developed by pouring
a saturated solution of gallic acid upon the prepared
side, and spreading it with a piece of cotton wool ;
the picture then appears slowly, of a reddish colour.
When brought up as far as it will come, a little of the
silver solution is mixed with gallic acid, and spread
over it with apiece of clean cotton; the picture then
assumes a darker and more vivid appearance, when
it is fixed by means of hyposulphite of soda, and
this, when washed off, finishes the negative.
1/Ve now proceed to notice the practice of the art
upon metal.
Dxeunnnnorrrn pictures are taken on the surface
VOL. II.

of plated copper plates, which are now manufactured
at Shellield for the purpose, and when out to the
required size, are planished with the hammer, and
polished at the lathe. In order to produce a per-
manent picture on one of these plates, six distinct
operations are required.
1. Cleaning the silvei'erl plate, so as to obtain a
perfectly pure and polished surface—The materials
required are, calcined tripoli in an inpalpable powder,
kept in a box with a piece of fine muslin tied over it;
lamphlaeh, calcined in a crucible till it ceases {to
smoke, then reduced to fine powder in a “glass or
porcelain mortar, and kept for use like the tripoli ;
rouge, the finest washed, preserved in the same man-
ner ; and, lastly, olive oil. The cleaning is best per-
formed at a lathe, with circular buffs covered with
unbleached cotton velvet. The buff N o. l is prepared
with olive oil and tripoli; No. 2 with tripoli alone;
and No. 3 with lampblack and a little rouge, or with
lampblack alone. The plate is mounted in a holder,
and pressed against the
buff No. 1, which quickly
removes any former pic-
ture, scratches, or tar-
nish. The plate is then
lightly wiped with cotton
wool, to remove the su-
perfluous oil, 850.; and
the No. 2 buff is used
until all the oil is got
rid of, and the plate ap-
pears to be equally po—
lished. The plate is next placed, with the silver side
upwards, on a stand, Fig. 1610, and the flame of a
spirit-lamp applied to the under surface, until a slight
smoke rises from the plate and it assumes a whitish
tint: this gets rid of every trace of oil, and the plate
then receives its final polish from the buff N0. 3. .
Should a lathe not be procurable, the polishing by
hand is performed by a number of cotton-velvet buffs,
varying in size with that of the plates. The first buff
is prepared with tripoli and oil, the second and third
with tripoli alone, and the fourth with prepared lamp-
black and a very little rouge. The plate is put face
downwards upon the buff No. 1, and then, by means of
a plate-holder, Fig. 1611, made adhesive with prepared
India-rubber, the plate is moved briskly over the
surface of the buff, with a slight pressure, for a minute
or two; it is then cleared from oil, &c., with cotton
wool, and rubbed lightly on the buff No. 2; then on
No.3 with fresh dry tripoli; next heated with a spirit—
lamp, and finished on
the buff No. 4:. The
buffs should be kept in
separate wooden cases,
and be quite dry at the
time of using. The
plates, after being po-
lished, should be kept




Fig. 1611.
’ free from contact, in a vertical position, in a box, Fig.
1612, furnished with grooves; and when a plate is
about to be used, it should receive a final polish, and
D n
4-02
rnoroenxrnr.
have its grain laid in a particular direction by means
of a buff, Fig. 1613,
covered with cotton vel-
vet or soft doe-skin.
The plate should be
briskly rubbed for a few
seconds, until all the
fine lines on its surface
appear in one uniform
direction. For portraits,
these lines should be


o
a, .g‘l'
I! ll
r
i
D
p
I
l
snug.‘



1613.
Fig. 1612.
across the direction of the face, and for landscapes,
in the direction of the view.
Some persons prefer to deposit on the silver surface
a coating of pure silver, by means of voltaic electricity
[see ELncrno-METALLURGY], which is polished and
prepared for the second operation, now to be de-
scribed.
2. Applying flze sensitive coating—The sensitive
coating is prepared by means of vapour of iodine and
an accelerating material, such as chloride of bromine.
The latter is prepared by mixing 1 oz. of a saturated
solution of bromine with 1 drachm of strong hydro-
chloric acid.1 The bromine apparatus, used for hold-
ing the plate during the application of the coating, is
represented in Fig. 16141. It consists of two deep
glass pans, contained in a wooden box, at the back of



which are two openings, covered with white paper,
one opening for each pan. In front of the box, oppo-
site the back openings, are two other openings with
flaps opening outwards, and each flap is lined with
looking-glass. The apparatus has also two glass covers,
and a series of wooden frames sliding over them. In
one of the pans is put half an ounce or an ounce of
pure iodine in crystals, and in the other pan water to
the depth of about half an inch, with a quantity of
the chloride of bromine sulficient to bring the solution
to the colour of pale sherry. The pans are then closed
with their covers, and the apparatus placed before a
window in a moderate light. The silver plate is next
placed in its frame at the top of the apparatus over
the iodine, and the glass cover removed, so as to
expose the plate to the action of the vapour. The
small mirror is then adjusted to such an angle that,

(1) There are many other preparations of bromine, known as
can bromée, bromide of iodine, Hungarian solution, Woolcott’s
American accelerator, bromide of lime, 8w.

by looking into it, the white paper at the back is
seen reflected from the surface of the silver plate, and
thus any change of colour may be instantly detected.
When the surface is of a light straw-colour, the cover
is put over the iodine, and the slide holding the silver
plate shifted over the pan containing the chloride of
bromine, the cover of which is withdrawn, the mirror
adjusted, and the glass cover removed so as to expose
the plate to the vapour. When it has attained a deep
yellow colour, it is again brought over the iodine;
and when it has acquired a rose tint, it is to be placed
in the camera frame. Should the plate be left too
long over the iodine in the first coating, and the rose
tint begin to appear, it must be brought to a full rose
over the accelerator, and then to a blue over the
iodine. If this fail to produce a good result, the plate
must be repolished.
3. Ezposure in fire camerm—Thc camera being
mounted on a firm support, the focus is carefully
adjusted until a perfectly distinct image of the object
is seen on the ground-glass plate, which occupies
exactly the position in which the silver plate is to be
placed ; the light is then shut off by a brass cap, the
plate introduced, the cap removed, and the plate
exposed to the light. The time required for making
the impression may vary from 1 to 60 seconds, de~
pending to a great degree upon the season of the year,
the time of the day, and the brightness or clearness of
the atmosphere. When, according to the judgment
of the operator, sufficient time has been allowed, the
light is shut off, and the camera removed to a dark
room, in order to bring out the picture, at present
invisible, by exposure to the fumes of mercury.
41. Mereurz'alz'zz'ng t/ze plate—The mercury box, Fig.
1615, is of wood, with an iron cup in the bottom for
holding the mercury, which is heated by a spirit-lam p.
The upper part
of the box is
furnished with
grooves for re-
ceiving the same
sliding frame as
was used for the plate in the ca- 3
mera. In front
of the box is a
small window of
yellow glass, fur-
nished with a sliding shutter. From 4 to 6 oz. of
pure mercury are put into the cup, and this is heated
until the outside of the cup begins to be too hot to be
conveniently touched; the plate may then be put in
its place in the mercury box, and the development of
the image can be watched by holding a piece of lighted
paper at the‘ side, or by looking through the yellow
glass in front. If the operation be conducted slowly,
a clearer and sharper outline will be produced than if
done quickly; the time, however, may vary from 5
to 20 minutes. The box should be kept at a tem-
perature of about 90°. The mercury must be kept
pure and clean, and be returned to its bottle after the
operation. ‘


PHOTOGRAPHY.
$03
5. Removing the sensitive coating—When the pic-
ture has been distinctly brought out, the plate is
removed from the mercury box and dipped quickly
into a solution of hyposulphite of soda (2 oz. to the
pint). The colour will gradually disappear: the plate
is then to be put into a vessel of filtered water, to re-
move the excess of hyposulphite, after which a little
pure water is to be poured over the surface of the plate.
6. Fixing the picim'e is performed with a solution
of gold, prepared by dissolving 15 grains of chloride
of gold in a pint of water, and gradually adding it
to a mixture of 60 grains hyposulphite of soda and
8 oz. of water, the whole being well stirred after each
addition. The solution will be at first slightly yellow,
but will become perfectly limpid. The solution is to
be poured over the plate, so as to cover it entirely,
and the flame of a large spirit-lamp applied to the
back, moving the plate about over the flame: the
picture will brighten, and in a minute or two come
out bold and distinct. This effect being produced,
the liquid is to be thrown off, and the plate dipped
into water, washed and dried. A large plate may be
dried by placing it on a smooth piece of copper, and
pouring some boiling distilled water over its surface,
inclining the plate so that the water may run off from
one of the corners, and it will very soon become
quite dry : or the plate maybe dried by placing it on
the fixing stand, made horizontal by levelling screws,
and applying the flame of a spirit-lamp below it. Or
the plate may be held by pliers at one corner, some
filtered distilled water poured over it; then inclining
the plate, the water will flow to the side, and may be
removed by touching it with blotting paper; the
spirit-lamp is then to be applied to the upper corner,
and the flame gradually brought down. The forma-
tion of spots may be to a great extent prevented by
blowing gently downwards on the plate. Care must
be taken not to overheat the plate, or some of the
silver will become detached. The lamp must be in-
stantly removed when small bubbles of air form on
the surface of the metal.
Some attempts have been made to improve daguerre-
otypes by the application of colour. The colours are
dry, ground extremely fine with dry gum or starch,
and dusted on with a fine camel’s-hair pencil, a very
small quantity of colour being taken up at one time,
and blowing off the superfluous colour with an elastic
bottle of caoutchouc; when the proper tint is pro-
duced, it is fixed by breathing on the plate. Or the
colour mixed with spirit of wine may be applied with
a hair pencil, and dry colour applied over it. Car-
mine, chrome-yellow, ultramarine, and their combina-
tions, are best adapted to this purpose. In the
application of colour to a daguerreotype, or “ in
visibly uniting art and science on the same plate, the
operator should he possessed of knowledge and
feeling sufficient to know the proportions in which
art and science should intermingle, so as to be sub-
servient to each other.”
Whether photographic pictures will ever be pro-
duced in their natural colours, is a question which
cannot yet be determined. The circumstance that

the rays by which photographic pictures are produced,
are Jar/i rays, distinct from the colorific rays, would
appear to be unfavourable to such a result. It
appears, however, that Sir John Herschel has suc-
ceeded in obtaining coloured pictures of the prismatic
spectrum in light colours on a dark ground; he is
“not prepared to say that this will prove an available
process for coloured photographs, though it brings the
hope nearer.”
The circumstance that the focus of the colorific rays
is not the same as that of the photographic or chemical
rays, is a difficulty in the way of the photographer.
In setting his camera, he may obtain a perfect optical
image by means of the luminous rays which he can see,
but this image will not correspond with that formed
by the chemical rays which he cannot see. In order to
produce a picture_in focus, the object-glass must be
moved through a space equal to the distance between
the foci of the colorific and the photogenic rays. In
order to enable the photographer to make this adjust-
ment, instruments named focimeiezs have been con-
structed. In one by M. Claudet, there is placed
before the camera at the same instant, a circular
arrangement of cards formed into segments, each
segment being at a different distance from the lens.
A photographic picture of all these segments is at
once produced, and the picture of one of them will
be found to be more distinct than all the others ; con-
sequently, the plate or paper is in the photogenic
focus which corresponds with that one. Mr. G. Knight
determines the photogenic focus by placing the pho-
tographic plate or paper in an inclined groove, so
that different parts of it are at different distances
from the lens; aprinted sheet is then placed before
the camera, and in the resulting picture, some parts
of the print will be much more distinct than others,
and thus that point of the plate, or of the inclined
groove, which corresponds with the photogenic focus,
is determined. -_
A remarkable method of obtaining pictures by the
agency of light, was discovered some years ago by
M. Moser, of Konigsberg. He has established the fact
that light constantly emanates from all bodies, even
in complete darkness; and that when two bodies are
placed near each other, the one impresses upon the
other a picture of itself. In this way, true photogra-
phic pictures are formed, engravings copied, &c.; but
they are invisible, and continue to be so until developed
by the action of certain vapours, such as vapour of
water, mercury, iodine, &c. If a sovereign be placed
on a piece of ground glass on a warm mantelshelf,
and be left for half-an-hour, a beautiful image may be
developed, by simply exposing the glass to vapour of’
mercury.
Such is a brief outline of the delicate and beauti-
ful art of photography. The processes are subject to
considerable variation in the hands of different pro-
fessors and scientific men; these the amateur will
find detailed in treatises devoted to the subject, and
will be able by experience to decide upon the methods
best adapted to his means and manipulative 'skill.
The art of photography received abundant illustra~
n n 2
41041
PHOTOGRAPHY.
tion in the Great Exhibition, but rather as a fine art
than a useful art. There were portraits, views and
landscapes in abundance, but no specimens of copies
of ancient inscriptions; no delineations of natural
objects, with the view to illustrate natural history;
no enlarged representations of the microscopic pro-
ducts of nature, or of the dissected parts of plants
and animals; scarcely an attempt to show the action
of the actinic spectrum on chemical preparations, or
on natural colours ; no impressions of the lines in the
photographic‘, corresponding to those in the luminous
spectrum; no copies of pages of ancient manuscripts;
no miniatures of printed books, &c. It is well re-
marked in the Jury Report, that “ photography holds
a place at present intermediate between an art and a
science, a position eminently favourable to develop-
ment in either direction. Its pursuit as an elegant
and most extensively useful art, affords a strong mo-
tive for inquiry and experiment in the improvement
of its processes; in the course of which, an infinity
of facts, new and unexpected, come forward, every
one of which may turn out to be the embodiment of
some pregnant scientific principle; nay, even the
smallest minutiae of manipulation, on which it is
found that ‘success or failure in the production of
artistic effect depends, may, if duly observed and
reasoned on, afford indications, linking together the
known and the unknown in optical science, and tend-
ing’ to bring these mysteriousv operations of light
within the pale of exact reasoning. On the other
hand, science is too much in the habit of repaying to
art, with interest, ever-y assistance of that nature, to
leave room for doubt of similar results in this in-
stance, when once the principles of operative che-
mistry shall have assumed a definite form and sub-
jective connexion. It is this which affords us full
assurance that photography is yet in its infancy, and
that all which has been hitherto accomplished—
marvellous vand exquisite though it be—~—is as nothing
to what will 'be performed when the veil shall be
removed, which, for the present, obscures its true
scientific principles.” The rapid advance of the art
during the brief period of its. existence, is well
illustrated by the fact, that the method formerly
adopted for procuring daguerreotype portraits re-
quired a person to sit without moving for 25 minutes,
in a glaring light, whereas, at the present day, the
effect is produced almost instantaneously.
The introduction of the accelerating process by
M. Olaudet, at once improved the practice of por-
trait-taking ; two daguerreotype establishments were
formed in London, and although the portraits taken
were deficient in expression andhad other defects,
yet the receipts at these establishments several times
amounted to £60 in one day. The use of Mr. Talbot’s
Oalotype process for portraits, by Mr. Oollen, was a
further improvement in this branch of the art; and
as the efl’ect of the picture could be heightened by
the brush, defects of expression could be removed,
and the likeness improved, at subsequent sittings.
During‘ a portion of the months of December 1852
and January 1853, the Society of Arts, London, held

an exhibition of photographs, collected from the most
distinguished artists and amateurs in this country,
and some from‘ continental artists. The specimens
exhibited exceeded 1,000 in number, and afforded a
very favourable idea of the condition of the art at the
time. On the 26th January, Mr. Glaisher read a
paper to the Society, “ On the chief Points of Ex-
cellence in the different Processes of Photography, as
illustrated by the present Exhibition.” The follow-
ing observations are abridged from the printed report
of this lecture. Of the various photographic pro-
cesses now in use the range of practice assigned to
the ealoz‘ype has been very general, with a leaning,
however, to outdoor and local scenery. That of the
wax-paper has been more strictly defined; and on the
Continent we find it employed in architectural designs,
and fragments of carved and massive ornamentation.
In England it has. been chiefly employed to perpetuate
the passing scene, with little ‘discrimination as to its
character. The albamz'm'seel glass has been applied to
general representation, such as views, landscapes and
groups of statuary. The albumz'vzz'seal paper has also
been employed upon groups of statuary. The col-
Zodz'on has furnished designs of various character,
including the whole of the portraiture in this exhibi—
tion. Some of the effects of the collodion process
are so admirable, and the points of failure in all so
much less exaggerated than those either of paper or
albuminised glass, that this appears to be the process
which ought to be specially cultivated: it generally
exhibits a natural interpretation of the lights and
shadows, which rarely fails to communicate a similar
effect to the subject. In fact, this process is less
eminent in failure, and more eminent in success, than
the other processes illustrated in the exhibition, for
it combines the‘ excellencies of our best photographs,
with fewer of their defects. .
The difliculties of representing woodland and forest
scenery were evident in this exhibition: the tree,
whether alone. and filling the central area of‘ the
picture, or one of several, is more imperfectly repre—
sented than any of the many creations of art and
industry. Very few of the trees are perfect in defini-
tion towards the top and outer branches, arising from
their continued stirring with the motion of the air.
In the same manner the gentle movements of the
leaves in summer tend to produce confused results.
A more sensitive medium than the paper is required,
upon which to obtain an instantaneous impression.-
This want may probably be supplied by the collodion,
or by Mr. Talbot’s instantaneous process.1
The representation of running water is a difficulty
‘that points also to a highly sensitive process, and an

(1) It appears from recent experiments, that the exposure of
the prepared surface to the optical image for an instant is sum-
cient to produce a perfect photographic picture. A printed paper
was attached to the face of a wheel, and this was made to rotate.
The camera with the prepared photographic surface was placed
opposite to the wheel and properly adjusted, and then the room
was darkened. The wheel was next illuminated for an instant by
a strong spark from the conductor of a powerful electric machine,
and this instantaneous appearance of the wheel before the camera
, was sufiicient to produce a perfect'picture.
PHOTO GRAPHY-e—PHOT'OME TRY.
405
instantaneous impression. In a water-mill on paper,
the water descending in a body from the trough above
the wheel gives the idea of a soft and rounded mass,
the apparent rotundity being conveyed by the shadow
which rounds the edge; the characteristics of water
as exhibited-under any circumstances are totally lost.
In short, quickly running and» ruffled water in the
present collection has not been in any case depicted
with satisfactory results.
Paper appears to be well applied to subjects of
no great finish and delicacy, and its general tone
is to be preferred to that of wax—paper. The latter
is most frequently recognisable by great strength of
tone and by the prevalence of a citrine hue, which is
very objectionable in excess. This process seems to
exceed the paper in the power of discriminating
material, and some of the finest specimens in the
collection are due to its employment.
The glass processes, either by albumen or collodion,
appear to be best fitted for conveying subjects of a
smooth and delicate nature. The specimens exhibited
showed the greatest finish and delicacy, and it is
thought that the collodion will supersede the albu-
minised glass.
Many of the photographs are wanting in 'verticality,
in consequence of not properly adjusting the visual
axis of the camera. The camera ought to. be furnished
with a spirit—level to secure horizontal adjustment in
the field with facility and certainty. In some cases
indifferent object-glasses appear to have been used,
and in some others, where the object-glass has been
good, it has been so ground as to give good definition
within very narrow limits.
“ Whether photography will ever exist as an inde-
pendent art, without assistance borrowed from the
artist, is a matter of pure speculation. At the pre-
sent time there is much to be done before this most
graphic process can approach within even near limits
to the beautiful semblances of nature which are
preserved in the works of our best artists. It is
necessary that the photographer should receive a
better artistic education; that he should be better
acquainted with those laws belonging to science by
which the canvass is made to assume the semblance
of some of nature’s most agreeable effects: it is
necessary that he know how to choose his point of
' view; to decide upon the proper balance of light-and
shade; to have a correct appreciation of the strength
of outline and development of parts belonging to the
distances of his picture; that he should not. resort to
violent contrasts for effect, and that he should choose
that tone most in accordance with his subject. The
true knowledge of these, among other things, must
belong to the photographer who would step beyond
the level of ordinary practice. To the artistic spirit
infused into the Photographic Society, so newly
organised, we must look for his better guidance in
reference to those points of study; but with all its
imperfections, photography may be considered as
sufficiently under control to be rendered a subsidiary
and highly useful art.” In the present collection there
are indications of its application to the microscope, and

to the medical profession in the portraits of persons
afflicted with mental disease; admirable copies of
engravings were also shown, and a few illustrations
of tropical ‘scenery.
In conclusion, we may just refer to the application
of Mr. Wheatstone’s beautiful instrument, the stereo-
scope, to photography ; to the attempt to transfer the
collodion picture from the glass to the wood en-
graver’s block; and to the success which has long
attended the use of sensitive paper in furnishing a
sort of perpetual register of meteorological and mag-
netic instruments.
PHOTOMETRY is the art of measuring the
relative intensities of different artificial lights. The
variations in the intensity of light cannot be measured
by an instrument in a manner similar to that by which
variations in temperature are measured by the ther-
mometer, or in the pressure of the atmosphere by the
barometer. Although the quantity of light which
fallsv upon the earth differs greatly at different times,
depending upon the height of the sun above the.
horizon, upon the presence or absence of clouds, and
the state of the atmosphere, yet we have no means of
comparing days together with respect to their light,
as we are accustomed to do as regards their heat.
We have no instrument or contrivance by which light
alone can be made to produce mechanical motion, so
as to mark a point on a scale, or to give a direct
‘reading off of its intensity or quantityqat any moment.
“This obliges us to refer all our estimations of the
degrees of brightness at once to our organs of vision,
and to judge of their amount by the impression they‘
produce immediately on our sense of sight. But the
eye, though sensible to an astonishing range of dif-
ferent degrees of illumination, is, partly on that very
account, but little capable of judging of their relative
strength, or even of recognising their identity, when
presented at intervals of time, especially at distant
intervals. In this manner the judgment of the eye
is as little to be depended on for a measure of light
as that of the band would be for the weight of a body
casually presented. This-uncertainty, too, is increased
by the nature of the organ itself, which is in a con-
stant state of fluctuation: the opening of the pupil,
which admits the light, being continually contracting
and expanding by the stimulus of the light itself, and
the sensibility of the nerves, which feel the impression
varying at every instant. Let any one call to mind
the: blinding and overpowering effect of a flash of
lightning in a dark night, compared with the sensation
an equally vivid flash produces in full day-light. In
the one case the eye ‘is painfully affected, and the
violent agitation into which the nerves of the retina
are thrown, is sensible for many seconds afterwards,
in a series of imaginary alternations of light and
darkness. By day, no such effect is produced, and we
trace the course of the flash, and the zig-zags of its
motion, with perfect distinctness and tranquillity, and
without any of those ideas of overpowering intensities
which previous and subsequent total darkness attach
to it. But yet more. When two unequally nated objects (surface of white paper, for instance)
406
PHOTO METRY.
are presented at once to the sight, though we pro-
nounce immediately on the existence of a difl'erence,
and see that one is brighter than the other, we are
quite unable to say what is the proportion between
them. Illuminate half a sheet of paper by the light
of one candle, and the other half by that of several,
the difference will be evident. But if ten different
persons are desired, from their appearance only, to
guess at the number of candles shining on each, the
probability is that no two will agree. Nay, even the
same person, at different times, will form difl'erent
judgments. This throws additional difficulty in the
way of photometrical estimations, and would seem to
render this one of the most delicate and diflicult
departments of optics.” 1 The eye is, however, able to
judge with tolerable accuracy of the equality of two
lights, or of two degrees of illumination seen at once.
Thus, in order to ascertain the relative quantities of
light furnished by two different lamps, place two
discs of white paper a few feet apart on a wall,
and throw the light of one lamp upon one disc, and
the light of the other lamp upon the other disc: if
the lamps are of unequal illuminating power, the
lamp which affords most light must be moved back
until the two discs are equally illuminated. Then on
measuring the distance between each lamp and the
disc which it illumines, the luminous intensities of
the two lamps may be calculated. As the intensity
of light from a point or luminous source diminishes
inversely with the square of the distance, [see
LIGHT. See also HEAT, Fig. 1135,] so the intensities
of the two lamps are to each other as the square of
the distance. If, when the discs are equally illumi-
nated, the distance from one lamp to its disc is double
the distance of the other lamp from its disc, then the
first lamp is 41 times more luminous than the second;
if the distance be triple, it is 9 times more luminous,
and so on.
In this experiment the eye cannot judge very accu-
rately as to the exact degree of equality in the light
thrown upon the two discs; but by means of two
conical tubes, Fig. 161.6, united at their smaller ex-


.p '_ If _.
l itgffl- .. I-
"l," .-'v
‘18
l
“W TK\'\\__<—\q;;\



Fig. 1616.
tremities, and terminating there in two discs of paper,
it is more easy to decide when the discs are equally
luminous. If, for example, it is desired to compare
the light of a candle with that of a lamp, in order to
ascertain how many candles will give a light equal to
_ that of the lamp, the two lights are placed so far
apart that their rays shall not interfere, the broad end
of one of the tubes being directed to the lamp, and

(1) Herschel, Evzcyclopcedz'a Metropolitana, article LIGHT.

that of the other tube to the candle. The lamp is
drawn back, or the candle moved forward, until the
two discs are equally luminous. The distances are
then measured as before.
A still better arrangement than the above was
contrived by Professor Ritchie, and is shown in
section, Fig. 1617. It consists of a rectangular box,
open at both ends, and blackened within to absorb




Fig. 1617.
extraneous light. At the top is a long narrow rect—
angular slit, A 13, covered with tissue or oiled paper.
Within are two pieces of looking-glass, c 1) and o n,
cut from the same piece, in order to secure uniformity
of reflection. Each mirror is of the width of the box,
and its reflecting surface is turned towards the open
end of the box. The upper edges of the mirrors meet
at 0, and the line of junction divides the space A B
into two equal parts: it is moreover covered with a
piece of black card, to prevent the mingling of the
lights reflected from the two mirrors. In using this
photometer, as it is called, it is placed between the
lights, the intensities of which are to be compared, so
that they may be reflected from o 1) and o n, upon
the tissue paper AB. The instrument is then brought
nearer to one or other of the two lights, until, to an
eye placed above AB, the two portions A c, B 0, ap-
pear to be equally illuminated, which may be judged
of with tolerable accuracy. The distances must be
measured from the vertical 0 F. In viewing the illu-
minated surface A B, the eye should be protected
from extraneous lights; for which purpose a prismatic
box is provided; it is about eight inches long, and
blackened within to absorb shining light. One end of
this box is to rest on the illuminated surface A B, and
the other is to be applied close to the eye. Instead
of using the mirrors and the paper screen AB, the
inclined planes, 0 D, o E, may be covered with white
paper, and viewed directly through the aperture.
But however the instrument be used, a mean of
several observations should be taken, the box being
turned round after each. When the lights compared
are of different colours, as daylight, moonlight, and
candlelight, the space A B is to be covered with a
piece of fine white paper, printed distinctly in a
small type ; the paper is to be brushed over with oil,
and the box being placed between the lights, it is to
be moved until the printing can be read continuously
along the paper, with equal case on both sides of the
line 0. Or the printed paper may be pasted on the
mirrors, or ~the inclined surfaces on which they rest,
and the print is then to be read through the opening,
which may be enlarged for this method of applying
the box.
Professor Wheatstone has constructed a photo-
PHOTOMETRY.
4'07
meter of greater accuracy'a'nd convenience than any
yet-contrived. It depends for its action on the per-
manence of the impression of light upon the optic
nerve, and is thus described by Professor Daniell :—
“ If a small convex reflector, such as a bead of glass,
about g-th inch in diameter, silvered on the inside,
be placed between two lights, bright images of both
will be formed, but differing in brightness according
to the intensity of each. A rough estimate of their
relative values may be obtained by adjusting the dis-
tances between the two ; but by causing the head to
move backwards and forwards in a straight line, two
parallel lines of light will be formed, about filo-til
inch apart, instead of two spots. By moving the
reflector to different parts of the line which joins the
two lights, or by changing the relative distances of
the lights themselves, these two luminous lines may be
made to appear perfectly equal in brightness. The com-
parative value of the lights may then be ascertained
by squaring the distances.” 1 In Fig. 1618 the instru-




Fig. 1618.
ment is represented of the full size. 0 o’ o” is a circle of
brass fixed to the wooden frame F ; the inside of the
brass circle is toothed, so that a smaller circle, 00'’,
half the diameter of the larger one, and toothed at its
circmnference, may engage the teeth of the larger
circle. The small circle turns upon its centre a’, and
is fixed to the arm a e’, which is moveable upon the
centre a of the large circle by means of a key on the
opposite side of the frame. The bright metallic bead
b is attached to the circumference of the small circle,
and as this circle is carried round by the arm a c’, it
also rotates rapidly upon its centre 0', and the bead
travels along the diameter of the large circle from b
to c in completing one half of its revolution, and back
again from c to 5 during the other half.
Count Rumford devised a method of comparing the
intensities of two lights by means of the shadows
which they respectively cast. The two lights are to
be so arranged that each may cast upon a plane white
surface a shadow of a small object, such as that of
a book or an upright rod, as in Fig. 1619: the eye
can form a tolerable judgment as to the relative dark-

(1) Chemical Philosophy. Second Edition. 1843.

ness of these shadows. The brighter light, which casts
the deeper shadow, is to be removed, or the weaker
light brought nearer, until the two shadows are equal-
ized. The distance of the two lights from the object


Fig. 1619.
which intercepts their rays being measured, the relative
intensity of the lights will be, as before, inversely as
the squares of the distances. The shadow of one
light is illuminated solely by the rays of the other,
while the surrounding space is illuminated by the rays
of both; when, therefore, the shadows are equal, the
lights are equal. Count Humford applied this method
to measure the variations in light, by a candle left
unsnuffed. Supposing the light furnished by a pro—
perly snufl’ed candle to equal 100, and it be allowed
to burn for 11 minutes, the light will then be equal
to only 39, and if allowed to burn without snuffing
for 30 minutes, it will only be equal to 16.
Professor Leslie’s photometer is constructed on
the assumed principle that light is convertible into
heat. It consists of the differential thermometer, of
which one of the bulbs is blackened and the other
clear: a glass case is put over the instrument to
exclude rays of heat. In order to use it, the light to
which it is exposed passes through the clear ball, but
is absorbed by the black, and supposing this light to
be converted into heat, the rise of temperature will
indicate the degree of illumination. The instrument
is certainly not correct in principle; it is in fact
nothing more than a delicate air thermometer.
A simple and ingenious photometer in use at the
Westminster Gas-works, consists of a disc of paper,
4: or 5 inches in diameter, the outer portion of which
is waxed, and the inner portion left plain, so that on
holding the paper vertically between the eye and a
luminous flame, the waxed portion is seen in the form
of a translucent ring, while the unwaxed portion
appears as an opaque disc. The disc is mounted ver-
tically upon a short cylinder of wood, sliding in the
groove of a horizontal frame, at the extremities of
which are fixed the lights to be compared This
frame also contains a scale graduated into feet and
inches. The sliding piece which carries the disc is
also furnished with a pointer, so that the distance of
the disc from either flame can always be ascertained
at a glance. In using this apparatus, the observer
stands on one side in such a position as to get the
disc fairly between his eye and one of the flames.
The waxed ring is then illuminated by the transmitted
light of the concealed flame, while the reflected light
of the front flame illuminates the opaque disc. The
paper is then moved to and fro until the transmitted
{L08
PIANO-FORTE.
light and the reflected light appear to be equal.
When this is seen to be the case on one side, the
observer passes to the other, where the conditions are
reversed, but the result is the same ; the light which
on the other side lighted up the opaque disc, now
illumines the waxed ring, and nice warm”? The dis-
tance of the paper from either light is then measured,
and the power of each flame is calculated as before.
PIANO-FORTE. This well — known instrument
belongs to that class of stringed instruments in which
the sounds are produced by imparting vibration to
elastic strings extended tightly over a case or box,
and covered with thin boards, the vibrations of which,
imparted to the volume of air which they enclose,
assist the deirelopment of sound.
It is remarkable that while poetry, architecture,
sculpture, and probably painting, attained their high-
est state of perfection among the ancients, it has been
reserved to the moderns to achieve excellence in music;
and the cause is closely connected with the superior
mechanical skill of the moderns. If the progress of in-
strumental music depend upon the perfection of the
mechanism of the instrument which gives it voice and
meaning, music, as a fine art, must be in a more ad-
vanced state now than at any other period, since our
mechanical resources were never at any former period
so great, or so fully developed. The music of the old
composers exhibits, in a very marked degree, the
capabilities of the instruments for which it was written,
and these were so limited, that to attempt to perform
one of the modern first-class compositions on a piano-
forte made forty or fifty years ago, would be like one
of the old stage-coaches attempting to compete with
a railway-train.
The old composers, in writing their orchestral and
concerted pieces, availed themselves in their studios
of such instruments as spinets, clavichords, harpsi-
chords, and afterwards of piano-fortes. These were
but feeble instruments, but the use of them by men
of genius “led to the peculiar capabilities of the
piano-forte being thoroughly studied and appreciated;
and the composers repaid their obligation to the in-
strument by writing for it many of the very finest
productions in music, and by practising the execution
of these productions to such an extent as to be able
to bring them before the public with the greater e’clai.
The importance which the instrument had thus gained
led from time to time to its improvement and enlarge-
ment; and this again to still finer compositions being
produced for it, and to the adaptation for the piano-
forte of all the best orchestral compositions ; so that
the advance of the art, and the improvement of the
piano, have had a mutual efi‘ect upon each other, until
it is now beyond all question the first of musical in-
struments, both to the profession and to the cultivated
classes of society."1
The instruments which immediately preceded the
piano-forte were extremely simple in their mechanism,
and'imperfect in their action. The clavichord con-
sisted of a piece ofbrass pin wire 6, Fig. 1620, placed

(1) M. Thalberg in ‘the Jury Report.

vertically in such a position, that on pressing down
the key k it would strike or press against the string 8
d .


\\\ \\\\\\\\\\ \\\\\\ \\\\ \\\ \\\\ \ ‘\\\ \"
Fig. 1620. THE CLAVICHORD.
just above it‘: the portion of the string to the left of
cl was free to vibrate, the other portion being muflied
by a piece of cloth, which also stopped the vibrations
of the whole string as soon as the finger was removed
from the key. The string was both struck and pressed
by the wire 6, and the sounds produced were of a soft
melancholy character.
In the spinet‘ the string was struck by means of a
piece of crow or raven quill, (hence the name of the
instrument, from swim, a thorn or quill,) attached to
the tongue of a little implement termed a jack, which
rose vertically from the further end 006
of the finger-key. The jack j, Fig. t 3 '
1621, was made of pear-tree wood, ' '
and the tongue 2!, through which the 85/
piece of quill g was passed, moved /
upon a swivel. When the key was
pressed down the jack moved up-
wards, and the quill was thus forced .
past the string, its own elasticity .1
giving way; and the quill remained
above the string so long as the finger
was pressed upon the key, thus al-
lowing the string to vibrate. On re-
moving the :finger from the key the
jack returned to its place under the string, and the
tongue, thrown back in passing the string, was forced
into its perpendicular position by the spring of a
bristle s b behind it, so that the quill opposed very
little resistance: at the same time a small piece of
cloth, fixed in the top of the jack, rested on the string
and served as a damper.
The spinet had but a single string to each note.
When two strings to each note were used, the name
of the instrument was changed into that of the harpsi-
chord, or horizontal harp. The strings were still
vibrated by means of quills, although from their rapid
wear, and the number of hours required to re~quill
an instrument, other elastic substances, of a more
durable nature, were tried, such as ivory and leather;
but the instrument is said to have lost in sweetness
by the change.
The idea of making the jack strike the string instead
of pulling it, ‘gave birth to the piano-forte. The value
of this idea seems to have been at once, and so exten-
sively appreciated; that the originator of it is lost in
the crowd of appropriators. Germans, French, and
English, all lay claim to the invention, and although
it is scarcely more than a century old, the date of its
birth is as‘ obscure as its country. We have met with
a notice of a hammer-harpsichord, as it is termed, as
early as 1711, with reference to the Giomale cZ’ItaZz'w
for that year for a description of it. It is stated that
the touch and mechanism of one that was brought, to
England were so imperfect, that nothing quick could

J
Fig. 1621.
PIANO-FORTE.
409
be played upon it, but that the “ Dead March in
Saul,” and other slow music, had a fine effect. In
the instrument named the nirginal, the strings were
struck with hammers consisting merely of the addition
of a leather button to the top of a piece of strong
wire screwed into the further end of the finger-key.
Thegreat defect of this simple hammer was, that it
did not instantly quit the string when it had struck
the blow, so that the sound was deadened'. This defect
is said to have been remedied by one Christoph
Gottlieb Schroeter, of Hohenstein, on the borders of
Bohemia, who in 17' 68 published an account of his
instrument, in which it is declared that “the per-
former can play piano or forz‘c at pleasure,” whence
is said to have originated the name of the instru-
ment.
More than 20 years before this, however, the instru-
ment is mentioned by name, on the occasion of a visit
made by John Sebastian Bach to Frederick the Great
of Prussia, in 1747, when it is recorded that the king
was so pleased with certain forte pianos manufactured
by Silberman of Freyburg, that with royal profusion
he purchased them all (15 in number), and placed them
in different rooms of his palace. On Baeh’s arrival
the king passed the evening in hearing the great
musician play. These instruments do not, however,
appear to have maintained their reputation, for it is
stated that eighteen years later, viz. in 1765, the king
ordered a harpsichord of the best kind from the most
celebrated maker of the day, viz. Tschudi of London,
the predecessor of Broadwood and Sons.
The piano-forte was not known in England until
about 1767, when it was introduced on the stage of
Covent Garden Theatre as “ a new instrument,” as
appears from the evidence of a play-bill of the period,
in the possession of Messrs. Broadwood. The harpsi-
chord makers of the day became manufacturers of the
new instrument, and a German, named Backers, be-
came celebrated as a maker. The name—board of a
grand piano by him is still in existence with the date
177 6. His contemporary, Zumpe, introduced some
important improvements, and he was followed by
others, many of whose names, such as Kirhman,
Broadwood, Stodart, Pohhnan, Beck, Clementi, &c.,
are still held in respect, or still represent important
firms in London.
There are three forms of piano-forte, viz. the grand
and the sgaarc, in which the strings are placed in a
horizontal position; and the aprig/ii, in which the
strings are vertical.
The form of the grand piano is the same as that of
the harpsichord, and was suggested by the varying
length of the strings. 'This form is well adapted to
the introduction of the best kinds of mechanism, and
is always chosen for first-class instruments. Each
note is produced by the simultaneous vibration of 3
strings ; but in order to lessen the cost of the instru-
ment, a form of grand piano has been constructed in
which there are but 2 strings to each note; such are
the oi-c/iord and semi-grand. There are also ooaa’oir,
or coiiage-graniZ-s, which have shorter strings and
occupy less room.

The form of the square piano is oblong rectangular,
the same as the German clavichord, and is probably
the first shape in which the piano appeared. It re-
mained an inferior instrument until the mechanism of
the grand was introduced into it, thus leading to the
variety called grand-square. It is difiicult in this
instrument to strengthen the framing sufficiently, and
the oblique position of the action with respect to the
strings and key-board is also an objection; neverthe-
less this form is the best substitute for the grand.
The aprig/it piano was at first a grand, set on end,
raised on legs 2 or 3 feet above the ground, and
struck at the lower end: this, the aprig/ii grand, as
it was termed, was unwieldy from its great height,
and was superseded by the cabinet, in which the
frame was brought down to the ground, and the blow
given at the upper end of the strings by means of
levers and long vertical rods communicating from the
key to the hammer. It formed an elegant piece of
furniture, and continued long in favour. Still, how-
ever, its great height (6 feet) and length of action
were unfavourable to delicacy and ease of touch.
About 1812 Mr. Robert IVornum introduced an up—
right piano-forte, the height of which was from 4. to 5
feet: this was the harmonic, a name afterwards
changed to coiiagc. In 1827 its height was still
further reduced to 3-;- fect from the ground, forming
the piccolo, which served as the model for many
others of different names and about the same size.
The compass of the piano was originally 5 octaves,
from 1? below the lowest note of the Violoncello, to the
fifth 1:‘ above. This was extended upwards to 0,
making 5% octaves, forming what were termed piano-
fortes “ with additional keys.” As the mechanical
resources of the manufacturer became enlarged, and
the music written for the instrument improved, an-
other half octave was added to F in the same direc-
tion, and afterwards, in the better class of instruments,
half an octave was added in the bass down to 0.
Another note was next inserted in the treble; and
thus the compass came to be from 000 (on the
organ 16 feet 0) to G, or 6% octaves. After this
another note was added, raising the scale to A. Grand
pianos now have 7 octaves, from A to A or G to G.
In the Great Exhibition was an instrument by Mott
with 7% octaves, and another by Pape, of Paris, with
8 octaves. In such cases the increased dimensions of
the sound-board are favourable to the general increase
in the power and tone of the instrument.
The manufacture of a piano-forte is naturally
divisible into four distinct classes of operations:—
I. Those relating to the flaming and sound-board.
II. The siringing. III. The lccgs and the aciion.
IV. The ornamental or other case, covering and en~
closing the whole.
I. When it is considered that the tension of the
strings in a full-sized grand piano amounts to about
25,0001bs., or between 11 and 12 tons, it will readily
be conceded that the framing, which serves as a strut
or stretcher between the two ends of the system of
strings, so as to keep them apart, must be of great
importance to the durability of the instrument, and
4.10
PIANO-FORTE.
its power of standing in tune. In the old instruments
the framing was of timber only, and the strings being
formed into loops at one end, were secured by studs
driven into a solid block of wood, named the string-
bZoc/r; while the opposite extremities of the strings
were wrapped round a series of iron pins called wrest‘-
pies, insertedinto another block named the wrest-plant.
The string-block and the wrest-plank were separated
by a strong framing of carpentry, but this, from the
very nature of the material, was insufficient to resist
the enormous strain, and in gradually yielding, the
instrument went out of tune. A defect of this
kind, of course, made it impossible to attempt to im-
prove the power and tone of the instrument by the
introduction of stouter strings, for that would have
aggravated the evil; but the makers were compelled
to use light strings, and be satisfied with truth
rather than power and depth of tone. At length,
however, the influence of the civil engineer extended
itself to this branch of industry, as it had already
done, or was doing, to nearly every other: cumbrous
machines of wood were every day being superseded
by the lighter, more elegant and efficient structures
of metal; and as the demand for metal increased, im-
proved methods of smelting and of working it were
discovered, new tools and appliances were invented;
the suggestions of science soon ceased to be imprac—
ticable when working engineers, abundance of metal
at a cheap rate, and intelligence in its application,
grew and multiplied.
The use of metal in the framing of the piano gave
the requisite strength. The studs on which the back
ends of the strings were secured, were attached to a
plate of wrought-iron, called the string-plate, curved
to the form of the hollow side of the instrument; from
this bars of wrought-iron or steel extended, longi-
tudinally, above the strings and parallel with them to
the wrest-plank, the ends of these bars being so
firmly connected with the string-plate and wrest-
plank as to sustain nearly all the tension of the
strings. The string-plate was screwed firmly down
to the timber framing below, and the bars were also
secured thereto at intervals, whereby great strength
was obtained. The more important parts of the wood
framing were of the soundest oak, dried and glued
up in several thicknesses. In the grand piano the
wood framing under the strings is severed across to
allow the hammers to rise, and in order to convey the
thrust across this opening, small thin arches of metal
are interposed, abutting on one side against the wrest-
plank, and on the other against the transverse rail,
forming part of the main body of the framing, and
called the telly-mil. The arrangements of metallic
bracing are, however, varied by different makers.
The surface of wood lying immediately under the
strings is called the sound-board,- it is formed of thin
boarding, of the best Swiss pine, quite free from knots
and flaws; it is cut in a particular direction of the
grain, and is strengthened on the under side with
small ribs: the edges are attached to the framing of
the instrument so as to leave the whole of the middle
portion free to vibrate under the impulse of the

vibrating strings. The tone of the instrument greatly
depends on the sound-board.
In square piano-fortes the strengthening is effected
by bolting the wrest-plank and string-plate firmly
down to a strong bed of timber, which extends
beneath the keys over the whole surface of the
instrument. In addition to this, one or two metal
bars are stretched across from the string-plate to the
wrest—plank, over and parallel with the strings.
In upright pianos the framing is most simple, on
account of the continuity not being broken. The
tension is maintained by means of timber struts
placed vertically at the back of the instrument, to
which the string-plate and wrest-plank are firmly
secured. Iron bracing is also adopted.
II. The stringing, as already noticed, was formerly
much thinner than at present. Steel wire was em-
ployed for the treble, and brass wire for the bass.
The length of the instrument did not give sufficient
length to strings of ordinary thickness for the lowest
notes : the strings were therefore increased in thick-
ness by lapping brass wire with a thinner one of
copper. Each string also consisted of a separate
wire, twisted at one end into a loop and passed over
a stud in the string-block, and the other end wrapped
round the wrest~pin. When heavier wires came to
be introduced, capable of resisting a heavier blow
from the hammer, this method of stringing caused
the strings to jar against each other: besides, it was
difficult to loop heavy strings. This led to the plan
of making one wire of double length serve as two
strings, by bending the middle of the wire round a
pin in the string-plate, and the two ends round
wrest-pins at the opposite end. This method was
patented by Messrs. Collard, 1827.
As the instrument increased in power, brass wire
was found to be too soft and weak, and steel wire came
to be solely used. For the lowest octave of the bass
notes lapped wire is used, the main wire being of
steel, and the lapping wire of soft iron for the upper
part of the octave, and of copper for the lower. The
lapping is now made quite close, instead of open, as
formerly. For each of the lowest bass notes of the
grand piano two strings are sufficient, and sometimes
only one.
In the stringing of grand pianos another improve-
ment was introduced, viz. that of the upward bearing
of the strings at the striking end. The length of the
vibrating portion of each string is determined by two
bridges, one attached to the sound-board, and the
other to the wrest-plank a little in front of the strik-
ing point of the string. Now supposing the strings
to bear down on these bridges, and the strings to be
struck from below, the tendency of the blow would
be to lift up the strings from their bridges, and for
the moment to increase their effective vibrating
length, which would obviously interfere with the
purity of the tone. By reversing the direction of
the bearing of the front bridge, or by substituting for
this bridge a plate pierced with a series of holes
through which the strings were passed, turning up
immediately to the wrest-pins, each string would
PLANO-FORTE.
All
evidently have an upward hearing at the front end,
and the effect of the blow would be to force the
string against its rest, instead of lifting it off as
before. This is shown in Fig. 1634.
111. We come now to the most important part of
our subject, the action of the piano, that is, the con~
nexion between the key-board and the strings, or, in
other words, the means provided for striking the
strings. The importance of the action in bringing
out the elements of expression which are peculiar to
the instrument, are well stated by Mr. Thalberg :—
“Between the mind of the player that conceives,
and the string that expresses by its sound the con-
ception, there is a double mechanical action; one
belonging to the player, in his fingers and wrists; the
other to the piano, in the parts which put the strings
in motion. No two piano-players touch the instru—
ment alike; that is, no two players have the same
mechanical action in their fingers, or produce the
same tones; and the difference in the style and
degrees of excellence of pianists is more owing to
this than to any other cause. It is, therefore, self-
evident, that that part of the piano which continues
the action of the fingers, and completes the connexion
between the mind of the player and the strings of
the instrument, should have a delicacy and a power
answering as near as possible to those of the hand of
the player. Every difference in the action of the
piano will give a corresponding difference in tone and
expression; and hence this part of the instrument
has at all times been justly considered of paramount
importance, not only by the great professional pianists,
but by the highly-cultivated amateur player.”
The first action in the piano-forte, properly so
called, was very defective, compared with, that to
which we are now accustomed. The key is, Fig. 1622,
was the same as in the clavichord, Fig. 1620. To the
key was attached a lifter Z of brass wire, furnished at
the top with a button of hide leather covered with




SINGLE ACTION.
Fig. 1622.
soft leather. When the key was pressed down, this
lifter struck the hammer it against the string a, and
caused it to vibrate. At the extreme end of the key
the nwpstic/t, or stie/cei', e, raised the damper [Z at the
very moment the hammer was raised to strike the
string; and it is evident from this arrangement, that
so long as the key was kept pressed down the string
would continue to vibrate until the force of the blow
upon the string were entirely expended ; but the
moment the finger were taken off the key, the sticker
e would fall down with the key, bringing the damper
(Z into contact with the string, suddenly arresting its
vibrations. This damper was a wooden lever, lying
horizontally over the strings, with a hit of cloth
attached to the free end. Another form of damper is

shown in Fig. 1623. It is a'bent‘brass ‘lever, moving
upon a centre, and in its normal state pressing, in
consequence of the superior weight of the lower arm 1,
E]
2.\ Q
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, )2
c v , __._--r"
\\\\\\\\\\\\\ ‘\ _\\\\ <\‘\\\\\Y\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\w
Fig. 1623.

DAMPER.
against the string at 6 from below. On pressing down
the key la, the lifter Z will rise, thereby elevating the
lower arm of the lever, and depressing the upper
arm, thus setting the string free to vibrate. On re-
moving the finger from the key, the superior weight
of the lower arm will evidently cause the brass button
to return to its original position. The piano-forte,
thus constructed, was called the singie action: it
continued long in use, even up to the commencement
of the present century. Its tone was thin and wiry,
and it had this serious defect, that unless the key
were struck with some considerable force, the hammer
did not reach quite up to the wire, and consequently
no sound was produced; and if, to remedy this, the
hammer-rest, under ii, Fig.1622, were placed nearer to
the string, there was danger of bloc/ting, that is, of
the hammer not leaving the wire immediately after
h s


Fig. 1624. HOPPER.
the blow. To remedy this defect, the lioppen /i, Fig.
1624:, was invented. This is a jointed upright piece,
attached to the back end of the key, and used to lift
the hammer instead of the stiff wire, or lifter. When
the key is pressed down, the hopper engaging in a
notch on the under side of the hammer, lifts it to
within so very short a distance of the string, that a
slight additional pressure causes it to strike; but in
the act of pressing down the key with suflicient force
to cause the hopper to lift the hammer high enough
to strike, the jointed part of the hopper in rising
comes in contact with a fixed button, and escapes
from, or naps out of, the notch, and allows the hammer
to‘fall clear away from the string. This mechanism,
called (tontie action, is still in use for square pianos.
Fig. 16% also shows at (Z what was long termed the
Iris/i damper, from its having been invented by an
fl 5..
p l
, _:> as»
I -——-~
~ \ ' m\n“m\\\m
_'—_"“_.<\\-T\\\ \mwmKR \ \\E\\§\‘.‘ \ ~'“
Fig. 1625. DOUBLE Ac'rrox.



Irishman named Southwell. It was simply an upright
rod with a piece of cloth at the top, which the rod
412
PIANO-FORTE.
raised from the string the moment the key was de-
pressed. This form was superseded by the crank-
damper (Z, Fig. 1625, attached to a separate lever
below.
The action of the hopper was not quite perfect.
The hammer, when liberated therefrom, fell upon a
rail covered with cloth, or some soft bed; but after a
forcible blow, the elasticity of the string struck sent
the hammer down upon its bed with such force, that
there was danger of its rebounding against the string,
damping the vibration and injuring the tone. This
was remedied by fixing to the back end of the key a
projection called a 06606, c, Fig. 1625, which caught
the head of the hammer as it fell, and held it down
until released by the pressure of the finger being
removed from the key. This combination of the
hammer, hopper, and check, known in England as
Me grand action, and in Germany as rZz‘e EngZz'sc/ze
Melcmzz'lc, is shown in Fig. 1626, in which I: is the
I
m 7'
H .

a":—
.. _ (\
a Q 4
,2: 7; X
W Yd
Z s



lv"_——\ i ' 'i/
mssmmmsm . .\\\\\\\ \\\ “
Fig. 1626. GRAND ACTION.
key, Z the ack or lever, 6 a button for regulating the
traverse of the lever, c the check, (Z the damper, s the
string, r’ the ruler, Z the damper pedal lifter, r r rails
and sockets, s the spring, and la the hammer.
There was still a defect in the ordinary action
which required a remedy. After the hammer had
fallen, it was necessary for the key to rise to its
position of rest before the hopper could again enter
the notch of the hammer, so as to be ready for an-
other stroke. The consequence of this was, that a
note could not be repeated without lifting the finger
the whole height. of the key’s motion, and allowing
time for the full rise before the note was struck
again. This difficulty was overcome in various ways,
but all the contrivances are so arranged, that while
the key returns, the hammer is held up at a certain
height near the string, by which means the hopper
can engage itself more quickly under the hammer, and
reproduce the note in less time, and with less labour
to the finger than before. This, the repetition move—
ment, as it was named, is shown in Fig. 1627. This,
with Fig. 1628, was patented by Messrs. Broadwood
for their grand action, invented by Mr. Southwell.
'———P7’) ,9
\
I 'Q‘\
. ‘ ‘
Q?’ ' 711% 'i‘
\
to’ P .r 1 f:
. it __
If.‘ ...... .. \\ \ \ \\\\ \\ \\\
u


Fig. 1627. BROADWOOD’S GRAND norms’.
In these figures 6 is‘ the key, Z the lever, 6 the button,
a the check, (Z the damper, s the string, 0' crank for
damper, Z’ damper pedal lifter, w" rails and sockets, s’

spring, and 6 the hammer. In the repetition movement,
shown in Fig. 1628, 6 6’ is a block passed through the
hammer-butt, s
a spring fixed
at the back of
6’, and pressing
upon the front of
it, the effect of
which is, that
when the lever
passes the notch,
it is caught by 6,
and the hammer is sustained at the height required.
By means of another spring .92, the action of s’ is
regulated, and the height at which the hammer shall
be supported determined.
In Mr. Wornum’s new grand action, Fig. 1629, the
repetition is differently arranged. In this figure is is



Fig. 1628. nnrn'rrrron MOVEMENT.





Fig. 1629. wormuM’s GRAND ACTION.
the key, 6 s hopper and spring, 6 hammer, a check, 6
button to set off the hopper, lzZ hopper-lever, 2 tie
attached to the butt of the hammer, s sustaining
spring linked to the end of the tie, and fixed in the
front end of the hopper-lever, the rising of which puts
the sustaining spring in action. This spring gives the
piano blow, and assists in the forte and repetition:
d f are the damper and fixings, r’ is the hammer ruler
and back touch, below 66 is a wooden spring to set
up the hoppers.
Messrs. Collard’s first grand action, the invention
of Mr. James Stewart, is shown in Fig. 1630, in which



k






\v ‘ o
. \ m fi \ ‘a \
\\\\\\ m“ 1‘ \\\mxs" '\-\ \ \\ w \\\W \\\‘T':
i Fig. 1630. cotmnn’s FIRST GRAND ACTION.
6 is the key, 6 the hammer, r the hammer rail, 6' the
jack or hopper, 6 the button, 68 hopper spring,
03 damper, a crank for damper, Z damper pedal lifter.
The simplicity of this action is a great recommenda-
tion. Since the date of its introduction this action
has been modified and considerably improved, as will
be seen from the enlarged view of it given in Fig.
1631. The parts sufficiently explain.,themselves, but
it may be useful to notice that the escapement, as it
is called, which offers a point of resistance to the
tail of the jack, admits of easy adjustment by screw-
ing the little cylindrical nut up or down, so as to
bring the jack into quicker or slower action : a 8 shows
the jack—spring which keeps the jack up to its work
under the butt of the hammer. The repeat spring is
PIANO-FORTE.
4:13
very simply and efficiently arranged; and at the top
of the check is a small projecting piece of leather
marked j”, which receives the fanciful name of capid’s-




his!
\e .. _\ \\ \\_,\
Fig. 1631. coLLAan’s GRAND PIANO ACTION.
icing, but it is sometimes called thejlg: it is important
in bringing the check into rapid action. This action,
in a rather more simplified form, Fig. 1632, is applied
to the best squares, named by Messrs. Collard semi-
grand squares. It will be seen that the escapement is
6 as
h"?
with.
a tit



Immune?‘ ~ v
' .— I § ' I l
Edi git “make-sari ' we
33G ‘V o
" ,T " ‘. amt
‘v \
' l
%’I;’:?:~‘J
e— FTP—‘ts ‘3 :s

TIL-Ah—

:‘ws ‘ I P \\\i
r
Fig. 1632. coLLAnD’s savanna: PIANO ACTION.
differently arranged, and that the hammer is in a
different plane. The tip of the jack in these figures
is shaded black, to indicate the plumbago with which
it is rubbed for the sake of freedom of action. r r’ are
sections of rails, which, of course, extend the whole
length of the key-board. In some cases, the extreme
ends of the keys are plugged with lead, to cause them
to fall quickly into their places, as soon as the fingers
of the performer are removed from the near éhd of
the keys.
Fig. 1633 represents an action known as Zeiier’s new
grand, in which the hopper 72. works in the key with



It,’
- "‘
‘.2 c _ ' ‘k
\.‘\( ‘\ Ea _W_____ggl
" ‘\‘\\\\<\\\\\\\\\\\\§\\\\\ \\\\\\\\\\.\\\\\\\\\\\\\\\\\\ \\\\\\\\\ \‘§\‘\“
Fig. 1633.





what is called a cz'rd’s moat/i ; the escapement part of
the hopper at e and the setting off is effected by the
button 6, working in the arched part above it a d; s
is the hopper spring, ii the hammer, c clieck, d damper,
f damper crank, r’ hammer rail.
Sebastian Erard’s action, patented in 1821, and

represented in Fig. 16841,. has been the subject of
considerable discussion.1 One of its objects is to
enable the performer to repeat the blow without
allowing the hammer to fall down upon its bearing
(a condition necessary to rapid execution), but that
the key should have a perfect and uniform command
over the hammer throughout its entire play, or that
the note may be'produced, “ to use an appropriate
phrase derived from steam machinery, either at half-
siro/re, at quarter-stroke, or in a word, at any fraction
whatever of the entire stroke of the key.” In this
repetition action there is neither butt nor notch
constructed on the arm of the hammer; but at a
point placed at a certain distance from the joint on
which the hammer plays, and under the arm, is at-
tached at a a small roller upon which the point
of the jack ii is directed centrically. When the key
is relieved in the slightest degree from the pressure
of the finger, the jack shifts its position a little under
the roller, and prevents the hammer from descending.
“After this, if the key be allowed to rise through the
smallest fraction of the stroke, the hammer will
descend through a corresponding fraction of its play,
the jack always holding its position centrically under
the roller, and the finger, therefore, whatever may be
the extent to which the key is allowed to rise, having
always a complete command over the hammer, and a
complete ability to reproduce the note.”
The mechanism by which these effects are pro-
duced will be understood from the figure. The key is,
with the pivot in the usual place, acts upon the
jack Z, as in the usual mechanism. The jack Z acts
upon the hammer ii through the medium of a com-
bination of levers and springs. The jack Z acts first
on the intermediate lever Z, to which is attached a
second jack ii, from which projects a rectangular arm
also marked Ii. This second jack sustains the ham-
mer by acting centrically on the roller 6’ already
alluded to. When the key is is depressed, the lever M,
the rectangular jack, the roller, and the hammer, are
severally raised. When the hammer-head is brought
within about an eighth of an inch of the string, the end -
ii of the arm of the rectangular jack is brought to
bear against the fixed pin Z2, by the reaction of which
the rectangular lever is turned on its centre, so as to
take the head of the’ jack from under the roller 12’,
which is at this moment dismissed from the jack, and
the hammer is projected against the string. When
the hammer recoils from the string, the roller falls
back upon the lever s’, which is urged upwards by a
spring 8, so controlled in this upward reaction by
another point of contact, brought about between the
spring and the hammer, that the latter cannot re-
bound against the string. Meanwhile the jack, no
longer centrically under the roller, has passed a little
to the side thereof, so as to form a tangent there with.
When the finger relieves the key slightly of its pres-
sure, the rectangular arm kit is released from the
action of the pin 5; and the spring 8 acting upon
the jack It draws it back, so as to bring it again under

(1) There is a. clever article on this subject in Dr. Lardner’s
work, entitled, “The Great Exhibition and London in 1851.”
4:14!
PIANO-FORTE.
the roller, the roller itself meanwhile being sustained
with the hammer by the lever s’ acting upon it by the
spring 8. With respect to the damper, in Erard’s
mechanism it is placed under the string instead of
over it, and the pressure which it exercises is pro-
duced by means of a spring acting upon the lower
end of the vertical red at, upon which the damper is



’ AY
:35 6: a3‘ _‘
e’ ‘ , ~ \ s
d Q 9, I7‘
,2. ll 8"?’ a 6
fi 4'“
l .1
l
uummu D Z n k
.\ i1 """"" _ , ..-.::-_'=.
\\\ ‘ " \ v‘\\\\\\'\\\'\\\\\s\\\\\\\\\ \\\\\\
Fig. 1634. ERARD’S ACTION.
placed. YVhen the key is depressed by the finger,
the jack Z raises the intermediate lever, the opposite
end of which acts upon the damper near w by means
of a shoulder formed upon it. When the short end
of the intermediate lever W is thus depressed, it
compresses the spring, and draws down the damper
from the string. When the finger is removed from
the key, the spring, relieved from the pressure of
the lever, acts upon the rod of the damper, which it
again presses against the string. The spring damper
thus substituted for that which acted by weight, is
said to have the effect of deadening the vibration more
suddenly than the old form, which is liable to a jump-
ing effect when let down upon the vibrating string.
We have now to notice the
arrangement of the action in
upright pianos. Mr. Wornum’s
zmz'gue piano, of which the action
is shown in Fig. 1635, was only
3 feet 3 inches high, and the strings
were all placed diagonally towards
the floor. s is the string, k the
hammer, r’ the hammer rail, it’ the
hopper, s s are springs, at damper
and wire, and f the damper rail.
This form of instrument was
superseded by the double or piccolo
action by the same inventor. Its
construction will be understood
from Fig. 1636, in which s is the



,, _ 7.
55 ___f
lllllllllll_ l I
\\\\ §\“\T\\\Y\'\W\\K\W\$W\\\ \\ \W\\\\\W§\§ W \'

Fig. 1635. UI’RIGHT ACTION.
string, is the key, k the hopper and spring, a the
check, 03 the damper wire, :a setting-off screw; the
upper it shows the hammer, and the lower 8 the ham-
mer rail. This action has the three desirable qualities
of delicacy, promptness and firmness of touch.
In concluding this notice of some varieties of
action which have been introduced into piano-fortes,
thereis one point requiring special notice, on account

of the general misunderstanding which prevails re-
specting it—namely, on what does the loudness of
tone in a piano-forte depend?
It is generally supposed to de-
pend on the degree of pressure
with which the keys are struck.
This is an error. The loudness
of the note depends solely on the
time taken to depress the key from
the general level of the key-board;
or in other words, the force of the
note depends altogether on the
velocity with which the hammer
moves through its arc; the greater
this velocity, the greater, in pre-


A
f’
“.35..
\
...._..... x5279,
\\\ \\\\\\ .\\ ~
<.,-~._ “-
' \
\\\\

\


Fig. 1636. PICCOLO Acrron.
cisely the same proportion, will be the force of
the blow given to the string, and the consequent
loudness of the note. If the note produced when
the hammer is raised in half a second have a certain
intensity, it will have double that intensity when
raised in a quarter of a second. “The finger,” says
Dr. Lardner, “ can produce no efiect whatever upon
the string, except by imparting more or less pro-
jectile velocity to the hammer; that this projectile
velocity depends solely on the time taken to depress
the key to its bed, and that all other action of the
finger, hand or arm which ‘has not for its effect to
depress the key with more or less expedition or
promptitude, is just so much power wasted. The
player may work his hands and arms,—he may raise
them a foot high above the key-board, and throw
them down again upon the keys,—he may gesticulate
as though he were engaged in a herculean task, but
the strings will not sympathise with his struggles,
and will respond with no more effect than they would
if the keys were put down with the same celerity and
promgtitude by the finger of an infant. It may
perhaps be asked, What, then, becomes of all the force
and momentum which the perspiring executant ex-
hibits in such cases? We answer, that it is expended
on the bed of the keys which receive these unavailing
and ungraceful thumps, but that for all musical pur-
poses, such force is absolutely wasted.”
IV. The preparation of the outer case of the instru-
ment belongs to the cabinet-maker, and will be noticed
among the following statistics.
The manufacture of piano-fortes is an important
branch of industry in the metropolis. In the London
Directory for 1853, the names of upwards of 200
“ piano-forte makers” are entered; although many
of these are sellers, or retail-dealers, as they may be
called. There are, however, a large number of small
makers, whose names do not appear in the Directory:
men who purchase the difi'erent parts of the action,
the metal work, 850., of large dealers in those articles,
and then put them together, much in the same way as
a watchmaker combines the diflerent parts of a watch
PIANOTOBTE.
415
which he does not himself make. Some of the small
dealers are, we fear, suiiiciently dishonest to put the
name of some eminent maker on their key-board, and
thus enhance the price of the instrument. At one
time, when the name of Tom/einson was a sort of pass-
port to an instrument, the small dealers would put
Tom/aisson on their name-boards, and thus escape the
notice of the law.
The number of subsidiary trades is also large.
Although in the London Directory there are only en-
tered 6 piano-fortefi'et cutters, 2 hammer and damper-
elot/z. manufacturers, a hammer-rail makers, 6 piano—
forte key-makers, 2 piano-forte pin-makers, 5 silkers,
1 stringer, and 29 tuners, yet there are a large
number of persons occupied as small makers of parts
of the instrument, and not being housekeepers are
not entered. And even if it were possible to make
this list complete, it would by no means represent the
extensive subdivision of the trade. In the manufac-
ture of a piano there are, in fact, upwards of to differ-
ent classes of operatives employed, each of whom,
with his assistants, is exclusively engaged in his own
peculiar branch of the manufacture. They are parti-
cularized in the following list 1:—--~
1. The key-maker forms the key-board in one piece,
by carefully glueing up a number of pieces of well
selected lime-tree wood, arranging his joints in such
a way that in afterwards cutting out the keys the saw
shall out along a glue joint instead of through the
solid wood. He then planes up the key-board, bores
the necessary holes, glues on the pieces of ivory,
scrapes and polishes them, and finally cuts the whole
up into separate keys with a fine saw.
2, 3, ll, 5. The hammer—maker, the clzec/e-ma/cer,
the damper-maker, and the clamper-lifter-ma/rer, con-
struct the parts of the action to which these names
refer.
6. The noteli-rnalrer covers with doeskin and cloth
the notches or ends of the hammer-shanks into which
the hoppers work.
7 . The lianimer-leatlzerer covers the hammer-heads
with their different coats of leather and felt, and cuts
them to their proper sizes. .
8. The learn-maker makes the mahogany beam or
rail extending across the action, and covered with
brass in which the hammers are centered.
9, 10, 11. The lrass stad-ma/rer and brass li'iclge-
nza/lrer form the upward bearing-studs and bridge;
and the wrest-pin-rna/rer makes the iron tuning-pins.
12, 13, 141, 15. The metallic brace-maker, the
metallic plate-maker, the steel arc/z-ma/cer and the
t1 ansnerse tar-maker, all construct parts of the metallic
bracing. [The makers of the iron and brass work,

(I) This list was furnished by Messrs. Broad wood to Dr. Lardner
at the time of the Great Exhibition. A second list from the same
source gives the names of the materials required in the construc-
tion of a piano-forte, specifying the parts of the instrument where
they are used. Some of the statistics are from a clever paper on
piano-fortes, chiefly with reference to those of the Great Exhibi-
tion, inserted in Newton’s London Journal, 1851, which has been
of assistance to us in the preparation of this article. We are also
indebted for information to the article PIAh'O—FORTZ in the Penny
Cyclopaedia, and to Messrs. Collard_'& Collard, and to several other
gentlemen in the trade.

for piano-fortes and other musical instruments, are
called masie-smit/ia]
16. The span strinymza/eer makes the lapped or spun
wn'es.
17, 18. The sang/er saws the timber roughly into
shape; the lent siclerna/rer then cuts it more accu-
rately to its size and thickness, and bends, by means of
steam, the pieces destined to form the curved side of
the instrument.
19, 20. The case-maker fashions, puts together
and veneers the timber framing forming the principal
body of the instrument; he also forms and fixes the
wrest—plank. The braver inserts the timber cross-
bracing in the frame; but this is sometimes done by
the case-maker.
21. The bottom-maker makes and fixes the framed
bed at the lower part of the instrument, to receive
the keyboard.
22, 23. The soanzling-loarel-maler selects the timber
for, cuts out, and joints the sound-board. The belly-
man planes it to its proper thickness, shapes it,
finishes it, and fixes it in the case. He also forms
and fixes upon it the beech bridge upon which the
strings take their bearing. '
241'. The marker-0f marks out the scale for the
strings, fixes the pins in the beech bridge, and finishes
it to its proper shape; he inserts the upward bearing
bridge and studs in the wrest-plank, and bores it for
the reception of the tuning pins; he also fits and
fixes the metallic string-plate, longitudinal stretcher
bars, and other parts of the metallic ‘bracing, by which
the piano-forte is made ready to receive the strings.
25. The stringer puts in the strings and fixes the
wrest-pins in their places.
26. The finisher receives the keys and various parts
of the action from their respective makers; he con-
structs the action-framing, puts the action together,
fixes it in its place, and brings the whole of the
mechanism generally into playing order.
27 , 28. The rougher-a]; then tunes the instrument
for the first time, stretching the strings to their pro-
per tension; after which the tuner puts it thoroughly
and permanently in tune.
29, 30. The regulator of action then examines and
carefully adjusts every part of the action, and com-
pletes the regulation of the touch; and finally, the
regulator of tunes examines the tones and corrects all -
irregularities, making the sound of the instrument
perfect throughout.
In the course of the construction of the instrument,
the following operations, which relate to the exterior
of the instrument, are performed :—
31, 32. The top—maker constructs and veneers the
cover, and puts on the hinges. The plint/zer fixes and
veneers the plinth.
33. The fronter shapes, hinges, and centres the fall
or cylinder front ; shapes the cheeks, makes and
fixes the mouldings, puts on the locks, and attaches
the ornaments.
3a. The eancas-franze-nza/aer makes an open wood
frame-work, covered with canvas, which is fixed in
the bottom of the instrument.
416
PIANO-FORTE—PIN.
35. The lyre-maker makes the lyre-shaped bracket,
fixed under the instrument to carry the pedals.
36, 3'7. The leg Mock-maker makes and fixes the
blocks into which the legs are screwed; and the Zag-
makcr makes the legs.
38, 39, 410. The tamer, the carver and the gz'ZrZer
do all work required in their respective departments.
41, 4.2. The scraper scrapes and cleans the surface
of the case, and prepares it for the French polisficr.
The progress of the various works must not be
hurried; a grand piano ought to occupy at least six
months in its manufacture.
It was estimated at the time of the Great Exhibi-
tion that the number of piano-fortes manufactured
in London was about $50 per week, or upwards of
23,000 per annum: that some of the largest houses
made from 1,500 to 2,500 per annum each, or one-
tenth of the whole: that of the annual make, between
5 and 10 per cent. might be estimated of the grand
form; about the same of the square; and the re-
mainder, forming by far the largest portion, of the
upright form. The prices in plain mahogany cases
were, for grands, 125 to 135 guineas ; for bichord and
small grands, 80 to 105 guineas; for grand squares,
50 to 100 guineas; for plain squares, 35 to 50 guineas;
for cabinets, '7 5 to 80 guineas; for cottage and other
small uprights, 415 to '70 guineas. These prices might,
however, be greatly increased by employing highly
carved and ornamented cases. Messrs. Oollard’s prin-
cipal instrument at the Exhibition was valued at 500
guineas, Messrs. Erard’s at 1,000 guineas, and Messrs.
Broadwood’s at a still higher price. By way of use-
ful contrast to these expensive instruments, Messrs.
Collard exhibited a small upright piano in a neat plain
case of varnished Swiss pine or other cheap wood:
they sell instruments of this class largely at 30
guineas each. ,
The following estimate of the value of piano-fortes
annually made in London, is from the able paper last
quoted :—
1,500 grands, bichords, and small grands,
£165 000
at, say £110 each ’
1,500 squares n 60 ” 90,000
20,000 uprights of
various kinds} ” 35 n 700,000

23,000 Total value £955,000
or nearly a million pounds sterling per annum. The
number of workmen engaged in this production is
estimated at between 3,000 and 4,000. The export
trade is also large.
The extent of the manufacture in France is only
about one-third that of England.
We are assured that this estimate is much too low
for the present year, 1853. The piano-forte makers
of London are not only 'in full employment, but are
not able to keep pace with the demand. . We are in-
formed by an eminent maker who is now producing at
the rate of from 4.0 to 50 pianos per week, that he
could readily dispose of three times that number if he
were in a condition to make them. A. gentleman in-
timately connected with the piano-forte trade, has
furnished us with an estimate of the produce of the

various makers of Great Britain, from which it
appears that about 1,500 pianos are manufactured
every week, by far the larger number of which are
produced in London. Of this number, 35 are grands,
20 squares, and 1,450 uprights of all kinds, including
cabinets, cottages, semi-cottages, and piccolos. Of
these varieties, cottages and semi-cottages are made in
the proportion of 300 per thousand, piccolos 699 per
thousand, and cabinets only 1 per thousand. Now,
taking this weekly produce as above stated, and assum-
ing the prices to be the same as those given in the
“ London Journal,” .we thus arrive at the annual value
of the piano-fortes manufactured in Great Britain.
Grands............ 25 x 52 = 1,300 at say £110 each £143,000

Squares ......... .. 20 x 52 = 1,040 ,, 60 :2 62,400
Uprights ....... .. 1,450 x 5'2 =75,400 ,, 35 ,, 2,639,000
Number of Plano'fortes} 77,740 of the value of £2,844,400
per annum......

PIOAMAR. See Tan.
PIOROLITE. See Snnrnnrrnn. _
PIOROTOXINE, the active principle of coc-
caZas z'rzcZz'cas. It forms small, colourless, stellated
needles of an intensely bitter taste; soluble in 25
parts of boiling water, and in 3 of boiling alcohol.
It is said to contain (3121:1705.
PIER, from the French picrrc, stone, a term ap—
plied to the pillar-like masses of masonry or brick-
work from which arches spring, rising from what is
termed the impact‘ capping of the pier, which usually
consists of a series of mouldings. See Burner),
sec. III.
PIETRA DURA. A term applied to the black
marble used for inlaid works.
_ FILE-ENGINE. See Bnrnen, sec. IIL—STEAM.
I PIN. The manufacture of pins furnishes employ-
ment to a large number of persons; for according to
the ordinary mode of making them, each pin passes
through fourteen pairs of hands before it is ready for
use, without taking into account its previous prepara‘
tion as mere wire. The pin-maker receives this wire
in a very soft state, and covered with a scurf or oxi-
dation from the annealing process. To make it clean,
hard, and of the fineness required, it is pickled in dilute
sulphuric acid, washed, beaten, and dried, and finally
wound on a reel or barrel. The loose end is then
filed, passed through a draw-plate, and attached to an
iron barrel, which is turned by a horizontal handle.
By this drawing process the wire is reduced in size
and rendered hard and bright. It is next pulled from
the barrel through another draw-plate to straighten
it, and is then run out upon a low wooden bench or
trough twenty feet long, which serves as the measure
of the lengths into which the wire is out. These
lengths of 20 feet are next cut with shears worked
by the foot into shorter lengths, each about sufficient
for 6 pins. The pin—wires thus obtained are pointed
at each end at a machine called a mill, consisting of a
circular single-cut file, and a. fine grit-stone. The
pin-wires are applied 50 or 80 at a time, first to the
file which points them, and then to the stone which
polishes them, the grinder meanwhile spreading them
out, and giving them a rotatory motion by the action
PIN.
417
of the thumb and fingers. This employment was for-
merly exceeding injurious, but has been rendered less
so by efiicient factory ventilation. Without due pre-
cautions the fine particles of brass are inhaled and
produce consumption, or enter the eyes and induce
blindness. One pin is next cut from each end of the
wire thus pointed, the intermediate piece being again
delivered to the grinder to have its blunt ends pointed.
Two more pins are then cut off, leaving the middle
piece again to be pointed at each end. This middle
piece is now divided in the centre, making the third
pair of pins obtained from one wire.
Meanwhile the preparation of the pin-heads has
been going on under the hands of another set of work-
people. The wire for this purpose is much finer and
softer than that for pins, and it is prepared by wind-
ing it in a close coil round a mould or wire 40 inches
long, of the thickness of the pin. This coiling is
effected by means of a small lathe, or Jersey spinning-
wheel, to the spindle of which the mould is fastened,
The heading wire is fastened to the end of the spindle,
and passed, together with the mould, through two
small loops in a wooden handle, which the workwoman
holds in her left hand to regulate the winding, while
her right turns the wheel. In this way a rotatory
motion is communicated from the spindle to the mould
wire; and the heading-wire being held at right angles
to it, is closely coiled round it nearly from end to end,
and is afterwards slipped off to make room for
another. The disengaged coil is next out up into
heads, from two to two and a half turns of the
spiral being the quantity required for each head.
The cutting of the heads is effected by a sort of
guillotine, the action of which is as follows :—
A sharp chisel fixed vertically in a wooden frame is
held down by a spring: a lever, proceeding from the
upper part of the chisel, becomes engaged for a mo-
ment in one of the cogs of a wheel rotating near it:
this depresses the lever and raises the chisel: then
the lever, immediately escaping from the cog, the
spring forces the chisel down; but no sooner is the
chisel forced down than another cog comes into action,
depresses the lever and raises the chisel: in this way
the wheel, being furnished with a number of cogs,
gives to the chisel a rapid chopping 'motion. Under
the edge of this chisel the spirals, placed on a hori-
zontal board, are gradually advanced, in so regular a
manner that two turns of each spiral are cut off at
each descent of the chisel.
The next operation is heading the pins, and for this
purpose a boy takes a number of heads in his apron,
and taking up a few headless pins in his fingers, he
plunges them into his lap and works them about
among the heads with a sort of threading motion.
Most of the wires in this way catch up a head, some
two or three heads, which superfluous ones are rapidly
removed, and they are now ready for moulding or
fixing securely the heads to the shanks. To efiect
this a man presses his foot upon a treadle, which,
acting upon a lever, raises a weighted square bar of
iron; he then places the pins point downwards, and
one at a time, in a steel die, and suddenly removing
VOL. II.

his foot from the treadle, the bar descends, strikes
the top of the pin, and at once shapes and fastens it.
A small spring below the die prevents the pin from
passing deeper into the die than two-thirds of its
length, except when the heavy hammer descends and
drives it home; as soon, therefore, as the blow is
struck, and the man again presses the treadle, this
little spring comes into operation, and raises the pin
one-third out of the die, so that he can instantly
remove it and insert another pin. An expert work-
man will fasten the heads of fifteen hundred pins per
hour.
As far as the process of making the pin is con-
cerned the work is now complete, but there remain
several other operations to fit the article for use, and
make it bright and clean. Pins are cleaned by boiling
for half—an-hour in sour beer, wine lees, or a solution
of tartar; after which they are washed. They are
then whitened or tinned, by being laid in strata, in a
copper pan, alternately with grain tin in the propor-
tions of about six pounds of tin to seven or eight
pounds of pins, until the vessel is filled. Water is then
added, and heat applied; as soon as the water gets
hot its surface is sprinkled with four ounces of cream
of tartar, after which it is allowed to boil for an hour.
This operation is repeated once or twice, the pins being
washed in cold water between each boiling. After
tinning, the pins are polished by agitation in a leather
sack filled with bran, and after the bran has been
separated by winnowing, the pins are collected in
bowls for papering. '
Crimping-irons are used to fold the papers which
are to be filled with pins. Two of the folds are
gathered together and placed with a small portion
projecting between the jaws of a vice, which close
with a slight spring, and which have grooves chan-
nelled in them to serve as a guide to the paperer,
generally a girl, who sits before the vice with her lap
full of pins. Passing a comb into the heap, she
catches up a number of pins, the heads of which rest
between the teeth of the comb. She takes them up
and quickly runs them into the folds of the paper,
regularityin so doing being preserved by the channels
in the vice along which she drives the points of the
pins. As soon as one row is complete she puts two
more folds in the vice. Occasionally she drives the
pin with too much force against the vice and bends
it, when it is immediately taken out and thrown aside
among the waste, which in this manufacture is
reckoned at one-thirteenth of the total number of
pins fabricated.
The above processes have been accomplished chiefly
or entirely by machinery, and great fame was acquired
by what were called solid-headed pins, where the head
was not separate, but was raised from the wire itself
by strong mechanical compression. A chief objec~
tion to these pins arose from the necessity of their
being made of a softer wire than others, and there-
fore being very liable to bend. One of the most com-
plete of the pin-making machines was that patented
by Wright, in 184:4}. In this machine, “the rotation
of a principal shaft, mounted with several cams, gives
EE
4118
PINT—PIPE—PISIil-WORK.
motion to various slides, levers, and wheels, which
work the difierent parts. A slider pushes pincers
forward, which draw wire from a wheel at every rota-
tion of the shaft, and advance such a length of wire
as will produce one pin. A die cuts ed the said
length of wire by the descent of its upper chap; the
chap then opens a carrier, which takes the pin to the
pointing apparatus. Here it is received by a holder,
which turns round, while a bevel-edged file-wheel
rapidly revolves, and tapers the end of the wire to a
point. The pin is now conducted by a second carrier
to a finer file-wheel, in order to finish the point by a
second grinding. A third carrier then transfers the
pin to the first heading-die, and by the advance of a
steel punch the end of the pin-wire is forced into a
recess, whereby the head is partially swelled out.
A fourth carrier removes the pin to a second die,
where the heading is perfected. When the heading-
bar retires, a forked lever draws the finished pin from
the die, and drops it into a receptacle below.”
The consumption of pins for this country only, is
calculated at fifteen millions daily.
PINGHBEOK. See BnAss.
PINE. See WOOD.
PINT, the half of a quart, and the eighth part of
a gallon.
PIPE. According to the old wine measure, 2 hogs-
heads made a pipe,- but 2 hogsheads of ale or beer
made a butt.
PIPE. A channel for the conveyance 'of water,
gas, &c. See CAsrINe and FOUNDING—GAS—LEAD
—Por'.rnnr and PoncELAIN, &c. A method of
forming stone pipes is described under MARBLE,
Fig. 1395.
PIPFi—CLAY. See CLAY.
PISE-WOBK. A method of constructing very
durable walls of kneaded earth. It was probably
suggested by the building processes of the ants:
Pliny names these walls formacz'e, and the method of
constructing them was well known to the ancients.
Any kind of earth that will sustain itself with a small
slope, is adapted to the purpose; but that best suited
to it is clay, containing small gravel of sufiicient con-
sistence to be dug with a spade. It is first well
beaten, then screened to separate stones larger than
a common hazel nut; after which, it is wetted suffi-
ciently to enable it to retain the form given to it by
kneading between the fingers. It is now fit for use,
and in applying it to build a wall, a sort of moveable
=:
g;
.l
'—..._.___..—-e
---.~-,.
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= :
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...—:_=‘ p
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Fig.1637.
box or mould is made for the intended wall of deal
planks put together with their joints ploughed, and
tongued, and strengthened with clamps on the out-

side. These frames, one of which is shown detached
in Fig. 1637, are made 10 feet in length and 3 feet
high; they rest on cross pieces or putlocks, which
pass through the thickness of the wall, and near the
ends are mortices, into which are placed upright
pieces, 5 feet long, secured by wedges at the bottom,
and tied with ropes r, Fig. 1640, at the top. A cross
piece, an upright, and a wedge are also shown sepa-
rately in Fig. 1638. These uprights m
are set to the intended thickness of the wall, which is about 20 inches ' if
at bottom, and gradually diminishes upwards. The frames are steadied at the top by means of cross sticks
or struts s, Fig. 16A0, and the ropes
are made tight by twisting them with
a small piece of wood placed between
the folds. The frames being properly
fixed, the earth is thrown in, and
worked like concrete or mortar; to
allow the putlocks to be readily with-
drawn, the parts about them must be well wetted. In commencing a wall, 1
the first frame is put at one of the y
l
l
'l
,
n
t.
extremities, and the end of the
frame closed by planks secured by iron cramps, as shown in Fig. 1639; '
my y
t
till?
l
. I: ‘ll
{PW—M $32 (I
_._. __ _ ,-—---_-~———4 .'~ :2 _
5.1-:- = = : .__-_—__._r:'_—-—-———‘_”‘?:.=="
'35: .__—---_ -—-"-_—~—'__=________ a. .. ..__-._. W-——"===.__- .__.


Ems?

Fz'g. 1638.
at the other part, where there is no end, the wall is
to be sloped off at an angle of about 60°, for facility
in joining on the next piece. In commencing the
work, the bottom being well cleaned and sprinkled


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ntill-tilinlelllltlmm







with water, the labourers bring the masons the pre-
pared earth in wicker baskets, of the form shown at b
Fig. 1640, and tread it with their feet into a bed 3 or
Ll inches thick; they then ram it down with a rammcr,
a‘, Fig. 164.0, consisting of a block of ash, elm, or hazel,
10 inches high : square at the middle of its height,
6 inches by 5, diminishing in thickness, and termi-
nated by rounded edges at the bottom: towards the
upper part it is terminated by a circular surface,
4c inches in diameter, in the centre of which is a
hole for the handle, which is 4: feet 2 inches long.
PISll-WORK.
419
1n ramming, it is turned round at each stroke,
so as to make the work more compact, and unite
it with that previously done. By means of the
rammer, the first layer is reduced in thickness about
one half, and on this compressed bed another layer
is spread out, and beaten in the same manner, and
so on, until the case is filled. The frame is then
taken down, and moved further on, so that the plank






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Fig. 1640.
PROCESS OF BUILDING A WALL IN PISIiZ.
6?; ' *2’
Qvwa
entirely covers the inclined part.
over all the apertures, and the finished portions are
left for some months to dry. The surface may then
be coated with plaster, and the wall is finished.
Fig. 164.0 will show the method of building a wall
in pisé, and the arrangement of the frames FF, the
mode of securing them by the uprights U U passed
into the putlocks r r, and secured by the wedges w w.
The mode of terminating the piece of wall in progress
Lintels are placed
r "w?" by means of an incline is also shown; and in the
__ ' opposite wall the junction of two pieces is shown by
l’ t; the diagonal lines. The small open square holes mark
;jgi-lfgl l": the places occupied by the putlocks, which were with-
’:Lg—l [ drawn on raising the frame a course higher. It will
} be seen that the first few courses of the wall are of
\
masonry. This is for the
purpose of keeping the foot
of the wall out of the wet.
Fig. 1641 shows a house
nearly finished. This kind
of work is very durable; and
as an illustration thereof,
Rondelet states, that in
17 611 he repaired a chateau
in the department of Ain,
which was at least 150
years old, and that the
walls had acquired a hard-
ness and compactness
equal to ordinary stone;
so that in enlarging the
windows and other aper-
tures, the men used the
same tools as in a quarry.
9 % Qwiv I
0* o s
¢"¢:§£%$ Q ~
9 Q
reassess
es ‘352'.
Q’.
fig. 1641. HOUSE BUILT m’ P1512‘.
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egyg,
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420'
PITOHSTONE—PLAN E.
6'06 1 Walls, as they are termed in Devonshire, re-
semble pisé~workz they are formed of clay, loam,
and! chopped straw, and are generally 2 feet thick,
resting on brick or stone foundations, 3 or 4: feet
above ‘ the level of the soil; they must be carried up
at several times, and not be hurried. After each
addition, the sides are carefully pared down with an
iron cob parer, which resembles a baker’s peel.
When‘ dry, it is coated with fine stucco or plaster,
and if 1 kept 'dry at its top and foundation, it is very
durable. It is usually tiled or thatched at top.
PIlSTOL. See GUN.
PIISTON. See PUMP—STEAM, &c.
PTTL'CBANE. A term sometimes applied to the
common wharf crane. See CRANE, Fig. 679.
PIITCH. See TAR.
P'llTCHSTONE. A volcanic product, resembling
OBSIDIAN,1)1113 less perfectly glassy; it has a pitch-
like In stare. ~
Pll'Ih'PAGAL. See Tan.
PilliAi‘INlE. The plane used in carpentry is a chisel
set iina stock or guide, for the purpose of regulating
the depth to which it penetrates the wood, so as to
enable it to out instead of split the wood, and also
for furnishing a well defined guide to the path or
direction of the cutting edge. The sole or stock of
the plane is usually an accurate counterpart of the
form. which it is intended to produce, and as in the
majority of instances this is flat or plane, the instru-
‘ment derives its ‘name from this form. The sections
of planes may, however, be concave, convex, or
mixed; .as well as straight, whence arise those nume-
rous varieties known as grooving planes and moulding
planes» Planes used for flat surfaces are termed by
the jbirlers bench planes, or ear/facing planes. These
are all‘ similar as it regards the arrangement of the
chisell, .or tron as it is termed, but the size may vary.
In ordinary bench planes the width of the iron
ranges? from about 2 to 2%- inches. The names and
dimensions of surfacing planes are given in the
following table :—
Length in Width in Width of
‘ Inches. Inches. Irons.
Modelling 'planes, similar to a
smoothing planes .......... 1 to 5 i to 2 TI to 1%
Ordinary; smoothing planes 6:2,; to 8 g to 3% 13,3 to 2%
- Rebate planes.................... . 9% gm 2 1;’; to 2
Jack planes ........................ .. 12 to 17 23,} to 3 2 to 2%;
Panel planes 14g 33,} 2%,-
Trying planes 20 to 22 3111130 3% 2% to 2%,:
Long planes 24 to 26 3% 25
Jointen planes 28 to 30 3% 2%
Cooper’sJointer planes ....... .. 60 to 72 5 to 5% 3%; to 35}
Of'th'ese planes, those most commonly used are the
jack-plane for the coarser work, the trying-plane for
giving; the work ‘a better figure, or trying its
. straightness and accuracy, and the smoothing-plane
for finishing the surface. When the wood is very
rough and dirty, two jack-planes may be used.
_ '1‘hedifi‘erent parts of the ordinary surfacing-plane
will be understood by referring to Fig. 16412, in which
the line is s’ is the 8062 ,- m 6, the line on which the plane-
iron is supported, the 6ecZ, and this in planes of com-
mon pitch is usually at an angle of 45° with the per-
pendicular. The narrow opening between the face of =

the iron and the line at a)’ is termed the moat/t of the
plane ; the line m w’ is called the wear : the angle be-
tween the mouth and the wear should be as small as





Fig. 1642.
possible, so that as the sole wears away, or is corrected,
the mouth may not be too much enlarged; this angle
must, however, belarge enough to allow the shavings
to escape freely, otherwise the plane will c/zolac.
The line f is the front, and its angle is usually set
out i— of an inch wider on the upper surface than the
width of the iron. The iron is fixed in its place by
a wedge w, by slightly driving it between the face of
the iron and the shoulder m n. The wedge, shown
separately in Fig. 16413, is cut away at the central
part, to clear the screw which
connects the two parts of the
iron, and to allow space for
Fig.1643.



the shavings to escape. The
wedge is loosened by tapping
the end at c, or the top at t,
or by tapping the side of the
wedge itself; it may then be pulled out. A blow on
the front of the plane at f sets the iron forward or
deeper. rl‘he iron is somewhat narrower than the
stock, and the mouth vis a wedge-shaped cavity.
l/Vhen the stock terminates at the dotted line 8” s", it
represents the smoothing-plane ; when of the full
length with the handle or toat, it is the jack-plane or
panel-plane. The sole of the plane rests upon the
face of the work, and the cutter stands as much in
advance of the sole as the .thickness of the shaving,
which is so bent as to allow it to creep through the
mouth up the face of the inclined iron. Considerable
advantage is gained in having a double iron as in Fig.
, 161414., the top iron not being intended to cut, but to pre-
sent a more nearly perpendicular wall for the ascent of
the shavings, and as this iron more effectually breaks
the shavings it is termed the Meals-iron. The lower

\§\-\_\ Lid—'—
\
Fig. 1644.
piece is the one that cuts; the upper piece or top
iron has a moderately sharp edge; it is placed from
,lgth to 316th of an inch from the edge of the cutter,
and the two are held closely together by a screw passing
through a long mortice in the cutter, and fitting into
a tapped hole in the top iron. By the addition of
the top iron the plane works more smoothly, but
harder, and the more so the closer it is down, show—
ing that its action is to break or bend the fibres : the
shaving, being very thin, is constrained between the
PLANE.
151
two approximate edges, and as it were bent out of
the way to make room for the cutting edge, so that
the shaving is removed by absolute cutting, not by
being split or rent off.
The angle at which the plane-iron is inserted in
the stock depends upon the use to which it is applied.
The spoke shave is the lowest of the series, its incli-
nation being from 25° to 30°. In bench planes,
for deal and similar soft woods, it is 45° from the
horizontal line; this is called the common pile/z.
In bench planes for mahogany, Wainscot, and hard or
stringy woods, the For/e pitch, or 50°, is used. In
moulding-planes for deal and smoothing-planes for
mahogany and similar woods, the middle pitch, or 55°,
is used. In moulding~planes for mahogany and
woods difficult to work, (of which bird’s-eye maple
is said to be one of the worst,) lzulf pile/l, or 60° is
adopted. Close hard woods, such as box, may be
scraped smooth in any direction of the grain with a
cutter placed perpendicular, or even inclined slightly
forward. A tool with the cutter so arranged is called
a scraping-plane, and is used for scraping the ivory
keys of pianofortes, and works inlaid with ivory
brass, and hard woods. In the process of veneering,
use is made of a scraping-plane, with a perpendicular
iron grooved into a series of teeth instead of a con-
tinuous edge, for roughing or scratching veneers, and
the surfaces to which they are attached by means of
glue. In the smith’s plane for brass, iron, and steel,
the cutter is vertical.
Planes work smoothly with the grain of the wood,
which must always be considered in the operation of
planing. Some of the ornamental woods however owe
their beauty to the extreme irregularity with which
their fibres are arranged, and in certain directions the
fibres are liable to be torn up by the plane. By apply-
ing the smoothing-plane at various angles across the
different parts of the surface, the desired effect may
be attained; but with some curly, knotty, and cross-
grained woods, the steel scraper must be used instead
of the plane. The steel scraper (which had its
origin in a piece of broken window-glass, still used by
some of the gun-stock makers) is made of a thin
piece of saw-plate ; the edge is first sharpened at
right angles upon the oil-stone, and is then burnished
square or at a small angle, so as to throw up a trifling
burr or wire edge. The scraper is held on the wood
at about 60°.
Hard woods admit of being planed across the
grain, both with flat and moulding-planes. With
deal and other soft woods if a cutting edge be applied
to the fibres, parallel with themselves, or laterally,
they are liable to be torn up and present a rough un-
finished surface. A keen plane of low pitch is there-
fore used for such woods, and it is made to slide
obliquely across the wood, so as to attack the fibres
from the ends. Moulding-planes do not admit of this
application; mouldings in soft woods are planed
lengthways of the grain, and added as separate pieces :
but as rebates and grooves are frequently required to
be made across the grain, the obliquity is then given
to the iron, which is inserted at an angle, as in the

skew-rebate and fillz'sler, and the stock of the plane is
arranged in various ways to guide the iron. Fig. 16%
is the back view, and Fig. 16416 the side of a side-
fillister, for planing both with and across the grain; as


Fig. 1645. Fig. 1646.
in planing a rebate round the margin of a panel.
The loose slip or fence f is adjusted to expose so
much of the oblique iron as the width of the rebate;
the screw-stop s, at the side, is raised above the sole
of the plane, to suit the depth of the rebate, and the
small tooth or scoring-point p, shown separately at p,
Fig. 1645, precedes the bevelled iron, and divides the
fibres so as to make the perpendicular edge true and
square. The plougli is also a grooving plane, in which
the fence is secured to two transverse stems, passing
through mortices in the body of the plane, and fixed
by wedges. Slit‘ rleul pluues belong to this class, as
in Figs. 1M7, 164:8, of which the one makes the
groove, and the other the tongue, used for connecting
boards for partitions, 850., a
with the groove uucl lougue
joz'ul, Fig. 16449. There
are many other forms of
plane adapted to special
uses, an account of which,
includingmoulclz'ugpluues,
is given in the admirable
chapters on “ cutting
tools, ehisels, and planes,” ' '
in the Secmld Volume of Fig.1647. Fig.1648. Fig.1649,
Holtzapffel’s “Mechanical Manipulation,” to which
we are indebted for many of the details in this article.
We are anxious to devote a portion of our space to a
notice of a remarkable form of plane patented in
1844:, by Messrs. Silcock and Lowe, of Birmingham,
which has met with approval from practical men.
It is a (loulle fillz'sler plane, so constructed as to be
capable of filleting boards of all sizes, from about
58’- ths of an inch to about 3 inches, and may be
adapted to the several purposes of a fillelz'ug plane,
a sirle fillz'eler, a sue/t or duel: fillz'szfer and a s/rewecl
melee‘ pluue.
Fig. 1650 is a top view of the right side plane of
this double fillister, and Fig. 1652 a similar view of
the left side plane: Fig. 1651 is a side elevation of
Fig. 1650, and Fig. 1653 a side elevation of Fig. 1652.
These 2 planes, when joined together by the chase or
frame I’, form the complete tool. A1 A1 are the fore-
parts of the body of each plane, and A2 A2 the back
parts. H H are the pieces which connect the front
and back parts; Y1Y1 are the stocks, and Y2 Y2 the
handles. B B are the vertical cutters attached to the
front ends of the planes. x2 is a front view of one of


PLANE.
these cutters It is fixed in its place partly by a screw
0 passed through a cleft in the upper end of the cutter,
into the fore-end of the body of the plane, and partly
by a pin D, which projects from the fore—end, and fits
Fig. 1650.

Fjf'wfil


Fig. 1651.
into the cleft, the object of the pin D being to keep
the cutter perpendicular to the side of the plane, and
to prevent its being driven aside when in use. E E
are the horizontal cutters or irons, which are not se-
cured to their beds by wedges, but by screws, F F,
passed into the stock through clefts G e in the top-
ends of the irons. L is the mouth of the plane ; r is
a chase or frame projecting from, and attached at the
("B
U
A, o x1





Y {fix
to ‘in—J O
NEH
Fig. 1653.
inner end to the top of the forepart A1 of the body of
the right-hand plane, and slides into a recess R n on
the top of the forepart A1 of the body of the left-hand
plane, the outer edges of the chase B being bevelled
inwards, and the inner edges of the recess n bevelled
outwards.
The length to which this chase B is slid into the
recess 1R. regulates the distance between the two
planes, and this may be varied to suit boards of all
sizes between the limits already mentioned. The

planes are fixed at the required distance from each
other by means of a traversing small screw '1: attached
to the chase r, and in the recess n is a corresponding
hollow screw U: the screw it has a sliding cushion s,
by which it can be moved to and fro to any part of
the frame F, and the sides of the cushions are bevelled
to correspond with the bevelled inner edges of the
chase P. I is a fence, by which the distance between
the check or fillet and the front of the deal is regu-
lated. L2 is the inner-edge plate of the fence. K is
a chase or frame, similar to r, and projects from, and
is attached at the inner end to the bottom of the fore-
part of the left-hand plane, and M (shown separately
at x1 Fig. 1650) is a third chase, which projects from,
and is attached to, the outer edge of the fence I. The
chase M, sliding within the chase K, and the 2 chases
having for this purpose corresponding bevels at the
parts where they come in contact, the lower chase M
carries a fixed screw it, and the upper one a sliding nut
0, similar to the sliding cushion s, so that when the
fence has been adjusted to any required position, it
is secured by bringing the nut 0 over the screw N
and screwing up the one into the other. To regulate
the height to be given to the fillet, a stop, shown in
side and top views, Figs. 1654:, and 1655, is used.
The stem v of this
stop fits into a recess
W in the fore~end of
the body of the plane,
and by passing a
screw x through a


slot in the stem v v Fig-1654-
and the hole z, the “ a
stop is fixed at any l \ F
Fig. 1655.
required degree of
elevation, and the depth of the cut thus determined.
When this tool is used as a filleting plane both the
right and left-side planes are employed, fixed at a
distance from each other corresponding to the breadth
of the fillet. To use it as a side fillister, the left’side
plane, Figs. 1652 and 1653, is alone used, with the
stop inserted into the recess w. When used as a sash
or back fillister, the right-side plane, Figs. 1650 and
1651, is used, but with a slight modification in the
figure of the fence represented in the side and top
views, Figs. 1656 and 1657. To use the tool as a
skewed rabbet plane,
the right-hand plane,
with its chase r and -
the fence r, are laid

Hu—l
aside, and the left- Fig" 1656'
hand plane only em- m '
ployed. In this plane, I O
the stock, the handle,
and body of the fence,
Fig. 1657.
are of wood : the
screws FF, the cushion of the travelling-screw 'r, and
the sliding nut o, are all of brass. All the other parts
are of cast-iron, protected from corrosion by tinning
or zincing. The fore and back parts, A1 and A2, are
cast in one piece. The wood of the handle is not cut
across the grain as usual, but with the fibres running
PLANE—PLANING MACHINES.
4.23
in a direction at right angles with the body of the
plane, whereby a considerable increase of strength is
gained.
This patent also includes a dado-grooving plane, with
which upwards of sixteen difierent sizes of work may be




F29. 1658.
executed. Fig. 1658 is an elevation, and Fig. 1659 a
plan of this tool. AA2 are the front and back parts of
the body of the plane, which are connected together
by the bow-piece LB: 1) is a plate, cast in
the same piece with the body, the lower
edge of which forms the sole, and is
about ~t—th inch thick. E is the plane-




Fig. 1659.
iron, which is made at the upper end, and secured
in its seat both in the same way as the irons of the
double—fillister plane, and terminates at the cutting
edge in two projecting edges a a, which, when the
iron is ground and set up, act as side-cutters.
A 5,”; inch iron, adapted to this plane, is shown in
Fig. 1660, but the size may vary from %th inch to
55inch. r is a stop fence for regulating the depth
of the groove: it is
a \ fixed and shifted by
‘:5; means of an upright
Fig_1660_ arm r2, which shdes in
a groove in a project-
ing part of the fore-body of the plane, and a travers-
ing nut and screw G H. I is a side fence, the under
edge of which is all but flush with the sole of the
plane: it has 2 bevel-edged prongs b l, which pass
through a slot in the body of the plane, and by means
of a traversing nut L , inserted between these prongs
and a screw-pin K, the fence is fixed in its proper
working position, which is when it is in a right line
with the outer edge of the cutting-iron Fig. 1660.
M, the handle, is the only part of this tool which is
of wood. The materials and mode of putting to-
gether are the same as in the double fillister-plane.
This patent also includes a flitting or grooving-
ploagli, a try/ing plane, adapted for both rough and
fine work, and a moalcling or bead-plane.‘
The amount of time and labour required for planing

(l) A description of these, with illustrations, will be found in the
Meckanz'c’s B’Iagazz'ne, N o. 1096. It may be interesting to state
that the cabinet-makers of Birmingham, at one of their monthly
meetings, passed a resolution approving of Messrs. Silcock and
Lowe’s planes, “as a great improvement and advantage, and re
commend them to the trade as very useful and cheap articles.”

by hand has led to the introduction of PLAnIne
MACHINES. The first machine of this kind of which
we have any distinct notice, was patented by General
Bentham in 1791.2 It was based upon the action of
the ordinary plane, but was not much used. It ap-
pears, however, to have suggested the scale-board or
seabbarcl-plane, for cutting off the wide chips used for
making hat-boxes. The scale-board mac/zine used by
Messrs. Esdaile and Margrave at the City Saw-mills,
London, has a wide cast-iron slide plate, working
freely in chamfer bars raised on frame-work about 6
feet from the ground. Steam-power is applied to the
slide by means of a strap or 2 straps for the to-and-fro
motion. The slide is perforated for a cutter upwards
of 1 foot wide, placed beneath the slide, and inclined
horizontally about 40°, but the pitch of the iron, or
its vertical face, up which the shavings slide, has an
inclination of only 20°. The log of wood is used wet,
on account of its increased elasticity in that condition:
it is held down by weights, while the metallic plane
slides beneath it, and shaves off one clean shaving or
scale, the thickness of which is determined by the
adjustment of the cutter.
Mr. Bramah, in 1802, took out a patent for a
planing machine, in which the timber was passed
under a large horizontal wheel driven by steam-power
at the rate of 90 revolutions per minute. The face of
the wheel was armed with 28 gouges, placed horizon-
tally and in succession around it, the first gouge
being a little more distant from the centre and a little
more elevated than the second, and so on. The finish-
ing tools were 2 double irons.3
In Mr. Morris’s patent planing-machine for flooring-
boards, a rotatory adze roughly planes the bottom and
another acts on the top of the board: two oblique
fixed cutters next remove each a shaving of the full
length and width of the deal: two cutters make the
sides parallel, and 2 other grooves form the edges for
the tongues. The board enters the machine as it
comes from the saw-mill: it is driven forward by the
engine, and soon comes out in a condition fit for
fixing, or nearly so, for it may sometimes require a
little finishing with the hand smoothing plane in parts
where the grain is unfavourable to smooth cutting.4
Cutters with circular motion for producing mould-
ings and other works usually executed with hand-
planes are liable to some objections; there is a diffi-
culty in constructing and in sharpening them, and
although driven with great rapidity they leave marks
upon the work, because there is a distinct, though
small, interval of time between the passage of one

(2) See INTRODUCTORY ESSAY, page cxli.
(3) This machine is fully described in Nicholson’s “Architec-
tural Dictionary.” A remarkable feature in this machine was the
arrangement of the axis of the cutter-wheel. The bottom of this
axis was cylindrical to the extent of its vertical adjustment, and
was fitted in a. tube terminating in its upper part in a cupped
leather collar, impervious to oil or water, as in the hydrostatic
press. The injection of water into the tube by a small force -purnp
lengthened the column of fluid, on which the wheel was supported
as on a. solid post. By allowing a portion of the water to escape
by a valve, the descent of the wheel was readily efi‘ected.
(4) The cutting and moulding machines for wood used in the
erection of the Great Exhibition building are described in the
Inrnonccronx Essay, pp. xxxix to xiii.
4241
PLANOMETER.
cutting edge, and that next following; and during ‘
this interval, the advance of the work being unin-
terrupted, certain portions are less reduced than
others, and small hills and ridges are produced above
the general surface, which require to be smoothed
off by hand. In Messrs. Burnett and Poyer’s machine
revolving cutters have been rejected, and fixed cutters
employed. In planing mouldings they employ a stock
containing from 12 to 20 cutters, each figured and
secured by a separate wedge, so that the first cutter
penetrates but little into the moulding, and each
succeeding tool removes its own shaving; all the
cutters gradually assimilating more and more to the
last of the series, which is sharpened to the exact
form of the moulding. With such a machine, mould-
ings in pine wood can be worked at the surprising
rate of 70 lineal feet per minute, and the smoothness
is equal to that produced by the joiner’s hand planes
in the usual manner.
PLANOMETER. A name given to the trial or
surface plates by which certain flat parts in metallic
works are tested. The surfaces by which the sta-
tionary parts of framings are attached must be
tolerably true, or when screwed up they are liable to
bend and distort the machine; but very exact and
finished surfaces are required for the rectilinear slides
and moving parts of accurate machines for the valves
of steam engines, tables of printing presses, &o. The
machinist does not always attain this degree of ex-
cellence ; nevertheless for want of it there is great
waste in time, in steam power, in wear and tear, and
above all in skill misapplied.
For producing accurate work a true straight-edge,
and a true surface plate are indispensible. The file
and the scraper are the only instruments that should
be allowed in producing a truly flat surface: grinding
should be altogether excluded; since, in grinding
two surfaces together, one is very apt to become
convex and the other concave nearly to the same ex-
tent. There is also another objection to grinding;
some of the grinding powder is always absorbed by
the metal, and the metallic surfaces are thus con-
verted into laps, to the mutual injury of the slides
and works. Mr. Whitworth remarks that practically
the excellence of a surface consists in the number
and equal distribution of the bearing points; but
that if a ground surface be carefully examined the
bearing points will be generally found lying together
in irregular masses with extensive cavities interven-
ing. This arises from the unmanageable nature
of the process. The action of the grinding powder
being under no control, there are no means for
securing its equal diffusion or for modifying its appli-
cation with reference to the particular condition of
different parts of the surface. The practical result
of this is, that the mechanic neglects the proper use
of the file, knowing that grinding will follow to efface
all evidence either of care or neglect. If grinding be
discontinued, machines will improve in accuracy: the
surface plate and the scraping tool will then come
into use, and a new field be opened to the skill of the
mechanic. With a true surface plane he will, with a

little practice, find no difficulty in bringing up his work
to the required nicety.
The straight-edges used by smiths are usually of
steel; the edges may be acute, but are commonly of
some width, with a length of from '7 to 10 feet.
The width of the edge may vary from a}? to 71,- inch.
Cast-iron straight-edges from 6 to 9 feet long, the
widthuis 2 or 3 inches. In using the straight-edge
for testing a surface which is being corrected, it is
placed along the four margins of such surface, across
its two diagonals, and at various intermediate parts;
if the light cannot be seen between the edge and the
surface in any of these lines the surface is correct.
But this method alone is tedious, and not always
sufficient where great accuracy is required; a true
surface plane is therefore employed. It generally
consists of a plate of hard cast-iron, with ribs at the
back to prevent it from bending either from its own
weight, or from taking an unequal bearing on the
bench or other support. Mr. VVhitworth recommends
that the ribs be placed obliquely, and made to con_
verge to 3 points of hearing as in Fig. 1662, so that
the planometer may be supported on precisely the
same points notwithstanding the inequality of the
bench on which it rests; this can scarcely be the
case when the planometer rests on 4 feet or prominent
points at the corners as in Fig. 1661. The handles






/’f j j I
| , M5 ; '
l l ‘I .' I‘; 52 *-
“-"'= liiii
iii-ll llll
l
F198. 1661, 1662.
at the ends of Fig. 1662, are useful additions, allow-
ing the planometer to be inverted and applied to
heavy works which cannot be conveniently lifted.
Suppose it is required to produce a flat surface on
a piece of cast—iron. It is first chipped all over with
a chipping chisel and a hammer, in order to remove
the sand of the foundry mould, and the hard super~
ficial slain formed by contact with the moist sand.
[See CASTING AND Founnnve, page 345.] The rough
edges or ridges left by the chipping chisel are then
levelled with a coarse hand-file, especially those parts
which appear from the straight-edge to be too high.
When the rough errors have thus been corrected, the
work is removed from the vice, struck edgeways to
shake off loose filings, and inverted on the planometer.
But in order that this instrument may afi'ord practical
indications as to the parts of the work which first
require correction, the planometer is coated all over
with powdered red chalk mixed with oil, so that when
the work is placed upon it, the prominent parts, or
PLIASTERING.
4:25
those which require to be first removed, become
coloured. On first trial the work may rest only on
the two highest points; by a slight rubbing some
other high points may pick up some of the colour.
The work is then returned to the vice, and the file
applied chiefly at and about the coloured parts, the
straight-edge being occasionally used, and after some
time the planometer is again resorted to. It is now
probable that several points become coloured; these
are in like manner rubbed down, and by carefully
working in this way the number of points which are
coloured on applying the work to the planometer be-
come greatly increased. The smith’s plane may be
used in conjunction with the file, first with a grooved
cutter, and then with a straight~edge. The planing
and filing are alternated until patches of colour are
taken up from the planometer ; the scraper is then
used to complete the work. The scraper may be
made from a three-sided file carefully sharpened on a
Turkey stone, the sharpening being frequently re-
peated. If these processes be conducted with care
and judgment, and the work and the planometer
wiped clean, and both be rubbed hard together, the
high points of the work will be somewhat burnished,
and produce a finely mottled appearance. The plano-
meter should be evenly tinted with colour, and to-
wards the conclusion the quantity of red should be
only just sufficient to mark the summits of each little
elevation.
Thus it will be seen that the production of a flat
surface is a delicate operation, requiring care and
watchfulness on the part of the engineer. Far more
difficult is the originating the planometer itself, an
interesting description of which operation is given in
Holtzapffel’s “ Mechanical Manipulation,” vol. ii.1
At the meeting of the British Association held at
Glasgow in 1840, Mr. Whitworth exhibited surface
planes so true that when one was put upon the other
it floated until by its weight it excluded some of the
air, when the two adhered together with considerable
force.
PLASTER OF PARIS. See GYPSUM.
PLASTERING is the art of applying adhesive
plaster or cements to walls, ceilings, &c., for the
purpose of concealing the roughness of brickwork or
masonry, or the timber framing of partitions, floors,
roofs, and staircases; and also for allowing the appli—
cation of painting, paper-hanging, or other mode of
decoration. It is also the business of the plasterer
to form and fix ornamental cornices, centre pieces,
and other similar ornaments. Plastering does not
contribute to the stability of a structure, but adds
greatly to its neatness, elegance, and comfort. Its
general introduction is of comparatively recent date,
for we still find .in houses built only a century ago,
wainscoted walls, and boarded, or boarded and can-
vassed ceilings, or joists entirely uncovered.
In applying plaster to a brick wall, the surface
must be mode rough and prominent, in order that the
plaster may adhere properly. In building a new wall

(1) See also Smith’s Panorama of Science and Art.

which is to be plastered, the joints are left rough and
prominent instead of being drawn with the trowel, as
is done for exposed brickwork. In old walls, the
mortar must be removed to a small depth, as for
repointing, and the surface of the brickwork be
roughened by stubbing or pic/sing it over. The sur-
face is then brushed free from dust, wetted with
water, and the first coat of plaster applied in a fluid
state, with a coarse bristle brush; before this is quite
dry a coat of coarse plaster may be added. In
plastering upon quarter partitions, or on the under
surface of timber floors, an artificial surface is formed
for the plaster by nailing narrow slips of wood, named
lat/is, to the timber quarterings, or to the joists.
Laths are usually of fir, about 1 inch in width, and
from 3 to 5 feet in length, and they occur in three
thicknesses, viz. % of an inch, which is termed
single lat/i; -?,~ ths of an inch, or lat/i and a half; and
s of an inch, or double. They are formed by splitting
or pending, not only for economy of wood, but also for
roughness of surface, and greater strength and elasti-
city. They are nailed with cast~iron nails,1 trans-
versely across the joists, with a narrow slit or opening
between every two adjacent laths. It is sometimes
necessary to level the under surface of the joists, by
attaching slips of wood termed fie/"rings or firrings, so
that the laths may occupy one plane. The laths
should also be of uniform thickness, and made to
break joint as much as possible; but greater strength
is gained by making the ends of the continuous laths
meet upon a joist or quartering. The first coat of
plaster is called course stuj, and is a mortar of lime
and sand mixed with ox or horse hair, to give it con-
sistency; this is applied with a trowel in such a way
as to force the mortar into the narrow openings
between the laths, behind which it sets or hardens, in
the form of little swellings or lumps, and thus be-
comes keged, or secured to the laths very firmly. If
two coats only are to be applied to the laths, the
plastering is termed laid and set ,- the first coat, or
the laying, is levelled with the trowel, and when suffi-
ciently dry, its surface is scratched up or roughed
with a birch broom, and a thin coat or set of finer
plaster is laid on and smoothed with the trowel, with
occasional moistening with a bristle brush. The
first coat may also require to be sprinkled to promote
adhesion. In the better kind of work, where three
coats are applied, the first is laid on roughly, and
while soft is scored over with a pointed lath, with
cross lines 3 or 4'! inches apart, and as deep as they
can be made without laying bare the laths. These
lines enable the second coat to adhere more firmly.
The first coat may project i- or % the of an inch from
the laths, and is then called pricking—up. When it is
become firm by drying, ledges or margins of plaster
6 or 8 inches wide, termed sereeds, are formed at the
angles, and at intervals of a few feet across the sur-
face, and are adjusted to nearly the degree of projec-
tion or level of the finished surface, so as to form
guages for the rest of the work. The spaces or bays

(2) Oak-laths are occasionally used, and they must be secured
with wrought-iron nails.
4126
PLASTERING.
between the screeds are filled up flush with them, and
the plaster levelled by means of flat wooden floats,
(made with one or two handles, those with two handles
being termed derbys, or derlzyy‘loaz‘a) and sz‘mz'tr/izzf-
edges, or long pieces of wood planed to a straight-
edge. When the second coat is dry, it is swept over,
and a third coat of firze st‘zgfi or plaster made with
very fine white lime, is applied and well floatcd until
it forms a smooth hard surface. In applying plaster
to a brick or stone wall the first rough coat is termed
rendering instead of laying. Ceilings or fine surfaces
that are to be whitened or coloured, are finished
with a fine plaster, made of the best powdered lime,
well worked with water into a paste or patty, as it is
termed. For surfaces that are to be papered, a stud
a little less fine, mixed with a small proportion of hair,
is used. Surfaces intended for painting, are finished
or set with cam/‘arc? stacco, consisting of two-thirds
ordinary fine stuff without hair, and one-third very
fine clean sand; the last coat is finished with the
trowel without the float.
The plasterer is attended by a labourer to supply
his boards with mortar, and a boy on the scaffold to
feed his karat. This is a piece of wood 10 inches
square, held by a projecting handle at the bottom,
and is adapted to the reception of a small quantity of
mortar. The laying-on trowel is a thin plate of
hardened iron or steel, 10 inches long, and 2%; wide,
rounded at one end, and square at the other end or
heel. It is very slightly convex on the face. About
the middle of the back the spindle or handle is riveted
in at right angles, and this returning in the direction
of the heel, parallel to the tool, fits into a rounded
wooden handle, by which the workman grasps it.
When not in use, this tool must be kept perfectly
clean and dry, for if a spot of rust were to form on
it, it would stain some of the delicate plasters with
which it is used.
The construction of cornices is also the work of
the plasterer. Cornices may be plain or ornamented,
or both. If they project more than 7 or 8 inches,
trackers or pieces of wood must be fixed at distances
of 11 or 12 inches all round the site of the intended
cornice, and laths be nailed to them: the whole is
then covered with a coat of plaster. A beech mould
is made by the carpenter with the profile of the in-
tended cornice: the mould is about :fi- inch thick with
the quirks or small sinkings of brass. The plasterer
must remove all sharp edges, and open with his knife
the points which will not receive the plaster freely.
The cornice is then run by 2 workmen, who are pro-
vided with a tub of putty and a supply of plaster-of-
Paris. Before using the mould they gage a screed
upon the wall and ceiling of putty and plaster, cover-
ing so much of each as will correspond with the top
and bottom of the intended cornice. On this screed
are nailed one or two slight deal straight-edges,
adapted to as many notches or chases made in the
mould for it to work upon. The putty is mixed with
about one-third plaster-of-Paris, andbrought to a semi-
fluid state with water. With 2 or 3 trowelfulls of
this composition upon his izaw/a, which he holds in

his left hand, he begins with his trowel to plaster
over the surface intended for the cornice, while his
partner applies the mould to see where more or less
is wanted. When a sufficient quantity of plaster has
been laid on, the mould is held steadily and firmly to
the ceiling and wall, and moved backwards and for-
wards, the effect of which is to remove the superfluous
stuff and leave an exact impression of the mould upon
the plaster. In the course of this operation the other
workman fills up any deficiencies that may occur with
fresh plaster. In this way the work is executed with
rapidity; the plaster is sprinkled from time to time
with water during the progress of the work, to prevent
it from setting too quickly. To secure the correct-
ness of the cornice it is desirable to finish all lengths
or pieces between any two breaks or projections at
one time. Cornices of large proportions may require
3 or 4: moulds. Internal and external mitres, and
small returns or breaks, are modelled and filled up by
hand at a subsequent operation. When cornices are
to be charged with ornaments, certain projections are
made in running the mould, so as to leave a groove
or indentation in the cornice into which the ornament
is laid, and secured in its place by plaster—of—I’aris.
These ornaments are cast in plaster-of-Paris from clay
models, but of late years other substances, lighter and
less liable to injury than plaster, have been used, such
as caroer’s compo, consisting of a mixture of whiting,
resin, and glue; papz'er maciw’, with a priming of
whiting and glue over it, when sharp impressions are
required; carton jaz'erre, with layers of whiting and
glue; and garter percka. One of the advantages of
carver’s compo is, that not being brittle, ornaments
can be bent about and adjusted while being fixed, or
after they are fixed.
Plasterers’ work is measured in feet and inches,
and charged by the superficial yard of 9 square feet,
according to its quality. Special charges are made
for arrises or external angles, quirks, mouldings, and
other enrichments and carved work.
Such are the details of the plasterer’s art in Eng—
land, where materials for lime are abundant, but
where the means for making plaster, properly so
called, are limited. In other words, this country
possesses abundance of carbonate, but very little
sulphate of lime; plenty of chalk and limestone, but
not much gypsum. In the neighbourhood of Paris,
on the contrary, where gypsum is abundant, and is
extensively burnt into plaster-of-I’aris,1 the art of the
plasterer varies with his material. The coarser kinds
of plaster are used for ordinary work, such as walls
and partitions; the finer kinds being used for ceilings,

(1) As the plaster is apt to become discoloured when the gyp-
sum is burnt with ordinary fuel, an improved method of preparing
the plaster has been suggested. It is founded on the fact, that
high—pressure steam, like gases at a high temperature, greedily
absorbs water from any bodies with which it maybe in contact.
A jet of steam raised to upwards of 400° Fahia, is projected upon
the gypsum broken into small lumps, when it takes up all the
water, and leaves the plaster in the state of a pure anhydrous
sulphate of lime. The difliculty of the process consists inmaking
the chamber and machinery strong enough to resist the action of
the high-pressure steam without too great an outlay.
PLATING—PLATINUM.
4'27
cornices, &c. For walls, the plaster must be gaged
stiff for the first coats, and more fluid for the setting
coat. For cornices worked out in the solid, the core
is of stiffly-gaged plaster: this is floated with finer
material and finished off with plaster of about the
consistence of cream. Walls are first jointed and wet-
ted with a broom : a coat of thinly-gaged stuff is laid
on with a broom, or worked roughly with a trowel.
The next coat is gaged stiff, laid on with a trowel,
and floated with a rule, but the face is finished with
a hand-trowel. The rapidity with which the plaster
sets does not allow the surfaces to be so even, or the
angles so sharp and true as with us. The rapid dry-
ing is however a great advantage. Walls of this kind
are not capable of resisting the action of water.
Plaster has much less tenacity than mortar, the one
decreasing, and the other increasing with time.
New walls, or walls in damp places, are apt to
generate nitrate of potash, which works its way to
the surface, where it effloresces and carries off the paint
in large patches. The workmen call this the snllpezfre
rot or sallpelering. It is not, however, pure saltpetre,
for nitrate of soda and chloride of potassium are also
found with it. This effect, which is not easily ex-
plained, will be further noticed under POTASSIUM.
PLATE-GLASS. See GLAss, Sect. viii.
PLATING is the art of producing works in an
inferior metal covered with a film of silver, so as to
have the appearance of being made of the precious
metal. The application of thin leaves of silver to
finished brass articles appears to have been the origi-
nal method of plating, and was long known as Franc/z
plating. Articles in steel, such as dessert-knives, were
also plated in this manner. A piece of silver leaf was
placed on each side of the blade sufiicient to cover it,
and the knife was then introduced into a furnace
until the union of the two metals was effected. The
knife was then finished by burnishing. With brass
goods the surface was made chemically clean, and the
part to be plated was heated to a point just below
that at which the metal changes colour; silver leaf
was then laid on, and the adhesion produced by bur-
nishing, a fine polish being produced by the latter
process. It is worthy of remark, that the old method
of coating articles made of an inferior metal with a
superior metal, is now again adopted, under the
guidance of the refined and elegant principles of
electric science. See the section on ELECTRO-PLATING
under the article ELECTRO-METALLUHGY.
The goods produced by the old method were not
found to be very permanent. A better plan was
therefore resorted to, and which is still practised at
Sheffield, Birmingham, and elsewhere. In this pro-
cess the metal is first produced in sheets plated on
one or both sides, and the goods are manufactured
from these sheets. An ingot of alloy of copper and
brass is cast about 1%— inch thick, 3 inches broad, and
18 inches long. This ingot must be free from holes
and flaws : it is cast in an iron mould furnished with
rising mouth-pieces, to give a certain amount of pres-
sure to the metal, and to allow impurities to rise above
the general surface. The face of the ingot is carefully

dressed with a file on one side for what is termed
single plating, and 6n both sides for clan/He plating.
A thickness of silver is then laid upon the copper,
equal in weight to about glzth or 516th of that of the
copper, and for double plating about faith or 315th;
the proportional thickness of the two metals varying
in the single plating from Y§§th to 116th. The plate
of silver is out rather smaller than the ingot, and is
accurately tied to it with iron wire, after which a
little saturated solution of borax is brushed in at the
edges. The ingot is now ready for the plating fur—
nace. This is heated with coke, put upon a grate at
a level with the bottom of the door. The latter has
a peep-hole in it, through which the workman watches
the operation. The ingot is placed upon the coke;
the water of the solution of borax speedily evaporates,
and the borax itself fuses and excludes the air from
under the silver, for this might oxidise the copper
and prevent adhesion. The proper temperature of
the ingot is indicated by the silver being drawn into
contact with the copper, and the moment the man
perceives this to have taken place he removes the bar
from the furnace, for if left longer the silver would
become alloyed with copper, and the plating be
spoiled. The operation is complete when a film of
silver solder is formed at the surfaces of contact.
The ingot is next cleaned, and then rolled out into
sheets of the proper thinness between cylinders, with
frequent annealing during the process. After the
last annealing, the sheets are immersed in hot dilute
sulphuric acid, and scoured with fine Calais sand:
they are then ready to be formed into the large
variety of articles which are produced by raising
with the hammer; by spinning in the lathe; by stamp-
ing, aliasing, &c. ; and as these processes are adopted
in fashioning any of the malleable metals, we must
refer our notice of them to the article RAISED Wonxs
IN METAL.
The plated copper-wire used for making bread-
baskets, toast-racks, snuffers, &c., is produced in the
following manner. The silver is first formed into a
tube, with one long edge projecting over the other,
and a red-hot copper rod being inserted into this tube,
the edges of the silver are made to unite by the pres-
sure of a steel burnisher. The silver tube being thus
completed, is cleaned inside, and put upon the copper
rod which is to be covered, and which it exactly fits.
This rod is somewhat longer than its silver coating,
and being grooved at the extremities of the silver,
the silver edges are worked into the grooves in order
to exclude the air from the covered part. The rod
is then heated to redness, and rubbed briskly over
with the steel burnisher lengthways, so as to unite
the two metals firmly into a solid rod, which is now
ready for drawing into wire of the required form and
fineness.
PLATINUM (Pt 99), the heaviest of all known
substances, its specific gravity being about 21. This
metal was not brought into Europe until the middle
of the last century, although it had long been known
in America under the name of plaz‘ina, which signifies,
in Spanish, little silver; but it was of very little value
{0'28
PLATINUM.
on account of the great diificulty of working it. Pla-
tinum occurs in Brazil pure and native, mixed only
with palladium. It also occurs in combination with
a variety of substances, such as palladium, rhodium,
iridium, osmium, ruthenium, iron, copper, and lead,
and sometimes with silver ;-—mixed also with grains
of osmium-iridium, gold, titaniferous iron, chrome-
iron—ore, hyacinth, spinelle, and quartz ; and with gold
amalgam, which remains behind after the extraction
of the gold by mercury. All these substances are
found in different varieties of what is called crude
platinum-ore, or crude platina, or plazfz'zzzferous sand.
The latter is found chiefly in rivers and alluvial depo-
sits in various parts of South America; on the west-
ern declivity of the Ural Mountains in Russia; also
in Borneo and other places. Indeed, it appears to be
much more widely distributed than was formerly sup-
posed. Grude platinum occurs in small flattened
grains of a greyish-white colour, resembling tarnished
steel: they vary in size from that of linseed to that
of hempseed, but larger fragments have been dis-
covered. The complicated nature of the ore renders
the chemical treatment also complicated,1 but the
general process is as follows :——The crude metal is
acted upon, as far as possible, by nitro-hydrochloric
acid; a deep yellowish red and highly acid solution
is produced, and to this is added sal-ammoniac, which
throws down nearly the whole of the platinum in the
state of ammonio-chloride. This is well washed with
cold water, dried and heated gently in a black—lead
crucible, just sufficient to expel the sal-ammoniac, so
that the spongy platinum may be left in a loose state.
It is gently rubbed to powder between the hands,
pressed through a linen bag, and the coarser particles
which remain in the bag are triturated in a wooden
mortar with a wooden pestle. No harder substance
must be used, or the powder will acquire metallic
lustre, and the particles will not weld properly toge-
ther. The powder is lastly triturated with water, and
the finer particles are separated from the coarser by
elutriation. The whole of the fine powder is then
mixed up with water to a uniform paste, and pressed
into a brass cylinder 6% inches high, 1'12 inch in
diameter at top, and 1'23 at bottom: its lower and
wider end is accurately closed with a steel stopper,
which enters it to the depth of % inch, and is wrapped
round with bibulous paper, by which the running off
of the water is facilitated. The interior of the cylin-
der is smeared with grease, and the cylinder being
placed in a glassfull of water, is itself filled with
water, and then completely filled with the platinum
paste. In this manner all cavities and inequalities
are avoided. On the platinum paste is laid, first, a
piece of blotting-paper, then a layer of woollen cloth,
and part of the water is pressed out of it by means of
a wooden cylinder held in the hand. A plate of cop-
per is then laid upon the paste, so that the cylinder
may be introduced in a horizontal position into a very

(1) The reader interested in the subject is referred to the trans-
lation of the sixth volume of Gmelin’s “Hand-book of Chemis-
try,” published in 1852 by the Cavendish Society, for the fullest
notice of platinum that we are acquainted with.

powerful lever-press, Fig. 1663. It consists of a flat
iron bar, set edgeways, and screwed down by a hook
E near its middle, where it would otherwise be liable
to bend, to a strong wooden bench c :o. The bar is
connected by a pivot at its extremity A with the lever
A r e. An iron rod, r n, which turns at its two ex-
tremities upon the pivots r and H, proceeds from the
lever at F, and as the lever descends, propels forward
the carriage I, which slides along the bar. A stopper
or block being placed in the vacant space 11:, the
carriage communicates motion to the cradle 15 Z m,

D "j "
\ Fig. 1663. ‘l
l
which is also made to slide along the bar, and carries
the barrel N, which lies upon the cradle, straight-
forward against the piston 0, which rests by its end
against r, a projection in the further extremity of the
bar. After compression, which is to be carried as
far as possible, the stopper at the extremity being
taken out, the cake of platina will easily be removed
on account of the conical form of the barrel. The cake
is now hard enough to bear handling without break-
ing: it is placed upon a charcoal fire, and heated to
redness, in order to drive off moisture, burn off grease,
and promote cohesion. The cake is then heated in a
wind furnace, for which purpose it is raised upon an
earthen stand about 2%- inches above the grate, the
stand being covered with clean quartzose sand, on
which the cake is placed on one end. It is then
covered with an inverted cylindrical pot of the most
refractory crucible ware, and the furnace is raised to
its most intense heat, in order to drive off all impu-
rities and prevent the platinum from blistering, which
is its usual defect in its manufactured state. The
furnace is fed with coke, and the action continued for
about 20 minutes from the time of lighting it, a
breathing heat being maintained for the last 4: or 5
minutes. The cake is then removed, placed upright
on an anvil, and struck while hot on the top with
a heavy hammer so as to close the metal. If the
metal becomes bent in the hammering, it must not
be hammered on the side, or it will crack : it must be
straightened by blows on the extremities, directed so
as to reduce to a straight line the parts which project.
The ingot, thus formed, may now be forged into the
required form like any other metal. After forging, it
may be cleaned from ferruginous scales by smearing
over it a moistened mixture of equal parts, by measure,
of crystallized borax and salt of tartar; which, when
in fusion, form a ready solvent for such impurities; and
then exposing it on a platinum tray, under an inverted
pot, to the heat of a wind furnace. The ingot, in
PLATINUMT—PLINTHIPLUMBIN G.
429
being taken out of the furnace, is to be immediately
plunged into dilute sulphuric acid, which in a few
hours will entirely dissolve the flux adhering to the
surface. The ingot may then be flattened into leaf,
drawn into wire, or submitted to any of the processes
of which the most ductile metals are capable. The
sp. gr. of the metal thus prepared, drawn into fine
wire from a button which had been completely fused
with an oxyhydrogen blowpipe, was found to be 2116.
The aggregate sp. gr. of the cake of metallic mud
when first introduced into the barrel, exclusive of
moisture, is about 453: when taken out from the
press it is about 10 : that of the cake fully contracted
on being taken out of the wind furnace before forging,
is from 17 to 17 '7 . The mean sp. gr. of the plati~
nuin, after forging, is about 2125, although that of
some rods, after being drawn, is 214; but that of fine
platinum wire is 215, the maximum specific gravity.
The mean tenacity, determined by the weights required
to break them, of 2 fine platinum wires, one of 3,100,
the other of fi‘fith of an inch in diameter, reduced
to the standard of a wire Tlfith inch in diameter, was
409 lbs. The mean tenacity of 11 wires, beginning
with 131-01, and ending with wl-o-Eth of an inch, re-
duced to the former standard, was 589 lbs. ; the
maximum being 645, and the minimum 4:801bs.1
Platinum, united in compact masses, is harder than
copper, but softer than iron. It exceeds in tenacity
all the metals except iron and copper. Next to gold
and silver, it is the most ductile of the metals, and
may be drawn out into wires fill-6th inch in diameter,
but when enclosed within a silver wire it may be
reduced to filmth and even to moth of an inch in
thickness, but in the latter case the wire is not co-
herent in long pieces. Platinum may be beaten out
into very thin laminae, like gold-leaf. A small pro-
portion of iridium makes it harder and less ductile.
Platinum may be welded at a white heat: indeed, it
is on this valuable property that Wollaston’s process
of rendering platinum malleable is founded. It does
not fuse in the strongest heat of a forge; but if in
contact with the fuel, a fusible alloy of silicium and
platinum is formed. Platinum resists oxidation in
the air at a red heat, as well as gold and silver, and
is much harder and more difficult of fusion than those
metals: it is not attacked either by sulphur or by
mercury: it does not dissolve in any simple acid, so
that nitric acid and sulphuric acid may be boiled in
it; it dissolves in aqua regia, but less readily than
gold. These properties cause platinum to be pecu-
liarly adapted as a material for making chemical
vessels. Stills of platinum are now commonly used
in sulphuric acid works.1 The metals and the oxides
of easily fusible metals, must not be fused in vessels of
platinum, for they will form alloys with it; platinum
is attacked by the caustic alkalies at a red heat, but

(l) Philosophical Transactions for 1829.,
(2) In the Great Exhibition, M. Quennessen exhibited a pla-
tinum alembic for sulphuric acid, of the capacity of 250 pints,
made in one piece, without seam or solder. The price, we believe,
exceeded £800, a sum which is not unfrequently paid for a large
platinum vessel.

not by the alkaline carbonates. When platinum is
heated in presence of arsenic, phosphorus, and some
other bodies, it loses its malleability and ductility.
A mixture of silica and carbon produces a similar
effect, as already noticed; hence platinum vessels
should not be exposed to the direct action of fuel,
but be encased in an earthen crucible containing a
little magnesia and caustic lime.
Platinum exists in two states of minute division,
viz. sponggplutinum, in which the metal is in its crys~
talline state; and platinum blue/c, which is amorphous.
Spongy platinum is obtained by igniting the ammo-
nio-chloride of platinum, as in Wollaston’s process
already noticed. The remarkable property of this
metal in determining the union of oxygen and hydrogen
gases has been noticed under HYDROGEN, in describ-
ing the Dtibereiner lamp, Fig. 1189. This property is
exerted still more energetically by platinum black, in
which the metal is in a more minutely divided state
than in the sponge. It is prepared by boiling a solu-
tion of chloride of platinum, to which an excess of
carbonate of soda and a quantity of sugar have been
added, until the precipitate formed after a short time
becomes quite black, and the supernatant liquid
colourless. The black powder is collected on a filter,
washed, and dried by a gentle heat. This substance
has the property of condensing gases into its pores,
especially oxygen, and it is constantly employed in
the laboratory in eudiometrical experiments for ex-
ploding the mixed gases :3 when placed in contact
with a solution of formic acid it converts it into
carbonic acid with abundant eifervescence: alcohol
and ether, dropped upon platinum black, become oxi-
dised, and form acetic acid: indeed, one of the me-
thods of forming vinegar from alcohol is founded on
this property. See AoE'rIC ACID.
Platinum forms two compounds with oxygen, PtO
and PtOz: there are also two chlorides, PtCl and
PtOlg. For an account of these and other compounds,
we must refer to works on scientific chemistry.
PLINTH, from whiz/dos, a brick; a flat, square
tile, sometimes also called the slipper, used as the
foot or foundation of columns under the mouldings
of the base and pedestal. It is also named orle or
orlo. The plint/i of a statue is a base or stand, and
may be flat, round, or square. The plint/i of a wall
is a term applied to two or three rows of bricks ad-
vancing out from the wall; or, in general, for any flat
high moulding, serving in a front wall to mark the
floors, or to sustain the eaves of a wall and the lamier
of a chimney.
PLOT’l‘INGis the art of describing or laying down
on paper, the several angles and lines of a tract of
ground surveyed by a theodolite and a chain. See
SURVEYING.
PLUMBAGO. See BLACK-LEAD.
PLUMBING. The business of the plumber is to
cover roofs and flats with sheet-lead, to lay gutters,
to cover hips, ridges, and valleys, to fix water-trunks,

(3) A very full notice of the action of platinum in various
forms upon gases, is given in the second volume of Gmel'm’s
Handbook.
430
PLUMBING.
to construct cisterns and reservoirs, to lay on the
requisite pipes and cooks to them, to fix water—closet
apparatus, and to erect pumps, &c.
In covering terraces or flats with sheet-lead, a
thickness or weight of Slbs. to the foot should be
used. A level bottom must be first laid of plaster or
of boards; the latter of sufficient substance to pre-
vent warping, or the lead will be uneven and liable to
crack. As the sheets of lead do not exceed 6 feet in
breadth, and, if cast, 16 or 18 feet in length, and if
milled, 25 feet in length, water-tight joints are re-
quired in covering large surfaces. They are made by
forming laps or rolls. A roll is a strip of wood 3,
Fig. 1664:, about 2 inches square, rounded on its upper
side, nailed under the joint of the sheets where the


Fig. 1664.
edges overlap : one of these edges is dressed up over
the roll on the inside, and the other is dressed over
them both on the outside, by which means the water
cannot penetrate. No fastening is required; the
hammering of the sheets together down upon the flat
being sufficient. When rolls cannot be used, seams
must be resorted to: the approximate edges of the
lead are bent up over against each other, and dressed
down close to the flat throughout their length. This
is not equal to the roll-joint: but the joints may be
secured by soldering, which, however, is not advisable,
since the variations in temperature cause the lead to
crack. Indeed, it may be taken as a general rule,
that solder should not be used unless absolutely
necessary. Leaden flats and gutters should be always
laid with a fall or current, as it is called, to keep them
dry. The fall is usually made from back to front, or
in the direction of the length of the sheet: 71- of an
inch to the foot is a snflicient inclination, and this is
provided for by the carpenter while preparing the
ground or platform on which the lead is to be laid.
For hips and ridges, lead of 6 lbs. to the foot is suffi-
ciently thick.
In making gutters, &c. pieces of milled lead, called
flas/zz'ngs, r, Fig. 1665, about 8 or 9 inches wide, and


Fig. 1665.


5 lbs. to the foot, are fixed in the walls all round the
edges of the sheet-lead with which the flat is covered,
and sufiicient to hang down over them to prevent
the wet from entering the interstices between the
raised edge and the wall. The mortar is raked out
of the joint of the bricks next above the edge of the
sheet, and the flashings are inserted into the crack at
the, upper sides, and their lower edges are dressed
over those of the lead in the flat or gutter. Or the
flashings may be fastened with wall-hooks, and their

lower edges dressed down. In Fig. 1665, an is the
gutter-board, E r the eaves-board, and re the foot of
the eaves course.
Drlps in flats or gutters are formed by raising one
part above another, and dressing the lead in the man-
ner described for covering the rolls. They are re-
sorted to when the gutter or flat exceeds the length
of the sheet, and they render soldering unnecessary.
Cisterns are usually of wood or masonry on the
outside, lined with sheet-lead, and soldered at the
joints. Water-trunks and pipes are made of a spe-
cified number of pounds weight to the yard in length.
They are fitted with large case fieads above to receive
water from gutter spouts, and with 8/1068 to deliver
the water below. They are attached to the walls of
buildings with flanches of lead, and secured by means
of spike nails. Iron hold-fasts are used for attaching
and supporting service and waste-pipes. See PUMP.
From the nature of his material the plumber re-
quires but few tools. He has a hammer, wooden
mallets of different sizes, and a dressing and flatz‘z'rzg
tool. This last is of beech, about 18 inches long and
2% inches square, placed smooth and fiat 011 the under
surface, rounded on the upper, and one of its ends
tapered off round as a handle. With this tool the
plumber stretches out and flattens the sheet-lead, or
dresses it to the shape required, using first the flat
side, and then the round one, as occasion may require.
The plumber also uses a jacls and a trgz'ag plane, for
reducing the edges of sheet-lead to a straight line.
His cutting tools are c/zz'sels, gauges, and Mines, the
last for cutting the sheet-lead into slips and pieces
after it has been marked out by the chalk line. He
also uses files and the usual apparatus for soldering.
Plumber’s work is usually estimated by the cwt.
of 112 lbs. : but some articles are taken by the pound
weight, by number, and even by size. The prices of
the various articles, from sheets of lead and pipes, to
the cooks, bosses, ferules, valves, balls, traps, &c.,
being taken at their wholesale prices, an addition of 30
per cent. will usually repay the tradesman for ordi-
nary expenses and profit, with the exception of car-
riage. It is stated, however, that plumbers often
charge for sheet-lead and labour at so much per cwt.;
for pipe of a certain bore at so much per foot ; for so
many joints in pipe of such a size, that is, for the
labour and solder consumed and expended in making
them; the account winding up at length with a sepa-
rate charge for solder or for labour. This is actually
charging twice over. Such being the “ custom of the
trade,” as it is termed, the law courts have sanctioned
these improper charges; but, as Professor Hosking
properly observes, “ the now prevalent custom of
artificers’ work being done by general builders by
tender and contract, has considerably lessened the
injury to the public from this abuse, and proved it to
be really so by the moderate profits the same men will
content themselves with if they make a tender. who
would persist in charging at the old rate if they were
instructed to do the work without being bound by
a contract?"
(1) Encyclopaedia Britannica, article Building.

PONTOON—POROSITY.
431
PLUSH. A textile fabric, with a sort of velvet
nap or shag on one side. See Wnavnve.
POINT NET. A style of lace formerly much in
fashion, but now superseded by the bobbin net manu-
facture. See the section Lace, in the article WEAVING.
POLISHING. See GRINDING AND POLISHING.
PONTOON. A barge or flat-bottomed boat, used
in the formation of floating bridges for military pur-
poses.
Bridges consisting of timber platforms supported
on floating vessels, are of great antiquity; and they
have at all times occupied much of the attention of
military engineers. One of the latest forms of pon-
toon is that by Colonel Pasley: it is in the form of a
canoe, with decks, and is 22 feet long, and with a
breadth and depth of 2 feet 8 inches. One end is
shaped like the head of a boat, in order that it may
be moved through the water, by rowing, with either
end foremost: it is constructed of light timber frame,
covered with sheet copper, except the deck. Each
vessel is formed in two equal parts by transverse
partitions, so that the demi-pontoons may be separated
from each other when the bridge is to be conveyed
on carriages by land with the army. In the water
the parts are connected together by a rope, which
passes through two perforations in the keel near the
point of junction, and by a rectangular frame of wood
attached along the deck by lashings. Each half
vessel is also divided into two compartments by a
partition. Small pumps are provided, by means of
which the pontoons may for a time be kept afloat
should a hole be made in the side by a shot or other
accident.
Cylindrical pontoons of tin, 22 feet long and 2%.;
feet in diameter, invented by Colonel Blanchard, have
been introduced into the service. These have hemi-
spherical ends, and are divided longitudinally and trans-
versely into several compartments by tin partitions,
to increase their strength and to prevent them from
sinking if perforated in any part. These pontoons are
light and buoyant, but are said to be less durable
than Pasley’s copper pontoons, and more liable to
injury when transported by land.
The method of forming a bridge is nearly the same
with either kind of pontoon. A rectangular frame,
the length of which is about equal to the breadth of
the platform of the intended‘ bridge, viz. 12 feet, is
laid down longitudinally on the deck of the canoe,
or on the surface of the cylinder, and is kept in its
place by rope lashings. On the upper surface of his
frame, in the direction of its breadth, are nailed pieces
of wood, in pairs, at equal intervals; the distance
between every two in each pair being little more than
equal to the breadth of abaulk or joist (2% inches),
one extremity of which is to be received between them,
and the number of pairs being equal to the number
of baulks which are to support the dresses or planks
forming the roadway. A raft is formed with two of
these pontoons by placing them parallel to each other
at a distance from centre to centre equal to about 12%
feet; the ends of two bulks or zfmnsoms are made to
rest upon the frames, the distance between them

being equal to the intended breadth of the bridge;
and they are kept steady by having near each extremity
a hole bored through them, into which enters an iron
pin fixed vertically in the frame ; they are also made
fast to the pontoon by ropes passing through rings
on the decks. Three or more baulks are then laid
down parallel to the transoms, with their extremities
confined between the cross-pieces nailed to the frames :
the chesses are laid close together above them, and
their ends are kept down by ribands attached to the
transoms by lashings passing over them, and under
the latter at intervals. Itowlock pins are fixed in the
ribands, and when the bridge is not formed, the ribands
being then parallel to the lengths of the pontoons,
at the sides of the raft, the latter may be moved on
the water by cars. In forming the bridge a certain
number of such rafts are rowed to their stations in a
line across the river, and anchored with the lengths
of the pontoons parallel to the banks ; the distances
between the nearest pontoons in two rafts being
equal to that between the two pontoons in each raft.
Each raft, then, carrying the materials for construct-
ing a platform over the water between itself and the
next, is laid down in a manner similar to that for
laying down the platform of the raft, and from each of
the extreme pontoons a similar platform is extended
to the shore of the river.
Under favourable circumstances, the complement
of men attached to each raft of two pontoons, viz. 1
non-commissioned ofiicer and 6 privates, can dis-
mount two vessels and their, stores from the carriages,
launch them, and form the raft in a quarter of an hour.
All the rafts being put together at the same time, the
whole bridge may be formed in another 7}; of an
hour. When the passage has been effected, the bridge
can be dismantled in eight minutes; the rafts can
then be taken to pieces and the vessels and stores
repacked on the carriages in i of an hour. A cart
with 2 wheels may be used for conveying each pon~
toon; the latter is separated into 2 demi-pontoons,
which are placed side by side above their stores.ll
Details of military operations do not enter into the
plan of this work; but we 'give the above as an ex-
ample of successful bridge engineering. The various
forms of boat bridges, bridges on rafts of timber,
casks, &c., are detailed in the work of Sir Howard
Douglas on Military Bridges. Second Edition, 1832.
POPLAR. See Woon.
POPPY. See OPIUM.
POB CELAIN. See Porrnnx and PORCELAIN.
POROSITY. The minute particles of which a body
consists are so arranged as to leave certain intervals
or spaces between them. This arrangement is termed
porosity, and the spaces themselves are named pores.
In some cases, as in sponge and cork, they are large
enough to be seen by the unassisted eye, in others
they require the aid of a microscope. Their visibility

(1) A lithographed pamphlet of 70 pages 8vo. was prepared in
1823, entitled, “ Exercise of the New-decked Pontoons or Double
Canoes, invented by Lieut.-Colonel Pasley, RE. Lithographed
at the Establishment of Field Instruction, Royal Engineers’
Department, Chatham.”
4:32
PORPHYRY—POT-METAL—POTASSIUM.
by either means is not, however, necessary to prove
their existence. All bodies, even the most compact,
may be diminished in bulk, either by mechanical force
or by reduction of temperature, which could not be
the case if the particles were actually in contact, or
so aggregated as to leave no interstitial spaces. When,
therefore, a body expands, the distance of its particles
from each other is increased, and conversely, when a
body contracts or diminishes in bulk, its particles
approach each other. The porosity of bodies is also
inferred from their elasticity. Liquids also appear to
be porous. When salt is dissolved in water, the
volume of the mixture is less than the sum of the
volumes of the substances when separate. The par-
ticles of the salt appear to introduce themselves
between the particles of the water. Alcohol and
water furnish another example of this apparent pene-
tration of matter. The porosity of matter is taken
advantage of in the purification of liquids by filtra-
tion; paper, solid stone, sand, &c., being used for the
purpose. See FILTRATION.
PORPHYRY. In the short classification of the
granites, given in the INTRODUCTORY ESSAY, page
lxxix., granite, with distinct additional crystals of
felspar, is termed porp/zyrz'éz'c granite. The term
porp/zyry is usually applied to felspar containing im-
bedded crystals of the same substance. The methods
of working it for ornamental purposes are noticed
under GRANITE. For its application to the making
of slabs, mullers, and mortars, see TRITURATION.
PORTER. See BEER.
PORTLAND STONE, a fine compact oolite,
named from the island where it is quarried. See
SToNn.
POSTS, KING and QUEEN.
Figs. 511, 512.
POT-METAL, an alloy of copper and lead. Ordi-
nary pot-metal, 6 oz. of lead to every pound of copper,
is called dry pownetal, because this proportion of
lead is taken up without separating on cooling. It is
brittle when warmed. The proportion of 8 oz. of
lead produces an inferior pot-metal, named wet p01.‘-
metal, because the lead oozes out on cooling. This is
especially the case when new metals are used, hence
it is customary to fill the crucible with old metal and
make up the required quantity with new. This alloy
becomes very brittle on a slight application of heat.
The addition of tin improves pot-metal; but if the
tin be in excess, the alloy resembles gun-metal. A
small proportion of zinc may be added, but with this
metal, the tendency is for the copper to combine with
it to form brass to the exclusion of the lead. Anti—
mony assists the combination of the constituents of
pot-metal. Mr. Holtzapfl'el states that 7 lead, 1 anti-
mony, and 16 copper mix well at the first fusion, and
form apparently a superior metal to ll lead and 16
copper.
POTASH. See POTASSIUM.
POTASSIUM (IMO), the metallic base of the al-
kali potash, a substance widely diffused in nature,
but always in combination with other bodies. Many
of the minerals which compose the crystalline rocks,
See GABPENTRY,

such as the felspars, micas, &c., contain silicate of
potash. As these rocks crumble down into soils, the
potash assumes a soluble form, and is gradually taken
up by plants, and accumulated in their substance in
conjunction with organic acids: thus potash in the
vine is combined with tartaric acid, in woodsorrel with
oxalic acid, and so on. When plants are burned these
acids are destroyed, and the base, potash, is obtained
in the form of carbonate.
The compound nature of potash was first demon-
strated in 1807 by Sir H.Davy. By exposing moistened
hydrate of potash to the action of a powerful voltaic
battery, water and potash were simultaneously de-
composed, oxygen being evolved at the positive
electrode, while hydrogen and potassium were sepa-
rated at the negative. The battery was so exceed-
ingly powerful that the metallic globules generally
took fire as soon as they came in contact with the
air, but by carefully scraping them off into naphtha
as they appeared, a supply was obtained for the
purposes of experiment.
A method of decomposing potash by chemical
means was soon after invented by Gay Lussac, and,
as improved by Brunner, is now adopted for obtain-
ing the metal in large quantities. It is as follows :-~--
The tartrate of potash, or crude tartar of commerce,
is calcined in a covered iron pot, and is thus con-
verted into carbonate of potash, mixed with minutely
divided carbon. This mass, while still hot, is to be
intimately mixed with about one-tenth part of char-
coal in small lumps, the effect of which is to make
the mass sufficiently porous to allow of the escape of
gas. The whole is quickly introduced into an iron
bottle (such as is used for importing mercury), and a
short but rather wide tube is fitted to the aperture.
The bottle is placed horizontally in a wind furnace,
so constructed that the flame of a strong fire, fed with
dry wood, may wrap round it, and keep up a uniform
heat approaching to whiteness. To the short iron
pipe is attached a copper receiver or condenser,
partly filled with rectified naphtha, and so constructed
with partitions as to exclude the air. The receiver
is kept cool by means of ice applied to the outside.
Through the receiver is passed a stout iron wire,
terminated by a screw, for clearing the iron tube of
any solid matters that condense in it. When the iron
bottle has attained the required temperature, the de-
composition of the alkali by the charcoal begins; the
oxygen of the potash and of the carbonic acid com~
bines with the carbon, forming carbonic oxide gas,
which is disengaged in abundance, while the potas-
sium distils over, and condenses in the receiver in
globules. The operation is liable to fail from the
tendency of the carbonic oxide and the potassium to
form a dark grey compound, which sublimes and
condenses in the short iron tube, from which it must
be removed by the application of the screw wire.
When the operation is most successful, at least one-
half of the metal is lost by combining with carbonic
oxide. The potassium which passes over is contami~
nated with carbon and this grey compound: it may
be obtained pure by distilling it in a cast-iron retort
POTASSIUM.
433
containing a little naphtha, the vapour of which
expels the air. The pure metal is thus obtained in
globules, which may be preserved in naphtha quite
free from oxygen. The potassium may also be puri-
fied by tying it up in a linen bag, heating it to 14100
or 150°, and squeezing out the metal under naphtha
with a pair of wooden pliers.
Potassium appears of a bluish white colour and
metallic lustre when a globule is freshly cut open.
At common temperatures it is soft and may be
moulded in the fingers like wax. At 32° it is brittle
and crystallizes in cubes; at 70° it becomes pasty,
and liquid at 150°. It boils at a dull red heat,
forming a green vapour. Its sp. gr. is 0865. So
powerful is the affinity of this metal for oxygen, that
it instantly oxidizes on exposure to the air; the
surface becomes tarnished, and a crust of caustic
potash is formed. This strong affinity for oxygen
causes it to decompose water and even ice, and the
evolved hydrogen gas and a portion of the metal
inflame and burn with a fine violet colour. When
thrown on the surface of water the ignited globnle
moves about with rapidity, and when the metal is
entirely consumed, a globule of fused dry potash
combines at a certain temperature with the water,
with a crackling explosion, and dissolves, forming a
solution of potash.
Potassium combines with oxygen in two propor-
tions, forming the protowz'dc K0 and the peroxide K03.
The protoxide of potassium, known as potassa, or
more familiarly, poms/c, is a substance of great im-
portance in chemistry, pharmacy, and the useful arts.
The only known method of obtaining it free from
water, is by exposing potassium to dry air, when it
forms a white powder, fusible at a red heat, and
volatile at a white heat. If once united with water,
it cannot be separated from it except by means of an
acid. The potash of commerce and that used in the
laboratory is always hydrated. Before carbonic acid
was known, the alkalies and their carbonates were
distinguished by the terms caustic and mild, and it is
still not unusual to name the hydrate of potash,
caustic poms/z. See ALKALI.
The hydrate of potash is prepared for use by de-
composing the carbonate by means of hydrate of lime:
10 parts of carbonate of potash are dissolved in 100
parts of water, and the solution boiled brisklyin a
clean vessel of untinned iron (silver is used for scien-
tific purposes) : 8 parts of good quicklime are in the
meantime to be slaked in a covered basin, and the
hydrate of lime thus formed added by degrees to the
boiling solution with frequent stirring: the lime
abstracts the carbonic acid from the potash, and car~
bonate of lime is formed and rapidly deposited. When
all the lime has been stirred in, the mixture is allowed
to boil for a few minutes, and is then removed from
the fire and covered up to exclude the air. In a
short time the solution will have become quite clear,
and may be syphoned off. The solution if properly
prepared, will not effervesce on the addition of
muriatie acid, showing that all the carbonic acid has
been transferred from the potash to the lime. The
VOL. II.

solution of caustic potash is rapidly evaporated in an
iron vessel as far as may be desired: if heated until
vapour of water ceases to be disengaged and then
allowed to cool, it forms the solid hydrate, KO,HO.
But instead of being allowed to cool in this form, it
is usually run into cylindrical moulds, Fig. 1666.
The mould is in two halves, which admit of being
screwed together so as to form a tight joint. The


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fused potash is poured into the trough at the top, and
when it is solidified, the sticks are taken out by un-
screwing the mould. The sticks thus produced form
the caustic potash or fuscclpot‘as/z of the shops, and
are used by surgeons as a cautery. In this stat e,
however, it is not pure; it contains sulphate and car—
bonate of potash, chloride and peroxide of potassium,
and oxide of iron; it may be purified by dissolving
it in absolute alcohol, evaporating to dryness, and
fusing the remaining potash a second time. The
pure hydrate is a white solid substance, very deli-
quescent, and dissolving in water with considerable
rise in temperature. It imparts to the fingers a
peculiar soapy feel, in consequence of its dissolving
the cuticle ; it dissolves and decomposes the organic
tissues, whence its use in surgery and its name of
caustic potash. It unites with the fat oils to form
soap, whence its aqueous solution is termed soap-lye.
[See SCAR] It is powerfully alkaline, completely
neutralizing the most powerful acids; and being the
strongest base it is employed in most cases of saline
decomposition: indeed, its uses in chemistry and the
arts are innumerable; it restores the blue colour to
reddened litmus, and turns the yellow of turmeric
paper brown; it has a nauseous and peculiar taste; it
absorbs carbonic acid rapidly from the air, and must
therefore be preserved in well—stoppled bottles of
common green glass, as it acts rapidly on glass con-
taining much alkali or lead.
The following table shows the densities and value
in real alkali of different solutions of hydrate of
potash, together with the boiling points :—
Sp. Gr. Potash per cent. Boiling point.
1 '68 ....... .. 51 2 ....... .. 329°
1'60 ....... .. 46'? ....... .. 290
1'52 ....... .. 42'9 276
1'47 ....... .. 39 6 ....... .. 265
1'44 ....... .. 36'3 ....... .. 255
1'42 ....... .. 34 4 ....... .. 246
1'39 ....... .. 32 4 ....... .. 240
1'36 ....... .. 29'4 ....... .. ‘.234
1'33 ....... .. 26 3 ....... .. 229
F F
413$
POTASSIUM.
Sp. Gr.
Potash per cent Boiling pmnt.
1'28 ....... .. 23 ‘1 ....... .. 221°
1 23 ....... .. 19'5 ....... .. 220
1 19 ....... .. 16'2 ....... .. 218
1'15 ....... .. 13 0 ....... .. 215
1'11 ....... .. 9'5 ....... .. 214
1 06 ....... .. 4 7 ....... .. 2l3
Peroxide ofpoi‘assiazn, K03, is formed when potas-
sium is burned in excess of dry oxygen gas. It is
also produced when nitre is decomposed by a strong
heat, and also to a small extent by long exposure of
hydrate of potash to the air. It is an orange-yellow
fusible substance, and is decomposed by water into
potash and oxygen gas.
Carbonate 1y“ poms/i, KO,C 02,2110. The large
demand for carbonate of potash by our various
chemical manufactories, is almost entirely supplied
by the combustion of vegetables, and hence the pro-
duction is for the most part confined to countries
where timber is superabundant, such as North
America. The sap of plants contains various soluble
salts, chiefly those of potash and of soda, in combina-
tion with certain organic acids as already noticed.
These acids are compounds of carbon, hydrogen and
oxygen, and when the plants are burnt the acids are
destroyed, while the potash and soda remain in the
ashes in the form of carbonates, these bases not
losing their carbonic acid by heat, as is the case with
the earths, lime, &c. The ashes also contain other
salts, such as chlorides of potassium and of sodium,
sulphates of potash and of soda, carbonates and phos-
phates of lime and of magnesia, and silicate of alumina.
Plants which grow near the sea mostly contain soda;
inland plants potash. The ashes of the latter are
lixiviated with water in a large cask or tun, Fig. 1667,
furnished with a false per-
forated bottom, which is
covered with straw, and
between this and the real
bottom is an aperture 0
stopped by a plug. A pipe
12 extends from the top of
the tub through the per-
forated bottom to allow the
air to escape freely from
the space between the true and the false bottom.
After some hours the liquid is drawn oif, and more
water added in order that the whole of the soluble
matter may be removed. The weakest solutions are
poured upon fresh quantities of ash instead of water.
In this process the soluble salts, such as the carbo-
nates of potash and of soda, the chlorides and the
sulphates, are dissolved. The insoluble residue con-
sists principally of silicate of alumina, and carbonate
and phosphate of lime. The solutions or Zeys are
evaporated to dryness and the residue calcined to
remove a little brown organic matter, and the pro-
duct thus obtained forms the oracle poias/zes of com-
merce. These are classified according to the locality
whence they are imported, or according to the route
by which they arrive; thus there are American,
Russian, Tar/soy, German, Moselle, Zllyrian, Saxon,
Bohemian, Danieig, and Heidelberg potashes, and these




...~._ilillit Hi mtrauma
Fig. 1667.

are seldom distinguished by their colour or appear-
ance, as is the case with pearl-ask, as the calcined
potash is termed when it has a white pearly lustre.
The weight of ashes furnished by different plants
varies in diiferent species and soils. Herbaceous
plants yield more than woody ones, and different
parts of the same plant furnish very different pro-
portions of ash; the leaves yield more than the
branches, and the bark more than the trunk. Thus
Saussure found in the pealed branches of oak 29
times as much ash as in the wood; in the bark 30
times; in the inner bark 36 times; in the sap-wood
twice, and in the leaves 36 times as much. In white
beech the sap-wood contained 1'1 times the bark,
22 times as much as the wood. Although potash
can only be produced on a large scale in countries
where timber is abundant, yet the ashes of wood fuel
are turned to useful account in all countries, either
as manure or as a soap in washing linen. In some
thinly populated countries, as in the United States of
America and the North of Europe, where wood is
very abundant, it is burned solely for the sake of the
ash. In Russia, where manure is not of much value,
straw and weeds are consumed for the same purpose.
In the north of France yeast, the lees of wine, and
the residue of the brandy distilleries, are made into
cakes, dried in the sun, and burnt for the sake of the
ash. In Java the stems and leaves of the indigo
plant, after the separation of the colouring matter,
are used for making potashes. Formerly the crude
ash was sent into the market, but this practice has
long been discontinued. The soluble portion is now
extracted by means of water, the lye is evaporated,
and the residue heated to redness as above described.
The composition of crude potash is variable, and
as its value depends chiefly on the proportion of
alkaline carbonate which it contains, it is of import-
ance to the manufacturer to be able to test the value
of the potashes as they come before him. Instructions
for the purpose will be found under ALKAmMn'rnr.1
Crude potash contains from 60 to 80 per cent. of
carbonates of potash and of soda; the remainder con-
sists of sulphate of potash, chloride of potassium, and
a small quantity of silicate of potash. It may be
purified by solution, and a carbonate of potash ob-
tained with only 2 or 3 per cent. of foreign matters.
For this purpose the crude potash is treated with its
weight of cold water, and left to digest during several
days with occasional agitation; the sulphate of potash
and chloride of potassium, being less soluble than the
other salts, remain for the most part as residue. The
liquor is syphoned off and rapidly evaporated, until
small crystals are deposited; the fire is then with-
drawn and the liquor left to cool. While the crystal-
lization is going on, the liquor is kept in agitation, in
order that small crystals only may be formed. When

(1) A good account of potash and the method of estimating its
value is given in the first volume of “ Knapp’s Chemical Techno-
logy,” translated by Drs. Ronalds and Richardson, 1848. This
volume also contains a full account of nitre. Dumas has also
some admirable chapters on the subject of potash; but the fullest
chemical account that we are acquainted with is in “ Gmelin’s
Handbook,” vol. iii.
POTASSIUM.
435
the liquor is cold it is discharged into a filtering bed,
which retains the crystals of carbonate of potash,
and these are washed with a small quantity of pure
carbonate of potash, and then dried at a stove.
A yet purer carbonate of potash may be obtained
by decomposing cream of tartar, i.e. bitartrate of
potash, by means of heat, in an iron pot. The residue
consists of a mixture of carbonate of potash and of
carbon, which is sometimes employed in the laboratory
under the name of blae/e jlare. The carbonate of
potash is dissolved out by means of water, and the
solution evaporated to dryness. Carbonate of potash
is also prepared by projecting small portions at a
time of a mixture of 1 part cream of tartar, and 2
parts nitrate of potash, into an iron pot heated to
redness. The carbon of the tartaric acid is com-
pletely burned by the oxygen of the nitric acid, and
there remains a white substance, termed wlzitejlazr,
which consists almost entirely of carbonate of potash.
It is, however, contaminated with a little nitrate of
potash.
Carbonate of potash is very deliquescent, and is
soluble in less than its own weight of water; the
solution is very alkaline. This salt is insoluble in
alcohol. When exposed to heat the water of crystal-
lization is driven off, and at full ignition the salt
fuses, but is not otherwise changed.
Bicarbonate of potash, KO,COg+I-IO,CO‘2. This
substance is obtained by passing a stream of carbonic
acid through a cold solution of potash; the gas is
rapidly absorbed, and a white crystalline substance
separated. It is collected, pressed, redissolved in
warm water, and left to crystallize. It forms large
and beautiful crystals, the form of which is derived
from a right rhombic prism. On the continent the
supply of carbonic acid for this manufacture is econo-
mically obtained from the fermentation of sweet
wines and liqueurs, and in some localities the carbonic
acid disengaged from the earth is employed for the
purpose.
Bicarbonate of potash is much less soluble than
the simple carbonate, a parts of cold water being re-
quired for solution; the solution has a milder taste
than that of the former salt, and is nearly neutral to
test paper. Carbonic acid is disengaged by boiling
the solution; the crystals are also decomposed by
heat, water and carbonic acid being evolved; and the
simple carbonate remains.
Nitrate QfpOMS/l, KO,NO5. This salt, also named
nitre or saltpetre, is a natural product, but may be
prepared by the addition of nitric acid to potash, or
to carbonate of potash. The liquor, on being evapo-
rated, deposits anhydrous crystals, which are six—
sided prisms with dihedral summits. This salt is
soluble in 7 parts of water at 60°, and in its own
weight of boiling water. It has a cooling and saline
taste, but has no action on vegetable colours. It
fuses at a temperature below redness, and is com-
pletely decomposed under a strong heat. When
mixed with combustible matter and heated, or thrown
in a fused state on many metals, rapid oxidation takes
place at the expense of the oxygen of the nitric acid.

Gunpowder is an example of such a mixture, and
there are many such in various pyrotechnic composi—
tions, which burn independently of the atmospheric
air, and even under water, oxygen being abundantly
supplied by the nitric acid. See GUNrowDER.
In India, Egypt, and some other warm countries,
after the rainy season, nitre is produced on the
surface of the soil in the form of a white efilorescence.
The soil is removed to the depth of about an inch,
and treated with water, which dissolves the soluble
salts. The solution is made in large basins or tanks;
rapid evaporation takes place under the influence of
the solar heat, and is completed by means of artificial
heat: as the solution cools, a considerable quantity
of nitrate of potash is deposited in large crystals.
This forms rang/i Indian nitre. The mother liquor is
thrown away; it contains a considerable quantity of
nitrate of lime and magnesia, and might still furnish
nitre if mixed with potash salts. Bengal and the
neighbourhood of Patna are the sources of the largest
portion of the saltpetre supplied to the European
market from Hoogly. In Hungary there are salt—
petre pits, and in some parts of Spain the soil becomes
incrusted with this substance.
Nitre is also obtained from certain natural caverns
occurring in the limestone rocks of the island of
Ceylon: the walls become covered with a nitrous
efllorescence, which is detached, during six months of
the year, with picks, together with a small portion of
the rock which contains felspar, and this is doubtless
the origin of the potash. The fragments are pounded,
mixed with an equal portion of wood-ashes, and water
is poured upon the mixture. The nitrates of the
earths part with their acid to the potash in the ashes,
and the earths are precipitated as carbonates of lime
and magnesia. The clear decanted lye, containing the
nitre of the ashes as well as that of the rock, is evapo-
rated inpits exposed to the sun, and then in pans
by the action of fire. The crude saltpetre, which
crystallizes in cooling, is then fit for exportation.
Similar caves exist in Italy, on the coast of the
Adriatic, in North America, Africa, Teneriffe, &c.
In France, nitre was formerly produced artificially
in what are termed nitre-heels, by the oxidation of am-
monia in the presence of a powerful base. Animal
refuse of all kinds was mixed with old mortar, or
hydrate of lime and earth, and the mixture was placed
in heaps under a cover of some kind, to keep ofi the
rain, but with free exposure to air. The heaps were
watered from time to time with stale urine, and the
mass was turned over in order to expose fresh sur-
faces to the air. When a considerable quantity of the
salt had been formed, the mixture was lixiviated,
in troughs of oak-wood, Fig. 1668. In one of the
longer sides of each trough, between the stays ss,
were holes li ii, for the reception of tubes or cocks to
conduct the fluid into the gutter g ; and in order to
keep back the earth, &c., an inclined board pierced
with holes was placed inside, as shown at b, Fig.1669,
and this was covered with straw or willow twigs.
The iron rods r prevented the sides from bulging. The
solution was pumped up several times from the
FF?
A36
POTASSIUM.
gutters, and when it had passed repeatedly through
the trough, it formed the crude lye. This contained


Fig. 1668.
nitrate of lime, mixed with carbonate of potash: car-
bonate of lime was formed while the nitric acid passed




"s
Fig. 1669.
over to the potash. This solution was then evapo-
rated to the crystallizing point by boiling in large
coppers similar to that shown in Fig. 1670. The
scum was removed by proper tools into a vessel above
the level of the copper, so that the water might drain
back into the copper. Earthy matters in the salt
would tend to form a deposit, but the currents produced
by the ebullition caused them to circulate, and as the
heat was greatest near the sides, the currents would
there be ascending ones of considerable force; the
descending currents, on the contrary, would be formed
among the central and cooler portions of the liquid;
so that the earthy matters raised by the ascending
currents at the side would be carried along to the
s /‘z
'@
1 Y-
‘i
slur .
ikfiu t j 1


\\\‘ \\\\\ ‘ ‘
‘it as“ s
' 1 ~ 1
will I |
pl"
\\ s\\\\
A \ \\\ .\\\\
.\ \\ \
m
.\
\\\ \
I ll!

\\\\ \\\\\\‘l\\\\\\\ _, V S
\\\\\\\\\\\\\\\\ss\\\\\\\\\\\\\\\\\\s\\\\\\\\s\\\\xssm
Fag. 1670.
centre and descend with the liquid. Now by an in-
genious contrivance a small vessel 72, Fig. 1670, was
suspended by a chain and pulley p in the centre of
the vessel, and the earthy matters, instead of falling
to the bottom of the boiler in the downward course,
were received and retained by this small vessel, while
the water of the downward current passed over its
sides to the bottom. Every now and then the vessel
n was raised, and its contents turned out, and in this

way a large proportion of the earthy matter was
separated. The solution thus concentrated by boiling
was next crystallized, and the crystals were purified
by being dissolved and crystallized several times.1
Now that nitre is freely imported into France from
foreign parts, this plan, which is tedious and costly, is
no longer adopted; but it was, in its origin, of great
importance to France, when that country, towards the
end of the last century, was surrounded by enemies,
and all communications with foreign countries cut off.
By this method alone was she able to procure supplies
of saltpetre for the manufacture of gunpowder, and
one of her most illustrious chemists, Berthollet,
traversed France from one extremity to the other,
giving instructions for carrying out the plan. At the
present time there are, however, in Prussia, Sweden,
and other parts of Europe, what are called saltpetre
plantations, walls, and heaps, in which this salt is arti-
ficially produced.
In populous towns, where the excrements of ani-
mals, refuse from slaughter-houses and various trades,
the water from the houses, the refuse of markets,
&c., mix with the fluid matter of the drains and
are in a constant state of putrefaction, the coat-
ing of mortar on external walls, especially at the
base, becomes covered with a white, floccular, crys-
talline efliorescence: this causes much injury to
buildings, and is known as salfpet‘rez'ng or saltpetre
rot. The same phenomenon also occurs in other parts
of the walls not so exposed. See PLASTEBING.
The rough nitre as imported into Great Britain
from the East Indies, is in broken crystals of a brown
colour, and more or less deliquescent. The loss which
it sustains in refining is termed the reflection, and can
only be ascertained by analysis; but it is not easy
to obtain a fair sample of a cargo. “The samples
which the merchants and brokers select for analysis,
generally consist of portions drawn from each bag and
afterwards mixed together, and if carelessly or un-
fairly taken, or exposed so as to become more moist
or more dry than the bulk, the report of the analyst
is often unsatisfactory. He should work upon not
less than 20 to 30 lbs. of such sample, which should
be ground or triturated so as to produce a properly
uniform mixture of the whole, for it often includes
lumps of pure nitre or of other salts: from 100 to
1000 grains of this mixture is then taken for analysis.
The moisture is determined by the loss occasioned by
careful drying on the sand-bath : it is then dissolved
in water and tested, so as to acquire some general
notion of the impurities ; and by means of nitrate of
silver, nitrate of baryta and oxalate of ammonia, the
proportion of chlorine, sulphuric acid, and lime may
be determined: the lime is generally in the state of
sulphate, and more or less sulphate of potassa is also
usually present. The chlorine is chiefly derived from
the chlorides of potassium and sodium. Another
portion of the sample should be dissolved in about
thrice its weight of boiling water and filtered, by
which any sand or other insoluble impurities are

(l) The process is fully described in Thenard’s Trazte' de Chimie,
and also in Dumas, Chimz'e Appliq'uée a'aa: Arts, tom.
POTASSIUM.
437
collected: the salt should then be crystallized in the
usual way, during which the appearances and forms of
the successive deposits will indicate, to the experienced
eye, the nature of the foreign salts present, among
which nitrate of soda, sulphate of potassa, sulphate
and nitrate of lime, and chloride of sodium and potas-
sium, with traces of chloride of calcium, and some-
times of a peculiar organic matter, are frequently
found. It will be obvious that the accurate quanti-
tative analysis of such a mixture of salts is not avery
easy problem; and yet the separation of nitrate of
soda from nitrate of potassa, and of chloride of potas-
sium from chloride of sodium, are essential steps, as
the value of the sample is affected by their relative
proportions : for nitrate of soda, to say nothing of its
unfitness for the manufacture of gunpowder, is cheaper
than nitrate of potassa; and chloride of sodium is of
no value, whereas chloride of potassium is purchased
by the alum-makers ; so that a sample of nitre, con-
taining the latter salt, is in this respect worth more
than where it only contains common salt. But inas-
much as the equivalent of chloride of sodium is only
60, and that of chloride of potassium 76, it is obvious
that if the whole of the chlorine, as indicated by the
weight of the chloride of silver, be considered as in
combination with sodium (part of the sample consist-
ing of chloride of potassium), the refraction will be
estimated below the mark. Hence the necessity of
ascertaining the relative proportions of both chlorides,
which is best effected by converting them into sul—
phates and separating them by crystallization.n1
The refining of nitre on a large scale is founded on
the property that its solubility increases rapidly with
the temperature, while the solubility of the chlorides
of sodium and of potassium remains nearly constant.
For example, about 25 cwt. of rough nitre is dissolved
in the large copper boiler B, Fig. 1670, in 150 gallons
of water; the heat is gradually raised, and fresh por-
tions of nitre are added until about 60 cwt. have
been dissolved. The solution is kept stirred, and the
scum removed. The water in the boiler, when raised
to the proper temperature, is sufficient to dissolve the
whole of the saltpetre, but not the whole of the foreign
salts: a large portion of the chloride of sodium sub-
sides, and may be scooped out of the boiler. 100
gallons of water are then gradually added so as not
to cool the solution too much; 2% lb. of glue dissolved
in warm water are then poured in, and the whole
thoroughly agitated. The glue thus diffused through
the liquid becomes entangled with the organic sub-
stances which rendered the solution viscous, and rises
with them to the surface in the form of scum, which
is carefully removed, and after boiling for some time,
the liquor becomes clear. The fire is then withdrawn
and the temperature let down to about 195°, when the
liquor is carefully dipped out and removed to the crys-
tallizing vessels. The liquor must be disturbed as little
as possible during this operation, in order not to sus-
pend the crystals of common salt deposited at the
bottom. The crystallizing vessel is a shallow copper

(1) Brande. “Manual of Chemistry.”
- solves the chlorides.

vessel, the edge of which is firmly screwed to a plat-
form of oak t, Fig. 1671. It is formed with two in-
clined planes, .,
and purposely
made deeper at
one part 41, Fig.
167 2, than in
any other. As







4
, 7/


.1.
V v


Fig. 1671.
the liquor cools, the crystals quickly form, and if
left tranquil they are of large size and clustered


Fig.1672.‘1
together, the consequence of which is, that portions
of the mother liquor become confined within the
groups, and the nitre becomes contaminated with
those very salts which it is the object of this
refining process to remove. But if the liquid be
constantly agitated during the crystallization, the
salt forms into small prismatic crystals, from which the
mother liquor can afterwards be readily removed by
washing. As fast as the crystals are formed they are
raked up towards the top of one of the inclined planes
of the trough, and thus the mother liquor drains back
into the liquid. As soon as the salt is dry it is
removed to make way for the remainder of the crop
of crystals, which are gathered until the liquor sinks
down to near the temperature of the air. The crystals
of saltpetre are next washed in tubs, one of which
is shown in plan and section, Figs. 1673, 1674,
containing a
false bottom


drilled with \p 1",”.
holes;thetub \ ~ 5:"
is filled with . . _ ‘v ‘.5155;
the salt and ‘I heaped up ‘ “51%”
Fig. 1673.
some inches
above its rim. A cold saturated solution of pure
nitrate of potash is poured over the salt so as tho-
roughly to wet the
mass. Of course this
solution is not capable
of dissolving saltpetre,
since it is already
saturated with that
salt, but it readily dis-
The whole is left in this con-
dition for some hours, after which the opening at 2,‘
is unstopped, and the water flows off into the gutter g.
When the salt is thoroughly drained, it is sprinkled
with pure water, which is left upon the salt for a
couple of hours; it is then drained off, saturated
with nitrate of potash and containing some traces of
chlorides. The saltpetre thus refined is dried in the
shallow vessel v, Fig. 1670, which is heated by the
flue, f fi of the furnace fire, which winds under it in
its way to the chimney c, the draught being regulated
by a damper cl. The salt is continually stirred during
the to prevent it from forming into masses.





Fig. 1674.
438
POTASSIUM.
Snhahate 0/” potash, KO,SO3. In the manufacture
of nitric acid from nitrate of potash [see Nrrnrc
Acin], the acid residue left in the retort is dissolved
in water and neutralized with crude carbonate of
potash; the solution, on cooling, yields hard trans-
parent crystals of the neutral sulphate, which may be
purified by re~dissolving in boiling water, and re-
crystallizing. This salt is soluble in about 10 parts
of cold, and in a much smaller quantity of boiling
water: it has a bitter taste, and is neutral to test
paper. The crystals are anhydrous and decrepitate
when suddenly heated. They are insoluble. in, alcohol.
There is a bisulphate of potash consisting of KO,S()3
+H0,303, and an anhydrous bisulphate consisting
of K0,2S03.
Chlorate of potash, KO,GlO5. When chlorine is
passed into a warm and moderately strong solution
of caustic potash, or of carbonate of potash, and the
liquid concentrated by evaporation, flat tabular crys-
tals of chlorate of potash are obtained. In this pro-
cess a portion of the potash is decomposed, its oxygen
combines with one portion of chlorine to form chloric
acid, while the potassium is taken up by a second
portion of chlorine, and chloride of potassium remains
in the mother liquor. The reaction may be thus re-
presented :—
6 equiv. 5 eq. chlorine 5 eq. chloride
chlorine 1 eq. chlorine of potassium.
_ 5 eq.potassium
6 equiv’ { 5 eq. oxygen
poms 1 eq- Potash 1 eq. chlorate
of potash.
The crystals of chlorate of potash are anhydrous,
flat, and tabular: they are soluble in about 20 parts
of cold and 2 of boiling water: their taste somewhat
resembles that of nitre. This salt affords a ready
means for obtaining oxygen gas. [See OXYGEN] It
deflagrates violently with combustible substances, and
friction or percussion often produces explosion. A
few grains of this salt and of sulphur rubbed up
together in a mortar produce a series of loud crack-
ling explosions. Attempts have been made to sub-
stitute this salt for nitre in the manufacture of gun-
powder, but a number of fatal explosions rendered
the application impossible. A large quantity of it
is consumed in the manufacture of lucifer matches
and fusees in conjunction with phosphorus. [See
Marenns—Pnosrnonus] All those matches which
burst into a whitish flame with a slight explosion and
a kind of roaring noise contain this salt. Those
matches which ignite quietly on gentle friction, con-
tain no chlorate of potash, but a good deal of common
phosphorus.I

(1) We take this opportunity of stating that since the date of
Messrs. Dixon’s letter, as quoted under Prrosmrorms, p. 392, note,
those gentlemen have resumed their attempts to employ amorphous
instead of common phosphorus in the composition of the paste
used for tipping the matches. These attempts have been attended
with such success as to lead to the hope that in the course of a
few months the public will be supplied with amorphous phos-
phorus matches. A box of these matches has lately been forwarded
to the Editor, and he is happy to be able to report favourably of
them. They ignite with moderate friction; they have no smell,
and they produce no light in the dark under 400° ; they are not

Ioelicle ryopotassinm, KI, may be prepared by adding
iodine to a strong solution of caustic potash: the
iodine is largely dissolved, and a colourless solution
formed of iodide of potassium and iodate of potash.
The reaction is similar to that with chlorine and potash.
When the solution begins to retain the colour of the
iodine, it is evaporated to dryness, and cautiously
raised to a red heat, which converts the iodate of
potash into iodide of potassium. The mass is then
dissolved in water, filtered, and crystallized. The
crystals are in cubes often milk-white and opaque:
they are anhydrous, but fuse readily when heated.
They are soluble in water and in alcohol, and if pure,
not deliquescent in tolerably dry air.
Bromicle of potassium, KBr, may be formed in a
similar manner, using bromine instead of iodine. It
is a colourless, soluble salt, resembling the iodide.
Saqiharets of potassium. There are three distinct
compounds of potassium and sulphur, viz. KS,KS3,
and KS5. The simple, or monosnlphnret of potassium,
may be formed by the reduction of sulphate of potash
at a red heat, by means of hydrogen or charcoal—
powder. There are also other methods. It is a crys-
talline mass, of a cinnabar-red colour, very soluble in
water: the solution has an offensive and caustic
taste; it is readily decomposed by acids ; sulphuretted
hydrogen being evolved, and a salt of the acid used to
decompose it, formed. This sulphuret is a strong
sulphur base, and forms crystallizable saline com-
pounds with the sulphurets of hydrogen, carbon,
arsenic, &c. The higher sulphurets are obtained by
fusing the simple sulphuret with different proportions
of sulphur.
Our limits will not allow of a fuller notice of the
various salts of potash; but we may conclude with a
brief statement of their general properties. The salts
of potash may in general be recognised—1. By their
physical characters, but chiefly by those of the sul-
phate, an anhydrous and readily crystallizable and
tolerably hard salt. 2. By the property of forming
alam, a double salt, with sulphate of alumina, which
crystallizes readily in regular octahedrons. All that is
necessary is to pour into a saturated solution of a
potash salt, a saturated solution of sulphate of alu-
mina, and to agitate the mixture, when a crystalline
precipitate of alum will be formed. 3. By the property
of forming, with tartaric acid, a bitartrate of potash,
but little soluble in water; so that if we form a
solution of tartaric acid into a moderately strong
solution of a salt of potash, a white crystalline pre—
cipitate of cream of tartar is formed. 4.‘. By the pro-
perty of giving with chloride of platinum, under
similar circumstances, a crystalline yellow precipitate,
which is a double salt- of chloride of platinum and
chloride of potassium. 5. By forming slightly soluble
precipitates when perchloric acid and hydrofluosilicic

liable to contract damp, and may be placed on a hot mantel-shelf
without taking fire. It is earnestly to be hoped that the use of
common phosphorus may soon be superseded by the amorphous
kind, in order to exterminate a cruel disease among the opera-
tives, and to introduce a safer and. better article into general
domestic use.
POTATO—POTTERY AND PORCELAIN.
1139
acid are added to a potash salt. 6. By colouring
purple or violet the outer flame of the blow-pipe.
POTATO. The potato (Solanarn taterosznn) con-
sists of water, starch, gum, albumen, and lignin.
According to the analysis of several kinds, the water
varies from 73 to 81'?) per cent; the starch, from 9'1
to 152; the gum, from 1'7 to Al; the albumen,
from 0"7 to 1'9; and the lignin, from 52 to 8'8.
The quantity of solid matter varies with the state of
ripeness of the tuber; the ripest lose from 68 to 70
per cent. in drying. Those potatoes keep best in
which the starch is most abundant; but the starch
diminishes by keeping, and probably passes into gum
and sugar. The proportion of albumen also diminishes.
The cause of the potato rlisease, as it is termed, has
not been explained by the researches either of the
chemist or the botanist.
POTTERY AND PORCELAIN. The term pot-
tery, derived from potam, a drinking vessel, is applied
to all ware of the opaque kind; while porcelain, a
word of doubtful origin, applies to that which is trans
lucent.
Snc'rion I.-—HISTORICAL NOTICE.
The art of making potterg, or vessels of baked earth,
is so ancient and so universal that we seek in vain
for any precise information as to its origin. It is
alluded to in that most ancient record, the book of
Job, and is also repeatedly mentioned in other parts
of the Scriptures. The potters of Samos were cele-
brated in the time of Homer; and great quantities of
pottery have been found in Egyptian tombs, which,
to all appearance, have lain unopened since the time
of the Pharaohs. The earliest use of pottery was
doubtless that of ordinary drinking vessels ; but there
was also a religious employment assigned to'earthen
vessels, which has been the means of preserving them
for the inspection of after generations. In vases of
baked earth the ashes of the dead were frequently
deposited, and even where the practice of burning
the dead was not followed, still various earthen
vessels have been found placed at the head and feet of
the skeleton, and sometimes hanging on pegs along
the sides of the tomb. Thus among many distant
nations, having different languages, manners, and
superstitions, pottery was considered a necessary part
of the furniture of tombs.
The potter’s art is extremely valuable in an anti-
quarian point of view. While metal is liable to
corrosion, and wood to decay, pottery remains almost
unalterable, and has thus been the means of discover-
ing to later ages many points respecting the history,
religion, customs, and manners of the ancients, which
must otherwise have remained unknown. The potter’ s
art is represented in all its stages on the tombs of
Thebes. The mixing of the clay was effected by
kneading with the feet; after which a. mass of con-
venient size was formed with the hand, and placed on
a wheel of very simple construction, and turned with
the hand. During its revolution the forms of the
vessel were made out with the finger; the handles
were afterwards affixed; the objects were placed on

planks to dry, then carefully arranged in trays, and
carried to the oven. Ornamental designs were traced
with a wooden or metal instrument previous to the
baking.
There is a general agreement in the nature and
uses of ancient pottery, but at the same time a dis-
tinctive character belonging to each country and
nation. In this distinctive character consists the
value of pottery in an historical point of- view. The
rude and simple urns of the early inhabitants of these
islands; the more carefully fashioned pottery of the
Romans with which our country abounds; the simple
unglazed earthenware of ancient Greece; the more
elaborate forms called Etruscan, of which the finest
specimens are, however, attributed to the Greek
potters of the Isle of Samos, so celebrated for the
delicacy and perfection of their workmanship; the
red and black potteries of India; the black and white
potteries of North America, the latter interspersed with
fragments of bivalve shells; the irregularly formed
and fanciful pottery of South America ;——all these
possess a distinct individuality which makes them
clearly recognisable by the student of this interesting
art, while it reveals many valuable facts, taken in con-
nexion with the localities in which they are found,
their greater or less simplicity, their modes of
ornamentation, and the relics which they frequently
enclose. On the discovery of the extraordinaijr ruins
of Mitla and Palenque, in Mexico, not many years
ago, numerous specimens of pottery were met with,
of a remarkably advanced kind for the period assigned
to those ruins, namely, one thousand years before the
Christian era. These potteries, although made with-
out the turning lathe, are ornamented in different
colours, well baked, and covered with a fine vitreous
glaze, such as was unknown to Europeans until about
ten centuries ago.
As other branches of art advanced, so the potter’s
art became more and more developed, until at last a
very fine hard description of pottery, thin and trans-
lucent, was invented and manufactured under the
name of porcelain, a word», according to some, derived
from porcellana, the Portuguese for a drinking-cup;
according to others, from the Italian word porcellana,
a univalve shell, of the genus cgprceicla or eozories,
having a high arched back like that of the hog (porno,
Ital.), and remarkable for a white, smooth, vitreous
glossiness of surface. This is the more probable deri-
vation, since there is abundant evidence that the
word porcelain existed in the French language in the
fourteenth century, and consequently anterior to the
introduction of Chinese porcelain into Europe.
Porcelain is of comparatively recent origin in
Europe, yet it was commonly known in China more
than a century before the Christian era. It was not
until four or five centuries after that period, how-
ever, that fine materials were employed, and that
some degree of perfection was attained. Still, taking
the later date, the porcelain of China has a high anti‘
quity, and must have been made at least 1250 years
before our English porcelain. IVhen the Chinese had
acquired a certain amount of skill and perfection,
440
POTTERY AND PORCELAIN.
they appear to have rested entirely satisfied with the
results, and to have continued producing them with-
out variation for ages. So exclusively were the
Chinese the manufacturers of porcelain, that it ac-
quired the name of their land, and became universally
known (on its introduction to Europe in 1518) as
Clz'na. For a long period it was also erroneously
supposed that the fine clay necessary for the produc-
tion of good porcelain, consisting of silica and alu-
mina in variable proportions, and called by the Chinese
lanolin, was peculiar to their land, and that conse-
quently no country in Europe could hope to attain
eminence in this manufacture.
Yet the beauty of china led to many attempts at
its imitation; success, however, was slow to attend
them, for it was not until nearly 200 years from the
above date that pure white porcelain began to be
manufactured in Europe. Saxony was the birth-place
of this manufacture, and Frederic Bottger, or Bottcher,
the successful potter. This individual, originally
an apothecary’s apprentice, and long engaged in
the vain endeavour to transmute the baser metals
into gold, had also laboured hard to discover the
method of making china, but could only produce a
sort of red ware, which was much admired at the
time, but was greatly inferior to porcelain. While
engaged in the search for a better material for his
ware, it happened that a merchant named Schnorr,
being on a journey, was struck with the appearance
of a white-looking earth near Schneeburg, and col-
lected some of it, thinking it might be used instead
of wheaten flour in the manufacture of hair-powder.
In this idea he was not mistaken, the only drawback
being that the wigs dressed with the new hair-powder
were very heavy. B6ttger noticed the increased
weight of his wig, and no sooner discovered that the
new powder was earthy in its character than he saw
in it at once the long-sought material for porcelain:
and on trial it proved that he could make with this
substance (long afterwards known as Schnorr’s white
earth) a porcelain as white as that of China.
The manufacture of Dresden china thus com-
menced, about 1709-1710, under the direction of
Bottger, was carried on with the greatest secresy,
and the exportation of the earth was forbidden
under heavy penalties. The manufactory itself is at
Meissen, near Dresden, and although at this day
strangers are permitted to visit it, (the Editor has
shared in the privilege,) yet at the time of which we
now speak it was treated precisely as a stronghold,
the drawbridge was only lowered by night, and the
work~people were sworn to observe “ Secresy to the
Grave,” this being the motto affixed to the doors of
the workshops, and kept constantly before their eyes.
So completely successful was Bfittger in his attempts
to imitate the porcelain of China, that the most ex-
perienced eye can scarcely detect the difference in
colour, form, painting, or gilding between his works,
still exhibited in Dresden, and those of the Chinese.
For about thirty years the secret was kept, but gra-
dually the work-people were won from their allegiance,
and sold their skill and knowledge to other masters. l

Thus the manufacture spread to Vienna, Miniich,
&c., and porcelain works were established in several
states of Germany. Great efforts were made in
France to promote a similar manufacture, and a fac-
titious paste was introduced consisting (it is said) of
nitre, sea salt, alum, soda, gypsum, and sand, reduced
to a frit and mixed with one-third its own weight of
chalk, and calcareous marl. Of this a porcelain was
manufactured, since known by the title of tender
porcelain, to distinguish it from the hard porcelain of
Dresden and of China. This was fabricated at much
cost and trouble, and was brilliant and highly suscep-
tible of ornament. In turning this description of
porcelain a saline and siliceous dust was produced,
very injurious to the workmen, and productive of
asthma and consumption. The term lencler does not
imply softness, but is meant to express two qualities
of this ware, viz. that the paste is fusible at a lower
temperature than that at which the hard porcelain is
baked; and the glaze is capable of being scratched
with a steel point. This tender porcelain was alto-
gether different from the soft porcelain of the present
day.
The endeavours to imitate the porcelain of Dresden
and China were continued in France, and were
greatly furthered by the discovery, in 1768, of an
abundant supply of fine porcelain earth in a ravine at
St. Yrieix, near Limoges. The wife of a surgeon
had collected some of it for the purpose of bleaching
linen, when her husband, suspecting its real value,
took it to Bordeaux, and on trial it was found to
be the very thing needed as a base to the real hard
porcelain. The manufactory of Sevres, already cele-
brated, acquired from this time an increased renown
for the hardness as well as extreme beauty of its
porcelain. M. Alexandre Brongniart became director
of this manufactory in 1800, and to him we are in-
debted for the best and most interesting of works on
the ceramic art.1 The art of making glazes for the
finer descriptions of pottery had been greatly advanced
in France during the sixteenth century by Bernard
dc Palissy, a remarkable man, who acquired fame and
fortune by his discoveries, and yet cheerfully closed
his life in prison, rather than deny Protestant truth,
or bend the knee before the images which he had
made. In the early English porcelain, a fine sand
brought from Alum Bay, in the Isle of Wight, was
mixed with plastic clay and powdered flint glass, and
covered with a leaden glaze. This manufacture was
carried on at Chelsea, and had considerable success.
In 1748 it was transferred to Derby. The Worcester
Porcelain Company (which still exists) was esta-
blished in 1751, and to its originator, Dr. Wall, is
ascribed the invention of printing on porcelain by
transferring printed patterns on paper to the biscuit.
A few years later the manufacture of porcelain com-
menced in Staffordshire. In 1800 Mr. Spode manu-
factured a porcelain in imitation of the ancient
tender porcelain of Sevres, and introduced calcined

(1) “ Traité des Arts Céramiques ou des Poteries, considérées
dans leur Histoire, leur Pratique, et leur Théorie.” In 2 vols. 8V0.
with an Atlas of plates; Paris, 1844.
POTTERYv AND PORCELAIN.
441
bones in the paste. His establishment, now in other
bands, still constitutes one of our most extensive
porcelain works. Notwithstanding all these efforts,
however, the porcelain manufacture in England
was less successful than that of the finer kinds of
earthenware. These were fabricated in great beauty
and perfection by Josiah Wedgwood, whose ware was
much esteemed for its excellent workmanship and its
cheapness. The same qualities still bring celebrity
to the manufactures carried on in Staffordshire, where
an extensive district embracing many towns and
villages is known throughout the kingdom under the
title of the Potteries. One of these villages was
built by Wedgwood, and called Etruria. The first
important step in the improvement of the ordinary
potter’s work carried on in this district, was made
about 1790, when two brothers named Elers arrived
from Holland, and brought certain secrets of the
trade, which for a time were closely kept, until one
Astbury, feigning to be of weak mind, obtained access
to their works, and discovered their processes. To
this man is ascribed the introduction of calcined fiints
in the composition of cheap stone-ware. This was
an important discovery, and paved the way for the
perfection afterwards attained by Wedgwood. The
principal inventions of Wedgwood were a beautiful
kind of table ware, called, by royal command, Queea’s
ware; a terra cotta, which could be made to resemble
porphyry, granite, &c.; basalts, or black ware, which
would strike sparks like a flint; w/a'te porcelain
bz'scza't, with properties similar to the basalt; 6amtoo,
or cane-coloured biscuit; jasper, a white biscuit of
exquisite delicacy and beauty, fit for cameos, por-
traits, &c.; and a porcelain biscaz't little inferior to agate
in hardness, and used for mortars in the laboratories
of chemists.
The value of Wedgwood’s discoveries is fully
appreciated by eminent French manufacturers. A
French authority confesses that the English surpass
all other nations in the fabrication of a stone-ware
remarkable for lightness, strength, and elegance, and
also in printing blue figures upon it of every tint by
processes of singular facility and promptitude. Another
French authority truly states that the excellent work-
manship of the English ware, its fine glaze, impene-
trable to acids, its beauty, cheapness and convenience,
have given rise to a commerce so active and so uni-
versal, that in travelling from Paris to St. Peters-
burg, from Amsterdam to the furthest part of
Sweden, or from Dunkirk to the extremity of the
South of France, one is served at every inn upon
English ware. Spain, Portugal, and Italy are sup-
plied with it, and vessels are laden with it for both
the Indies, and the continent of America.
The annual production of the English potteries is
now estimated at no less than 2,000,000L; I85
factories being engaged in this branch of labour: 52
are scattered over the country at Leeds, Stockton,
Sunderland, Glasgow, Bristol, Swansea, &c., and 133
are in North Staffordshire, where 60,000 persons are
employed in the “ Potteries.” Last year 84,000,000
pieces were sent out, representing a value of

1,122,000l. This exportation (except in a small
number of countries where English pottery is prohi-
bited or submitted to heavy duties) is scattered over-
the entire world. A very limited number of countries
can supply themselves with earthenware or china;~
those precisely in which the arts and sciences are most
advanced. The immense continent of America has
not produced to this day anything of the kind worth‘
mentioning; and if we put aside the Chinese, we
shall not find more than three nations who can export
pottery to any extent. England first, then France,
then Germany; but the last to a much smaller
extent.
In 17 68 certain mineral substances were found in
Cornwall, possessing similar properties to the per-
celain earths of China, [see CLAYJ and this led to
the manufacture of a superior quality of porcelain.
Very beautiful productions are now obtained in the
various British porcelain works, yet these, with few
exceptions, do not admit of being classed with true-
hard porcelain. They are baked at a much lower
temperature than the German or Oriental porcelain,
are produced on an extensive scale, and at moderate
cost. To quote a recent writer on this subject,
“The English porcelain may be considered as holding
a place intermediate between the hard porcelain of
China and Germany, and fine stone-ware. It is dis-
tinguished from the first by the paste being more
friable, and by its plumbiferous glaze; and from the
second by its transparency and its stronger glaze.”
These remarks, however, do not apply to the excellent
hard porcelain for chemical purposes manufactured by]
the Messrs. Minton, for the first time in 1850.
In concluding this outline of the history of
pottery and porcelain, we must refer to the collec-
tions which have been formed from time to time by
private individuals in this country; and also to the
valuable national collections at Dresden, Sevres, &c.,
to which the student should repair (if opportunity
offers) for instruction. One of the richest and most
remarkable of private collections is that of the Duke
of Hamilton, which includes a portion of the rare and
curious pieces once exhibited at Fonthill Abbey,-
with a miscellaneous collection of extraordinary
interest. The Earl of Harewood possesses a most
important collection of Sevres china, the greater part
of which was formed by his uncle (known as Beau
Lascelles) ; so also does the Earl of Lonsdale. Sevres
china has also been largely collected by the Hon.
John Ashley, R. Bernal, Esq, C. Baring Wall, Esq.,
and numerous other admirers of 'the ceramic art. A
list of collectors before us reaches to nearly one
hundred,1 and we have good authority for saying that
this number might be doubled, so extensive is the
taste for making collections of pottery and porcelain.
It is interesting to observe, that individual collectors
have had their peculiar tastes for different kinds of
ware; and thus no doubt the history of the art has
been served, by a more extended research after the

(l) “ Collections towards a History of Pottery and Porcelain in
the 15th, 15th, 171211, and 18th Centuries,” by Joseph Marryat. 8V0.
London, 1850.
1M2
POTTERY AND PORCELAIN.
manufactures of particular persons or periods. While
the china of Sevres and Dresden is in favour with the
majority of collectors, there are also collections in
which the less known wares figure prominently.
Thus the Duke of Norfolk, the Hon. Sidney Herbert,
Lord Hastings, and others, have collected the ware
known as Majolica; I. K. Brunel, Esq. has turned
his attention to Palissy ware; Lady Stafi'ord has
collected ancient pottery; the Earls of Warwick and
Harrington, and Sir A. de Rothschild are among those
who have studied fa'ience; the Duke of Marlborough’s
collection is chiefly oriental; Lee Jortin, Esq. has a
collection of the ware named after Luca della Robbia;
and so on. The English manufacture of former days
is also recorded in such collections of Chelsea ware
as those made by the Earls of Gadogan and Ennis-
killen; of Worcester ware by the Earl of Glengall;
of Wedgwood ware by T. de la Rue, Esq.
The earliest in celebrity among national collections
of porcelain is that of the Japanese Palace at Dresden.
This was founded by the Elector Frederick Augustus
I., who purchased the building and enriched it with
a quantity of oriental porcelain obtained from Holland,
and whose love of porcelain carried him so far, that
he exchanged his finest regiment of dragoons with
Frederick William of Prussia, for about two dozen
large vases. His son, possessing a similar taste for
the ceramic art, arranged and added to the magni-
ficent collection. It is now one of the well—known
objects of interest in the Saxon capital, and although
the Editor, for his own part, must confess to the fact
of finding the assemblage more curious than beauti-
ful, yet it is undoubtedly one of great importance in
a national point of view. The oriental china alone
occupies thirteen rooms, beginning with the unglazed
red ware of Japan, ornamented in red, white, and
black, and richly gilded, and proceeding to some rare
and valuable vases in all shades of blue, as well as
bull‘ and brown, arranged in what is called “ the Blue
Gallery.” Then there are no less than eighty-two
large vases, with green, black, red, and blue orna-
ments on a white ground. There are also strange
and eccentric subjects and monstrous figures in
porcelain, painted and enamelled ware, snake-por-
celain, and white ware in immense variety, the last
named being fabricated in such unexpected forms as
figures of deities, lions, cows, elephants, &c. There
are also specimens of the Dresden manufacture from
its infancy to its ultimate perfection, and these would
have been much more complete had not political
disturbances at various periods diminished the trea-
sures of the Japan Palace. As it is, the Curator of
the Museum justly directs attention to it as a most
instructive part of the exhibition. “ In the room
called Bottcher’s room,” he says, “there are speci-
mens of the ancient porcelain, executed previously to
1763, made of the clay found at Meissen, red with-
out glaze; the red polished by lapidaries; the red
glazed; the iron-grey without polish or glaze; the
black glazed, in imitation of the Chinese; the earliest
blue and white, in imitation of the Nankin; then
the first white porcelain—the same painted with

colours; ilower vases and groups of Cupids, and
other exquisite productions; figures by Kandler; also
by the same artist two leopards of natural size, a
colossal bust of Augustus II., a concert of apes,
sixteen admirable figures, and various others of the
same description.”
The Museum at Sevres contains a collection of a,
very different kind from that of Dresden: its nature
and objects have been explained in a costly and bean-
tiful work, the title of which is given below.1 It is a
splendid collection, and is intended to illustrate the
potter’sart, and to reveal to the student all that has
been done up to the present day. The collection was
not made with a view to the study of beautiful forms
nor to the study of history or archaeology; but it
was made in order to illustrate in the completest
possible manner the history of the ceramic art. The
periods when certain pastes or glazes were introduced,
and the form of the vessel, its inscriptions and de-
corations, were only applied to the determination of
the state of the art among such a people and at such
a time. Bearing in mind the precise object of this
museum, we should prefer, say the authors, “ to
possess a Greek, Roman, Etruscan or Mexican vase
with certain defects which revealed to us the principles
of its fabrication, to a vase with inscriptions or orna-
ments capable of being turned to most instructive use
in illustrating the history of the people who pro-
duced it.”
It was not until the year 1812 that the museum
was arranged on its present basis by M. Brongniart.
At that period the collection of the establishment con-
sisted,—-1. Of the rich and interesting collection of
Greek vases procured by Louis XVI. about 1785, to
serve as models of simple and pure forms, and to correct
the bad taste into which the modellers had fallen during
the preceding reign; 2. Specimens of porcelain from
the works of Meissen, Berlin, Brunswick, Wurtemburg,
Vienna, 850.; 3. Specimens from various parts of France,
collected in consequence of a request on the part of
government that experiments should be made at
Sevres on the composition of coarse pottery and its
glazes, with a view to its improvement. It was
determined, in arranging this somewhat heterogeneous
collection, to distribute it so as to illustrate, 1. The
progress of the ceramic art from the manufacture of
a brick up to a piece of porcelain; 2. The geography
of the art, or specimens of the art as practised among
all nations; 3. The chronology of the art from the
most distant periods to the present time.
The objects in view thus clearly defined were made
public, and were carried out with so much success,
'that in the course of 30 years the present most in-
structive collection was brought together, either by
purchase of certain specimens, the exchanging of
duplicates or other forms of barter, but chiefly by
means of free contributions. In arranging the col-
lection, it was made a condition that every article,

(1) Description Méthodique du Musée Céramique de la Manu-
facture Royale de Porcelaine de Sevres, par M.M. A. Brongniart,
Administrateur, at D. Riocreux, Conservateur des Collections. Fol.
Paris, 1845; with 80 coloured lithographic plates.
POTTERY AND PORCELAIN.
4A3
every specimen of clay, silica or other material should
have a label written in oil colour containing concise
but suliicient particulars respecting it, and no article
was admitted until its appropriate label was prepared.
In this way articles of no value whatever without
their labels, became invested with a high degree of
technical interest when the name, the composition, the
origin, the locality, the date, the use, 860., were
attached to them.
To the evident utility of the collection thus
arranged M. Brongniart attributes its rapid increase
and success: about seven-eighths of the whole collec-
tion was presented by different individuals, among
whom captains in the French navy are conspicuous.
On their return from distant parts they were proud
to be able to present to this valuable museum some
specimen of pottery illustrative of the art as
practised in a remote corner of the globe. Our
English manufacturers have also contributed most
liberally to this collection, and while reading with
pleasure M. Brongniart’s candid and graceful acknow—
ledgment of their liberality, we could not repress the
feeling of regret that Great Britain does not possess
a similar collection.
The collection of raw materials used in the art is
very large and complete. It is not open to the
public, nor is it perhaps sufficiently attractive for the
purpose; but any student can gain access to it on
proper application. These specimens, furnished with
permanent labels, are arranged in drawers, above
which are cases containing the finished articles.
They are not classed according to their mineralogical,
nor even their technical, characters, but with special
reference to the manufacture to which they pertain.
In this part of the museum is a collection of tools,
implements, trial 'pieces, and articles which have a
purely historical interest, illustrating the progress
of the art. Thus there is the first article that was
made with kaolin after its discovery at Saint Yrieix
in 1765. There is also a collection of drawings and
plans of ovens, utensils, 850., used in different parts
of Europe.
The chronological arrangement of the specimens of
pottery and porcelain illustrates in a remarkable way
the progress of taste or the prevailing fashion. Thus in
accompanying artists and educated persons through
the museum, M. Brongniart thus refers to his own
experience :-—“ Between the years 1800 and 1815
persons of taste regarded as being beneath their
notice, below criticism, all the specimens of the art
which were produced between 17 410 and 1790. Taste
then suddenly took a different direction, and attached
itself to Greek forms, with more or less success ac-
cording to the merit of the artists who adopted them.
In 1815 there was again a sudden and violent change.
All these forms, all these groups, which but a few
years before had been regarded with such disgust
that I was compelled to pass as rapidly as possible
before the cases which contained them, to escape from
the odious criticisms which were poured upon them,
—-these same specimens now excited the highest ad-
miration, and were eagerly sought after by all who

pretended to taste or who professed it, such as artists
of distinction.”
There is yet another department of this interesting
museum, viz. a collection of failures! It was a
favourite remark of John Hunter, that the art of
surgery would not advance until professional men
had the courage to publish their failures as well as
their successes. We believe that this has been done
with much of the success that ‘was anticipated. At
Sevres specimens are preserved of raw materials with
the dated results of experiments upon them ; finished
articles showing the application of the data furnished
by these experiments, either in success or failure:
and secondly, specimens illustrating the methods
adopted to overcome the defects thus exhibited.
The peculiar value of such permanent records of
failure as well as success is self'evident—it marks the
progress of improvement and anticipates retrogres-
sion by showing what has been done and what it is
hopeless to attempt.
Regarding this museum as a whole, we quite agree
with M. Brongniart that it is eminently calculated
to illustrate the progress of the art. Scientific col-
lections have, or ought to have, a higher object than
merely to excite the curiosity and admiration of an
uninstructed public. Without neglecting the appeal
to the sense of the beautiful, the gratification of
that sense may be heightened indefinitely by combin-
ing with it the useful and the instructive. It is of
little importance to speak of progress in an art, unless
that progress is illustrated and rendered evident to
the eye. Books devoted to the subject do this very
imperfectly. The introduction of chromium into the
procelain manufacture, of uranium into stained glass,
&c., may be recorded in books on chemistry, but even
the manufacturer can have little or no idea of the
effects, except by the costly method of actual trial, or
by the inexpensive mode of inspecting the specimens
preserved in permanent and well arranged museums;
and it is only by the latter method that he can make
a practical study of his art as practised in different
ages and climes. At the museum of Sevres the
potter may in a few hours gain a precise idea of his
art as practised in the sixteenth century in China,
Germany, Flanders, &c., and then see how it is
practised in his own day in the same and in other
countries. We again ask, Why are not similar facilities
furnished to the English potter? The answer pro—
bably may be, that we have no Royal Porcelain-works,
and that we are accustomed to perform by private
enterprise many things which on the Continent are
undertaken by Governments. There is also probably
a feeling of pride which prevents us from imitating
the example of other nations. We prefer to do
things in our own way; and although they may “ do
these things better in France,” yet it may be a ques-
tion whether it would not be more in accordance with
our national habits to leave the conduct of industrial
education to our great manufacturers, than to attempt
to force upon the people institutions for which they
are not adapted. We should be sorry to slight the
attempts which are now being made to promote
4%
POTTERY AND PORCELAIN.
industrial education. We rejoice that increased faci-
lities for study are being afforded. Schools of design,
museums and courses of lectures are valuable uials to
study; if the people seek them with eagerness and
rapidly improve in them, the value of such institutions
will be demonstrated, and they will succeed, and
gradually adapt themselves to the wants of the
people and of the age. Our museums are at present
splendid examples of heterogeneousness, in which the
student is confused by the multitude of objects
before him, where the want of unity of purpose in
the collection is opposed to concentration of thought
in the student. The Museum of the School of Mines
is not free from this objection; although it has the
great merit of system, yet that system is too large, its
scope too wide. The Museum of Sevres appears to
us to be a perfect model of what this kind of institu-
tion ought to be, and it might, if the will only were
present, be carried out on a magnificent scale in the
manufacturing towns of Great Britain, each town
forming its own museum to illustrate the branch of
art or manufacture for which the town itself or the
neighbourhood is celebrated. Manchester might
collect into a historical series the various machines
that have been employed in the manufacture of cotton,
and also furnish specimens illustrative of the habits
and culture of the cotton plant. Sheflield would be
the representative of steel; the Potteries, of the
ceramic art; and so on. If each museum were
served by competent men, lectures given and a
journal published, the particular branch of manu-
facture thus illustrated would always be in advance.
Each museum would form a sort of focus in which
converging rays of knowledge from all parts of the
world would meet in order to diverge and diffuse the
light of intelligence around. That such a plan will
ever be carried out in this country is not likely. The
Great Exhibition contained the rich germs of a large
number of industrial museums, and we scattered to
the winds that noble collection, the most useful parts
of which might so easily have been retained. No;
we prefer to do things in our own way. We educate
our people to build steam-engines and to expend
power in vast mechanical enterprises; we keep the
hand of labour busily employed during six days of the
week, night and day, and grudge the seventh day’s
rest; there is little national feeling for a national
education of a higher kind : if we want taste, we send
to Paris or Italy to purchase it; and if the artist does
not supply us fast enough in his own country, we
purchase the artist himself, and he becomes an integral
portion of the factory.
Snorron IL-Marnnmns EMPLoYEDe—DIVISON or
- run Sumner.
The ceramic‘ art, in its widest sense, includes the
preparation of all articles in clay or argillaceous
matters, which are submitted to the action of fire;

(1) Ke’panog,pot_tcr’s clay, supposed by some to be derived from
Kepaivvupz, to mix up. Others derive it from Képas‘, an animal’s
horn, used as a drinking-cup. Others, again, suppose it to be
from 3pm, earth'. -

so that a comprehensive treatise on the subject would
include the manufacture of bricks and tiles, as well
as of the choicest specimens of pottery and porcelain.
The essential ingredients in every kind of clay,
and, consequently, in every article in pottery and
porcelain, are silica and alumina. [See CLAXZ] The
pure compound silieule of ulumiuu is, it is true, an
ideal type; since no clay, or artificially prepared pot-
tery or porcelain paste, is ever free from admixture
with other ingredients, such as iron, lime, potash, &c.
If, however, we remove from the paste either the
silica or the alumina, we render it useless for the
purposes of the potter; but by purging the paste of
the‘ accidental ingredients, the iron, lime, &c., we
exalt those properties which render it fit for the pre-
paration of fictile articles. An intimate mixture of
silica and alumina with water acquires, by exposure
to a high temperature, the required degrees of hard-
ness and density; but for many purposes it is neces—
sary to impart a certain degree of fusibility, to
which end other substances are used in various pro-
portions, capable of forming vitrifiable double sili-
cates with alumina and silica. These substances,
diffused through the paste formed by the simple
silicate of alumina, in some cases with silica in
excess, in others with excess of alumina, greatly con-
tribute to the cohesion and hardness of the mass.
The various mixtures employed in the different
branches of the manufacture, have been thus classified
by M. Dumas :-—
Silica, alumina Ideal type.
Silica, alumina, lime Earthenwares, crucibles,
Silica, alumina, oxide of iron............} bricks, tiles, encaustic
Silica, alumina, lime, oxide of iron"... tiles and comnmn pottery.
Silica, alumina, potash Hard porcelain.
Silica, alumina, soda . Soft porcelain.
Silica, alumina, magnesia.............. Piedmont porcelain.
Silica, alumina, baryta Stoneware.
The terms soy‘? and Aural as applied to POTTERY, or,
as the French name them, tenure and clue‘, have refer-
ence, not only to the composition, but also to the
degree of heat to which the ware is exposed in the
furnace. Thus common brick is soft, fine brick is
hard. Common earthenware vessels, such as pipkins,
flower-pots, &c., are soft; while crockery, such as
Queen’s ware and stone ware, is hard. Soft pottery,
named by the French, fayeuee 2 d pa’le z‘eurlre, is the
most ancient. Soft pottery, composed of silica,
alumina, and lime, is generally fusible at the heat at
which porcelain is baked. It can be scratched with
a knife or file. Four kinds of pottery are distin-
guished by collectors, viz.—-1. the uuglazeel, 2. the
lusli'ous, 3. the glazed, and 41 the euumelleal. The
first three comprise the ancient pottery of Egypt,
Greece, and Home, as well as the more modern in
common use among all nations. The enamelled is
covered with a thick vitreous enamel, capable of
being ornamented with paintings of great delicacy
and beauty. The Majolica, or enamelled pottery of
Italy, is of this kind.

(2) The word fuyence, or faz'ence, is an old French term for all
descriptions of glazed earthenware, even including porcelain. It
corresponds in general use to the English word, crockery.
POTTERY AND PORCELAIN.
‘M5
The terms hard and soft are also applied to Ponce-
LAIN, and ‘they may be distinguished by applying the
point of a knife, which will scratch the soft, but
will make no impression on the hard. Thehard kind
contains a greater portion of alumina, and less silica ;
it is exposed to a greater heat, and has a greater
density than the soft. Soft porcelain contains a
larger proportion of silica, together with alkaline
fluxes; it bears a less heat, and is less dense than
the hard. It is, in fact, soft in two senses, in being
less .able to resist a high temperature, and in being
easily scratched by a knife. Réaumur endeavoured
to produce porcelain by means of hardening and
giving opacity to glass. [See GLASS, Sec. 11.]
Bottcher succeeded in making hard porcelain, by
softening pottery, and rendering it translucent. In
fact, porcelain may be considered as a substance
intermediate between pottery and glass.
After the article formed in clay has passed through
the fire it becomes converted into a porous substance
termed biscuit, and it is rendered impermeable to
water and durable under wear by means of glazing or
glassz'ng, z‘. a. covering the surfaces of the biscuit with
a thin layer of glass. For fine wares, such as porce-
lain, the vitreous glaze has a close analogy to the
substance of the paste itself; it is not very fusible,
but yet must melt at a lower temperature than the
article which it is destined to cover and protect. The
glaze incorporates itself so completely with the his-
cuit, that on breaking a piece of well-prepared porce-
lain it is impossible to mark the line of separation
between the biscuit and the glaze. A very high tem-
perature is required to produce this effect. The glazes
for pottery are much more fusible.
The materials for porcelain are selected and pre—
pared with so much care that the biscuit, on leaving
the kiln, is colourless: the glazes also are selected of
such materials as will form a pure transparent glass.
The clays which are used for pottery-ware being im-
pure, and frequently containing protoxide of iron, the
latter is converted, by the oxidizing influence of the
flame, into a peroxide, which colours the clay red.
This red colour of the biscuit is concealed by an
Opaque glaze, or by communicating a deep colour to
transparent glazes. The pottery glazes do not com-
bine with the biscuit, but form a distinct layer on its
surface. Coarse potteries are glazed on one firing
only, for which purpose, while they are at a very high
temperature, a quantity of moist salt (chloride of
sodium) is- thrown into the kiln: the salt is volati-
lized and decomposed in the presence of moisture,
and in contact with the heated surfaces of the clay:
hydrochloric acid is disengaged, and the articles be-
come covered with silicate of soda, which, combining
with the silicate of alumina (the clay), forms a very
fusible double alkaline silicate or glaze on the surface
of the articles.
It is remarkable that nearly all the products of the
potter’s art have, in all ages, and among allpeople, been
deemed incomplete without the addition of an orna-
ment of some kind not required in the use of the arti-
cle ornamented, but simply for the purpose of pleasing

the eye. The very plastic-and impressible nature of
the material doubtless offers considerable facilities
for the purpose, and in many examples of the un-
glazed pottery of rude nations, in addition to great
beauty of form, simple ornaments have been added
with exquisite taste; such as straight or flowing
lines impressed with a point; equidistant indentations,
or elevations ; and in proportion as a people becomes
refined, the ornaments become more elaborate, if not
more beautiful. The ornaments on pottery and por-
celain, which depend on colour, are afforded by gold
and platinum, or by metallic oxides capable of fur-
nishing coloured silicates unalterable in the fire. In
the ornamentation of porcelain the skill of the artist,
and the science of the chemist, have been exerted to
the utmost; although it may fairly be questioned
whether works of high art are properly represented
on so fragile a material as porcelain, considering the
great difficulties of the art and the large number of
precautions required.
In order to lay before the reader as full an account
of the theory and practice of the ceramic art as
our limits will allow, we propose to follow an upward
course, commencing with the preparation of articles
in which the crude material undergoes very little pre-
paration, until we arrive at the finer kinds of ware,
the materials for which are prepared with the greatest
care, and the ornamentation and glazing of which
require much skill.
Sncrron HI.-—-MANUFACTUBE or Coansn Porrnnr.
The manufacture of bricks and tiles offers an ex-
ample of the lowest application of the potter’s art.
We have already devoted an article to the manufac-
ture of bricks, [see Bureau] and have now to notice
the method of making tiles.
The clay used for making tiles is purer and stronger
than that employed in brick-making. In order to
open the pores of the clay and separate the particles
so that it may absorb water and work freely, the
clay is exposed to the weather. The weathering is
performed by spijeading it out in thin layers about 2
inches in thickness, ‘andexposing it to at least one
night’s frost, or to the scorching heat of a summer's
sun, before another layer is put on. In very cold or
very hot weather the layers may be 4: inches thick.
The weathered clay is thrown into pits, and left
covered with water for a considerable time, to mellow
or ripen. Before being used it is tempered by being
passed through the pug-mill. The pug-mill here used
differs from that described under BRICK, Fig. 235, for
instead of being conical it is made to taper at both
ends, and the ejectment hole is at the bottom instead
of in the front. If the clay be very foul, or full of
stones, it is slung; that is, as the clay issues from the
pug-mill it is cut into lengths of about 2 feet with a
sling, or wire-knife, consisting of a piece of wire with
two handles, shown in Fig. 1677. The slingers cut
up these lumps into slices not above % inch thick,
during which the stones fall out or are picked out by
hand. The clay is then passed again through the
pug-mill, and is ready for the moulder. For chimney-
4A6
POTTERY AND PORCELAIN.
pots and similar articles the clay is slung once or
twice, and pugged or ground, as it is called, two or
three times. Insome parts of England the stones
are separated from the clay by sifting, and the
tempering is done by treading, an operation noticed
under IRON, Fig. M26, when describing the mode of
making the clay crucibles for cast-steel.
The clay as it issues from the mill the last time is
cut into lumps or pieces, which are stacked on a rough
bench; these are cut by a labourer into half-pieces,
and wheeled one by one to the pan-tile table.
We may here remark that tiles are of three classes,
viz. paving tiles, roof tiles, and drain tiles. Paving
tiles may be considered as thin bricks. Roofing tiles
consist of Pantiles, which are curved so as to form
with each other a water-tight joint; and gilaintz'les,
which are flat. These were formerly made with holes
in them for the reception of the tile pins, by which
they were hung on the laths, but it is now usual to
turn down a couple of nibs on the head of the tile,
which serve instead. Pantiles are moulded flat, and
afterwards bent into shape on a mould; as is also the
case with M12, and ridge and valley tiles.
The pmztile table or moulding table, Fig. 1675, is
placed under a shed, which also shelters the bloc/rs
or drying shelves on which the tiles are placed as
they are formed. Each shelf is formed with three
l-inch planks placed edge to edge, and separated from
each other by bricks placed edgewise; each block

contains about 14¢ shelves. The moulding table con-
tains a trzzg or trough a, into which the moulder dips
' his hands when moulding,
and a block and stools-board
j; on which the tile-mould
is placed during the mould-
ing. They form one piece,
which is keyed to the
moulding table by a tenon
2.‘, Fig. 167 6, on the under
side of the block passing
through a mortise m in
the table. Four pegs pp,
Fig. 1675, driven into the


F ig. 1676.
table at the corners of the block and stock-board,
support the mould and regulate the thickness of the
tile, which for a pantile is %ths of an inch. The tile-
mould, sling and wooden roller are shown inFig. 1677 :
the process of moulding is thus described by Mr.

Dobson :—-“A rough moulder, generally a boy, takes
the half-piece and squares it up, that is, beats it up into


Fig. 1677.
a slab near the shape of the mould and about 4 inches
thick, from which he cuts off a thin slice, the size of a
tile, and passes it to the moulder. The moulder having
sanded his stock-board and placed his mould on the
41 pegs which regulate the thickness of the tile, takes
the slice of clay from the rough moulder and puts it
upon the mould. He then, with very wet hands,
smooths the surface, cutting off the superfluous clay
with his hands in long pieces called strippings (s t,
Fig. 1675,) which are thrown to a corner of the table.
This done he stirkes the surface level with the roll;
and turning the tile out of the mould on the washing
off frame, (f;
Fig.1678,)with
very wet hands
washes it into
a curved shape.
He then strikes
it smartly with
the splager s,
Fig. 1679, and
turns it over on
that implement,
on which he
conveys it to the block, where he deposits the tile with


s .
Fig. 1678.


Fig. 1679.
the convex side uppermost, and the splayer being
withdrawn the tile is left to dry. The button end
of the tile is placed inside the block. The tiles
remain in the block until they are half dry, when
they are taken out one by one, placed on the thwack-
ing frame, Fig. 1680, and beaten with the thwacker t,
Fig. 1679, to perfect their shape. The wing of each
tile is then trimmed with the thwacking knife 7:, Fig.
1679, and the tiles replaced in the block still with
the convex side uppermost; but this time the button
(1) “On the Manufacture of Bricks and Tiles,” published in
Weale’s Rudimentary Series.
_ POTTERY AND POROEIIAIIV. *
4157
end is placed outside. The tiles then remain in the
block until ready for kilning.” The tiles flatten


.fli
;lllll
ll
r§~|
.
f a"
‘r


' 11;
av" ‘
u lll Fig. 1680.
slightly in the block, and hence the washing off frame
is made a little more convex than the thwacking
frame, the latter corresponding to the permanent form
of the tile.
At Basford, in Staffordshire, where there is an ex-
tensive hill of good marls, tiles are made in the
following manner :-—The mould is 12 inches by 7%
inches, and i— of an inch thick, and is made of oak
plated with iron. The moulder at his bench works a
lump of clay into an oblong square somewhat less
than the mould: the mould M, Fig. 1681, being placed
on the bench,
fine coal- dust
(I " is thrown into
it from the box
0 ; the lump
of clay is then
dashed down
into the mould
with consider-
able force, and the surplus clay is cut off level with the
‘mould by means of a brass wire strained upon awooden
bow B ; the lump is then removed, and the clay left in
the mould finished by adding a little clay if it be
wanted, and smoothing it over with a wooden rod.
Two thin boards about the size of the moulded tile
are dusted over with coal-dust; upon one of these the
moulded tile taken out of the mould is placed, the half
circular projections extending beyond the board. In
this way one man moulds from 1300 to 1500 tiles per
day. A boy carries away 2 tiles at a time to the floor;
he takes up one on the board, and by the thick part
of the hand presses up the two projections at right
angles with the face of the tile, and then places the
board and tile on his head, and, his hands being thus
at liberty, he operates on the second in like manner,
while walking to the floor, where he deposits the two
tiles, and carries the boards back to the moulding-
bench. The tiles are left on the floor about ‘is hours:
they are then collected and placed close together, the
nib end changed alternately, to allow them to rest
close and square; in this state they are walled up in
:a dry situation, and left for a day or two. The sez.‘
.or curved form is given to them by means of a lime
h, Fig. 1582, or three-legged stool, the top of which


is a little larger than the tile, and is curved one way
to about a 10 feet ra-
dius. There is also
a wooden block b,
curved to correspond
with the surface of
the horse. Six tiles 2.‘
are put on this horse,
the man then lifts
the wooden block,
and gives them three
sharp blows with it: they are next taken away, and
built up with other similar tiles into the kind of wall
shown in Fig. 1683, to dry; the courses being sepa-
\\//._ 1
"
"Wr- )1’; ..'- “


Fig. 1682.
Fig. 1683.
rated from each other by laths ZZ, two to each course.
After this the tiles are ready for firing.
Fig. 1684b is a section of a portion of a London tile-
kiln; it has arched furnaces enclosed in a conical


§—.
is."
74-.
r. \\
I.
k
“=5

Fig. 1684.
building called a dome. The whole of the furnace
and body of the kiln is of _ fire-brick, and the
arrows mark the direction of the fines. In setting
the kiln, a course of vitrified bricks is laid at the
bottom, herring-bone fashion, 1% inches apart. On
this course the tiles are stacked as closely as they
will lie, in an upright position, one course above
another. As the body of the kiln is filled, the hatch-
ways are bricked up with old bricks, and when the
kiln is topped, they are plastered over with loam or
clay.- The top is then covered with a course of un-
burnt tiles, placed flat, and lastly with a course of old
pantiles loosely laid. The fires are lighted on Mon day
M8
POTTERY AND PORCELAIN.
'table as before.
'of the cylinder, the action ‘of the rack is reversed,
' whereby the'plunger is drawn up out of the cylinder.‘
‘The cylinder, which moves on a kind of hinge, is then
tilted on one side to receive its charge of clay, and'
morning, and not put out until Saturday night. About
8 tons of coal are consumed at each burning.
The London tileries also make drain-tiles, drain-
pipes, chimney-pots, garden-pots, and various other
articles. The large and increasing demand for
draining tiles and pipes, has led to great economy ~in:
their manufacture.
wards bent round a wooden core to ‘the proper shape :‘
others are made at once of a curved form by forcing
the clay through a deal or
mould, Fig.1685, by me-
chanical pressure. The
action will be readily un-
derstood from Fig. 1686,
which represents a sec-
tion of a strong iron cy-











:2:
Q '__ linder, containing a quan-
l l'i \ tity of clay in the act of
being pressed down with
enormous force by a solid
1; ' ’ piston or plunger. The
3‘- 1 .////l é clay as it escapes through
. " the dod is evidently
% ‘ moulded into the form of
AL the pipe, (also shown in
t section,) which is cut off
in lengths,-by means of
a wire, and these, after
a preliminary drying, are
ready for firing. By
using dods of different
sizes, pipes of various magnitudes are formed.
Fig. 1687 is an elevation of a drain-pipe making
machine, which we have copied from Mr. Green’s
works at Lambeth.~ The cylinder contains a second
cylinder, capable of holding a given weight of clay,
adapted -to the moulding of a certain number of pipes
at one charge. Thus, one bozrfull will furnish five
9-inch pipes, six 6-inch pipes, seven 41-inch pipes, and
so on. By the action of the rack the piston forces
the clay through the dod or die upon a table, so
balanced by weights that the lengthening pipe is
suificient by its weight to force down the table, and
when a certain length of pipe is formed, the boy
stops the machine by shifting the strap which drives
the rack-screw from the fast to the loose pulley,
and then cuts off the length of pipe with a wire, re-
moves the pipe so formed, raises up the table, sets
the machine in action, and receives a’ pipe upon the‘
When all the clay is thus forced out‘
being restored to its vertical position, the action pro-
ceeds asbefore. By an ingenious contrivance,‘ the
‘fork which shifts the strap from the fast to the loose
pulley is weighted in such a manner ‘that when the
boy raises his foot from a treadle, the strap is at once.
moved on to the loose pulley, and vice ceijsu‘,‘ thus
giving the attendant a third hand, and diminishing
the chances of danger from the strap. Mr. Green
Some are moulded flat, and after-i

has a machine worked by a screw, in which the pro-
cess is continuous. These pipes are washed with
glaze before the firing, as will be explained hereafter.













u \


/ "Lies; l
s " . all. ;/
2/ ~. ‘4 ,
' " that liq-‘fr




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v ' ,5 '
.; . ‘
4\
\ \u'n'" ' ‘I’ \
\ \\\
._ i':;_‘ 1 s-" 7 h“
twill.



Fig. 1687.
DRAIN-PIPE MAKING MACHINE.
By means of a tile-machine, the hollow bricks are
formed, which are so much recommended by the
“ Society for Improving the Condition of the Labour-
ing Classes,” and introduced by them in the con-
struction of dwelling-houses for the poor. The idea
of tubular bricks is not new, for such articles were
used by the Romans in large vaultings, where
lightness of construction was required, and they are
aid to be in common use in Tunis at the present
time. The size of the bricks is 12 inches long, and
three courses rise 1 foot in height, 9 hollow bricks
twill do as much walling as 16~ of the common ‘sort,
with only a slight increase in weight. In passing
through the tile-machine, or in the process of drying,
the bricks can be splayed at the ends for gables, or
marked for closures, and broken ofi as required in
‘use, or they'may be perforated for the purpose of
ventilation. If nicked with a sharp-pointed hammer,
they will break off at any desired line; and the
vangles may be taken off with a trowel as in the
common brick. The bricks for the quoins and jambs
may be made solid or perforated, and with perpendi—
cular holes, either circular, square, or octagonal:
those in‘the quoins may be so arranged as to serve
for ventilating shafts. The hollow bricks, from their
mode of manufacture, are more compressed than
. POTTERY AND PORCELAIN.
449
common bricks, require less drying, and are better
burned with less fuel. . . .
The following figures represent some of the forms
of hollow bricks in common use. a, Fig-1688,1'S
an external brick 11%,— inches long, which with the
quota brick e, and the jamb brick, b, are sufficient for
building 9-inch walls. e is 10% inches long, with one
splaycd corner for forming external angles, reveals,
and'jambs‘ of doors ‘and “windows either square or















Fag. 1688.
splayed. The internal jamb and c/zz'mrzeg/ brick, b, is
8% inches long; a is an internal brick adapted to any
thickness of wall beyond 9 inches: at is for 5% inch
partitions, or internal walls, and arch bricks, and is
used for floor and roof arches of 7 to 10 feet span. fis
used for the same purpose, with a webb' to give extra
strength and to adapt them for using on edges in
partitions, 3% inch thick to rise in 6-inch courses.
Fig. 1 689 represents a
specimen of hollow brick
work in (5-inch courses,
with square rebated
joints for extra strength.
Those bricks are adap-
ted to the lining of
flint or concrete walls.
Fig. 1690 is a section
illustrative of the con-
struction adopted in
H.R.H. PrinceAlbert’s
model houses. The
span of the arches is in-
creased over the living
rooms to 10 feet 4.
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Fig. 1690.
VOL. II.

inches, with a proportionate addition to their rise.
The external springers are of cast-iron connected by
wrought-iron tie rods.
It is stated that there is an advantage of 29 per
cent. in favour of the patent bonded hollow bricks
over ordinary bricks, in addition to a considerable
diminution in the cost of carriage or transport, and
of 25 per cent. on the mortar and the labour.
Among the articles in coarse pottery, which excited
considerable attention in the Great Exhibition, were
the gas retorts of fire-clay exhibited by Messrs.
Joseph Oowen & (30., of Blaydon Burn, near New-
castle-on-Tyne. About 20 years ago each retort was
made by Messrs. Cowen in 10 pieces; this number
was reduced to 4.‘, 3 and 2, until in 184A: the retort
was made complete in one piece. The largest dimen-
sions are 10 feet long by 3 feet internal width.
Mr. Lowe, the gas-engineer, remarks, with reference
to these retorts and the fire-bricks manufactured by
the same firm, “ One especial feature in these bricks
and retorts visible to the eye, and so essential to their
withstanding high heats, is their freedom from iron,
which acts the part of a flux, destroying the other-
wise good properties of many fire-clays. This he
arrives at by following the Chinese practice of sub-
mitting his clay for years exposed to all weathers,
turning it frequently over, whilst young hands pick
out the fossiliferous fragments, generally pyritous,
which this disintegrating process lays open to ObSfiI'“.
vation. The clay contains a high per centage of silica.
Add to these points great care in the manufactory, in
which every appliance is to be seen, and we have nearly
the secret of Mr. Oowen’s fame. He has testimonials
from all quarters, one from Rouen, stating 38 months
as the durability of some of his retorts, being 41 times
that of iron ones.” Messrs. Cowen obtain their clay
from no less than 9 different seams, so that they are
able to mix their clays extensively to suit different
purposes.
Fire-clay is found in England in the coal-measures,
but it differs considerably in different districts. It is
refractory, i.e. resists the action of fire, in proportion
to its freedom from alkaline earths and iron, which
render the clay fusible at high temperatures. The
proportions of silica and alumina in these clays vary
considerably, the silica from 50 to 7 0 per cent, and
the miscellaneous ingredients from 1% to upwards of
7 per cent. The celebrated ,S'toztrbrz'clge clay consists
of silica 63‘7, alumina 22'7, oxide of iron 20, and
water 10 8 per cent. This clay lies about 15 feet
beneath the lowest of 3 workable seams of coal,
worked at Stourbridge, in the lower coal measures in
the north-western extremity of the Dudley coal-field.
The bed of clay is 4: feet thick. Some of the fire
clays of other parts of England are now admitted to
be nearly, if not quite equal to this.
SECTION IV.—Manuraorunn or Tonacco-rrrrs.
THE manufacture of tobacco~pipes is a branch of
the potter’s art which derives importance from the im-
mense demand for those small contrivances. Those
who do not indulge in the use of tobacco may despise
' c e
4150
POTTERY AND PORCELAIN.
a manufacture which ministers in no way to their
wants, but rather excites their disgust. There might
have been something of this self-satisfied feeling
in the ancient Greek philosopher, who in passing
through the fair at Athens, and seeing the shops
filled with so large a variety of wares, exclaimed
with a smile, “ How many things are there that I do
not want 1” We too may smile at, and yet admire the
large amount of science, energy, capital, and skill
which are applied to meet a want as soon as it is
generally'expressed, or to gratify a whim or a caprice
which may have become fashionable.
In the manufacture of tobacco-pipes there is much
to admire. The pipe itself is an ingenious con-
trivance: the bowl is a kind of furnace in which
tobacco is burnt; the chimney to this furnace is a
long perforated stem, and the draught is excited by
the lips of the smoker drawing air through the bowl :
this supplies the ignited tobacco with fresh oxygen,
and the products of combustion, consisting chiefly of
nitrogen, carbonic acid, and oil of tobacco in avolatile
form pass up the stem into the mouth of the smoker:
the length of the stem cools the smoke, and deposits
a considerable portion of the poisonous oil which is
absorbed by the porous clay of the pipe, while the
ashes, consisting of salts of potash, lime, &c., remain
behind in the bowl. The comfort of the smoker is
further consulted by the curve given to the stem, the
. effect of which in holding the pipe is always to main-
tain the bowl in its right position, while the small
projection below the bowl serves as a guide in holding
the pipe, or in passing the fingers down towards the
heated part. There. are many forms of clay pipe,
but perhaps the best is that known as the old corpo-
ration pipe: it has a long stem, a large bowl, and a
smooth surface, with a very slight yellow tint.
The clay employed in this manufacture occurs in
the island of Purbeck in Dorse'tshire, and in several
parts of Europe, the lower' portions of the deposits
being most esteemed. The clay is carefully purified
from foreign matters by some of the usual mecha-
nical processes, and is formed into cubical masses
of from 80 to 1001b. each. From one such mass
the moulder cuts off a number of lumps, each suf-
ficient for one pipe, kneads them upon a table, and
rolls them out nearly to the form and dimensions of
the intended pipe, leaving a bulbous portion at the
end for the bowl. When these rolls have become
somewhat hardened by exposure to the air, they are
bored by means of a wire mounted in a wooden
handle: the man holds the roll between the three
fingers and thumb of the left hand, and guides the
wire very accurately by touch along the axis of the
roll. The wire is slightly enlarged near the end, and
this assists the operation. The roll thus impaled,


Fig. 1691.
his 1691, is placed in the groove of one half of a
copper mould, Fig. 1692, slightly brushed with oil in
order that the stem may be smoothly delivered. The


other half of the mould exactly fits by means of pins
and hollows which correspond in the two halves.



Fig. 1692.
The mould is next placed in an iron frame, Fig. 1693,




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I ‘if’: -‘i -' '~ ‘- ~
l ‘ i‘tél ll [in ’
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1 _._l

and its two parts are forced into close contact by
means of nuts and screws. The clay of the stem is
thus made to assume the form of the mould, together
with any letters or ornaments which have been cut in
the mould. The bowl is formed first roughly by the
finger, and then by forcing into the
mould the plug, Fig. 1694‘, which
is held by its cross handle, while
the rim determines the size of the
cavity of the bowl. The bore of
the stem is then continued until
the wire touches the plug, but
_ there is a small pellet of clay
Fm’ 1694' which precedes the wire, and this
requires to be removed by a little hook attached to
the handle of a kind of knife, with which the pipe,
now removed from the mould, is finished by cutting
away superfluous morsels of clay, &c. The top rim
of the bowl is finished by a small copper mould, Fig.
1695. Ornaments which are not
given by the pipe mould are now
‘ added by means of small rollers
and stamps. Boughnesses are
rubbed away by a small grooved
iron tool, and polish is given by
grooved agates. The pipes are
next arranged in shallow trays, and left for some
time to dry.
Notwithstanding the number of processes which
each pipe has to go through, a good moulder will pro-
duce 500 pipes a day.
In baking the pipes they are arranged in crucibles
or seggars of pipe clay, strengthened by the insertion
of broken pipe stems. The bottoms are framed of
these stems radiating towards the centre, and the
interstices are plastered with clay. The top of each
is dome shaped, and a pillar of clay is placed in the
centre through the whole height, for the purpose of
strengthening the crucible and also of supporting the
stems of the pipes. Each crucible is provided with
six horizontal ledges running round the interior at
equal distances : these support the bowls of the pipes,
while the central pillar supports the stems. See Fig.
1696. As many as 50 gross of pipes can be arranged
in one crucible. The crucibles are placed in a cylin-


Fig. 1695.
POTTERY AND PORCELAIN.
4151
drical kiln, Fig. 1696, with a circular fireplace at the
bottom.
The pipes should
be of a fine white
colour after the
firing, and such
clay only is in ge-
neral selected as
will produce that
colour. It hap-
pens, however, in
certain localities


that clay, in other
respects of 'excel-
lent quality, be-
comes red in the firing, in consequence of the minute
portion of oxide of iron contained in it becoming
converted into the red peroxide under the influence
of the oxidizing flame. The pipes come out of the
kiln of a reddish hue. This defect has been reme-
died in an ingenious manner by the deoxidizing
influence of carbon; for which purpose the kiln,
when in full action, has its chimney and all other
openings closed for about three quarters of an hour,
the effect of which is to condense the smoke of the
fuel upon the pipes in the form of soot. The holes
are then unstopped and the fire urged for a quarter
of an hour, the effect of which is to raise the pipes
to a red heat and burn off the soot or carbon. This
operation is repeated several times according to ex-
perience, but the last time the fire is urged for an
hour. The effect of this treatment is to convert the
red peroxide of iron into the pale green protoxide,
which scarcely interferes with the white lustre of the
pipes, except just within the bowl, which remains
slightly red.1
By a somewhat similar process an opposite result
is obtained, viz. the production of bloc/r: pipes. The
seggars containing the pipes are partly filled with
oak sawdust, and placed in the upper part of the kiln
where the heat is least. The carbon of the wood
thus combines with the clay, and as it is not burnt
off by exposure to air at a high temperature, the
pipes come out of the kiln of a dull black colour:
they are polished by being dusted with plumbago
and then rubbed hard with a cloth.
Baked clay has so strong an affinity for water [see
ALUMINA], that when a new pipe is put into the
mouth it absorbs the moisture from the lips, and
adheres to the skin with such force that if suddenly
detached it might tear away the skin. We have
heard of such a case, and of a dangerous wound being
produced thereby. The usual remedy is to tip the
end of the pipe with sealing-wax, but a better plan is
Fig. 1696.

(1) This method was communicated in 1730 by a manufacturer
of St. Omer to Duhamel du Monceau, whose treatise on the manu-
facture of pipes written for the celebrated treatises on “Arts et
Métiers,” of the Academy of Sciences has served as the text for
most writers on this subject up to the present day. It is some
encouragement to the Editor to pursue his laborious task, when
he finds such men as Réaumur and Duhamel devoting their time
and splendid talents to the preparation of elaborate treatises on
the Useful Arts.

to polish the pipes by dipping them into a mixture of
fat clay and water, and then polishing off with flannel.
For the better kinds of pipes a sort of varnish is
made by boiling soap, wax, and gum in water, and
applying it by means of a flannel with friction.
The bowls of tobacco pipes are also made of pro-
celain, and highly ornamented. This is an example
of pressed ware and of painting on porcelain, and
calls for no special remark. Memes/mum pipes are
noticed under MAGNESIUM.
SncrIoN V.——PREPARATION or THE MATERIALS FOR
POTTERY AND PORCELAIN.
Pure clay tempered with water forms a very plastic
paste, capable of being easily worked. It is exceedingly
impressible, and assumes any form which the fingers
of the potter may impart to it. The sensitiveness of
this material may be illustrated by stamping a seal
upon a lump of clay, drying the lump and carefully
paring off all traces of the impression; if the lump be
now passed through the kiln the impression of the
seal will be revived, thus showing that the molecules
of the clay had received and retained the impression
to a considerable depth below the surfaces.
But this sensitive plasticity of clay, which so
admirably adapts it to the shaping of vessels and
other articles, leads to some inconvenience in the
firing; for the clay undergoes so large an amount of
contraction by heat that thin wares become distorted,
and are also liable to crack. And this distortion is
not altogether due to contraction or to the unequal
evaporation of the water: it is also occasioned by the
tendency of the aluminous particles to return to their
normal position, from which they were slightly dis-
turbed in the process of throwing or turning on the
potter’s wheel. In this process the clay is spun upon
a vertical lathe, and moulded by the pressure of the
hand into continuous bands, spirally disposed, passing
from right to left, from the base of the vessel to the
summit. When such a vessed is raised to a high
temperature the particles thus disturbed and the
points thus compressed tend to return back to their
normal position of equilibrium, as may be easily
proved by marking upon the vessel, before it is fired,
two points in a vertical line, when it will be found
after the firing that these two points are no longer in
the same vertical; the lower point will have moved
more towards the right than the other, and this is so
well known to the workmen, that on attaching handles
to cups, jugs, &c., before the firing, they are ac-
customed to place them a little askew, and the distor—
tion produced by the contraction in firing restores
them to their vertical position.
This remarkable plasticity of clay is lowered down
by the addition of a substance which does not possess
that property in the slightest degree, viz. silica. This
substance is prepared from flints, quartzose sands,
felspar, &c., but these are not the only nonplastic
materials employed; for chalk, sulphate of baryta and
calcined bones are used with good effect.
In the manufacture of earthenware two principal
ingredients are employed, clay and flint‘. The nature
a e 2
452
Por'rnnr AND Pon'onnain‘;
I celain.
,-
and proportions of these rest with the manufacturer,
and upon the soundness of his judgment in these
respects, more than in any peculiar art of construction,
depends the excellence of his ware. The clays com-
monly used in the Staifordshire potteries are brought
from Devonshire and Dorsetshire, ln'owu and blue clays
from the latter, blue/e and cracking clays from the
former. The black clay owes its’cblourfto'the pre-
scncefof bitumen or coaly‘matter, but t‘his‘disappears
in passing through theI‘pQtter’S ov'en,'~“"s_'ci"that “the
wares formed of it are—nearly; white. I clay
is valuable for its pure white‘colounfiiiitis'liable to
crack during the first burning, and-'i'inust‘tlierefore be
in
mixed with other clays which have notlthisi-thndeifciy.
Brown clay is also liable to an imperfection ‘sauna ,
cruziug or cracking of the glaze. Blue clay isithe
best for ordinary purposes; it will bear a larger pro-
portion of flint than the others, and therefore produces ‘~
a whiter ware. For the finer kinds of earthenware,
a fifth variety, being the claim clay of Cornwall, is
largely employed. This consists of felspar, one of the
ingredients of granite, in a partially decomposed
state. It is collected in the following manner :—The
stone is first broken up with a pick-axe, and thrown
into a stream of running water. ' This washes off the
argillaceous parts, and keeps them suspended while the
quartz and the mica (theother two ingredients of gra-
nite) sink at once to the bottom. At- the end of these
rivulets the water is dammed up, forming what are
called cuielipools, and here the' pure clay subsides in
a solid mass, which is afterwards dug out in blocks,
(the water being drawn off,) and laid on connected
series of strong shelves, called liuuees, to dry. It is
then crushed, packed in casks, and sent to the pot-
teries as c/u'uu eluy. In this stateit is a white im-
palpahle powder, consisting of 60 parts- alumina, and
‘20 silica. A certain proportion of undecomposed
felspar is often added, as it serves to bind the ingre-
dients more closely together. Neither clay, flint, nor
lime can be melted separately in the greatest heat of
a porcelain furnace, yet when mixed together in
proper proportions one mineral acts as a flux to the
others, and the mass can be fused without diificulty.
Flints for the manufacture are obtained from the
chalk districts, chiefly of Gravesend and Newhaven.
They are white externally, but dark and clear within.
When the fracture exhibits yellow spots, the flint
must be rejected as containing iron which would stain
the ware. Steatite or soapstone occasionally forms
one of the ingredients in the manufacture'of por-
There is a mineral called pegmulile, inwhich all the
materials for hard porcelain exist ready mixed. Peg-
matite consists of felspar, kaolin, and a small quantity
of prismatic quartz, the last being valuable for the
whiteness and transparency which it imparts. There—
fore a good pegmatite, well decomposed, is all that
the manufacturer requires. Soft porcelain, as it is
manufactured at the present day, consists of two in-
gredients from the mineral kingdom, and one from
the animal kingdom, viz. kaolin, Cornish stone, and
bones. The last melt into “ asort of semi-transpa-

rent enamel,” which gives transparency to the .'por-
celain according‘ to the quantity used. . .
The preparation 'of these materials involves many
processes and much labour and care. The first pro-
cess is'the mixing of the clay, and is called bluugiug.
The proper proportions of blue and white clay are
placed overnight in a trough about two and a half
feet deep, with the needful quantity of pure water.
In- the morning these are well incorporated with the
,water by means of a long blade of ashwood with
Ilaicross handle at its upper extremity, called a bluugei-
;or' plunger. This is worked violently in the trough
a smooth pulp is obtained, a pint of which
is; the addition of water, made to weigh 21L
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Fig. 1697.


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BLUNGING.
ounces, but when china-clay is used, a pint is made
to weigh 26 ounces. To facilitate the blunging pro-
cess, the clay is sometimes pugged in a cast-iron cy-
linder, 4: feet deep and 20 inches in diameter, through
the centre of which runs an upright shaft furnished
with a spiral line of knives inclining downwards:
A corresponding series of knives is fixed to the inside
of the cylinder, so that as the shaft revolves the knives
cut up the clay, and by their inclination force it down-
wards. In its divided state it then passes through
an opening in the bottom of the cylinder, whence it
is removed to a vat, mixed with water, and blunged
by means of a perpendicular shaft furnished with
cross-arms. During the revolution of the shaft, the
finer particles of the clay mix with the water, and the
stony substances which may be present sink to the
bottom.
The preparation of the flints involves several pro-
cesses. They are first burnt in a kiln for about
80 hours, and either thrown into cold water while
red-hot (which greatly increases their brittleness), or
allowed to cool before being taken out. They are
next placed on a strong iron grating, and acted upon
by powerful stampers, or wooden beams shod with
iron, Fig. 1698. These reduce the flints into fragments
sulficiently small to pass through the grating. These
fragments'are conveyed to the fiiul-puu, Fig-1599,
consisting of a strong circular vat, 10 or 12 feet in
diameter, the bottom of which is formed of quartz or
felspar in small blocks, imbedded in ‘mortar of. a
similar composition to the material which is to he
,POTTE RY AND PORCELAIN. .
453
‘ground. In the centre of the vat is an upright shaft,
surrounded by a barrel or hoop, 14 inches high,
_\-n__r__....fl g
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Fig. 1698.
to prevent the materials from being soiled by the
moving power while being ground. From the central
shaft project it strong frames, which move the run-
ners, consisting of very hard siliceous stone called
FLINT-311 LL.



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Fig. 1699.
c/zert, found abundantly near Bakewell, in Derbyshire.
Water, to the depth of 8 inches, is put into the
vat, the broken flints or felspar are added, and the
central shaft being put in motion, the broken pieces
are forcibly rubbed against the runners, as well as
against each other and the paving of the vat. In the
course of some hours the fiints are reduced to powder,
and the mixture has the consistence of thick cream.
Smaller vats of the same construction are used for
grinding the felspar, broken porcelain, 820., used in
the composition of earthenware. This flint-pan was
the invention of the celebrated Brindley, and has been
the means of preserving the work-people from the
'fatal effects of the dry method of grinding fiints
which was previously employed, and which was nearly
as injurious as the grinding of needles and edge-tools.
The stones employed in the construction of flint-pans
require to be very carefully selected, or great loss
may accrue to the manufacturer. Should the stones
contain much carbonate of lime, this would mix
with the flint in grinding, and eventually with the
ware itself, which would thus be rendered fusible
in the kiln, or blister from the escape of carbonic
acid. When the fiints are sufficiently ground in the
flint-pan, the creamy mixture is passed into another
FLINT-PAN.
vat having an upright shaft and arms, by the revolu-
tion of which, and the additionofua further quantity
of water, the finer particlgesuof vflint ar akept sus-
pended, while the larger rand heavieippar‘tfifps sink to
the bottom. The wateficqptaipipgb the finer particles
0 0 , \|\ ?
is drawn off into a resery‘opglwiltrerb \the powder sub}?!
The flint powder gisgfipfifisidered fit to In “8
sides.
with the clay when a wirnifz? )ipt' of ‘it weighsi132
ounces, while an equal a
should weigh 242 ounces.
two principal ingredients being taken, the manufac—
turer is able to mix them in proportions varying
according to the kind of ware to be made, and accord-
ing to his own particular plans, for each manufacturer
usually has his own independent mode of operation.
The prepared clay and flint are united by agitation,
and the fluid mixture is then passed through sieves of
hard spun silk, manufactured expressly for the pur-
pose, and arranged on different levels, as shown in
Fig. 1700, so that the mixture shall pass from coarser
to finer sieves, and be at last reduced to the utmost
1" {Id
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MIXING- ’IKE INGREDILNTS.
.
PM
all

Fig.1700.
uniformity and smoothness, a constant jigging mo-
tion of the sieves being kept up by machinery. The
mixture thus strained and purified is called slip, and
has now to be brought into a doughy consistence for
the use of the potter. For this purpose it is con-
veyed to the slip-house, and boiled in the slip-kiln.
The English slip-house is a long low detached build-
ing, with the tiles placed half-way apart to allow of
the more ready escape of steam. The slip-kiln, a
portion of which is shown in Fig. 1697, consists of
long brick troughs with flues under them for heating
the mixture to the boiling point. During the early
part of the evaporation it is necessary to keep the
mixture constantly stirred to prevent the heavier flint
from subsiding; if this were not done, one part of
the clay would contain too little, and another part too
much flint. There is also a tendency in the flint and
clay, when water is present, to form a sort of mortar,
which speedily hardens, but this is prevented by
diligent stirring. The slip remains in the kiln about
24: hours, and towards the close of this time bubbles
of steam cease to he formed on the surface, and the
mass, when out into, appears to be of a uniform
texture, and sufficiently hard. The abundance of
‘w .
reggae dangled‘; * ,,
The‘densities o
454:
POTTERY AND PORCELAIN.
fuel in England has led to the wasteful and un-
scientific application of it in many of our manufac-
tories, and the slip-kiln is one out of numerous
examples. In countries where fuel is scarce, the
slip is deprived of its superfluous water by other
means. In the potteries of Restrand near Stock—
holm the slip is placed in large square boxes, and
exposed to the air with a southern aspect, by
which means a large quantity of water is got rid of
by the natural process of evaporation. The boxes
are furnished with covers, which are lowered in rainy
weather. When a certain quantity of water has been
‘got rid of in this way, the paste is put into the
hollow cavities of thick plaster moulds, which absorb
sufficient water to bring the paste to the proper con-
sistency for working. It is necessary to keep the
slip in a state of agitation in the moulds, or the result-
ing paste will be denser where it comes in contact
with the plaster than in the other parts. This plan
can only be practised on a small scale; but we are
now about to notice two methods, both of which
deserve the serious attention of manufacturers. The
first consists in enclosing the slip in sacks of strong
and closely woven texture, and then subjecting it to
a considerable pressure, which may be economically
supplied by means of a long lever loaded at the end
of the long arm, and a number of sacks being placed
between two boards near the end of the shorter arm,
the pressure is thus maintained as long as it is
required. A press of this kind will prepare for use
about 1,300 lb. of porcelain paste in 3 hours. A
screw press worked and attended by 2 men, will pre—
pare a ‘day ‘(if 12 hours from 1,350 to 1,575 lbs. of
percelain paste. F _ _ _
It will be seen that this method is a species of
filtration accelerated by mechanical pressure. A more
refined and successful plan is to filter with the aid of
atmospheric pressure, for which purpose the filter is
placed above the vessels AA, Fig. 1701, from which
the air can be removed by connecting them at bottom
with a tube about 36 feet long, terminating at its
lower extremity in a reservoir of water c. If one of
these vessels be full ‘of water, and be made to commu-
nicate with the reservoir by means of the long pipe, a
vertical column of water from 110 to 50 feet in height
will thus be formed; but as the atmospheric pressure
is only equivalent to a column of about 34'. feet high,
[see A111,] it is evident that the upper part of the
column will sink down to that height, or in other
words, the vessel A. will discharge its contents into the
reservoir 0 by means of the pipe, and thus form a
vacuum above. The slip is contained in the filtering
vessels, FF, above, in the centre of each of which is
an opening communicating by pipes with the vessels
an. This opening is covered with an iron grating g,
and a bed of pebbles, 10, is made to cover the rest of
the conical ‘part of the filter. The grating and the
pebbles are covered with a cloth of thick spongy felt,
pervious to water but not to the solid particles of the
slip, firmly secured at the edge of the filter, and above
this is another cloth of hemp for receiving the slip.
On opening the stop-cocks c a, so as to connect one of

the filtering vessels with one of the vacuum vessels, the
atmospheric pressure not being counterbalancedbelow,




Fig. 1701.
exerts its whole action on the surface of the slip, and
forces the water through the filtering cloth into the
vacuum.‘ In the course of 410 to 45 minutes a layer
of slip about 6 inches deep, containing rather more
than 50 per cent. of water, is reduced in depth to
about 21% inches, and is converted into a paste of re-
markable plasticity and containing only one-fifth of
water. This apparatus is better adapted to the pre~

“
‘\“X





“Wei;


\\\\ \\
paration of porcelain than of pottery paste. For the
latter the form of apparatus shown in Fig. 1702 may
be used. In’ this the vacuum is produced by injecting
steam into cylinders c, placed below the filtering bed.
The vessel containing the filter is of cast—iron; the
filtering cloth is shown at 0, resting on its bed of
pebbles P: g is the grating as before.
In the English process, when the slip has been re-
duced to the proper texture in the kiln, it is removed
to another part of the slip-house, where the process
of wedgz'rzg goes on. This consists in cutting up the
mass from the slip-kiln into wedges by means of a
spade, and dashing them against each other to get rid
of vesicles and air-bubbles, which would otherwise
form blisters in the ware. This wedging should be
carried on at intervals during several months, to secure
a fine grain and freedom from flaws. In China, we
are told, a store of clay is prepared 14. or 20 years in
advance, and sometimes a potter will prepare sufii—
POTTERY AND PORCELAIN.
455
cient porcelain clay for the use of his son during his
lifetime. Modern customs scarcely allow of such ar-
rangements, but every manufacturer knows the
superior value of clay that has been kept a con-
siderable time, and the mischief which often ensues
from the use of clay warm from the slip-kiln, or
which has been lying only for a few days. During
this ageing of the paste a true fermentation goes on.
Carbonic acid gas and sulphuretted hydrogen are
disengaged, and the mass in the course of time im-
proves both in texture and in colour. It is probable
that certain carbonaceous and organic matters in the
clay or in the water with which it was blunged, are
the cause of this fermentation. At any rate, they
are thus got rid of, whence the improvement in the
colour of the clay; and the gas in struggling to escape,
produces a kind of natural wedging and slapping,
thus excluding particles of air, and reducing the clay
to a homogeneous mass. The process of slapping
somewhat resembles that of wedging. The workman
takes a mass of the paste, weighing 60 or 701b,
and dashes it down upon a bench before him. He
then divides it repeatedly, by drawing through it a
wire furnished with a handle at each extremity; and
on each division he takes up one portion of the clay
and dashes it down with great force on the other
portion. Care is taken to preserve the grain of the
paste; that is, the layers are slapped parallel to each
other, and not at right angles or obliquely, otherwise
the ware would be liable to fall to pieces in the baking.
SECTION VI.—Tnnow1Ne, TURNING, PnnssrNe, AND
CASTING.
The clay, being thus brought to the requisite state,
is next shaped into articles in earthenware by one of
three processes, named t/n'owing, pressing, and casting.
Of these, throwing is the most ancient, as well as the
most interesting, on account of the skill required in
the workman. It is performed at the potter’s wheel
or lathe, which consists of an upright shaft about the
height of a common table, on the top of which is fixed
a disk of wood of sufficient diameter to support the
largest vessel that is made. The lower end of the
shaft is pointed, and runs in a conical step, and the
upper part in a socket, a little below the circular
board. The shaft has a pulley fixed upon it, with
grooves for 3 degrees of speed, over which an endless
band passes from the fly-wheel, by the revolution of
which any degree of speed may be given to the shaft,
and its top-board. When this wheel is small, it is
placed alongside, and driven by a treadle and crank ;
when large, it is turned by an assistant, as shown in
Fig. 1703.
The mass of dough, as received from the slapper, is
cut up into portions with a brass wire, each portion
being weighed, slapped with the hand, and rolled
up in a ball. A female assistant, called a batter, often
performs this. The thrower, seated with one foot on
each side of the wheel-head, with his elbows supported
on his knees when his hands require to be kept
steady, takes one of these balls, dashes it down upon
the centre of the revolving-board, and with both

hands kept wet by occasional dipping in water,‘ he
squeezes up the clay into a high conical lump, and
again forces it down into a mass to get rid of any
remaining air-bubbles.‘ With one hand or finger and
thumb in the mass, he then gives the first rude form
to the vessel, and with a piece of horn, shell, or por-
celain, called a rib, which has the profile of the shape
of the vessel, he smooths the inner surface, gives it

the proper shape, and removes the inequalities left by
the fingers. In the meantime the assistant keeps the
wheel moving at varying degrees of velocity accord-
ing to the requirements of the thrower. In order to
make a number of vessels of exactly the same size, he
does not entirely rely upon his eye, but employs a
simple kind of gauge, consisting of a peg, or stick,
placed opposite to him, at a certain distance from the
centre of the vessel, whereby he is able to judge of
the required height and diameter of the vessel which
is being formed. The thrower’s work is simply to
produce circular vessels, such as tea-cups, basins,
&c., without handles or ornaments, these being added
afterwards.
We may further illustrate the thrower’s art, by
Fig. 1705, which we sketched at Doulton & Co.’s
Lambeth potteries. The clay used in this coarse
stone-ware is obtained from Poole, Teignmouth, &c.
It is placed in large lumps round the kilns to dry.
It is next mixed in cer- I-l
tain proportions, crush- ‘
ed under edge wheels,
and mixed much in the
same manner as mortar
is. It is well assimilated
by being passed through
a pug-mill in which the
arms and spikes are
arranged on the central
axis, somewhat after the
manner shown in Fig.
17041. The clay is then
weighed up into balls of
the size of the intended







/_lo
5L
/
i I.
Ch»
””JIWIIIW”MIM
" N ‘ (.4.
§ 72‘ "Milli/11!!!!”
article, which in the case ‘ I /
- r i 1 - i ,
now to be notlced Was a . . \\\ \ ,\ \\ \ \ s,‘ \\\ \\m
3-gallon bottle. The rough
ball N0, 1, being dashed Fig. 1704.
456
POTTERY AND PORCELAIN.‘
down upon the board, the attendant sets it revolving
by turning the winch as shown in Fig. 1706. The
man then with hands made very wet with water, raises
up the ball into the conical mass, No. 2, for the pur-
pose of squeezing out the air, and rendering the mass as
homogeneous as possible, effects which are produced
in the paste for the finer kind of pottery ware by
ageing, wedging, and slapping, as already noticed. The
man next presses down the conical mass so as to form
the dumpy figure No. 8, in which he carefully forms
the bottom of the vessel by his fingers and also by
means of a rib. The next operation, called imucklz'rzg-

Fig. 1705. SUCCESSIVE s'rnes is THE 'rrmowrxc or A sroxn-
'WARE BOTTLE.
up, is performed by placing one hand in the vessel No.
3 and the other on the outside, and pressing the clay
between the knuckles of the two hands, at the same
time raising the arms, the thick sides of No.3 are
thinned out into No. 4', the board or wheel of course
being kept revolving all the time at various rates of
speed as experience suggests. The next process is to
make the sides truly ‘cylindrical, which is done by
the hand inside and a flat rib outside opposed to each
other. A flat surface somewhat corresponding to the
rib is formed by the hand inside by stretching out
the index finger straight against the thumb as shown
in the figure. The wide parts ‘of No. 5 being care’
fully finished, the neck is gradually contracted and
the top finished as in No. 6. The bottle is then cut
05 by passing a wire between it and the board, but
before removing it from the board a list stopple is
put into the mouth for the purpose of confining the
air. If it were not for this simple but not very
obvious precaution the large heavy mass of soft hollow
clay would collapse in being removed, but by stopping
the mouth the enclosed air acts as 'a sort of cushion
or elastic support to the 'mass. When the bottle has
become sulficiently consolidated by drying it under-
goes the operation of turning (see Fig. 1706,) as will
presently be noticed, the handle is glued on by means
of slip, and it is ready for firing.
In large potteries, where a number of potters’
wheels or lathes are in use, they are turned by means

of the steam-engine of the establishment. In order
to vary the speed the band for each wheel is passed
over two cones, and the band is under the control of

the thrower’s foot by means of a forked lever, so that
he can shift it at pleasure to a wide or to a narrow
part of the cone.
As soon as one vessel is formed, and out off at the
base with a fine brass wire, the baller supplies another
ball of clay, and the new-made vessel, (now said to
be in its green stale) which he lifts off the wheel, is
placed on a board, and when a sufficient number are
collected, he carries the whole into the open air, or
into a warm room, where they part with their moisture
sufliciently to allow of the next process which is
turning. -
The turning of earthenware in the Staffordshire
potteries, does not differ from that of wood, ivory,
or metal, and it is a curious sight to watch. a rude
clay cup or bowl spinning round in the turner’s
lathe, with long and broad shavings flying off from
it, under the operation of the cutting tools. That
the turner may stand quite steady at his work, mo-
tion is given to the lathe by an assistant treadcr.
This is usually a female; and while employing her
right foot at the treadle, she also attends to the green
vessels on the board, moistening their upper edges,
and clearing away whatever interferes with the turn-
ing. A clay ring, scarcely moist, is kept on the chuck,
the vessel is put on it with the upper edge (already
moistened) turned downwards, and pressed into the
clay ring. The ‘surplus clay, left by the thrower, is
then rapidly removed by the tool, and the vessel
brought to the required thickness. When this has
been completed, and any desired fanciful indentations
and cuttings have been made, then a retrograde motion
is given to the spindle, during which the upper sur-
face of the vessel is smoothed and solidified by the
pressure of a broad tool, and the vessel is then cut
loose, and delivered ‘to the handler, or it is dried for
the biscuit oven. Clay for handles, spouts, &c. is
first formed into pipes at a small press, which forces
the clay through a metal tube of the required size and
form. The clay‘ pipes, thus formed, are cut up into
lengths, and shaped with the hand. They are attached
to the articles by means of slip, which unites them
quickly and perfectly. Superfluous clay is scraped off
with a knife, and the vessel cleaned with a damp
POTTERY AND PORCELAIN.
457
sponge, to‘ give it a uniform appearance. Plaster-of-
Paris, or steel moulds, are used where figures and
foliage are required, and are attached as before. In
some cases flowers and leaves'are formed by hand, with
considerable dexterity and attention to botanical cha—
racter. The Editor has witnessed the skillexhibited
in this respect by the artists ‘employed in the cele-
brated porcelain works at Meissen, near Dresden,
where a botanist of talent is employed to superintend
the operations. .
When articles have to be executed on a large scale,
the method is the same in principle as that just alluded
to of forming ornaments in moulds, and is called
pressing. Plaster moulds of every variety of size. and
pattern are employed in great numbers, for all plates
and dishes are thus manufactured, and a complete
set of patterns is required for every new pattern, and
for every size of the same pattern. Moulds for plates
and other shallow articles consist of only one piece,
and are formed by taking the impression of the in-
side of the article, or the upper surface of the model
in plaster. Plates, dishes, saucers, cups, and hand
basins are now made by the process of flat-ware
pressing, an operation which is conducted as fol-
lows :—a plate being ‘taken as an example. The
plate-maker stands at a bench before a whirling tat/ts
similar to ‘the thrower’s, but moved by a horizontal
pulley or jigger turned by a boy. On his left hand
is a batting block of wet plaster and a mass of well
beaten clay. Near him is the stove-room in which
moulds are ranged on shelves to, dry. The plate-
maker first cuts his clay into lengths with a wire, and
tears oif a piece which he batts out thin upon his
block by a stroke or two of his batter, which is a
plaster mallet, and he polishes the surface of the
batted clay by pressing the side of a smooth knife
against it. The boy then places a mould on the
whirler, and stations himself at the handle of the
jigger: the man places the clay on the mould, which
is then set whirling, and he presses it down close
with his hand. A profile or earthenware tool, which
gives the form to the bottom of the plate, is next
pressed upon it as it revolves. Where great pre-
cision is required, the profile is mounted in a carrier
0, Fig. 1707, which can be adjusted by screws upon


Fig. 1707.
the arm I of the frame FF, and fixed to the proper
height by the screw R. The arm I descends in a
groove g, to the exact depth required for the thick-
ness of the plate. When the proper shape is given
the motion is stopped, and the boy catching up the
mould with the plate upon it runs with it to the hot
room, places it on a shelf to dry, and returns with an

empty mould which has been drying. In the mean
time the man has batted out another piece of clay for
another plate. In about two hours, the plates become
sufficiently dry to be removed from the moulds, but
the moulds themselves having absorbed much moisture
from the plates, are left to dry before they can be
again used. One workman, with the assistance of
two boys, can make from 60 to 70 dozen of ordinary
plates in a day of 10 hours, using the same moulds
about five or six times in the period.
The whirling table having a circular motion, is of
course only adapted to articles with a circular outline.
At the Royal porcelain works at Meissen we saw a
whirling table with an elliptical motion, adapted to
dishes and other articles. For articles of less regular
figure, the whirling table is not moved by a wheel
and strap, but is simply supported at the end of the
vertical rod, and left free to turn on receiving a gentle
impulse from the .amoulder. Where the surface of a
large article has to be covered, the clay is rolled out
upon a moistened sheepskin, the rolling-pin being
supported by two guide rules. The clay is lifted by
means of the skin, placed upon the mould, pressed,
smoothed, and adjusted, and finished with a wet sponge,
and wet leather. The edges are then trimmed, and the
maker’s name or other mark is stamped upon the back.
The above simple form of pressing is not applicable
to deeper vessels, which are made by what is called
hollow-ware pressing or sqneezing. The mould in this
case is made in several parts, accurately fitting together,
as shown in Fig. 1708, which represents a mould for a
h ' ll l -
\ x f v ‘I [I m \ i
, I f/ .’ -_'-_________
l ' .







(s s
it‘











._- - _,___ -. I I I! H4“ ., \W i. in _®
:—:_ W 1 l n.
“my I .llllllwl
Fig. 1708.
foot-pan. The base of the mould has 4'.‘ projections,
which fit into cavities of the two halves for the upright
portion. One of these uprights is shown with the pan
in it in the act of being detached. In moulding such
an article, the clay is well kneaded, batted 'out, and
spread over the bottom, which is placed on a whirler
or flat board mounted on a vertical axis, so as to
turn round easily: the two halves are each lined with
clay, which is well worked into the grooves and made
to project a little at the edges. Each half is then
placed upon the base piece, and secured by passing a
string round the outside of the mould. The joints
are then well worked with the wet finger, and fresh
clay added, and slip applied so as to make the seams
adhere perfectly. The mould is then put aside, and
another filled in like manner. Handles for large ves-
sels are prepared in plaster dies or moulds. For
tags. or solid handles. the clay is well rammed into
4158
POTTERY AND PORCELAIN.
the hollow mould, shown to the left of Fig. 1709,
then inverted and dashed-down upon the mass of clay
shown to the right of Fig. 1709. The mould is then
g’
. 1.9‘-
' " \\
‘iii/172.17’ '
J1‘
.
I a’,
-’
x"




- taken up, leaving
{l'ul h the moulded lug
! .li'g', on the mass, from
_ . till fill“, which it is re-
l'” i-
moved by pass-
ing a wire under
it. For openhan-
dles the moulds
are intwo parts;
these are filled
separately with
clay, and then
put together and
struck, as shown in Fig. 1710, which causes the two
sections of the‘ clay to adhere. On opening the mould,
the handle is taken out entire, and fettled smooth.1
The method of forming pressed wares in Staffordshire
is as follows. The presser first kneads and bats
out a number of pieces of clay. One of the sec—
tions of the mould is placed on the whirler, and
a bat is forced into it .with a moist sponge, and
worked well into every part. All the sections being
thus lined with clay, the edges are trimmed, moist-
ened with slip, and the parts of the mould are care-
fully brought together, and secured by a strap passed
round them. The presser then passes his finger
up every joint, so as to make a groove, into which
a thin roll of clay is inserted, worked in, and
smoothed with moist leather or a cow’s lip. All
marks are removed with a sponge, and the inside is
washed with pure water. The mould and its contents
are set aside for awhile, then again placed on the
whirler, and polished with a flexible plate of horn.
It is then placed in a warm room, and when sufficiently
dry, the article is removed from the mould and fettled,
or trimmed with proper tools, so as to remove all
appearance of seams. The outside is cleaned and
polished with moist sponge, the handles, &c., are
added, and a little more polishing with the horn com-
pletes it. It is then set aside to dry previous to
baking. For original or elaborate designs, the ser-
vices of experienced artists are required to form, in
the first instance, models in clay. At Meissen, the
Editor saw models of a complicated kind for four
vases, emblematical of the ancient elements—fire, air,
earth, and water—the moulds for which consisted



.1
9;},

n
,_..\\~




r f‘f'rl
“filth
‘ v -‘.‘ .
I _. ‘"1;
i.
: t
t ' f
i i if“
1'1
i


Fig. 1710.

F (1) Several of our figures are from sketches made at the
potteries of Messrs. Doulton 8.: Watt, of Lambeth.

of 150 separate pieces. When the articles are of
a simple character, they are formed by a union of
throwing and moulding.
Delicate articles for ornamental purposes are
formed by casting. The clay and flint being mixed
with pure water to a creamy state, are poured into
moulds, the plaster of which quickly absorbs water
from the portion which comes in contact with it,
and hardens it sufficiently to allow of the central
fluid portion being poured 06. A coating of clay is
thus left attached to the mould, and when this
is partially dry, a second layer of clay is poured in,
which serves to give strength and consistence to the
first. The superfluous portions of this second layer
being also poured off, the mould with its contents is
placed in a stove, until sufficiently dry to be sepa-
rated. The cast is then taken out, and carefully ex-
amined and retouched by the modeller. In this way
porcelain statuettes are manufactured. The lace
which sometimes adorns them, and which appears as
if originally formed of porcelain, is actual manufac-
tured lace, dipped into slip, and thus fully imbibing
the porcelain material. 'The heat of the furnace
destroys the thread while it hardens the porcelain
material which takes its place: hence the curious and
beautiful effect.
The processes described in this section belong for
the most part equally well to' pottery or porcelain
paste. We may, however, notice a few special articles
made in one or other of these materials.
A very interesting variety in the porcelain manu-
facture has been invented by our English makers, and
called Parian, Garrard, or stataarg porcelain. It was
introduced six or seven years ago by some enterprising
Staffordshire firms, and it certainly presents a great
similarity of efiect with the beautiful marbles after
which it is named. This effect is attained chiefly by
the employment of a soft felspar in the porcelain
instead of Cornish stone. The agreeable yellowish-
white tint which characterises this material is not
due to any colouring matter mixed up in the com-
pound, but to the small quantity of oxide of iron con-
tained in the clays and the felspar. During the firing,
as the atmosphere of the inside is oxidizing, this small
quantity of iron forms with the silica a silicate of per-
oxide of iron, which gives the colour. These figures,
instead of being pressed in moulds in the regular
way, are cast with the compound prepared in a liquid
state; this causes a diminution of their bulk in the
firing process, amounting to no less than one-fourth.
Consequently much dexterity and a knowledge of the
human figure are required in this manufacture, for
the subjects are cast in a number of separate pieces,
and their subsequent joining and repairing call for
much skill in the artist. “ If we compare our Parian,”
says M. Arnoux, “with the biscuit made on the con-
tinent, we shall perceive the enormous difi’erence in
their relative appearance : while the continental
biscuit acquires in firing a greater sharpness, it is the
reverse in the Parian ; whilst the former, with its
hard, cold appearance, will reject the light, this light
penetrating into the latter to a certain depth, gives it
POTTERY AND PORCELAIN.
4159
a softness which has never been realized before.m In
addition to the beautiful figures in Parian which ap-
peared in the Great Exhibition, there was a novel and
successful adaptation of this substance to the purpose
of a chimney-piece, exhibited by Messrs. Minton.
To the same manufacturer we owe the revival of a
curious, but long-neglected substance, called majolz'ca,
or Majorca ware, from the seat of its early manufac-
ture. In the 16th century this material was manu-
factured in great perfection in Italy under royal
patronage, and beautiful services of it were made,
and decorated with paintings after the best masters.
It was then valued as much as we esteem the finest
porcelain, although, in fact, it was nothing more than
a calcareous clay gently fired, and covered with an
opaque enamel of sand, lead, and tin. But this
enamel afforded an excellent ground for painting, and
the designs of Bafi'aelle gave a name and distinction
to this ware, while a variety of grotesque and quaint
devices were also used to adorn it. Mr. Marryat, in
his “Collections towards a History of Pottery and
Porcelain,” gives an account of this ware, derived
from Passeri’s scarce work. The purposes to which
it was applied, while in vogue, were many and
various. Cisterns, vases, ewers, amatorz'z' (vessels
adorned with the portrait of a favourite lady), nuptial
vases, small plates for ices and sweetmeats, vases for
holding different kinds of wine poured out from one
spout, small flasks in the shape of apples and lemons,
cups covered with tendrils, statues of saints, birds
coloured after nature, painted tiles for walls and
floors, are among the articles mentioned as being
many of them of admirable workmanship. This ma-
jolica, it is thought, revived at the present day, may
be useful for friezes and other architectural orna-
ments, and also for slabs to be painted on, forming
a cheap material in which the colour would sink, and
be equal in brightness to that attained on the enamelled
surface given to copper. The flower-pots and vases
of majolica in the Exhibition gained much praise.
Another manufacture, which has been greatly
fostered by the revived taste for decoration of the
present day, is that of mosaic, plain, and eacaastz'c
tiles. The processes of the manufacture, as we ex-
amined them a few years ago, at the works of the
Messrs. Minton, of Stoke-upon-Trent, are as follows :—
Encaustic tiles consist of a body of red clay, faced
with a finer clay, which bears the ornamental pattern,
and strengthened at the base with a thin layer of a
clay different from the body, which prevents warping.
The red clay or marl, forming the body of the tile,
is obtained from Gobshurst, about four miles from
Stoke-upon-Trent. It is dug out and left to undergo
weathering or wintering, namely, exposure to the air
for upwards of half a year. A portion of this clay,
when brought into the factory, is thrown into a tank
with water, and- worked about with a blunger. When
partially divided it is laded into another tank, and
regularly blunged; this operation is again repeated,

(1) Lecture on the Ceramic Manufactures, 850. of the Great
Exhibition, read June 2, 1852, by L. Amoux, Esq., before the
Society of Arts. . '

and the clay is passed through sieves of varying fine-
ness, and, with a certain admixture of other composi—
tions, is afterwards either dried into hard lumps and
ground, or evaporated at the slip-kiln, according to
the method which is to be employed in its subsequent
treatment.
In the manufacture of what are called (Zry/ tiles,
according to the method patented by Mr. Prosser,
the powder, as it comes from the mill, is placed
on slabs of plaster-of-Paris, slightly damped. It is
then sifted through fine sieves, and subjected to
intense pressure, by which the particles of powder
unite into firm solid slabs or tiles. This is effected in
the following manner. At the lower extremity of the
screw of the press is fixed a steel plate, of the size
and pattern of the intended tile: this fits into the
upper part of a steel box of the same dimensions, the
bottom surface of the box being ribbed, that the tile,
receiving a ribbed impression on its under surface,
may adhere more strongly to the mortar or cement
by which it is imbedded in the wall or pavement. A
portion of the powder being swept into the metal box,
the steel plate is forced down upon it, with a pressure
which may amount to 400 tons. A thickness of 3
inches of powder is thus compressed-into a tile 1 inch
thick, with sharp edges, and a beautiful polished sur-
face. Tiles, scale-plates, table-tops, furniture panels,
and other articles of considerable size, are thus pro-
duced, also, with smaller presses, t'esserae for mosaic
work, and ornamental buttons for shirt studs. These
articles are taken from the press to a hot room, for a
week or two, where they are ornamented, glazed, and
fired. It appears that new improvements have been
made in this manufacture since the Exhibition closed.
Steam power is now employed, so that the pressure
on each tile is mathematically the same, and those
slight variations, inevitable in work regulated by
hand, are now avoided. “Each machine can make
5,000 tiles in 2114 hours, and as soon as applied to the
tesserae the number will not be less than 115,000‘in
the same time. Only one man is required, viz. to
take the tiles as they come out finished from these
machines.”
Encaustic tiles are made from the clay after it has
been evaporated in the slip-kiln. It is wedged and
slapped in the usual manner, and ‘then slapped into
a block, of the form of a cube, or parallelopiped, and
placed before the tile-maker, who cuts 0d a square
slab by passing a wire through it: upon this, the
facing of finer clay, coloured to the desired tint, is
batted out and slapped down; it is then turned over,
and a facing is applied to the bottom of the tile to
prevent warping. The tile, thus formed, is next
covered with a piece of felt, and put into a box
press: a plaster-of-Paris slab, containing the pattern
in relief, is then brought down upon the face of the
tile, and impresses in the soft tinted clay the design
which is afterwards to be filled up with clay of another
colour. The maker’s name is then stamped on the
back, and a few holes to make the mortar adhere.
The pattern now remains deeply indented in the face
of the tile, as shown in Fig. 1711, and over this is
I460
.ro'rrnnr AND PORCELAIN‘.
poured a quantity of»: slip or- clay in a semi-fluid state,
' _\ _ 2;.
and generally of some
rich or deep colour.
This‘i‘completely covers
the‘ surface, and hides
tliepattern,which is to
j‘ ‘be revealed by an after
process. .-, In as hours
the slip becomes toler-
ably ‘hard :- the‘ tile is
then placed on a small
. whirler, and the pat—
~= " ternandtheground are
brought out by scrap-
:lug away the superfluous clay, Fig. 1712, and leaving
- it only in the depres-
sion caused by the
pattern mould. The
whole is finished with
_ .l_~_-~.a knife, and defects
' corrected: the edges
‘ are squared, and their
\ ills/*1 sharpness rounded off
__,__,-" with sandpaper’. The
— ' tiles are kept for a
- week in a warm room
called the green-house, whence they are subsequently
conveyed to a izot-izouse, where strong heat completes
‘the drying. They are then arranged in seggars, and





"~44; "8-—
Fig. 1712.
i t ;fired as in baking pottery and porcelain, only about
double the time is required. The oven is left to cool
for six days, and the tiles are then drawn in their
finished state. These tiles contract in firing to the
‘extent of %th or Tlgth in every inch. The dry tiles
‘contract about from TIG-th to 516th. The above process
,is nearly the same as that employed in the middle
ages, in making pavements for churches both in
France and England, and 2also for the beautiful pot-
tery called Henry II.’s ware, prevalent in the 16th
century. These processes are being largely adopted
.in Prussia. In the architectural court of the Great
.Exhibition were specimens of tiles manufactured on
the dry method by Mr. Minton, in imitation of term-
cotz‘a stone. The ‘introduction of such ornamental
works instead of carved stone, is a great point as it
respects economy. The manufacture of terracotta,
or baked clay resembling stone, is likely to become
an important branch of industry in England, if the
material can be made to resist the climate, and brave
the effects of frost. The clay requires to be fired to
‘the point at which the cohesion of the particles ex-
ceeds the expansive power of water when frozen.
When the clay used cannot itself be made to acquire
;that power, some calcareous clay, or some vitreous
,rnaterial is added, in due proportion. In Vienna some
of the finest buildings'are wholly ornamented in terra-
cotta, and there is no doubt of its adoption here, if it
should be found sufiiciently durable.
Snc'rron VII.—--FI]3.ING.
r The vessels and other articles produced by throw-
ing, pressing, and other processes, described in the

last ‘section, are raised to a very high temperature,
' whereby they‘r lose their friability, and acquire solidity
and density. Some of the admired wares of different
nations have not been fired, but simply baked by ex-
posure to the sun. Such are the bricks of many parts
of Asia and Africa, Etruscan vases, and similar articles
intended to decorate houses or to form part of the
furniture of tombs.
.The temperature at which ceramic wares are fired
has a great influence ‘on their character and texture.
The usual effect of firing is to convert the article into
a hard sonorousjbz'scm'zf, more or less porous, and re-
quiring the application of glaze and a second firing
in order to remove the porosity and give a durable
smooth surface not very liable to tarnish. In the
case of porcelain, the temperature of the first firing is
sutficient for incipient vitrification, so that, as far as
use is concerned, the article is complete at one firing;
the second firing being for the purpose of fixing
enamel ornaments, &c. The firing of ceramic wares is
a costly process, on account of the great expenditure
of time and fuel. It was, therefore, a great improve-
ment when Wedgwood introduced a ware so com-
pounded that partial vitrification took place at the
first firing, thus rendering a second unnecessary. The
Lambeth potters, also, by the ingenious artifice already
noticed (SEO. II.) of throwing salt into the kiln at a
certain stage of the firing, manage to fire and glaze
certain coarse wares at one process.
The arrangement of the kiln for firing ceramic
wares varies with the nature of the wares themselves
and the kind of fuel employed. Fig. 1713 represents
a section of the pottery kiln. It is a massive cylinder



Fig. ms.
of brickwork 20,20, bound with iron bands, and sur—
mounted by a dome, with apertures [Z 72. in the top to
allow of the exit of smoke. These apertures are im-
mediately under the chimney of an outer hovel H,
_ which protects the kiln from the cooling effect of air
and rain, and also assists in carrying off the smoke.
The kiln is heated ‘by 6 or 8 fire-places placed
POTTERY AND PORCELAIN. f
M31‘-
equidistantly round the cylinder. One of them is.
shown in the section. f is the fire, g the grate, a the
ash-pit, (Z the fire-door: the draught is regulated by
enlarging or contracting the openings 0 and it’. Be-
tween the wall 20 and the chimney c is a space r, about
15 inches wide, and 8% feet above the floor of the
kiln: below this floor are flues f t for the circulation
of the flame: these flues all meet in the centre a‘ : at
as are vertical fines, and at s n are sight holes to
allow the men to watch the behaviour of the fire, and
regulate the draught of the fines c c.
The porcelain furnace at Sevres, in which wood is
the fuel, is a sort of triple kiln KK’ K", Fig. 17141. A

up
. “ d
‘z
3""-
'. j. Exp‘ l
<__ i. 39:‘
\\ 1
.y ‘
l I ‘
'1 . , )
lull!‘ iiymmmm
u‘; '
l
____.--
i1. '
he i _ p733“. .
i , tilt“? ..
e
ll
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.llll
\l
.;‘.'.' ' ii ‘ v ’
1w‘ ‘ ._ '\ -- I i \
.~\\\ - \w' _ \ .\>\}\\' \ ‘ k
Fig. 1714.


very elevated temperature is obtained in xx’, sufli-
sicnt for baking the porcelain: the temperature in K”
suffices for the glazing and enamel colours. Each of
the first two kilns is heated by {t exterior fires ff;
with downward draughts. Each fire is contained in
a rectangular fire-place f, with a grate g, and an ash-
pit below, which, together with the stoke-hole a,
admit of being closed from the outside. The flame
enters the kiln by a number of square openings 0 0 in
the wall. When the porcelain is arranged in the
kiln a quantity of small live coal is put upon the
grates, and on this small cleft wood. The fire and
ash-pit door being closed, the kilns act the part of
a chimney and begin to draw. The air enters by the
opening above f, and the flame thus made to descend
enters the kilns by the openings 0, and the flame and
current of hot air pass from the lower to the upper
kilns through the apertures it in the vaulted roofs, the

products of combustion escapingat the narrow part-
of the cone ct, where a damper is placed for further
regulating the draught. The wood burnt is aspen
and birch: coal gives too fierce a heat, and too smoky
a flame, which imparts a yellow tint to the porcelain,
and greatly deteriorates its value. The kiln is con-
structed of fire-brick, bound with iron hoops on the
outside. Each kiln is furnished with a door D, which
is used in charging, and is bricked up before the.
firing; but a number of smalhopenings ss are left,
which serve as sight-holes.
Porcelain and the better kinds of pottery are not
exposed to the direct action of the fire, but are pro-
tected from the smoke and the injurious products of
combustion by being packed, when sufiiciently dry for
the kiln, in coarse strong open vessels, made of Staf-
fordshire marl, and called seggars.
of pottery are, however, differently arranged. A num-
ber of slabs of fire-clay are set up on edge, as shown
in Fig. 1715, and upon these similar slabs are placed
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Fig. 1715.
horizontally, thus leaving a multitude of spaces in
' which the articles to be baked are placed during the
building up of this arrangement. The flame and hot air
being directed along approprate flues, penetrate all
these cells and raise the articles to the required tem-
perature. It is in such a kiln as this that articles
glazed by means of salt are fired.
The seggars or cases in which porcelain and the
finer kinds of pottery are placed, are made of a mix2
ture of fire-clay and old ground seggars. They are
of various shapes and sizes, according to the kind of
articles which they have to contain. They are made
by well kneading the material, rolling it out, and
moulding it upon a box or shape of wood. They are
first set to dry on shelves arranged round the interior
of the hovel or hood 11, Fig. 1713, and they are baked
in the inner space r r of the same kiln. If the segé
gars are carefully prepared and of good materials,
they admit of being employed many times in the
kiln. Considerable skill is required in packing the
articles in the seggars, so as to economise space and
afford them the full benefit of the fire. If the articles
to be baked are not likely to soften or vitrify under
The coarser kinds‘
462
POTTERY AND PORCELAIN.
the action of the fire, or if the glaze is not yet put
on, they may be placed in the seggars in contact, so
as mutually to support each other, care of course
being taken that the lower pieces be not distorted
by the weight of the upper ones. In this way the
pieces may be made to support each other and pre-
vent distortion. Pieces of large form or complicated
shape may even require supports to prevent them
from warping. The supports are of fire-clay, and exactly
fit the parts supported; or
$ if the article he very thin,
° it may require support, as
in Fig. 1716,“ to prevent
warping. For some kinds
of porcelain a quantity? of
Fig. 1716. sand or powdered flint is
interposed between the pieces. Saucers are kept in
form by an earthenware ring, called a saucer setter
rz'ug .- cups- have also a ring of earthenware on the
top of each to prevent their touching. Figs. 1717,
1718, show the method of packing vessels of similar
form in the seggars.
ss, Fig. 1717, shows
the section of the
seggars, and 0 a a
ring of clay to make
them tight; pp are
projections for sup-
porting a vessel of
fire-clay, ss, in which
the bowl, also shown




i Fig- 171?.
in section, securely stands. Cups are also sometimes
arranged as in Fig. 1718, in which the projection pp
serves to support a ring
0 for supporting the
\M 8\i edge of the cup, while
‘er 1% the handle it passes
wwgmmj. _ through a space cutout
m of the ring, and the
we“ base 6 occupies the in-
.°'\\\\ W a


_ ternal cavity of the
"m . ring. The seggars,
h “u when filled, are con-
mmijl, ‘j 1 veyed to the furnace
, \l and piled up, so that
k the flat bottom of one
‘ Fry-1718- seggar becomes the
cover to the one beneath it ; but to prevent the
entrance of smoke, a ring of soft clay is placed on the
upper rim of each. Care is also taken so to arrange
the seggars that the largest and coarsest articles shall
receive the greatest amount of heat. About 30,000
pieces of ware are.- included in one baking. Fig.
1719 represents a porcelain kiln in the act of being
filled, and Fig. 17 20-the arrangement of the seggars,
some of them in section for the purpose of showing
the enclosed pieces. The flame enters the kiln by
the openings ff; and is prevented from playing directly
upon the seggars by a screen or guard of fire-clay
p j). The buugs or piles of seggars is B, are steadied ~
by means of short struts. B shows the method of
arranging a large porcelain slab for firing.

The kiln, when filled, is bricked up at the door, the
fires are lighted, and for from 33 to 410 hours the
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baking goes on under the watchful care of experienced
men. The fire is usually lighted in the evening, kept
up with considerable force all night, the flames issuing
'7 7f‘. all‘ r 511'"
‘>__.' ll, * '
.
,‘_—__~--— 1: ., .._..~ - ’~
:1, 1. ~11», 1
.
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it
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if‘
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Fig. 1720.
from the chimney, and early in the morning the first
mate/r is taken out to see how the baking goes on.
These watches, or trial-pieces, are rings, shown in
Fig. 17 21, made of fire-clay, which changes colour
with the temperature. A number of them are so
placed in the kiln that the fireman can insert a
long iron rod and draw out one of the rings at plea—
sure, and by the appearance of this he is able to judge
of the heat of the kiln, and increase or lower it as he
thinks needful. When the trial-pieces convince him
that the baking has continued long enough, the fire
is ‘allowed to go out, and the contents of the kiln are
left to cool gradually for 24 hours or upwards.
The quantity of coals consumed in one baking is
about 14 tons. .
With respect to the whole process of firing, and to
this large consumption of coal, M. Arnoux throws
out a valuable suggestion, and thinks he can foresee

\\\\
POTTERY AND PORCELAIN.
4:63
the time when the ware will be fired with gas, with a
precision and case which cannot be afforded by the
present system. “ In our present method,” he re~
marks, “ I do not think we use more than two-thirds
of the heat which might be given by the fuel, whether
owing to the insufficiency of draught, to the heat
appropriated by a large number of exterior feeders,
or because at the end of the firing these months are
full of coal which has not produced all its useful
effect. It would seem easy to accomplish the same
firing by combustible gases prepared in or out of the
factory, and applying all their heat in the inside of
the oven. You could understand my idea by sup-
posing established on the coal-mines an apparatus
which will at once effect the distillation of the coal,
and the conversion of the coke into oxide of carbon.
The result would be a gaseous mixture highly com-
bustible, which could be supplied to the factories by
means of large pipes. The manufacturer would have
only to mix these gases with the quantity of air he
would require, according to the nature of the pottery
to be fired. In the present state of science, I do not
think it altogether utopian to hope that we may be
enabled to purchase, from a common reservoir, the
heat or the electricity that we shall want for our
domestic or manufacturing purposes, just in the same
way as we are now purchasing our light.”
Sncrrorv VIII.——GLAZING AND PRINTING.
The ware as it comes from the kiln is called
bz'scaz'l, not because it has been z‘wlcc coolcccl or baked,
as the name implies, but from its resemblance to well-
baked ship-bread. Wine-coolers and other porous
'vessels are finished in this state, but the great pro~
portion of articles, after careful examination, have to
be finished by simple glazing, or they have to be
printed, painted, or ornamented in some way, previous
to the glazing. In either case the glaze consists of
the ingredients of some kind of glass fritted or melted
together in a furnace, and when cold, reduced to
powder. This powder being stirred up in water, the
articles in biscuit are dipped into it, the effect of
which is to cover their surface with an equable layer
of the powder, and on passing them through the glaze
or gloss-coca, the powder melts into a glass, which
forms the ordinary surface of pottery ware. The
patterns and coloured figures are put on while the
ware is in the biscuit state. The addition of the
glaze, which is a white opaque powder, entirely con-
ceals the patterns, 850., but the effect of the second
firing being to convert this powder into a transparent
glass, the pattern is seen through the glaze.
But as every kind of ware is not ornamented with
a coloured pattern, and as all glazes are not transpa—
rent, it is desirable first to inquire a little more
minutely into the composition and nature of glazes.
The pottery of certain rude nations, (that of Peru
for example,) is rendered impermeable by water, by
rubbing it while hot with tallow, which being partly
charred, fills up the pores, and gives the ware a black
colour. Even the refined Etruscan and Greek vases
are covered with a black carbonaceous non-vitreous

varnish, which wears off in the‘ handling: this may
probably have been produced by a similar process.
Wine and oil jars are rendered water-tight in Spain
and Italy by rubbing them with wax: an ancient
practice still followed.
M. Brongniart distinguishes three kinds of glazes,
viz. cca'zzz's, c'maz'l, and coaverlc, for which we have no
equivalent terms 3 for although we may translate the
first into carats/z, the second into enamel, and the
third into cover, yet our potters only recognise the
single term glaze. The ornamentation of porcelain
is more akin to enamel-painting than to glazing, and
as such we shall notice it hereafter.
The first glaze or ccrm's, refers to those common
transparent lead glasses, which fuse at a much lower
temperature than is used in baking the ware: such
are the glazes for the various kinds of pottery; In
the c'maz'l or enamel, tin takes the place of lead ;‘it is
opaque, and is used for majolica and other kinds of
fine pottery. The coaccrlc is a glass With an earthy
base, and fuses at a temperature equal to that at
which the ware is fired. This kind of glaze is used- for
hard porcelain, and certain descriptions of pottery.
The object of these glazes is to render the ware
impermeable to liquids; to give it an agreeable du-
rable lustre, and to preserve the colours and patterns
which have been imparted to it. The glaze should
not have too strong an affinity for the paste, or in
the second firing it will sink into it, and combine so
completely with it, as to disappear from the surface.
The glaze must adhere so firmly to the ware, and
expand and contract with it in the sameproportion,
as not to be liable to craze, crack, or scale, on being
exposed to sudden changes of temperature. This
crazing of the glaze is a great evil, for the cracks by
their capillary attraction absorb fluids which come'in
contact with them, and if these fluids are of an olea-
ginous or fatty nature, they cannot be got rid- of by
ordinary washing, and soon give an ill odour, and a
black appearance to the ware, and greatly promote
the scaling off of the glaze. There are also fatal
objections to lead glazes: they not only injure the
health of the persons engaged in the glazing depart-
ment of the pottery, but the persons using the
ware are liable to be seriously affected by this
poisonous metal, which is readily dissolved out of the
glaze by means of vinegar and acid substances, which
are of common use as articles of food.
The ingredients of glazes are very various. The
felspars and certain volcanic scoriae are used where
the point of fusion is required to be high. A second
class of non-metallic glazes includes common salt,
potash, boracic acid, phosphate of lime, and sulphate
of baryta. A third class of glazes consists of earthy
and metallic substances simply mixed together, or
fritted into a glass. These are silica, and lead, or the
enamels of silica, tin, and lead. A fourth class
includes pure metallic oxides, or sulphurets ; such as
oxide of lead in the form of litharge or minium,
oxide of manganese, oxide of copper, &c. The sub-
stances in the third and fourth classes, if not pre-
viously fritted, form a glass at' the expense of the
41641
POTTERY AND PORCELAIN.
silica of the paste which they are intended to cover;
but such glass is usually soft, and yields readily to
the action of acid and fatty substances.
Gla-zes are also distinguished as transparent, opaque,
and coloured, according to the kind of ware to which
they are applied. If the paste is of a pure white, or
even coloured, provided the colour be agreeable, a
transparent glaze will exalt its beauty; but if ‘the
paste is not of a good colour, an agreeable effect
may be imparted by means of opaque glazes, or even,
previous to the firing, by dipping the article, in the
green state, immediately after it has been turned,
into a slip made of a superior kind of clay, a species
of veneeriug which has been practised with much
success. By this process, an article thrown with a
clay of a disagreeable red colour, but with otherwise
xcellent properties, may be afterwards veneered on
the inside with a beautiful white paste, and on the
outside with a paste coloured according to the taste
of the artist. Such an article may then be finished
with a transparent glaze. Transparent glazes are, as
already stated, true glasses. Opacity is given by
means of oxide of tin, and probably also in some
cases by phosphate of lime. Colour is produced in
glazes by the oxides of manganese, of copper, and of
iron: or, by the introduction of these oxides, together
with those of cobalt and of chromium, into vitreous,
opaque, or semi-transparent glazes.
As the number of pieces to be glazed at one time
is usually very considerable, the glaze must be applied
by some effectual but expeditious method. For this
purpose, the glaze, reduced to fine powder, is mixed up
with water, with the addition of some vinegar, which
is said-to prevent the too rapid subsidence of the
‘powder, and the piece of biscuit ware is plunged
below the surface‘; the porous article rapidly absorbs
the water, and in doing so drags in as it were, and
attaches to itself, that portion of the powder which
was suspended in the water absorbed. If this simple
operation be performed with address, and only the
proper time allowed for immersion, the biscuit will
be equally and properly coated with the glaze powder,
except at those points where the piece was held
during the plunging, and these are afterwards coated
by means of a camel’s~hair brush. The glaze is also
removed with a knife and a piece of felt from those
parts which do not require it, such as the bottoms of
feet, necks adapted to the reception of covers, 850.
In applying glazes, the hands of the workpeople
must be entirely free from grease, or the glaze-powder
will not attach itself to those parts which are greasy.
Indeed, advantage is sometimes taken of this pro-
perty to perserve certain parts dull, such as delicate
Ornaments, 850., by touching them with a little oil or
a piece of fat, either of which acts as a resist. A
mixture of wax and fat melted together is sometimes
put on with a hair. pencil, in order to give precision
to the unglazed portion. Those parts of the piece
which require less glaze than the rest, may have a
portion of the glaze removed by gentle friction with
a brush.
' There are certain kinds of pottery-ware which, for

l
the sake of economy, are passed through the fire ‘only
once, and as pottery-ware in its green state is non-
absorbent, as is also the case with soft porcelain,
the glaze cannot be put on by immersion. The glazing
powder is mixed up with water to the consistence of
cream, and poured from a small vessel upon the piece
to be glazed, which is kept in constant motion, so as
to distribute the glaze equally over every portion of
its surface. In ‘some of the coarse pottery made at
Lambeth, of the yellowish-brown clay from Deptford,
(used without any admixture, or if too fat or tenacious
for certain purposes, brought down to the proper
state by admixture with loam,) the glaze is put on
with a brush; but for small articles, such as pipkins,
which are glazed on the inside only, a little of the
creamy mixture of glaze is poured in, and then poured
out again, a sufficient quantity adhering to the sur-
face by this process. The stone ware made at Lam—
beth from a mixture of pipe-clay from Dorsetshire
and Devonshire, calcined and ground flint, presents
certain peculiarities in the glazing. Custom requires
that the tops or bottoms of jars, and some other
vessels of this ware, shall be of a deeper brown than
the natural colour of the materials affords: they
are therefore dipped, as far as is required, in a mix-
ture of red ochre and clay slip. When dry, they are
piled in the furnace, with pieces of well-sanded clay
between the articles to prevent them from adhering.
A slow fire is kept up for 12 to 24: hours, according
to the thickness of the ware, capable of raising it to
a low red heat. The fire is then raised until the flame
and the ware are of the same colour: this is con-
tinued for some hours, during which the glaze is added
by pouring down the holes in the top of the kiln some
ladlefuls of common salt, the soda of which, as already
explained, forms a very thin but perfect glaze, suffi-
cient to render this compact ware capable of resisting
the percolation of water and strong acids. Large
vessels of this ware are now made for the manufac-
turing chemists, who use it instead of green glass for
distillatory vessels, Woulfe’s bottles, 850., some enor-
mous specimens of which were shown in the Great
Exhibition. Pickling jars, and other vessels, in which
acid substances are kept, and also those earthern
vessels in which great strength is required, are made
of stone-ware. The common pottery or cZe‘Zfi-wm'e,1
is also fabricated at Lambeth of the calcareous clay
or marl, of a blue, red, or yellow colour, from the
neighbourhood of Maidstone. The ware, formed in the
usual way, is converted into biscuit, which is glazed
in the following manner, as described by Mr. Aikin;2
Kelp and Woolwich sand are calcined together under
the kiln until they combine into a spongy imperfect
glass or frit: lead and tin are calcined together until
they form a greyish-white powdery oxide, called
by the potters tin and lead as/zes : the frit is then
ground dry, and afterwards mixed with the ashes, a
little zafi’re being added if a blue tint is required, and
arsenic if the glaze is intended to be white. The ‘com-_

(I) So named from the town of Delft, the centre of the Dutch
potteries.
(2) Illustrations of Arts and Manufactures, 1841.
- POTTERY AND PORCELAIN.
‘465
position, being well mixed while dry, is put into the
hottest part of the kiln, where it runs into a vitreous
opaque enamel. This is ground under a heavy iron
runner, and is finally mixed with water and rubbed
between stones, to the consistence of cream, into
which the biscuit is dipped, as already explained.
The glazes used for pottery have received a great
improvement of late years in the substitution of borax
or boracic acid for oxide of lead. Borax is whiter,
and gives sufficient hardness to the glaze to resist the
action of the knife, while it is free from the injurious
effects to the workpeople, which accompany the use
of lead. According to M. Arnoux, no less than
1,7 92,000 lbs. of borax, representing a value of
56,000l., are now used in the potteries. According
to the same authority, the glaze of the hard por-
celain is the pegmatite, not at all decomposed, and
of which some can be found which will alone give
a good glaze. At Limoges the glaze does not contain
other materials. If manufacturers possess only felspar
they must add some quartz, but such compounds are
never so good as those found in nature ; they have to
harmonize the glaze with the body by mixing some
portion of the latter with it, Thus, in hard porcelain
there is only one hard body, surrounded by a softer
one, melted one upon the other at a very high tempera-
ture. In Germany they do not use the felspar at all:
quartz is combined with lime, and harmonized by a
certain quantity of the body. The result is, in fact,
the same; instead of having as the former a silicate
of potash predominating, it is the silicate of lime.
These glazes are very bright, but greyish, and less
transparent than the others. The glaze of soft porce-
lain is wholly different, being a sort of glass, melted
previously in a reverberatory furnace, ground after-
wards, and mixed with oxide of lead or earthy
materials. It is generally a complex compound, al—
ways based on the property of borax or oxides of lead
to be vitrified into colourless glass at a low tempera-
ture. But as it would be too soft and liable to craze,
it is hardened with siliceous materials, such as flint,
felspar, or Cornish stone; and generally some carbo-
nate of lime is added. The soft porcelain requires
two firings, one for biscuit, the second for the glaze,
at a much ‘lower heat. For the hard porcelain a
single firing is used at a very high temperature.
The pieces are preserved from the direct action of
the fire in the glaze or gloss-oven by being packed in
seggars, as in the kiln. Care, however, is required
to prevent the contact of the‘pieces either with each
other, or with the seggar, or the glaze in a state of
fusion would adhere. In piling up the pieces in the
seggar, they are separated by means of pointed sup-
ports and rests, which are known by such names as
coc/rspars, stilts, triangles, &c., some of which are
shown in Fig. 17 21; and the method of arranging
flat pieces in the seggar is represented in Fig. 17 22.
The seggars are piled up in the glaze-kiln as in the
biscuit-kiln: the temperature is raised so as just to
fuse the glaze into a transparent glass and to enable
it to unite perfectly with the surfaces of the biscuit.
Vi’atches, or rings of clay covered with glaze, shown
VOL. II.

in Fig. 1721, are drawn out from time to time to
enable the workman to ascertain the state of the
furnace.




_;_.=-
llllhl
Fig. 1722.



Fig. 1721.
When the ware is to be ornamented with a pattern,
this is generally added before the glazing. For
example,——for printing the blue pattern of a com-
mon dinner-plate, a mixture of oxide of cobalt,
ground-flint, and sulphate of baryta, (fritted and
ground) is blended with a flux of ground flint and
thick glass powder, which serves to fix the colour.
The vehicle for making this preparation into a viscid
kind of printer’s ink, is a composition formed of
boiled linseed oil, resin tar, and oil of amber., The
colour thus mixed becomes sufiiciently liquid for use
by spreading it out upon a hot iron plate. From this
the colour is transferred, with a leathern muller, to
engraved copper-plates also made hot, the superfluous
colour being scraped off with a pallet knife, and the
surface cleaned with a dossil. The workman then
takes a sheet of yellow unsized paper, dips it in soapy
water, and lays it moist upon the copperplate, which
is then passed through a cylinder press. The paper
thus receives the pattern, and is handed to a little
girl, called the cutter, who cuts away the white un-
printed portion, leaving the pattern in its separate
parts. These are passed to the transjerrer, whose
business it is to transfer the pattern from the paper-
to the biscuit. This is done by placing the pattern
with the printed side next the ware, and rubbing it in
with a flannel rubber. At first this is done gently,
then more forcibly, until the colour is fairly trans,"~


; ‘I "I! ..
iW/lV/fl/ ///////'/
Fig. 1723.
TRAN SFERBING TH E PATTERN.
ferred. The articles thus treated are then placed in
a tub of water, and gently washed with a brush to
'get off the paper. The moisture is driven off by
the heat of an oven, and the articles are ready for
glazing. In some cases the impression is taken in
oil only from the engraved plate on a flexible sheet
of glue, called a paper or bat, which receives enough
oil to furnish two impressions to the biscuit, which
11 H
4.66
POTTERY AND PORCELAIN.
' certain proportions.
iferent proportions.
is then dusted over with colour in a dry state.
The glue can then be cleaned with a wet sponge,
dried, and used over again. When the biscuit thus
treated is put into the oven, the oil is driven off,
and the colour sinks in, and becomes incorporated
with the glaze.
Snctriolv IX.-—Pninriue on PORCELAIN.
Painting on earthenware and porcelain is performed
with a camel’s hair-pencil, and with colours such as
are used in enamel painting. These are all metallic
oxides, and are ground up with substances which
vitrify by heat, such as glass, nitre, and borax, in
The painting requires to be
several times retouched to give it due brilliancy. The
metals employed to produce the different colours are
——-For purple and violet, gold may be dissolved in aqua
regia, and a bar of pure tin be immersed in the solu-
tion. A precipitate is thus obtained, which is named
after its inventor, the purple precipitate 0f Cassius.
By dissolving the gold and the tin separately, and
mingling them in different proportions, various shades
of carmine, violet, and purple are produced. A red
colour is obtained from the suboxide of copper
C1120, and also from the red oxide of iron; the latter
oxide when calcined with double its weight of common
salt yields a permanent red. Yellow colours are
obtained from chromate of lead, sesquioxide of iron, an-
timoniate of potash, and also from white oxide of anti-
mony mixed with sand and oxide of lead. The oxides
of uranium and lead, when mixed, produce straw
colour. Blue is furnished by oxide of cobalt, also in
great variety from the oxides of tin and zinc in dif-
Green is obtained from oxide of
copper, from oxide of chromium, and from different
mixtures of Prussian blue and chromate of lead.
Various shades of yellow green are made by the
addition to the preceding of the oxides of antimony
and of lead. A brown tint is given to the green by
the sesquioxides of iron, and of manganese; blue, by
oxide of cobalt. To produce black, oxide of man-
ganese is employed, or several oxides may be mixed
to form the colour. Pure white is supplied by
one part virgin tin, and two parts common salt.
M. Salvétat 1 has recently proposed some new combi-
nation of metals for painting on porcelain. According
to him, a fine toned grey, superior to any other, is
obtained from 1 part platinum, in powder, and 3 parts
of a flux composed of minium 3 parts, sand 1 part,
melted borax g a part. He states, as a general pro~
position, that whenever the oxides of iron, or of cobalt,
or of the cobaltate of iron or of copper, are present in
small quantity with siliceous matter, capable of fusing
at the temperature to which the mixture is exposed,
the colour of the multiple compound is black; that
on the reactions which ensue depend the formation of
the various greys and blacks, the tones of which may
be varied by varying the respective proportions of the
oxides of cobalt, iron, and zinc, and. augmenting the
proportion of the flux. The blues prepared with

(1) Annales de Chimie et de Physique. 1849.

oxides of cobalt and of zinc are lively in’ proportien
as the oxides contain less oxide of iron. The reds
from oxide of iron, or oxides of iron and zinc, are
purer in proportion as such oxides are free from
foreign matters, such as manganese and copper‘. The
platinum grey above noticed is very useful to modify
the reds and ochres, and may be mixed with blues
without fear of producing a black. Palladium and the
other metals which accompany platinum ore may also
be usefully employed. Palladium grey is paler, and
ruthenium grey is redder, than platinum grey. The
sesquioxide of iridium is superior to all other blacks,
except the platinum.
The colours are pounded, and then ground with a
small quantity of oil on a glazed palette firmly bedded
in plaster on a wooden frame. Oil of turpentine, or of
lavender, is the usualvehicle for the colour and the flux,
the proportions of which are carefully weighed out
and ground on the palette with the volatile oil. In
painting, the right arm of the artist is supported on
a board projecting from the table at which he works,
while his left hand holds the article to be painted.
While painting, the appearance of the colours is often
dingy and unpleasing, but when the heat of a mode-
rate furnace has driven off the oil and other matters,
the colours are revealed in their natural brilliancy.
The enamels used in painting on porcelain involve
a number of general considerations of great interest in
a chemical as well as a practical point of view. It
will be seen that these enamels are vitrifiable com-
pounds attached to the surface of the porcelain by
the action of heat. They are fusible at a certain
temperature, depending on the fusing point of the
flux; and, as porcelain is much less fusible than
glass, a higher temperature may be ventured on.
Care, however, must be taken so to regulate the heat
as not to change the character of the metallic oxides
which form the artist’s pigments, nor to destroy the
general effect of the painting. When properly fired,
the colours have a smooth and brilliant appearance.
Some of these colours are opaque, others transparent;
but transparency is rather an inconvenience than
otherwise, since the white colour of the porcelain
.seen through them produces an enfeebling effect.
But in general, the enamels used in this art have
the same properties as enamels properly so called—-
the same hardness, the same indestructibility, a
similar resistance to friction, and a power of expan~
sion conformable to that of the substance which they
are intended to cover. The colouring matters are
also metallic oxides; the fluxes are silicates and
borates. It is usual to combine several fluxes
together, either for the sake of greater fusibility, or
for obtaining the desired whiteness. It would be
an advantage if the silicates used in compounding
fluxes were all insoluble, such as the silicates of lime,
alumina, and lead; but the necessity for having a very
fusible flux at command leads to the use of alkaline
silicates or borates, which are soluble. It is desirable
to combine them with other matters, so as to make
them as little deliquescent as possible. Lead fluxes
are preferred to all others on account of their more
POTTERY AND PORCELAIN.
467
equal powers of contraction and expansion as com-
pared with the porcelain to which they are applied.
The enamels used in this art may be arranged into
two groups, viz. first, those which derive their colour
from’the fusion of materials simply mixed together,
and secondly, those in which the colouring matter
combines chemically with the flux. The fluxes for
the first kind of enamels ought not to exert any
chemical action on the colour; while for the second
kind, the fluxes ought to form with them a true
chemical solution.
The proportions in which substances capable of
forming silicates are to be added must depend upon
the temperature which such silicates require for their
formation. The proportion of acid and of base
required varies with the temperature, and if the true
proportion be exceeded, the excess will remain un-
combined. The tendency of the silicates to unite
with the oxides increases with the temperature and
with the proportion of acid contained in them. A
flux will act upon an oxide at a given temperature if
the acid be in excess; but it will require a higher
temperature if the proportion of base be increased.
The composition of enamels depends on principles
such as these. For example, at a cherry-red heat the
basic silicates and borates of lead, of soda, and of
potash, have but a feeble action on the metallic
oxides. It is evident, therefore, that this tempera-
ture and those degrees of saturation of the bases must
be chosen for enamels of the first class, in which the
colouring matter is merely mixed with the flux. But
for enamels of the second class, where the colouring
oxides combine chemically with the flux, the latter
should have an excess of acid, or as much silicic acid
or boracic acid as possible, the temperature remaining
the same. But if the conditions of the painting
require a larger proportion of base in the enamel, the
reduced proportion of acid is met by employing a
higher temperature. The state of saturation above
indicated for enamels of the first class fulfils the con-
ditions required for the fluxes, both with regard to
the substance to be covered and the properties which
they ought to have in a ‘good enamel painting. In
enamels of the second class, the facility for supplying
the deficiency of acid by temperature, and vice acrsa”,
gives great latitude in varying the composition of
enamels, and greater scope to the artist.
The various colouring~matters employed in the
composition of enamels lead to important variations
in their physical characters, chiefly as regards their
dilatability; and it is only by varying the nature of
the flux that enamels can be made to expand and con-
tract within proper limits. This leads to the neces-
sity of employing various kinds of flux.
The fusibility of enamels varies with their state of
saturation; the larger the proportion of alkali, the
greater the fusibility ; the larger the proportion of
silica, the less the fusibility. In lead enamels the
yellow colour produced by the silicates of lead is in a
direct ratio to the quantity of base. The hardness of
enamels has the same relation to the bases as the
colouring. In the borates and silicates of lead, the

more the relative proportion of base is increased the
less stable are the enamels. The alkaline silicates
and borates, especially the former, have a tendency to
separate themselves from the plumbiferous silicates
and borates, which increases as the proportion of base
increases. At a high temperature they even undergo
decomposition, and the alkali becomes volatilised. If
we descend to the degree of saturation of the bibasic
silicate, the compound is so much acted on by moisture
that the alkaline silicate will dissolve in cold water.
For this reason potash is not employed in painting on
porcelain, since, in order to render enamels sufficiently
fusible, and to give them the required powers of
expansion, the proportions of potash required would
render the enamels very subject to change. This
inconvenience is got rid of by the substitution of
borate of soda, which is more fusible under the same
circumstances than silicate of soda or of potash, and
thus the required fusibility may be obtained without
lowering too much the degree of saturation. The
effect of this is to diminish the yellow tinge and the
liability to change, and at the same time to increase
the hardness. _
There are two methods of preparing enamels. For
those of the first class a flux rich in base is selected,
and in order to diminish the risk of exposure to a
high temperature, the colouring matters are united
with the flux by the process of porphyrisation, so
that the mixture is not heated until it has been pro-
perly applied to the porcelain. No more flux is
added than is required in order to give to the enamel
after firing a smooth and brilliant effect. For enamels
of the second class, the flux must have as large a
proportion of acid as possible, and it must be present
in as large a proportion as is consistent with the re-
quired intensity of colour; llzz'z'clly, the oxide must
be free from any substance likely to interfere with
its complete combination with the flux; foarlkly, the
enamel must be fused before being applied,
For enamels of the first class, the colouring matter
does not always consist of a single oxide, but gene-
rally of several oxides combined, the object being to
procure the colour due to their union; or to impart
to one of the oxides a fixity, which it does not possess
alone. So also in enamels of the second class, several
oxides may be employed as well for the purpose of
favouring solution as for obtaining the required
colour. In enamels of the first class, two oxides
are frequently combined, since the stability of the
resulting compound resists the action of the flux.
In enamels of the second class, two oxides are com-
bined for a .contrary reason; their union not being
very stable, they are in ;that state of division which
is favourable to complete combination with the flux.
With this view, it is desirable to prepare these
enamels by heating the colorific oxide with the ele-
ments of the flux, rather than with the flux previ-
ously vitrified. In such case, the oxide of lead,
which is always one of the constituents, attacks the
colouring oxide, reduces it to a state of minute
division, dissolvesit, and thus prepares it for its
union with silica.
n H 2
Z£68
POTTERLAND PORCELAIN.
Enamels used for painting on porcelain are similar
to those used for painting on glass; but they are
more numerous, since porcelain admits of opaque as
well as transparent enamels, being employed. Hence,
in porcelain enamels of the first class, much use is
made of the oxides of tin, antimony, and zinc. They
have the advantage of fixing other colouring oxides,
of imparting to enamels their own peculiar tints of
white, and that opacity which is often useful to the
painter on porcelain, but could not evidently be
used on glass. For example, clear lzlue, or azure
blue, is obtained by a mixture of oxide of zinc or
of tin with oxide of cobalt. Emerald green by oxide
of copper and antimonic acid. In these cases stan-
nic acid, antimonic acid, and oxide of zinc soften
down the blue and green by their own proper
white tints. Most of the yellows are obtained by the
antimoniate of iron, of lead, or the zincate of iron.
These are cases in which the antimonic acid and the
oxide of zinc are especially employed to give stability
to the oxides to which they are united. The yellow
enamel, coloured by chloride of silver, is used only
for the purpose of lighting up or brightening the
purples. Porcelain does not admit of being coloured
by cementation as is the case with glass. [See
GLASS, Sec. IX]
"With respect to the composition and preparation of
the fluxes, we must refer to the article ENAMEL.
Several of the metals are used in ornamenting por-
celain without the intervention of a flux, or without
being converted into oxides. The gold employed in
gilding porcelain is first dissolved in aqua regia ; the
acid is driven ofi by heat, and the gold remains in a
minutely divided form, or the gold may be precipitated
by means of sulphate of iron. The gold in this pul-
verulent state is mixed with 715th of its weight of
oxide of bismuth with a little borax and gum-water,
and applied to the edges of the ware with a pencil.
Articles which have to be ornamented with a circular
line only, are placed on a whirler. Fixing the article
upon the circular head, the workman applies the
pencil to it with one hand, kept steady by means of a
rest, while with the other hand he causes the circular
head to revolve. The effect is thus produced with
great exactness. The articles thus ornamented appear
dingy when first baked, but the lustre of the gold is
brought out by burnishing, first with agate, then with
blood-stone. This is done by a female, who uses the
burnisher lightly and in one direction, not to scratch
the gilding. The burnishers are of various forms


~Fig. 1724.
and sizes, as shown in ‘Fig’. 1724*, to suit the forms of
the articles operated on. A little vinegar or white-
lead is also used to clean the gilding. Some years

ago the weekly consumption of gold for the gildirTg
of porcelain in the borough of Stoke-upon-Trent
was estimated at 650l. sterling, or 35,000l. per
annum.
Metallic lustres applied to stone ware consist of
metals, which, like gold, do not readily oxidize.
Silver lustre is obtained from platinum, and has a
silver white hue; there is also a platinum lustre re-
sembling polished ~steel. For the former, the metal
is dissolved in aqua regia, formed of equal parts of
the acids, and the saturated solution poured into
boiling water. On pouring this into a Warm solution
of sal-ammoniac, the metal falls down as a yellow
precipitate, which is to be well washed with water,
and dried. It is applied'to the ware by means of a
flat camel’s-hair brush, after which it is passed
through the mufiie kiln. The operation may require
to be repeated to obtain suificient body of lustre. If
the articles come out black from the kiln, friction
with cotton will restore the proper colour. For the
platinum steel lustre the metal is dissolved in aqua
regia, composed of two parts muriatic acid, and one
part nitric. When the solution is cool, there must
be dropped into it, agitating all the time with a glass
rod, spirit of tar, composed of equal parts tar and
sulphur, boiled in linseed oil and filtered. If the pla-
tinum solution be too strong, more spirit of tar must
be added; if too weak it may be concentrated by
boiling. The mixture being spread over the piece,
and passed through the mufiie, it will assume the
appearance of steel. Gold lustre is obtained by pre-
cipitating a solution of gold in aqua regia by means
of ammonia. The precipitate, which is fulminating
gold, is mixed while moist, with essential oil of tur-
pentine, and it is applied to the surface of the ware
without a flux. After the firing the lustre is brought
out by friction with linen. The remarkable ‘iridescent
lustre, called by the French lustre cant/amide, is ob-
tained from chloride of silver, the partial decomposi-
tion of which is determined by combustible vapours.
A mixture, made of a lead glass, a small quantity of
oxide of bismuth, and chloride of silver, is applied by
a camel’s-hair brush to the ware, which is then heated
in the mufile kiln. When at a red heat, a fuliginous
smoke is introduced into the muffle, which produces
the desired partial decomposition. An iron lustre
may be obtained by dissolving iron or steel in muriatic
acid, mixing the solution with spirit of tar, and ap-
plying it to the surface of the ware. Silver and pla-
tinum lustres are commonly laid upon a white ground;
gold and copper lustres succeed best on coloured
grounds. The paste body for lustrous ware is usually
made on purpose,'and is coated with a lead glaze
composed of 60 parts litharge, 36 of felspar, and 15
of flint. The paste body is brown, and consists of
4: parts clay, 41 of flints, 41 of kaolin, and 6 of fels—
par. .
. he firing of painted porcelain is a delicate opera-
tion, and is conducted in a muffie furnace, shown in
section, Fig. 1725. The heat is regulated according
to the indications afforded by small watches of por-
celain, painted with some of the enamel colours
POTTERY AND PORCELAIN.
4:69
employed on the ware, those being preferred which
' - , -. aremost susceptible
(Q of change or injury,








)1
(I I
~‘ r.
ffikX th ' lo r' for
\. ,2, ggggwg , gig; e lose co u s
.—. ‘sniff-Th‘ i example; and gold
H 1:: ' {l ' W 34?‘ lustres, &c. which
l "7"“ require a‘ high tem-
perature for their
adhesion. Conse-
quently, the fire
must be so regu-
lated as to conform
. to these and other
. - .. ' I?’ conditions. The por-
. , celain dmust . be
HI‘ I ply“, p as s e t w 1 c e
lll lhgjht s 101 ~ o'h th fi~ -
: .-~. :1: and‘!!! nous e 1e‘
T§§\\\ . the first firing is
rather a trial than
P141725- an actual result : it
enables the artist to see what is wanting in the ap-
plication of the colouring oxides, &c., and having
retouched the parts requiring it, it is passed a second
time through the muffle. A third, or afourth firing
may even be required for large and elaborate works.
The muffles are made up of tolerably good clay, sup-
ported on fire bricks, and heated from the outside.

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Sncrron X.—-On DESIGN IN Por'rnnr AND Pon-
cnnxrn.
If it be true that “fictile fabrics alone will often
mark the standard of national civilization, and indi-
cate the progress of a people in the arts of life,”
then it must be felt by many a student of - the pottery
and porcelain displayed at the Great Exhibition, that
several nations are making great and contemporaneous
advance at the present day, and that Great Britain is
honourably distinguished in the friendly rivalry. The
general system of the porcelain manufacture has been
improved, and in very many cases a better taste has
been introduced in the various modes of ornamenta-
tion. Merely ornamental works in pottery and por-
celain appear unsuitable, and at variance with the
natural purposes of so eminently useful a material;
and we suppose that'few persons could persuade
themselves really to admire the imitations, of beau-
tiful flowers, far less of fish, and even reptiles, which
were cleverly executed in high relief in the centre
of dishes and baskets, of this fragile material, and
conspicuously exhibited in the foreign department.
The more exact the imitation of animal life, the more
unpleasing the effect; in fact, there was something
monstrous in the idea of an ornamental dish, over
the surface of which frogs and lizards in all their
green and yellow ugliness were preparing to leap or
crawl. Such instances of bad taste were not, how-
ever, frequent, although purely ornamental subjects
in porcelain, most elaborately decorated, were to be
found in several departments. These are defended
by Mr. Redgrave, in his Report on Design, on the
ground that when works are prepared simply as
ornaments, they may not only be admired as addressed

to the purpose of giving pleasure by their beauty,
but because they often insensibly exercise a useful
influence on the general taste of the manufacture.
This he illustrates by referring in the following
terms to that most interesting and valuable collection
of porcelain in the Sevres Court:—~“Here we find
the taste of the first artists, assisted by the science
of able chemists, and under a judicious direction,
united to the most skilful workmanship and manufac-
ture, and the result is that the manufacture of por-
celain is carried to the highest state of excellence.
The greatest part of the display, however, consists
of works which must be classed as ornaments, such
as vases, caskets, chalices, tazzas, &c. The forms
adopted are pine, and those pure forms rarely inter-
fered with by the reliefs. The details of the decora-
tion, the modelling of the reliefs, and the painting—
whether these consist of figures, flowers, or simply of
ornamental forms—are of rare and felicitous excellence
in many cases, and of high merit in all. The finished
perfection of these choice works must have exercised
a great influence on the other manufactures of the
country, not only by forming a band of workmen
educated to perceive excellence as well as to produce
it, and capable of giving assistance in many other
branches of manufacture, but by their effect on the
general cultivation of the public taste. Nor do such
establishments benefit the country that supports
them alone, they diffuse taste abroad, even in other
lands. Thus the improvement of our own general
manufacture of china has already been advcrted to, and
yet it is but justice to say that it owes much to‘the
labours of the national establishments both of Sevres
and Dresden; not only that their works have in some
cases served as our examples, or guided our manu-
factures by the principles of their decorative treat-
ments, but from the stimulus to improvement which
has resulted from the contemplation of rare works,
and of that perfection which arises from a manufac—
ture occupying itself rather upon efforts of skill
than upon general production, and able to employ
itself upon them irrespective of expense, and regard-
less of cost.”
The abuses of the system of mere ornamentation,
are, however, distinctly pointed out, as shown in some
of the works of the Dresden manufactory. “The
surface,” says Mr. Redgrave, “is often covered with '
purely imitative flowers in high relief, glowing and
brilliant as the tints of nature, yet looking gaudy as
ornament, and from their-filmy projections, liable to
injurywith every touch, and their preservation a source
of constant anxiety to the possessor. Even the May-
flower pattern—.-a production of great beauty, on the
principle of a diaper of form and colour—from its
minute hollows, is quite incapable of being cleansed,
and from the thickness which it adds to the form,
contradicts the true effect of porcelain, which should
unite lightness with capacity.” 'The skill and taste
of English artists have not yet been fully exercised
in reference to pottery and porcelain. Beautiful
works in enamel show what they are capable of, but
enamellers are not connected with the pot-terics ;
470
ror'rnnr AND PORCELAIN.
whereas in foreign countries, where the nation pays
for the best means of improving the porcelain manu-
factory, the services of the most skilful and eminent
men are eagerly sought. “ In England our china-
painters are not artists, and but few of; them seem to
have artists’ feelings, nor until of late years have
they had the opportunity of 'gaining the necessary
instruction. The painters on "china copy fruit, foliage,
and flowers well; but when such labours are original,
they too often consist of but slight variations of some
stock and stereotyped forms and colours which the
workman uses over and over again, without novelty
either in grouping or drawing. In the power of
painting the human figure they are mostly deficient,
and few of them are able to execute subjects of
which flesh forms a part. The modellers have also
been sadly deficient in knowledge of the figure, and
of its anatomical details. In both these particulars,
however, they are slowly improving, and the intro-
duction of Parian and other materials for statuettes,
which is beginning to form a large branch of business
in the potteries, and which as yet is nearly peculiar
to England, has been of service in showing them their
defects, and in urging them to amend them.”
To the above remarks, the truth and justice of
which must commend themselves to every one ac-
quainted with the subject, we would willingly add
some judicious suggestions on what may be called
the common sense of designs in pottery and porcelain.
A single extract is all that our limits will allow of,
but the whole, as contained in the Jury Report,
(pp. 733, 734s) is well worth the attention of manu-
facturers and designers. The most elegant forms
in vessels of capacity must be united with the most
convenient adaptation to use, and with the readiest
means of cleansing; otherwise the mere elegance
will not atone for daily and hourly annoyance in other
respects. “It is to be remembered that the means
of receiving that which is to be contained, is as
necessary as its ready outpouring; since it is hardly
necessary to have to apply a funnel to fill a pitcher or
jug intended for constant use, although this may be
permitted in a bottle, which is required to keep its
contents cool, or to be carried about, and subject to
spill them by jolting, and therefore needing a smaller
aperture. Moreover, a jug or pitcher, which will
admit the hand to cleanse it thoroughly, must
be more suited to daily use than one which will
not. A due consideration of utility would regulate
the form in many other cases; as, for instance, in
cups and other drinking vessels, it might be most
graceful to curve the top edge outward, but since
such a form is likely to overflow the person in drink-
ing, however superior in elegance, it should not be
adopted. When utility is considered before ornament,
numerous truths of the like kind will he arrived at,
which are entirely overlooked when the order is
reversed; thus relief, when used, should be extremely
low, and without indented hollows in the composition,
as well as without undercuttings, in order to give faci-
lity for cleansing: but while this is required for utility,
it is necessary for elegance and beauty also. The

Greeks were fully aware of it as an important truth;
and in their pottery abstained from reliefs, or kept
thein at the lowest impost. The vases of Etruria
have generally their line unbroken by the ornament,
and the reliefs on the celebrated Portland vase are so
extremely low as entirely to preserve its outline.” Mr.
Redgrave illustrates these and similar remarks by an
engraving of an antique enamelled flower vase, where
taste and convenience are both consulted, and also
gives a sketch of difierent forms of Etruscan vases,
originally intended for two handles, but now used
with one,’ to the inconvenience of the possessor,
showing with how little thought adaptations of
classic forms are introduced at the present day. Our
own experience accords with this statement. A ewer
of tall and elegant form having proved extremely
inconvenient from the fact that the handle is placed
too high up, (no deviation having been made from the
original pattern vase, except in converting the second
handle into a lip,) and thus the water cannot be poured
out without the use of both hands. Mr. Redgrave
justly reprobates the employment of sacred symbols
as ornaments of vessels in common use, and quotes a
wise remark, that “ symbolical ornament demands
perfect accordance between the use of an object and
its decoration.” This will at once condemn Scriptiu'e
sentences on bread platters, figures of the apostles
as ornaments for jugs and spoons, and numerous
other well-meant attempts at symbolical ornament.
While there is much imperfect taste to be cor-
rected, and much further knowledge to be acquired,
yet we are undoubtedly making steady national pro-
gress.
The results of the Great Exhibition show a great
advance made by England in ceramic manufactures.
The classic beauty of many of the designs, and the
admirable execution of the works exhibited by the
firms of Minton, Copeland, Wedgwood, Ridgway,
Mayer, and others, give the highest promise for the
future. The great difficulty in the present state of
things, when a constant and increasing demand has
to be met by the labour of the potteries, is to find
time for study and invention. This is well alluded
to by a distinguished juror, and patron of the ceramic
art. “ Commerce wants rapidity of design and exe-
cution, cheapness, convenience of form, colours
at the same time lasting and attractive, eternal re-
ference to the ledger account: on the other hand, art
needs, genius, education, original conception, accurate
drawing, chemical science, the power of remodelling,
and remedying defects and flaws, refined taste, and,
above all, time and money; so is created a perpetual
conflict between art and manufacture. The tenden-
cies of the age to save labour, to lessen expense, and
to multiply production, are abstractedly all adverse
to the development of taste, and I often think what
advantages to art would be gained, if more breathing-
time could be afforded to genius, by the establish-
ment of cities of refuge in Italy and Greece, where
artistic feeling could fly for peace and repose, and
perfect, under a warmer sun, the education of the
student’s eye, freed as he then would be from the
PRECIPITATE—PRINTIN G.
4:71
trammels with which he is now encumbered, working,
as he too often does on his own account, for his own
daily bread.” 1
POUND. See Wnren'rs and Museums.
POWER—Mecnxnrcxn Pownns. See S'rxrrcs
and Drnxnrcs.
PRECIPITATE, a substance separated from
a liquid in minute particles, which subside to the
bottom of the vessel. “ Precipitation is valuable as
a mode of separating substances, and consists in
changing them from a soluble into an insoluble state.
It always depends upon altering the relation of the
solvent to the substance it holds in solution; this
being effected sometimes by changing the state of the
solvent, as when water is added to a solution of resin
in alcohol, or alcohol to a solution of gum in water;
and at other times by causing a change in the body
dissolved, as when sulphuric acid is added to a solu-
tion of baryta to precipitate the earth, or ammonia to
a solution of iron to precipitate the oxide. It is often
practised to render the presence of a substance visible,
and forms an essential part of analytical and other
processes, as well in the discovery of bodies, as in
their separation and estimation. Any substance added
to a solution to cause a separation in the solid form
of matters present, has received the general name of
precipiiaal, and the substance so separated is called
a precipitaiam
PRESS. See Hrnnosrx'rrcs and HYDRAULICS—
CoINrNe—Oms and FATS—PRINTING—SCREW, &c.
PRINCE’S METAL (named after Prince Rupert),
an alloy of copper and zinc, containing more copper
than brass does, in which respect it resembles Tombac,
Dale/i yolcl, Similar, and PINCHBECK. See BRASS.
PRINTING. The art of printing, in its usual
sense, is a mechanical process by which any piece of
literary composition is multiplied by means of types,
ink, and paper. The art consists essentially in the
production of copies by means of pressure. This
latter definition would include the taking of impres-
sions in clay, wax, &c. by means of cameos and in-
taglios; and such is an example of multiplying copies
by pressure only; but in printing, as it is commonly
understood, an ink or pigment is always transferred
from the stamp or type to the paper or other substance
destined to receive the impression. The impressions
or copies produced by printing are not, however,
exact copies of the original stamp or type, any more
than the wax impression of a seal is a copy of the seal
which produced it. Simple as this fact may appear,
it nevertheless constitutes one of the chief difficulties
in the art of printing and engraving. The raised sur-
face of the stamp or type is sunk in the copy, and its
form is also reversed; that is, all those parts which
are on the right-hand in the stamp, are on the left-
hand inthe copy, thus requiring that in setting up the
type all the lines shall begin on the right-hand of the
page, in order that they may commence on the left-
hand in the printed copy. Of the various kinds of

(1) Lecture delivered in January 1853, by C. B. ‘Vall, Esq. Ml’.
before the Literary and Scientific Society of Salisbury.
(2) Faraday. Chemical Manipulation.

printing, the most common, as well as important, is
lcli‘er-press prialiag, in which impressions are taken
from letters and characters cast in relief in separate
pieces of metal. Wood engravings are also cut inre-
lief, and they print in the same way as moveable types.
Ccppcryalaic printing is the reverse of letter—press:
the characters are sunk or engraved in intaglio, and
the pigments or inks are contained in the lines of the
engraving, below the general surface. Hence, while
in letter-press printing the letters or lines are pressed
into the paper, in copper-plate engraving the paper is
forced into the lines or letters of the copper-plate.
There is yet a third mode, called surface-printing, of
which lii/zograp/zy and ziiicqr/rap/iy are examples, in
which the lines or letters are written or drawn on the
surface with pencils of a peculiar kind, the marks
produced by which will take up the ink from an
inked roller passed over them, while the ground on
which the letters are written refuses to combine with
the ink. [See Enenxvrna] Calico is printed from
surfaces engraved in relief or in intaglio. [See CALICO-
PRINTINGJ In the present article our attention will
be directed to letter-press printing.
Sncrron I.—~Ilrs'ronrcxr. Norrcn or Pnrnrnve.
It must surely be regarded as an astonishing cir-
cumstance, that an art so admirably calculated to
advance the true interests of mankind, and yet so
simple in its essential characteristics, should have been
discovered at so late a period as the middle of the
fifteenth century. It is impossible to say when the
germs of the art did not exist. A man could not
walk along the sands of the sea-shore without multi-
plying the impressions of his footsteps. Seals and
signets are repeatedly mentioned in the Old Testa-
went, and were in common use among all the civilized
nations of antiquity. The Assyrians printed inscrip-
tions on the clay which had been moulded for the
bricks employed for building, and the Romans were
accustomed to stamp inscriptions on pigs of lead and
other articles of their manufacture. The Chinese
method of printing, as practised from a very remote
period, would seem to require only to be known to
a nation possessing an alphabet, in order at once to
suggest the art of printing with separate pieces of
metal capable of unlimited combination. According
to the Chinese method, smooth blocks, of a firm close-
grained wood, were reduced to the size and form of
the page of the intended book, and on one side was
glued a piece of paper on which some able penman
had transcribed the words intended to be engraved.
An engraver then cut out the characters in relief, and
the remains of the paper being rubbed off, the engraved
tablet was ready for printing. Thus in printing a
book there were required as many blocks as there
were pages, and as no block could be used in printing
other books, the process was tedious and expensive.
It had its advantages, however, in requiring no cor-
rection of the press; and forming, as it did, a kind of
direct stereotyping, a portion of an impression could
he worked off as it was wanted. The books thus
472
PRINTING.
produced are said to be accurate and beautiful, but not“
durable, on account of the bad quality of the paper
and ink employed.
It is remarkable that the first essay in printing in
Europe was by means of blocks such as these; but
there is not sufiicient ground for the belief that the
idea was suggested by the Chinese. It appears that
about the year 1400 playing cards and manuals of
popular devotion, which had previously been manu-
factured by hand, were now produced by means of
block-printing. The manuals, like the cards, mostly
consisted of .a single page, but sometimes of several
pages. .The era of these block-prints and Heels-books,
as they are called, was the first half of the fifteenth
century; and during the time that they were in com-
mon use, the idea probably occurred to many inge-
nious minds of cutting up one of these blocks so as
to have separate letters for newcombinations of words
and sentences. Indeed, this separation of the letters
had already been done for the eye in the common
born-look, or A-B-C-book, from which children learned.
their letters. And the execution of such an idea has
actually been claimed by the Dutch, for one of their
countrymen, Lawrence Coster, of Haerlem, who is
said, about the year 1430, to have printed by means
of “ separate moveable wooden types fastened together
by threads,” and that “ his press was shaped like the
common wine-presses.” He is reported to have kept
his art secret for about ten years, when, in 1440, one
of his servants stole his types and the necessary appa-
ratus, and after having visited Amsterdam and Cologne,
settled at Mentz as a printer. These details, however
gratifying they may be -.to national vanity, rest on
a very slender foundation; but even supposing that
Coster did print with moveable wooden types, he was
far from having produced the art of printing in its
useful practical form, for that requires the production
of metal types by the cheap and rapid method of
casting; but types cannot 'be cast without a matrix
or mould, and a mould cannot be formed without a
punch or stamp of hardened steel; so that if it be
admitted that Coster succeeded in printing with move-
able types of wood, then that worthy triad Guten-
berg, Fust, and Sch'ciffer, whose story is briefly given
in our article Enenxvrne, can only claim the honour
of having improved the art; but they are improvers
of such a character, that they bear to the art of print-
ing the same relation that Watt bears to the steam-
engine. We are, however, on a careful examination
of the confused mass of evidence 'before us, disposed
to reject the claims of Coster and to admit those of
Gutenberg, Fust, and Schtiffer, in the order in which
we have written them down. Coster is said to have
imagined the art from having engraved certain letters-
and words on the bark of trees during his afternoon
walks, ‘ and having filled up these engraved letters
with a viscid kind of ink, he found he could take
impressions on' paper from them, and that in this way
he actually printed lines and couplets for the benefit
of his friends. . This process is certainly a step in the
rear,—'-for with the full knowledge of the art of print-
ing with blocks and of common engraving, why should

he adopt the very rude method of printingvfrom the
bark of trees? and, moreover, if it were his fancy to
mutilate the trees which adorned his path by carving
words upon them, he must have arranged the letters
the reverse way, or they would be of no use to the
reader when printed. Then, again, when he had per-
fected his art, and was practising it for profit, the
books which he produced must have excited the ad—
miration of the learned, if not by their beauty, at least
by the extraordinary facility and cheapness of their
production; but this is nowhere stated, and it is not
even pretended that a single copy of any one of
Coster’s books is in existence; whereas Gutenberg,
Fust, and Schofl'er, have left abundant evidence of the
genius and industry with which they have benefited
mankind. Then with regard to the robbery by Coster’s
servant, there is some mystification about the name
of the thief. He is referred to as J an -———; and
some writers who advocate the claims of Holland,
have had the audacity to fill up the blank first with
the name of Gutenberg and then with that of Fust.
Gutenberg was a gentleman, who expended the whole
of his private fortune in endeavouring to perfect the
art, and Fust was a goldsmith; both men of consider-
ation in the town where they resided. It is stated
that Coster had such a demand for his books, that he
kept two or three men constantly at work; that while
he and his family were at their devotions on Christmas
Eve, M40, this J an -—~-- ran off with his types,
850. It seems to have escaped the notice of Coster’s
advocates, that 1440 is the year in which all writers
agree that Coster died at the age of 70: but sup-
posing it to be true, as some have asserted, that
Coster died broken-hearted at the loss of his types, is
it not remarkable that within one year of the robbery
we should hear of the thief, still nameless, being
settled quietly at Mentz, and producing works of
repute, the titles of which are given, with the iden-
tical letters which he stole from Coster, and yet that
Coster in ten years should have produced nothing
with the said types, at least nothing which has reached
us, not even a title, except the Spieyal eraser lie/wu-
clerzz'sse, _of which it is doubted whether blocks or
moveable types were used in its production? We may
now dismiss this claim with the remark, that it was
not made until about the year 1568, or 128 years after
Coster’s death, when it was brought forward by the
historian Adrian Young, or, as it is pedantically ren-
dered, Hadrianus Junius, who had heard it from his
tutor, Nicholas Galius, who ‘had. heard it from a book-
binder, who had worked for Coster.
Of a very different character are the claims of
Gutenberg and his companions. Gutenberg, sur-
named Genzfleisch, Gensfleisch, Gensefleisch von
Solgenloch, was a native of Mentz (or Mayenee, as
we write it, after the French fashion of changing all
proper names), and of noble family. He is said to
have resided for some years at Strasbourg, where he
practised the art of printing with moveable types,
which he endeavoured to keep secret. About the
year 14:50, he returned to his native city, where he
sought the aid of John Fust, a wealthy goldsmith,
PRINTING;
4:73
with whom he entered-into partnership: ‘he hired a
house, and took into his employment Peter Schofi'er
and others. Sch'cifi'er appears to have been a scribe,
one of that valuable class who produced books of
great beauty by the costly and tedious process of
transcribing. He was now engaged in a pursuit which,
if successful, would annihilate his profession. In
lending his aid to the new undertaking, he knew
what was required by learned men, namely, books
produced with increased facility and economy, but
not so different in style and appearance from those
already in use as to shock the conservatism of the age
by too startling a novelty. Fust, as a worker in
metals, would be able to bring all the resources of
his trade to bear upon what we may fairly conceive to
have been Gutenberg’s leading idea, viz. the pro-
duction of moveable types in metal. In his earlier
efforts at‘ Strasbourg, Gutenberg formed his types by
carving or chasing them out of separate pieces of wood
or metal; but one of the first results of the partnership
was to cast the types in moulds of plaster, and finish
them off by hand. But the plaster was too soft a
material for the purpose, and the haud~labour slow
and costly, for an ordinary mechanic could not be put
upon such delicate work. As a stimulus to invention,
Fust is said to have promised his daughter in marriage
to Schoffer, on condition of his perfecting the inven-
tion; and the result was the cutting of metal punches
and the formation of matrices, thus giving to the art
all its essential elements. The works which were
issued from their press, numerous copies of which
still remain, are remarkable for taste and beauty,
and eminently justify the claim of these three dis-
tinguished men to the honour of having invented
the art of printing with moveable metal types, pro-
duced by casting in metal moulds formed with steel
punches. After working together for some time, the
partners disagreed, and went to law; and we learn
from legal documents that Gutenberg had expended
the whole of his considerable private fortune in his
experiments, and had mortgaged his printing materials
to Fust. In 14:65, he abandoned the art which had
proved so ruinous to him, and entered the service of
the elector, Adolphus of Nassau. He died February
Qétth, 14168. His printing~ofiice and materials had by
this time passed into the hands of Conrad Humery,
Syndic of Mentz, who sold them to Nicholas Bechter-
munze of Elfried.
Within eighteen months of thedissolution of part—
nership, viz. in August, 146:7, Fust and Schoffer
produced the celebrated Psah‘er, printed with large
cut type. This is the first book that bears the name
of the place where it was printed, the name of the
printers, and the date of the printing. In 14:60 was
printed the celebrated Latin Bz'éle. Fust died at
Paris in M66, where, in consequence of selling his
books in such abundance, and at a rate so very much
below that of the transcribers, he is said to have been
accused of calling in the aid of the enemy of mankind
to assist in this rapid production. Hence arose the
stoiy of the Devil and Dr. Eaustus—a curious part-
nership truly, considering that the works produced by

this firm were Bibles and Prayer-books! ' Scholfer
survived his father-in-law many years, and, in con- -
junction with Conrad Henlif, produced a great
number of works, which, with those previously pro—
duced, exceed fifty in number. Henlif’s name is
in the colophon of the fourth edition of the Bible
of1502.
The capture of Mentz, by Count Adolphus, of
Nassau, in M62, interrupted the labours of Fust and
Schofi'er, and probably compelled a number of work
men initiated in the mysteries of the art to seek refuge
in neighbouring states, and thus to diffuse a know-
ledge of its practice. It had already acquired such
fame that every person in Europe pretending to lite-
rary skill sought for information respecting it. The
eagerness with which the new art was welcomed and
adopted, in days, too, when the march of improvement
was very slow, may be judged of from the fact that,
within six years of the publication of the Psalter, the
art had extended to several cities which were in con-
nexion with Mentz, and within fifteen years to every
considerable town of christian Europe. This rapid
progress is to be attributed not a little to the fact
that the works of nearly all the early printers were
devoted to religion or learning, whereby the new art
was raised in the estimation of all men. When the
art was introduced into England it was first practised
in a chapel near Westminster Abbey, a circumstance
which has been perpetuated by the technical applica-
tion of the word chapel to every printing-oifice to this
day 3 and when the men meet together for the purpose
of considering or framing rules and regulations for the
good order of the printing-office, they are said “to
hold a chapel.”
Caxton was the first English printer. It is asserted
that, during his residence in the Low Countries, be
secured the services of one of the fugitive printers of
Mentz, and established a printing-oifice at Cologne,
where he made the acquaintance of Wynkyn deWorde,
Theodorick Rood, and of his countryman, Thomas
Hunte, who all afterwards became printers in England,
the first-mentioned accompanying Caxton to England
when he removed his printing materials from Cologne.
The first book that was printed by Caxton on his
arrival was the Game of C/zess, which was completed
on the last day of March, 1474:. In the work which
preceded this—the printing of which was finished at
Cologne—Caxton takes care to explain to his readers
that the work is printed, “not wreton with penne and
inke, as other bokes ben, to thende that euery man
may have them attones (at once), fl’o‘r all the books of
this story, named the Recule of the historyes of
Troyes, thus enprynted as ye here see, were begonne
in con day and also fynished in con day.”
We get some idea of the early printing-presses from
a device of Badius Ascensius, of Lyons, 1495—1535,
inserted on the title-pages of his books in various
sizes. It appears that this press could only print four
pages at a time, and that at two pulls. The table and
the tympan ran in, and the plattin was brought down
by a powerful screw by means of a lever inserted in
the spindle.
474.-
PRINTING.
The colour of the ink in the early printed bdoks
varied considerably. The earliest copies of the Spe-
culum and the Biblz'a Pauperzmz were printed in inkof
a brown colour, of which raw umber is the principal
ingredient. This colour harmonized better than black
with the adornments which were afterwards added by
the illuminators. Eust and Schoffer introduced black
ink, and must have been skilful in compounding it,
since their works still possess depth and richness of
colour. The same colophons which give representa-
tions of the presses show the method of applying the
ink to the types by balls of skin stufled with wool, a
plan which continued in use up to within a few years.
The ink was laid in some thickness on the corner of a
stone slab, and thence taken in small portions, ground
with a muller, and so taken up by the balls and applied
to the type. The types were disposed in cases similar
to ours, but the composing-stick was somewhat
different. In the early pictures of printing-oflices
pictorial effect is studied rather than propriety of
arrangement; for in one room are represented the
operations of casting the type, composing, reading,
and working, operations which would evidently be
distributed in different rooms. The early printers
were too careful to preserve the beauty of their works
not to have adopted this arrangement.
These early productions were, in form, generally
large or small folios, or quartos; the lesser sizes not
having come into use. The leaves had no running
title, numbering of pages, or divisions into para-
graphs. The character was a rude old Gothic, mixed
with Secretary, intended to imitate the handwriting
of the time; the words were so close together as to
make it difficult to read them; the orthography was
various, and often arbitrary, disregarding method.
There were frequent abbreviations, which in time
became so numerous, that in order to understand
them, it was necessary to have a book specially
devoted to their explanation. Periods were only of
two kinds—namely, the colon, and the full-point;
afterwards an oblique stroke was introduced, thus, / ,
which answered the purpose of our comma. No
capital letters were introduced to begin a sentence,
or for proper names of men or places. Blanks were
left for the places of titles, initial letters, and other
ornaments, in order to have them supplied by the
illuminators, whose ingenious art did not long survive
the improvements of printing. Those ornaments were
exquisitely fine, and curiously variegated with the
most beautiful colours, and even with gold and
silver; the margins likewise were frequently charged
with a variety of figures of saints, birds, beasts,
monsters, flowers, 850., which had sometimes relation
to the contents of the page, but often none at all.
These embellishments were very costly, but for those
who could not afford a great price, there were inferior
ornaments, which could be done at a much easier
rate. The name of the printer, place of his resi-
dence, 850., were either entirely neglected, or put at
the end of the book, not without some pious ejacu-
lation or doxology. The date was also omitted, or
involved in soine circumstantial period, or else

pirinted either at full length, or by numerical letters,
or both together, (as “ one thousand cccc and lxxiiii,”
85c.) but all at the end of the book. There was no
variety of characters, no intermixture of Roman and
Italic, but the pages were continued in a Gothic
letter of the same size throughout. The copies were
few, two or three hundred being considered a large
impression, though upon encouragement received,
they soon increased their numbers.
Copies of these early works are eagerly sought
for by a certain class of book-collectors, and we
occasionally hear of enormous prices being given
for authentic copies of a rare work. The most
extraordinary example of this occurred at the sale of
the Duke of Roxburghe’s library in 1811, when the
object of competition was a copy of the first edition
of [1 De Oameroae 0h‘ Boccacaz'o, printed at Venice by
Christopher Valdarfar in 14:71. It was a unique
copy, and eagerly coveted by many celebrated libra-
ries; but the chief competitors were Earl Spencer
and the Marquis of Blandford, and it was finally
knocked down to the latter for the sum of 2,260l.
The Marquis already possessed a copy of the same
edition, wanting only a few leaves at the end. This
price is of course excessive and exceptional; but
other books sold for large sums, such as several
hundred pounds each. The copy of the Ream/ell of
t/ze History/es 0f Troye presented by Caxton to Eliza-
beth Grey, Queen of Edward IV., was purchased by
Mr. Ridgway for 1,000 guineas.
Such is a brief history of the invention of the art
of printing, which has effected such vast changes in
the political and social condition of men, and which
it is probable will effect changes still greater, and
more momentous. At the time when it pleased
Omnipotent Wisdom to allow this invention to dawn
upon mankind, the feudal system was but slackening
its iron grasp on the lives and fortunes of men, and
a corrupt priesthood still held unlimited sway over
their thoughts and actions. The increasing im-
portance of the towns and trading communities was
rising superior to the feudal castle; the growing
intelligence resulting from the freer intercourse
between people and nations in the exercise of their
peaceful pursuits, now began to call in question the
arrogant authority of an intolerant Church. The
minds of men were preparing for the Reformation,
which the printing of the Holy Scriptures tended so
much to accelerate. The printing-press became the
grand means of communication between the teacher
and the taught, and if the teacher taught falsely, his
book remained open to the censures of all, while the
words of oral instruction might be as fleeting as the
waves of sound which conveyed them to the hearers.
Thus, while the printing-press embalms the thoughts
of the wise, the good and the great, for the benefit
of its own age, and of succeeding ages, it is the duty
of all concerned in its ministration to use their best
endeavours to preserve it as a source of truth, purity,
liberty, and justice. And as this mighty machine is
powerful for good, it may also be made powerful for
evil; so it is the duty of every writer, of every
PBINTIN G.
475
publisher, of every printer, of every compositor, to
preserve it from disseminating falsehood, blasphemy,
and pollution. This is the more necessary now than
at any previous time, because there are more readers;
their number is daily increasing, and the time is
not far distant, when not to be able to read will be
regarded as a mark of degradation by every one who
breathes the air of freedom, and worships God under
the mild toleration of a reformed Church.
SECTION II.—TYPE-FOUNDING.
The art of printing had attained its most valuable
and distinctive form when Gutenberg and his partners
had succeeded in realizing the idea of cast metal types.
There is sufficient evidence that such types were used
by the firm before the secession of Gutenberg, and
although Peter Schoifer may justly claim much of the
merit of practically carrying out the idea, yet the
other two partners must not be forgotten in the award
of praise. Fust was a worker in metals, and must
have been well acquainted with the not inconsiderable
resources of his time in casting and founding. But
there were many difficulties in carrying out Guten-
berg’s original idea of moveable metal types. The
founding of type is one of the most delicate and exact
specimens of casting in metallic moulds that is now
practised; we may, therefore, form some idea of the
great merit of this invention by endeavouring to
realize the time when it did not exist. It is not
possible to do this with anything like completeness,
for inventors are not in the habit of exhibiting or
detailing the successive steps and the innumerable
failures which mark the progress of an invention.
They are satisfied with the successful result, and
even that they endeavour to conceal as long as
possible, in order that they may reap the reward of
their labours. It is, however, very probable that the
first plan was to strike a letter of approved cut,
answering to the modern punch, into soft clay or
plaster, and to pour the metal into the mould thus
P5315800. Names of the various sized types-
Great Primer.
English.
Pica.
6d.
Small Pica.
Long Primer.
Bourgeois.
Brevier.
6% , Minion.
761. N onpareil.
86!. Pearl.
10d, Diamond.

formed; the shaft or body of the letter would then
have to be dressed into shape by hand. This slow
and imperfect method was gradually superseded by
the invention of the highly ingenious metal mould
now in use; but on this point we have no certain
information, for the invention was kept a mystery
for half a century. The printers’ device of Badius
Ascensius, of Paris and Lyons, exhibits a foundry
similar to the modern. The early printers, who did
not cut their own types, do not appear to have had
any difiiculty in procuring letter. Caxton obtained his
types from Ulric Zell, father of the Cologne press;
but when Caxton settled in England he began to cut
type in imitation of the writing common in England
at the period. Wynkyn de Worde supplied many
cotemporary printers with types, of which his black
letter was and is still greatly admired. In 1637, the
art of type-founding was separated from that of
printing by a decree of the Star-Chamber, and four
founders were appointed, who enjoyed the monopoly
of supplying the whole kingdom with type. This
absurd and unjust restriction could not, of course, be
continued for any length of time; but it seems to
have had the effect of erecting the type-founder’s art
into a distinct trade, as it is at present.
The necessity for this distinction will be evident
when we consider how great is the demand for
printing, and consequently for letter, at the present
day. The type founder’s art is also one of great com-
plexity, not only on account of the large number of
sizes of type in common use, but also the large
variety of sorts, or characters, belonging to each size.
There are two kinds of founts which are used
respectively for book-printing and job-printing, the
latter including such work as hand and posting bills,
&c. Book types include eleven or twelve regular
bodies, from Great Primer, which is the largest, to
Diamond, which is the smallest type used for print-
ing books. The following are specimens of book
types :——-
Specimens of the various sized types.
The art of Printing was introduc
The art of Printing Was introduc'ed into
The art of Printing was introduced into England
The art of Printing was introduced into England by
The art of Printing was introduced into England by Willi
The art of Printing was introduced into England by William Cax
The art of Printing was introduced into England by William Caxto
The art of Printing was introduced into England by William Caxton, i
The art of Printing was introduced into England by William Caxton, in 1474: he
The art of Printing was mtroduc ed into England by Wllllam Caxton, m 1474 : he erected 1115 pre
The art of Printing was mtroduc'ed into England by William Caxton, in 1474 : he erected his press
1n a chapel at Westminster.
Great Primer is the largest type used for books; it is used in large Bibles, and is hence called Bible text,
but is now seldom employed. it is double the body of Bourgeois, and about 51% m’s form a foot.1
English is used for Church Bibles, and works in folio and quarto. There are 64 m’s to a foot, and its body
is equal to two Minions.

(1) The letter In being on a perfectly square shank, is taken as the standard of comparison in types, as will be further noticed in
a subsequent section.
e76
PRINTING.
Pica forms the general-standard of measurement inf-casting leads, quotations, cutting rule, and regulating
the price of press works . It is much-used for works of a standard character, such as history, art, &c.
are 71 m’s to a foot, and it is equaleto two Nonpareils. ' '
Small Plea is perhaps the mostgextensively used letter.
two Rubies, and has 83 mjs ‘to aqfoot. .
There
Novels are printed in this body. It is equal to
Larry Primer is much used fori’ivvo‘rks in 12mo., dictionaries, and other works in which much matter is
required to be got 1nto a small" space; ' It'IS equal to two Pearls, and there are 89 m’s to a foot.
Bouryeoz's much resembles Long.‘Pr1me‘r,.-but 1t has 102 m’s to a foot, and is equal to two Diamonds.
It is the type used in the present ;Cyclop'aed'ia.
Breeder, formerly used for printing 6reuz'arz'es, is much used for small works, and for notes. 112% m’s to
the foot.
foot. It is half the size of English.
llflru'ou is used for pocket editions, Prayer-books and Bibles, and also for advertisements. 128 m’s to the
Nouiourez'l, 1453 m’s to the foot: half Pical It is used for the same purposes as Minion.
Pearl, 1.7 8 m’s to the foot; half Long Primer.
Diamond contains 205 m’s to the foot. Rudy is a size between pearl and diamond.
It must be remarked with respect to the above sizes
that, although a skilful printer would be able to name
any size at the sight of merely a single letter of the
fount, and even be able to state what foundry it came
from, and who cut the punch, yet, for want of a
uniform standard, the same named letter will vary
with different founders, and even with the same
founder, so that it is seldom that two founts will
stand together.
Each of the above founts of type consists of five
alphabets, viz, A, A, a, A, a, together with many
other characters, about 200 in all, and these must all
be exactly alike, except in device and widl/z. The
greatest width is for the W and M, and ‘the least for
the and l .
Every one of _ these numerous characters requires
for its formation a puree/2., a malrz'u, a mould, and
type ruefal in the fused state. The punch is a piece
of steel with a single letter at one end. It is formed
by hammering down the hollows and filing up the
edges of. the metal in a softened state. Each letter
must harmonise with all the others in the fount with
regard to height, breadth of stroke whether heavy or
fine. In engraving the letter at the end of the punch,
the artist should aim at an elegant symmetry, and
should not affect an odd or peculiar character, or the
imitation of those antiquated forms which were made
at a time when no better could be produced. This is
one of the great weaknesses of modern designers:
they select some time in the middle ages as the
halcyon period of art, and copy or imitate the bad and
the good, forgetting that the had was the best that
could be produced in its day, and that the artists
would have produced better had they been in posses-
sion of our improved means. The qualities which
the letter engraver should aim at securing are
elegance and sharpness of appearance, combined with
strength and durability.
The matrix is a small piece of copper, two forms
of which are shown in
Figs. 1726, 1727. It is
about Ié-inch long, g-inch
" deep, and wide in propor-
_ tion to the size of the
type: into this the hardened punch is struck. This
must be managed with care, so as to allow the faces
of the‘ types, when composed or set up, to be in a
perfect plane. Hence the depth of the impression in


Fig. 1726.

the matrix is of great im— portance, and it is usual to 5,: f
adjust this depth by filing *7 _,_
down the surface of the copper.
The matrix having thus received a sunken impres-
sion from the raised letter on the punch, all that is
required is to pour a quantity of fluid metal into the
matrix in order to reproduce the letter as it is en-
graven on the punch. But in addition to this the
cast letter will require a support, or body, a, Fig. 1728,
an appropriate width to, and certain
nicks or notches seen below a, which
enable the compositor to place the
letter in the proper position in his
composing-stick without having to
examine every letter by eye.
The measure of the type with
regard to height, width, and body,
is determined by the lype-uzould,
which is somewhat peculiar in its
construction. It is not formed like
the usual forms of square moulds,
Fig. 1729, for it is required in type .
founding that various widths shall
be produced from the same mould;



Fly. 1728.
and it is evident that the mould, Fig. 1729, does not

admit of aready contraction,
for if the piece 12 be slid
upon the‘mould in the direc—
tion of the dotted lines, it 19
would not alter the width of
the type represented by the shaded portion. So
also, if the mould were formed of two parts, as re-
presented in Fig. 17 30,
and one Part were slid ----- ",M
upon another after the ____. // / ’
melted metal had been __________ “
poured into the central Fig. 1730.
square cavity, there would indeed be a contraction
in width, but this would
be ‘attended with a dis- :i----—
tortion in form, as _ 7d ______ __
shown by the shaded
part, out of the mould. Fig-1731-
If, however, the mould were made in two parts, as
represented in Fig. 17 31, it is evident, that by sliding
one part upon the other, the square cavity in the

I:
Fig. 1729.



PRINTING.
4'77
centre, while retaining the same height, would have its
width diminished to any extent required. It is upon
this principle that the type mould (Fig.1732) is
constructed. The two parts (which are of steel,
'\ .



each with a cover of wood on the outside) are so
contrived, that, on being put together, a’ fits into a,
d into d’, e’ into e; 0 falls upon 0’, and the two halves
form in the centre e’ a space or mould in which the
type is formed: the matrix M is placed at the bottom
of the mould, and is retained in its place by the spring
8, and the extent to which the two parts of the mould
slide upon each other is determined by the width of
the matrix. The metal is poured in at the orifice
formed by closing the
upper parts, and the
newly cast letter cannot
be disengaged without
opening the mould: the
letter is removed from
the mould by bringing
' down one of the hooks,
It, to the waste piece
attached to the base of
' the letter.
These details being
understood, a few words
will sulfice to explain
the operation of casting.
The caster stands by the
side of a furnace con-
taining the melting-pot
Fig. 1733. and the fused type-metal,
(the composition of which is given under ANrrMoNr ;
see also ALLOY.) He holds the mould in his left
hand, and taking up a portion of the metal, in a very
small ladle, held in the right, he pours a sufficient
quantity of it into the mould, and immediately jerks
it up for the purpose of expelling the air from the
cavity and driving the metal into the finest strokes of
the matrix. Then, by means of one finger, he releases
the spring, separates the mould, and hooks out the
letter, which has the appearance represented in
Fig. 1734. A good caster will produce 500 letters
an hour of ordinary sized type. The small and the
large sizes require more time: the former, on account
of the increased care, and the latter, to allow the
metal to set.


The types are removed from the caster’s table by
a boy, who, seizing the type by the edges,
breaks or bends an? the superfluous metal at
the bottom with such rapidity, that one boy
will break off from 2,000 to 5,000 in an
hour. He then conveys them to a man seated
at a table, who, with his finger protected by
a piece of tarred leather, rubs the side of
every letter on a slab of gritty stone for the
purpose of removing knobs or globules.
One man can dress from 1,500 to 2,000 let-
ters per hour. The letters are next set up
by a boy, in lines, in a long stick, or shallow
frame, with the faces uppermost and the nicks out-
wards. With the assistance of other frames, a man
called the dresser polishes the types on each edge,
and turning them with the face downwards, planes
the bottom, and forms the groove which brings the
types to the required height, and enables them to
stand steadily; the letters are carefully inspected
with a lens, and the fount being proportioned, i. e.
the proper proportion of each letter, together with
the spaces, quadrats, 850., being counted out, each
letter, &c. is tied up in lines of convenient length for
the printer. Aicomplete fount of pica weighs 8001bs.
For very large types a punch is not used. They
were formerly cast in sand moulds, and hence called
sand-letters; but they are now cast in matrices, which
are made as follows :—The letters having been accu-
rately shaped by means of a rule and compasses on a
piece of copper or brass, are cut out, the back being
left a little wider than the front, the sloping edge
forming the shoulder of the future'type. The piece
of brass is riveted on a smooth surface of brass,
which forms the face of the letter in the casting.
Large types are also formed of wood. Script‘ or
writing-type requires the fine strokes of each letter
to be carefully adjusted, and from their liability to
wear and become battered, this forms an expensive
variety of type.
Attempts have been made of late years to produce
type by means of dies and powerful pressure.‘ We
have seen a machine for making apyro-tg/pe, or type
without heat, which on being turned by hand, pro-
duced type punched out of copper of singular sharp-
ness and beauty. In the Great Exhibition‘ there
were several machines of this kind, one of them
capable of producing 4,000 types in an hour.
1w


Sncridn IIL—Coinrosrxe, IMPOSING AND
_ Connno'rrue.
Supposing a new fount of type to be received at
the printing office, the first operation is to lay it in
the eases, Figs. 1'7 35, 1736, of which there are two,
the upper and the lower case. The upper case
is divided into equal spaces or boxes; the left-hand
division containing capital letters, dotted letters,
figures, fractions, and a few other particular sorts;
the right-hand division containing small capitals, ac-
cented letters, note references, See. In the upper case,
the letters and figures are arranged in their alpha—
betical and numerical order from left to right. In
478 PRINTING.
the lower case, the divisions are unequal ; those, large/st box ; e, d, m, n, h, u, t, i, s, o, a, r, have re-
letters which are most in request having the largest spectively boxes of twice the size of those containing
divisions assigned to them. Thus the letter c has the the letters b, l, v, f, g, y, p, W, and four times the
UPPER CASE.






A B C D E F G A :B c n n r e
H I K L M N O 11 I x L M. N o
P Q R s T v w P Q n S T v w
X Y Z E (E U J x r z 2n as n J
a e 1 0 ii (,3 :B a 6 i 6 1'1 § i
1 2 3 4: 5 6 7 a e i 6 a [[ Jr
a 9 0 t- s s k a a i a j a at a

LOWER CASE. '












._... l: w j (E j j ’ thin spaces ( :3 I s [ \ fl l
& e fil if,
are L fi
fli *3 *3
l m 11 h. 0 y p , W '5 ‘:3
til i g
z q 2
V 11 1) thick spaces a, 1- j _ t M Quadrat‘s
x _ _
Figs. 1735, 1736. Size of Z’ X’ j’ q’ or the crotchets [1 Points, and full- The compositor, standing before the case, Fig.
points, double and treble letters, &c. The letter k 1737, places his copy, i. e. the author’s manuscript,
occupies a spare box in the left-hand division of the ,fiscpmummm'
upper case. The logotypes ff, fl, fi, ffi, and iii, are necessary, because the kerned f cannot be placed 1. close to another f, an i, or an 1. The boxes of letters
most in request are nearest at hand. There is a sepa—
rate pair of cases for the italic letters. .
The proportions in which the letters are supplied
and distributed in the boxes, is as follows :—










.a
Capitals, of each, from 400 to 600.
Small capitals 150 to 300. ‘it;
a, 8,500 f, 2,500 p, 1,700 x, 400 all’;
e, 12,000 g, 1,700 q, 500 y, 2.000 i, 8,000 11, 6,400 r, 6,200 2, 200 f’
0, 8,000 j, 400 s, 8,000 , 4,500 n, 3,400 k, 800 1;, 0,000 , 800 it
b, 1,600 1, 4,000 v, 1,200 : 000 0, 3,000 m, 3,000 w, 2,000 . 2,000
a’ 4,400 n, 8,000 Fig]. 1737.
:The ‘whole fount includes not less than 150,000 on that part of the upper case which is but little used,
letters’ figures: Spaces. 859- and having previously received directions as to spac-
PRINTING.
4.79
ing, 850., he takes in his left-hand a composing-stick,
Fig. 1738, in which he fixes the exact length of the
line by sliding the inner movable portion, and fasten-



Fig. 1738.
ing it by a screw. He next selects a piece of brass
rule, called the setting or composing-rule, of the exact
length of the line, and with a small car or beak pro-
jecting at one end, for lifting it out of the composing-
stick, in which it is placed in order to allow the
letters to slip into their places without any obstruc-
tion from the screw-holes of the stick, or the nicks
in the type. The setting-rule has also another use,
which will be noticed presently. The compositor
being prepared with this simple apparatus, begins work
thus :—-—looking at his copy, and carrying a line or
two in his memory, he takes a capital-letter from the
upper case, and places it in the left angle of the
composing-stick; he selects the remaining letters of
the first word from the lower case, and at the end of
the word inserts a space, which is merely the shank of
a letter without any face, and not so high as a letter
by one-fourth. These spaces serve to mark the
divisions between words, and being below the plane
surface of the type, they receive no ink, and con-
sequently do not appear on the printed page. When
the compositor arrives at the end of a line, and finds
that he cannot get in a whole word, nor even a
syllable of such word, he must nevertheless contrive
to make the words and spaces of the line exactly
fill it without being too tight or too loose, the
reasons for which will be evident hereafter. If
the words and spaces already composed do not
quite fill the line, he takes out some of the spaces
first inserted, and puts thicker ones in instead. Or
if he cannot get in the last word of the line by a
letter or two, he removes some of the thicker spaces,
and inserts thinner ones. He must, however, so
manage his spaces, that the composed matter shall
not appear either too white or too dark. Correct
spacing is one of the tests by which a good com—
.positor is distinguished from an indifferent one. A
good compositor will measure with his eye, as he
proceeds with his work, the exact number of words,
syllables, and spaces which the line requires, and
adjust them accordingly; whereas another man will
have to do his work over again by taking out, fitting
and contriving after the line is composed.
Supposing the compositor to have arrived at the
end of the first line, he takes out the setting-rule,
and puts it in front of the line, which he forces back,
and proceeds to the second line. In this way the
lines are composed, the setting-rule being taken out at
the completion of each line, and put in front of that
line, so as to form the basis for a new one. If the
matter is to be leaded, i. e. if the lines are to be
further apart than the type alone will allow, a flat
ribbon of metal, called a lead, of the exact width

of the page, but only 711th, g-th, or %th as wide as the
type, and not higher than the spaces, is inserted after
the completion of each line, and before the setting-
rule is removed. If the page is to be aae leaded,
two or more leads are placed before each line; but if
tla'a leaded, one lead will suffice. When the work is
double-leaded, or has reglet between the lines, reglet
being of the thickness of the type, the spacing be-
tween the words should be thicker than when the
work is solid, or without leads. There are several
sorts of spaces in the boxes, so that the compositor in
using thick spaces can justify, or make his line fit
properly with thinner and hair spaces. It is also the
compositor’s duty to correct the punctuation of the
author, which is generally both deficient and incorrect.
This he does quite as much by following certain rules,
as by making out the sense of the passage which he
is setting up.
The rapid and apparently eccentric motions of a
compositor at ease, generally excite the surprise of
persons unacquainted with printing, who visit a
printing ofiice for the first time. A compositor may,
however, make a number of rapid motions, and yet
lose time over his work, because they are either ill-
directed, or positively useless. A good compositor
makes no false motions, his fingers aim at one par-
ticular letter, he takes it up by the face end, and if
the nick be not upwards, he turns it upwards in its
progress to the composing-stick; and before it is
actually inserted, his eye ' is directed to the next
letter, which he picks up and conveys to its destina-
tion with as few motions as possible.
When the composing-stick is nearly full—it may
contain 6, 8, 10, or 12 lines, according to the size
of the type—the composed matter is lifted out, and
deposited in a long frame called a galley, Fig.
17 39 ; for which purpose, the setting-rule laid on the
last line allows the whole of the matter in the stick
to be grasped tight
between the fingers _____"
of both hands, the rule preventing it L
from falling to pieces.
This, however, re-
quires skill, for if not properly grasped, the stz'elgfal
of type, as it is called, will fall to pieces, forming
what is technically known as pie. When a con-
siderable quantity of matter has thus been col~
lected in galleys, the compositor proceeds to make
it up into pages, and then into sheets. Taking
the proper number of lines for a page, he adds at
the bottom a line of quadrats, which resemble the
spaces, but are much larger, being 3, 4!, 5, or 6 times
as long as they are broad: be next places on the
top the folio of the page, and the running head, or
line which indicates the title of the work, or the
subject of the chapter, or, still better, of the page,1


"ill
Fig. 1739.

(l) The usual practice of inserting the short title of the book on
every page, or alternate page, is an absurd one, since it reiterates
information which the title supplies, and is not wanted elsewhere.
But as custom and the symmetry of the page require a running
head, it would be very desirable if the author or the cor-rector of
41‘80
PRINTING.
and then adds such leads as are wanted. At the bottom
ofi' the first page he places the sz'yuazfure, or letter of
the’ alphabet, which is intended as a guide in gal/zer-
z'uy,-., foldz'uy, and bz'udz'uy the sheets. [See Boox-
BINDINa] The page thus formed is tied tightly
round with string, or page-cord, as it is called, and
placed on a piece of ‘coarse paper. Having made up
as many pages as the ‘sheet consists of,—-A for folio,
8 for quarto, 16 for octavo, &c.,—-he places them upon
a large slab of marble let into a frame, and called
the rarraposz'uy-szfoue. The pages are of course imposed
OIlLII-Ile stone in an order the reverse of that in which
they: appear in the printed sheet, the first page on the
right-hand being at the extreme left in the type, and
set on. When the pages are properly placed, the
compositor takes an iron frame called a clause, which
is. divided by cross-bars into compartments, the inner
angl‘es of which are carefully squared, and places it
overvthe pages, and adjusts between them a number
of pieces of wood or metal called furniture. Within
the: chase, next to the pages, he places other pieces
of ' iron, called side and fool-slides, which are rather
wider at one end than at the other, and between
these and the chase he drives in small pieces of
wood, named guoz'us, which decrease in width in the
same proportion as the side-sticks. By means of
a mallet and a slzoolz'uy-slz'c/e (which is a piece of
wood' 1 foot long, 15 inch wide, and half an inch thick),
he“ dri ves the quoins towards the thicker ends of the
side: and foot-sticks, and the quoins thus act as
gradual and powerful wedges, forcing the separate
pieces of type into a compact body, so that all the sides


the average width of the letters is half their depth, or
half the width of the letter in. Hence the number of
m’s in the length of the page multiplied by twice the
number of m’s in the width, and this product by the
number of pages in a sheet, gives the average number

_,EE,_=_._.__ .


Fig. 1740.
cii‘ipf' the pages being many times loelred up, the whole
' ‘mass of many thousand letters may be lifted off the
stone. This united mass is called a form, the one
containing the first page is the outer, and the other
the; inner form. [See Booxnuvnrne] The two
forms of an octavo sheet are shown in Fig. 174:0.
'Illie compositor is paid at a certain rate for every
thousand letters composed. The letters are not ac-
tually counted, but they are estimated by assuming
as. the standard the letter 1n, on account of its being
on': a 'perfectly square shank; then supposing the page
to: be solid or unleaded, it is ascertained how many
m’saof the particular fount the page is long, including
the-running-head at the top and the white-line at the
bottom. The width of the page is next found, or how
many times the letter m would be repeated in a line
of given length. But as nearly all the other letters
are“. of much smaller width than the letter m, the
number of m’s in a line fails to represent the average
quantity; now it has been found by experience that
the press made the running head an index to the page to which
it refers. This is done in the present work, where of course it is
easy of accomplishment by the compositor himself. In the
Editor’s work on ‘-‘ Rudimentary Mechanics,” this plan has been
carefully carried out, and it is also done in an amusing and elabo-
rate'manner in Mr. Thackeray’s Novel of “ Esmond.” The chief
reason why this useful and sensible plan is not generally adopted
is, that the'varied running head requires to be inserted in the
proof-sheet after it is made up by the printer, and is consequently
charged ‘for as a correction. Whereas if the short title of the work
be repfiiated 011 every page, the compositor inserts it in the making-
up, and it is not charged for extra.
of letters per sheet. For example, in easz‘z'ry up, as it
is called, a sheet of octavo in pica, suppose it be 4L6
m’s long and 22 m’s wide: then 416 X (22 X 2) X 16
(the number of pages in an octavo sheet) :: 82,384.
In such case the compositor would be paid for 82,000
letters, the odd hundreds, 850. being omitted unless
they exceed 500, which are paid for as 1000. If the
sheet be in solid type of the ordinary size the compo—
sitor’s price in London is 6d. per 1000. The prices
for the other types are given with the specimens in
Section II. If the type be leaded the price is id.
per 1000 less: if the work be composed from a
printed copy, the price is i—d. per 1000 less, (MS.
copy, and especially the MS. copy of some authors,
being difficult to read, and consequently consuming
more time than printed copy.) Some kinds of work,
such as tables of figures, which form a dense mass of
type, are paid double. Works in a foreign language
are paid ed. per 1000 more in type of the ordinary
size, and 3d. per 1000 more in smaller type. For
Greek, with leads and without accents, 85d. per 1000
is paid; without leads or accents, Sid; and with
accents, 10%d. Hebrew, Arabic, &c., are paid double.
The rate per thousand paid to the compositor includes
not only the composing, but the making-up into pages,
imposing, correcting any errors which he may have
committed; and when the impression has been worked
off, and the type is returned to him, he has to distri-
oule the letters into the various boxes of his cases
before such type can be again used for setting up fresh
matter. Holding a quantity of the composed type in
his left hand, with the face towards him, the compo-
sitor takes up one or two words between the fore-
finger and thumb of the right-hand, and drops the
letters each into its proper box with great rapidity.
A good compositor will distribute 50,000 letters in
a day. Distribution occupies one-fourth of the compo-
sitor’s time ; making—up, imposing, and correcting,
another fourth; so that he has only one-half of his
time for that labour which forms the sole datum for
PRINTING.
4181
estimating his remuneration. In order to earn a fair
week’s wages he ought to be able, while composing,
to ‘pick up at the rate of 2000 letters per hour, which
is at the rate of 241,000 letters per day of 12 hours,
and 14141,000 per/week. In picking up each letter the
hand has to traverse at least 6 inches on an average
and back, and this exertion long continued in ‘a stand-
ing posture (which is necessary for freedom of action)
becomes extremely laborious. When it is also con-
sidered that the air of the printing-office is generally
of the worst description, contaminated as it is by the
fumes of printers’ ink, grease and moisture from the
steam-presses in the basement; vitiated by the respira-
tion of several hundred human beings, and by the com-
bustion of numerous gas-lights ; considering, too, that
some of the largest printing-offices are in the most
crowded parts of the metropolis,—we have altogether
as large a collection of noxious influences as may ge-
nerally be found to concur in a factory in destroying
the health of the persons who spend so large a portion
of their lives within its walls. Our experience extends
to a considerable number of the large London printing-
olfices; and we are sorry to have to state, that scarcely
in any one that we are acquainted with, has any
attempt been made to diminish that monster evil-—
bad air—by an efficient system of ventilation. If
ordinary means were taken to let out the foul air and
provide proper openings for the admission of the fresh,
many of the objections to which we refer would be
mitigated or removed; the men would improve in
health and longevity; and the master would have the
satisfaction of knowing that he had done his duty to
those persons, who, while they serve him, are at the
same time committed to his charge, and he is to a cer-
tain extent morally responsible for their welfare. We
have no reason to hope that these observations will
produce any useful result; but it is nevertheless our
duty to make them, and to state distinctly that, next
to intemperance, nothing is more destructive to health
than the respiration of vitiated or contaminated air.
When the two forms of the sheet are removed from
the imposing-stone they are conveyed to a hand-press,
and a proof of the sheet is pulled. This proof is taken
to the first reader or correcior (f the press, who folds
the sheet, examines the signatures, the folios, and the
running-heads ; sees that the pages have been properly
imposed, that the chapters are correctly numbered,
&c. He then compares the sheet with the author’s
copy, sees that underlined words are set up in italics,
that the proper capitals are used, and that the work
is done in a workmanlike manner. He then calls the
reading-bop, who reads the copy aloud as rapidly as
' words can well be uttered, without much attention to
the sense. The first reader being himself a practical
compositor, his experienced eye enables him to detect
every trifling error, such as would pass quite unnoticed
by a person not in the trade; as, for example, whether
a letter from a wrong fount had got into the fount
used by the compositor; such a mistake is corrected
in the proof by drawing the pen through the wrong
. letter, and writing 20f for “ wrong form ” opposite to
it in thenmargin. Other mistakes are also pointed
VOL. II.

out by appropriate marks ; and having gone through
the sheet, he writes upon the author’s copy, at the
exact word, the commencement, signature, and folio,
of the succeeding sheet, together with the figure for
the next wood-engraving, if the work be illustrated
by numbered woodcuts. He then returns the sheet
by the reading-boy to the compositors, who first ex_
amine the corrections, and gather up from their cases
the words, letters, and corrections marked in the
margin, and proceed to the imposing-stones, to which
the forms are now returned, and unlocking them, they
lift up with a blunt bodkin each line requiring cor-
rection, draw out the wrong letter, or word, and insert
the right one, at the same time adjusting the spaces
so as to allow for the increased or diminished fulness
of the line. Should a word or several words have
been carelessly omitted, or a word be inserted twice
over, it may be necessary to overrun a large number
of lines to the end of the paragraph, to make room for
the insertion or to adjust the spacing. Should a sen-
tence have been omitted, its proper insertion may
require the overrunning of pages instead of lines. All
this consumes a good deal of time, and indeed the
overrunning is generally reckoned as equal to half the
composing; that is, it takes half the time to overrun
that is occupied in setting up the type in the first in-
stance. The errors being corrected, (and sometimes
new errors introduced in the process, the eradication
of which requires much subsequent care,) another
proof is pulled, which, with the original proof, is
transferred to the first reader, who compares one
with the other to ‘see that his marks have been pro-
perly attended to: if not, he returns the proof to the
compositors. But if he is satisfied, the clean proof
is sent to the second reader, who subjects it to an
intellectual as well as technical revision; it is read
once more against the copy, further corrections are
made, and defects in the author’s style and meaning
are queried. There are few literary men who would
not admit the value of the services thus rendered by
the second reader; and the Editor takes this oppor-
tunity of expressing his grateful thanks to those gen-
tlemen who for many years past have read his proofs,
and assisted him in making his meaning clear. The
technical corrections in the second proof being made,
a clean proof is pulled for the author; queries are
inserted in ink, and this proof, together with the
copy, is sent to the author.
Notwithstanding the care that has been bestowed
upon the proof, the author sometimes finds his writing
to have been misread and consequently his meaning
strangely misinterpreted. Sometimes, however, the
blunders in the proof escape even the author’s parental
eye, and regarding the proof of his work with the fond
partiality of a parent, he has a keen appreciation of all
the beauties, but is positively blind to the faults and
defects of his work. Caleb Whiteford has published
an amusing collection of “Mistakes of the Press.”
D’Israeli, also, in his “ Curiosities of Literature,” has
given a list of some of the more celebrated errors
which have passed through large editions of well-
known works, and have even caused such works to be
r I
4482
PRINTING.
sought out by book collectors, and valued for their
very blunders. Thus the “Vinegar Bible,” as it is
called, is a curiosity in its way on account of the
“Parable of the vineyard” being made the “Parable
of the vinegar.” There are many other such books.
Some of the most curious blunders, however, occur
in authors’ proofs. For example, in the editor’s
“ Student’s Manual of Natural Philosophy,” pub-
lished in 1838, in the chapter on “ The Telescope,” at
p. 4191, the following passage occurs as it was written
—-“ the light received from any luminous body is not
to be considered as a whole, and coming from the
entire surface, but as a part, and made up of a great
number of bundles of rays—one bundle proceeding
from every distinct point of the luminous body.”
When the author received his proof the word marked
in italics was printed rags. In the present Cyclopaedia
some remarkable blunders have also occurred in the
author’s proofs. For example, in the article IRON the
following passage, as written by the editor, ran
thus z—“ln the moulds left by the decomposition
of shells and madrepores, the shapes of which are
assumed by the minera,” &c., the word in italics
was printed mad-refines. In the article LEAD it is
stated that “protoxide of lead melts at a red heat,
and in this state attacks silica wit/z ease, pene-
trating an earthen crucible in a few minutes.” In
the proof the words wit/z ease were printed with rage.
In a reference from OBLIQUE—ARCH to SKEW-BRIDGE
the proof had “ See KEw-BRIDGE.” Errors of this
kind show how necessary it is for the author or editor
to be careful and watchful in reading his proofs, and
comparing the .revises with the corrected proofs.
Some of the early printers justly prided themselves
on the correctness of the editions which they issued.
Thus Aldus (the inventor of the Italic and the im-
prover of the Roman letter, who established a printing-
office at Venice in M96) considered it his chief duty
to correct every sheet; and so busy was he with this
employment and the multifarious business of his
ofiice, that he declared in one of his letters that he
could scarcely take food or strengthen his stomach
owing to the multiplicity and pressure of business;
“ meanwhile, with both hands occupied, and sur-
rounded by pressmen clamorous for work, there is
scarcely time even to blow one’s nose.” His son and
grandson sustained his reputation, and the Aldine
editions are much prized for their accuracy. One
remarkable feature in these editions is the absence of
points and stops in the title-page, a peculiarity which
is imitated in the so-called Aldine editions of the
poets published a few years ago.
When the author has corrected his proof, and
returned it to the printer, the author’s corrections
are made, and charged for extra; and as the extent
of these corrections depends upon the author, and
vary in every page, the charge for the same is subject
to considerable variations. This is one of the most
unsatisfactory parts of printing, and often brings the
author, the printer, and publisher into disagreeable
collision. If the author’s corrections are numerous,
a second author’s proof, called a revise, is sent to

him; and if the author be a gentleman of uncertain
temperor careless mind, or should happen to be
unusually critical while reading his proof or revise,
he may introduce such extensive insertions and cor-
rections, as to make the cost for correction equal or
even exceed that for composing. When, however,
the author is satisfied with the first, second, third,
85c. revise, he marks it “For Press,” with the date,
and returns it to the printer. The “Press Proof,”
as it is called, is once more read with a view to weed
out any remaining technical errors, to correct the
spacing, to take out defective letters, 850.; and at
length, all corrections being made, the printer marks
on the proof the number of copies to be printed, and
sends it to the press-room.
There are various other details respecting the
management of proofs, which are of too technical a
character to be of interest to the general reader.
These are better learned from experience than from
books, and are moreover exceptions to the general
practice such as we have described it.
SECTION IV.—Tnn PRINTING-PRESS.
The earliest form of printing-press was nothing
more than an ordinary screw-press, with a contrivance
for running the inked form of types under the screw.
With such a press, printing was a slow and laborious
operation: the screw was brought down upon the
form with a dead pull, to the great danger of injuring
the faces of the letters. This press was greatly
improved by Willem Jansen Blaew, a mathematical
instrument-maker of Amsterdam. He printed many
books and maps constructed from the observations
of Tycho Brahe, who for many years employed him
as an assistant, and for making his instruments.
Blaew’s press continued in general use up to the
beginning of the present century. It is represented


Fig. 1741.
COMMON PRINTING-PRESS.
in Fig. 174:1, in which UU are two checks or up-
rights, bound together by a horizontal bars, the first
of which a is called the cap ; the second, or the izead

PRINTING.-
Q83
A, is fitted by tenons at the ends into mortices
between the cheeks. The head i is suspended from
the cape by ‘2 screw-bolts ss, and in the centre of
it is fixed by 2 short bolts a brass nut containing
a hollow screw or worm for receiving the upper
end of the great vertical spindle or screw s, by
which the pressure is produced. The third bar
t’, called the slielf or till, is intended to guide and
keep steady a part called the dose k’, which contains
the spindle and screw. The next cross-bar it, called
the winter, is for supporting the carriage. The
spindle and screw .9’ is a ‘strong vertical bar of iron
terminated at the lower end with steel: its upper
end is formed into a small screw, which works in the
small brass nut of the head; and in the eye of the
spindle, just below the upper extremity, is fixed the
handle n, by which the press is worked. Under the
spindle is the platten p, which imparts the pressure
to the paper. It is suspended from the point of the
spindle by the hose ii’, a square frame or block of
wood which passes through the ‘shelves. The lower
end of the spindle passes through the hose, and rests
by its point in a plug fixed in a brass 'cup supplied
with oil, which is again fixed to an iron plate let into
the top of the platten. When the pressman pulls
the handle H, he turns the spindle, the round of
which moves in its screw box, and by its descent
brings down the platten, which thus presses on the
paper lying on the form of type. The platten is sus-
pended from the spindle, and rises up again with it by
means of a garter or fillet of iron screwed to the hose,
and entering into a groove round the upper end of the
spindle. The platten is hung truly level by 41 threads
passing from its a corners to the 4: corners of the
lower part of the hose. The form of type F, is con-
veyed under the platten by means of a carriage 0 e,
which ‘is supported on a horizontal wooden frame, the
fore part being sustained by a forestay, while the back
part rests on the winter. Below the plank of the
carriage are short pieces of iron and steel, cramp-
irons, which slide upon two long iron bars or ribs
fixed on the upper part of the horizontal wooden
frame. In .order to run the carriage in and out upon
the wooden frame, there is placed below the carriage
the split or small spindle with a double wheel on the
middle of it, round which are fastened leather belts,
the opposite ends of the belt being nailed to each
end of the plank of the carriage. On one of the
ends of the split is fixed the winch or handle 20', by
turning which the carriage can be run in and out
below the platten. The carriage is a strong wooden
plank, on which is fixed a square wooden frame
forming the cell, in which is placed a polished stone
for sustaining the form of types. To this cell are
fixed stay-belts of leather, one end attached to the
cell, and the other to the checks of the press, so as
to prevent the carriage from running out too far
when drawn from under the platten. On the outer
end of the plank is fixed the gallows, g, for supporting
the tympans when they are turned up to receive a
new sheet of paper after each impression. These
tympans r’ are light square frames, covered with parch-

ment. They are formed of 3 slips of thin wood,
with a lieadbarid or top slip of thin iron. The two
tym pans are so constructed, that the one represented
as the upper one in the cut, shall lie within the
exterior one, to which it is fitted by ironv hinges to
the cell. Between the two tympans are placed 2 or
3 folds of blanket, for the purpose equalizing the
pressure of the platten upon the surface of the types.
A square frame of thin iron, called the frisket, t t, is
attached by hinges to the headband of the exterior
tympan, and is made to fall down upon the tympan,
so as to enclose the ‘sheet of paper which ist'o be
printed between them. The tympan and frisket
being thus folded down, lie flat on the form of types,
and the carriage containing them is run beneath the
platten, so that when the handle H is pulled, the
platten presses upon one-half of the form of types:
the carriage is then run further in with the other
half of the form, and in this way, by means of two
separate pulls, the impression of the types is made
upon the paper. By turning the winch iv", the
carriage is withdrawn from beneath the platten, and
the tympan, on being lifted up round its hinges, rests
obliquely against the gallows. The frisket is then
lifted up on its hinges, and supported by a slip of
wood descending ‘from the ceiling, and the printed
sheet is taken out, and a clean one put in. Every
time the carriage is run out, the type is inked by
means of two bulky inking-balls, consisting of two
circular pieces of pelt, leather, or canvass covered
with composition, stuffed with wool, and nailed to
wooden stocks. One of these balls b is represented
in the tall-male, and the other 6' on the ball-eloe/e,
which contains the ink heaped up in the angle, but
brought gradually down to a thin layer in front of
the block.
About the commencement of the present century
several defects in Blaew’s press were remedied, as in
the .djJOllO press, invented in France; Prosserz’s press,
Rowortli’s press, but especially in the Slaaliope press,
which we now proceed to describe. In Fig. 17 4:7,
13 :B, the body of the press, is a cast-iron frame in one
piece, firmly screwed down to a wooden cross w’.
Two horizontal rails n are screwed at p 1), Fig.1 M8, to
two projecting pieces cast in one piece with the body
for sustaining the carriage when the pull is made.
The ribs of the carriage slide in grooves in the upper
surface of these rails, and are moved by the handle 10
with a split and leather, as in the common press.
A brass nut or hollow screw is fixed in the upper
part s of the body of the press, in which the upper
end of the spindle works. The mode of giving the
descending motion to the screw is the chief improve-
ment in this press. This is shown separately in
Pig. 1742; while in Figs. 1743, 17 4:41, are represented
the screw with a section of the internal screw into
which it fits. This screw is attached above s,Fig.1'Z417,
to the rim LL, while the toe C of the screw fits into
the cup 0, Fig.174i5, and the piece containing the cup is
screwed by the holes Hz to the platten P, Fig. 17416. The
handle H, for working the press, is firmly fixed into the
low er end of the vertical bar 6, the lower point of which
112
4841
PRINTING. ~
moves in a hole in the main frame, while the upper
end passes through a collar in a projecting piece H :
being passed through this collar the end of the bar
joins‘ a short lever
L, which is again
connected-by the
link Z with another
short lever L' fixed
on the upper end
of the screw. The
pressman, in pull;
ing the handle H,
turns round the
spindle s, and by
its connexion with
the rod 0, &c., the


Fig. 1742.
great lever turns with it, and causes the platten to
descend and produce the requisite pressure. The
power of the lever H is transmitted to the screw in
such a way as to produce certain re-
quired effects at different parts of
the pull. At the beginning of the
pull, when motion only is wanted,
the handle H. lies in a direction
parallel to the frame across the
press; and the short lever L’, which
is nearly perpendicular to it, is like-
wise perpendicular to the connect-
ing rod Z: but the lever L Of the


7
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r
n‘
/W‘“\
“nun! ,
I
l
A I,‘
'l
\k


dig; v
\\\


Fig.174-1».
screw makes a considerable angle with Z, and it then
acts by a spindle radius to turn the screw: when,
therefore, the lever H begins to pull, the lever L’ acts
with its full power upon
another shorter length of
lever on L, so that the
screw will be turned
more rapidly than if the
link Z were attached to
it: the pull being con-
tinued, the position of
the lever changes, the
_ length of L always in-
creasing from. its coming
nearer the perpendicular
to Zan-d the acting length


_ of L’ diminishing, since by the obliquity of the lever
the link’ approaches the centre. The handle H is
now brought into a more favourable position for

‘ the pull,‘ as ‘the -'pressman finally pulls in a direction
nearlyv at right‘ angles to its length; by‘ which means
the platten‘ is‘at'first brought quickly down upon the
paper where ‘motion only is required; but as the levers
are gradually coming into the most favourable position






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it v ;
l ’ ,
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Fig). 174a "
for exerting the greatest force, this maximum pres-
sure is produced just when it is wanted, that is, when
the platten touches the paper to be printed. The
range of the handle is limited by a stop, which is
movable to a small extent in order to vary the pres-
sure for different kinds of work. The insertion
of the lever, by which the power is applied, into the
arbor, and not into the spindle, leads to several ad-
vantages: 1. The length of the lever is equal to the
whole width of the press instead of half, and is also
in a better position for applying the man’s strength.
2. There is the'additional lever of the arbor head;
3. the additional lever of the spindle head; and
lastly, the screw itself may be so enlarged in diameter
as greatly to increase the power. The platten, which
is screwed to the under surface of the piston, is of
considerable weight, and the man would have to
waste much strength in raising it from the form after
the impression was made, were it not for a balance-
weight W suspended upon a lever and hook at the
back of the press, which counterbalances the weight
of the platten, raises it from the form, and brings the
bar-handle Hb'ack again readyfor anotherpull. . The
form of types, 1‘, instead of resting on a stone, as in
the ‘old press, lies upon a cast-iron block, with a per-
fectly fiat horizontal surface, and the size of the press
is such that a whole sheet can be printed at one pull.
A variation in power is also obtained by a screw
adjustment at the end of the link Z, by which it can
be shortened. This is done by fixing the centre pin,
which unites it to the lever L, in a bearing place, and
slides in a groove formed on the. side regulated by the
screw. In this way the descent of the platten may
be increased or diminished, and its surface is turned
so as to be perfectly plane. Various other improve-
ments in this press have been patented. In one case
the screw is got rid of by 'a spiral or curved inclined
plane fixed on the head of .the press. On the upper
end of the spindle a cross arm is placed, which acts
against a fixed inclined plane, and thus acts the part
of the screw: the acting faces are made of hardened
steel. In Mr. Keir’s arrangement the slider s is
formed by boring out a cylindrical hole down the
centre of the press, and fitting accurately into the
cylinder, to the lower end of which is fastened the
platten: a flat side is made to the cylinder, which is
PRINTING.
-' 4185
prevented from turning round by'abar'of iron screwed been‘ improved. ‘In the lower end of the spindle a
across the two cheeks and bearing against the flat
side of the cylinder. The lever apparatus has also
L’
JAR, % n
L»








a .
‘ ti, i
‘all
or ‘ gill r
' -¥; ..
| flzii l
i'.
-_ l -.! ‘

________-__:
.Fz'g. 1747.
of the great screw in the same time, and the connect-
ing rod Z, Fig. 1747, is thus made to pull in a hori-
zontal plane, while in the old construction one end
remains level when the other descends, which occa-
sions an unequal wearing of the joints. In the
simple and eflicient arrangement shown in Fig. 1749,



Fig. 1749.
the screw is also got rid of by means of a cam or
wedge c, which fits into a cup 0”, and is hollowed out
above for the reception of the projection 0’ attached to
a piece which is connected by an arm and a coupling-
bar 6, with the handle Iz. . This piece is suspended by
the main bolt m from the fixed bearings of the frame.
In the position shown in the left-hand figure the
platten p is raised, but the pressman, by pulling the
handle towards him, brings the swinging piece and
the wedge into the vertical, the effect of which is


\
it!
' it,‘
THE STANHOPE PRESS.
screw is cut and fitted into a nut; the spindle is made
to rise and fall through a space equal to the descent
‘5* Q






,1
w

1,1 It. __~_.:w;~r-..- . r
l ' ' J



Fig. 1748.
to send down the platten with great but regulated
force, and with a very moderate expenditure of
power on the part of the pressman. The range of
the press may be adjusted by means of the power-
screw 12. -
The press, such as we have described it, is worked
by two men, one of whom inks the type and attends
to the impression; the other works the press.‘ Sup-
posing the two forms to be correct, the inner form is
first laid on the table, and‘ secured in the centre by
means of quoins. A sheet of stout paper is pasted
on the frisket frame, and also secured upon the
tympan. The form being inked an impression is
taken on the frisket, after which the whole of the
printed part is cut away, the portion which is left
being intended to protect the paper from being
soiled. ' A sheet of paper is next folded according to
the crosses of the chase, and being placed on the form
it is carefully opened so as to lie ‘evenly on the form
with the same margin as it is to have in the working.
The tympan being wetted is closed down on the form
and an impression taken, when the paper adheres to
the tympan, and forms a guide for laying on the
subsequent sheets with are to be printed. The
points are next selected; these are pointed wires
fixed in the tympan; they perforate the sheet and
thus serve as guide marks to the pressman. The
tympan frame is screwed on so that the points may
fall into the cross of the chase. The paper is now
brought from the wetting room, where it has been
damped by passing it 7% or gth of a ream at a
time, through water, and allowing it to soak 2 or
3 days until it is evenly damped throughout. A
486
PRINTING. ,
ream of the paper is now laid on the horse, which is
an inclined plane, placed on the left end of a long
deal table, called the cam/v, and as the paper is
worked, it is brought from the tympan to the bank
The bank and horse are placed at the right front of
the press. The paper being supplied, the man takes
a sheet and lays it carefully over the tympan sheet,
closes the frisket over it, shuts down the tympan and
frisket upon the form, previously inked, runs the
table under the platten, pulls the handle of the lever
with his full weight until it is brought down by the
stop; the platten thus descends and produces the im-
pression. Then gradually releasing his hand, the ba-
lance weight raises the platten, the bar returns to its
first position, the table is run out, the tympan and
frisket raised, and the frisket thrown up. The sheet is
now taken off the points and examined to see whether
the impression be good. The first impression is gene-
rally very defective; the parchment lining of the
tympan may be thicker in some parts than in others,
the blanket may be worn, or the types not quite equal
in height.‘ The men therefore proceed to overlay ,' that
is, they paste on the tympan pieces of paper of the
exact size of the defects, thin or thick, as may be
required. If any part of the impression he too strong
a portion of the tympan sheet is rubbed or cut away.
Another impression is then taken, and if the men are
satisfied with it, it is submitted to the overseer, who
gives orders to proceed. One of the two pressmen,
as already stated, inks the type and examines the
impression from time to time, to see that it is of the
proper colour, and that no imperfections appear in the
work. When the required number of impressions of
the inner form is worked off, the form is removed,
washed with lye, sent to the composing room, where
it is again ‘washed, rinsed and distributed. The
pressmen then lay on the outer form 'with as much
care as the inner, and having obtained a satisfactory
impression they proceed to perfect, that is, to complete
the sheets by printing on the white sides. In this
operation the points insure what is called perfect
register, whereby the pages and lines fall exactly on
the back of each other, as may be seen by holding up
to the light a page of any well-printed book. Hence
in perfecting a sheet by printing on the other side,
the points are made to pass through the same holes.
When the impression of the outer form is brought
up, a thin sheet of white paper, called the set-017 s/zeel,‘
is placed over the tympan sheet, and on the points;
the object of this sheet, which is frequently changed,
being to keep the impression clean; for as the damp
print of the side already printed impresses itself on
the set-off sheet, ‘and this again on the next sheet
that is put on to be perfected, it is evidently of im-
portance to change this sheet often.
The‘ pressmen are paid by the lolceii of 250 im-
pressions. Supposing the number required of the work
to be printed be 500, and the price for working the
sheet be lit-cl. per token, each man receives 9d. per
sheet for 500 impressions of_ each form. The price,
however, varies with the size of the type and of the
form, with the quality of the paper and of the ink,

with the number of impressions and the amount of
care required. Common work pays deal. per token,
yoocl work 603., superior 7%, very oesi 8d, Qrl, and 12d.
per token. Two good pressmen will complete 1 token
or 250 per hour, but this varies greatly with the kind
of work. For very fine work and with wood engrav-
ings the men may be limited to 50 impressions per
hour, in which case they are paid by the 'week. The
woodcuts are imposed in the chase and locked up on
the table of the press. They are worked in the same
manner as type, but require more care. In fine print-
ing with woodcuts the tympan is of silk, cambric or
fine broad cloth.
The ink is distributed by means of balls or
rollers. The man with a ball in each hand dabs
them upon a thin layer of ink in the fore part of the
inking-block, and then against each other, so as to
distribute the ink regularly over them. The moment
the tympans are lifted up, he begins to beat the
type at the right-hand near corner, and goes up that
side of the form, and returns, and leaves off at the
left-hand near corner, taking care to make the form
feel the force of the balls by beating hard and
close. In the operation of heating, the balls should
be constantly turning round in the hands, as it keeps
them in their proper shape, and thereby renders them
more safe and pleasant to work with.1 A corner not
touched by the ball, prints pale in the next pull, and
is technically called a friar; a spot containing too
much ink, and consequently printing too black, is
called a monk.
The roller, Fig. 1750, is a wooden cylinder with a



thick coating of composition of glue and treacle :
through the middle of the cylinder passes an iron rod
attached to a curved bar passing over the roller and
furnished with two handles. The roller revolves
freelyf'on the rod. The inking table stands to the left
of the‘fjii‘ess. It is of mahogany or of iron, about 4'!
feet high and 3 feet 4: inches wide. At the back is
a slightly elevated stage with a recess at each end, in
one of which is the ink, and in the other the muller
by which the ink is spread out in a thin layer in front
of the stage. Some tables are furnished with a dis-
tributing roller which runs the whole length of the
table, and on turning this roller it presents a line of
ink to the inking roller. See Fig. 1751, in which the
distributing-roller and the trough are also shown de-
tached. The trough of ink is pressed up to the dis-
tributing-roller by means of balance-weights. The
man takes up a portion of ink, and distributes it care-
fully on the table until the whole face of the roller

(1) Stower’s Printer’s Grammar, 1808. This work, which is
dedicated to Earl Stanhope, contains a minute description of the
Stanhope press.
l’RlNTIN G.
4.87
is evenly covered: he then rolls the form with an
equal, light and
steady motion,
varying his force
‘with the size of
the type and
other circum-
stances.
The ink used
by the early
printers was
black enriched
with a dark blue
or purple tint.
It was very
durable, and still
offers a reproachful' contrast to the brown and faded
inks of more modern times. Not that the art of
making good ink is lost, but that the great demand
for cheap ink leads to the employment of inferior
and badly-prepared materials. It will be seen by
referring to our article INK, that printer’s ink differs
essentially from writing-ink, the former ‘being an
oily, and the latter a gummy compound. The black
colour is due to lamp-black, the finest quality of
which should be used, and the oil, nut or linseed,
should be boiled, and burned into a varnish. The
ingredients should be well mixed, and ground until
quite impalpable, or the ink will clog the types and
the inking apparatus, and tear the face of the paper.
It should not be liable to dry when left in masses,
but should dry quickly in thin layers. Turpentine
is added to promote the drying. The drying of the
printed sheets must not, however, be hurried, other-
wise a skin will form on the surface of the letters,
and prevent the under part from drying; and the
consequence is, that when the sheets are pressed,
rolled, or beaten for binding, the filmy skin breaks,
and the ink spreads, and sets off on the opposite
pages.
Ink-making constitutes a distinct branch of manu-
facture, and although no printers manufacture it, yet
some of them add ingredients to it, which are sup-
posed to improve its quality. Printer’s ink is an
expensive article: the commonest book-ink costs
from 18. to ls. 6d. per lb. ; but the usual quality is
28. 6d, 3.9., and 4a., and for superior work 58. and 68.;
for fine wood engravings, we have heard of 10s. per lb.
being paid for it, but this is unnecessarily high.
Among the various recipes given for the manu-
facture of printer’s ink, we select the following :—
Fine old linseed oil boiled to a thick varnish, and
cooled in small quantities, 3 gallons. A small quan-
tity of black or amber rosin may be dissolved in it,
and the mixture is to stand for some moments to
deposit impurities: then mix with the finest lamp-
black, and grind carefully for use. Indigo or Prussian
blue may be added to improve the colour; but either
of these pigments will be found to clog the ink.
Turpentine is added to improve the drying quality.
Some makers are of opinion that no ink can be
depended on of which oil is the basis. Balsam


copaiva has been substituted. Of this, take 9 oz., of
the best lamp-black 3 oz., Prussian blue 1% oz.,
Indian red 71% oz., turpentine, soap, dried, 3 oz. This
is said to produce a fine colour, but not to work
clear.
When the sheets are worked off, they are hung up
in the warehouse to dry by means of a
wooden peel, Fig. 1752. After a day or
two, they are taken down, and laid in heaps,



Fig. 1752.

or arranged for gathering, each signature
by itself, as explained under BOOKBINDING.
For the finer description of works, the sheets are hot
or cold-pressed.
Sncrron V.-—THE PRINTING Macnrnn.
The printing press described in the last section
was for along period capable of supplying the demand
for books and newspapers; but the important political
events which occurred at the close of the last century
created a demand for newspapers which the ordinary
press could not supply. About the same period the
general diffusion of education produced a greatly
increased demand for books; while the improvements
in roads and conveyances facilitated the means of
distribution both of newspapers and books. The
ordinary produce of the printing press was 250 single
impressions, or 125 perfected sheets, per hour. It is
true that a larger number was produced in newspaper
OfilCBS, either by excessive labour or by means of
duplicate presses and forms of type, but the produc-
tion of copies was quite inadequate to the demand.
About the year 1790 Mr. William Nicholson, a
gentleman connected with periodical literature, took
out a patent‘ for a printing machine in which the
type was fixed upon a cylinder which revolved in
gear with another cylinder covered with soft leather;
an inking apparatus being applied to the type, the
paper was printed by being passed between the two
cylinders. This plan does not appear to have been
put into practice. The next inventor was Mr. Konig,
a German, to whom belongs the merit of the inven-
tion of the first steam printing machine. His plan
differed from Nicholson’s; the type was laid upon a
flat surface, and the impression given by passing it
under a cylinder of large size containing the paper to
be printed. This is the leading idea in the subsequent
machines. Konig in his first machine printed on one
side only, but he afterwards contrived one for print-
ing on both sides before it left the machine. Konig
attempted first to get his machine into use on the
Continent, but not meeting with any encouragement
he proceeded to London about 18041, and submitted
his scheme to several printers. After many disap-
pointments and much of the heart-sickness of hope
deferred, which the needy inventors of novelties are
so well acquainted with, he at length made an arrange-
ment with Mr. Bensley, sen. Their first exertions
were directed to the acceleration of the speed of the
488
PRINTING.
common press, and to the dispensing with the attend-
ance of the man who inks the types; but in accom-
plishing this they found “that they were only em-
ploying a horse to do what had before been done by
a man.” 1 The attempt to improve the common press
was therefore abandoned; and the method of printing
by cylinders was tried. I A. small cylinder machine
having been constructed, it was ‘exhibited to‘ Mr.
Walter of the Times newspaper, and,on Kiinig’s stat-
ing what further improvements were contemplated,
an agreement " was entered into, for erecting two
machines for printing that journal. The machines
were in due course erected,'and on Tuesday the 29 th
of November, 1814!, the. Times announces the fact in
its leading article in the following .terms :,-—“ Gur
journal of this day presents .to the public the prac-
tical result of the greatest improvement connected
with printing, since the discovery of the art itself.
The reader of this paragraph now holds in his hand
one of many thousand- impressions of The Times
newspaper, which were taken off last night by a
mechanical apparatus. A. system of machinery almost
organic has been devised and arranged, which, while
it relieves the human frame of its most laborious
efforts in printing, far exceeds all human powers in
rapidity and despatch. That the magnitude of the
invention may be justly appreciated by its effects, we
shall inform the public that after the letters are
placed by the compositors, and enclosed in what is
called the form, little more remains for man to do,
than to attend upon and watch this unconscious agent
in its operations. The machine is then merely
supplied with paper: itself ‘places the form, inks it,
adjusts the paper to the form newly inked, stamps
the sheet, and gives it forth to the hands of the
attendant, at the same time withdrawing the form for
a fresh coat of ink, which itself again distributes, to
meet the ensuing sheet now advancing for impression,
and the whole of these complicated acts is performed
with such a velocity and simultaneousness of move-
ment, that no less than eleven hundred sheets are
impressed in one hour. That the completion of an
invention of this kind, not the effect of chance, but
the result of mechanical combinations methodically
arranged in the mind of the artist, should be attended
with many obstructions and much delay, may be
readily admitted. Our share in this event has, indeed,
only been the application of the discovery, under an
agreement with the Patentees, to our own particular
business; yet few can oonceive,--—even with this
.imited interest,—-the various disappointments and
deep anxiety to which we ‘have for a long course of

(1) In the Great Exhibition were several printing presses, in
which the types were inked by self-acting rollers. Such presses
would indeed require the strength of a horse to work them. We
have no doubt that much thought, anxiety and money were
expended in these inventions; but it was a pity that the inventors
had not been aware of Konig’s failure and the cause. A well ap-
pointed Museum of Mechanical Arts, on the plan of the Conserva-
toire des Arts at Métiers at Paris, with models or specimens of
machines, awell digested Index of Inventions, and with competent
persons to answer inquiries, would form an institution worthy of
the British nation, and be of essential service to inventors and the
progress of invention.

time been subjected. Of the person who made this
discovery we have little to add. Sir Christopher
Wren’s noblest monument is to be found in the
building which he erected; so is the best tribute of
praise which we are capable of offering to the inventor
of the Printing Machine comprised in the preceding
description, which we have feebly sketched, of the
powers and utility of his invention. It must suffice
to say further, that he is a Saxon by birth ; that his
name is Kdnig, and that the invention has been
executed under the direction of his friend and
countryman Bauer.”
Ten years later the Times again took up the subject
of this admirable invention, reasserting Mr. Kiinig’s
claims, which had been disputed in the interval, and
stating that their journal had been constantly printed
by the same method, to the great advantage of the
public from earlier publication and better press-work.
Mr. Kdnig, it appears, had returned to his native
country without having benefited to the full extent of
his merits by his wonderful invention and exertions
in England; but before he left this country he accom-
plished the last great improvement—namely, the
printing the sheet on both sides. “ In consequence
of successive improvements, suggested and planned
by Mr. Konig, the inventor,” says the Times (Dec. 3.
18242,) “ our machines now print 2,000 with more
case than 1,100 in their original state.” The notice
closes with a tribute to the strict honour and pure
integrity of the inventor, and the respect and esteem
in which he was held.
We put forward the claims of Mr. Kdnig on
the best of all authorities, that of the Times, which
encouraged and profited by his labours; and we do
this because, in all the accounts which we have read,
Kiinig’s machine is either not noticed or is referred
to contemptuously. This machine doubtless had its
defects,—the inking apparatus, for example, contained
40 wheels, and it sometimes took up 2 hours to get
the machine into working order,-—but it had also
great merits, not the least of which was that it served
as a model for subsequent inventors; and in saying
this we do not intend in the slightest degree to detract
from the merits of our respected friend, the late Pro-
fessor Cowper, nor of Mr. Applegath. Those gentle-
men, in 1818, patented a machine in which 2 drums
were introduced between the printing cylinders, and
the sheet was conveyed over and under these drums
in its progress from one printing cylinder to the other,
the effect of which was to ensure accuracy in register.
In this new machine was also introduced the plan of
distributing the ink upon the tables instead of the
rollers.
The printing of newspapers differs from that of
books in this respect, that in the former case, only
one side at a time is printed; but in the latter, both
sides. _It is easy to contrive a machine for printing
first one side of a sheet, and then, substituting the
inner for the outer form, to perfect the sheet by pass-
ing it through the machine a second time : but this me-
thod would not produce register ; the inner form would
not necessarily coincide with the outer in the perfected
i trauma/ageing azfirzamw @Qézfigo amigos: mags/saga .


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rrunrrne.
489
sheet; A little variation in this respect might not be
of importance in newspaper work, in which great des-
patch is required, but it is highly important to the
appearance of the work in book-work. It is also
a great advantage in newspaper-work to be able to
print the first side or outer form deliberately, and to
leave the making up of the inner form to the last
moment, and then to work it off. In order to print
both sides in register before the sheet leaves the ma-
chine, the object is to cause the sheet, after being
printed on one side, to travel over the surfaces of the
cylinder and drums at such a rate as to meet the
types for the second side at the exact point which
will cause the second side to fall with perfect accuracy
upon the back of the first. To accomplish this the
cylinder and drums must revolve at precisely the same
speed as the carriage underneath, and any inaccuracy
in the turning of the axles, the cutting of the teeth
of the wheels, or other deficiency, will produce defects
in the register. The ink, too, must be properly dis-
tributed, and the face of the type be perfectly covered;
the inking apparatus must also be under complete
control and in good working order. The various in-
genious contrivances by which these objects have
been attained, will be understood by referring to the
steel engraving, and to the following description.
The blank paper, which is to be printed, is laid on
a table T, by the side of which, on a raised platform,
stands a boy, called the layer-on, who places the paper,
a sheet at a time, upon the feeder F, which has a
number of linen girths or tapes passing across its sur-
face, and extending to a roller at each end of the
feeder, so that when the rollers are partially turned
round, the motion of the girth carries the sheet for-
ward under the web roller 20 and the smoothing roller
8, and delivers it over the entering drum n. The
partial revolution of the feeder is accomplished by
attaching to its axis the small quadrant Q; this is
raised by means of the large wheel W, to the side of
which is a toothed segment a:, so that for every revo-
lution of the large wheel the quadrant is made to
revolve through a space sufficient to cause the feeder
to carry in the sheet, and when the toothed segment
has passed the quadrant, the latter falls down again,
ready to be raised as the wheel comes round. By
this means, provided a sheet of paper be placed upon
the feeder once during every revolution of the large
wheel, the quadrant takes it into the machine at the
right moment, and thus prevents it from occupying
a wrong position or interfering with the sheet which
is actually being printed. The feeder, then, delivers
the sheet of white paper to the entering drum n,
where it is seized between two systems of endless
tapes, which pass over a series of rollers to keep them
extended. These tapes are so contrived as to fall
between the pages of the printing and on the margins
or edges of the sheet : this allows them to remain in
contact with both sides of the sheet during its entire
passage through the machine, and in this way the
paper is conveyed from the printing cylinder r to the
other printing cylinder 1?’ without distinbing the
register or coincidence of the pages on opposite sides

of the sheet. The printing cylinders are of iron turned
quite true, and are covered with Man/sets of fine
woollen cloth: they are mounted on strong axes,
which turn in bearings attached to the main frame of
the machine. These bearings can be adjusted by -
means of screws to suit the amount of pressure re-
quired. The, sheet is conveyed from one printing
cylinder to the other by means of the conveying
drums o 0', which are of wood. The cylinders and
drums are all connected by toothed wheels, so as to
ensure a uniform and steady motion. The convey—
ance of the sheet with accuracy and speed by means
of the tapes is an important feature of this machine.
One system of tapes may be said to commence at the
feeding apparatus 1?: from this they proceed in con-
tact with the right-hand side and under portion of
the printing cylinder r: they then pass over the con-
veying drum 0 and under the conveying drum 0',
whence they proceed to encompass the left-hand side
and under portion of the printing cylinder 1?’, and by
passing in contact with the small rollers r r’ r2 r3 they
arrive again at the feeder 13‘, thus forming one of the
series of endless tapes. This is shown by the con—
tinuous line in the diagram Fig. 2 of the steel en-
graving. The other system of tapes corresponds with
the first in number and position in such a way, that
the sheet of paper, so long as it is grasped between
them, may be held securely and yet be in constant
motion. Commencing with this second system of
tapes at the feeding apparatus, they descend there-
from to the entering drum E, where they meet and
coincide with the first system in such a manner as to
proceed together under r, over 0, under 0’, and round
r’, until they arrive at the roller 2f2,where they separate.
From the roller #3 the tapes descend to the rollers z." #2,
and proceeding up to the stretcher #3, pass under or
over the supporting bar 6, and proceed to the point
from whence they commenced. The dotted line in
Fig. 2 of the steel engraving will show the arrange-
ment of the second system of tapes.
The two forms of type required to print the sheet
on both sides, are placed at a certain distance from
each other on a long carriage, and close to each form is
an inking table consisting of an extended metal surface
also supported by the carriage. The carriage moves
backwards and forwards from one end of the machine to
the other on rollers attached to the main frame of the
machine, and in its progress to and fro it brings the
types at the proper moment in contact with the sheet
of paper on one of the printing cylinders. This
reciprocating movement is produced by a pinion
working into the alternate sides of a rack under the
tables, and motion is given to the pinion by bevel
wheels. The mechanism for supplying the proper
quantity of ink, for distributing it equally over the ink-
ing-table, and then applying it to the types, is ingenious
and effective. There is of course a complete set of
apparatus attached to each form. The metal
roller cl, called the ductor roller, has a slow rotatory
motion imparted to it by means of a catgut band
passing round two pulleys, one of which, p, is attached
to the axis of (Z, and the other to the axis of the
490
PRINTING.
printing cylinder r’. A horizontal plate of metal,
the edge of which is ground straight, is adjusted by
screws, so as to be nearly in contact with the ductor
roller; and a back being put to the horizontal plate,
the whole forms a sort of trough I for containing the
mass of ink, and as the metal roller revolves, it
becomes covered with a thin film of ink. An elastic
composition roller, called the vibrating roller, shown
at e, in Fig. 3, is by means of the rods or, or,
moved by a small cam attached to one of the large
wheels w, made to vibrate between the ductor roller
and the inking table. When the vibrating roller
rises, it comes in contact with the ductor roller,
takes from it a small portion of ink, and descend-
ing, deposits it on the inking table. Three or four
rollers of smaller diameter cl r, called clisl'rituiiiig
rollers, are placed somewhat obliquely across the
machine. The spindles of these rollers are made
long, and theylie in notches, and not in fixed bear-
ings. As the table moves under them, they not only
rotate, but have also a motion in the direction of
their length in consequence of their oblique position,
and this compound motion produces a perfect distri-
bution of the ink on the inking table. The inking
table then passes under 3 or It inking rollers ir, to
which it conveys the distributed ink, and they in
their turn ink the type f; so that every time the
type passes to and fro, that is, every time a sheet is
printed, the form f is touched no less than 8 times
by the inking rollers. The distributing rollers (Z r,
and the inking rollers ir, all turn in notched bearings
so as to allow them to move up and down, in order
that they may bear with their weight on the inking
table and the form: hence they require no adjustment
by screws, but are ready for work by being dropped
into their notched bearings. The machine is put in
motion bya strapproceeding from a rigger and round
the drum 1), which has a fast and a loose pulley.
The strap can be shifted from one to the other by
means of the forked lever le, which is under the com-
mand of the feeding—boy, so that the machine can be
set going or stopped in an instant. These machines
require no very great power to turn them. Messrs.
Clowes of Stamford Street found two five-horse
engines sufiicient to work twenty of these machines.
It is scarcely necessary, after the above description,
to state the working of this machine. The sheets of
blank paper are placed one by one on the feeder F.
The feed-rollers are made to move by means of a
segmental wheel Q, which advances the sheet of paper
sufiiciently to allow it to enter between the two
systems of endless tapes at the point where they
meet each other on the entering drum E. As soon
as the sheet is fairly between the tapes, the feed-
rollers are, by the operation of a. weight 20’, contained
in the weight-case w’ e, drawn back to their original
position, ready to advance another sheet into the
machine. As the sheet is carried along between the
endless tapes, it applies itself to the blanket on the
printing cylinder 1’, and as it revolves, it meets the
first ‘form of types, and receives the impression from
it. The sheet, now printed on one side, is carried

over 0 and under 0’ to the blanket on the printing
cylinder 1?’, where it is now in an inverted position,
with the printed side in contact with the blanket, and
the white side outwards, and this, upon meeting the
second form of types at the proper instant, receives
the second impression, and completes the sheet. On
arriving at the point where the two systems of tapes
separate, the perfect sheet is thrown out upon the
table r’, where it is taken out by a boy, and arranged
with the other printed sheets in a heap.
It is to a machine of this kind that we are in-
debted for most of the cheap literature of the day.
That which the railway, the locomotive engine, and
the steam-boat have done for locomotion and traffic,
the printing-machine has accomplished, for education
and intelligence. Without the printing-machine,
cheap literature could not have existed; English
Bible Societies could not have scattered in such pro-
lific abundance the word of God over the world, and
the newspaper-press—that true exponent of a free
people—must have remained comparatively ineiiec-
tive. .
The printing-machine, however, such as we have
described it, ‘proved inadequate to the demand for
newspapers. In 1827, Messrs. Cowper and Apple-
gath conjointly invented the four-eg/lirzeler machine,
which Mr. Applegath erected for printing the Times
newspaper. That it immediatelyr superseded Konig’s
machines will readily be supposed, when it is stated
that the latter produced only 1,800 impressions per
hour, while the former prints from 4,000 to 5,000 im-
pressions within the same time. Fig.1'753 will convey
a general idea of these machines, which are still used
at the Times oiiice for printing the Supplement‘, or
for that form of the paper containing advertise-
ments, &c., which allows of more time in the prepa-
ration and working than the form which includes
parliamentary debates, latest intelligence, &c. Each
of these machines consists of a table a, moved back-
wards and forwards under the 4: iron cylinders l,
called the paper cylinders; ‘these are each about 9
inches in diameter, and are covered with Mam/eel.
The sheets of paper are held round these cylinders
by means of tapes, as already described. The form
of types is fixed on one part of the table a, the
inking rollers e occupy another part of the table, on
which they distribute the ink; (l is the ink-trough; e
is the elastic roller vibrating between the ductor roller
and the table. This machine is fed by four boys,
named layers-0n, who lay the sheets of paper one at
a time on the feeding-boards j; whence they enter
the machine between 3 pairs of tapes, by which they
are conveyed round the cylinders, and thence to the
positions 99', where four boys named letters-of stand,
who receive the printed sheets as the tapes separate.
Machines of ‘this kind continued to supply the
Times until the year 184:8. The increased supply which
they ail'orded stimulated an increased demand; nor
need we feel surprised that a journal conducted with
so much intelligence and honesty of purpose, written
with so much skill—often, indeed, amounting to
genius,—-—that a journal which has long proved itself
PRINTING.
491
to be the consistent advocate of the poor, the injured,
and the oppressed, and the unflinching opponent of
the selfish, the unjust and the mean; that such a
journal, shedding not only an informing light on the
politics and news of the day, but advocating with a
master-hand the claims of literature and science, the
fine arts, and the useful arts,--of everything, in short,
that is calculated to advance civilization, and to pro-
mote the dignity and happiness of the human race,—








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Fig. 1753.
to Fig. 1753, that the forms of type and the inking
table have to travel backwards and forwards for each
revolution of the paper or printing cylinder—back-
wards to be inked, and forwards to be printed. In
the Times machine, the frame has a motion of 88
inches in each direction. Now it is evident that in
the reciprocating motion there must be two dead
stops for every revolution of the printing cylinder,
and if the machine be worked at a high rate of speed,
the momentum acquired by the heavy metal table
must render it liable by its sudden stoppage to rupture
some part of the apparatus. It was found, moreover,
that in sheets of so large a magnitude as those em-
ployed in printing the Times, each layer-on could not
deliver them with the required precision at a more
rapid rate than 2 in 5 seconds, or 25 per minute, which
is at the rate of 1,500 sheets per hour; or with 41 cylin-
ders, and a layers-on, 6,000 sheets per hour. It was,
however, required to produce at least 10,000 sheets per
hour, and this it was found would require '7 printing
cylinders, the arrangement of which in one machine
presented mechanical dificulties of a very formidable
kind. Mr.Applegath therefore determined to abandon
the reciprocating motion of the table, and to adopt
a continuous circular motion. We may suppose his
I





we cannot wonder, we repeat, that the circulation of
such a paper should be to a great extent limited only
by the power of multiplying the number of its
copies. The increased demand was met by Mr.
Applegath by the invention of an entirely new
machine, which we now proceed to describe. But
before doing so, it is necessary to state in what con-
sisted the limit of speed in the former machine. It
will be seen on reference to the steel engraving, and




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§ \



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./_///%


“stream aim cswsm’s Timéé iiiicnmn.
first crude idea to have been to set up the old machine
on one of its sides, so that instead of therdi‘ums and
cylinders moving on horizontal axes, they should
move on vertical axes. In the machine as it actually
exists, there is a central drum, Fig. 1754.‘, 200 inches
in circumference, or 64: inches in diameter, capable of
moving on a vertical axis. The inking table and the
columns of type are secured to the surface of this
drum : the columns of type are placed vertically, not
conforming to the curve of the drum, but forming
the sides of a polygon, the axis of which coincides
with that of the drum. This is contrived in the
following mannerz—A slab of iron is curved on its
under side, so as to fit the large cylinder, while its
upper surface is filed into facets or flat parts, corre-
sponding in width and number to the width and number
of the columns of the newspaper; between each column
there is a strip of steel, with a thin edge to print
the “rule”-~the body of this strip being wedge-shaped,
so as to fill up the angular space left between the
columns of type, and to press the type together side-
ways, or in the direction of the lines; the type is
pressed together in the other direction by means of
screws, and is therefore firmly held together. The
surface of the type thus forms a portion of a polygon,
4192
PRINTING.
as already noticed; and the regularityl'of the impres-
sion is obtained by pasting slips of" paper on the
paper cylinders. The large central drum is sur-
rounded by 8 cylinders, each about 13 inches in
diameter, also with vertical axes. They are covered
with cloth, and upon them the paper to be printed is
carried by means of tapes. Each of these cylinders
is so connected with the central drum by means of
toothed wheels, that the surface of each must move
with the same velocity as the surface of the drum.
It will thus be evident, that if the type on the drum
be inked, and each of the cylinders be properly sup—
plied with a sheet of paper, a single revolution of
the drum will cause the 8 cylinders to revolve also,
and produce an impression on one side of each of
the sheets of paper. But for this purpose it is
necessary that the type be inked 8 times during one


, willllllli,


revolution of the drum. This is accomplished‘ by
means of 8 sets of inking rollers, one for each paper
cylinder. The ink is held in a vertical reservoir (sup-
5plied from above), formed of a ductor roller, against
which rest two straight-edges connected at the back,
so as to prevent the ink from running out. It is
conveyed from the ductor roller by one of the inking
rollers in the following manner :-—-As the inking
table on the revolving drum passes the ductor roller,
it receives from it a coating of ink; and then coming
immediately in contact with the inking rollers, it inks
them; the types next follow and receive from the
inking'rollers their coating of ink, and the drum, still
revolving, brings the inked type into contact with
the paper cylinders, and the sheet is printed. It
must not be forgotten as one of the distinguishing
features of this machine, that the various processes




ii
Hum - -.




lllllltlllllltllllllllfiillll
l,l_

Fig. 1754. APPLEGATH’S Times VERTICAL PRINTING~MACHINE.
which have just been enumerated for one set of
inking rollers, and one paper cylinder, are repeated
8 times for every single revolution of the central
drum, so that in this period 8 sheets are printed, and
turned out of the machine. For this purpose it is
necessary to supply the 8 cylinders each with a sheet
of paper. Over each cylinder is a sloping desk, ii,
upon which a number of sheets of white paper are
placed. The layer-on stands by the side of this
desk, and pushes forward the paper a sheet at a
time towards the tape fingers of the machine. These
tapes seize it and draw it down in a vertical direc-
tion between tapes in the 8 vertical frames until
its vertical edges correspond with the position of
the form .of_ type on the drum. When in this position
its vertical .motion is arrested for a moment, it then
moves horizontally and is carried towards the printing
cylinder by the tapes. Passing rollild this cylinder,
it is instantly printed. It is then conveyed horizon-
tally by means of tapes to the other side of the frame,
and is moved along to another desk, where the taker‘
off pulls it down. As soon as one sheet is thus
disposed of, accommodation is made for another, and as
each layer‘on delivers' to the machine 2 sheets every
5 seconds, 16 sheets are thus printed in that brief
space, and this is ‘continued for any length of time,
supposing no accident occurs, such as a sheet going
wrong, in which case it is the duty of the taker-off to
pull a bell handle, and the machine is instantly stopped
by the engineman. As the type form on the central
drum moves at the rate of 70 inches per second, and
the paper to be printed moves at the same rate, if by
any error in the delivery or motion of a sheet of

paper it arrive at the printing cylinder elgth of a
PRINTING.
493
second too soon or too late the relative position of
the columns on one side as compared with those on
the other side of the paper will be out of register by
715th of 7 0 inches, viz. 1 inch, in which case the edge
.of the ,printed matter on one side will'be an inch
nearer to the edge of the paper than on the other side.
By inaccuracy in the delivery of the paper to the
machine, we do not mean‘ that each layer-on must
deliver his sheet at the right instant of time; this
would lead to strange irregularities and render fast
printing impossible. No; all he has to do is to draw
forward the sheets so as always to have the edge of
one ready for the machine to take in, which it does
by the mechanism which we are about to describe in
the following detailed account. If the steam engine
which works the machine be put on a greater speed,
the central drum and all the attendant apparatus

would work with greater rapidity, and such a speed
might easily be attained as to render it impossible for
the layers-on to present the paper fast enough to
satisfy the improved appetite of the machine; but in
any case the machine would not take in the sheets as
the layers-on chose to present them, but only at those
periods, rapidly recurring though they be, which are
provided by the peculiar functions of the machine.
There is in fact an apparatus provided, the function
of which is similar to the segmental wheel Q, noticed
in the description of the two-cylinder machine. In
the following figures the same letters of reference
refer to the same parts of the machine.
a, a, is the large vertical drum, forming the centre
of the system, mounted on the shaft 6, b, and driven
bythe bevel wheel and pinion c, d, the shaft of the pinion
a? being supported on the floor, and carried to the prime

Fig. 1755.
mover, which in this case is a direct action or disc
steam engine. ff; are the 8 impression cylinders,
driven by the spur wheel e; the same speed is there-
fore secured between the circumference of the drum
(with the type) and the circumference of each im-
pression cylinder. The columns of type, as already
mentioned, are fixed in the four type holders g, 9.
Between the columns of type are the rules, which are
fitted into the top and bottom of the type holder in a
similar way to a metal saw in its frame. These rules
are made like the keystone of an arch, to fill up the
space left at the junction of the columns, owing to
the angle which the columns form with each other in
their position as sides of a polygon. In order to
avoid the possibility of the type escaping from its
place, in screwing it up, the centre rule in the type
holder is a fixture; and each column is jammed up

ELEVATION.
from one end by a set-screw, as shown at top and
bottom of the upper and lower type holders, Fig.
17 55. The four pages of type thus prepared are
bolted to the rings of the central drum. It will be
observed that the impression cylinders are not ar-
ranged symmetrically around the central drum. A
greater space is left between one pair than between
the others, in order to give room to get at the type,
which can only be done when it is in the position
shown in Fig. 17 541.
One of the systems of apparatus for supplying the
impression cylinders with sheets of paper, is shown in
Fig. 1757. This will enable the reader to understand
how the paper is brought to a vertical position, and
moved laterally in its passage through the machine.
The sheets of paper are piled on the feeding board [2,
Figs- 1754, 1757, and are pushed forward, one by
419%
PRINTIN G-
one, by the layer- on, over the centre of the feeding
drum i, Fig. 1755, le, ls, are two small fluted rollers,
fixed on the dropping bar, and driven by tapes off the
roller l. At the right moment this bar turns on its
centre l, and is is drops, as shown in the figure, and
by its motion advances the sheet of paper between
the rollers i and l. The motion of the sheet is then
continued downwards by~tapes passing around the
rollers m, m, and 72, ii. The paper is steadied in the
Gap fa

LP
M
H
DD
e:











in” uni/7,}!
its "r


,1 '\ i‘,
r
. ti


Fig. 1756.
PLAN.
whole of its course by numerous tapes, only a few of
which are represented. The down tapes pass round
the feeding roller and the smaller rollers m, m, and ii,
92, and carry the sheet with them until its progress is
arrested by two long narrow strips of wood 0, 0,
covered with 'woollen cloth, and called “stoppers,”
one pair of which is advanced forward against the
other pair, which is fixed. The motion pf this stopper
frame is effected by means of the cam 10, Fig. 1757,
which acts upon the arms q g, g 9, attached to the

frame. The rollers m, m, and ii, a, and the tapes
with them, open, and leave the sheet in its vertical
position, held up by the stoppers. The opening of
the rollers m, m, and ii, 72, is effected by their bearings
being mounted in the ends of levers, and these levers
are made to act upon each other by means of the
toothed segments shown in the figure. The cam r
lifts the link 8, which moves the top pair of rollers
m, m, while the motion is conveyed to the lower pair,
0
give
EF
3



f
m it





G *1
Fig. 1757. END VIEW or ran FEEDING APPARATUS.
kg
ii, 72, by the connecting rod i‘, which is loaded with a
weight at bottom to keep the friction roller on the
cam r. The sheet of paper being held up by the
stoppers, the latter are now relaxed, and the weight
of the paper is taken by two pairs of small fingers, or
suspending rollers, at the top of the sheet, which are
brought together by a cam, and, pressing slightly
together, hold the sheet up during the instant of time
that the stoppers are relaxing, and until the three
pairs of vertical rollers 26 26, me, a ll, Figs. 17 55, 1757,
PRINTING.
' 4.795
are brought into contact to communicate the lateral
motion to the sheet. The vertical rollers are all
driven at the same speed as the printing drum by
means of bevel wheels and pinions, as shown. The
three front rollers, 24, u, u, are mounted in a hanging
frame a, a, and the pinions at bottom are driven
through the bevel pinions and the shaft w, w, which
is made with a universal joint to allow of the motion
of the frame 0, v. The back rollers are driven in a
similar way, but their centres are stationary.
The proper motion is communicated to the hanging
frame 22, v, by a cam, similar to p, acting upon the
lever and friction pulley 0:, the motion being commu~
nicated through the levers y, y, Fig. 1757. Imme—
diately on the rollers being brought into contact with
the paper, it is advanced by their motion into the
mouth of two sets of horizontal tapes, which pass
round the drums 2 and 3, (also driven by gearing)
and carry the sheet onwards towards the impression
cylinder j} where it is printed, and whence it returns
in the direction of the arrows, the dotted line showing
its path. The sheet of paper in its passage out meets
with another set of endless tapes at the roller 4:, Fig.
1756, which assist it out as far as the roller 5, where
these tapes return and leave the sheet to complete its
course by the action of a single pair of suspending
tapes at the top of the sheet, and pressed lightly
together by the pulleys 6. On arriving at the outer
pulley these tapes are forcibly pressed together by a
lever and stopped, and thus hold the sheet of paper
suspended and ready for the taker-off to draw down,
and place on the taking-off board 7 ——an operation
very easily performed.
The method of counteracting the deviation of the
faces of the columns of type from a true circle is as
follows: strips of paper are pasted down the impres—
sion cylinder, in width equal to each column. Other
narrower strips of paper are pasted in the centre of
these, and other strips, narrower still, until the sur-
face of the impression cylinder becomes a series of
segments of smaller circles, agreeing sufficiently with
the required curve to produce a perfect impression of
the type over the whole width of the column.
The ink is supplied to the type by 3 inking-rollers
(shown on the type pg, Fig. 1755), between each 2 im-
pression- cylinders. These rollers receive their ink from
revolving in contact with a curved inking table, placed
on the central printing drum opposite to the form of
type. The ink is communicated to the inking table
by two vibrating rollers, alternately in contact with it
and the ductor roller. The ductor roller 9, Fig. 17 5 6,
forms one side of an ink-box from which, as it revolves
by the bevel gearing, 10 and 11, it withdraws a por-
tion of ink. The two ink-boxes are kept full by a
reservoir placed above them. The rollers are
caused to press in contact with the inking table by
means of coiled springs, as shown, and their brass
bearings are also furnished with set-screws to hold
them in close contact with the type, as it passes, in a
similar manner to other quick machines. The spindles
of the inking rollers are also provided with small fric-
tion wheels at top and bottom, which run upon a

brass bearer on the central drum; by which they are
kept from being drawn into the drum by their springs,
except at the proper time. There is an advantage
incidental to the vertical position of the type and the
paper; viz., that the ink does not sink into the type
as it does when it is placed horizontally, and on that
account the type is kept much cleaner.
In looking at a copy of the Times, it will occasion—
ally be observed that the impression is not exactly in
the centre of the paper. Now, the only wonder really
is, that it should be so nearly true. The type and
the paper move at about the rate of 6 feet per second,
so that an error in the arrival of a sheet of paper to
the impression cylinder of ,15th of a second would
cause an error of 1 inch in the margin. Yet so accu-
rately is this performed, that the waste of sheets is
considerably less with this machine than with the old
horizontal ones.
Some little difficulty was experienced at first in
carrying on the paper, when vertical, without buckling
it. This difficulty was conquered by introducing an
additional roller, to give the paper a slight angle, in-
stead of drawing it out in a straight line, which had
the effect of stiffening it, on the same principle as
corrugating a plate of iron.
The produce of this machine might readily be
doubled, by having two forms of type on the central
drum, instead of one, and if there were not space for
two machines, the additional eight laying~on boards
and feeding drums might be made in a story above
the present ones) '
The following are interesting statistics relative to
the printing of the Times .--—On the 7th of May, 1850,
the Times and Supplement‘ contained 72 columns, or
17,500 lines, made up of upwards of 1,000,000 pieces
of type, of which matter about ‘glths were written,
composed, and corrected after 7 o’clock in the even-
ing. The Supplement was sent to press at 7.50, P.M.,
the first form of the paper at $.15, A.M., and the se
cond form at 41.115, A.M.; on this occasion 7,000 papers
were published before 6.15, A.M., 21,000 papers be-
fore 7 .30, A.M., and 34,000 before 8.415, 11.11., or in
about four hours. The largest number of copies ever
printed in one day was 70,000, and this was on the
létth of November, 1852, the day after the Duke of
Wellington’s funeral. As there was no supplement
on this day, the whole of the impression was printed
at the two vertical machines, one of which now prints
11,000 per hour, and the other 12,000 per hour, not
including stoppages. The whole of this enormous
impression was worked without once washing the
rollers or brushing the form. As such numbers as
these may not convey to every reader an adequate
idea of the enormous amount of material consumed in
the publication of this wonderful journal, we may

(1) Mr. Applegath’s machine was described by the late Professor
Cowper, in Mr. Weale’s “London Exhibited,” 1851. There is
also a carefully prepared account of the machine in the Artizan ,-
and in the Mechanic’s Magazine, No. 1509, is an account of
Mr.App1egath’s new vertical machine, which is capable of print-
ing 16,000 per him We have to thank Mr. J. Applegath, 0f the
Times ofiice, for his attention to our wishes during several visits
to his brother’s printing machine.
4.96
PRINTING.
state, that the paper for a week’s impression fills 13
waggons; and that the whole of one day’s impression,
taking it at 42,7 50 copies, weighs about 7 is tons.
Snc'rron VL—Srnnno'rrrrne.
It will be seen, by reference to a former Section,
how numerous and complicated are the processes re-
quired in the preparation of the two forms of a printed
sheet. The type previously distributed has to be com-
posed, and the pages imposed; a proof is taken and
read ;1 the errors marked thereon are corrected; a
second proof is taken and read, and the errors are cor-
rected; then there is‘ the author’s proof, and the press
proof: we have, in fact,‘a number of persons all in-
terested in detecting blunders, and when at length
the sheet is pronounced correct, and is sent to press,
a small number only‘ may be required, such as 250,
500, or '7 50. This number being worked, the forms
are unlocked, and the type is distributed; so that all
this care and anxiety bestowed upon every sheet of
the work, must be bestowed again (with the exception
perhaps of the author’s proof) if the work is required
to be reprinted.
The great majority of works, however, which issue'
from the press, never attain the honour of a reprint
or a second‘ edition, while there are other works for
which there is a constant daily demand. This was
found to bathe case soon after the invention of print-
ing, and the plan adopted by the continental printers
was to set up the whole of the work which was in
request, and to keep the type standing for future
editions.’ This enabled the printer to work off as
many copies at a time as he had demand for, and so
not encumber his warehouse with useless stock ; and
it also enabled him to sell the work at a very much
cheaper rate than if the type had to be composed, &c.
for each edition. The disadvantages of the plan were
the large outlay for type, the space occupied by the
forms, and the liability to damage from the dropping
of letters, batters, and other accidents. Attempts
appear to have been made early in the 18th century
to cement the types together atthe bottom with lead
or solder, in order to their more perfect preservation.
Camus states,1 that in June 1801 he received a letter
from the Luchtrnans, booksellers of Leyden, with'a
copy of their. stereotype bible, the plates for which
were formed by soldering the bottom. of common
types together with some melted substance to the
thickness of about 3 quires of writing-paper; and,
they add, “these plates were made about the begin.-
ning of the last century by an artist, Van der Mey,
at the cost of our late grandfather, Samuel Luchtman,
bookseller.”
This, however, does not appear to us to be a case

(1) “ Histoire et Procédés du Polytypage et de la Stéréotypie.”
It appears from-this work, that about the year 17 35 the French
made use of casts of the calendars placed before their church-
books. A specimen 'of one of these plates, examined by Camus,
an impression ‘from which is given in his work, was of.copper, 3%
inches long, 2 inches broad, and %th inch thick. From the rough-
ness of the castingfit appeared to have been made in a mould of
sand or blay.~'_~§l,‘he back had been dressed with a file, and then
attached to a block of wood. -

in point. The art of stereotyping 2 consists in making
perfect fac-similes in type-metal of the face of the
pages composed in moveable types. These fac-similes
' being made, the type is released, and may be distributed
and serve for the setting up of fresh pages, which
may again furnish, as it were, the punches to the
mould into which the type-metal is poured for the
purpose of making the fac-simile. The great value
and distinguishing feature of stereotyping is, that the
type is released, whereas, in Luchtman’s process, it
is sacrificed, and cannot be‘ distributed or used again
for any other work. The first person who appears
to have suggested the casting of plates from the pages
of type was William Ged, a goldsmith of Edinburgh,
who, about the year 1725, being in company with a
printer, who was lamenting the want of a good letter-
founder in Scotland, Ged suggested the multiplication
of the composed and corrected pages by means of
casts; so that a small stock of type might serve forv
the perpetuation of a large number of works. He
soon after produced a specimen of the new art, but'
wanting capital to perfect and carry out the idea, he
made certain proposals to a man of property, who
looked into the plan, but retained his money in his
own safe keeping. Ged then visited London, and
sought the patronage of the London Stationers; he
was encouraged with words, but received no substan-
tial assistance. He next submitted his scheme to
the Universities and to the kin'g’s printer, and met with
the support which he required. He stereotyped some‘
bibles and prayer-books, and the sheets worked ofi
from his plates were admitted to be equal to the
printing of the day. But now, while the success of
his scheme appeared certain, new difficulties arose.
The argument used by the idol-makers of old,2 “ Sirs,
ye know that by this craft we have our wealth,” and
that, “this our craft is in danger to be set at nought,”
was, as is "usual in such cases, urged against this
most useful and important invention. The com-
positors refused to set up works for stereotyping, and
even those which were set up, however carefully read
and corrected, were found to be full of gross errors.
The fact. was, that when the pages were sent to be
' cast, the compositors or pressmen, bribed, it is said,
by a type—founder, disturbed the type and introduced
false letters and words. Poor Ged died, and left the
dangerous secret of ‘his art (which he did not disclose
during his life- time) to his son, who, after many
struggles for success, failed as his father had done
before him; and yet the very men who were the loud-
est in their cry, “ Great is Diana of the Ephesians I”
----who had rejected Ged’s plans—now used his plates,
although they knew not how to produce more. 11-
liberal policy is always short-sighted. If Ged’s oppo-
nents had been less selfish, they might have foreseen
that the new art would have increased the demand
both for type-founders and for compositors, as it'has
done since its general adoption. Indeed, it were
not for stereotyping, alarge number of valuable works
would rapidly go out of print ; bibles and prayer-books

(2) 2169669, solid; 767709, atype. (3) Acts xix. 25, 27.
PRINTING.
497
could not be produced in such vast numbers, and at
so cheap a rate as they now are, and the continued
sale of such Works as the present Oyclopaedia would
be impossible. The effect of the opposition to Ged’s
invention was to cause the art to be forgotten for
half a century. It was then revived by Dr. Tilloch,
who contrived a method for producing stereotype-
plates, and printed several volumes with them. The
art was not, however, of much practical value, until
Lord Stanhope took it up: he engaged the services
of a London printer, named Wilson, and at length
matured the plan such as it is at present practised.
The type employed in stereotyping differs some—
what from that in common use. The letter should
have no shoulder, but should rise in a straight line
from the foot: the spaces, quadrats and leads are of
the same height as the stem of the letter, the object
being to diminish the number and depth of the cavities
in the page, and thus lessen the chances of the mould
breaking off and remaining in the form. Each page
is carefully corrected, and imposed in a small chase
with metal furniture, which rises somewhat higher
than the type. The number of pages in the form may
be 1, 2, 3, or more, according to the size of the book;
the smaller the page, the larger the number. The
surface of the type is next rubbed over with a soft
brush holding a small quantity of very thin oil.
Plumbago is sometimes preferred. A brass rectangular
frame of three sides with bevelled borders adapted to
the size of the pages is placed upon the chase so as
to inclose three sides of the type, the fourth side
being formed by a single" brass bar having the same
inward sloping bevel as the other 3 sides. The frame
thus formed, Fig. 1758, serves to define the area and
thickness of the cast, which is next taken in plaster-of-
paris, for which purpose two degrees of fineness of

Fig. 1758.
plaster are used; the finer quality is mixed, poured
upon the surface of the type, and gently worked in
with a brush so as to ensure contact and exclude air
bubbles. A large quantity of the coarser plaster mixed
with water is then poured and spread over the previous
layer, but without disturbing it. A straight-edge is
passed over the moulding frame, to clear away the
superfluous plaster and leave that in the frame of
VOL. II.

uniform thickness. The plaster mould ‘soon sets, and
the mould-frame is raised and the mould comes off
from the surface of the type, the film of oil or plum-
bago preventing the adhesion of the plaster. The
plaster mould is dressed and placed on its edge in one
of the cells of a sheet-iron rack contained in an oven,
and exposed to the temperature of at least A000 for
about 2 hours, when it becomes perfectly dry. A good
workman will mould 10 sheets 8vo. or 160 pages in
a day:~ each mould generally contains 2 pages 8V0.
The mould is now very friable and must be handled
with delicacy; it is placed with the face down upon
a flat cast-iron plate called the floating-plate: this is
placed. at the bottom of a square tray of cast—iron
with the upright edges sloping outwards, called the
dipping-pan, Fig. 1759. A cast-iron lid is applied to
it and secured by a screw s, and shackles s’ s’. The
pan is heated to 400° before the plaster mould
is put into it, and is next plunged into an iron pot


Fig. 1759.
placed over a furnace, containing the melted alloy,
the pan being slightly inclined to allow the air to
escape. There is a small space between the back
or upper surface of the mould, and the lid of the
dipping-pan, and the fluid, metal on entering into the
pan through the corner openings 00, floats up the
plaster together with the iron plate (hencecalled the
floating pic/e) on which the mould is placcdf’tlie' effect
of which is that the metal flows through the notches
cut in the edge of the mould and fills up every part
of it, forming a layer of metal on its face correspond-
ing to the depth of the border, while only a thin metal
film is left on the back of the mould. The dipping
pan is suspended, plunged in the metal, and removed,
by means of a crane, and when taken out it is put
into a cistern of water upon bearers so arranged that
only the bottom of the pan is in contact with the
surface of the water. The metal thus sets from
below, and remaining fluid above, it maintains a fluid
pressure during the shrinking which accompanies the
cooling. As it thus contracts in volume, melted
metal is poured into the corners of the pan for the
purpose of keeping up the fluid pressure on the mould
and thus obtaining a good and solid cast. If the pan
were left to cool more slowly, the thin film of metal at
the back of the inverted plaster mould would probably
solidify first, and thus prevent the fluid pressure
which is required for filling up all the lines of the
mould. A good workman will make 5 dips, each con-
taining 2 pages 8vo., in the course of an hour, or
' x x
498
PRINTING.
about 9%,,— 8vo. sheets per day. When the pan is
opened, the cake of plaster and metal is taken out and
beaten upon its edges with a mallet, to remove super-
fluous metal. The stereotype plate is then taken by
the pic/ter, who planes its edges square, turns its back
flat upon a lathe to the required thickness, and re-
moves any minute imperfections occasioned by specks
of dirt or air bubbles left among the letters in casting
the mould. If any of the letters are damaged they
are cut out, and separate types soldered in instead.
The plate is now ready for working, and when made
up with the other plates into the proper form it may
be worked either at press or by machine.
In January 1816, Professor Cowper took out a
patent for curving stereotype plates, fixing them on a
cylinder, and printing with them. The plates were
heated to prevent them from cracking in the bending.
The inking apparatus had no end motion to the
rollers, but the plates passed under several rollers.
The ductor roller was employed.1
Other methods of stereotyping or of polytyping
have been contrived at different periods. In 1791,
M. Carez, a French printer, adopted the following
method :--A page of moveable types well looked with
screws was attached to a heavy piece of wood sus-
pended with the face downwards from a beam, and
this was allowed to fall suddenly upon lead in a state
of fusion, but just on the point of solidifying. In
this way a punch or matrix for a whole page was
obtained, and was used for making relief stereotypes by
attaching it to the block of wood already referred to,
and letting it fall on fusible metal just on the point
of setting. In this way good poly/page plates were
obtained, but there was danger of melting the types
if the lead were too hot, or of bruising them if it were
too cold. After various attempts to remedy these
defects, M. Firmin Didot adopted the following plan.
He cast his types in a very hard alloy, composed of

(1) In our last section, the claims of Professor Cowper as an in-
ventor of steam-printing machinery were not stated with suflicient
fulness. We take this opportunity of supplying the information.
In the year 1818 Professor Cowper patented a machine, in which
drums were introduced between the printing cylinders of machines
for printing both sides of the sheet, which was conveyed over
and under these drums in its progress from one printing cylinder
to the other. The effect of this arrangement was to ensure accu-
racy of register by keeping a firm hold upon the sheet, and prevent-
ing it from shifting between the endless tapes by which it was
conveyed. In this patent was also contained the plan of distribut-
ing the ink upon a. flat table instead of upon a roller. The inking-
table passed backwards and forwards under rollers, which received
an end motion at the same time by means of an indentation along
the edge of the table acting upon a frame in which the rollers
were mounted. This apparatus solved the problem of obtaining
a perfect distribution of the ink. The combination of the inking-
table, and trough, and hand-roller, now in universal use, and
shown in Figs. 1750 and 1751, pp. 486 and 487, is also contained
in this patent. The mode of giving the end motion to the dis-
tributing-rollers on the inking- table, was simplified by Mr. Apple-
gath, who, in 1823, took a patent for effecting this object by
simply placing the rollers diagonally across the table instead of
at right angles to its motion. This combination of the inking—
table and diagonal distributing-rollers, is now in almost universal
use. It is applied to machines with one, two, or four cylinders,
and an equal number of feeders for printing newspapers, and it
is applied, together with the conveying-drums, to machines with
two cylinders and one feeder, for printing books.

30 parts lead, 30 of antimony, 30 of tin and 10 of
copper. In order to increase their strength the types
were not made so high as usual. A page of these
types being composed and well secured in an iron
frame, the face of the page was pressed into pure
lead by means of a fly press. The matrix for the
page thus obtained was next attached to the hammer
of a stamping press, on the bed of which was placed
in a paper frame a quantity of ordinary type metal in
a fused state, and when on the point of setting it was
rolled up into a mass and the matrix of the page being
brought down upon it, a sharp and well defined page
in relief was obtained. By this process of olz'eliage, as
it is called, the plates for Didot’s edition of upwards
of 200 volumes were obtained. Another but very
expensive method, invented by M. Herhan, was to
set up the page in letters or matrices of copper
sunk instead of being in relief. The page being
brought down upon type metal in a fused state, pro-
duced at once a page fit for printing. Various at-
tempts have also been made to produce casts by
pressing upon the composed type sheets of paper
with whiting or some other substance between them?
Bitumen, gutta percha, &c., have also been em-
ployed, the former substance answering well for
engravings.
Attempts have been made to abridge the labour of
composing by introducing the use of types bearing
whole words or syllables, under the name of logogrn-
play or logograjoliie printing. An edition of Ander-
son’s “ History of Commerce,” in A vols. l.tto, 1787-9,
and some other works have been printed in this way;
but the scheme adds to the complication of the case,
and produces diiiiculties in the way of spacing. There
are also other objections, and the plan has been aban-
cloned.

(2) At a meeting of the Royal Scottish Society of Arts, 28th
Feb. 185 3, Dr. Daniel Wilson exhibited one of the original plates of
the edition of Sallust published by Ged in the 18th century,
and interesting as the first specimens of the practical application
of the stereotyping process ever executed. He then detailed the
various efforts at further improvement on this process—including
those of Brunell, Allan, Sinclair, 8zc.; after which he described
and exhibited the new process introduced by him to the notice of
the Society, which consists in taking the casts of the types, not
in gypsum or stucco, but in blotting-paper, overlaid with a thin
layer of whiting, starch, and flour-paste, covered with a sheet of
tissue paper, and impressed on the types by means of heating it
with a fine brush. It is then dried on a hot" steam-chest, while
still adhering to the types; and by this means a matrix is pro-
duced, and the types are again ready for distribution to the com-
positors within one hour. The advantages of the new process
are—first, the greater certainty of the process; the new matrix
not being liable to warp or break, as the stucco is. Second, the
greater rapidity; the process being completed in one hour by it,
which could not be done in less than six by the other. Third,
the practicability of using the matrix in certain cases for casting
several plates; whereas the stucco mould is always destroyed in a
single casting. And, fourth, the much greater simplicity of the
apparatus required; which, added to the economy of time, and
the consequent diminution of the quantity of type required for
the compositors, give the important economic results which form
the great merit of the new plan. A mould was made, and a cast
taken, in presence of the meeting; and Dr. Wilson concluded by
remarking that he believed it was by the improvement and more
general application of such processes as this, that the great deside-
ratum of cheap literature was to be achieved, and not by diminish-
ing the profits of retail booksellers, as had recently been attempted.
PRINTING.
499
SECTION VIL—Pnrnrrive IN CoLouns AND
IN GoLn.
The early printers prided themselves not only upon
the accuracy of their proofs, but also upon the beauty
of their printing. Typography in superseding the
scribe retained for a time the illuminator, and after
the sheets were printed, it was not uncommon to
insert titles, initial letters, &c., in crimson, blue, and
gold. When the illuminator ceased to find profitable
employment, the printer endeavoured to imitate his
labours by the use of variously-coloured inks. Hence
arose that department of printing, named Oliromolg/py.
one of the simplest examples of which is the printing
in red of the reel leller (lays in almanacs, and of the
rubric in the Church of England Prayer Book. In
these as in all other cases of letter-press printing in
two colours, each form requires to be worked twice,
once for the black ink and once for the red. In
passing the sheets the first time through the press
the red matter is omitted, the exact space which it
fills being occupied by quadrats. In the second
working it is difiicult to preserve good register,
especially as in the cases cited, where so small a
portion of red is to be inserted into so large a body of
black. Hence it is now usual to print red letter
days in old English type in black, and the rubric in
Italics, also in black.
Coloured inks require careful preparation, and
before being used they must be worked up. with
varnish on a stone slab with a muller to the required
consistency. The ink is applied to the types with a
ball or a roller, the former being preferable. Suppose
for example a form consists of pica, small—pica, and
long-primer, each in a different colour. The prevail-
ing colour, suppose the pica, is first worked: all the
lines in pica are set up, and the other lines are filled
in with small pica and long-primer quadrats. When
the second set of lines is to be worked, its quadrats
are taken out and the proper letters inserted, while
the type of the first lines is removed and quadrats
substituted; a similar plan is adopted for the third
lines, and in making these changes the form must not
be disturbed in its place in the press, and in this
treble working of the sheet care must be ‘taken not to
disturb the points on the tympan. Nor is the paper
to be allowed to dry; otherwise it will shrink, and the
register cannot afterwards be obtained. If the
number cannot be worked off in one day, the paper
must be covered with a wet blanket and the edges
slightly sprinkled.
Great encouragement was given to printing in
colours by the contractors for the English State
lotteries, who, shortly before the abolition of this
enormous evil, issued vast numbers of ornamental
handbills for the purpose of putting off their schemes.
After this time ornamental printing fell greatly into dis-
use, until about the year 1832, when it was revived by
M. De la Rue’s patent for printing playing cards. This
led to great improvements in the composition and
mixing of coloured inks; the art was applied to the
printing of landscapes and figures, &c., in colours, and

it has now attained a degree of excellence surpassing
that of any former period. _
In printing in gold the type is composed and made
ready in the usual manner. The gold leaf is‘ made
to adhere to the paper by means of a varnish, composed
of raw or burnt umber mixed with printer’s varnish to
the same consistency as printer’s ink; this mixture
is then compounded with a considerable quantity of
gold size. The first mixture is necessary, as the
umber will not combine with the size. The type‘ is
rolled with this compound as in ordinary printing, and
the impression is taken on paper. Leaf gold is next
laid over it with a piece of wool, and pressed lightly
upon it. When the varnish is set the wool is rubbed
roughly over the printed part, the superfluous leaf is
removed, leaving the gold adhering to the varnish.
To obtain good results the type should be sharp and
the presswork good. Some years ago the “ Magna
Charta” was printed by Mr. Whittaker in letters of
gold with illuminations. The work was very superior,
but the method of working was kept secret, nor was
the method generally known until the publication of
the Jury Report, (Class xvii.) in which it is stated as
follows :-—“ The page is composed in movable type
in the usual way: a stereotype-plate is taken. A
piece of iron of the size of the page, about half an
inch in thickness, is made hot and placed on the table
of an ordinary typographical printing-press ; the stereo-
type plate is then placed on the iron plate, and gets
hot, and leaf gold of an extra thickness of the size of
the plate, is laid very carefully on the surface of the
plate: then the paper or vellum. is placed on the
tympan in the usual way, having been previously sifted
over with dried glare of egg, and rosin finely pul-
verized, which adheres to it in sufficient quantity; the
tympan is then turned down and the pull dwelt on.
The degree of heat must be ascertained by practice;
if the plate be too hot, the gold is dead and drossy; if
too cold then it appears bright but imperfect. This
process is similar to that now used by bookbinders
in block gilding with an arming-press.” [See BOOK-
:srnnrne, Fig. 175.]
For inferior gold printing bronze-powder is used.
[See Bnonzrna] The varnish is made much thicker
than for gold, and after the printing, the powder being
brushed over the card or paper, adheres to the printed
part, and the superfluous powder can afterwards be
readily brushed off. A very large trade is carried on
at Manchester in the printing of ornamental tickets
in gold and bronze, &c., for attaching to muslins and
calendered goods. [See CALEnnEnIne] But perhaps
the most remarkable instance of printing in gold, not
only on account of the great size of the work, but
from the short space of time allowed for it, was the
Sun newspaper, which contained an account of the
Coronation of Queen Victoria, and hence called the
“golden Coronation Sun.” The work was under-
taken by M. De La Rue. The papers were first
printed in varnish at the establishment of Messrs.
Clowes in Stamford-street, and then conveyed to
Messrs. De La Rue’s works in Bunhill Row, where
upwards of 100 persons were employed to rub on the
x x 2
500
PRINTING.
bronze powder. Upwards of 100,000 copies were
thus produced, 10,000 of which were in time for the
publication of the Sun on coronation day. In using
this powder great care should be taken to prevent it
from flying about, and being inhaled by the work-
people. For want of this precaution the persons
employed in the above extensive job' in rubbing on
the powder became afflicted with a very distressing
disease in which the hair became perfectly green.
_ The best kind of work in this style of printing is
by means of copper plates engraved deeper than usual,
instead ‘of letter—press. Sturz’s method was to mix
with printer’s weak burnt (oil a certain quantity of
gold or silver-bronze to the same consistency as that
of strong copper-plate ink, and filling the plate with
it to dab it in with the fingers. The plate being then
nicely cleaned off, first with a rag dipped in a very
weak solution of pearlash, and then with the palm of
the hand in the usual way, was passed with very
strong pressure through the press, and the impression
when dry was polished by passing it through the press
several times with the printed face against a highly
polished steel plate, by which a beautiful brightness
was imparted to the bronze. The copper-plate
printers, however, adopt the less expensive method
of first printing with a coloured ink ground with gold
size and oil, and then rubbing the bronze on the
paper just after it is printed.
M. De La Rue’s instructions for producing good
results by letter—press printing are as follows :—
“ Take the best printer’s varnish, grind it ‘to a thick
consistency with the best burnt sienna or brown
umber, and reduce this with De La Rue’s gold size
until it be of the thickness of thin treacle ; ink the
form in the usual manner, and when printed apply the
bronze by rubbing it gently over the article with
cotton wool. If leaf gold-or leaf metal is required it
must be laid on carefully, and when dry the sheets
should be wiped to clear them of the superfluous
bronze or metal. The gold printing is much improved
by its being passed over polished steel plates, between
powerful rollers.” Dutch gold cannot be used in this
style of printing.
SECTION VIIL—Oorrnn-rmrn AND LITHOGRAPHIC
rnrnrnve.—-Nunnnmne MACHINE.
Copper-plate printing is performed at what is called
a rolling press. It consists of two parts, the bod/J and
the carriage. The body is formed of 2 checks of
wood or iron placed vertically on a stand or foot
which supports the whole machine. From this foot
proceed a other vertical pieces joined by horizontal
pieces supporting a strong even plank of wood or
table, about 41% feet long, 2% feet broad, and about 1%
inch thick : within the checks are ‘2 rollers, the
upper of iron, the lower of wood. These rollers run
in the checks or gndgeons, formed by turning down
the ends of the rollers on 2 pieces of wood in the
form of half moons, lined with polished iron to assist
their motion’, One of the gudgeons of the upper
roller carries a cross consisting of two or more levers
crossing each other at right angles, by means of which

motion is given to the upper roller. In old presses
the space in the half moons left vacant by the
gudgeons is filled with paper, pasteboard, &c., in
order that they may be raised or lowered so as only
to leave between them the space required for the
carriage with the plate paper and blankets; but this
adjustment is now usually performed with a screw.
In the process of printing, the plate is raised to the
temperature of about 180°, by being placed on a grate
‘over a charcoal fire, or by the more preferable mode
now in use, on an iron box in which steam circulates.
This gets rid of the noxious fumes arising from the
burning charcoal, which formerly rendered copper-
plate printing so injurious to health. The man takes
up a'small quantity of ink on a rubber made of linen
rags strongly bound about each other, and dabs it
over the face of the heated plate. He next removes
the plate from the source of heat, takes ofi‘ some of
the superfluous ink with a piece of canvas, then with
the palm of the left hand, next with that of the right,
and to dry the hand and accelerate the wiping he
dabs his hand from time to time upon a surface of
whitening. The chief art of the printer consists in
properly wiping his plate, and he must manage so as
to remove every particle of ink or dirt from the

Fig. 1760.
COPPER-PLATE PRINTING.
smooth surface, and yet not disturb the ink in the
engraved parts. The plate is now deposited on the
plank of the press, and over the plate is laid the damped
paper which is to receive the impression, and over the
paper are placed 2 or 3 folds of flannel or blanket.
The arms of the cross are next pulled, and the plate
with its'furniture are thus passed between the rollers,
which by their strong but equable pressure, force the
moistened paper into the strokes of the engraving, by
which it absorbs the ink and retains the impression.
Some works' require to be passed a second time
through the press, as where the lines are deep and a
black impression is desired. - - -
The ink is composed of Frankfort black, which con-
sists of the carbon of peach and apricot stones, with
that of the bones of sheep or ivory produced by well
PRINTING.
501
burning: this is ground with well-boiled nut oil on
a marble slab. Three kinds of ink are usually em-
ployed, the thin, the ihioh and the strong ,- they differ
only in their degrees of cohesion: the strong is used
for the finer works. The stronger the ink the stronger
must be the pressure, and as this requires more
labour than a lighter pressure, the printer of course
prefers a thin ink. - - .
Some years ago Mr. Perkins contrived an improved
copper-plate press, in which a tympan was introduced 1
in order to save the expense of "making the plates or
blocks any larger than is necessary to'receive the
engraving. There are also other variations from the
common form, which we cannot detail for want of
space. I
The lithographic press resembles the copper-plate
press in several particulars, but differs from it by the
pressure being accompanied by a sort of scraping
movement. The first lithographic press consisted of
a hollow table for holding the stone ;* this, was inked
by means of rollers, and the paper being laid on it, a
tympan was brought down and a bar of wood pressed
firmly upon it: the stone was then by the action of
levers made to traverse from side to side beneath this
bar. In the'improved press (Taylor & Martineau’s)
there are two iron uprights rising from the bed or
table, and the stone is supported by a carriagemoving
on rollers along a small railway. The scraper or bar,
instead of being pressed down by a lever, is acted on
by a spring which keeps it in close contact with the
tympan. A cylinder’ worked by'a handle sets the
carriage in motion, and the stone is thus brought
under the action of the scraper or pressing bar. The
necessary adjustments are ‘made by means of regulat-
ing screws. ' -
An ingenious machine was invented by Mr. Bramah
for numbering bank notes. The notes are printed from
engraved steel plates, two notes on each plate, by
means of roller presses worked by steam: the date
and the signature are next printed in a different kind
of ink, by means of a small cylindrical printing
machine; the numbers are lastly added in a third
kind of ink, by means of a numbering machine.
Another machine, invented by Mr. Oldham, is now in
use, which our space will not allow us to describe; 1
but the principle of it will be understood from the
following brief notice of Mr. Bramah’s invention.
The number on each note is printed twice, first
over the words I Promise, and again over the word
Bearer. Any number being thus printed, the unit
figure changes to the next in order, then again to
the next, and so on until the change is required in
the ten’s place: the'tens in like manner change
in due order until we come to the hundreds, and
these change as required, and so on. Taking the
machine in its simplest form, as for a single note, it
consists of a solid base of mahogany, to which the
sides of the machine are firmly attached. These are

(1) This machine is a great improvement on Mr. Bramah’s. A
machine patented in March 1845 by Mr. Shaw, is fully described
in the Repertory of Patent Inventions: it is in great request as
a paying machine.

of iron and only one is seen in the figure. From one
side to the other of the machine are 3 axes,'a a’ oz, to
the last of which is attached the handle H, which is
raised and depressed by the operator: to this handle
is attached the platten or tympan '13. When the
handle is raised this plate may be opened, and the
note to be numbered is introduced and placed in- its





Fig. Herr.
proper situation by means of 2' guide pins ; the plate
is then shut and the note properly confined, there
being 2‘ holes in the plate to allow the-types contain-
ing the numbers to come in contact with the paper.
On the axis a’ are 5 brass circles of which only one is
seen in the figure: each of these has 11 teeth, in
which are cut notches to carry the digits 0; 1, 2 8 . .
. . . 9, and one blank: the other wheel on ‘the axis a
has also 11 teeth, so that moving one tooth on the
latter turns the other one tooth round. There are 3
wheels on the axis, 2 of which are in contact each
with one of the brass wheels on the 2 ends of the axis
a’, and the other is a centrallone'by which the motion
is communicated. When the‘ handle H is raised
nearly perpendicularly and stopped by the fixed stud
8 coming in contact with the back of the handle, the
tooth or claw will have passed the upper tooth of the
wheel a, which it does without resistance as it moves
freely on its joint; but in returning the handle to its
horizontal position, the claw having no- motion in the
opposite direction, catches the upper tooth and forces
it round the interval of one tooth, and this again
forces the wheel a’ also one tooth, and consequently
changes the llllIl'lb'GFOllB place, as from O to 1, or from
1 to 2, &c., the several types being arranged in order
round the wheel. Of the 5 circles on the axis a’
suppose the 41 right-hand ones to have their blank
teeth all up, and that the tooth l is upon the right-
hand wheel, and suppose the impression No. 1 made
at the two ends or sides of the notes by the two out-
side wheels, and that the wheel a is in contact with
these two outermost circles. Then the handle being
thrown back, the note removed, and another intro-
duced, the claw a will have passed the upper tooth of
the wheel a, and on returning it will catch and press
forward this wheel onetooth, and this again the wheel
on a’, bringing the digit 2 to the upper position ; the
impression being made the same process if repeated
will bring up No. 3, then No. a, and so on to No. 9.
Having run through the units it is necessary to bring
up No. 1 on the wheel into the ten’s place, which is
done by making 2 strokes with the handle without
, Printing; the axle "1 is now pushed on end by a
502
PRINTING.
proper nut so as to bring the wheel a in contact with
the next brass circle; then, the blank being already
up, the next stroke brings up the 0, making with the
standing digit 1 No. 10; the next stroke gives 11,
then 12, 13 . . . . . 19. The first wheel is now moved
on by hand until 2 is the uppermost type; then
similar steps being followed the Nos. 20, 21, &c., are
obtained and lastly 99 ; when the first wheel becomes
the place of hundreds, the second of tens and the
wheel a is again put on end to engage the third type
wheel, and so on to any extent up to 99,999, which
is of course the highest number attainable by 5 type
wheels. The operator in using the machine first inks
the types with a small printer’s ball.
SECTION IX.--PniNTINe ron run BLIND.
The attainments made by certain blind persons
prove that few intellectual pursuits are denied to
them; a long list of poets, musicians, literary men,
and mathematicians might be given in illustration of
the degree of eminence which has been attained by
this class of persons; yet notwithstanding the evi-
dence thus afforded that their condition is no insur-
mountable obstacle to the acquisition of knowledge,
there has been no general and systematic effort to
raise the intellectual standard of the blind.
One of the earliest and most important measures
for the instruction of the blind was the contrivance
of characters in relief, over which a sightless person
might pass his hands, and so ascertain by the form
and arrangement of the letters, the sense they were
intended to. convey. These characters were first
made in metal and in wood; they were frequently
movable, and resembled in form the Illyrian or
Sclavonian alphabet, it being thought that the square
form of such letters would make them easily obvious
to the touch. Large cushions on which characters
were figured with inverted needles were also brought
into use for the blind. But the discovery of em—
bossed typography, which was made in 1784:‘ by M.
Valentine I-Iaiiy of Paris, soon banished all former
methods, and allowed the blind to have the privilege
of printing books for themselves, and of reading them
when printed. The value of this invention would be
immense if anything like uniformity of system could
be insured, but unfortunately, almost every institu-
tion for the reception and education of blind persons,
has it own distinct modes of teaching, and in many
instances its own distinct alphabetical characters, so
that the pupil, be he ever so well taught in one insti-
tution, is in a great measure isolated from the pupils
in other institutions 5 and what is still worse, he is
shut out from their printed books, many of which
may not exist in the character with which he is
alone conversant.
The greatest kindness which could possibly be
shown to the blind, as it respects their intellectual
progress, would be for those inventors and heads of
institutions who are now pursuing separate and inde-
pendent paths, to meet together and consult on a
common alphabet, and a universal system of type-
graphy which should be adopted at all their establish-

ments, so that the printing-press of one establishment
should be a source of instruction not to the few who
use the same character, but to all who speak the same
language. Such a consultation, however, would only
be so far valuable, as it faithfully represented the feel-
ings and wants of the blind themselves. The best cha-
racter to be adopted, is not that which is the most
popular with the seeing public, or that which may be
the least troublesome to the teachers in the several
institutions, but that which the blind can understand t/ze
most readily by means (y t/zez'r fingers. An intelligent
observer of the proceedings in L’ Institution Nalz'enale
ales Jeunes Avenyles, in Paris, remarks, “In England
the blind are, I believe, required by; touch to read sym-
bols intended for the eyes, and which, because they are
perfectly well adapted for one sense, have not very
logically been deemed equally valid for another, the
two not having together an idea in common. For
instance, to the eye gifted with the power of looking
over, almost at a glance, a territory of many miles
extent, it is but little trouble to observe the difference
between the diphl-hongs 0e and ac, or between long-
tailed and short-tailed letters of equally complicated
forms. To the touch, however, which is stone-blind,
the operation is difficult, tedious, and after all, un-
necessary.” ‘
The method adopted at the above-named institu-
tion will be explained in due course, but we will first
give a brief notice of the invention and successive
improvements and variations of printing in relief.
The first idea of employing the fingers of the blind
in reading written language is said to have been
suggested to M. Haiiy, by observing that a celebrated
blind pianist, Mademoiselle Parodis, who visited Paris
in 1784‘, distinguished the keys of her instrument
by the touch, and also understood, by the same
means, some maps in relief which had been then re-
cently invented. The happy idea of printing written
characters in relief, simple, and yet of vast importance,
then occurred to M. IIaiiy, and he was fortunately
gifted with a degree of zeal and enthusiasm which
carried him successfully to the attainment of his object.
After numerous experiments with dilferent letters, to
ascertain which appeared the most readily to be under-
stood by the pupils, he fixed on a character nearly
approaching the ordinary Roman, or rather inclining
to the italic, and used letters from the upper and
lower case in the ordinary manner, the capitals taking
more of the script form than the small letters. He
then commenced teaching gratuitously a number of
blind children of the Philanthropic Society: his pro-
ceedings and experiments having been favourably
reported on by a committee of the Academy of
Sciences. He also wrote several works on the sub-
ject, the most celebrated of which2 was translated
into English by Dr. Blaeklock, the blind poet, and

(1) Sir F. Head's Faggot of French Sticks.
(2) “ Expose de difl‘érents inoyens verifies par l’expérience pour
Ics mettre en état de lire a l'aide du tact, d‘imprimer des livres
dens lcsquels ils puissent prendre des connaissanees de Iangues,
d’histoire, dc geographic, dc musique, etc.; d’exécuter difi‘érents
travaux relatifs aux Inétiers.”-—In1pri1né par lesEnfants Aveuglcs.
Paris, use.
PRINTING.
503
published with his poems in London, 1793. An ex-
amination of twenty-four of Haiiy’s pupils before the
royal family at Versailles in 17 86, brought credit and
fame to the teacher and his system, but he seems to
have erred in commencing his printing, &c. on too large
and expensive a scale, so that when inconveniences
were perceived in the first form of characters used, it
was not easy to abandon the defective alphabet on ac—
count of the bulky and costly works which existed in
that character. The want of power to remedy errors,
together with some want of judgment in his capacity
of Director of the “ Institution Royale ales Jezmes
Aveagles,” (such was the title of his establishment,)
gradually brought Haiiy into disrepute, and after
some years he retired on a pension, and his place was
supplied by Dr. Guillié, an active enterprising man,
who revived the printing, modified the letters, and
published a number of elementary works for the in-
struction of the blind. The idea of an elementary
volume, among the seeing public, is naturally that of
an inexpensive, and generally a small and portable
work ; but these elementary volumes for the blind, on
account of the great space occupied by the embossed
letters, were ponderous folios published at 50 francs
per volume. For a long time these constituted almost
the only literature for the blind, not only in France,
but in other countries. They included Greek, Latin,
English, Italian, and Spanish grammars, extracts from
poetical and prose writers, religious manuals, &c.
Besides these works, Guillié published, in 1819, an
historical notice of the mode of instructing blind chil-
dren, all in embossed typography: this, as well as the
foregoing, was however open to many of the same
objections as Haiiy’s first books, the characters not
being strongly enough marked to be read without
much difiiculty. Strangely enough, Haiiy’s name is
not mentioned in this so-called historical notice.
Previous to his retirement, M. Haiiy had been invited
to introduce his system in Berlin and St. Petersburg,
which he did, in 1806, with advantage no doubt to
the blind in those capitals, but with little pecuniary
benefit to himself. The amount of embossed printing
in Germany is however very small.
The difficulty experienced by the blind in reading
the alphabets invented by the sighted, appears
to have stimulated an ingenious blind person,
named Louis Braille, to devise a system better
adapted to the wants of his brethren. It is only
necessary to close the eyes, and pass the fingers
lightly over his alphabet, to be convinced that the
system of points or (lots, which he has chosen to indi-
cate the difierent letters, is readily appreciated by
the touch. To form the letters of the alphabet he
makes use of only six points, disposed in a variety of
ways. Of these he uses one point for letter a, two
for letter l, and so on, but arranged with reference to
a certain size of letter represented by a parallelogram
of three dots by two {5 , and shown in our diagram
Fig. 17 62, by the boundary lines of the perforations in
the brass guide. It will be understood that the small
circles represent raised dots forming each letter of
his alphabet.

This system has one grand advantage connected
with it, namely, that the blind are able to write
freely and rapidly by puncturing the letters on paper
wanna]
b c f g h
we, warms as
Fig. 1762. PUNCTURED ALPHABET, ron THE BLIND, BY
LOUIS BRAILLE.
with a style, and then (still better) to read their own
writing, by turning the paper and passing their
fingers over the burs which the style has raised.
Mr. John Bird, a blind gentleman and member of
the medical profession,1 who visited the continent
last summer, for the purpose of inspecting the various
institutions for the instruction of the blind, has
kindly permitted us to copy a writing-frame in his
possession, similar to those in use in three institu-
tions of France and in one of Brussels, where Braille’s
arbitrary type is adopted to the exclusion of all
others. By means of such writing apparatus each
pupil, during his residence in the institution, writes
a number of books, which he carries with him on
leaving. In this way he multiplies copies of valuable
works, and impresses deeply on his memory their
various contents. In fact, his writing is a kind of
printing, and in this sense we notice it. The writing—
frame before us is, we suppose, one of the more
elegant forms employed. It consists of three pieces,
—-j£rsl, a thin slab of highly-polished mahogany,
thirteen inches long by nine and a half inches broad,
on which is fixed a plate of zinc z, Fig. 17 63, closely
and sharply grooved; secondly, a double mahogany
folding frame, united by hinges lz/i, between which
the paper r is to be inserted; the under part of this
frame fits over the metal plate, and is flush with it,
while the upper part is furnished with fifteen holes
on each side of its length, for receiving, flzirrlly, a
brass guide 5 b, which, after the insertion of the
writing-paper in the frame, is placed across the page,
a brass peg at each extremity fitting into the cor-
responding hole in the mahogany frame. The brass
guide has two rows of open spaces, and each space

(1) Ere long Mr. Bird will probably give to the world the fruits
of his experience and the result of his travels in a comprehen-
sive work on the condition of the Blind.
504!
PRINTING.
,M
allows of the formation of one of Braille’s letters
within it. There are three dozen of these spaces in one
line, so that the writer accomplishes two lines con-
taining six dozen letters by puncturing the requisite
number of dots within each space. This being done,
he moves the brass guide one peg lower down, and
It I»
_—~-'\./-’__-'’ M "‘—-'-'.._._..
~ A“
‘i -\ M>

_v. ‘nu
~~ \
_
i=filfiiéiilir.‘gi a
rrnnnnnnnnnnnnnnnnrnnyfl
UUUUUU BUEEBMI
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~
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H DB DUDE UDHDUUUDD


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I




_9=.____
. l
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i l

,.___.-
M
l
/
.._______..__._________

M”
li—
-__\_,_“_~ - . _._
W" _
BRAILLE'S VVRITING-FRAME FOR THE ‘BLIND.
repeats the operation. In one page of the size of
the writing-frame, he has thus the power of form-
ing, without any assistance from others, 30 lines of
writing, composed of 1080 letters, all perfectly legi-
Fig. 1763.
p ble to himself
--
by turning the
i _' page. The style
a, by means of
.,\ which this is
accomplished, is
a rather blunt
steel point, fixed
in a small handle
of ebony. The
grooves in the
zinc plate guide
the writer in
puncturing the
dots in one or
more of the posi-
tions 1, 2, 3, 41, 5, 6, Fig. 1'7 641', according to the ar-
bitrary arrangement of each letter. The blind, in
making use of this frame, write, not as we do, from
left to right, but like the Orientals, from right to left.
On reversing the paper, it is evident that they must
read what they have written in the same direction as
the sighted. An educated blind person with this
writing-frame, and a good supply of paper in sheets
of the proper size, may be to a great extent inde—
pendent of the .world ; for he has the means of
putting down his own experiences, or of recording the
experience of others, in a form legible to himself and
r”
Fig. 1764. PORTION OF THE FRAME AND
nnnss GUIDE, on THE ACTUAL SIZE.
,t
l
___ __
.- r
_____'—“._________J_._"‘ i . i
. ,_____.____.-_...-_-_.
.____. . ,
__.___p__—-_—_- -...._ ‘
i‘. n
. - ~ A -._.- a...
__j_ ‘_. _ ___=1 .\ , ..
"."y'". ': ,.. ‘a :..'....-_~.J,M_
'-,~',Z~¢433 “->_:3'. 15311.15.‘ "1", 4<A%4-
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ll
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g

to all who have made themselves masters of the
system. He has also the power of copying any work
printed in embossed typography. Mr. Bird informs
us, that when the intelligent blind of Paris, or the
blind professors (ten in number), wish to possess a
work of repute which has not yet been printed in
raised characters, they engage M. Victor, an eminent
sighted assistant, to copy the work on thin plates of
brass, the indentions of which are afterwards filled
with cement, which gives sufficient strength and con—
sistency to the points to allow of as many as 100
copies being struck off by a press from this stereotyped
page. In Sir Francis Head’s work is a striking,
though too ludicrous account of the method of writing
which we have been describing 5—“ Not only are
M. Braille’s embossed symbols evidently better
adapted to the touch than the letters and figures
which have been so cleverly invented for the eye-
sight, but to the blind they possess an additional
superiority of inestimable value, namely, that they,
the blind, can not only read this type, but with
the greatest possible case make 2'25, and as I witnessed
this very interesting operation, I will endeavour
briefly to describe it. A blind boy was required to
write down before me, from the dictation of his blind
professor, a long sentence. With a common awl, not
only kept in line, but within narrow limits, by a
brass groove which the writer had the power to
lower at the termination of each line, the little fellow
very rapidly poked holes tallying with the letters he
wished to represent. There was no twisting of his
head sideways, no contortion of face, no lifting up of
his right heel, no screwing up of his mouth, no
turning his tongue from beneath the nose towards
one ear, and then towards the other, in sympathy
with the tails of crooked letters, which in great pain
and difliculty, in ordinary writing, the schoolboy may
be seen successively endeavouring to transcribe. On
the contrary, as the little fellow punched his holes, he
sat as upright as a cobbler hammering at the sole of
a shoe. On the completion of the last letter he
threw down his awl, and then like a young author
proudly correcting his press, with his fore-finger,
instead of his eyes,—which, poor fellow, looked like
a pair of plover’s eggs boiled hard,--he touched in
succession every letter, and all proving to be correct,
he stretched out his little hand and delivered to me
his paper. To test the practical utility of the opera—
tion, a blind boy was sent for from another room.
The embossed paper (for what was a hole on one side
was, of course, a little mountain on the other) was
put into his hands, and exactly as fast as his finger
could pass over the protuberances made by his com-
rade, he read aloud the awled sentence which I had
heard dictated. I may observe, that besides letters
and figures, notes of music are also done by the awl.”
Another ingenious blind Frenchman, M. Foucault,
has done much to facilitate the progress of the blind.
Among other inventions, he has produced the Printing
Key-Frame, a somewhat costly apparatus, sold at
800 francs, but which affords the means of printing
off, with considerable rapidity, whatever the blind
PRINTING.
505
person wishes to convey to paper. It does not
enable him to read what he has written; but M.
Foucault has invented reproducing machines, by which
sentences may be copied in raised typography. The
Printing Key-Frame was exhibited in Paris, at the
E'cposz'tz'on of 1849, and was rewarded with a gold
medal and a favourable mention in the Report of the
Central Jury. “The blind,” says the Report, “ who
make use of M. Foucault’s invention are placed in
more favourable circumstances than the clearsighted.
They are enabled to write without having ever
learned how to form a single letter. It suflices to
know how to read by the touch, to be capable of ex-
pressing their ideas in an eminently legible manner,
inasmuch as they are shaped in typographic cha-
racters. The following is the process employed to
obtain this curious result. All the letters of the
alphabet, executed in relief and of considerable di-
mensions, are fixed on the upper extremity of metallic
rods, made to slide longitudinally in proper con-
tiguous canals. They are placed on the same plane,
and in the form of a fan; each of them exhibits in
its lower part the same letter as on the upper part,
but of small size. It is a printing character; and
the mechanism is so disposed that all the letters con-
verge towards the same point, and on being succes—
sively pressed by the fingers, deliver their impressions
successively on the same spot. Meanwhile, the paper
changes its place in a certain fixed proportion with
the motion of the letters, and thus the printing is
delivered clean, well arranged, and well spaced. On
the termination of a line the paper changes place in
a direction perpendicular to the former, and the
operation is renewed.” The operation of this Print-
ing Key-Frame was. witnessed by thousands in the
Great Exhibition in Hyde Park, where it also gained
a prize medal. The inventor, M. Foucault, was him-
self the exhibitor, and formed an interesting specimen
of talent, perseverance, and ingenuity, under the
most discouraging circumstances. M. Foucault is a
pensioner at the Qzmzze Vingt, an establishment for
the blind in Paris; but by exerting his musical
talents, and by keeping a small shop, in which he is
assisted by his wife, he has earned the means of
pursuing, at his own expense, those experiments and
inventions by which he so zealously endeavours to
benefit the blind. During nearly the whole of his
three months’ stay in England, at the time of the
Great Exhibition, he was hearing his own expenses,
and diligently working away with his Printing Frame,
and explaining its use and mode of working to little
groups of persons in the Crystal Palace, who gathered
round him, often without any knowledge of the
language in which he so eloquently addressed them,
but from curiosity to see a blind person using
with much rapidity this novel kind of printing ma-
chine.
In 1826 Mr. James Gall, of Edinburgh, began to
study the various methods of teaching the blind, and to
make experiments, with various arbitrary and Roman
alphabets, in order that he might discover one suffi-
ciently simple for finger-reading. In September 18:27

he published the first book printed for the blind in the
English language.1 It consisted of only nine pages,
four of which were embossed in high relief from
wooden type. Mr. Gall next issued sheets printed
from metal type, and found that they were easily read
by the pupils of the Blind asylum. WVhen he had
perfected his alphabet to his own satisfaction, which
was not until the year 1829, he commenced printing
the Gospel by St. John. For this work he tried three
different founts of type, the Joanie-English, the douole-
pz'ca, and the great-primer, printing and cancelling
many sheets in each. The printing was finished in
1832, but the work was not published until 1834:,
when it appeared as a Mo volume, the price being at
first, to subscribers, 1!. 18., though it subsequently sold
for 6s. The shape of Gall’s alphabet is given below,
and although experience abundantly proved that its
angular character made it exceedingly easy to the
at<aereki
ikkmnorar
srvvwxvx
vaaeoo7aoo
Fig. 1765. GALL’S ALPHABET AND NUMERALS FOR THE BLIND.
pupils, yet there is no doubt but .that his system
would have gained in general popularity, if he had
from the first conformed it (as he afterwards felt bound
to do) more nearly to our common alphabet. His
mode of printing in relief was superior to all that had
been previously done, being clear, sharp, and perma-
nent ; and in many parts of his system there were
great improvements on Haiiy’s method, and added
facilities for the learner. Gall is therefore justly
regarded as the founder of the English school for the
blind. On the first introduction of relief printing in
England, it was thought that the fingers ‘of the learn-
ers, in constantly passing over the embossed letters,
would soon level the uneven surfaces. But Gall de-
clares that his relief letters may be rubbed upon a
hard table with the fingers for any length of time,
and with any degree of pressure and‘ speed, without
the slightest deterioration; or they may be violently
beaten on a board with the fleshy part of the closed
fist, and the relief will remain as perfect, and will
stand out as prominently as ever. Mr. Gall succes-
sively published the Epistle to the Ephesians, that to
the Philippians, the Gospel by St. Luke (printed for
the British and Foreign Bible Society, London,1838,)
the‘Acts of the Apostles, and a series of Tracts for
the Blind, price Gel. each, printed for the Religious
Tract Society. In most of those works he adopted
a modification of his alphabet, bringing it into greater
resemblance to the common alphabet, but using a rough

(1) “ A First Book for teaching the Art of Reading to the Blind;
with a short statement of the principles of the art of printing as
here applied to the sense of touch.” Edinburgh. Published by
James Gall.
506
PRINTING.
or serrated character, which instead of being a help
to the blind was positively a hindrance to the reading
of his works.
Intelligent and benevolent efforts to benefit the
blind were soon made in different parts of England,
but the question of the alphabet still remained a
stumbling-block. Various arbitrary methods were
invented, and the Society of Arts of Edinburgh gave
rise to no less than 19 new alphabets by its offer of
a gold medal value 20l. for the best communication
on a method of printing for the blind. Among
the various English alphabets for the use of the
blind, there is one of an ingenious kind invented
by Mr. Lucas, whose system, however, partakes
too much of the nature of short-hand. It has
been adopted and improved upon by the “London
Society for teaching the Blind to Read,” and is one of
the most popular of the arbitrary systems. There is
also an alphabet by Mr. W. Moon, master of the Blind
Asylum at Brighton, in which the common alphabet is
taken as the foundation, but is greatly simplified. This
is a very recent and meritorious effort to improve the
teaching of the blind. But there is yet another
alphabet, which is constructed on the same principle,
and bears a considerable resemblance to that of Louis
Braille; whether suggested by it, or an independent
invention, we are not informed. It is the “New
Embossed Alphabet for the Blind,” of Mr. G. A.
Hughes, himself blind, and conducting an institution
for the instruction of the blind in the Westminster
Bridge Road, London. Several machines were sent
to the Great Exhibition by Mr. Hughes—1. To enable
persons born blind to write in raised characters
without type. 2. To enable the blind to write in
skeleton Roman capitals, which can be read by them-
selves as well as by those gifted with sight. 3. To
facilitate the casting of accounts, and making general
arithmetical calculations by tangible characters. 41.
A machine to copy and emboss music on paper. Mr.
William Hughes, governor of the Blind Asylum of
Manchester, also exhibited a typographical or writing
machine for the blind, which was favourably noticed
in the Jury Report as being the most simple in its
operation of any in the Exhibition. It is a remark-
able circumstance, that the simple and highly useful
J/Vriting Frame of Louis Braille should have been
either absent from or overlooked in our Exhibition,
considering that its invention dates twelve years ago,
and that its merits are so well known in Paris. We
have searched the Catalogue and Jury Report in vain
to find some mention of it.
Time and experience can alone decide ,between the
claims of all these contending systems; but we shall
never make real progress until we give due pre-
cedence to the inventions and suggestions of the
educated blind themselves. They are the only per-
sons really qualified to decide as to what is the best
and easiest mode of instruction, and their judgment
should be received with all deference by those who
can never gain their experience without the endur-
ance of their calamity.
While many difficulties have interfered ‘with the

progress of the various institutions for the blind in
this country, better success has attended the pro-
ceedings at Boston in the United States. This case
is thus described in the Jury Report -.—“ In 1838,
the Perkins Institution for the Blind was established
at Boston, and Dr. S. G. Howe, a gentleman dis-
tinguished through a long series of years for his
philanthropic glabours, was placed at its head. As
Gall ihad done, Dr. Howe took Haiiy’s invention as
the basis of his system, and soon made those im-
provements and modifications which have rendered
the Boston press so famous. He adopted the common
Roman letter of the lower-case. His first aim was
to compress the letter into a comparatively compact
and cheap form. This be accomplished by cutting off
all thej flourishes and points about the letters, and
reducing them to the minimum size and elevation
which could be distinguished by the generality of the
blind. He so managed the letters that they occupied
but a little more than one space and a half instead of
three. A few of the circular letters were modified
into angular shapes, yet preserving the original forms
sufficiently to be read by all. So great was the reduc-
tion that the entire New Testament, which, according
to Haiiy’s type, would have filled 9 volumes and cost
20L, could be printed in 2 volumes for 16s. Early in
the summer of 18341 he published the Acts of the
Apostles. Indeed, such rapid progress did he make
in his enterprise, that by the end of 1835 be printed
in relief the whole of the New Testament for the first
time in any language, in A handsome small étto.
volumes, comprising 624; pages, for A dollars. These
were published all together in 1836. The alphabet,
thus contrived by Dr. Howe in 1833, it appears, has
never since been changed. It was immediately adopted,
and subsequently became extensively and almost ex-
clusively used by the seven principal institutions
throughout the country. It is now the only system
taught or tolerated in the United States, and requires
only to be better known in Great Britain and else-
where to be appreciated. In America seventeen of
the States have made provision for the education of
the blind, and as universal education is the policy of
the country, as well as its proudest boast, these books
for the blind soon became in great demand. Dr.
Howe, some time since, proposed a library for the
blind, and with a view of increasing the number of
books as rapidly as possible, arrangements have been
made between the several institutions and presses to
exchange books with each other, and not to print any
work already belonging to the library for the blind.”
Similar care bestowed on the several institutions of
this country by some powerful and influential mind,
and a similar disposition among the managers of the
different establishments to establish harmony of action,
would be of immense advantage to the blind. Almost
simultaneously with the Boston institution, another was
founded in Philadelphia. It appears that their presses
and systems, of typography were established without
being apprised of the efforts of each other, conse-
quently there were diversities in the plan which will
1 probably disappear as time goes on. The Philadelphia
PRINTING.
507
press produced portions of the New Testament, and
several religious and other works, but it has now
ceased to act; and, when revived, it is more than pro-
bable that it will act in complete conformity with the
Boston press, so that there may be entire unanimity
in American institutions for the blind.
Printing for the blind has been carried on exten-
sively in Glasgow, the character used being the com-
mon Roman letter deprived of the small strokes at
the extremities. The main difi'erence between the
Glasgow and Boston alphabets is, that one is in the
upper and the other in the lower case. This difference
is not suflicient to prevent an interchange of books,
which has been carried on to the advantage of both
parties. Mr. Alston of Glasgow was the first to print
the whole Bible for the blind, which he did in 19
volumes. Since his death in 18416, the Glasgow press
has been comparatively inactive. Great Britain has
many distinct systems of typography for the blind at
the present day, and therefore many distinct sources
of embarrassment to the unfortunate individuals who
may be desirous of learning the art of finger-reading.
The Jury Report strongly urges the speedy adop-
tion of one system throughout the country, giving
a decided opinion in favour of Howe’s typography; and
it is the duty of all who wield the pen to represent
the injustice done to the blind by the present divi-
sions, and the imperative call to a more humane and
unanimous course of action. Yet our own convic-
tions incline to those systems which the blind them-
selves prefer, rather than to any, however popular,
which are invented by the sighted. Therefore we
would gladly see greater use made in this country of
the plan invented by the blind G. A. Hughes, or that of
the blind Louis Braille, which Sir F. Head, Mr. Bird,
and others, have seen in such successful operation in
Paris.
Sncrron X.—-—GALVANOPLASTIC AND OTHER Forums
or‘ PRINTING.
' The Great Exhibition brought into notice some
new forms of printing, some of which were of a re-
markable character. The following notices of them
are chiefly derived from the Jury Report :—
By means of a galvanoplastic process fossil fishes
have been reproduced upon paper with the exactness
of nature. Successive layers of gutta percha are
applied to the stone containing the fish, and a mould
is obtained, which being submitted to the action of‘
a voltaic battery, is quickly covered with coatings of
copper, forming a plate upon which all the markings
of the fish are reproduced in relief, and which when
printed at the typographic press give aresnlt upon the
paper identical with the object.
The Imperial PrintinD-ofiice of Austria, which ex-
hibited these results, also produced some remarkable
effects of yalvmzogmplzy. A plate of silvered copper
is covered by an artist with different coats of a paint
composed of an oxide, such as that of iron, burnt
terra sienna, or black-lead ground with linseed oil.
The substance of these coats is thin or thick, accord-
ing to the intensity of the lights and shades in the

’,picture. The plate is then submitted to the action
of the galvanic battery, from which another plate is
obtained reproducing an intaglio copy with all the
unevenness of the original painting. This is an actual
copper-plate resembling an aquatint, and obtained
without the assistance of the engraver.‘
The process of gaZvanoyZ‘I/pky, invented in England,
and patented by Mr. Palmer, is not less interesting.
A drawing is etched upon a plate of zinc coated with
varnish; and upon this a coat of ink is spread by
means of a small composition-roller. The ink is de-
posited only on those parts where the varnish has not
been broken through by the etching-needle, the sunken
portion of the engraving being left free. When the
first layer is dry, a second is applied, then a third, and
so on, until the original hollows are considered to be
deep enough. The plate, thus prepared, is placed in
the galvanic-battery, and another plate is thereby
produced, on which all the hollows of the engraving
are reproduced in relief. This relief is more or less
raised according to the number and thickness of the
coats of ink successively applied.
In order to obtain casts in relief from an engraving,
the process of clwmz'iypy may-be adopted. A polished
zinc plate is covered with an etching ground; the
design is etched with a point, and bitten in with dilute
aquafortis: the etching ground is then removed and
the acid well cleaned off, by first washing the hollows
of the engraving with olive-oil, then with water, and
afterwards wiping clean. Filings of fusible metal
are then placed on the plate, and the latter is heated
by means of a spirit-lamp until the fusible metal has
filled up all the engraving: when cold, the surface of
the fusible metal is scraped down to the level of the
zinc plate, leaving only that portion of it which en-
tered the hollow parts of the engraving. The plate of
zinc is next submitted to the action of a weak solution
of muriatic acid ; the zinc alone will be attacked, and
the fusible metal which was in the hollows of the en-
graving is now left in relief, and may be printed from
at the typographic press.
The process of pmzez'conogmp/zy, invented by M.
Gillot of Paris, has for its object the reproduction of
any lithographic, autographic, or typographic proof,
any drawing with crayon or stump, or any engraving
upon wood or copper. This comprehensive object
gives the name to the process from m'io'av eZKdz/a
ypa’rrpew, “ to delineate all kinds of images.” A plate
of zinc is to be well polished with pumice-stone, and
on this the artist executes the required design with
lithographic crayon or ink, or the impressions from
lithography, wood-engraving, or copper-plates, may
be transferred to the zinc-plate, as in the process of
maszfaz‘z'c printing} The surface is then inked over
(1) Anastatz'c printing (from duIa-mo-Gar, stand 2147,) is performed
as follows z—Immerse in, or moisten with, dilute nitric acid, the
print or sheet of letter-press, 850. which is to be transferred; the
acid softens the ink, and on passing the print in contact with the
zinc-plate through a roller-press, the zinc-plate will take a. re-
versed fac-simile of the print; and on passing an inked roller over
the zinc-plate the ink will adhere only to the slightly-raised lines
of the reversed impression, and on passing this with a sheet of
white moistened paper through the press, a perfect fac-simile of
the original print is produced.

508
PRUSSIAN BLUE.
with a roller so as to increase the thickness of the
ink, which is afterwards consolidated by dusting finely-
powdered rosin over the plate, by means of a pad of
wadding: the rosin adheres only to the ink, and is
readily removed from the other parts of the plate.
Afterwards, in order to obtain a relief-‘block, the plate
is placed on the bottom of a shallow trough, contain-
ing very dilute sulphuric or hydrochloric acid. By
means of a rocking motion given to the box, which
for that purpose is fastened to an axis, the acid is
caused to pass slowly and continuously to and fro
over the surface of the plate. After the lapse of half
an hour, if it be a crayon drawing, the etching is
completed, and a relief-block is obtained, in which it
is only necessary to remove the large whites by saw-
piercing. But should the plate contain written matter,
or many very fine lines, it must be withdrawn from
time to time, and the surface again inked with litho-
graphic ink, and dusted with powdered rosin, so that
the edges may be protected as much as possible from
the undermining action of the acid: these operations
must be repeated until the necessary depth is obtained.
Transfers may be made from very old impressions of
wood-engravings by sponging them several times at
the back with acidulated water, and then operating as
is usual with lithographic transfers.
PRISM. See Lren'r.
PBUSS'IAN BLUE. This'pigment was dis-
covered in 1710, by Diesbach, a colour-maker at
Berlin: the method of preparing it was first de-
scribed by Woodward in the Philosophical Trans-
actions for 1724:. It is a compound of iron and
cyanogen, and is known to the chemist as the sesqui-
jerroeyanide ry" iron. It is prepared by precipitating
solutions of peroxide of iron by means of fierro-
cyanide rfpozfassianz. The first step, therefore, in the
manufacture of Prussian blue, is the preparation of
ferrocyanide of potassium, or prassiate of potash, as
it is more commonly termed. For which purpose
certain animal matters are employed, as sources of
cyanogen (Oz N or Cy. See GYANOGEN), such as chips
of horns, hoofs, woollen rags, greases, or the refuse
of tallow-melters, consisting chiefly of cellular mem-
brane, from which the fat has been expressed, dried
blood, hair, skin, 850. These are triturated with
potash, or pearlash, and then burnt or fused at a high
temperature in an iron pot. The resulting mass,
called pra'ssiaz‘e ca/ce, is a dark grey mass, which, on
being lixiviated with hot water, yields what was
formerly termed Zia'ivianz sangainz's, or blood lye .-
this, on being evaporated, yields lemon-coloured
crystals of prussiate of potash. The first crop is
very impure ; it is re-dissolved, and the second crys-
tallization is allowed to go on for a fortnight, without
disturbing the contents of the coolers. In the form-
ation of this salt, the essential ingredients are animal
matter, rich in nitrogen and metallic iron, or its sul-
phuret. The iron is usually obtained at the expense
of the pot in which the process is conducted, or iron
filings are added in the charge. The sulphuret of
iron is formed first by the decomposition of the sul-
phate of potash contained in the impure potash, or I

pearlash, employed. The presence of charcoal at a‘
red heat converts the sulphate of potash into bi-
sulphuret of potassium; and this is further decom-
posed by the iron with which the sulphur unites. It
is important to exclude the air as much as possible, in
order to prevent the oxidation and destruction of the
cyanide of potassium as it is formed. On treating
the mass with hot water, the cyanide of potassium is
dissolved out; and this is quickly converted into
ferrocyanide, by means of the oxide or sulphuret of
non.
Ferrocyanide of potassium (2K Cfy + 3110, or
2K, 06 N3 Fe + 3110) crystallizes in large transpa-
rent yellow crystals, derived from the octahedron
with a square base. They readily cleave in a direction
parallel to the base of the octahedron, and are tough
and diflicult to powder. They are soluble in 41 parts
of cold, and in 2 of boiling water; but are insoluble
in alcohol. They have a mild saline taste, and are
permanent in the air. By exposure to a gentle heat,
this salt loses its colour, parts with 3 equivalents of
water, and becomes anhydrous. At a high tempera-
ture it yields cyanide of potassium, carburet of iron,
and various gaseous products. If air be present, the
cyanide of potassium becomes cyanate of potash.
This salt is an excellent reagent for distinguishing
the metals from each other. -All the precipitates
thrown down by this salt are double compounds of
cyanide of iron with cyanide of the metal thrown
down. The precipitate from sulphate of copper is of
a fine brown colour, and has been used as a pigment;
but, being somewhat transparent, it does not cover
well. The precipitate from the peroxide salts of iron
is of a very intense blue : this is Prussian blne, or, as
it is named in some parts of the continent, Paris
Mae. There is some disagreement among chemists
as to the exact composition of this precipitate. The
fact is, that several distinct deep blue compounds are
formed under different circumstances which have been
regarded as identical. According to Berzelius, ordi-
nary Prussian blue consists of C18 N9 F67 or 30fy
+ étFe, and is best prepared by adding pernitrate of
iron to a solution of prussiate of potash, the latter
slightly in excess. A bulky and intensely blue pre-
cipitate is formed, which, on being washed and dried
at a gentle heat, shrinks considerably. When dry, it
is hard and brittle, and resembles the best indigo:
the fresh fractured surface has a fine copper-red
lustre. Prussian blue is insoluble in water and dilute
acids, except oxalic acid, a solution- of which dissolves
it. Strong sulphuric acid converts it into a white
pasty mass, which resumes its blue colour on the
addition of water. The colour is instantly destroyed
by alkalies, which dissolve out a ferrocyanide, and
leave oxide of iron; The colour is also bleached by
the direct rays of the sun, but it returns when the
pigment is left in the dark. When heated in the air,
Prussian blue burns like tinder, leaving a residue of
peroxide of iron 3 but when heated in a close vessel,
it disengages water, cyanide of ammonium, and car-
bonate of ammonia, and leaves carburet of iron.
Prussian blue is a beautiful pigment, both as an oil
PRUSSIAN BLUE.
509
and water colour, but it is not very permanent. It is
largely used in the decorative arts ; also as a dye-stuff
and in calico-printing. It is used for some of the
varieties of stone-bias, for concealing the yellow
colour of linen, and it is also used in starch. It is
employed in certain writing-fluids, or blue inks, oxalic
acid being the solvent. The Prussian-blue of com-
merceis very impure :_ it contains alumina, and other
substances, which injure the brilliancy of the colour.
The Prussian-blue precipitate is thus formed from
the solution of ferrocyanide of potassium, by means
of a salt of iron containing no protoxide. If the iron
be but partially peroxidized, the precipitate will at
first be of a pale blue, which becomes a dark blue by
exposure to the air. This pale blue precipitate con-
sists of a mixture of prussiate of the protoxide and
prussiate of the peroxide of iron. If exposed to air,
in a moist state, it becomes of a beautiful dark blue
colour; but this new combination, formed by the ab-
sorption of oxygen, is essentially different from that
produced by the precipitation, by means of the per-
oxide of iron, since it contains an excess of peroxide,
in addition to the usual 2 cyanides of iron: hence
it is called basic Prussian Mac ; and, from the property
of its being soluble in water, soiaoie Prussian Mae.
In the manufacture of this pigment, on a large
scale, the first process is the production of the prus-
siate of potash. For this purpose the raw materials
require some previous preparation. If blood can be
procured in sufficient abundance, it is to be pre-
ferred: it is evaporated to dryness, powdered and
sifted. The other materials, such as parings of hoofs,
horns, hides, Woollen~rags, &c., are thoroughly dried
and then used, or they are calcined in cast—iron cylin-
ders. The latter plan allows the ammoniacal products
to be collected, and to a certain extent prevents the
escape of nauseous vapours, which cause this manu-
facture to be a nuisance to the whole neighbourhood.
But on the other hand, it is stated that the prussiate
is more easily produced when the animal substances
are employed in the uncalcined state. 8 lbs. of horn
or hoofs, and 10 lbs. of dry blood, yield about 1 lb. of
charcoal. This is mixed with good pearlash, either
dry or by soaking it in a strong solution of the alkali.
The proportions are about 1 part of carbonate of


Fig. 1766.
potash, 1% or 2 of charcoal, or about 8 parts of hard
uncarbonized animal matter. The calcining-pot,
shown in section in the furnace, Fig. 17 66, is oval in
form, with a narrow neck, to allow the mouth to be

closed with a small plate. It is of cast-iron, about
2 inches thick in the belly. It is built in the furnace
in a sloping direction, and is supported on the back
wall by a projecting knob, while it is steadied near
the month by ‘2 arms built into the brick-work.
The pot occupies the greater part of the furnace, in
order that the flame may play closely upon it. The
fireplace is situated behind, in order to prevent the
workmen from being inconvenienced by the heat. A
stone slab is placed before the mouth, to prevent loss
of materials in discharging the pot.‘ If fresh animal
matter is used in the charge, the pot is left open at
the mouth, in order to allow of the stirring of the
contents with an iron scoop, and of the introduction
of fresh materials, as the swelling subsides. In the
course of 5 or 6 hours nauseous vapours cease to
be evolved, the flame becomes smaller and brighter,
and a smell of ammonia appears. At this stage no
more fresh materials are added, but the heat is in-
creased, and the mouth of the pot closed, or only
opened every half-hour for the purpose of stirring up
the charge with the iron rabble. When flame ceases
to be given off from the mixture, the process is com-
pleted. When the animal matter has been previously
carbonized, the pot is closed as soon as the charge is
well ignited; and it is only opened for a few seconds
every quarter of an hour, for the purpose of stirring.
For some time a body of flame bursts out every time
the cover is removed; but when this ceases, the mix
ture softens down into a paste. The flame gradually
becomes less and less as before, and when it ceases
the process is complete. The plan introduced at
Glasgow, in 1821i, by the late Charles Mackintosh, of
agitating the fluxed mass by machinery in closed pots,
has greatly increased the yield of prussiate from the
same quantity of animal matter. When the charge
consists of about 50 lbs. of charcoal, and the same
weight of good pearlash, the operation lasts about
12 hours with a cold pot; but only 7 or 8 if
a second charge be added as soon as the first is
removed. The fused mass is removed with an iron
scoop, and cooled in small portions as quickly as pos-
sible. It is‘next put into water, a moderate heat is
applied, aad the solution is filtered through cloths.
The charcoal left in the filter, mixed with fresh
animal charcoal, is used in the next charge.
Most of the iron in the ferrocyanide is obtained
from the pot in which the operation is conducted.
When this wears into holes it is taken out, patched
with iron cement, and built in again with the sound
side undermost. If iron filings (about 130 or 150 by
weight of the potash) be mixed with the charge, the
corrosion of the pot is not so rapid.
The solution is not a pure ferrocyanide : a portion
of the materials not having absorbed a sufficient
proportion of iron, forms only cyanide of potassium;
it is also contaminated with carbonate, sulphate, and
phosphate of potash, phosphate of lime, &c., from
the impure potash and the incinerated animal sub-
stances. Before evaporating the lye a solution of
protosulphate of iron is added sufficicnt to re-dissolve
the white precipitate of cyanide of iron, which first

510
PRUSSIAN BLUE.
falls, and so convert the cyanide of potassium which
is present in the liquor, into ferrocyanide of potassium.
The solution is evaporated and the crystals removed:
the mother liquor is also evaporated, and yields a
somewhat inferior ferrocyanide.
According to Dumas1 the following results ought
to be obtained from the calcination of 100 parts horn
clippings and the addition of 40 parts of alkali to the
resulting animal charcoal :—
Solution of carbonate
100 parts of ammonia (15° B) 50
horn clippings 16
Animal Charcoal .... .. 30—30} 46.80 offused prus-
Alkali 40 siate cake = 7.02
prussiate of potash.
In order to precipitate the Prussian blue from the
solution of prussiate of potash, green sulphate of
iron is employed on account of its cheapness, although
the red sulphate, nitrate or muriate of iron, aifords a
richer blue pigment. The salt of iron employed
must be free from copper, or the precipitate will have
a dirty brownish hue. “ The green sulphate of iron,”
says Dr. Ure, “ is the most advantageous precipitant,
on account of its affording protoxide to convert into
ferrocyanide any cyanide of potassium that may
happen to be presentin the uncrystallized lixivium.
The carbonate of potash in the lixivium might be
saturated with sulphuric acid before adding the
solution of sulphate of iron; but it is more com-
monly done by adding a certain portion of alum, in
which case alumina falls along with the prussian
blue, and though it renders it somewhat paler, yet
it proportionably increases its weight; whilst the
acid of the alum saturates the carbonate of potash
and prevents it throwing down iron-oxide to degrade
by its brown-red tint the tone of the blue. For
every pound of pearlash used in the calcination, from
2 to 8 lbs. of alum are employed in the precipitation.
When a rich blue is wished for, the free alkali in the
prussian lye may be partly saturated with sulphuric
acid before adding the mingled solutions of copperas
and alum. One part of the sulphate of iron is
generally allowed for 15 or 20 parts of dried blood,
and 2 or 3 of horn shavings or hoofs. But the
proportions will depend very much upon the mani-
pulations, which if skilfully conducted, will produce
more of the cyanides of iron, and require more
copperas to neutralize them. The mixed solutions
of alum and copperas should be progressively added
to the lye as long as they produce any precipitate.
This is not at first a fine blue, but a greenish grey,
in consequence of the admixture of some white
cyanide of iron: it becomes gradually blue by the
absorption of oxygen from the air, which is favoured
by agitation of the liquor. Whenever the colour
seems to be as beautiful as it is likely to become, the
liquor is to be run off by a spigot or cock from the
bottom of the precipitation vats, into fiat cisterns to
settle. The clear supernatant fluid, which is chiefly
a solution of sulphate of potash, is then drawn off

by a syphon; more water is run on with agitation to
wash it, which after settling is drawn off again, and
whenever the washings become tasteless the sediment
is thrown upon filter sieves and exposed to dry, first
in the air of a stove, but finally upon slabs of chalk
or Paris plaster. But for several purposes, Prussian
blue may be best employed in the fresh pasty state,
as it then spreads more evenly over paper and
other surfaces. A good article is known by the
following tests: it feels light in the hand, adheres to
the tongue, has a dark lively blue colour, and gives
a smooth deep trace; it should not effervesce with
acids, as when adulterated with chalk, nor become
pasty with boiling water, as when adulterated with
starch.”2
By passing chlorine into a somewhat dilute and
cold solution of ferrocyanide of potassium, the liquid
acquires a. deep reddish green colour, and no longer
precipitates a salt of the peroxide of iron. By
evaporation, prismatic or tabular crystals of a bean-
tiful ruby red tint are produced: they are permanent
in the air, and soluble in It parts of water, forming
a dark greenish solution. This salt is named red
prussiate of poms/z, or more properly ferrz'dq/mzz'de
cy‘" potassium K3, Cys F62, and is formed by the ab-
straction of an equivalent of potassium from 2
equivalents of the yellow salt. The red salt is used
in calico-printing, and both salts are “ employed in
de Zaz'ne printing as well as in dyeing wool; the blue
from the red prussiate being found more durable
when fixed by peroxide of tin. The red salt is also
mixed with wood colours to oxidize them, or produce
the great depth and beauty of colour which long
exposure to air without light, otherwise induces in
the dye woods.”--Jury Report, Class II.
The colour known in commerce as Tmvzéull’s blue,
is the precipitate formed by adding a solution of
ferridcyanide of potassium to a protosalt of iron:
it is produced by the substitution of 3 atoms of iron
for the 3 of potassium. Its colour is a little brighter
than ordinary Prussian blue. It is prepared in the
arts by adding to the protosulphate of iron a mixture
of yellow prussiate of potash and hypochlorite of
soda.
Patents have been taken out at various times for
improved, or supposed improved, methods of manu-
facturing prussiate of potash. The following details
of a patent taken out in January 184:0, in the name
of Mr. Berry, involve chemical details of great
interest. The specification states that the common
process entails the loss of a considerable quantity of
nitrogen, either in the free state or under the form
of carbonate of ammonia. To avoid this loss, the
primary matters are treated difi'erently, so as to
collect the nitrogen which escapes during the dis—
tillation, and to cause it to enter into combination
with carbon, iron, and potassium. Instead of col-
lecting the carbonate of ammonia in or by an
absorbent medium, it is made to pass through a
quantity of charcoal, iron, and potash placed in


( 1) (Zhimie Appliquée. See also Gmelin’s Handbook of (‘hemis-
try, vol. vii. forming vol. i. of the Organic Chemistry. Cavendish
Society’s Translation, 1852.

(2) Dictionary of Arts, Manufactures, 8:0. Article Paussrarz
I BLUE. See also Dumas, Chimie Appliquée, tom. 7'’, pp. 652-662.
PRUSS‘IA'N“ BLUE.
511
an ‘iron tube and maintained at a red heat. The
carbon on the one part decomposes the carbonate
of ammonia and forms bicarburetted hydrogen, and
at the same time gives up part of it to the nitrogen,
which proceeds from the decomposed ammonia and
thereby forms cyanogen, which in its turn combin—
ing with the reduced ~potash forms ferrocyanide of
potassium or prussiate of potash. To obtain the
most complete reaction, the ingredients which con-
stitute the decomposing compound must be divided
or reduced. This may be done by one of the follow-
ing methods z—Fz'rszf met/rod. Reduce the charcoal
to fragments of about the size of a nut or walnut;
then dissolve the potash (the carbonate or nitrate) in
urine if a sufficient quantity can be readily obtained,
otherwise in common water. The iron is to be
rendered soluble by the addition of nitric or acetic
acid. The solution of potash and nitre is next to be
poured on the charcoal; the saline lye will soon be
absorbed; next pour in the solution of iron, stir the
mixture, and evaporate the water without calcining
the compound. The compound, when dry, is to be
again pulverised and introduced into iron tubes. The
proportions which have been found to give good re—
sults in this process are, ordinary potash, 30 parts;
saltpetre, lO ; acetate, or nitrate of iron, 15; coke,
or ordinary charcoal, 415 to 55; dried blood, 50.
Second met/rod. This consists in the substitution of a
mechanical for a chemical division. The potash, nitre,
and charcoal are introduced into a barrel'with iron
filings. Some cannon balls are to be put into the
barrel, which, being made to revolve on an axis, the
balls will grind the compound and reduce it to small
fragments mixed together. The compound is either
transferred to the cast-iron pipes, or kept for use in
a dry place. The proportions which have been found
to answer in this process are,. 20 parts of ordinary
potash; 10 of saltpetre ; 20 of iron filings; A5 to 55
of coke or charcoal; 50 of dried blood. The compound
ingredients prepared by either method are introduced,
when perfectly dry, into a series of pipes connected
together, and contained in a furnace similar to that
used for heating the retorts in the manufacture of
gas. [See Gas] But instead of placing the pipes
in a horizontal position, which renders it difficult to
introduce and draw out the materials, they may be
placed vertically, in which case the dry compound is
not completely pulverised, but left in lumps in order
to allow the gases to circulate more readily. The
animal matter is placed in a separate compartment,
and in a cast—iron retort connected with the vertical
pipes. This retort is furnished with a safety-valve.
The pipes must be raised to a red heat before the
retort is heated, in order that, from the commence-
ment of the operation, the decomposition of the gases
may take place. The gas evolved by the decomposi—
tion is inflammable when issuing from the pipes, and
the colour of the flame indicates the process of the
operation. The colour difiers generally but little from
that of the heated cast-iron pipes in the furnace.
When this colour approaches to pink, the reaction is
almost complete, so that very little, if any, ammonia


has escaped decomposition. When the jet of gas
becomes smaller and clearer, and there is a good fire
under the retort, the operation is nearly terminated ;
the animal matter is reduced into nitrogenated char-
coal, which is commonly used for the manufacture of
prussiate of potash, and which is still to be employed
in the same manner and treated as usual. On the
other hand, the nitrogen, ammonia, and other gases,
by combining with the decomposing substances con-
tained in the pipes, have been transformed into prus-
siate of potash. The charge must then be directly
removed from the pipes, and being at a red heat, it
should be at once thrown into water in order to ex—
tinguish it rapidly, the whole being well stirred and
allowed to settle. The clear liquor is then to be
drawn off, and this forms the strongest solution:
warm water is then to be poured on the carbonaceous
residuum, and being well stirred and allowed to settle,
the liquid is drawn off. This operation is continued
until the residuum is exhausted. The strong solutions
are to be evaporated and crystallized, and the pruse
siate is extracted according to the old process. The
solutions which will not crystallize contain carbonate
of potash: this is extracted therefrom to be employed
again. The same is done with reference to the resi-
duum of charcoal and iron. All this residuum is car-
ried to the following operation, to which is added the
animal charcoal furnished by the first operation, by
the calcination of animal matter. Besides this animal
charcoal, a proper quantity of fresh charcoal is added
in order to preserve, as far as possible, the same
proportions in the decomposing mixture. After some
operations, the animal charcoal may be found com-
pletely deprived of nitrogen: a portion of it is in such
case laid aside, and a proper quantity of fresh animal
charcoal substituted. Thus, after a short time, the
coke or vegetable charcoal first employed, is com-
pletely set aside, the whole operation being effected
by two kinds of animal charcoal, of which one is
almost deprived of nitrogen, and the other contains
a large quantity of the same.
The apparatus in which the above process is con-
ducted consists of a furnace, of which a horizontal
section is shown in Fig. 1678, constructed for the
reception of A elliptical pipes, r, r‘, 1? 2, r 3. The

i
an.
tr": .. .
Zita???
wag?‘
.
. f
. '" \ ‘
:.. .r _.. 2;‘ ."...-..l'...‘ Ifllwul’l’luuwmlul
l
5
III!‘ w
. A, .. v ,r. .
‘- .iilizh’if'eérmiel ‘
-. as :1 "-.,-.-".ra»gmat;s"
‘ .2.’ 1' ' L’hh’hfac:
mammwullrlr
p. "2' ,1 a. 3'.-. *
EM‘. Li'élflffXIF-‘MPRM/k-ifi , --.
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-'| \7_
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_,~; Q5
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H‘ '.
:"a
Fig. 1767.
furnace is so arched as to reverberate the heat and
drive it back on the pipes. These pipes are placed
on the focal plane of the ellipsoid, formed by the
brickwork: G represents the grating of the furnace,
512
PRUSSIAN BLUE.
coal or coke being the fuel. B. is the pot or retort:
it is placed in a separate compartment, as seen in
Fig. 1770. e is a connecting tube from the retort
and the elliptical pipes 1?. In Fig. 1769 the shape of
this tube a will be better seen: also its cocks s s’, and
\\\\
a
i
a
a
/
Z


Fig. 1769. Fig. 1770.
its connexion with the pipes P, r‘, &c. : n is a safety-
valve, 0 the cover of the pot or retort n, and D the
door of the furnace. o is an open space or shed
roofed over, and under it the pipes are emptied. The
arrows indicate the direction of the current of heat :
it traverses the intervals between the pipes, and
ascends behind them, passing through the aperture a
in the brickwork, which may be closed by a damper.
The heat passes through this aperture and strikes
against the sides of the pot when the valve is open.
Another damper d must also be open to expose the
retort to the direct action of the fire. The smoke
escapes by a lateral passage into a chimney c. There
is a direct communication between the chimney and
that compartment of the furnace which contains the
pipes, so that the heat reflected from the part B,
strikes on the pot or retort only when the pipes are
sufficiently heated. In Fig. 1770 is shown an in-
clined plane I, shown also in Fig. 1768, also the
junction tubes which connect the 4: pipes with
their gas~burners g, g‘ and the cocks s,s2. is is are
covers closing the pipes, and having holes formed in
them which are closed by the stoppers p p. Whether
the pipes be placed vertically or horizontally, it is
desirable to be able to change the direction of the
current of gas, which is done by closing for one hour
(if the operation is to last for two hours) the cooks s1 s,
and opening s s2, in which case the gas passes through
s into the left-hand branch 0 c c e, and entering 2
passes through the channel at the bottom of 6
into :91, through the upper channel into r2, through
the lower channel into P3, and finally escapes by the
burner g1. During the second hour the cooks ss2
must be closed, and the cooks s1 s being opened, the
current goes in the opposite direction and escapes by
the burner y, where it may be ignited. The changing
of the direction of the current dispenses to a certain
degree with the labour required for stirring up the
matter contained in the pipes: but it may, however,
be necessary to pass an iron rod amongst the sub-
stances in the pipes, for which purpose the apertures
are formed so as to be readily opened and closed.

By substituting soda for potash in the above pro-
cess, prussiate of soda may be obtained.1
In the Jury Report (Class II.) is an interesting
account of an attempt made to employ the nitrogen
of the air in this manufacture. The communication
was made to Professor Graham by Mr. F. R. Hughes
of Borrowstowness. He states that in 184:4! his
firm .commenced a series of experiments upon the
large scale, at Newcastle, in company with Messrs.
Bramwell, to manufacture prussiate of potash without
animal matter, substituting the nitrogen of the at-
mosphere for it, and continued the experiments till
the latter end of 1847. In these operations a tube
or retort of fire-clay was placed in a vertical position
in a furnace so constructed that, when the formation
of carbonic oxide was prevented, sufiicient heat could
be obtained to soften a Stourbridge fire-brick through-
out its substance when exposed in the flue, or off-go,
to the full force of the fire. The lower part of the
retort was made of cast-iron, kept out of the vicinity
of the fire, and of sufficient length to afford time for
the mass heated by the fire to become cool before it
was discharged into a cistern placed below, containing
water and a protosalt of iron, into which the lower
end of the tube dipped. Provision was made at this
end of the tube to regulate the periodical discharge
of its contents, in whatever proportion was desired.
The tube was filled with wood—charcoal saturated with
a solution of the carbonate of potash of commerce,
and dried. The mixture in this state generally con—
tained about twenty per cent. of potassa (KO). By
means of an air—pump the atmospheric air was drawn
through the tube of alkalized charcoal in a continuous
stream from the top, and discharged below in a state
of nitrogen and carbonic oxide. The alkalized char-
coal was thus found to become pretty rich in cyanide
of potassium; one-half of the alkali of the cyanized
charcoal frequently being found, upon testing, to
be in combination with cyanogen; so that when
all was working well, 36 to 410 cwt. of prussiate of
potash were produced in a week by means of 7
or 8 retorts of 10 or 12 feet long in the fire, and
2 feet internal diameter. In the first experiments
much narrower tubes were employed, to which the
heat was applied only externally 5 but as both the
tubes and charcoal are bad conductors of heat, suf-
ficient quantities could not be operated upon, and it
was found necessary to build larger tubes, with fire-
bricks of the above dimensions 5 leaving a circle of
small apertures or chinks in the tube, every third or
fourth tier of bricks, through which the intensely
heated gases, nitrogen and carbonic acid, were drawn
from the-flue by the action of an aspirator. The
‘mass in the interior of the large tubes was thus made
so hot, that an iron rod one inch in diameter became
white hot when thrust down in the centre and allowed
to remain there 5 or 10 minutes. The next im-
provement was to use the alkalized charcoal undried,
and to aspirate the air from below upwards, instead

(1) Newton's London Journal of Arts and Sciences, vol. xxi.
1843. "
PRUSSIAN BLUE:PRUSSIC ACID?
513
of downwards; the surplus heat drying the alkalized
charcoal before it reached that part of the retort in
which the cyanide was produced, a length of 6 to 8
feet. The top of the retort was in this case rendered
air-tight, and the cyanized mass discharged below as
before. Through 7 or 8 retorts of the above size
about 2,400 cubic feet of alkalized charcoal were
passed in a week, and about 1,200 to 1,400 cubic
feet of cyanized charcoal were obtained, nearly one-
half of the charcoal being consumed. There were
two great drawbacks to this process—one, the im-
mense quantity of material to be lixiviated for a small
return of prussiate; the other, and by far the more
important, an extraordinary waste of potash in the
process, upwards of three parts by weight being
consumed in producing one of prussiate. The whole
of this waste could never be properly accounted
for. About one part of potash was recovered in
the state of prussiate. It was found that another
part was lost in the small refuse charcoal, which could
not be lixiviated to pay, and the remainder appeared
to be partly combined with the bricks of the retort,
and partly dissipated by the chimney. In 1847
the plan was abandoned after a loss of many thou-
sand pounds. But the possibility was proved of
producing large quantities of cyanide of potassium,
by drawing intensely-heated nitrogen and carbonic
acid gases through a mixture of potash and charcoal,
with the difiiculty of carrying this out as a manufac-
turing process from the great waste of potash.
These experiments were more directed to making
the air process practicable, for the purpose of manu-
f acture, than to ascertain upon what principle the
formation of cyanogen depended; for it was im-
material, in a manufacturing point of view, whether
the cyanogen were produced from the nitrogen of the
atmosphere, or from the ammonia which the charcoal
was always found to contain. The means of nicely
observing the changes were lost, from the necessity
which existed in operating upon large masses, to draw
the intensely-heated gases from the fire into the
body of the tubes in order to bring the alkalized
charcoal to a proper heat for the production of cyanide
of potassium. It is probable, that some part, at least,
of the cyanogen was furnished from the ammonia in
the charcoal, which in separate experiments in the
laboratory was found not to be entirely given off at a
red heat. Some alkalized charcoal, also brought to
a proper heat in a porcelain tube, produced a con-
siderable quantity of cyanide of potassium without
the presence of air, the ends being stopped up. On
the other hand, when the retorts were filled with
charcoal noi alkalized, and the heated gases drawn
through, no formation of either cyanogen or hydro-
cyanite of ammonia could be detected.
A paper by Professor Marchand, in the “ Chemical
Gazette,” vol. viii, on the presence of nitrogen in cast—
iron and steel, appears to throw some light upon the
subject. He has shown that when carbon is com-
bined chemically with iron, and treated with potas-
sium, in the presence of nitrogen, cyanogen is pro-
duced. Mr. Hughes thinks it probable that the first
von. 11.

step in their process was the formation of a carburet
of potassium, which, by combining with the aspirated
nitrogen, produced the cyanide of potassium. This
might be ascertained by examining the remainder left
in the retort, after the production of the potassium in
the ordinary way from bitartrate of potash, testing
the quantity of cyanide it contained, if any, and then
testing the increased quantity after heating it in
nitrogen gas. In the foregoing process soda was
substituted for potash with a similar loss.1
Messrs. Bramwell, of Newcastle-upon-Tyne, are
extensive manufacturers of Prussian blue. Their
factory was established about 80 years ago, and for a
considerable period a large quantity of the pigment
was sent every year to China. A spring shipment
was made of about 2,0001. in value, which was often
followed by another in autumn. It was first sold at
2 guineas per pound, made up in neatly finished one-
pound packages, but had fallen in 1815 to 108. 66%,
and about 1820 to 2s (iii. For the last ten years the
price of Prussian blue has been ls. 9d. per lb. It has
been stated that the chief demand for Prussian blue in
China was for the purpose of colouring green teas.
It must not, however, be forgotten that blue is the
favourite colour of the Chinese. The cause of the
cessation of the trade is curious. A common Chinese
sailor who was brought to England in an East
Indiaman, had occasion to visit a Prussian blue
manufactory, and thus learned the art of making it.
On his return to China he set up as manufacturer of
the article, and was so successful that in a short time
the whole of China was supplied with the article by
native manufacturers.
Prussiate of potash was not known in commerce in
a crystallized state until about the year 1825, when
it was sold at 5s. per lb. For some years before that
date a weak solution of the salt, or of the fluxed mass
of animal matter and potash, had been sold at ls. per
gallon. The rapid progress of the manufacture will
appear from the following estimate of the annual pro-
duction in the United Kingdom :
Annual Production.
8. d.
From 1825—1830 about 10 tons at 5 0 per pound.
1830-1835 ,, 4o ,, 2 c
1835-1840 ,, 200 ,, 1 4
1840-1845 ,, 700 ,, 1 4.
1845—1850 ,, 1040 ,. 1 3
There are eleven prussiate works in the United
Kingdom, of which the aggregate produce is, when
the salt is in demand, about 20 tons per week. The
two largest works are those of Messrs. Bramwell and
the Hurlet and Campsie Alum Company. The value
of the annual product for the last 5 years is estimated
at 145,600].
PRUSSIC ACID. This compound, so remarkable
for its poisonous properties, is a cyanide of hydrogen,
HCy, and from its acid reaction is also named
lzg/cirocyanic acid. It was discovered by Scheele in

(1) The above process was considered to have succeeded in a
chemical point of view, but was not sufficiently economical for
the manufacturer, chiefly because the fire-clay tube did not long
resist the combined action of the alkali, and of the excessive
heat.
LL
5111
PUMICE-STONE—PUMP.
1782. The pure anhydrous acid may be prepared in
the following manner. A long glass tube is filled
with dry cyanide of mercury, and is connected at one
end with an apparatus for furnishing dry sulphuretted
hydrogen gas, while to the other end is attached a
narrow tube which is passed into a narrow-necked
bottle plunged into a freezing mixture. 011 applying
a gentle heat to the tube the cyanide of mercury is
decomposed in contact with the sulphuretted hydrogen,
with the production of sulphide of mercury and
cyanide of hydrogen, the latter being condensed in the
cold bottle in the liquid form. To prevent the pro-
duct from being contaminated with sulphuretted
hydrogen, a portion of the cyanide of mercury is left
undecomposed. The pure acid is a thin, colourless,
volatile liquid: its density at 45° is 07058 : it boils
at 7 9°, and solidifies when cooled to zero: its odour
is powerful and characteristic, resembling that of
peach blossoms or bitter almond oil; it has but a
feeble acid reaction, and mixes with water and alcohol
in all proportions. It is a powerful poison even when
largely diluted with water, and its vapour, if only
slightly inhaled, produces giddiness and headache.
Ammonia and chlorine are the best antidotes. It is
difficult to preserve the acid in its pure form; it soon
darkens and deposits a black substance containing
carbon, nitrogen, and probably hydrogen, while
ammonia and other products are disengaged. The
decomposition is greatly assisted by exposure to light.
The dilute acid is also subject to decomposition, but
in a less degree.
There are various methods of obtaining the hydrous
acid. When large quantities are required the best
method is to decompose at a boiling heat the yellow
prussiate of potash by means of dilute sulphuric acid.
The prussic acid made in this way is less liable to
decomposition than that above described. The addi-
tion of a few drops of hydrochloric acid will also
preserve the dilute prussic acid.
Various parts of many plants belonging to the
great natural order, Rosacew, such as bitter almonds,
the kernels of plums and peaches, the leaves of the
cherry laurel, 850., yield on distillation with water
a sweet-smelling liquid containing hydrocyanic acid.
“This is probably due in all cases,” says Mr. Fownes,
“ to the decomposition of the amg/gclalz'a preexistent
in the organic structure. The change in question is
brought about, in a very singular manner, by the
presence of a soluble azotised substance, called emulsz'n
or synapzfasc, which forms a large proportion of the
white pulp of both bitter and sweet almonds. This
substance bears a somewhat similar relation to amyg-
dalin, that diastase, which it closely resembles in
many particulars, does to starch. Hydrocyanic acid
exists ready formed to a considerable extent in the
juice of the bitter cassava.”
PUG-MILL»— See BRICK—POTTERY and Pon-
CELAIN.
PULLEY.—See Srx'rrcs.
PUMICE-STONE. Pumice is regarded as a
vesicular variety of onsrnrxn. It has a finely cellular,
spongy texture, and is often sufficiently light to float

in water. The minute cells being long and fine, it
appears as if it had a fibrous structure. It occurs
near volcanos which produce felspathic lavas, and its
light and cellular structure appears to be due to the
inflation of volcanic steam or gas. Its colours are
white, grey passing into yellow, brown or black. The
pumice from Lipari was found to consist of silica
7 7 '50, alumina 17 '50, potash and soda 3, peroxide
of iron 1'75. As much as 6'21 per cent. soda, and
398 potash has been found in pumice from Ischia. It
is largely exported form (lampo Bianco, one of the
Lipari islands, where it forms a hill from 800 to
1,000 feet high, and from the Ponza islands. At
Andernach on the Rhine pumice is used as a building
stone.
Pumice-stone is much used in various branches of
the useful arts for dressing leather, grinding and
polishing the surfaces of metallic plates, and in the
state of powder for polishing various articles of cut
glass. It is reduced to powder by crushing it under
a runner and sifting, in which state it is used for
brass and other metal works, and also for japanned,
varnished and painted goods; for the latter purposes
it is applied on woollen cloths with water.
PUMP. The pump is usually defined as a
hydraulic machine for raising water by atmospheric
pressure. It will, however, be found in an extended
view of pumps that this definition is too limited. We
will, however, first speak of common pumps, to which
the definition does apply, and in these we shall find
much that is ingenious and highly scientific, although
they were invented long before the principle of
atmospheric pressure was known: indeed it was the
lucky accident of a pump being at fault which led to
the discovery of that important principle. Professor
Robison1 regards the pump as “ the last step in the
progress of man’s ingenuity for raising water.”
Nothing like it is known among rude nations : it was
not even known in China until the time when Euro-
peans visited that country, and it is still rarely seen
in those parts of Asia which are not frequented by
Europeans. It does not appear to have been known
to the early Greeks and Romans, but may have come
from Alexandria, where the physical and mathematical
sciences were cultivated by the Greek schools under
the protection of the Ptolemies. Pliny and Vitruvius
refer to the performances of Ctesibius and Hero as
curious novelties. The Egyptian wheel was for many
ages in common use all over Asia, and it is still em-
ployed in many parts: it was brought by the Saracens
into Spain, where it has continued to be used under
the ancient name of maria. Some years ago certain
Danish missionaries found in Siam what Dr. Robison
calls the “immediate offspring ” of the noria. It was
a wheel turned by an ass, and carrying round, not a
string of earthern pots as in the noria, but a string of
wisps of hay which were drawn through a wooden
trunk, forming a sort of rude chain pump. It is used
for watering the rice fields. This machine is pro-
bably of great antiquity, and may be regarded as the

(1) Mechanical Philosophy, vol. This chapter on the Pump
forms the article PUMP in the Encyclopccdia Britannica.
PUMP.
515
immediate predecessor of the common pump, or rather
of the forcing pump, which is
simpler in its structure than the
common house/told or sum/‘£022
pump. The forcing pump is
shown in section Fig. 1771. It
consists of a working barrel in
which a tightly fitting piston
r works up and down. At
the bottom of the barrel is
a pipe leading down into the
well or pond, the pipe being
furnished with a strainer at the
bottom to keep out stones and
gravel. The hole or point of
; iunction between the barrel and
ill-$3,151..‘ _ lltllllllfih ‘
3%‘


_____—_-—
out from the side of the barrel
is an ascending tube 1‘, also
closed at the point of junction by a valve 0, opening
outwards.
Bearing in mind the law of atmospheric pressure
as explained under Am, and the action of valves in
the exhausting and condensing syringe, Fig. 19, and
in the air-pump, Fig. 20, the action of this pump will
be readily understood. Supposing the piston to be
at the bottom of the barrel, and to be drawn upwards,
a vacuum, or empty space, would evidently be left
between the bottom of the piston and the bottom of
the barrel, were it not that air from the pipe forces
open the valve at the bottom of the barrel and follows
the piston. But in proportion as the air quits the
pipe water enters it, and remains suspended therein
by atmospheric pressure acting on the surface of the
water in the well. The piston, having been raised to
the top of the barrel, is now forced down, the lower
valve closes, and the air in the barrel forces open the
side valve and escapes. On again raising the piston,
the barrel is again filled with air from the pipe, and
is again expelled by the side tube when the piston is
driven down. In this way, by a few strokes of the
piston, the whole of the air is drawn out of the pipe,
and water rises in its place, provided the height does
not exceed 34: feet, at about which height it is
balanced in the pipe by the pressure of the atmo-
sphere on the surface of the water in the well. As that
pressure is equal to about 15 lb. on the square inch of
surface, so a column of water in the pipe, equal in sec-
tional area to 1 square inch, and about 341 feet high,
will weigh 151b, and thus the atmospheric pressure
and the column of water counterbalance each other.
If the pressure of the air, as indicated by the baro-
meter, fall below 30 inches of mercury, it will not
amount to 15 lb. on the square inch, and consequently
will not support 341 feet of water, but a foot or two
less; so also if the pipe, leading from the working
barrel to the well, exceed 341 feet in length, no water
can be drawn, because the atmospheric pressure is not
under ordinary circumstances capable of counter-
balanoing a larger column than about 34: feet of
water. [See BAROMETER-J But to return to the

forcing pump, Fig. 1771. Supposing water to have
followed the piston in its upward motion, it is evident
that, in the down-stroke, the bottom valve will be
closed, and the side valve open, and the water urged
by the force of the piston will pass through the side
valve and ascend the tube '1‘. On raising the piston,
the side valve will close, and prevent the water in 'r
from returning into the barrel. By continuing these
actions, drawing up water from the well during the
up-stroke of the piston, and forcing it up the tube T
during the down-stroke, water can be raised or forced
to a considerable height above its level. This, then,
is probably the simplest
form of pump. The struc~
ture becomes a little more
complicated in the suction
pump, Fig. 17 7 2; for here,
in addition to the valve
closing the bottom of the
barrel, there is a valve in
the working piston which
alternates in its action with
the bottom valve. Thus,
on raising the piston in the
direction of the arrow, the
bottom valve opens and
draws, first, air, and then
water, from the pipe leading
into the well. On lowering
the piston the bottom valve
shuts, and the piston valve
opens, and allows the air
or water to pass through
the valve and occupy a position above the piston.
This state of things is shown in the right-hand
figure. The piston having arrived at the bottom of
the barrel is again raised; air from the pipe opens
the lower valve and follows the piston, water sup-
plies the place of the air drawn out of the pipe; this
second portion of air is expelled from the barrel by


Fig. 1772.
lowering the piston, and thus, by a repetition of these.
actions, all the air is drawn out of the pipe, and
water follows the ascent of the piston, on lowering
which, the water opens the valve, accumulates above
the piston, and as this is raised it flows over by the
spout, the flow being continuous so long as the pump-
handle is worked.
The form and arrangement of the piston are of
great importance, and have been explained by
Dr. Robison, in the following terms :--“ The piston
is a sort of truncated cone, generally made of wood
not apt to split, such as
elm or beech. The small
end of it is cut off at the
sides so as to form a sort
of arch by which it is
lllll
fastened to the iron rod or L '7
if?» m
spear. [See Fig. 1773.]
The two ends of themconi-
cal part may be hooped
with brass. The cone has its larger end surrounded
with a or hand of strong leather, fastened with


Fig. ms.
L L 2
516
PUMP.
nails, or by a copper hoop, which is driven on it at
the smaller end. This band should reach to some
distance beyond the base of the cone; the further
the better: and the whole must be of uniform thick-
ness all round, so as to suffer equal compression
between the cone and the working-barrel. The
seam or joint of the two ends of this hand must be
made very close, but not sewed or stitched together.
This would occasion bumps or inequalities, which
would spoil its tightness; and no harm can result
from the want of it, because the two edges will be
squeezed close together by the compression in the
barrel‘. It is by no means necessary that this com-
pression be great. This is a very detrimental error
of the pump-makers. It occasions enormous friction,
and destroys the very purpose which they have in
view, viz. rendering the piston air-tight; {for it causes
the leather to wear through very soon at the edge of
the cone, and it also wears the working-barrel. This
very soon becomes wide in that part which is con-
tinually passed over by the piston, while the mouth
remains of its original diameter, and it becomes im-
possible to thrust in a piston which shall completely
fill the worn part. Now, a very moderate pressure
is sufficient for rendering the pump perfectly tight,
and a piece of glove-leather would be suificient for
this purpose, if loose or detached from the solid cone;
for suppose such a loose and flexible, but impervious
band of leather put round the piston and put into the
barrel; and let it even be supposed that the cone does
not compress it in the smallest degree to its internal
surface. Pour a little water carefully into the inside
of this, sort of cup or dish, it will cause it to swell out
a little, and apply itself close to the barrel all round,
and even adjust itself to all its inequalities. Let us
suppose it to touch the barrel in a ring of an inch
broad ‘all round. We can easily compute the force
with which it is pressed. It is half the weight of a
ring of water, an inch deep, and an inch broad. This
is a trifle, and the friction occasioned by it not worth
regarding: yet this trifling pressure is sufficient to
make the passage perfectly impervious, even by the
most enormous pressure of a high column of incum-
bent water: for let this pressure he ever so great, the
pressure by which the leather adheres to the barrel
always exceeds it, because the incumbent fluid has no
preponderaiing power by which it can force its way
between them, and it must insinuate itself precisely
so far, that its pressure on the inside of the leather
shall still exceed, and only exceed, the pressure by
which it endeavours to insinuate itself ; and thus the
piston becomes perfectly tight with the smallest pos-
sible friction. This reasoning is perhaps too refined
for the uninstructed artist, and probably will not per-
suade him. To such we would recommend an exami-
nationof the pistons and valves contrived and executed
by that Artist, whose skill far surpasses our highest
conceptions-the all-wise Creator of this world. The
valves which shut up the passages in the veins, and
this in places where an extravasation would be fol-
lowed by instaut death, are cups of thin membrane,
which adhere to the sides of the channel about half-

way round, and are detached in the rest of their cir~
cumference. When the blood comes in the opposite
direction it pushes the membrane aside, and has a
passage perfectly free. But a stagnation of motion
allows the tone of the (perhaps) muscular membrane,
to restore it to its natural shape, and the least motion
in the opposite direction causes it instantly to, clap
close to the sides of the vein, and then no pressure
whatever can force a passage.1 What we have said is
enough for supporting our directions for constructing
a tight piston. But we recommend thick and strong
leather while our present reasoning seems to render
thin leather preferable. If the leather be thin and
the solid piston in any part does not press it gently to
the barrel, there will be in this part an unbalanced
pressure of the incumbent column of water, which
would instantly burst even a strong leather bag; but
when the solid piston, covered with leather, exactly
fills the barrel, and is even pressed a little to it, there
is no such risk; and now that part of the leather
band which reaches beyond the solid piston performs
its office in the completest manner. We do not
hesitate, therefore, to recommend this form of piston,
which is the most common and simple of all, as pre-
ferable, when well executed, to any of those more
artificial and frequently more ingenious constructions
which we have met with in the works of the first
engineers.”
The piston is sometimes formed of flat discs of
leather or of felt, perforated in the centre for fitting on the piston-rod. I
These discs are pressed together be-
tween 2 metal plates, which move
upon a worm at the end of the rod,
so as to allow them to be screwed
up tight, and by this means the
edges of the discs are made to pre-
sent an equable cylindrical surface
exactly corresponding with the working barrel in
which it moves.
The form of the valve is also subject to considerable
variation. The trap-valve a, Fig. 1775, is a very com-
mon form. It is simply a plate of metal, moving on
a hinge, and covering or closing the hole in the bot-
tom of the working-barrel. In order to do this more
effectually its under surface is covered with leather:
sometimes, in order to increase the mobility of the
valve, the hinge itself is of leather, in which case the
leather is attached by a plate of metal to the fixed
part about the hole, and weight and solidity are given
to the leather by means of a plate of metal over the
hole as before. At 6 is the section of a conical-valve,


(1) It has been suggested to us that Dr. Robison in this illustra-
tion is not so happy in his reasoning as usual. “The valves in the
veins have no tendency to prevent extra'uasation or escape of
blood from the vessels, but tend solely to prevent its return in the
wrong direction. I-Iis description of the valves hardly conveys
the impression of small cup-like folds of membrane opening a
free passage, by compression against one side of the vein, for
mom Passing in the right direction; that is, pressing against the
outside of the cup; but spreading out and expanding so as to
press against each other or against the opposite side of the vein
when the blood tends to enter the inside of the cup and thrust it
outward.”
PUMP.
517
consisting of a horizontal section of a cone fitting a
conical hole in the bottom of the barrel: the valve is
supported on a guide-rod which passes through an
arm fixed across the under-side of the barrel. In
working the pump, this valve admits of being raised
to the extent of the guide-rod by the air or the water
pumped up, and it falls by its own weight into its
place when the action is over. At a is a tall or s/wt-
mlve, which acts in the same manner as 6, but being
spherical, it fits the part which it is intended to close in
any position without the assistancev of a guide-rod.


Fig. 1775.
It is necessary, however, to prevent the ball from
being carried too high, to place a curved wire or
detent at a certain distance above it. The ball may
be hollow or solid, or loaded within with some heavy
metal so as to adjust it to the work which it has to do.
At (Z is a butterfly-valve, adapted to the piston: it is
similar to a, only double.
It will be evident from the foregoing details, that
in the erection of a pump the depth of the Well is
a matter of great importance, for if the distance be-
tween the body of the pump and the surface of the
water exceed 341 feet, no water will ever be raised,
since the atmospheric pressure is never capable of
supporting a higher column than as feet of water.
In practice, however, considerable deductions must be
made from this limit. Supposing even that the work-
ing parts could be made so perfect as to produce an
absolute vacuum in the suction-pipe, Fig. 17 7 3, the
varying pressure of the air would only occasionally
allow so high a column as 341 feet to be raised. The
barometric column in England varies between 28 and
31 inches in height, and this does not represent an
average of more than 30 feet in a column of water. If,
therefore, the surface of the water to be raised exceed
this depth below the level of the ground, it will be ne-
cessary to erect the body of the pump in the well at
a certain moderate distance from the surface, and to
lengthen the piston-rod so that it may be conveniently
worked from the surface. This is the arrangement
adopted for raising the drainage water from mines.
A force-pump, similar in principle to that shown in
Fig. 1772, is used. The pump-body is erected at the
bottom of the mine, and dips into the sump in which
the waters are collectedfor the purpose of being
raised. The pipe T might, in theory, be at once
carried to the surface, however deep the mine, if it
were possible to make the piston P water-tight, and
the cylinder, or body in which it works, sufficiently
strong to bear the required force: but as the first
of these conditions is not practicable, the plan adopted
is to divide the column into a certain number of
- a cistern o.

stages, a distinct force—pump passing from ‘one stage
to another. A rod nn, Fig. 1776, descending from
the surface to the bottom of the mine, has attached
to it, at certain intervals, piston rods, 22 in’, each with
Q:
E
m
6+
0
t3
t2‘)
CF
‘5".
t5
O'Q
E.
O
in
"d
5:‘
B
"d
3
body a which dips mto
By‘ the action
of, the steam v-engine, or f
other motive power, on the surface, the rod R a is \
moved up and down, where-
by motion is imparted to 1;\
the pistons 10;)’: water is
first raised from the sump,
forced up the pipe, and dis-
charged into a cistern 0:
the pump body of the next
superior force-pump dips
into this cistern: as the
rod It moves up, a valve
below 2; opens and admits ;
water from 0 into the pipe;
the rod R then moves down,
the valve below 22 shuts and
the valve 0 opens; and by \
continuing these actions, .
water is raised higher and A -
higher in the pipe, and at ‘ \ L
length overflows into 0’, :
which, in its turn, serves as \
the well to the force-pump :.
immediately above it. It i ,
must be remarked, that in A; if .
this arrangement no more force is expended than '


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would be 1eqiu1ed for ra1s- its; $9.‘. 1 , M.‘ ii’; \§§
mg water by a contlnuous ,3 , , 1 {5.1 i,|\
tube T,-Flg. 1772, ‘to the ilk
same height; but with the 'll- ~§
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unbroken tube '1.‘ there ; ‘. ‘ _' s
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to WlllCll we have already azapp- "run a a
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V
Force-pumps have, how- \
ever, been constructed ca-
pable of raising water upwards of 500 feet above
the level of the source, as in the pumps of Madly,
erected for supplying Versailles with water from the
Seine. A section of one of these pumps is repre-
sented in Fig. 1777. It consists of a metallic piston
1?, of much greater length than diameter, moving
‘ water-tight through a stuffing-box, and passing into
the body of the pump with a considerable range, but
without being in contact therewith. The suction-
pipe is closed by means of two valves 12 v, and there
is also a valve 2:’ in the force-pipe. When the piston
1’ is raised a vacuum is left behind it, which is in—
stantly filled by the ascent of water through a 0.
During the ascent of r the valve 22’ is closed, but in
its descent a v are closed, and 2)’ opened, and water
is forced along and up the force-pipe to the reservoir
situated at the height of 155 metres, or about 508%
feet above the suction-pipe. Now there is a- Curious
'/
518
PUMP.
source of inconvenience arising in pumps of this
construction which has to be provided against.
Water exposed to the atmosphere absorbs a notable
quantity of that fluid, which may be made very evi-
dent by placing a tall glass of cold
water under the receiverof an air-
pump and exhausting the air. A por
tion of the dissolved air is also set
free on agitating the water contain-
ing it. Now as the water rushes
through the valves '0 o, a portion of
this air is set free and escapes up
into the narrow space between the
piston and the interior of the pump
cylinder, displacing from that space
the water which is necessary to the
proper action of the
pump, for it is this
water which forms
the fulcrum or point




' of reslstance 1n forc-
ing the water up
the force-pipe. The
Fig. 1777. first action of the
descending piston is
therefore to com-
press this air, so as to make its elastic force cor—
respond with the pressure produced by the column
of water in the ascension-tube, and until this takes
place no water can be forced through the valve 0’.
Hence not only is the function of the piston greatly
deteriorated, and less water forced up the tube than
would be if no air existed around the piston, but
the height of the column may be so far diminished
that the water does not reach up to the reservoir
which it is required to fill. To get rid of these objec-
tions it is necessary to provide means for removing,
from time to time, the accumulation of air in the
space around the piston; for which purpose the
piston is perforated with a channel z‘, shown by the
dotted lines, opening at its lower extremity into the
space surrounding the piston, and closed at the top
by a stop-cock Iz; so that all that is necessary is
‘occasionally to open this stop-cock, when the piston
is at its lowest point and the air most compressed,
and the air will then rush out through 7,‘, and its place
be supplied by water. The column of water con-
tained in the ascension-pipe, when at rest, produces
a pressure equal to 15 atmospheres :: 225 lb. on the
square ‘inch. The piston, however, has to overcome
a pressure equal to 17 atmospheres, the resistances
occasioned by the motion of the water in the pipes
producing an increase of pressure equal to 2 atmo-
spheres.
Ill pumps for domestic use, where it is required to
force water into the upper floors, the suction pump
and the force pump are combined, as shown in Fig.
1'7 7'8. rI‘he Zvmire or pump-handle 33 moves upon an
axis at n, so arranged that, on working the brake,
the point ‘A’ shall move up and down, but in a con-
trary direction; when B is raised A’ is depressed,
and vice versrZ. Attached to a joint at A is- a

rod 7', moving
in a guide and
adjusted to the
proper length by
the nut 92: ,at-
tached to the
lower extremity
of this rod is the
piston r; the suc-
tion-pipe T passes
down into the
well as before.
Now it is evident
that by the mo-
tion of the pis-
ton-rod up and
down water will
be raised into the
pump barrel, as
in the common
pump; during the
upward motion of
the water the two
valves or) will be
raised, and water











will be discharged
from thecock nearg§xf ‘ I I l’. J] the upper 11 ,- dur-
yap - my“ 1 ' ~\\\\§\ - . s . a. . mg the downward . 4. altar“
motion the two
valves a a will be
closed, and the water below the piston will force
open the piston-valve and rise above it; so far the
action is the same as in the common pump. If now
the cock near the upper 12 be closed and the action
continued, then water will rise in the tube ‘r, as in
the ordinary force pump. -
In the pumps hitherto described, the motion of the
water is intermittent, either in the suction-pipe or in
the force-pipe. In the suction-pipe the water moves
only when the piston is ascending, and in the force-
pipe only when it is descending. This occasions
a great loss of power; for not only must the water
he put suddenly into motion after each stroke, but
the velocity acquired by the motion of the water in
the pipe is not turned to account in doing work.
Indeed, it appears from the experiments of M. Morin
that the amount of power lost in lifting and forcing
pumps amounts to from 55 to 80 per cent. of the
whole. “ So that of the work (in pounds one foot
high) done by the motive power to drive the pump
only 415 per cent. in the best and 18 per cent. in the
worst pumps, is found to be yielded, when the weight
of water actually raised in pounds is multiplied by
the height to which it is raised in feet, the rest of the
work being lost in the passage of the water through
the pump.” The causes of this loss of power may be
sought, 1. In the small size and peculiar construction
of the valves. 2. In the proportion of the section of
the barrel to that of the suction and force-pipes.
3. In the form of the suction-pipe at the extremity
where the water enters it, and of the force—pipe at
. PUMP.
5519'
the extremity where the water is discharged. 4.. In
the forms of these pipes where‘ they unite with the
barrel. 5. In the proportion of the length of the barrel
to the depth from which the water is raised. There
is no doubt that the loss of power would be greatly
lessened by increasing the size of the valves, so as to
diminish that sudden variation in the section of the
stream which is produced by the valves. The small
size of the valves also occasions a sudden variation in
the velocity of the ‘stream, involving a loss of power
varying as the square of the difference of the two
velocities, and therefore dependent on the ratios of
the sections of the suction-pipe and force-pipe to the
section of the barrel. Want of attention to these
ratios leads to the second source of loss of power.
With respect to the third source, it is well known
that the form of the nozzle by which water is dis-
charged from a force-pump greatly influences the
amount of the discharge; the form of the extremity
of the suction-pipe by which water enters has an
equal effect in facilitating its ingress; for it appears
that by expanding the extremity of the pipe, by which
the water enters, into a cone, of which the diameter
of the wider end is 1.2 times that of the other, the
contraction of tire oez'izl may be nearly destroyed, the
coefficient of the ingress being increased‘ from '62 to
‘967. That is to say, under similar circumstances
tending to cause water to enter the ends of two
pipes, one expanded and the other left straight, nearly
10 parts of water would enter the expanded pipe,
while about 6 parts were entering the straight pipe.
A similar result may be obtained by expanding
the extremity by which the water is discharged.
By uniting these expedients a discharge may be
obtained which is greater than that due to the
section of the pipe; thereby practically converting
the contraction into an expansion of the fluid vein.
The ingress of the water is also facilitated by ex-
panding that extremity of each pipe by which it com-
municates with the barrel, and the neglect of it leads
to a fourth source of loss of power. “ A‘ fifth cause
to which attention appears not hitherto to have been
directed is the loss of power due to the communica-
tion of an unnecessary velocity to the water raised.
Any one who gives a succession of quick strokes to
the piston of a common suction-pipe, allowing suffi-
cient time between them for all the water which can
find its way into the barrel‘ to enter it, will find the
discharge per stroke to be considerably greater than
when the piston is raised'slowly. The reason of this
is obvious: a certain amount of power, and no more,
is required to be done on the piston in order to raise
enough water from the well to fill the barrel. If
more than this be done, the surplus manifests itself
under the form of ads viva communicated to the
water, by which vis viva, if space be afforded for it to
take effect (as in the common suction-pump by efflux
from the spout, or by the raising of the valve in the
barrel), more water is brought into the barrel than is
due to the volume generated by the piston. Half
(1) This term is explained under Hxnnos'rx'rrcs and Hrnno-
DYXAT-HCS, Fig. 1199.


the vis viva of the water under the’ piston at the end
of the stroke measures this surplus work. If a sufli.
cient pause be allowed, and if the head of water
above the piston be not considerable, as in the com-
mon suction-pump, the upward rush of the water
beneath it at the end of the stroke will lift its valve,
and a portion of the surplus work (representei by half
the vis viva) will take effect in the elevation of more
water into the barrel than would fill the space gene-
rated by the piston; and thus is explained the fact
of the greater discharge from such pumps when
worked by quick strokes with intervening pauses,
than when worked slowly. If the head of water
above the piston be, however, considerable, as in the
force-pump, any vis viva which may remain in the
water at the end of the stroke will produce a shock
and a corresponding loss of power. The shock, com-
monly experienced in the action of foree-pumps, is
accompanied by a violent and prejudicial action of the
valves, especially when they are of metal. When. the
down-stroke of the piston follows so rapidly on the up-
stroke as to meet the ascending stream produeed by
the preceding stroke, the resistance to its descent is
increased, as well as the loss of power due to the
commotion of the particles of the fluid it traverses.
It is obvious, therefore, that the proportions of a
pump to be worked by a given motive power, should
be such that the power to be expended at every
stroke may just bring the water raised to rest at the
end of each stroke. It is immaterial in what pro-
portions this work is distributed over the stroke, or
under what varying degrees of‘ pressure it is gene-
rated, provided that the pressure never exceeds that
of the atmosphere on the surface of the piston. If
this pressure be exceeded, the piston may separate
itself from the water beneath it in the barrel, the
pump drawing air; and this is more likely to occur
at the commencement than at any other period of
the stroke, the motion of the water at that point
being necessarily slow. To communicate a finite
velocity to the water at the commencement of the
stroke, or while the space described by the piston is
still exceedingly small, requires a much greater
pressure than afterwards; and the greater, as the
section of the suction-pipe is less as compared with
that of the barrel and as the lift is greater. Thus at
the commencement of the stroke a finite velocity
of the water can only be obtained by an extraordinary
effort of the motive power, associated with the chance
of drawing air and of a shock, if the pressure he
suddenly applied. A remedy for some of these evils
in the working of a pump has been sought in the
application to it of a second air-vessel communicating
with the suction-pipe immediately below the barrel,
or with the top of the suction-pipe and the bottom of
the barrel. The commencement of each stroke is
eased by a supply of water from this air—chamber to
the space beneath it. The influx of the water into
that space is aided by the pressure of the condensed
air in the air-chamber, and when the stroke is com-
pleted the state of condensation of this air is, by the
momentum of the water in the suction-pipe, restored,
520
PUMP.
causing it to rush through the passage by which that
pipe communicates with the air-chamber. Thus by
this contrivance, the surplus-work, or half the vis viva
which remains in the water of the suction-pipe at the
conclusion of each stroke, is stored up in the com-
pressed air of the air-chamber, and helps to begin the
next stroke of the piston.” 1 The nature of the action
will be better understood by considering that of the
water‘ mm described under Hrnnos'rnrrcs and Er-
DRODYNAMICS. Among the pumps of the Great Ex-
hibition the air vessel placed on the suction-pipe was
adopted'in the Canadian Fire-engine} inS/zalders’spump,
and in Segfie’s pump. In the Canadian engine a distinct
copper chamber a a was fixed on the suction-pipe sp,


Fig. 1779.
as shown in Fig. 1779. From the action of the pump
this suction air-chamber was always about half full of
water. This was seen in Selfe’s pump, where the air-
chamber and pump barrel were of glass. It was seen
that in the ordinary pump if a stroke were made very
suddenly and rapidly the water could not be started
‘soon enough to follow the piston; but, as it were,
lagged behind, leaving a vacuum under the piston, and
at the end of the upward stroke the piston went
down with a jump, (if tight enough to prevent air
being drawn in,) rendering of course all that part of
the stroke useless. But with the air-chamber, when
a rapid stroke was made, the water in the lower part
of the air-chamber was close at hand, ready to follow
the piston up, the air above the water expanding to
fill the space. Then as soon as the up-stroke was
done, and while the down-stroke was being made, the
water in the suction~pipe, by the impetus already
given to it and by the contraction of the air in the
chamber, flowed into this air-chamber and partially
filled it as before. So that practically, when pumping
very fast and with a large air-chamber, the water is
always moving steadily up the suction-pipe, and the
pump barrel draws its supplies from the air-chamber in
great part. It was found that Shalders’s pump when
worked very rapidly actually threw more water than
when worked slowly, evidently from this uniform
unchecked motion produced in the rising column of
water. Ordinary pumps in such case either draw air
or else work in jumps, from the partial vacuum under
the piston.
We must also refer particularly to Lez‘esz‘u’s pump

(1) Jury Report. Class V.
(2) The Fire Engine is described in our article FIRES, Extinc-
tion of.

and fireenyz'rze', which in the Jury Report are “ highly
commended for the ingenious, simple, and economical
arrangement of the pistons, the large dimensions; of
the valves, and the large sectional area of the suction
and force-pipes, in comparison with the barrel.” The
piston is a hollow perforated brass cone, to the inte-
rior of which is applied a circular piece of leather,
like a filtering paper to a funnel, but
having a sector cut out instead of being
folded: (see Fig. 1780 :) the radial
edges of the leather overlap, and its
periphery projects beyond the edges of
the cone, thus adapting itself to the Fig-1780.
internal surface of the barrel. When the piston is
used for suction it is fixed to the rod with the base
upwards, as shown in Fig. 1781, and when for
forcing with the base downwards, as in Fig. 17 82.3
In the return stroke, the water, passing through the
perforations of the brass cone, finds a passage between
the loose radial edges of the leather, which it sepa-
rates. The valve in the air vessel is a simple disc of
leather, screwed down at its centre on a perforated
plate.
The advantages of these valves lay in the facility
with which they could be replaced when injured, and,
secondly, in their little liability to be choked by
sand or gravel drawn in with the water. Both the
valves are formed of simple fiat pieces of sole-leather
without any moulding or bending; and it was found
by trial that a new valve, for either place, could be
cut out with a common pocket-knife, the old one
removed, and the new one put to work in less than
five minutes. The piston—valve, as already stated, is
a disk with a sector cut out, as in Fig. 1780, so as
when folded up to fit inside the cone of brass. 1, Figs.
1781, 1782, shows this valve secured in the perfo-
rated brass cone 0 by the extremity of the piston-rod r.
The suction-valve
is a simple disk, 22?),
Figs. 1781, 1782,
resting on a per
forated brass plate,
and held by a single
screw. In conse-
quence of the sur-
faces of this valve
being pliant and a
yielding through. Fig. 178]. Fig. 1782.
out, a piece of sand or gravel, even if it could so rest
on one of the light divisions of brass beneath the
leather so as to be pressed upon by the leather, would
so imbed itself in the leather as not to impede the
action of the valve.4 At f p is the force-pipe.
We have already referred to the loss of power
occasioned by the intermittent motion of the water
in the suction and force-pipes. An uninterrupted flow



a? .67“ -


(3) In the experiments with Letestu’s forcing-pump, it did not
lift its own water, but was fixed in a. cistern into which the water
was poured from buckets, and thence flowed into the barrel from
the top as the piston was raised.
(4) ‘In the Jury Report is an account of some experiments with
suction~pipes covered with gravel and sand.
PUMP.
‘1521
is produced by the arrange-
ment shown in Fig. 1783,
which is a very old form of
pump. On referring to the
force-pump, Fig. 1771, it will
be seen, that in the upward
motion of the piston water
is drawn up, and in its down-
ward motion it is forced up ;
but as the piston contains no
valve, it was thought that
its upper surface might be
made to raise or propel water
as well as the lower: so that
while the lower surface was
engaged in drawing water,
Fic-1783- the upper surface might be
forcing it, and vice verso’. These effects are produced
by the arrangement shown in Fig. 1783. When the
piston ascends, as shown in the figure, the valves
121 122 are opened, and water is drawn up the tube T
by the lower surface of the piston, and forced up 'r by
its upper Surface. When, on the contrary, the piston
descends, water is drawn by the upper surface of the
piston through the valve 223, and forced by the lower
surface of the piston through 04. These double-action


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pumps are seldom used on account of the number of '
valves required, and their liability to get out of order;
so that when a constant stream is required, 2 pumps
are used, so arranged with reference to the moving
power, that while the piston of one is ascending the
piston of the other is descending. Four pumps are
sometimes made to work together, in which case,
while one piston is at the top of its stroke, the fourth
is at the bottom, the second at a quarter, and the
third at a half or three-quarter stroke.
In one description of the
Fire Engine [see Finns], a
force-pump without a piston
is described. Astill simpler
form is shown in Fig. 17 841,
in which Z! is a lever mov-
ing round c as a centre ; the
' end 012 works in a box I;
immersed in water, of which
20 is the level. When la
is pulled to the left, the end
c6 forces the water from
the box up the pipe 12, and
through the valve 22, where
it is kept by the descent of the valve. The water
enters the box by the aperture a.
A continuous stream is also produced by what is
called the rotatory or ccntrzfugal pump. The history
of this form of pump has been traced back for up
wards of a century.1 In its most general form, water,

Fig. 1784.

(1) In the Practical Blechanic’s Journal for September, 1851, is
“ A Historical Review of the Centrifugal Pump.” Although the
list of pumps here given is by no means complete, it is of great
value. The following are the dates of the inventions, and the
names of the inventors. 1732, Le Demcur. Date unknown——
Inverted Barker's Mill. 1816, Jorge—West. 1818, Massachu-
setts Pump. 1830, the same improved. 1831, Blake. 1339,

admitted at the axis of a hollow wheel traversed by
vanes, and made to revolve rapidly, is expelled at its
circumference. The pipe by which the water reaches
the axis of the wheel, or the reservoir in which the
wheel is immersed, becomes under these circumstances
a suction-pipe; and if the reservoir into which the
water is received from the periphery of the wheel be
closed, and a pipe be carried from it upwards, such
pipe becomes a force-pipe. Although, at the time of
the Great Exhibition, rotatory pumps were regarded,
in England at least, as novelties, they had long been
known in France and America, and a very slight
research into books on hydraulic machinery was
suificient to make known many varieties of this
form of pump, all agreeing, more or less, with the
general description just given. For example, Fig.
1785 is a vertical section of the Massachusetts
pump in the plane of motion of the elevating blades,
and Fig. 1786 is a vertical transverse section of the
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Fig. 1785.
same. This form of pump resembles the ordinary
blowing fan: it consists of a short horizontal shaft,


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Fig. 1786.
carrying a square boss with A eccentric blades set
eccentrlcally within a metal case, from which proceeds
Andrews. 1841, Whitelaw. 1844, Gwynne. 1845, Bessemer.
1846, Andrews’ Improved—Whitelaw’s Improved. 1846, Von
Schmidt. 1848, Appold. 1849, Bessemer’s Improved. 1850-1,
Gwynne’s Balanced Centrifugal Pump. 1850-1, Bessemer.

522
PUMP.
an upright discharging passage F. The apparatus is
sunk below the level of the water which is to be lifted,
and the vanes being made to revolve by means of the
external bevel wheels, the water is sucked in at the
central aperture 0, and being impelled forwards by the
revolving blades, is finally discharged by the centri-
fugal force through the passage 13‘. It appears, from
Fig. 17 86, that the vanes are tapered towards their
outer extremities.
Fig. 1787 is a form of pump described in several
French works. It consists of a wheel 0 o, mounted


Fig 1787.
on an axis a, which corresponds with its centre. This
wheel is enclosed within a hollow box or reservoir 11. n,
and is furnished with 4 slots, in which the tongues e e
are made to slide in by being pressed against the
interior surface of the box or case, and to slide out
by the pressure of a spring within the wheel. These
tongues divide the space RB. into ll compartments.
This space is not altogether concentric with o 0, but
at one part, to the left, it is brought nearer to the
centre a, so that when the wheel 0 revolves, the
tongues ee are forced inwards in passing this con-
tracted part, the effect of which is to vary the capa-
city-of the 41 compartments. There are 2 openings
in the box R 1a to which pipes are attached, one corre-
sponding with the suction-pipe, and the other with
(the force-pipe of the common force-pump. When, by
the rotation of the wheel 0 C, and the projection of
‘2 of the tongues, one of the compartments surrounding
it becomes enlarged in size, such compartment is at
that very moment in communication with the opening
leading into the suction-pipe; water, therefore, rises
in this pipe and entirely fills the compartment just
when it has attained its greatest capacity. As the
wheel turns round, and this compartment begins to be
contracted, it communicates with the force-pipe by
the second opening, and discharges its water accord-
ingly. In this way, by the continued motion of the
wheel, water rises into each compartment just as it
attains its greatest capacity, and is discharged there-
from into the force-pipe all the time that its capacity
is being diminished; and as these two actions are
continuous, a constant stream of water is discharged
above.
some old forms of rotatory pump, described by
Ramelli and others, are represented in the 3 follow-
ing figures. In Fig. 1788, a wheel w, with 3 spiral
wings, ss'-s2, revolves round a centre 0. When a
‘ascends towards r the water between s and r is forced

up into the pipe 12, and is prevented from returning
by the valve 22, the rod .
r rising between the
guide-rollers g g as s
advances to r, for the
purpose of preventing
the water from getting
through at r. The next
wing, 8', produces a
similar effect, and car-
ries the water above its
natural level to w to the
Pipe 11-
In Fig. 1789 there
are 2 revolving wheels, '
w w’, working into each
other, and fitting close -
to the elliptical cistern Fz'y- 1788-
0 c’. The water which rises through the pipe 19 into
0 is forced by these
wheels round the outer
teeth, and so up the
pipe 12'. A pump of
this kind, with only
one wheel, is described
in Nic/zolswz’s Jom'nal,
vol. viii.
In Fig. 17 90 the
same effect is produced
by a wheel w, fur-
nished with a number
of vanes 22 c, which fall
down on the circum-
ference of the wheel
at the side, and resume
their other position by
the action of a spring .9 attached to each of them:
hence they force the water up
from p to 12'.
Two centrifugal pumps in
the Great Exhibition, one by
Mr. Appold and the other by
Mr. Gwynne, excited much at-

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Fig. 1789.














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sists of a. revolving fan 1:‘, Figs. ;pi 1791, 1792, 1 foot in diameter,
and 3 inches wide, formed of
2 sheets of copper or sheet- fi iron bevelled outwards towards ' the centre like shallow dishes.
There is an opening one-half
the total diameter in the centre
of each side, for the admission of the water, and
a central division-plate, extending to the circum-
ference, to give a direction to the 2 streams of water,
and for the convenience of fixing to the shaft s.
Between the outer discs and the centre plate are 6
arms or blades passed through slots in the centre
plate, and soldered to the inner surfaces of the outer
disks. These arms are curved backwards, and termi-
nate nearly in a tangent to the circumference. The
Fig. i790
PUMP.
52$
revolving fan is fixed to the end of the driving shaft
s, which passes through a stuffing box in the side of

the casing, and the fan is made to work between
2 circular checks 0 c, as close to them as, possible
without actually touching, the object of these
cheeks being to shield the outer revolving surfaces
from the water, but at the same time to allow a free



ingress for the water at the centre. To facilitate the
escape of the discharged water, a large space ss is
left round the circumference of the fan. The water
to be raised is, as already stated, admitted through
the central openings in the outer disks, and the fan
being made to revolve with considerable velocity, the
water is discharged by the centrifugal force through
the openings in the circumference, and so up the
force'pipe to the discharge opening.
In Mr. Gwynne’s pump, there is one straight radial
arm, as shown in Figs. 1793, 17 94:, which represent a
longitudinal and a transverse section. The arms are
also straight in Mr. Bessemer’s pump, shown in ver-
tical section, Fig. 17 95, and plan, Fig. 1796.
A number of experiments were tried at the Great
Exhibition on the working power of these pumps.
The results are given in the Jury Report in a tabular
form, together with the following remarks :-—“ The
greatest economy of power, in such a pump, may be
expected to be attained when there is the least pos-

sible loss of the vis viva of the water in its access to
the wheel, and when there remains the least possible
vis viva in it when it leaves it. For if there be any
loss of the vis viva of the water in its ingress to the


o
1.57),
“gem/MM”
as: mxéxad "‘_'Q“_'
2'." . .
.’ :“Q
.l f
1 "\
, ,\§_ ,4 m


v4: -—__'
"fl-
\\\
__\.






mi v l
h &\\\c54 ' if.‘ \ ‘ *‘a
“ e

l
'I'Ilflqlfll 41‘!
:ra/lluz/Aaaalxlll
“a ' 1 ‘
J .--.i __.-._~
Fig. 1793. Fig. 1794.
pump which might have been avoided, it is evident
that power must have been expended unnecessarily in
producing that vis viva. And in like manner, if any
vis viva remain unnecessarily in the water when it
leaves the wheel, it is evident that the power by which
that vis viva was created might have been saved. The
expedients by which the water may be brought to the
wheel with the least loss of vis viva are common to
this and to other hydraulic machines; those by which
it enters and is delivered from the wheel are peculiar
to the centrifugal pump. If the vanes be straight
(as at B c, Fig. 17 97), it is evident that whatever may
be the velocity of the water in the direction of a
v p _ “4/11”!

Idvldvllllu




.._.___.__

(.fi'lfffmzzzr/l/I)
1110:I101/1105541111III/IIIAYH-GTW

‘is PWR\\\ . t m“ llq x. _
l‘ V y 7 a?” Ml is
‘a i ,r'"; it
s 2...: " q": I I l
v“€\\z'\;f{\_\=s\\,\l\\\ am . ¥~\“\S““§\\“x§\ ,
\ 1 &
II
r “\
wmw
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WIN/IMII‘J}
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Fig. 1795.
radius, when it leaves the wheel, its velocity in the
direction of a tangent will be that of‘ the circumfe:
rence of the wheel, so that the greater the velocity of
the wheel the greater will be the amount of vis viva
remaining in the water when discharged, and the
greater the amount of power uselessly expended to
create that vis viva. If, however, the vanes be curved
backwards (as at A, Fig. 17 97 ),‘as regards the motion
of the wheel, so as to have nearly the direction of a
tangent to the circumference of the wheel at the points
where they intersect it, then the velocity due to the
centrifugal force of the water carrying it over the sur-
face of the vane in the opposite direction to that in
which the wheel is moving, and nearly in the direction
of a tangent to the circumference, will,-—if this velo-
city of the water over the vane in the one direction
be equal to that in which the vane is itself moving in
the other—~produce a state of absolute rest in the
Ill/11,,
I
524!
PUMP.
water, and entire exhaustion of vis viva. And in what-
; ever degree the equality
'4 of these two motions—of
the water in one direction
. over the vane, and of the
vane itself in the oppo-
* site direction—is attained,
in that same degree will
the water be delivered in a state
approaching to one of rest.
“ With regard to the admis-
sion of- water to the wheel, it is
obvious that it should pass directly
from the suction-pipe into the
wheel without ‘the intervention of
any reservoir in which the vis
viva of the influent stream,--com-
municated in the act of rising
- through the pipe--may expend
Fla-1797. itself, and that such space should
be allowed at the centre as not to alter the dimen-
sions of the influent stream. It would further
seem expedient, by means of properly constructed
channels, to divide the water into separate streams,
and to give to these divergent streams such curva-
tures as would facilitate their entrance upon the
channels formed by the vanes; as in the turbine. It
is obvious that the tendency of the centrifugal force
continually to increase the velocity of the water over
the vanes as it recedes from the centre, cannot take
efiect in respect to all the particles of water in the
same section, unless the sections of the channels
diminish. If they do not, some of the particles of
water in each section must be continually retarded,
and power he uselessly expended in producing this
retardation; whilst the current cannot but sufier
from it a disturbance destructive of its vis viva. This
diminution of the sections of the channels might pro-
bably best be efiected by giving to the sides of the
wheel the forms of conical disks; an expedient which
is adopted in Mr. Lloyd’s blowing machines and in
Mr. Bessemer’s centrifugal pump. The communica-
tion of motion to the water of the reservoir in which
the wheel revolves and into which the water is dis-
charged, should by every practicable expedient be
avoided; and for this object the water should be kept
as much as possible from the sides of the wheel. This
is effected in Mr. Appold’s pump by fixing the wheel
between two cheeks which project from opposite sides
of the reservoir. The velocity with which the wheel
must be driven depends upon the height to which the
water is to be raised. Beyond a certain height this
velocity is practically unattainable. But long before
this limit is reached, it becomes inconsistent with an


' economical application of the power which drives the
pump. It is probably therefore only in comparatively
small lifts, where a large quantity of water is to be
discharged, that the centrifugal pump will be found
useful.”
The experiments tried with Appold’s pump at the
Great Exhibition were for the purpose of ascertaining
the per-centage of useful effect yielded by it when

raising water to different heights. The power em-
ployed in each experiment was measured by means of
Moria’s dyaamomezfer,‘ arranged as follows :--The
driving strap from the steam-engine was passed over
the first pulley of the dynamometer, and the pump
was driven from the second pulley running loose on
the same shaft and connected to the first by means of
a spring, through which all the power was transmitted:
the amount of the driving power was therefore indi-
cated by the extent to which the spring was bent,
and this was shown by a continuous pencil mark upon
a paper cylinder connected to the instrument, and
from which the actual tension of the driving strap at all
periods of the experiment was accurately ascertained.
By this means the following results were obtained :—
APPoLD’s CENTRIFUGAL PUMP, with curved arm. A, Fig. 1797.
Per-centage Revolution of Velocity of
of effect to Height of Discharge per pump per circum-
power. lift. minute. minute. ference.
Feet Gallon. Feet per min.
59 8.2 2,100 828 2,601
65 9.0 1,664 620 1,948
65 18.8 1,164 792 2,488
68 -. 19.4 1,236 788 2,476
46 ... 27.6 681 876 2,7151
With straight inclined arms. 13, Fig. 1797.
43 18.0 736 690 2,168
With straight radial arms. 0, Fig. 1797.
24 ... 18.0 ‘174 720 2,262
At a meeting of the Institution of Mechanical
Engineers, held at Birmingham 28th June, 1852, Mr.
Appold made some interesting statements respecting
centrifugal pumps. He illustrated the superior ac-
tion of oblique arms, 13, Fig. 1797, to radial arms, 0,
Fig. 1797, by supposing a vertical arm an, Fig. 1798,
to move in a straight line to c 1), instead of moving
round in a circle in the pump, E
and the body A, representing a
particle of water, would then be
simply moved along to c with the
arm, without having any tendency
to be propelled outwards along the
arm to B. But if an oblique arm
A111 is employed, moving in the same direction as
before to the position on, it propels the particle A
outwards towards 13, having an inclined-plane action
to push the particles of water outwards from the
centre towards the circumference. When this was
applied to a circular motion, and the direction A c
bent into a circle, the inclined arm A It became
curved in a spiral direction like the arms in the pump.
The comparative value of the different forms of arms
proved by the experiments at the Great Exhibition,
and as shown in the above table, give a duty of 68 per
cent. for curved arms, 413 per cent. for inclined arms,
and only 24k per cent. for radial arms. It is stated
that the other centrifugal pumps in the Exhibition
which had straight arms did not give a higher duty
than 24 per cent.2 With respect to the velocity of


(1) This instrument is described in our INTRODUCTORY Essay,
page cliii. Figs. Ixxii—lxxiv.
(2) Although Mr. Appold appears to have been the first practical
centrifugal pump maker who fully appreciated the superior value
of curved vanes over straight ones, it appears that the curved
form was adopted in some pumps erected in the United States of
America about 1839 ; but it is a remarkable fact that curved vanes
PUMP—PUNCH.
525
the circumference of the wheel, this must be constant
for all sizes of pump for the same height of lift: that
is, a pump 1 inch diameter must make 12 times the
number of revolutions per minute compared with one
12 inches in diameter, and both pumps will then
raise the water to the same height, but the quantity
of water delivered will be 14:4: times greater in the
12-inch pump, being in proportion to the area of the
discharging orifices at the circumference, or the square
of the diameter, when the proportion of breadth was
kept the same, namely ith of the diameter in each
case. A small pump 1 inch in diameter gave propor-
tionate results with a pump 12 inches in diameter,
the former discharged 10 gallons of water per minute
and the latter 1,440, and consequently it is assumed
that a wheel 10 feet in diameter would discharge
1414i,000 gallons per minute. A velocity of the cir-
cumference of 500 feet per minute raised the water
1 foot high, and maintained it at that level without
discharging any; and a double velocity raised the
water to 4: times the height as the centrifugal force
was proportionate to the square of the velocity;
consequently
Feet per min. ft.
500 raised the water 1 without discharge.
1,000 ,, 4 ,,
2,000 ,, 10 ,,
4,000 ,, e4. ,,
The greatest height to which the water had been
raised without discharge, in the experiments with the
1-foot pump was 67 '7 feet with a velocity of 40,153
feet per minute, being rather less than the calculated
height. A velocity of 1,128 feet per minute raised
the water 5% feet without any discharge, and the
maximum effect from the power employed in raising
to the same height 512- feet, was obtained at the
velocity of 1,678 feet per minute, giving a discharge
of 1,1100 gallons per minute from the 1-foot wheel.
The additional velocity required to effect the discharge
is 550 feet per minute; or the velocity required to
eii’ect a discharge of 1,400 gallons per minute, through
a 1-foot pump, working at a dead level without any
height of lift; so that adding this number in each
case to the velocity given above at which no dis-
charge takes place, the following velocities are ob-
tained for the maximum effect to be produced in
each case :—-
Feet per min. ft.
1,050 velocity for 1 height of lift.
1,550 ,, 4 ,,
2,550 ,, 16 ,,
4,550 ,, 64 ,,
Or in general terms, the velocity in feet per minute

were in most if not all cases rejected for straight ones. In a
memoir by M. Ch. Combes, “ Sur les Roues de Reaction,” read
before the Academy of Sciences at Paris on the 23d July, 1838,
“the theory of the centrifugal ventilator is discussed, and its
obvious relations to the theory of the centrifugal pump are pointed
out. The curved form proper to the vanes is insisted on in this
paper, and its theory investigated.” In 1838-9, M. Combos appears
to have taken out a Brcvet d’z'noention for a centrifugal pump, a
model of which still exists in the collection of the “ Ecole Nation-
ale des Mines,” at Paris. In 1843 he published a work, “ Sur les
Roues a réaction on a tuyaux.”

for the circumference of the pump to be driven, to
raise the water to a certain height, is equal to

550 + (500 a/height of us. in feet.)
Mr. Appold considers that when his pump works
at the most effective velocity it yields a duty of 7 0 per
cent. One of the great advantages of a pump of
this kind is the ease and celerity with which it can be
erected; and situations occur where it is highly im-
portant to be able to discharge a very large quantity
of water in a short time. For example, in laying the
foundations of the harbour works at Dover, a large
quantity of water—2,000 to 3,000 gallons per minute
-—was pumped out by one of these pumps, an effect
which could not have been produced in the time by
any other means, in consequence of the difficulty and
delay of fixing ordinary pumps of great capacity. The
centrifugal pump had another important advantage
for such applications from having no valves, which
enabled it to pass large stones, and almost anything
that was not too large to enter between the arms.
The largest pump constructed on the present plan
was erected at Whittlesea Mere for the purpose of
draining. The wheel is ‘1% feet in diameter and its
average velocity is 90 revolutions or 1,250 feet per
minute; it is driven by a double cylinder steam- engine,
with steam A0 lb. per inch, and vacuum 1354b. per
inch; it raises about 15,000 gallons of water per
minute an average height of 4! or 5 feet. The cost of
the engine and pump was about 1,600Z.
The centrifugal pump is more advantageous for low
lifts (below 20 feet) than for high lifts. Its most
advantageous application is as a tidal pump, where the
height of lift is continually varying, because it dis-
charges more water the lower the lift, the pump still
going at the same speed. Valve pumps generally
discharge their cubic contents only, however low the
lift. The centrifugal pump is also a useful adjunct
to a water-wheel, to assist in keeping it at work by
returning a portion of the water when the supply is
short.
PUNCHwPUNCHING MACHINE. In the
ordinary acceptation of the word, a punch is a circular
or a four-sided or other form of chisel, for making a
hole in any thin substance, or for cutting out blacks, as
for buttons, steel pens, and numerous other objects.
Punches may be arranged into two classes, viz. abcplczc
and single. The former are used in pairs, and partake
of the nature of shears. Single punches have usually acute edges with one perpendicular
side: but sometimes the edges are rectan-
gular. The punch is driven through the
material to be cut by the blow of a hammer, If,
and in order to prevent the cutting edge from being injured the material is placed
upon a support of wood, lead, tin, 850. The
gun—punch, Fig. 1799, is made by turning,
as is the case with most circular punches.
It is conical on the outside and nearly
cylindrical within, being a little wider at the top
to allow the waddings to ascend freely and escape


l 1’
F29. 1799.
526
PUNCH—PUNCHING MACHINE.
through the upper opening. When such punches are
of large size, over 2 inches in diameter, they are made
of steel rings attached to iron stems. The punch
used for cutting out wafers is a thin cylinder of steel,
attached to the end of a perforated brass cone with a
cross handle at the top. Lozenges are cut out with
a thin steel cutter fixed to a straight perforated handle
of wood. 5‘ When the disk is the object required, the
punch is always chamfered exteriorly, as then the
edge of the disk is left square, and the external or
wasted part is bruised or bent ; but the punch is made
cylindrical without and conical within when the annulus
or external substance is required to have a keen edge.
And. when pieces, such as washers, or those having
central holes, are required in card or leather, the
punches are sometimes constructed in 2 parts, the
inner being made to fit the outer punch, and their
edges to fall on one plane; so that one blow eifects
the two incisions, and the punches may then be
separated for the removal of the work should it stick
fast between the two parts of the instrument”.]
Various forms of punches are described or referred
to in the course of this work.-—See Conn—(JOINING—
ENVELOPE-FOLDING MACHINE—FLOWERS, ARTIFICIAL
-—CUTLERY——-BUTTON——PEN—NAIL, &c.
Many forms of punch are for the sake of greater
precision in their action furnished with guides. The
punch pliers, Fig. 1800, have a round hollow punch
with acute edges, and are used for making holes in
QEDQP
%
Fig. 1800.
leather straps and thin materials. Some pliers are
made with oval punches ; others square and triangular.
In all such tools the punch closes upon a small block
of ivory or copper, and the material being put between
the punch and the block and pressure applied, it is
cut through without injury to the punch.
The tool shown in Fig. 1801, is of great use in
repairing boilers, and in confined situations where
‘~ larger tools cannot be used, as about
the holds of ships. It consists of a
;;-:;;~,~_;_‘ ~stout piece of wrought-iron about
‘it; 1 inch thick, and about at or 5 inches
It"? wide, thickened at the ends and
bent into the curve shown in the
figure. One extremity is tapped
' for the reception of a coarse screw,
the end of which is formed as a
cylindrical pin or punch. Opposite the punch is a
hole for the reception of a hardened steel ring or
bed punch. When the screw is turned round by a


(1') Holtzapfi‘el, Mechanical Manipulation, v01. ii. The reader
interested in the subject is recommended to study the chapter on
Punches in this admirable work.

lever about 3 feet long, it will make holes as large
as {— inch diameter in plates % inch thick. A similar
tool made of gun-metal, but weighing only a few
ounces, is used for punching the holes in leather
straps, for lacing them together by thongs, or uniting
them by screws and nuts, as in making the endless
bands or belts for driving machinery.
In connexion with punching, the fly-press comes
into prominent importance. This most useful appa-
ratus is employed for cutting out blanks, punching
holes, moulding, stamping, bending dr raising thin
metals into various shapes, impressing others with
devices as in medals and coins; also in the manufac-
ture of encaustic tiles, tesserae, &c., and various
other objects of great commercial importance. The
fly-press is a contrivance for giving a precise and
well-regulated blow to the punch, which is guided by
moving in a slide: the slide gives precision to the
blow, while the required degree of force is imparted
to it by the heavy revolving fly attached to the screw
of the press.2 When the fly-press is used for cutting.
out works it is called a carting-press, to distinguish it
from stamping or coining-presses. The body of the
press 13, Fig. 1802, is a solid massive piece of iron,
attached to a bed or base B’ at right angles to the
screw. The latter is coarse in pitch, and has a


t
\
v‘ 1\ \
.~"i_"<:*/~\>.
'l‘i 1 ilk?) ‘ '/ -.’ 5};


\
. ~-_—- *2‘
, ' ...__...__n-‘..._-m.___‘_'~:‘f* .ig’". s
‘ Ki,‘ -_..-_. __:-_-__:.<..~u_'..~_-___ __ -‘ '
, - . H
l
. .2 r
l
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Fig. 1802.
CUTTING-PRESS.
double or triple square thread, the rise of which is
about 1 to 6 inches in every revolution. The nut of
the screw a is usually of gun-metal, and is fixed in
the upper part or head of the press: the top of the
screw is square or hexagonal, and on it is fitted a
wrought-iron lever with a solid cast-iron ball at each
extremity; the lever and balls forming the 1%, f.
From the lever a handle descends to the level of
the dies, so that while the operator works the press
with his right-hand, his left is at liberty to feed the
press. The punch is usually attached to a square bar
or follower, which fits into an aperture at the bottom
of the screw. A punch is commonly attached by
being fitted into a cavity, and retained by a pin or

(2) This is also the principle of the embossing-press described
under Booxnmmne, Fig. 174.
PUTTY—PYROAOETIC
$97‘
SPIRIT—PYROPHORUS.
side screw; but a die is screwed into the follower.
The bed or bottom die d is held in its proper position
by d screws as passing through as many blocks or
dogs : the screws point in a slightly downward direc-
tion, and by their means the die can be nicely adjusted
so as to correspond accurately with the punch. The
projecting piece 12, called the pallcnofi”, rests nearly in
contact with the die: its oflice is to detach the sheet
of metal from the punch, for after every blow the
punch, being passed through the sheet of metal, ad—
heres to it and raises it: but the punch, being elevated
above the perforation in the puller-0d, is thus released,
and the sheet of metal is readjusted over the die pre-
paratory to another blow.
A puma/ring mac/zinc, as used by engineers, is repre-
sented in our Inrnonucronr Essxv, Fig. xxvII. It
is chiefly used for making the rivet-holes round the
edges of the plates for steam-boilers, tanks, and iron
ships. It is also used for cutting out curvilinear parts
and apertures in boiler work, in which case a series of
holes is made with a round punch, the holes being
run into each other along the line to be cut through.1
PUOZZOLANO. See Mon'rxns and Gnnrnu'rs.
PURPLE OF CASSIUS. See Porrnnr and Pon-
CELAIN. Sncrron IX.
PUTREFAOTION. See F001), PRESERVATION or
--Fnnnnurx'rrou.
PUT'I‘Y. The putty used by glazicrs for fastening
window-glass in the frames, and by carpenters and
others for stopping holes in their work, is a mixture
of whiting and linseed oil. The whiting is dried,
pounded, and sifted, and stirred into a tub containing
the oil. When sufficiently stiff, the mass is taken out,
placed on a board, and worked by hand, more whiting
being added from time to time: it is lastly beaten
with a mallet until it is sufficiently smooth and uni-
form. By exposure to the air it becomes hard and
durable.
PUTTY-POWDEB, an oxide of tin, or of tin and
lead in various proportions, much used in polishing
glass and other hard substances. The best putty-
powder consists of pure oxide of tin; but as the ma-
nufacture of this is difficult, the oxidation is assisted
by the addition of a small quantity of lead, for which
purpose the linings of tea-chests are employed, or an
alloy prepared in ingots by the pewterers, and called
simrfl'. Common putty-powder, of good fair quality,
is prepared from equal parts tin and lead, or tin and
shrulf. The inferior dark-coloured kinds are made
from lead only. Putty-powder is prepared by placing
the metal in an iron muffle kept at a red heat; the
metal fuses, the oxide forms on its surface, and it is
frequently stirred to expose fresh surfaces to the air.
When all the metal has disappeared, the process is at
an end, and the upper part of the oxide sparkles like
particles of incandescent charcoal. The oxide is re-
moved in ladies, and is spread out in iron cooling-
pans. Hard lumps of the oxide are then selected and

(l) The punching-engine, contrived by Messrs. Maudslay, Sons,
8: Field, for manufacturing water-tanks for the Royal Navy, is
engraved and described in Buchanan’s “ Treatise on Mill Work,"
edited by G. Rennie, Esq. RR. S. Other punching-engines are
also figured and described in the same work.
ground dry under a runner, and the powder thus pro-
duced is sifted through lawn. The whitest powder,
if heavy, is generally the purest : some of the common
powders are brown and yellow: those known as grey
patty contain a small portion of ivory-black. The
pure white putty is preferred by opticians, workers in
marble and others: it is the smoothest and most cut-
ting, and answers well as a plate—powder, and for
polishing in general. The putty—powder prepared by
Mr. A. Ross, the optician, for fine optical purposes, is
noticed under Imus.
PYBI'I‘ES. The native bisulphuret of iron strikes
fire with steel, and hence its name, from 1113;), fire,
because, as Pliny supposed, “there was much fire in
it.” Copper pyrites, or memrlz'c, is a bisulphuret of
copper. See InoN—Corrnn.
PYROAOETIC SPIRIT. When anhydrous me-
tallic acetates are subjected to destructive distillation,
they yield, among other products, an inflammable
volatile liquid, which has been named acetone or gay/ro—
acctz'c spirit. It is readily prepared by distilling dried
acetate of lead in a large earthen or coated glass
retort, gradually raised to redness. A receiver, kept
cold with abundance of cold water, is adapted to the
retort. Much gas, chiefly carbonic acid, escapes, and
the volatile spirit is condensed in the receiver. Mi-
nutely divided metallic lead is left in the retort, and
this sometimes acts as a rrnornonus. The acetone
is slightly contaminated with tar. It is purified by
being saturated with carbonate of potash, and it is
afterwards rectified from chloride of calcium in a
water bath. The pure acetone is a colourless limpid
liquid of peculiar odour: its density is .7 92 : it boils
at 132°: it is very inflammable, and burns with a
bright flame: it mixes in all proportions with water,
alcohol, and ether. It consists of (331130, and is
formed by the conversion of acetic acid into acetone
and carbonic acid. [See ACETIC Aorn] Acetone is
also produced in the destructive distillation of citric
acid, and may be procured from sugar, starch, and
gum, by distillation in an iron bottle, with powdered
quick-lime. In this case it is accompanied by an oily,
volatile liquid, separable by water, in which it is
insoluble : it is termed mctacctone, and contains
OfiHfiO.
PYROLIGNEOUS ACID, one of the products of
the destructive distillation of wood. These products
will be considered together underWoon, Drsrrnnarron
or.
PYROMETER. See Tnnnnonn'rnn.
PYBOPHOBUS, a name applied to those powders
which ignite spontaneously on exposure to the air.
A very good pyrophorus can be made by means of the
tartrate of lead, formed by adding tartaric acid or a
tartrate to a solution of nitrate or acetate of lead.
This tartrate is a white crystalline powder nearly in-
soluble. When it is raised to a dull-red heat in a glass
tube it becomes brown, and in this state forms a py—
rophorus, immediately igniting on being shaken out
into the air. This property is to be referred to the
rapid oxidation of the minutely divided metallic lead.
Hombcrfs pyrophorus is formed by carbonizing, in an

528
QUARTZ—QUASSIA—QUEROITRON—QUININE.
open pan, a mixture of dried alum and sugar, and then
heating to redness without contact of air. This com-
pound ignites spontaneously on exposure to air. Finely
divided sulphuret of potassium appears to be the
essential ingredient. _
PYROXILIG SPIRIT. See Woon, DISTILLATION
or.
QUARRY. See Sronn.
QUART, a word applied to the fourth part or
quarter of a gallon.
QUARTATION. See Assaxrne.
QUARTZ is the mineralogical name of a substance
widely diffused throughout nature, as in the numerous
varieties of rock crystal or native oxide of silicium,
siliceous or fiint earth, and silicic acid [see SILIGIUM].
Quartz is one of/ the constituents of granite and of
the older rocks. [See INTRODUCTORY ESSAY, p. lxxix]
It also occurs crystallized and massive. The primary
form of the crystal is a rhomboid, but it is generally
found in hexagonal prisms terminated by hexagonal
pyramids, and when the prism is wanting and both
pyramids are present, the crystal is a dodecahedron
with triangular planes. The cleavage is not usually
traceable by ordinary means, but may often be detected
by heating the crystal and plunging it in water. The
cleavage is parallel to the planes and pyramids of the
ordinary crystal. The fracture is conchoidal, hardness
7 .0; it scratches glass readily, and gives fire when
struck with steel. It becomes positively electrical
when rubbed, and two pieces when rubbed together
in the dark become luminous. It is transparent,
translucent or opaque; the lustre is vitreous or
resinous: the specific gravity 2.69 to 2.81. It is
infusible, insoluble in most acids; but it combines
with the fixed alkalis and produces silicates. [See
GLASS, Sec. 11.]
Pure quartz is colourless, but quartz usually ex-
hibits a great variety of colours. Purple quartz or
amel/zpsl occurs both crystallized and massive: it is
of every shade of purplish violet: it contains alumina
and oxide of manganese. Blue quartz or sidem'te also
occurs crystallized and massive. The Oaz'rugorm or
smo/oy quartz contains a small quantity of bitumen.
Greeu quartz is found in Peru in translucent hexa-
gonal prisms. Opaque massive green quartz is called
prase .- -it is found in Saxony. fiy/soprase is an
amorphous quartz of a light green colour, oxide of
nickel being the colouring matter. Yellow quartz,
called Scotch, and Bo/zemz'au 'z‘opaz is of various shades
of yellow. Opaque yellow or ferruginous quartz
contains about 5 per cent. of oxide of iron: it occurs
in various shades of yellow and reddish yellow. Real
quartz, or Composlella lu/aez'ul/a'ue quartz, is of a
yellowish or reddish-brown.
For different varieties of amorphous quartz we’
must refer to AGATE—FLINT— OPAL—JASPER, &c.
QUASSIA: The bark of the Q. simaroula, a tro-
pical tree, used in medicine, contains a volatile oil,
bitter extract, traces of gallic acid and various salts.
The Q. ewcelsa, also used in medicine, contains a
peculiar bitter extract, named guassz'ue. The medi-
cinal virtues of these trees were first made known by

a negro named Quassy, and the generic term was
given in honour of him. An aqueous solution of
Q. ea‘oelsa, sweetened, makes a good fly-poison, very
much to be preferred to the usual ‘fly-waters which
contain orpiment, the yellow sulphuret of arsenic.
Should children, attracted by its sweetness, drink the
latter they would be poisoned: but they may drink
the quassia water with impunity.
QUERCITRON, the bark of the guerous uz'gra, or
lz'uelorz'a, or yellow oak, a native of North America.
It is prepared for use by taking off the epidermis and
pounding the inner bark in a mill. Its colouring
principle, queroz'lrz'ue, forms pale yellow spangles; it
has a faint acid reaction, is soluble in alcohol, and to
a certain extent in water. A decoction of the bark,
deprived of its tannine by means of glue, produces a
fine yellow upon fabrics mordanted with alum, and
various shades of olive with iron mordants. It is
much used in calico-printing.
QUIGKLIME. See LIME.
QUICKSILVER. See MERCURY.
QUILL. See PEN.
QUININE, a vegeto-alkali obtained from yellow
bark, as oz'uolzouz'a is from pale bark. [See BARK]
The valuable medicinal properties of the Peruvian
barks are due to these vegeto-alkalis. They are
associated in the bark with sulphuric and Male acids.
Pale bark, or cz'uc/zoua couelamz'uea, contains most'
cinchona; and yellow bark, or 0. eortlzj'olz'a, most
quinia. Both are contained in C’. oblougg'folz'a.
There are various methods of preparing cinchonia
and quinia. The simplest is to add a slight excess of
hydrate of lime to a strong decoction of the ground
bark in acidulated water; to wash the precipitate and
boil it in alcohol. The solution filtered while hot
deposits vegeto-alkali on cooling. When both bases
are present they may be separated by converting them
into sulphates, the salt of quinia being the less
soluble of the two crystallizes first and may be
separated.
Ginchonia (320 E12 NO, crystallizes in small, brilliant,
transparent , four-sided prisms. It dissolves slightly
in water, but readily in boiling.alcohol ; it has little
taste, although its salts are excessively bitter. It
acts as a powerful base, completely neutralizing acids
and forming crystallizable salts. Quinia or quinine
C20 H12 N02, resembles cinchonia in many particulars:
but it does not crystallize so readily: it is more
soluble in water and its taste is intensely bitter.
Sulphate of quinine, as mentioned under BARK, is
largely manufactured for medicinal use: it crystallizes
in small white needles, and its solubility is increased
by the addition of a small quantity of sulphuric
acid.
The refuse or mother liquor of the quinine manu-
facturers contains amorphous guz'uz'ue, also called alzz'u-
oz'clz'ue or guz'uoz'rlz'ue. It is a yellow, or brown resin-
like mass, insoluble in water, but freely soluble in
alcohol and ether, as also in dilute acids. It is said
to be identical in composition with quinine; if so, it
may bear to quinine the same relation, that uncrys-
tallizable syrup does to ordinary sugar, it being pro-
RAIN-GAUGE.
529
duced from quinine by the heat employed in the
preparation.1
RADIATION. See HEAT.
RAILWAY. See Roan.
RAIN-GAUGE. The quantity of rain which falls
at different times and in different places is very
variable, although the mean annual quantity is toler-
ably constant for the same locality. Instruments
called plum'ometers or min-gauges have been contrived
for measuring the quantity which falls on a given
spot in a given time. The simplest form of rain-gauge
is a funnel 3 or 4: inches high, Fig. 1803, the mouth
having an area of 100 square inches, placed in a
large bottle, and exposed in an open place to the
weather. After each considerable fall of rain, the




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Fig. 1804.
Fig. 1803.
quantity of water collected in the bottle is to be
measured by a glass jar, Fig. 180%, divided into
inches and parts. In such a case the mouth of the
funnel evidently represents a portion of ground;
and the water collected and measured is the depth
of rain which would cover the ground at and about
the observed spot if the ground were horizontal,
and the water could neither flow off nor sink into the
soil. By noting down the quantity of rain which
thus falls day by day and year by year, and taking the
average of many years, the mean annual fall of rain is
obtained for the particular place, and by extending
these observations the mean annual fall of rain is
obtained for a district or a kingdom.
A convenient form of rain-gauge consists of a funnel
fixed to the top of a brass or copper cylinder, Fig.
1805, with a glass tube rising from near the bottom
and graduated into inches and tenths of an inch.
The water stands at the same height in the glass
tube as in the cylinder and the height can be read
off from the graduated scale. The cylinder and the
tube are so constructed that the sum of the areas of
their sections is a given part, such as a tenth of the
area of the mouth of the funnel; so that each inch of

(l) Fownes, “Manual of Chemistry.” A full account of the
methods of preparing cinchonia and quinia is given in the fifth
volume of Dumas, Chimie appliquée, 8zc. Large quantities of the
sulphate of quinine were formerly manufactured at Paris for
medicinal use, but of late years the trade has been extended to
other countries. Probably the largest makers in the world are
Messrs. Zimmer of Frankfort, who supply the greater part of
Russia, Austria, and Prussia, with this article. Messrs Howard
and Kent of Stratford, are probably the largest manufacturers in
Great Britain. The retail price of sulphate of quinine is about
12s. per ounce.
VOL. II.

water in the tube is equal to the tenth of an inch of
water in the cylinder. A
stopcock is added for draw-
ing oii' the water from the
cylinder after each observa-
_~_._,, . ~ . :1
. ;fl'


1"-


tion. Some years ago Mr. Phil-
i
i
lips submitted to the British - “l
Association a rain-gauge con- , l
structed so as to show the 1
quantity of rain from each of
the four principal quarters of
the horizon. Self-registering
gauges are constructed on
the principle explained under ANEMoMnTnn, Fig. 48. '
The rain-gauge should be
placed in an exposed situa
tion, if possible at a distance from buildings and trees.
The quantity of water in the gauge should be observed
at least twice a day in rainy weather. A less fre~
quent observation may lead to error in consequence
of the rapid evaporation of water. The gauge should
also be as near the surface of the ground as possible;
for it appears that the gauge indicates different quan-
tities of rain as falling in the same locality according
to the different heights at which it is placed.- Thus
the annual depth'of rain at the top of Westminster
Abbey was found to be 12 T‘? inches; on the top of a
house 16 feet lower down it was 18 TLC-inches; and on
the ground in the garden of the house it was 22 T66
inches. '
‘ Mr. Thom’s rain-gauge consists of a cylinder 2 feet
long and 7 inches in diameter, sunk in the earth until
the mouth of the funnel, which receives the rain, is
on a level with the surrounding ground. Into this
cylinder is put a float with a graduated rod attached
to it, the float and rod moving up and down as the
water rises or falls in the cylinder. There is a thin
brass bar fixed within the funnel, about % inch under
its mouth, with an aperture in the middle just large
enough to allow the scale to move easily through it.
The upper side of this cross-bar is brought to a fine
edge, so as to cut but not obstruct the drops
which may alight on it. There is an aperture also
in the bottom of the funnel, through which the water
must pass into the cylinder, and through which also
the scale must move; but this aperture is not larger


rennin-r “1am “



Fig 1805.
‘than will allow the scale to move through it freely.
. The cylinder is firmly fixed in a large flat stone, level
with the surface of the ground. In the stone, a
groove is cut round the gauge to guard it from re-
ceiving rain which may fall on the stone. The adj ust-
ment to zero is performed in the usual way.
Mr. James Johnston described a rain~gauge so con-
structed, that the receiving-funnel or orifice, at which
the rain enters, is always kept at right angles to the
falling rain. By the action of the wind on a large
vane, the whole gauge is turned round on a pivot until
the front of the gauge faces the wind, and by the
action of the wind on another vane attached to the
receiving-funnel, the mouth of the funnel is moved
in 1a
530
RAIN- GAUGE—~RAISED WORKS IN METAL.
towards a perpendicular position, according to the
strength of the wind. The receiving-funnel and vane
attached to it are balanced with counterpoise weights
in such a manner, that the wind, in moving them, has as
much weight to remove from a perpendicular position,
in proportion to their bulk, as it has when moving
an ordinary sized drop of rain from the same position:
by this means, the mouth of the gauge is kept at right
angles to the falling rain} .
In the year 1844:, Mr. Ronalds, in his Report on
the Kew Observatory, described a Rain and Vapour-
gauge which indicated a mean result arising from the
quantity of water which may have fallen between any
two given periods, minus the quantity of vapour
which has arisen in the same time (and vice verse’) on
and from a circular plane of one foot in diameter.
AA, Fig. 1806, is a cylindrical vessel of zinc of the
internal diameter of one foot; B is another cylindrical



Fzg. 1806.
vessel attached to A, and communicating with it by a
small pipe 6 ,- c is a glass vessel standing in B, and
having a small perforation near its feet; 1) D is a
circular plate of brass firmly screwed to a cap 0, and
d’ al'vis a copper plate, also attached to the cap of o; E
and F are cocks fixed upon D, at a distance of about
a inch from each other; e is a pulley upon an arbor,
running in centres opposite to each other in the sup-
ports 12 and F; the centres are jewelled, and the
carefully-turned pivots of the arbor are of platinum;
H is an index carried by e, and I I I is the scale
screwed upon 15‘ ; K is a silken thread passing round
a groove in G, descending through a hole in D, and
suspending a light copper-covered dish I; M is
another silk thread passing in the contrary direction
round another groove in e, and suspending a weight N,
which is somewhat lighter ; P is a glass shade placed
“upon 1) D. This arrangement is an application of the
principle of the wheel barometer. If a quantity of
Water be poured into A, exactly suificient to bring
the index n to a given point, and if afterwards any
addition he made to that quantity by means of rain,
the index will point out the increase upon the multi-
, plying scale I; or if any diminution of that quantity
should be occasioned by evaporation, the loss will
also be pointed out by the motion of the index in the

(1) British Association Report, Vol. x.

contrary direction. The index is brought to zero
every day at sunset by the addition to or subtraction
of water in A, and the mean results of deposition and
evaporation for the preceding 24 hours are observed.
A small reservoir is placed near with a pipe and cock
for supplying water. The instrument is fixed upon a
stand at about 2 feet above the leaden roof of the ob-
servatory. It would, however, be more properly
situated if the cylinders A and B were sunk in the neigh-
bouring earth. The use of the plate (Z’ J’, and of
the glass shade P, is to exclude rain from B, and
for protection. If it were required to be used as a
rain-gauge only, a funnel might be fitted upon A; if
for avapour-gauge only, the whole might be protected
from rain by a roof placed some feet above it.
RAISED WORKS IN METAL. The malleability
of several of the ductile metals and alloys is illustrated
in a remarkable manner in the production of various
well-known articles, such as tea-pots, coffee-pots,
covers of cups and vessels, the bell mouths of musical
instruments, extinguishers, thimbles, &c. Circular
works in thin metal are rapidly formed on a turning
lathe, by the process of what is called “ spinning or
burnishing to form,” or by raising by the hammer, or
pressing between dies. Fig. 1807 will illustrate the
method .of spinning the body of a Britannia metal
tea-pot from a complete disk of metal. The disk d d


Fig. 1807.
is pinched by the fixed centre screw 8 of the lathe,
between two flat surfaces of wood man, one of which
m, is a mould or chuck turned to the form of the
lower part of the tea-pot ; by which arrangement m,
03d, and w, revolve with the mandrel. A burnisher
6, resting against a pin in the lathe-rest is now applied
near the centre of the metal, and a wooden rod 9"
being held on the opposite side to support the edge,
the metal is rapidly bent or swaged through the suc~
cessive forms 1, 2, 3, 4, so as to fit close against the
curved face of the block and to extend up its cylindri-
cal edge. The 5 ‘I _
mould m is now 6 '
removed, and in "- %/%


itsplace isscrewed ' % $0“
on a cylindrical '
block 0, Fig. 1808,
of the diameter-of
the intended aperture or month of the tea-pot.


Fig. 1808.
One
_ of the numerous forms of burnishers employed in
RAISED WORKS IN METAL.
.531
this kind of work is selected; its surface is slightly
greased, and is applied in conjunction with the hooked
stick la, to force the metal gradually inwards, as
shown at 5, 6, 7, and also to curl up the hollow
head which stifi’ens the mouth of the finished vessel
9. In some cases the moulds m are made of the
exact shape of the vessel to be turned : each mould is
made up of a number of pieces, each piece smaller than
the central opening; so that like the parts of a hat-
block [see HAT, Fig. 1130], or of a boot-tree, on
taking out the central block all the other parts are
easily released. It is important during the spinning
to keep the edge exactly concentric and free from
notches : should these occur, the edge is to be touched
with the turning tool. “ The operation,” says Holtzapffel is very pretty and expeditious, and re-
sembles the manipulation of the potter, who forms a
bottle or vase with a close mouth in a manner com-
pletely analogous, although the yielding nature of his
material requires the fingers alone, and neither the
mould, stick, nor burnisher.” 1
The second method of raising works is by means of
the hammer, by the application of circles of blows
applied much in the same order as the burnisher,
which acts by the gradual and continued pressure on
one circle at a time. The metal disk to be raised
must be so selected as to size and thickness that it shall
exactly sutfice for the production of the article, leav_
ing no excess of metal to be cut ofl’, nor deficiency to
be supplied; and the blows of the hammer must be
so managed as to direction and intensity that the
finished work shall be of uniform thickness throughout.
Thus, a hollow ball 6 inches in diameter is made up
of two circular pieces of copper each 7% inches in
diameter: the circumference of the disk measures
22% inches, and this becomes contracted to 18 inches,
or the circumference of the ball, while the original
diameter of the disk, 7% inches, has become extended
to 9 inches, or the girth of the hemisphere. This
double change of dimensions is still more strikingly
illustrated in the spinning of the tea-pot, Fig. 1807 ,
the disk for which was about 1 foot in diameter; this
is contracted to 2 or 3 inches at the month. In the
use of the hammer for works of this kind, care must
be taken to distinguish between opposed or solid blows,
which have the eii'ect of stretching or thinning the
metal; and unopposed or hollow blows, which tend not
to thin the metal but rather to bend and even to
thicken it. Minute directions on these points are
given in Mr. Holtzapffel’s work. I
One of the most remarkable examples of raised
works is the ball and cross of St. Paul’s Cathedral,
London, erected in 1821. The old ball consisted of 16
pieces riveted together: the present ball is of the
same diameter, viz. 6 feet; this was raised in two
pieces only, and may be regarded as a fine example of
the coppersrnith’s art. The metal for the ball was
first thinned and partly formed under the tilt-ham-
mer at the copper mills, and sunk in a concave

(1) In the first volume of the “Mechanical Manipulation” will
be found a very full and highly instructive chapter on “ Works in
sheet metal made by raising."
f
bed; the raising was effected with hammers not
much larger than usual, and the two parts were
riveted together in their place, the joint being con-
cealed by the ornamental band. Most of the work of
the cross and ball is hammered up; the consoles
beneath the ball are of cast gun-metal. The whole
structure is 29 feet high, and the weight of copper 3%
tons. The ball and cross are strengthened by an
inner framing of copper and Wrought iron bars, stays,
bolts, and nuts, extending through the arms and
downwards into the building, thus adding about 2
tons of iron to the load of copper. 38 oz. of gold
were consumed in the gilding. Sugar-pans, stills, &c.,
are made of very large size, on the same principle.
Works, such as jelly-moulds, in which the raising
is very considerable, are produced by the hammer;
but works in less relief, required in considerable num-
bers, are produced by means of dies. For the best
works both the top and bottom dies are usually of
hardened steel, but in some cases the bottom die is
of cast—iron or hard brass : in many cases, the top die
is also of lead, this metal being preferred from the
facility with which it assumes the required shape,
The method of producing figures in relief on buttons
by raising and letting fall a succession ofjoroes, is an
example of this kind of work [see BUTTON, Fig.
393]; we are, however, now referring to larger works
. than buttons, in which cases the sheet of metal to be
raised undergoes the same bendings and stretchings
between the dies as if it were worked by the hammer,
and unless gradually produced the metal will be cut
and rent. This gradual action is brought about by
- placing a number of sheets of metal between the two
parts of the die, and after every blow one piece is
removed from the bottom, and a fresh plate added at
the top: in this way the plates descend and gradually
accommodate themselves to the figure of the die. The
pieces are finished by being struck singly between
dies which exactly correspond. In thus gradually
bringing the plates into the required shape, they may
require annealing from time to time. Thimbles are
raised at 5 or 6 blows between as many pairs of coni-
cal dies, gradually increasing in height, but in passing
from one pair of dies to another the metal requires to
be annealed.
The art of stamping and shaping sheet metal was
made the subject of a patent granted to Mr. T. Foxall
Grifi’ith of Birmingham, Feb. 3, 18416. By the methods
here employed, works with lofty and perpendicular
sides, such as jelly—moulds, are produced by ‘the alterna-
tion of stamping and spinning. By a former patent, the
sheet metal, having been raised as far as possible in
dies by stamping, the shaping was completed by bur—
nishing to form. “ In shaping sheet metal by stamp—
ing, as heretofore practised, the sides of the articles
depend materially for the height of the raising on the
stretching or extending of the metal; _ and, to this
end, the metal at the outer circumference is supported
throughout the process of stamping by a projecting
fianch, which rests horizontally on the upper surface
of the dies, such flanch being progressively reduced,
and the metal thereof stretched or extended, so that,
M M 2
532
RAISED WORK$ 1N METAL.
from the bottom to the upper edge, the thickness of
the metal is brought thinner and thinner, which is
objectionable. At the same time, owing to the severe
treatment to which the sheet metal is thus subjected,
it requires to be more often annealed, in order to pre-
vent its suffering injury by the successive processes
of stamping; and such is the extent to which the
metal is stretched or extended by raising, according
to the old practice, that the disk, or blank of metal
employed for raising a vessel of a few inches diameter
to a considerable extent, is only about g—inch larger
in diameter than the finished vessel raised therefrom
by stamping. Whereas, according to my invention,
the blank or disk of sheet metal used for making any
particular article when the sides thereof are upright,
is of a diameter of about the diameter of the vessel
or article added to the depth of the vessel: thus,
a- w supposing the vessel or
article produced by stamp-
ing in a die be 6 inches
in diameter and 3 inches
deep, then the die or
blank of sheet metal would



.1 K
; U
Fig. 1816.
be about 9 inches diameter, and the article when
stamped therefrom, if it be cut through the sides and
bottom, all parts would be found as nearly as may
be of the same thickness, and that thickness the
thickness of the original sheet metal.”
The vertical sections, marked A to c, Fig. 1810,
represent the several forms given to the sheet of metal
art, Fig. 1809, by employing a die such as that shown in
the same figure, with a second point of hearing at b b;
the successive forces or top dies, that are employed,
being so shaped as to bear only on the bottom of the
vessel as far as the edge I) b, and not over the sloping
sides, the effect of which is to make the edge [2b
perform the office of a draw-plate, such as would be
used for drawing cylindrical tubes. Having been pro-
gressively stamped to the contour of e, the work is
burnished to form on a chuck, Fig. 1811. The work
is again stamped in the second die, Fig. 1812, then
burnished on the second chuck, Fig. 1818 ; struck in
a third die, Fig. 1814, and then burnished on a third
chuck, Fig. 1815, in order to make the metal proceed
through the forms H to L, Fig. 1616. The work is
occasionally annealed as required.
Fluted works, such as M N Fig. 1818, are first
raised nearly as cylinders with bottoms to the shape
of L by the processes just noticed: the burnishing to
form is then discontinued. The flutes are gradually
developed by means of 2 or more pairs of dies and
forces, Fig. 1817. In the first
pair of tools for the object N
the flutes are shallow, and the
die is a little bell-mouthed:
in the second pair the flutes
.M
/ a
ll l U
JV
Fig. 1817. Fig. 1818.
are of the full depth, and as, from the sides being
almost perpendicular, or exactly counterparts of the
burnished object N, the piece, when struck, holds
r/ a


Fig. 1819.
Fig. 1s20.
fast in the die, the latter is perforated, and has a
central rammcr, Fig. 1819, which is raised by a side
lever L to force the finished work out of the die.
That the metal after the raising should be of uni-
form thickness throughout, is thus explained in the
case of the cylindrical vessel already referred to. If
the disk, 9 inches in diameter, by stamping in a die
6 inches in diameter, could have its margin folded up
without puckering, it would have a rim- of 15inch
high, the upper edge being of twice the primary thick-
ness; but the stretching from the dies causes the


height of the sides to become 3 inches, and therefore
Q
RAISED WORKS IN lllETALsflflAlsINSpRAPE-OIL.
the tapering thickness actually produced is gradually
drawn out, as in tube~drawing, to form the increased
height.
So successful is the improved method of raising,
that sheet-iron, which is much less tractable than cop-
per and brass, may be raised. The scaling of the
surface of the iron during the annealing was at first
a difliculty, but this was obviated by annealing after
the manner adopted for malleable iron castings, [see
ANNEALINGJ the annealing mixture preferred being
1 part of pulverized iron ore added to 8 parts of coke
or lime, preference being given to that iron ore which
has been once used for annealing cast-iron. Thus, by
the combined processes of stamping and burnishing
to form and annealing, extinguishers can be raised
from disks of sheet-iron: they are of course without
a seam. The method of stampmg with dies having
the bevelled mouth and shoulder d b, Fig. 1809,
allows vessels to be raised much higher than by any
other method of stamping, even when burnishing to
form is not employed in conjunction with stamping.
The various ornamental details of raised work, such
as escutcheons, concave and convex flutes, are usually
added after the vessel or article has received its gene-


Fig. 1821.
Fig. 1822.
ml form by one or more of the processes described.
If, from the shape of the work, swage tools, such as
those represented in Fig. 1821, cannot be employed
for raising the projecting parts, they are snarled up
by means of a snarling-iron, s, Fig. 1822. One end of
this iron is secured between the jaws of a tail-vice a,
and the other end a is turned up so as to reach any
part of the interior of a vessel. The work is held
firmly in the two hands with the part to be raised or
set-out exactly over the end a: the snarling—iron is
then struck by an assistant with a hammer at it, and
the reaction gives a blow within the vessel which
throws out the metal in the form of the end of the
tool. After the flutes or other ornaments have been
snarled-up, the vessel or other object is filled with a
melted composition of pitch and brick-dust, or some
similar mixture, which, from its adhesive and yielding
nature, forms an excellent
support in the operation of
chasing, leaving both hands
at liberty, one to hold the
punch and the other the
hammer. The punches or
chasing tools, 15, are counter-
part forms of the several
raised parts, and with them the snarled-up parts are
corrected, some portions of the metal being driven in,
while those around rise up from the displacement and
reaction of the pitch. The lower portion of the work


ass
is preserved from injury by being supported on a sand-
bag .9, Fig. 1823.
BAISINS. In the south of Europe and in Egypt,
&c. grapes are allowed to ripen and dry upon the
vine so as to form raisins. The sweet fleshy grapes
which grow upon the sunny sheltered slopes of hills
are preferred. When the fruit is ripe, the grapes are
thinned and the vine is stripped of its leaves. The
sun then completes the saccharification and drives off
the superfluous water. When the bunches are plucked
they are cleaned, dipped for a few seconds in a
boiling lye of wood-ashes and quicklime ; the wrinkled
fruit is then drained and dried, exposed to the sun
upon hurdles for 141 or 15 days. The finest sun raisins
are the plumpest bunches left fully to ripen upon the
vine, after their stalks have been out half through.
An inferior kind of raisins is prepared by drying the
grapes in an oven.
In the year ending 5th Jan. 1853, 261,82410Wt. of
raisins were imported into the United Kingdom, of
which quantity 208,801 cwt. were retained for home
consumption. The import duty is 15.9. per cwt. from
foreign countries, and 7.9. 662. per cwt. from British
possessions.
RAM. See Hrnnosrxrrcs and HYDRODYNAMICS.
RAPE-OIL. rI‘he seeds of Brandon rape and B.
calms are valuable for the large quantity of oil which
they yield by expression. [See OILS and Fars]
B. rapa yields the largest quantity of oil. .73. cam-
pestrz's yields a superior oil known in France as Colzc
oil. Rape~oil is thick, of a yellow colour, and with a
peculiar taste and smell; it concretes into a yellow
mass at about 28°. Its specific gravity is 09167. It
is used in the preparation of woollen goods and of
some kinds of leather. It is much used in'France for
burning in lamps. Colza-oil may be used without
purification, and it is largely employed in lighthouse
lamps. [See LIGHTHOUSE] The common kind of
oil is purified by being agitated with a 200th part of
sulphuric acid, left to repose for 2A hours, when two-
thirds of its bulk of water at 165° are added, and the
mixture stirred until it becomes milky. It is then
kept for 2 or 3 weeks in a room heated to 80°, when
it becomes clear by the deposition of a dark coloured
sediment. It is lastly filtered by being drawn off
into vats the bottoms of which are pierced with holes
stufl’ed with filaments of carded wool or cotton.
Having passed through this filter the oil is fit for use.
The acid may be removed by the addition of powdered
chalk.
RABEFACTION. See AIR-EVAPORATION—-ICE.
BASP. See FILE.
BATAFIA. Certain liqueurs, such as coy/an, car-
agoa, &c., are termed mz‘afias from the custom of
drinking them at the ratification of an agreement.
(Return and fio to make firm.)
RATOBIET-LEVER. See WHEEL.
BAY. See Lren'r.
RAZOR. See CUTLERY. .
REALGAB is the red sulphuret of arsenic As 3,.
See Ansnnrc.
RECEIVER. See Disrrnnarron.
534:
RESINS—RETORT—RHUBARB.
RECOIL ESCAPEMENT.
Fig. 1163.
RECTIFICATION. See DISTILLATION.
RED LEAD. See LEAD.
REED. See WEAVING.
REFINING or PARTING. See AssAYINe—
SILvnn. '
REFLECTION and REFRACTION. See LIGHT.
REFRIGERATION. See BEER—ICE—EVAPORA—
TION.
REGULUS. See ANTIMQNY, vol. i. p. 59, where
this term is explained.
REISNER-WORK. See BUHL—WORK.
RESINS. Resinous substances are found in greater
or less abundance in most plants. Many of them
exude naturally from fissures in the bark or in the
wood, or they are obtained from incisions made in
certain trees and shrubs. As they exude they are
commonly mixed with an essential oil, which either
evaporates on coming in contact with the air, or is
resinified by the action of oxygen. Such mixtures of
volatile or essential oil with resins are sometimes
called balsam [see BALsAM]. When gum is mixed
with resins another class of substances is produced,
called gum-resins. [See GUM-BEsINs]
The resins when pure and free from essential oil
have no odour except when rubbed or heated. Their
colours are pale yellow or brown; they are good
insulators, and become electric by friction. Most of
them are heavier than water and insoluble in that
fluid; they have little or no taste, but those which
have distinctive flavours derive them from minute
portions of some non-resinous body. They are usually
softened or even fused by being boiled in water, and
some of them in such a case pass into hydrates. They
are inflammable, burning in the air with a sooty flame,
and yielding by dry distillation volatile liquids and
inflammable gases. [See GAs]
The natural resins are usually composed of two or
more resinous substances, which may be separated by
the action of alcohol, in which most resins are soluble.
They are also mostly soluble in ether, in sulphuret
of carbon and in the fat and volatile oils. Alcoholic
solutions of many of the resins act the part of feeble
acids, reddening litmus paper, and combining with and
neutralizing acids. These compounds are termed
resz'azales or resin-soaps, and are distinguished from oil-
soaps by not forming a gelatinous emulsion when con-
centrated, and by not being separable from water by
the addition of common salt: they are, however,
detergent and form a lather like common soap. [See
SOAB]
Other resins are indifferent either as an acid or a
base, but there are a few which are regarded as basic.
The resins are thrown down from their alcoholic solu-
tions by the addition of water, the white pulverulent
or curdy precipitate forming the magislery of the old
chemists. The alcoholic solution of the acid resins is
not precipitated by ammonia; but the precipitate
thrown down by the addition of water is soluble in
solution of ammonia. The alcoholic solution of the
indifferent resins is precipitated by ammonia. The
See HOROLOGY,

acid resins may also be distinguished by the crystalline
precipitate produced by the addition of their ammonio-
chloride solutions to nitrate of silver.
Some of the resins dissolve in sulphuric acid with-
out decomposition in the cold, and they are preci-
pitated by the addition of water; but if heat be
applied sulphurous and carbonic acids are disengaged,
and a carbonaceous mass is obtained mingled with
another substance which has been improperly named
m'lz'jlez'al lcmm'vze. The action of nitric acid upon
resins leads to the formation of various new products.
Acetic acid dissolves many of the resins, as does also
muriatic when concentrated.
The resins have been considered as oxides of de-
finite hydrocarbons; but their analysis is very imper-
fect, and will be further noticed under TURPENTINE.
RETORT, avessel of glass, earthenware, porcelain,
clay, iron, &c. in which some kind of distillation is
carried on. Numerous examples of retorts are given
in the course of this work. See GAs--NITnIo-Acn),
Sec.
REVERBERATORY FURNACE. A furnace so
constructed that the flame shall be reflected or rever—
berated upon the bed or sole over which the material
to be operated on by the flame is spread. See COPPER
—IRON-——LEAD, &c.
RHODIUM. See INTRODUCTORY EssAY, page c,
—also, PLATINUM.
RIIUBARB, the root of one of the species of
Rheum, a genus of plants of the natural family of
Polygonaceae. Although rhubarb has been in use for
centuries, the particular species of rheum which yields
it is not known, in consequence of the best, or Turkey
rlmearl, being obtained only by the Russians at
Kiachta from the Chinese. There are six well~marked
varieties in commerce, viz. the Russian, or Turkey,
the Dutch-trimmed, the C/zz'nese, the Himalayan, the
English, and the French. The following description
refers to the first variety, also called .Museom'le, Bo/e-
lzarz'rm, or Siberian rhubarb. The pieces are of various
forms, cylindrical, spherical, flat, or irregular, from 2
to 3 inches long, 1 to 3 broad, and 1 to 3 thick. The
smaller pieces are preferred, the larger ones being
employed for powdering. The holes observed in the
pieces were originally made for suspending them while
drying, or for ascertaining their quality. Other per-
forations are referred to the ravages of a small beetle.
The pieces are covered with a bright yellow-coloured
powder, the result of friction during carriage, or from
the process of rozmez'vzg or shaking them up in a bag
with powdered rhubarb. The odour is strong and
peculiar: when chewed it feels gritty from the pre—
sence‘of numerous raplzz'eles or crystals of oxalate of
lime: it imparts a bright yellow colour to the saliva,
and has a bitter, slightly astringent taste. When
fresh cut, the root has a reddish-yellow hue, with
white lines interspersed. The powder is of a bright
yellow colour verging on red, but it is usually adul-
terated by admixture with an inferior kind. _ Black
and worthless pieces of rhubarb are sometimes dis-
guised by means of yellow ochre; and inferior rhubarb,
or roots cut to resemble the genuine article, are some—
RICE-'T—RICE-PABER.
555
times sprinkled over with powdered turmeric, or dyed
therewith.
Many analyses of rhubarb have been made with the
view to ascertain the source of its medical activity,
which has been successively ascribed to a bitter prin-
ciple, to an organic basis, to an acid, to a gum, to a
resin, and to a colouring matter. Some later re-
searches by Schlossberger and Diipping, show that
there are three resinoid substances in rhubarb, toge-
ther with extractive matter, and the medical virtues
of the root are ascribed not to any one principle, but
to a mixture of several, amongst which are tannin
and gallic acid.
RIBBON, or RIBAND. See WEAVING.
RICE is a valuable cereal grass, Ozyzd sazfz'od, ex-
tensivel y cultivated in India, China, and most eastern
countries ; in the West Indies, Central America, and
the United States, and in some of the southern coun-
tries of Europe. It occupies the same place in
intertropical regions as wheat in the warmer parts of
Europe, and oats and rye in the more northern. The
rice plant appears to be a native of India, where it is
cultivated largely, forming as it does the chief portion
of the food of the inhabitants. The varieties of rice
are innumerable; 4:0 or 50 at least being described.
The rice fields require a large quantity of water,
which is supplied by rain or by irrigation either
from rivers or banks. The best rice fields are exten-
sive open plains intersected by large rivers, so as to
be annually overfiowed by the inundations. Most of ‘
the rice lands of India, however, depend on the rains
only. The different varieties of rice are divided by
Dr. Roxburgh into two kinds; one, named Poonas or
.4800, is sown thick in June or July, and transplanted
in about d0 days, when the plants are from 9 to 18
inches high: the fields are then kept constantly wet;
they are more or less flooded, as some sorts require
very little water, others a great deal. When the
grain is ripe, the water is drained off, and the crop
cut down with the sickle: it is either stacked or trod
out by cattle. The grain is preserved in pits dug in
high ground, and lined with the rice straw. The straw
is stacked for feeding cattle during the hot season.
The second division of cultivated rice is named Pedder
Worloo. Rice is also divided according to the seasons
in which it is reaped, into that which ripens in the
hot weather of spring, in the summer, or in the
winter.
Carolina rice is grown in the marshy grounds of
North and South Carolina. The grains are shorter,
broader, and boil softer than the Patna or best Indian
kind known in this country.
Rice in its natural state, or before it is separated
from the husk, is named paddy. The husk adheres
very closely, and should be separated without break-
ing the grain. In India and China the operation is
performed by beating the grain in a kind of rude
mortar of stone or earthenware with a conical stone
attached to a lever worked by the hand or foot, or
several such levers are worked by arms projecting
from the axis of a water-wheel. A preferable mode
is to employ amill in which the stones are suficiently

removed to detach the shell and not crush the
grain. A sifting and winnowing apparatus is at-
tached to each pair of stones. When the husk is
removed the grain is passed through a wkz'tem'ng
machine, for the purpose of removing the inner cuticle
or red skin. This machine resembles that described
under Banner, Figs, 92, 93, and 941. The rapid motion
of the grains through the machine and the friction to
which they are exposed, cause them to swell and
thus to split the red skin, which flies off in dust
through the perforated revolving case.
The import duty on cleaned rice is 68. per cwt.
from foreign countries, and 6d. from British posses‘
sions; but when rough or in the husk (paddy) the
duty is 78. per quarter for foreign, and 1d. per quarter
for British. These considerable difi'erences in the
amount of duty have led to the practice of import-
ing paddy and cleaning it in this country. The
cleaning apparatus mostly consists of millstones for
breaking the husk, or one millstone and one block
of wood of similar shape, and the dark pellicle is got
rid of by passing the grain between fiat wooden
surfaces covered with sheepskin, so as to produce an
effect similar to that of rubbing the grain between
the palms of the hands. A machine first used in
the United States consists of a long hollow cylinder
of wood with bars projecting from its inner surface:
an internal cylinder is also furnished with bars alter-
nating with the former. The outer cylinder is made
to revolve slowly in one direction, and the inner
cylinder rapidly in the other direction. The machine
is in an inclined position, and is supplied with paddy
from a hopper at the highest part: the friction of
the arms causes the husk to separate, which is blown
away by a current of air as it falls out of the cylinder,
while the rice is collected in a bin.
The following analysis of rice is by Braconnot :—

Carolma. Piedmont.
Water .. . 5.0 7.0
4.8 4.8
Gluten 3 6 3.6
Starch .. 85.07 83.8
Sugar....................... 0.3 0.05
Gum 0.7 0.1
Oil 0.13 0.25
Phosphates 0.4 0.4
100.0 100.0
RICE GLUE, or Jarannsn CEMENT, is made
by mixing rice flour intimately with cold water, and
boiling the mixture. It is white, and dries nearly
transparent, hence its use in making many articles
in paper. When made with a smaller quantity of
water, models, busts, &c., may be formed of it.
RICE PAPER, a name applied to a delicate vege-
table film imported from China in small square pieces
of various colours, and used in the manufacture of
artificial flowers and fancy articles, and also as a
drawing paper for delineating richly-coloured insects
or flowers. This substance is said to be a membrane
of the bread-fruit-tree, and although it resembles an
artificial production, yet on examination by the micro-
scope it is found to consist of “long hexagonal cells,
whose length is parallel to the surface of the film;
536
RIVETTING‘P—ROADS AND RAILROADS.
that these cells are filled with air when the film is in
its usual state; and that from this circumstance it
derives that peculiar softness which renders it so well
adapted for the purposes to which it is applied.” 1
BIFFLER—See FILE.
RIFLE—See GUN.
RINSING MAGHINE~See Cameo PRINTING,
Fig. 4:15.
RIVETTING is the art of joining metal plates
together, and the method of doing so varies with the
article and the uses which it is intended to serve.
Fig. 1824.‘ represents the joint commonly used in
strong iron plate and copper works, boilers, &c. The
272 m ,
r :9 .
Z‘ L‘


F1g.1824. Fig.1825. Fly. 1826. Fig. 1827. Fly. 1828.
edge of one of the sheets of metal having been turned
up, the other edge is placed in the angle, a rivet is
inserted at each end to hold the plates in position,
and the other holes are then punched through the
two thicknesses with the punch
Fig. 1829 on a block of lead.
The head of the rivet is put
within, the metal is flattened
0* around it by placing the small
Ffg' 1829' F59‘ 1830' hole of the rivetting set‘ or punch
for the holes of rivets, Fig. 1830, over the pin of the
rivet, and giving a blow: the rivet is then clenched,
and it is finished to a circular form by the concave
hollow in another rivetting set. If the work does
not admit it being laid on an anvil or stake, a heavy
hammer is held against the head of the rivet to re-
ceive the blow. In large works the holes are punched
before rivetting. In Figs. 18525, 1826, the plates mm
are punched with long mortises, and t t are formed
into tenons which are inserted and rivetted. In
Fig. 1826 the tenons have transverse keys to enable
the parts to be separated. In Fig. 1827 one plate
makes a butt-joint with the other, and is fixed by
screw-bolts s, or by L-shaped rivets. This method
is common for east-iron plates as in stove work.
Fig. 1828 shows the method adopted for strong vessels,
such as steam boilers, in which the plates of wrought-
iron are connected by angle iron rolled for the pur-
pose. “ The rivet-holes are punched in all the 4'.‘
edges by powerful punching engines furnished with
travelling stages and racks, which ensure the holes
being in line, and equidistant, so that the several
parts, when brought together, may exactly corre-
spond. The rivet 2*, which may be compared to
a short stout nail, is made red-hot, and handed by
a boy to the man within the boiler, who drives it into
the hole: he then holds a heavy hammer against its
head, whilst 2 men quickly clench or burr it up from

(1) Brewster, Edinburgh Journal of Science, vol. ii.

without: between the hammering and the contracting
of the metal in cooling, the edges are brought toge-
ther into most intimate and powerful contact. Bolts
and nuts 72 may be used to allow the removal of any
part, as the man-hole of the boiler. For the curved
parts of the boilers, the angle iron is bent into corre-
sponding sweeps, and for the corners of square boilers
the angle iron is welded together to form the 8 tails
for the respective angles or edges which constitute
the solid corner: this, it hen well done, is no mean
specimen of welding.”2
In our article BRIDGE, Sec. VI. various forms of
rivets are shown—See Figs. 335, 336, and 3417 to
353. Much of the rivetting for the Britannia Tubu—
lar Bridge was done by Mr. Fairbairn’s rivetting
mac/rice.
ROADS and RAILROADS. A road may be de-
fined as an artificial floor so constructed as to present
a straight, level, smooth and hard surface, connecting
difi‘erent parts of a country with each other, and allow-
ing men and animals to travel over it with facility and
despatch. The construction of roads marks the first
change of every nation in emerging from a state of
poverty and barbarism; just as improved means of
intercommunication marks their advance in wealth
and intelligence; for it is found that in proportion as
roads are level and hard are the facilities of moving
over them, and that these facilities greatly diminish
the expenses of travelling and the cost of conveying
goods; and the saving thus effected is applied to
increased production or to other improvements.
The importance of roads was fully admitted by the
nations of antiquity, as appears from the testimony of
their historians. Paved roads are said to have been
first constructed by the Carthaginians ; but the
Romans were the first people to carry out a system of
roads on a most extensive scale, and with such solidity
of construction that many of them remain in use to
the present day. In Italy alone, the ancient Romans
constructed several thousand miles of road, and they
also formed roads in every country of their vast
empire. Although the primary object of these vast
public works was to facilitate the movements of the
military, yet they were productive of great benefit to
the countries through which they passed. The Roman
road-makers connected diiferent stations by means of
straight lines, overcoming natural obstacles with the
skill of a modern railway engineer, making large
excavations, building numerous bridges, and driving
tunnels often of considerable length. And the solidity
of the construction was equal to the boldness of design:
these roads have sustained the traific of 2,000 years
without material injury, thus proving the wisdom of
the method of securing a firm foundation. This was
done where necessary by ramming the ground with
smooth stones, fragments of brick, 820. On this was
constructed a pavement of large stones firmly set in
cement. The stones were occasionally squared, but
were usually of irregular shapes, accurately fitting.
Many kinds of stone were used; but basalt was pre-

(2) Holtzapfi‘el, Mechanical Manipulation, vol. 1. chapter xviii,
where other examples of welded joints are given.
NROATDS ANDFRAILROAD S.
537’
ferred where it could be procured, even when good
materials might be had at less labour and expense. 1f
large blocks of stone could not be had, small stones
of hard quality were cemented together with lime, so
as to form a sort of concrete to the depth of several
feet. Roman roads were generally raised above the
surface of the ground, and they had frequently two
carriage tracks separated by a raised footpath in the
centre.
In Italy the Roman system of road-making has
been partially followed, especially in city pavements.
In Britain the Roman model was not followed, so
that until within quite modern times, the art of road-
making was in a most imperfect condition. The old
roads consisted of paths or trackways, winding about
so as to avoid very hilly or marshy ground, and also
for the purpose of crossing rivers at certain fordable
points. In general, however, a path over a hill was
preferred to one round its base, on account of the
firmer ground afforded by the former. The roads,
such as they were, were supported by parish and
statute labour, which being a voluntary service on the
one hand, and a compulsory one on the other, was
given grudgingly, and was therefore ineffectual. It
was not until the system of maintaining roads by
means of tolls was admitted to be just and practicable,
that reads began to improve. Turnpikes were intro-
duced soon after the Restoration, but they were so
obnoxious to the popular mind that they produced
but little result. In the reign of George II. an act
was passed declaring it to be felony to pull down a
toll-bar: but as the law could not make the public
appreciate the value of toll-b ars, roads continued
almost in their ancient condition as late as 1752-11.‘,
when the traveller seldom saw a turnpike for 200
miles after leaving the vicinity of London. But at
length the general spirit of improvement which re—
sulted from a free government and a free printing-
press had its efiect in improving roads; for in the
let years from 1760 to 17 7 4: not fewer than ass turn-
pike acts were passed, and from that period the
number increased every year, so that long before the
railway system came into operation not less than
23,000 miles of turnpike road had been constructed
in this country.
It would naturally be expected that as roads
multiplied, the principles of their construction would
be investigated. The subject was indeed much dis
cussed, but not until the employment of Telford and
other skilful engineers, on the Highland and Holyhead
roads, was a sound knowledge of the art of road-
making established. Upwards of 900 miles of road
were made or improved under the Highland Road
Commissioners, and in 1815 the Holyhead road im-
provements were commenced under a Government
Commission.1

(1) The work in which Telford’s principles of road~making are
carefully expounded is Sir Henry Parnell’s “ Treatise on Roads,”
26. edition, 1838. We have to express our acknowledgments to
this valuable work in the preparation of this article. Our illus-
trations are mostly from the Folio Atlas of Plates which accom-
panics the “Life of Telford.”

The two great rival road-makers, who for a long
time engaged public attention, each with his own
system, were Telford and M‘Adam. Telford required
that every road should be laid down on a hard, solid,
carefully-prepared foundation. M‘Adam expressly
says: “ I should not care whether the substratum
were soft or hard: 1 should rather prefer a soft one
to a hard one.” Telford saw that the roads of the
United Kingdom were defective; 1, because it was
the custom to mix a large quantity of earth with the
materials which formed the crust of the road; 2, be-
cause this crust was too thin; 3, because it rested on
an elastic substratum. M‘Adam admitted the first
objection, but practically denied it by constructing
his road,on a soft bed : we must, however, assign to
him the merit of being the first to persuade the trus-
tees of turnpikes to set about improving their roads,
by teaching them how to prepare the materials ;
to keep the surface of the road free from ruts by con-
tinually raking and scraping it.
A road destined for much tratlic requires to be laid
out and constructed with greater care, and even on
different principles, than a road on which the traffic
is but small. A road of earth put into a regular form
will answer for a park drive. The same, with a coat-
ing of gravel, will do for light carts and other car-
riages. A road with 10 or 12 inches of broken stones
laid on the natural soil, will answer where the traffic
is not considerable; but very great traffic requires a
road to be as solid and hard as possible, to allow car—
riages to be drawn 011 it with as small an expenditure
of tractive power as possible, an object which all road-
makers ought to have in view.
The enumeration of roads, in the order just indi-
cated, will therefore be as follows :-—-1, a road of earth
put into a regular form; 2, a road of gravel laid on
the natural soil; 3, a road with broken stones laid on
the natural soil; 4:, a road with a foundation of rubble
stones, and a surface of broken stones or gravel; 5,
a road with a foundation of pavement, and a surface
of broken stones; 6, a road, of which the surface is
partly paved, and partly made, with broken stones or
other materials; 7, paved roads; 8, iron railways.
Our attention will be chiefly occupied with the last 3
varieties. And although the general mode of travel-
ling, now in use, is by railroad, it must not be supposed
that the construction of the common road has ceased
to be an object of great importance. There are a
vast number of localities where the common road
aldne can be employed, and the railroad itself depends
for much of its utility and success upon its acces~
sibility by means of common roads.
The designing of a line of road requires much know-
ledge and deliberation. It is always prudent to sur—
vey several different lines, and afterwards decide on
that in which the desirable qualities preponderate.
The surveys should be neatly and accurately protracted
and laid down on good paper, on a scale of 66 yards
to an inch for the ground plan, and of 30 feet to an
inch for the vertical section. The map should be cor-
rectly shaded, so as to exhibit a true representation
of the country. The vertical section should show the
538
ROADS AND RAILROAD S.
nature of the soil and of the different strata as ascer-
tained by boring, in order to be able to determine and
calculate at what inclination the slopes in the cuttings
and embankments will stand. The system recently
adopted of showing upon plans the levels of the ground
by means of contour-lines‘,1 is of great use, not only in
the selection of roads, but in the drainage of towns,
the supply of water, &c. .There should also be noted
down in the plan the existence of gravel-pits, stone-
quarries, 85c. near the line ; and in crossing rivers the
height of the greatest floods should be marked.
These and many other points must be attended to, to
enable the engineer to approach as closely as possible
to the ideal of a road, z'.e. a perfectly straight and
level surface, and perfectly smooth and hard. Of
course he is very far from attaining this perfection in
practice, but it will be found that the best road which
can be had is that which makes the best compromise
of the deviations from perfection. The best road be—
tween two points is that which is the shortest, the
most level, and the cheapest of execution. But this
general rule may admit of qualification, for certain
deviations may be rendered necessary by natural ob-
structions from hills, valleys, and rivers, by the amount
of traffic, the cost of repair, and the necessity for
taking in certain towns or villages in the line of road.
In laying out a road in a hilly country, the spirit-
level must be used in order to show the proper line
of road to be selected. [See LEVELLINe] The ge-
neral rule in surveys is to preserve the straight line,
except when it is necessary to gain the required
rate of inclination without expensive excavations or
embankments. An inclination or gradient‘ of 1 in
35 is found by experience to be just such as will
admit of horses being driven in a stage-coach with
perfect safety when descending as fast as they can
trot. Any rate of inclination greater than this will
very much increase the labour of horses in ascending
hills: and in descending, the horses would have to
restrain the carriage from descending with accelerated
velocity, or a drag would have to be put on the wheel
for the purpose of increasing the friction. The drag,
however, does so much injury to the surface of the
road, that it is in no case desirable to employ it,
unless the safety of the vehicle render it necessary.
With respect to the width of roads, those between
towns of any importance, or where the traffic is con-
siderable, should not be less than 30 feet, besides a
footpath of 6 feet. Even a greater width than this
will be advantageous near large towns and cities.
Moreover, a wide road wears better than a narrow
one, for in the latter case the traffic is more or less
confined to one'track, while in the former it is spread
more equally over the surface. A wide road is also

_
(1) Contour-lines are fine black lines, traversing the surface of
the map in various directions, and where they approach the bor-
ders of the map figures are written against them: each of these
lines indicates that the ground over which it passes is every-
where at a certain ascertained height, as expressed by the side
figures, above some fixed point, termed the datum. These lines,
by their greater or less distance apart, produce the effect of shading,
and exhibit at ' one view the undulations of the surface of a
country.

kept in a drier state than a narrow one, on account‘ of
the superior action of the sun and wind.
With respect to the form of the cross section of the
road, it should not be too much curved, otherwise
carriages will be driven in the centre where they can
stand upright, instead of the sides, where, in very con-
vex reads, it may even be unsafe to travel. It has
been recommended that the cross section of a road
should be formed of two straight lines inclined at the
rate of 1 in 30, ‘and united in the centre or crown of
the road by a segment of a circle, having a radius of
about 90 feet.
The external forces which diminish or destroy the
momentum of carriages in passing over roads, are,
1., collision; 2, friction ; 3, gmoz'ly ; 44, the air.
1. The collision occasioned by hard protuberances and
other inequalities in the surface of the road, tends
greatly to impede motion; it produces resistance to
the wheels, jolts and shocks, wastes the power of
draught, and checks the forward motion of the car-
riage. 2. With respect to friction, if the road be soft
and elastic, the wheels will sink in and the motion of
the carriage be considerably impeded. Gravel roads,
to which an appearance of smoothness is given by
scraping them at great expense, and patching them
with thin layers of very small gravel, are greatly infe-
rior to a road properly constructed with stone mate-
rials. A ‘smooth-looking gravel road is soft in com—
parison with it. It may be laid down as a general
rule, that on every main road where numerous heavy
waggons and stage coaches heavily laden are constantly
travelling, the proper degree of strength which such a
road ought to have, cannot be obtained except by
forming a regular foundation with large stones, set as
a rough pavement, with a coating of at least 6 inches
of broken stone of the hardest kind laid upon it; and
further, that in all cases where the subsoil is elastic,
it is necessary, before the foundation is laid on, that
the elasticity be destroyed, or at least diminished, by
perfect drainage and other contrivances, and by laying
a high embankment of earth upon the elastic soil, so
as to compress it. Although a road, if made with a
thick bed of well-broken hard stones laid upon the
subsoil, may be, to all appearance, a hard and a good
one, still the elasticity of the subsoil will have a con-
siderable effect in adding to the tractive force neces-
sary to draw carriages over it; for the subsoil will
yield more or less under the incumbent weight. It
is therefore only by proper drainage and pressure, and
by making a foundation of large stones in the form of
a regular pavement, that this elasticity can be effec~
tively diminished. That this is the true principle of
road-making, is now admitted by engineers and scien-
tific men. Mr. Law well remarks on this subject,
that “the outer surface of the road should be regarded
merely as a covering to protect the actual working
road beneath, which latter should be sufficiently firm
and substantial to support the whole of the traffic to
which it may be exposed. The real use of the road
materials laid over it should be only to protect this
actual road from being worn and injured by the horses’
feet and the wheels, or from the action of the weather.
ROADS—AN D RAILROADS.
539
And this lower, or sub-road, as it may be called, being
once properly constructed, would last for ever, merely
the outer case or covering requiring to be renewed
from time to time, so as always to preserve asuificient
depth for the protection of the sub-road.” 1
When a proper substratum of earth has been pre-
pared for the bed or formation-surface of a road, a
crust of materials must be so constructed upon it,
that when consolidated it shall be hard enough to pre-
vent the wheels of carriages from sinking or cutting
into it. “ For this purpose,” says Parnell, “it will
not be sufficient merely to lay upon the prepared bed
of earth a coating of broken stones ; for the carriages
passing over them will force those next the earth into
it, and at the same time press much of the earth up-
wards between the stones : this will take place to a
great degree in wet weather, when the bed of earth
will be converted into soft mud by water passing from
the surface of the road through the broken stones
into it. In this way a considerable quantity of earth
will be mixed with the stone materials forming the
crust of the road, and this mixture will make it ex-
tremely imperfect as to hardness, for it cannot in fact
be perfectly hard unless it consists wholly of stones.
It might be possible, in some measure, to cure this
defect by laying on a succession of coatings of broken
stones; but several of these will be necessary, and,
after all, in long-continued wet weather, the mud will
continue to be pressed upwards from the bottom to
the surface of the stones. If even a coating of from
16 to 20 inches of stones be laid on, it will produce
only a palliative of the evil. So that this plan of
making a road will be not only very imperfect, but at
the same time very expensive.”
Mr. Telford’s plan of making a regular bottoming
of rough close-set pavement was adopted with signal
success on the 'Holyhead Road, the Glasgow and
Garlisle Road, 860. It secures the greatest degree of
hardness, and is less expensive than when a thick coat-
ing of broken stones is used, for 6 inches of broken
stones is sufficient when laid on a pavement, and the
pavement may be made of any kind of common stone.
If the bottom stones are laid with their broadest faces
downwards and the interstices filled with stone chips
well driven in, the earthy bed of the road cannot be
pressed up so as to be mixed with the coating of
broken stones. This coating, therefore, when conso-
lidated, will form a solid uniform mass of stone, and
be infinitely harder than one of broken stones when
mixed with the earth of the substratum of the road.
In this way the friction of the wheels on the surface
of the road will be greatly reduced. Indeed it has
been proved by experiment that the force of traction
is in every case in proportion to the strength and
hardness of a road. It was found that on a well
made pavement the power required to draw a Waggon
was 33 lbs. ; on a road made with 6 inches of broken
stone of great hardness laid on a foundation of large
stones set in the form of a pavement, the power

(1) “ Rudiments of the Art of Constructing and Repairing
Common Roads,” Published, 1850, in Weale’s Rudimentary
Series.
required was 46 lbs; on a road made with a thick
coating of broken stone laid on earth, 635 lbs. 5 and on
a road made with a thick coating of gravel laid on
earth, the power required was 1417 lbs.
3. With respect to gravity, it will be evident that,
when a road is not horizontal, the force of gravity is
a great impediment to the draught of the carriage, and
considerably diminishes the efiect which would other-
wise be produced by ahorse in drawing a load. 41. As
regards the resistance of the air, this is very variable,
but as its influence is the same for the same speed
whether the road be good or bad, it need not occupy
much attention. It is only on railways and at high
degrees of speed that its power is felt. It appears
from Smeaton’s experiments that the force of the
wind on a surface of 1 foot square was 1 lb. when
the velocity of the wind was 15 miles an hour; 3 lbs.
when the velocity was 25 miles; 6lbs. at 35 miles,
and 12 lbs. at 50 miles. Supposing the surface of
that part of a carriage acted on by the direct influence
of the wind to be 50 superficial feet, the resistance
which it will meet with from a brisk gale of wind
acting against it will be about 50lbs. when the carriage
is slowly moved; but if the carriage move directly
against the wind with a velocity of 10 miles an hour,
and the wind move with a velocity of 15 miles an
hour, the resistance against the carriage will amount
to 3 lbs. on the square foot, or 150 lbs. on the carriage,
which is equal to the power which 2 horses should
be required to exert when moving with a velocity of
10 miles an hour.
In marking out a line of road, much expense in
cutting and embanking for making the formation-
smface is avoided by a proper selection of high and
low ground. The lowering of heights and the filling
of hollows should be so adjusted as to secure gradual
and continued ascending inclinations to the highest
point. Skill is shown by the road engineer in so
laying out the longitudinal inclinations of a road as to
require the least quantity of cutting and embanking.
For this purpose, he must measure and calculate the
quantity of earth to be removed in cuttings so as to
make it exactly suffice for raising the bellows to the
required heights, a proper allowance being made for
the subsidence of the soil. In making a deep cutting
through a hill the slopes of the banks should not be
less than 2 feet horizontal to 1 foot perpendicular,
except in passing through stone: for although several
kinds of earth will stand at steeper inclinations, a
slope of 2 to I is necessary in order to admit the
sun and the wind to the road. The green sod and
fertile soil on the surface of the land cut through is
to be preserved in order to be laid on the slopes as
soon as they are formed. If sod is not to be had, the
slopes must be covered with 3 or 4 inches of the
surface mould, and hay seeds sewn on it; by which
process’ the slopes will soon be covered with grass,
which will assist in preventing them from slipping. If
stone is to be had, the slopes should be supported by a
wall raised 2 or 3 feet high at the bottom: such walls
prevent the earth from falling from the slopes into
the side channels, and improve the appearance of the
54:0
ROADS AND RAILROADS.
road. If an additional quantity of earth be wanted
for an embankment, the slopes through the cuttings
on the south side may be made of an inclination of 8
to 1: this will allow the sun and the wind to play
more freely on the road. In rocky and rugged
countries the inclination may be obtained by building
retaining walls and filling between them with earth.
In forming a road along the face of a precipice awall
must be built to support it. An inclination in the
face of the precipice of g}; foot perpendicular to 1
foot horizontal will admit of a retaining wall being
built. By building such a wall, say 80 feet high, and
cutting 10 feet at that height into the rock and filling
(up the space within the wall, a road of sufieient
breadth will be obtained. See Fig. 1831. In form-
ing the bed of a
road it should if
possible be ele-
vated by means
of earth at least
2 feet above the
natural surface
of the adjoining
ground, so as
to prevent water
from running un-
der er soaking
into it therefrom.
This plan may
not always be
possible, for the
surface must
sometimes be cut
into in order to
get the proper
longitudinal in—
elinations; but it is always desirable to get these
inclinations by embanking rather than cutting, for

Fig. 1831. RETAINING wane.


there is always a better exposure of the surface on
embankments, and a risk in all cuttings of the slopes
falling down. One of the greatest defects of old
roads is their being sunk below the adjacent fields.
Great care is required in forming embankments.
The base must be formed at first of its full breadth,
and the earth be laid on in regular layers or courses
not exceeding 4! feet in thickness. In forming high
embankments the earth should be laid on in concave
courses: for if laid on in cancer it is most likely to
slip. In forming embankments along the sides of
hills, siclcformz'lzy, as it is called, the slope should be
cut into level steps to receive the earth, which should
be well compressed, and land-springs intercepted by
proper drainage. For this purpose a drain should
be cut on the upper side of the road, and open drains
be made on the side of the hill above the road, to
catch the surface water.
The slopes at which cuttings and embankments can
be made with safety depend on the nature of the soil.
In the London and plastic clay formations the slopes
of embankments or cuttings, if more than 4: feet high,
should not have a steeper slope than 8 feet horizontal
for 1 foot perpendicular. In cuttings in chalk or chalk
marl the slopes will stand at 1 to 1. In sandstone,
if it be solid, hard, and uniform, the slopes will stand
at :1— to 1, or nearly perpendicular.
In making a road there must be provision for
drainage, not only of the upper surface, but also of
the formation surface. If the transverse section be
gently convex, or of the form already indicated, the
surface drainage will be assisted 5 but in addition to
this, a ditch should be formed on each side of the
road, of sufficient capacity to receive and carry off
all the water that may fall on the road. Between
the footpath and the road a channel_ or water course
should be formed, and under the footpath, at dis-
tances of about 60 feet, drains of tiles or pipes should
1’ A

P
E


\ i“ 1”‘ If
\\ as \\\\\\\\§§W§\\W
Fig. 1832. cnoss sno'rron or A NEW ROAD WITH A raven FOUNDATION.
B s, pavement, above which is a layer of broken stones.
s, green sod.
P P, posts. 9, gravel footpath.
be formed for conveying the water into the ditch.
The small drains should not have too great a fall, or
they will produce through them so rapid a current







may; = “ Rare ,. 3%,; ‘ "'” " - .: vl-Iiyz’ Pg}; ' ‘ ‘E, "x‘
I.“ ._ -.' ' J-li‘
,, ‘film..- is \
..~\ >3. ,0.’
that the ground about them will be washed away
or undermined. If the surface be properly drained
very little water will find its way to the substratum,
sari-gs‘ i I
J v_ x
is ‘





‘E
'm I‘i' \ . 1':
v A \ ' "5|
’:\ VJ / ‘MM _‘ 5|
5 ' 1 x 1 9'» 51.0 6 Jae‘ ' ' 5": ~ (i \‘Z ‘g: \‘Q‘ ' v o‘gri‘.“ \13‘’ € 0' Y o‘ ‘ " 71°51?“ ‘xvi’: ‘a v v r‘J' "um: ' 1) “
, \ ~ - \ . .-
s a” \ ...\
\


S
~\\ “"— \n‘:
\\\ Xian“ \
l\\\ xvi.“ \
\ \\h\\.\\\\\\\\\ \
as
(Telfor d.)
N 8, natural surface.
D 1), main drains. d d, pipe drains.
except the latter be a strong clay, or of a wet peaty
nature. In such case, a system of under-drainage
must be resorted to, and trenches or drains be formed
across the road at distances of 20 or 30 or more feet,
according to circumstances. Each trench should
contain a drain at least 4 inches square internally,
made of old bricks, tiles, or flat stones, and the re-
mainder of the trench should be filled up with coarse
stones washed free from clay and dirt, as shown in
Fig. 1833.
In places where stone is scarce, but gravel and
lime abundant, concrete may be used for the‘ solid
foundation of a road with good effect. In laying it
down it may be spread to the depth of 6 inches over
the half breadth of the road; and upon this 6 inches
~ ROADS AND RAILROADS.
541
ref good hard gravel or broken stone in 2 courses 3
inches at a time: the first course may be laid on 3-
lfew hours after the concrete has. been SPl‘ead- NO
‘ltraffic must be allowed until the concrete has become
lhard and solid. The use of concrete allows a good
solid road to be formed with round pebbly gravel
:and other materials not otherwise well adapted to
iroad~making.1 The gravel should be free-from clay
:and dirt, and consist of stones and sand, the latter
in suificient quantity to fill up the interstices of the
iformer. About 5 or 6 parts of such gravel are to be
mixed with 1 part of ground unslacked lime, sufficient
wvater being added to slack the lime: it is then to
lbe thoroughly mixed up, immediately thrown into its
place and trimmed to the proper form: the first layer
[of broken stones or screened gravel is then to be
put 011 just when the concrete is about to set.
When the broken stones which cover a road are
in angular masses they quickly wedge together into
:a smooth hard surface; but if the stones are round
and pebbly, as most gravel stones are, they must be
(mixed with some binding material to fill up the inter-
:stices and prevent them from rolling about. With-
out this binding material such a road would not
become solid; but its use leads to much in'con-
venience in wet weather, and especially in a thaw after
:;a frost; the expansion of the water in freezing breaks
.up the road, and the subsequent thaw reduces every-
thing to a loose spongy state. ~
The method of forming a road ‘entirely of angular
pieces of stone without any kind of binding material
was adopted with great success by McAdam, whose
name is perpetuated in the verb to macadamz'ze. The
stones used for the purpose must be hard and tough,
such as the whinstones, basalts, granites, and beach
pebbles, so that'they may resist the action of the
wheels. Hardness alone is not sufiicient, for flint
stones are hard, but brittle, and are soon crushed to
powder, as are also, for a contrary reason, the softer
sandstones : the harder and more compact limestones
may be used, but all the limestones are retentive of
water, and in frosty weather become disintegrated.
The angular fragments must be of such a size as to
pass freely by their largest dimensions through a
ring 2.}, inches in diameter. _
In situations where gravel is the only road material
its bad properties may to a certain extent be removed
by judicious treatment. When taken from the pit
it should be passed over a screen that will allow all
stones less than :2- inch to pass " through it, and the
fine stuff or lzoygz'zz should be kept for forming foot—
paths, and of the remainder the large stones should
be broken to the size of the gage-ring, and kept for
the upper layer. The loam which accompanies the
gravel serves as the binding material, and should not
be separated; but the screened gravel should be

(1) The employment of concrete of gravel and lime for roads
was first proposed by Mr. Thomas Hughes, who has given
instructions for'its application in his work on “The Practice
of Making and Repairing Roads,” 1838.——See also Mr. C. Penfold's
“ Practical Treatise of the best Mode of Making and Repairing
Roads.” ~
spread over the whole road to the depth of 6 inches.
The road may then be opened for traffic, and in this,
as in other cases of new roads, men should be kept
constantly employed upon it to .keep every rut raked
in as soon as it appears. Guards or fenders should
also be so placed on the road as to make the carriages
pass over every part of its surface in turn. Unless
these precautions be observed the road will never
become firm. When ruts are formed they mark out
a kind of track which carriages follow, and thus the
ruts are being continually widened and increased: in
wet weather they become filled with water, which,
not being able to escape, softens the materials, which
are still further disintegrated by every vehicle. Thus
the road becomes broken up and unsafe, and a much
larger expenditure is required for its repair than for
the permanent maintenance of a body of labourers
upon it.
In chalk districts, this substance may be used for
the foundation of the road, provided it can be placed
at such a depth as to be beyond the influence of frost.
If this cannot be done, the chalk may be used as
a binding material with gravel on the surface, but it
must be first reduced to powder and be well mixed
with the gravel before laying it down.
In passing over soft and boggy ground, the founda-
tion of roads should be laid with bushes or bundles
of faggots at such a depth as to ensure their being
always kept in a damp state; for if they ‘become
alternately wet and dry, they soon rot, and thus form
a soft substratum to the road.
In improving old roads, it will often be found
necessary to straighten their course by cutting ofi
corners and bends; or to improve their levels by
avoiding or lowering hills and embanking valleys;
to increase their width and render it uniform through-
out. .The transverse section of the road must also
be corrected, ruts filled up, and the side ditches
cleansed and deepened: trees or hedges too near
the road should be cut down, and mud banks re-
moved. In" improving a road it is not imusual for
the surveyor to be satisfied with merely heaping
on fresh materials; whereas, as Mr. M°Adam re-
marks, “ generally the roads of the kingdom contain
a supply of material sufficient for their use for several
years, if they were properly lifted and applied.” In
correcting the transverse form of the road, the parts
which are too high must be cut down and the de-
pressed parts raised, either by the proper arrange-
ment of old materials or the addition of new. If
these materials be not too rotten, too brittle, or too
thin, the operation of Zg'fl‘irzg may he adopted. This
consists in loosening and turning the surface of the
road to the depth of about 4.‘ inches, taking up large
stones for the purpose of breaking them to the proper
size, and removing other materials which are not in
a fit state. If the materials are of such a nature that
they would crumble on being lifted, then the sur-
face of the road must be carefully cleaned from mud
and dirt, and fresh materials be laid on in a coat not
i exceeding 2 or 3 inches in thickness. If the surface
, of the road is hard, but thin, all that may be neces-

5412 ROADS AND
RAILROADS.
sary will be to loosen it with a pick in order that the
new material may quickly combine with the old.
As in wet weather the roads should be constantly
scraped clean, so in dry weather they should be re—
gularly watered. A long continuance of dry weather
renders the road materials very brittle; they are
ground to powder by the trafiic, and the dust is
wafted away by the winds. This may be prevented
F "
by regular watering; but the water-cart must not
pour a deluge on the road, but should be so con-
trived as to produce the effect of a gentle shower of
ram.
When fences are used they should be as low as
possible, and placed as far from the sides of the road
as possible, in order not to intercept the sun and
the wind.







/
l m, _ ill/Fr '1
mid/f”, ‘V 11 "/ ////////,,, ‘WI-£6 >~ ,//"/’//,~ w , "WH/Ifr."
.wflr/‘d/ifl/a . a ' / l/r/z/f-t- " .- ,. a J . . , "I /"//’ WW - r "r- 1' ’” ‘r , . . '1 I
97/ ’/ WFWIF'FI/‘l/V v‘ /’,/l'/;i..h m ,f7f////////‘//I%7/§H , I ,1 I/ I,” '
-/ II.’ I // a, ’/, l /l,. , ' MI” /-./ ,/ 'j" lam/1.7417’ W.- 7,717.“ 7,574,371.. ,a- .141 ;d/l'v fi/ /" I. J. . , / /, . I‘ I ,l ' a 1 || ‘
’ ' ' "/12; / H’ ’/ ’” ’-////./'.- ./ ////./ ,/ // If’ " "’ ' ' ' '
Fig.1834. cnoss snc'rron OF AN UNIMPROVED OLD ROAD.
w w, waste ground. F, footpath.
T,
. at;
“1": tr‘,
. 1;


.


_\;-~_-\-.
' \ \
“X ~ . .M'z'.
. \ *' \ \\ --
~
a“ \ .\ \\\\\\\\\ \.. .. , ‘\ \ \\\~‘
\\ \\ \\\\\ \\ H .
Fig. 1835. CROSS SECTION OF THE SAME
F, footpath. s s, green sod.
The tools used in road-making are represented in
the following figures. In working in clay, as in cut-
ting deep drains, &c., a narrow
spade, Fig. 1836, considerably
curved in the blade, called a
gmflz'rzg/ tool, is used. The best
kind of sizovel for road work,
Fig. 1837, is pointed in the
blade, and has a curved handle,
to allow the workman to bring
the blade flat to the ground
without stooping. When metal
rails can be laid down, the
true]: or small wag/on, Fig. 1838,
is the best description of car-
F’g-1836- riage for removing earth. It
holds a cubic yard of earth. The body is of elm, the
frame of oak, and the wheels and axles are of iron. Two

r


Fig. 1838.
kinds of lzammers, Figs. 1839, 1840, are used in road
works. The handles should be flexible, made of straight
grained ash, particularly those for breaking pebbles.
The small hammers should have a chisel face, and
the larger ones a convex face, about —§— inch in
diameter.‘ Those made of cast-steel wear better than
wrought-iron, and seldom break at the eye. Prorzyed




\ I 4 ‘I’: >‘-\.__
Is I u u _\-. "‘-._‘\~“\\\;~\‘~>.~.
~~~~ ~ ~ \‘F‘i ‘-E:¢<\“"\ Rnhhf ‘\“W
~ .
r, 414,3;
‘- Q!‘ .\
‘ “an
ROAD WHEN IMPROVED.
d, pipe drain.




1
f
4
/
1
\\\ \
shovels, Fig. 184], are useful for filling stones, when
broken, into carts or barrows. A man can lift stones


Fig. 1839.
more easily and quickly with one of these shovels
than with a common one, and does not take up any
earth with them. Scrapers are sometimes made of
wood shod with iron, but
those of plate iron are to
be preferred: they should be 6 inches deep, and
from 14: to 18 inches long
in the blade, according to the materials of which
the road is composed; the softer and more fluid


Fiy: 1840.


Fig. 1841.
the mud, the larger the scrapers should be. They
should be turned alittle round at the ends to pre-
vent the mud from escaping. The best scrapers are
made of old saw-plates, stiffened on the back by a rib
of wrought-iron, or by rivetting the plate to a board
of elm cut to the proper width and length, and about
half an inch thick. The pateizt road-scraper consists
of a series or row of scrapers placed in a frame, and
mounted on wheels: it is worked crosswise on the

ROADS AND RAILROADS.
5 43
road, and deposits the dirt or dust on the side. It is
easily worked by one man, and cleans above a mile of
road per day, or about 5 times as much as can be
done with the common scraper, and the work is better
performed. The advantages of frequently scraping
roads are, 1, the improvement of the surface, which
cannot otherwise be kept hard and firm ; 2, the faci-
lity afforded to fast travelling by removing a great
obstruction to the progress of carriages; 3, the pre-
servation of roads by removing the dirt, which absorbs
and retains water on the surface; 4L, assistance to
the surveyor, by enabling him to take advantage of
favourable periods of weather for cleaning his roads;
5, the saving of money, which may be applied to the
strengthening and improving the roads. Mr. Whit-
worth of Manchester has contrived a machine for
sweeping up the mud and carrying it away at once.
It consists of a kind of endless broom passing round
rollers attached to a mud-cart, and so connected by
cog-wheels with the wheels of the cart, that when
the cart is drawn forwards the broom revolves and

Fig. 1842.
sweeps the mud from the surface of the read up an
inclined plane into the cart. Fig. 184% is a lzerlgz'rzg
kmfe, or plus/ling tool, for trimming hedges, and if
properly used, does the work as effectually as a pair
of shears, and more quickly. It should be made suf-
ficiently light to be used with one hand and be pro-
perly balanced on the
handle, so that the man i‘
may wield it with proper '
effect. Working levels
[Z " \ ----- -~
_ an" nun'lhmftlllllllllllllfl l ""
Fig. 1843.
are required in laying out new works, and in repair-
ing old roads. M P, Fig.1843, is a useful kind of
level : on the horizontal bar are placed 4.- gages, a b 0 cl,
made to move perpendicularly to the line n r in dove-
tailed grooves cut in the horizontal bar. When any
one of these is adjusted to project a proper depth below
the line, it may be fixed by a thumb-screw, which will
retain the gage (shown separately in Fig. 1844:) in the
desired position. By means of this level the true
transverse section of the road is formed. The plum-
met in the centre of the level shows when the straight-
edge is horizontal. A line is drawn near the end of
the bar at M, which marks the middle of the road;
and at the distance of 41 feet from this point, the
gage a is fixed in the groove by means of the thumb-
screw, to the depth below the straight-edge required
by the curvature of the road. The gages 6 e (Z are,
in like manner, fixed, until their lower ends coincide
with the surface which is to be given to a road 30






feet in width; and in order to ascertain whether the
surface of any road is constructed to the required
inclination and form, all that is necessarygis to apply
the level, which, having been made horizontal by
means of the plummet, should rest upon the road at
the lower extremity of each of the gages a 6 0 cl.
Levels for laying out slopes are made of a bar
2 long: on the centre, near the middle of the
rod, a triangular piece of wood of the same
thickness is nailed; the sides of this triangu-
lar piece are so formed, that when the rod
is placed upon a slope of 1 to 2 or I to 8, a
small pocket level, placed on one ' "‘
side of the triangle, will be horizon-
tal, and the bubble will remain in the
centre. Fig. 1845 is a ring-gage,
for ascertaining the size of broken
Fig.1844, stones. Fig. 1845.
PAVED Hours. In constructing roads through
towns, where the traffic is considerable, it is desirable
that the surface be
paved. In such cases
macadamized roads are
dusty in dry weather,
and muddy in wet: they produce less noise from
carriages passing over them than paved roads; but
if the latter are properly laid, the difference in respect
of noise is inconsiderable.
In forming roads through streets it is even more
important than in country roads to secure a good
foundation. In fact, the foundation ought to be
regarded as the real road, and the pavement as a
contrivance for preserving it from destruction.
The foundation may be formed of concrete or
of broken stone; and in
cases where it is practi-
& cable the old road may
i‘; itself form the founda-
tion ; for which purpose
the stones are to be
taken up and carefully
laid down to the proper cross section, and upon this
the stone pavement is to be formed. Where the
foundation is formed of broken stone it should be as
carefully laid out as for a macadamized road, and in
that state it should be opened for traffic, and when
properly consolidated the pavement should he laid on,
the stones being bedded in some coarse kind of
mortar.
When concrete is used for the foundation, the loose
ground at the surface should first be removed to a
depth depending on the nature of the ground, but
generally to such a depth as to allow at least from 12
to 18 inches of concrete beneath the pavement. The
stones should be well bedded upon the concrete in a
kind of coarse mortar, which should also be filled in
between the joints.
The best kind of stone for paving is granite : that
from Guernsey and Aberdeen is the best, inasmuch as
it does not assume a polished surface by wear, which




544i ROADS AND
RAILROAD S.
is a defect of most hard stones. If limestone and
freestone are used, the hardest varieties only should
be selected. The best form for the stones is that
of rectangular blocks, from 8 to 15 inches in depth,
depending on the traffic, about 18 inches in length,
and 3 or 41 inches wide. Experience has abundantly
shown that narrow stones are preferable to wide ones.
The stones must be sorted according to their depths
and widths, for if of unequal depth they will form
hollows on the surface, and if of unequal width they
Will not run across the road in parallel courses. The
courses should break joint as in masonry or brick-
VVOl‘k, and‘there should also be a good firm curb on
each side of the road for the courses to abut against.
In laying‘ the stones, the courses should be begun on
each side, and worked towards the centre; the joints
between the stones should be thin, and the last stone
should fit tightly, so as to form a key to the whole.
The stones should then be well rammed down with a
heavy punner, and any stone which falls below the
general surface must be taken up and packed beneath.
it is not usual to bed the stones in mortar in the
‘:manner recommended, but to pour over the surface
a. thin grouting of sand and lime after the pavement
has been laid. This is a very poor and imperfect sub-
stitute for the plan with mortar, which, if properly
carried out on a firm‘ foundation, would produce a
‘road almost indestructible.
Paved roads after they are opened for traific should
be constantly watched, and any stones which sink
down should be taken up, and concrete put beneath
them so as to raise them a little above the general
level. The usual plan, in London at least, is to leave
the road to its fate, and when it has become too bad
to be used, it is taken up and relaid. The disturbance
of the road for the repair of sewers or for laying down
gas and water pipes is an evil which ought to be
diminished as far as possible, and when the necessary
‘Work is done the road should be carefully restored to
its'former condition.
Where the inclination is considerable the pavement
should be, so laid that horses ascending with heavy
loads may have a more perfect hold for their feet.
For ‘this purpose two methods have been adopted.
That shown in Fig. 18416‘ is, to lay between the rows
of paving stones 'a course of ‘slate rather less than an
inch in thickness, and about an inch less in depth than
the stones. In this way a series of channels or
‘ r
’ i \


._\
Fig. 1846.


grooves about an inch in width and depth is formed,
which affords sufficient hold for the horses’ feet. The
other method, Fig. 181W, is, to lay the stones in a
somewhat canted or sloped position, so as to form a
series of ledges or steps which evidently assist a horse
in ascen ' 0' a hill with a load.
A few years ago wood pavements were introduced
into London with a degree of zeal which, if it had
only been tempered with judgment and discretion,

might have ensured the permanent comfort of almost
noiseless roads. Wooden pavements are declared to
have failed, but no earnest attempt appears to have
been made to ascertain the cause of failure with a
view to its removal; the system was rapidly and
extensively adopted, and hastily abandoned. Now
the very same cause which leads to the expenditure
of such large sums of money in the repair of roads
led to the failure of wooden pavements, viz. the want
of a solid foundation ; and this want was sooner felt
in the case of wood than in that of granite, on account
of the less weight and inertia of the wood. In
certain states of the weather the wooden surface was
found to be slippery, but this might have been
remedied; but there was no remedy for the numerous
pits and cavities formed on the surface, except that
which is required for all roads, viz. a firm and solid
foundation. .
The method of constructing asphaltum roads is
described under ASI’HALTUM.
RAILWAY, or Rxrnnonn, is a road in which rails of
iron are laid down upon a smooth solid foundation
for the purpose of facilitating the motion of wheel
carriages. The power by which such carriages are
moved does not afi’ect the definition; they may be’
drawn by horses, or by locomotive steam-engines;
they may descend inclines by their own gravity, or be
drawn along levels and up inclines by means of sta-
tionary engines 5 the principles upon which railways
are constructed will in all cases be nearly alike.
Nearly two centuries before the introduction of the
locomotive steam-engine, the collieries of the north of
England made use of wooden rails, tram or waggon
ways, for the purpose of reducing the labour of draw-
ing coals from the pit’s mouth to the place of shipment.
They consisted at first simply of pieces of wood
imbedded in the ordinary road in such a way as to
form tolerably smooth tracks for the wheels of the
carts or waggons. It was found that by this contriv-
ance the horses could perform a much larger quantity
of work, or, still better, fewer horses were required for
the same amount of work, thereby diminishing the
number of servants, &c. These wooden railways do
not appear to have been known out of the collieries,




-~=a
aw"
. Y
\ \v‘: .5’ \
. _ _ \ .
r t ‘i f'mFkvb-N‘vi. 'RiEi's-f ‘ x5955" ~ . ‘4" “sew-“rs. *fi' - YiSWm-a .3. , gigs,‘ g 31$}, max“ \\_‘_V_\I §R§.;($‘~ §~:\\-‘-\~\Fi\\vfi: Qt“:
Fig. 1849.
but we learn something of their construction from the
following description made about the year 17 65 :—--
The road was first levelled and reduced to as uniform
an inclination as was generally practicable: roughly
squared pieces of wood called sleepers s .9, Figs. 18et8,
ROADS AND RAILROAD S.
545
1811i), about '6 feet long and A to 8 inches square, were
then laid across it at a distance of about 2 or 3 feet
from each other, and upon these other pieces, r r,
carefully sawn, about 6 or 7 inches wide and 5 deep,
were fastened by pegs so as to form two wheel tracks
about 4! feet apart. The spaces between the sleepers
and under the rails were lastly filled up with ashes,
gravel, or other road materials.
In this arrangement the removal of a broken or
worn-out rail injured the sleepers in consequence
of the peg—holes becoming too large. But by spiking
or pegging down a second set of rails ,r’, Fig. 1850,



upon the first 7', the upper rails could be frequently re-
newed without disturbing the sleepers 8. By thus rais-
ing the road a larger quantity of road material could
be spread over the sleepers, whereby they were the
better protected from wear. The waggons used on
these wooden railways contained each about 2 or 3 tons
of coal, and were mounted upon small wheels, furnished
' I w o 0 o a
with a flange or projecting run, which came 1n con-
tact with the side of the rail and kept the Waggon
in its place. Such waggons were drawn by one horse.
When the draught was harder than usual in conse-
quence of a steep ascent or a sharp curve in the line,
friction was diminished by nailing to the wooden rail
thin plates of malleable iron. These lines were com—
monly constructed with a descent towards the river
or seashore, and to prevent the descent from being
too abrupt, it was usual to form an elevated staid/z at
the river end of the line, and to shoot the coals from
the waggons by an inclined plane into the holds of the
ships. So also in cases where the incline would prove
to be too steep if distributed equally over the line,
the greater portion of the descent was made to in-
cline gradually, andthe rest of the fall was accom-
plished by one or more inclined planes of great
steepness called rams, down which the waggons de-
scended by their own gravity, the velocity being
checked by a piece of wood called a bra/re or convoy
pressed forcibly upon one or both of the wheels
on one side of the Waggon. This kind of railway
continued in use for about 150 years without altera-
tion, except a few attempts to introduce stone in-
stead of wood: but it was found that what the stone-
ways gained in durability, they lost in smoothness.
A great advance towards our present system was the
introduction of cast-iron plates upon wooden rails, and
it is a curious fact that this improvement was the
result of accident rather than design. About the
year 1767, when the price of iron was very low, it
occurred to the proprietors of the ‘Colebrook _Dale
iron works, as a means of keeping their furnaces at
work, to cast bars in such a form as to admit of their
being laid down upon a wooden railway in use at the
works: this, it was thought, would save the expense
of repairing the railway, but that if a sudden rise
' should take place in the price of iron, the rails could
VOL. 11.

be taken up and sold as pigs. These bars or scant,-
Zz'ngs were 5 feet long, 41 inches broad, and 1;} inch
thick, and they were cast with 3 holes for the con-
venience of nailing to the wooden rails. The road was
said to be successful, and it was pointed out as an
advantage (which we should now consider to be
a great misfortune) that vehicles could be turned ofl
the track with great ease in consequence of the ab-
sence of a guiding flange. Attention was now called
to this kind of road, and many attempts were made
to combine the smoothness of a railway with the
character of a common road. One of the best of
these contrivances was that patented in 1803 by Mr.
Woodhouse, who proposed to make rails of the form
shown in section, Fig. 1851, to be imbedded in an
ordinary pavement or road. The concave surface of
the upper part of the rail was intended to keep car-
riages in the right direction, and yet allow of their
being easily turned out of the road. Some of the
iron gutters in the streets
of London are made of this _
form, and the relief to the p w
draught which they afl'ord 3‘
is known to every carman. 17718521
About the year 1776 the Colebrook Dale rail was im-
proved by the addition of an upright flange, Fig. 1852,
for the purpose of preventing carriages from running
off the line. Bails of this form were first fixed upon
cross sleepers of wood, as in Fig. 1853, for which pur-
pose they were cast with holes for nails; and they were
laid down with the flanges turned inwards, as shown
in Fig. 1853, which is an end section of the two rails


Fig. 1851.
. llllllllv


J”! \fis-au. .
.
"25.‘
1 l
, .


__d"
_ ,--~-‘,_-
————--J—.-

. "___-—

. ' l a
_..A' v" l - .
QEF ‘ ‘1} f
é
5:; -‘ :
mm$seefii§5 \ \ . \ ‘i\§usm\\\<%$\
___

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'-___-'

~_~-_-——v=¢_—_”__
' ":8- ~.... _;___'_\_
“ WMQQ .
Fig. 1853.
fixed to a sleeper with a pair of wheels on them.
About the year 1793 blocks of stone were used instead




§~ . I
a l , T if r
—— it?‘ ‘5'!
' 6 ta
8 5 L1
’ Fig. 1854.


of the wooden sleepers. Each block .9, Fig. 1854, was
about a foot square, and 8 or 9 inches deep; it was
imbedded in the road under the junction or joint of
every two rails, which were spiked down to wooden
plugs a driven into holes in the stone. In this figure
7' is the rail, 5 the fish-belly, and f the flange. The
increased durability of this plan over wooden sleepers
was soon appreciated. This kind of railway, called
the plate railway or z’rmzzroad,1 is still used in min-
ing districts for the carriage of coal, iron-stone,

(1) From Mr. Outram, a gentleman extensively connected with
the collieries. These roads were first called outram roads.
INN
54-6
‘ROADS AND RAILROADS.
&c.: it is easily constructed, and the vehicles used
upon it can also be run upon common roads. The
form of the rail is, however, objectionable, and it
allows stones and dirt to accumulate upon it, which
not only impede the traffic, but tend to throw the
carriage off the line. The defects of the plate-rails
were remedied by the introduction of edge-rails,
which were first extensively used in 1801, for the
conveyance of slate from the quarries of Lord Pen-
rhyn. They were of an oval section, Fig. 1855, the
larger diameter being vertical. The length was 41-3,-
feet, and beneath each end was cast a dove-tailed
block, which fitted into an iron sill imbedded in the
road. The wheels had a grooved tire, fitting loosely
on the rail ; but it was found
that the groove became so
deepened by wear as to fit the
rail tightly, and thus occasion
' much friction. An attempt
Fig' 1855' to remedy this was by making
the bearing surface of the rail and the corresponding
part of the wheel flat, as shown in Fig. 1856. In
spite of many defects, such was the saving of power
on this line that 10 horses were found suflicient for
work which formerly required ‘£00 on a common road.
A few years after the construction of this line, edge-
rails were adopted by the coal owners of the north,
and a better form of rail was contrived, viz. the fish-
'belZz'ecl mil, Fig. 1857', the lower edge being curved
s" \
\\ %
Fig. 1856.




llllllllllllllllllllmlllllllflllllllllllllll








Ulllmltfltlllw Wm“! (WM . .luunuimnuwluumululn'luur f a? .lhaillgl tantrumnypmpnnaa o
Fig. 1857.
so as to give the rail greater depth in the centre than
at the ends or points of support: 5 is the cross sec-
tion of the rail at c, and a the cross section at the
end. The rails were cast in lengths of 3 or 4 feet,
and the ends so contrived as to form a half-lap joint,
Fig. 1858 fitting into a cavity
' a cast-iron chair a, spiked
down to the stone or wooden
F59. 1858. sleeper, Figs. 1857, 1858, which
show a side view and plan of the chair,
&c. Fig. 1859 is a cross section of the
rail and chair, with a portion of the
tire of the wheel upon the rail. The
\\ .v i ‘ flange used in the plate railway for keep-
Fiy.1859- ing the carriage on the rail is in this
example, Fig. 1859, transferred to the wheel, and this
flange may be made smaller on the wheel than on the
rail; and to prevent the flange from coming in con—
tact with the rails more than is absolutely necessary,
the wheel tire is made slightly conical. Fish-bellied
rails have been superseded by parallel rails, or those
which have an equal depth from end to end.
A further improvement in rails was made by the
introduction of malleable instead of cast-iron. Rails
of cast-iron, especially those of the tram-plate form,
were, from the brittleness of the metal, very liable to
fracture, even when the carriages moved over them


>
at a low rate of speed; and the attempts to remedy
this evil by casting the rails of greater thickness,
were not very successful. Rails of malleable iron, of
the square or flat form, were laid down as early as
1808, this being the only form which the machinery
of that time could produce economically. Attempts
were made to form a cheap and durable rail by the
combination of wrought and cast iron; but no plan
was successful until the method was introduced in
1820 of rolling iron into any required shape. [See
IRON, Fig. 12410.] The tough fibrous texture of
wrought-iron makes it not liable to break from the
blows and concussions of the carriages, while the form
which is given to the rail prevents it from bending.
It also allows of railsbeing made 15 feet long, whereby
the number of joints is diminished‘; whereas with cast-
iron rails the space between the points of support
was not more than 3 or 4: feet, owing to the unavoid-
able shortness of the rail.
The waggons used on the cast-iron rails were made
of small size in order to distribute the load over a
considerable length of the line, and thus diminish the
risk of fracture. Each waggon moved on 41. wheels,
and being guided by the flanges on a straight road,
the axles of the waggons were not attached, as in other ‘
vehicles, so as to allow them to turn by the wheels
locking under the body ; nor was it advisable to make
the wheels revolve on the axles, but to fix them
firmly thereto, .and make the axle revolve in bearings
attached to the body of the carriage. Iron wheels
were used: where thetraflic was slow, cast metal was
employed; and for high speed, the most important
parts were of malleable iron. Wrought-iron edge-
rails were found to wear out cast-iron wheels very:
rapidly, and this led to the plan of case-hardening
them. The carriages were further improved by being
mounted on springs.
With respect to the power employed for moving
the carriages on railroads, the locomotive steam—
engine was slow in making its appearance. Animal
power was used in transporting mineral produce to
the place of shipment; and as the loaded waggons
generally had to descend to the river or to the sea-
shore, gravity was also made use of, and in some
cases superseded animal power. Where the incline
was very steep, animal power could not be used. In
such cases a self-acting inclined plane was employed,
011 which a train of loaded carriages was allowed to
descend by the force of gravity: to this train was
attached a rope which, after passing round a wheel
at the top of the incline, proceeded down the slope,
and was fastened to a train of empty waggons, so that
the force of the descent of the loaded train was suf-
ficient to cause the empty train to ascend to the top
of the incline. This excellent arrangement still con-
tinues in use. In other cases, where the ascent was
too great for horses, the carriages have been drawn
up by the power of stationary steam-engines by means
of ropes guided by pulleys in the centre of the track.
With respect to the locomotive or moveable ‘steam-
engine, a suggestion for such an engine occurs in one
of the patents of Watt as early as 1784, but such an. '
ROADS AND RAILROAD S;
.5417
engine does not appear to have been constructed until
1802, when Messrs. Trevithick and Vivian took out‘
a patent for a high-pressure engine, which in 1805
was worked on a tramway at Merthyr Tydvil. This
engine, although simple in its structure, possessed all
the essential arrangements of modern engines. Trevi-
thick found, that the adhesion between the wheels of
the engine and the rails was sufficient for progressive
motion on a level or nearly level line, yet he feared
that, on too steep an incline, or with too heavy a
load, the wheels would slip round on the rails without
advancing, and he proposed to remedy this by making
the driving-wheels uneven by means of projecting
bolt-heads, cross grooves, or fittings to the rails. This
idea prevailed for many years, and engineers, instead
of trying the experiment, exerted their inventive
powers to remedy the imaginary evil. In 1811, Mr.
Blenkinsop patented a locomotive engine in which the
driving-wheel was furnished with cogs, which entered
a rack laid down by the side of the ordinary rails.
This plan was put in action on a colliery line near
Leeds, but the friction was found to be so great that
the plan was abandoned. In 1818, Messrs. Chapman
constructed engines on 8 wheels, all of which were
,driven by the power in order to increase the adhe-
sion. About this time Mr. Brunton constructed a
locomotive machine, which was made to advance by
the alternate motion of 2 levers thrust out from the
back of the engine. Similar propellers were used by
Gordon and Gurney on common roads. In 181% and
1815 engines with plain wheels were again tried, and
being found efficient, were used upon some of the
northern railways. In 1816 and 1817 patents were
taken out by Messrs. George Stevenson, Dodd, and
Losh, for locomotives, which were used upon colliery
railways near Newcastle-upon-Tyne. It was not, how-
ever, until the Liverpool and Manchester railway
approached completion, ‘that any serious attempts
were made to apply the locomotive to the purpose of
passenger traffic. The Stockton and Darlington rail-
way, opened in 1825, gave a very favourable idea of
the great value of railways for the conveyance of pas-
sengers and goods even when animal power was used,
as it was on that line. But the expense of animal
power at a speed of 8 or 10 miles an hour was found
to be great, and as the directors of the Liverpool and
Manchester line aimed at a high rate of speed, it was
proposed to erect fixed engines, at intervals of a mile
or two along the line, and to draw the trains, from
station to station, by means of ropes. Fortunately
for the interests of railways, it was determined to
employ locomotives, and to offer a premium of 500l.
for the best engine: this engine was not to produce
smoke, it was to draw 3 times its own weight at the
rate of 10 miles an hour; it was to be supported on
springs; it was not to exceed 6 tons in weight, or 4.12—
tons if it ran on 4 wheels only, and it was not to cost
more than 550l. Trial of the engines was made in
October 1829, when 4! steam locomotives were pro-
duced, one of which was withdrawn at the commence-
ment of the trial. Of the ‘other 3, the Novelty, by
Messrs. Braithwaite and Ericson, promised good
‘—
results, but an accident with the boiler crippled it
during the trial. The Sam Par-ell, by Mr. Hack-
worth, attained a velocity of 15 miles per hour with
a gross load of 19 tons; but an accident happened to
this engine also, which put an end to the experiment.
The third engine, the Rocket, by liessrs. Robert
Stephenson and Booth, surpassed the stipulated con-
ditions and won the prize.
miles an hour with a gross load of 17 tons, but under
certain circumstances it attained double that velocity.
The experiment thus tried produced the most satis-
factory impression upon the public mind. The possi-
bility of constructing railways in certain situations,
Chat-Moss for example, had even been denied by
engineers of repute, and the attempt to form loco-
motives for moving laden carriages at a high rate of
speed (as 10 miles an hour was then called) had excited
the smiles of scientific men. But now that the'thing
had been done, that a speed far superior to that of
horses had been attained, men scarcely ventured to
limit their anticipations for the future. The traveller,
whether for business or for pleasure, had vivid im-
pressions of the discomfort of a slow and toilsome
journey by coach from one part of the kingdom to
another, and he now ventured to hope that soon he
might be able to travel at the rate of at least 20 miles
an hour! We need not, however, now refer to the
prospect of railways in 1830, since the most sanguine
expectations of that time have been more than real—
ized.1L Railways have spread their civilizing net-work
over the face of the earth, and have been a powerful
means of bringing the human family into closer union;
the system is still extending, and let us pray that its
effect may be to hasten the coming of that happy
time when “the knowledge of God shall cover the
earth as the waters cover the sea.”
Ouzves mzcl G'raclz‘erzla—fThe laying out of a line of
railway is a more important operation than that of a
common road. _ Not only is the railway more costly than

(1) At the commencement of 1851, the length of railways in
actual operation in the United Kingdom was as follows :—
England and Wales 5132 miles.
Scotland .. 951 ,,
Ireland 538 ,,
TOTAL ....... .. 6621 ,,
.—
The lengths of line opened in the following successive years
were :—
1843 (and earlier) . 2036 miles.
1844 204 ,,
1815 296 ,,
1846 606 ,,
1847 803 ,,
1848 1182 ,,
1849 869 ,,
1850 625 ,,
The following is the amount of the traffic :—
Year. _ ‘Total. Weekly average per mile.
1812 £4,341,781 . £60
1843 - ‘£842,625 . 59
1844 5,610,982 63
1845 6,669,224 . 66
1846 7,689,874 ............. .. 62
1847 ............. .. 8,975,671 55
1848 . 10,059,006 49
1849 11,013,817 4+
' 1850 12,775,235 43
Its average speed was let '
548
ROADS AND RAILROAIDS'.
the road, but it must approach more closely to the
definition of a perfect road. The theory of a perfect
railway is, that it shall follow a right line, and be
uniformly level from end to end. There are but few
parts of the world where such perfection is attain-
able ; ‘the presence of hills, rivers, canals, towns, and
depots, and the‘ difference of level at the intended
termini, preventing the formation of such a line.
When the termini and general course of the line
have been decided on, a careful survey is made of the
country to be passed over; its elevations and depres-
sions are carefully noted, together with the roads,
water-ways, towns, &c., that have to be avoided,
crossed, or visited; and the geological structure of
the country must be ascertained. The facts thus
collected will determine what lateral and vertical
deviations from a perfectly straight horizontal line
will be required, or, in other words, what will be the
curves and the gradients. The width of the surface
is determined by the intended gage of the line and
the slopes of its cuttings and embankments. In
order to the proper adjustment of the gradients, a
section or profile of the line of country is pre-
pared, in which the elevations and depressions are
drawn to a much larger scale than the horizontal
distances, so as to make them more appreciable to
the eye by making them disproportionably steep. It
is required under the standing orders of Parliament
respecting railway bills, that plans and sections of
the proposed line, on a scale of '41 inches to a mile,
shall be deposited with the Clerks of the Peace for
the several counties through which it is proposed to
carry the railway, on or before the 1st March, and
in the Private Bill Olfice on or before the 1st April,
in the year preceding that in which an application is
made to Parliament for an Act. The process of ob-
taining a railway Act does not belong to our subject,
but we may state that the Act, which forms the share-
holders into a corporate body, with powers to construct
the line, generally allows a deviation from the line laid
down in the plan to the extent of 100 yards in the
country, but only 10 yards instowns. Power is also
given for altering to a limited extent the levelsand
gradients defined on the parliamentary section. In
this country the laying out ‘of a railway, as well as its
construction, like most other great engineering works,
is left to private enterprise. It has been contended
that a system of railroads should be laid out by the
government of a country, in order to ensure some
uniformity of plan, which shall promote the general
convenience, and yet not cut up the land unneces-
sarily, or conduct lines through dangerous localities.
Most of the continental lines» have been laid out
under government control; although many of them
have been constructed and worked by private com-
panies. . .
The lateral deviations from the theoretical straight
line of a railway can only be made in curves, angles
not being compatible with speed, nor with the per-
manently parallel axes of the 44.‘ and 6-WllG616d car-
riages impelled thereon. As the perfect condition is
a right ' line, so the minimum amount of deviation

therefrom will produce most satisfactory results in
the working; and this minimum deviation can only 1
be produced by making the curves of the largest
possible radius, arranging the line so as to have the
smaller curves near the stations or stopping-places.
This arrangement is necessary not only for speed,
but also for safety. In moving over a curve at a
high rate of speed, the effect of centrifugal force
tends to throw the train off the line. There are also
other objections to curves, which engineers have en-
deavoured in various ways to remedy. For example,
in ‘moving on curves the wheels on the inner rail will
attempt to describe a smaller curve than the wheels
on the outer rail, and will thus be made to rub back-
wards and forwards on the rail while the outer wheels
are getting over the excess of space; this produces
torsion of the axles .and straining of the frame and
the parts connecting it with the axles. Attempts
have been made to remedy this ‘source of evil by
giving a conical form to the tires of the wheel, and
by slightly raising the outer rail. The tires are so
arranged that the bases of the cones are towards
each other, and it is assumed that when the centri-
fugal force drives the flange of the outer wheel
towards the edge of the rail and withdraws the-
flange of the inner wheel from its rail, the diameters
of the wheels are rendered practically unequal in
the exact proportion required to get rid of the
dragging which takes place when cylindrical wheels
of equal diameter, locked together on the same axle,
are made to describe curves. The tendency of the
carriage to proceed in a straight line instead of
a curve is usually counteracted by the rubbing of
the flange of the wheel against the rail: the object
of making a slight ascent to the middle of the curve
is to diminish this forcible friction. The extent to
which these two corrections are applied may be
illustrated by the following example given by De
Pambour :—With an average velocity of 20 miles an
hour, a radius of curvature of 500 feet, the wheels 3
feet in diameter, the gage of the railway 4'7 feet, and
the play of the wheels between the rails 2 inches, the
least inclination that should be given to the tires of
the ‘wheels is 1-12-th; that is, the tire should belong to
a cone the radius of whose base is to its axis as 1 : 12.
It is usual to give an inclination of -;ith. With the
same data the outer rail of the curve should have
a surplus elevation of 2'83 inches. _
At or near the termini and junctions, which are
always approached and departed from at a‘ very dimi-'
nished speed, curves of small radius may be used.
On the Chester and Orewe line, the Grewe terminus is
quitted in a curve of 18' chains radius ; and the Grand
Junction joins the Liverpool and Manchester line in‘
two curves of 10 chains radius each. Such curves?
as these cannot, however, be commended even at
stations, for it is necessary in order to allow mail and
other trains to pass first and second-class stations at
'fullaspeed, that the largest possible curves be adopted
throughout the line. - I ~ > '
The. deviations 'from the ‘horizontal level form the‘
inclinations or gradients of the railway. These must-
ROADS AND RAILROADS.
‘549
be considered with reference to economy in the con-
struction of the line,—-as to how much earth-work,
tunnelling, bridge-work, 860., may be saved consistent
with the required velocity, the expenses of engine-
power, the wear and tear of engines, carriages, and
brakes. Where the gradients are steep the cuttings are
required to be of less depth, and the embankments of
less height; a smaller quantity of land is required, and
the ratio of saving, both inland and labour, increases
rapidly upon the proportion of height or depth avoided:
there is also a large saving in the size and cost of
bridges and cuttings, and bridges or viaducts under
embankments, &c. But, as' already stated, it must
be considered how far these sources of economy in the
first cost are counterbalanced by increased expense in
locomotive power, repair, and economy of time. The
opinions of engineers are much divided on the subject
of gradients. It has been stated that an elevation of
20 feet requires an exertion of force equal to that
on a mile of level railway; so that the same power
which would move a given load over one mile of rail-
way rising 1 in 264, or 20 feet in the whole, would
move the same load over 2 miles of level road. An
other view of the case is, that an alternation of steep
and easy gradients is as advantageous as a gradient
of medium steepness, the rise being the same in both
cases. If this be so, the important fact is established,
that it is not necessary to spend vast sums of money in
reducing hills and filling up valleys, at least to such
an extent as has been done on many of the great lines,
for the purpose of making the gradients as easy as
possible.1 The advocates'of the system of alternating
steep with easy gradients, or with levels, maintain that
a compensating effect is produced in descending and
ascending gradients, and that a variation of speed
in the train is the whole amount of inconvenience
that will ensue.
In confirmation of this view of the case we may
refer to some experiments made by Dr. Lardner in
July, 1839, when the Hecla engine with 12 carriages,
making altogether a gross weight of 80 tons, was run
from Liverpool to Birmingham and back in the same
day; by which means the same train, under as nearly as
possible the same circumstances, had to ascend and
descend every plane on the line for a length of about
95 miles. The time of passing each quarter-mile was
carefully observed, so as to obtain the speed on'every
part of the road. The following table gives the
results of observations on gradients varying from a
level surface to 1 in 17 7, or nearly 30 feet per mile :-—

Speed in Speed in
ascending. descending. Bled-n speed.
Gradients, llfz'les M z'las files
1 in per hour. per hour. per hour.
177 22-25 41'32 31'78
265 2487 3913 3200
330 25 26 37-07 31'16
400 26'87 3675 31 '81
532 27-35 3430 3082
590 2737 3316 3021
650 2903 32-58 3080
Level -——-— 3093
(1) It has been calculated that the railways existing in 1842 had
cost on an average about £34,700 per mile; in 1846 this average
was estimated at £31,800, and at the end of 1850 £35,200.

Thus, taking the velocity on the level surface at 31
miles per hour, it will be seen that this rate was
lowered to a little over 22 miles an hour in ascending
an incline of 1 in 17 '7 ; but the increased rapidity of the
descent more than compensated for the loss, the mean
velocity being 317 8. The mean speeds on the dif-
ferent gradients vary slightly, but the result of this
interesting experiment seems to show that a line of
railway with gradients of from 20 to 30 feet per mile,
may be worked in both directions by the same expen-
diture of power as a dead level. We do not give
this as an established conclusion, but refer to it as an
interesting subject for inquiry. Although some of
the most eminent engineers have expressed themselves '
strongly in favour of easy gradients, a plan has been
getting into use which accommodates both steep and
easy gradients, and vastly diminishes the cost of con-
struction. This plan is, to accumulate the ascents as
much as possible into short steep planes, which are
to be worked by means of assistant engines, either
motive or stationary. Although by this plan there is
no saving of power, there is a saving of time, and it
is not necessary to reduce the amount of load below
what would be otherwise considered most advan-
tageous for the general traflic. Whereas with steep
gradients, not accumulated, but distributed over the
line, the engines must work with small loads. For
example, in ascending a plane of 1 in 1410 with a load
of 100 tons,the-force of traction requires to be doubled,
or be made equal to 200 tons on a level. Or, in'order
that the engine may ascend the plane without assist-
ing power, the load must be reduced to 60 tons; the
expense of haulage up the incline is increased 36 per
cent: so that not only is the equivalent horizontal
plane about one-half longer thanthe real length of
the actual plane, but the expense of working the
whole distance is increased 36 per cent.
In answer to this case, which was given in the
Report of the Irish Railway Commissioners, Mr.
Vignoles states as the result of his long experience,
that scarcely once in 20 times does a locomotive engine
go out with more than half its load, and in general,
engines are only worked 'up to -§-ths of their power.
He therefore states his conviction that it is cheaper
to put on an additional engine’ on extraordinary occa-
sions, and hence that railways should be constructed
through the more remote parts of the country so as
to be made in the cheapest manner, that is, not to
attempt to produce very easy gradients.
Whatever be the ratio of inclination for the gra-
dients, it is necessary for the sake of economy, safety,
and convenience in working the line, that the gra-
dients contiguous to stations should always rise
towards them in either direction, so that every station
may occupy the summit of two adjoining gradients.
By this arrangement an impetus is given to the
engine in starting, and a salutary check is afforded to
the speed of the engine and train 'on' arriving at a
station; ‘thus rendering unnecessary the action of a
powerful brake, which is as destructive to. the wheels
of waggons as it is to the rails. The value of the
incline in starting the engine is very great, since every
550
ROADS AND RAILROADS.
‘the same.
engine in starting has to exert an additional effort: _
when motion is once created the moving power need
only be constantly equal to the resistance; but in
putting the mass into motion, the power must exceed
the resistance; for in one case it is only necessary to
maintain the speed; in the other it must be created
and maintained. The difficulty in starting is always
great for considerable loads, and hence the value of
a slight declivity. It is advisable to separate long
inclines of considerable steepness into two or more,
lengths by the introduction of short planes, either
level, or inclined inopposite directions. These breaks
‘or dens/res, as they are called, act as resting-places to
"the loaded engines, giving the driver an opportunity
of easing the steam-pressure in-ascending, and serving
to moderate the speed in descending.
The speed of a railway-train creates as it were an
opposing power in the resistance of the air; but the
retarding effect due to its displacement has not been
correctly ascertained. The “ Second Report on Rail-
way Constants,” presented to the British Association
at its eleventh meeting, contains some interesting
experiments on this subject. It was found that with
a train of 8 carriages moving with a velocity of 30
miles per hour, the resistance to the speed was about
15lbs. per ton, or almost double the value of the
resistance from friction only.
external configuration on the resistance of the air, the
Committee concluded from their experiments “that
the form of the front has no observable effect, and
that whether the engine and tender be in front, or
two‘carriages of equal weight, the resistance will be
The intermediate spaces between the
carriages were closed in by stretching strong canvass
from carriage to carriage, thus converting the whole
train into one unbroken mass. The results were in
favour of the train without canvass, but the differences
are extremely slight: it is certain that no additional
resistance is occasioned by leaving open spaces
between the carriages, confining the intervals to the
dimensions allowed in practice.”
Gage of Me Line. The determination of the gage,
or width between the rails, is a point of great import-
ance, for on this width depends to a certain extent
the kind of locomotive which can be used, the size of
passenger-carriages, the bulk of merchandise and
goods that can be conveyed, the steadiness of mo-
tion, and the safety and facility in passing round
curves at high rates of speed. The gage has also an
influence on the quantity of land required for the
line, on the width of bridges, viaducts and embank-
ments, cuttings, tunnels and stations.
There are 3 widths of gage in England, viz. 411.661;
8-12— inches, 5 feet, and 7 feet. There are 2 widths in
use in Scotland, viz. 4! feet 6 inches, and 5 feet 6
inches. There is yet another gage in Ireland, viz. 6
feet 2 inches.
Previous to the formation of the Great Western
Railway the gage in use in England was 41 feet 8 5-
inches. Brunel made the considerable increase of 2
feet 3% inches, on the ground that the 7 -feet gage
would allow of an increased speed, in consequence of
As to the efi'ect of '

the employment of larger ‘and more powerful engines ;'
of diminished friction owing to the larger diameter of
the wheels; of increased stability and steadiness
from the method of placing the body of the carriage
within the wheels, whereby the centre of gravity of
the carriage would be kept low; of increased accom-
modation for the conveyance of bulky goods, &c.
In opposition to these advantages have been opposed
the increased cost of the line; the larger and heavier
carriages and their increased cost; the additional
friction in passing through curves, and the greater
liability to the fracture of axles; and, lastly, the im-
possibility of forming a junction with other lines.
Slopes, (,tttt‘z'rzgs, and Emdmz/rmenta—The inclination
of the earth-works, whether for excavations or em-
bankments, must be determined mainly by their
height, and the nature of the material excavated, or
of which the embankment is composed. .In stratified
rocks, the tendency of one stratum to slip upon
another, requires that the slopes shall be much less
steep than would be safe in unstratilied materials.
The slipping of one stratum upon another may be
caused by the passage of water, or by the action of
frost between the strata, and can only be prevented
by draining the faces of the cutting and extending the
drainage backwards for some distance, so as to collect
all the water that may find its way into the neigh-
bouring soil, and carry it off before it has time to get
to the face of the work. A complete system of
superficial drainage must also be provided for the
water that collects on the surface of the cutting.
Probably the worst kind of stratification which the
engineer has to encounter is an alternation of sand
and clay. When these materials are mixed, the work
is safer. Stony soils, or a mixture of sand and gravel,
become compact and hard. In passing through rocks
the excavation may be formed with steep sides ; but
if the rock be liable to disintegrate by moisture or
by frost, a greater flatness must be allowed. Chalk
may be out with nearly vertical faces, its own cohe-
sion being sufficient to support it. In general it will
be found that an angle a few degrees less than that
of repose, will answer both the conditions of economy
and stability, and a little extra attention to drainage
will be cheaper than giving additional flatness to the
slopes. The banks must be preserved with care by
covering them with turf or with the surface soil, and
they must be sowed with grass seeds. Spade-cuts or
channels passing obliquely from the summit of the
slope to the drain at the base, so as to form a re-
peated outline of the letter V on the face of the
bank, the V’s in some cases intersecting, will form
cheap and efficient superficial drains,
In cases where shale, or other soft stratum lying
under stone, such as limestone, is found to rise above
the level of the bottom of the cutting, a portion of
such shale or soft stratum is to be excavated from
under the limestone on each side of the cutting, and
be replaced by walls, buttresses, arches, and inverts.
The excavation at Blisworth, on the North Western
Railway, furnishes an instructive example of this
kind of work. The principal excavation is about 126
.ROKDS ‘AND “
‘551*
RKIL'R‘O ADS.
chains in length, and 53 feet in its ‘greatest depth.‘
The strata intersected are the upper soil s s, Fig. 1860,
of a light sandy kind, with clay from 2 to 10 feet thick,
and ‘lying mainly in blue, yellow, and brown marl, and
red clay, of an average thickness of 20 feet. Under
these is the limestone rock an, of various degrees of
hardness, and in beds of 1 to 41 feet in thickness, but
without any mixture of shale, and having springs of
water in the lower beds. At the east end of the
section the limestone rock crops out, and the superior
stratum of marl disappears. Beneath the limestone
is the blue shale: it appears to be dished on the
upper surface, being about 6 feet thick at the east
end, extending about 20 chains, then ranging beneath
the railway level, rising again at the end of 75 chains,
and acquiring a thickness of nearly uniform increase
of 30 feet at the western extremity of the section,
where it outcrops beneath the limestone.
At the west end the excavation is formed to a slope

of 2 feet base to 1 foot height throughout its whole







. \3 \
\ ‘ \\\\
i\\\= -
\g \\ \~‘_§\:\\\~\\%x\\\\_\\ { \\ ‘ \
x ‘1.1 t” \l
x . \ I’ b‘ ‘\\".“. ‘\ \\‘
T‘a\ i “We h
“‘--§\*?‘"_§ "31,9353~_,_\<"\5 \
.Fz'g. 1860.
depth for a distance of 22 chains, the inferior stratum
of shale being faced with rough stones. Through

Fig. 186].
the next distance of 38 feet the opening is narrowed
by a winding Miter 1 on each side, to a section corre-

( 1) Probably from the French verb bzitir, to build.
or
a‘.
.. . r
\\\\\~ .\

sponding to that. shown in Fig/1860' The lower
part, extending upward to a height ranging with the
undersetting of masonry beneath the rock, which is
continued throughout the excavation, is formed to a
curved batter of 106 feet radius. The average verti-
cal height of this undersetting above the level of rails
is 20 feet. The rock above is sloped at 1;— to 1, a
benching of 9 feet wide being left on its upper surface,
and the superior soil trimmed to a slope of 2 to 1.
The method of draining is also shown in the figures,
together with the inverts I and buttresses B for sup-
porting the undersetting. F 1860 is a cross section,
one half being taken through the wall, the other
through one of the buttresses. Fig. 1861 is a sec-
tional plan of half of the excavation, showing the
recess wall, 2 feet 6 inches thick at top, battered in
front to a slope of 2 inches to 1 foot. The centre
drain 1), 1 foot 9 inches wide; and the cross drains (Z (Z,
are shown in section. 12 1? shows the pitching and I r the
invert arches. Midway, between each 2 contiguous
buttresses, a vertical drain, or gullet, d,
_ is formed on the face of the wall, re-
4 ' ceiving the drainage water by oblique
drains, shown in dotted lines, from the
puddling 12 at the back of the wall.
The quantity of material removed
from some cuttings is enormous. Thus,
to cite a few examples :-——the Oaken-
shaw cutting on the North Midland
railway is in rocleshale and bind: the
greatest depth is 50 feet, and its con-
tents 600,000 cubic yards, most of
which was led to form the Oakenshaw
embankment. The Normanton cutting
has a maximum depth of 55 feet: it
contained 500,000 cubic yards, chiefly
rock, and blue bind : most of this was
led to form the Altofts embankment, and
70,000 cubic yards were thrown out “ to
.. \s; '
, Q?\- r
~\_\\\,\\ v.
- \
\\\\
l/fifil
\\‘\=-
n
I spoil.” The progress of the works was so rapid in 1839, ,
that 450,000 cubic yards of excavation were effected
per month. The number of men employed was 8,600,
and there were 18 fixed engines working chiefly at
tunnels. Much trouble and expense are occasioned
by the slipping of the slopes. In a cutting which
was to be formed in the side of a hill in the north of
England, it was calculated that about 50,000 cubic
yards of earth would have to be removed. It hap-
pened, however, that the soft earth was upheld by
a seam of shale, which was no sooner cut through
than a mass of earth slipped down into the line of the
railway, to such an extent as to require the removal
of about 500,000 cubic yards.
In excavating through hills of considerable height,
it is important to get a fair face to the work, or one
at right angles to the direction of the cutting, and
from this face to start a system of gullezfz'rzg or note/z-
In this way labour is economised. As the work
proceeds into the hill, and the width is increased in
order to provide for the slopes, it is desirable to run
a gullet along the centre of the cutting, in order to
bring a larger number of waggons into use at one
552
norms AND nslnnoxns.
time. In this gullet temporary rails are» laid down,
and the train of waggons is sent forward to receive
the produce of the harrowing on either side. As the
height of the hill increases, a second layer is com-
menced, and a side track is laid, inclining down on
each side of the lower level. On these lines the full
waggons. descend on one side, and the empty ones are
drawn up by horses on the other. Horses are also
used for moving the full. waggons to the head of the
incline, down ‘which they descend by their own weight.
One of the great inconveniences of excavating is the
accumulation of water in the lower parts of the cutting:
this is prevented by keeping the bed of the cutting
inclined upwards so as to conduct. the water away.
When the leaal is in both directions from the centre
of the intended excavation, and it is required to send
the materials-got out to each end of the hill, the ex—
.cavation is begun at both ends and terminates in the
middle: in such case there is a rise from each end to
the centre for the purposes of drainage. In many
cases the plough is used preparatory to excavation:
it is very effectual in loosening the surface. In
America a scoop has been'found of advantage.
In so extensive a work as a railway over an undu- -
lating surface, it is of great importance that the
amount of excavation and embankment should be
balanced as nearly as possible, to prevent the necessity
of depositing the earth from cuttings in spoil-54mins,
or of having to purchase land for furnishing material
for embankments. If a cutting were found to yield
a surplus of material, a short tunnel would be pre-
ferable to a cutting; but if material for embanking
be wanted, then the cutting would be preferable to
the tunnel. It is generally contrived, for the sake of
economy, that a cutting and an embankment shall be
carried on simultaneously; but ‘the cost of the em-
bankment will be considerably influenced by the length
of the lead, or the distance to be traversed by the
earth-waggons between the points ,of filling and
emptying. The usual and quickest mode of forming
an embankment is by running it out to the full depth
required at-once. The front end of the embankment
where the formation is proceeding, and over which
the material is lippecl, is called the dailerg/Jieacl. Tem—
porary lines are laid down with edge-rails and wooden
sleepers, in a double’ line, with crossings near the
batterydhead for the waggons to cross overas soon as
they have tipped over their contents, when they
return to be filled by one line, while the full waggons
are proceeding along the other.
The method of forming embankments for common
road-s has already been noticed. The subsidence of
newly-made embankments, in some cases leads to con-
siderable expense and even danger. There are various ,
methods of embanking,'that method being the best‘
which combinesv stability with economy. With this
view many engineers prefer to run forward the two
sides of the-‘embankment to the full width, leaving a
central valley to be filled in at some little distance in
the rear.’ ‘The effect‘ of this arrangement is, that the
two sides act- as separate embankments, and resist
the thrust of the central part afterwards put in; and

any alteration in form and position is less likely. than
if the banks were carried forward with one battery-
head across the whole width of the work.
The kind of waggon employed in embanking de-
pends tov some extent upon the material. Those
called earl-waggons, Fig. 1862, discharge their load
from the back or end; side-waggons are emptied at the
side. The waggons move on a hinge, and by the
motion of a lever are tilted or tipped over as soon as



Fig. 1862.
the wheels strike against a fixed stop or bar at the
battery—head. Fig. 1863 shows a form of waggon
which is more readily emptied than when the body



'0
'r
,o



Fig. 1863.
turns on airing-e. The body is supported on 2 rollers,
and when the waggon suddenly stops at the tip, the
momentum of the load carries the body forward until
its centre of gravity gets beyond the support, and the
body is instantly tilted. The body is prevented from
overrunning by a pair of curved metal stops, which
are checked against the front rollers. All the waggons
are provided with simple brakes, consisting of a block
of hard wood, shaped so as to fit a portion of the
periphery of the 12 wheels, and capable of being turned
on a centre by means of a long handle of iron which
is carried to the front or bind part of the waggon, so
as to be acted on by the hand or foot of the, brakes-
man. The handle moves within an iron slot, and‘may
be secured in any position by a pin passed through it.
The earth-waggon is nearly square in form, having a
slight taper or increase of width towards that end of
the waggon which is turned downwards in the act of
tipping. Each waggon contains, about 2% cubic yards‘:
the wheels are 3 feet in diameter; the wood-‘work is
IROADS AND RAILROADS.
553
of English elm. Under the framing a sole should
project beyond the body to leave room for the driver
to escape in case the sole ends or buffers should be
forced violently together. Waggons are also con-
structed of iron.
One of the most celebrated embankments is that
over Ohatmoss, on the Liverpool and Manchester line,
formed in the infancy of railroads, and in opposition
to the opinions of eminent engineers as to its practi-
cability: some declaring before a parliamentary com-
mittee that it would be utterly impossible to carry a
line over this bog without first cutting down 33 or 3A
feet to the solid bottom; others declaring that a cost
of 200,000Z. would not suffice for the work: and yet,
although the moss contained nearly double its bulk of
water, a safe embankment was formed over its surface
at a cost below the average of other parts of the line.
The tribute of respect paid to the engineer of this
great work by a celebrated French writer,1 will be
a sufficient excuse for quoting the passage :—
“ The depth of the moss varied from 10 to 34 feet,
and its general character was such that cattle could
not walk on it: the subsoil was principally composed
of clay and sand, and the railway had to be carried
over it upon a level, and required cutting and em-
bankment for upwards of 4! miles. Where the mode
of doing this required an embankment, the expense of
which, in the ordinary method, would have been enor-
mous, as it must have been bottomed upon the subsoil
of the moss, Mr. Stephenson contrived to use the
moss itself in the following manner :—-Drains about
5 yards apart were cut, and when the moss between
them was perfectly dry, it was used to form the em-
bankment, and so well did it succeed, that only about
4.1 times the quantity was required that would have
been necessary on hard ground. Where the road was
on a level, drains were cut on each side of the in—
tended line, by which, intersected with cross ones
occasionally, the upper part of the moss became dry
and tolerably firm: on this hurdles were placed, either
in double or single layers, as the case required, 4! feet
broad and 9 feet long, covered with heath; on these
was laid the ballast, and the method was fully success-
ful. Longitudinal bearings, as well as cross sleepers,
were used to support the rails where necessary, and
the whole was thoroughly drained. In the cutting,
the whole had to be accomplished by drainage entirely.
Longitudinal drains, about 2 feet deep, were cut on
each side of the intended line of railway, and when by
this means the upper surface of the moss had become
dry, about 12 or 15 inches in depth were then taken
out, as in an ordinary case of excavation; the drains
were then sunk deeper, and another portion taken
out when dry, as before; and thus, by alternately
draining and excavating, the depth required for the
railway was attained, which in some instances was 9
feet, the embankments being as high as 12 feet. The
only advantage in favour of these operations was, that
the surface of the moss was higher than the surround-
ing country, which partially assisted the drainage;

(1) Leconnt. “ Practical Treatise on Railways,” 1839.

but when it is considered that, from the nature of the
ground, an iron rod would sink by its own weight,
it must he confessed that such an undertaking as car-
rying a railway along, under, and over such a material,
would never have been contemplated by an ordinary
mind. In a smaller moss, which had also to be crossed,
and which was about 20 feet deep, although an em-
bankment of only 4! feet high was required, the clay
and gravel tipped amounted to as much as would ,
form one 241 feet high on ordinary ground.”
In districts where stone is plentiful, the method of
forming embankments and cuttings, shown in Figs.
1864', 1865, may be economically adopted. The em-
bankment, or lower part of the cutting, is faced with
rubble-work with a batter sufficient for its stability.
On the Leeds and Selby line this facing to the em-
bankments has a curved batter, the chord line of which
forms an angle of 67° 30’ with the horizon. These
embankments must be provided with strong parapets P,

Fig. 1864.
to prevent the train from falling over in case it should
run off the line r r. When this occurs on the edge of an
embankment formed of soil, and sloped at 2 to 1, the
train would probably be arrested by sinking in the
yielding material, which would evidently not be the
case in embankments faced in this manner, with steep
sides. In this method there is much economy in the
amount of earth-work to be embanked, and in the
width of land required; it also gives great facility of
drainage and ensures stability. An open longitudinal
drain or channel 0? being formed behind the parapets,
and made to communicate with vertical or oblique
channels formed on the face of the stone-work, con-
ducts all the water to the toe of the embankment,
whence it is readily withdrawn by side ditches. The
slope of the earth-work above is also eficiently drained
by a longitudinal channel 1) n behind the top of the
facing, connected either with channels on the face, or
perpendicular drains behind, with cross drains leading
into the centre one o n, as shown in Fig. 1865.
The effectual drainage of the artificial works con~.
nected with a railway is of the utmost importance.
The failure of many earth-works is to be traced to
that secret and insidious enemy, water. Whenever
about the works it is even suspected to exist, it
should be traced to its source and diverted from
slopes and adjoining surfaces. Beneath embankments
every stream should be intersected, and every field,
ditch, or other natural or artificial water-way, should
55$
RQADS AND RAILROADS.
be connected with drains and culverts, for the safe‘
and effectual conveyance of water from the work.
The size of the culvert must of course depend on the
quantity of water to be removed : it must be built in
before the embanking is commenced, and be left for
some weeks at least to consolidate before it is covered
in. Good drainage is also necessary for embankment
walls: retaining walls are liable to fail, from the satu-
ration and consequent swelling of the‘earth behind
them.
The method of forming ;tunnels will be noticed
under a separate head. [See TUNNEL]
Bridges arid Viadaois. —- Having, in our article
Bnrnen, entered, into full details respecting the con-
struction of various kinds of bridges, it is not neces—
sary to go into the‘ construction of railway bridges
and viaducts, although many of them present peculiar
features, such as cast-iron girder bridges, the girders
being laid from one abutment to the other, and sup—
porting a platform of flag-stones, iron plates, or planks
of wood. When the railway passes over such a bridge,
six ribs or girders are used, 41 of which sustain the
rails, and ‘the other 2 the parapets, a light flooring of
iron plates being constructed between the girders.
This arrangement gives great strength, and super-
sedes the “necessity ‘for ballast, thus reducing the
depth or thickness of the bridge to a minimum. In
order to preserve the straightness of the railway,
s/rezo bridges are required at points where the railway
intersects any existing communications at an oblique
angle. Hence, in crossing such a road by a skew
bridge, the communications over and under the bridge
form unequal angles with each other. Many beautiful
examples of brick and masonry-work are afforded by
these ingenious structures.
The Britannia tubular bridge is fully described
under BRIDGE. Another structure, equally remarkable
in its way, is the liigli-leoel bridge at Newcastle-upon-
Tyne, which forms the junction between the York and
Newcastle, and the Newcastle and Berwick railways.
This bridge was projected by Mr. Hudson, and de-
signed by Mr. Robert Stephenson: it extends from
the castle-garth on the north, to the high ground on
the south side of the river. There are two roadways,
one level with the castle-garth, for carriages and foot-
passengers, and the other at an elevation of 22 feet
above it. The carriage-road-is 1,380 feet in length on
a straight line. 'The bridge-is 1121;,» feet from high-I
water line to the top of the parapet, and the roadway
is 80 feet above the water. Six arches, each of 125
feet span, form the bridge,——the piers upon which they
rest being of masonry, and the arches, pillars, braces,
and transverse girders, of iron. The bridge-piers are
nearly 50 feet by 16 feet in thickness, and in extreme
height are 131 feet from the foundation, having an
opening in the centre through each. They are erected
on piles, which pierce the bed of the river, about
50 feet on the north side, and 20 on the south.
The land—arches of the bridge diminish in altitude
from the foundation upwards, corresponding with
the steep bank of the river. The roadway for
vehicles beneath the railroad is suspended from the

great arches which carry the line; “ and it is scarcely
possible to imagine a more interesting or beautiful
sight than it presents, with the huge span of the
arches diminishing in perspective, and the opening at
the furthest end of the bridge, showing only like
a bright spot in the distance. The pillars, which
carry the road, add greatly to the picturesque effect,
and the multiplicity of column-ribs, transverse and
vertical braces, produces such a; combination of beau-
tiful lines, as is seldom seen.” 1
We cannot quit“ this part of our subject without
offering a remark on the extraordinary number of
bridges and viaducts which occur in British railways.
It was ascertained in 18417 that, for every mile or
railway constructed up to that time, from 2 to is
bridges had been built, many of "them not more single-
arch bridges, but viaducts of hundreds of feet in
length, and of great height, solidity, and cost.
T/ze permanent zeag.-~When the top surfaces of the
embankments, bridges, and viaducts, and the bottom
of the cuttings, have all been made to correspond
with the intended level of the line of railway ; or, in
other words, when the formation level has been pro-
duced, the construction of the permaaeal wag may be
commenced. The permanent way includes a surface—
covering of ballast, in which the sleepers are to be
embedded: if the sleepers are laid transversely to the
direction of the railway, they support chairs for carry-
ing the rails; but if the sleepers are laid longitudi-
nally, the rails are bolted down at once upon them
without the use of chairs, and with the intervention
of a piece of tarred felt, or of vulcanized India-rubber
only. Provision must also be made for communicating
between one line and another by means of crossings
and turnplates, &c., for the passage of engines and
carriages.
The ballasting, which should be from 18 to 2d
inches in thickness, consists of very various materials,
such as can be most readily and cheaply procured.
Those in common use are burnt clay, burnt marl,
rock marl, gravel, broken sandstone and has, oolite—
stone, &c. Loam does not afford a good ballast, but
a mixture of chalk and flints is good, or a mixture of
sand and broken stone ; gravel and broken limestone
form a good binding material, but gravel alone, or
‘gravel and sand, or broken stone alone, does not bind
well. Sand is very objectionable as ballast; it is
raised ‘up by the wind or by the draught occasioned
by the velocity of the train, settles among the bear~
ings, and gets between rubbing parts, cutting and
wearing them away in a very remarkable manner.
Cinders, or- small coal, are used as ballast, where
these materials are abundant. Where stone is plen-
tiful, the whole line is sometimes pitched transversely
with thin stones, and on this a bed of broken stone
is spread for ballast, after Telford’s plan for common
roads. '

(I) “ Our Iron Roads, their History, Construction, and Social
Influences.” By Frederick S. Williams. 8vo. London. 1852.
(2) Probably so calledin contradistinction to the temporary way,
which is laid down in the first instance to facilitate the construc—
tion of the line.
. u . x4 ‘.1.
, ._ .5. .IT. who Z .5
In ~>sr

ROADS ' AND RAILROAD S;
55'?)
The foundation of the permanent way is, now
formed of timber. Formerly, as noticed in our histo-
rical sketch, blocks of stone were laid down, either
square with the railway or diagonally, for the recep-
tion of the chairs for holding the rails ; but the weight
of the passing train tended to thrust them asunder,
and thus to disturb the gage of the line. The weight
of the blocks was also found to disturb the stability
of bridges and other constructed Works. Timber,
therefore, again came into general use, and is now
preferred. It is first prepared by kyanizing, or im-
pregnating it with certain saline substances, a process
which is said to confer on soft wood the durability of
oak. Timber is used for the cross sleepers of sufli-
cient Width to support a pair of chairs, as in Figs. 1866,
1868, or it is used in continuous longitudinal lengths,



to which the rails, formed with bottoin flanges for the
purpose, are at‘ once bolted, as in Fig. 1869, without

. _, "';-.-;»_I3F1?TT _
_n I -. ;__;_'_.;._;._._l": ‘-. 71-... .. . J. " - A?“ n ._'_ Cl‘
\ \ . _ \ NM“ - -_ \ V_ . H
“g ‘~~.\ ‘‘ \\e \V \ \_\.\


Fig. 1868
the intervention of chairs. These longitudinal tim-
bers are connected by cross ties, halved or dovetailed



Fig. 1869.
into them. The continuous hearings were adopted
by Brunei for his wide or 7-feet gage, but they have
also been applied to many narrow gage lines.
For the 41 feet 85 inch gage the cross sleepers s are
half round logs of beech, Scotch fir, or larch: each

log is from 7 to 9 feet in length On the“ South
Eastern Railway the sleepers are of Baltic fir, cut
from square baulks, each being divided diagonally into
41 triangular sleepers. They are laid with the right
angle downwards, and thus present as large a sur-
face for the chairs as the half baulks, and offer‘ great
facility for packing the ballast. See Figs. 187 4:, 187' 5.
The distance between the cross sleepers should be
some aliquot part of the length of the rail: it should
not exceed 3 feet 9 inches, unless a very heavy section
of rail be used. With a 15-feet rail the distance of 3
feet is often allowed, and is said to give greater steadi-
ness and equality of motion; and in some cases 2 feet
6 inches has been adopted for a light rail and a small
chair. Taking all the variations at present adopted,
rails are laid on supports at 3 feet ; 3 feet 6 inches 5
3 feet 9 inches; 4! feet; and '11 feet 6 inches asunden.
Various sections of rails are’shown in Fig. 1870. The


_Fz'g. 1870.
double T‘ rail, No. 3, is a very common form on many
railways with the 4 feet 8% inch gage. The single T
section, No. 5, is also used on several lines. Varia-
tions of these two forms are shown in Nos. 1, 2, and
‘7. In some rails, such as No. 8, the top surface is
curved to correspond with the tire of the wheel.
Bridge-rails, Nos. 10 and 11, are used with longitu-
dinal sleepers, to which they are bolted by ‘bolts
passing througlrrthe lower Webs or flanges. Nos.
41 and 9 are a combination of the T rail with the broad
base of the bridge-rail, and also admit of being bolted
down on longitudinal sleepers. The other rails are
supported in iron chairs, Fig. 1866, to which they
are secured by means of wooden keys, Fig. 1871, or
other means. Fig. 1871 is the chair of the North
Western and other
lines where double
T rails are used. The
space for the rail is
straight on one side,
but curved inwards
on the other. The
flange of the rail en-
ters into this curved
recess, and the space left between the straight cheek
of the chair and the other side of the web of the rail,
is occupied by the wooden key or wedge driven in until
the rail‘ is firm in the chair. After dry weather the
keys shrink and become loose, and require a few
blows with a mallet to tighten them. This incon—
venience is remedied by compressing the wood before
it is inserted, for which purpose the oak keys are
steamed, shaped, and then forced through an iron


Fig. 1871.
5516
ROADS AND RAILROAD $1‘
admit the, key before compression.
block 10 inches thick, containing 12 holes, each Talgths
inch smaller than the key, and tapering so as to
The keys are
forced through the block by the ram of a hydrostatic
press. Some rails are rolled with a notch in the side,
into which a. ball-key or other projection is driven
.from the chair to prevent. the rail from rising. This
‘arrangement is; shown in Fig. 187 2. A cylindrical
hole is made through one of the cheeks at such a
height as will correspond
with the position of the
notch in the rail when sup-
ported in the chair. Through
this hole a small iron ball is
I introduced; a split key is
_ Fig. 1872.‘ then driven through the hole
in the cheek, and crossing the groove in which the
.ball is placed, forces it into the notch of the rail: the
latter is thus confined in position vertically, but it has
a longitudinal motion, adapting it to the varying
dimensions arising from changes in the temperature.
Iron keys of various forms and arrangements have
been introduced from time to time. Mr. Barlow
uses hollow metal keys or pins, the elasticity of
which is, said to be advantageous.
The use of cast-iron chairs entails a loss from
breakage during the fixing and keying. Wrought-
iron chairs have been made by rolling the iron to the
required form in lengths, and cutting up the lengths
into. chairs, and drilling and completing each one
separately. Cast-iron chairs, however, are most com-
,monly used, on account of their greater economy. The
'forms of these are very numerous, and are being con-
tinually increased. Mr. Barlow has introduced a cast-
iron chair and sleeper,




\\\ 5‘ ‘9%’? the eil'ect of which is
to produce great hard-
.lllI;muggiyymlllllll1*~ ness and rigidity in the
line which he maintains
Fig, 1873. 7
ought to be the condi-
tions of a railway, in opposition to elasticity. Fig.
1873 shows Mr. W. Brunton’s combined cast-iron
chair and sleeper.
Fig. 187 4! is a very common form

wedge and trenails: the adjusting gage used in the
fixing‘ is also shown._ Fig. 1875 shews the mode of
fixing the chairs, with the instruments used for boring
the trenail holes. Mr. Dockray recommends that
bridge-rails shall be laid down as shown in Figs.

1876, 1877 : the rails are bolted at the joints, and on
the intermediate cross sleepers, and where the rails
meet there is a wrought-
iron shoe: a uniform
inclination or cant is
given to the rails, and
the mode by which they
are fastened down is
very secure. Figs. 1878,
1879, represent the
form of chair and the
arrangement of the rails at points and crossings. Fig. 1880 is a form of Fig- 1375-
chair adapted to the double rail.





Fig. 1876.


In fixing the joints of the rails allowance must be
made for temperature, which, in a range of 7 6° Falnz,
will cause a difference in length, in a 15-feet rail,
of about Tgth inch. A scientific friend informs us
that he once saw on the Northampton line, where
the ends of the rails butted too closely together,
several yards of the rail-
way raised up by the
heat of the sun into a
ridge about 2 feet above
the level of .the rail. The
sleepers were torn up,
and much damage done. The line had been opened for
an excursion train, which had ‘not yet returned, so
that the line had to be hastily repaired, and in order
to accommodate the increased length, the rails were
laid down again in a curved form. In laying the
rails some attention should be paid to the tempera.
ture, or too much, as well as too little allowance may
be made for expansion. If too much allowance be
made and the joints are square, the carriages are ex-
posed to shocks and jolts. Concussion from this
cause may be avoided by inserting a piece of wood
between the ends of every two rails ; the wood ex-
pands as the iron contracts.
The rapid increase of traffic upon the great lines of
railway is strikingly illustrated by the‘ increase in


Fig. 1880.
weight and strength which has been 'made from time '
to time in the permanent way. The. rails originally
laid 'down weighed 35 lbs. a-yard, and this strength
was considered to-be superfiuously great: ‘experience,’
‘ROADS AND RAILROADS.
557
however, led to the replacing of these by others weigh-
ing 50 lbs. a yard; but even these were not found suffi-
cient for the increasing traffic, and they were taken
up and replaced by rails weighing respectively 62 lbs.
and 65 lbs., a further increase was made to 72 lbs.
and '75 lbs., and the last rails that have been laid
down have weighed 85 lbs. These changes have been
and are being made gradually, so that on some of the
railways at ,the present time the rails are of various
weights, the lightest being 60 lbs., and the heaviest
85 lbs. per yard. For example, at the commencement
of 1849, on 438 miles of railway, placed under the
direction of the North Western Company, there were
about 150 miles laid down with rails of 7 5 lbs. per
yard, 100 miles at 65 lbs. per yard, and the remainder,
in detached lengths varying from 50 to 70 miles, with
rails varying from 60 lbs. to 85 lbs. per yard.
While the rails were thus being increased in weight,
the engines and carriages were also made heavier.
The first engine run upon the line, including its ten-
der, weighed '7 % tons; but engines of this power were
soon found to be insufficient for the traflic, and for
the increased speed which this new form of power
seemed to promise. As an increase of speed required
an increase of power, and an increased power neces-
sarily required an increased weight, engines were
formed of the augmenting weights of 10, 12, and 15
tons. For some years the engines were made of
gradually increasing weights, and at the present time
one Company has upwards of 36 engines, weighing,
with their tenders, about 40 tons each; and engines
have been constructed of the enormous weight, in-
cluding the tender, of 60 tons each.
So also with respect to the carriages: those first
- used on railways weighed from 3 to 3% tons; their
weight is now in some cases over 41%,,- tons. The goods-
waggons have also been increased in strength and
weight.
The increase in the traflic and in the speed, which
have led to the increased power of the railway, has
been far beyond the most sanguine expectations of
the first railway directors and engineers. In 1831
the average speed of the passenger-trains was 17
miles an hour : this was gradually increased until, in
18i8, it was 30 miles an hour; while the speed of
the fastest trains which, in 1831, was '24: miles an hour,
was in 1848, on the Liverpool and Manchester line,
40 miles an hour, and on the‘ Grand Junction and the'
Liverpool and Birmingham,- 50 miles an hour.
In 1837 the number of trains per day which arrived
at and departed from the Euston Square station of
the Birmingham line was 19 ; in 184.8 it was 414:. In
1831 the number of trains per day to and from the
Liverpool terminus of the Liverpool and Manchester
Railway was 26; in 1848 it was 90. - .
A corresponding increase also took place in the
weight of the trains. In 1831 the average weight of
a passenger-train, including the engine and tender, was
18 tons. In 184:8 it exceeded?" 5 tons. In 1831 the
average weight of a goods-train, including engine and
tender, was 52 tons; in 1M8 it varied from 160 to
1'7 6 tons. ‘ v

Attempts have been made to‘ ascertain the length
of time that arail will endure when subject :to the
usual traflic of a road. In this calculation accidents
have been ~excluded; such, for example, as the failure
of a rail at one of the joints 5 for as the metal for each
rail is first made into a faggot, and then drawn'out
between rollers, the welds or joints of the faggotted.
pieces are apt to give way. The flange of a wheel
will also in some cases come in contact with a ragged
portion of the flange of the rail and tear it up; so
that from these and other causes the rail seldom~
attains its natural age, or wears out in consequence of
the abrasion from its surface of portions of the metal
composing it by the passage of the vehicles. It‘
appears from an inquiry made under the direction of
the North Western Company, that rails laid down at
the average weight of 70 lbs. per yard, exposed to
a traffic equal to that which existed at the time of
the inquiry, would have a duration of 20 years, after
which the entire line must be relaid.1
In laying down the rails provision must be made
for conducting the engines and carriages from one
line to another, for ‘which purpose switches and turn—
tadles are introduced at particular points. Switches
are movable rails placed at the junction of two tracks,
and capable of being adjusted so as to guide the train
from the single track into either of the two tracks,:or
from either of the two into the single track. But
before describing switches we will notice a contrivance
for overcoming the inconvenience of a change of gage
at one particular spot, as, for example, where the
narrow gage already exists,‘ and it is desired to con-
nect it with the broad gage. The most economical
plan is to lay athird rail outside the narrow gage line,
at such a distance from it as will accommodate the
broad gage carriages. This‘ plan was adopted on that
part of the Birmingham and Gloucester Railway which
extends from Gloucester to Cheltenham. The Birming-
ham and Gloucester Railway is a narrow gage line,
and the Great Western Company wishing to extend
their ‘line from Gloucester to Cheltenham, put down a
third rail on the outside of the narrow
line. At a short distance from the
Cheltenham station of the Birming-
ham and Gloucester Railway they
quit that line, and run by a branch
of about a mile into‘ Cheltenham.
Fig. 1881 will explain the mode‘ of
arranging the rails at the point
where the two lines separate, so
that while the narrow gage trains
pass along the old track,‘ the broad
gage quit the same, and turn off to
the branch line without the attend- 9 i
ance of any one. AB, CD are the a U A
rails of the narrow gage line, B F, e H Fm 1881,
those of the broad gage, err being the continuation




of the-additional outer raiL The line of rail AF is''
cut through at n and at p, in order to allow the

(I) An account of this inquiry, together with that of a simi-
lar inquiry in Belgium, is given in Dr. Lardner’s “Railway
34
= Economy,” 1850.
558
ROADS AND RAILROADS.
flanges of the wheels of the narrow gage trains to
pass; and the rail on is also cut through at p, to
allow the wheels of the broad gage carriages to pass.
When, therefore, a narrow gage train approaches
the point E, the flanges of the wheels are kept close
to the rail AB by the opposite rail 0 I), and they
will evidently pass through the cut at n, the train
moving in its course along the old line. But when
a broad gage train arrives at the same point, the
wheels are drawn over towards the rail G H by
means of a clock or guard-mil, gr, which acts on the
inner side of the flanges of the wheels, by which
means they are prevented from passing through the
cut in the rail at E, and are made to move along the
line AF, e11. Where the rails terminate at lo, 9, and
r, the opening is enlarged in order that the flanges
of the wheel may enter without difficulty.
For crossing from one line of rails to another a very
Common plan is, to lay down a short intermediate line
with means for connecting
or disconnecting it with
either of the main lines.
These means are afforded
by the switch already re—
ferred to, and represented
in Fig. 1882, in which AB,
0 1), are portions of the rails
of the main line; ej”, g /1,
portions of the short inter-
mediate line: all these rails
are fixed except the two
rails f i, l: l, called the
tongues of the switch; these
move on centres at f and t,
their other ends are gradu-
ally brought to a point, a
small recess being cut in
the fixed lines at i and l,
into which they fit. These
tongues are connected to-
gether by a bar 6, which
keeps them at such a dis-
tance apart that when either of the tongues is in con-
tact with the rail near it, the other is sufliciently
removed from its rail to allow the flange of the car—
riage-wheels to pass between them. If it be desired
to cause the train moving in the direction of the
arrow to quit the main line and enter the branch,
the bar 6 must be moved to the position shown in the
left figure ; but if the train is to continue its journey
on the main line, the position shown in right-hand
figure must be adopted. The switches are usually
maintained in the position shown in the left figure,
by means of a self-acting weight; but if the train is
required to quit the line, a man must attend to move
the switches into the position shown in. the right
figure. Two guard-rails gr, gr, are required to pre-
vent the flanges of the wheels from striking against
the point ,at the intersection of the two lines.
Other methods of using switches are illustrated in
Fig. 1883. When the trafiic between two termini is
not expected to be great, it is often desirable for the


Fig. 1882.

sake of economy to lay down only a single line of
rails: but in such a case some coutrivance must be
made for allowing trains to pass each other. When
the traffic is about equal in each direction, the
passing-place may be arranged as in A n. The
angles in this figure are made more abrupt than is
desirable on a line of great traffic, where angles of
more than 2° or 2%0 should be avoided. A train
coming along the single line A, proceeds by the lower

l
/
33
Fig. 1883.
track to 18, while a train from B to a takes the upper
track. Switches such as those already described are
used at the points A and B, and being always passed
through in the same order they are made self-acting.
The arrangement 0 D can be used without any switch,
the rails being cut through at the proper points, (as
already explained in the case of Fig. 1881,) for the
reception of the flanges in changing the direction from
the single to the double line of rails. '13 F is a crossing
for occasional use, the switches being worked by hand
at the points s s.
One form of apparatus for moving the switches is
shown in Fig. 1884, in which 9‘ is the rod attached to
the rail, corresponding to l) I), Fig. 1882, and also
shown at s, Fig. 1883. This rod is hinged to a lever
L at 72. The lever moves on its centre at m, so that



ME I’ g i
/ W %%AT//fi//Wm
Fig. 1884.
when the lever is moved into or beyond the vertical,
the rail to which r is attached will evidently be made
to fall into the notch of the other rail. The weight w
is intended to keep the lever, and consequently the
switch, in the position in which it was left by the
pointsman. It is very important to attach a signal to
the post containing the lever apparatus for moving the
switches. The signal may consist of a coloured disk
of wood, or stretched canvass, so arranged that when its
broad surface is placed in the direction of the coming
train, the engine-man may know that the switches are
in the right position for passing; but if the edge of
the signal is towards him, he may then have an
opportunity of slackening his speed or stopping until
the proper adjustment has been made.
The turntable is a contrivance for moving a single
carriage at a time from one line of rails to another.
ROADS AND
RAILROAD S. '5 59
It consists of a circular platform of timber or iron,
supported on rollers and turning upon a centre with-
out much friction, even when loaded with a consider-
able weight. The best construction of turntable
adapted to six-wheeled carriages is illustrated in the
following figures. Fig. 1885 shows a quarter plan
of the top of the table and a quarter plan of the
moving apparatus and fixed framing forming the base
and easing of the table. Fig. 1887 is a cross section
of the moving apparatus, and Fig. 1886 a side view of
one of the latches by which the moving table is
secured in each of its positions. r r are solid rails of




Fig. 1887.
wrought-iron fixed on the lid so as to correspond
with the gage of the line, and forming 2 sets of rails
or tracks crossing the lid at right angles to each
other. The covering plates P 1?, which form the lid of
the table, are of cast-iron corrugated on the upper
surface, and resting in fillets on the cast-iron top
framing ff The lower framing, also of cast-iron, is
furnished with arms a a, a bearing rim 6 b, and a hollow
central boss .5‘ s. The upper framing is also perforated
in the centre at 00. The movable top framing is
supported by resting near the periphery on 8 cast-
iron conical rollers c c, which turn upon the bearing-
rim {2 b of the lower framing. It is also supported at
the centre by bolts passing through the rim of a strong
wrought-iron centre-pin p, turning in a gun-metal
step g, supported in a socket is, which is held in the
lower framing ss. The interior of the socket and of
the central hole in the top frame is truly bored to fit
the turned surface of the pin 12. The rollers c o are
held in their places by means of rods Z Z, screwed in
wrought-iron rings z', and passed through a light fram-
ing formed of a ring of flat iron 0, and of a continuous
bar e of angle iron. The bar and the ring being
bolted together, the ring 2' fits a shoulder formed on
the socket t. The bearing rings of the upper and
lower framings are accurately planed to fit the turned
surface of the conical rollers. The casing consists of
8 segmental pieces mm, bolted together through the
meeting flanches an, and bolted also to the ears was
cast in the lower framing. The latch L is fastened by
a pin to a small bracket bolted to the casing ; four of

these latches are thus fixed and are dropped into
notches n, Fig. 1886, for the purpose of retaining the
table in each of its positions. At 22 is a manhole for
giving access to the interior, for the purpose of oiling
the rollers, &c. An unyielding foundation must be
provided, or the cast—iron tables will be broken under
the heavy weights placed upon them. In some cases
a foundation is formed by constructing a well of
brick-work, on the rim of which and on a central
pier the table is fixed. In other cases the central pin
is much extended in length, and the periphery is sup-
ported by stout bars fixed in a jacket revolving on
the lower part of the long centre pin.
Turntables are useful for removing a single carriage
from one line to another, and for this purpose they
are often preferred to crossings and switches, because
they occupy so little space. Fig. 1888 will show the
method of using them. Supposing a carriage w is to
be transferred from the track A to the track 13, it is
rolled upon the turntable at T, and the catches u hich
hold the table being raised,
the table with the carriage
upon it is turned a quarter
round, into the position
shown by the dotted
figure. The carriage is
then rolled upon the turn-
table T’, which being in like
manner turned a quarter
round, the carriage is in
the proper position 20’ for
being moved to the track
13. By this arrangement
carriages may also be removed to a cross track, as
at o. The houses in which locomotive engines are
kept, are often made octagonal, with 8 tracks radiat-
ing from a large turntable in the centre.
The limits of our space will not allow of much fur-
ther detail respecting the permanent way. It should
be properly fenced in with some of the ordinary kinds
of fencing, or with stone walls in places where stone
is abundant. Near stations brick or stone walls should
be used, or the fence may consist of posts and battins.
The drainage of the permanent way must also be
carefully attended to. For this purpose gullets are
commonly cut across the ballasting for the purpose of
leading the surface water into the side ditches or
drains. Central longitudinal drains of rubble work, or
of perforated tiles, are also sometimes formed in the
cuttings and embankments: these drains communi-
cate by means of cross-drains from 10 to 25 yards
apart, and are formed much in the same manner as
the open side drains. Through the entire length
of the railway, there should be 41 parallel water-
courses, 2 on each side. The tops of the slopes
of cuttings- should be protected by a fence and a
mound, and outside these should be a field-drain for
the adjacent land. At the feet of the slopes there
should be drains for the water from the banks and
from the surface of the railway. Drains should also
be provided at the bases of embankments for carrying
off the water from the railway and from the surface of





Fig. 1888.
560
ROADS AND RAILROADS.
the banks, and parallel drains should be formed out-
side the fences. The surfaces of slopes are drained
by V-shaped channels, as already noticed.
The stations and the termini should be arranged
according as the passenger and goods traiiic is large
or small. On approaching the stations the two lines
are in some railways made to diverge from each other
so as to bring them close against the platforms, one_
of which serves as the departing place, and has the
booking-offices, &c., contiguous to it, the other being
the arrival platform, in the immediate vicinity of
which are the refreshment rooms, 860. In other rail-
ways the rails go straight through all the stations.
If the station be an intermediate one, both platforms
will be used as arrival and also as departure platforms.
At each terminus the space behind the 2 lines should
be wide enough for 3 or more spare lines of rails, to hold
carriages of all classes, horse-boxes, carriage-trucks,
&c. Access from the main lines to these spare lines
is obtained by switches, and by one, two, or more
rows of turnplates, one row being placed across each
of the extreme ends of the stations, and another inter-
mediate, so that first, second, and third-class carriages
may be introduced at any part of the train. The spare
lines are connected with the main line by means of
switches, the tongues of which admit of being wholly
removed, except when in actual use, in order to
prevent an arriving train from running against the
points.
The construction of the locomotive engines will be
given under STEAM. The railway carriages scarcely
require description. They are of large size, and the
bodies are made to project over the wheels. No
danger arises from this arrangement, because the
evenness of the line, the low build of the carriages,
and the great weight of the iron wheels, axles, and
framing, prevents them from overturning. The great
speed at which they are moved, and the shocks to
which they are subjected, require them to be strongly
built; and the fact that many of these ponderous
vehicles, heavily laden, are linked together, requires
the introduction of an elastic apparatus, which comes
into play both at starting and at stopping the train.
The traction must also be elastic, in order that the
engine may not have to overcome the inertia of the
whole train at once. For these purposes various
contrivances have been made, the most common of



Fig. 1889.
which are shown in Fig. 1889, which represents the
ground plan of a passenger-carriage, the body being

removed. The frame which is outside the wheels is
on lapped springs, which rest, by means of brass
bushes, or hearings, on the ends of the axles, which
are extended beyond the wheels, and are accurately
turned for the purpose. BB are buffers or disks of
wood or metal covered with cushions, attached to the
ends of long rods, which pass through the frame and
along the sides to the ends of the long springs s s,
which are so formed as to move towards each other
when pushed by the rods, but are prevented by stops
on the frame from moving in the opposite direction.
As the centre admits of sliding backwards and for-
wards, both springs are acted on by an impulse from
either end. As all the buffers in a train are of the
same width, and at the same height, they come in
contact when, in consequence of a sudden stoppage,
the carriages run closer together, and the jerk is thus
imparted to the springs s s, the elasticity of which
allows of sufficient motion to prevent any sensible
shock to the carriage or to the passengers. The
apparatus by which the carriage is drawn forward
consists of rods 9' 7', which pass through the frame at
ff, and are connected with the small springs ss,
which also act together, the centre of s pressing
against the cross-bar of the carriage-frame as an
abutment when the pull is in one direction, and
against the centre of the other spring when the pull
is in the other direction. The connexion between
the different carriages may be a jointed bar of iron,
which is disconnected by the removal of a pin; or by
apeeuliar kind of screw, which draws the carriages so
close that their buffers come in contact. Chains are
also sometimes used.
Atmospheric Railway—The idea of employing the
pressure of the atmosphere as a motive-power on
railways has excited considerable attention, and led
to many costly experiments. The atmospheric rail-
way appears to have failed as a commercial specula—
tion, but as some of its mechanical details are inge-
nious, it requires notice in this place.
We may suppose the crude idea of the application
of atmospheric pressure as a motive-power to be as
follows :—Suppose a large pipe to be laid down on a
road, a mile in length, and that at one end of this
pipe were placed an air—pump for withdrawing the
air, and at the opposite end a piston, working accua
rately in the pipe, with arope a mile in length attached
to the piston, at one extremity, and to a train of car-
riages at the other. On pumping out the air from
the pipe, the atmospheric pressure upon the piston
would drive it along the tube, and the carriages would
be drawn after it. But under this supposition, the
carriages at the commencement of the experiment are
a mile from one end of the tube, and 2 miles from the
other end. In order to get rid of the long rope, it
was desirable to arrange the apparatus in such a way
that the piston and the carriages might travel together,
much in the same way as the short tube, or pencil-
holder inside a pencil—ease travels with the outer tube
or ring, which admits of being slid backwards and
forwards by the fingers. For this purpose it was
proposed to employ pipes with side-openings for attach-
ROADS AND RAILROADS.
561
ing a connecting-rod to the piston and the carriages;
and it was supposed, ‘that on covering this slit or
opening with a rope, the air within the tube could be
sufficiently rarefied “for the required purpose. This
proved to be a failure, but Messrs. Clegg and Samuda
patented an arrangement which we are about to
describe.1 Their first experiments, on a large scale,
were tried on a portion of *the "West London Railway
at Wormwood Scrnbbs. series of cast-iron pipes,
9 inches in diameter, and'half a mile in length, were
laid down, and although the pipe and the rails were
not in good order, yet on a gradient of 1 in 115, and
with a surplus pressure on the piston of about 9 lbs. to
the square inch, a load of goods weighing several tens
was propelled at a rate exceeding 20 miles an hour,
and in some of the experiments a speed of 30 or 40
miles an hour was attained.
The success of these experiments led the Govern-
ment to advance a loan to the Dublin and Kingstown
Railway Company, to enable them to construct a line .
on the pneumatic principle from Kingstown to Dalkey,
a distance of about 1%,’; miles. The line was ready for
passenger-traffic at the end of 1843.
In this railway the vacuum-pipe was about 15 inches
in internal diameter; it was of cast-iron, and was laid
down, in the same way as the large water mains, be-
tween the two rails of the railway. After. the pipes
were cast, a cutter was passed through them in the
direction of their length; they were then raised to
the temperature of melting tallow, and a mop dipped
in that material was passed through them, and being
followed by a wooden piston, the inside became
coated with a thin surface of tallow, which soon ac-
quired great hardness. This was found to be an
excellent surface for the piston to travel against. On the
top of the tube was a narrow opening extending the
whole length, closed by a valve v v, Fig. 1890, so as
to render the tube air-tight. This valve was a con-






\ "-k - /
“WEB mm
W
an


Fig. 1890.
tinuous flap of leather, on the upper and under sides
of which plates of iron were riveted, the inner sur-
face of the lower plate formed to the curve of the
pipe, the upper plate and the leather being made a
little wider than the opening or slot, and extending
over it on each side. This continuous valve was
hinged on one side to a projecting rib, and the other
edge fell into a groove t containing a composition of
wax and tallow, which, when melted, scaled up the

(1) It is stated that Papin, more than a. century ago, suggested
this mode of travelling. In recent times schemes have been pro-
posed by Lewis, Vallance, Medhurst, and Pinkus. According to
Mr. Vignoles, it was Medhurst who, about the year 1812, first
suggested the right idea of connecting the body in the pipe or tube,
directly acted on by the atmospheric power, with acarriage moving
on the outside.
VOL II.

pipe, and made it sufficiently air-tight for the working.
A flap, called the went/w?‘ valve, w, protected the ap-
paratus from the weather. The piston contained
within the tube was furnished with a rod 14 or 15
feet in length, to which were attached rollers n,
Fig- 1891, for opening the air-tight valve behind the
piston as it advanced along the pipe. The piston was

Fly. 1891.
connected with the first carriage, or driving-car, by
means of a coulzfer c: to the driving—car was attached a
copper vessel, several feet in length, heated with coke,
for the purpose of melting the wax and tallow when
the valve had been pressed down by the apparatus.
The tractive power in the pneumatic railway depends,
as already stated, on the clg'fl'erence of pressure before
and behind the piston. The sectional area of a piston
15 inches in diameter is about 17 6 inches. If the
air in the tube in front of the piston be rarefied so
as to produce a pressure of 10 inches of mercury,
then the ordinary pressure of the air on the other side
of the piston, which on an average is equal to about
30 inches, will be 30-10, leaving a working pressure
of 20 inches. Now a pressure of 30 inches of mer-
cury is equal to about 15i-lbs. on the square inch [see
AIR]; that of 20 inc-hes is equal to 101bs., so that the
working pressure in this case is 176 X 10 =17601b's.
It will be understood, then, that the train of car-
riages moved on rails as in the ordinary railway; but
between the rails the tube with its enclosed piston
was situated; and that an air-pump worked by a
stationary steam-engine, exhausted the air in the tube
in front of the carriages. The speed of the train
would evidently be in proportion to the rapidity with
which the air could be pumped out. It was found
that an exhaustion of 15 inches could be produced
in about .9 minutes, and that a speed of 50 or 60
miles an hour could be produced.
The action of the apparatus will be better under-
stood with the assistance of Fig. 1892, in which the
rollers for opening the air-tight valve are shown.
The piston 12 is supposed to be travelling in the
direction of the arrow: as it advances, the two small
rollers rr lift up the air-tight valve, which, when the
coulter c has passed, is allowed gradually to fall into
the groove again by the corresponding rollers WT’,
and is firmly pressed down into its proper position
by the upper roller a. The long heater H follows,
0 o
562
ROADS AND RAILROADS.
melts the wax 2‘, Fig. 1890, and reseals the pipe : c is
the connecting arm or coulter, and w is a counter~
balance weight for the piston. The seat for the con-
ductor is shown between the carriage wheels, and in




Fig. 1s92. ,_
Fig. 1891 is also shown‘the roller R for opening the
weather valve w. . ‘ k
In the line which we have taken as an example of
the working of the atmospheric railway for a short
distance, the carriages were attached to the piston
at Kingstown, the air was pumped out by means of a
double-acting pump with 5% feet cylinders at Dalkey,
worked by a stationary engine : the piston soon began
to move, the driving-car or piston~carriage opened the
sealed valves, and as the car passed, these valves were
pressed into their proper channel by the apparatus
described, and the heater followed and sealed the
valves, and when the train had arrived at its terminus,
the valves along the line were in a fit state for the
passage of another train. The return journey was
performed by descending the incline (which had a
gradient of 1 in 115, and in some places was even
steeper) from Dalkey to Kingstown by the action of
gravitation only, and as the piston was not required
for the purpose, it was taken out of the tube and
placed outside.
In the year 184:5, a portion of the atmospheric
railway from London to Oroydon was opened for
traffic. This .line was constructed on the eastern
side‘of the locomotive line of the Brighton Company,
and -.to prevent it interfering with that line at the
point where it diverges from Oroydon, it was con-
ducted over that railway by a timber viaduct, to which
it rose on each side by a slope of 1 in 50. These slopes
were generally ascended without any difficulty, al-
though on some occasions .the power was not suiti-
cient' for the purpose. In the summer of 18416 the
iron tube, by exposure to the sun, frequently became
so hot as to melt the composition which sealed the
valve, so that the vacuum could not be maintained,
and. the line had to be worked by locomotives. Other
lines were constructed on the atmospheric principle,
but the difficulty of commanding a sufficient amount of
rarefaction for working purposes, gradually led to the
abandonment of the system. Several ingenious sug-
gestions were made to remedy the inconvenience.
One, by Mr. Hallette, was, to make the coulter a thin
flat bar, passing vertically through a slit in the upper
part of the atmospheric tube, and to keep this slit closed
everywhere, except where the coulter was passing, by
means of two continuous air-bags or hose placed in
a collapsed state in grooves in the top of the pipe,
and then inflated with air so as to press against each
other. This certainly is the most simple of all the
valves that have been proposed for the atmospheric
railway tube, and its action may be illustrated by

drawing a paper-knife between the closed lips. Other
plans have been proposed, among which may be men-
tioned a magneto-atmospheric railway. It is described
in the Mechanics’ Magazine for January, 184.16.
The Rape Railway—The great expense of loco-
motives and their enormous weight, have led to the
use of stationary engines, which have been employed
to draw the train by means of a rope. There is no
doubt that stationary engines are more economical
than locomotives, but the ditficulty is, to provide a
rope capable of withstanding the tractive force and
the friction. For steep inclined planes the rope is
used for drawing up the train. In some cases the
rope is endless, and is conducted along both tracks
by grooved pulleys, to keep it- oif the ground, and is
passed at each end round a wheel placed below the
level of the road, the upper one of which is turned by
the engine. The plan of working a railway by what
are called tail-ropes was adopted on the London and
Blackwall railway. A stationary engine was erected
at London and at Blackwall, each of which turned
a grooved wheel, to which a rope of nearly 6-;- miles,
or double that of the railway, was attached. A train
starting from London was arranged with the Black-
wall carriages foremost, and then those for the inter—
mediate stations in the order in which they are required
to stop. A signal being given, the Blackwall engine
commenced winding up the rope, by which the train
was drawn forward at the rate of 20 or 30 miles an hour.
On approaching the first station, the carriage intended
to stop there, which was by this arrangement made
the last of the train, was released from the rope by
opening a pair of pliers .which connected it thereto,
and applying a brake to check the acquired momen-
tum of the carriage. The rest of the train proceeded
without interruption, a carriage being dropped behind
on arriving at the stopping stations. The Blaekwall
engine, in addition to drawing the train, had also to
unwind the rope from the barrel of the London en-
gine, so as to prepare it for moving the train back
again when reloaded. In the return journey, the
various carriages left behind in the first transit were
attached to the rope, and were all moved towards Lon-
don at the same time, but, of course, they arrived at
London in different times according to the points at
which they were dropped. When they were all col-
lected together at London, they were in the proper
order for another journey. The same arrangements
as the above were applicable to the two tracks, each
track having a similar apparatus, and being worked
alternately in both directions. In working this line
it was found very difficult to keep the ropes in good
order, and the passage of the ropes over the sheaves
produced much noise. Wire ropes succeeded best,
but these were not satisfactory. At length the rope
system was abandoned, and the line was worked by
locomotives, which continue in use.
In concluding the important subject of railways,
whichwe have extended to the full .extent- of our
limits, we have regarded a railway as a great en-
gineering work, and have therefore‘ confined our details
chiefly to those of construction. Information respect-
ROCKE'IL-ROPE.
563
ing‘the general economy and managementr'of the line
must be sought elsewhere.l
ROCK- or ROOH-ALUM. See ALUM.
ROCK CRYSTAL. See QUARTZ—SILICA.
ROCK SALT. See SODIUM.
ROCKET, a cylindrical case of pasteboard or iron,
attached to one end of a light wooden rod; the case
contains a composition which on being fired causes
it and the rod‘to be projected through the air by a
force arising from the combustion. The use of
rockets is to communicate signals between parties
separated by distance or by darkness, and they have
been employed in trigonometrical surveys, and for
ascertaining the difference in longitude between two
places. Rockets are also used in warfare. In signal
rockets the upper part of the case, containing the
powder which produces the projectile force, has
united to it a conical case for the composition which
by its explosion produces the stars of light that form
the signal. Rockets of this kind may weigh from
from t-lb. to 2lbs. A 11b. rocket is 1%inch in
external diameter, the length of the cylindrical case
is 12% inches, and the length of the conical head 35-
inches. The rod is attached to the rocket on one
side near the base: its length is about 8 feet, and its
thickness about half the diameter of the rocket.
The cylinder is filled with a mealed composition
consisting of saltpetre in the proportion of dlbs.
(ton, sulphur 12 oz., and charcoal or mealed gun-
powder 2lbs; the composition for producing the
stars consisting of saltpetre 81bs., sulphur 2lbs.,
antimony 2 lbs, mealed power 802., isinglass 3 33:02.
The isinglass is dissolved in 1 quart of vinegar, after
which 1 pint of spirit of wine is added, and the mealed
composition is mixed with the liquid into a stiff paste.
The composition for burning _is rammed into the
rocket-case, but a conical space is left along the axis
for access of air to facilitate the combustion; and at
the alto/re or neck of the rocket, where the rod is
attached, are apertures, by one of which the rocket is
fired. The use of these holes is to prevent the case
from bursting, the flame escaping by them into the
atmosphere; and the pressure of the gaseous matter
suddenly liberated against the opposite extremity
impels the rocket forwards or upwards, just as a gun
recoils on being fired. In the case of a gun, however,

(1) Dr. Lardner’s “ Railway Economy,” already referred to, is
full of valuable information, presented in a. clear and useful
manner, respecting the management and statistics of railways.
With respect to the history and details of construction up to the
year 1838, we must refer to Wood’s “ Practical Treatise on Rail-
roads,” 850. 3d edition, and to the article “ Railway ” in Hebert’s
Engineers’ and Mechanics’ Encyclopadia. This article is beyond
200 pages in length, and is abundantly illustrated. With respect
to construction, a very valuable work has been published by Mr.
Weale, entitled “ The Practical Railway Engineer: examples of
the mechanical and engineering operations and structures com-
bined in the making of a. railway.” Illustrated by 50 large steel
plates, containing numerous examples. Written for the Royal
Engineers by G. Drysdale Dempsey, C. E. 4to., London, 1847. We
have to express our thanks to Mr. Weale for his liberal permission
to make use of this work. In Mr. Whishaw’s “ Railways of Great
Britain,” will be found a notice of the chief features of most of our
lines, and the engineers of some of the principal lines have them-
selves published detailed illustrated descriptions of some of the
works executed by them.

the recoil is instantaneous on account of the extremely
rapid combustion of the gunpowder; but the rocket
composition is so compounded as to produce a com-
paratively slow combustion, and so long as the com-
position continues to burn the impelling force is
maintained. The use of the rod is to guide and
steady the flight of the rocket. Rockets of from 1 to
2 inches in diameter have been known to ascend
vertically to the height of about 500 yards; and
those from 2 to 3 inches diameter, 1,200 yards. The
times of ascent vary from 7 to 10 seconds, and the
rocket has been seen at distances varying from 35 to
40 miles. '
ROLL or ROLLER, a cylinder of iron, wood,
paper, &c., used in the‘construction of machines and
in several Works and manufactures; but sometimes
under other names. For example, the weaver in pre-'
paring his loom winds the threads or yarns on a large
roll called a beam. [See WEAVINQ] In the manu-
facture of plate glass a thick cylinder of cast brass,
called a running roll, is used for spreading the glass‘
over the casting table. [See GLASS, Sec. viii] Rolls
form an essential part of the machinery used in
CALENDERING. Copper-plate and lithographic print-
ing is performed at a roll-press. [See PRINTING, Sec.
viii] Friction rolls are two parallel circular plates of
brass, about 1;‘; inch thick. Four or more solid brass
cylinders are placed at equal distances round these
plates, and work upon their own axes between them
at right angles. Thus any pin working through these
plates and brass must touch the rolling surfaces of
the solid brass cylinders, by which the friction is
greatly diminished. Spherical rolls are also used.
See Burner, Sec. vi. Corinne, &c.
ROLLING MILL. See InoN, Fig. 1240.
ROOD, a quantity of land equal to the fourth part
of an acre, and containing 410 square perches or poles.
ROOF. See Oxurnn'rnr.
ROPE, an assemblage of several twists or strings
of hemp, twisted together by means of a wheel so as
to form a flexible and tenacious cord or band. The
term is usually applied to all cordage above 1 inch in
circumference made of hemp spun into yarns or
threads, of a certain length; a number of these yarns
or threads, according to the size of the rope, are twisted‘
together into astmad. Three of these strands twisted
or laid together is called a lzawser-Zaz'rl rwe, and 9 of
them a cable-laid rope. When the rope is made very
thick it is called a cable, and when very small a cowl.
Rope-making is an art which all nations seem to
have practised from the earliest times. Various kinds
of fibre have been used for the purpose, such as hemp
and flax, tough grass, the husk of the coconut, the
fibres of the wild banana, &c., and animal substances
have also been used, such as strips of oxhide, horse
hair and wool, and in our own day metallic wires have
been twisted and plaited into cords and ropes of great
strength and of various sizes.
Thongs of leather were used in the rigging of ships
during many ages ;- and at the present time in some
parts of the world ropes of considerable length and
strength are formed by twisting thongs of leather;
0 o 2
"564:
RCPE.
The ancient Romans are said to have made ropes by
the twisting of vegetable fibres long before the time
of Caesar; and after the invasion of Britain by that
people, they are said to have used our native rushes
or jwzcz' for forming ropes. Some writers suppose
this to be the origin of the term jun/r applied to old
cables and worn-out ropes.
The superiority of the fibres of hemp to those of
most other plants has caused them to be chiefly used
in the manufacture of cables, ropes, cords, canvas,
and sail-cloth. The cultivation, retting, &c., of hemp
is described under HEMP. In forming a rope, as
already noticed, the fibres are first spun into yarns,
the yarns into strands, the strands into a rope, and
the ropes into a cable. The shortness of the hempen
fibres (about 3% feet being the average length,) re-
quires this complex arrangement. If they were long
enough to form a rope the most advantageous method
of using them would be to lay the fibres side by side,
and to secure them at the two ends. Each fibre
would then bear its own share of the strain, and the
strength of the bundle would be that of the sum of
the strengths of the separate fibres. As along rope
could not be formed in this way, the ends of the
fibres are secured by twist-ing so as to produce suifi-
cient compression to prevent the fibres from sliding
upon each other when a strain is applied; but in
attaining this amount of compression by means of
twist, the strength of the fibres is greatly deteriorated;
this very compression acts as a constant weight on
the strength of the fibre, and must be deducted there-
from before the available strength can be applied.
Réaumur found that a small well-made hempen cord
broke in different places with 58, 63, 67, and 7 2 lbs,
its mean breaking weight being 65 lbs. 5 while the'3
strands of which it was composed bore 29:1,, 33%, and
35 lbs. respectively; so that the united absolute
strength of the strands was 981bs., although the
average real strength of the rope was only 65 lbs., thus
showing a loss of strength from twisting equal to
33 lbs. Béaumur’s experiments were made in 1711.
The more recent experiments by Sir Charles Knowles
give a nearly equal loss of strength by twisting. He
found that a white rope of 3% inches in circumference
broke on an average of several trials with 41,552 lbs.;
while the aggregate strength of its yarns, 72 in
number, was 6,480 lbs. (each yarn bearing about 90 lbs.) ;
thus the loss was 1,928 lbs. or about 30 per cent. '
The strength of ropes is sometimes calculated by
the following rule :-——Multiply the circumference of
the rope in inches by itself, and the fifth part of the
product will express the number of tons the rope will
carry. Thus, if a rope be 6 inches in circumference,
6 X 6 == 36, the fifth of which is 7-51.
The weakening effect produced by twisting varies
considerably among the fibres of the same rope ac—
cording to their distance from the centre or heart of
the bundlef If a certain amount of twist be given to
a bundle of fibres, the outer fibres, occupying more
space than the inner ones, will be strained more, and
_will act with, less useful efiect than the inner fibres,
which will have to bear the greater part of the strain

while the rope is being used. It will therefore be
evident that if the fibres of hemp were twisted at
once into a thick rope the outer fibres would be so
much strained as to be of little or no use in con-
tributing to the strength of the rope; but by first
twisting the hemp into slender yarns, and a number
of yarns into strands, and 3 of these into a rope, the
strain is more equalized, and the important properties
of length and strength are secured without too great
a sacrifice of the strength of the individual fibres.
There is also another reason why a‘rope could not be
at once formed by twisting a bundle of fibres together.
Such a rope when left to itself would immediately
begin to untwist. This tendency to untwist is
counteracted by twisting the fibres together in small
portions and then combining them in such a way that
the tendency to untwist in one part shall counteract
that tendency in another.
Duhamel has endeavoured to ascertain the amount
of twist that would produce the most useful effect.
He made some ropes in which only ;}-th the length of
the yarns was absorbed in twisting instead of the
usual proportion of —_t;d. These ropes when used in
shipping were found to be lighter, thinner and more
pliant than those in ordinary use. Ropes made of
the same hemp and the same weight per fathom, but
twisted respectively to TE-ds, i-ths, and 4the, of their
component yarns, supported the following weights in
two experiments :-
% ds. 4t,0981bs. ét,25(llbs.
-}ths. 41,850 6,753
%ths. 6,205 7,397
The result of these experiments led Duhamel to
make ropes without twist, by placing the yarns
together and wrapping them round to keep them
together. ’The rope had great strength, but not
much durability on account of the outer covering soon
wearing away or opening at bendings, and thus
admitting water, occasioning the yarns to rot. These
salcages or skeins of rope yarns are, however, used
for the tackle of great guns, and for some other pur-
poses where great strength and pliancy are required.
Preparation cf the yarn. Before spinning the hemp
into yarn it is heckled or hackled for the purpose of
separating and straightening the fibres. The heckle
is formed of a number of straight steel prongs set in
a board with the points upwards : they are of various
sizes; the smaller heckles strip the hemp of its short
fibres or tow, when the hemp is said to be cropped,
and is used for fine work, or for spinning below the
usual grist‘, as it is called, the usual grist being a.
rope 3 inches in circumference, with 20 yarns in each
strand.
In the process of heckling, a quantity of hemp
sufficient for spinning into one yarn 160 fathoms
long is first weighed out, and the heekler, holding
the fibres at one end, throws the bundle loosely over
the points, and pulls it gently towards himi' _a num-
ber of fibres is retained in the heckle, and by repeating
the process they are all retained. ' He then lifts up
the whole bundle, and passes it again through the
ROPE. .
565
heckle, the operation being assisted by the application
of a small quantity of whale-oil to the points. The
fibres, thus separated, and made tolerably parallel, are
tied up into a bundle, Fig. 1896, called a tow of hemp,
weighing about 3%lbs. Heckling greatly improves


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Fig.1893. HECKLING IIEMP. '
the appearance of the hemp, converting the hard
knotted mass, as shown in Figs. 1891, 1895, into
a loose silky skein, Fig. 1896.


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Fig. 18%.
Spinning—The fibres are spun into yarn in a long
rope—walk of 600 or 1,209 feet, one end of which is
called the head, or jbre-eml, and the other the foot‘, or
tack-end. At one end is a spinning-machine, Fi".
1897, consisting of 2' upright posts with a wheel be—
tween them, the band of which passes over several
rollers or wheels, Fig. 1897, turning on pivots in brass
holes, the pivots projecting and terminating in small
hooks, so that by turning the wheel the hooks are
made to revolve rapidity. Posts are arranged at
equal distances 0n- caeh side the walk, Fig. 1899,
and between every pair of posts a rafter is extended
across ; hooks are driven into this rafter for the pur-
pose of supporting the yarns as they are spun. '
The number of whirls in the spinning-machine
(generally about 12) determines the number of spin-
, putting forward more if the supply is defective.

ners that can work together. Each spinner wraps
round his body a bundle of hemp sufficient for the
spinning of 1 thread of yarn, taking care that the big/M
or double of the .
fibres is in front,the
two ends passing
behind his back.
He draws out from
the face of the
bundle as many
fibres as the size of
the yarn requires,
and, twisting them
between his fin-
gers, attaches the
bight to one of the
whirl-hooks, while
lhe wheel, being
turned by an as-
sistant, throws
twist or turn into
the fibres. The
s inner holds in his ,
riPght-hand a piece Fm 1898' .
of thick woollen cloth, with one end hanging over the
forefinger; with this cloth he grasps the fibres as
they are drawn out, and presses them firmly between
his two middle fingers, walking backwards all the
time from the head to the foot of the walk, occasion—
ally making a signal with his left-hand to the wheel-
man to turn fast or slow as may be required. He
regulates the supply of fibres with his left-hand so as


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.<,--_,___ _v..
Fig. 1899. SPINNING non: YARNS.
to make the yarn of equal size, drawing back some i f
they enter his right-hand in too great a number, and
He
does not allow the ends of the fibres to come near
together, but distributes them in a kind of flat skein,
so that the yarns may have a similar strength through-
out. The thickness of the yarn depends on the
quantity of hemp which passes through the spinner’s
hands in a given time, and on the rapidity with which
the hook is made to turn. The spinner walks back-
wards at the rate of about 2 miles an hour, and as the
yarn increases in length, he throws it over the hooks
566
ROPE.
on the under side of the rafters, which are placed 5
fathoms apart. When the spinner has got to the
lower end of-the walk, and his length of yarn is sufli-
cient, it is detached from the wheel and fastened to a
reel, the spinner holding the end of his yarn, for if
let go it would untwist : as the reeler turns the reel
the spinner walks slowly in, keeping the yarn equally
tight all‘the way.
The spinner is paid’ 76. for spinning 6 threads or
yarns. This is called one guarter’s work. A good
workman will in one‘ day ‘spin 8 quarters, or 4:8 yarns,
each yarn 160 fathoms in length 3 and as the spinner
has to traverse the whole length of the walk twice for
eve'ryiyarn, once in spinning it out, and back again in
reelingit in, he has. thus to walk nearly 18 miles in
the ‘course of one day’s work.
Rope yarns are commonly from {32th torath er over
73th inch in diameter; 160 fathoms of white, or un-
tarred yarn, weigh from 2% to elbs.
Whena number of spinners are set-072 at the same
wheel, each fastens his thread to a whirl, and they
all proceed together down the walk; each man throw-
ing his yarn on one of the hooks of each rail as he
passes it. When they arrive at the foot, they join
the ends of every pair of yarns and hang them over
the post; and in order to be able to separate them,
a piece of twine is tied by the middle to the first pair
a little in advance of the post; the second pair is
then put over the post, and a string is tied over them,
and in this way every pair is tied in. This is called
m’tzllz'rzg. The spinners now set-0n at the foot or baa/a-
erzdwkeel, and spin up the walk. The forward wheel—
man having unhooked the yarns from the whirls of
his .wheel,--and hung them over the posts, and tied
them'in' pairs at the back-end, proceeds down the walk
p collecting the yarns from the hooks.
Rope-yarns are now in some places spun by ma-
chinery, as will be noticed further on; but we may
here mention that, by the improved apparatus of Mr.
Lang of Greenock, the hemp is completely heckled,
and each fibre is laid at full length in the yarn instead
of being doubled as in hand-spinning. These machine-
spun yarns have a strength of 55 percent. over- hand-
‘spun yarns of equal grist.
If the cordage is to be ‘tarred, the process of jarring
f/w yarns-is now introduced. Tarred- cordage‘i‘s con-
siderably weaker than u‘i'itarred, but it. is better calcu-
lated to resist the wet. It loses its strength gradually
in cold countries, and rapidly in hot climates. Ac-
cording to Duhamel,‘ untarred ropes sustained a
greater weight by nearly 30 per cent. than tarred
ropes; and he states that white cordage, in constant
use, is one~third more durable than tarred, that it retains
its force much longer when kept in store, and resists
the action of the weather one-fourth longer. Cordage,
when only tarred on the surface, is said to be stronger
than when tarred throughout. Messrs. Chapman, of
Newcastle, have stated that the rapid decay of tarred
cordage is due to the presence of the mucilage and
of the acid of the tar, which they propose to remove

(1) ‘f'Traité de la fabyiquej des manoeuvres pour les vaisseaux;
on Part de la c'orderie perfectionné.” 41:0. Paris, 1747.

by boiling the tar with water and concentrating the
washed tar by heat until it becomes pitchy, restoring
its plasticity before use by the admixture of tallow
or oils.
Preparatory to tarring, the yarns are warped
into a farm! ,- that is, they are unwound from the reel
or roller, and stretched straight and parallel, when 300
or 400 yarns are assembled in a large group or Mal,
about 100 yards long.- This haul is dipped into tar
heated to about 212° in a'copper or tar-kettle, and is
then dragged through-a hole, called a grip, or gage,
or sliding-flapper, which presses the tar'into the yarn,
and removes the superfluous portion. The tar must
not be too hot, or‘th’e' yarns will be charred; nor too
cold, or they will be black; they ought to be of a
bright brown colour}? The ‘proper temperature is
judged of by the closing in of a scum over the surface
of the tar. -
The yarns either tarre'd or. untarred‘ are next
twisted or laid int'o strands, the twist of the strand
being in an opposite direction to that of the yarns,
1n order to counteract the tendency of the separate
yarns to untwist, and that the yarns in their turn
may counteract the tendency of the strand to untwist.
The laying walk may be under the same roof as the
spinning walk. It is provided with tackle-boards
and wheels for twisting the strands, and stakes and
stake—heads for
supportingthem.
Thetackle-board,
Fig. 1900, for
twisting large -\ “ ._ strands is fixed; \\ ‘3gp i
at the head off" \ “ ' \ "'2' ,
the walk; it con- 7 I.
sists of strong '
upright posts “4' I "
supporting a plank pierced
with holes which correspond to the number of strands,
generally three, of which each rope consists. Winches




Fig. 1900.
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._ l‘r ‘I fiiii’lit‘ l1
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or foreloc/b hooks work through these holes. One of
the smaller wheels for laying the smaller strands is
shown in Fig; 1902; it is supported 011 a'strong'post
at-the head of the walk: the axes of the pinions are
‘prolonged into hooks, and the driving wheel is
worked- by a winch. The strands are supported by
beams or stake-heads placed at intervals along the
- walk; each stake-head, Fig.1903, contains a number
ROPE.
567
of upright pins, between which the strands are placed.
The yarns as they are run out for laying are first
~ secured to posts at the
head and foot of the
1 walk, and as they become


Fig.1902. Fig. 1903.
shortened by being twisted into strands they are
afterwards attached to movable sledges, Fig. 1905,
situated at the foot of the walk. The upper part of




m ‘than 5%


u..,_
Fig. 1904.
the sledge, called the breast-board, corresponds to the
tackle-board, Fig. 1900. The sledge is loaded with
press-barrels, i.e. old tar-barrels filled with clay, for
keeping it steady, and iron weights are also used for
the purpose‘:
Supposing now that the yarn is properly warped
for laying into strands it is run out along the bearers
of the laying walk, and the number of yarns required
for the rope is counted out, and divided into three
separate portions, each portion being placed in one
of the divisions of the bearers, and hung upon the
hooks of the tackle-board and sledge. The sledge is
pulled backwards to stretch the yarns tight, and the
press barrels are put on. The yarns are now examined
to see that they are of equal length and properly
‘I



\Ill'T‘
wvv w

Fig. 1905.
stretched; the hooks at each _end are now heaved
round in a contrary direction to the twist of the yarn,
and in this way the three bundles of yarn are formed
into 3 strands. By the consequent shortening of the
yarns the sledge is drawn forward some way up the
walk. When the strand is full band, or .has enough A

ILCH'CZ in it, as it is termed, the twisting is discontinued 5
the sledge is moved forward to- slacken the strands,
and to allow of their being taken off the hooks.
The three strands thus formed are laid or twisted
together into a rope; for which purpose they‘ are
attached to the middle hook of the tackle-board, and
then placed in the grooves of a conical block of wood,
Fig. 1907, called a top, through which passes a pin
for the handles or woolclers as they are called. A
piece of soft rope called a tail is attached to each
woolder by its bight in the middle, while the ends are
used to secure the rope in laying the strands. Tops
of various sizes are used, '
and when a top is of very
large size it is supported on
a sledge. Now the 3 strands
being attached to a hook of
the breast—board, and then
continued along the grooves
of the top as in Fig. 1909,
the top is‘forced back as
near the hook of the sledge
as possible, and the men at the head again turn their
hooks in the same direction as before. As soon as
the sledge begins to move forward, the men diminish


Fig. 190?.


Fig. 1908. Fig. 1909.
the load on the sledge, and turn the hook in a direction
contrary to the former, by which means the top is forced
forward; the 3 strands closing behind it as in Fig. 1908
form the rope. The reason for turning the single hook
containing the ends of the three strands in a con-
trary direction to the three hooks to which the other
extremities of the strands are attached, is to re-
gulate the progress of the twists of the strands
found their common axis, that the three strands may
receive separately at- their opposite ends just as much
twist as is taken out of them in consequence of their
being twisted the contrary way. in being laid to—
gether. When the top is some way‘ ‘off from the
sledge the tails are wrapped round the" rope, and
they by their friction prevent theftop from. moving
by jerks and also enable the ropef'fo close'better; In
this way a- rope is formed by“ twisting 31-‘s1tr1ai1ds
together. It will be seen that theistrandl's. unite into
a rope on one side of the top, and‘ are kept separate
on the other side, and that as the ropei'iis formed the
top is gradually driven forwards. ' The motion of the
top requires to be regulated so as to ensure equal
hardness in the rope: the topm'an, therefore, before
putting in the top, makes a mark aci'o'ss'the strands
of every beam: if, when the top'reaches a beam the
mark be above the bearer, the topman knows that the
turning at the foretop has been too fast ; if the mark be
below, he knows that the turning has been too slow.
In laying a very thick rope, the men may not be
able to turn the hook of the sledge to which the
strands are attached; but they are assisted by other
568
HOPE.
men, who apply woolders 'at' intervals between the
sledge and the top: the strap of each woolder is
wrapped round the rope, and the pin is used as a lever
to heave round the twist. The men at the'wool'ders
keep time in heaving with the men at the hook of '
the sledge; and in the case of heavy ropes the top
sledge is used to support the rope.
In laying the strands it is necessary to vary the
pressure at different parts of the process, and also the
angle at which yarns take their position in the strands;
the angle which the strands assume in forming a
cable also requires attention. In making a cable of
100 fathoms, for example, the length of the strands
should be 152‘ fathoms and should be laid at an angle
of > 27°; hard is given until each strand is shortened
the length of 10 fathoms, when the angle must be
37'". In making the strands the sledge travels 241
fathoms, and the angle then made should be 32°. In
laying the cable, the length of the strands thus formed
amounts to 118 fathoms, and the angle when hard
should be 40°. The length of the cable when finished
is generally 101 fathoms; the strands entering with
an angle of 35° while laying, and finishing at one
of 38°. .
With regard to the press-weights on the sledge:
those for the strands of a 12-inch cable begin at 60cwt.,
and when the length of 5 fathoms is attained, 10 cwt.
is subtracted, and at 7% fathoms another 10 cwt. is
removed; so that the press, when the strand is hard,
is 4-0 cwt. : but if it lays wellanother 10 cwt. is re-
moved for the remaining distance. In laying the
cable, the press begins at 160 cwt.:z this is reduced
10 cwt. at 1%— fathom; another 10 cwt. is taken off
at 2 fathoms, and when the cable is observed to lay
well, another 10 cwt. is removed, leaving a press of
130 cwt. for the rest of the cable.
The twisting of three strands together in ‘the man—
ner described forms what is called a lzazeser-Zaz'd rope:
' ‘this is called the first‘ lay.
' 7 1‘ r " The second Zag/ is ‘performed
with four‘ strands, producing
what is called a s/zroucl
lzawser-Zaz'd rope. The 4h
strands are laid in the same
way as the 3, and under the
same conditions; but in
order to render the rope
solid, a core-piece, consisting
of a few‘yarns, is run through
the centre. The z‘izz'rcl lay,
-or cradle-laid rope, consists
of 3 hawser-laid ropes, each
formed of 3 large strands,
*twiste‘d or laid together into
one gigantic rope or cable.
This, however, is now seldom
made, the chain-cable having
taken its place [see CHAIN-
oABLE]; but as cable-laid
ropes are very hard and compact, ropes of no very
great size are inade in this way, if intended to resist
the, action of water.

I ‘my. .1910.

Where great pliability is required, ropes are formed
by plaz'éz'rzg instead of twisting; as for clock-lines,
sash-lines, .and generally where ropes have to pass
over small pullies.
Flat ropes, used for mining purposes, are formed
of two or more small ropes placed side by side and
united by. sewing, lapping, or intertwining with thread
or» smaller ropes. Flat ropes are also formed by simi-
larly uniting a number of strands of shroud-laid rope.
In either case the component ropes or strands must
be alternately of a right-hand and aleft-hand twist, or
the rope would not remain at rest.
The weight of cordage may be calculated by the
following rules :—
For shroud or hawser-laid rope, multiply the cir-
cumference in inches by itself; then multiply the
product by the length of the rope in fathoms, and
divide by $20, the product will be the weight in cwts.
For cable-laid cordage, multiply its circumference
in inches by itself, and divide by 41. The product will
be the weight in cwts. of a cable 120 fathoms long;
from which the weight of any other length may be
deducted.
ROPE-MAKING BY MAcHInnnr—About the year
1792 a rope-making machine, named a eordelz'er, was
invented by the Rev. E. Cartwright, which does not
appear to have attracted much notice until 1805,
when it was partly incorporated into some very beau-
tiful rope-making machinery invented by Capt. Joseph
Huddart, which we are about to describe.1 This
machinery, in its most complete state, was introduced
into the Royal Dock-yard at Chatham for the purpose
of supplying the navy with ropes and the smaller
cables, the large cables, which were formerly made at
Deptford, having been superseded, as already noticed,
by the introduction of chain-cables. By means of
Captain Huddart’s machinery the hemp is cleaned
and combed, and divested of its loose splinters; the
fibres are disposed in a parallel and uniform direction,
and then spun into yarn with an equal degree of twist
and tension: the yarns are then ‘tarred, registered,
and twisted into one uniform strand; these strands
are twisted into ropes and cables by contrivances
which maintain one continued strain ‘in every stage,
combined with a uniform tension.
The methods of forming the fibres into yarn are
similar to those described under FLAX. The lzee/rlz'rzg,
or ‘g/z'ZZz'rzg-mae/zz'rze, consists of a number of pointed
wires, called gills or freckle-teeth, fixed in an erect
position to an endless chain moving at a uniform rate.
The rough hemp is spread out by a looynpon a feed-
ing—trough into a loose bed, by the motion of which
it advances in a broad‘uniform sheet towards the two
rollers, which seize it, while the heckle pins, conti-
nually moving forward, comb and disentangle the
fibres, and make them parallel. The stream of hemp
being gradually ‘drawn forward, at length escapes
from the heckles, and is received between drawing-

(1) We are indebted for this description-to a paper by Mr. John
Miers, contained in the fifth volume, of “ Papers on subjects con~
nected with the duties of the'Corps of RQyaLEngineers.” ‘Ito.
London, 1343. r- i
ROPE.
1569
rollers, revolving at different speeds, whereby the
fibres are drawn out and compressed into a broad
thin riband. It is next gathered bya guide into a
narrower space, and compressed between other small
rollers, which deliver the sliver thus prepared into a
can. In a second machine two of these slivers are
doubled into one, and, in a third machine, the doubled
sliver is still further drawn out into a single and more
uniform sliver.
The sliver thus prepared is received into a deliver-
ing can, and passed to another machine, called the
compressor. This machine consists essentially 'of a
solid metallic piston, sliding upon a square horizontal
bar, with considerable resistance, by means of a
spring. The filling-can, which is open at both ends,
is slid over this piston, and held in its place between
two fixed ends or caps, one of which is conical in
shape, and one end of the piston, being also conical,
corresponds to the inner surface of this cap. The
end of the sliver is passed through a slit in this cap,
and is then tied to the piston; by the revolution of
the bar and can the sliver is then made to wind
itself upon the bar, while at the same time it is
compressed between the cone and the piston. In
this way, by the accumulation of the yarn, the piston
is gradually pushed forward; and when the can is
filled with compressed sliver, the piston acts upon a
rod which throws a forked lever aside, whereby the
driving strap, which causes the winding bar and can
to rotate, is shifted to the loose rigger, and the ma—
chine stops of itself. A boy then removes the full
can, and places an empty one, and sets the machine
at work as before.
The compressed sliver next passes through the
spinning machinery, which of course does not differ
in principle from the machines employed in spinning
cotton slivers. Each spinning frame comprises 12
spindles, or spinning tubes, and 3 winding drums.
The spindles are set in motion by a main shaft, upon
which are fixed, at equal distances, 12 pulleys, in
which endless cords work, that pass also in corre-
sponding pulleys attached near the base of the 12
vertical spindles. Each spindle is accompanied by
a can of compressed sliver, and the can is made to
revolve with a certain speed, in order to give a pre-
paratory degree of torsion to the sliver. It receives
a further degree of twist by passing through the hollow
tube, the point of which is furnished with ‘clipping
jaws, which grasp the thread; and while it is being
twisted with great velocity, it is subjected to a con-
siderable degree oftension and compression by being
passed over and under 4. pulleys in succession. From
these pulleys the twisted sliver, now called ‘yarn,
passes to 1 of the 3 winding drums. Each of these
drums receives 45 yarns from as many spinning tubes,
and the yarns are prevented from getting entangled
with each other by being passed separately through
corresponding holes ‘in the register plate of a regu-
lating bar. In order that the yarns may be equally
wound upon all parts of the drum, they are made to
move in succession to the right or left, while being
wound from one end of the drum to the other, and

back again. This is accomplished by giving to the
regulating bar a right and left horizontal motion,
through a space equal to the length of each winding
drum.
From the drums the yarns pass to the winding
machine, the object of which is two-fold; first, to
separate the 4! yarns previously coiled together upon
each drum, and then to wind them a second time upon
distinct bobbins or reels; and, secondly, by the same
operation to reverse the lay of the yarns, so that, in
going through the subsequent process, each may fol-
low the same course in which it was spun. If this
precaution were not adopted, the ends of the fibres
would be drawn out, and the strands would be rough
and unsightly.
One of the most important of Captain Huddart’s
inventions is the register, the object of which is to
keep all the yarns separate from each other before
being twisted into strands. For this purpose they
are wound upon reels turning freely upon spindles,
in such a manner that each is allowed to contribute
the exact length of yarn, and no more, in the uni-
form twist required in making a strand. The yarns '
being so arranged, the end of each is passed through
what is called a register plate. This is a metal plate,
of a somewhat hemispherical form, pierced with as
many holes as there are yarns, which holes are
arranged in concentric circles, care being taken so
to apportion the number of yarns in each circle that
they dispose themselves in a compact form, with as
few vacancies as possible, round one common central
yarn. The distance, or diameter of each concentric
circle around the adjoining one in the register plate,
is such as to allow the several series of yarns to
arrange themselves at a determined angle, in order to
give them a proper position to enter into the general
twist now about to be given to the strand; this done,
the body of yarns united for the purpose is received
into a cylindrical tube, wherein they are made to
undergo a certain degree of torsion, by which at the
same time the whole is compressed into a compact
body: by this means the strand has a truly cylindri-
cal figure. Lastly, a certain amount of llarcl, or greater
degree of twist, is given to the strand, thereby in-
creasing the angle of the outside series, with the
view of compensating for the stretching ,of the yarns
and the compression of the strand. ,
Another improvement is, the adaptation of the
registering apparatus at a short distance from the
tube, and the winding of the strand so formed upon
a drum, subjecting it, in the interim, to a considerable
tension,-—a contrivance that ensures one common
uniformity of twist and diameter from one end of the
strand to the other, which could never be attained to
the same extent while the strands were made on the
ordinary rope-grounds, where they ‘remained extended
a length of nearly 1,000 feet, offering, from several
causes, a variable degree of elasticity, and an uncertain
amount of tension in difierent parts of the strand.
Captain Huddart further considered that the body
of yarns of which a rope is constituted can never be
brought together in a cold state without leaving con-
570
ROPE.
siderable vacancies, into which water must enter
while the rope is exposed to the weather, and engen-
der decay from fermentation caused by the included
moisture. This led to the invention of the warm
register, in which the yarns, being immersed in heated
tar, undergo the requisite amount of compression and
torsion while still warm. -
We now proceed to describe these inventions in
detail. We have traced the yarn up to that stage
in which it may at once be formed into strands; or
if intended to be tarred,‘ the process just alluded to—
the warm register—now comes into operation. The
tarring-house is separated from the other buildings
by a second partition, in order to guard against acci-
dents from fire. In the centre of the apartment is a
fire-place for heating the tar, protected by an arched

Fig. 1911.
convex circular plate ‘'1, which is pierced inlike manner
with round holes, through which the yarns are seve-
rally passed, all converging thence into one common
point, through the register plate 7', in which is a cylin-
drical tube of metal, fixed by its collar to a framework.
All the yarns thus brought together within this tube
here undergo a preparatory amount of twist and
pressure, and the strand s thus formed is conveyed
to the register mac/zine, in the adjoining apart-
ment, in order to undergo further twisting and
compression. The temperature of the tar is kept
at 212° Fahn: a thermometer is placed in it, and
the fire regulated by its indications. The surplus
tar adhering to the threads is first scraped off in
passing through the plates near the‘ register tube,
and is further pressed out by the compression of
the united yarns in the register tube. Z! are lids
to the tar kettle: H is the stoke-hole, and 1? n the
flue.
By this process, the tar- is made to cover the fibres,
and fill - the interstices of the yarns, thereby aggluti-
nating them into an elastic substance, almost impe-
netrable by water or damp, and well adapted for
hawsers, standing rigging, and other kinds of cordage
exposed to the weather. But it is found that in
proportion as it resists wet, it becomes rigid, and less
applicable to running rigging. For the latter puré


enclosure of brickwork. The boiler, or tar-kettle, K,
Fig. 1911, is covered byacasing, or funnelew, for carry-
ing off the fumes through the roof into the air. The
number of yarns required for the strand being settled,
that number of reels r r is arranged in several series
upon a vertical square frame of wood r F. The ends of all
the yarns from these reels are brought in a converging
direction across the apartment to a square iron plate 12,
perforated with a number of round holes, each yarn
passing through a separate hole; the ends are then
brought, in a parallel direction, obliquely downwards
to another similar plate i, ‘fixed in the middle of the
tar-kettle, and are then directed horizontally towards
and through another plate i, perforated in like manner;
then, upwards obliquely through a fourth similar
plate 12, and they afterwards pass horizontally to a

TARRIN G THE YARNS.
pose, therefore, the cold register is used; that is,
as the yarns are tarred, they are wound upon reels;
and these being fixed in a framework, the yarns are
passed through the holes of the register plate, into a
register tube, where the united yarns are forced into
a strand, and twisted as before.
This register tube consists of two compressing
plates, or dies,-—the lower one fixed in a stout frame-
work, and the upper one working vertically in a
grooved guide. The upper die is brought down, so
as to form a hole of the required size, and is held in
its position by a weighted lever. While the strand
is passing between these dies, the superfluous tar
pressed out is received into a can below.
The machine for twisting the strand while in the
register tube, besides giving the requisite degree of
twist to the united bundle of yarns, while the com-
pression is being effected in the register plate,~draws
forward the strand thus formed, and winds it in
regular coils upon a drum. This registering machine
consists of a square frame of wood a a, supported hori-
zontally upon two fixed gudgeons, b b, Fig. 1912,1u1p0n
which this frame, together with the apparatus con-
tained within it, is made to revolve. The strand
enters this frame through one of the gudgeons upon
which the frame revolves,—this gudgeon being made
hollow for the purpose,——‘and the strand is kept'tight
' ROPE.
571
by being made to pass under and over two pulleys
00 in succession, in its way to the winding drum.
These two pulleys are mounted on spindles mm, to
which motion is given by the following contrivance :—
To the hollow gudgeon is fixed a pinion j, into which
a toothed wheel A: works; this wheel is fixed on a short
spindle-Z’, supported on proper bearings; at the other
end of this short spindle is a bevel pinion Z, which
works another bevelled wheel m, attached to the
spindle that carries one of the pulleys, over and under
which the strand is coiled. At the lower part of this
same spindle is a toothed wheel m’, which acts upon a
similar wheel 12', attached to the spindle which bears
the other pulley. Now, it will be evident, that as
the whole frame revolves, these pulleys are set in
motion also; the revolution of the frame imparting

‘- III a

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l ‘ Ill
Z ‘i v-mrrmm\\\\\\_ (I


7 m
' -. a ‘
Il/Jmmihzflfuillmlllllllllnfl
a / a.
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twist to the strand, and the motion .of the pulleys
dragging it forward through the register tube.
The same motion which effects these‘ operations is
also made available for winding the finished strand
upon the drum. The pulley spindle 929 projects
through the framework, and to this projecting
end is fixed a small mitre pinion, working into a
similar pinion p’, attached to a spindle p on the outer
side of the frame. To the other end of this outer
spindle is a bevelled pinion g’, which works into a
bevelled Wheel r’, fixed to the end of the axis of the
winding drum 8. Now, a little consideration will
show, that, as the frame revolves, the two tightening
pulleys and the winding drum have each their own
distinct revolutions. As the coiling advances, the
diameter of the winding surface, or drum, goes on




Fig. 1912. HUDDART’S REGISTERING MACHINE.
enlarging, which would give an increased amount
of tension to the strand, and subject it to an unfair
strain. This, however, is prevented by an ingenious
contrivance :——the outside spindle p’ g, which trans-
mits motion from one of the pulley pinions to the
drum, is divided into two equal parts at z‘, and
united by means of a clutch, which has two frictional
surfaces, by which means, whenever the drum has a
tendency to overwind the pulleys, and thus exert an
unfair strain upon the strand, one of the frictional
surfaces slips upon the other, by which means the
drum is stationary for a small space, while the pulleys
continuing their motion, the strain upon the strand is
relieved, and the drum moves round as before. There
is also an ingenious contrivance for making the strand
pass from one side to the other of the drum, so as to
produce a regular series of uninterrupted coils. On
the opposite end of the drum is a mitre pinion,
which acts upon another similar one, attached to a
short spindle, which is furnished at its extremity
with auniversal joint u, acting upon the forked end of
an oblique spindle, which bears an endless screw,
working into a toothed wheel a; this wheel is fixed
upon the end of a spindle placed across the frame,
which spindle carries a wooden roller 90, which is thus
made to acquire a rotatory motion, in a determined
ratio to the revolution of the frame. Upon this roller
is a long, oblique, endless groove, in which a stud
is made to act; this stud projects from under the
face of the guide frame .c, to which it is attached. It
is, therefore, clear, that in proportion as the drum

revolves the roller receives from it a very slow rota-
tory motion; while this, in its turn, communicates to
the guide frame a corresponding reciprocating action,
alternately from side to side. In order to produce a
regular coil upon the drum, this reciprocating motion
must, of course, be varied in proportion to the
diameters of the different kinds of strands; and this
is provided for, by substituting for a another toothed
wheel, of different diameter. The strand is held con-
stantly in a position at right angles to the direction
in which it is coiled upon the drum, by means of two
vertical rollers, and a horizontal one 31', at the ex-
tremity of the reciprocating guide frame. Connected
with this machine is a lever, and to the gudgeon Z) is
attached a shifting friction clutch (Z, so that the ma-
chine can be set going or stopped in an instant by con-
necting or disconnecting it with the shaft 0 a, which
carries the toothed wheel 9', which in its turn is acted
on by gear-work, moved by the steam engine. There is
also a contrivance for measuring the length of the
strand as it comes into the registering apartment, by
passing over a pulley of a certain diameter, which sets
in motion a series of wheels, forming a kind of reckoner
or counter, that expresses upon a dial the number of
fathoms that have passed over the pulley. An index
being‘ set to the number required, an apparatus causes
a bell to ring when the number of fathoms has been
prepared, whereupon the attendant stops the machine.
The strand now prepared is wound off the drum upon
a loose reel, so that when transferred to the drum of
the apparatus in the next process it may become
572
.RCPE.
reversed, end for end, in which state it is ready to
undergo the operation of being formed into rope by
the laying machine.
In the formation of a good rope, it is essential that
each strand of which it is constituted should receive
an equal degree of torsion and tension, and this is
effected by means of a separate apparatus for each
strand, while the results of these distinct actions are
at the same time united by a general combination of
these motions into one centre. This partial apparatus
is called a slide-frame, and as‘ it‘ is usual to form a
rope of three strands, three spole-frames are combined.
together in this laying machine. . The steel engraving-
is an elevation of the rope-laying machine. Fig. 1913
is a section in plan through the upperportion of the




s‘.-
-
- ‘an 2 ~ a I
s .1‘ ' I- t‘
i ' 1;‘ - ‘ i ‘ii 5 if}; g .r
. a. :I r -
Fig 1913. PLAN .01‘ TOP.
machine; and Fig. 1914. is a section in plan through
the lower- part, being a section through the shaft, &c.
This machine is supported on a fixed central pillar a,
email I»
.a...


[.2 Fig. 1914. PLAN on BO’ITOM.
the foot of which rests in a solid foundation of
stone and brick-work. This pillar, just above the
masom'y, has a circular bearing turned upon it, and
- has also a strong flange on which the lower portion
of the revolv-hig framework rests). The summit of the
pillar has another circular bearing, on which the
upper portion of the framework revolves. The lower
part of this framework; consists of a large iron bevel-
wheel d,~having a series of wooden cogs- with their
. faces downward upon its outer rim, which is strength-
ened within by a .broad expansion which carries 3
vertical iron columnshwhile its arms converge into
. framework.

a strong central bush or nave, by which the whole
framework turns steadily round theeentral pillar.
The 3 columns & support a horizontal iron frame
above, which consists of 6 converging arms united by
cross stays, and a central bush, by which it works
steadily on the upright pillar a. This open cage, or
framework, carries the 3 spole-frames, each of which
bears its own separate strand. The rotation of this
framework is effected by the working into the cogged
rim of .a toothed bevel pinion e, which is driven by
the steam-engine. The spole—frames are of cast-iron,
in the form of _ a parallelogram, having in the centre
of their transverse top and bottom plates, firm
gudgeons; thelower gudgeons work in 3 steps formed
on the ‘internal rim- of the wheel cl, in intermediate
spaoes‘betweenlthe vertical columns 6, while the upper
‘gudgeona-which are hollow, work in plummer blocks
fixed to the arms of the upper framing, so that each
.spole-frame thus has ‘a gyratory motion of its own,
which it. acquires by means of a series of cog-wheels
both in‘ the upper and lower‘ parts of the general
71. _is a cog-wheel fixed upon the lower
gudgeon of each spole-frame; an intermediate toothed
wheel 9 is fixed upon one of the arms of the frame (Z,
, and works into la as well as into the head central cog-
wheel f. It will be seen, by reference to Fig. 1914.4,
that the great frame is urged round by its cogged rim
0?, so that each intermediate wheel 9 being made to
revolve'about f thus acquires, not only a general re-
volution round the central pillar, but a distinct rotatory
action about. its own centre, which gyratory motion it
communicates in an opposite direction to the wheel it,
and consequently to the spole-frame c.
In the lower compartment of each spole-frame, in
fixed bearings, is a drum 2' containing the proper
length of registered strand, and in order to preserve
a due strain upon it so as to prevent it overwinding,
clutch or friction-bands are adapted on one side of
each drum, by which any degree of vretarding force
can be applied by merely tightening a screw.
During the action of the‘ machine each strand is
wound off its drum by 2 pulleys Is to which an equal
amount of motion is imparted by' 2 cog-wheels Zr’,
which are made to turn by the bevel—wheel rz working
into the bevel pinion a’, while this is impelled by a
toothed wheel 0, and this again is acted on by a cog_
wheel 12 fixed on the-upper gudgeon of the spole-
frame, and p is set in‘ motion by another system of
gyratory wheels similar to that‘ in the lower part of
the framework. The 2 toothed-wheels pand 12',‘ on
the upper gudgeon of the’ spole-fi'ame, are of equal
diameter: 12’ communicates the impulse from the
gyratory system of ;wheels, while ]2 permits the action
of 0 around 12 during the revolution of the spole'frame,
which would otherwise be impeded by the interven-
tion of the intermediate wheel that forms part of ‘the
sun and planet motion about the central pillar.
The 3 strands being thus gradually and equally
drawn over the pulleys Is, now pass: upwards through
the upper gudgeon of the, spole-frame, made hollow
for the purpose of their curving over a series of rollers
l, which are fixed, inclined in 'a yarying manner to


10*?"
ROPE.
5'73
prevent the strands from slipping off, now all unite
into one common centre, and each, by the peculiar
revolution of its own spole-frame having received its
proper amount of torsion, they are at this point, by
the general rotation of the entire frame, all twisted
together into a rope, which is ‘carried up to an appa—
ratus where it is subject to an equal strain.
The cordage made for the used of the British Navy
is distinguished by a coloured worsted thread, intro-
duced into the centre of each strand; and every
combination of strands or rope is also distinguished
by a simple yarn, of peculiar make, laid in its centre,
thereby affording a mark of distinction from every
other rope. For the purpose of introducing this, a
reel 9% of the intended yarn is fixed upon the end of
the vertical central pillar a immediately under the
newly-forming rope, which as it proceeds carries
within it the distinguishing yarn from the reel.
At the time when the rope~making department of
Deptford Dock-yard was in activity, three of these
rope-making machines were in use: they were of
various sizes, the smaller one being used for cordage
of ordinary size, the intermediate one for larger rope
and hawsers, the more powerful one being chiefly
used for cables and hawsers of large size. It was cal-
culated that this large machine would make about 2,000
tons of cordage per annum of 313 working days,
taking the mean average of cables at from 14 to 94:
inches, and hawsers at from 7%; to 12 inches. The
second machine would make about 700 tons of
cordage per annum, taking the mean average of cable-
laid rope at from 8 to 10 inches, and hawser-laid from
51.; to 7 a; while the smaller machine would prepare
about 300 tons of cordage in the same time, taking
the mean average of cablets at from 5% to 7;‘; inches,
and shroud-laid from 3%; to 5. These three machines
were able to provide sufficient cordage to answer the
demands of the whole British Navy.1
These details will sufiice to explain the principles
upon which rope-making machinery is constructed.
Since the date of Huddart’s invention many patents
have been taken out for rope-making machines. The
visitors to the Great Exhibition must have been sur-
prised and delighted at the apparently complicated
but easy*motions of Mr. J. Orawhall’s machine by
which yarns were spun into strands, and the strands
into a rope which was wound upon a reel as fast as
it was form ed. In the Mec/zam'c’s Magazine, No. 1,417 3,
is a detailed account accompanied with wood en grav-
ings of some rope and cordage making machinery
communicated from abroad, the patent for which is
taken out in the name of Mr. Brooman and is dated
2d April, 1851.
In the manufacture of ropes, as described in this
article, we have considered hemp as the only material
used. Other kinds of vegetable fibre have been used
with advantage. It appears from some experiments

(1) The length, weight, and value of the cordage required by a
first-rate ship of war is as follows :—-
Total weight, 785 tons.
Total length, 43 miles, all the cordage, great and small, being
supposed to be tied together, and extended in a right line.
Total cost, at the average price of 42!. per ton, 3,2762.

made at Paris with ropes of hemp and of the Mac
from Algiers, that the latter bore a strain of 2,000
kilogrammes, while a hempen rope of equal size bore
only 400. Ropes have been formed of long wool, but
they have only about one third the strength of hempen
cordage of the same size. The fibres of hemp inter-
mixed with t/zreazls ofcaoufc/zouc give a rope of superior
strength and elasticity; such a rope has been used
with advantage with the grapnel or anchor of a
balloon, arresting the machine without the usual
unpleasant jerk when the grapnel catches.
Ropes of iron wire have been used with advantage
in mines. They appear to have been introduced
about 1831 into the silver mines of the Hartz moun-
tains, and were found so superior that the flat and round
ropes of hemp were soon superseded. From a state—
ment by Count Brtinner to the British Association in
1838 it appears that these ropes were nearly equal in
strength to solid bars of the same diameter, and equal
to hempen ropes of 4! times their weight. One of
them had been in use for upwards of two years with-
out any perceptible wear, although a common flat
rope performing the same work would not have lasted
much more than one year. The diameter of the
largest rope in ordinary use is about 1% inch: it is
composed of 3 strands, each containing 5 wires of 2
lines in diameter. Care is taken that the ends of the
wires may be set deep in the interior of the rope, and
that 2 ends may not occur near the same part. In
using these ropes they require to be wound on a large
drum, not less than 8 feet diameter, and be kept
coated with tar to prevent oxidation. The use of the
wire rope economises horse power.
Patents have at various times been taken out in
this country for the manufacture of wire ropes. Mr.
Andrew Smith’s wire ropes have been used in mines,
for the rigging of ships, and for other purposes, among
which may be mentioned the drawing of the trains in
the London and Blackwall railway before the intro-
duction of locomotives on that line. These ropes are
formed in various ways according to the uses to which
they are to be applied. For standing rigging straight
untwisted wires are bound round with cloth or small
hempen cordage saturated with a solution of caout-
chouc, asphaltum or other preservative against rust.
Flat ropes are made of straight wires or wires with a
slight twist, interwoven or wrapped with hempen yarn
or sewed between canvas. Other ropes are formed
after the method of hempen ropes, the wires being
twisted into strands, and combined into ropes either
hawser-laid or cable-laid. The torsion must not be
so hard as in hempen ropes, and the wires must be
coated with tin or zinc, or other protective from rust.
Mr. Newall recommends the following composition
for the coating :--Tar 6 parts, linseed oil 2, tallow 1
part; the whole to be melted together and applied
while hot. In Mr. Newall’s patent the wires are
twisted round a core of wire, hemp cord, spun yarn,
or other material to form a strand; and if more than
3 strands are used in a rope they are laid round a
similar core. In joining the wires the ends should be
twisted together for a few inches or even soldered or
5 7'1!
ROSE MA RY—RUMBLE-wRUsl-I—TRYE.
welded. Wire ropes may be secured at their ends by
passing them through the small end of a conical collar,
and doubling up or upsetting the ends of the wires,
which may then be welded into a solid mass, or
secured by running melted brass or solder among
them. The collars may then be attached to the hook,
eye or joint with which it is required to connect the
rope, or they may be screwed together so as to unite
several lengths of rope.
Copper, brass and other metals are also used for
wire ropes, some of which are made of small size for
hanging pictures, 850.
The comparative size and weight per fathom for
equal strengths of hemp and wire ropes are given in
the following table, the results of experiments with
Mr. Andrew Smith’s wire ropes :--
HeMr noun. Winn nope.
Weight Weight EQUAL
Size. per fathom. Size. per fat/mm. to a strain of
Inches. lbs. oz. Inches. lbs. oz. tons. cwt.
3 .... .. 2 4 .... .. 1k .... .. 1 4 .... .. 2 10
4- .... .. 315 .... .. 1% .... .. l 9 3 10
5 .... .. 6 0 .... .. 1'5} .. 114 .... .. 6 15
6 . 9 0 .... .. 2 .... .. 2 2 .... .. 8 0
7 .... .. l2 3 .... .. 2,’; .... .. 2 9 .... .. 8 ll
8 .... .. 14 3 .... .. 2s .... .. 4 1 9 18
9 .... .. 19 6 .... .. 3 .... .. 5 4 .... .. 15 6
10 .... .. 25 0 .... .. 3,’,~ .... .. 7 1 .... .. 2'! 6-
ll .... .. 3O 0 .... .. 4 .... .. ll 6 .... .. 29 5
12 .... .. 36 8 .... .. 4% .... .. 15 12 .... .. 35 4
ROSE-ENGINE. See TURNING.
ROSEMARY, OIL or‘, an essential oil prepared
chiefly in Spain and the south of France by distilling
the leaves and flowers of the Rosmarz'rws ofiicz'rmlz's.
At first it is nearly transparent and very limpid ; but
it becomes yellowish and thick by age. It has the
strong penetrating odour of the plant, with a camphor-
like addition: its taste is burning and it has an acid
reaction. The sp. gr. is about 0'91, but it varies
with the age and purity of the oil. It mixes freely
with alcohol. 13y evaporation or by shaking it up
with potash it deposits a stearoptene or rosemary-cam-
p/ror. The oil of the rosemary of commerce is prepared
from oil of turpentine distilled with rosemary; it is
also adulterated-with spike oil. This artificial pre—
paration does not redden litmus.
Oil of rosemary is chiefly used as a perfume. It
enters into the composition of Hungary water, eau
de cologne and aromatic vinegar: it is also said to
promote the growth of hair and to prevent baldness.
Distilled oil of rosemary according to Dumas has a sp.
gr. of 0385 to 0'887, and consists of C80 1164+21‘IO;
that is, a hydrate of a hydrocarbon, isomeric with the
distillate of oil of turpentine.
ROSIN. See TURPENTINE.
ROSIN GAS. See Gas.
RO'l‘, DRY. See TIMBER.
ROTTEN-STONE. A variety of TmroLI, almost
peculiar to England. It occurs abundantly in Derby-
shirc and South Wales, and is much used for giving
polish and lustre to articles in silver, glass, and stone.
See GRINDING“ and PoLIsnINe.
ROUGE. See SxrrLownn—CAnMINn.
RUBBLE-WORK. See MAsoNnY.
RUBY. See Sxrrnrnn.

RUDDER. See SHIP. .
RUM, a spirit distilled in the West and East
Indies from a fermented mixture of molasses and
water, with the skimmings from the sugar boilers
and the (lender, or lees, or spirit wash of former dis-
tillations. The average strength of rum is 53 to 5d
per cent. of alcohol, sp. gr. 0325 at 60°. The flavour
of rum is referred to an oily product, probably formed
during fermentation, and to which the sudorific pro-
perty of rum is ascribed. [See Susan]
RUMBLE, or SHARING MACHINE, a cylindrical
vessel like a churn, used for polishing small articles
by their mutual attrition. It is usually made to re-
volve by a winch-handle or pulley; but is sometimes
shaken endways by a crank so as to imitate the mode
of cleaning nails by shaking them in a sack, whence
it derives its second name.
The rumble is used for polishing needles and brass
pins with sawdust and bran; steel pens, with saw-
dust, after the hardening and tempering; bone but-
tons, with Trent sand; lead shot, with black-lead;
for securing small castings to remove the sand coat;
for brightening iron tacks with water before being
tinned; for cleaning the rust off cannon balls; for
drying small articles in sawdust, such as the blanks
for coin, after they have been annealed and pickled
with acid ; for dissolving gums in spirits of wine, for
making lackers and varnishes: such are a few of the
uses to which the rumble is applied.
RUSH. The application of the common soft rush
(famous efiizrsus) to the making of rush-lights is ex—
plained under CANDLE. The J. efasus and the J. 0022—
glomeraz‘us, or the common rush, are used for plaiting
into mats, chair-bottoms, and for making small baskets.
The Dutch rush (Equz'sezfum Izyemale) is used for polish-
ing hard woods, alabaster, marbles, and some other
substances, for which it is adapted by the quantity of
silica disseminated through its outer surface. The
rush is about the size of a writing quill, of agreenish-
grey colour, and a rough grooved surface ; it is
gathered in pieces from 2 to 3 feet long, which are
intersected by knots at distances of 11 to 6 inches.
It is said to be a native of Scotland: it thrives in the
marshy places of mountainous districts. It contains
rather more than 13 per cent. of ash, which consists
of silica 6'38, carbonate of lime, 5'51, potash salts
0'7 9, and alumina 0116.
RUST, a term applied to the red oxide of iron,
which forms on the surface of iron by exposure to air
and moisture.
RYE, a plant of the family of the Gramineee, hear-
ing naked seeds on a flat ear furnished with awns
like barley. Its straw is valuable for thatching, and
also for litter. Rye is extensively cultivated on the
Continent, especially in the Netherlands, where it
is used for distilling the spirit named Hollands: this
is flavoured with juniper, or, as the Dutch call it,
genever, whence the name yeneva and its contraction-
gz'rz. When rye is malted it makes beer of good qua-
lity. According to Einhof rye consists of husks
24'2, flour 65'6, and water 102 per cent. The flour
contained 6107 per cent. of starch, 948 of gluten,
SAFFLOWER—-SAFFRON.
575
3 28 of vegetable albumen, 3 28 of uncrystallizable
sugar, 1109 of gum, 6'38 vegetable fibre, and the
loss was 5'62. Phosphates of lime and of magnesia
were also present.
SABLE. See FUR.
SACGHAROMETER. See BEER, Fig. 111.
SAFETY-LAMP. See COAL, Figs. 576, 577.
SAFETY-VALVE. See STEAM.
SAFFLO WEB, the dried flowers of Cart/mews
tz'rzctorz'us, the chemical principles of which are given
under GARTHAMUS. It is an annual composite plant,
cultivated in India, Egypt, Spain, and the Levant, &c.
on account of its dyeing properties. The flowers are
the only parts used in dyeing: these yield two sorts
of colouring matter; the first yellow, and of little
value; the second, a pink of great delicacy and beauty,
but not very permanent. The yellow colour of saf-
flower is soluble in water, the pink is resinous in its
nature, and is best dissolved by the fixed alkalies.
The flowers of the carthamus are gathered, placed in
a bag, and trodden under water to get rid of the yel-
low colour. They are then placed in a trough with
soda, in the proportion of 6 lbs. to 120 lbs. of cartha-
mus. After soaking for a time, the contents of the
trough are transferred to another, having a perforated
bottom, but lined with a finely-woven cloth. This
perforated trough is placed over an unperforated
empty one, and water is poured through the upper
one. This carries with it a large amount of the
colouring matter released by the alkali. When the
lower trough is full the bath is placed over another
trough. A little more alkali is added and fresh water,
until the latter runs through without carrying any
more colouring matter. Lemon juice is added to the
dye stuff in the troughs, and raises the colour to a
bright cherry-red. Silk, in hanks, is then immersed
and turned round skein-sticks in the bath as long as
it will take up any colour. It is then dried, and if
the colour be not deep enough, it is passed through
another bath of similar strength. A final brightening
is given by turning the silk round the skein-sticks 7
or 8 times in warm water with lemon—j nice, in the pro-
portion of half a pint to each pailful of water.
This colour will not bear the action of soap, nor
will it long withstand exposure to the sun and air; it
is chiefly employed on silk for imitating the fine dye
of the French called porzceau. For porzeeau, or flame-
colour, the silk is first boiled, and then receives a
slight foundation of annotto; but it must not be
alumed.
Saiflower is a costly dye: it is chosen in flakes of a
bright pink colour; that in powder, dark-coloured, or
oily, is of inferior quality. The beauty of the colour,
in its purest form, has caused it to be employed in the
manufacture of rouge. The preparation of rouge from
cochineal is described under CAIBMINE. The delicate
and beautiful rouge, known as rouge cégétale, is nothing
more than the colour of safflower which has been ex-
tracted by means of crystallized soda, precipitated by
citric acid, then slowly dried, and ground up with the
purest talc. Dr. Ure’s account of the process of
rouge-making from safflower is as follows: “The

flowers, after being washed with pure water till it
comes off colourless, are dried, pulverized, and digested
with a. weak solution of crystals of soda, which as-
sumes thereby a yellow colour. Into this liquor a
quantity of finely carded white cotton wool is plunged,
and then so much lemon~juice or pure vinegar is
added as to supersaturate the soda. The colouring
matter is disengaged, and falls down in an impalpable
powder upon the cotton filaments. The cotton, after
being washed in cold water, to remove some yellow
colouring particles, is to be treated with a fresh
solution of carbonate of soda, which takes up the red
colouring matter in a state of purity. Before pre-
cipitating this pigment a second time by the acid of
lemons, some soft powdered talc should be laid in the
bottom of the vessel for the purpose of absorbing the
fine rouge, in proportion as it is separated from the
carbonate of soda, which now holds it dissolved. The
coloured mixture must be finally triturated with a few
drops of olive-oil in order to make it smooth and
marrowy. Upon the fineness of the tale, and the pro-
portion of the safliower precipitate which it contains,
depends the beauty and value of the cosmetic. The
rouge of the above second precipitation is received
sometimes upon bits of fine-twisted woollen stuff,
called creporzs, which ladies rub upon their cheeks.”
SAFFRON consists of the stigmata of the flowers
of a perennial bulbous plant (Crocus satz'ous), once
extensively cultivated at Saffron Walden in Essex,
and still fostered in some parts of Cambridgeshire.
From this small portion of the flower is obtained a
rich yellow-red colour, which, when dried and pure,
is of a scarlet hue. Saffron is imported from Sicily,
France, and Spain, but the foreign product is not so
much esteemed as the English. The use of saffron is,
however, diminishing. It is employed as a seasoning
in cookery: also to colour confectionary, liqueurs,
varnishes, and sometimes cheese and butter. It is
used to a small extent by painters and dyers. It was
formerly much used in medicine as a carminative,
antispasmodic and emmenagogue, and it is still occa-
sionally employed to promote the eruption of certain
diseases of the skin. On the same principle it is given
to birds to assist their moulting. Dr. Lindley de-
scribes the colouring ingredient of this plant as “a
peculiar principle to which the name of Polychroite
has been given; it possesses the properties of being
totally destroyed by the action of the solar rays, of
colouring in small quantity a large body of water, and
of forming blue or green tints when treated with sul-
phuric and nitric acid, or with sulphate of iron. In
moderate doses, this substance stimulates the stomach,
and in large quantities, excites the vascular system.
Moreover it seems to have a specific influence on the
cerebro-spinal system, as it affects, it is said, the
mental faculties, a result which De Candolle considers
analogous to that produced by the petals of certain
odorous flowers.” Saffron is known in commerce as
a kind of fibrous cake. This should be moderately
moist, close, tough, and compact, the smell sweet and
penetrating, the taste warm, pungent, and somewhat
bitter.
576
S AL AMMON'IAC—SALEP— SAND.
SAGO. See S'rancn.
SAIL, a coarse linen or canvas sheet attached to
the masts and yards of ships, the blades of windmills,
&c., for the purpose of intercepting the wind, and
occasioning their motion. See SHIP—WINDMILL.
SAL AMMONIAC, a compound of ammonia and
hydrochloric acid, NH3,HCI, now called lzgdi'oelilo-
i‘aie of ammonia, although the older term, nzzn'iaie of
ammonia, is also used. The substance from which
this salt was first obtained, was the sect of camel’s
dung; and it was formerly produced therefrom by-
sublimation in large. quantities, in Egypt, near the
temple of Jupiter Ammon, whence the name sal
ammoniac. It is now manufactured largely in Europe,
by combining hydrochloric acid either directly or in-
directly with ammonia obtained from the decomposi-
tion of animal matter. In France, bones and other
animal matters are distilled in large iron retorts, for
the manufacture both of animal charcoal and of sal
ammoniac. Coal soot was formerly used in Great
Britain as a source of this salt; but since the
establishment of gas works, it has been chiefly de-
rived from the liquor obtained during the preparation
of coal gas. [See Gas] The impure carbonate of
ammonia contained in this liquor is either at once
saturated with hydrochloric acid, or it is first con—
verted into sulphate of ammonia, and afterwards by
decomposing it with common salt into hydrochlorate;
the products being sulphate of soda and hydrochlorate-
of ammonia: the latter is separated by crystallization
and sublimation. This salt, as obtained by sublima-
tion, is amorphous, somewhat elastic, translucent, and
colourless; and of the sp. gr. 1445 to 1'50, but when
obtained by crystallization, its form is octohedral and
cubic. Its taste is sharp and saline : it has no smell ;
it dissolves readily in water; it does not change in
dry air, and volatilizes by heat, without undergoing de-
composition. It is decomposed by lime, and the fixed
alkalies, with the evolution of ammoniacal gas: sul-
phuric acid expels hydrochloric acid gas from it.
Sal ammoniac is used in the arts for a variety of
purposes; as in pharmacy for making ammoniacal
preparations :' in tinning, to prevent the oxidation of
the surface of the copper: when dissolved in nitric
acid it forms the aqua regia of commerce, used for
dissolving gold instead of nitrohydrochloric acid. It
is also used in small quantities in steam boilers, to
prevent the formation of calcareous deposits.
SALEP. This nutritive mucilaginous substance is
obtained from the subterraneous succulent roots of
several species of orchis, especially Ore/air maseala,
thus forming one of the few exceptions to the general
rule; that orchidaceous plants, which charm and
astonish by their elegant, varied, or grotesque forms
are without known utility to man. Salep is apowder
prepared from their dried roots; in some cases, as in
that imported from India, it is in hard clear pellucid
inodorous pieces. There is not much demand for
this substance, although it is considered a bland and
nutritious article of diet, taken with milk, in the same
way as arrowroot. The orchis which yields it thrives
well in England, but is not cultivated to any extent.

SALICINE, a peculiar, crystallizable, bitter prin-
ciple, obtained from the leaves and young bark of the
poplar, willow, aspen, 850. It forms small white silky
needles, and in some respects, resembles the vegeto-
alkalis, cinchona, and qnina, having febrifuge proper—
ties; but it differs from them in containing no ni-
trogen, and not forming salts with acids. Its for-
mula is said to be CzfiHlsOu.
SAL PRUNELLA, a term applied to nitrate of
potash, fused and cast into balls resembling prunes or
plums, and sometimes coloured to resemble them.
SAL VOLATILE. See AMMONIA.
SALT, EPSOM. See Maennsrx, snip/rate of.
SALT, MICROCOSMIC, the triple phosphate of
soda and ammonia. See MrcnocosMrc SALT.
SALT OF AMBER is succinic acid. See AMEEE.
SALT OF LEMONS. This term can only be
correctly applied to OITRIC AcID; but the oxalate of
potash used for removing iron moulds is called by this
name. See OXALIG AcID.
SALT OF SATURN is the acetate of lead. See
LEAD. -
SALT OF SODA is carbonate of soda. See
SODIUM.
SALT OF SORBEL is binoxalate of potash.
See OXALIC AcID.
SALT OF TABTAB. is carbonate of potash, so
called from its being obtained by burning purified
tartar, (bitartrate‘of potash,) lixiviating the residue,
and evaporating to dryness.
SALT OF TIN, the protochloride of tin.
SALT OF VITRIOL, a term applied to white
vitriol, or sulphate of zinc.
SALT PERLATE is phosphate of soda.
SALTPETRE is nitrate of potash. See POTAS-
sIUM.
SALT, SEA or CULINARY. See SODIUM.
SALT SEDATIVE is boracic acid.
SALTS. See METAL.
SAND. This name is popularly applied to any com-
minuted minerals, but properly belongs to granular
quartz, silica, or flint, the chief ingredient in the
sands of the deserts, sea-shores, river banks and soil.
Sand is produced by the disintegration of rocks, and
its colour, which is generally imparted by oxide of
iron, may be red, white, grey, or black. The pure
colourless sands are much in request for the manu-
facture of glass. [See Gnass] Sand is also used
for making mortars, [see Mon'rans and CEMEnTs,]
for filters, [see FILTEATIONJ and in the operation
of founding, [see CASTING and FOUND1NG.] Sand is
also used in sawing and smoothing building stones
and marbles, [see MARBLEJ and in many other
grinding and polishing operations. River and pit sand
are usually sharper than sea sand, for this has been
rounded by attrition. The washed scrapings of roads
which have been repaired with flints furnish the sand-
used by stone masons. Grinrlsione dust is ' a form of
sand useful for some purposes; it cuts deeper than‘
Flanders brie/c, which is another form in which sand
is used. Grindstone dust- is formed during the turng
ing of the grindstone into form, or it may be made
SAND—SANDSTONE—SANDAL WOOD...
577
by crushing the grit or grindstone with a hammer, or
with a pestle and mortar. Trent‘ sand is a fine and
sharp sand, collected from the banks of the Trent,
which flows into the Humber. This sand is much
used at Sheffield and other places for polishing; it is
an economical substitute for emery and other polish-
ing powders, and is much used for Britannia metal
goods. The Shelfield cutlers make this sand into
balls, which they put in the fire for a few hours; they
are then crushed and passed through a fine hair
sieve; this burnt sand is thought to cut more readily
than the unburnt. Blue grit stone crushed and pul-
verised is used for common cutlers’ work. Flander’s
or Bat/t ér'z'cks are made at Bridgewater, of a clay
containing a large proportion of fine sand; they are
much used for domestic purposes, and also in the state
of powder for polishing bone, ivory, and soft metals;
and in dressing cutler’s dry buff wheels. Sand-paper
is made of common house sand of one degree of
coarseness; it is less useful than glass-paper when
applied to wood, but its effect on metals is intermediate
between that of glass-paper and emery-paper. Sand-
paper is prepared in the same manner as glass-paper.
As the latter useful article was not noticed under its
proper heading, it may find an appropriate place here.
In making glass-paper, fragments of broken wine
bottles are well washed to remove the dirt; the glass
is crushed under an edge runner, and then sifted
into about six sizes. The paper is brushed over with
glue, the glass, dusted over it from a sieve. Thin
cotton cloth is also used instead of paper; and
Venetian red is sometimes mixed with the glue for
the sake of the colour. Calcined flint has also been
used instead of the glass. [See EMnnr—Gnrnmne
and Ponrsnmca]
The use of sand as a measure of time is noticed
under HOROLOGY. It is stated in that article that
the flow of sand, unlike that of water, is perfectly
equable. In the sand or hour-glass, for example; there
is an equable flow from the upper into the lower bulb
whatever quantity of sand be above the aperture; and
the larger quantity of sand does not, as in the case of
water, act by its weight or pressure in accelerating
the flow. This may be proved by a few experiments.1
A glass tube of any length and diameter is to have
its lower extremity closed with a piece of writing
paper, the edges of which may be secured with string
to the outside of the tube. A small hole about ls-th
inch inrdiameter is to be made in the centre of the
paper bottom, and the finger being placed on this hole,
the tube is to be filled up with fine dry sand. If the
tube be suspended and portions of the sand allowed
to flow out, each portion suificient to fill a small cup,
the time required to fill this cup will always be the
same. Or if the tube he graduated on the outside
the time occupied by the sand falling from one division
to another will be found to be the same in any part
of the tube. This would'evidently not be the case

(1) These experiments, and further particulars respecting the
hour-glass, are given in the Editor’s “ Student’s Manual of
Natural Philosophy.” 1838.
'V OL. II.

with water. When the sand is flowing, any pressure
exerted on the upper surface of the sand will have no
effect in accelerating the flow. If the bottom of the
tube be closed with a thin film of silver paper, and a
solid cylindrical plug be rammed in at the top, no
force that we can exert will displace the paper at the
bottom.
To explain these remarkable phenomena it must
first be noticed that when sand is allowed to fall
quietly upon a plain surface it forms a conical heap,
the sides of which form with the base, an angle of
about 30°. Now when the sand is poured into the
tube it forms therein a succession of conical heaps
which support each other and rest against the sides
of the tube, the last heap only being supported by the
paper bottom. Now when any pressure is applied
to the top surface of the sand it is not transmitted,
as in the case of water; it acts to a very small depth
laterally, but has no perpendicular action. Hence we
see that the reason why the sand flows so equably in
the sand-glass, &c., is that the lowest heap is not in-
fluenced by the pressure of the heaps above. This
shows us also how it is that sand is so excellent a
tamping material for filling up the holes made for the
gunpowder in blasting; [See Minn—MINING, Fig.
1465]. The pressure not being transmitted by the
sand the force of the gunpowder is not wasted by dis-
charging smoke and dust into the air, but acts with
full effect upon the rock which is to be severed.
SANDSTONE, an aggregation of sand by a sort of
semifusion as in quartz rock, and in common grit-
stone, adjoining trap dykes or- great faults. [See
COAL, Figs. 571, 57 2. See also Gnrnns'ronn—Gmr]
In many of the white sandstones the grains merely
cohere together. In the sandstones of coal tracks the
finer particles of carbonate of lime, clay, oxide of
iron, &c., are interposed between the grains: in other
cases, as in the Hastings sandstones, an infiltration
of carbonate of lime has taken place. Some sand-
stones are in laminae, plane, waved, or slightly con-
centric: these admit of being readily split. The
freestones [see Fnnns'ronn] are not distinctly lami—
nated, the grains being so arranged as to present
equal resistance in every direction. They work finely
under the stone saw (Fig. 1393) and the ordinary
picks and ehisels. They can also be turned into
balustrades, pedestals and vases.
SANDAL WOOD, a fragrant wood much used
among the Chinese in cabinet work, and in the manu—
facture of fans and other ornamental works. It is
the produce of a small tree (Santalum album) growing
in India and Ceylon, which gives its title to the
natural order of plants called Sarzialaceaa or Sandal-
worts. The sandal—wood of the Sandwich islands is
from two other species of the same family, S. Freycz'ne-
tiammz and S. pa'gzz'culatum. In the native medical
practice of India; Sandal-wood furnishes a sedative
cooling medicine; it is also largely employed as a
perfume in the funeral ceremonies of the Hindoos.
By the Chinese it is ground into powder and used as
a cosmetic. The bark affords a beautiful red dye,
but so fugitive as to be useless. The tree grows
r r
578
SANDAItAOH~SAPPHIRE—SARSAPAB.ILLA—S AW.
freely among the mountains of Malabar, near the sea-
coast, whence Calcutta obtains her supply of sandal
wood, and in Timor and the Feejee islands, from
which China derives her chief supply.
The tree is out down when about 9 inches diameter
at the root: it is then cleared of its bark, and cut
into logs, which are buried for six weeks or two
months‘ in order that the white‘ants may clear off the
outer wood; this they do most effectually, without
touching the heart of the tree, which is the only
valuable part. Sandal-wood should be of a fine deep
yellow ‘brown, and highly perfumed. The average
importation of this wood into Calcutta is 200
tons per annum. The Chinese imported an amount
of sandal—wood in 1838 worth about one hundred and
fifty-thousand dollars, but this is said to be doubled
in some years. The supply to Europe is very small,
and chiefly derived from that which has been brought
over by individuals without a view to commerce.
SANDARAOH, a resinous substance, said by
some writers to exude in hot climates from the bark
of the common juniper-tree (Jzmiperz's commemz's).
Other state it to be produced by another tree of the
pine tribe called T/zuja m'tz'calam, but according to
Brongniart and Schousboe, it is the tears of Callz'trz's '
guadrz'valm's, also a coniferous tree. Dr. Lindley
says, “I have seen a plank two feet wide of this
sandarach tree, which is called the arar tree in
Barbary. The wood is considered by the Turks in-
destructible, and they use it for the ceilings and floors
of their mosques.” The resin is received in the form
of loose granules or tears, whitish yellow, brittle, and
having a faint resinous smell, and acrid taste. It is
. used, dissolved in spirits, as a varnish; it is also
employed as incense, and as a pounce-powder.
. SAPPHIRE, a gem of a blue colour consisting
of pure alumina; it occurs in six-sided prisms often
with uneven surfaces. It also occurs granular. When
the surface is polished, a star of six rays correspond-
ing with the hexagonal form, is in some specimens
seen within the crystal.‘ The sapphire ranks next to
the diamond in hardness. When it occurs in dull
dingy-coloured crystals and masses, the term commdum
is applied to it, and the granular variety of bluish grey
and blackish is called emery. [See EMERY.] When
the sapphire occurs of other brig/at tints other names
are applied to it, a list of which is given in the tables
of hardness under LAPIDAnY WORK. The application
of ‘the sapphire to the JEWELLING or WATCHES is
given under that head.
Some of the varieties of the sapphire rank next to
the diamond in value. Indeed the oriental ruby, of
fine colour and free from flaws, is more valuable than
a diamond of equal weight. In Mr. Hope’s collection
is a blue sapphire which cost 3,000Z.
SARD, SABDONYX. See AGATE.
SARSALPARILLA. The roots of several species
of climbing evergreen plants found mostly in warm
and tropical climates, and belonging to the genus
Smilax. The name sarsaparilla is derived from the
Spanish word zm'za, a bramble, and parz'lla, a vine.
The original species, Smilax qfiiez'azalz's, is a native of

South America, but there are several other kinds
which also contribute to furnish the roots known in
commerce as genuine sarsaparilla, and whose pro-
perties are scarcely inferior to it. Of the South
American sarsapairilla some reaches us by way of
Jamaica and has the name of that island, while a
large quantity is shipped at the Brazils and is called
Lisbon sarsaparilla. Varieties of this root are also
found in the South of Europe and in India. East
Indian sarsaparilla, long thought to be the root of
smz'Zaa'. aspem, but nowr said to belong to Hemz'desmas
Irzdz'cus, is abundant and cheap, and as it appears to
partake largely of the qualities of the true sarsaparilla,
there is no doubt of its being extensively employed as
a substitute. .
Sarsaparilla is valued as a restorative to debilitated
constitutions. According to Brande there. is as yet
no good analysis of this root, and the extraordinary
medical qualities which it is said to possess are to be
attributed rather to its general composition than to
any distinct principle.
SATIN. See WEAVING.
SATIN-SPAR is a variety of fibrous gypsum. See
GYPSUM.
SATURATION. See SOLUTION.
‘SAW, an important cutting instrument used in the
preparatory processes of reducing wood, ivory, and
other substances, to shape. It is not much used for
the metals: the desired forms being given to them
by casting, hammering, rolling, filing, &c. A good
saw ought to be of uniform thickness in the blade,
and so elastic, that when bent into a bow it will spring
back again to a straight line on removing the pressure.
These qualities are best ensured by cutting the blade
out of a sheet of steel formed by rolling an ingot of
the cast 'metal. If intended for a mill or pit—saw, a
large sheet is clipped with shears to the proper shape :
for smaller saws, the sheet is cut up into the required
sizes.‘ The shears used for the purpose are arranged
with due regard to strength and stability, the upper
blade being raised and depressed with a long lever, as
The edges of the pieces are
shown in Fig. 1915.






lim '
/
up _, l
.1.’ Y




1 H __X'
M ,


4.2?"
~
CUTTING- OUT THE BLADES.
Fig. 1915.
ground true by holding them against a large grind-
stone, as shown in Fig. 1916. The teeth are cut out
l by a punch at a fly—press [see PUNCHING, Fig. 1802],
saw}
579
the distance between the teeth being accurately regu-
lated by an upright steel gage by the side of the
cutting-punch, and shifting the blade one tooth for-


















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, lllllll '- - - —~ ~ '
l l- "! . . h‘
"l l l '5 ~ _, ._-V,\ .1 ‘L 4'
“a ll
/ _ r . ‘4|
i . - {"6711 ~— —~.- ,7, ‘)7 -- -
- it '..|-
~. a ' ,- —
_._. ‘a 1 ‘IN, _ . . _. J A: 3’, --:_
m' I'd“ ' __ ‘7 lliy‘ ~ f’:-
---~--:'* * _ <, ,- ___-_. i
\ _l_€-‘ _~_-~ m ‘ll-‘ilk. ,'
- l


" ‘. “Pt?! I’
ll 5%‘ ; ill

' l l r -
_...—_:':-——‘" .
_, —— -~_“

/
Fig. 1916. GRINDING run ‘BLADES.
wardafter the cutting of each tooth, the gage falling
into the space between two teeth. In cutting the
teeth of long saws, which are too heavy and pliable
to be held in the hand, the ends are supported by
swing—rests suspended from the ceiling by cords. The
forms of teeth are very various, and will be noticed
more particularly hereafter. Fine saw-teeth may be
‘ indented with a double chisel, one edge of which is
inserted each time in the notch previously made, and
‘the other edge makes the following indentation: the
intervals, thus being truly equidistant, the teeth are
completed with a file. Piercing or inlaying saws are
[made from pieces of watch-spring, straightened by rub-
bing them the reverse way of their curvature through a
greasy rag: these saws are about 56th inch wide,
u‘mth inch thick, and have about 20 points to the inch
for wood, 30 for ivory, 4:0 for ebony and pearl, and
60 for metals. The saw is made by being distended
in a frame, laid in a shallow groove in a plate of brass
imbedded in wood, and the teeth are set out with a
file by a process of stepping, during which the file
rests alternately on the saw blade and on the edge of
the block. But to return to the manufacture of the
larger and more common varieties of saws. After
the teeth are cut the blade is put into a vice, and the
wire edges left by the punch are filed down, and the
teeth are sltmpenecl. The next process is hardening.
Saws require a milder degree of hardness than is ob-
tained by raising the metal to a red heat and quench-
ing in water. The proper degree of hardness is
obtained by quenching in a bath of oil in which
various ingredients, such as tallow, suet, bees’-wax,

‘resin, pitch, 850., have been melted. The saws are
heated in long furnaces, and then immersed horizon-
tally and edgeways into a long trough containing the
composition. It is usual to employ two troughs, the
second being brought into service when the first gets
too hot. When the saws are removed from the trough
they are very hard and brittle, and require tempering;
for which purpose a portion of the composition is
wiped ofi with a piece of leather, and each saw is

heated over a coke fire until the grease inflames, an
operation which is called blazing mfl If the saws arc
to be rather hard, only a small portion of the grease
is blazed ofi.’ ; but a larger portion for a mild temper.l
The composition loses its property of hardening steel
after a few weeks’ constant use. The trough should
be well cleaned out before a new mixture is put into
it. Mr. Gill recommends for the composition 20 gal-
lons of spermaceti oil, QOlbs. of beef suet (rendered),
1 gallon of neats’-foot oil, 1 lb. of pitch, 3 lbs. of black
resin. The pitch and the resin are to be melted
together before being added to the other ingredients.
The whole is heated in an iron vessel with a closely-
fitting cover, until the moisture is nearly driven off,
and the composition inflames on presenting a burning
body to its surface. The flame must however be in-
stantly extinguished by putting on the cover. In
tempering large saws they are stretched in an iron
frame moving on wheels, so that they can be returned
to the furnace and moved to and fro over the fire
until the grease begins to blaze off. They are then
removed from the furnace and allowed to cool, and
occasionally stretched tighter in the frame to prevent
warping. Bade-saws, or those which are afterwards
furnished with a brass or iron back to keep them
straight, are made inlengths of several feet, and at
a subsequent stage are cut up into 3 or 4: saws. These
lengths are hardened and tempered in the same man-
ner as large saws; but saws of medium size are tem-
pered by holding them one at a time with a pair of
tongs, and moving them over a fire for the blazing-off.
The next operation is plane's/ting or snzz't/zz'ng, for
which purpose the saw is rested on an anvil of polished
steel, and hammered over every part of its surface,
more in some parts than others, according to the
judgment of the workman, the object being to impart
to the metal an equal density and elasticity through-
out.2 The internal texture having been thus equalized,
the blade is ground at the wheel or grindstone, Fig.
1916. The stones are from 5 to 7 feet in diameter,
and 10 or 12 inches across the face : the grinding is
wet, and the saw is applied to the stone chiefly cross-
ways so as to reduce the thickness of the metal from
the teeth towards the back: the blade is placed
against a board, upon which the grinder presses and
moves it about during the grinding. The larger saws
are suspended at both ends from the top of the mill.
The flatness and elasticity of the saw have been
impaired by the grinding: it is therefore planished a
second time to restore its flatness: it also partly
receives its elaslicityin this process and partly by the
next, which consists in holding it over a coke fire
until a faint straw colour appears. It is now passed
lightly over the grindstone in the direction of its
length in order to remove the marks of the hammer,
and is next smoothed upon a hard smooth stone. It

(1) In tempering clock-springs the whole of the grease is burnt
ofi‘.
(2) On this subject we may refer to a very instructive section
in the 18th chapter of Holtzapfi‘el’s “ Mechanical Manipulation,”
entitled “The Principles and Practice of Flattening thin Plates
of Metal with the Hammer.”
1? P 2
580
S AW.
is polished upon a hufi' or glazer, and again planished
or bloc/cell, as it is called—the anvil being a block of
hard wood. The saw is next cleaned of by women,
with coarse emery, rubbed on with cork, which pro-
duces an even, white, level tint.
The last process is the selling of the teeth: that is,
every alternate tooth is to be bent a little on one side,
and the intermediate teeth, to an equal extent, on the
other side, so that each tooth may form an acute
angle with the surface ol' the saw. The object of this
setting is to prevent the teeth from becoming choked
up with sawdust, and also to give sufficient breadth
for the working of the saw, the lcerf or cut made by
it being thus wider than the thickness of the blade.
In setting a saw, the saw—maker fixes in the tail—vice
a small anvil or stake, Fig. 1917, with a rounded
edge, and the teeth of the saw being laid upon the
rounded edge of the stake, he strikes every alter-

nate tooth with a small hammer so as to bend it
round the curve: the face of the hammer is at
right angles to the handle, and sufliciently narrow
to strike only one tooth at a time. Half the teeth
having been bent in this way the saw is turned over,
and the alternate teeth are treated in a similar man—
ner. The amount of set is determined for the most
part by the curve of the stake. The saw-maker per-
forms the operation with great precision and rapidity;
but for amateurs, who have not acquired his skill,
saw-sci‘ pliers are provided, by which they can do the
work much more slowly, but with much less risk of
breaking off the teeth. The teeth are next filed up
sharp ; for which purpose the saw is placed in a vice,
between slips of wood or clamps of sheet-lead, in order
to prevent that unpleasant schreeching noise which
accompanies the action of the file when the saw is
not held securely. The saw is once more held over
the fire for the purpose of tempering it, and the thin
film of oxide is washed oil with very dilute hydro-
chloric acid, The saw is now ready for handling. The
handles are cut out of a plank of beech by means of a
hand-saw; then worked up with files and rasps, and
polished with a whale—fin and a bone burnisher. The
back plate, when required, is also fitted ; it is a piece
of iron folded together so as to form a groove, which
clasps the back of the saw like a spring.
Saws may be divided into two great classes, the
rectilinear and the circular ,' the former are generally
used by hand; the latter are always combined with
machinery. In the straight saw the thickness of the

blade is reduced by grinding from the teeth towards
the back: in the circular saw, the blade is usually
of the same thickness throughout: in the veneer saw,
however, it is thinned away at the edge.
The inclination of the face of the tooth is called
the pilot. In wheels and screws the pitch is the in—
terval from tooth to tooth: the saw-maker defines
this interval by the number of points to the inch, and
these may be 2, 3, a, 5, to 20; but where the inter-
vals between the points of the teeth are very wide,
as from % to 1% inch, they are said to be lzalf or one
and a quarter inch space. Some of the circular saws
are as coarse as 2 to 3 inches.
With respect to the forms of the teeth, Fig. 1919 6,
may be taken as the most simple, capable as they are
of being produced by angular notches filed with two
of the sides of an equilateral triangular file, so that the
points assume the same angle as the spaces, viz. 60°.1
This angle of 60° is variously placed: the teeth, in
a, are said to have an upright pitch, although, in fact,
there is no pitch; while the teeth in cl are said to be
flal, or to have a considerable pitch. Between these
two extremes the inclination or pitch is very various.
Wm. N/Wv
Wm 4%4/W
AMA/Vt W
Fig. 1918.
In general, the angles of the points of the teeth are
more acute the softer the material to be sawn.
Fig. 1918 a, is a common form of tooth, called the
peg-tooth, or the fleani-i‘oolli. This, as well as 5, is
used for cross-calling saws, or those which cut across
the fibre of the wood: the saw has a handle at each
end, and is worked by two or more men, as in cutting
down trees and dividing them when they have been
felled. Similar saws are used for cutting the soft
building stones when first got out of the quarry.
The gallezfalooil, j; is also used for cutting timber
across. 0 is the tooth in most general use 3 it is
known as the ordinary-pitch, or liancl-saic-iooi‘iz, and is
much used by cabinet-makers and joiners; also for
circular saws for fine work, such as veneer-saws, and
for many cross-cutting circular saws, and for saws
used for metal. In some cases the acute angular

(1) The angles of the faces and of the tops of the teeth are mea-
sured from the line running through the points of the teeth or the
edge of the saw. The angle of the point itself is found by sub-
tracting the angle of the back from that of the face of the tooth
or the less from the greater of the two numbers. In the illustra-
tions given the angles and spaces are as follows :—
ANGLES. SPACFS.
Face. Back.
Fig. 1918, a 110° .... .. 70° .... .. -j- to 1%
-— b 120 .... .. 60 .... .. .3. to 1%L
——- c 90 .... .. 30 -g_ to 1
—- d 75 .... .. l5 .... .. a}; to 2%
— e 90 .... .. 50 5‘; to 4
~'- f 90 .... .. 30 is! to 3*
SAW.
581
notch is not continued to an internal angle, as in e,
a form adopted in some mill-saws, both of ordinary
or perpendicular pitch, as well as for those of greater
pitch. This kind of tooth being more acute than 60°,
does not admit of being sharpened with the 3-square
or equilateral file, but with a thin flat file, with square
or round edges, called the mill-saw file. Angular
mill-saw teeth are more readily sharpened than the
pallet-teeth, f; so named from the large hollow or
gullet cut away in front of each tooth in continua-
tion of the face: they are also called betar-teet/z.
The gullet allows the tooth to be sharpened with a
round or half-round file, by which the face of the
tooth becomes concave when seen edgeways, and
acquires a thin and nearly knife-like edge. The
additional curvilinear space leaves more room for the
sawdust, and is less disposed to choke than the
angular notch. The gullet is sharpened with a round
or half-round file. In some cases each alternate
tooth is cut out, and the saw is then called slap-tooth.
Rectilinear saws admit of being arranged into three
groups. 1. taper-saws, which if long have a handle
at each end as in the pit saw and the erosseat-saw ;
but if short, or not over 30 inches in length, there is
only one handle, and that is placed at the wide end
as in the common land-saw, the rip-saw, Izalf-rz'p,
broken-space, panel-saw and fine-panel. Of these saws
the rip-saw has the coarsest teeth and of slight pitch;
the half-rip is a little finer, and both are used in
carpentry for ripping or cutting fir-timber rapidly
with the grain. The hand and fine-hand saws are
finer in the teeth, which are of ordinary pitch, and are
used for cutting mahogany and other hard woods
with the grain. The panel and fine panel saws are
still finer: their use in cutting out paaels for oak and
other wainscotting has given them their name.
The narrow taper saws used for cutting curves
and sweeps belong to this group. Such are the table
saw, and the compass or loe/e-saw, and the leey-lzole or
fiet-saw. Mr. Holtzapffel remarks that, “it would
be desirable, if in the narrow taper saws with only
one handle, we more frequently copied the Indian,
who prefers to reverse the position of the teeth so
that the blade may cut when pallecl towards him,
instead of in the tlzrast : this employs the instrument
in its strongest instead of its weakest direction, and
avoids the chance of injury. The inversion of the
teeth, which in India is almost universal, is with us
nearly limited to some few of the key-hole and prun-
ing saws.” 1
The pruning-saw has the hand-saw tooth of slight
pitch, and also double teeth when living timber is to
be cut. The saw is sometimes mounted at the end

(1) In Holtzapfi'el’s “ Mechanical Manipulation ” the 27th chapter
is devoted to the subject of “saws.” It occupies 134 pages and
is illustrated by 164 wood engravings. The subject is admirably
treated and well worthy the attention of the mechanical reader.
Those who have the opportunity of consulting it will also be
gratified with Mons. Emy’s “ Traité de 1’ Art de la Charpenterie,”
2 vols. 8vo.. Paris 1837, together with an Atlas of 135 large plates
in which are shown the various forms of tools, and the modes of
workmanship, essentially difi'erent from our own, which are in
common use on the continent.

of a light pole 41 to 6 feet long, so that the edge of
the blade may form an angle of about 150° with the
handle. It can then be used for branches 8 or 10
feet from the ground. Pruning saws are also mounted
in buck-horn handles like carving knives, and are also
made as clasp or pocket knifes.
II. The second group consists of parallel saws wit/z
tacks, or those which are stiffened by a rib placed on
the back of the saw and parallel with the teeth. The
blade is thin and the back is a piece of stout sheet
iron or brass folded together first at an angle between
top and bottom tools, and then closed with a hammer
upon a parallel plate thicker than the saw. The
inside of the groove is filed smooth, and the two
edges are then grasped in a tail vice and the ridge is
hammered to make the edges spring together. The
back is held upon the blade by the elasticity thus
imparted: the blade only extends about half way
down the groove. Back saws are used for accurate
work: the teaoa saw and the dovetail saw express by
their names the work for which they are used. The
eoazb-eattefs cloable saw is described under COMB.
III. Saws in this group are furnished with an
external frame for straining the saw blade in the
direction of its length, so as to keep it straight and
prevent buckling. The blades are made very thin,
and occasion but little labour and waste, and may be
used like the Indian saws by pulling the blades. In
the sawframes “there is a central rod or stretcher to
which are mortised two end pieces that have a slight
power of rotation on the stretcher; the end pieces are
at the one extremity variously adapted to receive the
saw, and at the other they have two hollows for a
coil of string in the midst of which is inserted a short
lever. On turning round this lever the coil of string
becomes twisted and shortened: it therefore draws
together those ends of the cross pieces to which it is
attached, whilst the opposite ends from separating,
strain the saw in a manner the most simple, yet effec-
tive. The tension of the blade is retained by allowing
the lever to rest in contact with the stretcher, as
represented Fig. 1920, but when the saw is not in
a ‘12




Fig. 1920.


use, the string is uncoiled one turn to relieve the
tension of the blade and frame, one or other of which
may be broken by an excessive twist of the string.”
This description, from Mr. Holtzapli'el’s work, may be
illustrated by the woocl-eatter’s saw, Fig. 1920, in
which “the end pieces are much curved, and one of
them extends beyond the blade which is embedded in
582
SAW.
two saw-kerfs and held by a wire at each end: the
blade is therefore always parallel with the frame of
the saw which is mostly used vertically. The end
piece alone is grasped at 9* and Z by the right and, left
hands respectively; the wood is laid in an X form
sawing horse and is sometimes held- by a chain and
lever, or less frequently in a strong pair of screw-
chops.”
The ivory saw, the smz‘flz’s flame-saw, and the side-
fmme-saw are small saws in iron frames, and tension
is given to the blade by a screw and nut. Piercing
and entering-saws are also fine and keen: the bulgi-
cuzfter’s-saw belongs to this class. [See BUHL-WORK,
Fig. 381.] . '
SAW-MILLS. The operation of sawing by hand is
simple but very laborious, and men must at an early
period have sought for‘ some meaps of setting
machinery to work for the purpose. According to
Beckmann1 saw-mills driven by water power; were
erected so early as the fourth century in Germany on
the small river Roer or Ituer. Saw mills do not
appear to have been common until about the four-
teenth and fifteenth centuries. After noticing. their
erection in several parts of Europe the learned writer
says :—“ In England saw-mills had at first the same
fate that printing had in Turkey, the ribbon-loom in,
the dominions of the church, and the crane at Stras-
burgh. When attempts were made to introduce them .
they were violently opposed, because it was appre—l
hended that the sawyers would be deprived by them '
of their means of getting a subsistence. For thisig
reason it was found necessary to abandon a saw—mill‘:
erected by a Dutchman near London in 1663; and i
in the year 17 00, when one Houghton laid before the ‘
nation the advantages of such a mill, he expressed '"
his apprehension that it might excite the rage of the
populace. What he dreaded was actually the case in
1767 or 1768, when an opulent timber merchant, by
the desire and approbation of the Society of Arts,
caused a saw-mill, driven by‘ wind, to ‘be erected at
Limehouse under the direction of James Stansfield,
who had learned in Holland and Norway the art of
constructing and managing machines of that kind. A
mob assembled and pulled the mill to pieces; but the ’
damage was made good by the nation, and some of‘
the rioters were punished. A new {mill was after-
wards erected, "which, was suffered to work without
molestation, and which gave occasionnto 'the erection
of others. It appears, however, that this was not the i
only mill of the kind then in Britain, for one driven
also by wind had been built at Leith in Scotland some
years beforef’ : _
The common saw-mill forcutting timber into planks
consists of a square wooden frame in which a number
of saws are stretched, which frame, by the motion of
a crank, rises and falls in another wooden frame se-.
cured to the foundation of the mill. The timber to
. be cut is placed upon a horizontal bed or carriage,
sliding upon the floor of the mill, and sufficiently nar-
row to pass through the inside of the vertical or

(1) In the “ History of Inventions,” is an interesting paper on
saw-mills, with some speculations on the origin of the saw.

moving saw-frame, and thus it carries the tree through
and subjects it to the action of the saw. The carriage
is provided with a rack, which is engaged by the teeth
of a pinion, and by this means the carriage is advanced
by turning the pinion by a large ratchet-wheel with
a click moved by levers connected with the saw-frame,
so arranged that when the saw-frame rises the click
slips over a certain number of teeth in the ratchet-
wheel, and when it descends to make the cut, the click
turns the ratchet-wheel round, and sends the wood
forward just ‘as much as the saw cuts during its dc-
scent. The trees are dragged up an inclined plane
through a door at one end of the mill, and being
placed upon the carriage, they pass through, and are
'divided by the saw into 2 or more pieces, which are
carried forward and passed out at a door on the oppo-
site side of the mill.
A saw-mill constructed by Mr. Hague, of Ratcliff,
is represented in the steel engraving. A A are timbers
built in the foundation of the mill, to which the cast-
iron framework 13 B is bolted by strong bolts and nuts
am. 0 o is a horizontal shaft with a hearing at each
end in the sides of the framework. To it are attached
the fast and loose pulley 1) E, over which the working
strap is passed; I? F is a fly-wheel; e e is the frame
in which the saws are fixed: it is guided in its verti-
cal motion by moving on square bars 6 6 attached to
a projected part of the cast-iron uprights or framing.
This method of guiding the saw-frame is attended
with very little friction, and any looseness from the
wear of the parts may be corrected by screwing up
the nuts -0 0. Friction rollers are sometimes employed
for diminishing the friction between the saw frame
and the channel in which it moves. The saws are
fixed and stretched in the frames by wedges, which
are driven above through mortices in the upper part
or bar of the saw. In this way a number of saws
may be fixed on the frame, and to keep the saws at
proper distances apart, and to prevent their tendency to
twist in the plane of their direction, pieces of wood of
the exact thickness of the planking are placed be—
tween the blades and secured by the pressure of the
side screws.
By Mr. Brunel’s method of fixing and tightening
saws, a number of saws can be quickly removed from
the frame and a new set of sharpened ones put in.
To each end of each s'aw pieces of metal in the form
of .hooks are riveted. The book at the lower end of
the saw falls into a recess in the lower cross bar of
the frame, and the upper hook is engaged with the
hook of ‘a shackle or .link which hangs upon the upper
cross bar, and 'has wedges through it by means of
which it can be drawn tight for the purpose of strain-
ing the saw. As the tension of the different saws is
uncertain when the wedges of the shackles are merely
driven in by a hammer, a steelyard is employed, which
not only shortens the time for driving up the wedges,
but shows the amount of tension given rto the saw.
It consists of a strong axle extended across the fixed
frame in which the saw-frame slides, and above the
top of this frame, from one side of this axle, a lever
proceeds with a weight attached to the end, and from















S A W.
583
the opposite side of the axle proceed two short levers
connected by links to a strong cross bar, situated just
over the upper cross bar of the saw-frame when at its
greatest point of elevation. This cross bar of the
steelyard has a link or shackle upon it which can be
united by a key with any of the shackles upon the
upper cross bar of the saw-frame, which shackles are
united by the hooks with the upper end of their re-
spective saws; and by this means the lever, with its
weight, becomes a steelyard to draw up any one of
the saws with a determinate force. In using this
apparatus, the band or strap of the crank shaft is cast
oil to stop the motion of the saw—frame, the crank is
turned round to elevate the frame to the highest point;
two wedges are then put in between the saw-frame
and a fixed part of the stationary frame, and this holds
the saw-frame while the steelyard is applied, other-
wise it would tend to strain the crank and crank-rod.
The sharp saws are now put into the saw—frame, by
booking them upon the lower cross bar and uniting
the hooks to the shackles on the upper cross bar, and
pieces of wood are put between the saws according
to the gage of the wood intended to be sawn, and
bound fast by screws. The loaded end of the steel-
yard is now lifted up by a rope passing over a pulley,
and the link upon the cross bar of the steelyard is
united with the shackle of one of the saws : then, by
allowing the steelyard to descend, it stretches the saw,
and the wedge being thrust in by hand as far as it
will go, thus retains the saw at the tension to which
the steelyard had stretched it. The shackle of the
steelyard is then disengaged from the saw, and re-
moved to the next, and thus in turn all the saws are
strained more equally than can be effected by simple
wedges.
Returning now to the steel engraving, I I are cast
uprights, bolted firmly to the floor of the mill, which
is not shown in order not to interfere with the me-
chanism. These uprights carry at their upper part
horizontal rollers, upon which the timber is moved
while passing through the mill. The timber is fast-
ened at one end to a carriage attached to the rack L,
and at the other to a carriage which can be adjusted
according to the length of the timber to be cut. M is
a rack by which the timber is moved on during the
action of the saw by the following contrivance. N is
a horizontal lever turning upon the point N, and
receives a slight reciprocating motion from an eccen-
tric 9 upon the crank shaft during the stroke of the
saw, but in a reverse direction, so that while the saw
descends, the end of the lever rises: it is a small arm
attached to the lever in such a way as to engage the
teeth of a large ratchet-wheel 0 0 while the motion is
upwards, but in its descent simply passes over them
without giving motion to the wheel. It has a small
counterweight a, which causes the end of the arm to
press gently against the teeth of the ratchet-wheel m,
in order that in its return it may not fail to engage
them. It will then be readily seen, that during the
descent of the saw, which is the time its action takes
place, the lever N, by means of the eccentric, is moving
the ratchet-wheel round, from which, by a small pinion

p upon its axle, which engages the teeth of the rack
_ M M, the carriage and timber are moved gently forwards
towards the saw.1 The turning point of the lever N N
can be adjusted to any part of it within the point a’
where the eccentric rod is fastened, so that any de-
gree of motion can be given to the timber according
to the nature of the wood to be cut. 1? P is a guide
for the timber while passing the saw-frame: it causes
the timber to move in a direction parallel to the mo-
tion of the saw. The timber is pressed against the
guide by means of alever, one end of which is connected
with a weight over a pulley, and the other to a roller,
which is pressed by means of the weight against the
timber, and keeps it in its proper position with respect
to the saw. When the timber has passed the saw, the
carriage is returned by means of a handle at upon the
spindle of the ratchet-wheel and pinion, which is
worked by a man; the click being of course thrown
up clear of the teeth to allow of its motion in a reverse
direction. In some mills this is effected by the en-
gine ; but a man can easily run it back in less than
a minute.
Two deals are usually sawn at one time, so that the
parts described are in duplicate, and in the engraving
one deal is removed in order the better to show the
mechanism. Each deal is usually cut into 3 boards,
in which case two saws are arranged on each side of
the frame. In some cases as many as 11 thin saws
or Webs are used, thus producing from each deal 12
thin boards or leaves.
The single saw-frame makes from 100 to 120
strokes per minute, each stroke being 18 to 20 inches
long, and two 12-feet deals are cut in from 5 to 10
minutes. For hard deals the saws require to be
sharpened about every tenth roaacl or journey; and
about every twentieth round for fine. The frames
are also made double so as to cut 4: deals at a time,
in which case a double crank is used, so arranged,
that while the saws in one frame are descending
those in the other are ascending. The effect of this
arrangement is to diminish vibration and to allow the
velocity to be increased to 160 to 200 strokes per
minute: but there is not much gain on this account,
since a longer time is required for fixing and adjusting.
CIRCULAR saws. Various applications of the cir-
cular saw are given in the account of Brunel’s block
machinery [See BLOCK], and also in the notice of the
sash-bar machine. [See INTRODUCTORY ESSAY, Fig.
xl] We shall also have to describe it under VENEER-
me. The applications of the circular saw are, however,
so numerous that it would not be possible to give
even a list of them within the remainder of our limits.2
There is considerable doubt as to the date of
the introduction of the circular saw 3 [See IN'rno-
DUCTORY ESSAY, p. cxlii] Circular saws for cutting
the teeth of water and clock wheels have been in use

(I ) In the plank-frame invented by Mr. Benjamin Hick, of Bolton,
there is no long rack; but each deal is grasped between two
grooved feeding~rollers, the one fixed to the framing of the ma-
chine, the other pressed up by a loaded lever, and moved a single
step at a time by a ratchet-wheel.
(2) The reader interested in the subject is referred to the chapter
in Holtzapfi‘el’s “ Mechanical Manipulation,” already quoted.
5841
SAW-SCAFFOLDING—SCALE.
since the time of Dr. Hooke: and the application of
the wood-cutter’s saw in the form of a revolving disc
has been by some writers claimed for General Bentham .
In 1805, Brunel took out a patent for sawing timber
by means of a large circular saw, composed of several
pieces fitted together by screwing them to a large
flange turned perfectly true and forming part of the
axle of the saw.
The method of constructing, sharpening and setting
circular saws is very similar to that employed for
rectilinear saws. In the planishing or hammering,
the cutting edge of both kinds of saw, but especially
the circular, should be made denser than the other
parts: it should be made light or small as it is called,
and the amount of expansion produced by friction will
then enlarge the edge so as to bring the saw into a
state of uniform tension. If the edge of the saw be
as wide as the other parts, the heat excited by friction
when at work will cause it to vibrate from side to
side, producing an irregular cut and a flanking whip-
like noise, arising from the buckled parts of the plate
in passing through the saW-kerf. The teeth of cir-
cular saws are in general more distant, more inclined
and more set, than those of rectilinear saws. They
are more distant on account of the greater velocity
given to the saw, whereby the teeth follow in such
rapid succession that the effect is almost continuous.
They are more inclined because such teeth out more
keenly, and the extra power required to work them is
readily applied. The harder the wood, the smaller
and more upright should be the teeth, and the less
the velocity of the saw. The teeth are more set in
order to produce a wider kerf, since the large circular
plate cannot be made so true, nor keep so true as the
narrow straight blade. The setting must be very
uniform, as one tooth projecting beyond the general
line will score or scratch the work. “ It is generally
politic to use for any given work a saw of as small
diameter as circumstances will fairly allow, as the
resistance, the surface friction, and also the waste
from the thickness, rapidly increase with the diameter
of the saw. But on the other hand if the saw is so
small as to be nearly or quite buried in the work, the
saw-plate becomes heated, the free escape of the dust
is prevented, and the rapidity of the sawing is
diminished.” As a general rule the diameter of the
saw .9 Fig. 1920, should beIabOut At times the average
thickness of the wood w; and the flange on the
w .
'1' r , >
if’, __ l‘
g w Q
s a
is ..
4b.
a In"
RWMMJ
Fig. 1920.
t?
spindle should be as nearly as possible flush with the
platform or saw-table ~l If.
In cutting with the grain, the teeth of the saw
should be coarse and inclined, and the speed moderate,
so as to remove shreds rather than sawdust. In

cutting across the grain the teeth should be finer and
more upright, and the velocity greater.
CnOwN saws. The lrepln'ne saw of the surgeon,
which is said to have been known in the time of
Hippocrates, has given rise to a large number of
similar saws of various sizes, and under different
names, such as nnnnlnr, curvilinear, drum and was/zing-
tnb saws. Small saws of this kind, mounted upon
the lathe, are used for cutting out discs of metal and
wood. In the block machinery at Portsmouth the
sheaves are cut out by means of the crown saw [See
BLOCK]. At some saw mills, crown saws 5 feet in
diameter and 15 inches deep are used: they are con-
structed of 3 or 4t pieces of steel riveted to the out—
side of a strong ring which is fixed to the surface.-
chuck of a kind of lathe mandrel, and the work is
grasped in a slide rest which traverses within the
saw parallel with its axis. Large saws are used for
cutting out the felloes of wheels and similar curved
works; saws about 2 feet in diameter are used for
cutting the round backs of brushes, the sloping hollow
backs of chairs, &c. The edges of the staves of casks
have also been cut by these saws before the staves
were bent.
SCAFFOLDING, a temporary erection of timber
for the purpose of supporting the workmen and the
materials during the erection of a building. The
bricklayer’s scafl’old is formed of fir poles, each 40 or
50 feet in length, and 6 or 7 inches in diameter at the
butt ends which are securely fixed in the ground.
Additional length is gained by lashing the top and
butt of two poles together, and tightening the lashing
by driving in wedges. These standards are united
by means of horizontal poles placed parallel to the
walls and called ledgers : they serve to support cross
pieces called pnllogs, made of birch, each about 6 feet
in length, one end resting in the wall and the other
on a ledger. The scaffold boards are supported by the
putlogs: these boards are hooped at the end to
prevent them from splitting.
As putlog holes cannot be allowed in masonry, the
mason’s scaffold is formed with two rows of standards
so as not to require the support of the walls. But it
is now usual in large works to form the scaffolding of
square timbers connected by bolts and dogirons. The
materials are hoisted by means of a travelling crane,
consisting of a double travelling carriage running on
a tram-way formed 011 stout sills formed on the top
of two parallel rows of standards. The crab~winch
is placed on the upper carriage, and by the double
motion of the two carriages can be readily brought
over any part of the work situated between the two
rows of standards. [See Cnanu]
The scaffold or eenz‘erz'ng used in building arches is
noticed under Bnincn, Section III.
SCAGLIOLA—See Mon'rnns and CEnEcNTs——
STONE, ARTIFICIAL.
SCALE, a line drawn upon wood, ivory, &c., and
divided into parts, the lengths of which may be taken
off by the compasses and transferred to paper. The
usual method of forming scales is by copying a care—
fully prepared original. See GRADUATION.
SGANTLING-——-SCHIST-—SORATGH-BRU ‘SH—SCREW.
SCANTLING, a term applied to small timbers,
such as the quartering for a partition, rafters, purlines,
&c. All quartering or squared timber under 5 inches
square is so called: the term is also used to express
the transverse dimensions of a piece of timber.
SGARFING—See Canrnn'rnr.
SGHEELE’S GREEN—See Ansnnrc. The apple-
green pigment, so called, is prepared by dissolving
2 parts of sulphate of copper in 4:41 of hot water, and
gradually adding to it a solution of 2 parts of carbo-
nate of potash and 1 of arsenious acid in 1M: of hot
water, the whole to be well stirred during the mix-
ture. The precipitate is to be washed, and dried at
212°.
SGHIST, a term sometimes applied to slate, but
more properly limited to those rocks which do not
admit of indefinite splitting like slate, but only of
a less perfect separation into layers or laminae; such
are gneiss, mica-schist, chlorite-schist, talcose-schist,
&c. The schists are fundamentally silicates of alu-
mina; but they are so much mixed with such mine-
rals as sand, mica, chlorite, talc, hornblende, actino-
lite, &c., as to form distinct varieties.
SGHWEINFURTH GREEN, a similar precipitate
to that described as Scunnnn’s Gnnrn, but of a finer
colour. 50 lbs. of sulphate of copper and 10 of lime
are dissolved in 20 gallons of vinegar, and a boiling
hot solution of arsenious acid is quickly stirred into
it: the precipitate is to be dried and reduced to a
fine powder. Both this and Scheele’s green are very
poisonous : they have nevertheless been employed
in colouring sweetmeats.
SGISSORS. See Gnrtnnr.
SCRATCH—BRUSH, a cylindrical bundle of fine
steel or brass wire, bound tightly in the centre with
the ends projecting at both extremities, so as to form
a stiff brush for cleaning and scratching metals pre-
paratory to gilding and silvering. These brushes are
sometimes made in the form of wheels, in which case
the ends of the wires are a little curved, to prevent
them from meeting the work too abruptly.
SETTING, or Razons, Saws, 85c. See GUrLnnY
-—-SAW.
SCREW. Screws are of two kinds—concert’, also
called external, or male, and concave, also called inter-
nal or female. The first kind consists of a solid
cylinder of wood or metal, on the surface of which
is a projecting rib, fillet, or t/zreacl, passing spirally
round so as to make equal angles with lines parallel
to the axis of the cylinder. The second kind of
screw consists of a cylindrical perforation through a
solid block, the surface of the perforation bearing a
spiral groove, corresponding to the thread on the solid
cylinder, which fits it, or to which it is adapted. ,
The screw is usually regarded as a continuous
circular wedge. If a piece of paper in the form of
a wedge be regularly wrapped round a wooden cylin-
der, the edge of the paper will represent the line or
thread of the screw» The interval between the threads
will vary with the angle of the wedge, and the screw
will be coarse or fine according as this angle is large
or small. The screw will be a rig/zt-liancl or a left-liand

585
screw according as the wedge is wound upon the
cylinder to the right hand or to the left. Double
triple, or guarlruple screws are those which have
a double, triple, or quadruple thread, such, for ex-
ample, as would be formed by placing 2, 3, or ‘.lé
strings in contact, and coiling them as a flat band
round the cylinder. The screw may also vary in sec-
tion, that is, the section of the worm or thread may be
angular, square, rouncl, &c. The screw may also vary
in diameter. The degree of accuracy with which the
screw is cut depends upon the purpose to which it is
to be applied. Binding or attaclzment screws, used
for connecting together the various parts of an ob-
ject, do not require any especial care in their manu~
facture. Regulating screws, for guiding the slides and
moving parts of machinery,-—the screws of presses,
for example, require a much higher degree of accu-
racy. The highest degree of excellence within the
reach of the mechanician is required in nzicronzetrical
screws for graduating the right lines and circles and
the scales of astronomical and mathematical instru-
ments. [See Gnnnunrrou]
Considering the screw to consist of two parts, the
external and the internal, it is easy to see how the pro-
duction of the one may lead to the production of the
other. Thus, by filing two or more flat faces 011 the
external screw, the angles left form a series of cutters;
the screw is, in fact, converted into a tap, by which
internal screws of corresponding size and form can
be produced. One of these hollow screws becomes
the means of regenerating any number of copies of
the original external screw. The art, however, of
originating screws, or forming the original screw from
which the tap is cut is a somewhat difficult one, and
the more so in proportion to the accuracy required.
In the early attempts a wedge of paper was cemented
to an iron cylinder, and the spiral line was cut
through with a knife or thin edged file, and the
groove was gradually enlarged until the screw was
formed. After the invention of the turning lathe a
pointed turning tool was used to assist the file. Before
the introduction of the screw-cutting lathe, the follow-
ing method of originating a screw, by a workman
named Anthony Robinson, was adopted at the Soho
works :——“ The screw was 7 feet long, 6 inches
diameter, and of a square triple thread: after the
screw was accurately turned as a cylinder, the paper
was cut parallel, exactly to meet around the same,
and was removed and marked in ink with parallel
obliquelines, representing the margins of the threads;
and having been replaced on the cylinder, the lines
were prieked through with a centre-punch. The
paper was again removed, the dots were connected
by fine lines cut in with a file, the spaces were then
cut out with a chisel and hammer, and smoothed
with a. file to a sufficient extent to serve as a lead or
guide. The partly-formed screw was next tempo-
porarily suspended in the centre of a cast-iron tube
or box, strongly fixed against a horizontal beam, and
melted lead mixed with tin was poured into the box,
to convert it into a guide-nut: it then only remained
to complete the thread by means of cutters fixed
586
SCREW.
against the box or nut, but with the power of adjust-
ment, in fact, in a kind of slide rest, the screw being
handed round by levers?"
Another method of originating ascrew is to wrap
a small wire in close coils round a larger wire, and to
take an impression thereof between two pieces of
hard wood. The hollow or counterpart thread thus
indented serves as a guide in cutting the screw. Mr.
Mallett, of Dublin, described the following plan in
the Mechanics’ Magazine for January, 1844! :—'--“ Two
straight edges of equal length and width, and about
_ g-ths of an inch in thickness each, are to be secured
on a table, parallel to each other, standing on their‘
edges, and distant from each other by nearly the
length of the cylinder upon which the spiral is to be
marked. Between these there is also to be secured
in a diagonal direction, stretching from one to the
other, a third straight edge, formed of two slips of
deal glued together, with a slip of straight thick
Bristol board between them projecting gth inch at
one edge. The entire height of the diagonal straight
edge, when standing on the table, must be a shade
more than that of the two other straight edges. The
three pieces being then thus arranged, the edge of
Bristol board is charged with printers’ ink. Then,
on causing the cylinder to roll over the edges of the
two parallel straight edges in the direction of their
length, the diagonal slip of inked Bristol board will
trace a spiral upon the surface of the cylinder with
very considerable accuracy.” By substituting a curved
edge for the inclined straight edge variable screws
will be obtained.
Screws are also originated by indenting a smooth
cylinder with a sharp—edged cutter placed across it at
the required angle, the surface or rolling contact pro-
ducing the rotation and traverse of the cylinder.
“ In the most simple application of this method, a
deep groove is made along a piece of board, in which
a straight wire is buried a little beneath the surface;
a second groove is made nearly at right angles across
the first, exactly to fit the cutter, which is just like
a table-knife, and is placed at the angle required in
the screw. The cutter, when slid over the wire, in-
dents it, carries it round, and traverses it endways in
the path of a screw; a helical line is thus obtained,‘
which, by cautious management, may be perfected
into a screw sufiiciently good for many purposes.
The late Mr. Henry Maudslay employed a cutter
upon cylinders of wood, ‘tin, brass, iron, and other
materials, mounted to revolve between cutters in a
triangular bar lathe; the knife was hollowed to fit the
cylinder, and fixed at the required angle on a block
adapted to slide upon the bar; the oblique incision
carried the knife along the revolving cylinder. Some
hundreds of ' screws were thus made, and their agree-
ment with one another was in many instances quite
remarkable; on the whole, he gave the preference to
this mode of originating screws.”-2 The screw is also

. (1) Gill’s Technological Repository, vol. vi. Mr. Holtzapifel
thinks it probable that a gun~metal nut was cast upon this screw,
for use, after the screw was finished.
(2) Holtzapfi‘el.
“ Mechanical Manipulation,” :vol. -ii. The

‘originated by traversing the tool in a right line along
a plain revolving cylinder. Sometimes the tool has
many points, and is guided by the hand alone : at other
times the tool has but one single point, and is guided
mechanically, as will be explained hereafter in the.
screw-cutting engine. '
The external screws which are used for fastening
pieces of wood, or wood and metal together, are called
iccocl- screws, and in Scotland screw-nails. The blanks for
these screws were formerly forged by the nail-makers,
they being nearly the same as countersunk clout
nails, [see NAIL, Fig. 1e89, No. 5], except that the
ends are not pointed. The blanks were next made out
of round rolled iron out to the required lengths ; the
heads being formed by pinching them while red-hot
between a pair of dies, and the threads were cut by
means of a file. But the method of making screws
now most commonly adopted is that witnessed by the
Editor in a factory at Birmingham, and described in
his work on the “ Useful Arts and Manufactures of
Great Britain,” already referred to. In the first place,
a coil of wire fit for making screws is arranged so
that it can be drawn into a machine as it is wanted;
pieces of,the proper length are cut off, and one end of
each is struck up to form the head, and the blanks
thus produced are then turned out into a box. By a
second operation, the blanks are taken separately and
placed in a lathe, where the heads and necks are pro—
perly shaped, by turning and cutting away superfluous
metal. Thirdly, the notch or nick in the head of the
screw for receiving the screw-driver is cut by means
of a circular saw; the woman puts each screw into
a kind of clasp, which holds it firmly, and then, by
means of a lever, raises it to the cutter; the nick is
formed in an instant,——the clasp is opened, the blank
falls out, and another is inserted in its place, with
great quickness. The teeth of the circular saws used
in this operation, require filing up after every half-
hour’s work: for which purpose they are taken out,
softened by heating and slowly cooling, then filed and
sharpened, next hardened by heating and suddenly
cooling; after which they are again fit for use.
Fourthly, the blanks are ready for worming, as the
operation of cutting the thread is called. This is
done in a lathe; and as the blank requires to be held
‘therein very steadily, the nick just formed is made to
assist in doing so. The arrangement is shown in
Fig. 1921:~—A steel spindle or mandril revolves be-


- Fig. 1921.
tween collars in two uprights, by the motion of a
strap passing round the pulley, f: l is a loose pulley
to carry the strap when it is required to stop the
machine. At 5 is an iron box made to hold firmly

Chapter on the Screw in this work is of great value; it extends
beyond 100 pages, andjs illustrated by 109 wood engravings.- -
SCREW.
587'
the pattern or regulating screw, 2. This screw is
5 or 6 inches in length, and is an exact pattern of the
thread of the screw to be cut, so that a fresh pattern
or regulating screw is required for every variety of
screw. The screw to be cut is fixed in an iron
chuck or holder 0, (also shown separately in Fig.
1922,) and is held firmly by a kind of hasp, the nick
of the screw resting against a chisel spike, and the


Fig. 1922.
shank projecting. The cutters are arranged in the
frames at is: and are shown on a larger scale in the
following figure. These frames move on joint pins,


and by the operation of the lever the cutters are made
to act upon the shank of the screw, and to exert a
greater or less degree of pressure, according to cir-
cumstances. There is also a lever which causes cer
tain directing points, resembling the cutters, to close
upon the regulating screw 1’, and the two levers being
connected by a horizontal bar, can be depressed or
raised together, and the cutters and directors applied
at the same moment. In this way the inclination of
the thread is determined by the pattern screw, and its
shape by the form and position of the cutters.
This arrangement being understood, the order of
proceeding is as follows :—--The workwoman fixes a
blank in the chuck; she next transfers the strap from
the loose to the fixed pulley, thereby causing the
chuck to revolve; she then depresses the levers, and
the guides, acting upon the regulator screw from
behind, cause the chuck to move forward and force
the shank of the blank screw between the cutters,
which turn out a shaving of metal, leaving a sharp
thread or worm. The heat occasioned by this opera-
tion would soon destroy the temper of the steel cut-
ters were they not kept cool; for this purpose, while
the woman holds the lever down with one hand, she
takes up with the other a piece of wood, dips it in
water, and applies it to the tools. When the thread
is traced far enough, the levers are raised, the chuck
falls back, and the screw is'released. Another screw
is inserted in its place, and thus the cutting or tap~
ping proceeds.
Screws are also cut by dies instead of cutters.
The dies are arranged on a frame, and are opened and

shut by a right and left-handed screw. As the dies
regulate the size of the thread, there is no pattern
screw, and of course the dies require to be changed
for every variety of screw intended to be out. Mr.
Ryland’s gimblet-pointed screws are thus made. This
screw» enters the wood easily and retains its hold
firmly, and it is not liable to break where the thread
ends, which the common screw will often do, espe-
cially in hard wood.
Mr. Nettlefold’s patent screws are also made on
a similar principle. In them great attention is paid
to the thread, the upper side of which is very flat or
inclined, which causes a great resistance to its being
forcibly pulled out of the wood; while the under side
is considerably inclined, which enables it to go into the
wood with great ease, and rendering it unnecessary,
in soft elastic woods, to bore a hole for its reception.
The form of this screw, and its action upon the wood,
will be better understood from the following figures,


Fig. 1926.
Fig. 1925.
Fig. 1924.
in which Fig. 1924, represents the screw; Fig. 1925,
the mould made by it in wood; and Fig. 1926 is a
section of the common form of screw, in which the
worm is shallow and imperfect. “ The chief defects
of common wood screws, besides bad threads, are the
having, at the termination of the worm, a projecting
bur, which is apt to tear away the wood before it,
and leave little or no solid matter for the screw
to hold by; the nicks in the- heads being too shal—
low, or highest in the middle, preventing the screw—
driver from taking an eificient holdto turn them in
and on .”
Screw bolts and other screws for working in metal
are cut by a die resembling a common iron nut; it is
formed of well-tempered steel in two parts, which are
fixed in an iron box or die-stock, with two long handles
or levers, as in Fig. 1927, and there is also a set screw,
5, by means of which the 2 halves of the die may be
brought nearer together or removed from each other.
The blank or iron pin on which the screw is to be'cut,
having been turned to the proper size is introduced
by its narrow extremity into the dies, which are then
closed so as to grip the pin with tolerable force. The
pin is set in a vice, and the die is worked round upon
the pin by means of the two handles, and when a toler~
ably good impression of the thread is made upon the
pin the two halves of the die are set closer together,
and the operation is repeated whereby the thread is
more defined, and it is cut deeper by setting the dies
still more closely together. In such a case the worm
is not formed by merely cutting away the metal, but
partly by compressing it and squeezing it up, as it
were, into the thread. In cutting such a thread by
machinery the dies are in 4 pieces, the die-frame is
fixed and the bolt or screw pin is made to revolve.
588
SCREW.
The die-stocks in common use are known as doutle
c/zamfiared and single chant/‘bred. In the former about
one-third of the length of the chamfer is filed away at
one end for the removal of the dies laterally, and one
at a time, and the aperture is about as long as 3 of
the dies. In the single chamfered die-stock, the
aperture is about as long as 2 of the dies, and these
are removed by first taking off the side plate 1?,
Fig. 1927, which is either attached by its chamfered
edges as a slide, or by 4! screws, which when loosened
allow the plate to be slid endways, when the screws
escape from the grooves at ,9’,
and the screw heads from the
holes it. The single chamfered





. ....... ii
a s /’ est
Fig. 1927.

die-stock is preferred for large threads. The form
of the die-stock is liable to much variation, but this
is not of great importance provided the dies are ac-
curately fitted. “ In general only two dies are used,
the inner surface of each of which includes from the
third to nearly the half of a circle, and a notch is
made at the central part of each die, so that the pair
of dies present 41 arcs and 8 series of cutting points
or edges, 41 of which operate when the dies are moved



in the one direction, and the other 4.‘ when the mo-
tion is reversed; that is, when the curves of the die
. _ and screw are alike.” The
' m most usual form of dies is
l I ‘» shown in Fig. 1028, but as
"1 Mr. Holtzapffel remarks,
l’ M “ if every measure be taken
Fig 1928 at the mean as in this figure,
' ' the tool possesses a fair
average serviceable quality; that is, the dies should
be cut over an original tap of medium dimensions,
namely, one depth larger than the screw.”
Small metal screws are cut bya steel tap-plate or
screw-plate, Fig. 1929, wormed and notched, but fur-
nished with several holes varying slightly in size, and
the worm is formed progressively by using holes
gradually diminishing in size. From 2 to 6‘ holes are




flags‘??? alarms‘
iii a!” New”
"-
f
Fig. 1929.


. intended for each thread, and are arranged in groups
for the purpose as indicated by the short lines shown
in the figure. The cutting edges are formed by
making 2 or 3 small holes, and connecting them by
the lateral cuts of a thin saw. In making the screw
‘the wire should be fixed in a vice, the end tapered
off, and after being moistened with oil screwed into
the holes of the plate in succession. Although the
screw plate is sometimes used for common screws as
large as from if; to {2; inch diameter, it is better to use

die-stocks for all screws exceeding about TIB- inch
diameter. .
In cutting large screws, especially when the thread
is square, a steel cutter may be used with the die.
In cutting long screws in wood a steel cutter is fixed
in the female screw or screw-60:2,", as it is called, shown
in section Fig. 1930, and in plan Fig. 1931, through
the line a, and is thus described by Mr. Holtzapffel :—
“ It consists of two pieces of
wood, accurately attached by w .l
two steady pins and two 0
screws, so as to admit of
separation and exact replace-
ment: the ends of the thicker
pieces are frequently formed
into handles by which the instrument is worked.
A perforation is made through the two pieces of




Fig. 1030.




wood; the hole in the thinner piece is cylindrical,
and exactly agrees with the external diameter of
the screw or of the prepared cylinder; and the hole
in the thicker piece is screwed with the same tap
that is used for the internal screws or nuts. The
cutter or V has a thin cutting edge sloped exter-
nally to the angle of the thread, usually about 60°,
and thinned internally by a notch made with a tri-
angular file; the cutter is inlaid in the thicker
piece of wood and fastened by a hook-form screwbolt
and nut. In placing the cutter form different con-
ditions require strict attention. Its angular ridge
should lie as a tangent to the inner circle; its edge
should be sharpened on the dotted line b, or at an
angle of about 100° with the back ; its point should
exactly intersect the ridge of the thread, in the box;
and it should lie precisely at the rake or angle of the
thread, for which purpose it is inlaid deeper at its
blunt extremity. The piece of wood for the screw is
turned cylindrical and a little pointed: it is then
twisted into the screw box, the cutter makes a notch
which catches upon the ridge of the wooden worm
M
_----_.<-
l \.
Fig. 1932.
immediately behind the cutter, and this carries the
Work forward exactly at the rate of the thread. The
whole of the material is removed at one cut and
the shavings make their escape at the aperture or
mouth m.” The cutter is shown in Fig. 1932.
Screws of half an inch diameter and upwards are
fixed in the vice and the .screw box is handed round
like the diestock: but for large screws exceeding 2
or 3 inches in diameter, two of the V’s or cutters are
placed in the box so as to divide thework and lessen
the risk of breaking the keen edge of the cutter. The
SCREW.
589
screw box is used for wooden screws of 41, 6 and 8
inches diameter, but these large screws are now seldom
made, metal screws having taken their place.
A steel tap is used for cutting interior screws, as
already noticed. This tap is commonlyr a screw with
a considerable portion of the worm removed by filing
two or more flat faces along its whole length, the
angles left by the operation forming a series of obtuse
cutters. The tap is made somewhat conical in order
to enter the hole with facility and cut the worm
gradually. A tap is shown in 3 views in Fig. 1933.
Two taps are in some cases used, only the first of
which is tapered. The head of the tap is square, for
Fig. 1933. I
fitting into the middle of a long handle or tap-wrench
which is used for working it into the nut. The taps
for cutting screws in wood are usually fluted at the
ide to allow the cuttings to escape.
The simplest form of tap is produced by filing 4;
planes upon the screw, as in Fig. 18341, a; but the
edges thus produced are very obtuse, and form the
thread rather by raising or burring up the metal than
by cutting. A better form for cutting is obtained
by filing only 3 planes on the screw as in Z), but even
then the angle is as great as 120°. Taps of very
small size cannot well be formed of a more favour-
able section 5 but for general purposes the best angle
for the edges of screw taps and dies is the radial
line or an angle of 90°. Sir John Robison obtained
such an angle in his half round tap 0, and he states
that such a tap “ will cut a full clear thread, even if
it be made of a sharp pitch, without making up any
part of it by the burr, as is almost universally the
case when blunt edged or grooved taps are used.”
Mr. Holtzapffel remarks that when two-thirds of the
circle are allowed to remain as in (Z, this, “although
somewhat less penetrative than the last, is also less
liable to displacement with the tap wrench. It is




Fig. 1934.
much more usual to employ 3 radial cutting edges
instead of one only; and as in the best forms of taps,
they are only required to cut in one direction, or
when they are screwed into the nut, the other edges
are then chamfered to make room for the shavings,
thereby giving the tap a section somewhat like that of
a ratchet wheel, with either 3, 4: or 5 teeth,” as in
e and y. “ It is more common, however, to file up
the side of the tap or to cut by machinery 3 concave
or elliptical flutes as inf; this form sufiiciently ap-
proximates to the desideratum of the radial cutting
edges, it allows plenty of room for the shavings, and
is easily wiped out. What is of equal or greater im-
portance, it presents a symmetrical figure, little liable
either to accident in the hardening, of distortion from
unequal section as in c and I], or of cracking from in-

ternal angles as in a? and 6.” Mr. R. Jones has con-
trived a tap in which a steel cutter can be inserted as
shown in g: the cutter is made to project a little, so
that the tap follows it without difficulty. Mr. Gill
has described a tap for cutting a square threaded
screw: it consists of a hollow steel screw with a
hole drilled obliquely from the front end of the thread
to the hole in the centre of the tap: the edges of
this oblique hole are sharp, and cut their way through
the wood, while the hole forms a passage for the
escape of the shavings. Mr. Siebe’s tap for cutting
right hand or left hand internal screws in wood,
according to the direction in which it is turned, is re-
presented in Figs. 1935, 1936. The tap is formed by


Fig. 1935.
Fig, 1936.
turning a wooden screw of the required size, cutting
a longitudinal slit along its centre, and inserting a
plate of steel of the length and breadth of the screw:
the edges of this plate are now filed into notches
corresponding with the worm: the plate is then re-
moved and the wooden thread is turned away, leaving
the wood in the form of a plain cylinder. The steel
plate is then reinserted and firmly secured, as shown
in the figures, which give_ a side and an end view of
the tap. The steel plate is made to taper a little, so
as to ensure a gradual cutting action. A groove cut
on each side of the plate, affords a channel for the
escape of the turnings; the upper end of the cylinder
is made square for the insertion of the wrench. Such
a tap may also be formed without the assistance of
the worm on the stock, simply by notching the steel
plate, taking care that a tooth 011 one side shall coin-
cide with a hollow on the other. Mr. Siebe proposes
similar taps with only two cutting edges, for cutting
screws in metal.1
SCREW-CUTTING ENGINE. In the method of cutting
screws by the lathe as already described, the pattern
screw regulates the pitch of the thread, and screws of
difi‘erent make require each its own pattern. In the
Woolwich Dockyard is an engine for cutting large
screws accurately to any required pitch, from one
pattern. This engine is represented in elevation and
plan in the steel engraving.2 A B, Fig. 1, is one side
of a cast-iron lathe-bed, both sides of which are re-
presented in Fig. 2. P Q are two cast-iron puppets.
c D an axle turning on a point at 0, its end being
countersunk to receive the point, the other end bear~
ing on a slightly conical collar in the puppet Q. The
2 bevelled wheels ww’ fit one part of the axle, and
either of them may be thrown in or out of gear with
the other bevelled wheel W”, Fig. 2, which is turned
by the steam-engine shaft. On the side of the bed
are 2 standards s s, in which the screws 88 turn in

(1) Transactions of the Society of Arts, vol. xli.
(2) We are indebted to the volume on “ Manufactures,” in the
Encyclopaedia Metropolitana, for the drawings and dESCI'lptiOIIS or
this engine.
"5'90
SCREW.
collars, ‘both screws being seen in Fig. 2. n is a slid-
ing frame with a nut on each side, through which the
screws ss pass, so that as the screws revolve, this
sliding frame is carried from one end of the bed to the
other, and in this frame is fixed the tool for cutting
the threads of the screw. The cutter is secured in
its proper position by means of plates and nuts,
Fig. 9; Another cutter‘may belfixed on the opposite
side, so that one cuttertmay act ‘while the slide r is
passing from A towards B, and the other as it re—
turns from is to n. This plan, however, does not
produce very good results in practice, so that 'one
cutter only is employed, and the carriage returns free.
The ‘cutter is adjusted to its ‘proper place by the
screwandlever cal. ‘,1 fr vis a sliding puppet carrying
the 'back centre: this‘ .pu‘pf'pe't :may'ibe placed in any
part of the "bed, and ‘there *screwed fast, while any
small adjustment for distance may be made by the
screw c, Fig. 2. The bolt or cylinder on which the
screw is to be formed being turned perfectly true to
two centres, one at each end; this.‘ is applied to the
points in the mandrel and back centre, and a proper '
The
degree of contact is attained by the screw G.
end of the cylinder next f to. the mandrel D is
properly secured’: an iron chuck is ‘placed on
the mandrel, and rotation is given to the cy-
linder by means of the driver,‘ and in this
form it may be used for any purpose in which
a powerful lathe is required. But for cutting
screws, a wheel a: is fixed on the mandrel,
and 2 equal wheels on the ends of the screws
as, so‘ that ‘while the cylinder revolves by

thread is first cut, and then the driver is applied to
a hole in the iron chuck directly opposite to its first
position, by which means a semi-rotation is given to
the new screw without producing any motion in the
cutting frame, and consequently the cutter is now
applied to a point midway between the two former
threads, when by the same process as before this
intermediate thread may be formed. If a triple
thread be required, the ».driver is applied to a hole
.in the chuck, which is distant from its original posi-
tion one-third of a circumference, and then again to
another at two-thirds the distance, and in a similar
manner any number of threads may be formed.
The apparatus ‘for cutting the nut consists of a re-
volving cutter, turned on§the principal axis while the
nut itself is fixed in the3slide-rest, so that while the
cutter revolves in- ‘its place, the nut gradually ad-
vances upon it, instead of the cutter advancing upon
the thread, as in cutting the screw.
The Scanw, as a mechanical power, will be noticed
under S'rn'rrcs.
Scnnw or Ancnmnnns. A machine for raising
water, invented by Archimedes: it is also called the

means ‘of the power communicated to the
bevelled wheel by the engine, the wheel 20
gives rotation to the wheels a’ w". A hori-
zontal motion is thus given to the slide-rest or
sliding frame from one end of the bed to the
other, and the cutter being pushed forward by
means of the screw, a first impression of a
thread is formed in the revolving cylinder.
lVhen the frame arrives at the end of the cy-
linder, it presses on the stud n on the lever l,
and throws ‘the wheel out of ‘gear. The tool
is then brought back, the motion is reversed
by bringing the other bevel wheel in gear, and the
cutting frame, retnrns, ‘The wheel’i's now thrown
out of gear by theframe itself, as at theother end;
the tool is readjusted and made toi'cut deeper, and
thus the operation is repeated until the screw is
completed. , , _
If the screw to be cut is to ‘have the same pitch as
the permanent screw which carries the slide-rest, the
3 wheels in, iv’, in", are all equal to each other, so that
one revolution of the axle advances the cutter one
thread; but by changing these wheels, so that the
wheel 20 exceeds or falls ‘short of the other two in any; a‘
ratlo, the thread of the new screw may be made toé",v ~.
‘differ from those of the permanent screw in the same
ratio. Screws of any required pitch may, therefore,
- ~lie cut by having-a variety of wheels so arranged that
the sum of their two radii shall be a given quantity.
For cutting a screw with a double thread, one



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Fig. 1937+ --iritcrrriifi:biAnlii'scnnwi’déi .
spiral pamp, and in Germany the water-snail. Its
structure and application willjbe understood by refer-
ring to Fig. 1937, in'which'w is'a wheel linovied in
the direction of the arrow'b'y the fall of water n,
which need not be more than ‘3 feet. The axle A of
the wheel may be raised‘ so as to make an angle of
between 44° or 415° and 60° with the horizon, and on
the top of the axle is a wheel w’ which turns a similar
wheel w", having the same number of teeth, the axle
A’ of this wheel being parallel to the axle A of» the two


‘ Fig. 193s.
formerjwheels. The axle A is cut into a double
threaded screw, Fig. ‘1938, which must 'be right-
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SCREW.
591
handed if the first wheel is turned in the direction of
the arrow, and left-handed if the stream turn the
wheel the contrary way: also, the screw on the axle
A must be cut the contrary way to that on the axle
A’, because the 2 axles turn in contrary directions.
The screws must be covered over with boards, and
they will then form spiral tubes: or a tube of stiff
leather may be wrapped round shallow grooves in the
axle, as in Fig. 1939. The lower end of the axle A
revolves constantly in the stream which gives motion to
the wheel, and the lower ends of the spiral tubes open


Fig. 1939.
into the water, so that as the wheel and axle revolve
the water rises in the spiral tubes, and makes its
escape at the top through the holes 0 0, which are set
in a broad close ring on the top of the axle, into which
ring the water is delivered from the upper open ends
of the screw tubes, and falls into the open cistern 0.
The lower end of the axle A’ turns on a gudgeon in
the water in o; and the spiral tubes in that axle take
up the water from o and deliver it into a similar cis-
tern just below the top of A’, on which there may be
such another wheel as w" to turn a third axle by such
a wheel upon it. In this way water may be raised to
any given height provided there be a stream of suiti-
cient power to act on the float-boards of the first
wheel.
The water-screw, Fig. 19%), resembles the above,
only the spiral projections are detached from the
external cylinder within which the screw revolves.




Fig. 1940.

This want of perfect contact between the screw and
the cover occasions a loss; and, in general, at least
I-third of the water runs back, and the axis cannot
be placed at a greater elevation than 30° : it is also
easily clogged by impurities in the water. When,
however, the lower end is immersed to some depth in
the water, it has been found to raise more water than
the screw of Archimedes, so that if the height of the
surface were liable to any great variations the water-
screw might be preferred to the Archimedian screw.
The mode of operation of the screw of Archimedes
is thus illustrated by Dr. Gregory, in his Treatise on

Mechanics :~—“ If we conceive that a flexible tube is
rolled regularly about a cylinder from one end to an-
other, this tube or canal will be a screw or spiral, of
which we suppose the intervals of the spires or threads
to be equal. The cylinder being placed with its axis
in a vertical position, if we put in at the upper end of
the spiral tube a small ball of heavy matter, which
may move freely, it is certain that it will follow all the
turnings of the screw from the top to the bottom of
the cylinder, descending always as it would have done
had it fallen in a right line along the axis of the cy—
linder, only it would occupy more time in running
through the spiral. If the cylinder were placed with
its axis horizontally, and we again put the ball into
one opening of the canal, it will descend, following
the direction of the first demi-spire, but when it arrives
at the lowest point in this portion of the tube it will
stop. It must be remarked that, though its heavi-
ness has no other tendency than to make it descend
in the demi-spire, the oblique position of the tube,
with respect to the horizon, is the cause that the ball,
by always descending, is always advancing from the
extremity of the cylinder whence it commenced its
motion to the other extremity. It is impossible that
the ball can ever advance more towards the further,
or, as we shall call it, the second extremity of the
cylinder, if the cylinder placed horizontally remains
always immoveable: but if, when the ball is arrived
at the bottom of the first demi-spire, we cause the
cylinder to turn on its axis without changing the
position of that axis, and in such manner, that the
lowest point of the demi-spire on which the ball
presses becomes elevated, then the ball falls necessa—
rily from this point upon that which succeeds, and
which becomes lowest; and since this second point
is more advanced towards the second extremity of
the cylinder than the former was, therefore by this
new descent the ball will be advanced towards that
extremity, and so on throughout, in such a manner
that it will at length arrive at the second extremity
by always descending, the cylinder having its rotatory
motion continued. Moreover, the ball, by constantly
following its tendency to descend, has advanced
through a right line equal to the axis of the cylinder,
and this distance is horizontal because the sides of the
cylinder were placed horizontally. But if the cylinder
had been placed oblique to the horizon, and we sup-
pose it to be turned on its axis always in the same
direction, it is easy to see that if the first quarter of
a spire actually descends, the ball will move from the
lower end of the spiral tube, and be carried solely by
gravity to the lowest point of the first demi-spire,
where, as in the preceding case, it will be abandoned
by this point as it_ is elevated by the rotation, and
thrown by its heaviness upon that which has taken
its place; whence, as this succeeding point is further
advanced towards the second extremity of the cylin-
der than that which the ball occupied just before, and
consequently more elevated, therefore the ball, while
following its tendency to descend by its heaviness,
will be always more and more elevated by virtue of
the rotation of the cylinder. Thus it will after a
592
SOREW-JAGK—-SCULPTURE.
certain number of turns be advanced from one extre-
mity of the tube to the other, or through the whole
length of the cylinder; but it will only be raised
through the vertical height determined by the obliquity
of the position of the cylinder.
“ Instead of the ball, let us now consider water, as
entering by the lower extremity of-the spiral canal,
when immersed in a reservoir: this water descends at
first in‘ the canal solely'by its gravity; but the cylin-
der being turned, :the water moves on in the canal to
occupy the lowest place; and thus, by the continual
rotation, is made to advance further and further in‘
the spiral, till ~at length it is raised to the upper ex-
tremity of; the canal, where it is expelled. There is,
however, an essential diiference between the water
and the ball; for the water, by reason of its fluidity,
after having descended by its heaviness to the lowest
point of the demi-spire, rises up on the contrary side
to the original level; on which account more than half
one of the spires may soon be filled with the fluid.”
SCREVV-JACK, an instrument in common use for
raising timber or heavy weights through short lifts.
It consists of a powerful combination of teeth and
pinions enclosed in a strong wooden stock or frame,
B c, Fig. 1941, and moved by a winch or handle H 1?.
In Fig. 1942 the rack-work is shown, the stock being
removed. In the figure a very short rack is shown:
a]





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illlliinllyilanl


Fig. 1941. Fr, 1942.
it should be at least 4. times as long in proportion to
the wheel 0, and the teeth be 41 times more numerous, or
have about 3 in the inch. If the handle 11 r be 7 inches
long, the circumference of this radius will be dd inches,
which is the distance or space through which the
power moves in one revolution of the handle; but as
the pinion of the handle has but 4. leaves, andrthe
wheel 0, say 20 teeth or 5 times the numhéeggjitliere
I ht‘éw'iiév °
fore to make one revolution of the wheel~"€)‘1”~11equ1res
5 turns of the handle, in which case it passes i
5 times 44: or 220 inches: but the wheel having pinion It of 3 leaves, these will raise the rack 3 teeth
or 1 inch in the same space; hence the handle or
power moving 220 times as fast as the weight, will
raise or balance a weight 220 times greater; and if a

man’s hand sustains 50 lbs. weight, he will be able,
by means of this jack, to sustain a weight or force of
11,0001bs., or about 5 tons weight. The machine is
in some cases open from the bottom nearly up to the
wheel 0 to allow the lower claw, which in such case
is turned up as at B, to draw up a weight. When
the weight is drawn or pushed to the required height
it is prevented from going back by hanging the end
of the hook s, fixed to a staple, over the curved part
of the handle at ii. The jack is also sometimes fur—
nished with a pall and ratchet, to stop the motion of
the machine as soon as it begins to run back.
SCREW PILE -See LIGHTHOUSE.
SCREW PRESS—See Gnnn, Fig. 477—PnINTINc.
SCREW PltOPELLER—See STEAM.
SCULPTURE, MECHANICAL rnoonssns or. Sculp-
ture is the art of carving or cutting any material into
a proposed form or shape, for the purpose—1, of
representing entire figures, as in statues and groups,
called by artists the romzal; 2, of making figures either
in laig/z or low may” (all/‘o or lasso rilievo), the object
being more or less raised, but not entirely detached
from the back ground; 3, of cutting or sinking into
a ground, so as to make the object represented below
the plane of the original ground. Sculpture is also
defined as the art of representing objects by form,
(in contradistinction to painting, in which colour is
introduced,) and has thus been applied to earning, to
modelling or the plastic art, to casting in metal, and
to gem-engravingin hard and soft stones. [See SEAL-
Enenavine] _ _ _
The materials used by the sculptor are very nume-
rous,‘ but probably more so in ancient times than at
present. “For modelling, clay, wax, and stones or
plaster, appear to have been universally used: the
clay, after having been worked into the proposed form,
was frequently baked, acquiring by that process a
hardness not inferior to stone: in this state, too, it
often served for moulds, into WlllGll soft clay was
squeezed, and thus the object became easily multi-
plied. A considerable number of ancient specimens
of statues, bassi rilieoi, lamps, tiles, and architectural
ornaments in this material (called term coiia) have
been preserved. Marbles, stones, and woods of all
kinds, as well as ivory, were employed by the carvers,
and all the known metals, wax, plaster, and even
pitch, were used for the difierent processes of casting.
There was a statue of amber of Augustus; and at the
celebration of Fiirzeralia, as in those of Sylla, at public
exhibitions, or on other extraordinary occasions, we
read of statues having been made of aromatics, and
of materials of the most combustible nature; and
amongst the odd conceits of the ancient artists, may
be mentioned a statue of Venus, which attracted
aiMa'r's of iron. The combination of different materials
for the purpose of producing variety of colours, either
for drapery or ornaments, was termed polyc/zromic
sculpture (wohz‘is, many, Xpéna, colour), and those
works which were composed of a variety of' stone or
marble were, in like manner, called pokllilfiic (mats,
many, and M609, a stud). This mixture of materials,
which modern taste disapproves, was continually
SCULPTUHE—SEAL-ENGRAVING.
_593
resorted to by the most celebrated artists during the
best period of art in Greece, particularly, in colossal
works.”1
As it would be quite impossible Within our limits
to describe the modes of working up all the materials
enumerated in the above passage, we propose to notice
briefly the mechanical processes adopted in the pro-
duction of a work in marble. Many of the pro-
cesses above alluded to are described under separate
heads.
The sculptor first expresses his idea in a sketch on
paper, and then makes a small model, generally in
clay, or, for greater accuracy and perfection, a model
of the size in which the marble, bronze, or wood, 850.,
is to be executed. The figure is first modelled naked,
and in its proper action and form: he then lays on
the drapery either from studies made after the living
figure, or drapery placed on a lay figure or mnnni/ez'n.
The clay model, if large, is supported by a frame-work
of iron, and the masses of clay are kept together by
small wooden crosses attached to the iron frame-work,
by wires of different lengths dispersed in different
parts of the clay. The modeller’s tools are of wood
or ivory, with ends pointed, rounded, square, or diago-
nal, with which he forms his model, marks out the
hollows and dark parts, and does whatever his un-
aided fingers cannot eifect. The clay must be occa-
sionally sprinkled with water to prevent the model
from shrinking and cracking, and when left for some
hours it should be covered with a damp cloth. The
clay model being finished, it is moulded and cast in
plaster, the plaster being supported by iron bars
cemented, to prevent the rust coming through. The
method of taking plaster casts is described under
GrrsUM. If the work is to be executed in bronze,
particular attention must be bestowed on the mould,
to enable it to bear the weight of the fluid metal.
The model is copied in marble in the following
manner :—A number of small black points are marked
upon the model in every principal projection and
hollow, so as to give the distances, heights, and
breadths, sufficient for copying with the marble from
the model. The ancients did this by considering
every 3 points on the figure as a triangle, which
they made in marble to correspond with the same 3
points in the model, by trying it with a perpendicular
line or some other fixed point, both in the marble and
the model. The modern method is this :-—After
having ascertained by rough measurement that the
block of marble is sufficient to make the statue of the
size of the model, it is fixed on a stone base or wooden
bench, called a banker, in front of which is a long strip
of marble divided into feet and inches. A similar
strip is placed in front below the model, together
with a wooden perpendicular rule the height of the
whole work: this rule can be taken from the marble
graduated scale under the model to the marble scale
under the marble block. The rule being first placed
upon the scale of the model, and the exact distance
taken from it to any prominent part, as, for instance,

(1) Article Scunrruns—Encyciopzedia Metropolitana.
VOL. II.

the end of the nose, it is then removed to the corre-
sponding position of the other scale, and the workman
cuts away the marble to the same distance from the
perpendicular at the same height; that is, until he
has arrived at that portion of the block which is to
form the tip of the nose. He then proceeds in the
same way with some other prominent part, such as
the top of the head, until at length he has produced
a rough representation of the whole figure.
Machines have also been contrived for producing
the same efiect with greater convenience and rapidity.
One of them, called a pointing instrument, consists of
a pole or standard, to which a long brass or steel needle
is attached, so as to admit of being extended and
withdrawn, loosened or fixed, and moved in every
direction by means of a ball and socket—joint. This
instrument being made to touch a particular part of
the model, it is removed to the banker, and the
marble is 'cut ‘away until the needle reaches as far
into the block as it had been fixed at upon the model.
Apencil mark is then made upon the two correspond-
ing parts of the model and block, and a point is thus
said to be taken. By a frequent repetition of the
process, the various points at fixed depths, corre—
sponding with the surface of the model, give a rough
copy of the intended work. The work is sometimes
performed by drilling. For example, the workinan
measures how far any particular part of his mddel,
such as the tip of the nose, is from the front of the
banker, and having found the proper position of the
corresponding point of the block of marble, he drills
a hole to the same depth from the front, as in the
model. Other prominent points are, in like manner,
measured, and holes are drilled to their proper depths
from the front, until at length the block of marble
presents a honeycombed appearance from the nume-
rous drillings. The portions of marble between the
holes are cut away with the chisel, care being taken
not to chip away any of the stone below the drill-
hole. Mr. Behnes has contrived an improvedeima-
chine on this principle.
When at length the figure has thus been rang/zeal
,or blocked out, the mechanical art merges into the
fine art. The sculptor now takes the dead mass
in hand, and imparts to it that artistic life which
conveys to the beholder beauty of form, mental and
anatomical expression, and a well-defined purpose.
How this is done cannot be told in words. The
mechanical aids are steel chisels, varying in breadth
from an inch to a mere point, and for deep parts
drills are also used. The sculptor goes over
every part of the surface of the marble, urging the
chisels with hammers of from 2 to 4: lbs. each. In
this work, however, the sculptor is frequently assisted
by a superior workman, called a career, who knows by
the pencil marks how far he can penetrate into the
marble. After the chiselling the surface is gone over
with rasps, and then with sharp files. The smooth
parts are rubbed up with pumice-stone or grit-stone,
cut to suit the various forms of the surface.
SEAL-ENGRAVING is the art of sinking, in
intaglio, armorial bearings on gems and hard stones.
Q Q
‘594
SEAL-EN GRAVIN G.
When the subjects are of a more artistic kind, the
art is properly called GEM-ENGRAVING. When the
design is engraved in relief, it forms a third division
of the art,‘ viz. CAMEO-CUTTING. All three branches
have, however, in practice, a great aflinity, and the
tools and processes are ‘similar in all. The tools are
small revolving wheels, the edges of which are charged
with a fine abrasive powder, applied by means of oil
or water; the object to be engraved is held in the
fingers of the artist, and thus applied to the lower
edges of the small wheels, and is moved about into
the positions favourable to the production of those
fine lines, grooves, and hollows, which are in fact
counterparts of the small wheels or tools themselves.
For hard stones the wheels are of iron charged with
diamond powder by means of oil of bricks, the polish-
ing being performed by means of copper wheels charged
with rottenstone and water. For engraving glass,
similar but larger tools of copper are used, charged
with emery and olive oil, the polishing being effected
by means of leaden tools charged with pumice-stone
and water. ‘
All gems inferior in hardness to the diamond admit
of being operated on by the seal-engraver, and even
the diamond itself has been engraved. The sapphire
is out very slowly, but smoothly; the ruby is cut
slowly, and is apt to break off in small flakes; carnelian
and bloodstone are of close structure, and can be cut
slowly. The softer stones can be cut with greater
rapidity, but the effect is not so smooth as in the case
of the harder stones. The amethyst is as soft a stone
as can be engraved smoothly: when such soft sub-
stances as glass or marble are engraved, the tools
soon become deteriorated in consequence of the
diamond powder becoming imbedded in the material
and reacting on the tool. Stones consisting of laminae
of difierent degrees of hardness require care in the
cutting, to prevent the tool from sinking more deeply
into the softer parts. When the device is seen from
the surface in the colours of the lower stratum the
seal is called a rzz'colez'.
he seal engraver’s tools are furnished with long
conical stems for fitting into the hollow mandrel or
quill of a small lathe head or engine, Fig. 19%,
mounted onaa table, Fig. 194r3, which is hollowed out
in front, and furnished below with a light foot-wheel
for driving the engine with a steady motion. The
engine, shown separately in section, Fig. 19%, is a
brass pillar about 6 inches high, with a bolt at the
bottom for passing through the bench, where it is re—
tained by a nut. At the upper part of the pillar are
two openings which cross at right angles: these are
for the reception of the pulley and the bearings of the
quill. The bearings are usually cylindrical, and are
made of tin or pewter cast upon the quill, fitting it
by a set screw, which passes through a brass cap at
the top of the pillar. The quill is of steel, about 2
inches long and ;- inch diameter: it passes through
the ‘bearings, and has two small beads upon it for
preventing end play. The quill is hollow throughout
its length, and slightly conical, and on one side of the '
perforation is a small groove, into which passes a
feather on the tools, which prevents them from slip‘
ping round. The pulley is about 1% inch diameter,
and is generally made in one piece with the quill.


.
mmumummxmn-l







Fig. 1943. SEAL ENGRAVER’S LATHE.
The top of the pillar is covered with a small cap for
keeping away dust and grit from the bearings, and is
used as a rest for steadying the hand of the engraver.
The tools are of soft iron wire "
carefully annealed. Around the
stem of each tool is cast a
conical plug of tin, pewter, or /%l\/l7 /
other soft metal, for fitting it
into the quill of the engine. // / ’//

As it is of great importance
that the tools should run true, 1
they are fixed in the quill and
turned to the proper forms:
the rest for turning the tools is
passed through a mortice in the
brass standard. The forms of
the tools are very various, but
the general form is that of a
small disk more or less rounded
on the edges, which is the part
used in cutting. For cutting
fine lines the edge is nearly as
thin as that of a knife: a
thicker and more rounded edge
is used for thicker lines. For
sinking large shields the tools



Fig.1944.
are considerably rounded, and in some cases almost
spherical.
for removing the chief bulk of the material, while the
flatter edge is used for smoothing the surface. To
allow the tool to be applied to sunken flat surfaces
without the stem interfering with its action, the edge
is made conical, as at 6, Fig. 19415. The tools 6 a d e
are seldom larger than gth inch diameter, and they
are made so small as not to exceed TEWtl-i inch
diameter, when the tool can scarcely be distinguished

by the unassisted eye from its stein. These very



The rounded tool cuts more rapidly than
one with a nearly flat edge, and is commonly used
SEAL-EN GRAVING.
59
0
r
small tools cannot be formed by the file alone; but
when made as small as possible by that means they
are used on works of larger size until worn down
small enough to be used for making small dots and
markings in the figures of men or animals, the full
lengths of which are not more than 5}; inch. The
a. f
%_ *W‘éristdmég
b 5
' 0 h
at l}
HEW We
. e .13
Fig. 1945.
surfaces of the tools must be smooth, 2'. e. free from
creases, as the hollows are called, one of which, in a
thin tool, such as b or cl, will be likely to chip instead
of cut. The formation of creases is prevented by the
frequent use of a fine file.
The mode of preparing diamond powder is described
under LAPIDABY-WORK, Fig. 1272. It is brought
into a pasty condition by mixing with olive~oil, and
the paste is kept in a small conical cup, which every
now and then is applied to the tool, or the engraver
may wear on the forefinger of the right-hand a ring
made of a strip of tin, to which are soldered 2 little
hollow discs about i- inch diameter, one of which con-
tains a very small quantity of diamond paste, the
other 1 or 2 drops of the oil of ‘bricks. The diamond
paste is applied to the extreme edge of the tool while
in slow motion: the tool is then moistened with the
oil of bricks, and the cutting is proceeded with until
the brick-oil is evaporated. The tool must not be
allowed to become too dry, or the diamond paste
would become detached from the tool, which would
then be cut instead of the stone. Sperm-oil is some-
times used instead of brick-oil.
The stones to be engraved are brought to their gene-
ral form by the lapidary, and are often set by the jew-
eller before being engraved. They are then mounted in
a handle about 5 inches long and 3— inch diameter. If
the stone is not set, it is fixed with lapidary’s cement
upon a wooden handle, the cement being coated with
sealing-wax to prevent the cement from adhering to
the fingers.
notch made in a piece of cork or bamboo. If the
stone is hard and polished, the surface is roughened by
rubbing it upon a soft steel plate charged with a little
diamond powder and oil, or if the stone be soft, upon
a leaden plate charged with emery. The tools are
less liable to slip, and penetrate better on a rough
than on a smooth surface: and the outline of the de-
vice can also be better sketched out upon the rough
surface. The general outline is first carefully drawn
upon the stone with a brass point ; the entire surface
within this outline is then sunk: the details of the
design are next sketched in and sunk in succession.
For forming an outline, the small tool 6, Fig. 1945,
If the stone is set, it is inserted in a
is used; this is called a sharp or lmz'fie tool. The out-
line being dotted out with this tool, a thicker tool,
with a rounded edge, such as 65, may be employed for
perfecting the outline: a thicker and larger tool, such
as j; is next used for removing the bulk of the mate-
rial within the outline. The surface, when sufiiciently
lowered, is smoothed or stippled with a smaller and
flatter tool, such as e. In roughing out the work the
engine is driven rapidly, and the stone applied with
moderate pressure. A slower speed and a less pres-
sure are used when the smaller tools are applied;
and, with the smallest tools, such as are used for
cutting the details, the pressure is slight, and the
engine is driven still more slowly. Curved lines
and rounded forms are, from the circular forms of the
tools, more easily engraved than straight lines. Fine
lines, with sharp curves, such as the hair-strokes in
writing, are difficult to engrave; but the bolder lines,
in German-text initials, are far more easy of execution.
“ The cutting of the fine parallel lines on the field,
called colour Zines, presents considerable difficulty, as
they are very shallow, and to give them a uniform
appearance requires much care, and a light but steady
hand. To assist in cutting these lines equidistant,
a tool is used, having 2 knife-edges, c, Fig. 19415, and
called a colouring tool’. The front edge of this-tool is
used to cut the first line to the required depth, and
the second line is at the same time marked out by
the back edge: at the next process the second line is
cut to the full depth, while the third line is marked
in the same manner, and so on; the lines being cut
in succession from right to left, in order that the ope-
rator may be enabled to watch the progress of the
tool throughout, and the stone is held in an inclined
position to cause the greater penetration of the front
edge of the tool.”1 _
I The engraver watches his work during the cutting
through a lens of from 1 to 2 inches focus, which is
mounted in an adjustable stand directly over the tool.
The work is brushed from time to time to snow of its
being seen distinctly; but the engraver depends very
much on the sense of feeling for placing the work in
the proper position with respect to the tool, and upon
that of hearing for judging of ‘the progress of the
tool. He occasionally takes a proof of his work in
blue modelling clay,’ or in a black wax made by mix-
ing fine charcoal powder with bees’-wax.
It is of great importance that the artist should have
his hands perfectly steady, and placed so as to be
moved about in all directions with freedom. For this
purpose, it is usual for him to rest the palm of the
left-hand on the cap of the engine, Fig. 194%, while
the forefinger and thumb embrace the revolving tool,

(1) Holtzapfi‘el, “ Mechanical Manipulation,” vol. iii. The
valuable chapter on “ Gem and Glass Engraving,” describes, for
the most part, the practice of Mr. W. Warner in seal-engraving,
and of Mr. Henry Weigall in gem-engraving. In Rees’s Cyclo-
epadia is a very interesting article on Gems. A treatise on “ The
Ancient Method of Engraving on Precious Stones compared with
the Modern,” by L. Natter, Engraver on Gems, was published, in
French and in English, in 1754. It appears, from this treatise,
that the methods of engraving in use among the ancients closely
resembled those of the modern engravers.

as?
5'90
SEAL-ENGRAVING—SEALING-WAX.
and grasp the upper end of the stick on which the
stone is mounted. The thumb and forefinger of the
right-hand grasp the stick just below those of the left,
and the right elbow is supported on a small cushion.
A different form of engine would require a different
position. .
When the engraving is finished, polish is restored
to the flat ~surface of the stone by means of rotten-
stone and water applied on a pewter lap. The en-
graved surfaces of seals are not usually polished; but
those of gems are polished most carefully with copper
tools charged with very fine diamond powder. The
copper being softer than the iron, the diamond pow-
der‘ becomes more deeply imbedded in the surface of
the tools, and thus produces a smoother surface. Box-
wood tools, with still finer diamond powder, are used
after the copper tools; and then the copper tools
charged with rottenst-one and water.
Cameo'eulling, or the engraving of gems in relief, is
a similar operation to seal'engraving, or the engraving
of gems in intaglio. Tlfe stones selected for the pur—
pose are those varieties of agate called orig/weal [see
Aen'rn] which consist of two layers of different
colours, such as the black and white of the agate,
and the red and white layers of the carnelian‘. The
design is generally engraved in the white layer, the
dark ‘layer forming the background. The stone is
prepared by the lapidary, and the artist arranges his
design'according to the capabilities of the stone. He
makes a drawing in paper on an enlarged scale,
.and a model in .wax- of the exact size, and the latter
is carefully compared with the stone, and such altera-
‘ti'on's‘made as the markings on the stone seem to
require. The outline is then sketched on the surface,
.and is cut in with a knife-edged tool ('1, Fig. 19445.
The general contour of the figure is next formed, and
then the'details,'the wax'model serving as a guide.
The surface of the background is flattened by the
.broad flat surface of such a tool as cl, Fig. 19%, and
small irregularities are removed from the rounded
surfaces of the figure with the convex edge of a re-
volving tool called a spade .- it is a piece of soft iron,
3 or 4t inches long, the end of which is filed to an
(angle of d5°, and charged with diamond powder: it
is held in the fingers like a pencil, and rubbed on the
work with short strokes. The last delicate touches
are executed with very small tools, and the cameo is
smoothed‘and polished as described for the best works
in intaglio. Shell-cameos are described under SHELL.’
Engraving on glass resembles seal-engraving in all

(,1) According to Mr. H. Weigall, “ all the stones in difi‘erent
coloured layers employed for cameos, are known to practical men
‘by the general name of oizyires.” The word 0123/11: is stated under
AGATE to have been applied on account of some resemblance in
‘the stone to the markings of the human rail, or to the pink and
‘white colours observable thereon. In many cases, however, there
is, no such resemblance, at least to the eye of the mineralogist;
:but Mr. Weigall suggests “that there was an original propriety
,in the name, and that. it most probably arose from the practice of
the ancients in staining their nails; fgr if the stain were only ap-
plied at distant intervals of time, the lower portion of the nail .
would grow between the applications, and present aband of white
at the bottom of the coloured nail, and thus render it a fair type
“er the onyx stone.”

its essential features; but the designs on glass being
larger than those engraved on gems, the tools are
larger: the material also being softer, a paste of fine
flour, emery, and oil, is used instead of diamond paste.
SEALING-VVAX. Before the invention of this
substance for securing letters, a kind of bitumen was
used for the purpose, and called lerra sigillaris .- it
was, according to Beckmann, brought from Asia by
the Romans, but was first known among the Egyp-
tians. Pipe-clay was also used for seals, as was
also a cement of pitch, wax, plaster, and fat. But
there is no evidence of the use of common sealing-
wax of earlier date than the sixteenth century. The
first recorded letter sealed with it is dated London,
August 3, 1554.‘: ‘it is addressed to the BllCll’l-
grave Philip Francis von Daun, from his agent
in England, Gerhard Hermann. The wax used in
sealing this letter is of a dark red colour, very shining,
and the impress bears the initials of the writer. The
next known seal is one letter written in 1561 to the
Council of Gorlitz, at Breslau: it is sealed in 3 places
with beautiful red wax. There are two letters, dated
1563, from Count Louis of Nassau to the Landgrave
William IV. : one is sealed with red wax and the other
with black. In the records of Plessenburg is an old
“expense-book” of 1616, by which it appears that
Spaniel» wax, and other materials for writing, were
ordered from a manufacturer of sealing-wax at Nurenn.
berg for the personal use of Christian margrave of
Brandenburg. It has been supposed, from the term
applied to it, that sealing-wax was invented in Spain,
but, as Beckmann remarks, “the expression Spams/l-
ioarr is of little more import than the words Spaniel-
greerz, Spams/lilies, Spanish-grass, Spanish-reed, and
several others, as it was formerly customary to give
to all new things, particularly those which excited
wonder, the appellation of Spaniel» ; and in the like
manner, many foreign or new articles have been called
Turkish, such as TMTkiSfi—wkfllt, Turkish-paper, 820.”
According to the same authority, the first printed
notice of sealing-wax occurs in the work of Garcia ab
Orto, v“Aroma'tum et Simplicium,” 850., Antverpiae,
15741, where the author remarks that strips of lac
were used for sealing letters. The oldest printed
receipt for making sealing-wax occurs in a work by
Zimmerman, ‘citizen of Augsburg, 157 9. The follow-
ing is a translationz—“To make hard sealing-wax,
called Spanish-wax, with which, if letters be sealed,
they cannot be opened without breaking the seal :—
Take beautiful clear resin, the whitest you can pro—
cure, and melt‘ it over a slow coal fire. When it is
properly melted, take it from the fire, and for every
pound of resin add 2 ounces of Vermilion, pounded
very fine, stirring it about. Then let the whole cool,
or pour it into cold water. Thus you will have beau-
tiful red sealing-wax. If you are desirous of having
black wax, add lamp-black to it. With smalt or
azure you may have it blue; with white-lead,‘ white;
and with orpiment, yellow.”
The French also put in a claim to the invention.
.It is stated that one Francis Rousseau, having, atthe
end of the reign of Louis XIII, lost all his property
SI'IALIN G-WAX—SEBACIO ‘AGID—SELENIUM.‘
in a fire, in order to maintain his family prepared
sealing-wax from shell-lac, as he had seen it manu-
factured in India. Sealing~wax was common in For-
tugal about the year 1560, and is supposed to have
been introduced into that country from India. In
the Portuguese Court of the Great Exhibition some
sealing-wax was exhibited closely resembling that of
Indian manufacture.
The manufacture of sealing-wax was long monopo-
lized by the Dutch, as is evidenced by the legend,
“ BRAND wnLL EN vxsr noun,” (Burn well and hold
fast,) and this stamp was long adopted by English
and other makers; but as it came at length to be
placed on wax of all qualities, good and bad, it fell
into disrepute, and the name of the manufacturer was
preferred. The term Daniela—war now refers to an
inferior description of the article.
The term were: applied to this article is a misnomer.
No wax is used in its manufacture, but resin, which
is essentially different in its properties. The large
seals on public documents are, however, really made
of bees’-wax,1 and it was natural, on the introduction
of the resinous compound for sealing letters, to apply
the term wax to it; especially as the chemical dis—
tinctions between such substances as resin and wax
could not at the time have been very well understood.
The best kind of resin for making sealing-wax is Size!!-
Zae. [See LAQ]
The best red sealing-wax is made by melting A lbs.
of light-coloured or bleached shell-lac with llb. of
Venice turpentine and 3lbs. of Chinese Vermilion.
The ingredients must be stirred well together, and
when the mixture is nearly set a quantity sufficient
for 6 sticks is weighed out. The sticks are made on
a raised marble slab, heated by a chafing-dish placed
underneath. The wax is rolled on this slab with the
hands into a roll of nearly the length of 6 sticks, after
which the proper length and thickness are given by
rolling it with a square piece of hard wood. The stick is
then taken by another workman, who rolls it upon a
cold marble slab with a marble roller until it is cold.
The stick is polished by holding it between two char-
coal fires, placed opposite each other, a short distance
apart: the melting of the wax produces a smooth sur-
face. Five deep indentations are made in the wax, so
as to divide it into 6 equal parts. A third workman
.breaks the long sticks into the short lengths, and
finishes the top by holding it in the flame of alamp,
and impressing the maker’s seal upon the end.
Oval, grooved, channelled, and other ornamental
forms, are made by pouring the fluid wax into steel
moulds. Golden sealing-wax is made by using pow-
dered yellow mica, or cat-gold, instead of Vermilion.
Blue wax is made by colouring the resin with smalt
or verditer: ivory-black is used for black wax; mas-
sicot, or turbith mineral, for yellow, and so on. Wax

(1) The Great Seal of England is made up according to a recipe
in the Lord Chancellor’s Ofiice. It is said to be prepared by melt-
ing block-white wax in about l-fourth of its weight of Venice
turpentine. The wax of the Great Seal and Privy seal of Scotland
is made from resin and bees’-wax coloured with Vermilion. The
Exchequer Seal is green. Seals made of soft wax are not pal-ma-
nent, and the impression is dull.

597
may be rendered fragrant by adding to the other in-
gredients ambergris, musk, oil of rhodium or oil of
benjamin, &c. The addition of camphor improves
the burning, but renders it unfit for use in warm
climates.
An inferior wax is made by substituting common
resin for the lac, red lead for the Vermilion, and com-
mon turpentine for that of Venice. Sticks of this
wax are made to appear like wax of good quality, by
softening them between two fires, and then rolling
them in powdered wax of a better quality: the sticks
are again softened to melt this false coating and pro-
duce a polish. For inferior black wax, lamp-black is
used instead of ivory-black.
Although in sealing letters the most expeditious
plan is to ignite the wax, this does not give the best
impressions of the seal. With the finest red wax
good impressions can be made at a temperature of
140°. The beautiful proof impressions of seals made
by the seal-engravers are taken by first brushing the
seal with a soft brush, warming it by moving it round
the flame of a candle, until just hot enough to be
borne without pain by the naked hand; then apply-
ing to the seal a thin layer of clean tallow, by means
of a small brush, and coating this with a thin layer
of Vermilion, applied by means of a camel’s—hair
pencil. The sealing-wax is prepared by softening it
at a short distance from the candle until a sufficient
quantity can be detached for the purpose; but the
wax must not be ignited nor blackened. The softened
,wax is placed in a small heap upon a piece of stout
paper, and gently warmed, by holding it above the
flame, high enough not to blacken the paper. The
wax is stirred with a small stick for the purpose of
excluding air-bubbles and working it up into a coni-
cal mass. When the surface of the wax is bright and
quiescent, the seal, which should be of about the same
temperature as the wax, is quickly dabbed upon the
wax with a firm perpendicular stroke and moderate
pressure. By thus suddenly dabbing the seal down,
the wax is forced into the minute crevices of the seal
more effectually than by a long continued pressure.
SEASONING. See TIMBER.
SEA-WATER. See SODIUM—WATERS MINERAL.
SEBACIO ACID,2 a constant product of the de—
structive distillation of oleic acid, oleine, and all fatty
substances containing them. It is extracted by boil-
ing the distilled matter with water: it forms small
pearly crystals, and has a faint acid taste. It is com-
posed of G10H803.
SEGGAR. See POTTERY and PORCELAIN, Sec.VII.
SELENIUM, (Se 40), a rare substance discovered
by Berzelius, in 1817, while examining certain sub-
stances in the sulphuric acid manufactured at Grip-
sholm, in Sweden. It resembles sulphur in its
chemical relations, and in some few places occurs
associated with that mineral, or taking its place in
certain metallic combinations, as in the seleniuret of
lead of Claiisthal in the Hartz. Selenium is a brittle
solid, of a reddish-brown colour, and with an imper-

(2) Sebaceus (Latin), a tallow candle.
598
SENNA—SERPENTINE—SE WER.
feet metallic lustre. Its sp. gr. is 4:2 to 4'3. It fuses
at about 212°, and boils at 650°. When heated in
the air its odour resembles that of decaying horse-
radish. It is insoluble in water. There are 3 oxides
of selenium, 2 of which, selenious and selenic acids,
correspond with sulphurous and sulphuric acids. The
seleniates bear a close analogy to the sulphates.
SELZER WATER. See WATERS MINERAL.
SENNA. The dried leaves of certain annual legu-
minous plants of the genus Cassia, natives of Arabia
and Egypt. Their useful medicinal properties are
well known. The leaves of plants belonging to other
genera are mixed with senna as adulterants. The
great supply of senna to Europe is obtained from
Alexandria: Calcutta and Bombay also export a large
amount under the name of East India senna, but
which is originally brought from Arabia.
SEPIA, a valuable pigment, used by artists, and
named after the molluscous animal (Sepia) which pro-
duces it. The common cuttle-fisb, Sepia qliez'aalz's, is
about a foot in length, of an oval form, and jelly-like
substance, covered by a coarse skin. r;l‘he body is
supported by an internal plate or shell, hard in tex-
ture, and white in colour, but composed on one side
of very delicate layers of shelly matter, which rise
perpendicularly in laminae, of beautiful construction,
well worthy microscopic examination. This is the
ordinary cuttle used as pounce and as a polishing
powder for soft metals. The cuttle-fish has 8 arms
and 2 long feet, all situated near the head, (hence
these creatures are called Uepkalopodg) and furnished
with suckers, which enable it to hold fast the fish on
which it preys. It has also a parrot-like beak, which
makes it a formidable enemy. As a means of defence
when attacked, the cuttle-fish is provided with a
bladder-shaped sac of fluid resembling ink, which it
can discharge in a moment, and which ‘darkens the
water round it so completely as to favour its escape.
The ink obtained from this, and from two other species
of cuttle-fish, forms when dried the well-known sepia.
The whole family of this mollusk secrete an inky fluid;
but that of S. qfiiez'aalis, ;S'. z'olz'go, and S. tam'eaz‘a, is
most valued. The sac containing it is extracted, and
the ink dried rapidly, or it becomes putrid. Sepia.
consists of carbon in a minutelyldivided form, albu-
men, gelatine, and phosphate of lime. Caustic alkalis
dissolve and turn it brown, but as the alkalis become
carbonated the sepia falls down. The dried .sepia is
prepared for the use of the artist by first triturating
it with a little caustic lye, then adding more lye, and
boiling half an hour. The liquid is then filtered, the
alkali is saturated with an acid, the precipitate depo-
sited, washed with water, and finally dried at a gentle
heat.
in grain. It is a remarkable fact, that sepia has re-
mained unchanged in its properties for countless cen-
turies. Among the petrified remains of the ancient
world, sepia was found in the bodies of extinct cepha-
lopods. In the has of Lyme Regis ink-bags were
found in a fossil state, still distended as when they
formed part of the organization of living bodies. Dr.
Buckland, who states this fact in his Bridgewazfer
Sepia is of a good brown colour, and very fine .

Treatise, says—-“ So completely are the character and
qualities of this ink retained in these specimens, that
when, in 1826, I submitted a portion of it to my
friend Sir Francis Ghantrey, requesting him to try its
power as a pigment, and he had prepared a drawing
with a triturated portion of this fossil substance ; the
drawing was shown to a celebrated painter without
any information as to its origin, and he immediately
pronounced it to be tinted with sepia of excellent
quality, and begged to be informed by what colour—
man it was prepared.”
SEPTARIA, lenticular concretions of clay iron-
stone intersected by veins of calc-spar. When cal-
cined and ground to powder they form a good hydrau-
lic cement. See Monrsns and Gnnnnrs.
SERPENTINE, also called Ola/lite, includes several
varieties of hydrous silicates, of magnesia with iron,
manganese or chrome, and sometimes alumina. Pre-
cious serpentine is a beautiful marble, forming, when
mixed with limestone, nerd am‘z'qae. Slabs of serpen-
tine are sometimes used for the floors of bakers’
ovens.
SEWER,‘ a subterranean passage formed for the
drainage of a town. The ancient Romans seem to
have been far in advance of the moderns in respect of
sanatory regulations, for they took especial pains to
secure those two great necessaries of urban life, an
abundant supply of water and efficient drainage.
Covered drains, or sewers of great magnitude and of
solid construction, still exist under the streets of
‘some ancient Roman cities, and the cloaeae or sewers
of Rome are .of such vast size, that some writers have
supposed them to be the remains of a city more
ancient than that of Rome. In modern times the
sewers of London are unrivalled for extent and ex-
cellent construction ; and although they are not equal
to the wants of a vast and constantly increasing po-
pulation, yet, when we come to consider fairly the
difficulties of the case, it may excite surprise that so
much has been done, and so well, within a compara-
tively short ‘period. It is much more easy to point
out defects in the existing system than to suggest
a remedy that shall work as well in practice as it
reads well on paper. For instance, we are told, and
the fact is undoubted, that the drainage of a large
town, which is poured to waste into the river which
passes through it, poisoning the waters and rendering
the air pestilential, would, if properly distributed over
its banks, bestow upon them unbounded fertility.
But when we consider that the excrementitious mat—
ters produced by each individual may amount to an
annual quantity equal to one ton in weight, and that
the other .matters included under house sewage and
street drainage, may amount to .a similar quantity,
we have thus a total equal to two tons per annum for
every individual of the population. Taking the po-
pulation of London at two millions and a half we thus
have five million tons of drainage to dispose of every
year, and how to get rid of this without contaminating

(l) A sewer being a place whence water issues or sues, we thus
get the word suem or sewer. The word is sometimes pronounced
shore.
SEWER.- -
599
the Thames, or polluting the air of London; how to
extend its fertilizing presence over the arable lands
and the pastures of the surrounding country, we con-
fess ourselves unable to state, or even to admit that
the plans submitted for the purpose are within the
means of the metropolis.
It was certainly an act of sad necessity which led
men to convert streams of pure water into channels
of filth and refuse. Some of the old writers speak of
the natural water-courses of old London as being
“choice fountains of water, sweet, wholesome, and
clear.” Under this designation come the rills which
descended from the high ground about Hampstead,
and by the union of their tributary streams formed
the Fleet river. It appears, however, that so early as
the year 1290, the monks of White Friars complained
to the king and parliament that the putrid exhala-
tions arising from the stream were so powerful as to
overcome all the frankincense burnt at their altars,
and had even occasioned the deaths of many of the
brethren. Attempts were made to cleanse the Fleet
river and to restore it to its former condition as a
navigable stream; but the necessity of providing for
the wants of the population increasing on its banks
defeated the attempts, and in course of time the Fleet
dyke or ditch became a great arched sewer, receiving
the contents of innumerable subsidiary sewers and
drains, and discharging its filthy load into the
Thames.
The Fleet is only one out“ of many of the main-
sewers of the metropolis,1 all pouring into the Thames,
and all having an increased duty to perform as the
suburban dwellings increase in number. There is no
denying that this system of drainage is an evil, but
how vastly greater is the evil to those districts which
have no drainage, or only a very imperfect drainage,
will appear from the high testimony of Dr. Southwood
Smith, who, in his evidence before the Parliamentary
Committee on the Health of Towns (1840) said :—
“ If you were to take a map and mark out the dis—
tricts which are the constant seats of fever in London,
as ascertained by the records of the Fever Hospital,
and at the same time compare it with a map of the
sewers of the metropolis, you would be able to mark
out invariably, and with absolute certainty, where the
sewers are, and where they are not, by observing
where fever exists ; so that we can always tell where
the Commissioners of Sewers have not been at work
by the track of a fever.”

(1) Some of the principal sewers of the metropolis are, on the
North :—1, the Counters’ Creek; 2, the Ranelagh Sewer; 3, the
King’s Scholars’ Pond Sewer; 4, Scotland Yard; 5, the River
Fleet; 6, Finsbnry and Shoreditch Sewer; 7, Limehouse Creek, or
the Black Ditch; 8, the River Lea. These sewers drain col-
lectively 18,640 acres of land. The high lands comprise 13,700
acres, but the remaining 4,940 acres are only a few feet above,
and in some cases are below the Thames high-water~marks.
The drainage tributaries South of the Thames are :—l, the River
Wandle; 2, the Rivulet between Wandsworth and Clapham Com-
mon; 3, the Efi‘ra Brook at Vanxhall Bridge; 4, the Battle
Bridge Sewer below London Bridge; 5, the Duflield Sewer;
6, the Earl’s Brook; 7, the Ravenshourne. These drain 15,000
acres of land. The high lands, comprising 6,790 acres, sometimes
flood the low marshy district of 6, 700 acres lying between them
and the Thames.

It has been somewhat unfortunate that the difi'erent
districts into which the metropolis is divided, as
respects its sewers, should have been managed by
distinct sets of commissioners. The consequence has
been that the sewers of one district have been enlarged
without any reference to the capacity of sewers at a
lower level. Thus the sewers of the Holborn and
Finsbnry divisions have no outfalls of their own into
the Thames, but communicate therewith through
those of the City of London Commission. When the
sewers of the two first-named commissions were im-
proved and enlarged, they occasionally poured so
large a quantity of water into the City of London
sewers, that the latter were unable to discharge it, so
that during heavy falls of rain the water was forced
up the drains into the neighbouring houses. The
city was thus compelled, at great expense, to enlarge
its sewers, whereas, if the respective commissioners
had concerted their measures together, the enlarge-
ments and improvements would have been carried on
simultaneously, and the inconvenience avoided. Some
idea may be formed of the quantity of drainage which
has to be discharged by these vast subterranean works
by the following brief statement of some of their
dimensions :——The Irongate sewer, which was formerly
the City ditch, varies in height from 6 feet 6 inches
to 11 feet, and in width from 3 feet to a feet. The
Moorfields sewer is 8 feet 6 inches by '7 feet, and at
the mouth 10 feet by 8 feet: at the north end of the
Pavement this sewer is 27 feet below the surface. The
Fleet ditch, which drains from the south-west of
Highgate to the Thames, is partly formed in two
distinct sewers which run on each side of Farringdon-
street; they are from 12 feet to 141 feet high, and each
is 6 feet 6 inches wide; but they are liable to be
flooded by the rush of waters from the north, and a
single storm will, in a few minutes, raise the water 5
feet in height in both sewers. The Fleet sewer con—
veys the drainage of about 4AM: square acres of
surface in the Holborn and Finsbnry and the City of
London divisions, and it is calculated that this sur-
face discharges annually into the sewer about 100,000
cubic yards of matter, held in mechanical suspension,
and carried to the Thames by the force of the water
which flows through the sewer. The water is about
100 times the bulk of the matters suspended in them:
hence the Fleet sewer discharges from the above
limited surface about 10,000,000 cubic yards of
sewage into the Thames annually. The total work
of the sewer is however much greater than this. A
sewer carried up to Holloway in this division for a
length of nearly 3 miles,2 passes under Canonbury at
Islington at a depth of 68 feet from the surface ; the

(2) Referring to this sewer, the Surveyor of the City Division
remarks :—“ The sewer from Moorfields to Holloway appears to
measure upon the map about three lineal miles. In process of
time, and as buildings increase, it may throw out branches in all
directions, and the three miles may become thirty ; not only all
the atmospheric waters which may, upon an average, fall within
the valley south-eastward of Highgate, or at least a large portion
of them, but all the artificial supplies which the wants of its yet
future inhabitants, as well as of those intermediate, between
Islington and Moorfields, may require, will have to be carried off
by the City Sewers.”
600
SEWER.
drainage of the houses in that part being provided for
by a subsidiary sewer.
Another defect arising from want of unity of plan
in the construction of the metropolitan sewers, is
the want of a uniform rate of declivity sufficient
to discharge the sewage. Indeed many of the
sewers are laid perfectlyr level, and hence act as cess-
pits instead of channels of discharge. To remedy
the evils of insufficient declivity the process of flash-
z'wg has been adopted in the sewers; that is, the
water is allowed to accumulate for a time by means
of gates or dams, and is then suddenly let loose so as
to act like a powerful current in sweeping all the
loose matter before it. Another consequence of the
low level of many of the London sewers is that their
outfalls into the river are so low, that their contents
are delivered at or a little above, low-water level.
The consequence is that the decomposing matters are
left upon the banks of the river to stagnate and to cor-
rupt the air; and the next tide extends the pollution
by carrying them higher up the stream, and thoroughly
mixing them with the waters. If an adequate fall
could be procured the sewers might be made to dis-
charge into the river at or near the high~water level,
in which case the sewage would be conveyed away
from the higher to the lower districts. In some cases
the water of the rising tide enters the sewers and pre-
vents for the time the discharge of sewage, so that
the gaseous products of the decomposing matters in
the sewer are driven back towards the town. In other
cases the tide is prevented from entering the sewers
by closing their lower ends with valves or heavy flaps,
and men, named flap-keepers, are appointed, whose
duty it is to open the flaps at proper times, so as to
allow the sewage to escape at low water. In the
Pimlico district, adjoining the palace, the fall for the
last 5,500 feet is only 5 feet, and the outlet is furnished
with flood gates, which are kept closed for 6 hours,
during the rising of the tide. Sewers also not only
require to be flushed but also to be cleansed by hand,
the foul matter being raised to the surface in buckets
and carted away. In the Westminister division the
outfalls to the river vary from 10 to 15 feet below
the level of high-water mark, that is, about 5 feet
above low~water mark. The cost of cleansing
these sewers by hand, thus required by the deficiency
of fall, amounted on an average of '7 years to about
1,55OZ. a-year, and the deposit is sometimes found to
be so hard that it requires the use of the pickaxe to
dislodge it. Some of the main sewers in this division
have a fall of only % inch in 100 feet.
The forms of sewers vary in different districts. In
the Westminster district they are built of the form
represented in the transverse section, Fig. 1946, of
which the height varies from 5 feet to 5 feet 6 inches,
and the width from 2 feet 6 inches to 3 feet. The
regulations for building sewers issued by the Com-
missioners require that the bricks used be “good,
square, hard, sound, and well-burnt stock bricks, and
be properly laid in well compounded mortar, made of
one part of good strong stone lime, and 2 parts of
clean river sand 5 the workmanship to be of the best
’ description, the bricks of each arch to be well bonded,
and the bricks of the arch at the bottom of the sewer
to be laid close at
the top edge, and
to an even curva—
ture on the upper


surface, bedded __________________ -- *{IH'HI‘FEL
\ 'l l l‘ 1
1n mortar and m“ " m nnlliilfiim
‘I ll
grouted.” When aiifiil'liiin
' ill ll lllllll
Roman cement 1s gigging‘
' . . ll -
used in the works ,i‘u'qn'u
“ 1t shall be of the "it
best quality, and _f{ i'‘' Win"
ill Hill
1/

shall not be mixed
with more than
one half of clean
river sand.” The
form of sewer represented in Fig. 1946 is not cal-
culated to give the greatest strength: indeed, in
some cases, the sides have given way to the pressure
of the earth behind them. In the IIolborn and
Finsbury commission the oval form, Figs. 194.7, 1948,
is preferred. The part where the joints are marked
in the engravings is directed to be worked in blocks
____ __.-- -.-.----_-_ _...


X/"L/
\ i
l
N‘;
‘,3. 4n Bin.
'1
/’
///

miss, I? 31a.
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w, "/‘l f‘““\\\
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Fig. 1948.
with cement. It is required by this commission that
every main or leading sewer, “ which may receive the
sewage from streets and places containing more than
200 houses, shall be of an oval form, 5 feet in height
and 3 feet in width in the clear: the invert thereof to
be worked one brick in substance, and the springing
walls thereof to be worked one brick and a half in sub-
stance, and bonded, and the crown thereof one brick
in substance, in two separate half bricks,” as in the
transverse section, Fig. 1%7. All branch sewers which
may receive the sewage from streets containing less
than 200 houses, are to be 4. feet 6 inches in height,
and 2 feet 6 inches in width in the clear, the whole
being worked one brick in substance, the bottom and
springing walls being bonded, and the crown worked
in 2 separate half bricks, as in the section, Fig. 1M8,
which is called the second size. The sides of these
sewers form curves of large radius, struck from
centres on the line a a : the radius for the larger size
being about 13 feet, and that for the smaller size in
proportion. The difference in expense between sewers
of the sections, Figs. 19%, 1M8, has been estimated
at 1,660]. per mile in favour of the egg-shaped or
oviform section. The inverted arch which forms the



SEWER?
601’
bottom of a sewer adds greatly to. its strength, and
assists the motion and force of the current. In the
Surrey division the soil is in some places -so bad
from the pressure of quicksands that cast-iron bottoms
have been used.
The inclination and depth of sewers must be re-
gulated according to circumstances. The Holborn
and Finsbury regulations require that "‘ the inclination
be not less than 1}; inch to every 10 feet in length, and
as much more as circumstances will admit in those
portions that are~in a straight line, and double that
fall in portions that are curved.” It is stated in the
regulations of the Westminster Commission (1836)
that the currents required for sewers in all cases is
l-i— inch to every length of 10 feet; but later regula-
tions order “that ‘the current of all sewers to be
built, be regulated by the commissioners according to
surface required to be drained,” without stating any
particular inclination. It is, as already observed,
frequently a matter of difficulty to obtain sulficient
inclination in a sewer, and yet to make it deep enough
to drain the basement story of the neighbouring
houses, some parts of the metropolis being below the
level of high water. In crowded districts also, where‘
deep and capacious sewers are most required, it has
been found necessary during their construction to
shore up the houses with massive timber framings, to
prevent them from falling, and in some cases the
danger to the houses has prevented the formation of
any sewer at all. Such houses are, therefore, fur-
nished with cesspools, which are permanent sources
of offensive and unwholesome effluvia, and unless con-
'structed with good substantial brickwork, the liquid
contents will saturate the soil, and finally appear at
the surface, or escape through some defective founda-‘
tion, and poison the basement of an adj oiniug building.
As the cesspools become filled they must be emptied.
This was formerly done by taking out the contents in
buckets, and filling them into a night-cart, a slow,
disgusting, and expensive operation. It is now done
quickly and cheaply by means of a pumping apparatus,
consisting of a close tank mounted'upon 2 or 4! wheels,
with a hose fitted to an aperture in it, and an air-
pump attached: the hose is of such a length that it
may be laid through the passage, &c., of a house, and
dipped into the cesspool, while the other end is
attached to the tank at the street door, into which
the contents of the cesspool are rapidly transferred by
a labourer at the pump. The contents of one large
cesspool, equal to 241 loads of soil, can be pumped out
in about 41 hours, at a cost of 248. Under the old
system 3 nights would have been occupied in empty-
ing such a cesspool, and the cost would have been at
least 2111!.
Sewers receive the drainage of houses by means of
small channels or dining, ‘usually of circular form, and
from 6 to 9 or 15 inches in diameter, for which purpose
the lowest part of the building should be at least 41 feet
above the level of the sewer, measuring to the bottom
of the side wall or commencement of the invert. If
this precaution be not taken the house will be liable
to be flooded from the sewer when the latter is un-

usually full.1 The Westminster commissioners re‘
quire that the bottoms of private drains shall be 12
inches above the bottom of the sewer; and they re-
commend that such drains have a fall of at least ~i~inch
in a foot. If the length of the drain be 60 feet, the
fall amounts to 15 inches, which, added to 13 inches
for the height of the drain and brick arch over it,
8 inches for the depth of ground and paving over the
upper end of the drain, and 12 inches between its _
lower end and the bottom of the sewer, gives the
total fall of 41 feet. The brick rings at the junctions
of private drains with the sewers, are usually made by
the commissioners at the cost of the proprietor of the
drain. The various metropolitan commissions are
however by no means uniform in their regulations.
for the construction either of sewers or of drains.
Glazed stoneware pipes are excellent substitutes for
brickwork in the smaller drains. They are more
quickly laid than the others can be built, and theypre-
sent a much better surface for the rapid flow of the
sewage. They are constructed in various forms of
bends and junction pieces, and from the comparative
thinness of these pipes a much larger capacity is ob-
tained with a given quantity of excavation for laying
them, than brickwork sewers, which even for the:
smallest diameter cannot be less than half a brick, or
4:}, inches in thickness. Each pipe has a socket at one
end for receiving the plain end of the adjoining pipe.
In order to obtain entrance to the sewers it was
formerly the practice to construct man-holes at every
intersection of the sewers. These holes were oblong
shafts of brickwork, carried up to within 18 inches of
the surface of the road, and covered with cast-iron
plates, over which the roadway was formed. Hence, in
order to obtain access to the sewer, it was necessary
to break up the road. This inconvenience led ‘to the
formation of side entrances or passages, extending
from the side of the sewer bya short passage or tun—
nel to a square or rectangular shaft, opening into the
foot pavement, where it is closed by a trapdoor con-
sisting of pieces of flag—stone mounted in an iron
frame. On raising this cover it is held open by a
self—acting catch, and an iron grating rises in its
place, and while admitting light and air to the pas-
sage prevents the passenger from falling in. The
shaft is provided with hand-irons built into. the wall,
by which a man can readily descend and ascend.
The surface drainage of the streets is conducted
into the sewers by means of gully-holes and shoots,
Fig. 19419. In this figure is shown a very simple
plan for preventing the eflluvia of the sewers from
escaping into the streets. g is the grating, imbedded
as usual in the pavement of the gutter. (Z is a pas-
sage leading to the sewer, and the vertical shaft is
carried down below this passage, the bottom of the
shaft being formed into a receptacle for the solid
matter or mud which enters with the water : this can
be cleaned out about once a month or oftener as

(1) Such an accident sometimes happens during the artificial
scouring or flushing of the sewers: the sewage is forced up into
the streets and houses from some of the lower sewers which be~
come overcharged with the flushing water.
602-
SEWER.
required. ' The curtain wall or dipping valve, at 0,
extends a little below the level of the entrance to the
sewer, so that when the well is filled to the level of
III l
1m _ . g - ' ~




t-'__.-‘~ -__-
.72»...








ll?
_ _ "W
m
—'_'—_~~
.- “-
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‘:1.
p a“.
i
l


Fig‘. 194.9.
the inclined passage it allows water to flow freely into
the sewer, but prevents air from escaping from the
sewer into the gully—hole.
The necessity for some contrivance of this sort, if
the foul air ‘of the sewers cannot be otherwise got rid
of, will be evident from the statement made by Mr.
Fuller, a medical man, to the parliamentary committee
of 1834:, viz. that of all the cases of severe typhus
that he had seen, 8-tenths were in houses either un-
trapped from the sewers, or which being trapped were
situated opposite to gully-holes; and cases were men-
tioned in which servants sleeping in the lower parts
of such houses were invariably attacked with typhus.
It is also stated that butchers’ shops cannot exist
opposite or near to untrapped gully-holes, in conse-
quence of the injurious action of the eflluvia on the
meat.
The trapping of the gully-holes has the effect of
confining in the sewers the gases arising from the
fermentation of the putrid matters of the sewage; and
as some of the compounds of hydrogen are thus
evolvedin large quantities, these gases form, with the
common atmospheric air of the sewers, an explosive
mixture, thus exposing the lives of the men whose
duty it is to enter the sewers with lamps. Hence it
is necessary to provide some means for the escape of
the gases from the sewers, and for this purpose the
commissioners of some of the districts require the
gully-holes to be kept open, not allowing them to be
trapped; but even these numerous vents are not
sufficient for the escape of the putrid gases. It has
therefore been proposed by Mr. Fuller to burn out
the foul air from the sewers; for which purpose he
proposes to erect, as near as convenient to the
highest point of every main sewer, a large furnace
with a tall chimney, so ‘connected with the sewer that
the fire shall be supplied with air from the sewer
only. The lower end of the sewer is to be closed
with a trap that will allow water, but not air, to
pass; so that air may only enter at the gully-holes,

of which a sufficient number must be left open to
supply the furnace with air, the remainder being
trapped. By thus maintaining a constant downward
draught in the gully-holes, and passing the air of the
sewer through the fire, it was supposed that the
poisonous gases would be burnt, and by discharging
the products of combustion at a great elevation, the
nuisance of the gully-holes might be got rid of.
It has also been proposed that the large fires of
some manufacturing establishments might be usefully
applied to the ventilation of sewers.
The entrances to private drains are usually secured
by aszfz'n/r-tmp, a simple and convenient form of which
is represented under ABATTOIR, Fig. '7. These traps
are constructed in a variety of forms, but they de-
pend for their action upon the formation of what the
chemist calls a water-lute, the principle of which is
shown in Fig. '7, and also in Fig. 1949.
Our space will not allow us to enter into the details
of the numerous schemes which have been proposed
for providing for the sewage of the metropolis without
discharging it into the Thames. Mr. John Martin,
the artist, proposed, so long since as the year 1828,
that the sewage should be discharged into spacious re-
servoirs, to be formed near the banks of the Thames, in
which reservoirs the solid matter might subside so as
to become useful as manure; the watery part was
then to be discharged into the river. Another plan
is to conduct the sewage several miles below London
before it is allowed to enter the river. A few years
ago the “Metropolitan Sewage Manure Company”
was formed for the purpose of “ conveying the sewage
water of London by means of a system of pumping
engines and pipes, analogous to that of the great
water companies, and thus distributing the fertilizing
fluid over the land in such manner and proportions
as may be best adapted to the various kinds of field
and garden cultivation.” Mr. Wicksteed has pro-
posed to carry away the entire sewage of the metro—
polis in atu1mel of from 8 to 12 feet in diameter, and
at a depth of from A0 to 80 feet beneath the surface of
the streets. The sewage was to be discharged into
a large reservoir, and works to be constructed in an
angle between the western banks of Barking Creek
and the northern banks of the Thames. “The sewer
water was to be raised by steam-engines from the
receiving reservoir into other reservoirs, sutficiently
elevated to permit the solid matters to be deposited
at a level above the Trinity high~water mark. From
these reservoirs the solid matter was to be periodically
removed, dried by artificial means, and then com-
pressed and packed for transmission by land or water.
The liquid matter was to be discharged as worthless
at all states of the tide.” Another plan, by Mr. Higgs,
patented in April 1846, embraced the chemical treat-
ment of the sewage. It was to be received into
reservoirs with suitable buildings over them, in which
the gases evolved are to be collected, condensed, and
combined with chemical agents, and the salts thus
formed were to be crystallized on an arrangement of
spars or bars. The solid matters were to be dried and
cut into suitable shapes for transport as manure. ' For
‘"s‘HAenn'EN-SHEITL.
603
further details on this subject we refer to the Report
of the Committee appointed in 184.6 to consider plans
for the application of the sewage of the metropolis to
agricultural purposes.1 .
SHAFTS or AXLES. See COUPLINGS—GEARINGS
——-WHEEL.
SHAGREEN, a dried animal skin, differing from
leather in not being tanned or tawed. It bears some
resemblance to parchment, but the grain or hair side
is granulated or covered with small round rough
specks. It is an oriental manufacture, and the method
of preparing it was long kept secret. It is said to
be prepared from the skins of horses, wild asses and
camels, those portions being preferred which cover the
chine. The fillets of skin are steeped in water until
the hair is sufficiently loosened to be scraped off; the
skins are then stretched upon a board, and are un-
haired and fleshed with a knife. Each fillet is then
stretched in a frame, as in the preparation of parch-
ment, [See PARCHMENT, Fig. 15 80,] and is moistened
from time to time and gradually distended. While
still moist, the grain or hair side is sprinkled over
with the seeds of a kind of Obenrgioclinm ; they are
hard, of a shining black colour, and about the size of
poppy seed. These seeds are forced into the surface
of the skin by the pressure of the feet, or by means
of a simple press, a piece of felt or thick stuff being
laid over the seeds. In this state the skin is left to
dry in the shade, and when the seeds are shaken out
by beating the skin, the surface of the latter is pitted
with small hollows corresponding with the forms of
the seeds. The skin is now stretched on an inclined
plane, by attaching its upper end to hooks and fasten-
ing weights to its lower end, and it is thinned off with
a half-moon knife, Fig 1590, care being taken not to
cut so far as the bottom of the little pits occasioned
by the seeds. On macerating the skins in water they
swell, and the pits become prominent over the shaven
surface. The process is completed by steeping the
strips in a warm solution of soda; salt brine is then
used, and the skins are ready for the dyer.
SHALE, a term applied to any argillaceous deposit
naturally divisible into laminae parallel to the plane
of deposition. Thus there are suing, calcareous, purely
argillnceons, and carbonaceous shales; there is also a
blacl: and a brown bituminous shale; the latter, met
with at Kimmeridge in Hampshire, is called Kimme-
rirlge coal.
SHAMOY. See LEATHER.
SHAPING MACHING. A machine under this
name was introduced by Brunel for shaping the wood
in the manufacture of ship’s blocks. [See BLOCK, Fig.
153.] The morlising engine of the block machinery,
Fig. 151, was applied by Mr. Roberts of Manchester
to the formation of the key-ways of cast-iron wheels,
and also to the paring or planing by short strokes of
the sides of small curvilinear pieces of metal, such as

(1) Mr. Dempsey, in his Treatise on the Drainage of Towns and
Buildings, published in 1849, in Weale’s Rudimentary Series, gives
the details of an original plan for the drairmge of London. Much
valuable information respecting Sewers is given in the “ Report
of the Commissioners of Inquiry into the State of large Towns
and populous Districts. 1843 ”

cams, short levers, and other pieces which do not
admit of being finished in the lathe. The machines
thus introduced were first called beg-groove engines,
and afterwards the slolling and paring mosebine. Still
later another machine for shaping metal pieces and
parts of machinery was introduced under the name of
the sleeping mac/line: it is a modification of the plan-
ing mac/zine: the tool is attached to the end of a
horizontal bar, which is moved to and fro, so as to
plane with short transverse strokes a piece of work,
fixed on a complex adjusting bed or turntable so as
to receive the action of the tool.
SHARPENING. See CUrLnnY—Honn.
SHEARS, are cutting edges used in pairs, and on
opposite sides of the material to be cut, sheared, or
severed. In some cases shears are formed after the
manner of pincers and pliers, or as two double-ended
levers united at the fulcrum by a pin. Scissors are
described under CUrLnnY. The largest kind of
shears, such as are used for dividing bars of iron, 4:, 5,
or 6 inches wide, and 1 to 2 inches thick, are described
under IRON, Fig. 12411. Shears in which the cutting
edges are in two parts not united by a pin, are shown
under NAILS, Fig. 14941. See also PAPER, Fig.
1580, &c.
SHEATHING. See SHIP.
SHEET-METAL WORKS. See RAISED Wonxs
in METAL.
SHEEI‘ING PILE. See BRIDGE. Sect. III. Figs.
282, 283.
SHELL. The protective covering of a class of
animals widely distributed throughout the earth, the
fresh waters, and the ocean. This covering is in
most cases exterior, and large enough to enclose the
whole body; but in some cases it is interior, and only
of sullicient size to protect the heart and lungs. Shell
is a secretion from the skin which covers the back of
the animal, and which is of a peculiar thickness and
fleshy consistence, and is called the mantle. This
fleshy mantle is very evident on the back of the
common grey slug, in which it covers only a portion
of the body, and contains in general, within its sub-
stance, an internal shell, small, flat, transparent, and
oval. The snail affords a familiar instance of an
external shell.
Shells are called nnivnlne or bivalve according as
they consist of one part, or of two parts joined together
by a hinge. The snail is univalve, the oyster is
bivalve. Bivalves are inferior in the scale of existence
to nnivalves, both as it respects powers of motion and
organs of sense. The generality of the bivalve shells,
including various oysters, mussels, &c., are termed
naci'eons shells, from nncre, the French for mother-of-
pearl. Their structure and uses in the arts have been
already treated of [See Mornnn-or-PEABL], while the
ornamental employment of shells in general, as illus-
trated in the Great Exhibition, has been noticed in
the Inrnonuoronr EssAY, p. cxxix. It remains there-
fore to speak of the nnivalve shells, and their employ-
ment in the arts. _
Most of the univalve shells are of the character
called porcelanons from their brittleness, translucenee,
60¢
SHELL.
and the resemblance of their fracture to that of per-
celain. But this fracture when examined by the
microscope reveals a structure of thick parallel layers,
usually of a finely fibrous nature, at right angles to
the external surface. Dr. Aikin says that these
fibres are often nothing more than the transverse
section of thin transparent- parallel lamellae, which
when viewed on their bread surfaces often exhibit the
usual natural joints of calcareous spar. The soluble
part of these shells is carbonate of lime, the par-
ticles of which are cemented together with a very
minute proportion of . animal mucus. The hard and
compact nature of such shells, and their generally
smooth surface, prevent their being cut by the ordinary
tools, which are available for the less hard and
frangible nacreous shells: it is therefore necessary to
treat them after the manner of the lapidary, [See
LAPIDARY wonm] with emery, rottenstone, and other
substances harder than the shells themselves. Such
shells generally require rather to be polished than cut,
but where it is necessary to divide them in order to
exhibit their sections, they are operated upon by
means of the slicer with diamond powder. Certain
descriptions of these shells are well adapted for cameo-
cutting, on account of their substance being made up
of differently coloured layers, and also on account of
a difference of hardness and texture in the different
layers, some approaching more nearly to the nature
of nacreous than of porcelanous material. Specimens
of cameo—shells, and of the rude but efficient instru-
ments for cutting them, were shown in the Indian
collection of the Great Exhibition. The shells were
dense, thick, and consisted of three layers of differently
coloured shell material. “ In the Cassia rzg’w each
layer is composed of many very thin plates, in other
words is laminated, the laminae being perpendicular
to the plane of the main layer : each lamina consists
of a series of elongated prismatic cells, adherent by
their long sides. The laminae of the outer and
inner layers are parallel to the lines of growth,
while those of the middle layer are at right angles to
them.” ‘ Several varieties of the genus iS’tromoaav,2
or conch, supply suitable shells for cameo cutting.
The outer layer is nearly colourless, can be operated
upon with steel tools, and may be carved into
smooth and finished forms. Experience has taught
the cameo-cutter to choose the kinds known as the
BzsZZ’s Moat/z, the Black Helmet, the Horned Helmet,
and the Queers Conch, of which the first two are the
best. The art of cameo cutting was confined to Rome
for upwards of forty years, and to Italy until the last
twenty-six years, at which time an Italian began
cutting cameos in Paris, and now upwards of 300
persons are employed in the trade in that city.
About thirty years ago, the total annual number of
shells used in the trade was about 300: the whole of
them were sent from England, and they were worth
30 shillings each in Rome. But so rapid was the
progress of the manufacture when it became more

(1) JURY Rnron'r, p. 164.
(2) The Greek name for a spiral shell, from o'vpofiéw, strobeo, to
twist.

widely diffused, that the following numbers were
given a few years ago, (18417,) by Mr. Gray, as the
consumption of shells in France for this purpose.
Bull's Mouth ....... .. 80,000 average price ls. 801. value 6,4001.


Black Helmet 8,000 -— 5s. 0d. - 1,8006.
Horned Helmet .. 500 —— 2s. 6d. -— 601.
Queen Conch ....... .. 12,000 —— ls. 215d. -- 700i.
100,500 shells. £8,960
The average value of the large cameos made in
Paris, as stated by the same authority, is 6 francs
each, giving a sterling value of 32,0001., and the
value of the small cameos is about 8,0001, giving a
total value of the cameos produced in Paris, in one
year, (184.6,) at 4:0,000L; while at the same time in
England, not more than six persons were employed at
the trade. The Black Helmet, on account of the
advantageous contrast of colour in the layers, pro-
duces very effective cameos, the carved figure of
the white upper layer being strongly relieved by
the dark, almost black ground, supplied by the
second layer. The shell is first cut into pieces
the size of the required cameos, by means of
diamond dust and the slitting mill, or by a blade
of iron or steel fed with emery and water. It is then
carefully shaped into a square, oval or other shape
on the grindstone, and the edges are finished with
oilstone. It is next cemented to a block of wood,
which serves as a handle to be grasped by the artist
while tracing out with a pencil the figure to be cut on
the shell. The pencil mark is followed by a sharp
point, which scratches the desired outline, and this
again by delicate tools of steel wire flattened at the
end and hardened, and by files and gravers, for the
removal of the superfluous portions of the white
enamel. A common darning-needle, fixed in a wooden
handle, forms a useful tool in this very minute and
delicate species of carving. The careful manipulation
necessary in this work can only be acquired by expe-
rience, but there are general rules thus sensibly given
which the learner would do well to remember :—“As
in all other processes of producing form by reduction,
the general shape should be first wrought, with care
to leave every projection rather in excess, to be gra-
dually reduced as the details and finish of the work are
approached. To render the high parts more distinct
during the process of carving, it will be found conve-
nient to mark them slightly with a black-lead pencil.
Throughout the cutting great caution should be ob
served, that in removing the white thickness the dark
ground is not damaged, as the natural surface of the
dark layer is far superior to any that can be given
artificially; indeed, should the ground be broken up
at one part, it would be requisite from its lamellar
structure to remove the entire scale or lamina from
the Whole surface, a process that will be found very
tedious, and much more difficult than the separation
of the white from the black thickness. In order that
the finished cameo may possess a distinct outline at
all points of view, it is desirable to adopt the system
followed in antique cameos, namely, to leave all the
edges of the figure quite square from the ground, and
not gradually rounded down to the dark surface;
SHIP.
605
should this latter method be followed, it will be found
that the outline is in many places undefined owing to
the colour of the white raised figure of the cameo
gradually emerging into that of the dark ground: this
evil is entirely avoided by leaving the edge of the
figure quite square, for the thickness of about 315th
of an inch. The surface of the cameo should be
finished as nearly as possible with the cutting tools,
as all polishing with abrasive powders is liable to
.remove the sharp angles of the figures, and deteriorate
the cameo by leaving the form undefined. When,
however, the work has been finished as smooth as
possible with the cutting tools, the final polish may
be given by a little putty—powder used dry, upon a
moderately stifl‘ tooth-brush, applied with care, and
rather to the dark ground than to the carved sur-
face; this is the concluding process, after which the
cameo is ready for removing from the block prior to
mounting.” 1
The covering of the tortoise does not properly come
under the denomination shell, partaking as it does of
the nature of flora. The manufacture of that sub-
stance into combs has been treated of under Gonna;
some other particulars will be given under Tonrorsn-
SHELL.
SHELL LAC. See LAC.
SHIP. The subject of naval architecture scarcely
comes within the scope of a work devoted to the de-
tails of the useful arts and the principles of civil
engineering. Like architecture, agriculture, and a
few other similar comprehensive subjects, it occupies
- a special place by itself, and requires to be treated of
in a special work. The naval architect bears the
same relation to the civil architect that a ship bears
to a house, or to a large public building stored with
all the necessaries of life, and swarming with a busy
active population; but with this difference, that the
ship is a floating movable structure, forming one of
the connecting links between nations separated by
the ocean. And it is with reference to this function
that the naval architect should bring all his scientific
» skill to bear upon the design of the magnificent struc-
ture which he proposes to build; for as the civil
architect designs his house or building with special
reference to the service it has to perform, so the
naval architect makes the draught of his ship with
the view to ensure the preponderance of certain good
qualities which may vary with the nature and dimen-
sions of the craft.
Ship-building is both a science and an art. It is
a science, inasmuch as it depends on the application
of some of the great principles of nature, which cannot
change: it is an art, inasmuch as it depends on the
application of rules which are liable to constant fluc-
tuation. By the application of scientific principles it
is possible to ensure the attainment of a certain de-
gree of excellence in a ship, and to cause some pecu-
liar property to preponderate in it, such as stability,
speed, 8:0. 3 and also to discover the causes of some
bad quality in a ship, and to apply the proper remedy.

(1) Hcltzapfl‘el, “ Mechanical Manipulation," vol. iii.

On,the other hand, rules are applied where natural
laws are as yet only imperfectly developed, those, for
example, relating to elastic and non-elastic fluids; but
it has been well remarked, that “the form of a ship’s
body need not of necessity remain imperfect because
the curve of the solid of least resistance is unknown,
since enough has resulted from the consideration of
the nature of that solid to prove that, however appli—
cable it might probably be to the navigation of smooth
waters, the perfect solution of the problem of its form
could only be generally desirable to the naval archi-
tect, as contributing to the theoretical perfection of
the science, and would add but little to its practical
utility in its application to vessels which must en-
counter the tremendous powers of the elements in the
open seas.” There are also other questions inti-
mately connected with the resistance of fluids, such
as the comparative fulness of the fore and after bodies
of the ship, the positions, rakes, and proportions of
the masts, the adjustment and the shape of the sails,
the bracing of the yards, &c., which remain to be
determined by comparison, experiment, and induc-
tion, guided by the knowledge of natural laws.
Then, again, the same principles and rules which
apply to ships destined to one kind of service may be
inapplicable to ships of which the service is very dif-
ferent. A ship whose stores are similar in amount
and kind, as in the case of a man-of-war, presents
fewer constructive difficulties than a merchant ship,
where the lading is variable both in quality and kind.
An East lndiaman, on her outward voyage, is immersed
in the water 2 feet deeper than on her homeward
voyage, and the draught of water in a collier is re—
duced at different times 4%, 5, or 6 feet. These
variations greatly affect the stability of the ship, as
the nature and disposition of the lading influence the
position of her centre of gravity. As the ship becomes
lightened she loses in stability, becomes Zaboursome,
and her rolling motion more violent, and the danger
to the seamen greatly increased. Seeing, then, that
under all the different circumstances of lading, the
ship is exposed to the same winds and seas, it evi—
dently requires more art to design a ship intended for
pm'poses of commerce than for those of war.
If, then, the elements of naval construction, or the
theory of ships, cannot, in our present advanced state
of scientific and practical knowledge, be said to be
settled, we shall be less surprised at the imperfec-
tions of the navies of earlier times. The ships of the
nations of antiquity were propelled by oars, and those
first employed by the maritime nations of modern
Europe were galley/s propelled by similar means.
Early in the 15th century large galleys, called car-
mgues, formed part of the navies of France and Spain.
The vessels used by the Venetians at the battle of
Lepanto were termed galeasses .- they were long gal-
leys, with a narrow deck running along each side of
the vessel, on which small cannon were mounted, and
under which the rowers sat. Previous to the reign of
Henry VII. the naval force consisted only of vessels
furnished by the Cinque Ports : they are said to have
been a kind of long galley. But the first ship of the
606
SHlP. i
royal navy, properly so called, was the Great Harry,
constructed by the direction of Henry VII. : his
successor, in 1515, constructed a ship of about 1,000
tons, carrying 122 guns, large and small: this was
the Henry Grace de Diezr : it was better adapted for
show than for use: it is said to have steered badly,
and to have rolled incessantly: it only made one
voyage. A similar vessel, the Gar-wean, constructed
by Francis 1. of France, was not more successful.
To Henry VIII. belongs the merit of forming the
dockyards at Deptford, Woolwich, and Portsmouth,
and organizing the Admiralty and Navy Boards. From
this reign the navy began to increase in power, and
at the death of Elizabeth it consisted of 42 ships of
war. In 1610, under James I., the Prince, 64: guns
and 1,400 tons burthen, was built, the largest ship
up to that time: and under Charles I. was constructed
the Sovereign qf tire Seas, which carried upwards of
106 guns small and great: her length was 128 feet,
and her breadth 48 feet. The ships of this period
were formed with very high hulls, while the lower
guns were not more than 3 feet above the water;
consequently the ship heeled considerably, and the
lower ports could not be used when the waves ran
high. But the rivalry between England and the
United Provinces in the 17th century, and the desire
of Louis XIV. to make the navy of France at least
equal to that of his neighbours, led to the construction
of ships capable of carrying guns of larger calibre than
had previously been used at sea. In this and the
18th century, naval architecture was studied with
much zeal and success in France and elsewhere, and
the result has been the production of some noble
treatises by such men as the Bernoullis, Euler,
(Scientia Navalis, 17 A9 and 1772;) Bouguer, (Traité
du Navire, 17116 5) Don George Juan, (Examen Ma-
ritimo, Madrid, 1771,) and Chapman, Naval Architect
to the king of Sweden, whose work, published in 1775,
was translated into French by Clairbois, the author
of an “Essai sur l’Architecture Navale, 1776,” and
into English by Dr. Inman, Professor at the Royal
Naval College. Duhamel has also a treatise, entitled
“ Elémens de l’Architecture Navale.” With all this
activity on the part of continental writers, it may well
excite our regret that England, whose very existence,
as an independent nation, depends on the superiority
of her navy, as her commerce does on that of her mer-
cantile marine, should have so entirely neglected the
study of the higher branches of the art as to be re-
duced to the humiliating necessity of copying the
ships which her brave seamen had captured from her
great rival. This servile plan was carried to such an
extent that instructions were actually published for
“taking the form of a ship when built.” Mr. Peake
introduces his description of the method of taking the
form of a ship with the following remarks :—“ The cir-
cumstance of many ships during the last war being cap-
tured from the ehemy, of whose form no draught or
drawing was in possession of the captors, and their
good sailing qualities being such as to make them a
desirable guide for English naval construction, it was
the practice to have such vessels placed in a dry dock

and their forms taken oh by a draughtsman, and a
drawing upon the usual scale made of them.” Eng-
land has not produced one original scientific treatise
on naval architecture, but only a few detached papers
by Mr. Attwood, Dr. Young, and others. In 1754‘.
a practical treatise by Mungo Murray, a working
shipwright at Deptford, attracted some attention.
There are also similar treatises by Hutchinson, Stal-
kart, and others.‘ Attempts have been made, from
time to time, to remedy this theoretical ignorance.
Thus, in 17 91, a Society was formed in London “for
the Improvement of Naval Architecture :” prizes
were offered by this Society for the best papers on the
resistance of fluids, on designs for vessels, on the
proportions of masts, &c. In 1811, a school, under
the superintendence of Dr. Inman, was attached to
the Naval College at Portsmouth, for instructing
young men in those branches of science which relate
to naval afi‘airs, and also in the mechanical operations
required in building a ship. The praiseworthy object
of this undertaking was to introduce into the national
dockyards a better and more skilful description of
shipwright officers, for which purpose the students,
on the expiration of their apprenticeship, if properly
qualified, were to be eligible to all situations in the
ship-building department, and if there were no vacan-
cies they were to be employed in the royal yards as
supernumeraries until vacancies should occur. We
regret to say that this promising experiment has com-
pletely failed : either from the jealousy of the officers
filling stations in the dockyards, being inferior in edu-
cation to the pupils of the school, or from some other
cause, very few appointments were made, and the
supernumeraries were allowed to remain as such, ex-
ercising some influence, let us hope, although in an
inferior capacity, in diffusing a knowledge of the true
principles of their art. The School of Naval Archi-
tecture was abolished in 1832, so that after the lapse
of nearly half a century, the Report of the Board of
Naval Revision made in 1806 still applies, viz. that
“ nothing can be more surprising than that, in a nation
so enlightened as this is, and whose power, import-
ance, and even safety, depend on its naval superiority,
matters so essential to the preservation of that supe-
riority should so long have been neglected.”
The most essential conditions required in a ship

(1) There is also a “History of Marine Architecture” by
Charnock. Also the “Elements and Practice of Naval Architec-
ture,” by John Knowles, accompanied by a folio atlas of plates.
“ The Naval Architect’s Portfolio,” by Lieut. H. A. Summerfeldt,
of the Royal Norwegian Navy. There is also a treatise on naval
architecture, in Rees’s Cyclopaedia, accompanied by numerous
copper-plate engravings; but perhaps the best among the modern
treatises is that in the last edition of the Encyclopaedia Britannica.
There is a short but comprehensive article on the theory of the
Ship and on the Practice of Ship-building in the Penny Cyclo-
padia; but the cheapest and most accessible treatise is that
published in Weale’s Rudimentary Series, entitled, “ Rudiments
of Naval Architecture,” &c., by James Peake, Assistant Master
shipwright, H. M. Dockyard, Woolwich, and formerly of the
School of Naval Architecture, H. M. Dockyard, Portsmouth.
Parts II. and 111., published separately, contain the “Practice
of Ship-building.” There is also in the same series, and in-
tended as a supplement to Mr. Peake’s excellent little work, a
“Rudimentary Treatise on Masting, Mast-Making, and Rigging
of Ships,” 8w, by Robert Kipping, N. A.
.snir.
607
are, that it shall conveniently car-13y its stores, artil-
lery or lading; that it be moved by wind or by steam
with great- velocity; and that it readily obey the
motion of the rudder; that it have the proper stability,
so as not to be overturned when acted on by the wind
and waves, and that its rolling or pitching be attended
with as little strain to the timbers as possible. Some
of these qualities are inconsistent with each other, so
that the architect has to find a construction such as
will allow the quality most required to be fully ob-
tained, without too great a sacrifice of other desirable
qualities. The form which probably unites the several
qualities in the highest degree is thus described :—
“ The body of a ship about its middle has nearly the
form of a portion of a hollow cylinder, with its axis
horizontal and its convex surface downwards. Above
the surface of the water on which it floats, the sides
are curved, so as ‘at the head to have, in a horizontal
direction, the form of a Gothic arch more or less acute.
The breadth diminishes gradually towards the stern,
which above water is either a plane surface nearly per—
pendicular to the ship’s length, or, according to Sir
Robert Sepping’s construction, curved so as to have
in a horizontal section nearly the form of a semi-
ellipse. Below the surface of the water the body of
the ship is curved in ahorizontal direction towards the
head and stern, so as to terminate at those places in
angles which diminish from that surface downwards 5
and thus a vertical section, talcen perpendicularly to
the length of the ship, at some distance from the
middle, towards either extremity, presents on each side
the form of a curve of contrary flexure.”
In merchant ships, great capacity is often of
more importance than velocity in sailing, and hence
in such ships the relations between the length, breadth,
and depth depend less on hydrodynamical principles
than in ships of war.
The theory of a ship depends upon very simple
principles, such, for example, as that involved in the
proposition that a body floating at rest upon a fluid
also at rest, displaces as much of the fluid as is equal
to the weight of the body. Thus the weight of the
water displaced by a ship floating on it at rest, is
equal to the weight of the ship and all its contents.
The weight of the volume of water which would fill
the space occupied by the ship below the general sur-
face of the water on which she floats is called the
displacement. To obtain the total weight of the ship,
therefore, all that is necessary is to ascertain the
weight of this volume of water. Now, it has been
found by calculation that the number of cubic feet in
a homogeneous solid, is equal‘ in bulk to that part of
the body below the’ surface of the water; multiply
this number by the sp. gr. of the water, i. e. by the
weight of 1 cubic foot, the result will be the weight
of water displaced, and consequently also that of the
shi ). '
lllow the ship must evidently not be so far immersed
in the water as to render the armament of a war-
vessel, or the lading of a merchantman, oppressive.
The bulk of a ship is in proportion to her length, her
breadth, and her depth, and this serves as a guide to

her proportions when the displacement is known.‘ The
next step is to delineate the form and area of the
transverse vertical section at the largest part of the
ship’s body, generally extending from the middle of
the length for some distance towards each extremity:
this is the midship section, and on its area principally
depends the direct resistance which the vessel will ex-
perience, while the stability or resistance to inclina-
tion, and the easiness or uneasiness of her motions, are
greatly dependent on her form. The next point is to
determine the area and form of a horizontal section at
the surface of the water, called the load-water section,
or plane ofjlolalioa. On this greatly depends the
stability of the ship in proportion to her dimensions.
Her depth in the water, and the shape of the vertical
section through the longitudinal axis of the ship, is
next determined, and then the transverse vertical
section of the body between the midship section and
either extremity of the vessel, generally at parts where
the body is intended to alter materially from the form
of its midship section to that of a more sudden curve
at the extremities.
The principal drawing or draught of a ship consists
of three plans mutually dependent on each other.
They are sectional planes passing through the largest
portions of the ship, and are named the slicer plaza,
Fig. 1950, the lzalf-ln'caclilz plan, Fig. 1951, and the
daily plan, Fig. 1952. The sheer plan is a projection
on a cerlical longitudinal plane dividing the ship into
two equal parts. This plane passes through the
middle line of the vessel, from the middle line of the
stem or fore boundary, to the middle line of the
stern post or after boundary. The half-breadth plan
describes half the widest and longest level section in
the ship, or that of ahorizontal plane passing through
the length of the ship at the height of the greatest
breadth. The body plan describes the largest vertical
and athwart-ship section of the ship: it forms the
boundary of all the other sections delineated within it.
Considering, therefore, the ship as a solid of three
dimensions, the three plans above noticed will depend
upon each other, thus :—
The sheer plan gives the height and length } In which the length
The half—breadth gives the breadth and is common to the
length . . . . . . two.
The sheer plan gives the length and height } In which the height
The body plan gives the breadth and is common to the
height . . . . . . two.
The half-breadth gives the length and In which the breadth
breadth . . } is common to the
The body plan gives the height and breadth two.
‘A
The drawings of the required elevations and sec-
tions are usually on a scale of 2}: inch to a foot, and
when these are settled and agreed upon, enlarged
copies of them are made to the full size of the objects
which they represent, and are traced with chalk on the
floor of a room called the moalcl-lqfl. This operation
‘ is termed lag/ing W}; and its object is to supply the
workmen with the exact shape and proper positions of
the principal pieces of timber in the intended ship. If
the floor is sufficiently spacious the ship is laid off in
one length; but the floor is usually equal to half the
length of the largest ship, and of the whole height of
608
SHIP.
Fig. 1952.
the hull in addition. The plan being laid down, the
timber ribs or flames are marked in their proper places,
and pieces of plank, 55‘; inch thick, are cut to the forms
of the timbers ; these are called moulds, and they
,serve as patterns for cutting, or converting the timber,
certain marks being made on the moulds to indicate
the directions in which the sides of the timbers are to
be cut.
The principal lines employed in constructing a
draught as well as in laying off a ship are the follow-
ing, viz. z—Wnler lines, which in the sheer plan are
straight lines drawn parallel to the surface of the


Fig. 1950.
a, water lines. I), bow and buttock lines.
SHEER. PLAN.
0, diagonal lines.
147.13. main breadth. can. top breadth.


Fig. 1951.
water, and in the half-
breadth plan they show the
form of the ship by the
successive breadths marked
at heights corresponding
with the water lines in the
sheer plan. These lines are
marked on the practical
drawing in blue ink, and the
upper water line in the half-breadth plan is the line
.of flotation. Level lines: these are similar to water
lines, only they are drawn parallel to the keel in-
stead of the water. It should be observed that
the keel of a ship is not horizontal, or parallel
with the water lines, or plane of flotation, but is
lower towards the stern, in order to allow greater
length to- the rudder, so as to increase its power


BODY PLAN.

HALF—BREADTH PLAN-
in directing the ship’s motion. Diagonal lines show
the boundaries of various sections formed by planes
which are oblique to the vertical longitudinal plane,
and which intersect that plane in straight lines parallel
to the keel. These lines are drawn in red in the body
plan of the draught, where they usually denote the
heads and heels of the timbers. Bnlloe/c and 6020 lines
are the boundaries of the vertical section of the ship
parallel to the vertical longitudinal plane. The main
lreadlis line is the boundary of the widest part of the
ship in each of the three plans. The lop ln'eadl/l, or
lop lz'mlzer line, in the sheer plan, is a line drawn to the
sheer of the ship, fore and aft, at the height of the
underside of the gunwale amidships ; and the lop side
line is a sheer line drawn above the top timber line at
the extreme height of the side of the ship. The culling
down line is a curve in the sheer plan, corresponding


I'I'I'III I
l
.A.
S'_ ell . l ll till in than


Fig. 1953. .eneva'rron or sHIP’s TIMBERS.
to the upper surface of the threats of the floors amid—
ships, and to the under side of the keelson.
The ground on which the ship is built, called the
énz'ldz'ngslip, is situated by the side of a river, or other
water sufficiently deep to receive the ship when she
.is ready to be launched. The ground is arranged in
the form of an inclined plane descending towards the
water. - The first operation is, to place on the slip a
row of blocks of oak, 3 feet high and 4: feet apart, in
the direction of the length of the intended ship, the

upper surfaces of the blocks forming an angle of about
3° with .the horizon. On these blocks is laid the keel
AB, Fig. 1953;’ it is the lowest timber of the ship,
and upon it the whole fabric is raised: it is usually of
elm, a wood which is not injured by immersion in
water; its fibres are tough, and are well adapted to
receive the numerous fastenings or bolts which pass-
through it. In a first-rate man-of-war the size of the
keel is .‘20 inches square. In most ships the keel is
,composed of several ‘pieces of timber scarfed together,
SHIP.
609
as many as 11, 12, or 13 being used in a first-rate,
the after one being of oak. Pieces of elm from 41 to
6 inches thick are worked below the main keel
throughout its whole extent, and form what is called
the false lceel, the object of which is to give the ship
greater immersion to prevent lee-way; and in the
event of the ship grounding in shallow water, the
false keel, by being forced off, may thus free the vessel
from danger. On each extremity of the keel, and
extending towards its middle, timbers called the clearl-
wood are placed, as at o and 1), and the upper surface
of the dead-wood is cut into a curvilinear form 5 b,
with which line the bottom of the ship’s body is made
to coincide. At each extremity of the keel a post is
set up, that at 5 being called the stem—post‘, and that
at s’ the stem-post, which is curved near the bottom.
In large vessels the stem is made up of 3 pieces, known
as the upper, middle, and lower pieces: they are united
to each other and to the fore—end of the keel by
means of scarfs, or with coaks1 and copper bolts.
The scarf, which unites the stem with the keel, is
termed the boxing. See Fig. 1961. The stern-post
is usually of oak, and if timber of sufficient size can
be obtained, it is in one piece, solidity being required
on account of its having to support the rudder. The
W lower end or heel of the stern-post is in-
serted into the after-piece of the keel by
tenons or teeth, fitting into mortices in the
upper and after part of the keel, as shown
in Fig. 1954.‘.
The ribs or flame of the ship
are composed of a large assemblage
of timber, consisting of floors,
cross-pieces, half-floors, floors sllorl and long armed,
first fallacies, secoml futtocks, l/zz'rol fallacies, fom'flz
fallacies, fy‘t/z. falloe/rs, and lap timbers. The sides
and upper portion of the keel and dead-wood are cut
for the reception of the floor timbers, which are
placed across the keel perpendicularly to its length.
The floor timber is shown in section a a e (l, Fig.
1955, e f being the middle line of the ship; and in
order to steady


"I?


Fig. 1954.


a c i it‘in crossing
_ 0
Y2: y e\\ g g g thekeehapiece
, U oftimber called
A &r\\ the rising zoooll,
Fig.1955. g z- ;, 7,, is
worked into the seat of the floor and into the keel,
the points z' and la fitting the upper edge of the
rabbet of the keel. The rising wood is not always
used, the floor being steadied by means of a coak
passed into both the floor and the keel, as at e.
As the economical conversion of the timber is of
importance in so costly a structure as a ship, various
plans have been contrived for arranging the frames.
One plan was to place a half-shift2 or butt on one

(1) For various methods of uniting timbers we must refer to
CARPENTBY—FLOOBS and Pan'rnrous. In the latter article,
Fig. 984 shows the method of joining timbers and preventing them
from slipping upon each other by means of keys or soaks.
(2) The term shift usually refers to a certain arrangement
among the component parts of a ship. Thus, shift of plank, shift
VOL- II.

side of the central line, and a whole shift on the
other, and so on alternately. The plan introduced by
Sir Robert Seppings was, to place a cross-piece or
short floor across the keel, with two timbers or half-
floors meeting at the middle line of the vessel, and
secured to the cross-piece by dowels or circular coaks,
as shown in Figs. 1956, 1957. The timbers which


i HALF FLOOR 5'1, HALF ELOOR l
I CROSS PIECE l
| HALF FLOOR HALE FLOOR I

moss Piece I
Fig. 1956.
‘\ cRoss H1 cmss n!
Q 0 Ocaoss Plies ‘4/:
Fig. 1957.

_///Q
Fig. 1958.

join the cross-pieces or floors are the first futtocks,
dowels or tenons of hard wood being placed in the
heads and heels of the respective pieces, as in Fig.
1958. In merchant ships the first futtocks run down
to the side of the rising 2 2.:
wood or dead-wood, so W;
as to leave what is //
called a water-course of Fig-1959-
the breadth of the keel or of the rising wood, as in
Fig. 1959. The second futtocks are placed on the
heads of the half-floors, and the third futtocks on
the heads of the first futtocks, the fourth futtocks on
the heads of the second futtocks, the fifth futtocks
on the heads of the third, and the top timbers on the
heads of the fourth timbers, and these, with the top
timbers and lengthening timbers, form the flame.
In merchant ships, W
the heads and heels
of consecutive
timbers are united
by choaks, as
shown in Fig.
1960. This plan
favours the econo-
mical conversion of
the timber, the choak supplying the deficiency of the
timber required to form a square butt. It is stated,
however, that the introduction of choaks subjects the
frame to early decay.
The weight of the hull and the strength of the ship
depend greatly upon what is called the room and space,
or the distance between the frames. This varies in
the Queen’s service from 2 feet 6 inches to 3 feet 9
inches. The weight of the hull should be as small as



Fig. 1960.
o
900k



of dead-wood, 8zc. is the disposition of the butts or butt-ends of the
timber or planking. In a more limited sense, the term shift is
the distance apart of two neighbouring butts or scarfs.
RR
610
SHIP.
possible consistently with strength, for the smaller
this weight the less is the displacement, and conse—
quently the resistance to the propelling power of the
sails being diminished, the speed is increased. When
the spars are determined they are marked on the keel
by a long measuring rod called a station, or room and
spar-ca emf; and the various timbers of each frame as
they are built up are kept at the stipulated distance
from the timbers of the contiguous‘ frames. The tim—
bers of the frames above the surface of the water are
nearly rectilinear, but below that plane they are of
various curvatures, being at bottom nearly the form
of a semicircle about the middle of the ship, while
towards the head and stern they form curves of con-
trary flexure, uniting on the keel, with their lower
concavities towards the exterior of the ship.
Within the stem is a timber called the apron, Fig.
1961. It is a continuation of the fore dead-wood, just
as the stem is a prolongation of the
keel: it strengthens the stem, and
affords wood for the reception of the
plank of the bottom and the heels of
the foremost timbers. As a further
support to the stem, the séemson,
shown in Fig. 1953, is worked in. /





The inner
post is a ___________ /
continuation JV
of the after
d'ead - wood, 'Fiy- 1961-
and forms a foundation for the reception of the plank,
and receives‘the heels of the extreme after timbers.
For the method of raising up the frames, cutting
down the floors, and other particulars, we cannot do
better than refer to Mr. Peake’s instructive little
work. The floor timbers are secured in their places
by the teelsmz y I», Fig. 1962, and H, Fig. 1963: its



Fig. 562. a
form is square, and its siding or width is that of
I the keel la Z: c and d are the heads of the cross-piece,
e the butt of the half-floors placed on one side of the
middle line to allow a coak f to be inserted clear of
the butt 6, while a copper keelson-bolt a b is passed
also on one side of the middle line through the
keelson, cross-piece, and keel. In large ships, 2 addi-
tional keelsons, c, Fig. .1963, called side or sister-
lse'elsorzs, from 30 to 50 feet long, are bolted to the
floor timbers sufliciently near to one another that the
atelier foot of the mainmast may rest upon them.
The timbers of the ship are covered on the outside,
and also partly on the inside, with planks of oak from
3 ‘to 6 inches thick. Th. outer planking is repre-
sented in section, Fig. 1963. The plankingis fastened
to the ribs by means of bolts and trenails, or plugs of
‘1
oak, which. pass through the ship’s side, and are
tightened by means of wedges driven into them at
each extremity. But, before the planking is applied,
the intervals between the frames on either side are '
filled up with pieces of wood 3 inches deep, and as
long as the curvature of the timbers will allow, the
lines of juncture with the timbers being well caulked.
The spaces between the exterior and interior pieces
are also sometimes filled up with cement, at least as
high as the plane of flotation, so that in the event of
the ship striking on a rock, and the outside planking
being torn-off or damaged, the vessel would still float.
This plan, proposed by Sir Robert Seppings, also adds
to the strength of the ship by the introduction of a
solid mass of material below the water-line. “ It is
found in practice,” says Mr. Peake, “from the form
given to the bow and quarters under the water, being
fine or sharp, to ensure velocity in sailing, that these
extreme portions of the ship are not water-borne ;
and that thence the .midship volume displaced must,
to make up the whole displacement or weight, be on
the contrary greater than equivalent to the weights
placed over it. The results which arise from this
inequality between the superincumbent weights and
the upward pressure of the water are practically evi-
denced by the falling of the extremes and the rising
of the middle of the vessel, causing the keel of the
ship, after she has been some time afloat, to assume
a curved form, which is technically called bogging.
To take this altered position in the water, theory
points out, and experience confirms, that the materials
below a certain point in the depth of the vessel must
have been forced into a closer contact with each other,
and that thence the more dense the materials used
and the more perfect their combination in building,
the less alteration there would be in the form of the
vessel when floated.” To produce this firmness of
fabric the openings below the water between the
frames or ribs of the ship were first filled with bricks
and mortar between cants of wood, then with a
cement made of sand and water, or sand and coal-tar ;
but these fillings were found to ‘lead to the decay of
the frame timbers, and were abandoned for sound and
well-seasoned fillings of wood, as above noticed. They
are so arranged as to form a water-course under the
internal planking for the drainage of water arising
from leakage or other cause to the limber passage
along the keel, and pass to the pump-well. These
channels or water—courses are covered with planks or
battens, as shown in Fig. 1963. For merchant ships,
Sir Robert Seppings recommended strakes or courses
of thick planks, extending longitudinally through the
ship along the interior sides of all the ribs, and cover-
ing the abuttings of the futtock pieces in each alternate
rib. The same surveyor also introduced a diagonal
trussing into ships for the purpose of preventing the
arching or hogging already noticed, but this diagonal
framing was found to be of no great value as a truss ;
it interfered with the stowage in the hold; and was
subject to early decay, inasmuch as old~ship timber
was used for the purpose. As a substitute for this
plan iron plates were introduced for tying the frame
SHIP.
611
timbers to each other, and they still continue in use.
They vary in size from g to 1.‘; inch in thickness, and
from 3 to 6 inches in width: and they sometimes ex-
tend in length from within a short distance of the
keelson to the top~sides or upper part of the vessel.
The beams B B, Fig. 1963, which receive the decks or
platforms of the ship, are supported at their extremi-




hung to the frame, the holes are all bored and left
open for a time to the draught of air, so that the
juices may be drawn off, and the timbers be well
seasoned. Trenails are used for the fastenings, as
already noticed, although copper bolts have also been
employed.
With respect to the inside planking, the first band
M from the keelson is termed the limber
strz/ees, c, Fig. 1963; but a space is
' left, as already noticed, between the
side of the keelson and the lower
edge of these strakes, to form a
\ 1" gutter for drainage. A rabbet is
taken out of the lower of these
strakes to receive the limber boards,
or plates when of iron, which keep
the dirt of the hold out of the gutter
or limbers, that it may not be drawn
into the pump well, and choke the
pumps. In a large ship there are
usually 3 strakes on each side.


//)
a


I.
Fig. 1963. mmsnrr snc'rrorr.
A, decks or platforms. B, beams. c, waterways.
1), shelf-pieces. E, iron knees. r, strakes.
FH, 1H, 8zc. heads and G, limber strakes. H, keelson.
heels of the frames. I, fillings between the x, keel.
L, false keel. timbers of the frame.
N, wales, or thickest planking.
ties on internal longitudinal ribs called shelves. These
shelves are usually worked before the outside plank-
ing is brought to, and may be regarded as portions of
the internal planking of the frame. And now that the
frame is so far complete, the skinning or planking is
put on, for which purpose the frame is set perpen-
dicular by dropping a plumb-line from the centre of the
cross pauls,1 when the point of the brass or plumb
should coincide with the middle line of the ship,
marked in upon the upper side of the keelson. If it
does not so coincide, the shores are adjusted as re-
quired. The heads or wales are usually of English
oak called llzielcslufi and varying from 4% inches to 10
inches in thickness. As the trees which furnish the
planks are wide at the butts or lower ends, and nar-
row at the top ends, the planks are of a corresponding
form, and are worked lap and tall, as it is called, the
M
Fig. 1964. __
butt of one plank being brought to the top of the
other, so as to make up a constant breadth in two
layers, as shown in Fig.19641. The planks having been



(1) The cross pauls are long pieces of plank with the breadth of
the ship at particular stations marked on them, and secured tothe
timbers at their stations to preserve the form of the ship while in
frame and until the beams are crossed.

M, rough tree nail.
r, bearers for the boilers of a steam vessel.

Next to these are the planks F,
worked over the heads of the floor-
timbers, and the heads of the first
futtocks, to prevent the heads and
heels of these timbers from being
forced in. From 2 to 4 strakes are
placed over each line of heads and
heels in midships, and they are re-
duced in size and number at the fore
and after parts of the vessel.
The beams resemble the rafters of
a house, inasmuch as they support
the floors or decks ; but they do not
act as a tie to the sides of the ship to prevent them
from falling outwards or spreading: on the contrary,
when loaded with weights, such as the guns of aman-
of-war, the decks act as a thrust, tending to force the
sides of the ship outwards. The beams are not flat,
but are set to a rozmrl, or portion of a large circle,
and the decks, when placed on them, partaking of that
round, throw oi the water from them when the ship is
upright, into the side, where holes called seuppers are
placedto convey it away. In small vessels the beams
are formed of one piece of timber; but in larger ships
neither their length nor their width and depth (tech-
MM nically their siding and moulding)
admit of their conversion in one
01,, piece : 2 or 3 pieces are therefore
\ D scarfed together,
‘FF—‘WE the length of the
scarf being %th
the length of the
beam.
The slze‘lfs, Fig.
1965, which re-
ceives the beam-ends, acts as a
sort of internal hoop, and increases
LWMNJ the rigidity of the ship’s frame.
The waterway W, forms a similar
tie above the ends of the beam B, the two being
united by dowels [l e! ’ ; and a bolt, a b, is run
42%’:
4;“
E
‘a
“5
uni,
B
/ Fig. 1965.
i
v: [hen

‘
612
SHIP.
through the shelf, beam-end, and waterway, while
another bolt, e f, is passed through the waterway,
frame-timbers T r, and outside plank P. On gun decks
the curve 0 d of the waterway, was found to interfere
with the training or pointing of the guns, and the
convex curve 0 d was converted into the concave, as
indicated the dotted line. '
The inside planking immediately under the shelf is
called the clamps, and that over the waterways the
spin/selling. To prevent the beam-ends rising off the
shelf-pieces when the vessel is rolling in a sea—way,
the spirketting should be dowelled to the timbers of
the frame : this plan strengthens the waterways which
form the upper abutment of the beam-ends. The space
between the clamps and spirketting is shut in with
thin planking, called s/zorl slafi between the ports
which, according to Seppings’ system, was worked up
as atruss—frame a, Fig. 1966, abutment pieces 6 being






L— V rowan SIDE oF‘s new I i;
5 LPRER CILL CLAMP _ '
as tl I/ 1
2' rowan our. ' i i . j
l sPJRKEl'TlNc A
L WATE RWAY (
Fig. 1966.
worked at the sides of the .ports. In the spaces be-
tween the after ports the truss is reversed in position
as shown at e c.
. The ‘connexion of the waterway, beam, and shelf
with the frame of the ship, as above described, gives
sufiicient‘ strength for merchant vessels, but is not
adequate to the wear and tear of a man—ofwar, loaded
with heavy guns, under a heavy sea or a press of can-
vass. Many plans have been proposed to prevent the
working of the beam-ends from the ship’s sides: iron
fences are commonly used for uniting the beam-ends to
the ship’s sides, and for uniting the two sides of the
ship at the'head and stern; in the cant-bodies, where
the floors or lower timbers do not cross the keel, in-
side'timbers are worked: those in the fore are termed
breast-nooks, and the after ones Wale/les.
The deck beams having been adjusted on the shelves,
the knees worked to them, and the waterways placed
over them, the framing of the deck is the next considera-
tion. Doorways,trap-hatches, and mast-holes have to be
provided for. The mast-holes are of larger diameter than
the masts at their several heights, by double the thick-
ness of the wedge which holds the masts in position,
and these wedges vary in thickness from 3 to 6 inches.
The framing for a mast-hole with wedges consists of
fore and aft parlners, cross parlners, and corner c/zoclas.
The lzaleizwag/s, or doorways from one deck to the
other, are formed of 41 pieces : the two placed fore and
aft are called coamz'ngs, a a, Fig. 1967, and those
athwart-ship head ledges, l 6. The head ledges rest on
the beams, and the coamings have pieces of wood
named earlz'ngs, e, placed under them, and extending
from beam to beam. The ladder ways are framed in
a similar manner, and on the deck, exposed to the
weather, are skylights and framings for the galley or
cooking range, worked in a similar manner. Included

in the‘ framing are'the riding bills, in the fore, for
receiving the cable when the ship is riding by her





anchor. These bitts are placed on the deck immedi—
._..--/-/~/ (\I v
C
(Z
Z 5
a ,1
WW». I A‘ _
Fig. 1967.




l__l of
i Fig. 1968.

lately above the water, such as the lower deck of a
line-of-battle ship and the upper deck of a frigate. In
a merchant vessel the Windlass does the duty of the
capstan and riding bitts.
The use of the waterway has already been explained.
In addition to this there is a plank, called the thin
waterway, 1 inch or- morev thicker than the thickness
of the deck, worked with one edge into a rabbet
formed in the main waterway, the inner edge being
reduced to the thickness of the deck plank. The use


‘ “ll-N E13,’.
5 w Wdrgaway
1%

Fig. 1969.
of the thin waterway is to receive the ' ends of the-
decks as shown in Fig. 1969. The ports, Fig. 196.6,
or oblong holes in the sides, in which the guns are
worked, and out of which they are fired, are closed up
in stormy weather by port-lids, which in large, vessels
close ‘the port-hole in one piece, and are hung with
the hinges ll, Fig. 1970, on the upper side; they are
held up by the ring-bolts
z z, which receive the ____ _ __
port-pendants, or rope, c, ’\
or chain, and when let
down they are secured
on the inside by the
bolts 5 6, and light is
admitted by the illumi-
nator l. But the more
sensible plan is now
adopted of fitting Mr.
Lang’s air-scuttles be-
tween the ports instead of the illuminator. On the
upper deck the ports are in 2 parts: the lower one is
hung with hinges on its lower part, and is called a
bacnlanand the upper part is a lzalfjrorl, to put in
.__-_2 gr.—


Pccéoesl» b1
New 1» 0


Fig. 1970.
. by hand.
SHIP.
613
The joints or seams of the external planking are
made water-tight by forcing into them spun threads
or layers of oakum, formed by picking to pieces old
ropes and cables cut into short pieces termed junk.
The seams of the planking are, if required, opened by
sharp iron wedges, called seeming-irons, which are
driven in by a beetle or mallet. The effect of these
wedges is to close the seams above and below the
seam which is being operated on, and thus bring a
strain on the fastenings of both planks. The oakum
is forced into the joints by means of sharp iron wedges
called caulking-irons, and should any of the planking
be forced ed in this severe operation, the shipwright
puts in additional fastenings before the caulking is
completed. When the stipulated number of threads
of oakum has been forced into the seams, the whole,
is more firmly bedded or korsell up by two men, one of
whom holds, by means of a handle, the mes/ring or
mac/ring iron to the caulked seam, while the other man
drives it in with the beetle. The seams are now payed
with melted pitch, applied by means of small mops;
and, lastly, as high up the bottom of the ship as the
copper sheathing will afterwards come, a thread of
spun-yarn is laid in to make the seam flush or level
with the planking, so that the copper sheathing may
be laid on more smoothly. The bottom of the vessel,
as far as the copper sheathing will extend, is also
nayecl up or covered over with a mixture of pitch and
tar. The decks of the ship are also caulked with
oakum, but the weather decks are payed with marine
glue instead of pitch.1
The ship, being thus made water-tight, is next
launched into the water, for which purpose the slip-
way on which she is built is made in the form of an
inclined plane, and the upper surface of the blocks
l; b, Fig. 1971, which received the keel, and on which
the ship rests during the building, is also inclined;
so that the ship, during her construction, is always

inclined to the horizon gths inch to a foot in her
length, or nearly 1 foot in 19 feet below the horizontal
plane. The weight of the ship (in a 120-gun ship the
hull alone weighs at least 2,600 tons) is now to be
transferred from these blocks to a cradle, or support,
arranged on two inclined planes, or slz'clz'ng wayaclcl, one
on either side of the keel, and so placed on the slip
that the outside of the bilgeways (e e, f j, in the fol-
lowing figures) or foundation of the cradle which sup-
ports the ship during the launching, shall be gth of
the main or greatest breadth of the vessel from the
side of the keel, thereby giving the bilgeways a spread
from the outside of one to the outside of the other of
ad of the main breadth of the ship and the breadth of
the keel in addition. Thus the bilgeways form the
support of the cradle, the cradle is the truck or car~
riage which bears the ship into the water, and the
sliding-ways are the inclined planes down which the
bilgeways slide. The sliding-ways consist of blocks
of wood, on which are laid planks, which form an
'inclined plane about 3 feet 4. inches wide. These
planks are usually laid on the blocks with close joints,
but Mr. Peake recommends them to be kept an inch
apart, otherwise, the air being excluded, a powerful
adhesion takes place between the lower surfaces of
the bilgeways and the upper surfaces of the sliding-
ways. The bilgeways are about gths the length of
the ship, which, for a first-rate of 120 guns, 205 feet
long, would be 170 feet, their breadth and depth being
about 2 feet 6 inches square. Outside the bilgeways
is secured a square piece of fir g, of about 5 inches,
termed a riband, to prevent the bilgeways being forced
outwards by the weight of the ship during the launch-
ing. The foremost piece of riband is of oak, as it
‘forms the abutment of the after end of a piece of
timber called the clog-shore, g, the fore-end of which
butts or stops against large cleats r on the bilgeways,
and these retain the ship on the sliding-ways until the




Fig. 1971.
time for launching. The under side of the cleat r
should be kept above the upper side of the ribands
g, so that in launching the cleat r should pass over
them. A trigger 2f is placed under the dog-shore, and
removed just before the launch. The foremost pieces
of riband are bolted to the sliding-ways, and to pre-

(1) As the caulking tends to stiffen the ship, and to increase
the strain of many of the fastenings, it is sometimes the plan not
to caulk the internal planking until the ship has been some years
at sea.


ARRANGEMENTS FOR THE LAUNCH-
vent the bilgeways being forced inwards, shores s are
placed on cleats from the sides of the keel to the in-
side of the bilgeways. To support the ribands and
prevent them from spreading, riband shores p p are
provided. The amount of inclination to be given to
the sliding-ways is regulated by the size of the ship,
the rise and fall of the tide, and the inclination of the
building-slip. Smaller vessels require most inclina-
tion to be given to the sliding-ways, 1%; inch to a foot
being sometimes required to give an impetus to their
614
SHIP.
comparatively light weight of hull. At the ends of the
bilgeways are holes a for the reception of ropes, which
are led on board the ship so as to secure the bilge-
ways when the vessel is in the water, when the bilge-
ways float up from under her.
The slide beyond the slip is laid during the recess
of the tide, and the bilgeways having been placed in
position under the bottom of the ship, large pieces of
fir z'z', called stopping-up pieces, are placed in the
middle part of the bilgeways so as to meet the bottom
of the ship; but at the fore and after parts poppets
I: /e of square timber are secured, the heads being
confined by a plank bolted to the bottom of the ship,
and furnished with cleats n a screwed to the bottom
of the vessel. The heels of the poppets rest on a
plank, called a sole-piece, Z Z, placed on the upper side
of the bilgeways. The foremost 3 poppets are placed
with their heels forward, so as to act as shores to the
heads of the other fore poppets. The poppets are
united to the stopping-up, which is worked on the
midship portion of the launching cradle by planks m m,
called dagger plants. The ribands g, placed on the
sliding-ways for confining the bilgeways, have a spread
or play greater than that given to the bilgeways. The
bilgeways are usually turned out the day before the
launch, 2'. e. the poppets are taken down, and the
stopping-pieces taken out, and the bilgeways turned
over outwards, leaving their under sides to face the
keel. The upper sides of the sliding-ways, and the
under sides of the bilgeways, are then payed over with
melted tallow, and when this is cold, soft soap or oil
is added in patches. The bilgeways are now turned
in, the cradle is restored and adjusted to the bottom
of the ship, and on the morning of the launch large
wedges 0 0, called slices, are placed inside and outside
the bilgeways, and men, with mauls or large hammers,
are stationed near them. By driving in these wedges
simultaneously, they raise the hull in the cradle, or at
least take its weight from the blocks on which the
after part of the vessel rested during the building:
these blocks thus become loose, and are removed from
under the ship as the tide rises. The fore part of the
cradle is not attached very firmly to the bottom of
the ship; the weight rests partly on the foremost
building blocks, which, as the time for launching ap-
proaches, are split out from under the ship, so that
just before high-water the ship is seen, from aft, sup—
ported on 2 comparatively narrow ribands. The
vessel is then christened, by dashing wine against
her bows or fore part, and the word “Down dog-
shore” being given, the ship glides gracefully into
the waters, destined, let us hope, to assist in diffusing
among the nations of the earth the blessings of peace
and civilization.
The ship is, however, very far from being com-
pleted ; she has yet to receive her copper sheathing,
masts, rigging, &c., which could not be conveniently
applied when on the building-slip, on account of her
height from the ground, the inclination of the keel,
and various other reasons. Moreover, the launching
serves as a good test for the soundness of the naked
planking. For the purpose of sheathing, the vessel

is floated at high-water into dock, [see Doom] and
being placed over the blocks prepared for her recep-
tion, the dock gates are closed, and the water at the
falling of the tide is let out of the dock through
drains or culverts. The vessel is secured by means
of guy ropes and by shores of timber extending from
the sides of the dock to those of the ship, these
shores being gradually added as the tide falls.
It was formerly the practice to cover the immersed
portions of all ships with a thick coating of pitch and
tar; but this did not prevent the deposition of marine
vegetable bodies on the ship’s bottom, which greatly
impeded its way through the water, and afforded but
little protection against the sea-worm. In 1783 the
ships of the Royal Navy were ordered to be sheathed
with copper. The sheets are 4 feet in length by M
inches 5 the lower edges of the upper sheets are made
to lap over the upper edges of those below, and the
after end of each sheet laps over the fore end of the
one following it. The thickness of the sheathing is
denoted by the weights of the superficial foot, such as
32-oz., 28-oz., 18-oz., and 16-oz. The 32-02. copper
sheathing is used round the ship at the height of the
load-water line for a slim/tea or sheets down, and on
the bows down to the keel. Of the whole number of
sheets required it is usual to have %d of 32-02. and
§ds of 28-oz. The 123-02. and 16-oz. sheathing is
usually placed between the main and false keels, to
protect the former from the worm, should the latter
be torn off. Muntz’s metal, noticed under Brmss, is
a cheap substitute for copper sheathing. In a 120-gun
ship 41,4144; sheets of copper are required for the sheath-
ing. The copper is not very durable, and in seas which
contain sulphuretted hydrogen, as on the western coast
of Africa, the corrosion is rapid; as it is also in the
harbour of Marseilles, in consequence of the vast
quantities of soap-waste poured into it from the soap
factories of the town. Sir H. Davy proposed to protect
the copper sheathing by attaching portions of zinc to
the exterior surface, or by securing the copper by
means of zinc-headed nails. A voltaic current would
thus be formed, and the zinc would be dissolved in
preference to the copper. The plan was successful in
protecting the copper; but this being no longer dis-
solved,’ marine animals attached themselves to the
ship in such numbers as to interfere with its sailing,
and the plan was abandoned.
The masts of ships are usually built up of several
pieces : there is a central piece in the form of a poly-
gonal prism, to the sides of which other pieces are
attached, either by means of a longitudinal projection
in each, which is let into a corresponding channel in
the central piece, or by blocks of hard wood let into
the central and the attached pieces. The pieces are
attached together, both in the fore-and-aft and in the
athwart—ship direction, and they are bound together
by iron hoops placed at intervals. It is a good plan
to form one of the surfaces in each of 2 timbers,
which are fitted together in prismatic tables, alter-
nately elevated and depressed, so that the raised parts
in each may fit into the depressed parts of the other.
This arrangement enables the masts to resist the
SHIP.
F6I5
strain of torsion to which they are subject. They
are enabled to resist the pressure of the wind acting in
any direction aft of the beam, by means of the slzroua’s
and basis-slugs, which are secured to the sides of the
ship at the demands, which are always placed rather
aft of the mast; the shrouds can be relaxed or made
z‘ori by means of cleacl-eges. [See BLOCK] The main
and mizen-masts rate or incline aft, but the foremast
is usually upright. The stays assist in keeping the
masts steady, and in resisting the pressure of the
wind when its direction is before the beam, and the
strain produced by the men on the braces. The fore-
stay and the maintopmast-stay are in one line, as are
also the main-stay and the mizentopmast-stay. “ The
stability of a ship depending much on its breadth,
and the lateral action of the wind on the sails being
the force to which the stability is opposed, it follows
that the heights of the masts or sails and that of the
common centre of gravity of the latter, ought to vary
with the breadth of the ship; while the breadths of
the sails must vary with its length. Now the mo-
mentum of the wind in the sails depending upon the
breadth and height of the sails and upon the place of
their centre of gravity, that momentum must vary
with the length of the ship and the square of its
breadth; hence in small ships it is less proportionally
to the stability than in great ships; and on this ac-
count the heights of the masts in the former are
generally less in proportion to the breadth than in
the latter. The rudder serves to govern the ship’s
motion; for on being turned so that its plane is in
a position oblique to the plane of the masts and keel,
the reaction of the water against it as the ship ad-
vances, being resolved in a direction perpendicular
to the last-mentioned plane, becomes a force which
causes the ship to turn upon a line passing through
its centre of gravity. Thus, by giving the rudder
more or less inclination to the said plane, the ship
may be made to move in any required direction, or
may be made to avoid an object by which its safety
might be endangered.”
The term rigging is applied to the general assem-
blage of ropes employed to support the masts, and to
extend or reduce the sails or arrange them so as to
meet the wind. There are various kinds of rigging,
such as standing-rigging, consisting of strands, slugs,
and buele-siags, used for supporting the masts, and
occupying a fixed position in the ship. Running-rigging
consists of traces, slieeis, lialliarels, clue-lines, &c., and
is used for arranging the sails, for which purpose it
is passed through various blocks arranged about the
masts, yards, shrouds, 8:0. The lower rigging is that
used for the lower masts, and the iopr/zasi rigging
includes the topmast shrouds,_ stays, and back-stays.
The class of vessel under consideration is greatly
determined by the arrangement of the masts and rig-
ging. Thus the term ship is applied to those vessels
which have a fore, a main, and a mizen mast, with a
top mast and a lop-gallant mast to each; and in which
the yards in sailing before the wind are braced square,
that is to say, in horizontal positions perpendicular
to the length of the ship : but the mizen sail is usually

in a fore—and-aft position, i. e. in a vertical plane
passing through the keel. If the mizen-mast carr_ies
no top-sail or top gallant sail, the vessel is termed a
turque ,- but in other respects the masts and sails are
similar to those of a ship. A brig has no mizen-mast;
but only a fore and a main-mast, with top and top-
gallant masts and sails like those of a ship: the posi-
tion of the main-sail corresponds with that of the
mizen-sail in a ship with 3 masts. A snow is rigged
in the same manner as a brig, except that the main-
sail is attached to a small mast abaft of, and very near
the main-mast. A schooner has two masts, and the
sails, in their usual position, are in vertical planes,
passing through the keel: it has no top-sails. A sloop
or s/zallop has only one mast with a main-sail, the
plane of which is usually in a fore-and~aft position.
All the above varieties have each a bowsjarii, carrying
a forestay-sail and a jib-sail.
In the British Navy the term line-ofieaille ship is
applied to ships which carry '70 or a greater number
of guns. A frigate has generally 2 decks and carries
from 36 to 60 guns. Frigates are built narrower than
line-of-battle ships in proportion to their length, and
are swift sailers. Ships of war of a lower class than
frigates are termed sloops and oorveiles, carrying from 41
to 20 guns: brigs, ouiiers, briganiines, iteiefies, seliooners
and burgues, none of these carry more than 10 guns.
Vessels are now very frequently constructed of
iron, and they have the advantage of being lighter
and more buoyant than those of wood: they are,
moreover, not so liable to become arched, and the
consequences of striking upon a rock are not so fatal;
for while a vessel of wood might be pierced or go to
pieces, an iron vessel would only be indented. Iron
ships are formed with rib-frames at intervals, and
with longitudinal hoops of iron, and they are covered
with iron plates attached to the ribs by bolts and
rivets. The lower part of the interior is sometimes
divided into separate air-tight compartments, so that,
should the bottom be pierced in any one part, the
water would be confined to that compartment, with-
out endangering the safety of the ship.
With respect to the tonnage of a ship, this is pro-
perly “ an expression for the interior capacity by the
number of tons of sea-water which it could contain;
therefore if the interior volume were found in cubic
feet, on dividing that volume by 35 (the number of
cubic feet of sea-water which are equal in weight to
one ton), the quotient would be the tonnage required.
The tonnage, however, is frequently understood to
express the capacity by the number of tons of sea-
water which might be contained between a horizontal
plane passing through the ship when she floats in still
water with only her equipments and stores on board,
and a horizontal plane passing through the ship when
laden, that is, between what are called the liglzl-waier
and load-neuter planes; the volume of that part of the
ship, expressed in cubic feet, being divided by 35, as
in the other case. This result evidently gives the
weight of the ship’s cargo merely.” 1

(1) Penny Cyclopaedia,—article SnrP.
616
SHOT--SIEVE.
Various formulae have been at different times con-
structed by which an approximate value of the tonnage
may be easily found. Such rules are empirical, but
they are sufficiently accurate for most purposes; and
they greatly abridge the laborious process of finding
the tonnage by the ordinary rules of mensuration.
There are several articles in the course of this
work which bear on the subject of the present article.
The arrangement of lightning-conductors for ships is
described under ELncrnIerrY. Cables are noticed
under CHAIN-CABLE and Born. See also Ancnon—
OOMPASS—BINNACLE—BLOCK, &c.
SHOT. The usual method of making lead shot
resembles in some respects the natural process by
which rain is converted into hail: melted lead is
made to fall through the air from a considerable
elevation, and thus leaden rain becomes cooled and
solidified into leaden hail or shot. The method is
said to have originated with a plumber of Bristol,
named Watts, who, about the year 1782, dreamed
that he was out‘in a shower of rain, that the clouds
rained lead instead of water, and the drops of lead
were perfectlylspherical. He determined to try the
experiment, and accordingly poured some melted lead
from the tower of St. Mary Itedclifie church, into
some water below; the plan succeeded, and he sold
his invention for a large sum of money.
For the carrying out of this invention shot-towers
and shot-wells have been constructed. At the top
of the fall melted lead is poured into a colander, and
the drops are received into a vessel of water below.
In large establishments from two to three tons are
melted at once. The surface of the lead becomes
covered with a spongy crust of oxide, called cream,
which is used to coat over the bottom of the colander,
to prevent the lead from running too rapidly through
the holes, whereby they would form oblong spheroids
instead of spheres. The colanders are hollow hemi-
spheres of sheet iron, about 10 inches in diameter.
The holes differ in different colanders, according to
the size of the shot. For shot known as No. 0, the
holes are 313th of an inch in diameter: for No. 1, the
holes are glg-th in.; for No. 2, 7glgth; for No. 3,
71;,nd; for No. 4., glgth. From No. 5 to No. 9 the
diameter decreases by regular gradations, the latter
being only 3350th of an inch. These dimensions are,
of course, very much smaller than those of the shot
produced; for the lead passes through the holes of
each colander in fine threads, which collect into
globules of the size of the shot on the under surface
of the colander.
When the shot are taken out of the water they are
dried on iron plates heated by steam. The imperfect
shot are then separated by the following process.
A slab of polished iron is tilted at a certain angle,
and the shot are strewed along the upper part of the
inclined plane thus formed. The perfect shot pro-
ceed rapidly in straight lines, and fall into a bin
placed to receive them, about afoot away from the
bottom of the slab. The misshapen shot, on the
contrary, travel with a slower zigzag motion, and fall
without any bound into a bin placed immediately at

- the end of the incline. By this simple contrivance
the good and the bad shot are effectually separated.
The shot are now of a dead silvery-white colour.
They are polished and made dark in an iron barrel,
or ramele, containing a small quantity of powdered
plumbago. They are then tied up in canvass bags
containing 28 lbs. each, and are ready for sale. Iron
shot are formed by casting. The method of forming
leaden bullets is described under GUN.
SIENITE or SYENITE (from Syene, in Egypt).
Granite is so called when it contains hornblende in
place of mica. See Gnanrrn—Inrnonucronr Essay,
page lxxix.
SIEVE. The operation of sifting is a species of
filtration whereby solids of different degrees of fine-
ness are separated from each other, or a solid is
separated from a liquid. Sieves are made of various
materials, but generally of some woven fabric stretched
across a drum: thus there are sieves of horse-hair, of
gauze, of silk, and of wire: there are also sieves of
parchment perforated with holes, as noticed under
GUNPOWDER. Sieves of silk are noticed under
Por'rnnr and PORCELAIN, Sec. V. Wire sieves are
made of different degrees of fineness, according to the
number of wires contained in an inch. Fine sieves
have sometimes as many as 120 wires to the inch.
[See EMERY.] The bolting cylinders, or dressing
machines of corn mills, are a species of sieve. [See
BREAD, Fig. 226.] Sieves are also used for mixing
as well as separating powders; but the particles must
be of such size as to pass freely through the sieve.
The powders being first mingled by hand or by a
spatula, and then passed twice or three times through
a sieve, will be very uniformly mixed.
In those manufactures in which sifting is a fre-
quent and extensive operation, as in the pounding of
drugs, the preparation of emery, &c., a sg'j’lz'ng mac/zine
is a useful contrivance. It consists of a square
wooden frame j, Figs. 1972, 197 3, in which are 5 or 6
octagonal openings for the reception of common drum
sieves ss, which are furnished with covers. The
frame is suspended from the ceiling by means of 4:
'9
\3
w



\\
x


s.- \ l’ _
L .unlllimmii f Q 0

Fig. 1972.
ropes or chains 1* 9*. Motion is given to the frame by
means of a spindle s, Fig. 1973, which works in a
square socket in the bottom of the frame, and is
SILICIUM—SILK.
617
turned by a band 6. By the joint action of the
revolving crank and of the suspending ropes, an
E _
\
0?’ cl


' \s \\\\\ \\\\\
j», \ssssmss
L -


s
‘— ----- "'l
x

“ ‘Ill l — __
l I l
l I“
e " IIHII l l
l
Fzg. 1973.
excentric and jerking motion is thus imparted to the
frame j, and thence to the sieves ss.
SILEX—SILICA. See SILIcIUM.
SILICIUM (Si 15), also called Silicon, is the
metallic or earthy basis of silica, sz'Zea: or flint, a sub-
stance of great importance in the mineral kingdom,
entering as it does into the composition of a vast
number of minerals. Silicium is, next to oxygen, the
most abundant substance on the earth, so far as we
are acquainted with it. In fact, all the rocks which
are not calcareous are siliceous. Silicium occurs in
small quantities in the vegetable, and in extremely
small quantities in the animal kingdom. Silicium
may be obtained without much dilficulty by the
following process :—The double fluoride of silicium
and potassium is to be heated in a glass tube with
nearly its own weight of metallic potassium: a Violent
reaction takes place, and silicium is set free. The
contents of the tube, when cold, are thrown into
water, which removes the saline matter and any
remaining potassium, and leaves the silicium un-
touched. In this state it forms a dark brown powder,
without lustre: on being heated in the air, it burns
and becomes coated with silica: it is acted on by
sulphur and by chlorine: heated strongly in a covered
crucible its colour deepens, and it becomes denser
and incombustible.
The oxide of silicium or silica (Si 03) is said to
contain 213 parts of silicium and 24: of oxygen. The
transparent, colourless varieties of rock crystal con-
sist of nearly pure silica. Quartz, agate, calcedony,
flint, and several other minerals consist chiefly of
silica.
Pure silica may be obtained by the following
process z—Equal parts of fluorspar and glass, both in
fine powder, are to be introduced into a glass flask
together with sulphuric acid. A wide bent tube is
to be fitted to the flask by means of a cork, and the
tube is to be passed down to the bottom of a glass
jar containing sufficient mercury to cover the extremity
of the tube. The is then to be about half filled
with water, and heat applied to the flask. Hydro-
fluoric acid is first disengaged, which in contact with
the powdered glass is decomposed with the production
of water and fluoride of silicium. The latter is a gas,

and escapes from the flask by the bent tube; but
coming in contact with the water it is in its turn
decomposed, and yields silica, which separates in a
gelatinous form, and a double fluoride of silicium, and
hydrogen called hych'cfluosilz'cz'c acid. The silica is
collected on a cloth filter and well washed, then dried
and heated to redness. The acid liquor is a good
test for baryta and potash, with which it forms nearly
insoluble precipitates.
The above process may be varied by collecting the
fluoride of silicium over mercury instead of conduct-
ing it into water: it is a permanent gas, it has no
colour, and is very heavy: when let out into the air,
it forms a thick white cloud, from the condensation of
atmospheric moisture.
Pure silica may also be obtained from powdered
rock crystal or fine sand mixed with about 3 times its
weight of dry carbonate of soda, and fused in a
platinum crucible. A vitreous mass is thus produced,
which when cold is to be boiled with water, which
dissolves it almost entirely. An excess of hydrochloric
acid is added to the filtered liquid, and the whole is
evaporated to dryness. The gelatinous silica thrown
down by the acid is thus made insoluble, and re-
mains behind, when the dry saline mass is treated
with acidulated water, by which the salts of alumina,
sesquioxide of iron, lime, &c., are removed. The
silica is lastly washed, dried, and heated to redness.
Silica is a fine, white, tasteless powder, of the
density of about 2'66. It is not sensibly soluble in
water, or dilute acids, except hydrochloric acid, unless
recently precipitated. It dissolves freely in strong
alkaline solutions; and it can be fused by the oxy-
hydrogen blowpipe.
Silica is really an acid, the silicz'c, and under
favourable circumstances a powerful one 5 but being
insoluble in water, its acid properties are not usually
manifested. When heated with bases, especially
those capable of undergoing fusion, it unites with
them, and forms true salts, which are in some cases
soluble in water; such, for example, as the silicate of
potash and of soda when the proportion of the base is
considerable. The important uses of silica in the arts
will be seen by referring to such articles as Grass—
POTTERY AND PORGELAIN—MORTABS AND Cninnntrs.
See also AGATE—FLINT-—SAND ——QUAnTz, &c.
SILK. The discovery of the uses to which the
cocoon of the silkworm might be applied, appears to
have been first made in China: the written records of
that country declare that an Empress was the first to
unravel the filmy thread, and to work it into a web of
cloth, and this is stated to have taken place 2,7 00
years before the Christian era. However this may be,
it is a fact that when the existence of the silken fabrics
of China became known in other countries, the manu-
facture was not in its infancy and imperfectly executed,
but had attained a degree of excellence which proved
a long and successful practice of it among the Chinese.
Such indeed was its importance, that the very people
and their country are named Seres, and Serz'ca, in
ancient writings, from the Chinese word See, which
signifies Silk.
618
SILK.
While the most imperfect notions were prevalent in
other countries as to the true nature of silk, some
writers describing it as downy wool combed from the
leaves of trees, the material itself in its raw state was
for ages exported from China, and manufactured in
Persia, Tyre, Berytus, and elsewhere, and thus the
woven fabrics reached several parts of Europe and
Asia. The silkworm itself was all this time unknown,
except to the privileged inhabitants of the celestial
empire. Aristotle and Pliny had, however, obtained
tolerably accurate accounts of it. Pliny, indeed, as-
serted it to be a native of Kos, or Cos, one of the
islands of the Grecian Archipelago; yet the fact of
Pamphila, a native of that island, being the first to
unweave imported silken fabrics for the purpose of
spinning and weaving them anew into lighter fabrics,
such as gauze, seems conclusive against his assertion.
This labour of hers would have been unnecessary had
the silken thread been obtainable in any other way.
Her practice was afterwards adopted by the ladies of
Rome. In that luxurious capital, so beautiful a
material as silk only required to be known to be highly
prized. In the reign of Augustus it was very little
known: in the reign of Tiberius silk from the East
was only worn by ladies of the highest rank, but the
thinner manufactures of Cos were more general
during the hot season. Men were forbidden to wear
silken fabrics ; but a mixed material of inferior quality,
called sue serieum, was worn by both sexes. The
great cost and difliculty attending the importation of
silk to Rome, caused Marcus Antoninus, in the second
century, to send ambassadors to China, with a view
of establishing commercial relations with that people ;
but the embassy met with small success, and Rome
continued to be supplied with silk, as before, by the
caravans of Persia, which traversed Asia from the
shores of China to the Syrian coast. The immense
cost of silken fabrics may be estimated by the fact
that a silken garment is mentioned as one of the
wanton prodigalities of the Emperor Heliogabalus,
while a dress of similar material was refused by
Aurelian to his empress, on the ground that it could
only be obtained by its weight in gold.
At length, about the middle of the sixth century, the
western world received the great boon of a supply of
silkworms’ eggs : these were conveyed from China to
Constantinople by two Persian monks, who had gone
to the East as missionaries, and had observed in China
the various processes connected with the rearing of
the silkworm, the nature of the trees on which they
fed, and the preparation of the silk. This occurred
about the year 552, in the reign of Justinian, who
gave every encouragement to the introduction of the
valuable insect. The eggs were secretly conveyed
from China within a hollow cane : at the proper season
they were hatched, and the caterpillars were fed with
the leaves of the wild mulberry-tree. The monks con-
tinued to superintend, at Constantinople, the rearing
of the insects, and the whole process of manufacturing
the silk. From this small commencement the myriads
of silkworms have sprung which throughout Europe
and western Asia have met the demand for silk,

which has gone on increasing from that time to the
present.
The silk manufacture thus commenced was kept in
the hands of the Romans for some years; but the
silkworm was gradually introduced in several parts of
Greece, and the mulberry planted to supply food. The
Greek empire became the great European seat of the
manufacture, and continued to be so for nearly 600
years. At length Roger I. king of Sicily, having in
1147 sacked Corinth, Athens, and Thebes, carried off
large numbers of the inhabitants to Palermo, where
they introduced the culture of the silkworm, and the
manufacture of silk. Thus Sicily became possessed of
this profitable art, which soon made its way into
Italy, so that Venice, Florence, Lucca, and Milan be-
came celebrated for the beauty and extent of their
manufactures in silk. Modena also produced silk,
which, in 1306, was esteemed the best in Lombardy.
In Venice the manufacture was held in such esteem,
that the business of a silk factory was considered to
be no degradation to the higher classes of inhabitants.
The three trades of silk manufacturer, glass-maker,
and druggist were in fact classed together as noble
employments, not unbefitting the aristocracy of Venice.
In the year 1300, many thousand persons were em-
ployed in the manufacture at Florence. Until the
beginning of the sixteenth century Bologna was the
only city of Italy which possessed proper throwing-
mills, so that other cities had to send their silk there
to be twisted and prepared for the weaver. Spain, as
well as Italy, proved very favourable to the culture of
the silkworm. Granada, Murcia and Cordova possessed
numerous establishments for the production of silken
fabrics.
The introduction of silk into France is assigned to
Louis XL, who, in 14180, obtained workmen from
Genoa, Venice, and Florence, and established the
manufacture at Tours. But it did not prosper, so
that in the reign of Francis I. a new importation of
workmen had to be obtained from Milan. These,
about the year 1521, were established at Lyons, and
under the encouragement and protection of the
monarch, obtained much success. The manufacture
flourished, and spread to other parts of France, sup-
plying in the course of time not only the demand of
that kingdom, but a superabundance for foreign mar-
kets. England was largely supplied from thence.
There are evidences of a much earlier use of silk in
England as an ( "casional article of splendid display.
Very soon after t. ' Conquest mention occurs of silken
fabrics; and on the day of the marriage of Margaret,
daughter of Henry III., with Alexander III. of Scot-
land, 1000 English knights appeared in eoz'rzz‘z'sses of
silk, which were replaced on the following day‘ by
others equally splendid. The increased supply and
more general use of silk in England, which followed on
the successful progress of the manufacture in France,
seems to have awakened the alarm of the rulers of
this country, lest home productions should suffer from
this importation of foreign goods. In the reign of
Mary (1554.) a sumptuary law was made, purporting
“that whoever shall wear silk in or upon his or her
SILK.
619
hat, bonnet, or girdle, Scabbard, hose, shoes, or spur-
lcather, shall be imprisoned during three months, and,
forfeit ten pounds.” Magistrates and persons of
‘quality were exempted from this law. In the first
year of James I. it was altogether repealed. But
France was not the only neighbour who tempted
England with these proscribed luxuries. The trade in
silk carried on by the merchants of Antwerp was very
extensive, and yet none of the costly goods were re-
tained for their own wear. “ They buy infinitely,”
says an old writer, “ but it is to sell again. They are
the great masters of Indian spices and Persian silks,
yet wear plain linen and feed upon their 'own fish and
roots. They sell the finest of their own cloths to
France, and buy coarse cloth out of England for their
own wear; they send abroad the best of their own
butter, and buy the cheapest out of Ireland or the
north of England for their own use. In short, they
furnish infinite luxury which they never practise, and
trafiic in pleasures which they never taste.” These
merchants obtained the richest silks, crapes, &c. from
Bologna in return for their own serges; they pro-
.cured the raw, unmanufactured silken produce of
Naples and of Venice in return for cloths, stuffs, and
tapestries, or for jewels and pearls. Milan, Florence,
and Genoa gave them silks, satins, and velvets in
return for pepper, sugar, cloth, and serges. On the
taking of the city of Antwerp by the Duke of Parma,
in 1585, the commerce of the Low Countries was
almost destroyed, and about a third part of the manu-
facturers and dealers in silk took refuge in England,
and gave a powerful impulse to our home manu-
facture.
The silk throwsters of London had formed them-
selves into a fellowship in1562, and were incorporated
in 1629. In 1666, it was stated that no fewer than
410,000 individuals were engaged in the trade. Thus
did the English manufacture steadily progress : while
the importations of foreign silks, with occasional
exceptions, were quite free. Prohibitions were made,
during the reigns of James I., Charles 1., the Pro-
tectorate, and Charles II., but they were not strictly
enforced. In 1685 the revocation of the edict of
Nantes drove hundreds of thousands of industrious
persons from France to seek protection in other
countries: some 50,000 came to England. Of these
the silk manufacturers settled in Spitalfields, and in-
troduced several new branches of their art. At this
time foreign silks were freely admitted, 6 or 700,000
.pounds worth being annually imported; our own
manufacture at the same time was making rapid
advances. But the very circumstance which appeared
for a time so advantageous to the silk trade of
England, namely, the establishment of the refugees
in this country, led at length to monopolies and restric-
tions. In 1692 the refugees obtained a patent, giving
them the exclusive right to manufacture lustrings
and a-la-mozles, the two fashionable silks of that day,
and in 1697, their solicitations were effectual in
obtaining from Parliament a prohibition, not only of
the importation of all French and European manufac-
tured goods, but of those of India and China. From

this period the smuggling of silks from France became
extensive, reaching, it is said, to the value of about
500,000l. per annum; the complaints. of manufac-
turers and the vigilanch of government being wholly
ineffectual to prevent the evil. .
At the commencement of the eighteenth century
the silk machinery of this country was still so defective
that our supply of thrown silk continued to be chiefly
obtained from Italy. An unsuccessful attempt was
made by a person named Crochet to establish silk—
throwing at Derby, but the machinery was not fitted
for its purpose, and the scheme failed. The next
attempt was made by J ohn Lombe, an excellent
mechanic and draughtsman, who visited Italy about
the year 1715 with a view to procure models and
drawings of machines. ‘But he was denied admission
to silk works; and at last obtained his information
by the dishonourable mode of bribing two workmen
connected with a mill in Piedmont, to allow him
secretly to inspect the machinery. The information
gained in these visits was carefully committed to paper
by Lombe each night before he slept. In this way
he obtained all the knowledge he required; but he
and his accomplices were discovered, and could only
with the greatest difficulty and risk to their lives
escape to a ship, which at last brought them all three
to England in 1717. Lombe then erected his famous
silk mill on the Derwent at Derby, which excited
great astonishment at the time. It was 5 stories
high, and ~§th of a mile in length, comprising
26,586 wheels, and 97,746 movements, which worked
‘73,726 yards of organzine silk thread with every
revolution of the water-wheel which moved the
machinery; and as this revolved three times every
minute, the daily produce of organzine amounted to
318,504,960 yards. On the death of John Lombe,
the proprietorship of the mills devolved on his brother
William, and subsequently descended to his cousin
Thomas, afterwards Sir Thomas Lombe, who peti-
tioned Parliament for a renewal of the patent. This
was declined, but a grant of 1a,000l. was made to
him, in consideration of the national benefit derived
from the labours of his family. This benefit was not,
however, very apparent. According to Mr. McCulloch
' these mills could not have been constructed unless
oppressive duties had been laid on thrown or organ»
zine silk; and the circumstance of their having been
erected, and a large amount of capital vested in them,
was successfully urged, for more than a century, as a
reason for continuing the high duties.
From this time the progress of the silk trade may
be traced in the various acts of Parliament framed
with a view to promote its prosperity; but which
seem to have failed in their object. The combinations
and outrages of workpeople, and the dreadful suffer-
ings to which the silk-weavers were occasionally
subjected, show the impolicy of the very severe
restrictions which were laid on this trade. All im
provement was checked: the same loom, and the
same throwing machinery continued to be used, and
in several branches of the manufacture we were far
behind our continental neighbours; when in 1824 the
620
SILK.
‘51100688.
high duty on raw silk'was abandoned for one merely
nominal, and that on thrown silk was reduced nearly
one half. In 1826 the prohibition was removed from
foreign silks, and they were admitted at a duty of 30
per cent. A rapid improvement in our machinery
and manufacture immediately followed this measure,
‘the disparity in the quality of English and French
goods gradually disappeared, and in the year 1842
the value of British silken goods exported to France,
amounted to 181,9241l. The appearance of the goods
produced by our English manufacturers at the Great
Exhibition, proved the great advance made by this
country during the last twenty years in the quality,
design, and cheapness, of our silken fabrics. “Until
within that period,” says the Jury Report, “this
branch of manufacture was comparatively inconsider-
able, but it is now one of great importance, both as
regards the quantity and value of the goods produced,
and the extent of the markets opened for their sale
and consumption.” The silken goods of France in
the Great Exhibition were magnificent and extensive.
The silkworm is the caterpillar of the mulberry-
tre'e moth (Barneys: n'zori) belonging to the tribe of


Fig. 1974. srnxwoarr MOTH AND aces.
mealy-winged nocturnal insects, of which in the
summer evenings we see so many examples. The
eggs of this moth are smaller than‘ grains of mustard-
seed, very numerous, slightly flattened, yellowish at
first, but changing in a few days to a blue or slate
colour. In temperate climates they can be preserved
through the winter without hatching until the time
when the mulberry-tree puts forth its leaves in the
following spring. This tree forms the entire food of
the caterpillar, and seems almost exclusively its own;
for while other trees and vegetables nourish myriads
of insects, the mulberry-tree is seldom attacked by
any but this insect, which in many parts of its native
country, China, inhabits the leaves in the open air,
and goes through all its changes without any atten-
tion from man, whose only care is to gather in the
harvest of silk cocoons at the right season. In some
parts of China, however, the silkworm requires the
‘ same care in the way of shelter, feeding, and nursing
which in other countries is found necessary to ensure
The common mulberry-tree (Moms nip/m),
so well known in Great Britain, is not the best species
for the nourishment of the silkworm, although the
caterpillar feeds readily on the leaves. The white—
fruited mulberry, Ill. alba, a native of China, is the
best, and is greatly preferred by the insect. It is
now cultivated in many parts of Europe, frequently

as a pollard by road sides. It comes into leaf a
fortnight earlier than the black mulberry, which is
an advantage in the culture of silkworms. The
white mulberry does not thrive in Britain, the winters
being too severe. There is another variety of mul-
berry, called the P/zilippine mulberry, which is a
favourite in the south of France, on account of the
size and quantity of the leaves, and the ease with
which it can be propagated.
In the south of Europe mulberry leaves are sold by
weight in the market, and the buyer chooses them
either young or mature, according to the age of the
insects which are to feed on them. Young worms
are fed on tender leaves, while full grown caterpillars
require the stronger nutriment of the mature leaf.
Attempts have been made to store food for the silk-
worm by drying the leaves in the sun, then reducing
them to powder, and placing the latter, in jars. This
powder moistened with water is eaten with avidity
by the silkworm; and may prove a valuable resource
in late seasons, or under circumstances which affect
the principal crop. It is even thought that three or
four crops of cocoons per year may be obtained even
in northern climates, by keeping successive hatchings
of eggs in warm rooms, and supplying the worms with
this food during winter.
The silkworm, when first hatched, is about a quarter
of an inch long, and of a dark colour. If supplied
Fig. 1975. srnxwonm CATERPILLAR. IN SEVERAL sraens
or us enow'rii.
with appropriate food it remains contentedly in one
spot: this is the case throughout its changes, so that
there is no trouble in retaining it within bounds, as
there would be with some other caterpillars. After
8 days’ feeding and rapid increase of size, it prepares
to change its skin, the first skin having become too
small for its body. It remains 3 days without food,
during which time a secretion forms on the surface of
the new skin, which helps the caterpillar to cast off
the old one; but the operation is further facilitated
by silken lines which the insect casts ed and fixes to
the adjacent objects: these hold the old skin tightly,
while the caterpillar creeps out of it. The whole
covering of the body is thus cast off, including that
of the feet, and of the teeth- and jaws, but it is done
with difliculty, and sometimes the skin breaks, and
a portion of it remains attached to the hinder part of
the body, compressing it, and usually causing death.
The newly moulted worm is pale in colour, and
SILK. -
62 I
wrinkled; but it immediately recovers its appetite,
and grows so rapidly that the new skin is soon filled
out, and in 5 days another moult becomes necessary.
Four of these moults and renewals of the skin bring
the caterpillar to its full size, when its appetite be-
comes voracious, and the succulent parts of the mul-
berry—leaves disappear with extraordinary rapidity.
The insect is now nearly 3 inches long; its structure
consists of 12 membranous rings, which contract and
elongate as the body moves. There are 8 pairs of
legs ; the first 3 pairs being covered with a shelly or
scaly substance, which also invests the head. The
mandibles are strong, and indented like a saw. Be-
neath the jaw are 2 small orifices, through which the
insect draws its silken lines. The silk is a fine yellow
transparent gum, secreted in slender vessels, which
are described as being wound, as it were, on 2 spindles
in the stomach; these vessels, if unfolded, would be
about 10 inches long. The insect breathes through
9 pairs of spiracles distributed along the sides of the
body. The caterpillar has 7 small eyes near the mouth;
the 2 spots higher up are not eyes, but portions of
the skull.
Arrived at maturity, the caterpillar is of a rich
golden hue ; it leaves ofl’ eating, and selects a corner
in which to spin its cocoon. It first forms a loose
structure of floss-silk, and then within it the closer
texture of its nest, of an oval shape: here the cater-


F29. 1976. cocoon or srnxwonm, (with part of thefloss-sz'll:
removed.)
pillar remains working until it is gradually lost sight
of within its own beautiful winding-sheet. Taking
no food, and emitting this large quantity of silk, its
body diminishes one-half, and on the completion of its
cocoon it changes its skin once more, but then becomes
an apparently inanimate chrysalis, or aurelia, with
a smooth brown skin,
I I and pointed at one end.
" "ii" - . It remainsin this corpse-
like state for a fortnight
or 3 weeks, when it comes
forth a perfect winged
insect—the silk moth. In


Fig. 197?.
CHRYSALIS OF THE
SILK'WORM.
'escaping from the cocoon it pushes aside the fibres,
first moistening the interior of the cocoon with a
tasteless liquid from its mouth to dissolve the gum
which holds the fibres together. The moth has no
teeth, therefore it cannot gnaw its way out as gene-
rally supposed. In the perfect form, the insect takes
no food, and only lives 2 or 3 days: the female dies
soon after laying her eggs,,and the male does not
long survive her.
The common silkworm is not the only caterpillar

from whose cocoons silk has been obtained for manu—
facturing purposes; but it is so superior in the
quality and quantity of its silk to all other insects,
that small mention is made of any other. The larvae
of many European moths produce a strong silk, and-
the native silkworms of America yield a material
which has been manufactured into handkerchiefs,
stockings, &c. by the inhabitants of Chilpancingo,
Tixtala, and other places of South America. The
ancient Mexicans used the internal layers of white
cocoons, which strongly resemble Chinese paper, as
a material for writing on. A quantity of inferior silk
is obtained in India from the Tusseh and Arindy
silkworms, both natives of Bengal. The first affords
a coarse dark-coloured silk, which is woven into a
cheap durable cloth; the second yields a delicate flossy
silk, which cannot be wound from the cocoons, and is
therefore spun like cotton. Of this, a coarse kind of
white cloth is manufactured, which is loose in texture,
but so durable that it can scarcely be worn out in a‘
life-time.
The domestic treatment of the silkworm has been
brought to great perfection in Italy. Formerly the
eggs were hatched at uncertain periods, depending on
the natural warmth of the season, or they were put
in manure~beds,’or were worn in little bags about the
person next the skin.
apartment heated to the proper degree by a stove;
but they are first washed in water, and afterwards in
wine, to separate light eggs, as well as dirt, and the
gummy envelope which surrounds the heavy ones.
The temperature of the hatching-room is at first
Mo, but is gradually raisedl or 2 degrees daily, until
it reaches 82°, which it is not to exceed. Pieces of
coarse muslin, or of white paper pierced with holes,
are placed over the eggs when they are about to be
hatched. Through these the worms creep to the
upper surface, and are removed as soon as possible to
a cooler place. Young leaves and sprigs of mulberry
are laid upon the muslin or paper, when the worms
eagerly settle on the leaves, and can thus be trans—
ferred to trays, and removed to the nursery. This is
a dry room of regulated warmth, with windows on
both sides, so that free ventilation may be attainable.
Chloride of lime should be in use to purify the air,
and a thermometer and hygrometer to regulate the
heat and moisture; the latter is apt to abound where
silkworms are kept, and is very prejudicial to them.
Moist exhalations arise from the leaves and from their
bodies; fermentation, also, soon takes place if litter
and dung be not speedily removed from their trays;
these are fertile sources of disease among the worms,
and may carry off thousands in a day.
One of the diseases to which silkworms are liable
is of an extraordinary character, consisting of the
formation of a minute cryptogamous plant or mildew
within the body of the living insect. Damp and fer-
menting food and litter produce, in the first place,
among the fatty matter of the body of the caterpillar,
an infinite number of sporules supported by minute
stems. These increase to such a degree that the vege-
tation soon pierces the skin, gives a general mealy
They are now hatched in an-
622
SILK.
appearance to the body of the caterpillar, ripens its
seed, which is borne by the winds to every part of the
nursery, carrying contagion with it, and at length
causes the death of the worm. The dead bodies of
worms or moths (for the insect is infected in all


. .‘1 . . \—. Y _. ‘ , . ¢ \ _ I.
_ _ ‘. . p .x, . _ A _' n. .1
v’ . *‘1 rs ..-~ w,» ‘r’ w’. w.
‘.4 \~ j" > ' ; ‘J\ I ‘- "
Fig. 1978. nunnnw 1N srnxwonms. (Highly magnified.)
stages) are sources of contagion unless immediately
destroyed. This disease is called innseardine in France,
cateinetto in Italy; the French name arises from the
resemblance of the diseased caterpillar to a mealy
kind of sugar-plum made in Provence, and sold by the
name of muscardine; the Italian name also refers to
the chalky or mealy surface of the skin. Various
“ fumigations and washes have been tried, in order to
purify infected nurseries, and to preserve others from
the ravages of this malady: a solution of blue vitriol
(sulphate of copper) applied to the wood-work,
frames, &c. of the nursery is of great use in destroy-
ing the seeds of the fungus, but nothing is so good a
preservative as rigid attention to cleanliness and good
ventilation.
The improved means, first employed in Italy, for
preserving the health of these valuable insects, are
due to Count Dandolo, who gave particular and
scientific attention to the subject, and superseded
many an absurd custom in the rearing of silkworms.
According to his method wicker shelves are arranged
in a room at convenient distances, and are lined with
paper, on which the worms are placed. Such worms
only are placed together as have been hatched at the
same time, ‘the space allowed them being, for each
ounce of eggs, 8 square feet during the first age, 15
feet forlthe second age, 35 feet for the third age,
82% feet for the fourth, and about 200 feet for the
fifth age. The mulberry-leaves are chopped in order
to present a large number of fresh-cut edges to the
young insect. Four meals a-day, as a regular rule,
and luncheons between when the worms are particu-
larly voracious, is the liberal allowance for their sub-
sistence. The temperature at which silkworms are
healthiest appears to be from 68° to 75°, though they
are able to bear a much higher temperature. Alter-
nations of heat_ and cold are exceedingly injurious to
them.
When the silkworms are about to spin they are
. provided with little bushes of broom, heath, or other
flexible substance, which are arranged upright between
the shelves, their to ps'being bent into an arched form
by the shelf above. The bushes are spread out like

fans’, to allow plenty of space for the cocoons; for if
crowded, the worms are apt to form double cocoons,
two working together, and these are worth only half
the price of single cocoons. Specimens of these
bushes,‘ laden with cocoons, appeared in the Great
Exhibition, like diminutive trees bearing golden fruit.
There were also illustrations in abundance of the ad-
vanced state of silk culture in France, and of the
success of a series of systematic attempts which have
been made in that country to improve the breed of
silkworms, and to lessen their liability to disease. The
Central Society of Serieieattare of France exhibited
beautiful specimens of silk, remarkably pure in colour,
strong, and lustrous. In the department of the Dr6me,
where the culture is so extensive that upwards of
3,000,000, of mulberrytrees are required to supply the
food of the myriads of worms, the method of managing
the insects is slightly diflerent from that which we
have described. Instead of wicker shelves lined with
paper, large bamboo-like rushes which grow on the
banks of the Rhone, are cut down, split open, and
attached together so as to form long cane beds about
2% feet broad, called etaies. These are arranged one
above another on a rude framework erected through-
out the chamber, spaces being left at intervals as pas-
sages for the attendants to traverse. The worms, as
soon as they are hatched, are strewed among the
etaies, and the mulberry leaves at the-proper moment
scattered over and amongst them. The attendants
make use of a short ladder to ascend to the higher
etaies. In other establishments the elaies are arranged
so as to hang from the circumference of large wheels
placed at each end of the apartment : by turning these
wheels the ranges of shelves rise and fall, and are
transferred from side to side at the pleasure of the
attendant.
The original improver of silkworm management,
Count Dandolo, has written a volume on the subject,
which has been translated into English, and published
under the auspices of a society called the British, Irish,
and Colonial Silk Company. The labours of this Com-
pany were the last, on an extensive scale, of a series
of attempts made at various times to rear the silk-
worm in these dominions. It was thought that the
introduction into Ireland of an easy and profitable
employment of this description would be of great ad-
vantage to the peasantry of that country. Eighty
acres of land were purchased near Michelstown in the
county of Cork, and planted with nearly 400,000 white
mulberry-trees, which thrived admirably. A small
building was erected for rearing silkworms, and in
spite of the moist and variable climate there would
have been every prospect of success but for the igno-
rance and awkwardness of the peasantry, who had
never been accustomed to any employment which re-
quired so much attention, and who failed in bestowing
on the insects the care necessary to ensure success.
A similar experiment was tried by the Company in
England ‘on a smaller scale. Upwards of 70,000
mulberry-trees were planted near Slough, and pro-
spered there. But after some experience, the Com-
pany renounced the attempt to rear the silkworm in
SILK.
6275*
the United Kingdom, and transferred the whole of
their establishment to Malta. The unskilfulness of
the labourers was also the cause that in America, as
well as in Great Britain, the rearing of silkworms
proved a failure. That it is not impossible to culti-
vate them in cold countries is proved by the fact that
in Sweden, and also in Russia, the culture of the
mulberry and the production of silk is carried on to a
considerable extent. The high price of labour in this
country presents an additional obstacle to the success
of such an undertaking. Favourable results, how-
ever, have been obtained within the last 15 years, at
Newlands, in Hampshire, through the energy and
skill of a lady, Mrs. Whitby, who has planted various
sorts of mulberry-trees, and proved that the dwarf Phi-
lippines are the most advantageous. With these trees,
and a supply of eggs of the large Italian silkworm, she
obtains silk equal in proportionate quantity and quality
to that of Italy and France. Mrs. Whitby has pre-
sented to the Queen 20 yards of rich and brilliant
damask, manufactured from silk raised at Newlands.
British India possesses the climate and the abun-
dance of labour favourable to this undertaking:
accordingly, we find the culture of the silkworm
spreading and improving in that country. In Bengal
there are 8 or 10 principal factories or filatm'es, each
employing from 3,000 to 10,000 persons, and the
results of the Great Exhibition prove the fine quality
of the silk obtained.
The manufacturing treatment of the silk, when the
labours of the silkworm are over, is as follows :—
When the crop of cocoons is complete it is gathered
from the bushes, and about one-sixtieth part is set
aside for the production of eggs, the finest cocoons
as to web and colour being selected for this purpose.
A difference of weight generally determines which are
the cocoons of male, and which of female insects:
the latter are heavier and rounder than the former.
The cocoons intended to produce eggs are preserved
in a very dry room, and in about 10 days they lose in
weight to the amount of 7% per cent.
The main crop of cocoons is next sorted into 9
qualities, known in the factories as—l, Good cocoons,
which are strong, firm, almost equally round at both
ends, not very large, but free from spots. 2. Calcz'rzecl
00000728, in which the worm has died after having com-
pleted its work, and is reduced to a powdery sub-
stance. 3. Cocalorzs, which are larger and less com-
pact than good cocoons. d. C/zoguettes, cocoons in
which the worm has died before finishing its work. 5.
Dzgaz'orz, or double cocoons, difficult to unwind, and
often kept for seed. 6. Souflons, cocoons of so loose
and soft a texture that they cannot be unwound. 7.
Pointed 00000728, in which one end rises in a point,
which breaks off after a little silk has been unwound,
and so spoils the thread. 8. Per/‘brated cocoons, from
which the moth has escaped. 9. Bad citoqaetles, in
which the silk is spotted, rotten, and blackish in
colour. The vitality of the chrysalis is destroyed pre-
viously to unwinding the cocoons : this is done either
by exposure to the sun, or by artificial heat, such as
that of an even after the bread is withdrawn. The

floss silk is removed from the cocoon .by opening it at
one end and slipping out the cocoon. In reeling it is
necessary to use cocoons of one quality, as different
qualities require different treatment.
The natural gum of the cocoons is softened by im-
mersion in warm water, kept at the proper tempera-
ture by a charcoal fire, or by a steam pipe. After
they have remained in it for a few minutes, the reeler
(generally a Woman) gently stirs up or brushes the
cocoons with a short birch-rod, and to this the loose
threads of the cocoons adhere, and are thus drawn out
of the water. They are then taken 4: or 5 together,
twisted with the fingers into one thread (as many as
30 can be wound together) and passed through a
metal loop, which rubs off dirt and impurities; it
then passes on to the reel, which has a slight lateral
motion, so that the thread of one revolution does not
overlay the other. If it were allowed to do so, the
threads would be glued together before the gum had
time to harden by exposure to the air. When any
single thread breaks or comes to an end, its place is
supplied by a new one, that the united thread may be
of equal thickness throughout. The new thread is
merely laid on, and adheres to the rest by its native
gum, and as the filaments are finer near their termi-
nation than at the commencement, it is necessary to
add other cocoons before the first set is quite ex~
hausted. The cocoons are not entirely wound off,
but the husk containing the chrysalis is used, to-
gether with the floss silk, under the name of waste.
Improved methods of reeling are introduced from time
to time, but they are on the same principle as the
above. The length of filament yielded by a single
cocoon is 300 yards, though some have yielded up-
wards of 600 yards. Eleven or twelve pounds of
cocoons yield one pound of silk, from 200 to 250




6"‘ ' 'i'gk
'- "E="="" ‘lid, _ p ._ _
‘f "f . ...‘_;_—- -._V_. a
1;. l1’ , . .2 -__\,,I_'- :~ 72::
a. BOOK OF SILK FROM CHINA. SLIP FROM BENGAL.
c.d. BANKS mom ITALY.
cocoons going to the pound weight: thus about 2,817
cocoons are included in that quantity. The reeled
silk is made up into hanks for sale and use. The
6241
SILK.
form and contents as well as the quality of these
hanks differ according to the quarter whence they are
received, as will be' seen by the figures.
The operations to which raw silk is subjected in
.order to prepare it for weaving or other purposes,
consist chiefly of winding, cleaning, spinning, doubling,
throwing and reeling. When the silk is merely
wound and cleaned it is called dnnzh singles, and is
used in that state for weaving into Bandana handker-
chiefs; and, when bleached, for gauze, and similar
fabrics. If the silk is wound, cleaned and thrown,
it is known as thrown singles, and is used for ribbons
and common silks. If wound, cleaned, doubled, and
thrown, and twisted in one direction, it is called
train, and is used for the woof or shoot of Gros de
Naples, velvets and flowered silks. If wound, cleaned,
spun, doubled and thrown so as to resemble the
strand of a rope, it is called organzine, and is strong
enough to be used for warp. The natural gum of the
silk is for some purposes allowed to remain, in which
case the silk is termed hard; but if this stiffening
gum is removed by scouring, it is termed soft.
In the first operation, that of winding the silk upon
bobbins, each hank is extended upon a light, six-sided
reel, called a swift. A number of these swifts are
arranged side by side upon an axis on either side of
a frame, as shown in Fig. 1980. Above the swifts














\7 ~\_\ @T‘llll ; ] \fi,\\n_\\i\ , ,, “mm mm H mm? nnmnmmn 170' 3.1 IEOTH-m‘fifm'hi‘’ ‘
‘1,, Mir-3. llnwpljillplljjjhqlpplnujiqquu111111111111111111111111uuunmlulllllllllul‘llllll Illlm ‘Y LullllIIilJWH‘lITJI gm pulp-“m I?‘ \lhl‘llllgllulg:
- 1 ' . _
‘w “l” llulnmninnmtilllmifirvi'wwi“ ‘\\\‘.
. 1 >7 ‘ g: >.‘,_ \r A ll‘
\\ '
are the bobbins similarly arranged, one bobbin for
each swift. The bobbins being connected with the
swifts by means of the silken vfilament, are set
in motion, thereby causing the swifts to turn
round and deliver the silk. The hanks vary in size,
and as the dimensions of the swifts require also
to be varied to suit the hanks, the swifts which
are made of laths of lancewood are arranged in pairs
upon a central nave: the outer extremities of each
pair are rather further apart than the inner ends, and
are connected together by a band of small cord on
which the hank of silk rests, so that by slipping the
band nearer to or further from the centre, the size of
the swift can be adapted to the dimensions of the
hank. In putting on the bank the swift must be
balanced, because if one side were heavier than
another, it would in turning, by its sudden fall,
snap the filament. The swifts turn freely in their
supports, but friction is produced by hanging on the

nave a small hoop to which weights are hung; this
prevents the swifts from giving off the silk faster than
it can be taken up by the bobbins. In order to dis-
tribute the filaments equally over the bobbins, each
filament is passed through a small glass ring or eye
attached to a horizontal bar which has a lateral
traverse. The filament is thus wound in a spiral or
oblique direction, which prevents the lateral adhesion
of the filament, and allows its end to be readily found
when it breaks. The winding machine requires con-
stant attendance, in order to
put on the hanks, exchange the
bobbins, and join the ends of
threads broken in winding.
Motion is given to the bobbins
by means of a friction rdller, so
that any one bobbin can be removed without stop—
ping the other bobbins.
The bobbins having been thus filled at the winding
frame are removed to the cleaning or pic/sing machine,
where being fixed horizontally on plain spindles, each
thread is carried from the bobbin over a glass or iron
guide-rod, and then drawn through a brush or cleaner
for the purpose of separating loose dirt; but in order
to get rid of knots and irregularities, the cleaner con-
sists of a bar of metal containing a small notch or
hole capable of adjustment to a certain size. The
filament is dragged from its bobbin through the
cleaner to other bobbins, and should a knot or other
irregularity occur which prevents the filament from
passing through the hole, the plate of metal is de-
pressed and the bobbin is lifted off the friction roller
from which it receives motion, and this stoppage
being noticed by the attendant, she picks out the
mote or removes the knot, so as to allow it to pass
through the cleaner, and then sets the bobbin in
motion as before.
The cleaned filaments of silk are next twisted by
means of the machinery employed in spinning cotton.
Hence the twisting of a continuous filament is called
.1 a


Fig. 1981.







'43-... _ H"; _’ u
i llllllll 'lilllj ill till 1"‘ 1 m
. . a-i ‘ fitters. . . . i
“"l'llllll lull "M1 1' .
gapgmu'rlljul 1,11 hip in‘ lrlllhj lllt ,é‘.’ ,,l l' ‘
'11 ‘jp 1. M" ' I” U‘, : Elr'iu'j:
m 1 1m; mm my,“ , h r‘ 11a - l.
- h e r ' "'. "till;
‘.4:- 3‘ v :-Q -.-“ _I _ .iill: ‘ii ' n ‘ I‘ 1 I _ / ‘ 0/ - ' 6'" / ' 7 / /
Fig. 1982'. SPINNING.
spinning, although it does not resemble the twisting.
together of the short fibres of cotton, flax, or ‘wool,
to which the term is more properly applied, The
bobbins of cleaned silk are mounted on a horizontal
SILK..-
625
axis', and the twisting is eflected by passing the fila- '
ment to other, bobbins placed on vertical axes or'
spindles furnished with flyers, through the eyes of
which the filaments are passed. While the horizontal
bobbins deliver the filamepts at a certain rate,the
flyers rotate at a quicker‘ rate, and thus put twist
into the filaments, and the twist is hard or close in
proportion to the velocity of the flyer.
In the process of douoli'am'a number of filaments
are combined into one cord, the’ strength and dura;
bility of which are thus greatly increased. The
thick cord used for making purses often consists of
30 threads laid side by side and twisted. Doubling
is performed by ‘a woman at a spinning wheel, the
bobbins of thread to be doubled being mounted in a
small frame. She first collects the loose ends from
these bobbins, unites them into one, passes them
through a kind of loop or jack, and attaches them to
a bobbin which is set in motion by the wheel, which
thus unwinds the threads from the bobbins in the
frame, and lays them side by side on the bobbin
attached to the wheel. When a sufficient number of
bobbins are filled the parallel threads are transferred
from them to ‘a horizontal reel, and the ends are
carried through the eye or loop of a rotating flyer, by
the rotation of which the several threads are twisted
or doubled together into a kind of rope. This opera-
tion is called throwing, a term which is sometimes






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Fig. 1983.
DOUBLING, on Trmowmc'.
applied to the whole class of operations by which silk
is prepared for the weaver, .&c. The term appears
to be derived from the rope-maker who throws twist
into his rope. In spinning or doubling, _the' direction
of the twist varies according to the uses to which the
thread is to be applied. In spinning single filaments
the twist is to‘ the right; for train the spinning is
omitted ; after, winding, the threads are doubled, and
then twisted to ‘the right: for organzine, the thread
after being wound is twisted to the left, then doubled
and twisted to the right. These variations modify
the texture of the threads, and adapt them to various
woven fabrics. ,
The doubling frame contains a contrivance for
stopping the bobbin, should any one of the threads
break’. Suppose 2 threads are to be doubled or
twisted together, each thread is passed through an
VOL. II-

eye in a bent wire, which it supports, as shown‘ in
Fig. 1984-; so that should one thread break, the wire
falls down on a‘ lever‘
which it depresses,
and its opposite end
acts as a sort of catch
or' paul to a ratchet-
wheel attached to the
end of the bobbin,
thus stopping its mo-
tion until ‘the attens _
dant has mended the ‘ 1
broken thread.
Some of the heavier \
descriptions of silk
thread, such as sew—
ing, or fringing thread,
are prepared by means
of a flii'osfle frame,
similar in construction to that described under Corron,
Fig. 661. In this, as in the other cases above noticed,
the twisting of the thread is set or made permanent
by exposure to steam, the reels being enclosed for the
purpose in a steam chest. The silk may be sent to
the dyer either in the hard or the soft state. If in
the latter, it is deprived of its gum by boiling it
in soap and water for 3 or 4: hours, about one-fourth
of the weight of the silk being lost in the process,
but this loss is more or less compensated by the
weight of the dye stuff, which sometimes amounts to
12% per cent. This is of importance, as the manufac-
turer estimates the value of his goods by weight.
Silk for ribbons, and some other descriptions of silk
goods, are notiboiled.
The silk after leaving the throwing mill is ready
for weaving into various fabrics either at the common
loom or at the jacquard loom ; it also forms yarn or
thread for hosiery and gloves, and also sewing or
knitting silk. See WEAVING. _
‘The floss silk and the refuse of the throwing pro-
cess‘are worked into yarns for coarser fabrics, such as
shawls and cheap Bandanasf The waste is sent to the
spinner in small balls, which are sorted into parcels
according to their quality. The filaments are next
disentangled by a process of heckling, and they are
laid parallel at the filling engine, where the silk, while

Fig. 1984.
being ‘passed between‘ feeding rollers, is subjected -
to the action of a series of moving combs. .The next
machine is the eli'aioizzg'fmme, in which the filaments
are held firmly in their place by one end, and the
combs travel over-their surface, and remove all im~
purities and short fibres. The latter in their turn are
also dressed, and what remains in the combs is used
for stulfing cushions and similar purposes. The
parallel’ filaments are next cut into lengths of about
an inch and a quarter by a cutting-engine‘, which acts
much like a chaff-cutting machine. These lengths
are then'acted on by- a acute/lei, which converts them
into fine down, which is put into bags and boiled for
an hour or two in soap and water for the purpose of
washing out the gum ; it is next boiled in pure water
to get ridof impurities, and is then submitted to
s s
626
SILKWORM GUT—SILVER.
E
strong pressure in a Bramah press. It is next dried
and again passed through the scutching machine. , It
is lastly carded and formed into yarn by processes
similar to those described under Corron. The
spinning of waste sill; has, however, of late years
undergone several important improvements,» by which
the operations pf cutting, carding, and scutching have
been superseded, the uncut filament being drawn into
a sliver byya modification of the gill used in the pre,
paration of . '
SILKWQRM-GUT- ‘This Substance is prepared
for the angler as follows -_:-.-A number of. the finest
silkworms ‘are selected when they are about to spin:
they are killed by being immersed in strong vinegar,
in which they areileft' for 12 hours closely’ covered up:
should the weather be cool they may be left in the
vinegar 2 or 3 hours longer. When removed there,-
from, and pulled asunder, two transparent yellow?
green cords be observed: this is the silkworm
gut : the other portion of the entrails are of ' a dark,
green colour. If the gut be soft, or break by stretch-
ing, that is an indication that the worm has been
taken out of the vinegar too soon, When the gut is
fit for drawing out, one end is to be dipped into the
vinegar, and the other to be gently stretched to the
required length, and it must be kept extended on a
thin piece of board by inserting its extremities into
slits in the end of the wood, or fastening them to
pins, and in this state it is placed in the sun to dry.
SILVER (Ag. 10.8), a metallic element known
to the ancients, and mentioned in the book of J ob.
It is the whitest of all the metals, and capable of re—
ceiving a lustre which is scarcely inferior to that of
polished steel. In its polished state it reflects more
light and heat than any other metal, so that it has
a very lowradiating power for heat, and hence a silver
vessel retains the heat of the liquid contained in it
longer than a vessel of any other metal. The pre-
ference given to a silver pot for making tea is founded
on correct observation: a black earthenware vessel
is such a powerful radiator of heat, that a hot liquid
contained in it rapidly declines in temperature, and
if used for making tea the temperature of the boiling
water soon falls below the point required for making ‘
the infusion. Silver ranks next to gold in ductility‘ and '
malleability. Its density is 10.427 : it is harder than '
gold and softer than copper, and, when pure, it is so
soft as to be cut by a knife: the addition of a small
quantity of copper increases its hardness ,: it fuses at
a full-red heat, corresponding to 1,87 3° Fahr- Ex-
posed to the heat of a blast furnace, silver throws ofl
metallic vapours, and when fused between the char-
coal electrodes of a powerful voltaic battery it is
readily volatilized. When fused in considerable quan,
tity, the crust allowed to .0001, ad the liquid portion
run off, as explained under BISMUTH, 136, cubic
and octahedral crystals of silver may be obtained.
When fused in open vessels it absorbs oxygen, in
some. cases as much as 22 times its own bulk ; and
in solidifying it expels the gas, probably producing
,; that kind of metallic vegetation which takes place on
-- the surface of silver bnttonswhen suddenly cooled on

the cupel. ‘ When heated to red-ness in contact with
porcelain or glass, the absorbed oxygen forms an
oxide of the metal which, combining with. the silica,
produces a- yellow enamel. At ordinary temperatures
silver is not acted on by oxygen, but it is tarnished
if exposed to an atmosphere containing very minute
portions of sulphuretted hydrogen-gas, which is rea-
dily decomposed by silver. The caustic alkalies do
not act on silver even at a red-heat, and hence the
value of silver crucibles when substances are to be
acted on by caustic potash. Oxide of silver is reduced
by heat alone. Hydrochloric and sulphuric acids do
not readily act on silver, but nitric acid attacks it with
great facility. .Chlorine,..iodin.e, and bromine readily
act. on silver, as was noticed. under Pnoroenarnx.
Silver may be obtained pure by dissolving a piece
of money or of plate (which always contains copper)
in nitric acid, and adding thereto. a solution of common
salt: this throws down the silver in the form of an
insoluble chloride, while the other metals remain in
solution. 100 parts of this chloride are, when
separated and dried, mixed with 70 parts of chalk
and It or 5 of carbon, and this mixture is introduced
into a crucible, and raised to a white heat. Carbonic
oxide is disengaged, and chloride of calcium and
metallic silver remain inthe crucible.
There are ,3 oxides of silver, viz. the suboxide,
AgzO, the protoxide, AgO, and the binoxide, AgOz;
but of these the protoxide only forms permanent and
definite saline combinations, This oxide may be
formed by adding caustic potash to a solution of
nitrate of silver; the pelebrewu precipitate thus
formed is protoxide of silver. Ammonia dissolves it
freely, and? pure water takes up a ‘small portion, form-
ing an alkaline solution. The protoxide of silver
neutralizes acid-s completely, and ferrps salts which
are mostly ccleurless. It decomposed at red heat.
oxygen being evolved and cheesy metallic silver being
left: it partially deeemrieeed by ‘solar light-
Perheps the“ meet ‘important ‘of silver“ is the
nitrate, AgQNQa It isiprepared by dissolving silver
in nitric acid, and evaporating the. solution to dryness,
or until it is sufficiently concentrated to crystallize on
cooling. The crystals are colourless, transparent,
anhydrous tables, soluble in an equal weight of cold,
and in half their weight of, boiling water: they are
also soluble in alcohol._ When heated in a Silver
crucible they fuse like nitre, and like that Substance
are cast into the form of cylindrical sticks, [see Po—
TASSIUM, Fig. 1666,] forming the lunar eaastie of the
surgeon. This salt blackens by exposure to light,
especially if organic matter be present; and it is even
stated that, when the crystals are wrapped in paper,
they are gradually reduced to the metallic state.
Ivory, marble, and other bodies, may be stained black
by soaking them in a solution of this salt and exposing
themto the direct action of the sun's rays. 01.1 616-
count of this property, nitrate of silver is ‘the essential
ingredient in the washes employed £01.‘ dyeing the
hair: it also enters into the composition 9f indelible
ink for marking linen.- The black stain is fiaid '50 9.0.1?
sist of metallic silver. in ‘a- state. off-‘minute ,dtViSiQDQ
SILVER.
627
but it may possibly be the suboxide. Cyanide of
potassium will remove the black stain produced by
any of these preparations of silver. Nitrate of silver
is sometimes taken as a medicine, the effect of which
is, to give to those parts of the body which are ex~
posed to the light a leaden-grey or livid colour, in
consequence of the discoloration of the rele maeosam.
When a stick of phosphorus is introduced into a
solution of nitrate of silver it soon becomes incrustcd
with arborescent crystals of the metal. A plate of
copper also produces a brilliant precipitation of crys-
talline silver. The introduction of mercury into the
solution of nitrate of silver produces a ‘beautiful crys-
talline deposit of silver, known as the arbor Diarzee.
To produce a good effect, the mercury should be
already combined with {,th its weight of silver.
Svlpkale (f silver, AgO,SOg, may be formed by
boiling together metallic silver and sulphuric acid, or
by precipitating a concentrated solution of nitrate of
silver by an alkaline sulphate. It is a white saline
mass, easily fusible. It is soluble in 88 parts of boiling
water, and separates ‘for the most part in a crystalline
form on cooling.
‘Small portions of gold may be separated from large
quantities of silver by heating the alloy, finely gra-
nulated, in sulphuric acid: the gold remains as a
black powder, and the sulphate of silver may be de-
composed by the action of metallic copper: the silver
is precipitated in a pulverulent state, which, with the
assistance of borax or other flux, may be fused and
cast into ingots.
Sulphate of silver forms a crystallizable compound
with ammonia: it is soluble in water, and contains
AgO, SOs-l-QNI-Is.
Hyposalp/iale of silver, AgO, S205+HO, is a crys-
tallizable salt, permanent in the air. The hyposulphite
is insoluble, but it combines with alkaline hyposul-
phites, forming soluble compounds of an intensely
sweet taste.
C’liloride of silver, AgOl, is produced by mingling
together a soluble salt of silver and a soluble chloride.
It forms a white, curdy precipitate, insoluble in water
and nitric acid; but 1 part of this chloride is soluble
in 200 parts of concentrated hydrochloric acid, and
in about 600 parts when diluted with double its
weight of water. Chloride of silver is fusible, and it
cools into a greyish crystalline mass, which cuts like
horn, and when found native is termed hora-silver.
Pure chloride of silver either dry or wet, is slowly
decomposedv by light, and quickly if organic matter be
present. It is also reduced if put into water with
metallic zinc or iron. It is readily soluble in ammonia,
and in a solution of cyanide of potassium. See
Pnoroenarnr. - '~
Iodide of silver, AgI, is a pale yellow insoluble
precipitate formed by adding nitrate of silver to iodide
of potassium: it is insoluble or nearly so in ammonia,
differing in this respect from the silver salts in general.
The bromide of silver resembles the chloride.
Falmina'lirzg silver. When precipitated oxide of
silver is digested in ammonia, a black substance is
produced which is dangerously explosive. It ex-
.heating silver with sulphur.

plodes under water when heated to 212°; it also
explodes when moist by friction with a hard body,
and when. dry the touch of a feather or the vibration
of the house occasioned by the rolling of a carriage in
the street is sufficient to cause it to explode. There
is a similar compound containing oxide of gold. “It
is easy to understand the reason,” ‘says Fownes,
“ why these bodies are subject to such violent and
sudden decomposition by the slightest cause, on the
‘supposition that they contain an oxide of an easily
reducible metal and ammonia; the attraction between
the two constituents of the substance is very feeble,
while that between the oxygen of the one and the
hydrogen of the other is very powerful. The explosion
is caused by the sudden evolution of nitrogen gas
and vapour of water, the metal being set free.”
There is a large demand for silver, not only for the
purposes of coinage, but also for services of plate, for
which it is admirably adapted, inasmuch as it is
not attacked in the slightest degree by any of the
substances used for food. The large demand for the
metal thus occasioned is met by its comparative
abundance in the native state or alloyed with various
other metals; it is alsofound mineralized by the
non-metallic elements, and also in combination with
certain acids. It is also obtained in large quantities
from lead ores, as noticed under LEAD, and in the
‘ Inrnonocronr Essxr, p. xcix. where Mr. Pattinson’s
method of separating silver from argentiferous galcna
is noticed. _
~ll/‘alive silver accompanies the other ores of this
metal, particularly the sulphuret and the chloride: it
occurs either in the crystalline or the arborescent form.
Native silver is also found in amorphous masses, one
of the largest of which is preserved at the Museum of
Copenhagen: it weighs about 50()lbs., and was pro-
cured from the mines of Konigsberg in Norway.
Native silver is often found disseminated in fer-
ruginous rocks, and in the district about Lake
Superior it is found associated with malleable copper.
A compound of silver and mercury, known as native
amalgam, is also found in the form of thin compressed
plates, and also in. crystals.
Silver combines. readily with sulphur, producing a
grey crystallizable sulphuret, much more fusible and
soft than silver. It may be obtained artificially by
Its density varies from
68 to 7. The native sulphuret of silver or vitreous
silver ore occurs in various forms, and when crystallized
is in cubes, octahedra and dodeeahedra. It is of a
shining lead grey colour; its fracture is slightly con-
choidal, inclining to vitreous. It is very fusible, and
being one of the richest and most abundant of the
ores of silver, it supplies a large proportion of the
demand. It is found in Saxony, Bohemia, and
Hungary, and is very abundant in the mines of
Guanaxuato and Zacatecas in Mexico. It is often
associated with the sulphurets of copper, iron, and
antimony. Brittle silver ore is of an iron-grey colour
inclining to black: it is very brittle: sp. gr. 6'2. A
specimen from Freyberg‘ contained silver 66'50, cop-
per and arsenic 0'50, iron 5, antimony 1.0, sulphur 12.
s s 2
628
' SILVER.
Poly/M8276 is another variety’ of brittle‘ sulphuret of
silver. Antimom'al silver is a natural alloy of these
two metals. L‘ncaz'rz'zfc is a silver ore containing
copper and selenium.
One of the richest and most abundant ores of Chili
is the chloride, where it is often accompanied by
native silver. It is found in massive amorphous
fragments associated with the sulphuret, and it also
occurs in small cubical crystals disseminated in the
ferruginous rock known by the name pacos and
collomclos. The colour of this ore is white or yellowish
white, and by exposure to the air it becomes violet.
The fracture is vitreous and conchoidal: it is soft, and
can be scratched by the nail. This ore is of some
what rare occurrence in the mines of Europe. The
iodide of silver also occurs native, as does also the
bromide: the latter ore has been found in large
quantities in the district of Plataros in Mexico, where
it is called plata verde, from the colour imparted by
the bromine. _
' ‘A large proportion of the silver of commerce is
extracted from ores which are too poor to allow of
their being smelted or fused, even supposing fuel
were abundant in the neighbourhood of the mines,
which is not the case. Recourse is therefore had to
the process of amalgamation, founded on the ready
solubility of silver and many other metals in metallic
mercury. The Saxon process as adopted at Freyberg
differs somewhat from the American process. The
argentiferous ores of Saxony consist of sulphurets of
silver combined or mixed with sulphurets of arsenic,‘
antimony, iron, zinc, &c. They should not contain
more than 5 per cent. of lead, and l per cent. of
copper, for these two metals disturb the process of
amalgamation; they unite .with mercury as readily as
silver, and produce a very pasty amalgam. The ores
from the different mines are so mixed, that a ton of
'ore contains from 7 5 to 80 ounces of silver: a certain
proportion of sulphur is also required, and this is
‘usually furnished by the iron pyrites, which on being
roasted furnishes the sulphate and oxide of iron
required for the subsequent process; or sulphate of
iron may be added to the charge.
The ore is spread over a floor 1L0 feet long, and
about 12 wide, and over the charge is sprinkled about
10 per cent. ‘of common sea-salt: the whole is then.
well mixed together, and is divided into small parcels
called roast-posts, each weighing from 3% toll-5 cwts.
Each post is roasted in a reverberatory furnace, in
which the heat is very gradually raised: for the
first 2 hours only a drying heat is used, the charge
being constantly stirred: the heat is then raised
sufficiently to ignite the sulphur and raise the ore to
a red-heat. In about 1t hours the metals at this
temperature become oxidized, and sulphurous acid
gas is given off" rapidly: the ore is prevented from
agglutinating in masses by constant rabbling. The
temperature is now raised, and vapours of chloride of
iron and hydrochloric acid accompany the sulphurous-
acid. The hydrochloric acid arises from the decom—
position of the chloride of iron by theaction of oxy-'
‘gen and aqueous vapour. The last firing is continued

about e} hour,'until'the charge ceases to evolve sull-
phurous acid, its object being to decompose the sea-
salt by the metallic sulphates. The ore now increases
in volume, and assumes a deep brown colour, and the
roasting being complete ‘the charge is raked out, and
when cool is passed through fine sieves for the pur-
pose of separating the powder from the agglutinated
lumps. The latter are broken down, mixed with
a fresh quantity of salt, and roasted again. The
powder is ground to an impalpable state between
heavy mill-stones, and when bolted and dressed, after
the manner of preparing wheat-flour, it is ready for
amalgamating.
The reactions which take place during the roasting
are thus explained by Regnault: l----Tl're sulphurets
of iron and of copper disengage sulphurous acid gas,
and are converted into oxides and sulphates. The
sulphuret of silver, on being heated in contact with
the sulphates of iron and copper, is converted into
sulphate; the copper and the iron being oxidized, give
off sulphurous acid. The sulphates of copper and of
iron, together with the sea-salt, with which they are
mixed, become fused eve-n below a red-heat; and if
the mixture contain sulphuret of silver; a further
amount of sulphurous acid is evolved by the decom-
position of the sulphuretiproduced by the reaction of
its sulphur on the sulphuric acid of the sulphates;
and sulphate of soda, chloride of silver, and chlorides
of copper and of iron, are also formed. If these re-
actions take place in the presence of atmospheric air
the iron is partly converted into sesquioxide, and a
sesquichloride of that metal is also formed. The sul-
phurets of antimony and of arsenic are also oxidized,
so that the roasted mineral may be regarded as'com-
posed of sulphate of soda, chloride of sodium, chlo—
rides of manganese and of lead, sesquichloride of iron
and subchloricle of copper, earthy impurities and
various metallic oxides. '
The amalgamation of the prepared ore is conducted
in wooden barrels BB, Fig. 1985, revolving on iron












ll’ B . .
l ll'illlflllE“ : l'fiillmmlmlllllflfr;
l‘ *l‘l-flllllllllllllrli-Hl ‘' , >-.\~..\\\llllllllll|l|i_;_._§a
l' ‘I .llllllllllllllllll-li t ll? .13 élllllllllllllitq
3‘ "315:". Illiiii ‘ \j_ g- \' _{
isms I ill .1 l‘il‘y-,='_'-t minimum in. [ii till i i l enirmauiaarzr w’ '
l |.'_-u. \n:_ . r lfillllll'lllllllllllllf',31m ‘light-T ‘ pllllllllllillllliu ‘
, ‘,llgnlllllllti'illlll‘ a llfllllr ‘wanna-l
Y llllllllllllllllr: all; amp a. ‘ill a;-
li‘ ‘l:-illlllllllllliltl" nail "rig";
v‘ l .. ill
my, 1985.
axles attached to the ends. Each barrel is 2 feet 10
inches long, and 2 feet 8 inches in internal diameter:
it is made of oak staves, and is strengthened by iron
hoops and binders. A toothed wheel 20 w’ is attached
to one end, which engcges another toothed wheel w
.mounted on an axle A, which is driven by water-power.
Above each barrel is a wooden case 0, Fig. 1986, into

(1) Cours Elémentaire de Cliimie. Tome Troisieme, 1849.—
See also Phillips’s Manual of Metallurgy, published, 1852, in the
new edition of the Encyclopaedia Metropolitana. -
SILVER?
see
which the prepared mineral is thrown, and from this
case proceeds a leather hose Z for passing the pow-
dered ore into the barrel, which is provided for the
purpose with an opening 0, which is plugged with an
iron or wooden screw stopple during the revolution
of the barrel. Above each barrel is also a vessel B,
Fig. 1986, for containing the exact amount of water
required for each charge, and below each barrel is
a trough T for the reception of the charge when the
amalgamation is complete. At the commencement,

Fig. 1986.
3 cwt. of water are run into each barrel: then 10 cwt.
of the powdered ore: to this are added from 7 8 to
100 lbs. of wrought-iron in fragments of about an
inch square and %ths inch thick; and when this is
dissolved a fresh quantity is added. The stopple
being screwed in, the casks are thrown into gear with
the revolving axis A, which rotates about 18 or 20
times per minute. In 2 hours the casks are thrown
out of gear, and the charge examined: if it be found
too firm it is diluted with a small quantity of water;
if too liquid, more powdered ore is added. 5 cwt. of
mercury are now poured into each cask, and the revo-
lution is kept up for 16 or 18 hours, the rotations
being from 20 to 25 per minute. During this time
the charge is examined twice, and water or powdered
ore are added as may be required. The addition of
the mercury produces a rise in temperature: in
winter it may be as much as 104° Fahr. After the
lapse of 20 hours the amalgamation of the silver
is usually complete : the barrels are filled up with
water, and made to rotate 8 times per minute. This
occasions the separation of the amalgam from the
slimy matters with which it was mixed, and enables
it to collect at the bottom of the tuns. The casks
are now thrown out of gear, and the holes 00 are
placed over the troughs 'r'r'. A small peg is re-
moved from the stopple, and the liquid amalgam
flows into the tfough, and the moment any of the
earthy matter begins to appear the hole is closely
stopped. The amalgam is run 05 from the troughs
'r 'r by an iron tube into the gutters a‘ t, which con—
vey it to a receiver. The casks are then turned with ‘

the holes 0 0 upwards, the stopples are removed, and
the muddy residuum is discharged into a spout which
conveys it to reservoirs placed at a lower level. The
ore is found to be deprived of its silver to within
about 5.1, oz. to the ton, and is often subjected to
another amalgamation.
The whole of the above process, including 2 hours
for discharging the casks, occupies about 2% hours.
Every 5 tons of mineral require an expenditure of
15 lbs. of metallic iron and 2 lbs. 12%— oz. of mercury.
The action is as follows :—-Before the introduction of
the mercury the sesquichloride of iron in the ore is
decomposed by the metallic iron, and converted into
protochloride. If the mercury were at once intro~
duced it would by its reaction on the prochloride of
iron become partially converted into protochloride of
mercury or calomel, and'thus occasion loss; but by
first allowing the metallic iron to act, a protochloride
of iron is formed, and this has no action on metallic
mercury. The chloride of silver of the roasted ore is
held in solution by the chloride of sodium, and be-
coming reduced to the metallic state by agitation
with the metallic iron, combines with the mercury in
a liquid amalgam. The chlorides of lead and copper
are decomposed at the same time as the chlorides of
silver, and unite with the amalgam.
When the earthy matters are drawn off from the
casks, the pieces of metallic iron are retained by a
grating, and the slimes are first run into receivers and
then into pug-tubs, where they are stirred up with
water. These tubs have openings at different dis-
tances from the bottom, by which the muddy water
is successively drawn off. A portion of amalgam
collects at the bottom of the vessel, and this is added
to that drawn off from the casks. This amalgam is
filtered through close canvass bags, by which the
liquid mercury is separated from the pasty amalgam.
The latter is a mixture of 6 parts mercury and 1
part of an alloy containing 80 parts silver, and
20 of a mixture of copper, lead, bismuth, antimony,
gold, nickel, zinc, and some other metals. This
mixture is heated in a distillatory furnace, and the
adhering mercury thus got rid of, while the non-
volatile parts of the alloy are obtained in the solid
form. The furnaces at Halsbriicke are well contrived
for condensing the mercury. Beneath the furnaces
are wooden drawers, d d, Figs. 1987, 1988, sliding in
grooves, and supporting an open basin of cast-
iron i ,- these themselves support a wrought-iron
stand a, resting on iron feet a placed within them.
This upright shaft passes through the centre of
5 cup-shaped iron plates, which are placed at dis-
tances of about 5 inches apart, and are destined
to hold the amalgam which is to be operated on.
Over this is lowered, by means of a crane and chain,
a cast-iron bell-shaped dome 1), supported by a
wroughtiron framing and furnished with a loop. A
sheet-iron door r is also employed for the purpose of
closing up the front of the aperture, when the amal-
gam has been placed on the support, and the bell has
been accurately deposited over it. “The total weight
of the balls of ‘amalgam in each furnace usually
630
SILVER.
amounts to about 3 cwt., and after the bell has been
let down over it and the door'c'losed, the basin is
filled with water, and a fire, made with chips‘ of fire-
wood, is lighted on the plate, which has a hole in the
centre, and accurately fits the sides of the bell in the





“in r"
' r _T
. ~ / I
hum .. -
)ff'l’ln’lfilllll/jz ' - -. V_
' 1
'.






Fig. 1988.
part where it is situated. Before closing the door,
it is thickly lined with fire-relay, and the apertures '
existing ‘between it- and the wall are afterwards
securely luted up. When the wood has become
well ignited, the space is gradually-filled up with fuel,
which consists at first of. turf, and afterwards of
charcoal. In this way theebell becomes red-hot,- and
the mercury which is sublime‘d, falls down, and is
collected in the basin, which is constantly supplied
with cold water, through pipes‘ ‘laid “on for that pur-‘p
pose, At the end of 8' hour-s the operation is.
' usually finished, and when no more globules of mer-
cury are heard to drop into the water,‘ .the fire is
allowed to go gradually out.
cooled, the bell is removed by means of a crane, and
the impure silver is taken from the shelves of the
support. The mercury collected the 'basin, is,
after being drained and dried, sent back to the works%
to be again employed in amalgamation, while the
impure silver is refined by fusion, and subsequent
cupellation.” The mercury dust is, ‘from time to.
time, removed from the fume-fines and ground-with the crucibles which have been used in refiningé it is 'Q
then sent to the amalgamation mill. The ‘earthy
residuum from the casks, on being subjected to a
second treatment, yields about 4% oz. of crude Sllvél'f
to the ‘ton, which is ‘mixed with that obtained from
the first process.‘ The liquor run oil’ from the tanks 7
in‘ ,which'the ‘schlich is allowed to subside, contains;
sulphate‘of'sodacommon salt, and sulphate of iron,
with other soluble salts, in small portions. The
earthyl deposits‘ from the second amalgamation con-
tain “silver,- but not enough to pay for a third
\‘v'orki'ng.1 - i -

U \(1)-
account of the amalgamation of copper matts at Mans;
field, ‘and the" Mexican ‘niethodof amalgamation, is ‘given in
Mr‘: Phillipé’s “Manual ofjMetallui-g‘y.” - '
When sufiiciently -

The assay of silver ores and alloys by cupellation,
is noticed under Assume. ' The results obtained
by this method not being perfectly accurate, the
French Government in 1829 appointed a commis-
sion for inquiring into the subject, the result of
which was the adoption of the liquid or humid
method of assay, in which the standard of the alloy of
silverand copper is'determined by means of a solution
of chloride 6f sodium, the strength of which has been
accurately determined. The solution is so regulated
as to strength, that a decilitre thereof will exactly
precipitate 1 of pure silveit In order to
ascertain the "eerie-position of an 1 gramme
thereof is diseol-liie‘di or 6~ grarri'iiiee ("if nitric acid,
and to- this is added from a graduated apparatus, so
much of the solution of common: salt, until no further
_ precipitate of the insoluble chloride 6f silver takes
place. When the point of saturation is nearly attained,
the bottle must be well slfalken after the addition of
each dose of the salt solution, in order that the liquor
may become clear through the precipitation of the
chloride of silver; The whole of the ‘silver being thus
thrown down, the exact quantity of the solution of
common salt employed for the purpose is- read off
from the graduated scale, and this at once indicates
the per centage of silver present. ‘
When the compositien of an alloy is known by
approximation, as in the case of a silver coin or of
a piece of plate,- the ~~ehumid method is not only very
simple, but affords the-most exact results. In such
f a case, two distinct solutions of common salt are~
~used, the first of which, called the normal solution, is
of such a strength, that l decilitre will precipitate
;1 gramme of pure silver." The second, named the
. decimal solution, is only Tl-o-th of the strength of the
first, and is consequently of such a strength, that
' 1 litre of the solution will precipitate 1 gramme of;
: pure silver. »
.Suppose, for example, a piece of silver money of
l the French coinage is to lie-examined, and which, in
,order to be of the legal standard, should contain
T-B-Oggfiths of pure silver; Suppose the-alloy to contain
only Tsg‘z-Gfiths of pure silver, whereby 1'116 gr. of the
mixture would correspond ‘to 1 gm of pure silver.
This quantity is therefore‘ cut off the coin, accurately
: weighed, and put into a bottle which admits of beingv
perfectly closed.- -'by afglass' stopple, and it is dissolved
in from 5 tot grammes of pure. nitric acid. As soon
as the ‘solution is completely effected, 1 decilitre of
‘the normal solution of salt is introduced. If ‘the
alloy be of the standard 18,9060, the ‘whole of the silver
will be precipitated-by the quantity of solution added,

and the supernatant iliquor will contain no traces of‘,
chloride of sodium in excess. But if the standard be
higher-than 1809060, a portion of silver will still‘ remain-
in solution, and if it be below $060 ,- the whole of the
silver will have been completely precipitated, and the


‘liquor will contain an excess of chloride of sodium.
In order to ascertain which result has lJBEILiPl‘O“
duced, .the bottle is carefully closed with its glass
' stopple, and briskly shaken, until the precipitate has
;subsided and the solution become clear. A5 cubic
SILVER.
631 i
centimetre of the decimal solution, capable of
precipitating 0'001 gr. of pure silver, is introduced.
If any silver remain in solution, the liquor becomes
cloudy, and after being again shaken another centi-
metre of the decimal solution is added. If the liquor
again becomes turbid, it is again well shaken, allowed
to become clear, and a third centimetre of the decimal
solution poured in, and so on, until no further cloudi-
ness is produced by the addition of the decimal solu—
tion. Suppose that 5 of the cubic centimetres of the
decimal solution have been introduced in succession,
and have produced a precipitate in the liquor, while
the addition of the sixth has not afiected its trans-
parency, it may be concluded that after the precipi-
tation of 1 gramme of pure silver by the decilitre of
the normal solution, the liquor still contained at least
,O4ooths of a gramme of silver. But as the fifth cubic
centimetre of the decimal solution produced a cloudi-
ness and the sixth did not, it is evident that the liquor
did not contain more than ,osooths of a gramme of
silver, and thus in adding fggoths, the exact result is
certainly attained within one half-thousandth of the
truth. The standard of the alloy in question will thus
be 896+411=900ég thousandths. If, on the contrary,
the decimal solution produce no further precipitate
in the solution of silver which has already received
the decilitre of the normal liquid, the standard of the
alloy is evidently below ,sogo‘ioths. Its exact composi-
tion is ascertained by means of a standard solution of
silver in nitric acid, so adjusted that 1 litre of the
liquor contains exactly I gramme of pure silver: this
is called the cleeirnal solution qf’ silver. In using it, a
cubic centimetre thereof is dropped from a pipette
into the bottle containing the assay, and it occasions
a precipitate of salt exactly corresponding to the same
volume of the decimal solution of common salt which
was added for the purpose of ascertaining if all the
silver were precipitated. The liquor being made clear
by agitation, another cubic centimetre of the silver
solution is added. If cloudiness be produced, the
bottle is again shaken, and a third measure of the
solution introduced, and so on until the silver solution
ceases to produce a precipitate.
cubic centimetres of the silver solution produced a
precipitate, and that the sixth did not, it is probable
that the whole of the fifth was not entirely decom-
posed, and it is usually stated that 41% cubic centi-




metres of the silver solution have decomposed the _
excess of the chloride of sodium left in the liquor after
the addition of the decilitre of the normal solution.
Hence we must subtract 4% thousandths from the
presumed title of the alloy, the correct standard of
which will be expressed by 896 —-— 4.; = 8912;, then-
sandths.
In places where numbers of assays of silver and
copper alloys have to be made, the apparatus is so
arrangedas greatly to assist the operation. The normal
solution is kept in a large vessel of sheet-copper,
tinned on the inside, and supported on a shelf near
the ceiling of the laboratory, as shown at v, Fig. 1989 ;
and to prevent evaporation it is furnished with an
immovable cover, through which passes a tube for the
Suppose the first 5 "

purpose of admitting air to supply the place of the
solution drawn off. A gage g at the side shows, at a
glance, the quantity of the saline solution contained
in the vessel. From near the bottom of the vessel
proceeds a tube l furnished with a stop-cock e. The


l
-
l1
1‘ uunn nm .n


Fig. 1989.
SALT APPARATUS.
pipette P contains exactly a decilitre of the saline
solution, and it is connectedwith the tube l by another
tube l’ containing a thermometer. The metal con-
necting piece, by which the tube l’ is fastened to the
pipette, is furnished with 2 stop-cocks s and s’. In
an assay the operator closes the extremity of the
pipette with the forefinger of the left~hand, and with
the right opens the stop-cocks ss' : the stop-cock s’,
shown separately in Fig. 1989, is so constructed as
to allow the air to escape in proportion as the solu-
tion enters the pipette. When this is filled a little
above the mark re, the cocks s s’ are closed, and the
pipette remains charged with the solution after the
632
SILVER.
finger is removed. Below this apparatus is a sliding
support T, in which is a case of copper b for support-
ing the bottle which contains the solution of the
alloy in nitric acid, and close to it is a small stand
containing a sponge 8 covered with linen and ar-
ranged at the exact height of the beak of the pipette.
The operator slides the plate 12 in the grooves of
the stand T, so that the sponge may be in contact
with the end of the pipette, and by carefully ad-
mitting air through the stop-cock s’, the solution
is allowed to descend until it reaches the mark m
scratched on the glass. The sponge removes the last
drop of the solution which would otherwise be at-
tached to the beak, and as the sponge becomes satu-
rated the solution passes down the hollow stem of a
into the cylindrical vessel beneath. The slide is now
drawn forward until it is stopped by a peg, when the
neck of the bottle 6 will be exactly
under the beak of the pipette: the
stop-cock s’ is now opened, and the
solution flows into the bottle.
When a number of alloys are to be
assayed at the same time, they are
contained in a number of bottles
arranged in a metal frame something
like a cruet-stand, Fig. 1990, and
marked with numbers ; and after the
acid has been added, the stand is placed in hot
water, in order that the heat may promote the solu-
‘ tion. By the side of
l each bottle is a. small
cup for holding the
stopple. When the
solution is completed
the nitrous fumes are
removed from the









L bottles by blowing
‘pun ,_ into them with a
q '1' glass tube, and a


decilitre of the nor-
mal solution of salt
is added to each,
as already noticed.
The bottles are af-
terwards placed in
another metal frame
F, Fig. 1991, sus-
pended from the ex-
tremity of a steel
,, spring s, and steadied
/ villi i; below by an elastic
"a v spring in’ of vul-
canized mdia-rnbber.
iii, The bottles being




Fig. 1991. SHAKING APPARATUS.
Fig. 1992.
closed by their respective stopples and secured in their
several compartments by a kind of collar, Fig. 1992,

which, when thrown up, is supported by a rest a‘, ‘
are well shaken by an assistant, who takes hold of
the handles a it, and moves the whole apparatus
briskly up and down for a few minutes. When the
liquors have become clear the bottles are removed
from this frame to a black table furnished with divi-
sions numbered to correspond with the numbers on
the bottles. The decimal solution, which is con-
tained in a bottle with a pipette passing through
its stopple, is now employed for determining the
exact standard of the various assays. The pipette has
a line drawn on its surface, graduated so as to allow
the operator to measure out 1 cubic centimetre of
the solution. For this purpose the point of the fore-
finger closes' over the upper extremity of the tube,
which is then removed from the bottle, and by the
careful admission of air at the top, the liquid is al-
lowed to drop until it has fallen to the level of the
line marked upon the glass. The top of the tube is
again closely stopped by the finger, and the cubic
centimetre of the solution is transferred to the first
bottle of the series, into which it is allowed to flow
by removing the finger. Each of the other assays
receives the same quantity of the solution. The
bottles are then examined, and a chalk mark is made
on the black table before those bottles which exhibit
precipitates. These are briskly shaken at the shaking
apparatus; returned to the black table, and another
close of the decimal solution is added to each bottle,
in which a precipitate was obtained by the last opera-
tion. In this way the several bottles which give no
precipitate are discovered, and the number of chalk-
marks before each shows the number of cubic centi-
metres of the decimal solution added to each assay.
Half a centimetre is deducted from each to allow for
the loss on the last addition, a portion only of which
has probably been decomposed.
The normal solution of common salt is prepared at
the temperature of 15° Cent. But as the density of
the solution varies with the temperature of the air,
it is necessary to apply certain corrections when the
assays are made at temperature above or below 15° C.
For this purpose the thermometer contained in
the tube 5', Fig. 1989, should be consulted, and the
corrections read off from tables prepared for the pur-
pose; but in order to prevent error, the assayer usu—
ally makes an experiment every morning on the saline
solution with 1 gramme of pure silver, and the indi-
cations thus afforded enable him to ascertain the
exact constitution of the solution, and to correct it
accordingly.
The standard solution of chloride of sodium is
made by dissolving 500 grammes of common salt in
{L litres of water, and filtering. The additional quan-
tity of water required for the normal solution, sup-
posing the salt to be pure, is now added, and the
solution is carefully adjusted to the proper strength
by testing it with the solution of pure silver in nitric
acid. The decimal solution is prepared by pouring
a cubic decilitre of the normal solution into a bottle
of the exact capacity of a litre, and filling it up with
pure distilled water. The decimal solution of silver
‘SILVERl—SIPHONT
“633
is prepared by dissolving 1 gramme of pure silver in
nitric acid, and to this distilled water is added to
make up an exact litre of the liquid.
If the alloy operated on contain mercury or lead,
the results of the humid assay are not exact, since
these metals are precipitated with the silver and
decompose a portion of the normal solution. The
presence of mercury is detected by the difficulty of
obtaining a transparent solution by agitation. Such
being the case the assay is not to be relied on. The
assay of alloys containing mercury may, however, be
conducted by the humid process by adding a solution
of acetate of soda to the nitric acid liquor containing
the silver previously to the introduction of the normal
solution: the acetate prevents the formation of chlo-
ride of mercury.
Professor Graham, of University College, London,
and Professor Miller, of King’s College, conduct the
silver assays for the Royal Mint by the humid pro-
cess. Professor Graham adopts the French system
of weights and measures above described. Professor
Miller has modified it so as to suit English weights
and measures. The following is a brief outline of the
process as conducted by that gentleman, and kindly
communicated by him: 1-—10 grains of the alloy to be
assayed are accurately weighed, and dissolved in 120
grains of pure nitric acid. The standard solution of
salt is so regulated that 1000 grains thereof will
exactly precipitate ] grain of pure silver. Now,
taking the standard of English silver at 925 silver
and 75 copper, care is taken to keep an excess of
silver in the solution, for if salt be in excess, however
small, no amount of shaking will get it clear. Ac-
cordingly the pipette r, Fig. 1989, is charged with
the standard solution to the mark m, which is equi-
valent to 923 grains, a quantity which is capable of
precipitating 923 grains of pure silver: the liquor is
agitated for about a minute, and then allowed to
settle. 10 grains of the decimal solution, capable of
precipitating 1{mth of a grain of silver, are now added:
if a cloud be produced a chalk mark is made against
the bottle. The liquor is agitated for a minute: a
second dose of the decimal solution is added, and if
no precipitate is prodrced, it is thus shown that of
the 10 grains of the alloy 923% grains consist of pure
silver, the rest being alloy; thus showing a result
a little below the standard. The standard solution
of silver is formed by dissolving 10 grains of pure
silver in pure nitric acid, and diluting it so that 1000
grains thereof shall contain 1 grain of silver.
The alloy of silver and copper used for coin and
for the manufacture of silver-plate, is adjusted by the
legislature of the country. In this country the same
alloy is used for both purposes: the standard silver
of England consists of 111 parts of silver and 9 of
copper; or in 1,000 parts, 925 of silver, and 75 of
copper, as already noticed. In order to prevent
fraud, all vessels of silver are required to be stamped
by the Goldsmith’s Company, who are authorized to
search the shops of silversmiths and seize articles

(I) We have also to thank Professor Miller for allowing us to
copy his apparatus, as shown in Figs. 1989 to 1992.

which do not bear ‘the hall-mark of the company.
The company makes a charge of Is. 662?. per ounce ‘on
the weight of the object for the assay thereof and the
impression of the stamp. The larger portion of this
sum is paid over to Government as a tax, a small de-
duction being made for the assay. In France there
are three different standards. The alloy used for the
silver coinage is composed of 9 parts silver and 1 of
copper; for plate, 9%— parts silver to- g— a part of
copper; and for small articles of silver, such as
those used for ornaments, the alloy consists of 8 parts
silver to 2 of copper. The silver coins of the ancients
and many Oriental silver coins are nearly pure: they
contain only traces of copper and of gold.
The addition of a small proportion of copper in-
creases the hardness of silver in a remarkable degree,
without greatly diminishing its whiteness. An alloy
of 7 parts silver and 1 of copper has a decidedly white
colour, although less pure than that of virgin silver.
Even with equal weights of the 2 metals the alloy is
white. The maximum of hardness is obtained when
the copper amounts to -,‘;th of the silver. Articles
formed of alloyed silver are subjected to a process
called whitening, which has the effect of removing the
baser metal from the surface. The article to be
whitened is heated nearly to redness, and plunged,
while still hot, into water acidulated with nitric or
sulphuric acid, by which means the oxide of copper
formed by heating the surface in contact with air is
immediately removed. The matted appearance of the
surface, called blanched or dead silver, due to the
isolation of the particles of silver, is removed by
burnishing, The blanks for coin undergo the pro-
cess of whitening, whence the blanched appearance
of new coin, and the darker appearance of the pro-
jecting portions, occasioned by wear in consequence
of the alloy appearing beneath the pure surface.
Articles of plate are also deadened or matted by boil-
ing them in bisulphate of potash, which acts in the
same way as sulphuric acid.
Silver solder consists of 667 parts _of silver, 233 of
copper, and 100 of zinc. Silver is largely used for
plating the surfaces of articles made of inferior
metals, for which purpose some of the methods
described under PLA'rrne and ELEGTRO-METALLURGY
may be adopted, or the silver may be applied to the
surface of the object in the form of an amalgam, the
mercury being driven off by heat. By a process of
this kind buttons are gilt. [See Burrow] For silver-
ing brass, a mixture of chloride of silver, chalk and.
pearlash is used : the metal is made chemically clean,
and the mixture moistened with water is rubbed on
the sufface.
SIMPLE BODIES. A list of elementary bodies
with their atomic weights and symbols is given under
Arorrrc rnnonr. ,
SINGEING. See BLEACHING, Fig. 138.
SLPHON (m'qbcav, a tube), a bent tube, one leg or
branch of which is longer than the other, used in
raising fluids or emptying casks, &c. In Fig. 1993,
the siphon AB 0 is represented with its shorter leg
AB, immersed in the liquid which is to be transferred
6341
SIPHON—SKEW-BRIDGE.
from the cash A to the measure B. When the shorter
leg is immersed in A the air is removed from the
tube by applying the lips to the extremity o of the
longer limb, and sucking out the air, in which case
the atmospheric pressure exerted on the surface of
the liquid in A, forces the liquid up ‘the short branch
11 B, towards the highest point B; and if this point ‘he
not at a greater height-than about 32 feet, if water be
contained in A, and not more than 30 inches if it be


{I ll l_l p-J'Wr-Z-Etlan;
, r’
l
mercury, the fluid will pass beyond the highest point
B, and-fill the whole of ‘the tube to o. The vessel E
may'then be placed under the open end 0-, and the
whole of the liquid in A situated above the end A ~
will be transferred into E: The use of the siphon is“
more convenient by attaching a stop-cock c to. the end
of the longer branch, and placing’ on the same branch
a small bent tube a‘ t, communicating with the tube
above the stops-cock. When the end of the shorter,
limb is placed in the liquid'to ‘be drawn off, the stop-
cook a“ is closed, and the mouth being applied att the
air-‘is readily sucked out. In some cases the siphon
may be held with its ends upwards, filled with liquid,
the ends closed, turned downwards, and the shorter
immersed in the “liquid to be drawn 0E’.
’ The reason why one limb of the siphon is longer
than the other is' that the atmospheric pressure acts
as forcibly at one extremity of the siphon as at the
other. If when the liquid is raised to the, highest
point B, the mouth be withdrawn from o, the liquid
will fall back into the vessel A. Such also will be
the‘ case if the liquid get no further than n, (which
is the level of the liquid in A,-) because at that
point the upward ‘pressure of the atmosphere prevails
over the downward pressure of the liquid; but
beyond that point in the direction 1* c the downward
pressure of the liquid prevails over the upward
pressure of the atmosphere, and the liquid will flow
out. Thus the motion of the fluid is, as Mr. Webster
remarks, ‘similar to the motion of a chain hanging
over a pulley. If the 2 parts of the chain be equal,
the fluid remains at rest; and it one end be longer .
‘upon a sound principle, the leading feature of
than the other it moves in- the direction of the longer
end. Fresh links, so to speak, are added continuously
to the‘ fluid chain by the atmospheric pressure on the

surface of the fluid, so that the chain being continuous,
the motion is continuous also, and does not cease
until one portion of the chain becomes equal to or
less than the other.
SIZE is made of thin glue [see GnLArINn], and
for finer work,.it is prepared by boiling white leather
or parchment cuttings in water for a few hours, or
until a thin jelly=like substance is formed.
SKEW‘BRIDGE. Square arches, or those which
stand at’ right angles to their abutments, and exert
their thrust in that direction, are described under
BRLD'GE. Any other form of arch being more diflicult
of construction was'of rare occurrence until the in-
troduction of railways»; the usual plan .in carrying a
roadover a stream, being to construct the bridge at
right angles, and to divert the course of the road so
as to accommodate it, as shown in Fig. 19%, in which
the road, the direction of which is indicated by the
dotted line M, 'is carried over the stream s s in the
direction of the curved line, in order that the arch
‘of the bridge may be at right angles to its abut-
ments. In a railway, however, the introduction of
these curves would be highly objectionable, [see
RAILWAYJ and the necessity for carrying the line in
a straight direction over common roads, canals, &c.
I‘ ‘I
\



I
‘,1 L. \
.-=¥-"r|,’/.;,_‘L L. "'
l.



r I -II
\W
k.‘ l
y‘, —''‘i P4415
%§;¢:'¢;"_i;_-ATIL -
//.//=’/‘ . ‘é '
4/421?’ I‘“ ,._,.
‘:1 ..
“I, J
led to the application of the skew-bridge, or oblique
arch, in those cases where the line of railway inter-
sected the road or canal, &c., obliquely, as in Fig.
1994, where s is the stream, and r r the double line
of railway. The introduction of the skew-arch on
the Liverpool and Manchester Railway, by George
Stephenson, was regarded as a complete novelty; but
the writer of the article SKEW-BRIDGE, in the Penny
Cyclopedia, refers to the article OBLIQUE Ancnns, in
Eees’s (Zr/010104251554, which is said to have been written
by an engineer named Chapman, who mentions
. oblique arches as being in use prior to 1787, when he
introduced a great improvement in their construction.
Down to that period such arches had been constructed
in the same way as common square arches ; the
voussoirs being laid in courses parallel to the abut-
ments.- In such a case, it is evident that only a por‘
tion of the arch would be supported by the abut-_
ments, the other portions being sustained by the
mortar only. In constructing a bridge over the
Kildare canal, Mr. Chapman wished to avoid the
diverting of certain roads, and he was led to the
invention of a method of constructing oblique arches
which, according to him, was, that the joints of the
voussoirs, whether of brick or stone, should be
SKE W-BRID GE.
635
rectangular with the face of the arch instead of being
parallel with the abutments. The courses would
thus be laid in the manner indicated by the dotted
lines, Fig. 1995. A
bridge on this plan near
Naas, called the Finlay
bridge, crossed the ca—
nal at an angle of only
39°, the -oblique span
being 95 feet, and the
height of the arch 5 feet
6 inches. Mr. Chap-
man remarks that the
Fig. 1995. lines on which the beds
of the voussoirs lie are obviously spiral lines, to
which circumstance much of the singular appearance
of oblique arches may be attributed.
Skew-bridges are now very common, and many
others are of considerable obliquity. At Boxmoor,
on the North Western Railway, is a brick arch, of
which the angle is 32°, the square span 21 feet, and
the oblique span 39 feet.
Various methods have been proposed for forming
the voussoirs with accuracy, and disposing them with
advantage. In the year 1838, Mr. Nicholson read
before the British Association, for the advancement
of science, a paper on the principles of the oblique
arch for the guidance of Engineers. The following is
an abstract of this paper. According to Mr. Nichol-
son, the principles of the oblique arch require,
“that 5 of the faces of each stone be prepared in
such a manner that 4: of them shall recede from the
fifth; and when the stones are arranged in courses,
the surfaces of the fifth face shall form one con-
tinued cylindric surface, which is the intrados, and
the other 4: surfaces shall form the beds and ends of
the stones on which they join each other. In every
course, two of the opposite surfaces of the first stone,
two of the opposite surfaces of the second stone, and
so on, shall form two continued surfaces throughout
the whole length of each course; and the edge of
each of these continued surfaces in the intrados shall
be a spiral line. If a straight line be drawn through
any joint in one of the spiral lines, perpendicular to
the axis of the cylinder, the straight line shall coin-
cide with that continued surface which is a bed of
that course, and the straight line thus drawn ‘shall be
perpendicular to a plane which is a tangent to the
curved surface of the cylinder at that point in the
spiral line; therefore the straight line thus drawn
shall be perpendicular to another straight line which
is a tangent to the spiral at that point. When the
intrados is developed, the spiral lines which form
the edges of the courses shall be parallel, and their
distances shall be equal; and the spiral lines which
are the edges of the ends of the stones shall be
developed in straight lines, perpendicular to those
lines which are the developments of the spirals
of the edges of the courses. It is evident that
each of these spiral lines will have a certain radius
Of curvature, and that this radius of curvature,
at any point of the spiral line, will be equal to the


radius of curvature at any other point in the same
spiral; and that the radius of curvature at any
two given points in two spiral lines, which have
parallel developments, are equal to one another.
Therefore, if two points be taken in a spiral line, and
if a straight line be drawn from one of them parallel
to the axis, and if through the other, the cylinder be
cut by a plane perpendicular to the axis, and if the
surface of the cylinder be developed, the development
will be a right-angled triangle, of which the quotient
arising by dividing the product of the square of the
hypothenuse and the radius of the cylinder by the
square of the development of the circular are inter-
rcepted between the spiral and the straight line, will
- be the radius of curvature of that spiral. By these
principles the geometrical construction of an oblique
arch may be easily made for the use of the workmen,
or calculations of all the parts may be expeditiously
and accurately performed by the engineer; it is only
necessary to have given the angle of obliquity of the
acute-angled pier, the width of the arch within its
abutments, the height of the intrados above the level
of the springing, the perpendicular distance between
the planes of the two faces, and the number of arch
stones in each elevation, in order to construct the
arch.”
The writer of the article SKEW-BRIDGE, in the
Encyclopedia Britannica, opposes this theory, and
states his opinion that the most perfect method of
constructing a skewsarch, is to cut the stones so that
two of the opposite sides of each stone, or at least
the middle part of these sides, may be as nearly as
possible at right angles, both to the soiiit, and also
to the direction of the passage over the bridge.
Mr. Buck, in his Treatise on Skew Bridges, states
that the erection of these structures increases in
difiiculty with the obliquity of the angle from 90° to
415°, which is supposed to be the most hazardous
angle for a semicircular arch; but that, beyond that
point, the dilhculty does not increase, but rather
diminishes to about 25°, which appears to be about
the limit for a semi—cylindrical arch. Mr. Buck
states, that oblique elliptical arches are deficient in
stability, more diflicult to execute, and more costly
than semicircular or segmental arches.
Curved iron ribs, or girders, are applicable to the
oblique as well as to the square arch, since each rib
can always be placed in a plane which is both vertical
and runs in the direction of the upper passage. The
girders are laid parallel, but the end of each girder is
in advance of the one preceding it, as in the ground


Fig. 1996.
plan, Fig. 1996, the dotted lines showing the situation
of the ribs which support the platform. Our railways
exhibit some fine examples of these structures.
SKIN. See GELATINE—LEATHER.

636
SKIVE.-;-—SLATE--SLATING.
3 SKIVE, a name sometimes applied to the iron lap
used by the diamond polishers in finishing the facets
of diamonds. It is charged with fragments of diamond
powder which are burnished ‘into its surface. The
Dutch diamond cutters call it a scizg/f See Cannon
'—-LA.PIDARY Wonx.
SLAG. See IRON. ‘ ,
SLATE. Under this word are included a variety
of substances, of which the following is abrief account.
Mica—slate, a mountain-rock of vast extent, composed
of quartz and mica. ,Its structure is foliated, depend-
ing on the large proportion of mica. It is thin and
slaty, and breaks with a glistening or shining surface.
Its usual colour is grey orpsilvery grey. The more
compact varieties are used for door and hearth stones,
for flagging, and for lining furnaces. Dana states
that the finer arenaceous varieties make good scythe-
stones. Homblendeelate resembles mica-slate, but is
less glistening, and does not break into such thin
slabs. Its toughness makes it a useful flagging.
TaZeose—slate contains talc intcad of mica, and hence
it has a more greasy feel that mica—slate. It is used
for scythe-stones and bones. [See HONE or Horm-
SLATES.] Cltlorz'a‘e-slate is of a dark-green colour,
similar to talcose-slate. 4rgz'llaceoas-slzole, or clay-
slae‘e, has the same constitution as mica-slate; but
the particles are so fine as not to be distinguished.
Shale is usually distinguished from clay—slate in
having a less perfect structure, and being more brittle.
The schists include the coarser varieties. [See
SCHIS'L] Clay-slate is abundant in Great Britain.
It is found in the Highlands of Scotland from Loch-
lomond by Callender, Comrie, and Dunkeld, resting
on, and gradually passing into, mica-slate. Roofing-
slate occurs in Cornwall and Devon, in various parts
of North Wales and Anglesea; in the north-east of
Yorkshire, near Ingleton, and in Swaledale ; also in
Cumberland and Westmoreland. It also occurs in
Wicklow, and other mountainous parts of Ireland.
The slates exhibited in the Great Exhibition are no-
ticed in the In'rnonucronr EssAY, page lxxxi.
The best beds of roofing slate improve in quality as
they lie deeper beneath the surface. The blocks are
got out by blasting. They are split into sheets, some-
times exceedingS feet by 4:, by means of long, wide,
and thin_ chisels, applied on the edge, parallel with
the laminae, and struck with a mallet or hammer;
cross grooves are then cut on the flat face so as to
divide ‘the slabs into the required lengths, which are‘
separated by a blow with the chisel. Each piece is
next split into thinner leaves by applyingfine chisels
to the edges. Each leaf is then roughly dressed on
a. block of wood with a chopping-knife, as will be ex-
plained more particularly in the next article. By long
exposure to the air after having been quarried, the
blocks may lose their property of being divided into
thin laminae. In such a case the ‘blocks are said to
have “lost their waters.” Hence, in a slate quarry,
, the number of splitters ought to be proportioned to
v
the number _ of block-hewers. The blocks are ren-
dered more fissile by frost, but a subsequent thaw
makes them refractory; another frost partly re-

stores the property of- splitting. After a succession
of frosts and thaws the quarried blocks can no, longer
be split up into leaves. The desirable properties of
roofing slate will be noticed under the next article.
Slate is now used for chimney-pieces, internal de-
coration, and furniture. For which purpose the large
sheets procured by splitting the blocks, are sawn into
rectangular pieces and slabs by means of circular
saws with rather a slow motion. The process of saw—
ing is rather one of crushing than cutting, and the
slate is carried up to the saw by means of machinery,
so that it cannot recede from the saw-teeth. The saw
requires to be sharpened about 41 times a-day. These
slabs are then planed for billiard—tables, &c. in ma-
chines which resemble the planing machines used for
metals. The planing tools are about 6 inches wide:
the jambs for chimney-pieces and other mouldings,-
not exceeding this width, are planed with figured tools
of the full width. Slate is ornamented after the man-
ner of papier maché and china: imitations of marbles
and granites being supplied at one-third the prices of
marble, for which purpose the slate is rubbed smooth,
then j apanned to resemble black marble, or of various
colours and devices, like tea-trays : the japan is.
hardened by baking the articles; they are then
smoothed with pumice-stone and polished with rotten-
stone, as described under JAPANNING. Mr. Henning
made use of slate as the material for his moulds or.
intaglio engravings of the has-reliefs of the frieze of
the Parthenon and other antique marbles. Pumice-
stone gives a- grain to slate ‘suitable for writing on :-
the greyness produced by the pumice may be removed
by a slight rub of oil, or a wash of common writing-r
ink allowed to dry on, Slate makes a good drawing-
board. . .
Dana states that slate rocks are used for grave-
stones. “_We .cannot go through New England,
cemeteries without frequent regret that a material,.
which is sure to fall to pieces in a few years, should
have been selected for such records.”
W/zet slate or Turkey bone is noticed under HoNn.
Drawing-slate or black-elm”; is used in crayon drawing-
The best kinds are from Spain, Italy, and France. It
is also found in Caernarvonshire'and the island of
Islay. _ Its colour is greyish black ; it is very soft,
sectile, easily broken, and adheres slightly to the.
tongue; its density is 2'11. Adhesive-slate is of a
light greenish—grey colour ,- it is readily broken; its
streak is shining, and it adheres strongly to the
tongue; it absorbs"waterlrapidly, with. a crackling
sound and the emission of air-bubbles. Bituminous
slzale is a slate clay impregnated with. bitumen. [See
SHALE—ASPHALTUM.] Slate clay is one of the alter-
nating'beds of the coal measures. [See Conn] It is
an infusible compound of alumina and silica, and is
used for making fire-bricks. Stonrbridge clay is. a
variety of this schist. [See Inon, sec. vii—Format:
and PORCELAIN, sec. iii] . . _
SLATING is. the art of covering the roofs of
buildings with‘ slates. ~ ‘The slates used in and" about.
the metropolis are for the most ‘part from Bangor in_
Caernarvonshire; they are of a light'sky: blue colour ;__
SLATING.
637
“slates from Westmoreland are of a dull greenish hue.
Scotch slates are not much esteemed. Westmorelmzrl
slates are from 3 feet 6 inches to 1 foot in length, and
from 2 feet 6 inches to 1 foot in breadth. Welslz rags are
next in repute, and are nearly of thelsa'me- dimensions
as the Westmoreland slates. Impem'als are from 2 feet
6 inches to 1 foot in length, and about 2 feet wide.
Duefiesses are about 2' feet long and 1 foot wide.
Cowztesses run about 1 foot 8 inches in length by
about 10 inches in width. Leelz'es are usually about
15 inches long and about 8 in width. They are sold
by the thousand of 1200. There are also Demzgbole
slates and Taoistoel: slates; of the latter those called
doubles run about 13 inches in length by 6 inches in
width.
Slate should be of a fine sound texture, since if
absorptive of moisture it will cause the boarding
beneath it soon to become rotten. Good slate is very
durable, and its value may be estimated by striking
it, when, if good, it will yield a clear bell—like sound.
The light blue slates are said to retain moisture much
less than the deep black—blue variety. Good slate is
hard and rough to the touch, while an absorbent
variety has a smooth greasy feel. The value of
slates may be tested by setting them up edgewise in
water which reaches about halfway up the slate: if
in the course of 6 or 8 hours they draw water and
become wet at the top, they are spongy and absorbent:
the smaller the height to which the water rises the
better the slates. A more accurate test is to weight
pieces of slate at a certain temperature; to allow
them to remain in water foi“'12 hours; then to take
them out and wipe them dry. On weighing them
again their comparative values will be indicated by
the increase of weight, those which have absorbed
least water being most valuable.
The slates as supplied from the quarry are squared
and sorted by the slater, the largest being selected
for the eaves. Each slate is examined, the strongest
and squarest end selected, and the slater holding it a
little slanting upon and projectingiabout an inch over
the edge of a small block of wood cuts'away one of
the uneven edges of the slate with an iron knife or
chopper, called a satire, saw, or zare, about 16 inches
long and 2 in width, somewhat bent at one end, with
' a beech handle at the other; on its back is a projecting
piece of iron about 3 inches long drawn to a sharp
point. He next with a slip of wood gages ‘the other
edge parallel to the first that was trimmed, and having
shaped this also, squares the ends, and lastly, with the
sharp point onthe back of the zax, peeks two small holes
through the slate for the passage of the nails used for
fastening the slate to the roof. The upper surface of
a slate is called its back, the under surface its bed,
the lower edge the tail, and the upper edge the lzeacl.
The nail-holes should be made as near to the head as
may be without breaking the slate, and at a. uniform
distance from the tail. Except in the most inferior
work every slate should be fastened by 2 nails. The
nails used are of copper, zinc, or tinned iron.
The house-carpenter prepares a base or floor for the
slates. For eloaeles and ladies boarding is required to

ensure water-tight covering. The boards should be
laid even, and be well secured to the rafters with
close joints. The larger kinds of slates will lie firmly
on Mtterzs or narrow portions of deal about. 25,- to 3
inches wide, and % inch thick for countesses, but
thicker for heavier slates. The slates should all be
of the same width, and the edges true. The battens
are nailed to the rafters at the gage to which the
slates will work. That portion of each course of
slates which is exposed to view is called the margin
of the course: the width of the margin is the gage.
The bond or lag is the distance which the lower edge
of one course overlaps the slates of the next course
below it, measuring from the nail-hole. The bond
should not be less than 2 inches, and need not be more
than 3% inches: the half of what remains is called
the gage. Thus for a slate 2 feet 3 inches in length,
if the bond be 3'inches, the gage will be 1 foot.
The slater‘ first nails down all round the extreme
edges of the roof slips of wood about 2% inches wide,
a inch thick on one edge, and chamfered to an arris
on the other: these are termed tilting fillets. He
then begins to'lay the slates, beginning at the eaves,
where he uses the largest slates, setting their lower
edges to a line, and securing them by nailing them
down to the boarding. See Fig. 1997. In some
cases the eaves’ course is made double by placing
a second row of
slates under the first
so as to cross and
cover all its joints;
such slates are
pushed up tightly
under those which
are above them, and i
are seldom nailed, their own weight and the weight of
those above them retaining thein firm. When the
caves are finished the slater strains a line on the
face of its upper slates parallel to its outer edge, and
as far from it as he thinks sufiicient for the lap of
those slates which are to form the next course, which
is laid and nailed even with the line, and crossing the
joints of the upper slates of the eaves, as shown in
the figure. This lining and laying of the slates is
continued until the slatergets close up to the ridge
of the roof, which is covered by an overlap of sheet
lead. In nailing a slate it must not be strained or
bent, or it will split on some sudden change in tem-
perature. Slating should bev pointed or toreizeel on
the inside with lime and hair in order to exclude the
wind and to prevent snow from driving in. _
Patent slatz'flg, as it is called, is formed by laying
wide slates side by side and covering their joints with
narrow slips bedded in putty, the overlap at the ends
not being greater than the bond in the usual method.
Neither boards nor fillets are used, but the slate is
screwed to the rafter, its width being suificient to ex-
tend from rafter to rafter; and the covering slips are
also screwed as well as bedded in putty. Slating of
this kind may be laid at so small an elevation as 10°:
in ordinary slat-ing the angle should not be less than
25°. The objections to patent slating are that it is


Fig. 1997.
638
SOAP.
liable to become deranged by a very slight settlement
of the building, and the putty is apt to become dis-
lodged and let in the rain.
Slaters’ work is measured by the square of 100
superficial feet, with an allowance for cutting the slates
at the hips, eaves, round chimneys, &c. Slabs for cis—
terns, baths, shelves, &c., are; charged by the square
foot, according to the thickness of the slab and the
work bestowed. Rubbed edges, grooves, &c., are
charged per lineal foot.
SLIDE-REST. See Iurnonucronr EssAr, p. clx.
SLIP. See SHIP.
SLITTIN G MILL. See LArIDAuY woltx, Fig.
127 3.
SLOTTING ENGINE. See SHArINe-MAcuINE.
SLUIGE. See DRAINAGE-:SEWER.
SMALT. See COBALT.
SMELTING. See IRON—METAL.
SMOKE. See CHIMNEY—WARMING and VENTI-
LATIoN.
SMOKE JACK. See WARMING and VENTILATION.
SNUFF. See TOBACCO.
SOAJ? is a compound of certain fatty substances
with soda or potash. Its detergent properties depend
entirely upon its alkalies, a portion of which combines
with the greasy matters intended to be removed by
washing,»rendering them soluble or miscible with water
without corroding. The caustic alkali alone would
act more powerfully as a detergent, but it would cor-
rode organic substances if used freely, and destroy
some of the ‘colours of dyed goods. In ancient times
the alkali was so used, in a more or less caustic state,
and is still employed by cottagers in the lye obtained
by filtering water through wood ashes. The Hebrew
word don't/z, which, in J er. ii. 22, has been rendered
cope, refers to vegetable lye, or potashes. In another
passage (Mal. iii. 2) the fzdler’s 80])6 is from the He-
brew word net/ter, which is mineral lye or soda. The
first mention of soap, properly so called, is said to be
by Pliny, who declares it to be an invention of the
Gauls, although he prefers the German to the Gallic
soap: he states that soap was made of tallow and
wood ashes; that the best was made of goats’
tallow and beech-wood ashes, and that there were two
kinds of soap, laced and soft} Soap is also mentioned
by Geber, in the second century, and at a later period
is frequently referred to by the Arab writers as being
used not only for detergent purposes, but also as an
external remedial application. It would be difiicult
to trace the history of soap to modern times: there
is, however, evidence of the manufacture having been
conducted in the reign of Queen Anne almost precisely
as at present, a clear proof of the injurious influence
of the excise on the manufacture. In France, and
other countries, the art of making toilet soaps, as well
as common varietiesyhas been constantly improving,
and the export trade of France is large. We are,
however, thankful that the soap-tax in Great Britain
is at length repealed, and we may hope to see the
manufacture speedily recover from its stationary con-

(1) An historical notice of soap will be found in Beckmann’s
History of Inventions.

dition, and occupying a higher position among the
chemical arts, enrich science with new facts, and
open up new branches of industry. Indeed there is
scarcely any subject that is more likely to reward in-
vention than a well-directed inquiry into the various
combinations of the fats and oils with alkalies. The
innumerable metamorphoses which the fats and oils are
capable of undergoing; the small number of elements
concerned in their composition; the large number of
cheap substances in which those elements exist (as
in coal, wood, bituminous shale, &c.), lead to the hope
that the chemist may one day be able to obtain from
them marketable substances resembling tallow, wax,
and spermaceti.
The manufacture of soap has been greatly assisted
and promoted by Ghevreul’s researches on the nature
of fats, [see QANpLn—Orns and FATS], which have
satisfactorily explained the nature of saponification;
and by Leblanc’s method of procuring soda from com-
mon salt, [see SonIInm] which gradually liberated the
manufacture from its dependence on barilla and kelp
as sources of the alkali. It is stated in the Jury
Report, Glass xxix., that Mr. James Muspratt, who
was the first to carry out Leblanc’s process on a large
scale in England, “ was compelled to give away soda
by tons to the soap-boilers before he succeeded in
convincing them of the extraordinary advantages to
be derived from the adoption of this material. As
soon, however, as he had effected this, and when the
soap-boilers discovered how much time and money
they saved by using artificial soda, orders came in so
rapidly that Mr. Muspratt, to satisfy the demand,
had his soda discharged red-hot into iron carts, and
thus conveyed to the soap-manufactories. From that
period a constant race was kept up between soap-
making and the artificial production of soda; every
improvement in Leblanc’s process was followed by an
extension of the soap-trade, and it is a curious fact,
that the single sea-port of Liverpool exports annually
more soap at present than did all the ports of Great
Britain previous to the conversion of chloride of
sodium into carbonate of soda. The manufacture of
soap has, on the other hand, been a powerful stimulus
to the preparation of soda, and of the important
secondary product, hypochlorite of lime (bleaching
powder), which are so intimately allied with almost
all branches of chemical trades; thus soap occupies
one of the most important pages in the history of
applied chemistry. The increase in the consumption
of this article has led, moreover, to the discovery of
new materials for its production; it has opened new
chamiels to commerce, and thus it has become the
means as well as the mark of civilization. Almost
simultaneously with the employment of soda, the oils
of the cocoa-nut and the palm have been introduced
into the manufacture of soap.” , The increasing con-
sumption of these oils will be seen from the following
statement of imports into the United Kingdom :—
Palm-oil. Cocoa-nut oil.
1820 17,456 cwts. ....... .. 8,353 cwts.
1830 213,476 — ....... .. 8,534 —-
1840 .......... .. 315,503 -— ...... 42,428 ~—
1850 447,796 —- ....... .. 98,039 -
SOAP.
639*
Tallow is also largely employed in this country in
the manufacture of soap, and in France olive-oil is
the chief material.l Lard, linseed-oil, rapeseed-oil,
fish-oil, kitchen—stuff, bone, fat, and common rosin,
are also in great demand by the soap-maker,
Referring tothe articles CANDLE and OILs AND FATS
for the chemical constitution of fats, it is only neces-
sary to state in this place enough on the subject to
render the details of soap-making intelligible. Fats
consist of two proximate, fatty substances—oleine,
which is fluid at common temperatures, and stea-
Mae, which is solid. A fat is solid, soft, or fluid,
at ordinary temperatures, according to the pro-
portions of these two bodies. Stearine may also
contain an analogous body, maryarz'ae, in various
proportions: the solid fat or tallow of the sheep
contains chiefly stearine; lard and olive oil con-
tain chiefly margarine ; while the solid fat of palm-
oil is denominated palmz'zfz'ae, and that of cocoa-nut
oil cocz'ae. Stearine, margarine, oleine, palmitine,
and cocine, are in their turns compounds of certain
fatty acids with oxide of’ glyceryl or glpcerz'ae. Thus
the acid of oleine is olez'c acid, which, in combination
with the oxide of glyceryl of the oleine forms oleate
of glg/cerz'ae. Stearine contains stearz'c acid, which
forms with the oxide of glyceryl of the stearine,
sz‘earate of glycerz'aze. So also margaric acid forms
margarate of glycerine, and so on. Now these fatty
compounds, stearine, oleine, 860., are decomposed by
the free alkalies, potash, or soda, their acids quitting
the glycerine to unite with the alkalies, thus form-
ing a soluble soap, the glycerine remaining behind in
the mother liquor. The hard soaps of commerce, when
made with oils (palm and cocoa-nut oils excepted),
are chiefly mixtures of oleate and margarate of soda,
with little if any stearate. When the hard soaps are
made with animal fats they are mixtures of oleate,
stearate, and margarate of soda. Stearine, oleine, &c.,
are also decempesed by the earths, lime, and mag-
nesia, and by metallic pxides, such as those of lead
and zinc. Lead soap is an insoluble oleate of oxide
of lead: it forms the cZiaafig/loa plaster of pharmacy.
Zz'ao soap is an ointment. Zime soap is insoluble; it
is formed in the shape of a crudfprecipitate when
soluble soap is mixed with hard water; the carbonate
or sulphate of lime in the water and the soap mutu—
ally decompose each other; the fatty acids of the
soap combine with the lime in the water, and the
carbonic or sulphuric acid of the lime unites with the
alkali of the soap. No lather can be formed until
the whole of the lime is thus taken up.
As in the time of Pliny, sgaps are still divided into
hard and sqfl. The hard are made from fats and
vegetable oils, with soda as a base; the soft, from
fish oil or vegetable drying oil, with potash as a base.
A hard soap may be made with potash if a solid fat

(1) Now that the duty is taken ofi‘ soap, the manufacturer may
find it to his interest to adopt some of the French processes. They
are well described in one of the Manuels-Roret, entitled, “ Nou-
veau Manuel Théorique et Pratique du Savonnier, ou 1’A1't de
faire toutes sortes de Savons; par Madame Gacon-Dufonr, et MM.
Julia de Fontenelle, Thillaye et Malepeyre.” Paris, 1852.

be employed; but soda soaps are always harder than
potash soapsx with the same fatty substance. The
stearate of soda, which may be taken as the type of
hard soaps, scarcely changes with ten times its weight
of water; but the stearate of potash forms therewith
a thick paste or viscid solution.
In this country and in the north of Europe white
soap is made from tallow and soda. In France, Italy,
and other places where the olive—tree grows, an in-
ferior olive oil is used for the purpose. One ton of
soap requires from 10 to 1A cwt. of tallow or olive
oil; the proportion of alkali varies in different works;
but supposing it to be pure and dry, the proportion
required for the saponification of different oils and
fats varies from about 10 or 141 soda, and from 15 to
20 potash, for every 100 parts oil or fat. In the best
Windsor soap the tallow is mixed with about 10 per
cent. of inferior glive oil, and in white soap a portion
of lard is sometimes substituted for; an equal portion
of tallow; this prevents the soap from being too
hard.
When a soluble sgiap is made by boiling a solution
of soda or potash with stearine, the stearate of soda,
or soap, remains snspended in the water of the solu-
tion, together with ~the glycerine, frgm which it is
separated by means of a solution of dommon salt, in
which soap is not soluble, while the excess of alkali,
the water, and the glycerine combining with the salt
water, the soap separates, floats on the surface, and
can be thus removed. Soaps being also insoluble in
strong alkaline lyes, the separation is sometimes
effected by boiling down the soap to a certain con-
sistence, when it separates from the excess of lye.
The soap made with cocoa-nut oil is, however, soluble
in very strong brine, so that it cannot be separated
by this means unless the oil be largely mixed with
other fats. This property of dissolving in salt water
renders cocoa-nut oil well adapted to the formation
of a marine soap. Cocoa-nut oil soap solidifies with a
much larger quantity of Water than most other soaps.
A maker has been known to vend a cocoa—nut oil soap
containing '7 5 per cent. of water, 25 to 35 per cent.
being a large quantity for any but potash soaps,
and these seldom contain more than 50 per cent.
The French makers allow 30 per cent of water for
mottled soaps, and 45 to 46 per cent. for white
soaps; but cases have been known in which soaps
combined with from 83 to 154'. per cent. of water
have been sold. Floating soaps contain a large pro-
portion of water.
Most of the potash or soda soaps are readily soluble
in alcohol: on evaporating the solution, the soap
remains in a transparent state, forming traaspareat
soap.
When an insoluble soap is formed, as by boiling
oleine with oxide of lead in making diachylon, the
oleic acid of the oleine combines with the metallic
base forming the insoluble soap, while the glycerine
of the oleine separates in combination with the water.
Common rosin, consisting chiefly of pinic acid,
with a little sylvic and colophonic acids, unites with
alkalies under certain conditions. Thus when rosin is
6410
SOAP.
boiled with soda, it forms chiefly pirzale of socla, which
gives the distinctive character to yellow soap.
The alkali used in making soap should‘be caustic.
Although the carbonates of the alkalies by long
boiling will saponify the fats, the operation is tedious,
and the saponification incomplete. The crude alkali
sent to the soap-works is usually a carbonate; it is
mixed with recently slaked lime and a certain bulk of
sand, for facilitating the process of filtration. The
mixture is placed layer by layer in a large tank, the
layers being separated by rush matting. The tank

Fig. 1998.
ALKALI TANKS.
is filled up with water, and allowed to stand for
from 12 to 18 hours : a plug is then removed from
near the bottom of the tank, the lye is drawn oil’,
and the tank again filled up with water. This opera-
tion is repeated 5 or 6 times; the leys are kept in
separate reservoirs, and are called, first ramzz'ag, second
raarzz'rzg, &c. In this operation the lime takes car-
bonic acid from the alkali, leaving the latter in a
caustic state.
Soap is usually manufactured by one of two pro-
cesses. The first is the colcl process, in which the
materials are combined at a temperature below the boil-
ing point of water. This process is also called the small
boiler process, on account of the comparatively small
size of the vessels in which it is conducted. The
alkali used in this process is prepared from the purest
commercial soda, and is concentrated by evaporation.
The chloride of sodium and sulphate of soda, with
which the soda is contaminated, not being soluble in
a strong solution of soda, they crystallize out when
the lye is left for some days. The proper proportion
of fat is melted, and the lye of known density is
measured out, heated and stirred into the melted fat.
Saponification now takes place, and the soap solidifies
on cooling. By this process the glycerine is con—
tained in the soap, and either the fat or the alkali is
in excess on account of the difficulty of exactly pro-
portioning the two.
The other method, which is the common one, is
termed the large boiler process, the boilers, or coppers
as they are called, being of large size, each capable of
distinct pieces, which are united by a cement com-
posed of iron rust, sal ammoniac, and sulphur; the
top and middle pieces called curbs are set in masonr ,
and heat is applied either by means of steam or by a
small open fire, acting on the lower part of the copper.
All the oil or tallow is introduced at one batch into
the copper, but the alkali is added in several distinct
portions. The weakest solution of caustic lye is
pumped up into the copper, (see Fig. 1998.) Heat
is applied until the lye ceases to be caustic. Salt may
be added with the lye or in the present stage. It is
better to add a certain portion with the lye, since the
lye and the tallow form a uniform emulsion, which is
liable to burn to the bottom of the boiler, were it not
for the solution of salt, which forms a protective
layer beneath the saponifying mixture. On allowing
the contents of the copper to cool,‘the spent lye and
the salt settle at the bottomiof the copper, whence
they are pumped up, the excise regulations not allow-
ing them to be drawn ofi” from below. This spent
lye, containing glycerine, sulphate of soda, and chloride
of sodium, is thrown away to waste. This first boil-
ing forms what is called an operatioa, and 3 or 41
operations with leys‘ of gradually increasing strength
are required to lelll l/ze grease, or to cause saponifica-
tion. It is known when the tallow is saponified, when
a little of the compound is squeezed between the
finger and thumb, and allowed to cool. If the process
is completejit will separate from the finger as a hard
cake; it will have lost the peculiar taste of grease, and
have acquired a slightly alkaline taste. If, on the
contrar , any tallow remain unsaponified, it oozes
out by pressure, and is evident both to the sight and
taste. The more certain test of the saponification
being complete is, to decompose a portion of the soap
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Fig. 1999. BOILING.
by means of an acid, and if the resulting \grease is
not entirely soluble in boiling spirits of wine, the
saponification‘is imperfect. In making common yel-

holding many tons. It is made of cast-iron in 3
low soap the resin is usually added at this stage, the
soar. *
641
quantity being id or ith the weight of tallow em.
ployed.
But even when the saponification is complete the
soap is not in a fit state for the market. It consists
of innumerable globules, all separate and distinct from
each other: these must be made to coalesce into a
homogeneous mass, for_which purpose the soap is
fitted,- z'. e. the contents of the copper are fused in
a weak ley or in water, and the boiling kept up for
some time, the mass being prevented from boiling
out of the copper by dashing shovels into it so as to
break the froth and favour the evaporation. During
this process, in making white or carol soap, the black
impurities of the materials (called m'gre) fall to the
bottom; but in making mottled soap, the mixture is
left in a thick or viscid state, so that the nigre cannot
subside. When the process is finished, the fire is ex-
tinguished, and the lid is shut down. After the lapse
of one, two, or three days. according to the kind of
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Fig. 2000.—-FI.LLING THE FRAMES.
soap, the semi-fluid mass is ladled out from the preci-
pitated ley into‘ rectangular frames, or sesses, as they
are called in Liverpool, of certain dimensions pre-
scribed by the Excise, viz. 45 inches long by 15 inches
wide, interior dimensions: they are each ‘about 10
inches deep, and are made smooth, so as to fit closely
together: they are piled up one upon another, and
bound tightly together by means of iron screw-rods,
to the height of from 5 to 12 feet, forming a sort of
rectangular well, capable of holding about 2 tons of
soap. Within this well the soap cools and solidifies.
For yellow soap the frames are of cast-iron. Both
kinds of frames are shown in Fig. 2000.
When the soap is solid and cold, the screw—rods are
removed, the frames lifted off, and the soap stands
as a compact mass, moulded to the interior form of
the frames. It is cut by wires into slabs 2 or 3
inches thick, and these are subdivided into bars for
sale. These bars are piled away crosswise, in the
form of a well, interstices being left for the circula-
tion of air. The soap is allowed to remain in this
condition for some time, that the solution of salt,
with which the soap is slightly impregnated, may
exude.
The nigre which is left in mottled soap consists
VOL. II.

chiefly of sulphuret of iron, produced by the action of
the lye (which always contains a small quantity of
sulphuret of sodium) on the boiler. _At Marseilles
f1 ff it",

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Fig. 2001.—cur'rme THE soar nv'ro BARS.
and other places where olive oil is used in making
soap, a quantity of green copperas (sulphate of iron)
is added, in which case the mottling is produced both
by the black sulphuret of iron and by the oxide of
iron, the red portion, which forms a true from soap.
When the soap is ladled out of the boiler it is of
a uniform slate tint, but as it cools the metallic por-
tions separate into nodules, and by the trickling of
the excess of lye through the mass, they assume those
forms to which the term mottled is applied. Mottled
or marbled soap is also formed by sprinkling a small
quantity of lye, strongly impregnated with sulphuret
of iron, upon the soap immediately after the last boil-
ing: this, filtering slowly through the soap, produces
the required effect.
It will be seen, from the foregoing details, that the
large-boiler-process is a skilful adaptation of chemical
processes, whereby a very pure chemical compound is
obtained from comparatively impure materials.
Patents have been taken out from time to time for
varying the processes, but they do not appear to have
met with much success in this country, probably on
account of the inflexible requirements of the Excise
laws preventing hitherto the experimental inquiry into
new suggestions. Mr. A. Dunn proposed to effect the
saponification in close vessels at the high temperature
of 310° Fahr. Mr. Hawes, on the contrary, pro-
posed to make use of strong lyes, and to mix by
mechanical action in a comparatively cold state. The
product is then boiled and fitted as usual. Both these
plans have been patented. Other patents for sup-
posed improvements, are in reality (as it is remarked
in the excellent Jury Report on Soap) plans for the
adulteration of soap; such, for example, as the prepa-
ration of soap from bones, fish, &c. which is merely
introducing an adulteration of gelatine. A similar
censure applies to plans for the introduction of Cornish
clay, fuller’s earth, 85c. into soap. The sz'lz'eated soap,
properly so called, is an excellent article. It is a
mixture of silicate of soda with hard soap to the
T 'r
642
SOAP.
‘‘ rosin.
extent of one-fifth. In this case the additional quantity
of alkali increases the detergent properties of the
article. It is, however, usually made by mixing with
the pasty soap while in the frames a quantity of
Cornish clay previously rubbed up with caustic lye.
It is stated that such soaps can be used at sea with
salt water : hence theyprobably contain cocoa-nut oil.
Floating soap is prepared by melting ordinary soap
with the addition of a} certain proportion of water,
and then heating it into a thick froth by means of
a, paddle until it occupies thrice its original bulk.
Curd or white~ soapcontains in 100 parts, grease
61,,soda 6'2, and water 328. Curd soap is too hard
and compact ‘for domestic use, but the introduction of
lard for white, and rosin for yellow soap, has the effect
of softening it. Rape-oil, in the proportion of one-fifth,
has a similar effect on olive-oil soap. Asrosin contains
no, glycerine, it is not capable by itself of forming
soap with an alkali. In making yellow soap, palm-
oil is now generally substituted for tallow; about 3%
parts ofpalm-oil being used for every one part of
It’ the rosin be in larger proportion (as it
often is), the soap is soft and dark-coloured. The
rosin‘ is introduced in coarse powder, with the last
charge of lye, when the saponification of the palm-
oil is nearly complete. It is well mixed by agitation,
and the boiling continued for some hours, lye being
occasionally added, to preserve an excess of alkali
until the'soap is fully formed, when the lye is with-
drawn, and weak fresh lyes added, for eliminating
the glycerine. The resinous scum which rises to the
surface is removed for another operation, and the
soap is conveyed to iron frames to solidify.- Yellow
soap usually contains 1 part soda, from 10 to 11 parts
oil and rosin, and from or to 50 per cent. of water;
the latter quantity, however, is far too much. Of late
years the soap-maker has been supplied with line
American rosin, which is much purer and of a paler
colour than the English; hence yellow soap is much
improved, and is now called primrose soap from its
pale yellow colour. Yellow soap is produced in the
largest quantities in England. Mottled soap is next
in importance. Curd soap is used largely by the cloth
manufacturers of Yorkshire, and the lace and stock-
ing bleachers of Nottingham. Soap made from kitchen
stuff, bone fat, &c. is too soft for general use ; but the
introduction of about .gb-th of fused sulphate of soda,
is said to harden it, improve its colour, and give a
peculiar unctuous feeling to the water.
Srfl soap. Soda or hard soaps differ from potash
or soft soaps, chiefly by the manner in which they
combine with water. In the one, the water is chemi-
cally combined; in the other, it is merely in a state
of mechanical mixture. In this country, soft soap is
usually made with whale, seal, olive, and linseed oils,
and a certain quantity of tallow, the object of which
is to produce white granulations of stearate of potash,
called jigging, from the resemblance to the granular
texture ‘of ‘a fig. These granulations are improperly
regarded as proofs of the good quality of the soap,
and- are on this account sometimes imitated by the
addition of starch, or slaked lime.

The lyes used ‘should be caustic, and'of different
strengths. A portion of the oil being poured into
the pan, is heated to the temperature of boiling water,
when the weaker lye is introduced. The mixture is
then gently boiled, and stronger lye occasionally
added, until the saponification is thought to be com~
plete ; this is judged of by the boiling becoming less
tumultuous, the froth subsiding, and the paste be-
coming transparent and thick. The process is thought
to be complete when the paste ceases to have an acid
taste, and when a portion, put out on a cool glass plate,
assumes the proper consistency. It is then packed in
casks for the market. The granulations above spoken
of do not usually appear till two or three weeks after
the soap has been made, and in warm weather not at
all. The general composition of soft soap is—in every
11 or 12 parts, alkali 1 part, fatty acids from 4% to
5 parts, water and impurities from 5 to 6 parts. The
deliquescent nature of this soap renders it impossible
to separate it from the lyes, as in the case of hard
soaps; hence the glycerine and saline impurities of
the lyes remain in the soap.
Some oils, such as hempseed oil, impart to the soap
a greenish colour which is much esteemed. Manu-
facturers are always skilful in preserving appearances
which form the popular test of the ‘goodness of an
article, and hence this greenish hue is imparted to
soft soap by the addition of a little indigo.
Soft soap is largely ‘used for cleansing woollen
yarns and for stuffs, and also in linen bleach-works.
Its applications in the laundry are very limited.
Toilet soaps are usually prepared by remelting and
clarifying, curd or white soap, and adding various
perfumes, colours, &c. The restrictions of the Excise
have hitherto rendered it very inconvenient to make
toilet soaps directly from the requisite ingredients as
of course is done on the continent. In Ireland, where
there is no soap duty, the perfumer generally makes
his own soap by the cold process. The marbling of
fancy soaps is produced by rubbing up the colouring
material, such as Vermilion or ultramarine, with a little
olive oil or soap, and taking a small portion on a pal-
lette knife, it is pushed through the melted mass, and
moved about according to the taste of the operator.
Coloured soaps are produced by mixing mineral colours
with the melted mass: the pink colour of rose-soap is
produced by Vermilion: blue, by means of artificial
ultramarine; and brown, by means of various ochres.
Transparent soap is made from white tallow soap, cut
into shreds, dried, and heated in a still, with an
equal weight of spirits of wine, with turmeric, or
archil. When the spirit is saturated, the heat is
withdrawn, and the solution left to settle. It is then
poured into tin frames to solidify, and after exposure
to dry air for a ‘few weeks, is cut up into cakes for
sale.
The cakes, or tablets, are formed by placing a soft
mass of soap in a mould fixed in a lever-press: the
mould consists of a top and bottom die fitting into
a loose ring: by a sudden pressure the shapeless mass
assumes the form of the ring, and is embossed on the
top~ and bottom. Soap is ornamented with coloured
SOAP—SODIUM.
643
cameos by first forming the cake at a press, which
makes depressions for the reception of the differently
coloured soap, which is put in by hand, and the
coloured portion is embossed at a second press.
Windsor soap was formerly manufactured with
mutton fat or suet. On the continent the makers
mix with the fat, olive oil or tallow in the proportion
of 20 to 35 per cent. The saponification being com-
plete, the perfumes are added in the proportion of 9
parts per 1,000. They consist of oil of caraway, 6
parts; oil of lavender, 15 part; oil of rosemary, 15
part. Or, to every 1,000 parts of soap, add 6 parts
oil of caraway and 2 of bergamot.
Notwithstanding the obstruction occasioned by the
excise laws, the manufacture of soap is more exten-
sive in the United Kingdom than in any other country
of the world. In 1850 there were 329 soap~makers,1
and 68 remelters or perfumers. Ireland, not being
subject to duty, the quantity there made cannot be
ascertained, but in Great Britain the quantity made
in the above year amounted to 204,410,826 lbs., and
yielded a duty of 1,299,232Z. 10s. 26!. Of this quan-
tity, 12,555,493 lbs. were exported to foreign parts,
the drawback on it being 82,308Z. 188. 9d. The
total quantity consumed in Great Britain, therefore,
amounted to 191,855,333 lbs. Of this quantity,
22,858,382 lbs. were used by manufacturers of wool-
lens, silk, and cotton, on which the duty, amounting
to 97,342Z. Os. 110?. was remitted. This leaves the
net revenue derived from the soap-duty at 1,119,58ll.
10s. 6d. After deducting the quantity exported, andthat
used by manufacturers, it appears, that 168,996,95llbs.
were consumed for domestic use in Great Britain in
1850, equal to 8lbs. 1 oz. each person. In the year
ending 5th J an. 1852, there were manufactured in
Great Britain 195,077,499 lbs. of soap. Of this
quantity England produced 182,714,166lbs., and
Scotland 12,363,333 lbs. In England the quantity
is made up of hard soap, 169,519,2011bs.; sz'Zz'caz/‘ed
soap, 1,320,033lbs.; and soy‘? soap, 11,874,932 lbs.
In Scotland, hard soayo, 15,206,064 lbs. ; sz'lz'caterl soap,
7,1501bs. ; soft‘ soap, 7,150,119 lbs. The quantity
imported into Great Britain in the above year was,
from foreign countries, 1,533 cwts. 3 qrs. of hard soap,
158 cwts. lqr. of soft soap, and 57 cwts. 3qrs. of
Naples soap: from Ireland, 120,109 lbs. of hard soap,
and 1,714 lbs. of soft soap. The total amount of
import duty was 1,807 Z.
The excise duty was first imposed in Great Britain
in 1711, the rate being 1d. per lb. In 1713 it was
raised to Ila—(Z. per lb. ; and in 1782, the duty on hard
soap was raised to 24d, and on soft soap lid. per lb.
In 1816, the duty on hard soap was raised to 3d.
per lb., which continued until 1833, when it was re-
duced to lad. per lb. on hard, and 1d. per lb. on soft
soap. An addition of 5 per cent. was afterwards
made to these rates. At the time we are writing,
July 1853, a bill is being passed through parliament
for the total repeal of the soap-duty.
( 1) The number of licensed makers has progressively decreased
since 1801, when it was 624. In 1811 it was 522; in 1845, 355.
The reason for this decrease is probably the gradually extend-
ing operations of some of the large manufacturers.

The effect of the excise regulations has been to
prevent improvements in the manufacture, and to ex-
clude it from most foreign markets, by limiting the
manufacturer as to the size of the bars, the specific
gravity, the choice of materials, and the mode of ma-
nufacture. But notwithstanding these obstructions
it is gratifying to learn from the Jury Report, that,
on comparing the productions of other nations with
those of the seven soap-makers who represented the
British manufacture, “ it is evident that, as regards
tallow, palm-oil, and rosin soaps, the British soaps
are generally better manufactured. The English
toilet soaps are in no respect inferior to those of other
countries, and are generally so far superior in their
detergent qualities, on account of their being made
from soap manufactured exclusively by the large-
boiler-process. The high reputation of the so called
Windsor-soap in all civilized states, is an ample testi-
mony of the estimation in which English toilet-soap
is held by the makers of other countries, who adopt
its name for any sort they wish particularly to recom-
mend.”
SOAPSTONE. See Srna'rrrn.
SODA. See SODIUM.
SODA-WATER. See WATERS MINERAL.
SODIUM (Na 24) or NATRIUM, the metallic basis
of soda, was discovered by Sir H. Davy shortly after
the discovery of potassium, and by similar means.
[See Pornssiun] It may be prepared by decomposing
carbonate of soda by means of charcoal at a high
temperature. The process is similar to that described
for obtaining potassium from potash ; but as sodium
does not combine with carbonic oxide the process
is more productive. Thus 1 lb. of carbonate of soda,
obtained by calcining the acetate, mixed with % lb. of
finely powdered and % lb. of coarsely powdered char-
coal, and heated in a malleable iron bottle, yields
nearly 5 ounces of sodium, a result still capable of
improvement, the whole of the sodium present being
about 7 oz. Dr. Gregory remarks, that “from the ex“
treme cheapness of carbonate of soda and the produc-
tiveness of the operation, sodium can be prepared
far cheaper than potassium, and may in most cases
be substituted for that metal, as its affinities are
almost equally powerful. Should this metal ever be
required on the large scale, it might be obtained for
a price little, if at all, higher than that of zinc.”
Sodium is a metal of a silver-white colour, of the
sp. gr. ‘972: it is soft at common temperatures: it
fuses at 194°, and oxidizes very rapidly in the Placed on the surface of cold water it decomposes a
portion of that liquid with violence, but does not take
fire on account of its rapid motion and consequent
cooling. It takes fire in a solution of gum or starch,
which prevents its rapid motion. It also burns on
hot water with a bright yellow flame: it also ignites
on a moist badly conducting surface. A solution of
soda is formed by the combustion in water.
There are two well-defined compounds of sodium
and oxygen, the [motorcade or aszky/d'roas soda, NaO,
and the peroxide, N20,, or, according to some autho-
rities, NaOa. They resemble the corresponding com-
T r 2
644
SODIUM. .
pounds of potassium. The protoxide is the salifiable
base.
The lzpolralc of soda, NaO, HO, is prepared by
decomposing a rather dilute solution of carbonate of
soda by means of hydrate of lime. The process is
similar to that described for forming hydrate of
potash, and like that salt may be obtained in crystals
from its concentrated aqueous solution. The solid
hydrate of soda is a white, brittle, fusible substance,
of the sp. gr. 20: it is deliquescent, but, in time,
dries up again in consequence of the absorption
of carbonic acid. The solution is highly alkaline or
caustic, and a powerful solvent for animal matter: it
is used in vast quantities for making soap. [See
SCAR] The strength of a solution of caustic soda
may be determined by approximation from a know-
ledge of its density by the aid of the following table,
prepared by Dr. Dalton :--
Sp. Gr. Soda per cent. Boiling point.
1'85 63'6 600Q
1'72 53 8 . 400
1'63 46'6 .. 300
1'56 41‘2 280
1'50 36'8 265
1'47 34'0 255
1'44 . 31'0 248
1'40 . 29'0 242
1'36 26'0 235
1'32 23‘0 228
1'29 19'0 224
1'23 16'0 . .. 220
1'18 13'0 ................ .. 217
1'12 9'0 ................ .. 214
1'06 ................ .. 4'7 ................ .. 213
A more perfect method of ascertaining the quan-
tity of real alkali in the hydrates and carbonates of
the alkalies is given under ALKALIMETRY.
Carbonate of soda, NaO, CC, + 10 HO. This salt,
so important to our manufacturers [See GLASS—SOAP,
&c.], which is now prepared in vast quantities from
common salt, was formerly obtained by the combus-
tion of certain sea-shore and sea plants, the ashes of
which afforded, by lixiviation, an impure kind of soda.
Two kinds of rough soda were’ known in commerce,
viz. barilla and lcelp, the former being the semifused
ash of the salsola socla, which was cultivated on the
Mediterranean shore of Spain, near Alicant. Impure
carbonates named Varec and Blarzgaelle were made,
the form er in Brittany, and the latter at Aigue-mortes
and Frontignan. At Narbonne it was called salicor.
Kelp consists of the ashes of sea-weeds, collected
upon many of the rocky coasts of Britain, and burnt
in kilns or in excavations made in the ground. About
24 tons of sea-weed are required to produce 1 ton of
kelp. Kelp is now only of importance as a source of
iodine. [See Ionnvn] During the war, however,
when the duties on barilla and common salt were
exceedingly high, the manufacture of kelp was a
flourishing one in Scotland. The annual rental of
the kelp shores of the island of North Uist alone
amounted ‘to 7,000l. Scotland at one time furnished
annually 25,000 tons of kelp, which has been known to
sell for 20l. a ten: the usual price was about half that
sum. .Nalz'oe carbonate of soda is also produced in
Egypt, in the desert of Thaiat in the western Delta,

where there is a pit 4a leagues long and a 7}- of a
league wide, which, during winter, is filled to the
height of 6 feet with violet coloured water. On the
evaporation of this water, carbonate of soda remains,
and is loosened with iron poles. The residue is con-
taminated with 36 per cent. of common salt, and
16 per cent. of sulphate of soda, besides sand; but
after being purified it contains only 10 per cent. of
sand, 4 of common salt, and 1 of sulphate of soda.
At Shegedin, in Little Cumaria in Hungary, carbo-
nate of soda effioresces on the ground. It is gathered
before sunrise: the grey powder is dissolved out by
water, the solution evaporated to dryness, and the
residue heated to redness for the purpose of destroy-
ing organic matter. It contains sulphate of soda and
common salt. Carbonate of soda also efiloresces
abundantly on walls. That found on walls in the
towns of Flanders consists of carbonate and sulphate
of soda, and is derived partly from the soda-salts in
the limestone used in the preparation of the mortar,
and partly from soda contained in the coal with which
this limestone is burned.
Previous to the revolution of 17 89 the soda used
in France was obtained from marine plants, as above
described, chiefiy from the coast of Spain. The wars
in which France was engaged with nearly all Europe
put a step to this and other branches of native in—
dustry. The importation of potash was also stopped,
and all the supplies of that substance that could be
obtained in France were devoted to the manufacture
of gunpowder. The manufacturers of glass, soap,
850., were thus deprived of an article essential to their
very existence. In this emergency the Committee of
Public Safety called upon all citizens to place in the
hands of Commissioners, without any regard to private
interests, any plans for the preparation of soda that
might be known. This was accordingly done, and
the Commissioners reported, that among the numerous
plans submitted to them, that by Leblanc was most
practicable, and best adapted to the wholesale deal-
ings of the manufacturer. This plan was adopted,
and the first establishment for carrying it out was
erected at St. Denis in 1804. After the repeal of the
salt duty, the process was introduced into this coun-
try, and altogether it has been in use for nearly half
a century with little or no alteration in its most
important details.
The first part of the process consists in converting
common salt, NaCl, into sulphate of soda. This is
done in reverberatory or clecomposz'agfarrzaces, as they
are called, two of which are shown in Figs. 2002,
2003, the first being the more common, and the second
the more improved form. A number of these fur-
naces are arranged side by side, all discharging their
fines into a tall chimney, which is the most con-
spicuous object on approaching the alkali works from
a distance. The floor, or sole of each furnace is of
brick, but is sometimes lined with lead, and is usually
divided into two compartments, in one of which the
liquid portion of the mixture is evaporated, and in
the other the residuary sulphate is calcined. In
some furnaces the evaporation and calcination are
SODIUM.
645
carried on in the same division. In fig. 2002, in the
division B, farthest from the fire, called the decomposing
becl, the salt and sulphuric acid are brought together.
\‘rjttja ill
. l‘
in?) uilhjlllllllll f f
it
___-_-


A _.__.r-
___.W


;j 1 :11]
ll
waflfluwlqr-EL—J




_ \$\ '5’:
., i t x
I.‘ .\\\§\ 2 ‘,
\~\---\~\' ‘N ‘\‘\ "\\ l ussssssssssssws \\
.i
s. u
it
If" ‘ I
\
Eli
1.,
p


Q I I
: a. it;
it?"-
~—.<.—__- It’ :
,__-_’4 \ “r
‘ \ ' .' \\'\“\“\. .v
‘ \ \ s
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w;
Fig. 2002.

,‘.
\


. i _ ~. ,, ..
.\\ William 1 lillllilllllll ,vhhrviri
\ lillll- ‘ l“!
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Fig. 2003.
a ' ~..
.-.~:- —-‘~ _' Jije‘fi‘é'i‘


The quantity of salt introduced at one charge varies,
according to the size of the furnace, from two or
three cwt. to half a ton. A nearly equivalent weight
of sulphuric acid is poured very slowly on the salt
through an opening in the roof, closed at other times
with aleaden plug, or through aleaden syphon funnel
f; as in the figure. The quantity of acid is so ad-
justed that the salt may be in excess, which is far
more desirable than an excess of acid. The mixture
is equalized by stirring with an iron rake covered with
sheet lead. Abundant fumes of hydrochloric acid
result from the decomposition, which are conveyed
through the flue into the chimney, and discharged
into the air, or they are condensed into liquid hydro—
chloric acid; but as the consumption of this acid
bears only a small proportion to that of soda, it is
generally more profitable for the manufacturer to
allow the acid fumes to escape into the air, where, on
emerging from the top of the chimney, they form a
white cloud of acid, which rains sterility and desola-
tion on the surrounding country. Many alkali works
have been indicted as nuisances on this account.
Attempts were made to remedy the evil by discharg-
ing the fumes higher in the air, where it was supposed
that the great dilution, by combining with atmospheric
vapour during their descent, would render them com-
paratively harmless. This is the origin of those won—
derful chimneys, such as that of Muspratt, 4195 feet
high, and 30-12— feet in its lower, and 11 feet in its
upper diameter, and containing a million of bricks in
its structure; while the chimney of Tennant’s soda
works at St. Rollox, near Glasgow, is of still larger
dimensions. These costly structures have not been
found to answer the purpose for which they were in—
tended, so that it has been necessary to condense the
gas as fast as it is discharged from the mixture of

salt and sulphuric acid.1 But to return to the decom-
posing furnace. In about two hours the fumes cease
to be copious, and the residuary sulphate of soda
becomes a pasty mass. This is now pushed out of
the decomposing bed through an opening a, in the
bed of the furnace, into a vault e, which opens into
the chimney, so that the workmen are not exposed
to the suffocating acid fumes. Another charge is then
immediately introduced, and the decomposition goes
on as before. The product of the first charge having
cooled down, so as not to produce acid fumes, is next
shovelled into the other compartment of the furnace
nearest the fire, called the roasting Zzeil n, where it is
exposed to a greatly increased temperature, which in
an hour or two dissipates all the remaining muriatic
acid. During this operation it changes from yellowish
to white. It is now called salt ealee, and is raked out
to make room for another charge.
The object of the next process, which is the most
important in the manufacture of soda, is to convert
the salt cake or sulphate of soda into carbonate of
soda, which is done by heating it to redness, with
charcoal and carbonate of lime. By the original
method, 100 lbs. of salt cake were mixed with the
same weight of chalk and 55 lbs. of charcoal, all
ground to a coarse powder, and well mixed by sifting.
But as in this country wood-charcoal is too expensive
to be used for the purpose, small coal is substituted,
and the carbonate of lime may be either in the form
of limestone, or chalk. The charge, amounting to 2
or 2% cwt., is heated in a reverberatory furnace, called
the blae/e-as/ifamaee ; this is oval in shape, and about
10 feet long in the sole, all corners being avoided, in
order that no portion of the charge may escape the
action of the fire and the stirring rods. The sole is
divided into two parts, one of which, the farthest
from the fire, is higher than the other part. The first
division is the preparing bed, in which the charge is
first heated, to avoid cooling the furnace. The second
division, called the flaming bed, is slightly concave.
The proportions of the salt cake, coal, and car-
bonate of lime, as well as the weight of the charge,
vary at different works. The charge is shovelled in
upon the preparing bed, and spread evenly; when
sufiiciently heated, it is transferred, by means of an
iron tool shaped like an oar, to the fiuxing bed, which
should be at a full red heat. As soon as the mixture
is ignited, and begins to clot on the surface, it is

(1) Patents have been taken out at various times for contri-
vances for condensing the acid fumes, and converting them to
some useful purpose. In one contrivance, the chimney is filled
with rounded flints, and in another with coke, kept constantly
wet by a. small stream of water from the top; and the acid thus
condensed by exposure to an extensive humid surface is conveyed
along apipe at the bottom of the chimney, into a subterranean
reservoir. In another arrangement, the condenser consists of a
series of upright channels or dues, in which the fumes alter-
nately ascend and descend: water falls into these channels from
above, and is distributed over boards placed obliquely. Or by
another contrivance water is admitted at the bottom of the con-
denser in the form of a fountain. In some works the acid fumes
from the salt, instead of being condensed, are advantageously
employed in the manufacture of bleaching powder (chloride of
lime); in other works the condensed acid is employed to generate
carbonic acid from limestone, for the manufacture of bicarbonate
of soda, or of carbonate of magnesia.
6416
SODIUM.
turned cautiously over by the car or spreader, so as
constantly to expose a fresh surface to the fluxing
action of the fire ; care being taken not to raise the
lighter portions into a dust, or they would be carried
away by the draught of the furnace and wasted.
When the whole mass has a doughy consistence,
chemical decomposition begins; jets of sulphuretted
hydrogen, and carbonic oxide, called candles by the
workmen, escape from various parts of the mass,
which is now sedulously worked about with the
spreader and an iron rake. At length the mass of
soda melts, and from the rapid escape of gas, appears
to boil. It gradually settles down, and when all the
“candles” have disappeared, the mass is raked out
into cast-iron troughs or iron wheelbarrows, where it
becomes solid, and forms a mixture of what is called
black-ash, with ball—soda, or British barz'lla. A second
charge is then shifted from the preparing to the flux—
ing bed, and a third charge immediately placed on the
preparing bed. In some large works a ton of the
mixture is thus worked off in six hours.
The chemical changes which take place in the above
process are somewhat complex, but the most impor-
tant may be stated thus z—The sulphate of soda, by
calcination with the coal, loses its oxygen, and be-
comes converted into sulphuret of sodium; the car-
bonate of lime and the sulphuret of sodium then act
upon each other, the oxygen of the lime converting
the sodium into soda, and the carbonic acid of the
lime uniting therewith to form carbonate of soda,
while the sulphur of the sodium unites with the cal-
cium of the lime to form sulphuret of calcium?l This
last—named substance, called soda waste, is a source of
great annoyance to the manufacturer; it is bulky, and
applicable to no useful purpose yet known: Vast
heaps of it accumulate in the neighbourhood of
alkali works, often making it necessary to purchase
land merely to accommodate it. Attempts have been
made to recover the sulphur from it, but hitherto the
cost has exceeded the value of the sulphur re-
gained.
The next process is to separate the soluble matters
from the black ash. A ball of about Scwt. as it
leaves the black ash furnace, affords an average of
1:1- cwt. of soda ash. The insoluble ingredients con—
sist of carbonaceous matters, carbonate of lime, and
a compound of lime and sulphuret of calcium. The
soluble ingredients are carbonate of soda, a little un-
decomposed sulphate of soda and ‘common salt, some
caustic soda, and a few other ingredients. The sepa-
ration of these matters is the first step towards the
preparation of pure soda from black ash, and this is
effected by reducing the mass to fragments, either by
crushing it under mill-stones, or by exposing it to the
vapour of water, which causes it to swell up and fall
to pieces. The fragments are put into iron vats, and
covered with warm water. In 10 or 12 hours the
(1) The reactions may be thus represented :—
Sulphuret of Sulphur


Sulphuret of
Sodium. Sodium \ 7 Calcium.
Carbonate of Lime {Calcium (
Lime. .Oxygen \i
Carbonic acid , - Calbonate of soda.

solution is drawn 0d’, and the residue washed 6
or 8 times successively, either with fresh water,
or with the washings of other vats. The lye thus
obtained is evaporated to dryness in leaden pans, (or
first in the iron vessel I, Fig. 2003, and then in V,) by
which a carbonate of soda is obtained, mixed with a
little caustic soda and sulphuret of sodium. This is
further purified by mixing it with about one-fourth of
its weight of sawdust or coaldust, in a reverberatory
furnace, when the sulphuret of sodium parts with its
sulphur, and becomes converted into carbonate of
soda. In some cases the sawdust or coal is omitted,
and the calcination carried on in what is called the
w/zz't‘e—as/zfawzace. When the liquid assumes the con-
sistence of mortar, it is raked into a large iron vessel,
with a false perforated bottom, to allow the mother
liquor to drain off from the crystals. The drained
mass is then put into a finishing furnace, and mode-
rately calcined, being worked about in all directions,
so as to bring every part within the flame, and in
contact with air. The residue of this operation when
ground under mill-stones, is the white ask or soda ask
of commerce, and is sufiiciently pure for most of the
manufacturing applications of soda; but for the
manufacture of plate glass, and for furnishing crys-
tals of carbonate of soda, the ash is rendered still
purer by another calcination at a moderate heat. For
the crystalline carbonate, the purified ash is dissolved
in hot water to saturation, and the solution run into
large cast-iron pans. The soda separates in large
well-formed crystals, which are broken up, and the
mother liquor allowed to drain oif. These crystals
are carbonate of soda, nearly pure: 100 parts contain
21'81 soda, 1543 carbonic acid, and 6276 water;
when exposed to air they fall to powder; boiling
water dissolves more than an equal weight of them.
The mother liquor which drains olf contains nearly
the whole of the foreign salts, and is evaporated to
dryness: the residue generally contains about 30 per
cent. of alkali, and serves the purposes of the crown
glass and soap manufacturer.
Bicaréoaazfe of soda, Na0,002 + 110,002. is pre-
pared by passing carbonic acid gas into a cold solu-
tion of the neutral carbonate, or by exposing the
crystals to an atmosphere of the gas. The gas is
rapidly absorbed, and the crystals lose the greater
part of their water, and become converted into the
bicarbonate. It is a crystalline white powder: it
cannot be dissolved in warm water without partial
decomposition. It is soluble in 10 parts water at
60°, and the liquid has a feebly alkaline reaction, and
a milder taste than that of the simple carbonate.
By exposure to heat it is converted into the neutral
carbonate. Sesgaz'carboaaz‘e of‘ soda, 2NaO,3COi +
étHO, like the sesquicarbonate of potash, cannot be
formed at pleasure. It occurs native on the banks of
the soda lakes of Sakena, in Africa, whence it is
exported under the name of z‘roaa.
Sulphate of soda, NaO,SO3 + lOHO, or Glaader
Salt, is a refuse product in several chemical opera-
tions. It may be prepared pure by saturating a
solution of carbonate of soda with dilute sulphuric
SODIUM. ,
647
acid. The form of its crystals is derived from an
oblique rhombic prism; the crystals efiioresce and
fuse by heat in their water of crystallization; they
dissolve in twice their weight of cold water; at
915° Fahr. which is the maximum of solubility, 100
parts water dissolve 322 parts of the salt. If heated
beyond this point the solubility diminishes, and a
portion of the salt is deposited. This salt has a
slightly bitter taste, and is purgative: it is found in
some mineral springs, as at Cheltenham. There is a
hz'snlphate (ya soda, containing NaO,SO;, + HO,SOs +
3H0. Hpposatphtte (f soda, Nil-0,8202, is largely
used in photographic processes. [See Pnoroennrnm]
It may be found in various ways. According to
Fownes, one of the best methods is to form neutral
sulphite of soda, by passing a stream of well washed
sulphurous acid gas into a strong solution of car-
bonate of soda, and then to digest the solution with
sulphur at a gentle heat during several days. By
careful evaporation at a moderate temperature, the
salt is obtained in large and regular crystals, which
are very soluble in water.
Nitrate ry" soda, or onhz'o nitre, NaO,NOs, occurs
native in great abundance at Atacama in Peru, where
it forms a regular bed, covered with clay and alluvial
matter. The pure salt commonly crystallizes in
rhombohedrons; it is deliquescent, and very soluble
in water; it is used for making nitric acid, and also
as a top-dressing in agriculture.
There are several phosphates of soda; the common
tribasic phosphate, 2NaO,HO,I?Os + 24110, is a
beautiful salt; it may be prepared by precipitating
the acid phosphate of lime, obtained by decomposing
bone-earth by sulphuric acid with a slight excess of
carbonate of soda. Its crystals are oblique rhombic
prisms; they are soluble in 4 parts of cold water, and
the solution is alkaline; the salt is bitter and purga-
tive. Crystals containing 14 equivalents of water
have a different form from the above. By adding a
solution of caustic soda to the common tribasic phos-
phate, a second tribasic phosphate, also called snh-
phosphate, is obtained. It contains 3NaO,PO, +
24110. Its crystals are slender six-sided prisms,
soluble in 5 parts of cold water, and its solution is
strongly alkaline. This salt is decomposed by acids,
even by carbonic acid. The effect of heat is to deprive
it of its water of crystallization. A third tribasic
phosphate, called also saperphospate, or htphosphate,
NaO,2HO,PO5 + 2110, is obtained, by adding phos-
phoric acid to the ordinary phosphate. Trz'hasz'o
phosphate of soda, ammonia and water, NaO,NH4O,
H0305 + 8110, has been noticed under its trivial
name [See MICROCOSMIO SALT]. It may be prepared
by heating 6 parts of common phosphate of soda
with two of water, until the whole is liquefied; 1 part
of powdered sal-ammoniac is then added; common
salt separates, and may be removed by filtration, and
the new salt is deposited from the concentrated solu-
tion in prismatic crystals, which may be purified by a
second or a third crystallization. Microcosmic salt
is very soluble. When the salt is gently heated it
parts with 8 equivalents of water of crystallization,

and at a higher temperature the water in the base
is expelled, and also the ammonia; metaphosphate of
soda remains; it is very fusible, and forms a useful
flux in blowpipe experiments. Bz'hasz'c phosphate of
soda, 2NaO,PO, + 10110, also called pyrophosphate of
soda, is prepared, by strongly heating common phos
phate of soda, dissolving the residue in water, and
re-crystallizing. The crystals are brilliant, permanent
in the air, and less soluble than the original phos-
phate. Monohasz'e phosphate of soda, NaO,PO,, also
named metaphosphate of soda, is obtained by heating
either the acid tribasic phosphate, or microcosmic salt,
as already noticed. It is a transparent glassy com
pound, fusible at a dull red heat, deliquescent and
very soluble in water. It does not crystallize, but
dries up into a gum-like mass.
Bz'horate 0]" soda, NaO,2BOs +10HO, has been
noticed under BORAX.
Snlpharet of Sodium, NaS, may be prepared in the
same manner as the monosulphuret of potassium
[See POTASSIUM]. It separates from a concentrated
solution in octohedral crystals, which are quickly
decomposed in the air, into a mixture of hydrate and
hyposulphite of soda.
Chloride g” Sodium, NaOl, or common salt, is the
only compound which sodium forms with chlorine.
This substance, so important in domestic economy,
agriculture and the arts, is very abundant in nature,
and exists under various forms.1 The waters of the
ocean contain common salt as their chief saline ingre-
dient, and in countries far removed from the ocean,
vast stores of roots-salt, or sat-gem, exist at a moderate
depth beneath the surface. The compound is very
stable; it may be fused at a red heat, and on being
cooled, concretes into a hard white mass without
change. At a bright red heat it sublimes in the air
without decomposition, and tinges flame of a blue
colour. It is insoluble in alcohol, but dissolves in
small quantities in the watery portion of proof spirit.
It is scarcely more soluble in hot than in cold water.
According to Gay Lussac, 100 parts of water at 58°

(1) Dr. Pereira, in his Materia Medica, has the following
observations on the use of salt as a condiment to food :—
“ The existence of a greater or less appetite for it in all indi-
viduals, appears to me to show that this substance must serve
some more important uses in the animal economy than that of
merely gratifying the palate. In considering these, we observe,
in the first place, that it is an essential constituent of the blood,
which fluid probably owes some of its essential properties to its
saline matter. Now, as the blood is constantly losing part. of its
saline particles by the secretions, the tears, the bile, 8zc., the
daily loss is repaired by the employment of chloride of sodium as
a condiment. In the second place, the free hydrochloric acid
found in the stomach, and which forms an essential constituent
of the gastric juice, is obviously derived from the salt taken with
our food. Thirdly, the soda of the blood and some of the secre-
tions is doubtless obtained from the decomposition in the system
of common salt. These are some (probably only a portion) of the
uses which chloride of sodium serves in the animal economy. It
deserves especial notice, that while salt is thus essential to health,
the continued use of salted provisions is injurious. But their
noxious quality is probably to be referred rather to the meat,
whose physical and chemical qualities are altered, than to the
presence of the salt; though we can readily conceive that an ex—
cessive use of salt, or of any other article of food, will be followed
by injurious consequences. However relishing salted fish (as
anchovies, herrings, cod, 850.) may be, they are difiicult of
digestion.”
648
SODIUM.
dissolve 36 parts of salt; [at 140°, 37 parts, and at-
225°, which is the boiling point of a saturated solu-
tion, 100 parts of water dissolve 4038 parts of salt.
At 32° water dissolves rather more salt than at 60°.
According to Fuchs, pure chloride of sodium is
equally soluble at all temperatures, 100 parts of
water dissolving 37 of salt. The ice, which forms at
low temperatures in salt-water, is itself free from salt,
a property taken advantage of in some cold countries
in the manufacture of salt.1 Pure salt does not alter
by exposure to the air, but as it generally contains
minute portions of other salts, which absorb moisture,
common salt is usually more or less deliquescent.
The form of the crystal, if obtained by slow sponta-
neous evaporation, is a solid cube, but when procured
at a boiling heat from the surface of a solution, the
crystals are very small, form-
ing together in groups, so as
to present hollow 4-sided py-
‘ ramids, the sides of which
are graduated in steps, as
Fio- 2°04- shown in Fig. 2004, in conse-
quence of the small lines of cubical crystals gradually
retreating inwards. Regnault imagines one of these
groups to be formed in the following manner :—
Suppose a small cubical crystal to be formed on the
surface of the solution; this crystal tends to sink to
the bottom of the solution, by virtue of its superior
density, but is prevented from doing so by the action
of capillary attraction, as shown at a, Fly. 2005.




Fig. 2005.
Other crystals are quickly formed around the first,
and these attach themselves to ‘the four upper edges
thereof, and form a hollow 4-sided frame above the
first cube ; the group descends in the liquid, as shown
at l) ; new crystals form along the upper and outer
edges of the first frame,.thus forming a second hollow
frame as at 0; another frame forms on the second,


and so on, as represented in d, and in this way the
group enlarges chiefly at the surface of the liquid,
which'would be likely to be the case, since the salt,
being equally soluble, whether hot or cold, does not
tend to deposit crystals on cooling, but only on the
evaporation of the liquid, which takes place at the
surface alone. In the above description it is assumed
that only a single row of cubical crystals forms round
the outer horizontal edges of the frame previously
formed; but it is possible that 2, 3, or 4 rows may
be formed in the same horizontal plane, which would
be the case if the group did not descend in the liquid
as soon as one row of crystals was formed along
each of the 4 edges. In this way the heights of the
hollow pyramids may vary with respect to the area of
their basis, according as the liquid is more or less
tranquil, and the capillary action more or less ener-
getic.
The following excellent description of the crystals
of common salt is from Bergmann’s Chemical Essays :——-
“ These cubes exhibit diagonal markings or striae,
but frequently 011 each side produce squares parallel
to the external surface, gradually decreasing inwards ;
circumstances which show the ves-
tiges of their internal structure:
for every cube is composed of six
quadrangular hollow pyramids,
joined by their apiece and external»
surface; each of these pyramids
filled up by others similar, but
gradually decreasing,completes the
form. By a due degree of evaporation it is no difficult
matter to obtain these pyramids separate and distinct;
or six of such, either hollow or more or less solid, joined
together round a centre. If we examine the hollow pyra-
mid 2 of salt farther, we shall find it composed of four
triangles, and each of these formed of threads parallel
to the base; which threads, upon accurate examina
tion, are found to be nothing more than series of small
cubes.”
The antiseptic properties of salt are not well under-
stood. It is usual to ascribe them to the clrpz'rzg
influence of the salt. “ A dry bladder remains more
or less dry in a saturated solution of common salt.
The solution runs off its surface in the same manner
that water runs from a plate of glass besmeared with
tallow. Fresh flesh, over which salt has been strewed,
is found after 24 hours swimming in brine, although
not a drop of water has been added. The water has
been yielded by the muscular fibre itself, and having
dissolved the salt in immediate contact with it, and
thereby lost the power of penetrating animal sub—
stances, it has on this account separated from the
flesh. The water, still retained by the flesh, contains
a proportionally small quantity of salt, having that
degree of dilution at which a saline fluid is capable of
penetrating animal substances. This property of
animal tissues is taken advantage of in domestic eco-
nomy, for the purpose of removing _so much water


Fig. 2006.

(1) Some experiments by Dr. Faraday show in a remarkable
manner how completely foreign substances, such as colouring
matter, salts and alkalies, are expelled from water by the opera-
tion of freezing. A solution of sulphate of indigo was partially
frozen in a glass test tube; for which purpose the tube held in
the left hand was moved about in a. freezing mixture, while a
feather held in the right hand was moved about in the tube, in
order to separate the particles of air, and to keep the particles of
'water, acid, and colouring matter in gentle agitation, so as to
assist their separation during the crystallization of the particles
of water. In this way the tube was in the course of a minute or
two lined with ice, and the‘ whole of the unfrozen colouring
.matter collected down the centre or axis of the tube: on
pouring-this ofi‘, rinsing the tube with pure water, and taking out
the me, it was found to be perfectly transparent, the whole of the
intensely blue colouring matter having been rejected in freezing.
' Dilute sulphuric acid and dilute ammonia were treated in a. similar
manner, ‘and the water was frozen, the acid being collected along
the central line in one case, and the alkali in the other.
(2') The bases and altitudes of these little ‘pyramids are in general
equal : thus showing the disposition of the salt to form a. cube..
* SODIUM.
649
from meat, that a sufficient quantity is not left to
enable it to enter into putrefaction.n1
Salt, in moderate quantities, is useful as a fer-
tilizer,2 and, indeed, exists in nearly all soils :- it is
found in the ashes of all plants, but especially in the
ashes of marine plants, and is sometimes borne with
the spray of the sea to great distances inland'when
the winds are strong and the waves high and broken.
On some rocky shores, the spray may be seen occa-
sionally moving up the little coves and inlets in the
form of a distinct mist, driving before the wind, and
the saline matter has been known to traverse nearly
half the breadth of our island before it has been en-
tirely deposited from the air. Hence, in those cases
in which the use of common salt has failed to benefit
the land in particular localities, it must be evident
that the soil in these places already contained a natu~
ral supply of this compound, large enough to meet
the wants of the crops which grew upon it. The
influence of the wind in top-dressing the exposed
coastline of a country with a solution of salt, may
serve as an important guide, both in reference to the
places in which it may be expected to benefit the
land, and the causes of its failing to do so in particu—
lar districts.3
Great Britain, which is so richly supplied with
almost every variety of mineral wealth, is furnished
with brine-springs and extensive beds of fossil salt.
The principal brine-springs are situated in the county
of Cheshire, in the valleys through which the Weaver
and the small rivulet the Wheelock have their course,
The springs do not appear to be strongly impregnated
with salt near the source at the Peckferton Hills, nor
until the river approaches Nantwich. At this place
there are numerous springs from which salt is manu-
factured. The brine-springs occur at various depths.
At Nantwich, the brine is met with about 10 or 12
yards from the surface, and in sinking for fresh
water, caution is required to avoid the brine. At
Winsford, it is generally necessary to sink from 55

(l) Liebig, Organic Chemistry.
(2) Mr. Johnson, in his “Farmer’s Cyclopaedia,” referring to
the agricultural uses of salt, laments that during several successive
reigns the duty on salt rendered it impossible for the English
farmer to become practically acquainted with its value in agricul-
tural operations. The duty originated as a war-tax in the ninth
year of the reign of William III. and was not removed until the
year 1823. The price of salt in consequence of the duty, was
raised from 6d. a bushel to more than 20s. Salt, as a manure,
was therefore known only in the traditions of the English farmers.
“ Through these they learned that it was formerly used to kill
worms and to destroy weeds; that it cleansed fallows, increased the
produce of light arable soils, and was good to sweeten grass.
These reported advantages were rendered more probable by certain
facts that had been forced as it were upon their attention. The
gardener was well aware that the brine of the pickling tubs when
poured over his heaps of weeds, not only killed every weed, every
seed, and every grub, but that these heaps were then converted
into so many parcels of the most fertilizing manure; the good
effects of which, especially upon potatoes and carrots, were very
decided. It was well-known too, that a single grain of salt placed
upon an earth-worm speedily destroyed it; that if brine were
poured upon the lawn, all the earth-worms were immediately
ejected from that spot; and that if it were sprinkled about over
a portion of the grass, to this salted portion all the deer, sheep,
or the horses of the park constantly repaired in preference to any
other part of the field.”
(3) Johnston: Lectures on Agricultural Chemistry.

to 60' yards ‘before it is met with, and then it is found
in great abundance, and it rises to within 12 yards
of the surface. 1 At Northwich it is found at a depth
of from 30 to 410 yards, and its level is about 20 yards
from the surface. At Wilton, Anderton, and Bamp-
ton, the brine is found at depths varying from 4.10 to
65 yards. The springs along the Wheelock generally
occur at greater depths, and are not so copious, some
of theni being occasionally pumped dry.
The brine-springs appear to have been worked from
the earliest periods in the history of this country,
but the beds of fossil or rock-salt, from which the
springs originated, were not discovered until the year
1670. These were first found about 34: yards from
the surface, while searching for coal in Marbury,
about a mile to the north of Northwich. The salt
was discovered in a bed 30 yards thick, and below it
was a stratum of indurated clay. This discovery'led
to' other attempts to find it; and on sinking a shaft
anywhere within half-a-mile of Marbury, it was met
with at about the same distance from the surface, if
the access to it was not prevented by brine or fresh-
water. No other rock-salt was discovered till the year
1779, when, in searching for brine near Lawton, it
was met with, about 42 yards from the surface. This
stratum was only A feet in thickness: below it was a
bed of indurated clay, 10 yardsthick 5 and inpene-
trating this, a second stratum of rock-salt, 12 feet in
thickness, was’ found. On continuing the sinking,
another stratum of clay, 15 yards thick, was passed
through; and below this was a third stratum of rock-
salt, which was sunk into to the depth of 24.‘ yards.
The lowest, 14 yards, being the purest; these only
were worked.
Hitherto no attempts had been made to find a lower
stratum of rock-salt in the neighbourhood of North-
wich; for as the one first met with was thick, and
furnished an abundant supply, there was no induce-
ment to sink deeper. The fear of meeting with springs
at a lower depth, which might impede the working of
the pits, prevented the attempt; but as no inconve-
nience of this kind had been experienced at Lawton,
where a much purer salt was found at a greater depth
than near the surface, the owners of one of the mines
near Northwich were led, in 1781, to sink deeper,
and to pass through the bed of indurated clay, below
the rock-salt which had been so long worked. This
clay was 10 or 11 yards in thickness, and immediately
below it, was found a second stratum of rock-salt, the
upper portion of which diii'ered but little in purity
from the higher stratum; but on penetrating into it,
from 20 to 25 yards, it was found to be much more
pure, and free from earthy admixture. This increased
purity, however, was observed for only 4: or 5 yards;
the shaft was sunk 141 yards still lower, but the pro—
portion of earth was the same as in the upper part of
the stratum. It was, therefore, thought useless to
proceed further. Several other proprietors of mines
in the neighbourhood also sunk shafts, and obtained
similar results.
In sinking for brine or rock-salt, the strata passed
through generally consist of clay and sulphate of
650
SODIUM.
lime (gypsum), mixed in various proportions; that
of the latter somewhat increasing as the shaft ap
proaches the brine or rock. The workmen1 call the
clay red, drown, or blue metal, according to its colour;
and the sulphate of lime they name plaz'ster. The
strata are in general close and compact, allowing
very little fresh water to pass through them. In some
places, however, they are broken and porous, and
admit so much fresh water into the shaft, that when-
ever this s/zaggy metal, as the workmen call it, has
been met with, it has been usual to discontinue any
attempts to pass through it. The steam-engine, how-
ever, has been since applied to pump out the water,
and the workmen have succeeded in sinking shafts
through this porous stratum, through the marl and
clay below it, and so into the beds of rock-salt.
On making a horizontal section of the bed of rock-
salt, various figures may be observed, differing in
form and size, some of them being nearly circular,
others more nearly oval, and a third set form an
irregular pentagon. Some are not more than 2 or
3 feet in diameter, others are 10 or 12 feet. The
lines which form the boundaries of these figures
are white, and from 2 .to 6 inches wide, and consist
of pure rock-salt without any earthy admixture. The
other portions have earth mixed with the salt in
various proportions, and the effect of the whole
reminds one of rude mosaic work. This disposition
is uniformly observed through the whole thickness of
the stratum _of rock-salt, wherever a horizontal section.
is made. The division between the lower portion of
the upper bed of rock-salt, and the indurated clay or
stone beneath it, is as exactly defined as that between
the upper portion of it and the earth above. In
‘passing through this stone, small veins of rock-salt
are found here and there, running in it in various
directions; and whenever a crevice occurs, this is
filled up with rock-salt, to which the clay and oxide
of iron have given a deep red tinge. The rock-salt
procured from the pits in the neighbourhood of North-
wich is from the lower stratum only. The shafts are
usually square, and constructed of timber. The rock-
salt is obtained in masses of considerable size, dif-
fering in form and purity. They are separated by the
usual operation of blasting, and with the aid of me-
chanical instruments. Before extending the work-
ings in any direction, care is taken to secure a good
roofing for the cavity which is to be formed. In
doing this, the men employ common picks, working
horizontally, so as to form a roofing of the rock, and
making this as plane as possible. From its situation,
(a few feet above the purer part of the stratum,) the
rock obtained‘d-uring this process is usually of inferior
quality, and is, for the most part, employed in the
refineries. ‘The depth of the workings from the
roofings depends, in great measure, on the nature of
the stratum, and the proportion of it occupied by the
rock of the purer quality; or, as it is termed, Fras—
sz'aa roe/7:, from the circumstance of its being largely

(1) The workmen are called wallers, from the circumstance of
their \raising a bank or a walling round the pit with the rubbish
of the works.

exported to the shores of the Baltic. The cavity thus
formed presents a striking appearance; and when
illuminated by candles fixed in the rock, the effect is '
highly brilliant. In some of the pits the roof is sup—
ported by pillars 8 or 10 yards square, which are in
general regularly disposed; others are worked out in
aisles. The rock-salt is raised to the surface by
steam power, but horses are employed underground
for conveying the rock to the bottom of the shaft.
The men employed in working the rock are paid by
the ton, and provide their own tools and gun-
powder.1
The brine was formerly raised in various ways:
first, by pumps worked by hand; secondly, in a few
situations which admit of the assistance of a stream
of water, a water-wheel was employed; t/zz'rdlr, by
horse power; fourt/zly, as the demand for salt in-
creased, small windmills were used for raising the
brine, and lastly, steam power has superseded all other
methods ‘of pumping. The reservoirs into which the
brine is pumped up are either large ponds formed in
clay and generally lined with brick, capable of con-
taining the consumption of several weeks, or they are
wooden cisterns pitched within, which will hold a
supply of brine for the consumption of a few days
only. The brines of the Cheshire springs contain a
large proportion of salt, but they are not always com-
pletely saturated; and, as it is important not to
expend fuel in driving off more water than is abso-
lutely necessary, it is always an object with the
manufacturer to obtain a fully saturated brine. This
is done by placing a quantity of rock-salt in the
cistern, into which the brine is pumped, and allowing
the liquor to act upon it until it is saturated. A
strong wooden frame is fixed in the cistern at about
half its depth, upon which the rock—salt is thrown, and
the earthy residuum is occasionally removed from
thence, when all the salt has been dissolved.
In the evidence given before a Select Committee
of the House of Commons in 1836, Mr. Worthington,
a salt manufacturer of Northwich, thus describes the
method of getting to the brine :——-“ We get to the
spring by sinking a shaft down to the brine, which is
probably a large lake over the body of the salt.
There is usually a strong fiagstone over the brine.
In getting down the shaft to the flag, we form an
inner shaft of smaller dimensions in the first one,
and fill the space between the two shafts with a
puddle of clay, so as to keep what we term fresh
water from mixing with that fully saturated body of
brine which we expect to find below the flag. After
that body of puddle has become solid, the flag is
broken, and usually a large supply of brine flows up
the shaft, driving the workmen and their buckets
before it. This supply of brine has hitherto been
exhaustless. When it has been necessary to sink a
shaft in a different place, it has been from the circum-
stance of fresh water breaking through and mixing
with the brine, thereby making it of no' value. The
fresh water being the lightest, remains on thevsurface
(1) Most of the preceding details are derived from Mr. Henry
Holland's “General View of the'Agriculture of Cheshire.”
ISO‘DIUM. ‘
651 I
in. the shaft, and as you pump up one quantity, all
the fresh water in the surrounding ground follows,
and instead of pumping brine, you pump up much
fresh water with it. Fresh water, however, does not
get to the great body of the lake.”
The brine is drawn from the reservoirs into which
it is first pumped, as it is wanted, through wooden
pipes or by troughs, into the evaporating pans, fig.
2007. These are made of wrought iron, and contain
each from 600 to 1,000 superficial feet. Their usual


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————-‘

Fig. 2007. nvarona'rme THE same.
form is that of an oblong square, and their depth
from 12 to 16 inches. There are 3 or 4. fires to
each pan. There is usually a separate paa-lzoase
to each pan. At one end of this pan-house is the
coal-hole, and the chimney at the other end: along
each of the 2 remaining sides is a walk 5 or 6 feet
wide, and between these walks and the sides of
the pan-house, long benches 41 or 5 feet wide are
fixed, on which the salt is placed in conical baskets
to drain, after it has been taken out of the pan.
A wooden or slated roof is placed over the pan-
house, with openings to allow the steam to pass
freely out.
The process of manufacture in the evaporating pan,
varies according to the kind of salt intended to be
produced. The perfect crystallization of the salt can
only take place under favourable circumstances, such
as a freedom from agitation, and the slow and gradual
evaporation of the water, which holds the salt in solu-
tion; and it is principally on the presence or absence
of these causes, that the variation in the appearance
of the manufactured salt depends.
_ To effect the evaporation of the water, heat is
applied in various degrees, according to which the
product is the slovecl or lamp-salt; common sall; the
large grained flaky ; and large graz'aed, or fisaery
salt.
In making the slave/J, or lamp-salt, the brine is
brought to a boiling heat, or 225° Fahr. Crystals of
salt are soon formed on the surface, but these subside

almost immediately to the bottom of the pan by the
agitation of the brine. If taken out, each crystal
appears at first sight to be granular or a little flaky;
but on closer examination, it is found to approach the
form of a somewhat irregular quadrangular pyramid.
As the evaporation proceeds, similar crystals form
and fall to the bottom. At the end of 12 hours,
the greatest part of the water of the brine has
evaporated; that which remains being only enough
to cover the salt at the bottom of the pan. The fires
are then slackened, and the salt is drawn to the sides
of the pan with iron rakes. The Waller then places
a conical wicker-basket or barrow, as it is called,
within the pan, and having filled this with salt by
means of a small wooden spade, '-
leaves it for a short time to
allow the brine to drain into
the pan, and then carries it to
one of the benches at the side,
where the draining is completed.
It is afterwards dried in stoves,
heated by a continuation of the
same flues which have passed
under the evaporating pan. It
loses, in drying, about one-
seventh of its weight. In
making this salt the pan is
filled twice in the course of
24 hours.
On the first application of heat, if the brine con_
tain any carbonate of lime, the carbonic acid quits
the lime, which is either thrown up to the surface
when the boiling begins, together with the earthy
and feculent contents of the brine, and is removed by
skimmers 5 or it subsides to the bottom of the pan,
along with the salt first formed, and with some portion
of the gypsum, and is raked out in the early part of
the process. These two operations are called clearing
the pan: some of the brines scarcely require them
at all, and others only occasionally. Dr. Henry
found these clearings to consist of, in 480 parts, 384.‘
of chloride of sodium, 20 of carbonate of lime, and 7 6
of sulphate of lime. Circumstances, however, are
continually occurring to vary these proportions even
in the same brine.
In making the common salt, the pan is filled only
once in 24 hours. The brine is first brought to
a boiling heat, as in making stoved salt, with the
double view of bringing it as soon as possible to a
state of saturation, and of more readily clearing it of
its earthy contents. When these objects have been
attained, the fires are slackened, and the crystallization
is carried on, with the brine heated to 160° or 170°
Fahrenheit. The salt formed in this process is in
quadrangular pyramids, or hoppers, close and compact
in texture, frequently clustered together, and larger
or smaller, according to the temperature employed.
Small cubical crystals will often be intermixed with
and attached to these. The remainder of the process
is similar to that for the stoved salt, except that after
draining in the baskets it is immediately carried to
the store-house, and not afterwards exposed to heat.

652
~ SODIUM.
The large grained flaky salt is conducted at a
temperature of 130° 01'1410°.' This salt is somewhat
harder than common salt, and approaches nearer to
the natural form of the crystals of chloride of so-
dium. The pan is filled once in 418 hours. As salt
of this grain is often made by slackening the fires
between Saturday and Monday, and allowing the
crystallization to proceed more slowly on Sunday,
when no work is done, but only a man kept to pre-
vent the fires from going out, the salt has hence
obtained the name of Sunday-salt.
In making the large grained or fishery salt, the
brine is heated to 100° or 110° Fahrenheit, so that
the evaporation of the water and the crystallization
of the salt proceed more slowly than in making the
other kinds; and as no agitation is produced in the
brine at this temperature, the salt forms in large
cubical crystals, seldom, however, quite perfect. At
this temperature, 5 or 6 days are required to evaporate
the brine.
In the course of these several processes, various
additions are, or were formerly, made to the brine,
with the view of promoting the separation of any
earthy mixture, or the more ready crystallization
of the salt. Animal jelly and gluten, blood, white
of egg and glue, have been used. These substances,
being mixed with the brine, coagulate with the heat;
and in this way entangling the insoluble matters of
the brine, gradually rise to the surface, in the form of
a thick scum, which being removed, the brine is left
'clear. In the evidence given:? before the Parliamentary
Committee, in 1835, it was stated that the use of
these substances had long been discontinued.
At the time of Mr. Holland’s Report, in 1810,
'buller or some other oily substance was generally
‘added to the brine during the evaporating process,
and after the clearing, to assist the granulation of the
salt, and to make the brine “ work more kindly.” Its
use is as follows :—During the evaporation, it fre-
quently happens that the small crystals of salt which
form on the surface of the brine adhere together, and
instead of falling to the bottom of the pan, form a
kind of crust over a considerable-portion of the surface
of the brine, thus impeding the evaporation, and, by
confining the steam, causing the brine beneath to
acquire too high a temperature. When a crust of
this kind forms, the salt-boilers say, that “the pan is
set over.” It is somewhat raised above the surface
of the brine, and is usually of an opaque white colour.
Now if a very small portion of butter be added to the
brine in one of the largest pans, it may be seen in a
very few minutes to diffuse itself over the whole
surface, and in its progress to occasion any crust
which may have been formed on the brine to subside
to the bottom of the pan. At the same time a
quantity of steam is observed to rise; the super-
:abundant heat is carried 0E, and the crystallization
afterwards proceedswith regularity. Salt-boilers have
also been in the habit of adding alum to their brine,
when they wish to procure a hard firm salt, of large
"grain. I
But whatever method is adopted. to separate the

impurities of the brine from the salt, they cannot all
be removed from the pan. A portion of these subside
to the bottom, and form an incrustation, which the
workmen call para-Scratch, or scale; which, gradually
accumulating together with a portion of salt mixed
with them, it becomes necessary to remove from
the pan every 3 or 4: weeks, by pie/ring, that is, by
heavy blows with sharp iron picks. Dr. Henry found
in 480 parts of these pickings {t0 of chloride of
sodium, 60 of carbonate of lime, and 380 of sulphate
of lime. These proportions, however, are subject to
variations in different brines. The pan-scratch accu—
mulates most towards the close of the evaporation;
for when there is much salt deposited in the pan, it
forms such a heavy mass at the bottom, that the
water cannot penetrate into it; and hence the portion
which is lowest undergoes a sort of calcination and
fusion, which gives it extreme hardness, and a very
strong adhesion to the pan.
It was long supposed that British salt was inferior,
as a preserver of animal food, to the salt procured
from France, Spain, Portugal, and other warm climates,
where it is prepared by the spontaneous evaporation
of sea-water. Hence large sums of money have been
paid every year to foreign nations, for the supply of
an article which Great Britain possesses, beyond
almost any other country in Europe, the means of
drawing from her own internal resources. Some
years ago, Dr. Henry instituted a careful inquiry into
the subject, feeling how important it was to ascertain
whether this preference of foreign salt was founded
on accurate experience, or was merely a matter of
prejudice; and in the former case, whether any
chemical difference could be discovered to explain the
superiority of the one to the other.
The result of Dr. Henry’s inquiry was, that the
slight differences in chemical composition discovered
by him in the numerous specimens of salt which he
analysed, were scarcely sufficient to account for those
properties which are imputed to them, on the ground
of experience. The stored and fishery salt, for
example, though differing in a very trivial degree as
to the kind or proportions of their ingredients, are
adapted to widely different uses. Thus the large-
grained salt is peculiarly fitted for the packing of fish
‘and other provisions, a purpose to which the small-
grained salts are much less suitable. Their different
powers, then, of preserving food, must depend on
some mechanical property; and the only obvious one
is the size of the crystals and their degree of com-
pactness and hardness. Quickness of solution, it is
well known, is nearly proportional, all other circum-
stances being equal to the quantity of surface ex-
posed. And since the surfaces of cubes are as the
‘squares of their sides, it should follow that a salt
whose crystals are of a given magnitude, will dissolve
four times more slowly than one whose cubes are
only half the size.
That kind of salt, then, which possesses ,most
eminently the combined properties of hardness, com-
pactness, and perfection of crystals, will be best
adapted to the purpose of packing fish and other
somrnvr.
353
provisions, because it will remain permanently between
the difierent layers, or will be very graduallydissolved
by the fluids that exude from the provisions; thus
furnishing a slow but constant-supply of‘ saturated
brine. On the other hand, for the purpose of pre—
paring the pickle, or of stat/ring the meat, which is done
by immersion in a saturated solution of salt, the
smaller-grained varieties answer equally well’; or, on
account of their greater solubility, even better.
The specific gravity of various specimens of salt,
which is probably connected with the mechanical
property of .hardness and compactness of crystals, is
almost the same in the large-grained British salt as
in that of foreign manufacture. “ If no superiority,
then, be claimed for British salt, as applicable to
economical purposes, on account of the greater degree
of chemical purity which unquestionably belongs to
it, it may safely, I believe, he asserted that the larger
grained varieties are, as to their mechanical properties,
fully equal to the foreign bay-salt. And the period,
it may be hoped, is not far distant, when a prejudice
(for such, from the result of the investigation, it
seems to be) will be done away, which has long
proved injurious to the interests and prosperity of an
important branch of British manufacture.” ‘
The most extensive and productive deposits of
rock-salt in Europe are those of Bochnia and Vieliczka
in Galicia. Numerous other deposits are found along
each side of the great Carpathian range, and may be
said to extend with greater or less intervals all the
way from Moldavia to Suabia. This very extensive
tract comprehends the salt mines of Wallachia, Tran-
sylvania, Galicia, Upper Hungary, Upper Austria,
Styria, Salzberg, and finally of Tyrol. Such deposits
form a distinct member in the series of stratified
rocks, occurring with limestone, clay, chalk, gypsum,
stinkstone, slate, and not unfrequently with bitumi-
nous formations. Some geologists suppose that rock-
salt has been deposited from saline lakes, or even by
the sea, which once covered and afterwards quitted
the place. Dr. Macculloch remarks on this hypothe—
sis: “ The purity and'solidity of the masses of rock-
salt, their _bulk, their insulated and peculiar positions,
with many other facts on which I need not now
enter, prove that they could not have been derived
from the ocean in the manner thus supposed, nor
probably in any manner. They are special and
original deposits, in whatever way produced; as of the
design we cannot doubt, though no other ends should
have been in view than the uses of this substance to
man.”
The deposits of salt among rocks of almost all ages
is an interesting and important fact. Salt is daily
accumulating in certain inland lakes and marshes; in
Poland it probably exists principally, if not entirely,
among tertiary rocks; in the Austrian Alps it is
placed in the oolitic system; in Switzerland it is
referred to the has ; in Wirtemberg it is in the
muschelkalk; in England our greatest salt mines are
in the new red sandstone, but there are 2 or 3

(1) Dr. Henry’s Analysis of several varieties of British and
Foreign Salt—Philosophical Transactions, vol. 0.

copious salt springs in ‘the coal formation, from one
of which salt has been largely extracted. In certain
parts of the United States salt springs issue from old
transition slate rocks; and lastly, a spring containing
a great proportion of salt rises near Keswick from
the lowest division of the slate rocks of Cumberland?
When a spring during its course comes in contact
with a bed of rock~salt, anatural brine well is formed,
asalready noticed. These wells are seldom so highly
saturated as the artificial springs formed by letting
fresh water down through a bore to the middle of the
salt-bed, and pumping it up again as a saturated
solution. Natural salt-wells are usually very slightly
impregnated, or they have become weakened by
mingling with fresh water after leaving the salt-bed;
yet, in many inland situations, where the cost of car-
riage would make salt a yery expensive article, it is
found profitable to boil down the weak brine of these
springs for the purpose of obtaining salt. In such
cases, however, an abundant supply of . cheap fuel
must be at hand; and even then it would be too
costly to conduct the process entirely by means of
artificial heat. The greater portion of the water is,
therefore, first removed by evaporation in the open
air, and the smaller portion of the water is got rid of
by boiling.
- Now, as the rate at which evaporation proceeds
depends upon the amount of surface exposed to the
open air, an ingenious contrivance is resérted to in
Savoy and Germany, by which the weak brine is
exposed to the air in the form of rain, and the action
of the air is increased by retarding the single drops
as they fall. This plan was first introduced at
Moutiers, the capital of the province of Tarentaise,
in Sardinia, in the year 1550, for the purpose of
obtaining a more economical supply of salt from the
neighbouring brine springs of Salins. The plan was
first described in England by Mr. Bakewellf’ from
whose account the following particulars are derived.
The salt works at Moutiers are conducted with
remarkable economy, and produce nearly three million
pounds of salt from a source of water which would
scarcely be noticed except for medicinal purposes in
any other country. The springs that supply the salt
works rise at the bottom of a nearly perpendicular
rock of limestone, situated on the south side of a deep
valley or gorge, through which the Doron runs before
it joins the Isere. The distance from the springs to
the salt works is about a mile; the water runs in an
open canal made for the purpose, but is received in a
reservoir in its passage, where it deposits part of its
ochreous contents, and the canal along which it runs
is also lined with a red ochreous incrustation. The
water rises from the rock with considerable force,
and emits much gas, which is principally carbonic,
with a mixture of sulphuretted hydrogen; it has an
acidulous and slightly saline taste. These springs
rise at the end of long passages, excavated in the
rock. The temperature of the strongest spring is
99° Fahra: it contains only 1.83 per cent. of saline

(2) Sedgwick and Murchison; Geol. Trans. 1835.
(3) Travels in the Tarentaise. 1823.
0541
SODIUM.
matter; other sources contain only 150. Besides
common salt, the water contains small proportions of
sulphate of lime, sulphate of soda, and sulphate and
muriate of magnesia, together with oxide of iron.
It may seem remarkable that these waters, which
have only half the strength of sea-water, should repay
the expense of evaporation. It is obvious that water
so weakly impregnated with salt as to contain only
one pound and a half in every 13 gallons, could
not repay the expense of evaporating by fuel in any
country. In order to make salt from this saline
water, it was necessary to concentrate it by natural
evaporation, and to effect this speedily it was-required
to spread the surface of the fluid over as large a
space as possible, the rate of evaporation being in
proportion to the extent of surface exposed to the
action of the atmosphere. The first attempt at
Moutiers was made in 1550, by arranging pyramids
of rye-straw in open galleries, and letting the water
trickle through them gradually and repeatedly. By
this process a portion of the sulphate of lime was
deposited on the straw, and the water became con-
centrated to a certain degree. It was then carried
to the boiler and further evaporated by fuel. In
1730, the present buildings were erected. There are
four evaporating houses called Zlfaz'soas d’Jlpz'aes or
them-leases. Nos. 1 and 2 receive the water from
the reservoir, and concentrate it to about 3° of
strength, that is, they evaporate one—half of the
water they receive. These houses of evaporation
are each 350 yards in length, about 25 feet in
height, and 7 feet wide. They are uncovered at
the top. They consist of a. frame of wood composed
of upright posts, 212- feet from each other, ranging on
each side, and strengthened by bars across: the
whole is supported on stone buttresses about 3 feet
from the ground, under which are the troughs for
the salt water to fall into. The frame is filled with
double rows of fagots of blackthorn, ranged from one
end to the other up to the top : they are placed loosely
so as to admit the air, and supported firmly in their
position by transverse pieces of wood. In the middle
of each Maison d’Epz'izes is a stone building containing
the hydraulic machine for pumping the water to the
top of the building; it is moved by awater-wheel.
When the water is raised to the top it is received in
channels on each side, which extend the whole length
of the building; from these long channels it is made
to pass into smaller ones by the side, from which it
trickles through a multitude of small holes, like a
very gentle shower upon the fagots, where it is di—
vided into an infinite number of drops falling from
one point to another. Being thus exposed to the
contact of the air, it gains one degree of strength in
falling, and by the action of the pumps it is raised
again, and falls in other showers, till it has acquired
the strength adapted to its passing to the evaporating
house No.‘ 2.1
The process is conducted with less nicety in Nos.

(1) Mr. Bakewell remarks that this mode of evaporation by the
use of fagots was long misunderstood; that it has often been
stated by English writers and has recently been again gravely

I and 2 than in the others. The pumps are dis-
tributed at equal distances on each side of the thorn
wall, and are worked by the machine in the centre of
the building. The water is not allowed to trickle
down on both sides of the thorns, but only on that
exposed to the wind. The two buildings, Nos. 1 and
2, are placed at different angles, to catch the different
currents of wind that rush down the valley. No. 3 is
constructed on the same principles as Nos. 1 and 2;
it receives the water from them both; it is 870 yards
long, and is covered to preserve the salt water from
the rain. There are 12 pumps on each side of this
buildings. and more care is taken to distribute the
water equally: here it is concentrated to the strength
of 12 per cent, and deposits most of its remaining
sulphate of lime in incrustations on the twigs.
The water being now reduced to about one-seventh
of the original quantity, is passed along channels to
the thorn-house No. a. This is only '70 yards’ in
length; here it is further concentrated by a similar
process till it nearly reaches the point of saturation,
but this depends on the season. In dry weather it is
raised to 22°, but in rainy moist weather to 18° only.
In summer time, the whole process of evaporation in
passing through the different houses, is about one
month; in wet seasons it is longer. The stream of
water that sets in motion the hydraulic machines for
raising the saline water to the top of the building, is
brought by a small aqueduct from the river Doron.
When once in motion the process goes on and
requires little further attention or manual labour till
it is completed. When the water is nearly saturated
it passes to a large building containing the pans for
boiling, and the salt is crystallized in the usual
method. The following statement will convey an idea
of the quantity of water evaporated before it comes
to the pans :—
8,000 hogsheads when received at the evaporating
houses, Nos. 1 and 2, contain about 1%; per cent. of
salt, and are reduced by evaporation to 43,000 hogs-
heads.
d,000 hogsheads when received at No. 3 contain
about 3 per cent. of salt, and are reduced to 1,000
hogsheads.
1,000 hogsheads when received at No. 4 contain
about. 12 per cent. of salt, and are reduced to 550
hogsheads.
550 hogsheads received at the pans contain nearly
22 per cent. of salt.
Thus, out of every 8,000 hogsheads passing through
the evaporating houses, 7,450 are evaporated by the
air in summer, and about ‘7,000 in winter; and only
one—sixteenth part of the fuel is consumed that would
be required for evaporating the whole quantity of
water by fire.
The fagots are changed at periods of from 41 to
'7 years. Those in Nos. 1 and 2, where the saline
impregnation is weak, will decay sooner than in Nos.

repeated that it consists in throwing salt water upon burning
fagots, and gathering the salt that remained. This would be a
mode of making salt as wise and practicable as the nursery method
of catching birds by putting salt on their tails.
SODIUM.~ _
655
3 and 41. In No. 3 all the twigs acquire so thick a
coating of sulphate of lime, that, when broken off,
they resemble stems and branches of encrinites.
In the covered house, No. 3, there are 2%
pumps—~12 on each side—to distribute the water
more equally over the whole. This system of
pumps is worked by joined bars of wood, which move
backwards and forwards, and are connected by crank
wheels with each piston to raise and depress it. It
has been already mentioned, that care is taken to
evaporate on the windward side of the building.
When Mr. Bakewell was on the top of No. 3, though
the air was very warm, he felt an intense degree of
cold, in consequence of the speedy evaporation.
The total length of the Maisoas d’Epz'aes is as
follows :—
Nos. 1 and 2 together 700 English yards.
No. 3 . . . 370 ,, ,,
NO. ‘1- . . . . . 70 n 1:
Total 1,140, or nearly two-thirds of a mile.
The fuel used at the pans for the last process is
partly wood and partly anthracite, from the neigh—
bouring mountains. The anthracite answers remark-
ably well when once ignited, as it preserves, for a
long time, a regular degree of heat. The consumption
of wood was formerly so great, that it has stripped
many of the higher mountains in the Tarantaise, and
exposed them to the action of the
atmosphere, which has occasioned
vast éloalemeals, or mountain slips;
for it is found that forests are of
the greatest utility in preserving
mountains from destruction. The
fact is now so well ascertained, that
the Government, for this cause alone,
have paid particular attention to the
preservation of the wood. The
quantity of salt made annually at
Moutiers is estimated at about 2,250,0001bs, andabout187,0001bs. :v
of sulphate of soda. The other
alkaline matter which adheres to
the pans is sold to the glass-makers.
The Government receives on the
average 150,000 francs for the pro- _
ducts, out of which it is estimated
that 30,000 are expended for wood
and fuel, 8,000 for materials employed in the build-
ings, and for the fagots, &c., and 62,000 for the
wages of the different officers; leaving an annual
profit of 50,000 francs.
Brine springs are met with at a few places in
Saxony; but as they are only slightly impregnated
with salt, evaporation by means of fuel would be far
too costly a method of obtaining this necessary article
of food from them. The method of graduation
adopted at Moutiers was introduced into Saxony in
the year 1559; and as the plan has, from time to
time, received the attention of scientific chemists, it
has, in many respects, been improved. We may,
therefore, be allowed to introduce a few more details
on this interesting subject.


.Fz'g. 2009.

At the Saxon salt-works, the’ brine‘ is pumped up
into a large reservoir, generally placed in a tower,
.from which it flows into the troughs of the thorn—
house. A number of horizontal pipes convey the
brine from these troughs 6 ll, Fig. 2009, in a thin stream
to a perforated channel 0, from which it falls, drop
by ch'op, upon the wall of blackthorn fagots l. A
sloping board prevents the wind which passes through
the thorns from giving a wrong direction-to the
falling drops, and the whole is covered with a roof 7',
to prevent rain-water from mingling with the brine.1
That the air may exert its full effect, the whole
structure is erected in an airy situation, and in a
direction at right angles to that of the prevailing
wind. If the wind changes, and threatens to carry
the brine away from the wall, the graduation is re-
versed to the opposite surface of the thorn-wall, and
this is done by moving a lever, whereby certain
channels are closed, and others opened, and the brine
is carried to the other side, to the opposite surface
of the thorns. The brine thus slowly falling and
trickling through the thorns, exposes a large surface
to a constant current of air, which thus carries off in
vapour a considerable portion of the pure water, and
leaves the brine, which falls into the lower tank,
much stronger than before. The operation is re-
peated from 3 to 8 times, for which purpose the

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“Til ‘ _;~.\‘~\; \?‘-\ - 1 _ __ "
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’ __.\
'rnonn ‘WALLS non Evarona'rme BRINE-
graduation houses are divided into several compart-
ments, the foremost of which serves for the first fall,
the second for the next fall, and so on. At Schene-
beck, the surface of the thorn-wall is equal to 390,000
square feet, and this evaporates on an average during
the day 3-1-76ths cubic feet of water from each square
foot of wall; or in a year of 258 working days,
nearly a million and a quarter hogsheads of water.
The pumps which serve to raise the brine are
usually situated in the central part of the works,
and are commonly worked by a hydraulic wheel, as at
Moutiers.
Previous to the introduction of this plan into
Saxony, the graduation was effected by distributing

(1) In the engraving, the greater portion of the roof is removed.
656
SODIUM.
the brine over fiat inclined wooden surfaces,.or over
ropes, stretched backwards and forwards in lengths
of many thousand feet. This method is still in use ,at
Moutiers, in addition to the plan already noticed;
and during the whole summer, salt was formerly crys-
tallized solely by graduation, without any evaporation
by fire. The Maison cle Carries, or rope-lioase, ‘was
invented by an ingenious Savoyard, named Buttel.
It is 440 yards in length, and'11 wide: it is much
stronger than the Maison ol’lijoines, the roof being
supported by 6 arches‘of stone-work; the interme-
diate spaces on the sides being left open. In every
one of these divisions are 1,200 cords in rows of 24
each, suspended from the- roof, and fixed tight at the
bottom. The cords are about 16 feet in length. The
water is raised to a reservoir at the top of the build-
ing, and distributed in a number of small transverse
canals, each row of 241 cords having one of these
canals over it, which is so pierced as to admit the
water to trickle down each separate cord drop by
drop. The original intention of this building was to
crystallize the salt itself upon the cords; for which
purpose the water was made use of from the pans,
after it had deposited a quantity of salt in the first
boiling, to save the expense of fuel in a second boil-
ing;—the residue-water of the first boiling, by re-
peatedly passing over the cords, deposited all its salt
in about 45 days, and the cords were incrusted with
a cylinder of pure salt, which was broken off by an
instrument adapted to the purpose. This process is
at present abandoned for crystallizing; but the cords
are still used for evaporating, and are found to answer
better for the higher concentration of the water than
the fagots. This method did not answer for the first
evaporation, because the water rotted the cords; but
it was discovered, that the cords were not, soon in-
jured by it when it had acquired 5° of strength. Mr.
Bakewell was informed that the cords at Moutiers
had many of them remained 30 years in use without
being changed; indeed they were so thickly incased
with depositions of gypsum as to be defended from
the action of the water. This mode of evaporating
is found to be more expeditious than that of the
fagots.
In the Maison ole Carries it is found that the evapo-
ration goes on more speedily in windy weather than
in the liaisons el ’Epines, as might be expected from
the more ready access of air to the surface of the
water. The cords are double, passing over horizontal
rods of wood at the top and the bottom, to keep
them firm in their positions, and at regular distances
from each other. The cords are not thicker than the
finger, but with the incrustations‘of sulphate of lime
they are often as thick as the wrist.
But to return to the Saxon method of graduation
by the use of thorn-walls. Of course the graduation
proceeds best with a moderately warm wind and sun-
shine; a moist calm atmosphere is less favourable to
it, and in rainy weather the process is- suspended.
Very strong? winds also occasion inconvenience, by
carrying ofi the'brine. ‘Frost is also injurious; for
'Berzelius has ‘observed, that below 27° Fab. sulphate

of magnesia, with a portion of chloride oi sodium, be
comes converted into chloride of magnesium and
Glauber’s salt; and that this decomposition is not
reversed when the weather becomes warmer. Salt is
therefore not only lost in this manner, but the quan—
tity of chloride of magnesium is increased, which is
injurious in the boiling process. - Graduation is there-
fore limited to the most favourable portion of the
year, including about from 200 to 260 days. It is
necessary to regulate the flow of the brine according
to the force of the wind; but even with this pre-
caution, there is always considerable loss, from the
blowing away of the smaller drops, and also from salt
evaporating with the water. That a portion of the
salt does evaporate with the water has been proved at
the salt-works of Nauheim, where the director, "\1.
Wilhelmi, placed .a plate of glass upon a tall pole be
tween two evaporating houses, distant about 1,200
paces from each other, and it was foundin the morn-
ing, after the drying of the dew, that the glass was
covered with crystals of salt on one or the other side,
according to the direction of the wind.1
In the course of time, the thorns over which the
brine trickles become covered with a thick coating
of thorn-stone, as it is called, consisting of carbonates
of lime, magnesia, manganese, and iron, with traces
of chlorides. -As these deposits gradually fill up the
interstices of the thorn-wall, and stop the draught of
air, it is necessary to renew the wall every 5, 6, or
8 years. In the brine-cisterns a similar deposit forms
like a fine mud, sometimes accompanied by a greyish,
thick, scum-like mass, filled with bubbles ; this is
almost entirely composed of living infusoria, evolving
large quantities of pure oxygen.
The progressive evaporation of the water, although
varying with the nature of the locality and the state
of the weather, may be seen from the following state-
ment, which refers to Diirrenberg.
One cubic foot of brine contains—-
In'the beginning 2'5 lbs. of salt.
After the first graduation ....... .. 3'9 ,,
After the second 5'6 ,,
thiIdQOQOnnQQQs00|-.'.-.uu~|a 8. ,,
100 lbs. of salt are therefore dissolved—
In the beginning in 38'3 cubic feet of water.
After the first graduation ....... .. ,, 24-7 ,, ,,
After the second ,, 16~6 ,, ,,
After the third ,, 11'3 ,, ,,
For every 100 lbs. of salt are therefore evaporated—-
In thefirst graduation............... 13'6 cubic feet.
In the second........................... 8'1 ,,
In the third 5-3 ,,
As the evaporation diminishes the loss in graduation
increases with the strength of the brine, and, at
length, a period arrives when the loss of salt by the
wind is equal to the advantage of further evaporation
of water. The brine is generally considered fit for
boiling when it contains 23 per cent. of salt. If the

(1) Pallas remarked, so long ago as 1770, that in the neighbour-
hood of’ the salt lakes of Asiatic Russia, the dew was salt to the
taste, and not only the dew which was deposited on plants, but
that which collected on smooth surfaces, and even on the dress of
persons exposed to it. See the German edition of his Travels,
vol. i. p. 426, and v01. p. 635.. ' '
l
SODIUM.
657
natural spring contains as much as this, as is the
case in some places, the brine is boiled down at once
without being graduated.
The brine which is graduated during the fine
season, is stored up in vast reservoirs of masonry,
covered over and protected from frost. Here the
brine makes a further deposit of matters suspended
in it. From these reservoirs the pans in the boil-
ing-houses are supplied. The boiling is carried
on during the winter months only. Each pair in
which the boiler is conducted is a flat four-sided
vessel of sheet iron, with a flat bottom, somewhat
deepened towards the middle. Some of these pans
are as much as 60 feet in length, and 30 in
width.
The bottom is supported by brick-work, which
contains the fines, which are arranged so as to dis-
tribute the flame of two separate fires as uniformly
as possible; the fines are also made to heat the
chambers where the salt is dried. In order that evapo-
ration may proceed rapidly in the pans, it is necessary
for the air to circulate freely above the surface of
the liquid.‘ For this purpose each pan is covered
with a roof-shaped hood of boards, into which de-
scends a steam or vapour trunk, furnished at the
bottom with a number of wooden shutters, which
can be turned back or closed as occasion may require.
The external air thus passes in a constant current
over the surface of the brine, and becoming satu-
rated with vapour, escapes into the chimney. As
this vapour contains about one per cent. of salt,
means are taken for collecting that portion of it,
which becomes condensed, and trickles down the sides
of the chimney. This is done by placing, near the
bottom of the chimney, a sort of channel connected
with a tube leading into a tank. The process of
boiling consists of two distinct operations: first, the
safilotay/e, or the further purification and evaporation
of the brine, up to the point of saturation; secondly,
the soccage, or crystallization of the salt.
The pans are rather more than half filled with
clear brine from the reservoirs, and raised rapidly
to the boiling point, the portion which escapes as
vapour being replaced from time to time by fresh
brine. The surface soon becomes covered with a
dirty brown scum, which, with various salts, forms a
thick mud. This is partially removed by means of
rakes, but a quantity collects on the bottom of the
pans, forming what is called pan-scale. After 12
or 15 boilings it increases often to the thickness
of an inch, and must then be broken up with chisels
before it can be removed. The salts in the deposit
are chiefly gypsum and sulphate of soda, with a
quantity of chloride of sodium ,- so that these deposits
occasion a loss of salt during the boiling.
In the mean time, the solution of salt becomes
more concentrated by the constant evaporation and
renewal of the brine, until, at last, it crystallizes. A
pan containing 1,600 cubic feet of brine, or 176 cwt.
of salt, being refilled as often as %th of the quantity
is evaporated, the quantity of salt in the pan after
the first addition will be
VOL II.

17 6 . .
1'76 + T = 221 lbs. ; after the second addition
176
176 + 2 T = 286 lbs. and so on. When, there-
fore, at the end of 20 or 24.1 hours, a pellicle of
crystals begins to form over the surface, the fire is
diminished until the temperature of the brine is al—
lowed to fall to 1941 O Fahr. and from that to 167°,
when, with slow evaporation, the soccage begins and
lasts for several days, during which time the small
floating crystals on the surface gradually form into
four-sided funnels, and soon sink to the bottom by
the agitation caused by the escaping vapour. When
the pan is kept at a high temperature the crystals
have no time to increase in size, and salt of a finer
grain falls to the bottom. At the lowest possible
temperature they remain floating a longer time, and
produce salt of coarse grain. In the former case
the process is rapid, in the latter more slow. But
neither the process nor the temperature of the soc-
cage are entirely at the command of the workmen,
because the chloride of magnesium is always a source
of obstruction when little or no sulphate of soda is
present. Then two salts mutually decompose each
other in the pan, giving rise to chloride of sodium
and sulphate of magnesia.
It was observed with the brine from Rodenberg,
that the more concentrated brine which contained
chloride of magnesium, but no sulphate of soda,
became constantly covered all over its surface, at the
ordinary temperature of soccage, with a continuous
scum of salt which the vapours could neither break
up nor pass through, and when removed it was imme—
diately formed again, and thus prevented evaporation
from going on. Thus no coarse-grained salt could be
produced, and the evil could only be remedied by
reducing the temperature, which occasioned loss of
time. A remedy was found for the evil by mixing
the weaker brine, which contains sulphate of soda but
not chloride of magnesium, with the former; but the
mixture thus produced contains these two salts, which
mutually decompose each other, and produce chloride
of sodium and sulphate of magnesia. The result was
the same when sulphate of soda was added at once,
without diluting the brine by adding the salt in solu-
tion. During Sunday, when all work is stopped,
Sunday—salt is produced by large crystals forming at
the bottom; for the salt not being quite so soluble in
cold as in hot brine, a portion begins to crystallize as
soon as the temperature is lowered, and this attaches
itself to the other crystals already in the pan.
The purity of the salt gradually diminishes towards
the end of the process. Thus Berthier found in the
salt of Moutiers :-—-
Sulphate
Chloride of 02* Sulphate
Salt. Magnesium. Gypsum. Magnesia. of S Ma.
At the beginning... 94'64 -- 1'56 — 3'80
In the middle ..... .. 93-59 0'61 -— 0 25 5'55
Towards the end... 85'5 2'0 -- 12'5 ._
For ,tbis reason the soccage must be stopped before
all the salt is deposited.
During the whole process of soccage, the salt is
U U
658
.SODIUM.
raked up from the bottom with long rakes to the
edge :of the pan, and placed either in wicker baskets
of peeled willow, or heaped upon boards, which are
thrown back for the purpose; and in either case, the
brine which drains from the salt is allowed to flow
back into the pan.
conveyed to the drying-room, either in the same
willow baskets, or it is spread out upon hurdles, and
allowed to remain ‘so long as it loses moisture. It is
then packed up for sale.
The salt thus produced is never entirely pure
chloride of sodium. It is frequently contaminated
with ;a minute portion of one or other of the following
salts-~z—Ghloride of magnesium, chloride of calcium,
sulphate of soda, (Glauber’s salts,) sulphate of mag-
nesia, (Epsom salts,) sulphate of‘ lime (gypsum). Of
all these salts, the chloride of magnesium has the
greatest influence on the quality of the produce, on
account of its deliquescence in the air, and its highly
saline taste. Pure chloride of sodium never attracts
‘moisture from the air; but, when containing only a
minute portion of chloride of magnesium, it soon
becomes wet in damp weather. Such salt, however,
is usually preferred to the purer kinds in places where
salt is expensive; because, on account of its v‘pungent
taste, a much smaller quantity is consumed. The
chloride of magnesium can be got rid of during the
soccage by adding slacked lime to the brine in the
pan.
After each soccage a quantity of‘impure brine is
left in the pan, which, however, is not rejected after
every process. A second, and sometimes a. third
charge is boiled down before the residue (the mot/zer-
Zz'gzmr) is removed. This is a viscous, odoriferous
fluid, and may contain the chlorides of calcium, mag-
nesium, potassium, and sodium; the sulphates of
magnesia and of lime, and a trace of bromides and
iodides. Epsom and Glauber’s salts are extensively
manufactured from this source, which also furnishes
a supply of pure bromine and iodine.1
It is an interesting fact, that the plants which gene-
rally grow on the sea-shore, such as the tr‘z‘gloc/zz'num
marz'zfz'mum, the salicor'm'a, the salsola ,taZz', the aster
z‘mfolz'um, or Farewell-to-summer, glam: maritime, &c.,
occur also in the neighbourhood of salt-mines vand
salt—springs. And the reason for this is, that in such
situations they find the food adapted to their habits.
“ It. is thought very remarkable,” says Liebig, “that
the plants of the grass-tribe fitted for the food of
man follow him like the domestic animals. But
saline plants seek the sea-shore or saline springs, and
the chenopodium the dung-hill, from similar causes.
Saline plants require common salt, and the plants
growing only on dung-hills need ammonia and nitrates,
and they are attracted to places where these can be
found, just as the dung-fly is to animal excrements.
So, likewise,'none of our corn-plants can bear perfect‘
seeds;- that is, seeds yielding flower, without a large
7 supply of phosphate of magnesia and ammonia, sub—

(1) For many of the foregoing particulars respecting the manu-
facture of salt in Germany we are indebted to Knapp’s Technology,
vol. i. translated by Dr. H-onalds, &c.
The moist salt which remains is"

stances which they require for their maturity. And
hence, these plants grow only in a soil where these
three constituents are found combined, and no soils are
richer in them than those where men and animals
dwell together : where the manure furnished by these is
found, corn plants appear, because their seeds cannot
attain maturity unless supplied with the constituents
found in such manure. When we find sea plants
near our salt works, several hundred miles distant
from the sea, we know that their seeds have been
carried there in a very natural manner, namely, by
wind or by birds, which have spread them over the
whole surface of the earth, although they grow only
in those places in which they_ find the conditions
essential to their life. ,
“ Numerous small fish, of not more than 2 inches
in length (Gasterosterzs aculeazfus), are found in the
salt-pans of the graduating house at Nidda, a village
in Hesse Darmstadt. No living animal is found
in the salt-pans of Neuheim, situated about 18
miles from Nidda, but the water there contains so
much carbonic acid and lime, that the walls of the
graduating house are covered with stalactites. Hence
the eggs conveyed to this place, by whatever cause,
do not find the conditions necessary for their de-
velopment, although they did so in the former
place.” _. '
The waters of the ocean afford a convenient means
for obtaining a supply of common salt to persons
situated on or near the coast. The saline matter of
sea-water varies from 3 to a per cent., and of this
quantity, common salt forms nearly two-thirds. The
specific gravity of sea-water varies from about 1'026
to 1030, pure water being 1000. Many years ago
Dr. Marcet made a number of analyses of the water
of different-seas, and his general conclusions were as
follow:-—l. That the Southern Ocean contains more
salt than the Northern, in the ratio of 1'02919 to
102757. 2. That the mean specific gravity of sea-
water near the equator is 102777, or intermediate
between that of the northern and that of the southern
hemispheres. 3. That there is no notable difference
in sea-water under different meridians. a. That there
is no satisfactory evidence that the sea at great depths
is more salt than'at the surface. 5. That the sea in
general contains ,more salt where it is deepest and
most remote from landkand that its saltness is always
diminished in the vicinity of‘ large masses of ice.
6. That small inland seas, though communicating
with the ocean, are much less salt than the ocean.
,7. That the Mediterranean contains rather larger
proportions of salt than the ocean.
The water of the Mediterranean contains in 1,000
parts, according to the analysis of M. Laurens—-
Grains.
. . 959‘06
Chloride of Sodium, (common salt) ........... .. 27 '22
Chloride of Magnesium.............................. 6'14
Sulphate of Magnesia, (Epsom-Sa1t)............ 7'02
Sulphate of Lime, (Gypsum) 0'15
Carbonate of ” 0'09
Carbonate of Magnesia.............. 0'11
Carbonic Acid 0'20
" 3- a‘...
Potash 0'01 _
SODIUM.
659
There was also a trace of iodine, and of extractive
matter.
It may be interesting to compare this analysis with
that of the water of the English Channel near
Brighton. Dr.’ Schweitzer found in 1,000 grams of
seawater——
Grains.
964-74372
Chloride of Sodium.......................... 27'05948
Chloride of Magnesium 3‘66658
Chloride of Potassium...................... 0'76552
Bromide of Magnesium..................... 0'02929
Sulphate of lVIagnesia............................ 2'29578
Sulphate of Lime.................. 1'40662
Carbonate of Lime............. 003301
The specific gravity of the water was 10274, and
it was the same when taken from the bottom of the
sea, 10 fathoms deep. The quantity of iodine was
very minute; 17‘llbs. troy not containing one grain
of it. Dr. Schweitzer remarks, that when these
analyses are compared, the Channel water will be
found to contain 9 times as much lime as the
Mediterranean, which is to be accounted for by its
flowing over a bed of chalk.
Since the date of these analyses, Dr. George
Wilson, of Edinburgh, has discovered that flaorz'ae is
an element of sea-water. He was led to search for
it after observing that fluoride of calcium is slightly
soluble in water, which explains its occurrence in
springs and rivers. The specimens of sea-water first
examined, were taken from the Frith of Forth.
Dr. 'Wilson says, “I obtained the mother-liquor or
bittern from the pans of a salt-work there, and pre-
cipitated it by nitrate of baryta. The precipitate,
after being washed and dried, was warmed with oil of
vitriol, in a lead basin covered with waxed glass, with
designs on it. The latter were etched in 2 hours,
as deeply as they could have
been by fluor-spar treated in


Subsequent experiments -_
have abundantly confirmed '
Dr. Wilson’s observations.
tecting fluorine in the hard
crust which collects at the
bottom and sides of the
boilers used in the evapora- =4“
tion of sea-water at the salt-
works. Dr. Forchammer
has found in sea-water mi—
nute quantities of manga-
nese, ammonia, baryta, or
strontia, besides iron and
silica.1
At one of the meetings of the British Association,
Professor Forchammer read a paper, in which he
endeavoured to show that in the ocean between
Europe and America, the greatest quantity of saline

(1) See Dr. Wilson’s paper in the Transactions of the Royal
Society of Edinburgh, 1846, 8zc., and in the Edinburgh New
Philosophical Journal, 1850, &c.

matter is found in the tropical region, far from any
land. In such places 1,000 parts of sea-water con-
tain 366 parts of solid matter. This quantity
diminishes in approaching the coast, on account of
the masses of fresh-water which the rivers throw
into the sea; it diminishes likewise in the western-
most part of the Gulf stream, where it was found
to be only 35'9 in 1,000 parts. By the evaporation
of the water of this warm current its quantity of
saline matter increases towards the east, and reaches,
in N. lat. 39° 39' and Wqlong. 55° 16’, its former
height of 365. From thence it decreases slowly
towards the north-east, and sea—water at a distance
of 60 to 80 miles from the western shores of
England contains only 35'? parts of solid substances;
and the same quantity of salt is found all over the
north-eastern part of the Atlantic, as far to the north
as Iceland, always at such a distance from the land
that the influence of fresh-water is avoided. From
numerous observations made on the shores of Iceland
and the Faroe Islands, it is evident that the water of
the Gulf stream spreads over this part of the Atlantic
Ocean, and thus we see that water of tropical currents
maintains its character even in high northern lati-
tudes.
The water of the different seas is much more
uniform in its composition than is generally be-
lieved. The greatest quantity of solid matter ever
obtained by the Professor was 371 in 1,000 parts,
and this was from water near Malta.
It will be seen from the preceding analyses of sea-
water, that the quantity of pure water necessary to
be evaporated in order to obtain the solid salt, is
enormous. The method, however, usually adopted is
so economical, that the salt can be sold at a very low










\\
. \-
... "* ..‘\\\-\\ .\
J M“ \\
‘ .___ ._.,.- neg-AN»
‘ ‘3&5.
\
. \
‘T: .
—_\
price. The sea-water is exposed in a series of shallow
ponds to the action of the sun and air, by which
means the water is evaporated and the salt deposited
in the hindermost pools, whilst the foremost ones are
constantly supplied with fresh sea-water. This opera-
tion is carried on in what are called salt gardens or
salleras, which are laid out upon a clay soil, on the
sea-coast ; they are secured from the influence of the
u u 2
660
SODIUM.
. mud.
tides, and are worked during the summer months,
from about March to September.- The collecting pond
A, Fig. 2010, is filled at the flow of the tide through
a flood-gate to the height of from 2 to 6 feet.
Here the evaporation begins, but the principal object
of this first pond is to allow the water to deposit its
The clear water is then conveyed by means of
a pipe w from the collecting pond to the front poolB,
which is quite horizontal, but very shallow. This pool
13 '13 is divided into a series of canals by means of a
central embankment, and arms proceeding alternately
from it, and the sides of the pool. The salt-water
meanders slowly from one canal to another in the
direction of the arrows, until having arrived at o, it
passes along a pipe into a channel which runs along
the 4: sides of the saltern, which in that from which
the diagram is taken is 10,000 feet long. Having
reached D it enters the ponds E. E, following the
direction of the arrows, and then passing through an
open channel it reaches a third series of ponds Fr.
From I? r the brine passes by means of the channels
it it into the crystallizing ponds e G, where the
evaporation is completed. The ponds G e are filled
by means of channels at the corners, which can be
stopped up at pleasure with a wooden plug. When
the brine is admitted into the crystallizing ponds, it
is sufficiently concentrated by evaporation during its
long transit, to be on the point ‘of depositing its
salt. When ready to do so, a reddish tint usually
appears in the brine. The salt crystallizes on the
surface of the water, and the crust is broken up and
collected with rakes into small heaps z' 2' on the sides,
and from these the mother liquor runs off, and is
collected by appropriate channels, and when’ no more
salt separates by crystallization, the lye is allowed to
run 0E through K into the sea. ‘The salt, as‘ at first
collected, is too impure for use, the chief impurity
consisting of chloride of magnesium: the smaller
heaps z‘ z‘ are therefore made up into larger square or
round heaps J J, which are allowed to remain for a
time covered with straw. The rain is thus kept oil’,
and the moisture of the atmosphere suffices to liquefy
the chloride of magnesium, which is thus gradually
separated from the saline mass.
Although the entire surface of the saltern amounts,
together, to many hundred acres, yet the process
depends so entirely upon the sun and wind, that in
wet weather the evaporation sometimes entirely
ceases. At the commencement of the season, 8 days
may be required for‘ the deposit of salt in the crystal-
lizing ponds ; but in fine weather, and when the brine
is properly evaporated before’ arriving at these ponds,
salt is collected 2 or 3 times a-week, and in some
cases every day.1
Salterns were formerly not uncommon on the coast
of Great Britain, and they continued in active opera-
tion “until the repeal of the duty on salt enabled the
Cheshire manufacturers to sell the article at so very
lowja price, that the proprietors of many salterns could
not compete with them. It may however be interest-

(1) Dumas: Chimie appliquée aux Arts, tom. 11.;
Technology, vol. i. '
Knapp’s
ing to notice the method of manufacture formerly
adopted at Lymington in Hampshire, as it differs in
some respects from the continental plan above de-
scribed. The sea-water was concentrated, by spon-
taneous evaporation in the saltern, to about lgth
of its bulk, and it was then admitted to the boilers.
One kind of salt was chiefly prepared there, which
most nearly resembled in grain the stoved salt of
Cheshire, and the process for obtaining it varied in
some respects from that already described. The salt
was not fished out of the boiler and drained in
baskets, but the water was entirely evaporated, and
the whole mass of salt taken out at once every 8
hours, and removed into troughs with holes in the
bottom. Through these it drained into pits made
under ground, which received the bittern or mother
liquor. Under the troughs, and in a line with the
holes, were fixed upright stakes, on which a portion
of salt, that would otherwise have escaped, crystal;
lized and formed, in the course of 10 or 12 days
on each stake, a mass of 60 or 80 pounds. These
lumps were called salt cat's. They bore the propor-
tion to the common salt, made from the same brine,
of 1 ton to 100,
From the mother liquor in the pits, sulphate of
magnesia (Epsom salts) was manufactured during the
winter season, when the manufacture of salt was sus-
pended. The process was simple. The bitter liquor
from the pits was boiled for some hours in the pans
which were used in summer to prepare common salt,
and the impurities which rose to the surface were
removed by skimming. During the evaporation a
portion of common salt separated, and this being
too impure for use, was reserved for the purpose of
concentrating the brine in summer. The evapo-
rated bitter liquor was then removed into wooden
coolers one foot deep, where it remained 24+. hours,
during which time, in clear and cold weather, the
sulphate of magnesia crystallized at the bottom, in
quantity equal to about éth of the boiled liquor.
The uncrystallizable fluid was then let off through
plug-holes at the bottom of the coolers, and the
Epsom salt, after being drained in baskets, was
deposited in the store-house. This formed single
Epsom salts, and after being dissolved and crystal-
lized a second time, it was termed double Epsom salts :
At or 5 tons of sulphate of magnesia were produced
from a quantity of brine that had yielded 100 tons
of common and 1 ton of cat salt.1
The simple process of evaporating sea-water on
the sea-shore, by means of the sun and the air, in
order to obtain a supply of culinary salt, is so obvious
that it need not excite surprise that distant nations
should adopt similar methods in order to arrive at the
same result. Accordingly, we find that salterns are
used in some of the islands of the Eastern Archi-
pelago. Sir Stamford Rattles describes the salt manu-
factories of Java as being important, both with regard
to the comforts of the inhabitants, and the interest of
the revenue. Nearly the whole of the north-east

(1) Dr. Henry: Philosophical Transactions. 1810. "
SODIUM.
661
immediately obtained.
coast of Java and Madura, abounds with places well
adapted to the construction of salterns, and unfit for
any other useful purpose. The process is simple, and
well suited to the people who practiseit. On this
coast the soil is of a clayey nature, and .free from
dark loam, which are necessary qualities to the success
of the process. The salt-water is admitted through
a succession of shallow square compartments, in each
of which it receives a certain degree of concentration,
until arriving at the last, the water is completely
evaporated, and the salt left behind fit for immediate
use. The salt thus obtained, though discoloured by
admixture with foreign ingredients, is remarkablyfree
from those septic, bitter, and deliquescent salts con-
sequent on a more hasty evaporation._ This manu-
facture goes on during the whole of the dry half of
the year. To the success of the operation, it is ne-
cessary that the soil should be clayey to prevent the
water sinking through; that the shore be flat and
extensive, to give easy admission to the brine; and
that high mountains should be at a distance, that the
process may not be rendered diflicult or precarious by
the heavy rains that fall in their neighbourhood. It
is the absence of this combination of favourable cir-
cumstances, that renders the manufacture of salt
impracticable in most of the other countries of the
Archipelago. .
On the boisterous south coast of the island 0
Java, the shelving nature of the shore, and the porous
quality of the soil, will not admit of the cheap process
just described. The natives have recourse to another
“method. The sand on the beach being raked and
smoothed into the appearance of ridges and furrows,
as if intended for cultivation, the manufacturer, having
filled a pair of watering cans from the surge, runs
along the furrow, sprinkling the contents in a shower
upon the ridges. In a few minutes the powerful
efl'ects of the sun’s rays have dried the sand, which
is then scraped together with a kind of hoe, and
‘placed in rude funnels, over which is thrown a given
quantity of salt-water, by which a strong brine is
The peasants convey this
brine to their hovels, where it is boiled in small
quantities over an ordinary fire, and a salt is obtained,
which is necessarily impure, in consequence of the
haste with which the operation is- performed. This
salt costs four-fold as much as the better product of
the north coast.1 It is at the same time inferior in
quality, and is only consumed. in places which the
latter is prevented from reaching by the difficulty of
conveyance, or inland tolls and prohibitions; and it
has consequently been calculated that the north coast
salt, if allowed to pass toll-free through the country,
‘would in a short time supersede that from the south
coast altogether. The inferior quality of the latter
is caused by the quantity of the sulphate of magnesia
it contains, which renders it, by its bitterness, un-
pleasant for culinary purposes.
The Javanese method of obtaining salt from sea-
sand has been practised on the coast of Lower Nor-

1) Crawford : History of the Indian Archipelago.

mandy from the ninth century. The method is the
same in principle, although the practice differs. The
sand is collected on the sea-shore, where it is left dry
by the tide; this is done by means of a long broad
scoop, drawn by a horse; the sand is then formed
into a kind of filter, through which sea-water is al—
lowed to percolate; this adds considerably to the
strength of the sea-water, which is then evaporated
in shallow leaden boilers; the fuel is wood; and
during the boiling, the scum which rises to the surface
is removed. The boiler is filled up many times until
a quantity of salt collects in it ; the salt is then kept
in constant motion by means of long rakes, to prevent
the lead from fusing. The evaporation is continued
until the salt is dry. In this state it is very impure,
and is taken out by means of a perforated tool shown,
Fig. 2011, and placed in baskets which are suspended


_Fz'g. 2011.
over the boilers, and the steam which rises from them
in the next operation of' evaporating penetrates the
baskets, and washes out a large portion of the bitter
deliquescent impurities. The salt is then removed to
warehouses, and, with the assistance of the tool shown
in Fig. 2011, piled‘ up on the floor, which is formed
of a close hard cement. Here the salt parts with
another portion of its impurities, and in the course of
two months, loses from 20 to 28 per cent. The salt
is then very fine and pure, and as white as snow.
From 700 to 800 litres of salt-water produce from
150 to 225 kilog. of salt. The lead pans being sub—
jected to this constant heating and cooling, soon
become permanently enlarged in size, and require to
be frequently reset.
In some parts of Asiatic Russia, advantage is taken
of the cold of winter to obtain salt by the congelation
of sea-water. The method is founded upon this re-
markable property—that when brine is exposed to a
temperature some degrees below the freezing point,
it resolves itself into two portions, one consisting of
pure water, which freezes, and can be-iremoved as
solid ice; the other consisting of brine; which does
not freeze, but becomes of course intensely salt by
the removal of the fresh water. The solid salt is
then obtained from the brine by the usual process
of boiling. -
The salt thus obtained is, however, very impure,
unless the precaution is taken beforehand to purify
the brine by means of lime. The effect of the low
temperature is to decompose aportion of the common
salt, and to convert the sulphate of magnesia of the
brine into sulphate of soda and chloride of magnesium.
In the salt obtained from the brine separated by
freezing a portion of water from the sea of Okhotsk,
M. Hess found :—
662
SODIUM—SOLDER— SOLDERING.
Common Salt v77-60
Sulphate of .. .. 13,60
Chloride of Aluminum .. 6'20
Chloride of Calcium 0‘94
Chloride of Magnesium 1'66
100'00

M. Hess attributes the scorbutic diseases which
are so common in the ‘places where this salt is used,
to the presence of these chlorides. M. Dumas re-
marks that this is the first analysis of bay-salt in
which chloride of aluminum has been found.
It will be seen from the foregoing details that the
collection and preparation of common salt form an
important branch of manufacture in different parts of
the world. We have noticed the various methods of
procuring salt: viz. 1. by mining for rock salt; 2. by
pumping up the brine from brine wells, and evapo-
rating it by artificial heat, so as to produce, under
certain conditions of temperature, the marketable‘
varieties. known as stoved or lamp-salt, common salt,
large-grainedfla/ry salt, Sunday salt, large-grained or
fislzerg/ salt, &c. 3. Evaporating the brine by the
process of graduation, as in the thorn-walls, &c., where
the brine is weak, and fuel scarce. ‘4;. Evaporating
the brine by means of solar heat, as in salterns. 5.
Saturating the brine by means of sea-sand. 6. Con-
centrating the brine by the action of a low tempes-
rature. Other methods of forming or collecting salt,
together with a great variety of particulars respecting
the mineral, are given in a work written by the Editor,
and quoted below, and to which we are indebted for
most of the information to which it refers.‘
The principal portion of the Cheshire salt, both fossil
and manufactured, is sent down the River Weaver to
Liverpool for distribution and exportation; only a
small proportion being conveyed to other places by
canal and land carriage. The white salt made from
the Staffordshire springs is chiefly exported from Hull;
while that from Worcestershire vfinds an outlet at
Gloucester. In the year 18414:, 13,417 6,884: bushels
of rock and white salt were exported, of which
quantity——
Russia took . 1,823,756 bushels.
Denmark 462,576 ,,
Prussia 1,686,520 ,,
Holland on.Dunno-0'03‘!Oioqouicooop-up‘o‘Iota.‘ 799,802 H
Belgium . 1,041,028 ,,
Sweden and Norway 237,594 ,,
Germany 301,426 ,,
British North American Colonies 1,772,799 ,,
United States of America 4,664,430 ,,
Western Coast of Africa 374,452 ,,
New South Wales 125,801 ,,
Guernsey, Jersey, &c. 41,032 ,,
The remaining quantity was sent in small shipments
to the West Indies, ports in the Mediterranean, Brazil,
&c. The quantity retained for home consumption in
the same year is estimated at 12,6417,616 bushels.2

(l) “Tlie Natural History of Common Salt: its manufacture,
appearance, uses and dangers in various parts of the world.”
Published (1850) under the direction of the Committee of General
Literature and Education, appointed by the Society for Promoting
Christian Knowledge.
' (2) Porter: Progress of the Nation.

The quantity of salt exported from Great Britain
and Ireland in the year 1849 amounted, to 18,539,865
bushels, of the declared value of £252,991. Of this
quantity, Russia took 2,216,308 bushels, Prussia,
1,231,860; Holland, 9411,1803 Belgium, 693,537 ;
France, 263,772 ; Western Coast of Africa, 411,473;
British India, 1,195,935 ; British North America,
2,388,768; United States of America, 7 $06,524;
Australia, 143,317.
In 1851, salt was exported of the declared value of
£22a,501; and in 1852, of the value of £236,276.
SOLDER—SOLDERING. Soldering is the art
of uniting the edges or surfaces of metals by partial
fusion, or by the insertion of an alloy, called solder,
which is more fusible than the metals to be united.
Solders are distinguished as lzard and soft. Hard
solders fuse only at a red heat; soft solders fuse at
comparatively low temperatures. The metals and 'the
solders ‘which unite them should agree as nearly as
possible in hardness and malleability; when this‘ is
the case, as when spelter solder is used to unite two
pieces of brass or of copper, or one. piece of each, or
when lead or pewter is united with soft solder, the
work may be bent and rolled almost as freely as if it
had not been soldered. But when copper or brass
are united by soft solder the joint is very liable to be
fractured by accidental violence, or the blow of a
hammer. In applying the solder, it is of importance
that the edges to be united should be chemically
clean, and as in this state they have a strong aifinity
for oxygen, they are protected from the air by means
of some flux, which also tends to reduce any portion
of oxide left on the parts of the metal to be united.
The usual fluxes are borax, sal-ammoniac, chloride of
zinc, common resin, Venice turpentine, tallow, and
sweet oil.
The hard solders in common use are the spelter
solders and the silver solders. The composition of
spelter solders is given under BRASS; they are used for
joining iron, copper, brass, gun-metal, German silver,
&c. The lzardest silver solder is composed of 4.1 parts
fine silver and 1 part copper; this is difficult of fusion.
Hard silver solder is composed of 3 parts sterling
silver and 1 part brass wire, which is added when the
silver is fused in order that the zinc of the brass may
not be burnt out. Soft silver solder consists of 2
parts fine silver and 1 part brass wire: % part arsenic
is sometimes added at the last moment, to make the
solder whiter and more fusible; it makes it, however,
more brittle, and it is objectionable on account of its
very poisonous fumes, which must on no account he
inhaled. Silver solders are laminated and used for all
silver works, and for common gold work, for German
silver, gilding metal, iron, steel, brass, gun-metal, &c.
when a neater effect is required than is produced by
spelter solder.
stitute for silver solder in making gilt buttons, and
hence called also button solder, and still used for the
white alloys called batten metals, is composed of
10 lbs. tin, 6 lbs. copper, and dlbs. brass. The copper ‘
and brass are first melted together, the tin is added,
and the whole stirred and poured through birch twigs
W/zite solder, used as a cheap sub— _
SQLDER—SOLDERING.
663
into water, in order to granulate it; when dry and
cold it is pulverized with an iron pestle and mortar.
Another button solder consists of 10 parts copper,
8 of brass, and 12 of spelter or zinc. The use of
zinc in hard solders is to increase their fusibility; and
in cases where the solder cannot be seen, its presence
indicates the completion of the process, for when the
selder is fused, the zinc becomes volatile, and burns
with a characteristic blue flame, while the remaining
alloy becomes tougher from the loss of the zinc.
Among the hard solders may also be mentioned
fime golrl, laminated and cut into shreds, and used as
the solder for joining the parts of chemical apparatus
made of platinum. Silver is also used as a solder for
German silver. Copper in shreds is used for iron, and
laminated gold solders are used for gold alloys. The
hard solders are also drawn into wires, and filed into
dust to suit the magnitude and circumstances of the
work. a
The soft solder most frequently used consists of
2 parts tin and 1 part lead. A cheaper solder is
formed by increasing the proportion of lead; 1% tin
to 1 lead is the most fusible solder, unless bismuth
be added. The following table gives the composition
of some of these alloys, with their points of fusion :—
No. 1 Tin
25 Lead 558° Fahr,
7’ ,, Illnl|‘00l
.. 541
,, 482
,, 441
,, 37o
,, 334
,, e40
,, 356
,, 365
,, 378
381
b—li—lh-IHHU-l
Nh-I
‘- *0‘.
'0 ..~.
U!
‘
~.
,, 1 Bismuth .......... .. 320
,, 310
,, 292
254
,, 236
,, 202
t—li—li—li—Ilh—ll—ll—IH
T‘P‘E":PS'°E°E"F>S°F°T‘?°P":°~P°E°T‘
Uxv—lr-Imoauikcucntpww
‘M
M‘
WNHNOOQr-dHHHp-ao-ih-Mcp
QoLQh-lu-lr-l
If 8 parts mercury be added to No. 18, the alloy
will melt at 122° Fahr. and may be used for stopping
teeth, and for anatomical injections. No. 5 is the
Plumber’s sealed solder, which is assayed after the
manner of pewter, [see PEWTERJ and then stamped
by an officer of the Plumber’s Company. It is cast in
iron moulds into triangular ingots, from 1 to 6 square
inches in the section. The fine tin solder is cast into
the form of cakes, about 4% inches by 6, and A}; to %, inch
thick. Both this and the more fusible solders are
trailed from the ladle upon an iron plate or a flat
stone into the form of ‘ bars, ribands, and threads.
The alloy No. 8 is used for soldering cast-iron and
steel; the flux used is sal ammoniac, or common
resin. The same alloy is also used for tinned iron,
with chloride of zinc or resin for a flux. Gold and
silver are soldered with pure tin, or with the solder
No. 8, and Venice turpentine as a flux. Copper and
many of its alloys, such as brass, gilding metal, gun-
metal, 850. is also soldered with No. 8, with sal-
ammoniac, chloride of zinc, or resin, as a flux ; also
zinc, with chloride of zinc as a flux. For ordinary

plumber’s work the alloys from A to 8 are used with
tallow as, a flux. For lead and tin pipes the alloy
No. 8 is used with a mixture of resin and sweet oil
as a flux. For Britannia metal, No. 8 is used with
chloride of zinc or resin as a flux.
The modes of applying heat to the works to be
soldered are very various. For hard soldered works
the forge may be used. Coppersmiths, silversmiths,
and others, use a hearth similar to the blacksmith’s,
but standing further away from the wall, to allow of
the soldering of the central parts of large objects, the
bellows being worked by the foot. For large and
long works the brazier’s hearth is a flat plate of iron,
about 4: feet by 3, standing in the middle of the shop
upon 4c legs; the fuel is contained in a central aper-
ture, 5 or 6 inches deep, andabout 2 feet by 1 foot in
area, while the surface of the plate supports tubes
and long works over the fire. In some cases the fire
extends the whole length of the hearth, or 2 separate
fires may be used. A revolving fan is commonly
used for the blast, which is directed into the fire by
means of tuyeres. A hood is suspended by counter-
poise weights from the ceiling, so as to be raised or
lowered as required, and it is furnished with sliding
tubes for conveying the smoke to the chimney. ' In
some cases mutfles or iron tubes are placed in the fire,
and in these the articles to be soldered are heated.
The best fuel for soldering is charcoal; nextto this
coke or cinders ; coal is injurious on account of its
sulphur.
The blow-pipe is also largely used in soldering;
but the mechanic commonly uses it in a much rougher
manner than the chemist, who excites an intense heat
by means of a pencil of flame drawn out silently by
air from the mouth, and capable of fusing, oxidizing,
or deoxidizing the object of analysis. [See BLOWPIPE]
The mechanic employs a much larger flame than the
chemist, such as that from a lamp wick, %; inch to an
inch in diameter; the blowpipe also has a larger
aperture’, it is blown strongly, and held a short dis—
tance from the flame, so as to spread out a wing of
fire with a roaring noise, although in certain cases,
as in jeweller’s work, where a small portion is to be
heated, a point of flame is produced. '
The blowpipe flame, as obtained by the blast of
bellows with the enameller’s lamp, is noticed under
ENAMELLING. The manufacturers of cheap jewellery
at Birmingham, have a contrivance, represented in


Fig. 2012.
Fig. 2012, in which a stream of air from bellows
directs a gasflame along a trough or shoot, placed
664:
SOLDERwSOLDEItlN G.
at a small angle below the flame. The support is a
disk of sheet iron 3 or 41 inches in diameter, mounted
on a wooden handle, and covered with a matting of
binding wire from ‘~3- to ainch thick, fastened to the
disk by bending some of the wires round the edge.
The work to be soldered is placed upon the wire, or
upon small cinders supported by the wire, and the
flame is thus passed over the work.
In the operation of brazing, or soldering with a
fusible Mass, the joints are first secured in their pro-
per position by means of binding wire, the ends of
which are twisted together with pliers: the granu-
lated spelter and pounded borax are. mixed in amp
with a small quantity of water, and spread along the
joint with a small spoon or a slip of sheet—metal. The
work is then placed above the clear fire, so as gra-
dually to evaporate the moisture, and fuse the borax,
which parts with its water of crystallization, froths
up, and then gradually becomes limpid: the solder
melts at a bright red heat, as indicated by a slight
blue flame from the zinc. The work is then some-
times tapped, to assist the flow of the solder through
the joint, but the solder usually flashes, or is absorbed
by the‘ joint: as soon (as this is done the work must
be removed from the fire, and when the solder is set
the work may be cooled in water. In soldering works
in iron, a coating of loam is used to prevent the iron
from scaling off. For common works, such as locks,
and in soldering the spiral wires which form the in-
ternal screw within the boxes of ordinary tail-vices,
strips of sheet-brass are used as the solder; and in the
last example, as soon as the solder has fused, the box
is rolled to and fro on the ground, in order to distri-
bute it equally. The finer works in iron, steel, and
brass, are soldered with silver solder, which combines
readily with the various metals without wasting the
edges of the joints, or, as the workmen term it, with-
out gnawing them or eating them away. Although
this solder is expensive, yet, from the neatness of
effect, and the small amount of finishing required, it
is really an economical solder. This solder is lami-
nated, cut up into small squares with shears, and put
on the joint with forceps. The borax is in many cases
previously boiled or fused in its water of crystalliza-
tion, in order that it may not froth up on the work
and displace the solder;- or the borax may be fused
upon the joint itself before the solder is put on.
Mathematical and drawing instruments, buttons,
jewellery, &c., are supported on charcoal, and sol-
dered with the blow-pipe. The dentists, in soldering
the gold work to which artificial teeth are attached,
use a lump of pumice-stone as a support, which has
the advantage of retaining its form while a charcoal
support burnsaway.
The methods of soft-soldering are various, as may
be seen by the variety of fluxes used. The joints of
lead-works are first defined by smearing around them
a mixture of .size and lamp black, named soil : this
prevents the ‘solder from adhering to the parts not
intended for its reception. The joints are scraped
clean with a'triangular disc of steel riveted on a wire
stem, and called a stave-71007:, and the clean metal is
rubbed over with tallow. In some cases the joints
are wz'perl, that is, the solder is heated somewhat be-
yond its point of fusion, and poured upon the joint in
suflicient quantity to heat it: the solder is then
smoothed with a cloth made of several folds of thick
bed-ticking well greased, and with this the super-
fluous solder is wiped off. In other cases the joints
are striped, or left in ridges from the bulbous end of
the plumber’s crooked soldering-iron, heated nearly
to redness, and used with the cloth for heating the
F joint and moulding the solder. For slighter, and
neater works, such as lattices, the soldering is per-
formed with the assistance of the copper-bit or bolt,
two forms of which are shown inFigs. 2013, 2014,
and consisting of a piece of copper, of from 3 or 41
ounces to as many pounds, riveted into iron shanks,


Figs. 2013, 2014.
and fitted with wooden handles. For works in tinned
iron, sheet-zinc, and many of those in copper and other
thin metals, this tool, called a soldering-iron, is used
for melting the solder. For this purpose it is tinned
by raising it to a dull-red heat, filing it clean, rubbing
it on a lump of sal-ammoniac, and then pn a copper
or tin plate containing a little solder, which, if these
operations be quickly done, so as not to cool the tool
below a certain point, will adhere to the iron, and
make it ready for use. When the edges of the work
have been brought together they are strewed with
powdered rosin, the soldering-iron is held in the right-
hand, the cake of solder in the left, and the two are
rubbed together, so as to melt a few drops of solder at
intervals along the joint. The iron is then applied so
as to heat the edges of the joint and to fuse and dis-
tribute the solder. The parts are held together by a
broad chisel-formed tool, or by a hatchet stake, or
the joints may be tacked together at distant intervals
by a drop or two of solder; but in many cases the
parts are kept together by the hands alone. The tool
should be passed once slowly along the work, being
guided by the edge or fold of the metal, so as to pro-
duce a fine and regular line of solder. Two soldering—
irons are generally employed, in order that one may be
in the fire while the other is in use. The iron must
be made hot enough to raise the edges to the fusing
point of the solder, but not so hot as to burn off its
own tin coating, or render the solder too fluid. If
not over-heated, the iron can be used for picking up
a bit of solder from the tray in which the cake is. fixed
in an upright position, and thus a drop of solder can
be applied exactly where it is wanted.
The great use of fluxes being to protect the metal
from oxidation, to which it is so liable at high tem-
peratures, the choice of the flux is not veryimportant,
so that it fulfils this object. It is, however, usual. to

employ powdered sal-ammoniac with copper works
SOLDER—SOLDERING.
665
and those in sheet—iron: rosin and sal-ammoniac are
sometimes mixed; and in other cases the edges of the
work are moistened with a saturated solution of sal-
ammoniac by means of the stubby end of a piece of
cane, resin being afterwards used. Chloride of zinc,
formed by dissolving zinc in muriatic acid, is an era
cellent flux, and is well adapted to zinc, which is more
difficult to solder than other metals.
The soldering-iron cannot be used when the pieces
to be joined are tolerably thick, as in parts of philo-
sophical apparatus, gas—fittings, &c. The parts, being
filed or turned, are separately tinned by being dipped
into melted solder covered with powdered sal—ammo-
niac: the work is thus tinned before it has time to
become heated. The surfaces, if large, may be tinned
by moistening them with the solution of salammoniac,
or they may be dusted with the dry powder, or with
resin, then heated on a clear fire until a strip of
solder, held against them, fuses and adheres. ‘When
the parts are properly tinned, they are raised to a
heat a little above that required for melting the solder:
solder is then applied and properly distributed, and
the parts being rubbed together the work is left to
cool under pressure.
Small works may‘sometimes be united by moisten-
ing the cleaned surfaces with sal-ammoniac water, or
by the application of resin, and then placing between
them a slip of tin-foil cleaned with emery-paper: on
pinching the whole together between a pair of heated I
tongs, the foil will melt. The blow—pipe is also used
in many cases of soft-soldering. The gas-fitters use
the blow-pipe in joining tin and lead pipes: they do
not employ the spigot-muZ-faueet joint with a bulb of
solder round it, but cut off the ends of the pipes with
a saw, and file the surfaces intended to meet in butt
joints, in mitres, or in T-formed joints, as required.
They use a rich tin solder, with oil and resin mixed
in equal parts as the flux. Mr. Holtzapffel remarks,
that the work looks more like carpentry than solder-
ing.‘ The gas-fitters and pewterers employ a portable-
tore/z, made of 3 or 4: dozen rushes, with only a slight
coating of tallow, and retained in a paper-sheath. The
pewterers have a kind of blow-pipe or hot-air blast,
consisting of a common cast-iron pot lr, Fig. 2015,
with a close cover, containing ignited charcoal, and
termed a fwd .- it
W has a nozzle 5
leading into it,
which supplies
air from bellows
worked by the
I. foot, and another
nozzle 72, which
directs the cur-
rent of hot air
upon the article to be soldered. This is placed upon
a support 9, called a gentleman, which admits of being
adjusted to the required height by a side-screw. The
strip of solder is dipped into oil and applied to the
joint with the righthand, while the work is slowly


Fig. 2015.

(1) In the first volume of the “ Mechanical Manipulation ” is an
excellent chapter on “Soldering.”

turned round with the left. ‘ The solders used by
pewterers are termed laurel-pale, sqfl-pale, and middling-
pale. The first corresponds with No. 8, in the list
of solders. The soft—pale contains 2 parts tin, l of
lead, and 1 of bismuth.
For certain works a method of soldering, termed
autogeazous, and also burning together, has been in-
troduced, in which neither solder norflux is used, the
intermediate metal being identical with that whose
edges are to be joined. The objections to solder in
many cases are that it contracts and expands under the
influence of heat differently from the metals which it
unites, and thus is liable to produce a leaky joint. It
is also more readily attacked by acid and corrosive
substances; and in consequence of the formation of
voltaic currents it oxidizes more easily. Hence in the
leaden chambers and vessels used in the manufacture
of sulphuric acid, autogenous soldering is of import—
ance. Pewter is also in some cases burned together
at the external angles, in order that no difference
of colour may exist. Brass is also burned together,
as noticed under CASTING and-Founnme; and indeed
the method of burning is used for most of the metals
and alloys in making small additions to old castings,
and in repairing holes and defects in new ones.
In the practice of autogenous soldering, the airc-
iiy/clrogen Zzlowpz'pe invented by the Count de Richemont
is useful. It is a contrivance for a jet of mixed hydro-
gen and atmospheric air, which on being ignited pro-
duces a considerable heat. The hydrogen is supplied
by a reservoir E, Fig. 2016, which is filled with shreds
of zinc through an opening at the top, and is then
closed .by the screw stopple s. Sulphuric acid
diluted with 6 times its bulk of water is poured into
the upper vessel v, through a hole It in the centre of






.r/Q
'- Fig. 2016.

a diaphragm placed a little below the cover 0; and
when the acid solution just covers the plate below the
hole [6, a sufficient quantity has been poured in to
charge H without risk of overflow. From the bottom
of this vessel a tube t, passes to the bottom of the
vessel H: this tube is closed at its upper extremity
by a stopple at 12, attached to a wire extending through
the diaphragon. On pulling up this stopple a portion
of the acid solution descends into n, and expels the
air from it through the stopcock and chamber 0, and
along the jet pipe jj, the stopcocks e and j having been
left open for the purpose. These stopcocks being
closed, hydrogen gas accumulates in H, and by its
666
SOLDER—SOLDERINCir—SOLUTION.
pressure forces a portion of the acid solution up the
tube a‘, and back into v, and thus suspends or greatly
diminishes the generation of gas. When the hydrogen
is required for use the stopcock c is opened, and the
gas passing through the siphon—tube bubbles through
water W in which the lower end of the siphon-tube is
immersed, and thus escapes into the safety box, into
which one end of the jet tube j is inserted. The use
of this safety box is to prevent the return of the flame
into H, inwhich case, if air were left in H mingled
with the hydrogen, an explosion might ensue. The
safety box is supplied with water through the
aperture W. After 3 or 4, days’ constant use the
liquid becomes converted into a solution of sulphate
of zinc, which is drawn off through the aperture/z,
which at other times is kept closed with a stopple.
Atmospheric air is supplied to the apparatus by means
of a small pair of double bellows B, worked by the
foot of the operator at z', and compressed by a con-
stant weight w. The air proceeds along the air jet
pipe at, and meeting the hydrogen at the point where
the two pipes unite in an arch, the mixed gases
proceed along the jet pipe f to a jet which is ignited,
held in the hand, and applied to the work. The
various connexions are made by elastic tubes of
varying lengths, so as to allow of perfect freedom of
motion. The gas generator is made of lead, or of
copper washed with lead, and all the exposed parts of
the brass work are washed and united with lead to
protect them from the acid.
In soldering by this method the works are scraped
clean, the hydrogen is ignited, the magnitude of the
flame being regulated by opening the stop-cock j more
or rless; air is then admitted through a, and when the
flame is pointed and well-defined it may be used as a
blowpipe flame, a strip of lead being used instead of
solder, and fluxes seldom employed. In plumber’s
work, to which this method is well adapted, the
weight of lead consumed in making the joints is a
mere fraction of the weight of ordinary solder. More-
over, from the absence of fluxes the, work is more
under the eye; for fluxes, such as resin, often con-
ceal fractures and bad joints,-and the solder often
sticks to the leadwithout being fused into it. More-
over, this method of gas-soldering is less dangerous
than the ordinary method, the plumbers not having to
take their fires upon roofs and among timbers, by
which accidents have occurred, and many a noble
building has been consumed; but the gas generator
may be left on the ground whileithe man ascends to
the roof with the pipe.
The gas flame may also be used for heating the
copper soldering tool, Fig. 2017,‘ and keeping it at
A are!




Fig. 2017.
one temperature, for which purpose the gases are con-
ducted through a tube in the handle, and the flame
plays on the back of the copper bit.1

(I) Richemont’s claim to the invention of autogenous soldering
has been disputed. We are informed that, previously to the year

SOLUTION, an important process in chemical
operations, the objects of which are to prepare sub-
stances for the exertion of chemical action, by sepa—
rating the particles, and destroying the attraction of
aggregation; and, secondly, to separate one substance
from another, by employing such fluids as have a
solvent power over one or more of the substances
present.
Solution is of two kinds: in the one the fluid, or
menstrzmm producing the solution, has no chemical
action on the substance dissolved ; in the other, such
an action does take place. “Water is the great sol-
vent, whose aid is to be first called in: other fluids
are to be resorted to only when that is insufficient.
So general and important is its use, that in speaking
simply of the solubility of a body, water is always un-
derstood to be referred to. All aqueous solutions of
solid bodies are heavier than water; upon this differ»
ence is founded a very convenient indication of so-
lubility, frequently useful, always easy. It is to
suspend a piece of the substance in a glass of undis—
turbed water: if the body be soluble a descending
current will be seen to fall from it, and be visible upon
looking through the water horizontally. If it fall
rapidly, and in dense striae, it will indicate rapid
solubility and the formation of a dense solution; if it
fall in a very narrow stream, it will indicate only
moderate or slight solubility; and by its descending
rapidly, or in a slow broad stream, or by resting about
the substance, a judgment may be made of .the com-
parative density of the solution produced. If no de-
scending current appear, nor any fluid round the sub~
stance of a refractive power or colour different to that
of the water, then the body must be very nearly, if
not quite, insoluble at common temperatures.2
The saliva of the mouth‘ having nearly the same
solubility as water, the taste of a substance may
afford an indication of its solubility; those substances
which are most sapid being, generally speaking, most
soluble.
Water does not dissolve the resins; oils do not
combine with it, and it does not dissolve any one of
the metals. It dissolves the oxides of the metals of the
alkalies, such as potash and soda. Resinous bodies
are soluble in alcohol ; caoutchouc in ether, naphtha,
and turpentine. “If a substance appear to be inso-
luble, or if it be necessary to know whether it be
soluble in alcohol, ether, oils, or any other body, for
the purpose of selecting a solvent from among them,
a portion should be pulverized finely, and introduced
into a small tube, with a little of the fluid to be
tried, and heated. If the substance disappear, it is,
of course, soluble; but if it be supposed to be amixed
body, and partly soluble, though not altogether so,

1833, Mr. Mallet employed an apparatus on the same principle as
Richemont’s, and used it in a similar manner. The late Professor
Danie11,of King's College, also claimed the invention; so did Mr.
London, and also Mr. Thomas Spencer, of Liverpool, whose paper
“ On the theory and practice of soldering metals ” was read before
the Liverpool Polytechnic Society, in May 1840, and published in
the Mechanics’ Magazine, vol. xxxii. -
(2) Faraday, “ Chemical Manipulation,” Sec. vi. In Reg-
nault’s “ Cours de Chimie,” tome , is a valuable article on the
“ Solubility of Salts.” -
' SO OT— SPAIt—STARCI-I.
667
then the presumed solution should be poured from
the tube into an earthenware or platina capsule, and
evaporated carefully and slowly; if any substance
remain, it of course indicates solubility. Trials by
evaporation cannot be made with oil, unless the body
be fixed, and will allow the oil to be burned off; nor
can trials of very volatile bodies be made in this
manner.”
When solution is brought about by chemical action,
the substance is changed in appearance. “A body
not- soluble in water,‘ except by the use of acids or
alkalies, is generally, though not always, rendered so
by chemical action.” The metals are insoluble in any
solvent until they have undergone some change by
its action. Thus, when copper is put into nitric acid
a portion of theacid is decomposed, the copper be-
comes converted into an oxide, which is soluble in
the acid, and thus a salt is formed, viz. nitrate of
‘ copper, or, more properly, nitrate of the oxide of
copper. If it be desired to know whether one
liquid is soluble in another, a portion of the most
valuable is put into a tube, and a small quantity of
the other added to it: the tube is then to be shaken,
and allowed to repose, when it will be seen if the two
have permanently mixed, or whether they separate.
Should they separate, an additional quantity of the
required liquid is to be added, agitated, and observed
as before ; and this process should be continued until
the two liquids form one homogeneous liquid, or the
added portions remain, unmixed. The results will
indicate the degree of solubility. The solution of _
certain gases in water is generally conducted in a
Woulfe’s apparatus, shown in Fig. 717.
The dissolving power of a liquid is, in most cases,
greatly heightened by raising the temperature. Lime
and magnesia are exceptional cases, these bodies being
more soluble in cold than in hot water; and common
salt may perhaps be cited as another exception to the
rule. Sulphate of soda is more soluble in water, at
the temperature of 91-50 Fahn, than at a higher or a
lower point. Gases are also more soluble in cold than
in hot water. A body not soluble at common tem-
peratures, is not made so by the mere application of
heat. Comminution also greatly assists solution.
SOLVENT. See SOLUTION.
SOOT consists chiefly of carbon in a pulverulent
form, condensed from the smoke of wood or coal fuel.
The soot of pitcoal contains sulphate and carbonate
of ammonia, and some bituminous matter.
SORBIC ACID. See MALIG ACID.
SPAR (German Spat/t), a term which, in combina-
tion with specific terms, includes various crystallized
earthy and some metallic substances. Thus, calca-
reous spar is crystallized carbonate of lime; Derby/-
s/n're or fluor spar is fluoride of calcium; heavy spar is
sulphate of barytes.
SPECIFIC GRAVITY, See GRAVITY Srncrr‘rc—
Hrnnosrxrrcs, AND Hrnnonrsanrcs.
SPECIFIC HEAT. See HEAT.
SPECTRUM. See LIGHT—PHOTOGRAPHY.
SPECULUM MIETAL. See CASTING
Eounnrne.
AND
SPELTER. See ZINC.
SPERMACE’I‘I. See WHALE OIL.
SPIKE. See Lavnnnnn.
SPINNING. See CoTToN—ELAx—S‘ILK—Woon
SPIRIT-LEVEL. See LEVEL.
SPIRITS OF WINE. See ALconoL.
SPONGE. See INTRODUCTORY Essex, p. cxxviii.
SPRING. See BALANCE—HOROLOGY—WHEEL-
CARRIAGE—RAILWAY, &c.
STAINED GLASS. See GLASS, Sect. IX.
STAMPED WORKS. See RAISED Wonxs LN
METAL.
' STAMPING MILLS. See METALLURGY.
STARCH is an important element of food, not only
of animals but of vegetables. Liebig says, “ Its
ready convertibility, without change of composition,
into soluble forms, such as dextrine and sugar, adapts
it admirably for carrying on those changes which occur
in the juices of vegetables. It is stored up in the
seeds, roots, and pith of plants, and by its decompo—
sition furnishes the materials for many of the most
essential vegetable products. It also serves as a most
important element of the food of animals, furnishing
not indeed the means of increase of mass, but the
materials for keeping up respiration and supplying
the animal heat. The fats and fixed oils‘ of the vege-
table as well as the animal kingdom, are in all proba—
bility derived principally from the deoxidation of ‘
starch.”
Starch is one of the most abundant constituents
of vegetable principles. It exists in the seeds of all
acotyledonous plants; in many perennial roots which
produce an annual stem ; in tuberous roots; in the
stems of many monocotyledonous plants, as in those
of the palm tribe; in unripe apples and pears, and
also in lichens. It is seldom found in the stems and
branches of dicotyledonous plants. Starch is con-
tained in plants in the cavities of the cellular sub-
stance, not attached to the cell, but surrounded with
an aqueous liquid.
Starch, from whatever source, always presents the
same chemical characters: its physical characters,
however, may slightly vary with the plant which ‘
furnishes it, and the processes followed for obtaining
it. In its pure state it is a fine, white powder, with-
out taste or smell. It emits a peculiar sound when
squeezed between the fingers; it feels- slightly crys-
talline, lous les mole and potato-starch more so than
the other varieties. Starch is not soluble in cold
water, in alcohol or ether. It forms with boiling
water a kind of mucilage which cools down into a
jelly. It is soluble in dilute acids, forming a trans-
parent solution, which undergoes a series of remark-
able changes by boiling [see BEER]. The recent
solution forms a deep blue with an aqueous solution
of iodine; but after boiling for a short time the
colour is purple; and by continuing the boiling, iodine
does not produce any colour, in consequence of the
formation first of dextrine and then of sugar. Starch
forms a transparent gelatinous compound if rubbed.
up in a mortar with a strong solution of potash,
which compound is soluble in water and in alcohol;
668
STARCH.
and the addition of acids produces a precipitation of
the starch. Dried at 212°, starch was found to con-
sist of carbon 4.4.441, hydrogen 6'17’, and oxygen as-
39. At common temperatures starch is represented
by the formula C12H12012: so that by being raised
to the temperature of 212 0, it loses two equivalents
of water. The sp. gr. of ordinary starch is about 1'5.
The usual sources of the starch used in the arts
are 1, wheat and the grains of cereals, which produce
common starciz ; 2, the tubers of the potato, which
furnish potato starch ,- 3, arrow-root, from the roots
of the mar'anta arnndz'nacea ,- 4, East India arrow—root
from the tubers of the carcama angastz'folz'a ; 5, saga,
from the pith of palms of the genus sagas ,- 6, cassava
and tapioca, from the tuberous root of the jatrop/za
nzanz'llot ; 7, Incl-tan corn (zca mats) ,- 8, salcp, probably
from the roots of different species of orchis; 9, Tons
les moz's, probably from canna coccz'nca; and 10, race,
which furnishes m'cc stare/l.
Starch has an organized structure : when examined
by the microscope, it presents the form of rounded
grains, the size and shape of which differ in the
starch of different plants, and also in that of the same
plant at different times, and from different parts of
the same plant at the same time. Thus the diameters
of the granules of potato-starch vary from ,0’, 0th to
the ,%-6th of an inch. The granules of starch from
wheat are more regular in form than those from the
potato. The size of the granules increases with the
age of the vegetable, and in certain organs the shape
also changes. Each granule of starch has an outer
envelope, differing in its characters from the globule
which it encloses; or rather, the granule consists of
concentric layers of unequal thickness. The interior
and exterior are both insoluble in cold water, or so
little soluble that 1,000 parts of water are required
to dissolve one part of starch. On rubbing the
granules in a mortar with sand, the envelope is
broken, and the interior exposed. On putting the
mixed powder into cold water, it swells up into a
tremulous jelly, but does not dissolve more than in
the above very limited proportion. Or if the granules
be not bruised, but be simply mixed with water at

the temperature of 140° Fahn, they imbibe water,
swell, burst their envelopes and form a jelly, which,
however, is not regarded as a solution of starch, any
more than the water sucked up by a sponge is re-
garded as a solution of that substance. If the starch
jelly be placed on filtering paper, ‘it parts with its
moisture’and dries up into a horn-like substance in-
soluble in cold water. This gelatinous starch is
termed ann'rlz'n. It is soluble in boiling water, and a
strong solution, on cooling, will deposit much of the
starch in a gelatinous state. When a solution of
starch is frozen, amidin separates from the water and
contracts into a kind of tissue, which does not dissolve
when the ice is‘ thawed. When starch is boiled in
water, a tegument is formed which dissolves on con-
tinuing .the ebullition: this tegument amounts to
about 3 or 4: parts in 1,000 of the starch.
The granules of some varieties of starch appear
under a high magnifying power to be marked on their

surface with eccentric rings surrounding a well-de-
fined point, as shown insome of the varieties of starch
in Fig. 2018. Raspail regards these wrinkles as
affording indications of a spiral attached _ to the
interior of the tegument, and proceeding from the










~.
m ~.' -.\.
-.,_,4_‘-; ‘L. , .,\ :J'f, ,‘qqgp'q‘k



Rice East India West India
Arrowroot. An'owroot.
[I Q .w
6% I 1,.’ >()% @‘Q'Q e @@%® ' 0 "" Q I
Tapioca. Portland Otabeite
Arrowroot. Arrowroot.
Fig. 2018. MICROSCOPIC nnrnnsnn'rxrrons or mrrnnns'r
VARIETIES or srancn.
point or ln'lmn. M. Fritzsche considers them to
afford evidence of the concentric layers. The hilum
is probably an aperture leading into the interior of
the granule, by which the amylaceous matter which
forms the internal laminae is introduced.
When granules of starch are distended by moisture,
they display the phenomena of double refraction in
consequence of the pressure exerted by the teguments
upon their contents. When put up in Canada balsam
or in water, and viewed in a microscope by polarized
light, a blackjcross is observed (such as is exhibited
under similar circumstances by doubly refracting
crystals) when the planes of polarization of the pola-
mac?‘ and analgscr are at right angles to each other.1

(1) The polarizcr is'a Nicholl’s prism, or a tourmalin placed
beneath the stage on which the object is placed: this polarizes
the light reflected through the object by the. mirror attached to
the microscope. A second Nicholl’s prism orrtourmalin, attached
to the eye-piece of the microscope, forms the analyser. ‘
STARC-I-I.
669
The black cross is shown in some of the varieties of
starch in Fig. 2018. Its centre is at the hilum of the
granule : the other portions of the granule are white,
but the field or ground is black or grey. On turning
round the analyser or the polarizer 90°, the black
cross is replaced by a white one——the other parts of
the granule become dark and the field white. If a
thin plate of mica or of selenite be placed between the
eye and the reflector, the edges of the cross and the
intervening spaces become ' coloured, and the field
assumes a tint'depending on the thickness of the
plate of mica or of selenite. The colours of the ad-
joining spaces on either side of the cross are comple-
menta-ry to each other, and they change on revolving
the analysing plate at every quarter of a revolution.
These beautiful effects are produced by all the varieties
of starch, but with greater or less distinctness, proba-
bly depending on the state of distension. They are
better displayed in tous les mois, potato starch, and
Indian corn starch, than in wheat, barley, and some
other kinds of starch.‘
If starch be dissolved in hot water, and the solu-
tion, when cool, filtered through paper, a precipi-
tate is thrown down by the addition of alcohol; the
structure of the precipitated granules appears under
the microscope to be spherical, and the size of the
granules is less than ,m'moth inch. If starch be heated
for about two hours with from 5 to 15 parts of water,
under pressure to the temperature of 150° cent.
(302° Fahr.) it dissolves entirely, except the outer
coating, and the solution, if nearly boiling, can be fil-
tered through paper. The liquid, on cooling, deposits
a considerable quantity of starch in white granules,
opaque in the mass, and denser than water. When
dry this deposit is white, but without the lustre of
common starch. The increased solubility thus con-
ferred upon starch, is a remarkable fact.
nules are composed of CmHmOw, as in starch dried at
212°.
In the manufacture of starch by the ordinary pro-
cesses, wheat is preferred to any other material. Sir
H. Davy found as much as 7 6'50 per cent. of starch
in a sample of Middlesex wheat; 7 5 per cent. in
Polish wheat; 7 3 per cent. in North American wheat.
Even such wheat as is damaged by exposure or long
keeping will serve for making starch,~——this principle
being much less liable to decomposition than the
other constituents of wheat.
The simplest method of separating the starch from
the gluten and the other constituents of wheat, is by
the process noticed under BREAD, viz. that of washing
dough in a linen bag in a gentle stream of cold water.
By this process, however, the starch is not entirely
free from gluten: a plan is therefore adopted, founded
on the property which dilute acetic acid, or a dilute
alkaline solution, has of dissolving gluten, and not
acting on the starch. The alkali, caustic soda, is spe-
cially added by the manufacturer in making starch
from rice flour; the acetic acid is not added, but is
generated by the fermentation in the liquor, and con-
sequent decomposition of a portion of the gluten and
of the starch. This takes place when wheat is used,

The gra-.

and for the purposes of manufacture the grain is
coarsely ground between iron rollers, and digested in
a vat with water enough to wet it thoroughly. In
3, 41 or 5 days, according to the weather, fermentation
sets in, the mixture settles, and is removed to a large
fermenting vat with more water. There it remains for
2 or 3 weeks, when the deposit is removed to a stout
basket, and washed by a stream of water, with con-
stant stirring. The bran is’ left in the basket, and the
milky liquor which passes through contains the starch;
it is strained through a hair sieve into a square tub or
frame. In about 24. hours the impure starch sub-
sides ; the supernatant liquor is withdrawn by taking
out plugs situated at different heights in the side of
the frame. The deposit consists of an upper layer of
thin, light, mucilaginous matter called the slimes,
below which is awhite coherent layer of impure starch.
The slimes are removed, and the remainder being agi-
tated with fresh water, is thrown upon a finer sieve
than that previously used. When the starch is depo-
sited from the strained liquid, the latter is decanted
off; the second slimes are removed, and the starch is
again agitated with water. Having been again passed
through a sieve it is left for several days, in order that
the deposit of starch may become firm. A little smalt
or artificial ultramarine is added to give the blue tint,
and any trace of acid must be neutralized by the ad-
dition of an alkali. Indeed, it is an advantage to
leave the starch slightly alkaline, since the liability to
fermentation in a damp place generates acetic and
perhaps lactic acid in the starch, the effect of which is.
to weaken the fibres of clothes containing the starch.
When the starch is sufficiently firm, and while still
moist, it is dared, that is, it is shovelled into oblong
wooden boxes 4- to 5 feet long, 1 foot broad, aiid
about 6 or 7 inches deep, perforated at the bottom
and lined with linen cloth or fine canvass. When
tolerably hard the starch is taken out, cut into pieces,
5 or 6 inches square, ‘and set to dry on half-burned
bricks, which by their porosity absorb moisture from
the starch. They are left in this condition for 8 or
10 hours, and then placed in a hot room or stove fitted
with racks for holding the pieces of starch. When
tolerably dry the pieces are removed to a table, and
a slimy crust which forms on the sides is scraped off
with a knife. The remainder, or pure starch, is packed
up in the papers in which it is sold, and strongly
heated in the stove until it becomes quite dry. In
drying it splits up into the prismatic columns which are
well known to the consumers of this domestic article.
Although so clean and beautiful an article is thus
produced, the process of manufacture is really a very
offensive one. The fermentation of the grains pro-
duces a foul acid water called sour water, and the
putrefaction of the azotised substances of the grain
produces a very offensive odour. “The sour water
contains alcohol, acetate of ammonia, acetic and lactic
acids, phosphate of lime, and gluten. The fermenta—
tion which takes place first is the vinous, at the
expense of the sugar and a considerable portion of
the starch; carbonic acid and alcohol are thus formed;
the former is evolved as gas, and the latter remains in
670
STAROH.
the liquor. But when exposed to the air, and in pre-
sence of azotised matter in a state of decomposition,
alcohol does not remain long without undergoing the
acetous fermentation, and it is by the acetic acid thus
formed that the complete separation of the starch
and gluten is effected. The decomposition of a por—
tion of the gluten gives rise to ammonia, which unites
with some of the acetic acid to form acetate of am-
monia. The lactic acid is a secondary product, arising,
from the fermentative decomposition of a portion of~
the starch. It probably assists the acetic acid in dis-
solving the gluten. The loss of a great portion of the
starch and of all the gluten, and the insalubrity of the
volatile products of the fermentation, render the im-
provements of this process highly desirable.” 1 Some
of these inconveniences have been bvercome by falling
back upon the old method of washing dough in water ;
for which purpose a trough is used with an upper
false bottom perforated with numerous small holes;
the dough, made with a very small quantity of water,
is stirred up with a large pestle, while water is poured
on from above. A wooden box below the trough
receives the water containing the starch, and by con-
tinuing the operation long enough the whole of the
starch is separated, and the gluten remains behind in
the trough. The deposit of starch is, however, con-
taminated with gluten and other impurities; these are
separated by fermentation, with one or two washings,
and the starch is dried as before. This method is
said to furnish about 55 per cent. of starch, and
about 30 per cent. of gluten; whereas, the fermen-
tative process previously described gives only 4x5 per
cent. of starch and. no gluten, and it is a great object to
preserve the gluten, for this furnishes the chief mate-
rial for making macaroni, vermicelli, &c. [See MACA—
BONL] Hence the French and Italians, who consume
large quantities of these preparations, adopt that
method of making starch that preserves the gluten.
Wheat is also used in the manufacture in an un-
ground state, for which purpose it is sifted clean, and
soaked in soft water until soft enough to be crushed
between the fingers. It is then immersed for a short
time in warm water, placed in bags, and exposed to
strong pressure in a wooden chest containing water.
The milky liquor thus obtained furnishes starch.
In some starch works the swollen grain is ground
between edge stones, [see Fig. 566,] and the crushed
grain is repeatedly agitated with water in a large
cistern, and thus the starch is separated.
The separation of starch from gluten by the action
of an alkali, was introduced by Mr. Orlando Jones in
184.0. This plan is well adapted to the manufacture of
starch from rice. [See Bron] The alkali used is caustic
potash, or soda, and the solution must contain about
200 grains of real alkali to the gallon. If much
stronger, the starch as well as the gluten would be
dissolved. To 50 gallons of the solution 100 lbs. of
rice are added, and left to macerate for 20 to 241
hours, a vessel of stone ware, of tinned iron, or
tinned copper being used for the purpose. The

(l) Parnell. Applied Chemistry, &c. Second Series. 1844.
I
alkaline solution of gluten is drawn off into a wooden
vessel, by means of a tin syphon, or a tap, in the
bottom of the vessel, the opening for which is covered
with a finely perforated strainer. The rice left in the
vessel is washed with plenty of cold water, which
being drawn off, the rice is put in sieves to drain. It
is then ground to flour, sifted, and ‘again digested in
the alkaline ley, 100 lbs. of flour to 100 gallons of
ley. The deposit formed in the water used in wash-
ing the starch is added to this mixture. The flour is
frequently agitated during 2i hours, and then left to
‘deposit for 70 hours. The fibrous matter of the grain,
with a little starch, is first deposited: and upon this
a layer of starch. The solution, which is of a brownish
yellow colour, and more or less turbid, contains all
the gluten. The starch being deposited, the liquor
is decanted, and the deposit stirred up with abun-
dance of cold water. On being left tranquil for an
hour, the fibrous matter with a little starch is first
deposited, but most of the starch remains suspended.
The liquor is now drawn off by a syphon, passed
through a fine sieve to separate the husk, and is
poured into a wooden cistern. The fibrous sediment
is repeatedly washed until it ceases to yield starch.
The liquor in the cistern is left to settle during about
70 hours ; it is then decanted, and the starch is blued,
drained, and dried as usual.
For inferior rice starches the deposit is not sepa-
rated from the fibrous sediment by decantation, but
the mixture is stirred up, passed through a fine silk
sieve to separate the husk, and received into a wooden
tank, where the final deposit is made. ‘
Starch is obtained from wheat by Mr. Jones’s pro-
cess, by mixing 50 lbs. of wheat meal with 100 gallons
of the caustic alkaline solution, of the strength of
100 grains of real alkali to the gallon, agitating the
mixture repeatedly during 12 hours, and leaving it
for 7 0 hours to subside. The deposit consists of a
layer of bran at the bottom, fibrous matter in the
middle, and an upper layer of starch. The super-
natant liquor is of a brownish yellow colour; it con-
tains the gluten, and traces of other matters. The
deposition being completed, the liquor is decanted,
and the deposit stirred up with fresh water, and
passed through sieves to separate the bran. The
starch is separated from the fibrous matter, as in the
case-of rice starch.
One great advantage of Mr. .Iones’s process is, that
the gluten can be recovered from the alkaline solu-
tion; for which purpose it is carefully neutralized
with sulphuric acid. This precipitates the gluten,
and when it has subsided, the clear supernatant liquor
is decanted, and the precipitate washed, drained,
dried in stoves, and ground into flour. In this state
it is mixed with ordinary flour, used for making bread,
biscuits, &c.
Carbonate of soda is sometimes preferred to caustic
soda, on account of its greater cheapness, as a solvent
for the gluten in the manufacture of rice starch.
Muriatic acid has also been found useful for the same
purpose.
The potato is largely used in making starch, espe-

—'
If"?
'sralton‘.
671
cially in France.l This valuable tuber has frequently
been made the subject of chemical analysis: the fol-
lowing is an analysis by Michaelis of a red potato,
richer in starch than the ordinary varieties, which
usually contain from 5 to 8, or 9 per cent. of starchy
fibrin, and from 9 to 15, or 18 per cent. of starch :—-
Starch and starchy fibrin .. 30'469
Albumen ‘503
Gluten ‘055
Fat ‘056
Asparagin . '063
Extractive matter .. ‘921
Citrates, silicates, and phosphates of potash,
soda, lime, magnesia, alumina, and prob} '8l5
oxides of iron and manganese Chloride of potassium ‘176
Free citric acid ‘047
66'875
100'000

The starchy fibrin, or amylaceous fibrin of the potato,
differs from the fibrous matter of other plants: it
consists mostly of a substance resembling common
starch. Asparagin is awhite, soluble, crystalline sub—
stance, found in the juice of the asparagus. The
shoots of germinating potatos contain a small quan-
tity of solmzz'ne, a very poisonous substance found in
several species of solmzum, such as S. elulcamam, or
deadly nightshade. The tuber itself contains a small
quantity, which is readily removed by the action of
water. Cattle must not be fed on the residue of ger-
minated potatos used in making starch, or their hind
limbs will become paralysed from the action of the
solanine.
The quantity of starch not only differs in the dif—
ferent varieties of potato, but also on the nature of
the soil, the mode of culture, and the season of the
year. Even the same kind of potato yields different
proportions of starch at different seasons. M. Pfaff
found that 240 lbs. of the same kind of potato
yielded
lbs. lbs.
23 to 25
,, September 32 —— 38
,, October 32 -- 40
From November to March 38 -— 45
In as - 28
p, occnououunnvno- ullolunvlulooalunlllioll "'-‘
Starch is not distributed equally over the tuber,
but exists in largest quantity towards the exterior.
In large potatoes the centre is often quite transparent,
containing only cellular tissue and water. Just under
the epidermis is also a thin layer of cellular tissue
without starch: the tissue just beneath this contains
the starch in large quantity, and the proportion gra-
dually decreases towards the centre.
As the manufacturer of potato starch requires to
keep a large quantity of potatoes in store, the best
method of preserving them is a point of great impor—
tance. Potatoes may be kept for ayear or more at the
temperature of freezing water without loss of starch.

(I) In M. Payen’s “ Précis de Chimie Industrielle,” 8vo. Paris,
1851, is a valuable article on Starch, and its manufacture from the
Potato, together with an experimental inquiry into the Potato
Disease. In Dumas’s “ Chimie Appliquée,” 8w. tome vi., is an
excellent chapter on Starch and its manufacture.

It was formerly the practice to keep them in heaps in
underground cellars; but the bruised tubers soon
began to ferment, and the heat occasioned thereby
led to a general fermentation and loss. Potatoes are
now usually imbedded in large shallow ditches, called
silos, dug in a sandy soil, if that be practicable. They
are protected from the air by a thatch, and ventilating
apertures are made by building trunks of wood in
the mass.
In the manufacture of starch from potatoes, the
first process is to soak the tubers in water for about 6
hours, which softens the epidermis, and assists in its
removal. They are then passed through a hopper
into a cylindrical cage, and washed by the revolution
of the cage in a trough of water, while a jet of water
falls on the cage. All the earthy matter and much
of the skin are thus removed. The potatoes are now
passed into a trough, and elevated by means of an
endless chain with buckets attached to a rasping-
machine, where they are passed under a circular rasp,
a common form of which is a wooden drum covered
on its circumference with sheet iron roughened out-
side by punching numerous holes from the inside.
The rasp revolves from 900 to 1,000 times per
minute, and a stream of water plays on its surface to
prevent it from becoming clogged, and to wash off the
pulp to which the potatoes are reduced by its action.
The pulp is conducted into a cylindrical sieve of wire
gauze, formed of 3 pieces of unequal diameters, and
made to revolve by a winch. These cylinders are
supplied with fresh water which, with the starch in
suspension forming a milky liquid, falls into a trough,
while the washed pulp is received in a separate
vessel. A machine used in France in the preparation
of potato-starch is represented in the steel engraving.
The rasp n. is a cylinder furnished on its circumfer—
ence with toothed knives or saws separated from each
other about -._“{--inch, by means of iron plates: the
knives are placed in the direction of the axis of the
drum, and the teeth project from its surface about -i1-._,-th
inch. The rasp rotates on its axis at the rate of
about 800 times per minute. The rasp is contained
in a hopper n, so contrived that, by hanging one of
its sides 8 upon an axis near the top, and keeping the
lower part of the same side pressed in towards the
rasp, this side will yield at the lower part if by acci-
dent any hard body, such as a stone, should get into
, the hopper; but it opposes sufficient resistance when
only the potatoes are between it and the rasp.
While the rasp is in action a stream of water J falls
upon its surface, and thus assists the centrifugal force
of the rasp in clearing its surface of the potato pulp.
The pulp passes down a trough T, and thence to a
series of wire-gauze sieves or strainers, mounted in
fixed frames, one above the other. The pulp is passed
over the first sieve 81, and raised and distributed over
the other sieves, $2 to 86, by means of scrapers at-
tached to an endless articulated chain or band 0 c,
which moves upon rollers c c. There are, of course,
2 of these endless chains, 1 on each side of the sieve
frames, but in the engraving, which represents a ver-
tical section, only one can be shown. The ends of the
672
STARCH.
scrapers are let in to the articulated joints of the
endless chains, and thus this moving system some-
what resembles a flexible or rope-ladder, the chains
forming the sides and the scrapers the rounds. The
rollers c 0, round which the chains move, are boxed in
with curved pieces 7: it, so that when the scrapers
arrive with the pulp at the side extremity of any one
of the sieves, they can turn round the rollers without
losing any of the pulp, which is thus easily transferred
from a lower to an upper sieve. Jets of water j j are
constantly playing on the top sieve-frame .96, and from
this the water trickles through all the other frames, so
that by the time the pulp has arrived at the top frame
its starch is thoroughly washed out, and it is dis-
charged down the spout r. The water charged with the
fecula is received into a trough t, and passed by a
bent tube into a cylindrical sieve n, of fine wire gauze,
moving upon a horizontal axis. Here the remaining
portion of the fibrous parts of the starch cells, which
escaped separation by the sieve frames, are separated
from the starch: this fine pulp is collected in a small
receptacle r, while the starch water passes into a
trough t’ and thence into a vat v, where a danaide,
water lifter or scoop L (shown in a separate figure 1.’),
moving upon the axis of the drum D, raises the starch-
water into a trough v’, which conducts it to the
depositing vats.
The wire gauze of the frame 81, 82, &c. increases in
fineness from the top: the gauze of the top frame 86
is numbered 30, that of s1 50, and that of the drum
:0 80. These numbers indicate the number of parallel
wires in a width of 3 centimetres (1'19 inch). At
each stage are plates of galvanised iron 2'‘, i2, &c.,
curved so as to retain a portion of the water from
the jets jj, and thus act as a momentary steep for
the pulp in its passage across the sieve frames: this
prevents the pulp from forming into knots, and assists
the passage of the starch through the wire gauze.
The starch-water when received into the depositing
vat quickly deposits its starch, and forms a coherent
layer, from which the liquor is poured off. The
potatoes, however carefully washed, always con-
tain a little sand, which is now found in the first
deposit of starch, and is separated by washings and
decantations. On stirring up the starch with water
the sand subsides almost immediately; and on running
off the milky liquid into a separate vessel, a new
deposit is formed free from sand. This deposit is
covered with a light albuminous matter, which is
removed by washing. The starch is then put upon
cloths to drain, the cloths being contained in small
trays with perforated bottoms, and when most of the
water is thus got rid of, the trays are placed on a
floor composed of pieces of well-dried plaster, which
quickly absorbs the water, and leaves the starch as a
firm, friable body, which is sent to market under the
name of green/fecula. It contains about 38 per cent.
of water, and is used in the preparation of dextrine
and starch syrup, &c. To obtain the starch in a dry
state it is left for 24L hours on the plaster floor, then
cut up into blocks, and broken into lumps, and placed
on shelves in a drying-house. The pieces are turned

over occasionally, and when they begin to crack the
drying is completed at a hot stove, at a temperature
of from 55° to 58° cent. (131° to 13f)n Fahr.), with
occasional stirring, to prevent the formation of small
hard lumps, and when dry it is bolted through a silken
sieve. The substances left on the sieve are ground
under a roller, and again sifted.
This kind of starch is hygrometric, and therefore not
well adapted to the stifiening of linen: it generally
contains about 55th its weight of moisture, but when
saturated, about 23 per cent. It is often adulterated
with gypsum, chalk, and argillaceous matters, which
are easily detected by incineration. Potato starch is
sold under various names for the purposes of food.
It forms the basis of the “ nutritive farina ;” for which
purpose the starch is carefully prepared, coloured and
aromatized. “ The Prince of Wales’s food,” “ soluble
starch,” “ Indian corn starch,” “ potato flour,”
“ English arrowroot,” &c. are all chiefly composed of
potato starch. A variety of tapioca is made by heat-
ing moistened potato starch on a copper plate to
nearly 212°: some of the granules of starch burst,
agglomerate, and_form small, hard and irregular grains,
which resemble true tapioca. Starch of no kind can
be used alone in making pastry; but a little potato
starch or potato meal added to wheaten flour is
thought to improve the quality of bread. [See BREAD]
If the proportion of potato starch exceed one-fifth the
weight of the flour, a peculiar flavour is communicated
to the bread, in consequence of the presence of a
minute quantity of an oily matter contained in several
amylaceous principles, and probably identical with the
oil of potato spirit or fousel oil. [See Drs'rrrnn'rrou]
It is supposed to be a product of the fermentation of
the potato, and not to preexist in the tuber: it has
been obtained by fermenting and distilling the last
syrup obtained in the manufacture of beet-root
sugar.
Potato starch is also used in making grape or
starch sugar [see SUGAR—BEER, &c.], and British
gum or dextrine for the calico-printer. [See Gun]
It is also largely used as a substitute for glue in
making size for paper, for which purpose it is mixed
with a small quantity of a solution of resin with
carbonate of soda in water.
The starch-water from which the potato starch is
deposited is useful for the purposes of irrigation; it
contains an azotised matter and small particles of
pulp. The marc of the pulp is deprived of half its
water by expression, and is then used as food for cows
and sheep. If the quantity be too large for immediate
consumption, it may be dried at a moderate heat,
when it will keep for a year or more, and is fit for use
on the addition of water. The practice of keeping it
in heaps with salt is a bad one, as it is apt to ferment,
and thus become valueless.
The methods of preparing arrowroot, sage, tapioca,
salep, tous-les-mois, and Indian corn starch do not
require any further notice after the above ample
details, and what has already been said under Annow-
BOOT—SALEP, &c.
The duty on starch was formerly 3%(1. per pound.
S’I‘A'I‘IOS AND DYNAMICS.
673
Before being put into the stove to be dried, each
paper of starch was sealed or stamped by the Excise
officer. The duty and the restrictions imposed by the
Excise were very injurious to the manufacture; but
on the recommendation of the Commissioners of
Excise Inquiry the duty was abolished in 1833.
STATICS and DYNAMICS are two important
divisions of the science of MncHAnIcs, the one de‘
termining the conditions of equilibrium of solids, and
the other comprising the laws which determine their
motions. The other two divisions, HrnnosTATics
and HYDRODYNAMICS, refer, the one to the conditions
of equilibrium in fluids; whilst the other eomprehends
the laws of fluids in motion.
In its widest sense, Mechanics is the science of
forces, whether those forces produce rest or motion.
Forces that are balanced so as to produce rest, are
termed slalical forces or pressures, to distinguish
them from moving, deflecting, acceleraliric, or retard-
ing forces, or such as are producing motion, or a
change in the direction or velocity of motion.
Statical forces or pressures are comparable only
with each other: but the ratio between any two
quantities may be represented by the ratio between
two other quantities different in kind from the first.
Thus, two pressures may have the same ratio as two
lines, or two surfaces, or two bulks, or two times, or
two numbers: and when numbers are used, some
fixed standard is referred to as the unit of measure-
ment, such as inc/zes, feel, miles, &c., for the compa-
rison of lengths; and ounces, pounds, 850. for the com-
parison of pressures.
Forces may also be represented by lines of definite
lengths. A unit of length being taken to represent
the unit of pressure, the length of the line represents
the magnitude of the force; it may also represent its
direction, which numbers cannot do: thus, while the
direction of the line represents the direction of the
force, the commencement or extremity of the line
may represent its point of application, or the point at
which the force acts. A force being represented by a
line, a double force is represented by a line of double
length, and so on.
When two forces are in equilibrium at a point they
are equal in magnitude, and opposite in direction.
If two equal forces act together in the same direc-
tion they produce a double force; three equal forces
a triple force, and so on. Whatever number of forces
act upon a point, and whatever their directions, they
can only impart one single motion in a certain direc-
tion. Hence, all these forces may be incorporated
into one force or resultant, which is capable of pro-
ducing the same mechanical effect as the forces them-
selves, or the components, as they are called. If a new
force equal to the resultant, and acting in a contrary
direction thereto, be added to a system of forces,
equilibrium will be maintained. If a number of
forces act at a point in the same straight line, and in
the same direction, the resultant is equal to their
sum; but if the forces act in opposite directions, the
resultant is equal to their difference. Equal and
opposite forces may be added at any point without
voL. II.

disturbing a system of statical forces, a process which
is called the superposition of’ equilibrium. Equal and
opposite forces may also be removed from any point
in a system without disturbing equilibrium.
When two forces act on a point in different direc-
tions, the line representing the resultant is situated
in the same plane which contains the directions of
the two forces. When these forces are equal, the re-
sultant evidently bisects the angle between their di-
rections; but whether the forces be equal or not, the
nearer they coincide in direction, the greater will be
the resultant, and nice uersd; and as their exact
coincidence makes the resultant equal to their sum,
and their exact opposition makes it equal to their dif-
ference, so in all intermediate positions, the resultant
will be less than their sum and greater than their
difference.
If two forces be represented in magnitude and
direction by the sides of a parallelogram, the resultant
or equivalent force will be represented in magnitude
and direction by its diagonal. For example, let the
point P, Fig. 2019, be acted on by two forces pressing
in the directions BA and r B; from the point I’ on the
line I? A measure off
any length, such as
Ba; and from the point
r, on the line B B, take
a length Pb, bearing
the same ratio to Ba
that the force B bears
to the force A. This
may easily be done by
making the lines Ba,
1? 5, contain respec-
tively as many units of length, such as inches or
feet, as the forces AB contain units of force, such
as ounces and pounds. Through a draw a line
parallel to 1? B, and through & draw a line parallel
to PA, and let these lines meet at c. The parallel-
ogram B a 06 is thus obtained, of which the diagonal
Pc will represent a single force acting in the direc-
tion P c, and containing as many units of force as
the line 1? 0 contains units of length, and this force
will produce upon the point B the same effect as the
two forces A and B produce acting together.
By the same rule, any number of forces acting on
a point can be compounded. If the body ‘a, Fig.
2020, be acted on by 3 simultaneous forces, the direc—
tions of which are
represented by the
arrows AB 0, and
their magnitudes by
the lengths .r a, a b, I
we, any two of them, a; such as A and B,
may first be com~
pounded by com-
pleting the parallelogram read 6 ,- the direction of
their resultant is thus found to be .r d, and its
magnitude to their magnitudes as the length .r d
is to the lengths a a, $6. This resultant may next
be compounded with the remaining force a c, by
X X


Q.
be
Fig. 2019.



Fig. 2020.
674
STATIOS AND DYNAMICS.
completing the parallelogram a’ (l e e, the diagonal
of which, ae, represents the magnitude and direc-
tion of the resultant of all 3 forces; so that a
force of the magnitude expressed by the length .n e,
and acting in the direction ere, would balance those
3 forces. The resultant of any greater number of
pressures may similarly be found by combining two
at a time. In the problem of the parallelogram of
forces, Fig. 2019, the directions of the components
and of the resultant lie in the same plane; but in the
problem of the parallelepiped of forces, the directions
of the forces may be in difierent planes. In such
a case, the 3 lines an, ab, we, form the 3 edges,
which meet at one solid angle of a parallelepiped,
and by completing the solid figure, as shown by the
outer dotted lines, its diagonal e n: represents the re~
sultant.
The solution of the problem of the composz'lz'on of
forces, may be greatly assisted by the inverse pro-
blem of the reeolalz'on offorees. It is often necessary
to consider a force as capable of being resolved into
2 or 3 distinct forces having different directions, by
substituting for any given force a number of other
forces, with any given directions not opposite to each
other. Thus, the line we, Fig. 2020, may be made
the diagonal of any number of parallelograms, or of
parallelopipeds with their sides running in any pro-
posed directions. When their directions are decided
on, their lengths may be discovered; and thus we
may ascertain both the directions and the magnitude
of the forces into which the whole or resultant force
has been resolved.
When a number of forces in equilibrium are acting
011 a point, each force is exactly equal and oppo-
site to the resultant of all the rest. This property
leads to the theorem of the poly/yon of forces, by
which any number of statical forces are repre-
sented in direction and magnitude by the sides of
a polygon taken in order; and they will, when applied
to one point, produce equilibrium; or in other words,
in order that the forces may form a polygon, they
must be in equilibrium. For example, let P1 r2 r3 r4 r5
Fig. 2021, be forces in equilibrium acting on a point
A, and represented in magnitude and direction by the
.55 lines A]? 1, Arz,
AP3, AI’4, AP5,
To find the resul-
fll’e tant of r1 and
, r2, complete the
,,// parallelogram API
0 P2, and the re-
sultant will be
AC. Compounding
this resultant
with the force P3 by means of the parallelogram
A C 1) P3, AD represents their resultant, or the resul-
tant of r1, P2, and r3. Compounding this last
resultant with the force 1?‘, by the parallelogram
A1543 1)‘, their resultant is represented by the linenn,
opposite in direction to the last force 125, and equal to
4135. This line completes the polygon API 01) n A,
of which the sides A r‘, r‘ e, c n, 1) n, n a represent


Fig. 2021.

severally in magnitude and direction the forces
r1, r2, r3, r4, r5.
Forces may be made to act side by side with as much
effect as in the same straight line. The resultant of
two parallel/owes, as they are called, is equal to their
sum 5 it has the same direction as the forces them-
selves, and when these are equal, it is applied at a
point midway between their points of application.
When they are unequal, the resultant, although still
parallel with them, and equal to their sum, does not
act midway between them. When they are equal,
and act in contrary directions, they have no simple
resultant, for they tend to produce rotation, and this
tendency camiot be counterbalanced by any single
force. The resultant of a number of parallel forces
is obtained by a principle called the egaalz'lg/ of
moments. The point of application of this resultant
depends solely on the points of application and the
intensities of the components, and is not afiected by
any change in their directions, so long as they retain
their parallelism and equality to each other. The
forces with which the particles of a body at the surface
of the earth tend to descend, or in other words, their
weights or gravitating forces, are regarded as parallel
to one another, since they all converge towards a
point, viz. the earth’s centre, the distance of which
may be regarded as infinite compared with the size of
the body. All these equal and parallel forces may be
replaced by a single force applied to a certain point
of a body, which point of application is termed the
centre q” gravity, or the centre of parallel and equal
forces. It is a fiXBCl. point in the interior of solids,
and does not change whatever position these bodies
may be placed in with respect to gravity. (See CENTRE
or GRAVITY, where the methods of determining this
point are briefly stated.) In order that a heavy and
perfectly rigid body be in equilibrium, all that is
necessary is, that its centre of gravity be supported.
If the centre of gravity be fixed, the body may be
turned about in all directions, and it will always rest
in whatever positions it may be placed, because it will
always be in equilibrium. When a body is supported
at a fixed point, which is not its centre of gravity,
equilibrium can be maintained only when the centre
of gravity is in the vertical of the fixed point, either
above or below.
A body placed on a horizontal surface, touching it
only at one point, may assume various positions of
equilibrium, some of which are stable, some unstable,
and others inelg'firenl. When a body is disturbed
from its position of repose, and does not tend either
to regain its former position or to increase the dis-
turbance, but simply remains in the new position, it
is said to be in z'nelgferenl equilibrium. If from the’
centre of gravity of a body, rays are produced to
every part of its surface, the greater number of these
rays will be oblique thereto; some will be perpen-
dicular or normal thereto, whatever be the external
form of the body. In general, there is a maximum
ray and a minimum ray, both normal to the surface.‘
There are also other rays, which are maximum or’
minimum among the surrounding rays, and which are’
STATIQS AND DYNAMICS.
6'75
essentially normal. Now, if the body touch the hori-
zontal plane by the extremity of one of these normal
rays, the centre of gravity is in the vertical of the
point of contact, and there is equilibrium; but if the
body touch the plane at the extremity of an oblique
ray, the centre of gravity is not sustained, since it is
no longer in the vertical of the point of contact. In
general, a body is in the position of stable equilibrium
when the centre of gravity is as low as possible, be
cause in a body free to move in any direction, the
centre of gravity always assumes the lowest possible
position. If the ray of the point of contact be nor—
mal, but not maximum nor minimum, but only equal
to the neighbouring rays, the equilibrium is laclzjwreal,
as in the case of a sphere on a horizontal plane. If
a portion of the upper part of the sphere be removed,
as by drilling a hole towards the centre, the equi-
librium becomes slalle, because the centre of gravity
is brought below the centre of the figure, and the ray
from the centre of gravity to the point opposite the
hole is a minimum ray. If the hole be filled up by
inserting a plug, made so as to project beyond the
surface, the centre of gravity is thrown nearer this
projection than the opposite point, and a ray drawn
to the latter will be a maximum ray, and the balance
thereon will be aaslable, because any motion sideways
tends to lower the centre of gravity, and to enable it
to fall still lower; whereas, when a body rests on a
minimum ray, any rocking must raise the centre of
gravity, so that it will tend to fall back to its previous
position.
It has been stated that the resultant of two parallel
and equal forces, is a parallel line situated midway
between them, and that when the forces are unequal,
the resultant is so situated that its distance from them
is inversely as their intensities. Hence it follows,
that when two parallel but unequal forces are sup-
ported or balanced by a third or resultant force, this
third force must be equal to the sum of the other two:
it must act in a contrary direction, and be applied at a
point nearer the greater force than the less, its dis-
tances from them being inversely as their intensities.
When, therefore, a force applied to any point of an
inflexible bar, supports two other forces applied in the
contrary direction to two other points of the bar, the
above condition must apply. For example, when the
3 forces, B, A, and a, Fig. 2022, are in equilibrium, B
is to A as the distance Aa is to the distance Ba.
Such a case as this may represent the steelyard. [See
BALANCE, Figs. 89, 90.]
When one point of a rigid body is fixed, the effect
of any forces applied to that body is to turn it round
the fixed point as a centre of motion. When 2 points
are fixed, the motion can only be round the line or
axis which joins them. In such cases, 2 forces which
tend to turn the body in contrary directions are in
equilibrium if their intensities are inversely as their
distances from the centre or axis. But, as in every
proportion the product of the extreme terms is equal
to that of the means, we may, instead of saying that
the forces A and B, Fig. 2022, are inversely as the dis-
tances a A and a B, adopt'the simpler, but equivalent

expression, that the product of the force‘ A X the
distance a A = the product of the force B, X the
distance a B. If both forces be measured by the same
unit of pressure, and both distances be measured by
the same unit of length, the number that represents
each force being multiplied by the number that ex~
presses its distance from the axis, the product will be
the same in each case. Thus, if a straight bar, Fig.
2022, be balanced, and at the distance of 1 foot from‘
its faleram or point of support, a weight of 12 lbs.
be suspended, it will be found that this weight will
be balanced by a weight of 6 lbs. at the distance of 2
feet on the other side of the fulcrum 5 or by ll lbs. at
the distance of 3 feet 5 or by 3 lbs. at the distance of
41 feet. By multiplying these weights by the number
of units (feet) which represent the distances from the
centre, we get 12 in each case. These products
are called the momeals of the force, and it is evident
that any 2 forces applied to a body supported on an
axis, and tending to turn it round, will be in equili.
brium when the moments of the 2 forces are the same.
The moment may also be increased or decreased in any
proportion,’ and the eflicacy of the force in turning
the body round the axle will be increased or’ dimi-
nished in exactly the same proportion. So, also, by
increasing the number of forces on each side of the
axis, the body will be in equilibrium, provided the
sum of the moments on one sideuof the axis equals the
sum of the moments on the other side of the axis.
This principle of the egaalz'lg/ of moments is the most
important in the whole range of mechanical science.
It may be further illustrated by the principle of virtual
eeloez'lz'es, or that which regulates the action and con-
stitutes the efficacy of every machine in which power
is employed to overcome weight or resistance. If,
for example, 2 weights in equilibrium, as inFig. 2022,
at the extremities A and B of a bar supported on an
axis a, passing through the centre of gravity, be made

772 ‘‘~_
! §\\\
A \
t


Fig. 2022.
to oscillate gently through a small space, it is evident
that the spaces moved through by the 2 ends of the
bar will be directly as their distances from the axis;
for, the angles A a m and B a a being equal, the arcs
A m and B a are as their radii a A and a B. For in-
stance, if the weight B be 12 lbs., suspended at 3
inches from a, its moment may be expressed by the
number 36; and it will be balanced by a weight of
6 lbs., 6 inches from a, because its moment is also 36.
Now if these 2 weights be made to oscillate through
a small space, such as B a, for the weight which de-
scends, and A m, for the weight which ascends, the
latter space will be only half the former, because it
bears the same ratio to a B (or 3 inches) that A m
bears to a A (or 6 inches). Hence, if B a be 1 inch,
. Amwill be 2 inches, and the products of these 2 quanl
xx2
676
STATIOS AND DYNAMICS.
‘ of the grate being the fulcrum.
tities, with their respective weights, will be equal to
each other 5 that is, the effect of 12 lbs. moving through
1 inch, or of 6 lbs. moving through 2 inches of space,
is the same. And although we omit the consideration
of motions, and deal only with pressures, the same
principle applies to them. 2 pressures, however
unequal (a pressure of 11b. and one of 1,0001bs.,
\ for instance),'will balance each other, if they are so
‘applied that ‘the motion of ‘the first through 1,000
inches would be necessarily accompanied by a motion
of the second through one inch,’ and vice versei'. Any
means by which this connexion between the 2 pres-
sures is effected, is called a machine.
In the composition of machines there are 6 so-
called mee/iunieul powers, or more properly mee/ianieul
elements or simple mus/zines, by the combination of
which all other machines are formed. The mechanical
powers are the lever, the wheel and circle, the pulley,
the inelineclplnne, the wedge and the screw. These
contrivances are properly only applications of the
principle of virtual velocities, whereby a small force
acting through a large space is converted into a
great force acting through a small space. And in
these arrangements power is neither gained nor lost,
the whole advantage consisting in the mode of appli-
cation. llvery pressure acting with a certain velocity,
or through a certain space, is capable of being con?
verted into a greater pressure, acting with a less
velocity,‘ or through a smaller space: the quantity of
mechanical force is not altered by the change, and
all'that the mechanical powers can accomplish is to
effect this change. -
The first 'meeliunical power, the lever, is a bar or
rod, which, for the purpose of simplifying the study
of its more essential properties, is supposed to be
perfectly rigid and without ‘ weight. It may be
struiglzt or (rent, simple or eompounil. There are 3
kinds or varieties of the straight or simple lever, each
kind depending on the position of the point of appli-
cation of the moving power, and the resisting power,
with respect to a certain fixed point called thefulerum,
about which the lever is supposed to turn freely.
The portions of the lever situated on each side of the
fulcrum are called the arms of the lever.
W F 1, In a lever of the
$ ,1 first leincl, Fig. 2023,
the fulcrum n is
’ situated between the
Y moving power P and
Fig. 2023. the resistance orload
w. Levers of this kind are in very common use;
such as a crowbar used for raising stones, and a
poker used for raising the coals in the grate, the bar


1 In a lever of the
W l seeonel lsinel, Fig.
I “ ‘—1 2024:, the power P
1’ and the resistance


w, act on the same
side of the fulcrum;
Fig. 2024. the load. W being
‘between the fulcrum and. the force which moves it‘.

‘A familiar example of a lever of this kind is shown
under PARING-KNIFE, Fig. 1591, the hook at the end-
being the fulcrum; the wood to be cut is placed
under it, and is the load or resistance to be moved or
overcome; and the power is the hand of the workman
at the extremity of the blade. A wheel-barrow is
also a lever of the second kind, the wheel being the
fulcrum, the contents of‘ the barrow, the ‘weight, and
the man wheeling it, the power.
In a lever of the t/iirel lcinel, Fig. 2025, the power

and the load also act
on the same side of J,
the fulcrum, but the w‘
. ~ ‘15'

in


power I’ is between
the fulcrum F and
the load w. A fish-
ing—rod may be taken
as an example of a lever of the third kind. The
limbs of animals also furnish instructive illustrations
of this kind of lever.
It is evident from the foregoing statements, that
in all these levers the power 1? will sustain the weight
W, ‘if the moment of P equal that of the weight.
Thus. in a lever of the first or second kind, it W be
12 lbs. at the distance of 3 inches from r, its moment
will be 36, and it will be balanced by Glbs. at r, if r
be at the distance of 6 inches from r, or by r ~:_ 4 lbs
at the distance of 9 inches from F, and so on.


l
l
\..
J ll
Fig. 2025.
An example of a curved or bent lever is given "
under BALANCE, Fig. 91. For an example of the
composition of levers, see Wnrenme-Macnnvn.
The meeliunicul efiieueg/ or power of a machine is said
to be greater or less, according as the ratio of the
weight to the power is greater or less. If the weight
be 20 times the power, the mechanical efficacy is
said to be 20 : if 41 times the weight be equal to 25
times the power, the mechanical efficacy is 21-5 or 6 it.
Now, as the mechanical efficacy of the lever may be
varied by varying the distances from the fulcrum of
the power and the weight, a lever may be imagined
equal to that of any given machine; such a. lever
with respect to that machine is called an equivalent
lever. All simple machines may be represented by
simple equivalent levers, and the most complex‘
machine may be represented by a compound system
of equivalent levers, of which the alternate arms,
beginning from the power, bear the same proportion
to the remaining arms.
The chief use of the common lever is to raise
weights through small spaces, which is accomplished
by a series of short intermitting efforts, the weight
being supported in its new position while the lever is
readjusted for a fresh effort. This want of range,
and the means of supplying continuous motion, are
defects in the common lever, which are, to a certain
extent, remedied in the mole and pinion, shownin the
SCREW-JACK, Fig. 194:2 ; but in such a case the range
is limited by the number of teeth in the rack.~ By
filling up the spaces between the leaves of the pinion,
it is converted into a' eylineler or barrel, on which a
rope may ‘be coiled, and theload be suspended from it.
In such a case, the —rope will supply the place of the
STATICS‘AND DYNAMICS.
677
rack A B, Fig. 1942, and be wound up in the same
manner. This forms the common windlass, in which
the weight hanging on the rope exceeds the force ap-
plied to the winch, and just supporting it, in the ratio
that the length of the winch, measured from its centre
of motion, exceeds the rhean radius of a coil of rope,
i.e. the radius of the barrel + half the thickness of
the rope. Hence the efliciency of the windlass as a
concentrator of force is increased by diminishing the
thickness of the barrel, or otherwise by increasing the
length of the winch; but the barrel would be too
weak if diminished beyond a certain extent, and the
winch would be useless if lengthened beyond the
radius of the circle, which the hand and arm can con-
veniently describe. Hence the necessity for multi-
plying the winch or the long arm of the lever, and
making it into several radii, just as the shore‘ arm
was multiplied to form the pinion or barrel. This
repetition of the longer arm constitutes the wheel,
which, although reckoned as the second mechanical
power, is in fact only a modification of the first. The
advantage of the wheel over the single spoke or winch
is, that however long its radius, it can always be
turned continuously round by a force whose action is
confined to a small part only of the circumference.
This can be effected either by forming projections on
the rim of the wheel, to be successively acted on by
the power, in the same way that the leaves of the
pinion successively act on the resistance ; or secondly,
by passing a rope or band round the wheel. The con-
sideration of the former method must be referred to
W'HEEL-wonx; but we may here remark, that the
second method readily exhibits the properties of this
most important machine. The power is represented
by a small weight suspended from a cord, wound on
the circumference of the wheel; and the resistance by
a larger weight, on a cord wound in a contrary direc—
tion round the axle. The condition of equilibrium is
in this case the same as in the lever, only the power
is multiplied by the radius of the wheel, and this is
equal to the resistance multiplied by the radius of the
axle. If the power he 1 pound, and the radius of the
wheel 22 inches, the load 11 pounds, and the radius
of the axle 2 inches, there will be equilibrium, because
the moments are in each case the same. So also on
the principle of virtual velocities, in one revolution of
the wheel the power descends through a space equal to
the circumference of the wheel, and the weight is
raised through a space equal to the circumference
of the axle. Hence the moving power, multiplied
by the velocity of its motion, is equal to the load
moved multiplied by the velocity of its motion. The
axle of the wheel is not intermittent in its action, as
in the common lever; but the motion which the
power communicates to the load, although slow,
is constant. Hence it is sometimes named the
continual or perpetual lever, and its mechanical eth—
cacy depends on the ratio of the radius of the wheel
to the radius of the axle, or the length of the lever
by which the power acts, to the length of that by
which the load resists.
There are various methods of applying the power
L
to the wheel, such as by pins placed round its cir-
cumference, as in the wheel used to work the rudder
of a ship, in which case the hand is the power. Some-
times the rim of the wheel is dispensed with, and a
number of long bars are inserted in the axle, as in the
larger kinds of windlass, where the axle is usually
horizontal. In the capstan it is vertical. [See
OAPSTATL] In either case the wheel consists only of
diverging spokes, rendered portable by holes in the
axle, for the insertion of spokes or hand-spihes, which
are worked by men. When the axis is horizontal,
each handspike is removed from one hole to another,
the weight being meanwhile sustained by a ratchet--
wheel.
With a vertical axis a number of men may push the
bars before them, without any intermission of power,
and thus an enormous weight may be raised. Several
applications of the ratchet, or
rachel-zoheel, are pointed out
under HOROLOGY; but we
may again refer to this simple
but effective contrivance for
preventing the turning of a
wheel, except in one direction.
A catch plays into the teeth
of the wheel A B, Fig. 2026,
permitting it to revolve in
the direction of the arrow, but
preventing any recoil on the part of the weight or
resistance contrary to the direction of the power.
Levers owe much of their mechanical advantage
to their inflexibility; whereas ropes and cords
are valuable for a contrary property. A rope is a
machine which allows force to be transmitted from
one point to another in the direction of its length, but
on this condition that the opposing forces are diuel-
lent ; whereas, in a rod or lever they may act from or
towards each other. By means of the flexibility of
the rope, a force acting in one direction may be made
to balance an equal force in any other direction.
Thus the weight w, Fig. 2027, acting in the direction
RW, may, by means of a rope, g)
passing through a fixed ring R,
be sustained by a power 1?, act—
ing in the direction PR. The
alteration in the direction of


R
the power, by passing the rope P
through the ring at 11, makes no
difference in the power, but ‘
merely allows of a change in its F 'y- 2027-
direction. This supposes the rope to be perfectly
smooth and flexible, and the ring to be free from all
roughness: but as it is not possible to fulfil these
conditions, the friction arising from the opposite
qualities is greatly diminished, by substituting for the
ring a wheel grooved at the circumference, and turn-
ing freely on an axle, passing through its centre.
Such a wheel is called a pulleg. [See BLOCK] By a
proper arrangement of pulleys, force may not only be
transmitted, but concentrated. Thus the pulley is
called the third mechanical power, but no mechanical
advantage is gained from the pulleg as such, the cord
678
STATIOS AND DYNAMICS.
or rope being the efiicient agent; the real mechanical
advantage is founded on the fact, that the cord must
undergo the same tension in every part of its length.
Pulleys are fimeel or mooahle, according as their blocks
or frames are fixed or not. In Fig. 2027 the power
and the load are equal, whether the rope pass over
a fixed pulley or a fixed ring. In such a case, as
already observed, there is no mechanical advantage,
but only a convenience in being able to apply the
power in any required direction. In Fig. 2028, the
weight w is equal to 4! times the
power P. Now, the rope must have
the same tension everywhere through-
out its length, or the system would
not be in equilibrium, and in order to
be in equilibrium the tension must be
equal to the power; the power P is
supported by the tension of that part
of the rope situated between c and
r, and as the tension is everywhere
equal, it follows that the a portions
of the rope which connect the 2
pulleys, are each adequate to the
support of the power, and calling this
llb. then w will be éhlbS. In systems
of pulleys with one rope and one
movable block, the load is as many
times the power as there are different
parts of the rope engaged in support-
ing the movable block; and in general when the
power acts downwards, the number of pulleys required
is equal to the number of times that the power is to
be concentrated; but when the power acts upwards,
one pulley may be dispensed with, since, in Fig. 2028,
the power is may be applied to pull up the cord a,
without the iptervention of the fixed pulley c, which
adds nothing to the mechanical efi‘ect.
In applying the dynamic principle of virtual velo-
cities to the pulley, it will be found that whatever is
gained in force is lost in velocity: the ascent of the
weight is as many times less than the descent of the
power, as the weight itself is greater than the power.
Thus, in Fig. 2028, if the power be 11b. and the
weight dlbs, and it be required to raise the weight
1 foot, the power must descend through 4: feet ; for,
in order to raise the movable block 1 foot, each of
the 4: portions of cord by which it hangs must be
shortened 1 foot ; but as they all form parts of one
continued cord, this must altogether be shortened
4: feet, or in other words, 41 feet of cord must pass
out from the system between the blocks. Thus, no
power is gained by the pulley: its sole advantage is
to enable us to economize power, and expend it gra-
dually. In raising a weight of 50 lbs. 1 foot high, the
expenditure of power is obviously the same, whether
we accomplish the task by raising llb. through 50
feet, or 50 separate pounds through 1 foot; and in
the pulley or any other machine, a weight of 50 lbs.
cannot be raised to a given height with a less expen-
diture of power than is required to raise 100 lbs.
half that height, or 1 lb. 50 times that height.
Thefoan‘h so-called mechanical power is the inclined


Fig. 2028.

plane: it is regarded in mechanical science as a per-
fectly hard, smooth, inflexible surface, inclined 0b-
liquely to the weight or resistance. The line A c,
Fig. 2029, is called the length of the inclined plane
130 its height‘, and AB its base. A heavy body e
placed upon it will act in the vertical direction ev of
a line passing through its centre of gravity c. This
line e v may be made the diagonal of a parallelogram
ewvx, so that if
e v represent the
magnitude and direc-
tion of the weight,
it may be resolved
into the two forces
represented in direc- A
tion and magnitude
by ew and ex, one of which is parallel, and the
other perpendicular to the plane : hence the pressure
ev is equivalent to two other pressures, cw and
GK, the former of which, GW, is destroyed by the
resistance of the plane ; and the latter, e x, only acts
so as to cause the descent of the body down the
plane. New ex is to v G as B c is to AB; that is
to say, a weight placed upon an inclined plane is pro-
pelled down the plane by a force hearing such propor-
tion to the weight as the height of any section of the
plane bears to its length. If, therefore, it were
required to draw the heavy body e up the plane, any
pressure in the direction x e exceeding e x, and the
friction, would be sufficient to do so; and any pressure
in the same direction which with the friction equals
ex, would hold the weight in equilibrium.
New to test this case of the inclined plane by the
principle of virtual velocities, let the weight G be at
the foot of the plane, and the power P at the top;
then let P descend in the direction on, until e arrive
at the top of the plane. 1? will have descended
through a depth equal to the length of the plane,
while I} will have ascended through a depth equal to
its height; hence the perpendicular spaces through
which the weight and the power move in the same
time are in the proportion of their velocities. The
proportion of the weight to the power is that of the
length to the height; hence the power and the
weight are reciprocally as their virtual velocities.
P X the space through which it moves : W X the space
through which it moves. Hence, if the height of the
plane be 2 feet, and its length 50 feet, P will descend
50 feet, while W is raised 2 feet in vertical height;
and accordingly 1? must be ggth of the weight of w,
in order to effect this; or rather greater than this, on
account of friction.
When the inclined plane is movable, it is termed
the weclge, and has been called the fifth mechanical
power. In its simplest form, as _used for raising
weights, by thrusting an inclined plane‘ under 'th'e
load, instead of lifting a load by moving it along an
inclined plane, the theory is this :-—the moving power
must bear to the resistance moved the ratio which
the height of the plane bears to its hase, and not as in
the fixed plane, Fig. 2029, the ratio of the height to
the length. In the fixed plane, therefore, the power



Fig. 2029.
STATICS AND DYNAMICS.
6'79
always balances a load greater than itself, however
steep the slope may be; but in the wedge the power
and the load will be equal, if the slope be 45° ; and
if steeper than this, the power must be greater than
the load. The wedge, however, is commonly used
for separating two surfaces that are pressed together
by some force which constitutes the resistance; and
in such case it must be regarded as a cloalle wedge,
or two inclined planes joined base to base. Such a
wedge is commonly used for cleaving timber, inwhich
case the power acts by percussion. i But when re—
garded as a simple machine, the same rule is applied
to it as to other simple machines, the force acting on
the wedge being considered to move
through its length clo, Fig. 2030,
while the resistance yields to the
extent of its breadth AB. The force
of percussion dilfers so entirely from
continued forces, that it admits of
no numerical comparison with them;
that is, it is not possible to define
the proportion between a blow and a
pressure. Hence the theory of the
wedge is of very little practical value; and indeed
its most valuable property, the fiiz'elz'oa between its
surfaces and the substance which they divide, as in
the case of nails used for binding substances together,
is omitted in theory.
The earl/z mee/zaaz'eal power, the screw, is another
variety of the movable inclined plane. We have
seen, under Scnuw, that the thread may be formed
by wrapping an inclined plane round the surface of a
cylinder; and in its application as a simple machine
r“ A the power is usually trans-
initted by causing the screw
to move through an internal
screw or ma‘ N, Fig. 2031,
and the power may be ap-
plied either to turn the nut
while the screw is prevented
from moving, or to turn the
screw while the nut remains
fixed. Neither effect takes
place without producing a
longitudinal motion of one




Fig. 20 .
or the other, whichever meets with least longitudinal
resistance; but this resistance may exceed the turn—
ing power in the proportion that the revolving motion
exceeds the longitudinal motion. Thus power is
gained at the expense of motion, as in all other cases
where power appears to be increased. But in the
application of the screw, shown in Fig. 2031, a com-
pound machine, consisting of the lever and the screw,
is produced. The power is applied to the end of the
lever at P, while the weight or pressure w is sustained
by the screw, as in the common screw-press. Sup-
posing the distance, A B, between any two threads of
the screw to be half an inch, and the circumference of
the circle described by turning round the end of the
lever B to be 5 feet, or 120 half-inches, then a force
or pressure of 1 lb. at B would sustain 120 lbs. at w.
In such an example all consideration of friction is

omitted ; and this, in the ease of the ‘screw, is very
great, and is generally sufficient by itself, as in the
wedge, to balance the longitudinal force, without any
assistance at 1?. Indeed, it is seldom that any amount
of longitudinal force is sufficient to turn the screw,
for the threads would be destroyed rather than turn.
The condition of equilibrium in the screw is, that
the power, multiplied by the circumference which it
describes, is equal to the weight or resistance, multi-
plied by the distance through which the screw or nut
can move longitudinally during one turn; that is, the
distance between the centres, or other corresponding
parts of two contiguous threads, or rather turns of
the same thread, which distance (which is twice A B,
Fig. 2031, in double-threaded screws) is called the
pile/z of the screw; or the power: the weight::the
pitch : the circumference described by the power;
which agrees with the principle of virtual velocities.
The mechanical efficacy of the screw may be in-
creased, either by causing the power to move through
a greater space by increasing the length of the lever,
or secondly, by increasing the number of turns of the
thread. For if, in the above example, the pitch were
1:- instead of a an inch, the other conditions remaining
the same, the efficacy of the machine would be
doubled, and the power of 1 lb. would sustain 240 lbs.
instead of 120 lbs.
Such is a very brief notice of the mechanical
powers. For a more extended notice of them and
their applications, we must refer to other works,
such as those mentioned below,1 the first of which
will also introduce the student to the study of
dynamics, which can scarcely be entered upon in
this place; nor, indeed, will such details be expected
of us, in a work devoted to the useful arts and
manufactures, rather than to the principles of science.
But knowing how greatly the success in practice,
and the appreciation in study, of manufacturing
processes depend on the thorough knowledge and
skilful application of scientific principles, we have
been induced to insert a few short articles on those
principles, in order that the reader may be induced
to study them more fully in other works, and adopt
them as a basis in working his own peculiar pursuit,
or in studying manufacturing details.
In the science of statics, force is regarded simply
as that which is necessary to oppose or balance force.
In dynamics, force is regarded as the cause of
eiiaage of motion. Mechanical forces are considered
as motions actually produced, or tending to be
produced, without any reference to the nature of

(I) For a more extended notice of the mechanical powers, and
for the subject of statics and dynamics, the Editor begs to refer
to “Rudimentary Mechanics.” In conjunction with this work,
he would recommend the study of Mr. Baker’s “Principles and
Practice of Statics and Dynamics,” with examples wrought out
by common arithmetic; and also “ Elements of Mechanism,” by
the same writer. In this work are elucidated the scientific prin-
ciples of the practical construction of machines; while in Mr.
Law’s “ Rudiments of Civil Engineering,” with a continuation by
Mr. Burnell, the most important applications of statics to the
equilibrium of fixed structures are treated of. All the above-
named works are in MI. Weale’s cheap and useful Rudimentary
Series.
680
STATIOS AND DYNAMICS.
the force, or its generating cause. Hence two forces,
which impart to the same body the same degree
of speed in the same direction, are regarded as
identical, whether they originate from animal power,
a weight descending by its gravity, the impact of a
heavy body, or the elasticity of steam, &c. Force is
not required for the maintenance of motion, but only
for its change, that is, for producing, first, a change
of state from rest to motion, or from motion to rest;
seconvlly, a change in the velocity of motion either by
accelerating or retarding it; or tnirelly, a change in its
clireciion, by deflecting it upwards, downwards, to the
right or to the left. And since matter is inert, that
is, has no tendency either to rest or motion, a body
impressed with that motion must persist in that
motion, in a straight line, and with uniform velocity,
for ever, unless some new force, (such as friction,
resistance of the air, &c.) act upon it, either to change
its state, its direction, or its velocity; for it cannot
of itself change either its state of rest or its state of
motion, its velocity or its direction.
We may thus regard as being in equilibrium, not
only such bodies as are at rest, but such also as are
performing uniform rectilinear motion; for it is only
while their velocity or direction is changing, that is,
While they are being accelerateel, retarileil, or are
moving in a curve, that the forces acting on them can
be unbalanced, or can produce a resultant pressure;
and as long as this pressure remains unbalanced, the
motion will continue changing in velocity, or direc-
tion, or both; whenever it becomes straight and
uniform, the resultant of all the forces acting on the
body : 0, or it is not subject to any unbalanced force.
The dynamical effect of force being then a change in
motion, a continued force must produce a continuous
change, whether in velocity or direction. The simpler
effect of a sudden change of velocity, or an angular
deflection, can only be produced by an instantaneous
exertion of force, or an impact, as it is called. The
force of any moving body, or its momentum, or quantity
of motion, is the product of its mass by its velocity.
Now it is established, 1. that when equal masses are
in motion, their forces are proportional to their velo-
cities; 2. that when the velocities are equal, the
forces are proportional to the masses or quantities of
matter; 3. that when neither the masses nor the
velocities are equal, the forces are in the proportion
of both taken jointly, that is, the proportion of their
products.
These theorems may be illustrated by two balls of
clay, AB, Fig. 2032, or of some other comparatively
non-elastic substance, suspended from c by strings,
so as to hang in contact in the middle of a graduated
are D E. The are should be cycloid, and divided
not into equal parts, but as shown in the figure, so
that the numbers 1, 2, 3, &c. may be proportional to
the perpendicular heights above the level of the point
0. Now it has been proved in the case of gravity,
1st, that when a ball thus suspended is let fall from
any point of the'arc, its velocity will be the same
whatever be its mass; 2d, that this velocity will con—
tinually increase until it reaches the point 0 ; 3d, that

on arriving there, its velocity is proportional to the
square root of the vertical height which it has de-
scended ; 4th, that if it start from 0 with this same
‘Y F




Fig. 2032.
velocity, it will ascend to the same height from which
it must have fallen to have acquired that velocity and
no higher, because its velocity is by the action of
gravity constantly diminished, until at this precise
height it is destroyed. The velocities of the balls,
therefore, at the moment of their arrival at, or de-
parting from the point 0, may be exactly measured by
noting the divisions on the scale from which they have
descended, or to which they ascend, provided the 41th
division be reckoned 2, the 9th division 3, and so
on. Now, suppose these balls to be equal in mass,
and to be moved in opposite directions, A towards 1),
and 13 towards IE, and then allowed to fall at the same
moment; if the balls fall through equal arcs, they
will of course impinge upon each other with equal
velocities, and each will destroy the force of the other
and remain at rest, for equal masses having equal
velocities, must have equal forces. If, however, the
ball A be double the weight or mass of 13, and a be
raised towards D, as far as the first division, and 13
towards E as far as the fourth division; when allowed
to descend at such an interval of time as to bring
them both at once to the point 0, their velocities will
be as \/l : \/41, or as 1 : 2; but as their masses
are as 2 to 1, their forces will be as 2 X l to 1 x 2,
or equal. Accordingly, after impact, these two bodies
will remain at rest, because the equal and opposite
forces have destroyed each other. So also if the
masses of the balls be inversely as their velocities,
their forces will be equal, and they will remain at rest
after impact. If we now suppose A and B, Fig. 2032,
to be unequal in mass, but equal in velocity; that A
is twice the sire of n, and that each is allowed to
descend from the same height at n and E; if the
velocity of each be called 6, the quantity of motion
in A may be expressed by 2 X 6 =: 12, While that in
B will be 1 X 6 = 6. After impact the 6 parts of
motion in n will destroy 6 parts of the 12 in A,
leaving only 6 parts in both bodies. Now, the com-
bined mass of both being : 3, and their momentum
: 6, their velocity must be 6 divided by 3, or : 2 ;
so that both will move on together with a velocity of
2, that is, ad of their velocity before impact, and,
this will carry them g-th the height from which they
descended. Similar results will be obtained when the
STATICS AND‘ DYNAMICS—~STEAM.
681“
balls are equal in mass, but have been raised to dif- \,
ferent divisions.
If, instead of clay-balls, balls of ivory, or some other
elastic material, be used, the quantities of motion
which oppose each other are not destroyed, as with
non-elastic bodies, but reversed. If the balls be equal,
on removing A from the vertical up to any division,
such as a/ei, on the are, and allowing it to descend
and impinge on B, which is at rest, B receives the
whole of A’s motion, leaving A at rest, and starts off
with the force of A ascending the same number of
degrees on the opposite scale-that A had descended.
If a number of ivory balls of the same size be sus-
pended, as in Fig. 2033, and the
first be removed from the verti-
cal and allowed to impinge on
the others, the last only, No. 7,
is moved, and this starts off with
the quantity of motion which
No. 1 had the moment it struck
No. 2. If 1 and 2 be both raised
from the vertical, and allowed to
fall together, the last two, 6 and 7, will be raised.
When bodies move in the same direction, the phe-
nomena of impact may also be obtained if such bodies
move with diiferent velocities. Thus, if a non-elastic
body be overtaken by another, the two bodies after
impact will move with a common velocity. If they
be equal in mass, half the sum of their velocities will
be their common velocity after impact. If, before
impact, A move with the velocity of 5 and B with that
of 3, the common velocity of the two bodies after im-
pact will be 4‘, or half the sum of 5 + 3. If A and B
be unequal in mass, A being 9 and its velocity 12,
its quantity of motion will be 108. If the mass of B
be 7, and its velocity 9, its quantity of motion will be
63. The sum of the two motions will be 108 + 63:
1'71, and this will be the whole motion of the united
masses after impact. Divide this by the united
masses, 9+7 =16, we find that l71—2—16=10%%ths,
the common velocity of the united masses. When a
moving body comes in contact with a body at rest it
can- only continue its motion by pushing this body
before it, and imparting to it such a quantity of mo-
tion, that after impact they move with a common
velocity. If the two bodies be equal, the motion after
impact will be equally divided between the 2 masses,
and the velocity will be only 1-half, since the mass
has been doubled. If the mass at rest be double that
of the moving body, the velocity, after impact, will
be only l-third' of that of the moving body; and in
general, when a moving body communicates motion
to a body at rest, the united velocity of the 2 bodies
is, to that of the moving body, as the mass of the
latter is to the sum of the masses of both. .
The law of uniformly accelerated motion in the case
of falling bodies, is briefly stated in our description of
the cam, under ENVELOPE-FOLDING-MACHINE. The
pendulum is noticed under HOROLOGY. The laws of
uniformly rretarded motion, composition q" motions, pro-
jectiles, centrifagalforce, &c., are treated of in “ Rudi-
mentary Mechanics,” already quoted.



' STAVES. ‘See COOPERAGE—LEVELLING. '
STEAM, or AQUEOUS VAroUn, is the same sub-
stance which in its liquid state we call WATER, ex—
panded into an aeriform state by the addition of heat.
Steam is not necessarily hotter than water, but never—
theless always contains more heat, as will presently
appear. A large portion of the heat (or rather of the
cause of heat) in all bodies, has no effect in rendering
them hotter, and is therefore called latent heat, and of
this there is always more in a liquid than in the same
substance when solid, and much more in it when
aeriform or vaporous than when liquid. But as the
remaining heat not latent (called the scizsitle or appa—
rent heat) may be equal in all three states of the
body, all may be equally hot or of the same tempera-
ture. Thus, at all temperatures between 5° or 10°
Fahr. and 32°, water, ice, and steam have been known
to exist together, all with the very same temperature;
and although ice may seem to be incapable of being
raised to a higher temperature than 32°, yet at all
higher temperatures to which aqueous matter has
been exposed, it can exist at once both as water and
as steam, difiering not in their temperature or amount
of sensible heat, but only in that of their latent
heat. _
W'ater being the most abundant surface matter of
our planet, its vapour, steam, is the most abundant
of vapours properly so called, (that is, of aeriform
bodies capable also of existing as liquids at the same J
temperature,) and indeed, with two exceptions, is the
most abundant of all the airs or gases; for it consti-
tutes about 1-hundredth of the weight of the entire
atmosphere, and is its third ingredient in quantity,
the most abundant, namely the nitrogen, being 77—
hundredths, and the second, the oxygen, 22-hun-
dredths. The proportion of steam, however, is always
varying at any particular spot (for reasons which will
presently be explained), and always exceeds this ave-
rage in warm countries, and falls short "of it in cold
ones. Air without steam, however (theoretically called
dry air), is not known to exist in nature, and is pro-
bably not producible by art. -
Steam has the mechanical and optical properties of
common air, that is to say, it always fills any artificial
space that may be allowed it, however large, and
always presses against the whole of the enclosing sur-
faces, equally in every direction, and with a pressure
which (other things being equal) diminishes in the
same ratio that the space is enlarged, and increases in
the same ratio that the space is diminished. Although
having an appreciable and unalterable weight, it is
always many times rarer than any liquid or solid;
‘and when pure it is always invisible, tasteless, and
scentless.
The visible matter, popularly called steam, must be
carefully distinguished from steam proper, or the
aerzform state of water. The cloud, or smokelike
matter alluded to, is really not an air or vapour at all,
but a dustlike cloud of minute bodies of liquid water,
waited by a current either of true steam, or, more
frequently, of mere moist air. Thus the surface of
any watery liquid about 20° warmer than the super-
682
STEAM.
incumbent air (however warm or cold that may be)
rapidly gives off true steam, which is invisible, but
which no sooner mixes with the colder air, than much
or most of it is temporarily reeondensecl into water,
collecting into myriads of minute globes, separately
far too small to be seen, but reflecting each a point
of light, the millions of which points make the space
through which they are diffused appear like a cloudy
body, more or less white according to their abundance;
just as a space dusted with suns presents the appear-
ance which astronomers call a nehala. That these
minute bodies, although so much heavier than air or
steam, should be carried up, or at least kept from
falling, by such very gentle currents thereof, need
not surprise us when we remember that water is two
or three times lighter than carbon, which, in a similar
state of division, forms ordinary smoke, and is so
readily carried up by the hot gases from a fire.
Even glass or marble may easily be pounded fine
enough to rise with the gentlest imperceptible cur-
rents, and put on all the appearances of this water
smohc, as it might be called; and although these all
eventually fall again, so does a portion of the water,
very often, in the form of rain from the funnel of a
steamer, although in general it disappears by a re-
conversion into vapour as it spreads through a greater
quantity of air. But the watery particles are really
very much lighter than has here been supposed, as it
is demonstrable that, in all artificial and nearly all
natural clouds, they are hollow, in fact, hahhles, having
a shell of extreme thiimess compared with their
diameter. In natural clouds this has been seen by
the naked eye, Saussure having once on the Alps
been surrounded by these bubbles or vesicles, which
were as large as peas; and it is certain that the same
structure exists in clouds generally, because were its
water in the form of mere spheres or drops, however
small, a screen thereof viewed by a spectator with his
back to the sun would always present the same phe-
nomenon as falling rain or spray in the like position,
and indeed, generally, a more intense rainbow would
be seen in proportion as most cloud is more opagae
than rain, or occupies with its globules a greater
portion of the whole space through which it is
diffused. Not only does the non-production of any
such effect in ordinary clouds and mists enable us to
infer the hollowness or vesicular nature of their glo-
bules, but similar reasoning from the optical pheno-_
mena which they clo present will inform us of the very
size, form, and proportions, of these minute and in—
accessible objects. Thus, from the concentric coloured
circles, called corona, seen round the sun and moon,*
when viewed through those light varieties of clouds
called cz'rrz', and round a candle when viewed through
the light haze which is formed in an air-pump-receiver
suddenly exhausted, it is known that the cloud vesicles
in these cases must be of a certain very uniform
diameter, calculable from the measures of the coloured
circles, and found by Newton, on one occasion, to
be 5goth, on another about m‘m'th of an inch. And
where a cloud does not produce these circles, as most
do not, their sizes must be various and mixed. From

the colours, too, given by different kinds of mists to
the sun’s direct light, making his disk appear golden,
orange, blood-red, or, very rarely, rose-red, the thick
ness of the shells of the vesicles may be inferred, and
found to be from 120100,, th to 80gooth of an inch,
and more or less uniform as the colour is more or
less decided; while the mixture of vesicles of various
thicknesses will, like most natural clouds, impart no
colour, but only diminish the light by stopping all,
the coloured rays equally. The phenomena of halos,
again, show that a cloud or mist may consist of fine
dust of ice as well as of water; the varieties of
these appearances being all explained by such a crys-
talline substitute for the ordinary globules, and
even enabling us to discover the very shapes of the
crystals.
Hence we see that there are at least seven different
mechanical forms of the matter of ice, water, or
steam; three modifications of its solid, three of its
liquid, and only one of its aeriform state :—

1. Ice.
In the solid 2. Snow.
state. 3. Ice-smoke, or Halo-producing
cloud.
1. Water.
In the liquid 2.
state.
Non-vesicular, or Ptainbowpro~
ducing cloud, or Spray.
3. Vesicular or common cloud.
Inthe aeril'orm} 1
State. Steam.
The density of steam, properly so called, is less
than that of air under like circumstances; and the
relations between these densities, and, perhaps, those
of all aeriform bodies, are very curious on account of
their commensurability by simple whole numbers,
which was one of the most important discoveries of
the late Dr. Dalton, “pointing,” says Sir J. Herschel,
“to a class of phenomena of a remote and singular
kind, and of a very high and refined order,” viz.
“ such as consist in observed relations among the
data of physics, which show them to be quantities
not arhz'lrarz'lg/ assumed.” It is not a little strange
that after all the fruitless attempts of philosophers,
from Pythagoras down to Kepler, to discover such
relations in the measures and motions of the a
heavenly bodies, in which we should now as little
anticipate them as in the areas of islands, or curva-
tures of coasts, the only seemingly real instances of
such a designed simplicity of measure should now be
found in the wholly unexpected field of chemistry.
The matter of steam, or that which in its different
states we call steam, water, or ice, is a compound of
two bodies, which, as far as is known, are simple.
Always just gths of its weight are oxygen, and ash
hydrogen, (the proportion of the former being much
greater than in any other known compound, except
the very curious and unstable artificial one of
16 oxygen with 1 hydrogen). Now, when these
elements are separated, we know them only in the
state of gases, neither having been liquefied by any,
producible pressure, even in the extremest artificial
- STEAM.
* '683
Gold; and the hydrogen gas alone occupies just as
muck space as the whole compound does in the form
of steam, at the same temperature, and confined by
the same pressure; while the oxygen, although eight
tiines as much, occupies just lzalf that space; so that
these two gases separate, or merely mixed like those
of the atmosphere, fill once and a half the space that
they do when combined, and in the most expanded
state of their compound, viz. steam. This has been
found by comparisons of its specific gravity, but when
once found, it now enables us to explain, and thus to
remember the specific gravities easily; thus :—
Orze measure of hydrogen, weighing 1 lb. or oz., and
Half a measure of oxygen, weighing 8 lbs. or oz., make
_-
Orze measure of steam, weighing 9 lbs. or oz.
so that, at equal temperatures and pressures, steam
weighs nine times its own bulk of hydrogen, or an
eighth more than half its bulk (i.e. T9,; ths of its bulk)
of oxygen; or the densities of these three bodies are
as the numbers 1, 9, 16.
But in order to compare the density of steam and
air, which, omitting its steam, we have seen to con—
sist of oxygen and nitrogen, in the proportions, by
weight, of 22 to 77, or 2 to '7 ; we must next observe
that the density of nitrogen is 14 times that of
hydrogen at equal temperatures and pressures, or just
seven-eighths that of oxygen in like circumstances.
Hence '7 lbs. of nitrogen will occupy just as much
space as 8 of oxygen, or four times as much as the
2 lbs. thereof with which they are naturally mixed.
Therefore, the 7'7 parts of azote, and 22 of oxygen,
53/ weight, are, by measure, just four measures of
nitrogen to one of oxygen. If then we call the
density of hydrogen, the lightest known body, 1, and,
consequently, that of azote, 111*, and of oxygen, 16,
that of dry air must be between these two numbers,
but four times nearer to 1a than to 16, and this is
14%, or 144; or, we may add the weight of the
single measure of oxygen, called 16, to that of the
41 measures of nitrogen, or Ll times 14.‘, and the sum
7 2 being the weight of 5 such measures of air, the
weight of one must be 1404:. So that dry air is heavier
than‘nitrogen, as 35 to 36, and lighter than oxygen,
as 9 to 10; and, lastly, by comparison with steam,
this 14541 is to 9 (the density of steam on the same
scale) as 8 is to 5 ; or the densities of dry air, and of
steam equally hot, and equally pressed, are as 8 to 5 ;
and the density of all steam, whatever its tempera-
ture or pressure, has been measured by the best
experimenters as five-ei‘r/lztlzs that of dry air of that
same temperature and pressure. It has been found
so even to the fourth decimal.
The simplicity and interconnexion of these num-
bers, relating to the five commonest bodies in nature,
makes it easy to impress them on the memory.‘ The
lightness of _steam compared with the other ingre-
dients of air explains why the dampest air is, under
like temperature and pressure, the rarest; and, in
some measure, why the barometer is lower, or indi-

cates less pressure usually in wet weather than in
dry, which, however, is a more complex subject than
is commonly supposed, and cannot here be fully
explained.
It has been stated that the mechanical properties
of steam are identical with those of air; and, indeed,
as long as it remains steam, even the numerical
measures of the effects of heat and pressure on those
properties, are supposed to be alike for all aeriform
bodies. For, 1st, with regard to pressure acting alone
(i.e. supposing temperature unchanged), the bulk of a
given confined portion of steam or any air, is, as far
as experiments have gone, inversely as the elasticity
or resistance to compression; so that if, for instance,
half the confining pressure be removed, the steam, or
gas, expands into double the space it before filled,
and, of course, becomes only half as dense; and if,
on the other hand, the pressure were doubled, it
would be compressed into half its former bulk, and
thus become twice as dense, as well as twice as
elastic. This is expressed then, by saying that (other
things being equal) the density varies as the elasticity;
and it is called the law of Boyle or of Mariette,
having been independently established by the experi-
ments of both those philosophers in the seventeenth
century, soon after the fundamental discovery of
atmospheric pressure by Torricelli. [See Ara-—
Bxnonn'rnn]
Again, with regard to the effects of temperature
alone (i.e. supposing the confining pressure to be con-
stant) it is thought to have been established inde-
pendently by Dalton and Gay Lussac, at the beginning
of {this century, that (unlike solids and liquids, which
have each its own law of expansion and contraction)
all airs and vapours are aifected equally by any given
change of temperature, and that the rise from the
freezing point to the common boiling point of water,
causes arzj/ portion of them, confined by a constant
pressure, to expand t/zree-ez'ylztlzs of its bulk at the
former point. Moreover the expansion of air is
tlzeoretz'eally taken as the measure, or rather, the
definition of degrees of temperature; that is to say,
if we call the freezing point 0°, and the common
boiling point 100° (as in those countries where the
centigrade scale is used), then 50° means that tempe-
rature to which, if az'r be heated from 0°, it has
expanded half as much as in» heating to 100°. So
also on our scale, where the freezing point is made
32", and the boiling, 212°, as 8 measures of air at
the former point become 11 at the latter, when we
speak of 92°, or of 152°, we mean the temperatures
‘at which the 8 measures of air would have become 9
and 10 respectively. And as the degrees, into which
we divide the whole interval between freezing and
boiling, are 180, each degree means such a change of
temperature as will expand air 1;, of g- of its bulk
at freezing, that is, 4;, of its bulk at freezing, or 3%,,
of its bulk at 212°.
We need hardly observe, that this is a most im—
perfect measurement, or rather no measurement of
temperatare at all. The very idea of measurement
implies that equal numbers of our units, whether

osa
STEAM.
called feet or degrees, &c. should express equal
quantities of the thing measured. But here the 60°
from 32° to 92°, and the 60° from 152° to 212°, for
instance, cannot be shown to be equal intervals of
temperature, and we have no reason whatever to
suppose them so. They only express equal expan—
sions of air, and degrees thus divided can only rightly
be called degrees of air expansion, and not degrees of
temperature. To call them so is incorrect, if there
be ‘any established and precise meaning attached to
the word temperature when used apart from degrees,
and this we believe there is. We call two bodies“
equal in temperature when, being kept in contact, no
heat tends to pass from one to the other. It follows
from this that equal intervals or differences of tem-
perature can only mean such as one and the same
heat would produce in equal bulks of the same sub-
stance in the same state. And twice or ten times
any difference of temperature must mean such dif-
ference as that same heat which produced the
smaller difference, would produce in a half or a
tenth part of the matter in which that smaller dif~
ference was produced. Thus 1° of temperature must
be the difference that would be made in 10 pints
of water by the adding or taking away the same
heat that raises 1 pint of the same ‘water 10°. And
thus, if we have fixed on any two identifiable tem-
peratures, and called them 0° and 100°, then 50°
means the temperature produced by mixing equal
bulks of the same fluid, no matter what, at 0° and at
100°. And to call any other temperature than this
a temperature of 50°, is a fallacy. Yet we always
call by this name a temperature essentially different,
viz. that at which some particular substance, as air
or even mercury, would expand to a mean between
its bulk at 0° and at 100°. This point is not 50°
of temperature, but 50° of eapansion ,- and the com-
mon thermometer only measures or compares expan-
sions, although, of course, it identifies temperatures,
because a given degree of expansion of a given sub-
stance always belongs to a certain identical tem-
perature. Newton sanctioned this kind of ther-
mometer scale because the use of the instrument did
not then extend beyond mere identification, and the
important science of heat did not exist and could
hardly be anticipated. But great confusion has
arisen in most matters connected with heat, by per-
sisting in this first crude substitute for a measure of
temperature ; quite needlessly in scientific researches,
because although a true scale thereof, divided on the
above principle, might be troublesome to make at
first, it might, when once made, be multiplied, with
any enlargement or reduction, just as easily as any
of the scales of unequal parts placed on drawing and
slide rules, and would be applicable to all ther-
mometers of the same fluid as that of the original
thermometer, with the single proviso that their
tubes be of equable bore from end to end, which
is‘ just as necessary in the present division by equal
parts.
Some late experiments of Regnault and others
have made it doubtful whether the Daltonian law

applies to vapours: that is to say, whether they
expand for small increments of temperature precisely
as gases do, and Mr. G. W. Siemens has observed the
following five expansions of steam heated from 212°
upwards. If we call the original bulk of both steam
and air 660 parts, so that the air would expand one
part more for each interval called a degree, the
steam expanded 66 parts by a rise of 7° -
132 ,, by a rise of 35°;
198 ,, by a rise of 75°;
2641 ,, by a rise of 120°;
330 ,, l by arise of 165°; or that
rise which would expand air 165 parts. Thus the
difference between the behaviour of steam and air
seems to diminish as the interval of temperature in-
creases, but still to be as 2 to 1 in this case, where
the steam-expansion of i‘; answers to an air-expansion
of only 1}. Such determinations, however, are ex-
tremely delicate and diflicult, as we shall see.
But in any case, it follows from Mariotte’s law that
in whatever proportion a mass of air, gas, or vapour
might be expanded by a given rise of temperature,
were it confined by one nnvarying pressure, in that
same proportion will its elasticity or expansive force
be increased by that same rise, if it be rigidly confined
so as to occupy always the same space. For, of
course, a gas or vapour cannot exhibit expansion and
contraction by heat and eoldunless it be confined in part
by a liquid or other yielding surface. Now, whatever
rise of warmth would in this case add a given fraction,
say g-th, to the space it fills, still opposing the same
confining pressure, or preserving the same elasticity,
that same rise of warmth will, if the vapour be con-
fined to the same space as before, add %th to the
pressure required so to confine it; or, if it be wholly
enclosed in an unyielding vessel, will add -;-th to the
force with which it tends to burst the vessel.
We now come to the properties relating to the
change of state from water into steam, and vice oersel.
Whether there be any temperature below which a
given substance, water, for instance, could not exist
in the state of vapour, we have no means of deciding.
Some experiments by Faraday seem to prove that
mercury does not evaporate at all in our winter temper-
atures [see MERCURY], but we know of no such limit,
in the case of aqueous matter. Snow and ice will not,
any more than water, leave any space that is open to
them empty: they will fill it with steam, and, if the
space be large enough, will pass entirely into steam,
however low the temperature, at least so far as we
know. But, according to this, a larger space is
necessary the lower the temperature, because the
colder it be the less becomes the tension of the water
or of the snow; by which word tension we mean the
tendency to emit, vapour, and of course the vapour can
only accumulate until its pressure on the water or
the snow just balances this tendency, when all evapo-
ration must cease till there is either more space
allowed or more heat introduced. [See Evarona'rrou]
Hence, whatever be the space, large or small, steam
can only, at a given temperature, attain a certain
density and pressin'e neither greater nor less. It
STEAM;
685
requires a certain space to exist in as steam, and al-
though we may compress it into less than this space,
this can only be by a portion of it becoming water or
ice, leaving the aeriform portion still of the same
density and elasticity. On the other hand, if the
space be enlarged (without change of temperature),
more will pass from the solid or liquid state'into the
vaporous, until the same pressure as before is main-
tained, or all the water be evaporated. When this
has happened, of course any further space allowed
will reduce the density and pressure of the vapour
according to Mariotte’s law, but as long as the space
is saturated, or water be present, and prevented from
evaporating, the density of vapour depends only on
the temperature, and such is called saturated steam, and
is the only kind employed to work steam—engines.
Steam allowed to expand beyond this bulk, or the
smallest which it can occupy without condensation,
or, in short, any steam in which water will evaporate,
is called sal-saturated steam, and such is all the steam
commonly mixed in the atmosphere, for otherwise
nothing once wetted would dry—no water would eva-
porate. An enclosed body of saturated steam may
also be brought into the sub-saturated state without
expansion or any change of density, simply by raising
its temperature, for although this will increase its
pressure, it will not do so to the same extent as if
water were present, and if water were now intro-
duced, it would evaporate, until the steam became
saturated, and of a much higher pressure. Hence sub-
saturated steam, when artificially produced, is called
by engineers overheated, superheated, or sure/larged
steam, i. e. charged with more heat than is necessary
to maintain its elasticity, or with as much heat
as would maintain more matter at that same elas-
ticity. We prefer the term sutsatarated, as' the
others are hardly intelligible when applied to steam
of low temperature, as that existing in the air. We
might also call it dry steam.
It is a very remarkable fact, discovered by Dalton,
that these limitations to the evaporation of water, at
any given temperature, can only arise from the pres-
sure of its own vapour. No amount of pressure of
air or any other gas can stop or prevent the evapora-
tion of water, but can only retard it, so as to affect
the time occupied in evaporating, but not the guautitr/
of vapour sent forth to saturate the space. Thus if
water, more than sufficient to saturate a cubic foot of
space at a certain known temperature, were intro“
duced at that temperature into an empty vessel of the
capacity of a cubic foot, and also into a similar vessel
of air ever so dense; although the vacuum would be
much sooner saturated than the air, yet both, when
saturated, would contain equal weights of steam;
and whatever might be the pressure of steam in
the vessel containing steam only, the other vessel
would have that same pressure plus that of the
air; so that if the latter were 15 lbs. per square
inch, and that in the vessel of steam only were 1 lb.
per inch, that in the other vessel would be 16 lbs.
per inch.
, Thus, although the tension, or tendency to evapo-

rate, of water at common temperatures is very
small compared with the atmospheric pressure, that
pressure does not prevent its evaporating; while a
pressure only just equal to its tension, if arising from
the vapour in the air, would stop that evaporation
altogether.
But when water is heated to that temperature at
which its tension equals the whole pressure of both
air and vapour on its surface, it begins to emit steam,
not only from its surface as before, but from all parts
of its depth ; and this we call boiling. [See EBULLI-
men] The boiling-point of any liquid, therefore, means
the temperature at which its evaporating tendency
equals the common pressure of the atmosphere, or the
lowest temperature at which its vapour can have the
elasticity of common air. And as the pressure at the
earth’s surface varies in temperate climates, between
28 and 31 inches of the barometric mercury, of course
no liquids have always the same boiling-point, but
all their boiling-points are higher or lower as the
barometer rises or sinks. As a particular boiling-
point of water forms one of the defining points for
reckoning temperatures, on every thermometric scale,
it becomes necessary to fix on a certain pressure (best
defined by a certain height of the barometer) under
which pressure the boiling-point shall be taken as
100° or 212°, or whatever number of degrees we
denominate the standard boiling-point by. In this
country, the pressure for this purpose is fixed at 30
inches of mercury, so that the standard boiling-point,
or 212°, means the temperature at which saturated
steam will just sustain a pressure of 30 inches of
mercury. We call it Zita/i or low-pressure steam, ac-
cording as its pressure is greater or less than this;
and of course it follows that all high-pressure steam
must be hotter than 212°, and all saturated low—
pressure steam cooler than 212°, though it may, if
subsaturated, be as hot as we please.
Many modes have been adopted by experimenters
f or finding accurately the pressures of saturated steam
corresponding to different temperatures above and
below the standard boiling-point, but they are all
modifications of those contrived by the first investi-
gators of this subject, Dalton, Robison, and Watt.
For low-pressure observations, a barometer. has al-
ways been formed in Torricelli’s original way, by
inverting a straight tube of mercury, and dipping its
mouth into a cup of the same; but either first wetting
the closed end where the vacuum would be, or after-
wards sending up a drop of water into it. The mercury
will then always stand lower than in a common dry
barometer at the same time and place, because the
steam in the top of the tube presses so as to balance
a portionfiof the external air-pressure; so that the
difference between the mercurial columns in this and
the dry barometer will be the exact height of mer-
cury the steam would support, if acting against a
vacuum. Different temperatures were obtained by
surrounding the upper part of the tube with a vessel
of water, or snow or freezing mixture, and the results
by many observers are collected in the following
table :-—-
686
STEAM.
TEMP.
—- 3'2
88°25
122
Synopsis of Eeperz'meuzfs on the Force of
LOW-PRESSURE STEAM.
The femperatures reduced to Fahrenheit, and the pressures to
English inches of mercury.
PRESSURE-
.0000!
OIOIOI
..IICI
Ill...
OIOIII
05.09.
I r o I OI
......
0'054
'08
'12
'17
'17
'26
'28
ICC... “
OP. III
... III
IP09).
......
II’...
I.) I0.
......
Ill...
l Q I a ll
0 l 0 u OI
“OIQI
AUTHORITIES.
Gay Lussac.
Dalton.
Dalton. .
Ure.
Dalton:
Dalton.
Dalton.
Dalton.
Dalton; '25 Ure; '1 Robison.
Dalton; '23 Southern.
Dalton; ’05 Betanoourt.
Dalton.
Dalton.
Dalton.
Dalton; '36 Ure; '2 Robison.
Dalton; '35 Southern.
Dalton.
Dalton; '17 Betancourt.
Ure; '15 Watt.
Dalton.
Dalton.
Dalton; ‘516 Ure; '35 Robison.
Dalton; '52 Southern.
Dalton.
Ure. .
Dalton;
Dalton.
Dalton.
Dalton; '726 Ure; '55 Robison.
Dalton; '73 Southern.
Dalton.
Ure.
Dalton.
Dalton; '65 Betancourt.
Dalton.
Dalton; 1'01 Ure; '82 Robison.
Southern.
Ure.
Dalton; 1'05 Betancourt.
Dalton; 1'36 Ure; 1'18 Rohison.
Southern.
Ure.
Dalton.
Dalton; 1'52 Betancourt.
Dalton; 1'86 Ure; 1'6 Robison.
Southern.
Ure.
Dalton; 2'456 Ure; 2'25 Robison.
Dalton; 2'15 Betancourt,
Southern.
Ure.
Watt.
Dalton; 3'3 Ure; 3' Robison.
‘spoon
ovucui
IIIIII
l
ell-ac
IIQII.
Cl. I‘.
11'25
12'31
12'72
13'18
0.00.’
CI...‘
i)! I).
Southern; 3'5 Dalton; 2'92 Botan-
court.
Ure.
Dalton; 4'366 Ure; 3'95 Robison.
Dalton; 4'71 Southern.
Dalton; 4' Betancourt.
Ure.
Dalton; 5'77 Ure; 5'15 Robison.
Southern.
Dalton; 5'5 Betancourt.
Ure.
Dalton; 7'53 Ure; 6'72 Rohison.
Southern.
Ure.
Dalton; 7 '55 Betancourt.
Dalton; 9'6 Ure; 8'65 Rohison.
Southern.
Ure; 1068 Dalton.
Dalton; 10- Betancourt.
Dalton; 12'05 Ure; 11'05 Robison.
Southern.
Dalton. '
'2 Ure; ‘16 Southern.
'35 Betancourt.

- r'nivrr. Pnsssunn.‘ aurnomrrns.
175 ...... 13'62 Dalton; 13'55 Ure.
178'25 14'6 .... .. Dalton; 13'25 Betancourt.
180 15'38 Dalton; 1515 Urc; 14'73 Watt;
14'05 Robison.
182 ...... 16'01 . .. Southern.
185 17' Dalton; 16'9 Ure. _
189'5 18'8 Dalton; 17'5 Betancourt.
190 19' Ure and Dalton; 17'85 Robison.
192 20'04 ... Southern.
195 ...... 21'1 .... .. Ure.
200 23'6 .... .. Ure; 2351 Dalton; 22'6 Robison.
200'75 24- . Dalton; 2235 Betancourt.
202 ...... 24'61 Southern.
205 25'9 Ure.
210 28'88 Ure; 28'82 Dalton; 28'65 Robison.
212 ...... 30'00 ...... Datum of Measurement.
It has been found in these experiments that if a
minute portion of soda, or of any salt soluble in water
and incapable of rising in vapour with it, be allowed
to rise to the top of the mercury, the column imme-
diately ascends, so as to indicate a diminished pressure
of steam, although the soda has not even touched it, but
remains covered by the layer of water on the top of
the mercury. This shows plainly that the elasticity
depends not merely on the temperature and the nature
of the vapour, which are both unchanged, but on the
nature of the liquid. Because the soda has an
aiiinity for water, and cannot accompany it into a
vaporous state, it tends to restrain the water from
evaporating; and this tendency is a measurable force,
and here measured, for it partly balances the tension
of the water, or its tendency to emit steam, and thus
makes the steam-emitting tension of a solution of
soda measurably less than that of pure water at the
same temperature; so that although both emit equally
pure steam, identically alike, yet the solution cannot
support, at the same temperature, so great a pressure
of steam as the water supported, and thus part of the
steam returns into the liquid. Of course, as the
difference remains at all temperatures, the solu-
tion must always be made hotter than pure water
need be, in order to give steam of the same elasticity,
so that, ascending to that which will balance the
atmosphere, we shall find the boiling-point of the
solution higher than that of water under like pressure.
This is Well known to be the case with all solutions of
bodies not evaporable with the water. The common
boiling-point of sea—water is 215°, and of brine 222°.
The same experiment shows the nature of the
action of desz'eeuuts, or bodies that absorb steam from
the air, and so render it drier. The solution of soda
acted thus on the steam to a certain extent, and if
removed, would leave it in thexstate of subsaturated
steam, capable of taking up more water if pure water
were then introduced. A piece of dry soda would
have had a still greater effect, and it is by keeping
air in contact with sulphuric acid or with the most
deliquescent salts, such as muriate of lime, that it is
reduced most nearly to dryness.
When gases or vapours have a very greedy attrac-
tion for water, and form with it liquids less evaporablc
than pure water, they exhibit to us this steam of the
atmosphere in a very striking manner. Muriatie acid-
gas has these properties, [see HYDnooHLpnIo ACID,]
and on coming into‘ the ordinary air, it instantly picks
ETEAM‘. I
687
out the aqueous vapour, and, forming therewith a
compound less volatile than either body separately,
this compound is condensed into minute drops or
vesicles, so as to form a cloud, till by spreading through
greater space, usually far from saturated with steam,
they again disappear into vapour. But were the air
already nearly saturated, the cloud 'must fall in a
rain of dilute acid, as is often the case from the
chimneys of the manufactories of soda from common
salt. [See Sonrun] As the muriatic acid of com-
meree is always giving out this gas while open to the
air, it appears to smoke, and the same explanation
applies to the smoking of other cold bodies, as the
Nordhausen sulphuric acid, &c. Ammonia does not
smoke, although it gives out as much gas as any of
these bodies, and that gas as greedily unites with
steam. The reason is, that the compound here formed
has a lower instead of a higher boiling point than
the steam alone, so that whatever density of common
steam the temperature could support, it can still
more readily support that density of ammoniacal
steam, and therefore it remains uncondensed and
permanently invisible. For the same reason strong
alcoholic liquors, in being boiled, give elf no visible
cloud. The alcohol vapour combines with the steam
of the air, but both remain invisible.
All clouds are in fact similar to what, when occur,
ring in liquids instead of airs, is called a precipitate.
Two liquids mix and so act as to evolve an insoluble
solid, which was previously dissolved or liquid. It
either falls down in a fine powder, or is dissolved by
some further action, so as to be seen only as a tem-
porary milkiness. In the same way two transparent
currents of air, or air and steam, may, on meeting,
produce for a time, or permanently, a lower temper-
ature than can support the amount of vapour in both
together, and then some of it immediately liquefies in
the finely divided state which we call oloucl, and
eventually falls in rain, unless re-dissolved or rather
re-vaporized by obtaining either more heat or more
unsaturated space for difiusiom—and this all our
miniature artificial clouds commonly do.
Of course any subsaturated steam, as that of the
atmosphere, may be cooled down to some particular
lower temperature at which it would be saturated,
and ever so little below which, a portion of it would
be liquefied. The temperature at which any sub-
saturated steam would thus become moist steam, is
called its dew-point, because a solid cooled down to
this point would condense the steam upon its surface
in the form of dew. It is wholly immaterial to this
effect whether the steam be alone or mixed with air
to any extent. Hence the observation of this point
is the best means known for ascertaining the exact
amount of steam in the air at any time. Daniell’s
hygrometer is founded on this principle. [See Evnro-
narron, Fig. 895.]
For observations on the elasticity of highyiressure
steam, closed boilers of the requisite strength have
been fitted with mercurial gauges, that is, tubes bent
like the letter U, but with unequal arms, the shorter
inserted into the boiler, and the longer open to the

air, so that the steam pressing on mercury, in the
bend of the tube, might be balanced by a column of
mercury poured into the higher arm. The chief
results are embodied in the following table :—-
Synopsis ofEayaertmeuts ou the Force of
HIGH-PRESSURE STEAM.
The temperatures reduced to Fahrenheit, and the pressures to
English inches of mercury.
'rnMP. PRESSURE. AUTHORITIES-
212 3000
216-6 33'4 Ure.
220 35'54 Ure; 3495 Taylor; 35'18 Dalton;
35'8 Robison.
221'6 36'7 Ure.
22325 W... 37' Betancourt.
225 .... .. 39'11 Ure; 37' Watt.
226'3 40'1 Ure.
230 . .... 43'1 ... . Ure; 41-51 Taylor ; 44'6 Dalton;
44'5 Robison.
230-5 43'5 Ure.
232 44'4 .... .. Arsberger.
234 45'00 French Academicians. '
234'5 46'8 Urc; 46'8 Betancouit.
235 47'22 ....., Ure.
238'5 .... .. 50'3 Ure.
240 m... 51'? Ute; 50' Taylor; 49' Watt; 53 ‘15
Dalton; 5l'9 Robison.
2112 53'6 .... .. Ure.
245 56'34 .... .. Ure.
245'75 .... .. 58' Betancourt.
248 5 60'4 Ure.
249 59'1 Arsbcrgcr.
250 ...... 61'9 m... Ure; 60' Franklin Institute; 59'l2
Taylor; 66'8 Robison.
250'3 60'00 Southern.
250'5 60'00 French Academicians.
255 67'25 Ure.
257 72'1 Betancourt.
260 .. 72'3 ., . Ure; 701 Taylor; 803 Robison.
261 ... . 68' .. Watt.
263'8 .... .. 7 5'00 French Academicians.
265 .... .. 78-04 .. . Ure.
268'25 85'85 Betancourt.
270 86'3 . .. Ure; 825 Taylor; 941 Robison.
272 88'9 Dalton.
272 5 .... .. 82' Watt. “
274 1 ...... 88'8 . Arsberger.
275 93'48 . . . Ure.
27 5'2 .. .. 90'00 .... .. French Academ. and Franklin Inst.
2795 98' Betancourt.
280' 101'9 97'75 Taylor; 105'9 Robison.
285 . 105'00 French Academicians. ‘
285'2 112'2 . . . Ure.
290 120'15 .... .. Ure; 1145 Taylor.
2915 . . 120'00 . . . Franklin Institute.
29311 . 120'00 Southern.
293'7 .... .. 120'00 . . French Academicians.
295' 129' Ure.
300' .. . 139'7 .. Ure; 133'75 Taylor.
300'3 .. 135'00 French Academicians.
304'5 . .. 150'00 . . Franklin Institute.
305' .... .. 150'56 .... .. Ure.
308'8 .... .. 150'00 .... .. French Academicians.
310' .... . 161'3 Ure.
312' .. . 166'25 . . Ure.
314'24 .... .. 165'00 . French Academieians.
315'5 .... .. 180'00 .. Franklin Institute.
320' ...... 179'4 . .. Taylor.
320 4 180'00 .. French Academicians.
322' 176' . . Arsberger.
326'3 195'00 .... .. French Academicians.
326'5 210'00 .... .. Franklin Institute.
331 '7 210'00 French Academicians.
336' .... .. 240'00 . . Franklin Institute.
340' .... .. 231' .... .. Dalton.
3&3'6 .. . . 240'00 Southern.
3525 on’. . 270'00 . Franklin Institute.
358'8 300'00 .... .. French Academicians.
365'85 330'00 French Academicians.
a a I . ‘I
v
688
STEAM.
TEMP PRESSURE. AUTHORITIES.
372' .... .. 325' .... .. Arsberger.
374' .... .. 360-00 .... .. French Academicians.
380'66 .... .. 390' .... .. French Academicians.
383 8 .... .. 450' .... .. Franklin Institute.
386'94 .... .. 420' .... .. French Academicians.
392-86 .... .. 450' .... .. French Academicians.
398-5 .... .. 480' .... .. French Academicians.
403-83 .... .. 510' .... .. French‘Academicians.
405- ..... .- 600' .... .. Franklin Institute.
40892 .... .. 540' .... .. French Academicians.
413-8 .... .. 570' . French Academicians.
418-5 .... .. 600. .... .. French Academicians.
423 .... .. 630 .... .. French .Academicians.
427 3 ..... . _660' .... .. FrenchAcademicians. ..
431'5 .... .. 690' .... .. French Academia; 620' Arsberger.
435-6 .... .. 720' .... .. French Academicians.
Dr. Ure’s experiments were made with the follow-
ing simple apparatus' Into the globular vessel or
heater, which for temperatures above 212°. contains
oil, (the boiling point of which is nearly 600°,) the
bulb of the thermometer’ T, 'Fig. 20341, is made
|I to dip, and through another :opening is fixed the
i} sloping part of the bent glass tube, which forms
at once the boiler, steam-chamber, and baro-
metric gauge. The water
for generating the steam
consists only of a drop
enclosed between the mer-
cury and the closed end
of ‘the tube, and as the
whole. of both‘the water
and steam are always in-
cluded in the piece of tube
within the oil-vessel, they
have wholly one tempera-
ture, exactly that of the thermometer bulb; while the
mercurial column in the guag'e being almost; all out-
side the vessel and unafi'ected by the heat, no un-
certainty arises from its expansion. Two‘ marks are
made on the tube by twistingl'a fine wire round it at
the point the mercury stands at when perfectly level
in both arms, and heat being applied by a lamp under
the globe, more mercury is gradually poured into the
open -top, until ‘its inner. level, .within the. oil, is
brought ‘to-its original place, and then the height of
mercury above the mark on the upright portion
evidently measures the excess of the steam pressure
above that of the atmosphere, at the temperature
shown by ‘the thermometer at that gmoment. ' The
gauge tube is kept strictly vertical by agrooye in an
upright wooden post, and for the fine experiments 'of
the French and the Franklin Institutes, was required
to be above 60.~feet.high. ’ The French app'aratusiwias
applied to determine another'point of importance.
By compressing air instead. of steam, and carefully
measuring ‘the space occupied by a known weight of
it, they found the density so nearly proportional to
the height of mercury compressing it, that the differ-
ences were within what ‘might be expected from errors
of observation, up to the extent of their gauge, or 241
atmospheres’ pressure. This is the highest to which
the lawr of Mariotte has yet been experimentally
verified, though air is said to have been compressed
until it was denser than water, which by this-law would
require above 800 atmospheres" pressure, and makes


Fig. 2034.

it extremely improbable that the law extends so far.
Its proved extension to 241, however, in the case of air,
has led for the present to a sort of tacit assumption
that it may be relied on to that extent in steam also,
or even in all elastic fluids until the contrary be
proved. .
In a first glance over the preceding tabulated
numbers we seem to see a rule connecting the tem-
perature and elasticity, viz. that for equal intervals
of temperature, the elasticities increase by equal
ratios, so, that whatever number of degrees may
doubletheelasticity, .for instance, or increase it from
half-an-incli to one inch, the same number nearly will
again double it or‘increase it from 1 to 2 inches, from
2 to 4, &c.;and Dalton,_who first made extensive
observations of this kind, was led by his earliest ones
on low pressure steam to assume this as a law.
Further examination, however, of the tables will soon
prove to' us, as further experiment proved to him,
that such a rule, from whatever part of the series we
take it, will give, when extended to higher tempera-
tures, too rapid an increase of elasticity, and on the
otherhand, too slow a decrease in those below the
range from whence the rule was derived. Hence, Dr.
Ure contrived a modification of the rule, which is
found to give a useful approximation to the pressure
at any temperature not, morethan 609. or 80° above
or below boiling, which includesall cases now practi-
cally occurring in the ,steam engine,‘ and involves
almost nothing to tax the memory. The ratio be-
tween the elasticities at boiling and at 10° above
it, is as I to 123, three figures easily remembered.
Now the increase for the next 10°, or from 222° to
‘232°, is as 1 to 1'22; for the next step of 10Q it is
as 1 to 1'21; for the next as 1 to 1'20, and so on.
The same series, Without interruption, may be ap-
plied to the descending steps of 10° below boiling,
the first step from 212Q to 202°, diminishing the
pressure as 124*. to 1, the nextas 125 to 1, and
so on. It is thus easy ,by interpolating between
the numbers thus obtained for, the, steps ‘of 10°, to
approximate the, pressure for any intermediate degree
as nearly as can be required in the absence of the
above tables, andalmost as nearly as the most elabo-
rate _ formulae yet contrived by the mathematicians
have done. , - <
These formulae, which are very numerous, differing
rather in their constant numbers than in their form,
we do not think it necessary to explain,_‘because no
one, pretends that any of‘ them represent ‘the law of
nature. j They have a complexity and _ arbitrariness
totally unlike any natural law, and moreover, each is
only applicable, like the above, within certain limits,
above or below which it grows more discordant with
the observations the further it ‘is extended, and has
therefore to be replaced bysome other rule found
more applicable to that part of the scale. It is' as if
we were‘ attempting to fit the varying curvature of
some vast natural line, with curved'templates or ‘rulers
of different curvatures, each of which seems to fit
exactly some limited portion, but soon betrays its non-
correspondence with nature when continued far either
STEAM?
689
way. That alaw doubtless as simple as other natural
laws should still be concealed in this great series of
measurements, when in general even three or four
accurate measures of such mutually dependent quan-
tities cannot be made without at once displaying their
law of dependence, (as when Kepler, from the rela-
tions of distance and periodic time in two planets, for
instance, was led to the general law connecting these
two elements in them all,) and that it should even re-
main thus concealed, after all the mathematics brought
to bear on them by Laplace, Arago, Biot, Prony,
Ivory, Tredgold, and many calculators of hardly less
eminence, may seem strange at first, but is really just
what might be expected, if we remember what the
quantity here miscalled the temperature really is. As
already pointed out, it represents no measure of a
simple natural quality or quantity, (such as heat or
density or pressure,) but only of one peculiar and pro-
bably complex effect of heat. It is a mode of com-
paring and identifying temperatures, just in the way
that degrees of moisture were once compared and
identified by their relative effects in lengthening or
contracting a hair, or just as the mineralogist still
distinguishes degrees of hardness, by the ability to
scratch or to be scratched by certain conventional
standard substances. We might as well weigh bodies
by measuring the extent to which they will bend a
spring of a given identifiable stiffness, and this would
answer all the ends in regard to weight, that the ther-
mometer or the above contrivances were intended to
do, and indeed do in their common every day use, for
mere identification. But we could not meiy/i with
a spring-balance (i.e. measure weights) if its degrees
were formed with reference only to spaces on the
scale, or expressed equal amounts of bending. We
might call the numbers on such a scale indeed the
weights of bodies, (just as we call those on the ther-
mometer scale their temperatures,) but any inquiry
involving precise relations of real weights would
expose the fallacy in that case, as in this. We should
be a long time learning from those numbers the law
of c/zemical equivalents for instance, twist and torture
them as we might. Now the laws of heat are sought
from precisely such data as these would be. Why
expect any equation simple enough to be discovered
by chance, between two quantities so remotely con-
nected as the elasticity of steam and the difference of
the expansions of mercury and glass by the tempera-
ture of that steam? The first application to these
measures of a real t/iermometric scale,—-one of equal
degrees of iieat, instead of equal degrees of expansion,
-—will probably at once make evident the law that
has baflled and must baffle these, as we think, ill-con-
sidered exercises of misapplied mathematics.
It is conceivable, too, that the relation between the
temperature, truly measured, and the density of the
saturated steam, may be simpler than between the
temperature and the elasticity. As doubts are now
thrown on the applicability of Dalton’s and Gay
Lussac’s law of gaseous expansion to this vapour, we
can no longer, as heretofore, look on the densities as
calculable from the other two elements, temperature
VOL. II.
and elasticity, when the density for one particular value
of them is once determined; and direct measures of
the density are so delicate and difficult, that we fear a
series of them will long be a desideratum. On the sup—
position, however, of steam following strictly the same
law established by those philosophers in the case of air
and several gases, so that any two of these three ele-
ments being given the third would be known, the fol-
lowing table has been computed, to show the general
march of the density-and other chief properties of satu-
rated steam for an extreme variety of temperatures.
Properties of Steam and Water at Difl’erent


Temperatures.
I M ' Q ' ".50
c. ~ g. a. e .__.s
z,-
yrs
as at 52 St’: 3‘; 5% it???
its as as "as: "05 as see
E-¢ Q4 [-t > > F=1 Q
- 3-2 0-054 1-555th 1'0036 easooo- 632722 1-sssa1
+10- '12 1-250a1 1-00174 294924. 294412 1-400th
39- ~33 1-90th 1'00000112895' 112895 1444a
65- ‘75 1-40th 1-00144 52855’ 52779 1-e4tu
100' 2- 1.15m 1'0072 21173- 21021 with
140- c- l-5th 1-0179 7573- - 7439 l-Sth
180' 15- l-half r0314 3235- 3136' am
212- 30'-—One———1'0433—-—-1700'—-—-1630'-——- -625
250-5 so- Two 1-058 900- 850'? 1-25
293-7 120- Four 1'075 err-s 444-3 2-3
358-8 300- Ten 1-090 zor-s 190-6 6'25
418'5 eoo' Twenty 1-122 111-5 99-4. 12's
45in‘ 900- Thirty 1'136 77-7 67'5 18'75
ass-s 1200' Forty 1-147 602 52s 25-
510'6|1500- Fifty 1155 49-4 42-77 I 31-25


The corresponding temperatures and elasticities are
here taken from Dalton for low-pressure steam, from
Dulong and Arago for high-pressure. The fourth
column is then calculated thus. The volume of an
unit of water at 39° (its point of greatest density)
being taken as unity, the space which it would occupy
at any other temperature is taken from the observa-
tions of Kirwan and Gilpin, up to 212°. But as
these measures were made under the constant pres-
sure of one atmosphere, while the water is here sup-
posed subject to the varying pressure of its own
vapour only, the correction for this is reckoned from
Perkins’s experiments on the compression of water,
and found not to afiect the last decimal here given.
Although we have no measures of water at the two
temperatures below freezing, it is known under these
circumstances to go on expanding by cold, and these
volumes have been reckoned by the empirical formula
that Dr. Young found to represent very closely the
expansions both ways from 39° as far as they had
been measured. But in applying Dr. Young’s rule
above 212°, we find it give a maximum volume at
about 360°, above which it makes the water contract
by heat as fast as it had previously expanded. So
anomalous an effect could only he admitted on experi-
mental proof. Until further observations, therefore,
had been made, we could only, as a more probable
supposition, reckon these volumes by a regular
expansion at the rate Gay Lussac measured in the
last few degrees below boiling; and then reduce
Y Y
690
STEAM.
them for the compression caused by the steam, which,
however, only affects the last decimal in the last two
numbers. This shows that at 510° we are still far
short of the temperature at which water would cease
to expand, being stopped by the pressure of its own
steam, balancing its own tendency to dilate. The
next column, headed “Volume of Steam,” is based
on the number 1,7 00, which, according to Gay Lussac,
represents the space that one measure of water at its
greatest density will occupy when converted into
boiling steam. To obtain the space occupied at any
other temperature, we first increase or diminish this
inversely as the pressure in the second column, and
then increase or diminish the resulting number, by
gg-ath of itself for every degree above or below 212°.
For instance, if the 1,7 00 measures of steam of one
atmosphere were to expand without change of tempe-
rature, till its elasticity were reduced one-half, it
would, by the Boylean law, occupy twice its former
bulk, or 3,400 measures; but it would not then be
saturated steam, but subsaturated, having only half
the density and elasticity its temperature could sup-
port, and capable of taking up its own weight of
additional water. In other words it would be over-
heated steam, having at 212° only the pressure
belonging to saturated steam of 180°. It would be
like the steam of the atmosphere, a dry or drying
steam, one in which water could evaporate, or wet
bodies of its own temperature be dried, and so could
any bodies hotter than 180°. But 180° would be its
dew-point, down to which it must be cooled before
any would condense into water, or at which point it
would become saturated steam. Hence the same
quantity that as steam of one atmosphere filled 1,7 00
measures, plainly cannot, as saturated steam of half
an atmosphere, fill 3,400 measures, but to find its
new volume we must diminish this 3,400 in the pro-
portion that airs under a constant pressure contract
in cooling from 212° to 180°, that is (if the Daltonian
law apply here) in the proportion of 448 + 2l2 to
448 + 180, the volumes being, according to this law,
proportional to the temperatures reckoned from 448°
below Fahrenheit’s zero. We thus diminish it to
3,235, which expresses the smallest space in which
1,700 measures of boiling steam would cool to 180°
‘without depositing any moisture, or the smallest in
which one measure of water at 39° could pass wholly
into steam at 180°. Or, again, if 1,700 measures of
boiling steam could be compressed by an additional
atmosphere without any being liquefied, they would,
like air or gas, occupy under this doubled pressure
only half their former bulk. But it is impossible to
compress this or any saturated steam ever so little,
without liquefying a part, unless we add at the same
time heat enough to raise its temperature to the point at
which water boils under this increased pressure. Thus
we cannot possibly have steam of one atmosphere
cooler than 212°, nor steam of two atmospheres below
25 05°, (though as much above these temperatures as
we please.) It follows, then, that the water which at
212°requires 1,7 00 measures to exist in as steam,
must at:250%°, though twice as elastic, require more

than the half of this,—~m0re than 850 measures, in
the proportion that air under a constant pressure
would expand if heated from 212° to 2505?; and by
increasing the 850 in this proportion we obtain very
nearly 900 for the smallest space in which 1,700
measures of boiling steam (or one measure of water
in its densest state) could be wholly converted into
steam of two atmospheres, or of 250%".
The numbers in the sixth column are found by
dividing each of these volumes of steam by the
volume which it occupies as water at the same tempe-
rature; and those in the last are all -§—ths of those in
the third, because we have seen that all steam is pro-
bably gths as dense as air of the same temperature
and pressure. This column shows us, that while
steam of the high pressures observed by Dulong
and Arago is by far the densest aeriform matter
known, the steam of low and common temperatures
presents the lightest form of matter of which we have
any evidence (it that of comets be excepted); that
which depressed the mercury of Gay Lussac’s baro—
meter in his coldest observation being probably 888
times thinner than air, while even at summer tempe-
ratures, in which he contrived with exquisite ingenuity
to submit it to actual weighing, it is the lightest
body ever weighed, hydrogen having only been weighed
at the common pressure, under which it is much
denser than saturated steam of 100° Fahr.
As we see that with increase of temperature the
liquid and its vapour both tend to approach each
other in density, the water becoming expanded and
the steam at the same time rapidly denser, so that
while ice at zero (supposing it one~tenth rarer than
water at zero) requires more than half-‘a-million times
its own space to evaporate in, water at 510° requires
only 43 times its space ; a question naturally arises
whether there be not some higher fixed temperature
at which the two forms of this substance would be
equally dense, and thus merge into one, the distinction
of steam and water no longer existing; or rather a
temperature above which water could not exist, but
steam, however much compressed, even to the density
of water, would remain permaaeatly gaseous, as air
and hydrogen seem to do at common temperatures.
On this point, M. Cagnard De la Tour made some
curious experiments, and is said to have heated
alcohol and ether, enclosed in glass tubes, to tempe-
ratures at which they became wholly vaporous and
invisible, in little more than the space they occupied
as liquids,——and water in about four times that space,
at a temperature about that of melting zinc, above
which the experiments were prevented by the solvent
power of this liquid becoming so increased as to
attack any kind of glass. Supposing the temperature
7 00°, this would make steam of that temperature 425
times as dense as boiling steam, and, of course, if the
Boylean law extend so far, 425 times as elastic as
boiling steam (or atmospheric air) would be if heated
from 212° to 700°, without change of density, or with
neither access of water nor room for expansion. An
aeriform body so heated would, by the Daltonian
law, have its elasticity increased as 448 -l- 212 to
~SIlEAM.
691
448 + '7 00, or as 660 to 1,148, and by increasing
4:25 in this ratio we get 739 atmospheres for the
pressure probably borne by M. De la Tour’s glass
tube. This is the nearest approach to the yet un-
solved problem of “making water red-hot.” It is
well-known that in red-hot metallic vessels, it does
not touch them, nor become much hotter than 210°,
nor produce steam nearly so elastic as the atmo-
sphere. [See EBULLITIONJ The luminous film of
every hydrogenous flame may be regarded as red or
white-hot slerim, and shows that the rarity or transpa-
rency of aeriform bodies prevents their giving, at the
intensest degrees of incandescence, so much light as
solids give at far lower degrees. In ordinary flames
it is the light of incandescent carbon only that we
use, and it entirely drowns that of the equally hot
newly formed steam or carbonic acid.
We have now to explain how it is known, that
although steam and water can thus co-exist at almost
every measurable temperature, the steam has always,
as stated at the outset, more heat than water has.
We know that the visible cloud commonly called
steam is never so hot as the liquid whence it comes,
and will never even scald the hand, although the
steam from a boiling kettle will do so, while in its
invisible state, or before it becomes cloud. But a
thermometer plunged into even this invisible part of
the current will never mark a higher degree than in
the water, rarely so high; and never in any case
higher than 212° in the open atmosphere. Hotter
than this, no steam can be made without forcible
confinement, and then the water also is made equally
hot, a thermometer placed in a high-pressure boiler
marking exactly the same degree whether in the
water or the steam. And in the jet issuing from such
a boiler, it will never even rise to 212°, as in that
from a tea-kettle, however hot the steam immediately
within may be; for so universally is all visible cloud
colder than this, that the jet from such a boiler,
which, unlike that from a tea-kettle, becomes visible
imiizecliazfelg/ on passing the aperture, will not scald a
hand however close it may be held ; which has given
rise to the absurd paradox that “ high-pressure steam
will not scald;” whereas high-pressure steam has
never been touched, nor can be, unless by making the
hand a valve to help confine it; for when it has issued
from a jet, it has ceased to be high-pressure steam.
Notwithstanding all this it has been usual, from
the time even of Hero, the Alexandrian writer on
Pneumatics, 2,000 years ago, to speak of water being
converted into steam by the addition of heat, or, as
he expressed it, “ converted into an air by fire,” the
four popular “elements” having then been under-
stood as simply the names of four states of matter,
solid, liquid, gaseous, and imponderable, in strict
accordance with our latest science. It was impossible
to overlook this absorption, or expenditure of fire or
heat, in converting water into an air; a portion of
both constituents, the water and the heating power
or principle, being evidently lost‘ as such, or ceasing
to show their characteristic qualities, in uniting to
form the new substance. Yet it was not until about

the middle of the last century that one of our great
thinkers, Dr. Black, began to reason precisely on so
common a matter, and to deduce from it some highly
important natural laws. [See HEAT.] He proved
that this disappearance or apparent loss of heat took
place whenever a solid melts, as well as when a liquid
evaporates; and on the contrary, a precisely equal
apparent production or restoration of heat when the
same liquid solidifies or the same vapour liquefies.
For instance, if a quantity of ice, some degrees colder
than freezing, say at 20°, be placed in ever so warm
a situation, even in a vessel over a fire, although its
temperature will rise to 32° just as quickly as an
equivalent mass of any other body (5. e. a mass having
the same heat-capacity) would rise 12°, yet its tem-
perature will then remain at 32° during the Whole
time occupied in melting, which of course will be pro-
portioned to the quantity melted; and not until the
whole has become water will a thermometer in it
again begin to rise as before. During all this time
heat enters the ice, and yet neither that nor the ice-
water, nor anything that we can observe, becomes
hotter. We see that heating power is expended just
as if the contents of the vessel were being warmed,
and yet they are not warmed, but only mellecl. A
change is effected, more and more of the solid becomes
liquid, and we see that a supply of heat is necessary
to effect this, but when all is over we have no more
apparent heat, nothing holler, only a vessel of water
at 32° instead of ice at 32°. Dr. Black showed, and
it is perfectly established and demonstrable in a va—
riety of ways, that to melt ice simply without any
rise of temperature, it must always thus receive and
absorb, or render lateral, a certain precise amount of
the heating power or principle, viz. about as much as
would heat an equal weight already melted no less
than 140°. So also, in the melting of all other solids,
there is a fixed quantity of heat, different for each,
and generally greater than this, rendered latent; and
in the conversion of liquids into vapour, a generally
greater quantity still; which in the case of steam is
greater than in any other case known, being little, if
at all less than would have heated the water, if it
could remain water, 1,000°,——(or ten times as much
water, 100° ; or a thousand times as much, 1°). The
various modes of determining this number are exactly
analogous to those by which the 1ét0° absorbed in
the liquefaction of ice are ascertained. Thus, as the
vessel in which ice is melting, so also that in which
water is boiling, can be made no hotter by any heat
we may apply, until the whole has boiled away. The
only effect of a fierce fire is to melt the ice more
quickly, or to evaporate the water with greater rapi-
dity, but not to render either hotter. Now Dr. Black,
by contriving to keep a plate of iron at a constantly
equable red-heat, and placing on it a small tin dish of
water, compared the time occupied in heating it from
50° to 212°, which was a minutes, with the time after-
wards required to boil it all away. This, however, is
the least accurate method of any, and gave only an
approximation to the relative quantities of heat ex-
pended. A better method is that called the method
x Y 2
692
STEAM.
of mixtures. In melting ice by water, it will be found
that if the weights of water and ice be equal, the re-
sulting water is 7 0° colder than the mean of their
temperature before mixing. Thus, no ice can be
melted by its own weight of water of a lower tempera-
ture than 172°, or as many degrees above 172° as the
ice is below 32°; and in this case the resulting water
will be only just above freezing. It will be the same
when ice is melted by 10 times its weight of water
141° warmer than itself; or 5 times its weight 28°
warmer; or 28 times its weight 5° warmer; these
being the smallest quantities that can melt it in those
cases. So in condensing steam by passing it through
water, one of Watt’s first‘ experiments, he was asto-
nished, till Dr. Black explained to him his theory, at
the large quantity of water that a little steam could
raise to nearly its own temperature. That steam at
212°, may become water at 212°, it must give out heat
enough to raise, according to Rumford, 10 times its
own weight of water 102°, or produce an equivalent
effect, such as heating 102 times its weight 10°, or
1,020 times its weight 1°; and though this is the
highest measurement, the lowest, that of Southern,
makes the number 9412. Another mode of proof by
Watt is very remarkable. We have seen that, under
forced confinement, water may be heated much above
212° without boiling, that is to say, any boiling will
cease as soon as the confined steam acquires the den-
sity of saturated steam for the particular temperature
maintained. I’apin, who, about the year 1700, iii-
vented the safetyfvalve, [see DIGESTERJ applied it
chiefly to a small culinary vessel for the highly useful
purpose of extracting nourishment from bones, &c.
by water of higher temperatures than boiling, and it
is called after him Papin’s digester. Now, however
hot the water in one of these may be made, it is
found that, on opening the valve, only a part of the
water rushes out in steam, (instantly becoming a
dense and colrl cloud,) and what remains as water
instantly cools to 212°. The hotter the original tem-
perature, the greater portion indeed rushes out, but
nothing remains hotter than 212°. Moreover, if the
whole were previously 95° above boiling, just a tenth
of it will thus rush out, so that this tenth, in changing
from water at 307° to steam at 212°, taloes nevertheless
as much additional heat as raised all the other 9 parts
95°; or in simple conversion into steam it absorbs as
much as raised all 10 parts 95". If all were heated at
first 190° above boiling, then the portion flying out
‘will be grth, so that it requires for vaporization, i11-
‘dependently of all change of temperature, 5 times the
‘heat that would raise it 190° without evaporation.
‘And in every case the same rule will apply, the part
evaporated bearing that ratio to the whole, which the
degrees it was raised above boiling bear to 950°.
Important as this quantity, called the latent lzeat of
steam, and all laws relating to it, must evidently be
to the economy of the steam-engine, affecting funda-
mentally all questions as -to the best form of engine
‘or mode of working, it camiot be said to be either
‘more precisely known, or the least better understood,
*as to its laws now, than in the time of Dr. Black. )
Two rules leading, if followed out, to the most oppo-
site results, have, until very lately, if they do not still,
appeared in the same books, or almost the same pages,
without a remark on their incompatibility, and are
alternately and indiflerently taken for granted in the
same calculations. The first, which is attributed to
Watt, and seems, at one time at least, to have been
accepted by Dalton, is to the effect that the higher
the temperature, the smaller, 63/ just so many degrees,
is the difference of latent heat between steam and
water at that temperature. The other rule, founded
on three experiments by Southern on steam of a, 1,
and 2 atmospheres, or 180°, 212°, and 250$;O only,
assumes this difference to be constantly equal at all
temperatures, being always such as would raise water
942° or 950°, for to this extent did even those three
experiments vary.
The former, or Watt’s rule, is commonly expressed
by saying that the total heat of saturated steam (i.e.
the latent and apparent heat together) is a constant
quantity, viz. in round numbers 1,200° on Fahren—
heit’s scale, so that when the temperature or apparent
heat is 212°, the latent will be 988°,—when the for-
mer is 250°, the latter is 950°, &c. In Southern’s
rule the latent instead of the total heat is constant.
But as the quantities are expressed in degrees that,
as we have seen, measure no causal force, only an
effect. whose laws are unknown, it is not at all likely
that either these or any other modes of reckoning
founded on our present thermometric scale, will agree
with the phenomena. Some experiments of Regnault,
made by the direction of the French government, have
rendered it certain that the truth lies between these
two hypotheses, or that saturated steam contains
more heat the hotter it may be, but less latent heat.
The rule he has deduced, however, as agreeing best
with his experiments, is very arbitrary, and unlike the
simplicity of a natural law. It amounts to this, that
for every increase in the density of saturated steam,
there must be an increase of the total heat equivalent
to 305 per cent. of the rise of temperature; or, in
other words, the difference between the heat latent in
the steam and in the water, is neither constant, as
Southern supposed, nor does it diminish as much as the
temperature increases, as Watt supposed, but about
7-tenths as much, viz. 695 per cent. Thus the truth
would lie nearer to Watt’s supposition than to South-
ern’s, as '7 to 3 nearly. The latent heat, in saturated
steam of the following different temperatures, will be,
according to the three hypotheses, as follows :~—-


x‘.
2 £1 WATT. REGNAULT. SOUTHERN.
(U 0 O .
5% g Latent Total Latent Total Latent Total
; g [,3 Heat. Heat. Heat. Heat. Heat. Heat.
deg. deg. deg. deg. deg. deg. deg.
180 1} atm 1020 1200 988'4 1168'4 950 1130
212 1 ,, 988 1200 9662 1178'2 950 1162
234 1% ,, 966 1200 9509 1184'9 950 1184
251 2 ,, 949 1200 939 1190 950 1201
276 3 ,, 924- 1200 921'7 1197'7 950 1226
294 4 ,, 906 1200 909-2 1203-2 950 1244
321 6 ,, 879 1200 8903 1211 -3 950 1271
360 10 ,, 840 1200 8633 12233 950 1310


STEAM.
693
"What is here called the total heat, however, should
be called the excess above that of water at 0° Fah.
It has been justly observed that the greatest incon-
venience of 'this scale is its not having the zero at
that great natural standing point, the congelation of
water. In the thermometric systems of the conti-
nent, where this is the case, the number in question
represents the excess of heat in the steam above that
of freezing water, which is an actual and well-known
standard; whereas, water at 0° Fa/a, which we are
obliged to refer to, has never been seen. We might
add 140° to the above numbers, and call them the
excess of heat above that of ice at 0°; or what is
much better, diminish them by 32° and call them the
excess above freezing water; but this would lead to
continual mistakes unless we also reckoned the tem-
peratures from the freezing point.
Again, it is necessary to remember that the latent
heat is measured by the number of degrees it would
warm an equal weight of water, (or rather the number
of such weights of water that it would warm l°,) and
that its effect on any other body, or even on the
same body in the state of steam or of ice, would be
quite different. From observations of the warming
and cooling effects of different substances on each
other at different temperatures, as well as from the
different expenditures of fuel to heat them equally, it
is clearly proved that the same quantity of heat
which warms a pound of water 1°, will warm a pound
of most other bodies much more than 1°, and a pound
of mercury no less that 30°, or at least 30 pounds of
it 1°. A pound of water and 30 pounds of mercury
are therefore eqaz'valeats in regard to heat. Both
have the same heating or cooling effect on the same
body, when their temperatures are equal, and this is
commonly expressed by saying they have the same
capacity for heat. But if so, a pound of water must
plainly have 30 times the capacity of a pound of
mercury, and must (when their temperatures are
equal) contain 30 times as much of that heat which is
employed in maintaining their temperature, leaving
latent heat out of the question. For when an addi-
tion of heat is so shared between these two bodies
as to have no tendency to leave one and enter the
other, the water will have 30 times more of it than
the mercury, though both will warm a thermometer
equally, or have the same effect on any body touching
them, in short the same temperature. Hence, if we
call the capacity of any quantity of water 1 or 1,000,
that of an equal weight of any other substance is
called the specific heat of that substance, and is, for
almost all known solids and liquids, considerably less
than this unit of comparison. If these specific heats
were expressed by the numbers representing the
capacity of equal bat/ts of the different bodies, instead
of equal weights, they would be much less widely
unequal, though the numbers would still be less for
almost all other bodies than for water. Again, when
a given weight of any substance is expanded into
a larger space, whether by heat or any other cause,
its capacity is increased, so that the specific heat
of the same substance is greater or less according

as it is rarefied or condensed. Ice and water are
an exception to this rule, but an instance of a more
general one, viz. that the same substance has always
a greater capacity or specific heat when in the liquid
than the solid state, and it is generally supposed to
have a greater still in a gaseous state. In expressing,
therefore, the quantities of heat that disappear, or
that seem produced in any process, it is necessary to
say on what substance their effect is reckoned. This
is generally water, and from it we can of course
estimate the number of degrees change (usually
greater) that would be produced in any other body
whose specific heat is known.
Dr. Dalton contrived the following elegant mecha~
nical illustration, or rather way of better conceiving
these changes and their curious effects in liquefaction
and vaporization. Let there be three concentric
cylinders with open tops, of unequal diameters and
heights, placed
one within an-
other, and the l‘ .
outerrisinghigher
than the second,
and the second
the;
-_._—_- -_---_,.
l
- l
than the inner- B most; and let a ' slender tube pro- Al ll
ceed from the bot- .
tom of the inner- l
most, through the ' l
sides of the others,
and turn up ver~
tically as high as
the outer vessel,

Fig. 2035.
i to serve as a gauge of the height a fluid may attain
within them. Now if water be poured into the
inner vessel, its rise will be accurately indicated
by this gauge, till it arrives at the level of the inner
vessel’s top, and begins to overflow into the next
larger vessel. No addition will now be at all indicated
by the gauge, till the space surrounding the inner
vessel has been filled up to the same level. T/zea,
indeed, the gaugewill again begin to show the rise of
liquid, but will rise more slowly than before, if the
supply continue uniform, because the area of the
second vessel is larger than that of the first. This
represents the thermometer indicating the addition of
heat to ice till it arrives at 32°, then remaining
stationary till all is melted, and again rising more
slowly in the water, for an equal supply of heat, because
its heat-capacity is greater than that of ice, So when
the liquid arrives at the top of the middle vessel and
again begins to overflow, the level will remain sta
tionary a longer time, because a larger space has to
be filled up than before, and we may make this space
exceed the former in the ratio of 7'6 to 1, (in
which ratio the heat absorbed or rendered latent in
boiling water into steam, exceeds that in melting ice
into water,) and at the same time make the horizontal
sections of the three vessels as the numbers 900,
1,000, and 1,550, the relative capacities of ice, water,
and steam; and again make the space around the
094
STEAM—STEAM-ENGINE.
inner vessel bear to that above its top between the
levels A and B, the ratio of 140° to 180°, that of the
heat absorbed in liquefaction to that employed in
raising water from freezing to boiling; and all the
phenomena will be proportionably represented.
As all uniform bodies yet tried, undergo a change
of capacity by change of bulk, a sudden compression
or rarefaction alters momentarily their temperature;
which is immediately restored by the communication
of heat to or from surrounding bodies. Thus air very
quickly compressed into a tenth of its bulk or less,
by a blow on the piston of a small syringe, is well
known to ignite a bit of German tinder; and on the
other hand, if suddenly allowed to expand into twice
its former bulk, it becomes for the moment as cold
as the air at that height in the atmosphere where it
is only half as dense as at the place of the experiment.
But in thus becoming colder, it loses no heat or
caloric. It is colder only because that same amount
of caloric which maintained it at the common tempe—
rature when in the smaller space, cannot do so when
spread through a larger space. More heat therefore
enters it to restore the equilibrium, and this seems to
be so much heat lost or rendered latent; but it is
again given out if the air be again compressed to its
former bulk.
Now there is no doubt that similar effects would
attend the compression and rarefaction of steam; and
the common or Watt’s hypothesis respecting the vari-
ation of its latent heat is founded on this, and on a
supposition of Watt’ s, which rests on no experiment,
and seems to admit of no direct trial, viz. that if an
enclosed mass of saturated steam were thus enlarged
or compressed, to any extent, in a vessel'z'mpervz'oas to
izeat, its own heat, without addition or diminution,
would always just maintain it in the state of satura-
tion. Thus compression, which in all attainable
circumstances of the experiment, causes some of the
steam to liquefy, would not, as Watt supposed, do so
if no heat left the vessel, but would raise its tempe-
rature exactly to the point at which steam can support
this increased pressure. And an enlargement of space
would, as he supposed, reduce its temperature to the
lowest at which steam of this reduced density can
exist. When, indeed, high-pressure steam escapes
into the open air, it is partly condensed into cloud,
because, besides the reduction of temperature by
expansion, it also imparts heat to the air.
It will be seen that on Regnault’s hypothesis, and
still more on Southern’s, a mass of saturated steam
cannot by compression raise its own temperature high
enough to prevent the liquefaction of a part. On the
other hand, when allowed to expand, its temperature
does not, accordii‘ig to them, sink to the lowest that
will support it in the enlarged space, but it becomes
dry or subsaturated steam, unless robbed of some
heat by surrounding bodies, and might even impart
some to them without becoming saturated or cooled
to its dew-point. Thus in escaping into air perfectly
dry or-having‘less than a certain assignable degree of
moisture and of density, it might disperse invisibly
..and form no cloud; which is a thing that could never L

happen on Watt’s supposition if any air, or any fluid
besides steam and. colder than the escaping steam,
were present. Thus if such an escape without form-
ing cloud were ever observed to take place into cold
air, even artificially dried and rarefied, it would dis-
' prove the common theory. But it is very diflicult to
meet with any phenomenon not almost equally con-
sistentwith any of the three. No conclusion can be
drawn from the haze seen in a receiver from which
the air is suddenly pumped out, because we know
nothing as yet of the relative absorptions of heat in
equal expansions of different aeriform bodies, which
absorption may be much greater by air than by steam,
so as to reduce the steam mixed in it to a much
colder temperature than it would reach if expanding
by itself.
On the whole it seems that this most important
question, What rule connects the temperatures or
elasticities or volumes of steam (one or all) with the
expenditures of heat in producing it,—a question
affecting even the resources of nations, remains to be
settled ; and it has been truly said that the imperfect
knowledge of it must still occasion the waste of
more thousands yearly than it would cost pounds to
set it at rest for ever, by a series of the most elaborate
experiments, conducted on the most extensive scale.
To this end, however, a new thermometric scale,
graduated to equal increments of heat, and not of
expansion, seems one indispensable requisite, even
before all else; and more exact determinations of the
specific heats of steam and air, compared to water,
are loudly called for, the discrepancies between the
numbers obtained for these by Orawfurd, Delaroche
and Berard, the authorities commonly followed, being
such as to destroy all confidence in calculations founded
on either. The law of the changes of capacity by
changes of bulk, in aeriform bodies generally, is also
so mixed up in the question, that perhaps no settle-
ment of it can be looked for till that law be clearly
understood, which would require far more experiments
than have yet been made on that subject.
STEAM-ENGINE. The term steam-ea‘az'ae may
bd applied to any contrivance for using, as a source of
continued motion, the force with which water ex—
pands into steam; and a steam-engine is the only
means hitherto found, or at all likely to be found,
for enabling human labour to obtain from inanimate
and naturally motionless bodies, more force or motive
effect than that labour could produce directly; or, in
the words of its inventor, the Marquis of Worces-
ter, “ to make one pound weight to raise an hundred
[or any greater weight than itself] as high as one
pound falleth.” .
Mere machinery, or levers, wheels, and the other
modifiers of motion known as the mee/zaaz'eat powers,
[see ~Sin/ance,] however combined, being only the means
of concentrating or diffusing motion, or converting a
great motion of a small quantity of matter into a small
motion of a larger quantity of matter, and vice oersd,
evidently cannot effect any such increase; and were
never by competent observers expected to do so; in-
asmuch as such, a production of motion without an
STEAM-ENGINE.
095
equivalent expenditure, either of motion itself, or'of
the property of some body to generate it, would in
fact amount to a creation of motion, which must be as
impossible to any creature as the creation of matter.
In order to'obtain more motive effect than can be
produced by his own muscles, man’s most obvious,
and therefore earliest expedient, is the domesticating
of animals, and the contrivance of such machines as
the carriage and the cattle-mill, by which to utilize
the muscular power of such animals. His next, and
probably his true and ultimately universal resource,
is to the perpetual motions of nature, i. e. to those
effects in which either the earth’s rotation, or the
motion of heat from the sun into space, is so resisted
as to have brought together, or concentrated in one
spot, such a portion of their effect, as man may
wholly or partly divert to his own use. Thus, in a
stream, nature has, by the configuration of the valley,
brought together an assignable portion of the sun’s
motive effect in raising vapour from the whole globe,
and concentrated it locally in one line, or even an
assignable part of it in one spot, that of a waterfall,
which is the easiest and first natural mover to be
utilized, by the overshot wheel. In flat countries,
nature, not having produced such a concentration of
power, man has to do it, and he effects his purpose by
means of mill-ponds and the nnclerslzol wheel, which is
evidently a more artificial contrivancethan the over-
snot‘. Tide-mills, driven by the tides flowing into and
out of an excavated reservoir, are a still further re-
finement, made, it is said, by the Romans, but hardly
developed even in our own days. Here the motion
used is a portion of the earth’s rotation, so resisted
oy the moon holding back the waters from wholly
following it, that some motion is continually lost by
their friction upon every shore. Indeed, this friction
must actually retard the rotation from age to age,
and may, possibly, by compensating that acceleration
which astronomers show must accompany the contrac-
tion of the globe by loss of internal heat, account for
the known invariable length of the day since the time
of Hipparchus. Thus, although we are accustomed
to look on the planetary motions in free space as
being efiectcd without friction, this is not the case
with our earth; and so true is it that motion, like
matter, can only be transferred by us and not created,
that the motion which we derive, even from the sun
or the earth, is just so much motion lost to them;
although equally lost whether we apply it or no.
Whether it grinds our corn, or “ on the unnumbered
idle pebbles chafes,” it is so much of the earth’s
original impulse absorbed, as that of a machine is
absorbed in chafing on its axle.
Windmills are a great advance 011 watermills, since
they are not restricted as to locality, and thus are
more artificial, inasmuch as nature has not concen-
trated the motive effect in onenplace, except in the
case of the ridge of a hill which intercepts twice as
many winds as its side. The original motion here, as
in the stream~mill, is that of heat from the sun into
remote space. But it is resisted by, and acts by the
expansion of, air instead of water. Thus every stream’ j

mill is a sun-heated steam-engine, and‘ every wind-
mill a sun-heated air~engine. Of all the natural
utilizable motions, winds are the greatest in amount,
and probably their application is as yet in its infancy,
as well as difierent in method, from what will ulti-
mately prevail. By far the larger portion of the total
wind-power, or that exerted on the watery surface, is
spent not so much in friction as in raising waves,
which, growing throughout their whole course, do in
fact store up all this power (as that of a windmill
might be stored up for future use by pumping water
into a reservoir), and give it out only on breaking upon
an obstacle; so that, on the coast lines, all that wind-
power not available on the land (except what is de-
stroyed in encounters of opposite waves) is concen¥
trated for man’s use, as soon as he can solve the
problem of obtaining equable motion from a motion
so extremely irregular.‘ If waves only lift each par-
ticle of water on the average 1 foot once in 10 se-
conds, this would exceed nearly 100 times the utmost
local effect of tides, viz. 415 feet once in 12 hours;
which will show how greatly this source of power
exceeds that of tides, which is the next in amount.
The total stream-power (which might be reckoned
from the yearly evaporation, and the height of the
centre of gravity of the surface on which rain falls)
would be utterly insignificant compared with even the
tide-power.
But the main source of artificial motion may yet be
that of heat from the earth’s' interior, through deep
borings. Meanwhile, however, there has been induce~
ment, in most civilized countries, to carry out the
Marquis of Worcester’s fine anticipation, (indeed in—
eenlion, for he is now known to have constructed and
used the first steam-engine,) by utilizing the motive
power stored up as it were in a latent form, in those
materials that have been placed within our reach un—
combined, and yet having such chemical affinities as
to combine wit/t force, when once placed in circum~
stances that begin their combination. Properly speak-
ing, there is only one such source of power, the oxygen
of the air. The great majority of natural bodies are
combined with as much oxygen as they can hold, and
such we call inemnbnslidle ,- and so far from containing
any latent power to be thus used, they absorb or
require the application of much power, or of heat,
which is equivalent, before they can be deprived of
this oxygen. But when this is separated, the remain-
ing substance will tend to regain it, and under
favourable circumstances will regain it from the air

(1) What is wanted here is something analogous to \Vorcester’s
“ semi‘omnipotent engine,” which has been unaccountably con-
founded with his steam-engine, although distinctly numbered by
the ingenious Marquis as another one of his “ century,” and bear~
ing no analogy of purpose, or possible application to it;—“an
engine so contrived, that working the primum mobile forward and
backward, upward or downward, circularly or cornerwise, to and
fro, straight upright or downright, yet the intended operation con‘
tinueth and advanceth,» none of the motions above mentioned
hindering, much less stopping the other, but, unanimously and
with harmony agreeing, they all augment and contribute strength
unto the intended work and operation; and therefore I call this
a semi-Omnipotent engine, and do intend that a model thereof be
buried with me.” It was buried indeed, and, if re-invented, will
soorrbury the steam-engine.
696
.STEAM-ENGIN E.
with as much force as was necessary before to sepa-
rate it. If, therefore, nature produce any bodies in
such a state, viz. either void of oxygen, or with less
oxygen than they have attraction for, we have in
them, as in domesticated animals, a store, as it were,
of latent motion or activity, since they will continue
of themselves an action which we only begin or set
going. But of course a certain quantity of them will
only give a certain amount of action, in absorbing the
fixed amount of oxygen with which it can combine,
so that the power is obtained at the expense of the
material, since it is, when combined with oxygen,
spent or consumed so far as regards this property of
yielding motive power.
Such bodies there are, both mineral and vegetable,
and we call them combustibles, and the action of their
union with oxygen, combustion. But it must be
observed that all combustibles do not necessarily
continue this action when once begun: the con-
tinuance of this action depends on whether they tend
to combine with more force or with less force than
is necessary to maintain the circumstances in which
alone they combine at all. The chief of these circum-
stances is commonly a certain high temperature, and
if the action produce not heat enough to maintain
this, it evidently cannot continue of itself; and the
body, although combustible, and contributing to the
heat of a fire in which it is burning, cannot be set on
fire, z'.e. made a fire of alone. Such is iron. But most
combustibles produce in burning far more heat than
is required to light them 5 or, what is equivalent, they
continue the action once begun, not only with force,
but with much spare force for other actions. Such
we call fuels, and they have been burnt in all ages
for the sake of the mere heat yielded, without any
intention of utilizing the motion by which that heat
is diffused and the temporary disturbance of heat-
equilibrium restored; for, indeed, it was impossible
from the appearances about a fire, to conjecture the
enormous amount of this motion. Even the fact of
a large vessel full of water disappearing by this means
does not necessarily lead us to consider the great
height to which all that weight of water has been
raised; and when the same power is expended on the
viewless air, whose weight is made sensible to us
by no common phenomenon, we have no means of
guessing how great a quantity must be moved, and
how far, before the heat evolved from the fuel can be
reduced to equal distribution in the atmosphere. So
little, therefore, does this motive effect strike most
observers, that the first applications of it, as we learn
from Hero, who wrote about 120 15.0., were for the
purposes of magic or priestly imposture.
In his “Pneumatics” are explained several pseudo-
miracles, probably performed by the Egyptian priests
of his time, in which sounds or motions of tangible
objects are made to ensue on the lighting of an altar,
the motion being effected through the medium either
of hot air or steam; and in one of them, steam
generated in a vessel concealed within the altar, was
conducted through the bodies of two statues standing
beside it, and made to press on some wine so as to
l
raise it in a pipe, and make it flow out of two phials
held in their hands; conveying the idea to the unin-
formed multitude that these “dumb idols” assisted
in the libations.
On the revival of learning, many Italians made 01:
described toys on the same principle; such as “fire-
wheels,” “aeolipiles,” &c., which were regarded much
in the same light as those in which motions are now
produced by electricity or electromagnetism, and
probably moved with as little force.
The recognition of the enormous magnitude of the
power so evolved from fuel, the idea of concentrating
for use a great part of it by means of confined steam,
and of substituting it for muscular labour, are, there-
fore, exclusively modern, and originated in the
unfortunate nobleman above named, and, singularly
enough, in the same country—England—that has
since originated every improvement thereof, and
carried the principle to its utmost application. It is
singular, because England was not, in Woreester’s
time, the home either of science or its application,
nor did it contain one philosopher capable of appre-
ciating in the least his wide and far-sighted views.
There is actually no record in the English language
of the existence of his engine; and but for the diary
of Cosmo de Medici’s visit to this country, we should
still be ignorant of the fact that water had, previous
to that period, been pumped by steam, out of the
Thames, at Vauxhall, or that Worcester had ever been
more than the prophet of the steam-engine. After
extreme reverses he wrote, in confinement in the
Tower, his now famous “ Century of the Names and
Scantlings of such Inventions as at present I can call
to mind to have tried and perfected,” and he died in
1656, before physical science was imported by Wren,
Hooke, and Newton, or could be said to exist in
England. His anticipations are remarkable for their
strict limitation to the truly valuable and beneficial
uses of fuel-power, “ not only with little charge to
drain all sorts of mines, and furnish cities with water
though never so high-seated, as well as to keep them
sweet, running through several streets, and so per-
forming the work of scavengers, as Well as furnishing
the inhabitants with suificient Water for their private
occasions, but likewise supply rivers with suflicient
to maintain and make them portable from town to
town, and for the bettering of lands all the way it
runs, with many more advantageous and yet greater
efiects, of profits, admiration, and eonsequenee,—--so
that deservedly I deem this invention to crown my
labours, to reward my expenses, and make my
thoughts acquiesce in the way of further inventions.”
We have then since the time of this great invention,
flzree sources of motion, which have been substituted
for human muscles. The present knowledge of natural
laws does not permit of the conception of a larger
number :—
1. Animals.
2. Perpetual motions.
3. The burning of fuels.
The means of thus applying the last source was not,
by its inventor, nor generally in the last century,
STEAM-ENGINE.
‘697
called the steara-eiz‘rjiae, but 'more ‘properly the fire-
engine. If this name had been retained, we should
not have had to encounter the absurd questions about
“ superseding steam.” Steam is not the agent, but
only the medium or instrument through or by which
it acts, as our will acts by means of muscles which
it has the power of contracting. All that is required
in this medium is materiality and the property of
filling more or less space by the action of the fuel
upon it. Steam, or rather water, is selected simply
from its abundance, and we might as well talk of
superseding earth for embankments, or water for
filling canals, as of superseding water and its vapour
for filling fuel-engines, unless it could be proved that
the only other costless material, air, expands with
more force for the same accession of heat. Enough
has not been settled as to the specific heats of these
bodies to decide this point; but in all probability the
same fuel will produce the same motive efi’ect alto-
gether, whatever the matter it act upon by way of
expansion, whether air, steam, water, or even iron.
But although the expenditure of lzeat or fact for a
given effect would most likely be exactly equal with
each medium, the quantity of medium required to
absorb and carry that heat would differ enormously,
as well as the relation of the velocity to the load
moved. With a solid or even liquid medium, the
motion would be through so small an amount of
space, that it must be immensely enlarged by trans-
mission from short lever arms to long ones, _or from
axles to the rims of wheels, and must require ex-
cessive strength in the first parts, together with
extreme nicety of fit. With air, on the contrary, the
smallness of its difference of pressure with any practi-
cable diiference of heat, would require that it should
act on vast surfaces or pistons, and through a great
space, making the vessels in which it worked un-
wieldy. But a liquid expanding into an air has
immense advantages over a body retaining either
state unchanged. The change of state always involves
a change of bulk far greater than the same change of
temperature would produce on a body retaining even
the aeriform or most expansible state. It seems in-
deed proportional not to the change of seasible but of
total heat, most of which, we have seen, becomes
latent in the aeriform body. [See STEAM.:| Further-
more this absorption of heat'is'itself most advan-
tageous in other ways. It greatly diminishes the
difficulty of retaining the heat where it is wanted,
since only the'seizsitte and not the latent heat tends
to spread and equalize itself. It keeps the whole
machine cooler than it must otherwise be, by the
whole amount rendered latent, which in steam we
have seen to be near 1,000 °, or enough if sensible to
produce a red heat. Lastly, it leads to a most useful
phenomenon, that could never happen with a body
retaining one constant state, such as air. Air ever
so hot and ever so cold, mixed together, would
occupy nearly or quite the same bulk as before the
mixture; but steam coming in contact with such a
quantity of water, colder than itself, that the total
heat of both is insufficient to keep dot/t vaporous, is

suddenly condensed, and the whole becoming water,
occupies some hundreds of' times less space than
when the steam and water were separate, although
their total heat remains the same, which is the reason
why the change may be made so sudden, no time
being required for transfer of heat to or from sur-
rounding bodies.
Again, all these advantages will evidently be
greater, the more heat the liquid absorbs in evapo-
rating, and the more it expands in doing so. Now
it is very remarkable that water greatly excels, in
both these respects, every other known body, even
among artificial chemicals. 1t absorbs, as we have
seen, nearly 1,000° of heat: there is scarcely any
other liquid that absorbs half so much; moreover,
water as steam of atmospheric pressure, occupies
1,700 times its liquid bulk; whereas, no other liquid
is known to expand one-third so much. It may there-
fore be a providential appointment that has made
water the most abundant substance on the surface
of our planet, one so peculiarly adapted to these
mechanical purposes, that in the whole range of our
present knowledge, We know of none other approach-
ing it in fitness for such applications. _
These are strong reasons for supposing that steam
and water must always supersede air, and of course
all costlier materials, as the media for carrying the
power of caloric or fire; and consequently that the
steam-engine will continue to exclude all other kinds
of fire or fuel-engines, and yield only, as it un-
doubtedly must, to such changes in the condition of
mankind, and the distribution of their property, as
may revive the former less centralized use of the
perpetual motions, by stream, wind, tide, and espe-
cially wave-mills, or of central heat; and leave the
fuel, recent or fossil, to its more obvious destina-
tions of warming buildings, cooking, and other
chemical operations.
Worcester’s original steamfoimtaia, as it would
now be called, so far as the accounts of it give mate—
rials for restoration, appears to have been something
like Fig. 2036. The water to be raised was placed
in the boiler B, so as to supply the steam, the pressure
of which drove it up to 1) ; and when B was emptied,
the cock B was shut, and the steam generated in
another vessel 0, to raise its contents, while B was
being refilled. Worcester speaks of so making his
vessels that they were strengthened by the pressure
from within, i.e. their seams tightened, as they would
be if made with internal flanges; and he burst a
piece of ordnance in his preliminary experiments on
their strength. He concluded that the pressure of
the steam was limited only by his power to confine
it, and that however high the lift from B to I), steam
might, provided the vessels were only strong enough
to contain it, be ‘made sufiiciently elastic to press
the water from B or 0 up the ascending tube into the
reservoir :0. He found that one measure of water
was required to be evaporated in B, to drive up 40
measures of cold water, he does not say how big .
Were there no loss, it would be capable, as we have
seen, of driving up 1,700 to the height of the waters
098
STEAM-ENGINE.
column that balances the atmosphere, or 33 feet. The
waste was occasioned by the fire spent in heating not
I?
Fig. 2036, woncns'rsn s STEAM-FOUNTAIN.
only the steam, but the whole of the raised water to
boiling, and it must have been enormous.
The Marquis of Worcester’s small book attracted
some attention on the part of mechanicians, even in
the generation of its author. About twenty years
‘after the death of the author, Sir William Morland
constructed the second steam machinery, with what
improvements on the first we know not. He endea-
voured to draw the attention of the French monarch
to the subject, but does not appear to have met with
encouragement.
About the year 1695, attempts were made in France
by a native, Dr. Papin, the inventor of the safetyevalce,
(without which the steam-engine could not exist,) and
consequently of the hardly less important dz'yester,
which bears his name. [See DIGESTERJ Papin’s first
attempts were with one vessel only, but he soon
found the advantage of separating the steamegenera-
ting vessel, henceforth called the boiler, from that
containing the water to be raised. This did not,
however, obviate the heating of the latter, which con-
densed most of the steam admitted to it, and was
raised nearly to the boiling point. In order to
avoid so much loss from this he afterwards, about
1700, invented the arrangement shown in section,
Fig. 2037. The safety-valve here appears on the
boiler 13, and is, as every one knows, a small cover
or stopper, sitting loosely on or in a small aperture,
but kept down by a certain weight, which is here,
as usual, made to increase its effect by a lever, so
that it may, by being slid along it, like the weight
on a steel-yard, serve without change of weights
to vary the pressure which the steam is allowed to
acquire. This, of course, it cannot exceed without
lifting the valve and escaping, until reduced below
the limit thus allowed it. The valve‘ is simply the
weakest or most yielding part of the boiler, and by

taking care that it shall always ' be the weakest, the
danger of explosion is avoided. Papin’s next im—
provement was a thick or hollow float r, lying on the
water in the vessel 0, and fitting its sides as closely


Fig. 2037. rarm’s STEAM-PUMP on Enema.
as possible, to prevent the contact of the steam
with the cold water, which he had found wasted so
much, although here too a great deal of steam would
be condensed by transferring its heat through the
float. His water—pipe first descended, then ascended,
and had a valve opening upwards only, as at V, while
' a pipe R, bringing the supply from a tank to the
lowest part of the main pipe, had a valve opening
downwards towards the main pipe. The object was,
that when the contents of 0 had all been driven up
through v, it might be refilled by shutting off the
supply of steam at s, and what was thus enclosed in
0 being rapidly condensed into water, an almost entire
vacuum would be left between P and s, so that the
atmospheric pressure on the supply tank would drive
water through the valve n and up to fill 0, even
though it were some feet higher than the original
level of the water. The cock s was then opened,
and a new supply of steam admitted into 0, the effect
of which was to depress the float, and the water under
it, which can only find exit through the valve v, and
not through n, which opens towards it; and when
much water arising from the condensation of steam
was accumulated on 1?, it was let out by the small
cock at the side. The ascending pipe terminated in
a close vessel, in order that the air compressed there
might press the water up through a second ascending
pipe w, with a continuous, instead of an intermitting
stream.
It is uncertain whether the idea of lifting a weight
by the atmospheric pressure against a vacuum, made
by the condensation of steam, (a mode of using its
power quite distinct from Worcester’s,) was original
with Papin, or imitated from the machinery of Capt
Savery, who, about the same time, revived the atten—
tion to steam power in England. Savery’s engine, as
shown in section, Fig. 2038, was secured to him by
patent in 1698, and was the first to be practically
applied for draining mines. The steam is alternately
admitted and shut ofi’ from the steam vessel or re-
eez'oer B, by the cock 0. When first admitted, what-
ever is not condensed in warming it, passes on into
the rising pipe, which it cannot descend, because both
the valves vv’ open upward, but it lifts and escapes
by the upper valve v’, the rattling of which warns the
STEAM-ENGINE.
699
attendant to stop the steam-cock e, and as all air has
been expelled from It, and cannot return through v’,
the gradual cooling and condensation of the steam in
it leaves a partial vacuum, into which water from the
well is driven up through the valve v. When R is
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cold, it is nearly full of water, and the steam being
again admitted through c, presses this water not back
through v, as that valve cannot open downward, but
up the rising pipe. When all is expelled, the cock 0
is again shut, and another called the injection-cools I
is opened, which admits water from the column that
has been raised, (and cannot return through the valve
V’,) to enter, and be dispersed through the steam in
R, from a nozzle N, pierced with holes in all directions.
This shower rapidly condenses all the steam and makes
a new vacuum, into which a fresh receiver-full of
Water from below opens the valve v and ascends,
ready to be expelled upwards by another supply of
steam. As the two cocks, c and I, are never to be
both open, and need never be both shut at once, they
are so connected with a single handle II, that one
motion does all that is necessary to change the action
of the engine, from the sucking up water by the
condensation of the steam, to the driving it up by
the pressure of the steam, and nice oersa’.
Papin, who was a most ingenious but unpractical
mechanician, described other modes of using steam
without the loss entailed by allowing it to touch the
_water to be raised; and certainly he was the first to
propose, although in useless forms, the suspended
piston, moving up and down in a smooth cylinder
exactly fitting it, as in all modern engines. A small
quantity of water in the bottom of this cylinder, being
vapourized by placing fire underneath, drove up the
piston; and on allowing it to cool, and again become
water, the atmospheric pressure brought the piston
down, with a force sufficient to lift, by a cord and
pulleys, a considerable weight. He thus invented
two most important parts of our engine, the safety-
valoe, and the piston.

Both Savory and Papin proposed to apply their.
engines to the production of an artificial waterfall for
driving mills or other machinery, that is, they would
have raised by steam the water of a lower reservoir
into a higher one, in order that, by continually flow-
ing back, in a circuit, it might drive an overshot
water-wheel, from the rotation of which, the motions
for any other mechanical operations are best derived.
This, however, was never done, and Savery’s engine
continued to be employed only in the drainage of
some Cornish and Devonshire mines, until it was
superseded in 1705 by a most happy combination of
the ideas of Savery and Papin: this was the atmo-
sp/zerz'e engine, invented by Newcomen, a smith of
Dartmouth, and patented jointly by Newcomen, an-
other person, and Savery himself. The atmospheric
steam-engine is in fact no more than the practical
and useful form of Papin’s last-named proposal for
raising a weight by the atmosphere pressing down
a piston first lifted by the formation of steam under
it, and then left unsupported in consequence of that
steam being condensed again into water; and the
main addition necessary to make this of practical use,
was simply the separate boiler, for want of which
Papin, having to generate and condense his steam in
the same vessel, lost so much time in the alternate
heating and cooling, that the whole was merely a
curious experiment ; and it is wonderful that so inge-
nious a man, knowing that the idea of separating the-
boiler from the working cylinder had already been
developed by Savery, did not see the necessity of
such separation in order to confer any practical value
on his invention. No sooner was this done by New—
comen than the steam-engine at once took the general
form and properties which it has retained to this day,
insomuch that there is not a change introduced by
him which has not been permanent, nor a single part
or feature of Newcomen’s engine but continues an
essential in all future engines, merely improved in
detail, but identical in name and principle. And this.
be it observed, is what cannot be said of any other
improver, certainly not of the more celebrated Watt,
each of whose amendments was the only successful
one out of a numerous batch of patented contrivances,
many of them most chimerical, and the majority never
heard of again, apparently heaped together like lot-
tery tickets in the mere hope that all might not be
blanks.
Newcomen’s engine, then, in which most of the
parts still essential to be understood, originated and
took their present names, is represented in Fig. 2039,
cut through the axis of the cylinder 0 and the piston
P. The latter is suspended from one end of the
working—beam A A, which is balanced at its centre, on
the wall of the engine-house, and at its other or out-
door end is suspended the rod of the pump, or series
of pumps, by which the mine is drained. This, with
its appurtenances, is commonly so much heavier than
the piston, as to overcome its friction in the cylinder,
and thus quickly draw it up to the top, where it re-
mains when the engine is not in action. Should the
pump-rods alone be not heavy enough for this, they
700
STEAM-EN GINE.“
are loaded with weights w, the amount of which
regulates how quickly the up-stroke of the piston
shall be performed. The piston was bound with
leather, and kept air-and-steam-tight by a little water
lying on it, supplied from the tank '1‘. The cylinder
has no cover, but a flat bottom, so that no steam may
be wasted by occupying space not necessary to sup-
port the piston. Now, when steam is admitted from
the boiler 13 through the steam-cock c, it has to drive
out the air occupying the cylinder. This it does by
the pipe ending in the valve .9, which resembles a
small unloaded safety-valve immersed in water, and is
called the Mow-valve, or snzflz'ng-oaloe, from the pecu-
liar noise made when, the air having all bubbled out,
the steam begins to follow, and instead of escaping in
bubbles, is instantly condensed by the water, with a
kind of decrepitation. This sound, then, being a sign
that the air of the cylinder is all displaced by steam,
the attendant, on hearing it, shuts the cock 0 and

opens another ‘by which water from the cold reservoir
T was, in Newcomen’s first engine, thrown in a shower
over the outside of the cylinder, so as to cool its con-
tents, reduce all steam above the cock 0 to water,
and therefore to about l,looth of its bulk, and thus
leave the piston-unsupported against the atmospheric
pressure of above 141 lbs. per square inch, which of
course quickly brought it to the bottom, lifting, in
the rods and weights w, and the water following
them, any weight less than M times as many pounds
as the area of the piston 1? had square inches. In an
early trial, however, a small leak in the piston allowed
some of the water lying on it to keep it tight, to fall
through into the cylinder when full of steam, and this
produced an instantaneous condensation and descent
of the piston so much faster than usual, that the ,ex-
perimenters at once altered their cold water pipe,
and made it enter the cylinder and throw up a jet
within it, (as shown in the figure,) instead of merely



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Fig. 2039.
washing its exterior, whence the cock 2' (retained, like
all these elementary features, in some shape, to this
day) is called the injection-cools; and thus did they
accidentally discover, and forthwith turn to account,
the third of those properties of steam on which its
mechanical usefulness depends. Worcester had taken
advantage of its expensive force only; Savery, of its
renew] condensation‘ by cold, which creates a further
force‘ by calling into action the pressure of the atmo-
sphere; but it is doubtful whether both these could

NEWCOMEN’S, OR THE ATMOSPHERIC STEAM-ENGINE.
have rendered the steam~engine really useful, but for
Newcomen’s discovery of the insz'anz‘aneonsness of this
condensation when effected by injection, 5. e. by the.
contact of water minutely scattered through, and
moving against, or mixed with the steam, as by a
shower or jet; for it has been remarked that the
steam-engine could hardly exist as a useful power if
the destruction or liquefying of a given quantity of
steam took a time at all approaching that required for
its production- , I '
STEAM-ENGINE.
701
As the large pumps of the mine rarely lift the water
to the surface where the engine stands, but only to
some lower level whence it flows ofi through the edit
to the lowest ground in the neighbourhood, a smaller
pump, worked by the rod IE‘, served to lift, from the
adit level to the tank '1‘, as much water as the engine
itself required; all of it being first used for inj cction;
and then, from the hot water that ran out at each
stroke by the pipe and valve s, consisting of both the
injection-water and condensed steam, a portion equi—
valent to the latter was returned to feed the boiler;
the larger part, however, escaping, and carrying with
it all the heat produced by the fire, except what
might pass up the chimney, or radiate from the hot
surfaces of the furnace, the boiler, and the cylinder.
It will be seen that the analogy with a common
hand—pump is so far preserved, that the whole of the
work is done by the up stroke of the pump rods, or
the descent of the moving power at B; and this
being produced by a force acting within the engine-
house, is called the iii-door stroke. When this was
completed, the attendant closed the cock i, and re—
opened 0, and the piston being now as much or nearly
as much pressed from below by the steam, as from
above by the air, it is free to re-ascend, and is quickly
brought back to the top; which motion being due to
the weight acting outside the engine-house, is hence
called the cat-door stroke, and restores the machinery
to its original and resting position, ready for another
injection, to produce a second in-door or working-
stroke. Thus, although steam be the agent through
which the power of the fuel is exerted, yet it is not
in the generation, but in the destruction of the steam
that its force is here obtained. The filling of the
cylinder with steam does no work directly, but stores
up its effect for future use, by lifting a dead weight,
(viz. the column of air incumbent on the piston,)
whose return by gravity afterwards does the work.
Although rarely seen in use,‘ there is much reason
to think with the Comte Pambour, that with certain
additions (chiefly Watt’s separate condenser and
air-pump, presently to be described) and some con-
trivance for well clothing and retaining heat in the
cylinder, which might possibly be immersed in the
boiler, the atmospheric engine might again become
useful under certain circumstances, especially in new
countries, where the fuel is wood, and its economy
less important than that of metals, and of skilled
labour. For it is certain that no other form of
engine will produce a required power with so little
first cost, so little strength and mass in the con-
struction, or so little dependence either on nice
workmanship or solid foundations; and although we
are accustomed to look on all these as trifles com-
pared with the daily saving of a little fuel, the reverse
still holds good over at least half the world. It is
even conceivable that the atmospheric engine might,
in such countries, reappear in steam navigation ; the
first essays at which were undoubtedly on this prin-

(I) In August 1852, the Editor saw a. Newcomen engine at
work, at a coal and iron pit near Glasgow. See MINE—Minus,
page 272.

ciple, viz. that by our countryman, Jonathan Hulls, in
1736, if not the paradoxically far-sighted, and almost
prophetic attempt of Blasco de Garay, who, in 1543,
a century before Worcester, and before even the
effects of the air’s weight were attributed to weight
at all, is said to have propelled a vessel in Barcelona
harbour, by power evolved from a caldron of boiling
water l
A boy named Humphry Potter having to attend
one of Newcomen’s engines, is said to have relieved
himself of the trouble of turning the two cocks c and
i, Fig. 2039, at each stroke, by so connecting them
by levers and strings with the moving parts of the
engine, as to make it, in finishing each stroke, to
shut one and open the other, and thus itself produce
the next stroke; and this being observed not only to
save attendance, but greatly to add to both the
regularity and speed of working, a more refined
mechanism for the purpose was forthwith contrived,
and was much improved in 1717 by Henry Beighton,
HRS; since which time valve-gear, or the means
by which every stroke of the engine may open and
close, at the proper times, all cocks, valves or passages
necessary to the stroke, has been deemed indispensable
in all engines, and has received greater varieties of
form and elaboration of contrivance than any other
part of the system.
In 1720 a theorist named Leupold proposed a
mode of employing steam power exactly opposite to
Newcomen’s. Retaining the arrangement of open
cylinder and piston suspended from a balance-beam, he
nevertheless abandoned the power obtained from the
condensation, and returned to Worcester’s principle
of employing only the excess of the steam’s pressure
over that of the atmosphere.‘ His boiler, therefore,
required great strength, its whole interior having to
bear as much pressure per square inch as that which
moved the piston; whereas, in Newcomen’s engine,
by raising the steam to no more than the common
boiling point, the boiler might have no tendency either
to burst or collapse, and consequently be made only
strong enough to support its own weight, and yet the
piston be driven by nearly let lbs. per square inch.
Leupold proposed two cylinders to be placed side by
side, (as shown in Fig. 2040,) each working its dis-
tinct beam and pump ; and while steam was admitted
into one cylinder, so as to drive up its piston, the
other was allowed to communicate with the open air,
so that the cylinder-full of steam admitted to it in the
previous stroke might be expelled by the descent of
its piston, and so on alternately. Both pistons, there-
fore, had to preponderate over the weight of their
respective pump-rods, and this sufficiently to overcome
the friction of the whole apparatus, and bring the
pistons to the bottom of their course when out of
action, which is just contrary to Newcomen’s distri-
bution of weight, and plainly far less fitted to mining
purposes, the pump-rods and the water raised by them
being usually by far the heaviest side of the balance,
and requiring a most cumbrous addition to the steam»
piston, if that is to be made to preponderate. More-
over, the transmission of power from the piston to the
702
STEAM-ENGINE.
beam, which in Newcomen’s engine is made by a pail
only, and therefore needs but a chain, (see Fig. 2039,)
is here made by a pas/i, so as to call for a stiff con-



\\
'filimnuifl-i-m
LnuroLn’s PROPOSED STEAM-ENGINE.
nexion called the piston-rod, which, although neces‘
sary, as we shall see, in most of the modern applica-
tions of steam, should not be so in these single-acting
engines, i.e. such as exert their power only in one
direction, and would in this case be very liable to
bend and break. In short, the defects of Leupold’s
contrivance are so great that we cannot wonder at its
never having been put into practice, although it has
always held a place in the history of the steam-engine,
as the supposed progenitor of our present nigh-pres-
sure, or non-condensing engine, to be described here-
after. But in truth, as what is called the “high-
pressure principle,” (or that of employing steam
against air, instead of against vacuum or weaker
steam,) was necessarily the/inst mode of employing it
by Worcester, and as all condensing engines are some-
thing more than this, the mere omission of condensa-
tion cannot, we apprehend, be called a “principle” or
an “invention” at all, any more than the omission of
arches in building, or the abandonment of anything
else as not worth doing, which had previously been
thought worth doing. And if it be said that Leu—
pold’ s was the first non-condensing engine with pistons
&c. interposed between the steam and the water to be
raised, these arrangements were merely taken (or
rather, badly imitated) from Newcomen; nor is there
one feature even original in this proposal, except the
four-way coo/e s, by which one movement is made to
effect all the changes necessary at the beginning of a
new stroke. This cock is a solid cylinder, pierced
with two curved passages, as seen in the figure, and
turning in a hollow cylinder from which four ways
open, to the two cy-
linders, the boiler,
and the open air.
By turning it one
quarter round, or
from one into the
other position shown
in Fig. 2041, it will
be seen that the


a.—




Fig. 2041.
LEUPoLn’s roun-way
coon.

piston previously receiving steam from the boiler, is
left to expel that steam into the air, while the other
piston ceases to communicate with the air and begins
to receive steam from the boiler. Another quarter
turn, in either direction, would restore the former
conditions, so that, by either moving the cock alter-
nately through 90°, or making it constantly revolve,
the two engines are kept at work. Of course, in
this crude form, the grinding of the two cylindrical
surfaces, one within the other, would rapidly wear
them so as to produce leakage; but as this is easily
remedied in two ways, (either by the simple substitu-
tion for the solid cylinder, of a hollow and elastic one,
slit from end to end, so as to expand and press out
against the enclosing case, or by making both parts
conical, and constantly pushing the movable cone as
far as it will go into the fixed one, by a spring, or
weight, or cushion of steam,) there seems no reason
why this part of Leupold‘s engine should not still be
found useful as one of the simplest possible varieties
of valve-gear.
For about 60 years, from 1710 to 17 7 0, the engine
remained almost in the state to which Newcomen had
brought it, although occupying for the latter part of
that time the attention of Smeaton, indisputably the
greatest statical architect of modern times. It is
truly astonishing that a designer so unrivalled in the
mechanism of all fixed structures, fulfilling in them
the newest and boldest requirements in the very
simplest ways, (and moreover so ingenious and con-
elusive an observer and experimenter on the mechanical
powers, including steam itself,) should be employed
on this engine, and even on extending its scale far
beyond any previously attempted, (his largest engine
being of 108 horse-power,) without seeing the great
improvements for which it was now fully ready, but
which were left for Watt to carry into execution. It
seems, however, that even between Statics and Dy~
namics, which are regarded as divisions of the same
science, or at least between the inventive application
of each, Architecture (or Engineering as it has been
called since Smeaton’s time) and Machinery, the con-
nexion is not close enough for the same persons to
excel in both; although it is easily seen that a really
good machine must possess excellences of both kinds,
and that many most ingenious modern ones by Watt
and his successors, are sadly deficient in the statical
element, and hence fall as far short of Smeaton’s
atmospheric engines in economy of material andwear,
as they excel in that of fuel and attendance.
Though all Smeaton’s improvements were, in com-
parison with those of Watt, mere matters of detail,
they affected nearly every part of the engine, and,
not confined to structure and proportions (his true
province as a statical engineer), many effected also
savings of power, heat, or fuel. He first made ex-
periments on the form of boilers, which had hitherto
been mere repetitions of the alchymists’ vessels, either
globular, or large portions of globes with a flat
bottom, and the fire beneath, wasting most of its heat
through the surrounding walls, or by passing up the
chimney. A little consideration led him to the placing
"S TEAMTENGTNE":
‘703
of the fire within, entirely surrounded by the matter to
be heated, and then to the lengthening of the boiler
into a horizontal cylinder, through the whole length of
which the flue might be carried from the fire at one
end to the chimney at the other. This latter im-
provement, however, had not occurred to him when
his largest engines were constructed. They still had
what he termed, from its shape, a hay-stack boiler.
Of course the more we deviate from a globe, (the
figure of greatest capacity with least surface,) the
more material we spend to enclose a given bulk of
contents, and therefore the worse vessel we make for
a storing vessel or reservoir ; but this has nothing to
do with the efficiency of a boiler, which is measured
not by how much it holds, but how much it evaporates
in a given time; and as this depends, cete'ris paribas,
on the number of bubbles of steam that can be form-
ing at once, that is, on the area of surface the water
rests on, and not at all on the quantity of water,
whatever is best for a tank must be worst for a boiler,
and vice versa”. Smeaton found the best proportions
for the length and diameter of the working cylinder
in his largest engines, to be as 3 to 2, his great Chase—
water engine being 6 feet in diameter and 9 feet in
height, a much wider proportion than had previously
been used; although Mr. Francis Blake, F.R.S., had
proved theoretically that the wider and shorter the
cylinder, the better it should be, without limitation
unless from circumstances even yet unobserved; for
while the pressure urging the piston varies as its area,
or the square of its diameter, the friction retarding it
varies only as the circumference, which is as the simple
diameter. In other words a piston four times as large
as another, has only twice its circumference and twice
its friction, so that when driven by the same quantities
of steam per minute, (which they must be if perform-
ing equal numbers of strokes in two cylinders of
equal capacity,) the larger piston will do the most
work, or overcome the greatest resistance ontsiele the
cylinder, when both are made, by levers, &c., to move
that resistance with the same speed, for the actual
speed of the large piston would of course be only a
quarter that of the small one. To this day the limits
of this principle do not seem to have been reached;
for although most cylinders are shorter proportioned
than Smeaton’s, and even shorter than their diameter,
the tendency is still to shorten them. Smeaton was
the first also to reduce the power of engines to an
arithmetical measure. The number by which he de-
noted it, was formed by multiplying together the
number of feet through which the piston travelled in
a minute, the square of its diameter in inches, and
the number of feet of water to which the pressure
driving it was equivalent. Thus, if the condensation
were such as to reduce the steam under the piston to
1800 temperature or half the atmospheric pressure,
which he found was about the best degree, the
pressure acting to depress it was half an atmosphere,
or equivalent to about 17 feet of water. Then if its
speed were 80 feet per minute, and its diameter 20
inches, or area 400 circalai‘ inches, he called the power
of that engine 17 X 80 X dOO, or 544,000. This im-

plied that the maximum of work to be obtained from
it, supposing no friction, would have been lifting a
column of water 20 inches diameter and 17 feet long,
80 feet high, per minute; or a column 1 inch in dia-
meter and 1 foot long, M45000 feet high per minute ;
or 5%,000 such measures 1 foot high per minute.
Now the pressure of a foot of water on a base of 1
circular inch, is, within a very minute fraction, one-
third of a pound avoirdupois, so that Smeaton’s
dynamic unit denoted the power that lifts a third of a
pound 1 foot high per minute. The power of his
largest engine was 7,558,000 of these units.
Smeaton seems also to have introduced the regu-
lator called the cataract, which still determines the
number of strokes to be performed in all single-acting
engines. We have said that the valve-gear, or that
for opening and shutting, by the engine’s own stroke,
the passages of the steam and injection water, had
been greatly improved, the objects being suddenness
and well-timed closing and opening of their full area,
at the moment each stroke ceased. To this end a bar
hanging vertically from some part of the working-
beam, was furnished with certain projections or plays,
that, at the proper moments, touched and moved the
levers acting on the valves, and was from them called
the play-tree. This is now allowed only to act directly
in effecting the changes that stop the .working stroke
of the piston and start its non-effective or up stroke.
The next effective stroke is started by an action brought
about thus :--The plug-tree in its ascent (or which-
ever motion corresponds to the piston’s ascent) draws
up, by a flexible chain or cord, a small plunger or
piston enclosed in a small pump-barrel, standing with
its foot in water, and called the cataract. The foot
has a valve opening inward, through which of course
water is by this action drawn in, as into a boy’s
squirt. It has also a valve opening outward, through
which the same water may be expelled again, but not
by the reversed motion of the plug-tree, because we
have said this has only a flexible connexion with the
plunger, or can pull, but not push it, i. e. raise but
not depress it. The plunger then is left to subside
by its own weight, or some weight with which it is
loaded for the purpose, and only as fast as this weight
can expel the water through the outward-opening
valve. This must plainly always take an exactly
equal time, as long as the weight and the area of that
passage for the water remain constant; and when the
plunger has sunk to a certain point, it (and not the
plug~tree) is made to perform these changes in the
valves that start the engine on its next working
stroke. Thus the time between stroke and stroke
depends solely on the weight with which the cataract
plunger is loaded, supposing its outlet passage un-
varied ; but means are commonly provided for enlarging
or contracting this passage ; and by varying either this
or the weight, the number of strokes to be performed
in a given time can be regulated, and will remain un-
changeable, and out of the power either of atten—
dants or variations in the fire to affect. Steam may
be generated faster or slower, but it will only, in one
case, accumulate to a higher pressure, in the other
"7 04
@STEAM- ENGINE.
sink to a progressively lower pressure in the boiler;
and though the working stroke be performed in a
shorter or longer time accordingly, yet the number of
strokes in a minute, and consequently the work done,
and the quantity of steam and of heat expended, cannot
‘vary, as long as the engine is working at all. Thus
the attendant’s whole task is reduced to keeping the
boiler steam at a constant pressure.
In 1'7 61 ~ commenced the labours of that great
philosopher and inventor, whose name must always
be identified with the steam-engine, as the settler of
its theory, the first who learnt to reason accurately on
it, and therefore the completer of its economical
reform, leaving henceforth only a moderate margin
for the saving of fuel, establishing the principles on
which all future improvements must be founded, and
reducing all possible progress henceforth to matters
comparatively of detail. Watt’s first experiments,
indeed, were unimportant, and it seems he did not
recur to the subject, until required, in 17%, to repair
(his business being that of a philosophical instrument
maker) a small model of an atmospheric engine be—
longing to the University of Glasgow. The cylinder
of this model was 2 inches in diameter, and 6 inches
in length. His investigations into the causes of the
failure of this miniature engine to imitate the work-
ing of large engines, led him gradually to a better
=understanding of the requirements of such engines in
general, than any one else, even Smeaton himself, had
yet realized; and after a series of experiments on the
relation between the temperatures and pressures of
vapour, (which were the first to show that fixed con~
nexion between them which we have explained under
STEAM, where the'results of these his measures will
be found,) and after other experiments on the expan-
sion of water in evaporating, which he estimated at
1,800 times, under the common pressure; and also on
the time occupied or the surface necessary to evapo—
‘rate a given quantity; and especially on the quantities
'of steam and injection water to be mixed for effecting
a given reduction of temperature and pressure; he
satisfied himself of these two points as most impor-
tant to be aimed at in engine making: first, that the
cylinder ought, instead of being alternately heated
and cooled, to be kept if possible constantly as hot
as the steam that enters it; and secondly, that not-
withstanding this, the quantity and coldness of the
injection water should be such as to form with the
condensed steam a mixture not hotter than about
100°, so as to leave the vapour not more elastic than
saturated steam of 100°, which we have seen sup-
ports about 1'8 inch of mercury. Smeaton, as already
stated, cooled it hardly lower than 180°, at which
temperature it supports 15 inches, and thus he lost
‘half the atmospheric pressure, for the sake of avoid-
ing the great waste of incoming steam that the sides
of the cylinder would condense before the next stroke
‘could begin, had the cylinder been allowed to become
cold enough to produce a more perfect vacuum.
If a reader, ignorant of the steam-engine except
from these pages, will now, with quite as much know-
:ledge of steam and its properties as Watt had at
action of the engine.

the time to which we are now referring, endeavour to
suggest how these two requirements are to be recon-
ciled, he will appreciate the ingenuity and beauty of
Watt’s solution of the difficult problem, which, he
says, occurred to him one day early in 17 65, and
afforded such a clue to the whole labyrinth of engine
reform, that, in a few days more, the whole series of
improvements which he afterwards carried out, had, in
their principles at least, sprung up and become settled
in his mind. His primary idea, on which the whole
structure of the modern engine depended, was, that if
instead of cooling the cylinder-full of steam by an in-
jection of cold water, a‘ communication were to be
opened therefrom into anal/ter vessel, cold, void of air,
andin which a ct or shower of cold water was difi'used,
the steam would instantly rush into this vacuous
vessel, where, as fast as it arrived, it would be cooled,
liquefied, or killed and got rid of, and thus the cylin-
der would be rapidly emptied wit/zeal necessarily being
coolecl a single degree, its whole vapour being reduced
to the clensz'lg and elasticity of that in the cold con-
densing vessel, although remaining as not as may be
desired ; and thus the piston being depressed by almost
the whole atmospheric pressure instead of half, it
could nevertheless be immediately driven up again on
admission of fresh steam, the cylinder having hardly
lost any heat, and therefore hardly wasting by con-
densation any of the incoming steam. But, turning
now to the other vessel which we call the condenser,
although it is evident that one much smaller than the
cylinder would suffice to receive and condense all its
contents, or ensure one stroke, yet it is equally clear
that, as every stroke brings both more injection water,
more steam water, and more heat into this receptacle,
it cannot long retain, however large, either the vacuity
or the coolness, which are the two essentials to the
due performance of its functions; but must become
at once more full of water, more hot, and because
hotter, full of vapour of a continually higher density
and pressure, until by approaching the pressure of
that supplied to the cylinder, it would stop the whole
Now the accumulation of heat,
and therefore of elastic vapour, can be stopped by
immersing this vessel in a running stream, or a tank
artificially supplied with a continual influx of cold
‘water, (as the tank that supplied the injection
water always had been in Newcomen’s engine, Fig.
2039,) provided only we could get rid of the hot
water from within the condenser, as fast as it is
formed there by the union of the injection water
and steam. Watt’s first idea for efiecting this
object, although never carried out, was simple and
ingenious. A pipe was to descend from the bot-
tom of the condenser, and ,dip into some large store
of water 341 feet below it. From 32 to 341 feet of
this pipe (more or less according to the weather)
would always be full of water, supported by the
atmospheric pressure on the water below, and forming
in fact a water barometer, while the condenser itself
would remain void of liquid notwithstanding all that
enters it, which would flow away down this pipe,
never accumulating higher than the column which
sqI-EaMnNeIN-B.
705
the atmosphere could support at the time. The ob-
jection to this is, that as all ordinary water contains
air and gases which escape from it when either heated
or relieved of the common pressure, both the steam
and injection—water must constantly bring some air
with them into the condenser, the former being mixed
with what the boiler-water gives out in being heated,
and the latter giving out its own air as soon as it
enters the vacuoils condenser; which vessel, therefore,
and consequently the cylinder communicating with it,
would soon contain air elastic enough to resist the
whole atmospheric pressure that works the engine.
Foreseeing this, Watt next devised a pump to be
worked by some part of the beam of the engine, and
so contrived as to draw out of the condenser, at each
returning or up-stroke, whatever air had accumulated
there by the preceding condensation. In order to
estimate its quantity, we must remember that the
cylinder-full of steam, if exactly of the atmospheric
pressure, or at the temperature of 212°, will occupy
as water filfith of the capacity of the cylinder, but
being usually of a somewhat higher pressure and den-
sity, we will assume it to occupy filwth. If thein-
jection-water be 7 times this amount, which is a usual
proportion, both together will equal TL,fioths or ,goth
of the cylinder. Now the air released from any water
rarely exceeds its own bulk, so that the water and air
together (for if a pump be required at all, it may as
well remove both) will be no more than 713th of a
cylinder-full, under the common pressure. The un-
condensed vapour also, if the condenser be not much
above the temperature of 100°, will be no more than
would fill itself and the cylinder under a pressure of
2 inches of mercury, or no more than {3th of their
joint capacity under the common pressure. Thus we
see how small a portion of the power of the engine
need be absorbed in working this pump, for the whole
power of any atmospheric engine is evidently just
what would work, with its own speed, an air-pump of
its own capacity, supposed to work without friction.
It is equivalent to removing, at each stroke, its own
cylinder-full of matter, against the common atmo-
spheric pressure. Watt conjectured, therefore, and
rightly, that to perform about a 15th of this work,
would be a sacrifice well worth making in order to
avoid the enormous waste of steam which in New-
comen’s engines was condensed in heating afresh, after
every stroke, the whole cylinder just cooled by the
previous condensation; and the waste of power in—
curred by leaving, as Smeaton did, the steam only
half-condensed, in order to avoid cooling the cylinder
more than about 30°, thus leaving it elastic enough
to counteract half the atmospheric pressure.
This the first of Watt’s deductions from his study
of steam, would alone have made the greatest advance
ever made in increasing the efficiency of fuel. It
alone would have enabled one pound of coal to do
that which had previously required 3 or 4: pounds.
But his circumstances, which prevented him for some
years from carrying his ideas into practice, led to the
development in his mind of many more improve-
ments, so that the form of engine which would have
VOL. I l.


resulted from this one alone, the atmospheric engine
with a separate condenser and an air-pump, has never
been executed, and thus leaves a hiatus in the regular
progress of this great invention, otherwise so steady
and gradual. Pursuing his principle of keeping the
cylinder as equally hot and with as little dissipation
of heat as possible, it next occurred to him that the
water placed on the piston of Newcomen’s engine,
and the cylinder-full of external air descending into
it at every depression of the piston, must greatly
cool (and the former also wet) its interior, and lead to
a condensation of the next incoming steam. The
water used for the purpose of keeping the piston
tight was therefore to be replaced by “ oils, wax,
resinous bodies, fat of animals,” (eventually the only
expedient used,) “ quicksilver, or other metals in
their fluid state,” as the specification of his first
patent cautiously provides. The cooling by the air
itself that drives the piston, was not so easily reme-
died; and while his solution of this difficulty involved
such entire changes as to make the whole a new
engine on new principles, and to affect its whole future
history, we believe it was not the only possible solu-
tion, nor eventually to be, as at present, the only
one practised. It occurred to him that as the hot
steam in the boiler ‘exerts as much or even more
pressure than the atmosphere, the top of the cylinder,
instead of being open to the atmosphere, might be
made open to the hotter only; that a portion of the
necessary store of steam would thus do the work
done by cold air in the old engine, and yet no more
steam would be used on this account, because the
same cylinder-ful that had done this work of de—
pressing the piston, would afterwards be introduced
under it, to be condensed and leave the vacuum
against which the next cylinder-full would act.
This of course involved a tight covering to the
mouth of the cylinder, with some contrivance for
letting the piston-rod pass, without leakage, through
its centre. But Sir Samuel Morland, the next ex~
perimenter after Worcester, had, in the previous
century, invented the stufiiug-horc for such cases, a
very simple and hardly improvable contrivance, not
required indeed before this idea of Watt’s, but with-
out which the modern steam-engine could not exist.
It simply reverses the elastic packing of pistons.
They carry, in a cavity all round them, elastic matter
to press outwards against the enclosing fixed walls.
The stuffing-box is a similar cavity in the passage
made for the rod, holding elastic matter to press iu~
wards and clasp it round; and both alike have their
want .of contact made good by means of grease.
It was this great change, rendering the engine
independent of any form of matter but steam to press
the piston, that led to the present name steam-engine,
being used to distinguish Watt’s engine from New-
comen’s as improved by Smeaton; and the term
atmospheric engine on the other hand to distinguish
the old from the new; while the former name, fire-
eugiue, equally and correctly applicable to both,
forthwith went out of use, as already noticed.
Yet another cause of unnecessary cooling, the ex‘
z z
706
STEAM-ENGINE.
posure of the exterior of the cylinder, Watt proposed
to meet by surrounding it with a bath of steam
enclosed in an outer case, communicating with the
boiler, and now called the jacket; for although it
might seem that this. would enlarge the surface for
cooling, and so dissipate more heat, yet he rightly
anticipated that any condensation into moisture wit/ain
the cylinder caused so much less of power as well as
of heat, that its avoidance was worth the incurring
of a much larger amount of condensation elsewhere,
as in the jacket, where it would be simply a loss of
heat.
All these improvements—which together have
quadrupled the effect previously obtained from any
quantity of fuel—were settled in Watt’s mind, as he
said, within two days after the key to them, the
separate condenser, had pointed out to him the way,
and before trying his first crude experiment, in which
a syringe of 1 fi- inch diameter was his working cylinder.
A large model with all these parts, and awooden case
for the purpose of better confining the heat of the
jacket, was next made, but although perfectly demon-
strating his success, he was unable to get these
splendid innovations noticed until the year 1769, the
date of his first patent. This patent embraces, in
addition to the above improvements, a proposal to
revive “in cases where cold water cannot be had in
plenty,” Leupold’s plan of using only the excess of
the steam’s pressure over the air’s, and discharging it
Without condensation; and also a “rotary engine”
to make steam produce directly the circular motion
required for most machinery, and supersede the
pumping up water into a reservoir to drive a water-
wheel by its descent, which Smeaton not only thought
necessary, but even 12 years after this, defended by
a doubt that any “motion communicated from the
reciprocating beam of an engine could ever act with
perfect equality and steadiness in producing a circular
motion.” This rotary scheme, however, like many
others since patented, was a failure, and probably
taught Watt (as it would be well if it had taught
others) the really trifling importance of a problem on
which more mechanical ingenuity, as well as money,
seems to have been utterly wasted in the last half
century alone than has gone to the whole development
of the present steam-engine and its utmost comple-
ment of appendages and refinements.
The single-acting or pumping engine may be said to
have been completed in all its essentials, by this first
of VVatt’s patents, although it is new never made
without borrowing from his later contrivances some
refinements not strictly necessary to it, and a very
few due to other improvers. His next patent, how-
ever, in 1782, introduced another great and new
principle, second only to the former in importance,
and perhaps excelling it in the saving of fuel which
it may ultimately bring about; for although not even
now pushed to its practicable limits, it has in some
cases been carried to the point of making one pound
do the same amount of work that required three
pounds in Watt’s original engines, or 12 lbs. in
Ncwcomcn’s. This, which hardly affects the construc-

tion of the engine, being rather a new principle of
operating than of engine making, is called working
expansioelg, and consists simply in cutting off the
supply of steam from the boiler to the cylinder, when
the latter has been only partly filled, or the piston
partly depressed, instead of leaving this communica-
tion open until the stroke is finishing. The portion
of steam thus shut into the cylinder and left to itself,
will evidently still drive the piston, only with less and
less force as it expands and becomes less elastic, and
would continue to do so, until reduced to the rarity
of the vapour below the piston, which alone resists
it, and which is only as elastic as that in the con-
denser, cooled to about 100°, or about 15 or 16 times
less elastic than boiling steam. Long before this
attainment of equilibrium, however, the piston comes
to the end of its stroke, and it is evident that the
work done must be a greater fraction of what the
same stroke would have done on the old plan, than
the steam used is a fraction of the whole cylinder-
ful. For, suppose we use only a third of a cylinder—
ful of steam. It will, relate entering, drive the
piston one third down, and perform a third of the
work done by a whole cylinder ful on the old plan.
But after this, white expanding, it will exert a power,
continually diminishing indeed, but the whole of
which is added to the above, and is therefore a clear
gain on what ‘the same quantity would have done by
the old method. It has been proved by mathemati‘
cians since Watt’s time, first by Mr. Davies Gilbert,
that the saving possible by this expansive working is
even more important than he seems to have been
aware of. If the work done by any quantity of
steam while entering the cylinder, or without expand-
ing, be called 1, and it be then allowed to expand to
any number of times its original bulk, then the
quantity known as the hyperbolic logarithm of that
number, will express the whole work done when it
has expanded to that extent. For instance,
The hyperbolic logarithm of 2 is 1'69
of s is 2~10
of 4 is 239
of 5 is 2'61
of 6 is 2 79
of 7 is 295
Msnsm
We give these numbers because the discovery of them
by calculation is too complex to be here explained.
Now if we stop the entry of steam when it has half
filled the cylinder, and allow it to fill the rest by
expansion, as its expansion is into twice its bulk, the
whole work done will be the hyperbolic logarithm of
2, that is 169 times what the same steam would have
done without expansion; so that although a stroke
thus performed evidently cannot effect what a stroke
on the old plan would have done, yet two strokes of
this kind (using the same steam as one non-expansive
stroke) will do 69 hundredths more work than that
did. And if, as in some Cornish engines, only an
eighth of the cylinder-full be admitted, so that in eight
strokes only a cylinder-full will be used, this will do
308 times the work it would have done if all had
been admitted to perform one stroke; thus saving,
STEAM-ENGINE.
707
as compared with a non-expansive engine, full two-
lhirds of the fuel.
This will enable us to explain the difference of
Watt’s two modes of estimating and comparing
engines, by the power and by the duty, which it is
very important not to confound. The power means
the quantity of work which an engine can effect in a
given time. The duty means the quantity which it
can effect by a given expenditure (y’fael. The unit of
time, for comparison of powers, is a minute. The unit
of fuel, for comparison of duties, has hitherto been
a bushel 0]“ coals ,- although no authority has decided
what kind of coal, nor how many pounds of it shall
he called a bushel, two points quite necessary to
settle before the duties of engines can be truly com-
pared. For both purposes, the unit of work done is
a pound weight raised a foot high 5 and as Watt
found reason to think, that the strongest horse is
about equal to doing 33,000 times this work in a
minute, he took this power (the lifting 33,000 lbs.
one foot per minute) as a more convenient unit of
power, to be called 1 horse-power; which it will be
seen is equal to 99,000 of Smeaton’s units. Thus,
Smcaton having expressed the power of his Chase-
water Engine by 7,558,000, dividing this by 99,000
gives a little above 77 11.1’. on Watt’s scale.
The power of an atmospheric engine was therefore
simply proportional to its capacity of cylinder. For
the portion of the whole aerial pressure not resisted
by the cooled vapour was always a fixed proportion,
(usually one half,) and it could never exceed what
a perfect vacuum would give, (or double the usual
power,) becoming then unalterable as long as the
size of cylinder was unaltered. The power of
Watt’s or all later engines, however, can be in-
creased without change of size, simply by increas-
ing the pressure of steam, which of course, if the
load remain the same, increases the speed of the
piston, and so the number of strokes, and therefore
the work done in a minute; and there is no limit to
the power obtainable from the smallest cylinder by thus
increasing the supply, provided only aboiler be found
large enough to evaporate the increased quantity of
water, and strong enough to resist the increased
bursting pressure. Thus no particular size of cylinder
or engine can now be reckoned as having this or that
particular power, the power being now dependent,
not on their size, but on their strength, i. e. the
maximum pressure of steam to be safely borne by
them. On the other hand, a boiler may and must
have its power exactly defined, and depending wholly
on size, (of evaporating surface,) and not on strength
at all; for it is proportional only to the weight of
water evaporated, or of steam produced per minute,
and is no way affected by the density or pressure of
the steam; the same weight of high-pressure steam
driving a small piston, or of low-pressure steam
driving a large one with equal effect. Thus a given
number of horse-powers exact no particular size of
engine, but an unalterable size of boiler,- and this may
be ever so strong or so weak, but the stronger it is,
the smaller may the cylinder and machinery be, and

nice oersa’; its strength exactly defining both their
minimum strength and minimum size. But as certain
difficulties in the making and rivetting of the iron
boilers now used, practically confine their strength to
certain rather narrow limits, (for they cannot be
thicker than g ths, nor thinner than -§-ths of an incln)
this in fact determines limits for the size of an engine
of given power, or the power of one of given size.
Now as power has no reference to the goodness of
an engine, or the economy or waste with which it is
worked; so neither has data any reference to time,
or to the size and power of an engine. The smallest
engine, that must work a month to fill a certain re-
servoir with water; and the largest, that will fill it in
an hour, may be conceived to be just equal in point
of duty; and they will be so if the small one have
consumed no more fuel in this month than the large
one consumed in the hour. This cannot be the case,
however, with engines equally good, because there
must unavoidably be more of the power of the small
engine, than of that of the large one absorbed in
friction, as well as more of its heat dissipated by
radiation. We have seen that a piston having
41 times the surface of another, has only twice its
friction; and a cylinder or boiler having 8 times the
capacity of another, has evidently only 41 times its
surface to radiate heat. So that large engines
will always do somewhat more duty, i. e. more work
with a given quantity of fuel.
this reason, any work is done more cheaply in a given
time by one engine than by two or more equally
perfect engines.
The reader will now see, that by Watt’s principle
of eapansii'e working, the power and the duty of an
engine must be oppositely affected. When one is
increased, the other must be diminished. The utmost
power is obtained from any given size of cylinder and
pressure of steam, when it is worked without any
expansion, but in such case the duty is least. By
expansion to such an extent that the steam shall be
admitted for only one-eighth of each stroke, the con-
sumption of steam and therefore of fuel per stro/re is
diminished 8 times, or as 8 to 1, but the eject of the
stroke is only diminished as 8 to 3'08. In this latter
proportion is the power of the engine diminished;
that is, it can perform in a minute hardly three-
eighths of the work that it would have done with ,
steam of the same pressure not expanded. But it
will do with a given quantity offael 308 times the
work that could, by the non-expansive method, be
performed with the same quantity; and therefore its
data is said to be more than tripled. Now if it were
required to preserve this duty, and yet do as much
work per minute as before, i. e. to have as economical
an engine as this expansive one, and yet as powerful
as it was when used without expansion, this would
only be possible with a cylinder more capacious as 8
to 308, supposing the steam in the boiler to be
unaltered; or if the same cylinder were retained, the
steam must be more elastic in the same proportion,
so that either a larger engine or a stronger boiler is
necessary if the same work is to be performed in as
And of course, for‘
z 7. 2
.708
STEAMEN GINE.
short a time and yet more cheaply. Thus although a
given power exacts only a definite size of boiler, and
not any particular strength thereof, nor size of engine,
yet every increase in either of these enables the engine
to be worked to that or any smaller given power
more economically, that is with a higher duty, because
with more expansion. Hence the greatest duty or
economy has been attained in the Cornish mining
engines; which, of all others, are the most costly in
construction, and largest in proportion to the power
exerted, because using the highest pressure of steam
in the boiler, but the lowest in the cylinder, and
therefore requiring the strongest boilers, largest
cylinders and machinery, and slowest motions. In
these too the economy is greater, the more below their
maximum power they are working, and therefore
greatest when they are first erected, and continually
growing less as the mines deepen and their work
becomes increased. And this compensation between
power and duty, or between the first cost of engines
and their economy of fuel is inherent in the nature of
steam, so that, other things being equal, the cheaper
an engine be made, the more fuel must it continually
consume.
Besides this principle of expansive working, Watt’s
second patent introduced the first successful applica-
tion of steam to the production of rotary or uninter-
rupted motion, whence all other motions likely to be
required may be derived. Papin, and many since
him, had suggested or tried means for this, either by
the direct action of the steam on some kind of wheel
(which Watt himself was attempting at the time of
his first patent, but had abandoned) or by arranging
two common pistons to act alternately on a wheel or
axle, each pulling it round while the other was being
drawn back to its starting place by a weight discon-
nected with the revolving parts. Hitherto the means
of doing this had been too circuitous, and it first
occurred to Watt that the most ancient and common
contrivance for getting continuous motion from an
' intermittent power,
the turner’s or knife-
grinder’s foot-lat/ze,

solution of the pro-
_ ‘ blem. The axle of a
heavy wheel is bent
intp a crank, from
which hangs a rod or
cord down to 'the
treadle, which (just
like the indoor half
of the beam of New-
comen’s or any single-
aeting engine) is al-
ternately depressed
through a small are
by the motive power, and then left to ascend by the
‘action of a weight, in this case attached to the wheel
on the side diametrically opposite to the projection
of the crank, as shown in Fig. 20412, but tending, like
the weight at the outdoor end of the engine beam, to
Fig. 2042.
offered the very best-

draw up that which the motive power depresses.
The crank and wheel are pulled round half a turn by
the excess of the motive power over this weight,
which is thus brought to its highest point, and then
its descent carries them round the. other half turn;
and not back by the way they came, because the
momentum acquired by the revolving parts, especially
the rim of the wheel, carries them past the points
where the weight is at the top or bottom of its circle,
or‘ where it has no tendency to turn them either
way.
It is evident that such a wheel, weight, and cranked
axle, placed over Newcomen’s open cylinder, might
be kept revolving by a rod or chain from the centre
of the piston, pulling them half round, as the piston
is depressed by the air, like the lathe treadle by the
foot. But Watt, by closing the top of the cylinder
with a lid and stuffing-box, had prevented this by
constraining the piston-rod always to keep upright
and to move in one vertical line. Its top might
indeed be jointed to another rod or a chain of some
length whose top would be free to follow the circle
described by the crank, but this would raise the
latter to an excessive height. It was easier to retain
Newcomen’s beam, and let the crank rod or chain
descend from its out-door end to an axle situated
below it, or about level with the cylinder‘,——and pull
the crank round its npzoarcl half-turn, while a weight
on the same radius as itself would carry it round the
other half: But the weighted wheel on a large scale
being oumbrous, Watt first thought that it might be
possible to dispense with at least the one-sided weight,
if not the whole wheel, by having two, or still better
three engines acting on as many different cranks
formed on the same axle, but in opposite directions
if there were two, or in directions 120° apart if there
were three; the advantage of three being that each
engine would begin to act before the preceding one had
ceased, instead of at the precise moment of its ceasing.
But he finally abandoned all these plans in favour of
the capital conception of a clonble’actz'ng cylinder,
that is, a method of so using a single cylinder as to
make it serve the purpose of two acting alternately,
the piston not simply returning passively to the end
at which its working stroke begun, in order to be
. ready for another, but being driven back precisely as
it was driven forward, so that both up and down
strokes may be equally effective, and not a moment
pass in which the steam is not working, whereas in
the single-acting engine it can never be working more
than half the time.
To explain the changes necessary in the valves for
this purpose, Fig. 2043 shows their arrangement for
the single-acting engine. There are three principal
valves which are opened independently of each other
by raising their respective spindles s, Q, and x, which
pass up through stuffing-boxes, and are either drawn
and kept up by weights, except when depressed by
the valve-gear of the engine, or else they are kept
down by their own weight, except when the valve~gear
lifts them. In any case, whenever the steam-valve,
the rod of which is shown at s, is open, as in the
STE AM-EN GINE“.
709'
figure, there is access from B‘, or from the boiler'to
the top of the cylinder; the valve, whose rod appears
at Q, is shut, but that at X open. Under these cir-
cumstances, during the first stroke, the air of the
cylinder is expelled through the condenser v and the




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Fig. 2043. STEAM WORKING PARTS OF wn'r'r’s SINGLE-
ACTING ENGIN E.
blow-valve z ; after which, during any other stroke,
the steam under the piston is exhausted into the con-
denser, ’and a vacuum, z'. e. vapour, as rare as that of
the cool condenser, is left at o, for the pressure above
the piston to act against with full effect. When this has
descended a certain portion of its stroke, which por-
tion is said to be performed wz'flifall steam, the steam-
valve 5 is shut, and the steam already admitted ex-
pands so as to drive the piston the rest of its course;
and when it is very near the bottom, the exhaustion-
valve X is shut, and then the valve Q, is opened. This
puts the two ends of the cylinder in communication
with each other, and thereby equalizes the pressure
on both sides of the piston, whence it is called the
equilibrium valve. The piston is then simply drawn
up by the counterweight, the cylinder-ful of steam
passing from above to below it; and immediately at,
or rather before reaching the top, Q is again shut, so
that a little steam shut in above the piston may act
as a cushion to prevent its violently striking the top
of the cylinder, and then the steam and exhaustion-
valves s and X, simultaneously *opened to produce
another down-stroke.
cylinder, instead of requiring a foundation to stand
on, has to be firmly kept down by beams across its
top.
The remaining apparatus, namely that for dis- '
posing of the spent steam, consists of the cold-water
cistern, in‘which the condenser V is immersed; the
injection-cock, which is opened or closed by the rod I,
and may either be open during the whole working
or only during the effective stroke (the amount in-
jected to produce a given degree of vacuity being
It will thus be seen that the ,

rather less in the latter case); and three pumps, A,
w, and F, worked by the beam of the engine. W is
the oolcZ-waz‘erpamp, by which all the water used is
raised from a well and poured into the cistern, whence
some may overflow to prevent it from becoming too
hot, and the rest is admitted by the jet into the con-
denser. A is the air-pump, usually equal ‘in capacity
to the condenser, from which it is to remove at each
stroke the mixed contents of air, water, and low-
pressure vapour that would otherwise accumulate
therein. In the passage, from the foot of the con-
denser into that of this pump, a valve is seen, opening
towards the latter. Two other valves open upwards
through the pump piston, and another valve from the
top of the pump into the small reservoir-H. WVhile
the pump piston is being raised, the air and water
above it are expelled into H, the valves of the piston
itself being kept shut by the pressure 011 them, and
a vacuum, A, is left under it, so that however rare the
contents of the condenser, they open the lower valve,
and half of them pass into A by the time the piston is
at the top. The piston then descends, and the fluids
beneath it, being compressed, instantly shut this
valve, and, being unable to return through it, must
soon become by compression sufliciently elastic to
raise the valves of the piston, as shown in the figure,
and, by the time the piston has descended to the
bottom, the fluids pass wholly above it; Where, on its
return upward, they are compressed between its
valves and the lid of the pump until they are sufli-s
ciently elastic to open, against the atmosphere, the
valve leading into H, and so escape, the air and vapour
into the open air, and the hot water to accumulate in
H, which is hence called the 720! well. From this, as
much of it as was due to the condensed steam, usually
about an eighth, is drawn by the third and smallest
pump 1?‘, to supply the boiler, whence this pump is
called the feed-pump. The remainder of the fluid that
enters H, namely as much hot water as :was injected
cold into v, overflows in waste 5 we say, in waste, be-
cause it carries away all the heat that was communi-
cated, in the boiler, to that 7th or 8th part of it which,
as steam, was directly employed ‘in working the en-
gine. The diffusion of this heat from a certain quantity
of aqueous matter to about 8 times that quantity, is
the source of all the motion- which the engine has
imparted. In diffusing itself from the waste water to
still more matter, it will produce still more motion ;—-
-and it would have produced as ‘ much motion alto-
gether, on air or ‘smoke or other matter, had the
same fuel been simply burnt away in an open fire.
So much fuel burnt produces so much heat; and this,
in spreading through so much matter, produces so
much motion. The steam-engine does but collect
and utilize a part of this motion.1

(1) It must be remembered that however much of the motion be
utilized, all the heat remains either in the waste water or in the waste
steam; all the quantity, only diminished in intensity. It can
therefore, in any purpose to which it is still applicable, whether
chemical or physiological, do all the work that it could have done
before passing through the engine. The diffusion of heat through
more matter does not render it capable of doing less, in total
quantity, but only of doing fewer kinds of work. Every kind of
work done by heat exacts indeed a certain intensity thereof, and
710
STEAM—ENGINE.
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Now, in the'double-acting method of using the same
cylinder, Watt’s object was to make the up-stroke an
exact counterpart of the other, so that as the piston
has been driven down by the pressure of steam above
it against the almost powerless vapour of the con-
denser (or what is commonly called the vacuum) below
it; so an exact reversal of this, access from the boiler
to below it, and to the condenser from above it, may
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drive it up with exactly equal force. Fig. 20414.1 shows
one of his methods of making valves to do this, and
also the remaining parts of his double-acting en-
gine, except the beam to which the various rods are
attached above, and the boiler which, being usually in
a separate building, need not be represented, but must
be imagined to supply the main steam-pipe a. This
terminates in the side of an upright cylinder b b,





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Fig. 2044. womrme PARTS or wn'r'r’s DOUBLE ACTING ENGINE.
longer, but much smaller than the working cylinder,
into which it has two passages ee, called the top and
bottom ports, and its toot communicates freely by a7
into the condenser e‘. This vessel, b b, called the steam-
cbest, encloses a shorter tube 00 of about half its own
area, open at both ends, but enlarged at both, so as
to fit by the aid of elastic stuflings the interior of the
chest, in which it is raised and depressed through a
small space by a rod passing out through a stuffing



- mixed in the air.
,ww .. . .
,involves a certain difi‘usion into more matter, yet no more than
might leave it still intense enough to be applied to some other
kind of work. Thus the heat from almost any kind of burning
fuel has, at the moment of its evolution, an intensity beyond all
our present means of measurement, and would be capable of
doing anything we require, even to the melting of platinum, if
we could only catch it soon enough.' This is the only reason why
we get more heat by combustion in pure oxygen than in air, viz. ,
that we catch it before it spreads through the nitrogen which is
Now, let it once spread beyond its native atoms
far enough to have only the intensity which we call 3,000", it can
no longer melt any platinum, but it can melt just as much iron as
before. Let it spread until reduced to the intensity indicated by
the expression 2,000°, and although it can melt no iron, it can
still mlélt as much brass as ever. Let it pervade twice this matter,
or sink to the intensity 1,000°, it will melt no brass, but it will
melt as much zinc as ever. Again, diffused through twice this
mass, or reduced to heat of 500°, it will not melt zinc, or lead,
but it will distil as much palm-oil as ever. Shared by more, until
box at the top, and worked by the valve-gear. In
the figure, the top and bottom enlargements cc of
this inner tube are slid above the respective ports, so
that there is a free passage from the lower port into
the condenser; but the steam from the boiler, which
surrounds but cannot pass into the sliding tube, finds
open way to the upper port only, and by pressing on
the top of the piston, produces the down stroke as in
the old engine. This done, the inner tube ee, or
its intensity is 250°, although it can perform none of these opera-
tions, it can boil as much water, or raise as much steam of
any pressure under two atmospheres, as ever. At 200° it can raise
no useful steam and cook no meat, but it can brew as much beer as
ever. Spread too far to brew, it will boil. as much sugar in vacuo as
ever; too far for this, it will hatch as many eggs as ever: when
too diffused for the hatching of an egg, it will force as many pinc-
apples as ever; and when it will not aid fancy horticulture, it will
do better: it will warm as many dwellings as ever. Thus it'is
probable that if the heat of smelting and of a few such operations
alone, were made the most of, instead of being thrown away after
serving a single purpose, none of the fuel burnt to raise steam-
power, to cook, to brew, to wash, or to warm buildings, would be
needed. We waste most of the heat produced even by that
moderate portion which we cannot yet contrive to throw away
bodily in the shape of gas from coking ovens and' soot from
chimneys. Of course, any system that throws a nation on its
mines for support, can have but a lease of life limited at the
furthest by their extent.
STEAM-ENGINE.
711
slicle, is pushed down into the position of Fig. 2045,
so that its lower enlargement may stop the way from
the lower port to the condenser, while the upper one
stops that to the upper port from the boiler, but it
opens a way from

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The after-disposal
of the steam-water,
condensing - water,
and their released
air, is precisely as in
the single-acting en-
gine, except that all
the vessels through
which they pass must, to maintain the same rarity of
vapour, be (for an equal cylinder) twice as capacious,
as must also the boiler; or rather we should say that,
for the supply of the same power, all these parts
must retain the same dimensions as if the engine
were single acting, only the cylinder being reduced in
capacity one-half, because capable, in half its former
compass, of using the same amount of steam, and of
course yielding the same power. If the pumps were
made double-acting, (as some for other purposes have
been since Watt’s development of this principle,)
they too might be proportionably reduced, but neither
Watt nor any later mechanician appears to have found
the saving worth the complications necessary for that
end.
We have represented, however, in Fig. 20%, some
variations now generally adopted in the hot well l,
and feed-pump in. The former usually occupies the
top of the air-pump ll, in order that it may be quite
disconnected with the cold water cistern, and either
the whole lid of the air-pump, or a portion of it, as
shown in the engraving, opens as a valve when the
air-piston has in its up-stroke sufliciently compressed
the fluids above it, to lift this valve and drive them
out. From the top of the hot well proceeds the
waste pipe, and from a lower point the pipe n to the
feed-pump 772. This is now, owing to the high and
variable pressures of steam used in modern boilers,
made to force its supply directly into them, instead of
merely lifting that supply, as in Watt’s engines, into
an open reservoir of such a height above them that
the column descending from it should balance the
excess of the pressure of the steam above that of the
external air; then rarely exceeding a third of an
atmosphere, but now sometimes amounting to three
or four atmospheres, which would support an un-
wieldy height of water, and by a slight increase, drive
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Fig. 2045.

it to overflow like Worcester’s fountain. The present
feed-pump, therefore, is a forcing or solid-piston pump,
and usually of the kind called a plunger pump, (as
shown in Fig. 20414.‘, and similar in principle to the
pump of Marly, described under PUMP, Fig. 1777,)
the rod that descends through the stufling box being
large enough to occupy nearly the whole barrel, so
that, by plunging into the water (whence its name)
it must drive out a considerable portion, which can
only escape by lifting the valve 0', (here shown as a
ball valve or hollow ball, loosely resting in a conical
seat,) and transmitting its pressure along the feecl~
pipe pp, which is always full, to the boiler, uhich
receives at each stroke a supply equal to that which
the plunger displaces. But in rising, the vacancy
which it would leave is supplied by water from the
pipe n, lifting the ball valve 0, which is similar to 0',
and as neither of these valves will admit the return
of water once forced through them, every up-stroke
draws water from the hot well into the pump, and
every plunge forces it on towards the boiler. The
larger pump q used for pouring cold water into the
cistern at 7‘, still resembles in structure one of the
common domestic kind. [See PUMP, Fig. 1772.]
It will now be evident that the connexion of the
double-acting piston rod 0 with the beam above, can
no longer be by any sort of chain as in Newcomen’s,
because it has not only to pull down the beam, but to
push it up ; and as it is constrained by the lid of the
cylinder to move always vertically, its top evidently
cannot be simply attached to any point of the beam,
which describes an are; but by supposing the sector
fixed on the beam, as on Neweomen’s, in Fig. 2039,
to be cut with teeth, and the straight prolongation of
the piston-rod with similar teeth interlocking with
them, the desired end would be answered, since the
piston-rod would be exposed to no bending strain.
Watt’s better contrivance for this purpose we reserve
for later explanation, and proceed at once to the rota-
tive part. From the other end of the beam hangs the
cmnls-rocl G, Fig. 20441. It is thickened towards its
middle, in order to stiffen it against bending without
waste of material. Now, by alternately pushing
down and pulling up this crank-rod, the crank H con-
tinues its rotation when once begun, because the mo-
mentum of the rotating mass carries it across the two
cleazl points as they are called in each turn, where the
crank is upright or downright, and at which also the
piston being at the top or bottom of its stroke, is
exerting no force. In ordei' to produce sufficient
momentum for this effect, however, the quantity of
matter revolving has to be increased by attaching to
the axle a wheel with a heavy rim L L, called the fly-
wheel; and as the efiiciency of this in equalizing the
motion, depends on the qnanlily of motion that it
stores up, as it were, or absorbs in order to give out
again whenever the velocity tends to decline, it follows
that the larger the wheel, the less matter may it con-
tain; because; with the same time of revolution, the
velocity of its rim, (which is chiefly concerned in
storing up momentum,) will obviously increase as its
circumference, i.e. as its radius; and 100 lbs. moving
712
STEAM~ENGINE.
20 feet per second, will have the same momentum as
200 moving only 10 feet per second. [See STATIcs
and DrNAMIcs] In order to save material, there-
fore, the wheel is made as large as the situation will
conveniently admit, unless this would lead to a rim
moving faster than 60 feet per second, beyond which
its centrifugal force would endanger the flying apart
of the cast metal, of which it is composed. The
momentum of fly-wheels is found sufficiently to
equalize the motion, when so calculated that, if the
engine suddenly cease working, the power then yielded
by the wheel shall be from 3 to 4 times what the
piston without a fly-wheel would accumulate in
travelling from rest to its greatest speed.
Some persons who do not sufficiently regard the
fundamental laws of motion discovered by Kepler,
Newton, and Galileo, have imagined that force is lost
in circularising the motion by means of the crank,
or in regulating the motion by means of the fly-
wheel. Such is not the case. The only forces that
can absorb or destroy motion or motive power, in
machines whose parts do not stri/ee together, are fric-
tion and the resistance of the air. Without these,
the greatest mass, a planet for example, once brought
to move with a given speed, would require no fresh
supply of force to keep up that speed; the smallest
added force would accelerate and continue to acce-
lerate it as long as it acted. The action of gravity
upon a stone falling to the ground is a familiar
example. What we call moving power should always
properly be called accelerating power; and when-
ever it or any of it appears to be expended only
for the purpose of keeping up a motion uniformly,
neither doing work, such as lifting, cutting, spinning
&c., nor accelerating the machine, such a moving or
accelerating power is really employed in opposing and
simply balancing friction, and the resistance of the
air; which indeed, in some cases, as in that of a train
on a level railway, form in themselves the whole work
to be done. Now, the crank and the fly-wheel contri-
bute their share, with the other necessary parts of the
steam-engine, to both these resistances, but it is a
most insignificant share. The wheel by its weight
adds to that with which the axle presses on its bear-
ings, and thus somewhat increases their friction; and
the displacement of air by its spokes might be wholly
obviated by having no spokes, but a flat disc; while
the crank involves the absolute minimum of both
losses, which is possible in a conversion of one motion
into another. It is one of those cases in which the
simplest, most obvious, perhaps earliest solution of a
problem, is so obviously also the best, that, like many a
contrivance of unknown antiquity, (many a feature in
old architecture for instance,) by no progress of art or
science can it possibly be superseded or an] pressed
unless the work become one of mere ornament or
display. ,
Among the incongruous results of the system of
patents under which steam machinery has grown up
into its present state, none is more remarkable than
that which impelled Watt for some years to use a
ridiculously circuitous substitute for this ancient and

universal element of the simplest machines, the crank,
which a rival had actually managed to purchase the
monopoly of, so far as its application to the steam-
engine was concerned. He might almost as well have
had the monopoly of using screws in steam-engines,
or of using iron instead of copper in boilers. The
effect of this monopoly was to compel Watt to em-
ploy that useless invention of the “sun and planet
wheel,” which, having at once disappeared on the ex-
piration of the patent above referred to, we need not
describe, notwithstanding its great ingenuity.
The fiy-wheel, although correcting the increase and
decrease of power necessary in every single stroke,
and the total cessation thereof at the moment of
changing the stroke, with other short irregularities,
cannot evidently regulate or at all affect a change of
the velocity of the engine to a new velocity continu-
ing for many strokes to be different from the former,
or gradually increasing or diminishing. Such may
arise from a change in the firing and production of
steam, in the degree of coolness or of vacuity in the
condenser, (which may be affected even by changes of
temperature in the weather), or what is most common,
a change of the loan7 or resistance offered by the work
performed. Momentum can only soften down too
sudden variations, as a snzoot/zer, not a levcller or
absolute equalizer or governor of the speed, such as
the cataract is to the single-acting engine. For such
a governor Watt found a principle ready developed in
an ancient appendage to windmills. Merely trans-
lated from the carpenter’s into the iron machinist’s
style of workmanship, this gave the feature marked
r in Fig. 20414:. An upright axis is made to revolve
quickly, (in this case by a small bevelled wheel at its
foot, driven by a larger vertical one, which is fixed to
a pulley receiving motion by an endless cord sur, from
a similar pulley on the main axle x z) to the upper
part of this vertical spindle, are suspended by joints,
the two pendulums ending in balls, so that when at
rest, they touch the spindle, and when it revolves,
they fly out until their centrifugal force balances
their weight, which of course happens further off the
more rapid their motion. Two bars of half the
length of the pendulum, jointed to their centres, hang
down and are jointed at their lower ends to a collar
freely sliding up and down the spindle, but obliged in
so doing to raise or lower the lever z, whose other
end adjusts the degree of opening of the t/zrotlle valve
in a, or that which the steam first encounters in ex-
tending from the boiler, and by which it is shut off,
or admitted to work the engine. Whatever leads to
an acceleration of the engine, causes the balls to fly
out further or higher, thereby drawing up the collar
that moves the lever z, and this is so arranged as to
cause a throttling or reduction of the steam—way in a.
On the other hand, any sinking of the balls through
insufficient speed, must cause a wider opening of a,
and increased supply of steam. There is an in-
variable relation between the time of revolution of
such a pendulum, and the vertical depth or axis of
the cone described by it; that is to say, whatever the
length of the pendulum itself, it becomes so inclined,
STEAM-ENGINE.
713
that the depth from its point of suspension to the
plane of the circle described by that point in its mass
called the centre of oscillation, will always be the same
for the same period of revolution 5~being equal to the
length of a common pendulum that vibrates to and
fro in that same period ; and depending solely on the
amount of the force of gravity, which is measured at
any place by the distance a body falls in a second: so
that, to the distance fallen in any given time, the
length of pendulum vibrating in that same time, bears
a constant ratio, viz. as the square of the diameter of a
circle to half the square of its circumference, or as l
to 4: 9348. Now the depth fallen in a second hardly
varies anywhere to a barley/corn more or less than
16 feet 1 inch, (the variation being due only to the
earth’s centrifugal force), and 16 feet 1 inch is
493418 times the length of a pendulum vibrating
seconds, (i. e. to and fro in two seconds). So this
length, viz. 39'1393 inches, is also the depth of the
cone in which the conical pendulum or governor will
revolve once in two seconds; and the measure of
either kind of pendulum being as the square of the time,
a quarter of 391393 is the length of a lialf-second’s
pendulum, or depth of a governor revolving in one
second. So when the number of turns which the
governor is to make in a minute is decided on, the
depth of cone at which the lever 2 shall keep the
valve a at its mean degree of opening is also decided
on; and by so adjusting it, the governor can hardly
vary from this speed, so that the number of revolu-
tions of the axle K, or strokes of the engine, is also
made invariable. Thus an excessive production of
steam will only accelerate it to the very small extent
required to lift the collar of the governor as far as
shall so reduce the steam-way at a, as to keep back
this surplus steam in the boiler, where it may attain
any pressure, oven to the lifting of the safety-valve,
rather than allow the engine to be accelerated. And
however slowly it be produced, as much as ever will
be used at each stroke, owing to the increased area of
opening allowed it at a, until the boiler is emptied of
steam, or the diminishing pressure warns the fireman
to accelerate its production.
With regard to the moving of the slide cc, necessary
to change each stroke, it is now found most simple in
all rotative engines to derive this movement not from
the beam but from the axle K, because the slide must
evidently not rise when the piston or beam rises, nor
yet when they fall, but be moving fastest or in the mid-
dle of its stroke when they are stopping or changing
their motion, and itself stop (and if possible remain un-
moved for a time) when they are moving fastest. In
Fig. 20%, a wheel is fixed on K behind the crank,
with its centre not in the centre of the axle, whence
it is called an eccentric, and is embraced by a metal
ring forming the extremity of the light framed piece
8 s 8, called the e.rcentric-i'oll, which must evidently, as
the excentric revolves, be shifted alternately to the
right and to the left through a. space equal to the
diameter of the circle described by the centre of the
excentric, or twice the distance thereof from the
centre of the axle. The end of the excentric-rod is

jointed to a short arm hanging down from a horizontal
axis or arbor, seen out through at y, and which is thus
made to reciprocate through about a quarter of a
turn and back again. From another, part of the
arbor projects a similar arm in another direction,
(which is here equal to, but may be longer or shorter
than the first,) and this is jointed to an upright rod
Which lifts and pulls down, at its upper end, a lever
that acts on the rod of the slide cc. The arrange-
ment is shown needlessly circuitous, in order to com-
bine examples of the various methods used for
changing the directions of these reciprocating motions,
which are in hardly two engines conveyed exactly
alike.
We must now see how Watt met the difficulty he
had created by obliging the piston rod to rise and fall
in one straight line, and yet move the end of the
beam through a circular are. It mtg/it be met as
already stated by cutting teeth on Newcomen’s sector
(seen in Fig. 2039,) and substituting for his chain a
similarly toothed straight extension of the rod, such
as is called a c'ac/e. But it was Watt’s object to
banish from his engine everything approaching to a
blow of one part against another, or indeed an
alternate contact and separation of any parts but the
valves and their seats, where it is unavoidable. The
most perfect and lasting machinery is that in which
no surfaces, or portions of surfaces even, are allowed
to work together without remaining constantly toge-
ther, like an axle and its hearing, or the excentric
and its enclosing hoop; and although this perfection
can seldom be attained in the contrivance of machines
necessarily very complex from the variety of their
functions, yet all toothed wheels and racks should be
avoided where constantly-touching gear is possible.
The parallel motion is the name given to the ar-
rangement for effecting this, and it is founded on the
following principle—If, on the two centres at and a,
6


Fig 2046.
Fig. 2M6, we suppose two equal arms or radii to be
movable so as to describe with their ends the arcs
BB’ and b Z1’, and these ends be connected by a stiff
rod jointed to them both, this will, still leaving these
ends to move up and down their circular course, be
itself so moved thereby that its miclelle point will
describe very nearly a straight line, cc, as seen by the
dots marking its centre in several positions. The
course would be quite straight were each radius arm
always to move through the same angle as the other
7141
STEAM-ENGINE.
does, but as their ends would then plainly not preserve
an invariable distance apart, the connecting piece, by
obliging this, prevents that strict correspondence, and
this is the only reason its own centre deviates a little
to the right and left of a straight course, into an
almost imperceptible S curve. Now if the arms be of
such length that the arcs described by their ends


I
l
5
s
Fig. 2047.
interfere as in Fig. 2047, the same thing will hold
good (which might not have been obvious without
first considering the other figure), and the straightness
of the course of the third bar’s centre will be much
more nearly attained 5 as a trial of the drawing on a
large scale will prove. The motion may be continued
as far up and down as to make the connecting bar,
when at B b, or B’ b’, incline as much to the left as
it does when in the middle position to the rig/it, and
the top, middle and bottom places of its centre will_
be in one straight line. At two other positions
rather nearer the top and bottom than the mean
one, the bar will be vertical.
This arrangement is in fact the first of the two
forms of “ parallel motion,” introduced by Watt into
his beam engines. But it is not necessary that the
two arms AB, ab, be of equal length. One arc may
be more curved than the other, provided the point
taken in the connecting bar be no longer in its centre,
but nearest to that end which describes‘ the less
curved are, or which has the longer radius. Mathe-
maticians have taken much pains to investigate this
problem, and various rules have been given for calculat-
ing from the ratio of the two radial arms the ratio
in which the connecting bar should be divided by the
point to which the force of the engine is applied, so
that this point may most
nearly keep (as it can

the centre of each, and describe on it a semicircle.
Then take any distance AB, on one semicircle, and an
equal distance a b on the other, and from o and e as
centres draw the arcs B 1) and b cl, that is, transfer the
distance 0 B to e :o, and e b to 0 cl; and a straight line
joining D and (Z will cross the connecting bar A a in
the point e, which is the one required. If any other
equal distances had been set oil’ on the semicircles, as
A B’ and a b’, then, unless the latter cut off too much
(say more than half), of the smaller semicircle (as
this does to show the extreme results), the new line
D' (5' will cut so nearly in the same point e, that the
difference may be neglected.
Now suppose we have two radial arms thus con-
nected, one of them, A B, Fig. 2049, being the half of



Fig. 2049.
the beam of an engine, and the other a b, an equal or
shorter arm turning on a fixed centre a, for the pur-
pose of rectifying the motion of a point e in the con-
necting bar Bb, and suppose we lengthen the beam
to 1), and then take two more bars, one D E equal to
the connecting bar B b, and the other E b equal to the
prolongation of the beam B D, these four portions will
form a parallelogram B D E b, which, having a oint at
each corner, can change its form as the beam ascends
n\ D 1)’ \C
W / - -
.g/ and descends, making the angles all dill’er,
but the opposite sides will always remain
parallel, like the bars of a parallel ruler,


never quite keep) a 0
straight - lined motion;
and the rule chosen by
Tredgold as the best,
when put into the
form of a geometrical
construction, appears
thus,-—Let c 0 Fig. 2M8,
be the two centres of motion, and on, ca, the
lengths of the arms, represented in their mean posi-
tion, the only one in which they are parallel. Find
1"\
Fig. 204 8.
Q

or those of the frame of a child’s slate when
the slate is removed. Now, because B b
and DE remain always parallel, it will be
seen, that if, through any point e we draw
a " an imaginary line from the centre A until it
meet the other side DE atf, the ratio of A c
to of must remain always the same, though
both vary in length as the parallelogram
changes its form ;—and hence (by a principle familiar
to those who enlarge or reduce maps or drawings)
the paths described by these two points of must,
STE AM-EN GINE.
715
whatever their form, be similar, one being a mere
enlargement of the other. So, as there is one point
in B [2 made to describe a very nearly straight course,
a line from A, through this point a, will give us
another in D E with the same property, and available
for receiving the motion from the piston—rod, while 0
serves to hang from it one of the pump-rods which does
not need so long a stroke. This second kind of paral-
lel motion, then, is a mere addition to the first kind,
which always exists in the same arrangement whether
used or not.
Commonly, both are made use of in the engine-end
of the beam, as shown in Fig. 2050. The two hang/ing-

K c ~"
| \ - ........ -~ ~
_ _ _ - ~ -""‘ © _ W //l
B ;l"; ' " ‘
E ‘if (‘M/f‘
@ .
Fig. 2050.
lm/ts, A B, c n, are each double, with the beam between
the pair. Their lower ends are connected by the single
piece B n, and two radius-rods, like 1) n, nearly or ex-
actly equal to 0 o, are applied one on each side of the
whole, and move on a fixed centre at E. Therefore the
middle of c n is the point to which to attach the air-
pump rod, and an imaginary line from 0 through this
last joint F, points out the place B for the attachment
to the head of the piston-rod, which passes down be-
tween the two bars, of which n E is the visible one.
Such is a brief account of the more important im-
provements made by Watt in the steam-engine, whose
history has been truly said to terminate with his
labours 5 although later refinements in detail are innu-
merable. The double-acting engine, which has com-
menced so mighty a revolution in the whole of human
works and ways, that nothing since the death-dealing
invention of the 14th century seems, as a cansal disco-
very, comparable with it, and we are utterly astounded
in any attempt to realize the vastness of the completed‘
change which it must bring about,—the double-acting
engine can hardly be called more perfect now than
when Watt left it. The single-acting engine, being
required on a vast scale of size and permanence by
the Cornish mines, has made the greatest advances
since his time, and is now the more perfect engine in
its kind, although the more complex also.
Fig. 2053 is the side view of as much of the
modern Cornish engine as can be made distinct on
so small a scale.
The cylinder 0 is not only furnished with double
walls and a space of about an inch between them
full of steam, but outside this is a much larger enclo-
sure, (not shown in the figure,) confining a consider-
able thickness of ashes, by which the heat is so well
retained as hardly to be felt in the building containing
it. The top also has a covering of steam, and above
that a covering of enclosed air or ashes. The piston

which in Watt’s time was made tight by surrounding
it with a hempen gasket or flat rope (seen in Figs.
2044i and 2045) soaked in tallow, is now made en-
tirely metallic, which was first done on the principle
of A, Fig. 2051, a number of steel springs, around a

Fig. 2051.
central solid core, pressing out one or more rings of
separate segments 5 and these being in at least two
layers, one over the other, that the steam penetrating
the intervals of the first set might be stopped by the
second. After almost innumerable variations in the
springs and arrangements for equalizing their pressure,
engineers seem at length to find that all are excelled
by the method of substituting entire rings made like
B, thicker on one side, and about a hundredth part
larger than the cylinder they are to enter, then
cutting out a small portion, as shown in the figure,
and bringing the ends into contact, so that it forms
its own spring, and two of these hoops, laid one on
the other, as at c, and kept together by an upper and
lower plate, rather smaller than themselves, complete
the piston 5 a progress from complexity to simplicity,
singularly rare in steam machinery, and which we
cannot but think must eventually become more aimed
at than at present. Although each ring does not
press out with equal force at every part of its circum-
ference, and would therefore tend to wear the cylinder
oval, this is very nearly corrected by placing the
junctions at 90° apart.
Valves of single-acting engines are never sliding,
as that in Fig. 2044, but lifted up entirely from their
seats, to effect as sudden and complete an opening as
possible, and to this and their accurately timed
periods of opening and closing during the long slow
stroke, much of the superior duty of the Cornish over
that of all sliding—valve engines may, we believe, be
attributed. But it was soon found that mere flat
conical-edged valves, like those in Fig. 2043, to admit
the steam fast enough, required so large a surface,
that the power absorbed in opening them against the
pressure of the steam would be a considerable deduc-
tion from that of the engine, while even in small
engines none could be opened by hand without great
assistance from levers or other mechanical powers,
and therefore very slowly. A capital contrivance,
called the double-seal valve, of which Fig. 2052 is a
716
STEAM-ENGINE.
section, obviates this,
and is quite essential,
and has long been used
in all the Cornish en-
gines. In the aperture
art, which is bevelled
round to form the usual
valve-seat, are fixed 5
or 6 thin vertical plates,
of which 0 C are 2, ra-
diating from the centre
and supporting the flat
disc 6, the edge of which is also bevelled conically to
form a second seat. The valve itself, or movable
part, is a ring of the bulging form seen in section at
d, and shuts down at once on both these seats. If




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Fig. 2052.


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Fig. 2052.

they be equal, therefore, it may be lifted by whatever
will lift its mere Weight, the pressures of steam above
and below the protuberant surface destroying each
other; and if the lower seat be larger, as here shown,
only the excess of its area over that of the upper
measures the pressure effective in keeping it shut, A
bar across the top receives the rod by which it is
lifted (passing through a stuffing box), and when
lifted it admits the steam by the two ways shown by
the arrows, so that a steamway, equal to a pipe of a
foot or more in diameter, may be opened in a moment,
by hand, even for steam of the highest pressures.
It would be impossible to explain, without great
space and numerous figures, the gear by which the
three of these valves necessary to act at each stroke,
as described in reference to Fig. 2043, are opened and
LORINISH OR SINGLE-ACTING PUMPING ENGINE.
STE AM-EN GINE.
717
shut in the Cornish engines, by the various rappers or
projections from the suspended rod or, successively
acting on levers of different forms projecting from
three horizontal arbors, one of which governs each
Valve. It is a general principle, however, that the
opening of each, which is what most calls for in-
stantaneous motion, is effected not by the engine, but
by a weight heavier than the valve, pulling the other
end of the lever that raises it, and which the engine
only releases by removing a catch. The shutting, in
which suddenness is not so important, is effected
directly by the motion of the rod G, lifting these
weights again; and the shutting of the exhaustion
valve is often, and the opening of the steam valve
for a new stroke always, done by the separate rod 11,
that ascends from and is moved by the cataract I as
before explained, this answering the same end as the
governor in rotative engines.
The tappet that shuts the steam-valve, admits of
being placed higher or lower on the rod 6, so that the
time for which steam is admitted, before it is left to
expand, may be adjusted to the amount of work
‘that is to be performed per stroke. In some cases
only a twelfth of the cylinder is thus filled, (so far is
the principle of expansion carried,) and as the pres-
sure of the quantity thus admitted cannot be always
identical, the depth to which the piston descends
before being brought to rest by the resistances
and load at W, balancing the decreasing pressure of
the steam, is not constant; and to prevent its ever
striking the bottom of the cylinder, there is an addi-
tion to the top of the beam bearing a cross piece of
elastic wood D, which in too long a stroke strikes with
its ends on the spring-beams or spring-blocks K without
a violent shock. The speed of the piston in its
descent is first quickly accelerated during the admis-
sion of the steam, then gradually declines as it ex-
pands, and thus ceases and is reversed; and, in its
ascent, continually increases by the constant force of
the load at W ; so that the whole motion is inversely
like that of a shot fired directly upwards, which is
accelerated until it leaves the mouth of the gun, then
gradually retarded till it is reversed, and continually
accelerated again till it reach the ground. The danger
of a violent shock at last, therefore, which might
perhaps carry away the lid from the cylinder, is met
by shutting the equilibrium valve soon enough to
retain a “ cushion” of steam above the piston.
In these respects rotative engines have a great
advantage over single-acting, the crank not only
totally preventing all chance of the piston striking
either end of the cylinder, which is made long enough
to leave a clearance at each end,-but also obliging a
gradual change of motion from each stroke to the
next, like that of a pendulum, or of the shot above-
mentioned, when at the top of its flight. The chief
danger to them is the accumulation of a layer of
n ater in the cylinder, from either cloud or spray
raised in the turbulence of the boiling, and carried by
the steam into the cylinder, which is technically called
priming. Water being compressed no more by 22,000
atmospheres, than steam or air is by (me, of course a

layer of it exceeding the space allowed for clearance
in the cylinder, is equivalent to an equal mass of iron
suddenly introduced, or the shortening of the cylinder
by so much, and must immediately break whatever
part of the engine is weakest.
We may here notice that modes of imitating the
suddenness and nice timing of the Cornish valve
motions, with machinery of constant contact, have
been devised, though not much used in England, in
the smaller engines at least. With the common ex-
centric, very little can be done in this direction,
because the reciprocating motion which it communi-
cates to its rod, and thence to all the succeeding
parts, and the valves themselves, is evidently one of
just the same kind as the crank obliges the piston to
follow with such advantage, namely swiftest in the
middle of the stroke, retarded to the point at which
it is reversed, and not resting an instant, but turning
back like a pendulum. It is this not reslz'zzg which
makes it objectionable as a mover of valves, in which
is Wanted, if possible, an z'rztermz'tted motion, a rapid
change from one position to the other, yet begun and
ended without a shock, and then a rest in that posi-
tion during a considerable part of the stroke. Cer-
tainly something equivalent to such a rest may be
obtained by so forming one or more of the ports,
that the slide in travelling across it may leave an
equal and maximum width of steam-way open for a
certain time. Thus, Fig. 2054 represents the section
of the three ports as some-
times made on the side of l
a cylinder, the two leading ' to its two ends, and the in- u
\
t‘
termediate and much wider
\


. ll 2 i
one turning away to the con a, ? ll a denser; and of the slide i g g l
which is moved up and down 2% 1
across their mouths by its / é» / ‘
rod passing out of the valve-
box (not here shown) by a
stulfing~box. The slide is
hollowed in the form of a
box itself, and with such an
aperture, that its lap or mar-
“my \\\ \
\
@e/e/e/l' A
\\\\\ \\\\\‘ \\\\\\ \\
\\
Q’W/i/ %’
gin may just cover one port I/ / /;
of the cylinder before the A B
'. ' '11 com t
opposite maigi b g s o my. 205k
uncover the other, so that at
the centre of its stroke both are stopped, as at A, and
no steam enters either end. But owing to the narrow-
ness of these ports in the direction they are here
cut, (not in the other,) it very quickly opens to its
interior the whole of one, and to its exterior the
whole of the other, as at B; and however far it
travel beyond this position, their whole mouths re-
main in communication, the one with its inside, i.e.
with the condenser, and the other with the enclosing
valve-box, i.e. with the boiler, and during all this
time the effect is as if the slide were at rest. The
middle or condenser port may seem to require an ex-
cessive width to produce this effect, as it might other-
wise be itself narrowed to less than theirs, at the
718
STE AM—EN GINE.
extreme position of the slide; but in fact, both this
and the whole pipe to the condenser should always be
more capacious than the other passages, because the
less elastic rare vapour travels less rapidly, in pro-
portion.
But it is not possible in this way to carry the ex-
pansion principle beyond a very limited extent. For
this a more interrupted motion is absolutely neces-
sary, and that cannot be had from the common or
czreularexcentric. Hence exeentrics have been made
in other shapes, as that in Fig. 2055, which is meant


to move the slide shown in 4 positions in Fig.
2056. Of these, N is the position for beginning


\\\\\i\\\\\\\\\\\\\\\\\\\\\ \\
/


\\\\‘\


Fig. 2056.
the up-stroke, the steam freely entering the lower
port and issuing from the upper into the middle or
condenser port. 0 is the position for the latter part
of the same stroke, the eduction continuing as before,
but the access to the lower port being stopped, that
the steam below the piston may drive it up the rest
of the way by expansion. B is the position for begin-
ning the down-stroke, being the converse of N, and Q
the converse of o, for finishing it. Now the excentric,
Fig. 2055, has its outline formed of 4c circular arcs, 92,
0,19, 9, all described from the centre of the axle B,
but with different radii, and connected by sweeps to
avoid sudden shocks. The diameter, however, taken
in any direction through the centre of the axle, must
be equal to the distance between the 2 friction wheels
0 c, which turn like sheaves of a pulley between 2
oblong frames (one of which here hides the other), and
from their united ends proceeds the rod 1) that carries
the motion to the valve-gear. Thus the revolution of
this excentric puts the rod into 4.‘ different positions,
and keeps it some time in each. The ratio between the
time of passage, or angular extent, of the are a, and
that of 0 (which must always be the same as between
p and 9) determines how much of the cylinder shall be
filled by influx compared with the space filled by ex-
pansion, or what is technically called the grade of
expansion. Often, therefore, the means of changing
this is provided, by making the excentrie thick enough
to be shaped as though composed of several (in this
case 4) excentrics, laid one on another, the sweeps

from g to v, and from o to p coinciding in all, but that
from a to 0 occurring a step later in each, as also that
from p to g (the former cannot be seen, it being 011
the other side). Then, by slipping the frame and
friction~wheels to or from the spectator, it may be
made to receive the action of any one of these differ-
ent forms of excentric, according to the greater or less
load on the engine, and less or greater advantage to
be taken of expansion.
Such forms are not commonly called excentrics,
but the projections on them came, in this case expan-
sion cams.
Artificial circumstances arising out of legal and com-
mercial anomalies, occupations dependent on fashion
and caprice, on the over-growth of towns, &c., may
evidently cause (even in stationary engines), the
naturally paramount objects of fuel-economy, dura-
bility and safety, to be outweighed and become secon—
dary to others, as economy of space, of water, of
particular constructive materials, of particular kinds
of workmanship, &c. 5 and hence give birth to various
minor or accidental forms of engine, besides the two
natural or standard kinds above described. Of these
the chief, (besides the land and water locomotives,
which we reserve until last,) are, I. the double—
eyh'vder; II. the rotary-disc; and III. the bz'yb-pres-
sure, more properly called the von-condensing engine.
I. No sooner had Watt proved the great increase of
duty to be obtained by the expansion principle, than
the apparent inconvenience of the continual diminu-
tion of the moving power during the expansion,
(though it really tends to equalize the motion, which
would otherwise, with an uniform power, as in the
return stroke of the Cornish engine, go on with
acceleration,) led various inventors to contrive engines
in which the steam, after filling one cylinder by its
full pressure, should be allowed to proceed from that
into a larger one by expansion only. Hornblower
seems to have been the first to introduce the plan,
although a double-acting engine of this kind is now
known as a VVoolf’s engine.
In the form given to it by Messrs. Hick & Bolton,
the two cylinders, which have their capacities in the
ratio of l to 4, (namely, their diameters as 23 to 40,
and their lengths as 3 to 4d,) stand side by side, the
larger under the extreme end of the beam, and the
smaller a fourth nearer its fulcrum, so that one jointed
parallelogram for parallel motion serves to receive at
different points the heads of both their piston-rods,
which are thus obliged to rise and fall together. The
small cylinder has its valve-boa‘, that is to say, a
contrivance such as above described in Figs. 2054
and 2056, the two ports to the top and bottom of the
cylinder being lengthened passages attached to it,
or formed in a projection cast in one piece with
it, and coming nearly together in the centre of its
height. This wastes at each stroke the quantity of
steam contained in one of these passages, but is now
generally adopted in all but the largest engines, to
save the material of a long steam-chest and slide,
these being reduced to such a length as merely con-
tains the two apertures or entrances to these ports,
STEAM-EN GINE.
719
and the third opening between them, leading away
laterally to the condenser. From the valve-box of
the smaller cylinder, however, of this form of engine,
this passage of exit leads only to the steam-chest of
the larger, or rather to one of two upright tubes
standing beside it, both of which tubes communicate
with the top and bottom thereof by double-seat valves.
Entering and filling the first of these tubes, it finds
the valve at that end, which answers to the end of
the small cylinder it has just left, shut, but the con-
trary one (answering to that at which the small
cylinder is receiving steam) open, and thus it drives
the large piston in the same direction that the small
one is being driven at the same time by fresh steam
from the boiler. Meanwhile, the steam on the other
side of the large piston, which has successively filled
both cylinders, and is four times rarer than it was in
the small cylinder, is passing into the second vertical
tube, whose foot leads straight to the condenser.
Thus the sliding-valve, and the more perfect or Cornish
mode of directing the steam, are both used in this
engine, the former for its first admission into the
small cylinder, and the latter for its future progress
when less elastic, and therefore requiring larger
steam-ways to pass through in the time allowed, and
more instantaneous and well-timed opening and shut-
ting. The gear acting on both the slide and the four
doubleseat valves, however, is moved by an excentric
on the axle, as in Fig. 2044., and therefore is gear of
gconslani conlacl throughout, nothing ceilc/iing, or
tone/ling, and leaving another, as in the Cornish gear.
II. Rolang engines, of which almost innumerable
forms have been patented and abandoned, are those in
which the steam gives uninterrupted (and therefore of )
course rotary) motion to the very surface or surfaces
on which it presses. These engines originated in the
erroneous but prevalent notion before alluded to, that
motive power may be lost or diminished in any other
way than by friction, shocks against imperfectly elastic
matter, fluid resistance, or by doing useless work,
(which indeed includes both the latter.) Of course,
the average resistance which a crank could overcome
all round its circuit, is less than the piston—rod could
throughout its double stroke, but only in the ratio
that its average velocity is greater, the path described
in the same time being longer as 31416 to 2, the
circumference of a circle to twice its diameter. The
greater distance travelled ust compensates for the
diminished load moved, as in all such cases. But
this is no loss of motive power, any more than it is a
loss for the muscles of our upper arm to pull the fore
arm close to its fulcrum, the elbow, with an immensely
harder pull than we can exert at the hand, where the
resistance is commonly met, for we move the hand
through a space just in that same proportion larger
than the muscles contract through. Is it expected
that a piston only able to lift directly, say 100 lbs.
2 feet in a second, is by means of the crank to lift
the same 100 lbs. 3'1416 feet in a secondi> But
some ask, is there not serviceable momentum lost in
stopping and reversing the motion every few seconds?
Certainly, if the motion he slapped, instead of step-
ping ilselj,’ which is what it ought to do in every
engine; otherwise there is a blow or slice/e, which,
against imperfectly elastic bodies, will indeed involve
loss of power. But the fact is, that while the reci-
procating piston mag change its motion without any
shock, or anything equivalent to it, the rotary one
cannot do so. For, in the first place, just as much
momentum must be reversed in the revolution as in
the double stroke. A revolving body must at one
time be moving northward, at another southward.
Therefore it must, in half a turn, lose all its north-
ward velocity, as surely as the reciprocating body
must. Now the latter may lose it as an arrow shot
straight upward, or the descending Cornish piston
does, viz. by the resistance of the load only, (besides
necessary friction,) the won/e to be (l0ne,—~thc water to
be raised. (The Cornish piston is merely jerlceil
down, and left to spend its impulse and rise again.)
But whatever the rotating body loses, must be by a
resistance foreign to the work done, viz. by the re-
sistance necessary to confine it to the centre, or
restrain what we call the centrifugal force; for that is
the name given to the momentum thus destroyed
continually throughout the revolution, and which
altogether is just as much as the piston would lose
if striking suddenly against both ends of the cylinder;
changing its motion not as a pendulum or Cornish
piston, nor even as the clapper of a hell, but as an
electrical dancing figure, urged with unchecked ac~
celeration till it strikes each plate. Whatever would
be lost by these shocks, must alive/gs be lost during
the revolution, in the shape of that continued accu-
mulation of atomic shocks which we call friction: an
addition by centrifugal force to the necessary friction,
whether of an axle, or an enclosing case.
Besides all this, it is easily proved that while the
fit of an ordinary cylinder and piston constantly
improves by wear, that of every possible rotary
arrangement must as constantly deteriorate; for the
various parts of the same rubbing surfaces move with
different velocities, whence it is impossible for them
to wear equally. They must wear open at the parts
furthest from the centre.
The extreme economy of space, however, in one
rotary engine, Bisliopp’s Disc Engine, (represented in a
steel engraving,) has brought it into some usein densely
populated towns. In order to understand its action,
let us imagine a ball A, (Fig. I.) into which the cylin-
drical rod 0 is inserted so as not to shake laterally.
Let the ball be in two halves, between which the disc
of card B is firmly held at right angles to the red A c.
If its top c be carried round the circle a c, while the
ball constantly occupies the same place, the planes
successively assumed by B will change, as if the whole
revolved round the imaginary axis (I. But to resemble
the motion of Bishopp’s disc, there must be no such
actual rotation of the ball and disc, but only of the
I point e; and such a motion of the disc as to make its
plane vary and take all the positions of one thus ro—
tating round the axis cl. Its matter does not revolve,
though the space filled by it does; and to imitate this,

we must keep the same points of its circumference
'7 20 STEAM-ENGINE.
towards the same 'points of the compass, notwith-
standing the revolution of 0. Cut a slit 6 along one
radius of the disc, and insert therein the piece of card
D, Fig. 11., having its concave edge out to fit exactly
the ball A; and fix D vertically in one position by in—
serting it, up to the dotted line, between two leaves
of a table. Now if the slit e be wide enough to slide
freely up and down D, and allow the disc to incline
itself considerably to the plane of D, we may carry a
round the circle 00, keeping the ball always pressed
into the concavity of D, or always filling one position
in space, and the disc 13 will fill the same positions as
if it revolved round (l; every point of its edge be-
coming successively the highest, and (after half a re-
volution of c) the lowest, although it always keeps
the same distance from the fixed partition D, and only
moves up and down like each point in a cord along
which waves are travelling, or each particle of matter
in a real wave. Now, in order to see how the steam
imparts this motion, we have only to add two conical
surfaces, above and below the disc, as in Fig. III.
such that were they complete cones, their points
would meet in the centre of the ball A; to fit the
surface of which they are truncated, and they may be
kept steady by intersecting the plane D. If their in-
clinations be just equal, it is evident that the disc
may be kept in contact with both, one whole radius
touching one cone, and the whole of the opposite
radius the other cone, perpetually, as c revolves.
These cones form the two ends or faces of the
chamber of the engine, (or cylinder as it is commonly
called, from the habit of referring everything to the
old form of engine,) and its remaining enclosure must
evidently, to fit the edges of the disc in all its
positions, be a spherical zone; but this need not be
added in order to understand the action. The whole
chamber is of course always divided equally into two
parts by the disc, and in the two positions where the
radius 6 touches either cone, the half on one side the
disc (as, in Fig. III. that lzelow it) is left entire, while
that on its other side (in Fig. III. that'alone it) is again
divided equally by the fixed partition D, into two
quarters of the whole capacity of the zone, although
they each occupy lzalf its circumference, (as the un-
divided half does a whole circumference, except the
thickness of D.) At this moment one of these equal
spaces above the disc is in the middle of its connexion
with the condenser; and in the other, the steam, just
disconnected from the boiler, is exerting its expansive
power to wedge apart the disc from the cone above,
216. to remove their radius of contact further on, and
extend itself from half into the whole circumference,
when it will occupy the greatest space which it ever
can do, viz. half the zone. And the other space above
the disc, (for we are speaking now of what takes
place on one of its sides only,) the other space will
have been reduced to nothing, the touching radius
which bounded it behind, having advanced round
halfa circumference and come to the slit 6, which is
now at the top of the partition D, instead of the
bottom. At this instant, then, the whole space above
the disc is undivided and full of steam, which at the

same moment finds a way opened to the condenser;
while the touching radius, advancing pasl the par-
tition D, leaves between itself and that partition a
small new wedge-like space, into which the steam
from the boiler is admitted, and which it speedily
enlarges; and when out off from the boiler, continues
to enlarge by its own expansion, as already described ;
the half filling of this and half emptying of the other
space bringing us, by another half-revolution of the
touching radius, (and consequently of the end of 0,)
round to the position of Fig. III. from which we started.
It will thus be evident that the ports for inlet and
outlet of the steam, on this side only of the disc, are
placed close to the partition D, one before, and one
behind it, that the latter may be constantly open to
the condenser, as the former would be to the boiler,
were there no expansive working, (which may be
carried perhaps more easily to a great extent in this
than in any other form of engine,) and that, unlike
the single side of an ordinary piston, which is alter-
nately all pressed by steam, and all left unpressed by
its removal, a single side of the disc is only at two
moments of the revolution thus exposed wholly to
pressure or wholly to exhaustion, and at all other
times varying portions of its area to each. All this,
‘of course, takes place exactly the same on the other
side the disc, half a revolution earlier or later, the
space on that side being just filled, and replacement
by fresh steam just commencing, when the space on
this side is divided in halves, one in the middle of
enlarging, and the other of being exhausted; so that
the utmost moving power derivable on one side occurs
when the other is powerless; the arrival of the touch-
ing radius at the partition D, (or of the slit 6 at the
top or bottom of its stroke,) being a momentary in-
terruption to the action of one side only of the piston,
whose two sides act independently. And as the
surface not pressed on one side the disc equals at
every moment what is pressed on the other, the whole
area pressed is constantly the same, viz. half the sum
of the disc’s two faces; so that the motion and power
would be perfectly uniform were the pressure of steam
so, or were there no expansive working; and the only
inequalities arise from its diminished pressure when
expanding.
Thus it happens, that a fiy-wheel, not l-third the
size of that required by a common engine of equal
power, suffices for this admirably compact contrivance;
and the connexion with it being not necessarily more
than a simple application of the end of c to one of its
spokes, without beam, parallel motion, or crank-rod, the
whole is easily compressed, when necessary, into even
less compass than the engine here represented.
The zone, or working chamber, is commonly, as here,
fixed upright or with its axis horizontal, and the disc-
rod 0 c, which is fixed firmly through the globe A, has
2 semicircles passing over the chamber to help to
steady its motion, which it communicates to a wheel
by its end 0 turning in a socket or kind of universal
joint. This wheel is on one end of the axle, which
bears also the flywheel H, and the two excentrics x .n,
the' larger for working by the rod 9, the air-pump
$1.”. ..._-... /Q_. ‘.3, . 7, _.- .. .i .. .. .- ..
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Lrr . ,. 4?? P .,..__ _ , z .1




an
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- ___~_.-_—_._—--V~ i_<'_--_—-

STEAM-ENGINE.
721
standing in the condenser e, while the smaller per-i
forms the less forcible reciprocating motions, including
those of the slide-valves in the box n, by two arms
from an arbor changing the vertical motion of v into the
horizontal one of e e the valve-rod. The governor K
regulates by the rods ff the throttle-valve in the
main steam-pipe r, all these details being as in other
engines. Perhaps the air-pump may eventually be-
come a miniature of the disc chamber itself, and its
principle be extended to pumps even for other pur-
poses 5 but the great obstacle both to this and the use
of the engine, will be the extreme accuracy of fitting
required by the working parts, even if they can be
made to retain this accuracy for any length of time.
The circumference of the disc B B is of course made to
fit the zone by piston-rings, and presents no more
difiiculty than the ordinary piston. Against the
stuffing-box of the ordinary engine (the simplest pos-
sible mode by which the motion generated within a
steam-tight space can be conveyed out of it), we here.
have to set the two concave surfaces in which the
globe A works 5 and there still remain all the nicest
and most difficult adjustments of the disc, wholly ad-
ditional to these common to all engines. The joints
abovementioned, like that round a common piston,


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Figs. 2057, 2058
sibly do without, and which add to the first cost. They
are the exact reverse of the Cornish engines (although
both species make use of the highest pressures),
economy of fuel being here made entirely secondary
to that of construction. The condenser and its ap-
pendages are therefore omitted; and all the power
V0 L. 11.

separate steam from rarer steam or vacuum by a con-
tact of considerable breadth, as broad indeed as it may
be desired to make it, and commonly as bread as the
piston is thick. But in ‘the two radii of contact be-
tween the disc and the cones, a mere line has to sepa-
rate steam from vacuum, and as every radius succes-
sively forms this line, the whole of each of the four
surfaces requires extreme accuracy. Again, the two
contacts of the slit 6 with the partition 1), must equally
be reduced to linear ones, by either sharp-edged
or rounded linings to the 2 sides of the slit, and
pressed to the partition by springs, for otherwise the
disc could not assume, as it must, different inclina-
tions to the partition. Now in order that all these
linear contacts may be steam-tight, an amount of
accuracy is required which has not been obtained
until very lately, and this will limit the use of an
engine which depends on such high finish. Their
friction, too, must absorb much power, and more than
counteract the saving thereof in the edges of the
piston by their moving through so much less space
than the steam.
III. What are called niglzpi'essni-e engines consist of
merely the absolutely necessary parts of an engine,
divested of all those contrivances which it can pos-









ELEVATIONS 0F HIGH-PRESSURE ENGINE,
obtainable from the vacuum-forming property of steam,
amounting, we have seen, in the gross, to 1,700 cubic
feet of water (i. e. about 10,500lbs. avoidupois) lifted
' 33 feet high by the evaporation of 1 cubic foot, re‘
quiring 5 lbs. of coal—all this is dispensed with 5 the
eduction passage leading not to a. condenser, but
3 A
722
STEAM-EN GINE.
merely to the open air, as in Leupold’s engine, Fig.
2040; so that the piston is pressed on the side of the
issuing steam by the common atmospheric pressure
of 15lbs. per square inch, which (instead of the llb.
or so exerted by the cool vapour of the condenser in
other engines) must be deducted from the pressure of
the entering steam in order to find that pressure
which is effective in driving the piston. This, the
simplest possible steam-engine, is in fact but a double-
aclz'ng cannon, a cannon of which the ball, or piston, is
driven alternately from. end to end by a body, more
elastic than the air, alternately introduced at each
end, both ends being closed andfurnished with touch-
holes; but the vapour is produced outside, and ad-
mitted through these, 2'. e. the coal is burnt outside
the gun instead of within it; water is substituted for
saltpetre; and (last, not least,) as the object, produc-
tion is substituted for destruction.
There being no reciprocating motion to communi-
cate except that of the valves, and of the feed-pump,
if any, no beam and no parallelmotion is used in these
non-condensing engines. The piston-rod head is kept
to its straight-lined course by sliding, with or without
friction-wheels, along straight iron guides, of which
there are usually a, which (unless the cylinder be for
some peculiar purpose placed in some other position
than vertically) stand upon and are bolted to its lid,
as at c e, Figs. 2057 , 2058. From the ends of the cross-
head, 0 c, descend the 2 crank-rods nn, to 2 cranks
x K, on the fly-wheel axle, which passes under the cylin-
der,—and an excentric on this may work the slide of
the valve—box immediately over it, although a more
indirect gear is generally found convenient. In the
figure, an excentric under the cylinder lifts and de-
presses by the short excentric red X, the lever L, whose
other end moves the valve-rod ascending vertically to
v. The chain of levers from the governor to the
throttle or regulating valve at s will also be under-
stood by inspection.
Expansion cannot be carried nearly so far in these
engines as in others, because, in order to take the
same advantage of it, the steam can at the end be
reduced only as near to the atmospheric pressure, or
151bs., as that of condensing engines may approach
to the condenser pressure, or about llb. Let us
suppose the excess, or the effective pressure left at
the end of the stroke, to be in each case 5 lbs. Then
the final elasticity of the steam is in one case 20, in
the other only 61bs., and to take advantage equally
of expansion, the steam must originally have a pres-
sure higher in the non—condensing‘than the condensing
engine, as 20 to 6. Or let the final effective pressure
be 1 1b., then the final elasticities of the steam are in
one case 2 lbs, in the other 16; and steam of eight
times more pressure must be generated in the one
boiler than in the other, in order that it may econo-
misc to the same extent. “
Steam-Boilers, which, although necessary to the
-' generation of the power, are quite independent of the
‘ engine, properly so called, have assumed the following
chief forms for stationary engines. Passing over the
alchymist’s glolles, and Newcomen’s, lzayslaele boilers,

as founded on no accurate observation of the subject,
and carrying out no true principle, (except perhaps that
of avoiding upright sides, for a reason to be presently
explained) we find Smeaton to have first recognised
the economy of enclosing the fire wholly within the
mass of the water. WVe ventured to express our
opinion that when Watt made an alteration in this ar-
rangement, he retrograded somewhat in omitting the
internal furnace, but he introduced What is called the
wagon boiler, the earliest that still continues in use.
As first made, this was of the exact shape of a wagon
and tilt, z'. e. a long parallelopiped finished above by a
half cylinder; the whole of the bottom, the ends, and
the sides up to where the cylindrical bending com-
mences, being flat and at right angles. N ow, both
water, air, and gases being most imperfect eonduelors
of heat, 2'. e. hardly permeated by it w/n'le at‘ rest‘,
although readily moved by it if unequally distributed,
provided awarmer portion be beneath a cooler, so
that their density may cause them to change places,
the heating must be almost wholly effected in this
latter way. A flat bottom, then, exposed to the fire,
is the very best kind of surface for exciting such
movements; and every surface so inclined, as to lean
over the fire, or have the heating air and gases
below every point, and the water alone every point of
it, will be, however little inclined from verticality,
almost as good as the horizontal one, each point con-
tinually sending up the particle of water heated byit,
and receiving a cooler in its place; or, while boiling,
sending up its small bubble of steam, and receiving an
equal bulk of water. But when the wall is gzn'le ver-
tical, the case is wholly altered. The air and gases on
one side, and the water on the other, may each cir-
culate independently, and almost without communica
tion of heat, since nothing is stopped or diverted
by either surface; whereas when it is inclined, the de—
scending coolest particles of water are constantly fall-
ing upon the inner face, and the hottest ones of air
and gas rising and striking against the outer.
In order to gain more surface than that afforded by
the bottom only of these wagon-boilers, Watt after-
wards hollowed their sides, as in Fig. 2059, (the cross
section of one of his most improved boilers), so as to
make the upper half, or a little more, of each, to lean
over the fiues AB, and although their lower half
would seem to be even less effective than an upright
surface, it is hardly any loss, as the steam produced
by either is almost nothing. He also hollowed the
bottom, apparently to resist the pressure, on the prin-
ciple of the arch; since any flat surface in boilers
evidently tends by the pressure to bulge outwards,
equal areas of surface giving room to more and more
bulk of contents as they approach nearer to sphericity.
But, by making any surface convex inwards, it will be
secure against outward approach to flatness if the
ends of the curve be kept from moving further apart, ‘
either by abutments of masonry, or by being tied to~
gether. Thus, some bands ‘passing round this. boiler,
and straight across the concavities of the sides and
bottom like bowstrings, would obviate the necessity
for any of the internal stays commonly applied, ex~
STEAM-ENGINE.
723
cept those used to hold the flat ends to each other, or
to the sides. Indeed, only flat‘ surfaces can create any

wa'rr’s wxeonmornen.
129.2059.
necessity for internal stays; inwardly curved ones ad-
mitting of being thus stayed externally, although the
principle seems not to have been applied.
These boilers are so set, that the flame and smoke,
passing from the grate under one end to the further
end, then turns into one side fine A, and comes back
to the front end, which it crosses by a flue above the
fire door, across'from A to B, and then along 13 to the
chimney at the further end. The aperture of this is
often regulated by a reg/"acting damper, i. e. a plate D,
sliding in grooves, and suspended by a chain passing
over two pulleys, and more than counterpoised by the
weight seen within the standing pipe P. This pipe is
that into which the boiler’s supply is poured by the
feed-pipe n, and (unless the steam’s pressure be
below that of the air, a very rare case indeed, because
although condensing engines, when once started,
could be kept going with such steam, the power
obtained would be disproportionately below what the
same cylinders are capable of,) the water in this pipe
P must of course stand as high above that in the
boiler, as to balance the excess of the steam’s pres-
sure above the air’s, or about 33 feet if that excess
be one atmosphere, 11 feet, if it be 5 lbs. per inch, 850.
The counterpoise of the damper floats on this water;
and hence, when the pressure increases, the rise of
the water and float allows the damper to descend and
diminish the draught through the fire, and conse-
quently the consumption of fuel and the production

of steam. When too little is formed, the pressure
decreases, the water and float sink, the damper is
drawn up, and the fire increases until equilibrium
between the production and expenditure of steam is
restored.
The regulation of the supply of water is the most
important of all the wants of the engine, because its
sinking too low may leave some portion of the boiler
dry near enough to the flues to become much hotter
than itself, and so, on being again covered by a fresh
supply, evaporate it so rapidly as to endanger explo-
sion; while too much water will obviously increase
the risk of some being carried up with the steam (or
priming, as it is called), and accumulating in the
cylinder until it stop the piston short of a full stroke,
and break down some part of the machinery. Thus
the presence of too little water endangers the boiler,
and that of too much, the engine; and hence the ob—
servation of its exact level must be made as easy and
unerring as possible. A window, or rather loop-hole
of thick glass, is the most perfect means, but has been
little used, from the difliculty of keeping it cemented
steam-tight. A piece of glass tube is more easily
kept cemented into two brass sockets for its top and
bottom, and these screwed into the boiler at a little
distance above and below the proper level. But as
some obstruction in these may prevent the level keep—
ing always exactly the same in the tube as in the
boiler, a second test is provided in the gauge-coats e,
which terminate two slender pipes, one descending to
a little below, and the other to a little short of the
proper level of the water, so that if on opening them,
both yield water, or both steam, the level is known
to require correction by stopping or increasing the
supply.
Any self-acting apparatus for assisting in this duty
has perhaps been justly condemned, as tending to a
relaxation of the watch that, in any engine supplying
(as all but toy steam-engines do) the place of several
human hands, should be obliged by law to receive
at least the undivided attention of one man. Such
an apparatus, however, has been devised, and consists
of, first, a partition across the standing pipe 1? near
its top, with a smaller short tube ascending from
a hole in its centre to allow the chain of the damper
counterpoise to pass through, but form around it an
annular cistern, in which the water, entering from
the feed-pipe F is retained, except when a small valve
inits bottom is lifted and allows some to fall through
and supply the boiler. This valve hangs by a rod to
the lever L, very near its fulcrum; and from the same
end of this lever hangs a weight, while from its con-
trary end hangs by a wire, passing through an easy
sort of stuifing-box, into the boiler, the float s, made
of stone or metal, but so counterpoised as to float,
and broad enough and heavy enough for its rising and
sinking to overcome the friction of this stuffingbox,
and thus lift or close the valve hanging from L, ac—
cording as a supply is wanted at the moment or not.
The increased pressure, however, which must soon
become universal in modern engines, evidently will
render, if it have not already nearly rendered, the
3 a 2
7241 ‘
STEAM-EN GINE.
mode of supply by the above standing pipe obsolete.
For a height of 33 feet for every atmosphere (or 2 feet
2 inches for every pound) of pressure beyond that of
the air, cannot be allowed this apparatus even with
the present .very general use of steam of 3 or 4: atmo-
spheres, which we believe it will be found worth
while yet greatly to exceed. ' The feed-pipe must
therefore pass direct from the plunger-pump (see Fig.
2053) into the boiler. Now this, although it does
not render a mechanical governor or regulator of the
supply necessary nor desirable, yet renders mechanism
for the regulation of it, by a human regulator, abso-
lutely essential. For the feed-pump, left to itself,
must introduce a precisely equal bulk of water at each
stroke, but the quantity evaporated by each stroke,
or even by each thousand strokes, cannot be made to
preserve anything like equality, even with an engine
doing the same work constantly. Every time the
safety-valves were opened, the level would sink and
then remain permanently lower; and every time the
pressure were purposely raised or lowered, even with-
out altering the grade of expansion, the quantity of
water returned at each stroke must evidently be quite
altered if the level is to be maintained. The simple I
expedient is a stop-cock of variable aperture in the
pipe by which the feed-pump draws its supply from
the hot well. This so reduces the aperture, when
necessary, that there shall not be time, during one‘
stroke, for a bulk of water, equal to tne plunger, to:
pass through this aperture into the pump, in which, I
consequently, a vacuum will be left when the plunger
is furthest withdrawn. The power ‘spent in thus
withdrawing it against the whole pressure of the _
atmosphere is‘ obviously regained by that pressure'
aiding its return stroke. .
The other essential appendages to all boilers are
the safely-valve, the pressure-gauge, the simplest form
of which is described under STEAM, and a man—kale
for entering the boiler in order to repair it. '
l/Vatt sometimes added to the wagon-boiler a square
flue, passing through the water from the end farthest
from the fire, to the chimney at the fire end. The
motive for its square ‘form, especially as two sides
were placed upright, is inconceivable. ‘Such flutes are
now always of the shape most easily made, 2'‘; ‘e."cylin- '
drical, and generally ‘large enough to receive the whole '
fire-grate and ash-pit in their mouth, thus reviving 7
Smeaton’s excellent principle of surrounding the fire '
with water in order that no heat may be spent on "
anything else directly; while retaining Watt’s prin-
ciple of lengthening the boiler so that it may take heat
from the products of combustion for some time after
they have been burnt. This arrangement, with the
outer case also simplified to the "easiest and probably
best shape, a cylinder, forms what-is now called the
Carmela-boiler. It is set either on a central longitu-
dinal wall, leaving 2 fines or air-casings to its sides,
as in'_Fig. 2060, or 2 parallel walls, forming besides
these a flue under the bottom. In both cases, the
products of the fire pass first along a central flue,
either through or under the boiler, then-back through
1 or 2 others to the fire-end,- the- arrangement being

called a split‘ draught when it returns by 2 of them
and finally along one in the same direction as at first,
to the chimney.
Fig. 2060 represents the boiler as an oval cylinder

‘—-—_-——-—_-—--———--—-_._\
. ' {.‘I' r~
,//////////// .Fz'y. 2060. comnsu BOILER.
with its longer axis vertical. This, although not a
common arrangement, is far better than one often
adopted with the same object 5 the object of keeping
the water, and consequently the flue“ (which must
always be preserved from the risk of having its top
uncovered) lower, and so leaving more steam space
than is attainable with both boiler and flue cylindri-
cal. To this end it is usual to make the flue elliptical
with its larger axle horizontal, but such a figure op-
posed to external pressure is most unsafe, and explo-
sions by collapse of the flue are more destructive than
others, in consequence of the fire and grate being
blown out as from a piece of ordnance in the exact
“direction most certain to do mischief. All pipes ex-
posed to- external pressure should, unless provided
With internal struts, be made as exactly cylindrical as
possible, and the end‘ proposed can be better attained
as above, by an oval form in the boiler itself.
' As even a perfect cylinder, whenever pressed from
without, is in unstable equilibrium, every deviation
from the circular form tending to z'rzcrease until it
collapses, the principle of using a broad elliptical flue,
whose upper and lower sides are kept apart by vertical
tabular-strata, allowing the water to circulate, is cer—
tainly a great advance. These short tubes should be
conical that their sides may overhang the fire or hot
air, and if we consider that all the steam generated
in them has to leave their top, and need only be re-
placed by a thousandth or less of its bulk of water
through their foot, they may evidently be made very
conical with advantage. ‘ In Galloway’s patent boiler
on this principle, of which a cross section and a plan
are represented in Figs. 2061, 2062, these tubes are
admirably arranged, but only slip/ally conical. The
two fire-grates are for the purpose of so feeding them
alternately, that the smoke emitted by each, when
newly fed, may be consumed by the ‘other to some
extent.1 '

v,
r


(1) The details of the Cornish boiler, with Sylvester’s fire-doors
850. used in the experiments on steam-coal, 8zc., are given in the
‘article FUEL. ~ '
STEAM-ENGINE.
725 ‘
The proportionate length of boilers still varies-from
2 to 6 times their breadth. The best proportion re-
mains quite unknown, because, if discovered, it would
evidently not be patenlatle, so that no private person
will make the requisite experiments.
As water and iron are the materials which nature
has provided for steam-engines, so is copper the mate-

Fz'g. 2061. GALLOWAY’S BOILER. (Cross Section.)
rial specially destined by its properties for boilers.
It is very superior to any other on account of its
almost harmless behaviour when destroyed by acci-
dents, and it is also cheaper than the material which
ranks next to it in economy, viz. iron, in at least the

ratio of 2 to 1. By this we mean, that, in order to


~ \ ___




___—_— T‘
‘v
'


:_-__-.
=_—--""-_. ___— -__-..—.-—- __-—"_‘__ ___—___—
_
produce a given quantity of steam, at .a given pres-
sure, during a given period, (long enough at least to
require one renewal of the material of the boiler,) in
a copper boiler, and to do the same also in. an iron
one, the expenditure of iron, and the labour on it,
will cost at least double the expenditure of copper
and the labour on it. It would seem, therefore, that
whatever might, by artificial anomalies, come to be
commercially the material best worth being used for
private interests, all boilers made by governments or
permanent public bodies would necessarily be of cop-
per. Such, however, is not the case in England,
even in war-steamers, and it is not worth while, in
this place, to inquire into the reasons why iron is
the material preferred. ' i
The highest pressures are the safest to use, because
every boiler must be made to bear, and be tested with,
a pressure exceeding in a certain ratio the greatest
which it is to be used with, or which the safety-valve is
to be loaded with. For example :——let ‘this ratio be
3 to 1; then the allowed pressure must be at least
tripled before the boiler can burst. But this is far
less likely to happen with a high pressure than with
a low. It is far less likely that the pressure will
suddenly increase from 3 atmospheres to 9 than from
1 to 3 ; far less likely that it will exceed the load of
the valve by QOlbs. than by 30 without opening it.
Experience confirms this evident truism, the classes
of engines using the highest pressures, viz. the Cornz'slz


.-._.__.._.—_____——_-..—_._________--. .__""__.__..___-_._____-________—_-—.___._.____-



\\\\\
Fig. 2062.
and the locomotive, havlng led to. the fewest ex—
plosions.
It should be required by law, that every boiler be
tested with air under the inspection of a public otiicer,
and the maximum pressure be stamped or cut on
some conspicuous part, (as is done at Birmingham in
the case of gun barrels.) It should further be required
that each boiler have two safety valves ;——but the
locking one of them up, out of reach of the attendants,
is a very questionable proceeding, since the effect
must be to relax their vigilance. The question is,
does the added security of one such valve outweigh
this? There is reason to think not, unless indeed a
fine were exacted for every time the “lock-up valve ”‘
opens. It was long supposed that for very high
pressures the safest preservatives were plugs of
fusible alloys, in different parts of the boiler, composed
so as to melt at the temperature corresponding to a.
pressure, say halfway between that stamped, and that

with which the boiler was tested; but simple plugs are
(Plan-J
rendered worthless by the very curious fact noticed
under BISMUTH, viz. that the plug of alloy, when
exposed for a length of time to a temperature near its
fusing point, undergoes a sort of eliquation by which
a more fusible alloy is melted out, and that which
remains is so, much ‘less fusible than the original alloy,
that in some exploded boilers the safety plugs have
been found entire. Enclosing the fusible metal in a
t/tz'n coating of copper (such as an electrical deposit)
might obviate this.
Locomotive engines. The first idea of a locomotive
mac/zine was a truly bold one. It was conceived and
carried out early in the middle ages, in the form of
various automata, some we are told even flying, by the
power stored in the winding up of springs. The idea of
a travelling locomotive (which might have been carried
out in the same manner, had men directed their atten-
tion to locomotion by means of railways) dates, however,
from a period since the general application of steam
to nearly all other mechanical purposes, and has only
726
STEAM-ENGINE.
been put in practice with steam power directly acting
and generated within the vehicle itself. That it would
only succeed with the most perfectly prepared ways,
or rather, guiding passages, might be anticipated,
though many fruitless trials with selfguidance on the
common English roads were at one period made.
But in the mining districts of England railways both
of wood and iron had long existed, and of these
(except the most minor class) it took possession, and
by its success, led to that enormous extension of such
roads, in number, scale and unprecedented costliness
‘of levelling, which has made the railroad and the
steam locomotive now almost inseparable ideas. [See
RoAns and RAILuoAns]
In 1804:, Richard Trevithick made and patented the
first steam locomotive, which ran on a railway at
'Merthyr Tidvil. It is remarkable how nearly, after
numerous changes, the newest have reapproached to its
arrangement. The cylinder was laid horizontally below
the front of the body or boiler, with its rod proceed-
ing backward and continued by another rod, jointed to
it, working the crank in the middle of an axle bearing
a fiy-w/zeel (necessary to all rotative and uncombined
or single cylinder engines,) and on the same axle two
cogged wheels, driving two others on the axle of the
hinder supporting wheels; by whose resistance alone,
against the rails, which were of iron, the engine was
urged along; drawing 10 tons in addition to itself at
the rate of 5 miles an hour. Seven years afterwards,
under the notion that the resistance between smooth
rails and tires could not be depended on to drive a
carriage, z'.e. that the wheels would slip round with-
out advancing, a racked or toothed iron rail and
driving wheel were patented, but failed from the
enormous wear and tear. A chain lying along the
centre of the road fixed at the ends and turning once
round a grooved driving wheel, with teeth catching
each link, by which the engine firrz'ed itself along,
was, as might be expected, still less successful; and
was succeeded by a truly ingenious expedient,
Brunton’s jointed propellers, made to imitate, behind
the carriage, the shape and action of the hind legs of
a horse, alternately lifted from and applied to the
ground by a very simple and frictionless arrangement
of joints from two cylinders laid horizontally as in our
modern locomotives. It was abandoned from a great
accident occurring in an attempt to use it on a
common road.
It was soon proved, however, that the weight of
an engine must always press its wheels to the rails
hard enough to ensure their advancing without slip,
even when drawing a train of considerable weight
besides. Still, to get the friction of four wheels
instead of two, Stephenson’s first locomotive had
the ‘two axles connected by an endless chain passing
round toothed wheels, one on each. But he in-
troduced the excellent and now indispensable principle
‘of using two cylinders and pistons acting on cranks
so situated, that when one is at what is technically
called one of its two dead points, nearest to or farthest
from the cylinder, and moving for an instant by the
mere momentum of the revolving parts, the other

shall be in the position that receives the fullest effect
of the steam ; or that when one piston is just turning
from stroke to stroke, and for the instant powerless,
the other shall always be at the middle of a stroke;
each engine following the other at an interval of half
a single stroke, (or keeping the position of the other’s
slz'de valve,) a principle now universal in both land
and water’ locomotors, and by which the flywheel is
dispensed with, because the joint motive power of the
two engines together remains practically almost equal
throughout a stroke. His cylinders were vertical and
over the two axles, their cranks being kept in this
necessary relation (viz. at right angles to each other)
by the endless chain making the two keep time
together.
The Stockton and Darlington iron railway, and
some of those on the Newcastle coal-field, had long
been travelled. by various locomotives, when the
Liverpool and Manchester railway company, having
completed that line, vastly exceeding all former roads
in amount of artificial levelling and high finish, offered
a premium of 500l. for the production of the best
locomotive, which, on the trial of four, in October
1829, was awarded to Mr. Stephenson’s “Rocket,”
whose attainment of 12% miles an hour with thrice
its own weight attached, and especially of 29 miles
an hour when alone, excited the utmost admiration,
and at once introduced the idea of railway travelling
(such roads having previously been regarded as only
for the carriage of goods) and excited that rage for
speed of travelling which has led in the 20 succeeding
years to the prodigious and incessant multiplication
of levelled roads of hitherto unimagined levelness,
cost and elaboration, for the sake of using similar
engines, since that time about doubled in capabilities
of speed, and trebled in compactness.
The one paramount requirement in a locomotive
engine being compactness or the production of a
maximum power in a minimum space, all other con-
siderations give place to this. Hence no idea of
carrying a condensing apparatus and supply of cooling
water has ever been entertained, but the steam merely
expelled from the cylinders into the air, as in high-
pressure engines of the simplest kind, as already
noticed under Fig. 2057, for neither can the principle
of expansion be practised, since the power has to be
obtained from the smallest vzae/a'rzerg/ that will afford
it, and not from the least fuel; or in other words, a
given cylinder must yield its utmost power, even
although this may involve the smallest data. And
the boiler being, as we have seen, the member whose
power is most absolutely dependent on its size, and
in a given bulk is limited by natural laws, it nece.»
sarily receives the chief attention, so that the problem
resolves itself mainly into the contrivance of a boiler
to evaporate the most possible water per minute or
hour, in the least possible space; with how much
fuel is quite a secondary consideration, since thiscan
‘be carried in a separate vehicle, and its economy is
a minor affair in fulfilling so purely artificial a want
as that speed of transit on which the p esent ‘railways
and machines of this class depend.
STEAM-EN GINE. s27
The principle introduced by the “ Rocket” boiler,
which constituted the superiority of that engine, and,
carried still further in all later ones, may be said to
have made the present railway system, is that of
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K
CROSS SECTION THROUGH THE FIRE-BOX Ol-
cnamr'ron’s LOCOMOTIVE.
carrying the hot products of the fire through the
water by numerous small parallel flues or rather tubes;
thus dividing the heating matter, and, as it were,
filtering it through that to be heated; immensely
multiplying the
surfaces by which
they communi-
cate, and at the
same time bring-
ing the heating
and heated fluids
Fig. 2063.

The locomotive boiler now always consists of a
cylindrical body laid horizontally, with flat and
vertical ends, and a nearly cubical addition, of its
own breadth, depending from the hinder end; i.e. we
may consider the lower half of the cylinder, for a
length nearly equal to its breadth, replaced by a cube,
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Fig. 2064. LONGITUDINAL SECTION on THE SAME.
which of course hangs down about half its depth
below the belly of the unaltered part of the cylinder.
This cubical part encloses the fire-box, nearly filling
it, and extending partly up into the semicylindrical
arch above; and Figs. 2063 and 2064, represent the
two vertical sections of this part in the fine engine of

nearer together,
because the
small diameter
of these tubes
enables them to
be proportionally
i/zinner, the pres-
sure a cylinder
will resist de-
pending, not on
its absolute thick-
ness of solid wall,
but on the pro-
portion thereof



to the whole dia~
meter. Thus the
water and heating gases are, by a sort of rude ap-
proach to the mechanism of an animal’s lungs, minutely
divided and presented to each other, like the air and
the blood, at as many points, and with as little inter-
vening matter as is consistent with their separation.
Fig. 2065.
CROSS SECTION 01’ THE SAME THROUGH THE MIDDLE OF THE BOILER AND CYLINDERS.
Messrs. Crampton’s whose side elevation is given in
a steel engraving. In Fig. 2063, it is cut by the
middle plane of the locomotive, and in Fig. 2064, by
a plane crossing it through the fire-box. Fig. 2065,
is another cross section through the round part of the
728
STEAM-ENGINE.
boiler, about the middle of its length, and the same
letters apply to all. The fire—box, it will be seen, is
double walled, or rather walled and roofed with a
layer of water, leaving only‘ the bottom vacant which
receives the grate bars 51. In many engines a plate
of iron descending from the back, or‘ wall containing
the fuel door cl’, bends under this grate as an ash pan,
and, by the sides also continuing down, encloses a
lower chamber, open only in front, that the forward
motion of the engine may oblige the air caught in this '
receiver to pass up through the fire and create more
draught the more it is .wanted. The two plates enclos-
ing the water walls of this box are everywhere qaillccl
together by the long rivets a a, &c., as the sides of a
mattress by stitches. But a large portion of the for-
ward face is not thus double, it being included in the
cylinder of the boiler. This, then, is held from collaps-
ing on the fire, by the numerous tubes above mentioned,
ill, &c., which are thus stays as well as fines, going
straight through the length of the body of the boiler,
and tying together its two flat ends so as to prevent it
from bulging. But above the top of the fire—box
other stays are wanted for this purpose, still longer.
and these are furnished by the solid rods 0 c c, which
proceed from end to end of the entire boiler, fire-
box included. Lastly, the fiat ceiling of the fire-box
(which cannot be raised higher because it must be
kept well covered with water) is sustained by bolts
passing up through the deep cast-iron joists 666,
The mode of taking the steam from so moderate
a steam-space as is left in the upper curve of this
boiler, without admitting the fine spray or mist
carried up by the violent boiling, or even water
splashed over by the motion of the vehicle, has
undergone many changes. Often an erection called
a steam-dome serves to cover the top of the steam-
pipe which, within the boiler, turns up and receives
the steam by an expanded mouth like a chimney
raised to nearly the top of this dome. In the present
engine a tube s s extends along the whole back of
the boiler, and collects the steam by a line of long
slits on its upper side. The centre of its length com-
municates with the box 0, from which descend the
pipes e e to the valve-boxes of the cylinders 66, and
the eduction pipes from these same boxes go forward,
as seen in the elevation at ‘a, and turn into the smolcc-
6ow. This is a cylindrical addition to or continuation -
of the front end of the boiler. Into it the nume-
rous tubes ll pour the products of the fire, and from
it the chimney ascends. The cylinders are, in many
engines, placed in a downward enlargement of this
box, the better to confine their heat 3 and in all cases
their used steam is brought here and made to issue
upwards from a tube tapering to a mouth like a jet
directed up the chimney. This is called the 6laszf,
and has an important effect in increasing the draught
through the fire.
The cylinders, however placed, always act- in the
simplest'and most direct manner on the driving axle,
by the piston rod i, which slides between guides, and
the crank rod ls, working the crank l, in this case
outside, but often inside the wheel. Outside of this

again, is the excentric n, whose rod works directly,
but by a peculiar connexion, as will be seen, the rod
s of the slide valve in f The feed pump, each side
having one, is in this case placed at a: in a line with
the axis of the cylinder, and the piston-rod being
prolonged through lot/z, ends of the cylinder (evi-
dently an advantage wherever it lies horizontally),
its front end forms the plunger of the pump. This
draws its supply up through a ball-valve from the
pipe :22’ x’, whose hinder end is coupled by an ingenious
yielding joint to a pipe descending from the tender.
What the plunger has thus drawn, it impels up
through another ball-valve into the pipe a", by which
it enters the boiler. Thus the whole of the propelling
machinery, or that worked by the steam, is as simple
as any steam apparatus can well be conceived.
The remaining functions, necessary to the manage-
ment, or which must be performed by the hands of
the driver, through proper mechanical aids, are seven.
1st, regulating the pressure of steam; 2d, regulating
the supply of steam to the cylinders (which includes
of course starting and stopping); 3d, regulating the
generation of steam, ale. the rate of combustion in
the fire; 4th, regulating the supply of water; 5th,
reversing the order in which the slide-valves produce
the strokes, and thereby the direction in which the
wheels revolve; 6th, letting water out of the cylin-
ders; 7th, sounding an alarm.
The object, then, being to bring the handles for all
these seven operations within reach of the driver
standing behind, there are almost countless varieties
of disposition for these details, but in the present
instance we have (1) the safety-valves both situated
on the cupola a, one looked up, the other governed
by a lever, of which the end is held down by the
spring balance 6, similar to those used for weighing
with a straight scale, (not a dial.) It is evident that
by turning the nut that holds down the valve-lever,
the screw seen above will be lifted through it, and
the spiral spring stretched upward, and kept extended
by a strain, which, as soon as the upward tendency of
the valve enceecls, it will open by extending the spring
still higher; and the amount of this strain is seen by
the scale. 2. For regulating the supply of steam,
the horizontal wheel turned by handles clcl, pushes
forward or withdraws the long red passing into the
box 0, where its end moves (as seen in Fig. 2065)
a pair of shutters sliding over the apertures of the
steam-pipes e e, these shutters being pressed apart by
a cushion of steam. 3. The intensity of the fire is
regulated by altering the aperture of the blast of
used steam in the chimney, which is the chief source
of the draught throughout. To this end the blast
pipe, which is formed by the meeting of g with that
from the opposite side, terminates just above jj in
the form of ahollow wedge, of which the two inclined
' sides turn on axes at their feet, which axes, coming
out of the smoke-box, appear at jj, but these two
plates are pressed together like lips at top, by springs.
Close to the driver’s right hand, but hidden here by
the upper part and guard of the driving-wheel, is
a winch, which, by turning a large screw, advances



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STEAM-EN GINE—STEAM- NAVIGATION.
729
or withdraws through a short space the long rod
j’j’, which, it will be seen, moves a short arm descend-
ing from the first j, and another arm therefrom
similarly affects the second j, so that the two plates
turning on j j as centres are simultaneously ap—
proximated or separated from each other at top,
regulating the aperture as required. 4.‘. For the
regulation of the supply of water, first the size of
the feed-pumps is made such as to supply, when
left alone, more than can ever be required under any
circumstances. Next, a cock of variable aperture
is placed where the feed pipe :e" enters the boiler,
and governed (that of each side separately) by a
simple gear not here visible; and then a small reinrn-
pipe is carried from near this cock down to the pipe
re’, by which all the feed-water would return and
never enter the boiler, were not the entry to the
return-pipe made to be more or less closed by the
same cock that enlarges or reduces the aperture into
the boiler. l/Vithout this pipe it is evident that the
mere reduction of the entry to the boiler could not
reduce the quantity injected per stroke, but only im-
pede the engine by its resistance, until the pipe a”
burst, which it mnsl do if without escape for the com-
pressed water. 5. The gear for reversing the course
of the engine is by far the most elaborate, and that in
which most variations have been used. The principle
is to have always i200 excentrics for working each
valve-box, one to be used in travelling forwards, the
other in backing, and of course fixed on the axle with
their greatest projections in opposite directions, as
seen at n and 0, best in the separate figure which
represents the reversing gear alone. It is evident
that when the rod of one, p, is withdrawn, that of the
other, g, must be thrust forward, and nice verse’, so
that they would contrarily work the slide; one
making it to preeerle the piston by half a stroke, and
the other to follow it by the same interval. The
problem is how to transfer the slide-rod s from the
influence of one of these to that of the other, without
a shock. It is here effected (as in the most modern
engine), by a kind of link r connecting the ends of
the two excentric rods p q, and in which link the head
of the slide-rod 8 may slide to or fro. This rod s,
however, keeps always in the same straight linefand
it is the ends of r or of the excentric rods p g, that
must be successively brought to it‘, and not it to ilzenz,
to place it under the governance of a fresh excentric.
For this a chain of levers is used, beginning at the
lever e, which has a handle at the top, and its ful-
crum at a horizontal arbor or axle n. Pulled back
into the dotted position, its lower end, below a,
thrusts forward a nearly horizontal bar, seen jointed
at its end to a short arm from the second arbor or
axle i‘, which is thus moved similarly with n, about
a quarter round. This arbor, extending all across the
carriage, bears near each end such a lever as that
to which the weight 20 is attached. The action of
pulling back a, it will be seen, lifts re, and depressing
the other end of its lever, draws down by a connect?
ing bar the top of the piece r, together with the
whole triangular assemblage formed by p g and r,

which must move together, preserving their relative
positions. It brings down p into nearly the absolute
position commonly occupied by q, thus making p
instead of g the governor of s, and reversing the
motion of the slide, and hence of the whole engine.
But in this movement the head of s is successively in
every part of the length of r, so that the change is
gradual; and could we stop exactly when the head of
s is at the middle of r, the slide would not be worked
at all, the middle of r keeping always at the same
distance from the axle, because one of its ends is
always as much thrust forward as the other is drawn
back, by the exactly contrary motions of p and g.
The next want, that of draining the cylinders from
time to time of any water that might accumulate in
and endanger them, is accomplished by small cocks
gg at each end of them, all four connected and
opened at once by pulling up the rgd g’; and for the
last, a noisy signal or alarm, the steam-whistle a, con-
sisting of two hemispheres or bells, mouth to mouth,
and a flat disc between and nearly touching both, has
been found effective.
STEAM-NAVIGATION. There is evidence that
the propulsion of vessels afloat was the first useful
purpose for which any one attempted to store up the
power of steam; and the first (except that of military
projectiles) to which fuel-power, or the motive effect
of combustion, was ever applied. In 15ét3,before mo—
derns had thought of settling by experiment their
notions of the simplest laws of matter and motion,
and consequently before their physical knowledge had
made any advance beyond that of Ptolemy and Here,
(some seventeen centuries arrested by false learning,
it is recorded that one Blasco de Garay effected, at
Barcelona, the propulsion of a boat, without sails or
cars, by an apparatus, of which a large lcelile Qf boil-
ling water was the chief feature. As the “ Pneu-
matics" of Hero preserved the memory of various
toys and automata moved by the reaction of issuing
jets of steam, it seems likely that the effect of such
a jet or jets directed backward from a boat into the
water would be tried; and such, we fancy, must have
been the nature of Garay’s steamer, involving as it
does no moving machinery, nor so much as Worces-
ter’s or even Galileo’s acquaintance with the pro-
perties of elastic fluids.
Worcester does not mention this among the possible
uses1 of his grand discovery; but every succeeding

(1) Some have imagined that he did so in one of his inventions
called the “ quintessence of motion,” by which he boasts that he
could “ make a vessel of as great burden as the river can bear, to go
against the stream, which, the more rapid it is, the faster it shall
advance.” This dependence on the speed of the current, how-
ever, clearly shows that the current, and not any artificial mo-
tion, was his prime mover. Of course his propelling apparatus
must have acted not against the water, but against the ground;
and, with this proviso, it would be as possible for the current to
move bodies against itself, as we daily see it is for the wind to
urge sailing vessels against itself. The comparatively motionless
fulcrum which, in sailing, is furnished by the water, would in the
other case be afforded by the bottom or banks; nor can we see any
reason why the power of rivers should not thus be used to trans-
port goods up as well as down the stream, now and at any future
time, with as much saving of human labour as this far-sighted
philosopher anticipated.
730
STEAM-NAVIGATION.
advocate and improver thereof, from Savary and Papin
downwards, makes special allusion to it; proposing
generally to efi’ect it by the present commonest form
of propeller—the paddle-wheel. Thus steam-naviga-
tion has been, among the scientific, quite as old a
project as the steam-engine, if not older, only waiting
the attention and enterprise of wealthy men for its
‘realization.
Before l/Vatt’s invention of the double-acting
engine, the dilficulty of getting a confirmed mo—
tion, 2'. e. a rotation from steam, led to various expe-
dients for using the intermittent motion of the
atmospheric piston, by applying it to propellers more
easily moved by it than the wheel, which was yet
allowed to be abstractedly the best. Dr. John Allen,
in 1730, was the first proposer of the pzmzp or bellows
mode of propelling, z'. e. by forcing out a stream of
water or air in the contrary direction to that in which
the vessel is to advance; a method which has since
been the subject of numerous patented failures.1 But
Jonathan Hulls, in 1736, not only most logically and
satisfactorily demonstrated the practicability of steam-
navigation, but planned a steam-boat, itself quite
feasible, and as near our present ones as any driven
by atmospheric engines could perhaps approach. Two
such engine-cylinders are placed abreast, as at present,
and their pistons suspended by cords or chains pass-
ing over pulleys to the stern, beyond which a frame
projects, and carries one large paddle-wheel, like an
undershot waterwheel. Near the two ends of its
axle are two small wheels, round which the said chains
make one turn, and then hang down and end in
weights suflicient to draw up the pistons. These two
wheels are loose on the axle, and connected with
the paddle-wheel by a ratchet-wheel, so as to oblige
it to turn with them in one direction, but not in the
other, (as the ratchet-wheel enables a clock or watch
to be wound up without turning its hands, though
the same axle cannot turn the contrary way without
driving them.) The pistons being pressed down
alternately, would each drag round the axle and
wheel through a certain space, and then leave it to
be drawn round an equal quantity by the other
piston, while the first was pulled up to the top
of its cylinder by its counterweight; thus imparting
between them a continued rotation to the paddle-
whcel; which might even have been made quite uni-
form by having three pistons instead of two, and
making the connexion by cranks 120° apart, as in
Watt’s second proposal for rotation. But this mode
of “ carrying ships out of or into any harbour, port, or
river, against wind and tide or in a calm,” although
patented for 141 years, was far too advanced beyond the
general knowledge of the time to be then introduced.

(1) This stream has always, we believe, been tried single, and
from the stern, although the natural exemplars of it, the gills of
fishes, (certainly auxiliary to, if not principally concerned in, their
propulsion,) are on each side, and, like our paddle-wheels, ahead
of the centre of gravity, and a little ahead of the widest beam of
the animal. Has this mode of propelling, after all, had its fair
trial? If capable of competing with others at all, it evidently has
some great advantages over all of them—in the freedom and inde_
pendence of the evolutions which it would render easy, even
without the rudder.

The celebrated mathematician, Daniel Bernouilli,
afterwards turned his attention to the subject, and
seems to have leaned to a kind of artificial fins, con-
stantly under water, which have never been fairly
tried.
In 1757 this problem was made the subject of the
prize offered by the French Academy, which was
awarded to the said Bernouilli for his demonstration
of the use and efi'ect of paddle-wheels, and other pro-
pellers to be moved by the expansive force either of
gunpowder or of steam. No practical trials, however,
followed. A Swiss clergyman named Genevois failed in
some attempts with imitations of a (Zuclr’sfoot‘; and
the matter then remained in abeyance for about 20
years. After this a variety of serious attempts, at
considerable pains and expense, were begun; three
successively in France by the Comte d’Auxiron, M.
Perrier, and the Marquis de J oufi‘ray, all of whom
succeeded in producing a slow propulsion, and the
last built a steam-boat on the Saone no less than 147
feet long: his experiments were, however, interrupted
by the Revolution. The attempts of M. Seratti in
Italy, and of James Ramsay, John Fitch, and Oliver
Evans, on different rivers of America, were less
successful. Watt’s rapid improvements of the engine,
however, then completed, ensured to Britain the
glory of constructing the first profitable steam—vessel,
which was done by William Symington, a Scotch engi-
neer, at the instigation and expense of Patrick Miller,2
a gentleman of Dalswinton, near the Forth and Clyde
Canal, on which this boat ran, at first, in 1788, at the
rate of 5 miles an hour, and afterwards, with larger
paddle-wheels, attained 7 miles an hour. Another,
called the “ Charlotte Dundas,” was constructed in
1801, and continued in use on the same canal many
years, as a tug, capable of towing at once two vessels
of 7 0 tons each.
Meanwhile, the attempts of the three Americans
above-named all failed to attain a profitable speed ; as
did that of Earl Stanhope with a revival of the artificial
duck’s-feet; and that of Fulton, another American,
then residing at Paris, where his first boat broke under
the weight of its machinery, and a second, built in
1803, could not attain a useful speed. This Fulton,
however, going the same year into Scotland, saw the
“ Charlotte Dundas,” was taken a trip in her by Sy-
mington, and received from him a full explanation of
her machinery, which he minutely examined, noted, and
questioned Symington upon. “I considered,” says that
engineer, “the more publicity that was given to any
discovery intended for general good, so much the bet-
ter; and having the privilege secured by letters pal ent,
I was not afraid of his making any encroachment
upon my right in the British dominions, though in the

(2) The war between France and England led to various pro-
jects at that time for propelling rafts or transports, with head to
wind, or in a calm; and this Mr. Miller, after proposing to do so
by paddle-wheels driven at first by the crew working at capstans,
and afterwards by windmills, was led at length to think of steam-
power; but had no share in the contrivances for applying it,
which seem jointly due to Symington and Henry Bell (afterwards
referred to) who assisted him without sharing either the honour
or the profit.
STEAM-NAVIGATION.
731
United States I was well aware I had no power of
control.”
Having ordered an engine of Boulton and Watt,
(it is said under an assumed name,) Fulton proceeded
to America, and with a capitalist, named Livingstone,
obtained there a patent for what he called his inven-
tion (not introduction) of steam-boats. They then, by
the aid of drawings and advice gratuitously tendered
them by Mr. Henry Bell, an Engish engineer who had
also assisted Symington, built a vessel to receive the
engine ordered of Boulton and Watt; and in 1807,
eighteen years after Symington’s triumphant steaming
of seven miles an hour at Dalswinton, this American
celebrity made its first trip on the Hudson river,
attaining barely five miles an hour. The State of
New York had offered, as a prize, the monopoly of
steam-navigation in its territory, to the first who
should propel a vessel in this way four miles an hour,
and a native engineer, R. L. Stevens, had contrived
one which, only a few days after Fulton’s, achieved
equal success. A greater honour, however, than the
expected prize, fell in consequence of this to Stevens’s
vessel; for being thus debarred the use of it in that
State, he had the boldness to proceed to Delaware by
sea, thus making both the first marine and the first
ocean steamvoyage, many years before any one else
ventured to steam out of rivers, and 32 years before
ocean steamers were thought practicable.
Peace, and the travelling propensities of a nation of
refugees settling far apart along boundless rivers,
caused the commercial value of steam navigation to be
immediately realised in America, so that two more
boats were commenced by Livingstone and Fulton
even before the death of the latter in the following
year; and Stevens soon made such improvements as
raised the speed attainable to 13 miles an hour; cle-
velopiug the mode of connexion between the pistons
and cranks still most used in America; and even one
improvement, that has not yet been adopted in Eu-
rope, the division of each paddle-board into 3 or more
portions arranged like steps, to obviate the shock of
a whole board entering the water at once. Meanwhile
in Europe, even in Scotland, the invention lay neg-
lected, and it was, as it were, reintroduced and almost
regarded as an American one. Nor was it, until the
year 1812, that the first passage-boat was made to
ply on the Clyde, and so little was the power of en-
gine necessary to propel a large vessel then under-
stood, that it was only of 3 horse-power. It became
soon evident that, to attain any useful speed, the en-
gines and boilers must occupy a very considerable
portion of the vessel; and, to save room, all condensing
apparatus was omitted, and the high-pressure steam
allowed to escape at each stroke, as in locomotives,
and in many steamers in use to this day in America,
where the economy of fuel is a minor consideration
to that of space and machinery. As improvements
were made in compactness, however, the condensing
apparatus became universal in English steamers. The
first sea~going boat was established in 1815, between
Glasgow and London; and in 1817 the number of
such boats had increased sufiiciently to call for legis-

lation against accidents, which had already been more
numerous and destructive in England than in the
whole time in which steamers had been multiplying
in America. The regulations then made were to the
effect of forbidding all use of cast-iron in boilers,
(which had hitherto been made often wholly of that
material, to avoid the difficulty and expense of rivetting
numerous seams,) requiring them to be tested when
first made, with a pressure of water; and to have 2
safety-valves, one open to the engine-driver and all per-
sons on board, the other visible, but inaccessible, and
loaded with no more than l-third of the pressure with
which the boiler was tested, or 1-sixth of what it is
calculated, from the data of the strength of the mate-
rials, to burst with. These laws are still incomplete
in fixing no minimum time for the continuance of the
testing pressure (which may not effect what a far
lower pressure might do in a longer time); in re-
quiring no periodical trial of the locked-up safety-
valve, and especially no periodical re testing of the
boiler as it progressively wears and corrodes, and be-
comes weaker from day to day; and in fixing no
minimum size of safety-valve relatively to that of the
boiler. Neither will leaden or fusible safety-rivets be
common unless enforced by law, nor effectual unless
obliged to exceed a fixed size; nor will boilers be
tested with air (a far different trial and closer imi-
tation of what they are to bear habitually than the
pressure of water, only tending to expand into a thou-
sandth or lO-thousandth more space); nor will engine-
drivers be fined for the steam showing, by opening
the locked-up valve, that they have overloaded or neg-
lected the accessible one.
The good effects of such enactments, however im-
perfect, have yet been shown in the proportion of
English to American accidents becoming ever since
that regulation exactly reversed, so that there are
now ten passengers killed in America to one in
England.
After Henry Bell, the joint originatol with
Symington, and the reviver in 1812—13 of British
steam~navigation, Mr. David Napier contributed most
to its improvement. He introduced the mode of con-
nexion most common in Europe, called the stale-lever
connexion, and was the first to succeed in forming
condensers without injection, the object of which was
to enable sea-going steamers to use fresh water, the
same fluid circulating through the boiler, engines, con-
denser, and feed-pump, without admixture or loss.
By this means, the hard incrustations deposited by
salt-water in the boilers would be obviated; but the
plan does not seem to have been yet made perfect
enough to be extensively used, for Watt’s mode of
condensation is still almost universal.
The triumph of steam-navigation may be said to be
completed by the establishment of regular trans-
oceanic packets. Although the Savanna/z, a 800 ton
American steamer, came to Liverpool in 1819 and re-
turned, and although the _Onrocoa in 1829 made two
voyages between Holland and the “Test Indies, both
depended chiefly on their sails. It was just a century
after Jonathan Hull’s neglected proposition, and half
v7'32
STEAM-NAVIGATION.
a century after S'ym'ington’s first realization of it,
‘that the first keel was laid expressly for an Atlantic
steam-ship, the Great Westera of Bristol, which in
April, 1838, crossed to New York, and‘in May re-
turned; preceded at an interval of three days by the
Sirius, of Liverpool, a vessel not built for but adapted
to this new service; each having peiliformed without
supplies above 3,000 miles, at an average rate of
210 miles a day. The Great Western consumed
655 tons of coal on her way out, which was 3125
miles in 17 days; and 392 tons on her way back,
which was 3192 miles in 15 days.
There is a great

Fig. 2066.
preponderance of westerly winds, it will be re- '
membered, throughout
l Atlantic.
Until within these ten years, only one general form
of propelling apparatus had been used for all steamers,
the temperate zone of the

Tunmu

.‘ll
ETETHJ
11.12171"!
_ 161722067. LOKGITUDINAL SECTION, snowme one CYLINDER
AND cum OF THE “SIDE-LEVER” meets-Es.


cnoss SECTION THROUGH A “sine-LEVER” STEAMER.
vessel from the head. 'To diminish the extreme
width, the vessel is often contracted, like a wasp’s
body, at the part crossed by the shaft. The whole
axle rests and turns on 8 bearings, those for its ends
being in the overhanging frames that carry the
paddle-boxes, the next two in the sides of the vessel,
and between these are four other hearings, on iron
frames rising from the bottom of the vessel, where
they stand on four very stout beams. laid longitu-
dinally, marked 1) 1) D 1) in Figs. 2066 and 2067, which
serve to distribute the weight of the machinery over
a great number of the ribs of the vessel; the diffi—
culty of a sufiicient foundation, which was greatly in-
sisted on by those who ridiculed steam navigation,
throughout the half century of its invention, being
really far less formidable in a boat on the equable
support of water, than in any circumstances on land.
Between the first and second of these frames, reckon-
ing either way from the centre, the axle is interrupted
to form a crank, so that these divide it into three
pieces, called respectively the two paddle-s/zq/ts and
the intermediate slzafl; and the two cranks are in
planes at right angles to each other, as in a locomo-
tive, in order that the action thereon of the two
pistons, however communicated, may keep up an
equable rotation, by each being in the middle of its‘-
stroke when the other is changing its motion. So far
_ and is still by far the commonest. It consists of two ' all paddle Steamers are alike, and we may add that
,paddle—Wlleels, fixed on the outward projections of . (although we have seen a small American steamer
.one great shaft or axle, crossing the vessel at or a uith the cylinders laid horizontally) the cylinders are
little below the level of the spar deck, and at from . so much better vertical than in any other position.
two-fifths to not quitelhalf the extreme length of the l that their verticality may also be regarded as an uni-
\
‘STEAMsNAVIGAzTION .
733
versal character; and they stand of course in the
planes of revolution of the two cranks, or equidistant
on each side of the middle plane of the vessel; though
sometimes before, sometimes abaft, and sometimes
directly under the cranks, according to the means
used for imparting their motion thereto, which forms
the sole element of variety in paddle—driving engines.
To place the cylinders under the cranks, and carry
a connecting-rod from the head of each piston-rod to
the crank, (in fact, the propelling parts of a locomo-
tive, only placed upright instead of horizontal,) has
only answered for very slow vessels; because, as
there must be height above the cylinder for, first‘,
a piston-rod of its own length, tben a connecting or
crank-rod at least as long, (and the longer the better
for uniformity of motion,) the length of stroke can
evidently he never more than one-third the height
from the ship’s bottom lining to the top of the circle
described by the crank; or, we may say, one-third of
her inside depth, because, although the crank rises its
own radius, or half the length of the stroke, higher
than the axle or deck, the depth of the foundation
beams D, and of the stuffing-box, cylinder-ends, and
junction of the piston and crank-rods, will always
more than measure this half-stroke. Now, two en—
gines of the usual proportions, and no longer a stroke
than a third of the vessel’s inside depth, are quite in-
adequate to give it, with the usual pressures of steam,
the velocity now required by the public in steamers.
Some more circuitous connexion, then, is almost
universal. The above is called a “ direct-action”
engine, and properly should be the only one so called;
but the name is extended to all that have no lever of
the first kind (see STATICS) interposed between the
piston and the crank, i.e. all in which they both rise
or fall at the same time. Thus all engines become
divided, as regards this, into direct-action and beam
engines; of which we will first notice the latter,
because they were the first used, and are still the
commonest in large and important vessels.
These are again subdivided into those whose beam
or lever is above the crank, as in land-engines, [see
STEAM-ENGINE, Figs. 2039 and 2053,] and those in
which it is below, as about to be shown. The former
are exclusively confined, or nearly so, to America, and
are commonly called beam-engines. The others, having
to each cylinder two beams or levers placed as low
as may be possible, one on each side of it, are hence
called side-lever engines, and are still the commonest
in Europe, at least for large vessels. In these a
cross-bead is necessarily placed on each piston-rod,
projecting each way beyond the sides of the cylinder,
and from its ends hang the two rods that work these
beams, while the further ends of the beams are
united by a cross-tail from which ascends the rod
that works the crank. At first sight, this, although
having more parts, would seem to be greatly superior
to the American arrangement, which exposes its
beams with all their joints and appendages aloft to
the weather. But it must be remembered, that the
proportion of the stroke to the depth of the vessel is
here still limited, as there must be depth for at least

the whole length of the crank-rod below the crank
when in its lowest position; whereas the American
plan exacts only depth for the crank itself to revolve,
and is thus suited to the very shallowest vessels, or
those approaching the nature of rafts. Although a
most inartificial expedient, therefore, something like
leaving part of an animal’s machinery outside his
skin, it cuts the knot or evades the difficulties of
contriving a good steamer; and must obviously con-
tinue to possess the shoaly and uncertain rivers of a
new and unimproved country.
The common European or side-lever machinery is
shown in Figs. 2066 and 2067 ; the former a longitudi-
nal section through the keel, the latter across the space
left on that side of the axle farthest from the cylin-
ders or engines, (as they are commonly called,) which
may be either before or abaft it. When before it, they
oblige the steam-pipe to be conducted from the
boilers (which are always aft) through the whole
space occupied by the machinery, but we have shown
it simply entering one engine at n. The steam passes
round on each side the cylinder by the encircling
hollow belt J, partly serving the purpose of the
jacket, to arrive at the valve-box v. The sliding
kind of valve is universal, and always moved by an
excentric-rod from the axle as here shown, separate
excentrics of a different shape called cams being pro-
vided for regulating the grade of expansive working.
[See STEAM—ENGINE] The used steam descends into
a condenser below w, in a water—tank ; and the air-
pumps, one for each engine, are at AA, each con-
nected with the two beams 38, in just the same way
that the working piston itself is, by a cross-head,
from the ends of which‘descend rods to that point of
each beam which describes the properly diminished‘
stroke. The cross-head H of each engine (and some-
times that of each air-pump too) is kept in one:
vertical plane by the peculiar kind of parallel motion
seen at P, composed of a long and a short arm, the
short one attached to a fixed point. This, of course,
is repeated for each end of each cross~head. The air-
pump expels the hot water into the well w, whence
the feed-pump (too small to be represented in the
figure) draws its supply.
It is evident that in these side-lever steamers, the
length of stroke relatively to the vessel’s depth, (and
consequently the proportion of power to size, and
hence the speed,) is limited only by the necessity of
depth below the crank for its rod c c, which must be at
least as long as 1-12- times the stroke (or diameter of
crank circle), to give a tolerably uniform motion.
There are many contrivances for placing the cylinders
under the shaft, -and yet avoiding much more (or
even any more) limitation than this; and all such are
usually called direct-adieu engines, of which we will
now notice the chief.
I. The piston-rod may ascend, when highest, even
into the hollow of the crank, i.e. above the level of
the axle, if we place on its head some horizontal cross
piece as on a T, lying fore and aft, and projecting
further each way than the circle described by the
crank, and then raise from its ends two rafter-like
734
STEAM-NAVIGATION.
pieces extending to any required height, and from
the top where they meet, suspend a rod to the crank,
which will thus be worked from above, though the
cylinder is below it. This arrangement is called the
steeple-engine, from its high and pointed form. It
gives an awkward, top—heavy impression, from the
great apparent mass lifted bodily above deck at each
stroke; which may account for its infrequent use,
although it really saves, or may save, more depth
than any except Messrs. Maudslay and Field’s doable-
pistoii-rod arrangement. It requires the verticality
of motion in so large a mass to be insured by guides,
against which friction-wheels should roll.
II. The doatle-pisloa-rod engine, above alluded to,
although one of the latest inventions of its eminent
authors, is simply a refinement on the above. As
there are two piston-rods to each piston, the centre
of the cylinder-cover is plain, and this allows the
crank when lowest to barely clear the said cover,
thus saving, as compared with the “ steeple,” the
depth of a stufling-box, and also of the '1‘ head, form~
ing the base of the triangle or steeple, which piece
requires some depth, as it resembles a scale-beam,
supported in the middle only, and loaded at each end
only. Messrs. Maudslay and Fields two piston-rods
are near the sides of the cylinder, but neither on its
fore and aft diameter, nor on that crossing it, although
nearest to the latter, as near as they can be to clear
the axle which passes between them. The oblique
position is evidently necessary, in order that they
may interfere neither with this, nor with the revolutions
of the crank. The whole is the shallowest arrange-
ment possible without a beam above deck, and has
accordingly been adopted on such shoaly rivers as
the Rhone, the Indus, and thea'Sutledj.
III. The oscillating engine was the capital inven-
tion of Mr. Goldsworthy Gurney, but decried and



way-5“ \\\\\ ‘ '
afiqgw
neglected until it was introduced into boats by Mauds-
lay about 20 years ago. As seen, in Fig. 2068, the
Fig. 2068. OBCILLATLNG cxmnnnn.

piston-rod is made to serve also as connecting-rod,
its top embracing the crank-pin. As this must, in
such case, describe a circle, the rod moving it must
be allowed an angular vibration to and fro, as we see
in all crank-rods. To permit this in the piston-rod,
the whole piston and cylinder must be allowed to
partake in the oscillation, which is done by support-
ing the cylinder solely on 2 trzmriiorzs, like those of a
cannon or a transit telescope, one of which is seen at
8. Of course the steam can only enter and leave it
through one or both of these trunnions ; therefore it
must be directed thence to the ends of the cylinder
by passages and valves all moving bodily therewith,
independently of the proper motions of the valves.
This is accomplished commonly as here shown, by the
valve-box v v being screwed to the side of the cylinder,
and its rod moved by an arrangement conducting
motion from an excentric on the fixed axle. All this,
however, is needless, as properly placed openings in
the hollow trunnion s, and the cylindrical surface in
which it turns, would answer all the purposes of valves,
valve-boxes, valve-rods, valve-gear, and excentric,
and by thus admitting the steam through one trunnion,
and exhausting it through the other, we should have
probably the very simplest steam-engine (as regards
the number of parts and the amount of workmanship)
possible. Its moving parts need scarcely contain
10 pieces exclusive of screws, nuts, &c., the passages
being cast in one with the cylinder, as the steam-
belt BB and the trumiions always are. The depth
required below the axle here is evidently once and a
half the stroke. It is not therefore so compact as the
“steeple” forms, but it has the advantage of re-
quiring less framing, and distributing its weight
better than probably any other form of engine.
There seems still much timidity in extending the
use of this excellent form beyond the smallest class
of marine engines. Mr. Bourne, in his “ Catechism
of the Steam-engine,” gives it the preference over all
other engines, not only for sea, but for all land pur—
poses, including locomotives; and if well proportioned
and simplified, it would seem not unlikely to super-
sede them all, except in works of great magnitude,
perhaps even in those. In the application of this
engine to boats, one air-pump, large enough for both
engines, is placed between them, and worked by a
third crank in the middle of the axle.
IV. A doable-cylinder arrangement, (that is, having
2 cylinders to each crank,) Eig. 2069, has been em-
ployed by Messrs. Maudslay and Field in their largest
steamers, whose power is perhaps such as, to obtain
from 2 cylinders only, would need a magnitude hardly
yet attainable. The valve-box it is common to two
cylinders, as seen in Fig 2070, a plan of the pair on
one side of the vessel; and its slide is worked directly
from an excentric on the axle just over it. A small
passage is always open at in from one cylinder to
the other, both at their top and bottom, to insure
equal pressure in both. The piston-rods t t bear
two T or Y-shaped pieces 6 a, between which the
crank-rod f ascends from their foot d to the crank.
In the example whence the figure is taken, the cm
‘' STEAM-NAVIGATION. A
735
nexion occupies much more height than is necessary.
It will be seen that the limitation of stroke relatively
to the depth of the vessel is nearly as in the “ steeple ”
engine, the pieces c 0 however admitting such a for—
mation as to allow the crank to descend when lowest
to a level with the tops of the stuffing-boxes. Rods
/_'_-~
/// \


};\\.‘€\\)-\\\
m‘k \.
n
kkhl












_ l
in I‘
llttttl
lllllllll 1'
5W
;
l
_l
s;
_llllll


Figs. 2069, 2070. SIDE nLnvAuoN AND PLAN or one ram or
MAUDSLAY’S nounnacrmnnna nnenrns.
ascending from the 2 sides of cl work ‘the 2 levers,
from whose united ends the rod of the air-pump 2'
depends, and from other points the feed and bilge
pumps.
V. A still more compact invention of the same
artists, the onnzzlnr cylinder engine, seems to pre—


@l
l


SECTION AND PLAN or MAUDSLAY’S annum};
manure mrcnzn.
Fig. 2071.
sent the largest power possible in a vessel of given
draught, without machinery above deck, and that in
the least possible space. Each cylinder, Fig. 2071,
consists of 2 concentric ones, and the piston fills only
the space between them, which, however, is at least
:Z—ths of the whole area. From this annular piston two
rods support the T or Y pieces precisely as in the
last described variety, which this resembles in all the
remainder of its disposition, except that the valve-box
is attached to the after side of the cylinder. The
progress from that form indeed to this, is obvious and
unavoidable. The passages at m, Fig. 2070, formed the
two cylinders virtually into one chamber, nearly sur-
rounding the space in which the crank-rod descended,
which space now becomes the inner cylinder; and as
the annular piston here has a less extent of outline than
two circular pistons equalling it in area, a saving of
friction arises from the change, as well as a more im-
portant one of stowage-room.
Much trouble has been wasted in attempts to carry
the paddle-boards through the water more perpendicu-
larly, or quite perpendicular to the course of the
vessel, for which purpose they have even been mounted
on endless chains passing round two drums, like the
present paddle-wheels, on each side. But with the
single wheel it is easy, by making each board turn
on two pivots in its ends, to keep them all, by a
little appendage on the parallel-ruler principle, vertical
throughout their revolution, which at first sight seems,
besides the above advantage, to make them enter and
leave the water edgewise and without splash, and the
considerable loss of power absorbed therein. This,
although it once led to the extensive trial of such
,featlzerz'ng paddles, is entirely erroneous, arising from
the wheel being regarded as if its centre were at rest,
or as if, the vessel being at anchor, the object was
only to excite a current in the water. But when we
combine the forward motion of the vessel with the
rotation of the wheel, we find that the boards, if
fixed to it radially, will each take successively some
what the positions shown in Fig. 2072 at 29112212.
There is a certain circle an, smaller than the wheel's
periphery, so moving that its speed of rotation just
equals the vessel’s rate of advance, so that in this
circle (as in the tire of a carriage wheel) the lowest
point is stationary, and the highest advances twice
as fast as the axle. Consequently, any point in this
circle, or at this particular distance from the axle,
describes the same series of curves cccc (called
cyeloz'cls) that a point in the edge of a rolling wheel
does, and hence this is called the rolling circle. It
evidently cannot be a fixed circle in any wheel, but
varies in size according to the performance of the
vessel, or the proportion of the efiect obtained to the
power spent. A wheel may be turned so slowly as
not to propel the vessel at all, and then the rolling
circle will have no diameter. When largest, it evi-
dently can never equal the diameter of that passing
through the centres of pressure of the boards, for
then the whole power would be spent in propelling
the vessel, and none in driving back water, which is
impossible. The parts further from the axle than
an must not only cease advancing when at the

bottom of their course, but return or retrograde, and
736
STEAM-NAVIGATIO N.
describe a loop, as seen in the dotted curve 1010 p10,
enters and leaves the water almost cdgewise, at least
described by the outer edge of a board; and it will be far more so than it would do if kept always vertical.
seen that the board, during its immersion, moves very
like the blade of an oar most skilfully feathered, and

But the positions the boards should keep, if we
would have them feather quite accurately, would be as



Fly. 2072.
m Fig. 2073, all diverging from a point e at the top
of a circle, whose size depends on that of the rolling
circle. The better the performance of the vessel, the
lower will this point 0 become.


”_%'__ To produce
/>< \>‘*’\ something like
74" ' “ks: this movement
/ of the boards,
17,’ (though neces-
sarily always
alike in the same
wheel,) is the
object of the
modern feather-
ing wheels,
which are all
similar in prin-
ciple, and will
be understood from Fig. 2074. The principle was
first introduced in Morgan’s wheel, from which the
others only differ in details of the connexions.
at
Fig. 2073.






__ <2 ' N“
“a

PRINCIPLE 01? MORGAN’S AND OTHER FEATHERING
PADDLES.
Fig. 2074.
The white arms are those of the wheel, formed into
one rigid frame by two concentric circles or polygons,
of which, to avoid confusion, the outer one is here
omitted. The boards turn on axes at the corners of

this outer polygon, and have each an arm projecting
from the back at an angle of about 7 0°, and to the ends
of ‘these are jointed the black radii seen meeting at
a centre a little in advance of, and higher than that
of the wheel. This centre must be fixed to the
paddle-box, and allow the several black arms to turn
on it independently of each other, so that the angles
between them may vary, and the modes of doing this,
and still preserving the connexion and rigidity of the
wheels, lead to the several varieties of feathering
paddles; but it is extremely doubtful whether their
saving of power compensates for the complication and
presence of joints in a part so much exposed to vio-
lence, and especially for the weakness arising from
the impossibility of giving the axle a bearing in the
outside of the paddle-box. The difi‘erence of effect be
tween rigid and feathering paddles is found to be very
small when both are no more immersed than is now
usual, although it increases very rapidly when the
immersion approaches that represented in Fig. 207 4..
The name ey/eloz'dal paddle has also been rather
absurdly given to a variety of rigid paddle, in which
each board is divided longitudinally into three or
more strips placed as in Fig. 2075, in order that, as
/ /\:\’,:-‘-l-_l ‘\ s\\
//j/,/l ~"':l:: \\ \
/>/>:>/ / / //
/ / \\\ \
/ ‘I //
l
;l
lll
\ \
\ \\ '-
\\ /A/\;// ,....
N
/

\ \/\ //
\\\7\\:r:j/\;\§//
\7‘~Tl -/ //
\\____l //
Fly. 2075.
they enter the water, it may be less splashed than
by one unbroken surface. The three enter it at once,
but at difi'erent places, and they emerge from it suc-
cessively, but at nearly the same spot. There is no
STEAM'NAVIGATICN.
737
particular advantage in placing them with reference
to a cycloidal curve, nor can the name be accounted
for, unless as an advertisement.
From the earliest dawn of speculations on mechani-
cal propulsion, the screw propeller, nearly in the
forms now used, had been regarded among the most
likely to succeed in water, and Bernouilli, in the
middle of the last century, theorised upon this, as
upon nearly every conceivable form of propeller, in the
prize essay above-mentioned. Paddle-wheels, how-
ever, so took possession of the field of practice that
nothing else was seriously tried, until, in the year
1836, Mr. J. P. Smith imagined a new and probably
the best place for such a screw, viz. in a square
aperture to be left open through the “ deadwood,” or
thin solid prolongation always made from under the
stern down to the keel, chiefly in order, apparently,
to fill out a resisting plane back to the rudder, which,
with open space before it, would not act. [See Snm]
A company being formed to carry out this patented
idea, Sir John and Mr. George Rennie alone, among
English engineers, had the science to recommend and
put it in practice.
The nature of this propeller is precisely that of a
windmill or smoke-jack, only inverted in action, the
machine acting against the fluid instead of the fluid
driving the machine. At first, two extreme and
opposite treatments of it were used, Captain Ericcson
having patented one of almost as broad and shallow
a proportion as the turning ventilators, and having
6 vanes at its circumference, three ‘of which con-
tinued to the axis (the others being stopped by a ring
about halfway between the centre and circumfe-
rence); while Rennie adopted a single vane winding
round the axis like the thread of a screw, perform-
ing one complete turn. At present a medium
between these, viz. a screw of two threads, each
making baif a turn, has become general, but the
varieties of curvature that have been tried are almost
endless. The
general en—
closing con-
tour has been
made not cy-
lindrical but
conical, and
that in both
direction s,
but common-
ly with the
larger end
b a ck w a r d.
The pita/z, or
rate of the thread’s advance along the axle for each
degree or other angular measure of its rotation, has
been variously adjusted, and in Mr. Woodcroft’s very
successful screw, is made to increase gradually from
one end to the other, so that a particle of water after
undergoing the action of the part it first meets,
may yet receive further impulse from another part.
The whole of this increase only amounts to about
a twentieth quicker pitch at one end than the other.
VOL. II.


Fig. 2076.

Lastly, flab surfaces have leen substituted for the
threads by Captain Carpenter, who uses two propellers
under the ship’s quarters, and leaves the deadwood
unperforated. A propeller with flat vanes resembles
a sort of paper windmill, common as a toy in some
places. It has the great advantage of enabling the
vanes to be each so turned round as to come into
one plane, offering no resistance to the sailing of
the vessel when steam is not used. Mr. Maudslay
has patented an apparatus for doing this with vanes
not flat, but whose curvature is so managed, that,
when thus turn—
ed, they are in-
cluded in. the '/
thickness of the
keel, and thus
offer as little‘
resistance as pos-
sible. Fig. 207 7
shows the plan \ w"
with the vanes §\\\\\s in their working position; Fig.
2078 their plan
when folded out
of use ; and Fig.
2079 their side
elevation, r 9'
being their full
width, to which
the aperture is.
adjusted, and at
the width they
occupy when in
action. A sys-
tem of short le-
vers moved by
the rod 13, fixes
and holds them
in either posi-
tion, and when
released by this,
they are succes-
sively brought to
the top of their
circuit, and there
turned into the
required position by a tiller 0. Previous to the
contrivance of this feat/wring screw, the clumsy expe-
dient of unshipping the whole mass was performed,
or proposed to be performed, in sailing vessels, with
auxiliary steam ; and it has even been proposed by
theorists to carry screws of different powers and
qualities, and ship or unship them according to the
hourly variations of weather!
- The difficulty that was found in the early trials of
the screw, and perhaps still exists, only evaded a
little, is the obtaining a sufficient velocity of rotation,
with large engines and machinery of constant contact.
The velocity best adapted to the paddles is such as to
make the relation very happy between the circum-
l'erence of paddle-wheels and the number of strokes
3B


“\r
Fig. 2079. MAUDSLAY’S PEATITERING
scnnw.
738
STEAM-NAVIGATION—~STEAM HAMMER.
per minute easily attained by steam pistons of every
size; or perhaps we should rather say, the number
of strokes habitually used in land engines, and to
which therefore their settled proportions and forms
had been designed. It was forgotten that these pro-
portions and forms were not laws of nature. The
excessive subdivision, or rather iliseoizizezvioiz of sub-
jeets in the minds of a people accustomed to extreme
division of labour, such as the Chinese or the English,
leads at length to the regarding of purely artificial
and arbitrary things, if a little out of our own pecu-
liar province, as natural data.
breadth of a brick, or the proportion between the
cylinder and steam-pipe of an engine, have been re-
garded by architects in each matter, much as we
might regard the dimensions of the head and neck of
a horse. It thus comes to be forgotten that the pro-
duction of a good whole requires anything more than
perfect producers of each detail, and perfect fitters to
put them all together. There are English men who really
suppose that between good aletail-ma/aers and good
putters together, a thing may be made; for the grand
evil thus induced in every matter, and in most human
afi‘airs is, in three words, wemt of architects, want of
Vitruvius-like regarders, (theorists,——to “theorize ”
is to regard or look at,) regarders of all the various
subjects embraced in, or bearing upon, one work;
for it is now the fashion carefully to portion out details
and to collect together such only as are, or appear to ,
be, related: each set of details has its own world of
fancies and of connoisseurs, and it is rare to find two
sets mentioned on the same sheet.
The reader will not be surprised, then, that as it is
found that a canal horse can do most work when
drawing at the rate of 220 feet per minute, it was
concluded that all prime movers, and consequently
all steam pistons should move at that rate; which
law of nature has been so well known to those
truly practical men, English engineers, as to have in-
fluenced all their practice for half a century, and pre-
vented probably many more important things than
screw steaming. This natural speed determined the
natural proportion between the various parts of an
engine of course, and hence the non-applicability of
engines to turn a screw, which not being the work
for which they were made, evidently could not be the
natural propeller for steamers. The fact however is,
that until we find a natural pressure for steam, there
is no speed of piston more natural than another; and
until we find a natural limit to the pressure at which
steam can be used, there is no limit to the speed
(and consequently the power) attainable in any given
cylinder, except the velocity with which the air-pump
valves fall into their places by gravity; and there is
no conceivable reason why these should be moved by
gravity, and not, like the other valves, by the engine
gear.
Without such changes, however, the absurdity of .
employing four engines to turn one axle has been
obviated by applying Bishopp’s disc engine, (see
STEAM-ENGINE, and the steel engraving,) although
the unequal wear is a great objection to this and all
The length and '

rotary engines. It seems better to use two common
cylinders with such large ports and steam passages as
to allow of the requisite numbers of strokes, and a
diameter probably exceeding their length. Messrs.
Maudslay and Field’s method is to place these hori-
zontally, and both on the same side of the axle.
Wherever they act on different cranks, the arrange-
ment must evidently be unsymmetrical or one-sided,
and hence Messrs. Mather, Dixon & Grantham have
a very neat way of turning one single crank by two
rods descending from cylinders above it, each inclined
415°, so that they are at right angles to each other;
and they increase the compactness by making these
oscillating engines with their stuffing-boxes down~
wards, neither of which peculiarities is necessary.
The turning of one crank by two pistons, each in-
clined 415°, was first practised in the great engine
erected to drain the Thames Tunnel.
The screw shaft has also been driven by different
kinds of flexible bands passing round it and a large
revolving drum above, which is turned by the
engines only once for every 3 or even 4! revolutions
of the screw; but the rapid, wearing out of the
flexible band seems to have precluded this kind of
multiplying wheel, as the jolting of cogs has done
every other kind. Otherwise, Watt’s sun-and-planct
wheel affords an extremely simple contrivance for
changing the reciprocating into a rotary motion
making any number of turns, more or fewer than its
own strokes.
STEAM HAMMER. One effect of that excessive
division, not only of labour, but also of thought and
attention, which, while it so multiplies machinery,
tends to reduce the machine-users or even makers
themselves to machines, is well exemplified in the
still nearly universal instrument for making wrought
iron, by subjecting the crude lumps of it, in a soft
state, to the blows of a heavy hammer. Probably this
Helve-liammer, as it is called, (see Inorv, Sec. vi.) was,
when contrived, the very best expedient then practi-
cable for its purpose. Most contrivances of those
times were so. It was preeminently a practical age,
that age which could produce inventions without
patents, and afford to bring to perfection such costly
and diflicu'lt things as the wimlmill, which mathema-
ticians, in trying to amend, found they could not
imitate (including the gevemor, which Watt could
not improve, but only translate into iron); the skip
and the sail, whose mysterious perfections our science
can neither improve nor explain; the ever weather-
proof and unsinking rozfi, the fire-proof and beautiful
church and galleries, or the no less lovely and perfectly
acoustic eliapter-lzall and preaching beptistery; and so
many unimprovable contrivances, and not one for false
or artificial wants. We must not imagine, while
enjoying all these things, that because such inven-
tions were not made for the purpose of enriching one
person at the expense of all others, and were not
continually superseding one another, the times were
less inventive or less “practical” than ours. The
helve-hammer will tell us quite a difi'erent story.
Doubtless, then, it was the best means practicable,
STEAM HAMMER.
739
to that practical age, of lifting and letting fall a
heavy mass by a watenwheel. It would not be so
now, for several reasons. We have ways open by
the pressure-engine, &c., of storing and applying the
whole water-power to lift it directly, and only as
often as wanted, instead of a chance remnant of that
power diverted to give first a rotary motion, and from
this diverting at further loss a clumsy invariable ham-
mering. But what has thus been barbarous, ever
since the recognition of distinct laws of motion by
Galileo, becomes in the highest degree absurd, now
that steam-power takes the place of water. For the
very first step—the action of the steam on the piston
-—gives the exact motion required, incomparably
better than the final result on the hammer does.
The piston is lifted and falls vertically, and with its
whole weight (friction only deducted), because guided
in a way that the hammer might just as easily have
been. But because such guiding was impracticable
in the age when the helve was invented, it must be
lifted and fall in a circular arc, and with only about
a thircl of its total weight. Moreover, the circular
motion prevents its face and that of the anvil from
being ever parallel when anything is between them,
and they must be more inclined the thicker the object,
and cannot be separated beyond a certain very limited
distance ; on approaching which thickness, an object
so diminishes the fall of the hammer as to receive
a very diminished effect from its blow. Yet a whole
train of machinery must be interposed to change the
motion of the per/‘Fact hammer, the piston, first into
a rotary motion, and then again with blows and great
loss into the motion of this most clumsy and inflerior
hammer; simply because the different links of the
chain happen to be different men’s trades, and we no
longer regard trades as made for their work, but the
work for them.
An engine-shaft being projected a few inches thicker
than had previously been made, no hammer in England
was capable of forging it; and the projectors having
informed Mr. James Nasmyth of this, his attention
was drawn to this specimen, perhaps an exceptional
one in machinery, of the kind of practical wisdom that,
in every other branch of our arts, he would probably
have found the rule instead of the exception. The
result was the speedy production of one of the most
perfect of artificial machines, and noblest triumphs of
mind over matter, that modern English engineers, we
believe, have yet developed.
In the elevation on the steel plate annexed, a is
the hammer, and h the anvil ; the former fixed in the
hammer-{Bloch IE‘ r, a mass weighing from 30 to 60
hundredweight, and the anvil similarly fixed in the
anvil-hloc/c e e, large enough to resist by its inertia
the whole blow from the falling mass, and so lose
none of its impact, even should the ground below be
yielding. The two uprights or standards as form the
guides to the ascpnt and descent of n F, but leave
convenient space round the anvil, which is greatly
deficient in all tilt-hammers. On the standards is fixed
the entehlatnre or lintel c, which also forms the base
of the steam-cylinder n, and the passages into it, as

seen sectionally at f g in the separate figure. Before
these is fixed the valve-hoax J, enclosing the slicle or
valve e (small figure), whose rod or spinclle ll ascends
through a stuffing-box, and ends in a head or small
piston m working in a small cylinder M, called the
steam-spring. A small pipe n runs from the valve-
chest up to this small cylinder M, and the consequence
is, that whenever steam is admitted to J, it also has
access to M, and keeps the slide e down in its lowest
position till some greater force lift it against this
steam-spring. When the steam from H is admitted to
J by opening the throttle or shut-of valve in the box
I (which is done by the rod cl, and lever-handle
also marked 03, within reach of the attendant at z), the
slide-valve e is kept down so as to admit steam freely
under the piston L and at once lift it, with the rod E
and the suspended hammer. The bottom of n is
enlarged, and buried in a cavity of the block :rr,
with several layers of hard wood, both below and
above it, which are found elastic enough to prevent
injiuy from the shocks, and the attachment is com-
pleted by keys h driven above this wood. The piston
and hammer then are lifted until the position of the
slide e shall be altered, which may be done by the
attendant pressing down a lever e, which, by the long
sliding rod s r r o, draws down the valve lever in and
lifts l against the steam-cushion in M. This, by
cutting off the inlet passage f from the boiler, and
opening it to g, which leads to the waste-pipe x and
thence to the open air, will leave the piston unsup-
ported, and allow the hammer to fall. But should
this not be done, either by the above hand-gear or
the machine itself, in the manner about to be de-
scribed, the piston cannot be driven against the top
of the cylinder, because it must first pass the holes
h h, which, as soon as it is above them, will let out the
surplus steam into a passage i leading to the waste-
pipe K. At the same time these holes serve two other
purposes, for as soon as the piston rises high enough
to close them, the air above is shut in, and forms a
cushion not only to protect the top of the cylinder
from a blow, but, by its perfect elasticity, to send the
piston down again with an addition to its weight, so
that no momentum is lost, but all goes towards the
impact on the anvil.
Let us now examine the self-acting gear which is
to perform this change at any required point in the
ascent of the hammer, thus letting it fall from any
proposed height. The rod 1?]? is capable, besides its
up and down motion, of turning on its axis, by the
attendant turning the winch of the short horizontal
axle T ending in a bevel wheel Q, which turns a simi-
lar one seen on the said rod P, which it carries
round by a projecting feather, while allowing it to
slide ‘freely up or down. Above this, a length of r,
nearly equal to the range of the hammer, or of the
piston, is seen to be screw-cut. Parallel to this, and
a little nearer the hammer, is the perfectly similar
screwed axle U, (partly hidden,) which however can
only revolve, and not rise or fall. The two screws
are seen to be right and left-handed, but in other
respects just alike, and are coupled so as to turn
fi
3 n 2
740
STEAM HAMMER—STEATITE.
constantly together (contrary ways) by the two equal
spur-wheels r r, one fixed on the top of U, the other
on 1?, managed, like the bevel-wheel below, to‘turn
with the axle, but not to rise‘ or fall with it.~ On; each
screw is a nut; and- these being prevented‘ turning by
the piece 0 connecting them, it is evident that “when
both screws‘ are turned, by turning the winch at T; the‘,
two nuts will travel up or down exactly together”
because th'elscrews are equal. Now the piece 0', 'con-
necting them, is part of a bent lever o 0, whose ful-
crum or pivot-is attached. to the nut of U, the partly‘
hidden screw; and-v, which hides it, is one"- of two_-'~
guides to ‘preserve the ‘vertical motion of this .nut.’
‘The end of; all thisis to carry the whole lever o o, by-
its fulcrum} bodily up ‘or down, and,- without change.
in its own. posture, leave it at any'required height.‘
Its end 0 is a friction-pulley, and‘ as .the hammer-block
rises, a tappet N fixed ,thereon m-ustl- catch 0, lift it,
and keep it up ‘much higher for thelrest of the ascent.
This cannot alter the place of the. fulcrum-nut on U,
and therefore depresses the other end- of the lever,
and \with it the nut of P, to which it is, jointed, and
the whole of r bodily, drawing .down o, and 1t, and
lifting l and the slide valve, so as to shut off the access
of steam, to let out that under the piston, and to drop
it and the hammer, shortly after it has thus lifted 0,
whose height therefore regulates that of the fall. But
this would not sufiice to make the hammer self-acting,
for in descending, it would again-leave 0, which would
follow it down into therformer position, raise 1? andQ,
and again admit _ steam ‘as’ at ‘first, whichafter. a oer-1
tain amount of compression would stop the descent.v
If the hammer reached to strike a blow, it would not‘
be with its full weight, ‘and it‘ might not strike at all,
but only oscillate through a certain distanceabove. and
below 0 ;‘its passing .0, whether in rising or' falhng,
being the cause of its stoppage and reversal soon
after. A means of keeping 2 Q it down, then, when
once depressed, is necessary for giving a full blow.
This is furnished in the trigger, a small bent lever
p w. The weight of its handle y, or a spring depress-
ing that handle, keeps its point (a; pressed against Y,
which is hereabouts enlarged; and when the enlarged
part gets below ev,-'this catches onits shoulder, and
keeps 1> down, and would do so indefinitely, until the at-
tendant released it by ‘lifting y. Thus afull blow is in-
sured,_but the rise of the hammer after it has .struck,
and preparatory to another blow, is made to depend
on the attendant. To make the machine perform
this, is the last and most ingenious part of its action.
Observe, that it has to release the trigger ie, not at the
moment of coming down to any fixed point, (that
would be easy,) but at .the moment of striking what-
ever is placed on the anvil, however shallow or deep
that maybe. To .make the release dependent on the
fact of ‘the tloze, at whatever height that may take
place, Mr. Nasmyth places, on the front of the ham-
mer-block, a lever .11, called from its shape the late/t.
Its longer end would preponderate considerably, were
it not supported by a spring behind the plate seen
covering that end. Now .the efi'ect of the sudden shock
of the blow is, to make this preponderate for a moment ‘
slift the hammer thus.

in spite of the spring. For, although the hammer and
the block are arrested, the chief mass of the latch x
is not so; but it persists in its downward course by
inertia, which, added to its weight, overcomes the
spring, (its weight alone not being sufficient for the
'purpose,) and compresses that spring a moment, until
.‘its elasticity drives it back. This little movement,
although momentary, is made to re-admit steam to
A long upright bar s s (partly
‘hidden by d) is connected at each end to v, by short
and equal-links, the lower of which is seen at t, so
lthatvland s s; resemble the two bars of a parallel
ruler, the former fixed, and the latter capable of ap-
proachingto or receding from it, always parallel, and
usually kept thrust forward by its lower end being
bent to'» form-the-"horizontal arm v, touching and kept
forward by ‘the trigger ~20. But at the moment of the
blow, the above described kick of the latch x is given
against whatever part of the bar s s it may be opposite‘
to, 3 and momentarily pushing back that whole bar,
and-therefore v and iv, releases P, which immediately
ascends'or. allows the valve-rod l to- be pressed down
by its steam-spring, and the steam readmitted to raise
the piston and hammer. We know no other instance
of an action in machinery being effected by the iizertia
of a body, the only force really applicable in this case.
It only remains to say, that the shock with which
N strikes 0 is prevented from jarring the valve-gear,
byr beingiconnected with Q at p, in the same manner
as the piston-rod E with the hammer—block, wood
being interposed rand when-.the rods Q, r are elevated
?to=t-he'..position showman enlargement at-the bottom
elnterslafhollow fixed cylinder s, .called the differ, and
is received by layers of leather.
The control over the hammer given by the handle
y of the trigger, without ;readjusting the height of
fall, is very perfect and useful; as, by keeping ;/ up,
the blows become all stopped by fresh steam intercept-
ing each, so as either not to strike, or strike most
gently; and on letting p drop, 'afull blow is given.
A small nail, it is said, may be driven and neatly
finished with repeated taps, or ._a nut; cracked without
injury to the kernel, by this mass,~whose free descent
will dash a 3-inch plank into. splinters. No other
machine, certainly not the smallest hand-hammer, is
so brought under the thorough control, rather of the
will than 10f the hands, or made so much like a part
of the manager’s self (obeying him like the pencil
of the artist or the keys of the musician), as this
Cyclops arm; which might squeeze into shape the
largest celestial bolt in Europe, and has almost mas-
-ticated ..-rolls exceeding the heaviest lumps of the
iron of space that our planet is known to have en
countered. ’ ,
STEARIG ACID—STEARINE. See CANDLE-q
OILS AND FATS—SOAP.
STEATITE, a soft magnesian mineral (silicate of
magnesia—see MAGNESIUM), unctuous to the touch,
for which reason it is also termed soapstone, It is
‘also known in Commerce as French efial/e. Its sp.. gr.
is 265 to 2'8; its colour is usually greyish-green, but
when worked and varnished, it becomes olive
.
I
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’c\\‘
STEATITE—STONE.
an
green. It occurs in beds generally associated with
talcose slate. Like potstoae and sevpeatz'ae, which it
nearly resembles in composition, it becomes con-
siderably harder by exposure to the air. When first
raised it may be easily turned with chisels: the turned
articles may be polished, first with sand and water, and
afterwards with tripoli and water, and, for the highest
gloss, with rotten stone and oil, woollen cloths being
used in each case. When the steatite has become
hard, the methods employed for alabaster, as described
under GYPSUM, may be resorted to. Steatite has also
been named figure stone, in consequence of its having
been used as the material for idols and other figures,
which form the household gods of the Chinese: it
was formerly supposed that they were made of a pre—
paration of rice. The refractory nature of soapstone,
and the facility with which it is worked, admit of its
being cut into slabs for fire stones in furnaces and
stoves, and for jambs for fire-places. It is also mixed
with blacklead in the manufacture of crucibles. It
is bored out for conveying water instead of lead
pipes. It is an excellent material for kitchen-sinks,
wash-tubs, bath-tubs, urinals, &c. It is readily
wrought, and may be bored, turned, and planed by
the ordinary tools of the carpenter, and it may be
screwed together almost as easily as hard wood. It
is used in the manufacture of porcelain: it makes the
biscuit semi-transparent, but brittle. It forms a
polishing material for serpentine, alabaster, and glass,
and removes grease spots from cloth. It is ground
into a powder and used for diminishing the friction
of machinery. Dana states that soapstone is used in
the United States for the sizing-rollers in cotton
factories; in which case they are of large dimensions,
such as Ali-,1; feet long, and 5 to 6 inches in diameter.
The advantages of soapstone as a material for baths
and sizing-rollers, are, that it is not affected by the
acid usually employed in sizing, and is not liable
to warp, contract, or expand, by changes of tem-
perature and moisture.
STEEL. See IRON, Sec. vii.
STEEL ENGRAVING. See Enenavrne.
STEELYARD. See Barancn, Fig. 89.--SrA'rIcs
AND DYNAMICS.
STENCILLING. See PAPER—HANGINGS.
STEREOTYPE. See PRINTING, Sec. vi.
STILL. See DISTILLATION.
STOCKING. See Wnavrnc.
STONE. The art of gaarrgz'ag or getting out
stone from the earth, is one of great antiquity, coeval
indeed with the art of erecting buildings of hewn
stone. The excavation in the ground from which
stone is extracted, is termed a quarry, from the cir-
cumstance that the stones are quadrated (qaarre') or
formed into rectangular blocks. Until the invention
of gunpowder, the wedge and the hammer were the
only tools used in working a quarry, but the intro-
duction of that powerful mechanical agent greatly
facilitated the operations of the quarry-man, and
enabled him to get out enormous masses with com-
parative ease.
The implements used in quarrying are almost

identical with those described under MINING, Sec. iii.
and represented in Figs. 11641, 1165, and they consist
of a borer or jumping z‘ooZ; a hammer for striking it ;
a scr'egaer for clearing the hole of the chips or pounded
materials; a clagz'ag bar for driving in dry clay if the
hole be too damp for the immediate introduction of
the gunpowder; a long thin copper rod called a
needle, which is driven into the charge while the hole
is being tamped, or filled up, with the assistance of the
tamping ear, with broken brick, pounded stone, 850.,
so that when the needle is withdrawn a channel is
left for the insertion of the fuse.
In the ordinary practice of loading and firing the
holes, the following steps are usually taken :--1. To
dry outithe bottom of the hole, if necessary, with
small wisps of hay. 2. To pour in the gunpowder
until it fills a certain number of feet or inches from
the bottom of the hole. In a vertical or nearly
vertical hole the powder will drop to the bottom; but
if the hole be inclined, the powder should be scraped
down with a wooden ramrod, although an iron scraper
is often used. If the hole be horizontal, the powder
is introduced by means of a scoop, and if it incline
upwards, a cartridge is employed. 3. The needle is
now introduced, with the point inserted well into the
charge, and the handle or eye projecting above the
hole at the top. 4.‘. A little wadding of hay, straw,
or turf, is put in over the powder. 5. Then comes the
tamping, which may consist of small quarrystone and
dust, unless it contain flinty particles, which strike
fire, in which case broken brick may be used. The
tamping is rammed down an inch or two at a time by
means of an iron rod or tamping bar, the needle being
frequently turned round to prevent its being fixed.
6. The last inch or two of the hole is filled up with
damp clay. 7. The needle being carefully pulled out,
the narrow opening left by it is filled with loose fine-
grained powder (or with straws filled with powder),
into the upper end of which is inserted a piece of
touch-paper sufficient to burn half a minute: this
being lighted fires the train and the charge: the
quarrymen being in the meantime sheltered from the
effects of the explosion. The touch-paper is made by
soaking coarse paper in a strong solution of saltpetre
or gunpowder, and then drying it.
The chief expense of quarrying is the boring of the
holes necessary for the insertion of the charge. Where
the rock is very hard, this is a slow and toilsome
operation; and any practicable contrivance for facili-
tating it or for abridging the time required for its
performance, would be a real improvement. In the
granite quarries at Dalkey, near Dublin, it is stated
that three men, two striking a 3-inch jumper, and
one man holding and turning it after each stroke,
were able to bore on an average 4t feet a day of holes,
varying from 9 to 15 feet in depth; or with a Qlz-inch
jumper, 5 feet per day; with a 2;}: inch jumper, 6 feet
per day; with a 52-inch jumper, 8 feet per day; with
leg-inch jumper, 12 feet per day; and with a 1-inch
jumper, for breaking the fragments of rock to smaller
pieces, one man bored 8 feet per day. In these
operations the waste of steel and iron was nearly as
741%
STONE.
follows:--a 3-inch jumper took for its bit 2 lbs. of
steel, with which it would bore 16 feet, requiring to
be dressed or sharpened 18 times: the waste of iron
was 18 inches to each steeling, or 1%.;-inch for each
foot bored. The 2-inch jumper took 1%- lb. of steel:
the li-inch jumper took ~2- lb. of steel: and the 1-inch
jumper 3 oz. of steel. These jumpers would bore
from 18 to 241 feet, with each steeling, and required to
be sharpened about once for every foot bored. The
weight of the hammers used with 3-inch jumpers
was 181bs.: with 215 and Qé-inch jumpers, 16 lbs:
with 2 and lg-inch, 14h lbs.: and with a 1—inch
jumper, used by one man, a hammer of 5 to 7 lbs.
was used.
Glam jumpers, so called from their mode of work-
ing, are from 7 to 8 feet long, with a steel bit at each
end; their general diameter is 1% to lé-inch. Two
men can bore about 16 feet per day with one of these
jumpers. This form of jumper is more efficient than
that which is struck on the head with a hammer. It
is sometimes used with a spring rod and line. It is
adapted to vertical or nearly vertical holes, and to
rocks of moderate hardness. With granite the
edge turns so rapidly, and the sharpenings require to
be so often repeated, that the jumper and hammer
are preferred. Drilling instead of boring the holes
would greatly abridge the operation; but the cut-
ting edges of the tools will not stand in any kind
of stone.
“ Upon' the judicious selection of the position of the
holes will, in a great measure, depend the useful effect
of the blast; but two leading errors are committed by
quarrymen or miners in general, viz. selecting an
injudicious position for the charge, by which the
action of the powder is exerted in the direction of the
opening where it was introduced; and the adopting
as a rule for the several charges, to fill a certain
number of feet or inches of the hole bored, usually
one-third of its depth, instead of employing given
weights adapted to the lines of least resistance. The
line of least resistance is that line by which the
explosion of the powder will find the least opposition
to its vent in the air. This need not necessarily be
the shortest line to the surface; as, for instance, a
long line in earth may, from the same charge, afford
less resistance than a shorter line in rock. Supposing
the matter in which the explosion is to take place to
be of uniform consistence in every direction, charges
of powder to produce similar proportionate results
ought to be as the cubes of the lines of least resist-
ance, and not according to any fanciful depth of hole
bored. Thus, if 4! oz. of powder would have a given
effect upon a solid piece of rock of 2 feet thick to the
surface, it ought to require 13% oz. to produce the
same effect upon a piece of similar rock 3 feet thick;
that is, as 8 (cube of 2 feet line of least resistance) is
to 4 (charge of powder in ounces), so is 27 (cube of
3 feet line of least resistance) to 18% (charge in
ounces) ; or what is the same thing, half the cube of
the line of least resistance expressed in feet will, on
this particular datum, be the charge in ounces, as
follows :--

Charge of Powdr r.
. OZ.
Line of Least Resistance
in feet.
lbs
1 . o 05
2 . 0 4
3 .. 0 13:}
4 .. 2 0
5 .. 3 1431,;
6 .. 6 l2
7 .. 10 11%
8 .. 16 0
These quantities being common, merchant’s blast-
ing powder will be found adequate for any rock of
ordinary tenacity; but a precise datum should be ascer~
tained by a few actual experiments on the particular
rock to be worked. Thus, with a 2-feet line of least
resistance, A to B, Fig. 2080, it should be ascertained


whether oz , 6 oz., or 8 oz. are requisite to produce a \-\\
\
\\
good effect ; with S-feet
at
line of resistance, whether \
13%- oz., or 18 OZ., 01' 27 OZ., '\ s:
\\
\
Fig. 2080.
adopted for guide in the \ \
service.” 1 If the charge
be judiciously disposed,
there will be only a trifling
report, and the mass of rock will be lifted, and
thoroughly fractured, rent, or thrown over, without
being forcibly projected; whereas, in the common
mode of blasting, a loud report is heard, louder in
proportion to the less useful effect produced, and
fragments of stone are scattered about to a consider-
able distance.
There is an economy, both in labour and powder,
by establishing on the rock an exposed front either
vertical or horizontal, for in such case a line of least
resistance can be obtained in a different direction from
that of the hole bored, as A B, Fig. 2080; for it must
be obvious that if the action of the powder be exerted
in the direction of the hole bored, a part of the ex-
plosion finds comparatively easy vent by that opening
in spite of the best tamping, and is wasted; whereas
if the explosion be forced through another direction,
the whole of its power is beneficially exerted.
In stratified rocks and close parallel beds and scams
it will be found much easier, and the effect more ad-
“his.
W1..-“ “WM \. \\ '\‘\\\\\\\\ \ \\'\\”“\\\'\\\\\\\\\§“\\&\§s\§
\=
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//%%
\\\ " '“
vantageous, to bore the holes in the direction of the
joints, and to place the powder as at A, Fig. 2081;

(1) Sir John Burgoyne, K.C.B , &c., “On the Blasting and
Quarrying of Stone for Building, and other purposes; ” Published
among the “ Professional Papers of the Corps of Royal Engi-
neers,” and also in a. separate form in Weale’s Rudimentary
Series.
STONE.
w?)
this will have more effect in lifting large masses than
if placed across the grain.
It is of importance to be able to ascertain readily
the space occupied by any given quantity of powder.
The following table, by Maj or-Gen. Sir Gharles Paslcy,
K.C.B., calculated for round holes of different sizes
from 1 to 6 inches, will be found useful :—
Diameter Ponder contained Powder contained Depth of‘ hole to
of'the m one inch 10 one foot contain 1 lb.
hole. of hole. of hole. of Poadcr.
Inches. lbs. oz. lbs. oz. Inches.
1 .... .. 0 W419 .... .. 0 5'028 .... .. 38 197
1% .... .. 0 0'942 0 11'304 .... .. 16'976
2 O 1'676 .... .. l 4'112 .... .. 9'549
25‘); .... .. 0 2'618 .. 1 1.5416 .... .. 6'112
3 .... .. O 377 .... .. 2 13'24 .... .. 4244
3,}; .... .. O 5'131 .... .. 3 13. 572 .... .. 3'118
4 .... .. 0 6 702 5 0'424 .... .. 2 387
4,1; .... .. 0 8 482 6 5 78-1. .... .. 1'886
5 .... .. 0 10'472 .... .. 7 13'664 .... .. 1'528
5% .... .. O 12 671 .... .. 9 8'052 .... .. 1263
6 .... .. 0 '15'08 .... .. ll 4 95 .... .. 1'061
The gunpowder used for the blasting of rock is
inferior in strength to that used for sporting or for
the army and navy; it is a cheaper and coarser
powder, and is preferred on the supposition that, by
igniting more slowly, the power is applied more
forcibly and etficiently than by the rapid shock of
powder of superior quality, such as must be used
for impelling projectiles. This appears to be a mis-
take, and there is little doubt that the sudden and
violent shock of superior powder would produce
more extensive cracks in the rock, which is the great
object to be attained, than the slower action of mer
chant’s blasting powder. Indeed, the success of gun- '
cotton, so far as it has been applied in quarrying,
seems to prove that a sudden violent action far more
rapid than that of the best gunpowder, performs the
largest amount of useful work upon the rock. It
appears, also, from some experiments by Sir J. Bur-
goyne, given in the work already quoted, that about
9 parts of Government powder are equal to 13 of the
merchant’s powder, and that it would be good policy
to employ stronger powder for blasting, even at in-
creased prices. The fine-grained powder made by
Government for the Rifle Service and by manufacturers
for shooting, would be too costly an article, but it is
considered that the best camzon powder might be
used with advantage. The cost of blasting powder
in the country is from 2!. 10s. to 3i. 10.9. per 100 lbs. 5
but powder similar to the Government cannon
powder might be sold at between 2!. 108. and 3!.
Good Government cannon powder contains 7 5 per
cent. of nitre, and 25 of sulphur and charcoal. [See
Gunrownnn] Merchant’s blasting powder contains
from 66 to '73 of nitre, and from 24 to 32% of sulphur
and charcoal, together with impurities.
The quarrymen are so impressed with the idea of
the advantage of the gradual ignition of the gun-
powder used in blasting, that it has even been recom-
mended to mix therewith a quantity of fine, dry
sawdust of elm or beech, in the proportion of g-d of
sawdust for small charges, and ~57 for large, and it is
asserted that this mixture will produce as good
results as equal quantities of gunpowder alone. The

action of the sawdust, by dividing the particles of
the charge, and causing them to ignite more gradu-
ally, is said to be the production of greater force on
the rock than by the‘ more sudden explosion, Those
who advocate this proceeding would, we should sup-
pose, contend that an ounce weight striking a body
16 times with a certain velocity would have the same,
or even a greater effect, than a weight of 1 pound
striking the body with the same velocity. The power
of the charge is also said to be improved by mixing
about I} of quicklime with the powder, on the principle
that it will absorb any moisture that may be in the
powder. If such really be the effect, the absorption
of water by tile lime would lead to the evolution of
heat, and cause the sulphur and the nitre to react on
each other, and lead to the formation of sulphate of
lime. Neither this practice nor the former would
be adopted by any one acquainted with the merest
elements of mechanical and chemical science. It is
also stated that if a hollow space he left above
the charge a greater effect will be produced than if
the tamping be continued down to the charge. For
example, in two similar holes the charge 0, Fig. 2082,
with a hollow space 8 over it, is said to produce as
W}; \
\ys \
\ \ III-l‘
. R





. \ “1
-....§\\&\\\\\\- g ‘ :2
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§\\\\\\I
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~- ‘5Q
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. \
i§\\\\\\\ \\ \\\\\s
Fig. 2*282.
good an efi‘ect with g or 3,-ds the quantity as the full
charge 0', provided the tamping 'r, from s to s, be as
good and as deep as that at T'. On this point Sir
John Burgoyne remarks, that “ an increased efl’ect
will certainly be produced by such hollow, in the same
manner as with guns, which are frequently burst by
the occurrence of a hollow between the powder and
the shot, but there must be great reason to doubt its
practical utility. No accounts are given of the well-
defined result of actual experiment, nor are any rules
attempted to be laid down for theext'ent of the hollow
spaces in proportion to the quantity of powder in the
charge, &c., to produce useful effect ; and yet these
must be matters of consequence‘; nor is it anywhere
stated that it has ever been practically continued to
be used, notwithstanding the great saving of powder
professed to arise from the adoption of this principle.
In large charges, the space that could be left would
be too small to produce any useful effect; and in
small charges, the more simple, quick, and cheap
way would be, by using the full charge of powder.”
With respect to the quantities of powder used at
a blast, the practice varies. In working quarries for
large stones large blasts are often used. Thus in the
Kingstown quarries, where granite stones for ashlar
74a
STONE.
work are squared to from 40 to 60 cubic feet each,
50, 60, and 70 lbs. of powder are frequently exploded
in a single blast, in some cases filling ggds ‘of a hole
of 4! or 3% inches diameter, and 20 feet deep. With
such a charge a mass of 1,200 cubic yards, or 2,1100
tons, has been brought down or thoroughly shaken
and rent. At Gibraltar, where the rock is a pecu-
liarly hard limestone marble, large masses are brought
down by the military miners under the Royal Engi-
neers, by boring holes about'9 feet deep, with flag-inch
jumpers, the charge being 4 ‘lbs. of powder: the
explosion has no apparent effect; nevertheless, the
rock is shaken below: the needle hole is cleared out,
and the hole again filled, the charge being from 8 to
121bs.; it is fired again, and the process is repeated
with a third charge of from 20 to '30 lbs. : a fourth
charge may even be fired, and in this way the rock is
greatly separated, and rent to the extent of 10, 20, or
30 feet in different directions. This plan is said to
waste less powder than the former, and to produce
a less violent projecting of stones.
Sir John Burgoyne recommends that greater pre-
cision be introduced into the practice of blasting,
which is usually conducted in a slovenly manner. He
would allot every charge by weight according to a
scale adapted to lines of least resistance or to the cir-
cumstances of the case. The overseer or powderman
should be provided with a strong copper canister con-
taining from 3 or albs. to 10.01‘ 1.2 lbs. of powder,
with a large mouth or opening, secured by a well-
fitting cover from spilling, accident, or weather, and
with a lock and key. Also .a set of marked copper
measures of the capacity of llb., éh oz., and 102.: a
copper cylindrical tube of '3 feet or 3% feet long by
%inch. diameter; a set of '3 tubes of about 1 inch in
diameter, each 3 feet long, with joints to admit of
being screwed into one length of 6 or 9 feet, or with
a larger numbeirof joints if deeper ‘holes ‘be employed‘,
so that when put together the interior may form one
smooth surface. 'There should also be a copper funnel,
with the bowl ‘large enough to contain aboutjl lb. of
powder, and the neck 2 inches long, and about g inch
diameter. By means of this funnel and the tubes,
the charge of powder may be lodged clear to'the bot-
tom of the hole, and if horizontal, or nearly so, by
pushing it ‘in through the 'tubeswith a wooden stick
or ramrod. With these precautions none of the grains
of powder hang about the sides of the hole, which is
a source of danger in the ordinary method. The charge
having been deposited, one end of a piece of patent
fuse is ‘inserted well into the powder, and the other
end is cut off about an inch beyond the outside of the
hole: a ‘little wadding is then pressed down over
the powder with the tamping-bar, and upon that
the tamping without any moist clay. The first blows
of the tamping-bar over the charge often lead to its
ignition: “to ‘prevent this, the ‘first 2 or 3 inches of
the tamping ‘should be merely pressed down gently
over the wadding, and the hard ramming commenced
.over that. It would be desirable if the tamping—bar
were tipped with brass. The tamping “being com-
pleted, the end of the fuse is lighted, and with these

precautions the explosion takes place with more cer-
tainty, and the whole operation is attended with less
danger than by the old method.
Bickford’s miners’ safietyfase is a great improve-
ment on the old method of laying the trains and firing
the charge. It is a cylinder of gunpowder or other
explosive compound enclosed within a hempen cord,
which is first twisted and afterwards overlaid with
another ‘cord for the purpose of strengthening the
casing thus formed: .it is next varnished in order to
preserve the contents from moisture, and it is lastly
covered with whitening to prevent the varnish from
adhering. This fuse can be used in damp situations,
and even under water. In wet quarries, or where
wet joints are met with in boring, and the holes fill
with water, the usual plan is to stop the leaky joints
in the hole by means of a paste of fine clay; but with
the safety-fuse the charge is put into a water-proof
bag, a length of fuse is closely tied in its mouth, and
the bag being pushed home to the bottom of the hole,
the tamping is completed, and the charge is fired with
as much ‘certainty and effect as in dry work. This
fuse burns at the rate of from 2 to 8 feet per minute.
Charges of powder are in some cases fired by means
of a voltaic battery, for which purpose a platinum
wire is ‘buried in the charge, and from each end of this
wire a copper wire proceeds to the battery. On
closing the circuit the platinum wire becomes red-hot,
and ignites the gunpowder.
A great variety of opinions have been expressed on
the subject of tamping‘; The object of this operation
is to obtain the greatest possible resistance over the
charge of powder, and if the tamping could be made
as strong as the rock itself it would be perfect. The
materials used in tamping are the chips and dust of
the quarry, unless it contain flint, such as would
strike fire with the tamping-bar. Fine and dry sand
is used in some places, or dried or baked clay, or
broken brick, or vegetable earth. It ‘has been found,
by experiment, that clay dried to a certain extent
forms, on the whole, the best tamping material.
Broken brick, tempered with a little moisture during
the operation, is the next best material. It has been
stated that, by pouring in fine dry sand, stirring it up
as it is poured in, in order.to make it more compact,
the slow and dangerous operation of driving in the
tamping maybe dispensed with. It appears, how-
ever, from a number of experiments, 'the results of
which are given by Sir John Burgoyne, “that sand
of any description, and however applied, is, when used
by itself, and for small blasts, perfectly worthless, and
quite inferior to clay tamping for larger explosions, at
least so far as for holes 9 feet deep by 2% inches in
diameter.”
Attempts have been made to increase the resistance
by fixing some ‘kind of plug or wedge in the loaded
hole. A conical piece of iron placed ‘immediately over
the charge, before -the tamping is filled in, was found
to give a great increase of resistance, as was also a
barrel—shaped plug driven in over‘the'tamping. 'Oap-
tain Norton concludes, from some recent experiments,
that a plug of deal placed over the powder, of ‘the.
STONE.
745
same dimensions as the bore, and about 3 or 41 inches
long, adds greatly to the force of the charge.1
In the operation of blasting the blocks are broken
irregularly, and the stone is wasted. Hence a more
economical method is often employed for getting out
the stone. Stone which occurs in contiguous strata
presents a number of contact surfaces, or planes of
cleavage, and the stone is more easily divisible in lines
parallel to these cleavage planes than in any other
direction : these lines form what is called the cleaning
grain of the stone. In order, therefore, to separate
a large block, a number of iron wedges are placed in
line a few inches apart on the natural face of the rock,
and in the direction of the cleaving-grain, and they
are driven into the stone with heavy sledges until a
part is loosened: a channel is then cut in the direc-
tion of the length of the intended block, and at a
distance from the natural edge of the stone equal to
its required breadth. The wedges are placed in the
channel, and driven until the stone is split in that
direction also. In very hard stones the wedges are
not placed in the channels, but in pool-holes sunk in
the direction in which the block is to be separated
from the mass. A similar operation is performed in
the direction of the breadth of the block, and in this
way a large portion is detached from the original
mass. The blocks are next reduced to a rectangular
form by means of a heoel, a tool pointed at one end
and flat at the other, with which the irregular parts
are chipped off. The blocks are then, by means of
movable cranes, raised upon trucks or low carriages,
and drawn on iron railways to the quays or wharfs
where the stone is shipped.
At the granite quarries of Rubieslaw, near Aber-
deen, which the Editor visited in the autumn of 1852,2
masses of rock are detached by boring and blasting
The bores are often as much as 12 to 16 and even 18
feet deep, and 2% inches diameter. The first firing
loosens a very large quantity of rock. The perpen-
dicular cracks or fissures caused by this operation are
filled with gunpowder and fired, by .which means the
mass is shifted several inches from its bed, and even
thrown some yards forward. This operation is called
balling. The rock is cut up into scantlings by wedges
as above described; but when the block is very deep
the cutting is performed by plug and feather. The
feathers are inverted wedges with circular hacks for
fitting the holes, the opposite sides being plain. The
holes bored are about 1% inch in diameter, 5 or 6 inches
deep, and in a row 6 inches apart. Two feathers are
put into each hole, and between the feathers long
wedges are introduced and driven until the block
opens in the required direction. [See Gunnrrn] A
large proportion of the work of this quarry consists
in working :up road metal for the streets of London.
There are various kinds of paving stones, such as
common sixes, so named, because as they lie in a pave-

(l) A-description of Captain Norton's Percussion Blasting Car—
tridge will be found in the Mechanic’s Magazine, No. 1553.
(2) The Editor takes this opportunity of offering his acknow-
ledgments to Mr. William Hay, the intelligent foreman of the
quarry.
ment their depth is only 6 inches: the superficial
extent of each stone is about 10 inches by 6. As
the stones increase in size they are called respectively
half-sovereigns, sovereigns, euhes, and impei'ials. The
freight to London is about 88. per ton, and the vessels
which convey the stones take in ballast at London,
and then, repairing to Sunderland, receive at that port
coals for Aberdeen; by which means coals are sold in
Aberdeen about 5 per cent. cheaper than if no granite
were transported by the same shipping, and conse-
quently the paving-stone is afforded cheaper in Lon-
don than if no coals were conveyed to Aberdeen. The
cost of paving-stone is about 138. per ton, which, with
the freight and incidental charges, raises the price in
London to about 2418. per ton. The stones are weighed
in the quarry by a very primitive kind of steelyard,
called a Duieh-haeh weighing machine. The following
engraving is from a sketch made in the quarry by our




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Fig. $2083.
DUTCH‘BACK 'WDIGHING MACHINE.
travelling companion, Mr. I-Iatcher. The length of
the short lever is 3 feet 8 inches, and of the long lever
11 feet. The stone weight is equal to 5 cwt. '
The various methods of working and dressing build-
ing stones are described under their respective titles
in this work. [See Mnsonnr—Gnanrrn—Sxnnsronn,
860.] We have, however, been lately informed of
some particulars respecting the sandstone of Edin-
burgh, which may be noticed in this place. The
sandstone of which the Scottish capital is built has
long been in evil repute for producing diseases in the
lungs of the masons who work it. The hardness of
the stone requires much chiselling, and causes it to
yield a fine irritating powder. Our informant3 says :—-
“ I have fallen in with the foreman of the masons who
built the Scott monument. He is an intelligent trust~
worthy person, and he gave me the following particu-
lars :-—The mortality among stone-hewers from affec-
tions of the lungs is notorious in the trade. It is very
rare to see ahewer who has reached the age of 50,
and not uncommon, on the other hand, to see men
who began to hew at 16 dead at 241. Many die about
35. Builders are as long-lived as their neighbours of
other callings. My informant knew several who had
reached the age of 70. The disease of the lungs,
which is so mortal, is called by the sufferers them-

(3) Dr. George Wilson, of Edinburgh. Most of our readers are
aware of the deservedly high scientific reputation of this gentle-
man; his friends only are aware of his unwearied activity in pro-
moting the happiness, and alleviating the sufferings of his fellow
creatures. We have been indebted to Dr. Wilson for information
and assistance in this 'work, which in several cases we have not
been permitted to acknowledge; nor would this note he allowed
to appear if our friend had to correct the proof-sheet of his con~
tribution.
7&6
STONE.
selves, emphatically, ‘ the mason’s trouble,’ which
means, simply, ‘ the mason’s disease ;’ the word lroulale
being constantly used in homely Scotch as equivalent
to disease. Masons in the country suffer less from it
than those in town, because the former build as well
as hew, whilst the latter either solely build or solely
hew. Carvers or sculptors suffer more than rough
hewers, and the hardest stones induce the disease
most quickly. In illustration of this my informant
referred to Craigleith stone, (a very pure sandstone,)
as so much harder than Binnie stone, (also a sand—
stone,) that a man who could chisel 15 linear feet of
the latter in a day, could only chisel 6 of the former.
Graigleith sandstone has always had an evil notoriety
as the most prejudicial to the hewers of the Edinburgh
building stones; and my informant, like all the masons
I have talked to on the matter, imputed its noxious-
ness to the large quantity of sulphur in it. Like most
sandstones, it does contain a very small proportion of
sulphuret of iron, but 1 need not say that it is the
fine siliceous powder that does the mischief. My in-
formant confirmed this by his statement, that when
a row of men were working together under a shed or
wooden hoarding, so great a cloud of sandstone—
powder was raised, that you could not, standing at one
end of the row, see the men at the other. Quarry-men,
he added, suffered less than masons hewing under
cover, because they worked in the open air.
“ The mason’s trouble, no doubt, includes several
diseases. It begins with efi'orts to clear the throat
and a short unfrequent cough. Difficulty of breathing
soon follows, much expectoration, frequently spitting
of blood, and in the end hopeless consumption. Some
linger for 18 months or more after being laid aside
from work. Most of them reach the grave much
more quickly: and medical men would no doubt give
different names to the affection of the lungs occasion-
ing death in different cases; but local irritation, end-
ing in organic disease of some portion of the breathing
apparatus, would be the history of nearly all. Seventy
men were under my informant at the Scott monument,
and during the 4! years which its building occupied,
18 men, according to him,‘ died of the mason’s trouble.
“ By the advice of Dr. Alison some of the men
were wire respirators, but they did not altogether
exclude the stone-dust; and he did not observe that
they did any good. He had heard that the German
stone-masons, who wear their beards, did not suffer
as his countrymen did; but he understood also that
they worked in the open air, and he thought that
that, probably as much as the moustaches, kept them
well. The Liverpool masons are now wearing their
moustaches, as are also the men in some of the Glas—
gow engine foundries.
“ So coolly do our masons contemplate their fate,
that when one of their number is compelled by the
mortal disorder to give up work, they speak of him as
having ‘gone to grass,’ and when he dies they rafile
his tools at one of the Freemason’s lodges for the
benefit of his widow. My informant seemed to think
it a matter of course that a mason must leave a
widow.”

Together with this information our kind corrc-.
spondent sent us a respirator recently invented by
the Rev. Mr. Nisbet of Canongate, Edinburgh. It
is sold for 28. by Messrs. Blackhall & Scott, Comb-
makers of Edinburgh. We have endeavoured to
represent it in Fig. 2084:. It consists of a piece of
horn adapted to the curvature of the mouth, per-
forated with a number of vertical slits, covered on the
outside with a single layer of black cloth, which serves
to filter the air, and prevent the particles of stone

RESPIRATOR F0 R. MASON'S.
Fig. 2084.
passing through. It is bordered on the concave or
inner side with a ridge of thick leather, which, with
an elastic band passing round the head, serves to re-
tain the little instrument close to the month. For
the protection of the nostrils, there is, projecting
from the top part, a flat piece of horn perforated
with holes, and also covered with cloth on the out-
side: on each side of this perforated horn, a flat piece
of horn is attached so as to enclose a large portion of
the nose. This respirator is used by millers and
colliers as well as by masons, but not largely by any.
A simpler respirator is made without a nose-piece.
We now return to the more immediate object of
this article. The choice of a stone for building pur-
poses is of very great importance, and, until recently,
had not been directed by scientific principles. Most
of our public buildings are hastening to decay in con—
sequence of the decomposition and disintegration of
the stones of which they are composed. The selection
of a stone which will resist the action of a smoky
atmosphere of varying degrees of moisture, of wind,
and dashing rain, of frost, and other meteoric causes,
becomes therefore a matter of high consideration.
And it was a wise proceeding on the part of Her
Majesty’s Commissioners of Woods and Forests, pre—
vious to the erection of the new Houses of Parliament,
to appoint a scientific commission1 to inquire into the
qualities of the various stones used in Great Britain
for building purposes, with a view to the selection of
a hard, tenacious, and compact material for the new
Palace at Westminster. We propose to give a brief
abstract of the Report made on the occasion.

(I) The Commissioners were Mr. Barry, Sir H'. T. de la Beche,
Dr. W. Smith, and Mr. C. H. Smith. The specimens of stones
collected were submitted to tests both mechanical and. chemical,
by Professors Daniell and Wheatstone, of King’s College,
London.
STONE.
74'7
The Commissioners did not consider it necessary to
extend their inquiries to granites, porphyries, and
other stones of similar character, on account of the
great expense of working them in decorated edifices,
and from a conviction that an equally durable, and in
other respects a more eligible material, could be ob-
tained for the object in view from among the lime-
stones or sandstones of the kingdom.
The Commissioners soon had striking proofs of the
necessity and importance of this inquiry in the la—
mentable effects of decomposition observable in the
greater part of the limestone employed at Oxford: in
the magnesian limestones of the minster, churches,
and other public edifices at York, and in the sand-
stdnes of which the churches and other public build—
ings at Derby and Newcastle are constructed; and
numerous other examples. The unequal state of pre-
servation of many buildings often produced by the
varied quality of the stone employed in them, although
it may have been taken from the same quarry, showed
the propriety of a minute examination of the quarries
themselves, in order to gain a proper knowledge of
the particular beds from whence the different varieties
have been obtained. An inspection of quarries was
also desirable for the purpose of ascertaining their
power of supply and other important matters; for it
frequently happens that the best stone in quarries is
often neglected, or only partially worked, in conse-
quence of the cost of laying bare and removing those
beds with which it may be associated; whence it
happens, that the inferior material is in such cases
supplied.
The stones used in building are named either from
the places where they are quarried, or from the chief
ingredients of their composition. The term freostoae
is applied indefinitely to that kind of stone which can
be wrought with the mallet and chisel, or cut with
the saw. It includes the two great divisions of lime-
s/oae and sandstone. The limestone of Portland has
long been used in the metropolis, but other kinds are
also employed.
Sandstones are generally composed of either quartz
or siliceous grains, cemented by siliceous, argillaceous,
calcareous, or other matter. Their decomposition
depends on the nature of the cementing substance,
the grains being comparatively indestructible. With
respect to limestones composed of carbonate of lime,
or the carbonates of lime and magnesia, either nearly
pure or mixed with variable proportions of foreign
matter, their decomposition also depends upon the
mode in which their component parts are aggregated;
those which are most crystalline being found to be the
most durable, while those which partake least of that
character suffer most from exposure to atmospheric
influences. The various limestones termed oolz'z‘es or
roestorzes, are composed of oviform bodies cemented
by calcareous matter of avaried character: they suffer
unequal decomposition unless such oviform bodies
and the cement be equally coherent and of the same
chemical composition. The limestones termed shelly,
from their being formed of broken or perfect fossil
shells, cemented by calcareous matter, suffer unequal

decomposition, in consequence of the shells, which are
mostly crystalline, offering the greatest amount of
resistance to the decomposing effects of the atmo-
sphere.
Sandstones, from the mode of their formation, are
frequently laminated, especially when mz'oaoeoas, the
plates of mica being generally deposited in planes
parallel to their beds. Hence if such stone be placed
in buildings with the planes of lamination in a
vertical position, it will decompose in flakes, according
to the thickness of the laminae; whereas if it be
placed so that the planes of lamination be horizontal,
or as in its natural bed, the amount of decomposition
will be comparatively immaterial. Limestones used
in building are not liable to the kind of lamination
observable in sandstones; but there are some varieties,
chiefly of shelly limestone, which have a coarse lami-
nated structure generally parallel to the planes of
their beds, and such stones should be placed in
buildings with the planes of lamination horizontal.
The chemical action of the atmosphere produces a
change in the entire matter of the limestones and in
the cementing substance of the sandstones, according
to the amount of surface exposed. The mechanical
action due to atmospheric causes, occasions either a
removal or a disruption of the exposed particles, the
former by means of powerful winds and driving rains,
and the latter by the congelation of water forced into
or absorbed by the external portions of the stone.
These effects are reciprocal, chemical action rendering
the stone liable to be more easily affected by mechani-
cal action, which latter, by constantly presenting new
surfaces, accelerates the disintegrating effects of the
former. Buildings in this climate are generally found
to suffer the greatest amount of decomposition on
their southern, south-western, and western fronts,
from the prevalence of winds and rains from those
quarters; so that stones of great durability should
be employed in fronts with such aspects. As an.
instance of the difference in degree of durability in
the same material subjected to the effects of the
atmosphere in town and country, the Commissioners
notice the several frustra of columns and other blocks
of stone that were quarried at the time of the erection
of St. Paul’s Cathedral in London, and which are
now lying in the Isle of Portland, near the quarries
from whence they were obtained. These blocks are
invariably found to be covered with lichens, and
although they have been exposed to all the vicissitudes
of a marine atmosphere for more than 150 years, they
still exhibit, beneath the lichens, their original forms,
even to the marks of the chisel employed upon them;
whilst the stone that was taken from the same quarries
and placed in the cathedral itself, is in those fronts
which are exposed to the south and south—west winds
found in some instances to be fast mouldering away.
Colour is of more importance in the selection of a
stone for a building to be situated in a populous and
smoky town, than for one to be placed in an open
country where all edifices usually become covered
with lichens; for although in such towns those fronts
which are not exposed to the prevailing winds and
‘741.8
STONE.
rains will soon become blackened, the remainder of
the building will constantly exhibit a tint depending
on the natural colour of the material employed.
Buildings which are highly decorated, such as the
churches of the Norman and Pointed styles of archi—
tecture, afford a more severe test of the durability of
any given stone, all other circumstances being equal,
than the more simple and less decorated buildings,
such as the castles of the 14th and 15th centuries,
inasmuch as the material employed in the former
class of buildings is worked into more disadvantageous
forms than the latter as regards exposure to the effects
of the weather. Buildings in a state of ruin, from
being deprived of their ordinary protection of roofing,
glazing of Windows, 820., constitute an equally severe
test of the durability of the stone employed in
them.
The durability of various building stones in parti-
cular localities, was estimated by examining the con-
dition of the neighbouring buildings constructed of
them. Among sandstone buildings were noticed the
remains of Ecelestone Abbey, of the thirteenth century,
near Barnard Castle, constructed of a stone closely
resembling that of the Stenton quarry, in the vicinity,
in which the mouldings and other decorations were in
excellent condition. The circular keep of Barnard
Castle, apparently also built of the same material, is
in fine preservation. Tintern Abbey is noticed as
a sandstone edifice, that has to a considerable extent
resisted decomposition. Some portions of Whitby
Abbey are fast yielding to the effects of the atmo-
sphere. The older portions of Itipon Cathedral;
Rievaulx Abbey; and the Norman keep of Richmond
Castle in Yorkshire, are all examples of sandstone
buildings in tolerably fair preservation. Of sandstone
edifices in an advanced state of decomposition are
enumerated Durham Cathedral, the churches at New-
castle-upon—Tyne, Carlisle Cathedral, Kirkstall Abbey,
and Eountain’s Abbey. The sandstone churches of
Derby are also extremely decomposed, and the church
of St. Peter at Shaftesbury is in such a state of decay
that some portions of the building are only prevented
from falling by means of iron ties.
The choir of Southwell Church of the 12th cen-
tury affords an instance of the durability of a
magnesio-calciferous sandstone after long exposure to
the influences of the atmosphere. The Norman
portions of this church are also constructed of mag-
nesian limestone similar to that of Bolsover Moor,
and which are throughout in a perfect state, the
mouldings and carved enrichments being as sharp as
when first executed. The following buildings also of
magnesian limestone are either in perfect preservation
or exhibit only slight traces of decay: the keep of Ken-
ingsburgh Castle; the church at Hemingborough of the
fifteenth century; Tickhill Church of the same date;
Hudderstone Hall of the sixteenth century; Roche
Abbey of the thirteenth century. The magnesian
limestone buildings which were found in a more ad-
vanced state of decay, were the churches at York,
and a large portion of the Minster, Howdon Church,
Doncaster Old Church, and buildings in other parts

of the country, many of which are so much dccom~
posed, that the mouldings, carvings, &c., are often
entirely effaced.
The Report speaks in high terms of the preserva-
tion of buildings constructed of oolitic and other
limestones: such are Byland Abbey of the twelfth
century; Sandysfoot Castle, near Weymouth, con-
structed of Portland oolite, in the time of Henry
VIII; Bow-and-Arrow Castle, and the neighbouring
ruins of a church of the fourteenth century in the
island of Portland. The oolite in the vicinity of
Bath does not seem to wear well.
‘ The excellent condition of the parts which remain
of Glastonbury Abbey, shows the value of a shelly
limestone similar to that of Doulting; whilst the
stone employed in Wells Cathedral, apparently of the
same kind, and not selected with equal care, is in
parts decomposed. In Salisbury Cathedral, built of
stone from Chilmark, there is evidence of the general
durability of a silicifcrous limestone; for, although
the west front has somewhat yielded to the effects of
the atmosphere, the excellent condition of the building
generally is most striking.
The materials employed in the public buildings of
Oxford afford a marked instance both of decomposi-
tion and durability; for whilst a shelly oolite, similar
to that of Taynton, which is employed in the exposed
parts of the more ancient parts of the Cathedral, in
Merton College Chapel, 850., is generally in a good
state of preservation, a calcareous stone from Hed-
dington, employed in nearly all the colleges, churches,
and other public buildings, is in such a deplorable
state of decay as, in some instances, to have caused
all traces of architectural decoration to disappear,
and the ashlar itself to be in many places deeply dis-
integrated.
In Spotforth Castle, two materials, a magnesian
limestone and a sandstone, have been employed, the
former in the decorated parts, and the latter for the
ashlar; and although both have been equally exposed,
the magnesian limestone has remained as perfect in
form as when first employed, while the sandstone has
suffered considerably from the effects of decomposi-
tion. In Chepstow Castle, a magnesian limestone is
in fine preservation, and a red sandstone rapidly de—
caying. A similar result was observed in Bristol
Cathedral, which afiorded a curious instance of the
effects of using different materials; for a yellow lime—
stone and a red sandstone have been indiscriminately
employed, both for the plain and the decorated parts
of the building; not only is the appearance unsightly,
but the architectural effect of the edifice is also much
impaired by the unequal decomposition of the two
materials.
Preference is given in the Report to the limestones
on account of their more general uniformity of tint,
their comparatively homogeneous structure, and the
facility and economy of their conversion to building
purposes; and of this class preference is given to
those which are most crystalline. Professor Daniell’s
opinion was that the nearer the magnesian limestones
approach to equivalent proportions of carbonate of
STONE.
lime and carbonate of magnesia, the more crystalline
and better they are in every respect. It was con-
sidered that this crystalline character, together with
durability, as instanced in Southwell Church, 850.;
uniformity in structure; facility and economy in con-
version; and advantage in colour, were all comprised
in the magnesian limestone or dolomite of lBolsover1
Moor and its neighbourhood, and was accordingly
recommended as the most fit and proper material to
be employed in the new Houses of Parliament. This
opinion was based upon a large number of experi-
ments upon the specimens of the ‘stones of the
various quarries visited by the Commissioners. The
specimens as delivered to them were in the form of
2-inch cubes. The composition of the stones was
determined by chemical analysis: their specific gravities
were taken; their weights, after having been dried
by exposure to heated air for several days; then their
weights after having been immersed in water for
several days, so as to become saturated; the object
being to ascertain the absorbent powers of the stones,
which was further tested by placing them in water
under the receiver of an air-pump, and then exhaust-
ing the air. The stones were also subjected to
_Brard’s process of disintegration for determining
how far a stone will resist the action of frost. Lastly,
the cohesive strength of each specimen, or its resist»
ance to pressure, was tested by the weight required
to crush it. This weight was applied by means of
the hydrostatic press, the pump of which was 1 inch
in diameter: 11b. at the end of the pump-lever pro-
duced a pressure on the surface of the cube equal to
2'53 cwt., or to 7106 lbs. on the square inch. The
weight on the lever was successively increased by a
single pound, and, in order to (ensure agradual .action,
a minute was allowed to elapse previous to the appli-
cation of each additional weight. The pressure at
which the stone began to crack was noted for each spe-
cimen, and also the pressure at which it was crushed.
The results of all these experiments, which are
stated for each stone,2 gave a decided preference to
the Bolsover magnesian limestone, which is stated to
be remarkable for its peculiarly beautiful crystalline
structure, while it is the heaviest and strongest of all
the specimens, and absorbed least water. Its compo-
sition is 50 per cent. of carbonate of lime, and 40 of
carbonate of magnesia; the remaining 10 parts con-
sisting chiefly of silica and alumina. = ' Professor Daniell remarks, that “if the stones be
divided into classes, according to their chemical com-
position, it will be found in all stones of the same

(1) Bolsover is a small market town in Derbyshire, on the
borders of the county of Nottingham, and about 145 miles from
London.
(2) The Commissioners also state for each quarry its name and
situation; the names and addresses of the freeholder, of his
agent, and of the quarryman ; the name of the stone; its compo-
sition, colour, weight per cubic foot; entire depth of workable
stone; description of the beds; size of blocks that can be pro-
cured; prices per cubic foot of block‘ stone at the quarry; descrip-
tion and cost of carriage to London; cost per cubic foot of the
stone delivered in London; cost per foot of surface of plain
rubbed work, as compared with Portland stone; and lastly, where
known or reported to have been employed in building.

class there exists generally a close relation between
their various physical qualities :-—-thus, it will be
observed that the specimen which has the greatest
specific gravity possesses the greatest cohesive
strength, absorbs the least quantity of water, and
disiutegrates the least by the process which imitates
the effects of the weather. A comparison of all the
experiments shows this to be the general rule, though
it is liable to individual exceptions. lint this will
not enable us to compare stones of different classes
together. The sandstones absorb the least water,
but they disintegrate more than the magnesian lime-
stones, which, considering their compactness, absorb
a great quantity. The heaviest and most cohesive of
the sandstones are the Craigleith and the Park Spring.
Amongst the magnesian limestones, that from Bol-
sover is the heaviest, strongest, and absorbs the least
water. Among the oolites, the Ketton Bag is greatly
distinguished from all the rest by its great cohesive
strength and high specific gravity.








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The above table gives the results of the chemical
analysis of 16 specimens of stone arranged according
‘750
STONE.
to their respective classes. The names of the
quarries are inserted under the general divisions of
the different species of stone, and the specimens were
considered as fair average samples of the workable
stone in such quarries.
Brard’s process for imitating the disintegrating
effects of the weather is a valuable test for stone.
When water is converted into ice an increase of bulk
takes place, and the expansion exerts an irresistible
force. If a cavity were left in one of the stones of a
building, and this from some cause were to become
filled with water, its expansion in freezing would pro-
duce on the stone the effects of gunpowder, rending
and destroying it; the effects would not be evident
so soon as in the case of gunpowder; for the mischief
occasioned to our buildings, our water-pipes, ewers,
bottles, &c., by freezing water does not in general
become evident until a thaw melts the ice, and allows
the water to escape. The usual action of frost upon
stone buildings is at the surface, where moisture
being absorbed, freezes into innumerable small
wedges, which, in expanding, destroy the cohesion of
the materials of the stone; and at the first thaw a
layer is thus removed, and a fresh surface exposed to
the weather. The effects are most disastrous among
mouldings and ornaments, which afi’ord cavities and
sheltered surfaces for the accumulation of wet.
Now the power which stones have of resisting
frost, must very much depend on their absorptive
power. Stones of similar composition, and even from
the same quarry, are acted on very differently by
frost; for while one stone soon displays the effects
of its action, another may remain uninjured for cen-
turies. By saturating stones with water and exposing
them to the action of cold as produced by freezing
mixtures, valuable results may be obtained. Such a
plan, however, is difficult and tedious, and M. Brard
was led to consider whether the expansive force of
some soluble salt in crystallizing might not be made
to imitate the action of water. After many trials he
found that sulphate of soda (Glauber’s salts) very
closely resembled in its action on stone the freezing
of water. In order therefore to determine whether
a stone which it was proposed to use in building
would or would not resist the action of frost, the fol-
lowing method was adopted :——-A saturated solution
of sulphate of soda was made in cold water, the
stone was immersed, and the solution boiled for half-
an-hour; the stone was then taken out and put into
a plate with a little of the solution. It was then left
in a cool place, and in 24¢ hours the stone was covered
with a snowy efllorescence, the liquid having dis-
appeared either by evaporation or by absorption.
The stone was then sprinkled gently with cold water
until all the saline particles had disappeared from the
surface. After this first washing, the surfaces of the
stone were covered with detached grains, scales, and
angular fragments, and the stone being one that was
easily attacked by frost, the splitting of the surfaces
was very decided. The experiment however was not
yet complete; the efflorescence was allowed to form,
and the washing was repeated many times during

5 or 6 days, at the end of which time, the bad
qualities of the stone had become fully established.
The stone was lastly washed in pure water; all the
detached parts were collected, and by these the ulti—
mate action of the frost upon the stone was estimated.
The effect of this process in various non-resistant
stones was remarkable. Some were found to have
deteriorated in the course of the third day; others to
have entirely fallen to pieces; those of which the
power of resistance was somewhat greater, held out
until the fifth or sixth day. Few stones, however,
except the hard granites, compact limestones, and
white marbles, withstood the trial during 30 con’se-
cutive days. For all practical purposes, however, 8
days are sufficient to test the resistant qualities of any
building stone.
The action of this process is as follows :—the boil-
ing solution dilates the stone and sinks into it to a
certain depth, nearly in the same way that rain-water,
by long-continued action, introduces itself into stones
exposed to the severity of our climate. Water, when
frozen, occupies a greater bulk than when fluid, and
the pores of the stone not being able to accommodate
the increased bulk of water, great pressure is ex-
erted among them, whereby a portion of the water is
expelled to the surface, and thus particles of the stone
are torn away. So in the saline solution: it is intro-
duced into the stone in a fluid state, and passing into
the solid form by crystallization, it occupies a greater
bulk, and a portion of it appears on the surface. The
repeated washings enable the salt to exert its full
amount of destructive action on the stone. Thus
the effect of congealed water and that of the eftlo-
rescence of salts in the disintegration of non-resistant
stones is very similar: water exerts its destructive
action on the stones only in a state of snowy effic-
rescence, which proceeds from below the surface to
the exterior, as in the saline eftlorescence; while water
at the surface of the stones may freeze into hard ice
without injury, and salts may crystallize upon them
with impunity.
Brard’s method may also be applied for ascertaining
the solidity and resistant power of bricks, tiles, slates,
and mortar. For example, during the winter season
M. Vicat composed 7 5 varieties of mortar with various
proportions of sand, and different methods of slaking
the lime. [See Mou'rxns AND Onnnn'rs] In the
following June these mortars were submitted to
Brard’s process. Many of them were attacked in 24
hours: almost all of them in 48 hours, and all, except
2, in three days. It was found that a mortar made
10 years previously of 100 parts lime, which had been
left exposed to the air under cover during a whole
year, and then mixed up into a paste with 50 parts of
common sand, withstood the trial admirably during
17 days, while the best stones of the neighbourhood
speedily gave way. In this case the solution was
saturated zo/zz'le 7202.‘, and so powerful were its effects
that stones, which had resisted the action of frost for
centuries, soon gave way when exposed to it. Vicat
calculated, that the effect of the saline solution on a
non-resistant stone, after the second day of trial, was
STONE—STONE, ARTIFICIAL.
751
equal to a force somewhat greater than that exerted
by a temperature of 21° Fahin, on a stone saturated
with water.
The action of the process upon bricks proved, that
whatever their qualities might be in other respects, if
imperfectly burnt they are quickly acted on. The
sharp edges of the brick, and then the angles, are first
rounded, and then the brick is reduced to powder.
Such is the action of frequent frosts on brick. Well-
baked bricks, on the contrary, retain their colour,
form, and solidity, under the test as well as by expo-
sure to frost. Ancient Roman bricks, tiles, and mor-
tar, and hard well-baked pottery, resisted the process
perfectly; as did also the finest white statuary marble,
while common white marble was speedily attacked.
Portions of some of the buildings of Paris which had
been exposed to the weather during 20 years without
injury were tested by Brard’s process, and were un-
affected by it. A large number of experiments were
made on stones from the different quarries of France:
the action of the salt was continued for 7 days, and
the results were recorded: it was then continued for
It days, and the results compared with the preceding
ones, when it was found that the stones marked as
good in the first set of experiments retained their
character, while the bad stones continued to deterio-
rate rapidly. By this process the different qualities
of stones from the upper and lower beds of the same
quarry are easily determined; the stone from the
upper bed being often non-resistant and that from the
lower resistant, while to the eye both kinds of stone
appeared to be identical.
One great advantage of this process is the power
which it gives to the architect of selecting a hard
durable stone for those parts of a building which are
most exposed to the action of the weather, such as
the cornice, the columns and their capitals, which are
more exposed to the destructive action of rain, bail,
and damp air, than the flat surface of a wall.
A Commission appointed by the Royal Academy of
Sciences for inquiring into the value of Brard’s pro-
cess, published a set of directions for carrying it out
for the benefit of architects, builders, master masons,
landed proprietors, and others. These directions may
be of value to some of our readers.
1. The specimens of stone are to be selected from
those parts of the quarry where, from certain ob-
served differences in the colour, grain, and general
appearance of the stone, its quality is doubtful.
2. The specimens are to be cut into 2-inch cubes
with sharp edges.
3. Each cube is to be marked or numbered with
Indian ink or scratched with a steel point; and cor-
responding with such mark a written entry is to be
made of the situation of the quarry, the exact spot
whence the stone was extracted, and other details
relating to the specimen.
4:. Sulphate of soda is to be added to rain or dis-
tilled water until a saturated solution is obtained,
which is known by a portion of the salt remaining at
the bottom of the vessel after an hour or two, during
which the solution must be repeatedly stirred.

5. Put the solution in an earthen pipkin over the
fire: when it boils put in the specimens one at a time,
and let them all be covered by the solution.
6. Continue the boiling for 30 minutes.
7. Take out the cubes one at a time, and hang them
up by threads, so that they touch nothing. Place under
each specimen a cup or gallipot with a little of the
solution iii which the stones were boiled after having
strained it clear.
8. If the weather be not very damp or cold, the
surfaces of each stone will in the course of 2A hours
become covered with small white needles of the salt.
Plunge each stone into the vessel beneath, so as to
wash off the crystals: repeat this operation 2 or 3
times a'day.
9. If the stone be one that is capable of resisting
the action of frost, the crystals will abstract nothing
from the stone. If the stone be non-resistant the salt
will chip off particles of the stone which will be found
in the cup below; the cube will soon lose its sharp
edges and angles, and by about the fifth day from the
first appearances of the salt, the experiment may be
considered at an end. As soon as the salt begins to
appear at the surface its deposition may be promoted
by dipping the stone into the solution 5 or 6 times
a-day. '
10. In order to compare the resisting powers of two
stones which are acted on by the solution in different
degrees, collect all the fragments detached from the
faces of the cube, dry them and weigh them, and the
greatest weight will indicate the stone of inferior
resistance to frost. Thus, if a cube of 24 inches of
surface lose 180 grains, and another similar cube only
90 grains, the latter is evidently better adapted to
building purposes than the former.
STONE, ARTIFICIAL. Several of the cements
described under Monrxns AND Cmumv'rs may be re
garded as artificial stones, and are in fact used as such.
The important distinctions between plasters and ce-
ments were pointed out in that article. The cements,
whether hydraulic or not, readily part with their car-
bonic acid and water on the application of heat, and
become reduced to lime, when, by a peculiar treat~
ment and admixture generally with silicate of alumina,
a material is produced which rapidly absorbs the
water required for its solidification, and it hardens
into a cement or artificial stone. There are many
such cements of which the basis is oardoizale of’ lime.
Plasters, on the other hand, have for their basis gyp-
sum, or salplzaie of’ lime, which, on being burnt, parts
with its water of solidification without being decom—
posed. The addition of water to the ground powder,
as in the case of plaster of Paris, reproduces the solid
form; but by the addition of certain salts of alumina,
borax, and potash, the ‘hardness and compactness of
the newly-formed stone are greatly increased, and its
absorbing power modified. The patented plasters,
known as Pai'z'aa, Keeae’s, Mariia’s, and other ce-
meals, are formed of such materials in certain propor-
tions, as stated under Monrxns AND Cnrrmvrs, where
the method of forming soagliola is also noticed.
A method of forming artificial stone, different in
752
STONE, ARTIFIOIAL——STORAX.
principle from that on which plasters and cements
are made, has been introduced by Messrs. Ransome
and Parsons of Ipswich. “ This material is a com-
pound, consisting of grains of sand, pebbles, portions
of limestone, marble or granite, clay, or, indeed, any
other material, cemented together by a true glass,
obtained by dissolving flint in caustic alkali in a
boiler at a high temperature, mixing up the materials
with this solution into a paste of the consistence of
putty, moulding this paste into any required form,
and after slow air-drying, burning the articles thus
manufactured in a kiln at a bright red heat main-
tained for some time. In the course of this process
the alkali combines with the free silica, and forms
a kind of glass, so that the materials become ce—
mented together by a substance which does not admit
of the smallest absorption of moisture, and is conse-
quently absolutely unattackable by the frost. It
also resists every other kind of atmospheric action,
and is extremely hard. It possesses, besides, the
great advantage of not contracting sensibly during
the last process of baking.” 1 This stone is, however,
subject to one great disadvantage, viz. some of the
salts of soda contained in it are liable to effloresce,
and thus greatly to disfigure the work. In preparing
the solution of silicate of soda, large rough fiints
from the chalk pit are used. They are suspended
in wire baskets in a high-pressure boiler, the pressure
being from 60 lbs. to 100 lbs. on the square inch.
For about a ton or a ton and a half of flints, about
a quarter of a ton of caustic soda is required (about
56 per cent. of alkali). The fluid silicate of soda is
drawn off every 48 or 56 hours, the quantity being
about 200 gallons: it is then evaporated down to
a sp. gr. of 1165, when it is fit for use.2
With the materials above indicated are manufac-
tured various kinds of stone for garden work, for
paving, and a porous substance for filter stones: the
latter may be made of any required size; they are
cheap, and very effective: they may be cleaned with
ease, and be so contrived as to be applied without
a reservoir to filter water delivered to houses by the
system of constant supply.3 Scythe stones and
grinding stones of various kinds are produced by this
method, sand, in certain proportions, forming the
base: such stones wear with remarkable uniformity.
By employing finer descriptions of sand, clays, &c.,
all kinds of ornaments are made, such as columns,
capitals, balustrades, mouldings, cornices, chimney—
pieces, &c.; also fioorings, steps, and pavements of
every design; and by using various metallic prepara-
tions any desired colour may be imparted to them.
Orsi’s brown avzelallz'c law is composed of broken

(1) Jury Report, Class XXVII.
(2) It is proposed to apply this solution to wood-work, and
.other similar materials, and to precipitate the silica in the pores
by afterwards laying on a weak acid. Articles may thus be ren-
dered fireproof and indestructible. This application of soluble
glass is, however, every old one: it was used in some of the
German theatres many years ago.
(3) The cost of such a filter, passing 300 gallons per day, is
21. 10s. Small filters are prepared for the use of travellers at the
cost of 5s. each. Permanent ascending filters are also prepared
with the same material.

gravel or stone 3 parts, pounded chalk 2 parts, tar
1 part, and wax 315th part. The tar is first melted
in a caldron, and the other ingredients, together
with a mineral colour, are added. The artificial
stone thus formed is cast in moulds, either into solid
blocks, or into hollow vessels for troughs and tanks.
Pipes are formed by wrapping a core of wood in
paper, and rolling it over a flat table covered with
the lava in a fluid state; when a good coating is thus
taken up, 3 or more iron ribs are attached lengthways
at equal distances by winding wire round them: a
second coating is then rolled on so as to cover the
ribs and the wire. When cold, the wooden core is
withdrawn. For ornamental bricks, tilesfand quarries,
an ornamental melrillz'e law is composed of ground
flint 2 parts, marble broken small 3 parts, resin 1
part, wax ila-th part, colouring matter Egaths part,
(such as cobalt for blue, yellow ochre for sandstone,
red ochre for red granite, 850.) Ornamental files of
various colours may be manufactured by casting in
this lava, in suitable moulds, pieces of various colours.
Suppose a tile were to be formed of a blue, yellow,
red, and grey pattern, a blue piece is first cast, and
allowed to cool: it is then placed in the centre of the
mould from which the yellow piece is to be cast;
yellow lava is then poured in round the blue piece,
and when the two colours are united they are trans-
ferred to the mould for the red pattern; the red lava
is then poured in round the blue and the yellow: the
three colours are next placed in a fourth mould, and
the outside piece of grey is added. All these pieces
are cast on a fiat-iron, with those surfaces undermost
which are intended to form the top surface of the tile,
and, for the sake of economy, the coloured portions
are not more than from %g to 1 inch in thickness, a
backing of brown lava being added to give the re-
quired thickness and strength. When the tile has
become set and cold, it is ground and polished by
a flat stone with sand and water.
STONEWARE. See Porrnnr AND PORCELAIN.
STOP. See ORGAN.
STORAY, a balsamic substance exuding from
incisions made through the bark of a small tree,
Sigma: ofiicz'rzalz's, growing in the Levant, Palestine,
Syria, and Greece. The storax of commerce includes
numerous substances of variable character and com-
position, mostly artificial. Real storax is rare: it
occurs in compact masses, fragrant, and of a rich
brown colour, interspersed with white tears, hence
called amygtlaloz'cl slomzr. It was formerly imported,
wrapped up in a monocotyledonous leaf, under the
name of cane or reecl slyma: (Slymx calamz'la). In
the drug market two substances, named storax, are
met with. One, called Slyma' ligm'rlus, is usually of
a black, brown or grey colour, and of a disagreeable
odour: the other, called Sly/mm calamz'la, is black,
brown, or purplish; pulverulent or granular, or in
agglutinated lumps. It is said to consist often of
pulverized rotten wood imbued with liquid storax;
or fine sawdust impregnated with a substance re-
sembling coal tar.
Liquid storax, on being distilled, yields an oil con-
STRENGTH OF MATERIALS.
753
sisting of 2 atoms carbon, with 1 of hydrogen. It is
named styrole, and is convertible by heat into mommy/-
role, a solid, transparent, glassy, fusible substance, and
having the same high refractive power as the original
styrole, to which it may be restored by distillation at
a high temperature. Styrole is so volatile that the
oily spots made by it on paper disappear at common
temperatures in a few seconds. Its sp. gr. is O 924::
it boils at about 293°, and its formula is said to be
0 6H,, and is isomeric with benzoine.
STOVE—See WARMING AND VENTILATION.
STRASS—See GLASS, Section IV.
STRAW-PLAT—See HAT.
STRENGTH OF MATERIALS. The fitness of
different solids to diflerent mechanical uses, their dif-
ferent kinds of strength and stiffness, and the forms
and dimensions required in them to answer their ends
without danger and without waste, all depend on the
forces inherent in their particles, by which those par-
ticles act on each other and maintain their connexion.
All bodies are known by many proofs to be composed
of particles at distances asunder, which, although far
below any means of artificial measurement, are very
considerable compared with the bulks of the particles
themselves, if they have any bulk, for we have no
proof that they are not absolutely mathematical
points. These particles, whether solids or points,
are kept at particular distances apart by the equili-
brium between the sum of all the forces tending to
bring them nearer, and another force tending to sepa-
rate them, and which we therefore call repulsion. The
forces tending to bring them together may be inhe-
rent in themselves, or external to them, and trans-
mitted from any distance by this same repulsion
among all the surrounding particles. In the simplest
known form of matter, viz. gas or air, they are wholly
thus transmitted from a distance. In a confined
portion of gas or vapour, the only force apparently
inherent in the particles, is that of repelling their
neighbours. We say their may/locum, because the
phenomena are incompatible with such a repulsion
between any particles, however near, that are not new!
to each other. This repulsion is the only force dis-
coverable in a gas so confined, and must be balanced
by the resistance of the confining vessel. But in the
open atmosphere, we find it is balanced by a second
force inherent in the particles, but too small to be per-
ceptible except in great quantities together, viz. their
attraction or gravitation to the earth. The existence
of masses wholly gaseous, as comets, shows also that
gas gravitates to gas; and we conclude that its par-
ticles (like all others that we call matter) attract‘ at all
measurable distances, from the breadth of the solar
system down to that of a hair, although, at the great-
est distances to which we can let adjacent ones recede,
they repel. There must evidently be a distance then,
less than ahair’s breadth, at which they pass from the
domain of one law into that of the other, and neither
attract nor repel; and this must be their natural dis~
tance, horizontally, at the top of the atmosphere.
We say Izorz'zorzzfaléy, because vertically they must be
nearer, namely, near enough to repel the next layer
VOL. II.

below, with a repulsion equalling their gravitation to
the whole mass of the air and earth. Thus every fluid
must, at its surface, be denser in a vertical direction
than horizontally, but the horizontal distance of the
surface particles must always be the same in the same
gas, whatever he the depth of the atmosphere below,
and whether attached to the largest or the smallest
planet, or to none. Anywhere below the surface they
are of course near enough to repel their neighbours all
round, and nearer the deeper below the surface ; and
although the air here at the bottom has been rarefied
by pumps above 1,000 times, that is, its particles
have been allowed room to recede to more than
10 times their natural distance, this is not far enough
to lose their repulsion or rest together as at the
top of the atmosphere. We know not how many
times their surface distance may exceed this, and yet
that maximum distance, we conclude, cannot be a
hair’s breadth; because the lightest bodies which we
can handle, when‘ delicately suspended or floating,
gravitate to each other, and although enveloped in
films of this repellent air, as can be proved by their
refusing to be touched by other fluids in which they
are immersed, yet they approach and attract till they
are nearer than a hair-breadth, or in what we com.
monly call contact.
The next simplest form of matter to the aériform is
the liquid. In this, also, the particles at the surface,
if subject to no external pressure from gas, are at a
neutral distance, where they neither attract nor repel,
but within which they repel, and beyond which they
attract. Yet this distance is many times less than
that at which they would behave in the same way as
gases. The air we breathe, which we have seen has
its‘ particles, we know not how many more than 10
times, neareixthan their first neutral distance, has
certainly had them brought, by artificial pressure, 41
times nearer than this 5 and so far was the repulsion
from diminishing, that it seemed increased“ as much
as the density, or 64. times. But most other gases,
before being compressed to this extent, have some
particles brought nearer than the distance at which
their repulsion is greatest, nearer even than that at
which it has again diminished to nothing, and changed
into a new attraction, so that they are brought by this
second attraction, through the whole range of its
action, to the distance at which it changes into a
second repulsion, and this is the distance at which
they would rest as a liquid in vacuo. But in these
cases the external pressure brings them a little nearer
still, to where this new repulsion is enough to ba-
lance it, or to equal the repulsion of the other particles
that remain as gas. So also, in the open air, no par-
ticles, whether of gas, liquid or solid, are exactly at
a neutral distance, but within a repellent one, and just
so far within it that their repulsions (measured in lbs.
per square inch) are all equal; although some, such
as air, are in their first repulsive distance, and others
(such as water) in their second. If the particles of
water he removed to just 12 times their ordinary
distance (and have the temperature necessary to
keep them there), they will repel almost exactly as
3 c
754'!
STRENGTH OF MATERIALS.
much by gaseous repulsion as they do in the ordinary
state by liquid repulsion; that is, they again balance
the atmospheric pressure. This difierence is not so
great as 12 to I in any other known liquid and its
vapour. In all that have been tried it is less than 8
to 1, in none much less than 6 to 1. But we must
not suppose that these at all approach the ratios
between the two neutral distances, or those at which
the particles rest at the surface of an unpressed liquid
and an unpressed gas of the same matter. The differ-
ence of these cannot be known unless we had ex’-
amined matter in the latter state; but it would
‘certainly be much greater than between the same
liquid and gas when equally repellent, however small.
that equal repulsion be, or, in other words, however
small the equal pressures under which we compare
them. It was shown (see STEAM) that the less the
pressure common to any water and its vapour, the
greater is the difference of their densities; and that
Gay Lussac found this difference, under a very small
pressure, as 600,000 to 1, or the distance of particles
almost as 85 to 1. The reason is, that any change of
pressure makes an immensely greater difference in an
air than in a liquid. In other words, the same repul~
'sion is elicited by a vastly less approach within their
respective neutral distances, of the liquid particles,
‘than of the gaseous ones. When at their second
resting distance then (or that at the surface of an
unpressed liquid) any‘ disturbance therefrom brings
into play vastly strong—er attractions and repulsions,
than a like or proportionate disturbance from their
first or gaseous resting distance would. We say stronger
attractions as well as repulsions, because although we
‘cannot measure the former, it can be proved that at
the limit the disturbance of a thing either way, by
equal forces, must be equal; which means that the
less the disturbances each way, the more nearly equal
do they become, and .that they may be so little as to
be more nearly equal than any proposed ratio. Thus
although a piece of Indian-rubber may be stretched,
perhaps, two inches by the same force that would be
needed to compress it only 1 inch, any less force
would produce a stretching and a compression more
equal than as 2 to l, and by comparing changes small
enough, we shall presently find them sensibly propor-
tional to the forces producing them; which is what
Dr. IIooke expressed by his famous law, at teasz'o sz'c
via, and which applies to all the following matters. So,
again, although a removal of all pressure allows air to
expand, we know not how many more than 1,000
"times, while a doubling the pressure only reduces it
I-half ; yet, if, instead of 15 lbs. per inch added and
'taken away, we compared the effects of 1 oz. per inch,
we should find them sensibly equal, and sensibly half
those produced by 2 oz. per inch. But even these
would have more effect on air than the greatest forces
which we can apply have on liquids. The removal of
,‘allpressure only causes water to expand as 22,000 to
22,001, or its particles to reeede 3% further apart.
So small a change, either way, from their neutral dis-
tance must excite forces sensibly equal, for it can be
‘measured‘that 10 or even 50 times this compression

elicits sensibly just 10 or 50 times the repulsion. By
the common pressure, the particles at a watery sur-
face are brought m nearer than in vacuo, and as
near as at 33 feet below the surface in vacuo. At
33 feet deep in the sea they are nearer by another
66,000th, and so on.
The water in a hanging drop must be rarer than at
an ordinary surface; 'but it would take a drop or
thread 33 feet long to pull the particles at its root
as much as they are pressed together by the air, or
allow them to attain their neutral distance. Of
course, they are never beyond this, or attralieat, ex-
cept in a drop hanging in vacuo. As 33 feet to the
depth of such a-drop, so is @3300 to the fraction of
their natural distance that the particles are pulled fur-
ther asunder by it. Hence the extensibility of water
(lineally, or in length) may be about a 100,000,000th;
that is, it may be stretched so much without breaking.
We see then that a removal of the particles of
water m nearer or further apart, brings into play
attractions or repulsions that, between two particles
only, are as great as the gravitation between the
whole earth and a line of such particles extending 33
feet; which may give us some idea how enormously
the first attraction of all particles (or gravity), and
the first repulsion (or that causing gaseous elasticity),
are surpassed in energy by the‘ forces that keep the
particles of liquids, and far more of solids, in equili—
brium at their natural distances. It shows, too,
that although external forces must be keeping them
mostly at a little more or less than these distances,
(viz. the atmospheric pressure, keeping nearly all at
repelleat distances, but pulls of all kinds keeping a
few at attra/zeat ones,) these effects are all so very
minute, that we may regard the actual distances of
all particles (not gaseous) as being one of their nea-
tral distances, within which they repel, and beyond it
attract.
That there are several of these alternations from
attraction to repulsion, in bodies nearer than a hair’s-
breadth, may be easily shown with two very plane
pieces of plate-glass. First, by floating them on
mercury, their own gravitation will ‘bring them into
what we call contact, such as to cause them to strike
with a sound. Yet, even the gravitation of one to
the whole earth (instead of to the other piece) does
not always bring them near enough to rub with
sensible friction; for one may be laid on the other,
and, although J57th of an inch thick, will float over it,
upheld by‘ a repulsion equal to its own weight of
more than 2 drachms per square inch; and the effect
is too lasting to be due to air unable to escape
in time. New wind athread of the silk-worm over
one piece, so that no part of the thread may cross
another; and when the other piece is brought by
slight pressure as near as the thickness of this thread,
(perhaps rather nearer by its compression,) they will
attract enough to keep a thick lower plate suspended.
Lay them down, and without the silk this same pres-
sure will bring them nearer, near enough to be in-
clined 15° without sliding off, the friction being about
gth of the pressure, the ordinary friction of glass on

STRENGTH OF MATERIALS.
‘755
glass. In this state they are not near enough to
produce the colours of thin films; or only, with a
heavy upper plate, the pale pinks and greens that
Newton showed to require 60 to '70 millionths of an
inch of air. The upper plate, then, is again upheld
by repulsion, and it will be found that all these
colours are produced within the range of a secoml
repulsion, which increases in energy up to some hun-
dreds of pounds per square inch, the pressure required
to produce the final black colour, or make the inter-
mediate film invisible, i.e. to bring or keep the glasses
within a millionth of an inch. But- when the pressure
has exceeded, at any point, 1,000 lbs. per inch, we
may remove it; they are in a third allm/zezzt distance,
if suspended, and the parts within this distance are
kept together by far more than the atmospheric
pressure. The friction, or resistance to lateral move-
ment, is also so great that we may break in trying to
slide, much more to pull them apart; and being in
optical contact (zlexnearer than a quarter the interval
of a wave of light), they might pass for one piece.
Not so, however; for without stopping to inquire
whether air permeates this invisible fissure, we shall
First cohesion
-_-_~___
Second cohesion .._.____
Third cohesion
Fourth cohesion
Fig. 2085.
Boscovich, the great investigator of these forces of
matter, therefore observed that their whole law must
be expressed by some such curve as this, with an un-
known number of doublings, whose distance right or
left of the line zm, at any point would represent the
amount of attraction or repulsion between two par—
ticles whose distance is supposed to be measured from
z to that point, on a greatly magnified scale. Thus



find that water does, as quickly as the fissures of
sugar or cotton, and separates them so much further,
that although still too near to reflect light, and still
attracting, they are easily separated. Now, as no
pressure which we can apply to them before present-
ing the water will prevent its entry, or make them
behave to it as one piece, this pressure is plainly
resisted by (or brings them within the domain of) a
l/zz'rcl repulsion. Whether the next, or fourth allme-
lion, would be that which unites the particles of the
same piece, we cannot tell. There must be a pressure
that would mend broken glass as well as tallow, or at
freezing as well as at a white heat, and the fine
plates cast at St. Gobin are said to have sometimes,
when left long pressed together, become absolutely
inseparable, and been cut and polished as one. What-
ever the numbers of these attractions and repulsions,
they must be equal, because, as the first, extending
to all space, is an attraction, so the last must be a
repulsion—that by which simple solids like glass re-
sist compression, and which there is every reason to
suppose insuperable, or increasing without limit as the
particles approach.
Gnavr'm'rron, diminishing as the
square of the distance, and ex- _
tending into infinite space.
First repulsion, or gaseous
elasticity.
Second attraction.
Second repulsion.
--_-—--__.___.__ -—
Third attraction.
Third repulsion.
Fourth attraction
Fourth repulsion.
CURVE OF MOLECULAR FORCES.
gravitation, increasing from all distances up to the
proximity of zm (where it is a maximum), is expressed
by the curve above m being a hyperbole, such as per~
petually approaches the straight line, but never
reaches it. ZA is the distance, less than a hair’s-
breadth, at which particles cohere, on the top of the
atmosphere, where their weight balances their elas-
ticity. All the points A, a, n, b, c, e, 1), are neutral
3 c 2
‘756
STRENGTH OF MATERIALS.
points ; but a particle can only rest at such points as
A, B, c, and 1), because at a, t, or e, the slightest move-
ment gives preponderance to one of the forces that
tend to remove it therefrom. It is like the fabled
Mahomet’s cotfin, between the attraction of the earth
below and a magnet above; for though there is al—
ways a point ‘where their attractions are equal, no
body could rest there, as it could between any two
repulsions, and as a needle does in an electrical helix.
The last branch of the curve is shown, like the first,
ever approaching and never reaching 2 .2, because the
last repulsion must be insuperable; but it is most
likely, and consistent with natural analogies, that, as
the alternations grow more and more frequent, every
force being confined to a far shorter range of distance,
as well as far stronger, than the preceding one, their
number would be infinite, or the curve make closer and
closer turns, departing at length beyond any assign-
able distance from D z, innumerable times within the
distance D z, or that dividing the particles in an
impressed and unstretched solid.1
These alternately attractive and repulsive distances
may very probably be the same in which the rays of
light, passing within a hair’s-breadth of the edges of
bodies, are known, by the phenomena in their sha-
dows, to be, some attracted and others repelled.
The next simplest form of matter after the liquid,
seems to be that of glass, resin, bitumen, and other
solids that break with curved polished surfaces, and
with equal ease in all directions. If really incapable of
crystallizing, we must conclude their particles to have
no polarity, that is, no sides or corners, and no in—.
equality of these forces in different directions. In all
crystals there is such inequality, and the particles ‘
are all arranged, by virtue of it, with like parts in like
directions, in such perfect regularity, that they can
only break with plane surfaces. The simplest break in
three or more directions all equally inclined, and the
figures when perfect have length, breadth, and height
equal, as in the diamond, sea-salt, alum, and finer-spar.
These are the fourth simplest form of matter. The fifth
consists of crystals wherein the molecular forces in
one direction are different from those in all directions
perpendicular thereto, but alike in all the latter, and
in intermediate directions varying only according to
their inclination to this one, called the axis, so as to
be alike in all that are equally inclined to it. Such
are quartz and calcareous spar. Lastly, there are
crystals wherein they vary in all directions, and the
perfect form has length, breadth, and height all dif-
ferent, of which kind are nitre and sulphur.
The seventh simplest kind of matter, and simplest
of what may be called composite solids, is the erg/stal—
line, is. a congeries of imperfect crystals adhering in
all directions; as marble, and probably all cast metals,
although we can rarely see this with the naked eye in
any but cast-iron. Here the cohesion of crystal to
crystal (which is a very different and far weaker one

_ (1) The mathematical reader will readily find very simple equa-
tions producing curves answering to this description, so that the
whole. law, although probably undiscoverable, may be as simply
expressible as that one result of it called gravitation.

than that of particle to particle) constitutes the whole
practical strength. The multiplicity and confusion of
the polarities makes it very equable in all parts and‘
directions, even more so than in the glassy bodies, so
that these are practically the most uniform solids.
Probably clay, brick, and most minerals that break
with rough or dead faces, are of this class ; but being
unable, even with microscopes, to examine them near
enough to see the glittering of crystalline planes, we
call them granular, not knowing what the grains
may be. Often they are, doubtless, ruins of crystals,
worn or rounded in various degrees, even to pebbles
or spheres, and then brought by pressure within an
attractive distance of each other. But they are pro-
bably oftener masses themselves minutely crystalline,
or granular, or conglomerated (i.e. having a cement
between their grains), and their grains again granular,
in we know not how many descending orders ; just as
geological ruins and reconstructions may have pro-
duced gravel whose pebbles are of conglomerate,
whose nodules are of oolite, whose spherules are of
limestone, whose grains are of some crystalline marble
and each containing innumerable crystals. The finest
sand-grains are really as rugged and complex forms
as cliffs or mountains to the naked eye; and such
fine—grained and seemingly simple solids as Turkey
bone and Tripoli polishing-stone are composed of
animal skeletons, a hundred not reaching a lineal inch,
that is, a million not filling a cubic inch. But how-
ever many the orders of grains in a composite solid,
it is only the weakest cohesion, that between the
largest grains, which constitutes its practical strength.
In a conglomerate, indeed, or cemented sandstone,
the cement may, by being stronger than these grains,
constitute the whole value of the material, which
would then be more useful with the weight of the
grains away, and replaced by air or compressed gas,
as in bodies that while solidifying have been leavenecl
by escaping bubbles. Pumice-stone, a volcanic glassy
body minutely leavened, would be of immense utility
in architecture, wherever it is common. Many ancient
churches, especially the cathedral of Constantinople,
were by its means vaulted, in fine and useful modes,
not exactly imitablc without so strong and light a
material.
Differing from the merely granular, there are two
opposite forms of composite solid, whose use depends
on the first or practical cohesion being difi’erent (either
greater or less) in one direction than in all others.
When less in this one direction, the body is laminar,
as slate or mica; and when greater in one direction
than the rest, it is filzrous, as pumice-stone. These
textures are thus the converse of each other; and
.although producing a tendency to be divided, the one
by clefts in a certain direction, and the other in all
directions perpendicular to a certain plane, they do
not imply the existence of a definite number of plates
or fibres. Minerals, as the above, are not composed
of, but only separable into, plates or fibres, and
merely from this polarity (or difference depending
on direction) in the first cohesion. The ultimate
or atomic cohesion leads, in crystals, to something
STRENGTH OF MATERIALS. ~
757‘
similar, in what are called the directions of cleavage;
but of these there are three or four, never an indefinite
number as in fibrous bodies, nor a single one as in
truly laminar ones; although they nearly approach
the latter when one cleavage is very much more de-
cided than the rest, as in mica.
But in organic bodies, as wood, hemp, bone, and
shell, the fibrousness or lamination is a structure, and
not simply a property; and the number and size of
fibres or plates is definite. The fibres too, which
make up the bulk of nearly all organic materials that
are used mechanically, are variously and infinitely
complex in their own structure; either tubular, or
chambered by partitions at long or short intervals, or
perforated by many longitudinal canals, and their
solid parts built up of a second order of fibres, of
ramifying or of spiral vessels, cells, ‘vesicles, 8:0.
Thus the proportion of simple solid to void is ren-
dered vastly less than in the most leavened pumice-
stone; and being all arranged with infinite wisdom
to yield the utmost advantage of its strength, and not
a particle needlessly introduced, the whole edifice
becomes often, as in cork, three or four times lighter
than potassium, the lightest known simple or compact
solid; and incomparably stronger, weight for weight,
than any artificial combination of mineral materials
can ever possibly be.
As the simplest solids are commonly the hardest,
most crystals are intractably so; and hence we use
few crystalline bodies mechanically, unless either the
adhesion of crystal to crystal is rather weak, as in
marble and granite, or the crystals some of" the. soft-
est, namely, those of carbonate of lime and the seven
malleable metals. Malleability consists in a deficiency
of the forces that oppose the sliding of particle over
particle, compared with the attraction that opposes
their separation, or an unusual excess of the latter
over the former. Hence, the minutely crystalline
mass in which these seven, remarkable solids, like
most others, cool from fusion, may by llanznzerz'nghave
all its crystals so flattened. out as to approach the
texture of a laminar solid, or by rolling or zoz'redraw-
ing so extended in one direction as to become fibres ,1
and it is in this artificially fibrous state that they are
most used, because the practical or first cohesion (that
between the fibres intowhich the crystals are ex-
tended) is increased,_at least in one direction, and the
nllz'rnnle cohesion (that which made the crystals hard)
is advantageously diminished; for, as no cohesions
stronger than the first add anything to the practical
strength, but only to the difficulty of working, their
strength is an actual disadvantage, unless the material
be either shaped‘ in the liquid state (as cast-iron), or
used only with such a roughness of finish as shall
never necessitate cutting the crystals or grains (as
granite and sandstone), or they be so fine as to admit
any degree of finish without it (as in clay). Thus, no
one would prefer, where they are equally accessible,
and have the same practical strength, sandstone,
whose grains are harder than any glass, to marble or
limestone, whose grains are softer than most iron.‘
Besides all this, it is remarkable that all the malle-

able metals, except lead, ‘are by these “operations com»
pressed in the directions of pressure without an
equivalent extension in any other ;_ that is, while the
particles forced further apart return to their former
distance by attraction, those brought nearer together
by the direct action of the hammer, or the constric~
tion of the wire-drawing hole or rollers, do not all
return, but are, some or all, brought into a new
attractive distance; so that the number of particles
in a given bulk, or the density of the metals, is in-
creased, although they have never been enclosed all
round, often in iron a tenth, or as much as water would
be by a pressure of 220-0 atmospheres. The former
bulk is. not regained even by any addition of heat,
short of what will fuse, and leave them to a new
crystallization; although a much lower heating re-
stores something lost during the compressive treat-
ment, viz. their softness and malleability, which had
_given place to hardness and brittleness, so that this
heating or annealing is necessary from. time to time
to admit the carrying on of the condensation to any
great extent. And as every operation that condenses
renders them nor (sometimes red-hot) as well as
harder and more brittle, and cannot be repeated, nor
heat again elicited by any hammering, until they
have both disposed of this heat to surrounding bodies
and regained their softness and malleability (but not
their bulk) in the fire, it is natural to conclude that
as much caloricas was forced out by the former con-
densation must be reabsorbed and fixed in. them before
another is‘- possible; and yet it does not remove the
particles (or only a_ few of them) beyond their dimi-.
nished spheres of attraction.
It has by some. been thought very unaccountable
that the increase of strength- gained in these pro—
cesses should be not in the direction in which the
particles are squeezed into a new cohesion, but only
in that in which they remain at. or beyond their
former distance, viz. in the length of the bar, sheet,
or wire. But, in fact, the cohesive force, i.e. the
attraction, which resists extension, is not even in this
direction increased, but, if anything, diminished. The
metal is not more difficult to slrele/t, but only to pull
asunder. It is even less elastic to resist or recover
from extension, and is. stronger only because more
extensible ;, i.e. because the attraction, though weaker
at any given, distance, extends through a greater
range of distance, and so acquires a greater force.
before changing intorepulsion. That a body may be
broken, some particles must be pulled to the distance
where some attraction reaches its maximum. What-
ever force can dothis, will of course pull them
through the remainder of its range, and also through
all succeeding attractions, if- we suppose them, like
the two last (liquid cohesion and gravity), and like all
those observed between the glass plates, to have their
maxima rapidly less and less as bodies recede. But
this need not be supposed to be universally the case ;
and one effect of forging seems to be the forcing par—
ticles asunder in the direction of the length of the
body, past the maximum of the attraction that ori-
ginally confined them, so that they are carried out to
758
STRENGTH OF MATERIALS.
the next attractive range, which happens to be not
only more extended than. the former, but to have a
greater maximum. That a greater maximum may
occur exterior to a lesser one, appears from the fact
that hardly any solid can, after pulling asunder, be
mended by no greater a force pressing the pieces to—
gether than that which separated them; although the
repulsion which prevents this is exterior to the at-
traction which has been overcome.
An arrangement of the particles so as to be thus
between the limits of different spheres of force in dif-
ferent directions or parts, must be totally incompa-
tible with the formation of a crystal; so that perhaps
a liability to such arrangement, arising from there
being an unusual number of alternations of attraction
and repulsion in a small range of distance, may be the
cause of some bodies crystallizing only on the mi-
nutest scale and in the most imperfect manner (as
malleable metals, wax, &c.), and others not at all, as
those which are called glassy: consistently with
which, the density of glass is found to vary gradually
from part to part of the same piece, a phenomenon
utterly without parallel in the most coarsely or irre-
gularly crystalline masses. Some bodies indeed, as
sulphur, can crystallize in two (or perhaps more) in-
compatible modes, or classes of forms not derivable
from each other; doubtless, at two different neutral
distances of the particles, which will be shown (if it
is so) by the two varieties of sulphur, &c. having a
definite and constant difierence of density.
' The existence probably of several slightly different
neutral distances, in the case of the metals, seems con-
nected with one very singular property, their causing
electric sparks drawn from them to yield light, not
composed (like that of ‘ the sun or aflame) of waves
of all possible lengths within certain limits, but of 6
or '7 definite lengths only, which are all different in
each metal, and when an alloy gives the spark, the 13
or 141 due to both metals appear all together.
Solidity consists in that force which we have said
is small (compared with the others) in malleable
solids, namely, the force that opposes sliding of par-
ticle over particle; that is, neither an attraction nor
a repulsion, a force acting neither to nor from a par—
ticle, but tangentially to any circle drawn round it;
like the force by which a magnet and an electrical
wire move each other. We have no proof, however,
that it ever acts as a moving force, or brings particles
back to or towards a position from which they have
been disturbed, as all the attractions and repulsions
do. It may, for aught we know, he only a resistance
to movement, like friction, which, as we saw by the
experiments of the glass plates, becomes rapidly
stronger at each successive neutral distance. At the
first support by repulsion it is imperceptible, for one
plate slides off the other however level we place it.
At the second it seems about i- of the weight or pres-
sure which the repulsion is at any time supporting.
At the t/iircl it is so great that one will not slide off
the other in any position, nor by a much less force
than would overcome their attraction by direct pull.
This third friction then exists independently of pres-

sure, or not only in the repulsive but at the nen/ral
distance; and so in the second, or ordinary friction,
it has been proved that the whole resistance may be
divided into two parts, one proportional to the pres-
sure, and the other constant however small the pres—
sure, so that this latter would remain were there no.
pressure or repulsion, i. e. at the neutral distance.
Now it is a resistant force, like this latter, operating
at some of the nearer neutral distances, that distin—
guishes solids from liquids, or constitutes solidity.
In those few bodies, indeed, that are denser in the
liquid than the solid state (water, antimony, &c.)
there must be a diminution of this force after the
particles have approached within its maximum ; since
the particles of ice have it strongly, while in water,
although nearer, they have it not.
No degree of strength in the radial forces, or attrac-
tions and repulsions, could render a body solid, without
tangential force. Indeed the repulsion (and therefore
in all probability the attraction too) is greater in
water than in many of the most perfect solids. It
resists extension probably 50 times more strongly
than deal, and more strongly than wrought-iron; and
although this resistance or attraction extends through
so very small a range (about mth of the dis-
tance of the particles) that a drop of its own sub-
stance hanging less than i of an inch suffices to pull
it through that range and treat: it, there are many
well-known liquids as perfectly fluid as this (treacle
is almost so) which show by the threads of them that
may hang, an attraction extending through so much
longer a range as to equal at its maximum that of
many solids strong enough to be used in construction.
Perfectly solid brick probably could not suspend so
long a column of itself as perfectly fluid glass could;
understanding by perfectly finial as mobile or easily
disturbed as water. Moderately good brick is pulled
asunder by 1501bs. per square inch, or a column of
itself 60 feet deep; and‘ glass as fluid as oil, it not
water, can form threads longer than this. Probably
a pendant of sandstone (like the “miraculous pillar”
in the grotto of Bethlehem) could not hang so far
without breaking, as either thoroughly melted glass
or the spider-web fluid. This latter, indeed, has been
called the “ most ductile of soliels,” but is no more a
solid than melted glass, which it very closely re-
sembles, and is the only fluid we know at common
temperatures approaching it in cohesion.
Still further to show how independent solidity is
of cohesive attraction, we may find a converse to the
above, in perfect solids whose resistance to extension
is not only as weak but as limited as that of treacle,
oil, or perhaps water. Such are the crystals of the
lead-tree and those in which iodine or sulphur de-
posit themselves from their vapour, which may fall
apart by their own weight while smaller than a globule
of mercury that does so. But a perfect solid (as these
probably are) can retain any shape whatever, if small
enough; whereas a perfect fluid can retain no angular
shape, be it ever so small, no deviation from the sphere,
the thread, or other figures of equilibrium, not even
so much roughness as constitutes a dulness of polish.
*STRENGTH' or MATERIALS,-
~ was»-
As bodies are more or less solid, then, simply in
proportion to the tangential force, independently of
the radial ones, we might call the measure of this,
their solidity; but it is universally spoken of as their
lzurdness, although Dr. Young called it rigidity, which
in common parlance has quite a different meaning.
He introduced a useful term, however, to express the
mode of measuring it. To overcome this resistance
simply, without opposing either attraction or repul-
sion is, in his language, to detrude the solid. Thus
joggles in masonry, or treenails in carpentry, driven
through two timbers that are in contact, will answer
their end as long as they are not detruded, and the
rivet of a pair of scissors or pincers can fail only by
detrusion. Now detrusion will affect solids in two
very different ways, according as the tangential force
exceeds or falls short of a certain ratio to the maxi-
mum attraction or breaking stretch. Some may be
detruded to any extent without ceasing to cohere.
Soap is a familiar instance, for, provided We do not
pull it or any part of it directly asunder, a portion
from the middle of a bar may be pushed through be-
tween the remaining parts, cohering to them all the
while with as much attraction per square inch as at
first. l/Ve believe that Indian-rubber may be treated
in the same way, and so might lead, and probably all
decidedly malleable forms of metal. But where this
cannot be done, we know no instance of detrusion
proceeding to a certain space, like extensibility,
and then at the limit producing fracture. Inorganic
bodies that may be broken by detrusion (as brick,
stone, &c.) seem to be instantly broken by any
detrusion however small. As far as we know, then,
solids either cannot be detruded without fracture, or
can be detruded to any extent without it ;_ and this
divides them into two grand classes, those which can
be crushed, and those which can be squeezed or flat‘—
tened out, for both these operations reduce themselves
to the detrusion of particles, one with fracture and
the other without it. Very composite structures,
such as wood, may admit, in certain directions, of
flattening to a definite limit, and then crushing, ac-
cording as the cohesion of different orders of grains
or members are called into play; but every uniform
solid, glassy, crystallic, crystalline, or granular (with
or without subgranulation), even fibrous or laminar (if
examined in a definite direction), i. e. every mineral
body, must belong to one or other of these two classes;
although we may be ignorant to which to refer some
of the commonest materials from their great strength.
Cast-iron and cast-copper and zinc may all be crushed;
but brass, the compound of the two latter, it seems,
cannot, for a cube of it has been- squeezed into half its
thickness.
Properly speaking, all that cannot be crushed are
imperfect solids, so that malleability is the first step
of a scale leading to fluidity. Whatever cannot be
crushed, can only be broken in one way, by pulling
asunder; while perfect solids can be broken in two
ways, by tension or by detrusion. It is usual to de—
signate four modes of fracture, and four kinds of
strength, and also of elasticity, viz. those of tension,

of compression, of ,flenure, (or cross-strain,) and of
torsion; and doubtless it is.‘ useful to have tables of
the resistances of given sizes of different solids, and
rules for calculating those of other sizes, both to
pulling asunder, crushing, (if capable of it,) snapping
across, and twisting of; as well as to given degrees of
disturbance by each of these applications of force;
and the amount of disturbance by each that will be
restored by their elasticity, or will just begin to
cause a new arrangement of particles, or permanent
change of form, which is called a set. But although
this has been done, as we shall show, to some extent,
for all four cases, we must impress on the reader that
all of them except the tensile trial are only measures
of complex effects, very uncertain on account of that
complexity; and that all the fractures by pressure,
flexure or torsion, are reducible to combinations of
the two only simple cases of fracture, by tension and
detrusion, and would be far better calculable if the
laws of these two alone had been investigated with a
small portion of the labour and expense that has been
devoted to these experiments. Thus, when a beam is
broken across, whatever be its material, it ,is first
somewhat bent. The particles on the convex side are
stretched further apart, and those on the concave side
brought closer; until, in most cases, the former pass
beyond their attractive distance and separate at the
point most stretched, (that is, most curved,) and the
fracture is really one by tension. In some very in.
compressible bodies, however, whose repulsion ex-
ceeds the tangential or sliding force, as cast-iron, and
probably some stones, the failure begins on the con-l
cave side by a wedge flying out, to give room for the
approach of the parts on each side of it, and thus the
fracture is one of detrusion. Again, an axle or any
similar body is twisted off, if granular, by simple
detrusion at the smallest or weakest section, the outer
grains of course sliding first, and it has been reckoned
that the force required is- just two-thirds of what
would detrude the same cylinder straight across; but
if fibrous, it yields by the outer fibres being twisted
round the inner, like a rope,,and so extended in length
till they are pulled apart by simple tension. rl‘he case
of fracture by compression, as in columns, is far the
most complex and uncertain effect of the four that
have been experimented on. In all columns of the
Doric proportions, that is, from the smallest length
up to six times their diameter, (for the delicate per-
ception of natural effects by the Greek architects, led
them to distinguish the limits to this class of columns
as exactly as the latest experiments of our engineers
have done, or even seem capable of doing) the frac-
ture is one of detrusion along a plane or planes, whose
inclination to the line of pressure are always the same
in any given material, evidently depending on the
ratio between its repulsive and sliding force, just as
the inclination down which a body will slide along a
plane depends on the ratio between its weight and
friction. In Doric columns, this takes place with less
force than can bend them, so that poets have been
strictly literal in calling them unbending. In all
longer or slenderer ones, there is a certain force that,‘
760
STRENGTH OF MATERIALS.
with the ordinary exactness attainable in equalizing
the pressure over their ends, may, by approaching one
side of the column, run a risk of pressing that side
into a'coneave figure, and making the opposite one
bulge. This pressure of course must never be
reached. It limits the practical strength ‘of the
column, although it may be perhaps greatly exceeded
without breaking it, which then happens exactly as
in the snapping across of the beam, by either a
tension-fracture on the convex side, or detrusicn-frac-
true on the concave, according to the nature of the
material.
The resistances also to a given disturbance of
figure by each kind of strain, or what are called the
stifness in tension, in flexure, &c., all spring simply
from the elasticity; which, in its scientific and only
exact sense, means precisely the same in solids as in
liquids or gases, and applies only to the radial forces,
i.e. the resistances to extension and compression, and
not to the tangential force or resistance to detrusion,
for we have no proof of such a thing as any detru—
sive elasticity, or return of particles once detruded.
Such a property has been supposed indeed by some
reasoners on the undulatory nature of light, to be re—
quired, not in solids, but (what is far more incon-
ceivable) in the rarest and most mobile of fluids, that
which propagates the waves of light. For as it is
proved that the vibrations constituting light are per-
formed in a direction across that in which it proceeds,
while the analogy of sound led to the gratuitous suppo—
sit-ion that the particles of ether moved out of their
places to and fro, like those of air, or cars in a corn-
field, and acted each upon its neighbour like the suc-
cessive parts of a string along which waves are tra-
velling, and this in every direction alike; this might
well lead Sir J. Herschel to say that the so-called
fluicl required to be imagined with properties charac-
teristic of solids, or rather to be more solid than any
solid; and yet, if it could be conceived, would by
no means get over the difficulty; for what becomes of
the vastly stronger waves that any fluid capable of
this, must still more certainly propagate by its common
radial elasticity, ie. by compressions and extensions,
like the waves of sound, in the same— direction that
the particles are displaced? Now, by the mode in
which the writer has always imagined these vibra-
tions, namely, by leaving the particles in their places,
and supposing them to be merely set oscillatiny or
lilratiny like the moon, on an axis of their own, and
to have any shape but spheres, their repulsions would
tend to keep them all in parallel positions, like the
atoms of a crystal, or like so many little magnets, and
a disturbance of one would be propagated to others
all round‘ to infinity, in precisely the way required to
account for the vibration always transverse to the
progress, and to lead to every one of the phenomena
of polarization, and the laws of Fresnel’s theory,
without the least difiiculty or deviation from our most
common conceptions of fluidity, and without calling
into play even the ordinary elasticity of compression,
for the distance of ethereal particles would be no-
where altered. We' mention this because it might be

said, that such an inconceivable kind of transverse
elasticity as is commonly attributed to this fluid, is
likely to be still more a property of solids; whereas
we see no reason for supposing it in either one or the
other.
The elasticity of solids, then, is simply like that
of all matter, the rate at which both the attrac-
tion and repulsion (between which the particles rest)
6cyin to increase, in their displacement either way
from the neutral distance. It is one specific quantity
for each body in a given state of density, for it cannot
be different with regard to compression and to exten-
sion, because a natural law cannot be supposed to
change per saltum, or the Boscovician curve (Fig.
2085) to make an angle just where it crosses the axis
at A, B, or 0. Its inclination thereto at the point of
crossing is the measure of the body’s elasticity, at
this particular density. That the inclination rapidly
alters above or below this, only affects its elasticity
in other states, rarer or denser, which may vary
according to some complex law expressed by the
curve; but its elasticity in one given state simply
depends on the curve’s tangent at one point.
Dr. Young invented the excellent mode of express-
ing this by the moclulus of’ elasticiti, that is, the
height to which a body would have to be piled in
order that any small addition to its top, of its own
substance, might compress the rest by a quantity
equal to its own bulk. The advantage of this mode
is, that we measure the elasticity by only one kind of
unit, feet, or miles, and one number, the lieiylit. By
any other way we must introduce three arbitrary
quantities. Thus we may say that wrought-iron is
extended or shortened 10500th of its length by every
added tension or pressure of a ton per square inch.
This is an instance easily remembered; but no other
substance would have the same simplicity of numbers,
if measured the same way, and the inch and ton are
both arbitrary and artificial. To express this in Dr.
Young’s way, we find what height of this substance
would be compressed the ,ogooth by an addition as
long and broad as itself, and ,,,},,,,th as high. Now,
a column of water 34h feet high presses 15 lbs. per
inch, like the atmosphere. To press a ton per inch,
it must then be 5,075 feet high; but iron, being 7%;
times as heavy, need only be 077 feet. This com-
presses any iron below it 103,00, and therefore, the
iron below must, to be compressed 6.77 feet, be 10,000
times 6'7 7, or 6,770,000 feet deep, or 1280 miles,
which is its modulus of’ elasticity.
The modulus of elasticity of air, at the common
density, will thus be found by considering what
height of it would press with a given small pressure,
say of 1 lb. per inch, which we know compresses that
below it 1-115, and thus a column of 15 times that
height would be compressed the length of the com-
pressing column. The modulus is about 5~§ miles, and
that of any other gas, at the common pressure, will
be more or less, inversely as its density, so that, at
equal densities their moduli seem to be alike.
It is very strange that the moduli of all liquids,
even so different as mercury, water, and alcohol,




srannern or MATERIALS.‘
’- 761'
seem, as far as they are known, egaal, viz. about
7 5,000 feet, or 14 miles.1 This depth of each, or,
indeed, the depth of the modulus ~of any substance,
would compress its bottom into twice the density of its
top, provided the elasticity remained equal through»
out, or at all these densities; but such is certainly not
the case with gases, nor probably with any bodies.
The modulus of elasticity is necessary to be known
before we can frame trusses of any material so as to
retain a desired form exactly, and not to bend in any
of their parts. By a truss we mean any arrangement
of bars to support some weight by their direct or
lengthway strengths only; that is, by compression
and tension, without any liability to flexure; and this
is the only scientific or really economical mode of
combining any fibrous material (alone or with granu-
lar ones), to uphold roots or bridges, and the only
mode regarded as legitimate or rational in most mo—
dern countries. [See Oxnrnnrnn] Now, if a truss
(as Fig. 2086) were merely drawn, full size, and then


F -
Fig. 2086.
the pieces formed exactly as in the drawing, the
erected truss would not have the form of the draw-
ing; for every piece that acts by resisting compres-
sion, as a, A, B, and B, would be s/zortenerl ere the
repulsion could be elicited by which it acts; and
every piece tying others, or resisting extension, as o
and D, would be stretched a little ere its particles came
to the distance where their attraction yields the requi-
site resistance. Thus the form would droop towards
that of Fig. 2087. To ensure the intended form, each


/ l
t
F ig. 2087.
tensile piece or tie must be made originally starter, and
each compressed piece or stretcher originally longer,
than they are intended to become anu are drawn in
the design; and to find the difl‘erences of the lengths
drawn and those made, we must reckon the pounds
pressure or tension borne by each, thence how long
its own scantling would have to be extended to weigh
that number of pounds, and this length will be a
second proportional to the modulus of elasticity, the
third being the actual designed length of the piece,
and the fourth the correction or difl'erence required.
The modulus of elasticity also measures the still.’_
ness of flexure (which is all that we commonly under-
stand by stiffness), and observations of this have been

(1) In all the works which we have seen, this is called 750,000,
after a misprint in Dr.Young’s original Lectures.

used as the easiest means of ‘determining that modu-
lus. In bending a how, it is merely the attractions of
the particles next the convex side, and repulsions of
those next the concave, that constitute the active or
measurable resistance. The hardness or passive re-
sistance to detruding force is indeed necessary to
confer the ability thus to oppose and recover from
bending. Without it the bow would be fluid; but
yet it does not, as long as it remains unconquered, at
all affect the stillness, which depends solely on the
elasticity common to solids and fluids, that of attrac-
tion and repulsion. When, indeed, the body takes
any set, or does not wholly recover, but permanently
keeps a new form, it is this tangential force, or lzarrl-
ness, that has yielded somewhere, by allowing a sliding
of some particles into new places. It is then as stiff
in the new form as the old, and will admit as much
deviation therefrom before taking another set. Thus
the elastic flexibility is measured, not by the extent
to which it may be bent, but through which it will
return, however far bent; and this is a constant mea- -
sure in any one substance, definable by the number of
times a straight bow’s thickness is contained in the
shortest radius of curvature it may assume at any
point, and recover its straightncss. So also of sim-
ple tension. The elastic ea'tensibilit'z/ is the fraction
of its length that it will return through, however far
extended. Again, the elastic toi'sioility may be defined
by the fraction of a cylinder’s length, that its diameter
will be, when it- is just capable of returning one revolu-
tion, however many times twisted. Lastly, the elastic
compressive limit (which is not, like the three former,
of much use to know) is the fraction of a body’s
depth that it may be squeezed through, and recover.
All these four numbers or fractions are constant for
any one solid, whether they are limited by setting (as
in lead), or by fracture (as in stone) ; and it might be
supposed at first that being measures of the same
thing in difl‘erent ways, (viz. the relation between the
elasticity and hardness,) they would all be deducible
from one another, or bear a constant proportion; but,
in fact, they are not measures of the same thing,
except perhaps the extensibility and torsibility, and,
in- one rare case, the flexibility. To understand
this, we have only to remember that the modu-
lus of elasticity is not constant for any body, but
varies with every change in the distance of the parti-
cles, and so does probably the hardness, or tangential
resistance. But, of the above four numbers, none
depends on the common modulus or common hard-
ness, those at the neutral distance of the particles,
but at some strained distance. In the cases of simple
tension (when limited by setting) and of torsion, this
distance is merely the greatest they can be strained to
without overcoming the hardness, so that between
these we may expect a constant relation. In tension
limited by fracture, the hardness is not concerned at
all; for the extensibility, when it is a lrealciia/ exten-
sibility, applies to liquids, we have seen, just as well
as to solids, being simply the measure of how far the
neutral distance of particles is exceeded by the distance
where the next attraction is a maximum, or, in fact,
762'
STRENGTH OF MATERIALS.
what ratio e c, for instance, in the curve, Fig. 208 5, bears
to c z. In the case of compression, the limit, whether
by crushing or flattening, evidently depends on quite
another modulus of elasticity and another hardness,
those at the nearest distance the particles can reach
without detrusion. Lastly, in the case of flexure, the
limit may be either by setting, by tensile fracture on
the convex side, or by detrusion of a wedge from the
concave side. Setting, however, as well as fracture,
will begin on that side whose particles first reach the
limit at which the hardness yields, and allows them
to slide. It might be thought, then, that whichever
is smallest, the limiting eatensioilitg or cornpressitilitg,
the flexibility will be deducible from, and bear a
constant relation to, the lesser of them. It would be
so if the approximation and separation of the particles
most acted on, those in the convex and concave sur-
faces, were equal; but this can occur only on the sup-
position that their attraction and repulsion vary exactly
as fast and by the same law in proceeding each way
_ from the neutral distance; which amounts to sup-
posing the Boscovician curve to bend opposite ways
like an f in leaving its axis, and this with exactly
similar curvatures on each side as far as the point
reached at the yielding; i.e. supposing the modulus
of elasticity within these limits (represented by the
inclination of any point of the curve) to be a maxi-
mum at the neutral distance, and diminish lot/i ways
therefrom, alike and equally; whereas it is far more
likely in all cases to increase one way and diminish
the other; that is, the curve to bend the same way
before and after crossing the axis. Now, owing to
this, that the aggregate of all the attractions in a bent
body may balance that of all the repulsions, the num-
bers of particles attracting and repelling cannot be
equal; nor are the forces of the most strained ones of
each kind necessarilg so. At the beginning of flexure,
indeed, both must be equal, because any indefinitely
short piece of the Boscovician curve is virtually
straight (as of any curve), and so the modulus is then
equal for all the particles, and, to effect the balance,
there must be an equal number of them attracting
and repelling, and the neutral plane (or that in which
particles retain their neutral distance) must pass
through the centre of gravity of the body’s section.
Hence the stiffness .in fie/care (not the strength or
Zrrea/cing flexure) bears a fixed relation to the com-
mon modulus of elasticity, as long as the flexure
is very small. The same relation will extend to any
flexure, and even to the limits or breaking strengt/is
by tension and flexure, only in the rare or perhaps
impossible case above supposed. In all other cases,
the different variations of the elasticity in remov-
ing particles further, or bringing them nearer, that
is, the dissimilarity of Boscovich’s curve on each
side of the neutral distance 6, will cause that the
further the bow is bent, the more unequal become
the number of the particles compressed and extended,
in order that their aggregate attractions and repul-
sions may be equal; and thus the neutral plane moves
away further and further from the centre of the sec-
tion, till, at fracture, it has a certain definite position,

depending on the nature of the solid as well as the
form of section. In most woods, formed into a rect-
angular beam, it is about three-eighths of their depth
from the convex side. as may be seen by the appear-
ance of the broken surfaces. In cast~iron, on the con-
trary, it has been found to move the opposite way until
it is 4! times nearer the concave than the convex side.
In bodies whose flexure is limited by fracture on
the convex side, this limit will plainly, like that of
extensibility, be independent of the hardness, since
no detrusion happens. It will depend only on the
elasticity common to fluids and solids : but not on any
one modulus thereof, but on the whole series of them,
that is, the whole figure of the Boscovician curve
from the attractive maximum 0 which has to be over-
come, down to a point about as far on the other side
of 0. TVs say about as far, not exactly as far, because
the repulsion of the particles brought nearest need
not equal the attraction of those that yield, for it is
the aggregate forces of all the attracting and all the
repelling ones that are equal, not the greatest of each.
It must further be remembered, that although the
limits above defined, or extreme extensibility, flexi-
bility, &c., are useful data, we cannot from these and
the common modulus of elasticity deduce the strength,
i. e. the forces producing those extreme extensions,
flexures, &c. ; for these depend not on the common
modulus, but on the new one, belonging to the par—
ticles strained to the utmost; or, in the case of
‘flexure, on all the moduli for them in every inter-
mediate state.
Next to the form of that part of the Boscovician
curve above described, the most useful determination
- would be the law by which the sliding resistance or
hardness varies with the distance to which the sliding
particles are pulled apart or pressed; or, What is
equivalent to this, the force that will produce detru-
sion when acting in all directions inclined to the
detruded surface. This might be expressed by a
curve like 13 n r, Fig. 2088, in which A B is the moda-


E a Fig. 2088.
lns of tenacitg, or depth of a parallel-sided pendent
just heavy enough to pull itself asunder at the top.
A0 A0’, &c., the lengths representing, on the same scale,
the forces necessary in those directions to pull asun-
der the same area that is pulled asunder by AB
directly. A D, the morlnlns of cletrasion, representing,
on the same scale, the force to detrude this same area
without opposing the elasticity either of attraction or
STRENGTH OF MATERIALS. 7 6?;
repulsion. This was thought by Dr. Young, from at which it will, if strong enough,‘ produce sponta-
a few experiments, to be generally about twice AB neous detrusion as in the crushing of columns; which
(as if the curve were a parabola with its focus at A). angle, according to Hodgkinson’s experiments, is 35°
Dr. Robison also made a few experiments on pins of in cast—iron. r A, the modulus of ems/ling, or height
weak materials passed through holes in three iron to which a perpendicular precipice of the substance
bars and detruded, and found the detruding force to must be piled in order to crush its own base, which
exceed the tenacity, in a soft sandstone, as 57 5 to it will do so as to slide off and leave a bank whose
205, and in softer bodies to be from once and a third inclination to the vertical is FA 1). This curve, giving
to double of it. Again, A6 A6’, 850., would be the the law of hardness, as Boscovich’s does that of elas~
forces necessary to produce the same efiect in these ticity, the two would embody, as far as we know, all
directions, where a portion of them goes to press the the specific mechanical distinctions of one simple solid
solid together and (if the force of hardness be analo- from another, all the peculiarities of its consistence,
gous to friction) to increase the resistance to detru- and enable all its behaviour under strains to be
sion. F a 1), the inclination to any compressing force, deduced. The hardness curve,however, is not merely

TABLE I.--STBENGTHS INDEPENDENT or HARDNESS.



S )chfii‘, Modulus of Modulus of Weigh he * 1 ' .
Gl'avzly. substance‘ Elasticity. Tenacity. for l inrdliif ' Lmogtirgzllikmg
feet, inch. grains.
‘0012 Air 28,000 unknown if any. 1-0000 Water 75,000 Y. 0'22 554,L G.L. - ‘00000006 +
13'6 Mercury 75,100 Y. 0'13 590 G.M. ‘00000006 :1:
feet. lbs.
1' + Juice of White Bryony Berr2es............... unvecofdedt 2 ‘t’ - 13' + Rob.
1'29 Plaster of Paris unknown. 120 67 Mo-
1'6 to 2 Brick, pale red 300 i 230 G-M-
2'706 White Marble 2,150,090 T- 464 551 H- 1100717 T.
11'353 Cast Lead 146,000 T. 370 1.327 Re- unrecorded.
11'3 + Lead Wire 495 :1: 2,464 G.M. 1075 Bath Oolite.......-
540 478 T. 11-407 Milled Sheet Lead 670 3.360 T-
2'362 Craigleith Sandstone 753 772 T. 2-113 Portland 1.672.600 T- 935 857 '1‘. ‘000558 T.
Cast Tin “Hm-""-......nun...“nu-"nu"...l T-
R’e- "-
7‘3 + Tin , 2,120 6,700 Re. 7028 Cast Zinc 4,480,000 T. L376 + 5,700 + T- ‘000416 +
2621 Dundee Sandstone 2.330 2,661 T-
19 238 Cast Gold ... 2,900 + 20,160 G.M. ...
21‘ + Platinum Wire 4,200 33,000 G M 7'1 :1: Cast Iron, Scotch and Welsh, 1:842 ....... .. 5,750,000 T- 4,309 13,440 H-
19-5 + Gold Wire 4.400 315300 G-M 8'396 Fine Brass (Copper 2, Zinc 1) 2,460,000 '1‘. 4,931 13,000 Re- ‘00075 T. t
8788 Cast Copper 5,000 19,000 Re , '987 Hempen Rope, not cable-laid 5,230 2,400 ~ 7'113 Cast Iron, cast horizontally, 181.6 ....... .. .,.. 6,043 13,656 Re-
7'074 -————- , cast vertically, 1'816 ....... .. 6,347 19,448 Re. 2'752 W'estmoreland Sla 12,900,000 T. 6,140 7,870 T. ‘000611 T.
1'66 :1: Ox Bone 6,600 4,923 Mo-
2'5 :l; Plate 7,200 3.960 M0. 2'75 Scotch S’late 15,790,000 T. 7,400 9,600 T. ‘0006 T.
ll "091 Silver, cast or wrought 3,200 33,000 G M 8'879 Wrought Copper ................................ .. 3,709 33,700 Re. 2'75 ‘Welsh Slate 13,240,000 '1‘. 9,100 11,500 T. ‘00073 '1‘.
1'3 Whalebone 1,458,000 T. 10,000 i 5,000 T. ‘0068 '1‘.
tons
7'5 to Iron Sheet, cut lengthwise .._. 9,296 14 Mi. 7'7 1 -——~-—--, cut crosswise 11,950 13 Mi. 8'153 Gun-Bronze (Copper 4, Tin 1) hard 2,790,000 T. 11,914 16 Re. ‘03-104 T.
8'8 + Copper, Sheet 12,400 21 K-
8 9 :1: Copper Wire 15.000 27%,- K. 7,6 Iron Bar, English 7,750,000 T. 16,600 25 L. '12 T1.
to -———-—-, Russian 18,000 27 L. . .
7.8 -—~———-, best Swedish '25
— Wires, T15 inch diameter 26,560 40 T1. Steel, Damascus 20.000 :1: 31 Mi. - .
-——— , do. twice refined........................ 29,000 i 44 Mi. .
7'8 —— , English raw 33,000 :1: 50 Mi. .
to ——————— shear 37,000 57 Re. .
7'9 —-—-——-— blistered and h'ammered... 39,000 591,. Re. . .
cast 29,000 44' Re- - -
—————~———— cast and tilted 8,530,000 T 39.800 i 60 Re. .
'6 :1: Mahogany, Honduras 6,570,000 T 30-000 :l: 311: B-
'75 to 9 + Oak, European 4,730,000 T 30,000 I 4 to 5 B.
'65 Pear-tree............................................. 35,800 :t: 4i: B.
'7 Beech 4,600,000 T 36,300 5 i B-
7'8 Iron Wire, 51-5 to ,1, inch diameter 39,840 60 L.
'9 40,000 7 B.
'56 Red 01‘ Yellow Deal ............................ .. 8,333,000 T. 46.200 5 :t: B.
'9 + BOX 51,400 9 :l: B.
'51} Elm 5,680,000 T. 55,000 6 B.
'5 + Larch 4,415,000 T. 50.000 6 B.
'7 i Ash 4,970,000 T. 58,530 8 B.
'5 :1: White 8,970,000 T. 59,000 0 B.
1-1 + Paper glued together in strips 60,000 i 13 M0.
7-3 Iron Wire. 151-6 inch diameter, best ........ .. 60.000 :1: 90 + L.
'46 American Pine 8,700,0C0 T. 63.000 6 B.
1' + Hemp Fibres glued together .. . 100.000 + 41 Mo.
An'rnonr'rnzs.—-'B. Barlow. G.L. Gay Lussac. G.M. Guyton Morveau. H. Hodgkinson K. Kingston.
L. Lamé. Mi. Mitts. Mo. Moseley. Re. Rennie. R0. Robison. T. Tredgold. T1. Telford. Y. Young.


761;
STRENGTH OF MATERIALS.
definite in form, but also in size. We may conceive
two bodies as different as jelly and iron with the same
form of» this curve, but the modulus AB would pro-
bably be an inch in some kinds of jelly, and exceeds
a mil‘e‘in all kinds of iron.
- The- measures called nzoduti, which are definite
lengths, heights, &c., of the solid’s own substance,
and not weights, far more truly express and give us
truer ideas of the relative strengths or constructive
values of diii'erent solids, than the common tabular
zoeig/rts' do, while they are quite as applicable in cal-
culation. Solids are mechanicallyvaluable inproportion
to the-boldness of scale and lightness of proportions,
that structures of them may receive; that is, to the
scale‘ on which they may embody any given form
(such as fluids could not embody at all) and retain
that form in spite of their own weight. Now this
is proportional, not to the common tabular strengths,
but to- the moduli. Thus the former are greater for
metal'sthan for woods, but the moduli are greater for
Wood's. than metals, and this latter gives the true
relative boldness attainable in these two classes of
material,—as a comparison of existing wood and iron
bridges, roofs, 8:0. shows.
Table 1. contains some of the most trustworthy
measures that have been made of these elements:
the chief rules for applying them will afterwards be
given-
The'bodies are arranged in the order of their real
tenacity, i.e. the tenacities of equal weig/zts, and it will
be seen‘ that been]; immensely excels in this property
all others that have been measured; for we have no
measurement of the bamboo stem, nor of hair, and
many vegetable fibres that may excel hemp. Next to
it come the strongest of three widely differing classes,
common woods, pasteboard, and the very best fine
iron wire, and these in their most tenacious forms
seemi equal. Vegetable bodies would be incomparably
superior to alll mineral ones, but for the singular pro-
perty of the best steel and iron wire, which seem a sort
of artificial organisms by which we can just approach
and rival the most tenacious of common woods. If a
shaft. existed 10 miles deep, no substance in the table
but the last four would be available for letting down ,
to thebottom'. All the rest would break by their own
weight, and were it 12 miles deep, only hemp, of all
bodies yet measured, would serve.
The stifest matter yet examined, will be seen, by
the modulus of elasticity, to be slate, and tho stifl’est
kind,‘ Scotch slate, a primary rock. Were the earth’s
interior formed of any other substances yet measured,
it may be reckoned that the compression would so
condense them towards the centre, as to make the
mean’ density far exceed 5, the greatest that is recon-
cileable with astronomical phenomena; but the least
compressible rocks are evidently placed lowest, and if
this Scotch slate extended to the earth’s centre, it
- would‘ not acquire even the density that we know to
exist there.
The columns relating to absolute tenacity are of
little practical use, (though this is what most experi-
menters have chiefly observed,) for no material can

safely be strained in construction to the point of‘
gaining any permanent extension: but the modulus
of elasticity enables us to reckon the extension, com-
pression, (in length,) or deflection of any body by a
given force, so long as it suffers no set or permanent
change.
To find the extension or compression lengthwise,
the square of the body’s Zengt/z in feet must be mul-
tiplied by the straining force ; and then its weig/it (in
the same denomination as that force) by the modulus
of elasticity; and the former product divided by the
latter will give the alteration of length in feet (or
decimals of a foot). No dimension but the length
need be known.
The compression thus found for pillars, struts, &c.,
is of course independent of any shortening by tend-
ing, which (as will presently be seen) cannot, in legi~
timate construction, be possible by any Zengt/iway
pressure whatever. The deflexion, however, of long
bodies by a cross-strain has nearly as much need to
be found, in wooden construction, as the compressions
and extensions by lengthway strains. It has no appti~
cation at all to any other material than wood, because
no honest constructor would require other materials
in lengthy pieces, (into which they must purposely be
made,) to bear a pressure on one side opposed only at
distant points on the other side; such being the pre-
cise kind of form and mode of treatment which we
learn, from the earliestexperience, to choose for bodies
which are intended to be broken, and hence are made
not inconveniently strong. Barley-sugar, for example,
is made into sticks, and not retailed in blocks or loaves.
1 In speaking of beams, however, we use the term as
excluding ao'o/iitraues. These act dili‘erent] y, and
yield their full strength, for there is in cross-strained
- bodies, as well as pillars, a certain proportion between
bearing length and thickness, within (or shorter
'than) which proportion, they will never break by
fiexure by any load whatever; but the centre part
_will fall through and leave the ends behind, sooner
than bend sufficiently to break. This proportion will
vary with the ratio of the tenacity and hardness to
each other, which has been measured in only one in-
stance—Dr..Robison’s “soft sandstone,” and it gives,
we believe, a limiting ratio of bearing length to depth
very near the greatest existing in ancient architraves,
i. e. in the shallowest Corinthian ones, and certainly
greater than in any Doric or Egyptian. It is only
cross-strained pieces of a longer proportion than this
limit, that we call teams; those shorter are properly
are/zit'raoes, and are true in principle, wasting none
of the strength of the material, although perhaps
they should be regarded as superseded, (except in
stone districts, and on the smallest scale,) by the ad-
mission, for these 1,900 or 2,000 years, of arches or
oblique-pressure construction into all building.
Wooden beams, then, being the only ones which
we need consider, and these being unlikely to be ever
used with any shape of section but rectangular,
the following rules will determine the deflection by
a given load. - By the deflection is understood the
greatest space any part is displaced from its un-
STRENGTH OF MATERIALS;
.765
loaded position, measured by the usual units—feet
or inches. But we must evidently always allow a
greater or less deflection as a timber longer or
shorter; so that a certain fraction of the length of
the beam must in all cases be the quantity allowed,
and it is more useful to get this fraction at once
than the absolute measure in inches or parts of
inches. ‘
For a bracket-like beam, projecting beyond a ful-
crum and loaded at the end, take for a dividend,
two-and-a-quarter times the load multiplied by the
cube of the projection. For the divisor, multiply
together the modulus of elasticity, the weight of the
beam’s projecting part, and the square of its depth
(at the fulcrum). The quotient of the former by the

latter, is the fraction of the beam’s
it will be deflected. - -
In a lalaneeal beam loaded at the, ends, each arm
independently bends by the above-rule).
A spanning beam, resting loosely on its supports
and loaded in the middle, is a balance-beam turned
upside down. Therefore take the upward resistance
of one support, namely, lialf the middle load, and the
above rule will give the fraction of its lialf‘ length.
that the centre is deflected. .
A spanning beam that crosses and is fiaerl to its
supports, as when a long timber lays across several
supports, will evidently be less deflected than if it
were cut through on each support, or even the top
fibres only cut and allowed to separate. The deflec-_
proj ection ‘which
TABLE II.—-Srnnnerns Arrnc'rnn BY HAnnnnss.






tion of a length of this, between two supports will,
it appears to us, be only a quarter as great as if it
were cut from the adjoining lengths.
All these are deducible from the simple principles
of levers, on the supposition of the attraction and
repulsions of the particles remaining equal, and the
neutral plane in the middle of the depth; which is
not perceptibly erroneous, in wood, up to any safe
amount of deflection.
It has also been proved that a weight egaallg ilz's-
tribnterl along a bracket-beam produces tnree-eiglrtlzs
the deflection that it would if collected at the end;
but on a spanning-beam, five-eighths of the deflection
it would cause if collected in the centre.

Weight of Elastic ' Weight of
Qvecific Elastic Modulus this Linear Modulus this
Gravity. Substance- Extensi- of Modulus for om- of Modulus for
bility. the same. 1 sq. inch. pression. the same. l sq. inch.
feet. lbs. feet. lbs. ,
2'5 :1: 461 i 500 R-
2085 Brick, pale red 290 275 621 564 R.
2168 red 858 808 R.
yellow Hammersmith pavers .... .. .. 1,064 1,000 R,
do. burnt.... .. 1,532 1,441 R.
v Stourbridge fire-brick.................. .. - 1,825 1,716 R.
2316 Derby Sandstone .. 3,126 3,142 R. -
2428 Do. another quarry ' .. 4,123 4,344 R.
2428 Portland ‘000558 935 75 T. ‘002 4,000 3,729 R.
2760 Italian Statuary Marble ‘000717 464 551 H. ‘007 5,058 6,058 B.
2-452 Craigleith Sandstone, against the strata... 5,156 5,488 R.
2507 York Magnesian Limestone, either way... .. 5,251 5,712 R.
2662 Cornish Granite...'................................ ,.. 5,502 6,360 R-
2506 Bramly Fall Sandstone, Leeds .. 5,571 6,058 R.
2'53 Dundee Sandstone 2 80 2,661 T . 6,038 6,630 R.
2-452 Craigleith, with the strata 753 772 T 6,498 6,916 R.
Devonshire red marble .. 6,623 5,828 R. .
Peterhead Granite 7,386 8,280 R. _ 1'
2593 Black Limerick Limestone or Marble .... .. 7,607 8,855 R. =
2-697 Black Brabant do. 7,876 9,200 R.
2-599 Purbeck shelly do. 8,120 9,160 R.
2726 Italian veined White Marble.................. 8,183 9,682 R‘.
2625 Aberdeen Grey Granite . 9,581 10,912 R.
2871 Red Porphyry 28,455 35,568 T.
8879 Wrought Copper 26,737 103,000 R
878%; Cast Copper .. . . 30,689 117,000 R
Cast Iron, horizontally cast 52,422 R. to}
——-———vert1cally cast 58,040 R. R. and H
'7 Beech ‘00175 7,500 2,360 B. ‘56 Larch .. ‘0019 8,500 2,065 B 21,000 4,920
'76 Ash ‘0022 10,500 3,540 B 75 to '9 Oak, 0023 11,000 3,960 T 11,100 :1: 4,000 R.
~54 Elm 0024 13,700 3,240 B 5,040 1,200 R.
'56 Mahogany, Honduras .. 0024 15,600 3,800 T 2557 Red or Yellow Fir 0021 17,500 4,290 T ... ~47 White do. 0021 17,600 3,630 T ... 7,680. 2,000 R. _
'46 American Pine 0024 20,900 3,900 T '
B. Barlow. H. Hodgkinson. R. Rennie. T. Tredgold.

All the columns in TABLE II. are practically useful,
although the first three, in the case of all bodies
without perceptible ductility, (i.e. all non-metallic
minerals) repeat the numbers of the former table,
because these bodies sufl'er by extension no per-
manent change till they are pulled asunder. The
application of the third column to find the smallest
scantlings for ties, king-posts, and other tensile pieces
is obvious. The tension they are to sufl'er, being
divided by the weights in this column, gives the area
in square inches that would be permanently stretched
by that tension. Perhaps tie-ice this area may be
considered enough to give to rlnetile ties, as wood and
wrought metal; but at least four times the area must
766
STRENGTH OF MATERIALS.
be insisted on when it is not a stretching but a tree/e-
ing area that is thus found, viz. in all the bodies
Without sensible ductility.
The application of the last column to the sizing of
struts, columns, collar-beams and all other pieces
acting by lengthway repulsion alone, is equally
obvious. The pressure they are to suiier, divided by
the weights in that column, gives the area in square
inches that would just be either permanently shortened
or crushed, and twice this area in the former case, or
four times in the latter, may be regarded. as the
smallest allowable. But this of course disregards all
risk of lending. Now this, we have seen, can only
occur in pillars exceeding a certain proportionate
length, which in cast-iron has been found by Professor
Hodgkinson to be sic; times the middle thickness (or
the Doric proportion), and in substances with a smaller
flexibility in relation to their hardness, as stones,
would probably be found greater and near the limiting
proportion of Corinthian columns, viz. eleven times
the middle diameter. Accordingly there will be
waste whenever lengthway compressed bodies are left
unstayed laterally for a greater interval than 10 or
11 times the thickness in the direction of the stays.
This was universally attended to in all real architec-
ture, with the exception of a few pillars contrived as
feats, between A. D. 1200 and 1250,—for showing
how slender they could be made. Afterwards it
regulated all the Gothic mullion and transom work,
as it had previously done the classic orders. Even
now, workmen left to themselves will not transgress
this rule in carpentry. A principal rafter is a length—
waywcompressed member, but for other reasons is
best .made much more deep than wide. We accord-
ingly stay it laterally by the battens or horizontal
rafters, at intervals notj'exceeding 10 times its width,
and in the other direction by struts from below, at
intervals by no means 10 times its dept/i. At least
they ought not to approach that distance. In other
materials than wood, there is no motive for either
carrying such compressile columns in one length
across several points of attachment, nor for making
them parallel-sided. It is only the middle thickness,
halfway between two attachments, that need bear a
certain ratio to their distance. If therefore this
distance exceed 11 or 12 times the diameter of a
cylinder large enough to satisfy the conditions about
crushing, the strut or pillar must be enlarged at the
centre beyond that diameter, (which is still sufficient
at the ends,) but it is not necessary for this to add
any material, because the centre may be either tubular
"or reduced externally, by A or more longitudinal re-
cesses, to a cross or star section of no greater area
than the ends.
While plain cylindric pillars no longer than the
Doric proportion (in iron, but probably the Corinthian
in stone) are found to have their strength simply
"dependent on area of plan, and no weaker when 6
that when 2 diameters high, thus showing the icliole
' of their resistance to be active till crushed; any that
are longer than the classic proportions (and not con-
trived as above) exert so little thereof that, by the
_/
best experiments, an increase of the excess in length
as the arithmetical progression 1, 2, 3, 4', &c. seems
to diminish the load that may be borne without
flexure, in geometrical progression, to a half, a fourth,
an eighth, a sixteenth, &c. of the absolute strength,
or that of the same column stayed at proper intervals.
Hence may be formed an idea of the enormous waste
of material in columns and all compressed members
when such as to be limited in quantity of matter ‘by
risk of fle'zcnre, i.e. when such are used as may bend
at all with any load; and hence the danger of the
system introduced by some iron engineers, of reduc-
ing, when the material is stronger, the size of supports
instead of the number.
For the strength against cross-strain, which, we
have seen, cannot be deduced (like the stifi'ness against
it) from the above measure of direct strains, we can
do no better than use the measures made of this as
an independent element. These are embodied in the
following table of the weights breaking when collected
on its end, a bracket or arm one inch broad and deep
and projecting a foot.
TABLE IIL—Tnansvnnsn Srnnnern.
lbs. to break a bracket


Name of Wood‘ 1 inch square and 1 foot long.
Acacia 155 E.
Ash, young tree 220 T.
—, old 160 B.; 157 E.
Beech............... 129 13.; 169 E.
Birch .. 129 E.
Cedar of Lebanon 103 T.
Chestnut, edible .. 112 E.
Deal, White, Norway 171 T.
, American ........... .. 143 T.
—, British.................. 116 E.
Fir, Yellow, Norway...... 193 T.
, Memel and Riga .... .. 135 T.
, British 80 T-
158 T.‘
Lombardy Poplar 81 E.
Mahogany, Honduras 159 T.
, Spanish 106 T.
Oak, English, young tree............ 241 T.; 140 B. ; 170 E.
-——-———,.old tree 109 T.
-—-, Canadian 144 B.
-——Dantzig and Adriatic 120 B.
Pitch Pine 136 B.
Plane 150 E.
Red Pine .. 112 B.
Scotch Fir, British..................... 145 T.; 98 E.
Teak 179 to 205 B.
Walnut 122 E.
Willow .. . . 91 T.
Autlzorities.—E. Ebbels: T. Tredgold. B. Barlow.
In applying this table it is‘only necessary to re-
member that the strength of rectangular beams is
affected inversely by the length, directly by the
breadth, and doubly by the depth. Therefore multi-
ply the area in square inches by the depth (or the
breadth by the depth twice), and this by the tabular
number, and divide by the length in feet, to obtain the
lbs. a bracket-beam will break with at its end. Dis-
tributed along its length, it will bear twice this load.
A spanning-beam, with the ends loose, bears, whe-
ther in its centre or distributed along it, twice what
either half of it would hear as a bracket-beam with
the weight’ on its end, or distributed along it; or as
much as one quarter of its length projecting bracket—
wlse. > - -
STRENGTH OF MATERIALS4STRING-OOURSE—-STRONTIUM.
A spanning-beamfia'erl at the ends, so as to bend
there as much as in the centre, (with 3 curvatures
like awave) bears 3-fifths more; so that a long bar,
having many supports, will lose 3—eighths of strength
if the top fibres be out where it crosses them.
To find the load a spanning beam will bear at any
other point than the centre, call it P and the beam’s
ends AB. The load varies inversely as r A. X PB ; so
that the load at any point r, is to that at c, as
on. x cnis tora X Pix.
Owing to the strength varying, (with an equal
length and load) as the width and square of the depth,
while the deflection varies as the width and cahe of
the depth, the strongest beam that can be out out of
a given cylinder or tree is not the stg'fi’est, nor are
either of them the largest.








\ / \ / /
\ // \ \ // / \ \ \lc \\
\ / \ / / ’ \
\ / l l \\
1C ’/ / g
/ \ t /
/ \ \ /’ \\ [I /’
.// \ \ /
/ \ I \ \ I/ \ /
(I \ \l' \\ /
V
L argest. Strongest. Slifl‘est.
Fig. 2089. MODES or sounnme A 'rnnn.
There is this relation, that as the corners of the
largest (which is. of course square) are found by draw-
ring a diameter, bisecting it and drawing a perpendi-
cular each way from the middle 0 ; so, to get the
strongest, tr'z'scct the diameter and draw perpendicu-
lars opposite ways from the points an; and to get
the stifl‘est, qaarlrz'sect it at a h c and draw perpendi-
culars from a and c. The narrow sides of this last
‘beam are also those of a regular hexagon, or equal
to the radius of the circle.
Every one must perceive that a beam may have
much matter removed from the top towards each end
without losing any strength. The precise quantity
which is superfluous in every beam of equal depth
throughout, is the difference between the rectangle
and an inscribed semi-ellipse, which we know has little
more than 3-fourths of its area (‘7854! the ratio of
a circle’s or ellipse’s area to the enclosing square or
oblong.) Of course, if we made beams for ourselves,
instead of taking them out of a tree, we should omit
this excess by making them semi-elliptical.
A rectangular bracket would appear to have still
more useless matter hanging in the lower corner,—
and theory confirms this by showing the effective
mass, (when the weight is collected on the earl) to be
only two-thirds of the rectangle, viz. an inscribed
parabola of which the top of the bracket is the axis.
Architects cannot possibly add to the grace of this
form of bracket, whether deep or shallow, and we see
a near approach to it in all old brackets that carry
such a weight, as those of machicolations, balconies
with a stone parapetfand oriel-windows.
Brackets for a weight equally distributed from the
wall to the end, have, however, when rectangular,
half their matter superfluous, viz. all below a straight
line drawn from the top front edge to the springing
from the wall. This would be the form of one having

767
everywhere the breathing ‘depth at that point. Now
we might at first think- that an equal depth added
everywhere, (so as to give the form of a similar but
deeper bracket with the sharp front edge removed)
would be in strict economy. But this amounts to
adding a rectangular bracket, which we have seen
to be excessive in the front and everywhere else if
only sufficient at the wall. Let us add then the
depths, at every point, of an unsuperfluous bracket,
2'. e. the parabolic one, and thenwe shall find we have,
for the whole contour, a hyperbole, the well-known
profile of those old Doric capitals and corbelling
mouldings, designed to take an equally distributed
weight of this kind.
Thus it will be seen that the application of mathe-
matics to this subject has not, as yet, evolved any-
thing new, or which had not been the general prac—
tice, ages ago, of the architects of most countries,
who had been taught merely by instinctive observa-
tion, or what is termed “the eye.” On the other
hand, we must caution the reader against looking for
the application of such principles in the material
works of the age that investigates and explains them.
The indcfinable mass of motives and causes that, under
the names of taste, fashion, feasibility, &c., govern
modern material production, are, as Dr. Robison long
ago remarked, so various, complicated, andforeign to
nature and reason, that it is rare to find intelligible
design in our professed architecture and engineering.
STRING-COURSE, a projecting course of ma-
sonry on the face of a wall, forming a string, or hori-
zontal line. In Gothic architecture it consists of a
series of mouldings; in Italian architecture it is a
flat surface, either plain or enriched. Stringgcourses
serve to define the internal division of the building
into separate stories; they also separate one tier of
windows from another, and are useful in adding to
the horizontal lines of the building. The upper sur-
face of a string-course in Gothic architecture is
usually splayed or sloped for the purpose of throwing
off the rain. 1
STRONTIUM (Srétet), the metallic basis of the
earth strontz'a, or strohtz'tes, which was first discovered
in the state of‘ carbonate, at Strontian, in Argyleshire.
The metal may be obtained from its oxide by a pro-
cess similar to that described under BARIUM. It is a
white metal, heavy, oxidizable in the air, and decom-
poses water at ordinary temperatures. The protoa'irle,
SrO, or stroatz'a, may be prepared by decomposing the
nitrate by heat; it resembles baryta, and forms a
white hydrate soluble in water, and with a strong
attraction for carbonic acid. There is also a peroxide,
SrO . The native carhorzate and sahahate are used in
preparing the various salts of strontia. The chloride,
SrOl, crystallizes in colourless needles or prisms,
soluble in water, and also in alcohol, to the flame of
which it imparts a crimson colour. The nitrate,
SrO,NO,, is chiefly used for making reel-fire, as
baryta is for making green.
For reel-fire take 800 grains of dry nitrate of
strontia, 225 of sulphur, 200 of chlorate of potash,
and 50 of lamp-black. For green-fire, 450 grains of
768
STRYCHNIA—SUGAR.
dry nitrate of baryta, 150 of sulphur, 100 of chlorate
of potash, 25 of lamp—black. The strontia or baryta-
salt, the sulphur and the lamp-black are to be finely
powdered and intimately mixed: the chlorate of
potash in rather coarse powder may then be added
without much rubbing, or the sulphur will cause it to
explode. The red-fire composition is liable to spon—
tanecus ignition.
STRCP. See HONE.
‘3 STRYCHNIA, an alkaline base, which together
with Brucia, is contained in Nun oomica, in St. Igna-
tius bean, and in false augustura bark ; strychnia and
brucia are associated with a peculiar acid, the igasuric.
In order 'to procure strychnia, the seeds of nux
vomica are boiled in dilute sulphuric acid until they
are soft: they are then crushed, and the expressed
liquid is mixed with an excess of vhydrate of lime,
which throws down the alkalis. The precipitate is
boiled in spirits of wine of the sp. gr. 0850, and
filtered while hot. Strychnia and brucia are depo-
sited together, but they may be separated by cold
alcohol, which dissolves out the brucia. The strychnia
when properly purified crystallizes in small brilliant
octahedral crystals, which are transparent and colour-
- less. The taste of strychnia is very bitter; it is slightly
soluble in water, and is highly poisonous. It forms
salts with acids, and its formula is C4iHa-3N204.
Brucia is distinguished from strychnia by its ready
solubility in alchohol. It contains C44 H25N2 07.
STUCCO. See Mon'rxns and CEMENTS.
SUBERIC ACID is. formed by the action of nitric
acid on eerie. It contains CsHeOa + H0. ' Both this
acid and succinic [see AMBER] may be produced by‘
the long'continued action of nitric acid on stearic and
-mangaric acid. [See OILs AND Fara] Suberic acid
is a white crystalline powder,' sparingly soluble in
cold water, fusible and volatile by heat.
SUBLIMATION, a process of distillation by
which a body is raised in vapour by means of heat,
and condensed in a solid form. See Disrltnx'rron—
ALEMBIC—CAMPHOR—SULPHUR, &c.
SUBSAL’I‘. See METAL.
SUCCINIC ACID. See AMBER...
SUGAR. The juice of a large number of vege-
tables owes its sweetness to the presence of sugar.
This substance has from an early period of the world's
history been used in some form or other as an article
of food; indeed, the practice of sweetening food is
more ancient than the knowledge of sugar. The
ancients used honey for the purpose; and at a. later
period, when a sweet substance, which exuded from a
species ,of cane, was used, it was termed met arundi-
ynaceuni. Dioscorides, in the first century, refers to a
kind of honeyproduced by canes growing in India,
and in Arabia Felix, and named o'dKXapov, or sugar.
Pliny records the same fact, but remarks that it was
used only in medicine. Sugar- was not known in
Northern Europe as an article of food, until the time
of the Crusaders. The sugar-cane was introduced
into Cyprus from Asia, and about the» year 1148 is
said. to have been largely cultivated there; at which
time it was transplanted to “Madeira, and from thence,

in 1506, to the West Indies. There is evidence that
the sugar-cane was cultivated on the coasts of Anda-
lusia before the invasion of the Arabs, in the middle
of the fifteenth century. The Arabs had many sugar
factories, and with them probably originated the art
of boiling down the juice for the production of sugar.
The refining of the raw product is of later date, and
is referred to a Venetian. In the year 1597, a re-
finery existed in Dresden. Sugar-candy is mentioned
in the Atc/zemia of Libavius in 1595. Up to- the
close of the seventeenth century, syrup and honey
were used by the poorer classes in Germany for sugar;
and it was not until tea and coffee had come into
general use that sugar was regarded as one of the
necessaries of life. In the year 17 47, Margraf, a
German chemist, discovered that cane sugar existed
ready formed in the roots of many plants, espe-
cially in beet-root; but nearly half a century elapsed
before any attempt was made to establish a factory of
beet-root sugar; this was done by Achard, at Cumoom,
in Silesia, not, however, with any great success. The
first energetic impulse that was given to the manufac-
ture was by Napoleon, who, anxious to ruin the
colonial trade of Great Britain, ordered the blockade
of the continent, and in order to supply the demand
for sugar, which formed so important a part of our
commerce, he offered premiums for the best methods
of separating sugar from beet-root. The chemists of
France exerted themselves with their accustomed me-
thod and skill. Extensive experiments-were made on
the cultivation of the beet-root, and the best methods
of obtaining its juice, and extracting the sugar from it.
Factories were soon at work, and the first sample of
French beet-root sugar was conveyed at once to the
emperor, who received it ‘with joy, placed it under a
glass case as one of the choicest ornaments of his
drawing-room. He little thought that the extensive
and valuable series of apparatus invented or im-
proved by the French for the preparation of beet-root
sugar, would, at a future day, be adopted by the
English, and be the means of saving those very
colonies, which had prospered in spite of his opposi-
tion, but which at a later period, chiefly by the re-
nunciation of slave labour, had been brought to the
verge of ruin.
SECTION I.—Cnnnrcar. RELATIONS or SUGAR.
Sugar may be defined as a substance soluble in
water, possessing a sweet taste, and capable of under-
going fermentation. There are two leading varieties
of sugar: one the produce of the Arundo sacc/zarifin'a,
or. sugar-cane; also found in beet-root, in the sap of
certain species of maple, in the stems of palm, maize,
&c., and is known as .crgstaltine or cane-sugar: the
other is contained in grapes, figs, plums, and fruits in
general, and is known by the several names of granu-
tar-'01‘ grape sugar, glucose or sugar of fi'uits... Fruit—
sugar is however distinguished by some chemists from
grape-sugar, as will'be noticed more particularly here-
after. The property of submitting to the» action of
ferments and resolving itself into carbonic acid and
alcohol is peculiar to fruit or grapesugar ;- and when
SU GAR.
769
other varieties of 'sugar undergo this remarkable pro—-
cess, they are by the action of ferments first converted
into fruit or grape-sugar, and then undergo fermenta-
tion. [See Funnnnrnrron] Cane—sugar is further
distinguished from fruit or grape-sugar by its pure
and powerful sweetness, and the facility with which
it crystallizes. Grape-sugar is very inferior in sweet-
ness; it crystallizes imperfectly, and is usually ob-
tained in a granular state. It is accompanied in
fruits by malic, citric, or tartaric acid. It may be
produced artificially by the action of various agents
on cane-sugar, and also upon lignin, starch, and gum.
It forms the solid crystalline portion of honey ; it also
occurs in urine in the disease called clz'abeles. The
term sugar has also been applied to manna or mamzz'le,
which occurs in the juice of some kinds of ash, in
orchard trees, in celery, 850.: this kind of sugar, how-
ever, does not ferment. The juice of the liquorice
root, and a few other substances, are also classed
under sugar.
(lane-sugaen—Cane-sugar, when pure, is white and
brittle: it becomes phosphorescent by friction, and a
lump, on being broken, emits an electric spark which
is visible in the dark. Its density is about 1'6. It
dissolves in about 1-third of its weight of cold water,
but in a much smaller quantity of boiling water. The
spray: thus formed is viscid, and on being evaporated
at a moderate heat, deposits fine crystals of sugar-
camly, of which the usual crystalline form is a six-sided
prism commonly flattened and terminated irregularly~
The crystals are said to consist of 100 parts sugar, and
5'6 parts of water. A solution, saturated at 230°,
forms in cooling a granular mass or ladle/f, but when
the solution is rapidly boiled down until it acquires
a tendency to vitreous fracture on cooling, or when
fused at about 280°, or until a portion feat/ters or con-
cretes on being thrown off from a stirrer, it may be
poured out upon a marble or metal slab, and will form
a transparent amorphous mass on cooling. This
vitreous mass was formerly obtained by rapidly boil-
ing down a concentrated solution of sugar in barley-
water or sweet-wort, and hence the name of lav-ley-
szlym' applied to sticks of it, formed by cutting the
amorphous mass while hot into strips, rolling the
strips into cylinders, and then giving a spiral twist to
the cylinders. In this state the sugar is vitreous and
transparent, but after some time, especially if ex-
posed to air, it crystallizes, acquires a fibrous or
granular texture, becomes opaque first on the sur-
face, and then throughout the mass. Confectioners
add a small quantity of vinegar or tartaric acid“ to
the sugar, which retards this tendency to opacity.
The show-sticks which are kept in the windows of
grocers, &c. are made of coloured glass very accu-
rately resembling the barley-sugar in its freshest and
most transparent state. The tendency to crystallize
is also removed by keeping the syrup for a long time
at a temperature near its boiling point; but in such
case a portion of the sugar probably passes into
glucose.
Crystallized cane-sugar and barley-sugar consist of
CmHuOn: but if heated to temperatures between
VOL. II.

300° and 4-000 they lose two equivalents of water, and
become converted into caramel, 01211909, a black de-
liquescent substance, without the sweet taste of sugar,
not fermentable, and very soluble in water, to which
it imparts a brown colour. Caramel acts the part of
a feeble acid; it dissolves in alkalis, and forms black
precipitates with baryta and oxide of lead. If caramel
be further heated it loses water and forms a black
insoluble product. If the temperature be still raised
it disengages acid fumes, inflammable gases, and
a black bulky charcoal remains. All these products
may be obtained mixed by heating sugar rapidly.
The mineral acids, even when greatly diluted, and
most of the organic acids, transform cane-sugar into
a sugar which does not crystallize on being evapo-
rated: and when submitted to the action of polarized
light, it turns the plane of polarization to the left,
whereas the action of cane-sugar is to turn it to the
rig/ll. The acids which produce this remarkable
change do not themselves undergo any alteration.
It is probably the presence of acids in vegetable
juices which converts their sugar into glucose; for in
those cases where the juices are not acid the sugar
belongs to the cane variety.
Cane-sugar combines with bases and forms in cer-
tain cases crystallizable compounds, termed selecta-
wales. If a saturated solution of baryta-water be
poured into boiling concentrated syrup, there is de-
posited on cooling a crystalline mass of sace/tarale of
éclryla (BaO, (3121111011). This salt may be heated to
4241‘? without decomposition or loss of water; but it
is readily decomposed by carbonic acid: the sugar
enters again into solution, and the baryta is preci-
pitated.
Two combinations of cane-sugar with lime may be
formed: the first, by pouring a solution of sugar on
slaked lime in excess; when a compound is formed
which is very soluble when cold, ‘and may be sepa-
rated by filtration. If, however, the liquor be heated
to boiling, the greater portion of this compound is
precipitated, for it presents one of those exceptional
cases inwhich a substance is less soluble at a high
than at a low temperature. The precipitate may even
be washed in boiling water and then be re-dissolved
in cold water. This saccharide of lime, dried at 212°,
consists of SCaO. 2 (6121111011). If, however, hydrate
of lime be added in small portions to a concentrated
solution of cane-sugar until it ceases to be dissolved,
and alcohol be then poured in, a saccharide of lime is
formed, consisting of CaO. (3121111011. The solutions
of saccharides of lime have a strong alkaline reaction:
they attract carbonic acid from the air, and there are
formed on the sides of the vessel small transparent
crystals of carbonate of lime.
If protoxide of lead, in a minutely divided state,
he digested with a concentrated solution of sugar in
excess, an insoluble saccharide of lead is formed, and
the liquor retains a little oxide of lead in solution.
The same insoluble compound is formed by pouring
acetate of lead into syrup: saccharide of lead is then
precipitated by ammonia. On leaving the liquor and
the precipitate for some time in a warm place, the
0
0D
7'70
SUGAR.
precipitate assumes a crystalline texture. This sac-
charide of lead dried in vacuo consists of 2PbO.
Gel-110010. If heated to 350° it loses another equi-
valent of water, and becomes QPbO. 012E909. In
the two states of dryness the saccharide of lead, on
being decomposed by sulphuretted hydrogen, yields
a saccharine liquor, which, on being evaporated, re-
produces cane-sugar: so that the saccharine portion
has not undergone any permanent change in losing
2 equivalents of water. Hence the formula for
anhydrous cane-sugar is 01211909, and for crystallized
sugar 012E909. 2H0.
If a concentrated solution of 1 part common salt
and 4: parts of cane-sugar be evaporated crystals of
sugar-candy will first be found; when these have
been removed the mother liquor produces crystals
which have both a sweet and a salt taste; they are
soluble and deliquescent, and consist of NaGl.
2(GmHuOn.) Similar combinations are formed with
chloride of potassium and muriate of ammonia, and
they all render the manufacturer of beet-root sugar
liable to serious losses; for should the beet be grown
near the sea, so as to imbibe much common salt, these
various deliquescent compounds would remain in the
molasses or refuse of the sugar. The loss is, indeed,
much greater than at first sight appears: but it may
be estimated by considering the equivalents of the
substances concerned. Thus, if the composition of
cane-sugar be represented by—
12 equivalents of carbon or C12 = 72
11 ,, ,, H11 : 11 ,, oxygen ,, 011 = 88
_e_-
1 equivalent of sugar == 171
an'djthe composition of common salt by—
1 equivalent of sodium“ or Na = 24
1 ,, chloride ,, Cl = 36
1 equivalent of common salt = 60
it will be seen that the presence of a small quantity
of salt in the saccharine juice may occasion the loss of
a quantity of, sugar 6 or '7 times greater; for l equi-
valent of salt :: 60 unites with 2 equivalents of
sugar :: 34.2, and produces a compound = 4102, the
weight of which is 6%; times greater than the weight
of the salt in the compound, and it also retains at
least half of its weight of water saturated with sugar.
A beet-root factory established at Naples, near the
sea-shore, experienced heavy losses in consequence
of employing beet-roots grown in the neighbouring
fields; and we have also heard of similar losses in
a German factory from the use of beet grown in
a field in front of the graduation-house of the salt
works at Manheim. A‘ similar effect has been ob-
served with respect to sugar-canes. Those which are
grown near the sea make an inferior sugar to those
grown inland; the quantity of melasses is greater,
and the sugar more deliquescent. Mr. Kerr states,1
that on the windward coast of Barbadoes he has

(1) A Practical Treatise on the Cultivation of the Sugar-cane,
and the Manufacture of Sugar, by Thomas Kerr, Planter, Antigua.
London, 1851. ‘

tasted melasses as salt as if it had beenmixed with‘
strong brine.
The presence of sugar prevents the precipitation
by alkalis of many metallic oxides, especially in the-
case of the salts of the sesquioxide of iron and of the
oxide of copper, and the reason is, that the hydrates
of these salts are soluble in a solution of sugar to
which potash has been added.
The action of acids on cane-sugar has already been
referred to. It is complex, and varies with their
state of concentration and the ease with which they
are decomposed and part with oxygen. Strong sul-
phuric acid decomposes cane-sugar with energy;
charcoal, water, formic acid, and other products, are
produced. If equal bulks of strong syrup and sul-
phuric acid be mixed, the mixture, when stirred,
becomes brown, then black; it heats, boils up, and
forms a solid, bulky magma of charcoal. The acid
appears suddenly to abstract from the sugar the
elements of water. When the sugar is dissolved in
very dilute sulphuric acid and boiled, the effect is
similar to the action of the acid upon starch, glucose
being produced. Hydrochloric and several other
acids produce the same effect. If the boiling be
long continued, snclznlminc or snclinlrnic acial is
formed: these are brown or black uncrystallizable
products, formed by the action of acids and alkalis
upon several organic matters. Nitric acid, when
very dilute, produces similar changes to the sul-
phuric, but when stronger it produces saccharic and
oxalic acids, and at length these are resolved into
carbonic acid and water. ~
If a mixture of 1 part cane-sugar and 8 parts quick-
lime be distilled in a glass retort, the mixture swells
up at a certain temperature, gas is given off, and an
oily liquid, which may be collected in a cooled re-
ceiver. This liquid, on being agitated with water,
yields to it a product (031130) which may be obtained
in large quantities by distilling the acetates. It ‘is
termed acetone. The liquor which remains after the
action of water is also oily. It consists of C6H5O; it
boils at 130°, and is called metacctone. -
Fruit or grape angina—Some chemists distinguish
between the sugar of acid fruits, GlgHmOjg, and
glucose or grape ‘sugar GmHMOH. The former exists
only in the acid juices of vegetables; chiefly fruits,
such as grapes, currants, cherries, green gages, &c.
It may be obtained. by expressing the juice of these
fruits, saturating the acids by means of chalk, boil~
ing-the juice with white of egg for the purpose of
clarifying it, and then evaporating to dryness the
filtered liquor. The sugar thus obtained resembles
gum : it is very deliquescent; it dissolves in water and
dilute alcohol: it enters immediately into fermentation
on coming in contact with a ferment, and produces
alcohol and carbonic acid. It exists ready formed in
the ascending sap of the birch, and in the descending
sap of the maple. Cane-sugar is readily transformed
into fruit-sugar by the action of dilute acids evenjat
ordinary temperatures, and the effect is produced by
the organic acids, such as the tartaric, citric, malic,
and oxalic. Cane-sugar always undergoes this change
SUGAR.
771
under the action of ferments before it enters into
fermentation, and becomes converted into alcohol and
carbonic acid. It is generally supposed that‘ the
non-crystallizable sugar of all fruits is identical, but
this is an assumption merely: further researches may
lead to the distinction of various species. Fruit-
sugar turns the plane of polarization to the left.
Now, when the syrup of this sugar is left to itself
for some time, it deposits small crystalline grains, to
which, as Regnault remarks, the term grape-sugar
has been improperly applied. These grains differ in
composition from that of the sugar which produces
them, since it contains the elements of 2 equivalents
of water in addition; its formula being (3121-1140“.
In dissolving these grains in water a- syru-p is produced
unlike the original non-crystallizable syrup, which
turned the plane of polarization to the left, while the
solution of these crystalline grains turns it to the right,
as in the case of cane-sugar. But it diii'ers from cane-
sugar, not only in its crystalline form, but in its be-
haviour towards chemical reagents, and in its rotary
power. Cane-sugar, boiled with dilute acids, becomes
converted into a sugar which turns the plane of pola-
rization to the left, while grape-sugar undergoes no
alteration, and continues to turn it towards the right.
The crystalline grains above-mentioned, properly
called grape-sugar, (3121114014, form the white gra-
nules of sugar on the surface, and in the interior of dry
raisins. If the pulp of these fruits, divested as much
as possible of these white granules, be treated with
water, a saccharine solution is obtained, which rotates
.to the left. Diabetic-sugar is identical with grape-
sugar, as also is the sugar obtained by boiling starch
in a weak solution of sulphuric acid, then neutraliz—
ing the acid with chalk, and evaporating the filtered '
liquor. The granules in honey consist of this glucose
or grape-sugar, and the crust of sugar which forms
011 the surface of jams, jellies, and preserved fruits,
consists of the same substance. In such case the
cane-sugar used in making the preserves is changed
by the acid of the fruits into a non-crystalline sugar,
rotating to the left, and which in the course of time
becomes converted into: grape-sugar.
Grape—sugar crystallizes much less readily than
cane-sugar, and always in confused masses‘: it is less
soluble water than cane-sugar, 1- part of sugar
requiring 1% part of water for solution. Heiice
its taste is less sweet‘ than that of cane-sugar;
2 or 3 parts of theme being equivalent to 1 part of
the other. Grape-sugar dissolvesa- little more freely
in alcohol than cane-sugar. Solutions of grape-sugar
turn the plane of polarization to the right. At ‘,the
temperature of ‘ about 140° grape-sugar softens, and
at 212° is completely liquid. At the latteritempera-
ture it loses 2 equivalents of water, and forms a new
sugar, corresponding to 012111-2012, similar to that of
fruitsugar, although it continues to turn the plane of
polarization to the right. On evaporating a solution
of this new sugar a pitch-like mass is obtained, but if
left for a long time in contact with water, crystals of
grape-sugar are formed. Grape-sugar is converted
into caramel at high temperatures.

Grape-sugar combines less readily with bases than
cane-sugar. When boiled with alkaline solutions the
liquor becomes brown and evolves the odour of
burnt sugar; acid products are formed ‘which com-
bine with the alkali. If slaked lime be added to a
solution of grape-sugar, a large quantity of lime is
dissolved; the liquor displays an alkaline reaction;
it afterwards becomes neutral, and a precipitate is no
longer produced by the action of carbonic acid. ‘In
such case the sugar is transformed into glucz'c acid,
08H505, which forms soluble" salts with most bases.
* Grape-sugar also forms a crystalline compound with
common salt. Grape-sugar did‘ers from cane-sugar
in its action out-metallic salts; it reduces their OXJldES
either to a lower degree of‘oxidizement, or to the
metallic state, so that some of these salts are useful
tests of the presence of grape-sugar- If cane’sugar
be added to a dilute solution of sulphate of copper,
_. and the mixture be boiled, there'is little or no change;
but with grape—sugar the blue colour of the liquor he—
comes green, then yellowish or reddish brown, and
suboxide of copper or metallic copper is precipitated.
The best form of copper test for- the presence of
grape-sugar is. the soda tartrate of copper, obtained
by dissolving recently precipitated tartrate of copper
in a solution of soda or carbonate of soda: it forms
a deep blue liquor, which is decomposed at a boiling
‘heat on- the addition of a minute portion of grape-
2sugar, and a yellow hydrated dioxide of copper» is
thrown down, which becomes red on being filtered,
@washed, and dried. The soda tartrate of copper- is
lprep-ared of such a strength that 100 cubic centi-
‘metres of the solution shall be discoloured when
._ boiled with 1 gramme of grapesugar. For this pur-
pose, 100 cubic centimetres of’ the test solution are
boiled in a porcelain capsule, and the solution of
sugar-is added to-ilr from. a graduated glass, and it
is known that the volume of the saccharine solution
which produces. exact discoloration, contains exactly
1 gramme of sugar. This plan is also availablefor
determining the quantity of. cane—sugar in a solution;
for which purpose the cane-sugar must first becon—
verted into sugar, which turns the plane of polariza-
tion to: the left, by‘boiling-iti with a little~acid : lthC
copper solution will then be-acted on as in the former
case. The proportions in which cane and grape-sugar
are mixeéhsmay also be ascertained by determining,
first, the decolouring power. of ‘Fa-simple- solution of
i the mixture, and thenthe decolouring power acquired
I by an equallquantity of this mixture after the cane-
sugar in the mixturehas been boiled with an acid.1
The practical value of such a test will be better
appreciated when it is stated that large quantities of
. grape-sugar are manufactured for the purpose of
= adulterating brown sugar. For this purpose potato-
stareh, and sage, are saccharized by the action of
dilute sulphuric acid. 500 parts of starch are treated
with 10 parts of acid in 11000 of water. The dilute
acid is raised by means of steam to- a temperature
between 212° and 2%)"; and the starch,- made into a
(1) For more minute directions on this subject, see Begnault,
Cours de Chimie, tome iv.

302
772
SUGAR.
thin cream with water at 112° to 130°, is allowed
gradually to dribble into the dilute acid, the mix-
ture being constantly stirred. The starch is imme-
diately converted into dextrine, and in about 2% hours
the whole of the starch is used up, and in 15 to 25
minutes after, the saccharification is complete, the
steam is 'shut off, ‘the liquor transferred to another
vat, and the process is repeated. In this second vat
the acid of the liquor is saturated with powdered
chalk, added gradually, to prevent an overflow from
the effervescence.
When the sulphate of lime has
subsided, the clear liquor is drawn off and rapidly
evaporated to the density of about 126 (30° Baumé) ;
the sulphate is put on a strainer, and when drained,
the remaining sugar is washed out of it. The result-
ing syrup is then left to deposit sulphate of lime, and
is after-wards drawn 0E quite clear. In this condition
it may be used as a source of alcohol, or for sweeten-
ing coloured liquors, and for many other purposes. In
France it is largely used by the brewer in making the
thin beer so much in vogue on the Continent. For
some of its applications it requires to be deprived of
colour, for which purpose it is filtered through animal
charcoal. It is made solid by rapidly evaporating the
syrup to the density of 1°45 (45° Baum'é), and pouring
it into shallow coolers, where it concretes. In Paris,
glucose is prepared by Fouschard’s method, in which
the whole of the syrup is run off from the granulated
sugar, which is afterwards dried upon thick tablets
of plaster at a temperature of about 78°, and then
pulverized. During these operations the disagree-
able odour of potato oil is evolved to an annoying
' extent; this "may be avoided 'by'. condensing the
vapour, and applying the ‘heat to thev evaporation of
the syrup, as ‘will be "more particularly explained
hereafter.
Honeg. —The substance secreted by the nectarifer-
ous glands of flowers is collected by bees, and con-
verted by them into honey and wax. The former‘ is
used as food by the insects, and the surplus is stored
up in waxen cells or combs, in the form of a yellow,
viscid, and very sweet syrup. Honey, as already
noticed, contains two kinds of sugar—one resembles
the granular, or grape-sugar, the other is uncrystal-
lizable. It also contains a yellow colouring matter,
wax, gum, and sometimes mannite, The solid sugar
may be obtained from-granular honey ~‘=by the action of
strong alcohol, which dissolves the other ingredients.
I‘Ioney may be whitened by boiling it with water, fil-
tering, boiling with charcoal, again filtering, and eva-
porating the solution untiliit granulates on cooling.
Honey varies in its tasteandsmell with the age of
the bees and‘ the flowers on 'which they feed. The
honey of Trebizond is remarkable for-its deleterious
qualities, and is collected from poisonous plants.
There are'also' other examples of poisonous honey.
The vbest honey is produced by a hive-that has never
swarmed, and‘ is called virgin honey. The flavour of
Narbonne honey, so much admired, is said to be due
to the thyme and labiate flowers. on which the bees
‘feed; ‘this is imitated by adding a sprig of rosemary
to the honey from other places.

Honey is adultcrated with flour ; it may be detected
by its insolubility in cold water, and by the blue colour
produced by iodine. [See Wax]
Manna-sugar, or mannite, occurs most largely in
manna, but it also exists in beet—root, celery, aspara-
gus, onions, and other sweet plants. It is found in
the sap of the larch and other species of Firms; it
exudes from their bark, and also from several species
of ash, and it has also been met with in some kinds
of fuci. The purest manna of commerce, flake-manna,
is imported from Sicily and Calabria; it is of a buff
colour, light and transparent; it has a slight odour,
and a sweet but somewhat nauseous taste. Mannite
is procured by boiling manna in alcohol; it crystal—
lizes as the solution cools, and may be purified
by pressure. It forms about éf-fifths of the best
manna; the remainder being common sugar, and a
peculiar yellowish extractive matter, which is thought
to contain the aperient principle of manna. Mannite
may be obtained from the fermented juice of beet-
root, after the completion of the viscous fermenta-
tion; for which purpose it must be evaporated to a
syrup; alcohol must be added to throw down mucilage,
and on evaporating the filtered liquor mannite is de-
posited; it may be purified by repeated solution and
crystallization. Celery-root also'furnishes 6 or 8 per
cent. of manna.
Mannite is a white or nearly white substance, very
soluble in water; a concentrated aqueous solution
concretes. It does not ferment even when much
diluted, so that it may thus be separated from other
varieties of sugar which are converted into alcohol,
while the mannite remains undecomposed. Mannite
is not very soluble in cold alcohol, but abundantly so
at the temperature of ebullition. It fuses by heat
without loss of weight, and concretes, on cooling,
into a crystalline mass : at high temperatures it affords
similar products to common sugar. It is converted by
the action of nitric acid into saccharic and oxalic acids.
Oxide of lead is dissolved in its aqueous solution.
Crystallized mannite is said to contain CGILOG.
A kind of sugar has been discovered in several
species of agaricus and other fungi, and also in
morels ; it is supposed to be identical with mannite.
Liguorice-sugan—See LIQUORICE.
SECTION II.-—-Tun Susan-cane, AND THE Mxnurxc-
runs or Raw Susan.
The sugar-cane, Saccfiarum Qfiicinarunz, is a peren—
nial plant belonging to the family of the grasses. It
rises to the height of from 6 to 15 feet and up
wards, and attains a diameter of 1-15 to 2 inches. It
has a knotty stalk, and at each knot or joint is a leaf
and an inner joint. The whole plant is shown in
Fig. 2090, in which the stole s consists of 2 parts, the
one 8 formed of several peculiar joints or radicles,
varying in number from 5 to 7 , placed very near
together, ‘having at their surface rows of small points,
which are elements of roots. The radicles are sepa-
rated from each other by a leaf called the radiate Zeafi
These joints form the first .part, or primitive stole ,-
but as this would not be alone sufficient for a nume-
SUGAR.
773
rous filiation of joints, there are also several rows of
points, or elements of roots, on the cane joints, which
form, with the joints whence they issue, a secondary
stole s" ; they thus form roots until the joints are
sufiiciently numerous and strong to put forth and
sustain those which are to follow them and form the
stalk. This second part of the stole becomes very


{ff-7*. 5;"; .
ll/
/


Fig. 2090.
THE SUGAR-CASE.
1. Young cane in its first development.
2. Cane of 10 or 12 months.
3. A cutting planted with the cane shooting forth.
4. Transverse section of sap-vessels.
strong, and seems to serve for the filiation of the
remaining joints. The roots issue from the develop-
ment of the sap vessels, which are disposed in con-
centric rays round each point on the surface of the
joint. The sap vessels of the root, out transversely,
exhibit a circular surface of a cellular tissue, and are
covered with a skin which is first white, and then
_ joints.

brown or black. The roots are very slender, and
almost cylindrical ; about a foot in length, with a few
short fibres at their extremities. The number of joints
of the stalk or cane varies from 40 to 60, andeven 80
in the Brazilian cane. In the Otaheite cane the joints
are fewer and much further apart. The joints vary
greatly in their dimensions. The knots are not simple
enlargements, as in most
reeds, but are rings from ,1,»
to % inch wide; it or 5 rows
of semitransparent points go
round their circumference,
[see Fig. 2092,] and a semi-
transparent line divides the
outer from the inner joint.
At the upper part of this is
a slight circular hollow,
called the fleet, which is ter-
minated by the leaf of the
joint. The inner joint is en-
tirely_ subordinate to the
outer one in development
and growth; in it the juice,
after undergoing various
modifications, becomes con-
verted into crystalline sugar.
On every joint is a bud en-
closing the germ of a new cane. The sap vessels are
shown in transverse and longitudinal sections of the
cane in Figs. 2090, 2091.
The various parts of the cane grow and rise one
upon the other, so that each particular part is a whole,
and apparently pursues its course without reference
to other parts. The bud contains the germ tightly
enclosed within small leaves, and this germ is deve-
loped by the same laws in every part of the cane
where a bud exists. If the head of one of the radiclc
knots be cut off in an early stage, its buds then rc-
ceive the juices which would have nourished the head,
and sometimes become suficiently developed to throw
out 20 joints. After removing the radicle leaves the
first cane joint is usually discovered under that of the
fifth knot, and is known by the appearance of the bud:
if this be wanting it must be regarded as a radicle-
knot, and the following joint will have the bud : or if
not, then the next or seventh knot will have it. The
germ of the first cane-joint springs from the centre
of the last radicle-knot; which germ encloses the vital
principle of the cane and of the generation of the
The first, in forming itself, becomes the
matrix of the second, the second of the third, and so
on. There is always a degree of difference in the
various revolutions of each joint marked by the time
of its generation, so that, as Mr. Porter well remarks,
“ the joints of the cane may be considered as concen-
tric circles, the centre of which is always occupied by
a point which, expanding into a circle itself, is re-
placed by a new point; circles, which rising succes-
sively one upon the other, enlarge and arrive in a
given time at their greatest diameter.” 1 Under fa-

Fig. 2001.
SECTION OF CANE.
LONGITUDIKAL
(1) The Nature and Properties of the Sugar-cane, by G. R.
Porter. Second Edition, 1843. '
m
SU GAR.
vourabl'e circumstances i‘t'nappens that, just after the
first development of the cane joints, which form the
secondary stole, the bud of the first of these joints
throws out its radicle roots, and forms a second
fifliatiou on the first, as at fj; Fig. 2090'; the bud of .
the first cane-joint of this second filiation also some-
times develops and- forms a third; the second and
the third soon become very nearly as- forward as .the
first, The first joint requires
4! or :Ef'ofriitsl‘entire growth, and. during this
time from it in succession, the
decayiiio the maturation of each
joint;ijwlienitlrefleaves ofv the first .2 or 3 joints have
died’; ;tli‘erei'areabout .12 or 15 leaves at the top
rlth'e form of a fan. “ If the cane be con-
sidered in its vlnatiiral state it has at this period ac-
quired all its growth, and arrived at the usual epoch
of its flowering -; 'iflit} blooms, the principle of life and
generation passes entirely to the development of the
parts of fructification ; at this period, the joints which
spri'nglforth are deprived of their bud, and the sap
vessel's-with "they are supplied pass into the leaf,
whence l'itph'appena'that as the number of these ves-
sels isjconstantliydiminishing, the joints, in a similar
“ " ' I‘ ‘' manner, become longer, and
jljll . , I j ll l




their rind thinner. The last
‘ I.‘ _, joint, which is called the
u; j l’ ._
llllll
llllllll l
It
a
;k':
. arrow, is 41 or 5 feet long:
'' . is terminated by a panicle


I'm A‘ i -‘ l,
"' I of sterile flowers. 18 or 20
I i. ' ' / i’ inches high. If the period
r r of flowering is delayed by
cultivation, then the prin-
ciple of life passes to the
generation of new joints,
and this continues till the
sap vessels of the stole become woody, and do not
afford a passage to the aqueous juices. Fig. 2092
is a representation of a magnified joint, with the skin
removed to show the state and disposition of the
radicle points.
The cultivator distinguishes 3 species of canes.
1. The Chuck cane, which has dark green leaves, and
a thin but very knotty stem; it is indigenous to
India, and was transplanted thence to. Sicily, the Canary
Isles, the Antilles, and to South America. 2. The
Batu-via”, or striped cane, which has a dense foliage,
and is covered with purple stripes; it is chiefly culti-
vated in Java for the manufacture of rum.
Oéu/zez'z‘e cane grows most luxuriantly ,: it is the most
juicy, and yields the largest product. This variety is
chiefly cultivated in the WVest Indies and South
America. It becomes ripe enough for the mill at 10
months, and is more hardy than the other varieties.
‘The sugar-cane being originally a bog plant, re-
quires a moist nutritive soil, and a hot, tropical, or
subtropical climate. It propagated by slips or
pieces of .the stern- with buds on them, and about
2' feet long. ' It takes from ‘12 to 16 months, accord-
ing to the temperature, before it arrives at maturity.
Towards the flowering season the leaves ffall ofl, and
the‘ stem~ acquires a straw-yellow colour. Some
3. The '

planters cut the cane before the flowering season, but
generally some weeks after. The plantations are so
arranged that the various divisions of the fields may
ripen in succession. The land should be well sup—
plied with manure rich in nitrogen, but not contain—
ing much saline matter. After the harvest the roots
strike again and produce a fresh crop of canes; but
in about six years they require to be removed.
The time for cutting the canes varies, as already
noticed, with the soil and season and the different
varieties of the cane. The usual signs of maturity are
a dry, _smoo.th,]brittle skin ; ‘,a'heavy cane; a grey
pith, approaching to ._ brown; sweet and glutinous
juice. , The canes ‘should the {cut in dry weather, or
the juicewill "be diluted wiithran excess of water. ‘
The development of the 'Zhuds which form the secon-
dary stole of'aa plant that vhas been out, are named
mfloorzs, and they are first, second, or third, &c.,
according to the age of the root which produces
them. They diminish every year in length of joint
and circumference, and although they have not the
handsome ‘appearance of the original plant, they yield
much richer juice and produce finer sugar. The juice
from the ratto-ons 'is also said to ‘be more readily cla-
rified'than -;that from the plant cane. - >
The canes should be cut as close to. the stole as
possible, in order to give vigour to the 'rattoous that
are to spring from the {Old root: besides this, ‘the

"Fig. 2093._ THE can}; "HARVEST.
juice of the lower joints is: the richest in the cane.
The cane-top, with one joint of the cane, or two joints
if not quite ripe, must also be out OH. The canes are
tied up in bundles, and conveyed to the crushing-
mill, particular attention being paid that the supply
do not exceed the demand, otherwise the cut canes
would ferment and spoil.
The depressed condition of our West India colonies
has been referred quite as much to the defective cul-
ture of the cane, and the injurious methods of ex—
pressing and evaporating the juice, ‘as to political
causes. ‘The land has hitherto been most'imperfectly
worked by hand-hoeing ; a small hole is made for the
cutting, which is ‘but barely covered with earth; the
expressed canes, instead of being returned to the land
SUGAR?
7 7 5
as manure, are used as fuel; the cattle employed on
the estates are also miserably neglected. These and
other causes, which will be stated hereafter, are
sufficient in themselves to produce failure, especially
when it is considered that foreign planters have long
adopted better modes of culture. Mr. Kerr recom-
mends that the land should be deeply ploughed and
thoroughly pulverized; that the cultivation should no
longer be carried on by hand, but with implements, as
in the best farming inEngland ; and in putting in a
plea for the better treatment of the cattle, he reminds
the planter that the Psalmist, in praying for the pro-
sperity of his people, asks emphatically, among other
blessings, that “ our oxen may be strong to labour,
that there be no decay.” Mr. Kerr states, that it is
usual to plant the canes in parallel rows 6 feet apart,
and the canes 41 feet from each other in the row. He
recommends wider spaces, such as eight feet, between
the rows; and states that in Barbadoes, in 18417, 90
acres of cane, planted 8 feet by 4!, yielded 230 hogs-
heads of sugar. Some have even recommended to
increase the distance to 10 feet, and others have
advocated 8 feet square: that is,'the canes in rows 8
feet apart and 8 feet distant from each other. It is
also advisable to extend the planting over a period of
5 months; to begin early, so as to finish before the
rainy season sets in. In addition also to the many
advantages of returning the cane-trash to the land,
Mr. Kerr states, that by spreading it over the spaces
between the cane rows, it prevents the disastrous
effects of severe droughts. The cheap rate at which
coals can be sent from Great Britain to the colonies
makes it desirable to abandon the use of cane-trash
as fuel.
The juice of the sugar-cane consists of a nearly
pure solution of sugar in water, with traces of albu-
men, about % of gum, and a peculiar substance
resembling gluten or vegetable gelatine, which is de—
posited in large quantities in the vats in which sugar
is fermented for making rum. The juice also contains
of cerosin and a green vegetable wax, about 13,, to ,_g_,.
The mineral ingredients are similar to those in other
plants and vegetable juices, and consist of the sul-
phates of lime and potash, chlorides of potassium and
sodium, phosphate of lime, silica, &c. The juice is
sometimes colourless, but generally yellow: it is
made turbid by the presence of greyish globules
of suspended matter. Its taste is agreeable, but
rather insipid, and it has a peculiar balsamic odour.
After the cane has been passed through the rollers
and as much of its juice squeezed out as this imper-
feet method admits of, it is called cane-straw, bugasse,
or cane-trash. It consists of—-

Martinique. Guadeloupe. Cuba.
Otaheite Cane. Creole Cane.
Water 721 27 65-9
Sugar ............. .. 18' 17 8 17'7
Woody matter 9'9 9'8 16'4
Salts -—— 0'4 -_-
The trash is used as fuel in evaporating the juice,
as already stated. 100 parts of its ash consist
of—

Trinidad. Berbice.
45'78 462+
Phosphoric acid......... 3'75 8'12
Sulphuric acid ....... .. 6'64 7'48
Chlorine . 2'70 2'39
Lime................... 9'13 5'75
Magnesia.................. 3'65 15'53
Potash 27'32 11'87
Soda. 1'03 262
It is important to observe, that while the chemist
has proved that as much as from 17 to 20 per cent.
of crystalline cane-sugar exists in the cane or fresh
juice, the sugar-boiler in the colonies does not obtain
more than 7% per cent, or less than one-half. His
object is to convert the juice as speedily and with
as few operations as possible into raw sugar; hence
he has not been very active in improving on the old
method of manufacture, which entailsloss or deteriora-
tion of juice at every stage of the process: there is first
a large loss in consequence of the imperfect method
of expressing the juice from the cane, and, secondly,
a chemical change in consequence of long exposure
to the atmosphere at ordinary as well as at high
temperatures, whereby the crystalline sugar becomes
degraded iuto mucilaginous or non~crystalline sugar,
commonly called melasses or treacle. The juice of
the cane is purer, and contains twice as much sugar
as that of beet-root, and yet the manufacturer of
beet-root sugar manages, by means of improved pro-
cesses and apparatus, to make the beet-root juice as
productive as cane juice. It is true that the planter
labours under certain disadvantages which may not
be altogether compensated by a richer juice; the
sugar cane contains 2 or 3 times as much woody
fibre as the beet, which is soft and full of cells,
while the cane is fibrous and spongy, and is sur-
rounded by a hard integument difficult to submit to
pressure. Moreover, in the climate of the sugar
cane the ordinary temperature of the air is highly
favourable to fermentation, so that the danger of
decomposition is greater than in the case of the beet.
The fact, however, still remains, that while science
has been actively employed in perfecting the manu-
facture of beet—root sugar, she has, until recently,
done little or nothing for the manufacture of cane-
sugar; and now that attention has been fairly directed
to the subject, in consequence of the depressed con-
dition of our colonies, much of the beet-root appa—
ratus is found to be admirably adapted to the wants
of the colonial sugar boiler.
The original crushing apparatus of India was a
kind of squeezing mortar, made out of the hollow
trunk of a tamarind-tree, worked by a yoke of
oxen, the pestle or stamper being a strong beam, 18
feet long, and rounded at the bottom so as to squeeze
or crush the canes in the mortar. Squeezing-mills,
similar to those used for expressing oils from seeds,
[see OILS and FATS] were also used. There were
also other forms of apparatus before rollers were
introduced. Rollers of stone or iron were first used
with the axes in a vertical position; but the hori-
zontal was soon found to be more convenient and
economical. A common form of mill is represented in
2094; the rollers are of cast-iron, 24' inches in
776
SUGAR.
external diameter, with projecting rims to prevent the
canes from spreading over the sides: they are worked
by means of toothed—wheels attached to the axles.
The canes are introduced from an inclined plane P



/











llllllllllll lllllltllll ll“
CANE IMILL.
between the rollers R 11 1; in some cases R is grooved
to enable the roller more easily to carry the canes
through. The crushed canes are guided by the plates
g to the other side, between the rollers It] and 32,
where the fully crushed cane falls over the trough 'r.
The juice collects in the channel below, and flows
away to a reservoir. The cane should be crushed by
the first pair of rollers, and the juice be expressed by
the second pair, and the expressed spongy cane should
not be allowed to come again in contact with the
juice to reabsorb it. In some cases It1 is grooved
instead of It, and the distance between the smooth
rollers should be less than that between the other
two, or so narrow as barely to allow the cane to pass.
The velocity of the rollers at their periphery is about
3.}, feet per second.
Messrs. Pontifex and Wood have constructed some
improved mills to be driven by steam in preference to
water or wind, unless water-power be very abundant.
The mill consists of 3 horizontal rollers as before, the
space between the top roller and the bottom ones,
against which the canes first impinge, being less than
% inch; while that between the top roller and the
second bottom roller is only just sufficient to admit
a piece of paper between them: this space, how-
ever, is determined by the quality of the cane, the
thickness of the rind, &c. Motion is imparted to
the top roller by means of a large cog~wheel at the
back of the mill, and this communicates motion to
the two bottom rollers by means of small toothed-
wheels keyed on to the shaft of each roller. Slight
grooves are sometimes made in the top roller, for the
purpose of biting the canes more effectually in pass-
ing through the rollers; but as the grooves tend to
tear the fibre of the cane, and to render it unfit for
fuel, they are often omitted. The turn-plate between
the two bottom rollers is perforated to allow the juice
to pass through to the bottom bed-plate of the mill,
which forms a sloping cistern, whence the juice flows
into another cistern previous to its being clarified.
The canes must be spread evenly on the feeding-tray,
down which they pass through the first and second
rollers, over the turn-plate, and through the second
and third rollers. The distance between the rollers
is regulated by screws, and in order to diminish the
it l l llllllllillllltlll iitiii
Fly. 2094.


.__-_.
risk of fracture in the rollers, should the canes not be
distributed evenly over the feeding-board, friction
clutches are attached, so that when the strain on the
rollers exceeds a certain amount they cease to act.
Mr. Moore, in the otfice of Messrs. Pontifex and
Wood, has invented what is called a compensating
mill, in which the bushes, in which the two lower
rollers revolve when the mill is ovcrstrained, slide
back in their frame-work, and thus increase the dis-
tance between the rolls, thereby adjusting the space
between them to the work they have to perform, and
ensuring the mill against fracture, and obtaining a
more complete extraction of the juice: the required
pressure is obtained on the canes by means of a
heavily weighed lever.
Cane mills of great power are also made by Messrs.
Neilson 85 Co. and by’ Messrs. M‘Onie & Mirrlees, of
Glasgow. The former firm have lately sent to Cuba
a mill with rollers 30 inches in diameter and 6 feet
in length, capable of expressing 72 per cent. of the
juice of the cane. The latter firm have mills in which
the rollers are 28 inches in diameter and 5 feet long,
and moving at the rate of 2.1,— revolutions per minute
they are capable of furnishing from 2,500 to 3,000
gallons of juice per hour.
It is of great importance that the rollers should
revolve slowly. The result of repeated experiments
has shown that with a speed of 8 revolutions per
minute, only 46 per cent. of juice has been obtained;
while by reducing the speed of the same mill to 2%
revolutions, 70 per cent. of juice has been obtained.
Wind has been the usual power employed for driv-
ing the cane-mills. It is objectionable on account of
its irregular velocity, which renders it inferior to any
other description of power for crushing. It has been
ascertained by comparing the results from M mills in
Guadaloupe, driven by different kinds of power, that
with windmills of inferior construction the cane mills
produced only 50 per cent. of juice; with the ordi-
nary windmills the yield was 564 per cent; animal
power gave 585, water power averaged 618; and
steam 609.
From 12 to 14 tons of cane, fully ripe and in good
condition, are required for the production of 1,500
gallons of juice, the quantity required for making a
hogshead of sugar.
Mr. Bessemer objects to the roller-press, on the
ground that the time allowed for the pressure on the
cane is too short to displace all the fluid from the
congeries of cells in which it is stored; and that,
moreover, the amount of pressure on different parts
of the cane is unequal, since the rind and the knobs
are harder and more woody than the rest of the cane,
and are therefore more strongly pressed than the inter-
mediate parts, which are composed of soft cellular
substance and juice, and that hence the chlorophyl
and other matters are pressed out to mix with the
juice. The new press proposed by Mr. Bessemer is
represented in Fig. 2095. It consists of a crank-
shaft with 3 throws on it; an oscillating steam cylin-
der, 8103/, and solid pistons on plungers pp, fitting in
gun-metal tubes 0 c, perforated by small conical
‘SU GAR.
777
holes, the interior of each hole being the smaller to
prevent choking up. Above the tubes are hoppers
ff’, down which the canes so pass vertically, and as
the plunger makes its stroke in the direction of the
crank, the end of the plunger cuts off from the cane
a piece equal to the height of the tube, while its
further progress forces the newly-cut portion against
a mass of already crushed cane l, whereby the greater














‘ l.
. .i. jillllaupml
..;H'.llili' llili"



Fig. 2095.
will have moved forward under the hopper, and a
portion of the cane within it will have fallen down
within the tube. The reverse motion of the plunger
also cuts off alength from it and forces it against
the mass of cane trash l’, expressing the cane juice as
before. In this way the reciprocating motion of the
plunger acts on 2 pieces of cane at every stroke, and
a similar operation also takes place at the same time
in as many tubes as may be placed side by side
over the cistern. In this cistern is a self—regulating
heating apparatus for raising the juice to the tem-
perature required for defecation within 2 minutes
after its expression. The cane trash is produced in
a condition favourable for fuel; it falls upon a carrier,
and after being conveyed through a drying apparatus, is
delivered at the furnace-door of the evaporating pans.
It is stated that by this method the juice is larger in
quantity, less coloured, and more free from small
broken fragments, than when the pressure is per—
formed by means of rollers.
There is no doubt that by the old method of ex-
pressing the juice by means of rollers a considerable
portion of the sugar remains in the cane trash.
Dupuy states that as much as 410 per cent. of sugar
is thus lost. Something may be gained by distribut-
ing the canes more equally over the feed-board, and
it has even been proposed to dip the crushed canes
in water, and pass them a second time through the
mill. The deficiency of water and wood on most
plantations is an objection to this plan, which by
diluting the juice would require wood for fuel, and
the second passage of the cane through the rollers
would so lacerate the cane as to render it unfit for
producing the long flames required under the evapo-
rating pans on the old method of concentrating the

I‘ “Hm-y“
Ill l"

part of the juice is forced out; but as the cane con-
tains solid matter, the plunger, in finishing the stroke,
must force the whole mass of crushed cane forwards
a distance equal to that occupied by the solid portion
of the newly interposed piece; which movement of
the mass displaces at the open end of the tube an
equal portion of the mass which occupies it. During
the cutting off and pressing of this juice the plunger




l \v
.- 1‘: “sum. x L
I
| I it
. . n "
. ' 1 a. '_ ,
lllllh jpm- _ l , LM‘S
mama ifg,’ .J'.
l
6
l
I









my] mm“ W " "l-.lllllllllllllllllllllllllllllllllllllllllllllllllllllllllllll ll‘. .. . _n-ri an”
I ‘T . . 1,. .
11' \H on i J :Il'j _ l .1 ll rill


BESSEMER'S CANE rnnss.
juice. It would also be an objection to Payen's
proposal to employ 5 rollers 1t...'1a5, Fig. 2096,
enclosed under a hood of iron I, for the purpose of
confining the steam which it is proposed to inject by‘
the openings 8 s for the purpose of moistening the
cane in its passage between the rollers. Indeed all





Fig. 2096. Pn'nn’s cars MILL.
plans for increasing the produce of the juice which
leave the trash small and unfit for fuel have been
rejected by the colonies. The scarcity of fuel is so
great in some of the colonies, that it has even been
proposed, instead of expressing the sugar-cane, to cut
it in slices to dry them, and send them to Europe for
manufacture into raw or refined sugar. But the very
defect of fuel which led to this proposition would
evidently be the chief barrier to carrying it out.
since the fuel required for drying the canes would be
wanting.
The true remedy for the enormous waste that
attends the present mode of manufacturing raw
sugar, must be found in the application of a regulated
steam heat with coals for fuel, while the cane trash
shall be left to its more legitimate application of
manuring the land for future crops.
The waste of sugar by the old process has attracted
‘778
SUGAR.


the notice of French as well as English writers.
Thus Dumas states that of the 841 to 90 per cent. of
juice in the fresh cane, only from .gds to S-ths are
obtained from the presses: that this gds contain only‘
1:2 per cent. of the sugar actually existing in the fresh
cane, 6 per cent. being left in the trash which is used
as fuel: so that for every 80 millions of kilogrammes
of raw sugar imported into France, 410 millions of
kilogrammes have been burnt in producing them, the
value of which, about 20 millions of francs, is actually
thrown into the fire.
The clarification or deflection of the juice is pro-
duced by heat, which coagulates the albumen, and by
the addition of lime, which neutralizes the acid, and
renders some of the solid impurities insoluble. By
the old method an arrangement called the copper wall,
consisting of 5 pans, iron boilers, or term/res, as they
are called, walled together in a row, and heated by
one common fire, are used for the purpose. From the
juice reservoir below the crushing mill, the juice is
conducted into the clarifying pan, the fifth in the row,
the largest, and farthest from the dire. It should be
capable of holding the wholelofithe juice produced at
one crushing, and should be ready to receive the juice
almost as quickly as it is expressed. In some cases
two copper walls are built under the same shed, as in
Fig. 209 7. The proper dose of milk of lime, or temper,
as it is called, should be measured out by means of a
vessel graduated into inches, each inch corresponding
to 41% oz. of milk of lime. Not less than 5, or more
than 10 oz. are required to clarify 1,800 liters, or
about 10100 to T0300 the entire weight of juice. When
the proper temperature has been acquired, 10 liters
of juice yield 15 grammes of precipitate, containing,


Gum resembling cherry gum 50'25
Green matter (chlolophyll) . 10'05
Albumen, with particles of woody fibre... 22-78
Phosphate of 3'35
14-07
100'50
The phosphoric acid is originally present in the
form of an acid salt; hence if copper vessels be used


‘ l ‘1067/
\l/









j.
l
ll’1
“ l
l" l} {r
jl ill} in II’
.. f l
. j, I jfi jl
. lllllllllt



in. j .
* ils ll tritium

" . ""1"
--=.I






Fig!
THE BOILING EOUSE.
in clarifying, the metal is soon attacked and phos-
phate of copper formed: the lime converts this salt

into a basic phosphate, which combines with silica
and organic matters, and materially assists the preci-
pitation of foreign ingredients. A dense impure scum
collects on the surface, and is removed by skimming.
The juice is then passed through the other 4: teaches,
and heated until the evaporation is complete. During
this process a large quantity of thick scum is removed
by means of a perforated copper plate attached to
a handle. The formation of this scum is a striking
illustration of the defects of the system, for the scum
consists of nearly pure sugar, decomposed by heat,
together with the natural impurities of the juice: it
is passed into the melasses cistern, and is chiefly used
for making rum. As the bulk of juice is diminished
by evaporation, so the teaches are usually made to
diminish in size, the juice being passed from one to
the other by a copper ladle or dipper worked by hand.
The sugar is greatly injured by this repeated ladling
and exposure in small quantities to the atmospheric
air, and indeed the whole plan justifies the satirical
remark, that it is “ an elaborate and effectual means
of converting pure sugar into melasses and scum.”
And Mr. Kerr remarks, that “the whole system, from
the breaking up of the first clod of earth, to the roll-
ing of the hogshead of sugar into the waggon, appears
to have been expressly contrived for employing the
greatest possible amount of labour.”
When most of the scum has been removed in
a compact form from the clarifier, the juice is ladled
to the next pan, and as it diminishes in volume fresh
juice is added. The pans are in some cases on dif-
ferent levels, so that the juice may be drawn off from
one into the next below it, by means of a syphon;
but the pans are not usually terraced, so that the
juice has to be scooped from pan to pan. In the
second pan the concentration begins; the boiling
liquor throws up a scum, which the negroes collect
and return to the clarifying vessel. In the last pan
but one the juice is concentrated to 30° Baumé, and
it is then passed into the last and smallest pan, which
is situated directly over the fire. Here the boiling is
tumultuous, in consequence of the formation of gum-
stone, a deposit of lime consisting of—-

Basic sulphate of 1ime............... 92'43
Carbonate of lime 1‘35
III.‘I'QOIIIOQ'IOQIIQI‘I‘CII Phosphate of copper.................. 1'41
99'89
with organic matter. The panstone forms more or
less in all the boiling operations: it causes the juice
often to be over-heated, the sugar to be burnt, and
caramel to be formed, as when the incrustation cracks
and the juice comes in contact with the hot metal.
The crust is from time to time removed by heating
the empty pan to redness, when, in consequence of
the greater expansion of the metal, the crust breaks
up and peels ofl. Sometimes the last and smallest
copper contains a slapping-teach a smaller vessel of
the same shape, with a valve at the bottom worked
by a handle. This vessel is let down by a crane into
the pan, removes the sugar from it and conveys it to
the coolers. In some cases, as shown in Fig. 2097, the
SUGAR.
_7.7_9m
concentrated syrup is discharged down shoots into
the coolers. Sometimes the term teacke, or tag/ate,
is applied only to this last vessel, in which the syrup
is reduced to the gr'mzulaz‘z'ng point, or sufficiently
concentrated to separate on cooling into grains of
sugar. The required consistency is ascertained by
taking a small portion of the syrup upon the thumb,
then bringing the forefinger in contact with it, and
again separating them, noting the length ‘to which a
thread of syrup can be drawn before it breaks; if it
extend to about half an inch in length, the sugar is
judged to be fully boiled. This trial by the tow/r
is supposed to have given the name of tear/ac to the
pan. The coolers are shallow open vessels, each
capable of containing about a hogshead of sugar.
They are of wood, with thick sides, that the cooling
may be gradual. In about 24.‘ hours the sugar grains,
or forms into a soft mass of crystals, imbedded in
molasses, which are separated in the curing-boasts, to
which the soft sugar is removed. The sugar in the
coolers is frequently stirred with iron rods, to pro-
duce a uniform temperature and consistency. The
curing-house is a large building, the lower part of
which is lined with lead, forming the melasses’ reser—
voir. Over this, on an open framing, are placed the
hogsheads or potting-casts. In the bottom of each
cask are bored several holes an inch in diameter, into
each of which is placed a plantain stalk, or a crushed
cane, of sufficient length to reach to the top of the
hogshead. The soft sugar being placed in these
casks, the melasses gradually drain away through the
spongy stalks or canes, leaving the crystalline portion
tolerably dry. In 2 or 3 weeks, or 5 or 6 if the
mass be mucilaginous and the grain small, it is fit
for shipment; a further drainage of melasses takes
place in the hold of the vessel, and even after this
there are melasses entangled with the crystals of the
raw sugar, to the injury of its quality.
Such is the raw sugar of commerce: it varies
greatly in quality, but really consists of a crystalline
flour of pure sugar, moistened throughout with me-
lasses, often to the extent of one—third of its weight,
and often more than the crystals can contain. Hence
as it attracts moisture from the damp air of the
vessel and “becomes more liquid, it escapes from the
crevices of the casks. It is calculated that about
12 per cent. of sugar is lost in this way from
the English colonies alone, or about 27,000 tons
annually.
In places where the sugar is not packed in hogs-
heads for the sea voyage, it is set to drain in the curing-
house, in wooden moulds of deal. The syrup which
drops from the moulds, or from the hogsheads, into
a cistern, deposits on cooling a sugar, the grain of
which resembles fine sand, and forming a layer on the
bottom several inches in thickness. This inferior
product is called by the French planters, fond cle cis—
terrze. It averages ab0ut'10 per cent. of the raw
sugar, depending on the temperature at which the
sugar is placed in the moulds. It has a moist and
smeary character, and is an admixture of various
salts, of gelatinous silica, mucus or gum deposited

from the refuse syrup, or mother-liquor, of the first
crop of crystals.
The defects of the old system most plainly appear
from the various modes adopted of calculating the
loss. We have already given one or two estimates,
and will conclude this section with one or two more.
From every 1,000 parts of sugar~cane the old process
yields from 60 to 80 parts raw sugar, and 25 to 30
of melasses; while according to chemical analysis
the yield should be 180 to 200 parts of crystallized
sugar. The following table has been drawn up from
a large number of comparative results :—
In 1,000 parts—-
Raw Sugar r79 .... .. 73
Me1asses................ 30 .... .. 27
ass .... .. 395
Water 505 .... .. 505
Thus of the 180 to 200 parts of crystalline sugar
in 1,000 parts of cane, there are obtained from 7 3 to
7 9 parts of raw sugar: 18 to 20 parts of melasses;
cane trash, 28 to 33 ; and waste in the pmoess of
manufacture, from 418 to 61 parts.
Mr. Kerr also states that of the 1,500 gallons of
juice required to make a hogshead of sugar netting
15 cwt. in the English market, the planter does not
get a return of more than 0 per cent. of moist musco-
vado sugar, and that of very inferior quality.
SECTION III.-— IMrnovnn SYsrnM or MANUFACTURING
Raw Scorn.
The various improvements in the rude process of
manufacturing sugar described in the last section
have for their objects the preservation of the juice
from fermentation, and its concentration with as little
agitation and exposure to the air, and at as low a
temperature, as possible. Several proposals have been
made for removing or diminishing the causes which
lead to the rapid fermentation of the juice. Among
other plans, Dr. Mitchell proposes to destroy the
vitality of the glutinous fermenting matter, and to
coagulate the albuminous substance in the tissue of
the cane, by plunging the canes into some boiling
liquid as soon as possible after they are cut. This
plan would prevent the albumen, &c., from passing
into the juice by expression. From some experi-
ments made on this subject, it appears that ”a colour-
less juice was obtained; it was full of floating feculae
which immediately subsided, and the juice ibeing de-
canted 05 and boiled down without the addition of any
time or temper, or any necessity for skimming, fur-
nished a pure white sugar. By this process, the juice
is diminished in quantity, but increased in density.
Some of it was kept for 18 hours “without undergoing
any change.
M. Payen recommends the use of sulphurous acid
or of bisulphite of lime for preventing the rapid fer-
mentation of the juice. He advises that the ends of
the canes be dipped into a solution of the bisulphite
as soon as they are cut. An infusion of tannin or
nut-galls has also been recommended for the separa-
tion of the deliquescent matter and soluble salts.
As the crushing-mill is generally on the ground,
the juice is raised to the clarifying vessels by force-
780
SUGAR.
pumps of peculiar construction, and with very little
agitation. For this purpose it is admitted into an
apparatus called a mom‘c—jus, Fig. 2098, from which
it is forced up a pipe
by the pressure of
steam on the surface
of the liquor. J is
the vessel for receiv—
ing the juice, which
passes into it by a pipe
and cock P; s is a pipe
for supplying steam
for forcing the juice
up AA; a is an air-
cock, through which
the air escapes on the
admission of the juice:
the pipe attached to
this cock dips 2 or 3 inches below the top of the
cylinder, so that the juice never rises above that
height; the space above being filled with air, acts as
a cushion between the steam and the cane-juice,
thereby preventing the juice from being heated to
the temperature of the steam; M is a man-hole. It
will be seen that the pipe A is not only continued to
the bottom of the receiving vessel, but dips into
a sunken receptacle, by which means all the juice is
collected; for it is of importance not to leave layers
of juice at the bottoms of vessels to ferment and
damage the fresh juice afterwards added.
Steam-heat is used for the clarifying vessel, into
which the juice is raised by the monte-jus. This
vessel consists of a hemispherical copper pan r, Fig.
2099, surrounded by a cast-iron jacket J, and steam
is admitted into the space between the two, the sup-
ply being regulated by a valve 7). On the top of the
copper pan is fixed a lay/it‘ course L L, or copper band,
from 15 to 18 inches deep, to prevent the scum from
frothing over. The plug 1) in the bottom of the pan
is furnished with two or three holes, through one of
which the clarified juice passes down the hollow of

Fig. 2098.

Fig. 2099.
the plug to the smaller channel of the two~way cock
c. When the clear liquor is run off, the plug is
removed by means of the handle 5, and the thick scum
and sediment pass off through the larger way. The
condensed steam passes away by the pipe 20. a is a
CL ARII‘I FR.

cock which is opened for a short time on the admission
of steam, to allow the air to escape. The elarifier being
filled with juice, steam is admitted and the temperature
raised to 176° Fahr. Any particles which rise to the
top of the liquor are skimmed ofi’, and milk of lime is
poured in in quantities just sufiicient to neutralize
the acid, which is ascertained by the frequent use of
litmus paper. The heat is continued until there is
formed a thickness of 3 or 4 inches of scum, consist-
ing of most of the impurities of the juice. In about.
10 or 12 minutes from the first application of heat
the scum should be well formed and about to break
up. The moment it begins to crack the steam is
shut off, and the liquor being left for 15 to 20
minutes, the lighter impurities will have mostly risen
to the surface, and the heavier ones sunk to the
bottom, while between the two is a pale and beauti-
fully clear liquor. The hollow plug which is ground
into the hole in the bottom of the pan, is now turned
by its long handle it so as to throw open a hole in the
side 3 or 4: inches from the bottom, and consequently
above the subsided impurities: by this opening the
clear liquor escapes, and proceeds along the small
channel of the two-way cock until scum begins to
appear; the cock is then turned on to the larger way,
the plug is altogether removed, and the heavy matters
and scum pass out through the hole, and are con-
veyed to a cistern, placed in bags, and the juice
squeezed out. The juice in the clarifier is never
allowed to rise above 208° or 209°, or the impurities
would become so mixed up with the juice as to be
incapable of separation; a result which will also be
attained unless the process be speedily conducted.
The clarified juice still contains matters in suspen-
sion, which require to be removed by filtration. The
filters consist of fine copper-wire sieves in sets of 4:
or more each, the one above fitting into the one below,
the mesh of the lower sieves increasing in fineness.
The bottom sieve has a flannel bag attached, for the
separation of the finer impurities and the feculent.
matter. The flannel, or bagjilt‘er, is sometimes used
without the sieves in an ar-
rangement shown in Fig.
2100, in which 8 is the cis-
tern for containing the juice,
fly’ the filter bags. The fil-
tered sugar liquor is next
passed through filters of bone-
black or animal charcoal, in
large slightly conical vessels
of copper or iron, from 6 to
12 feet high, each furnished
11/ r


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with a perforated false bot-
tom over which a filtering cloth is spread. The cistern is sometimes closed in at the t;
top in order to preserve the ‘
warmth of the liquor, and "If" .;


s 11"’:
thus facilitate its passage
through the filter. In filling Fig- 2100-
in the bone-black, the first few inches are pressed ‘
compactly down; after which it is filled lightly, but
sueaa.
{781
evenly, to within a short distance of the top, where '
a space is left for the accumulation of the cane juice.
Fig. 2101 represents a vertical section of one of the
charcoal filters used in France. Upon the false per-




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forated bottom a filter—
cloth is spread, and
upon this the charcoal
c is placed, first in
Well packed layers,
and afterwards a little
more loosely. Another
cloth is placed on the
top, and upon that a
perforated plate of
metal. The syrup to
be filtered is let in
from the cistern s, and
the supply is regulated
by a ball-cock be, a
certain quantity being
always kept at the top of the filter to prevent the
charcoal from drying and dividing into vertical
channels or cracks, and forming what the French
call de faassea coz'es. To allow the syrup to accumu-
late in the bottom reservoir of the filter, it is neces-
sary to let the air escape, for which purpose the tube
t t is provided. At m is a man-hole for cleaning out
the filter when required. The object _of filtering is
to remove all vegetable colouring matter and any
excess of lime that may have been accidentally added
in the clarification, together with mineral salts, such
as sulphate of lime, originally present in the juice.
About 5 tons of animal charcoal are required for
every 100 tons of sugar made. After this the char-
coal is reburnt, and thus its useful properties are re-
stored to it. '

Fig. 2101.
See Bonn. .~
The filtered liquor is now ready for evaporation,
which according to the improved processes may be
conducted either in the vacuum-pm or in open pans,
containing a coil of steam-pipe. The usual plan is to
concentrate the liquor in open pans to the density
of 259 to 28° Baumé, up to which point it is not
greatly acted on by the atmosphere. The evaporators
used for this purpose are large iron vessels such as E,
Fig. 2102, with copper pipes at the bottom bent round
as shown in the plan, Fig. 2103, the extremities of
which terminate in a straight gun-metal tube passing
through stufling-boxes H H : the pipe .9, which conveys
the steam, is at one end of the straight tube, and the
pipe which discharges the condensed water at the
other. By this arrangement the pipes can Joe raised
up out of the vessel for the purpose of cleaning it
thoroughly; for if the cane juice be allowed to hang
about the pipes, it will become acid and infect the
next charge. By means of the lever L the evaporator
can be tilted into the position shown by the dotted

lines, for the purpose of better running 0d‘ the evapo-
rated juice by the cock 0. In these vessels the juice
.-- "1‘...-
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;-
l I pp: ,nrllpaint-quill; ill ill a} l \ llll l: =1
llllllllllllll l lll l till ll i
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Fig. 2102. EVAPQRATING PAN.
Elevation.
Fig. 2103 . Plan.
is evaporated to about 27° B. before going into the
vacuum-pan.
- Another arrangement for concentrating the juice
for the vacuum—pan is shown in Fig. 2104', and it pos-
sesses the great advantage of employing the waste
steam of the vacuum-pan. It consists of a series of
straight copper pipes ss placed one above the other,
with the ends fixed in cast-iron boxes or united by
curved end pieces as in the figure. The steam gene-
rated within the vacuum-pan is admitted within these
pipes ; and the weak juice which is to be evaporated
‘is allowed to trickle down in a shower over these
pipes ; an arrangement which reminds us of the thorn-
walls employed inGermany, for evaporating the weak
brines used in the manufacture of common salt. [See
~SODIUM, Fig. 2009.] The weak juice is contained in
a vat s, from which it passes along a pipe into a
serrated trough j’, and falling in drops from pipe to
pipe it-condenses the steam within, while itself becomes
‘greatly heated, sends off vapour, and falls in a more
concentrated form into the trough R, from whence it
passes into a vat which feeds the vacuum-pan. There
is, however, a remarkable adjustment of temperature
in this apparatus‘, which is well adapted to the con-
ditions of the process. As the cane—juice in passing
over these pipes becomes more concentrated, and con-
sequently more liable "to injury from heat, the conden—
sationof the steam within the pipes tends to mitigate
the temperature, and to prevent the lower pipes from
becoming too hot. The condensed water issues out
through the pipe :9, which is placed in connexion with
a small air-pump, for the purpose of assisting the main-
tenance of the vacuum in the vacuum—pan, and the flow
of steam along the pipes as in the required direc-
tion. Thus, it will be seen that this apparatus is as
ingenious as it is economical: the steam inside the
782
SUGAR.
pipes parting with its latent heat to the juice on the
outside, the one is evaporated and the other con-
d





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Eig.,2104. ooumzusnn AND EVAPORATOR.
densed, thus‘. enabling the vacuum-pan. to perform
twice as much: work: as itcoul’d otherwise-get through.
The concentrated juice is next passed, into the
vacuum-pan, where the evaporation is completed; un-
less a ‘sugar of very superior quality be required, in
'which case the syrup is slightly heated for the pur-
pose of increasing its fluidity, and is again passed
’th rough the I charcoal filters.
The vacuum-pan depends for its action on the prin-
ciple that liquids boil at greatly reduced temperatures
' when" relieved from the pressure of the atmosphere.‘
ESee EBULLI'rroNJ The term vacuum-pan, however,
is not very appropriate, for if all the air were‘reinovcd
at the commencement, the space would'become ra-
pidly filled with‘ steam from'the heated liquor, andan
amount of pressure equal to‘ that of the‘ atmosphere
be again established, unless means were taken for
- drawing oii'the vapour as fast as it formed, and even
then an actual vacuum over the surface of ‘a liquid
could never be established. The vacuum-pair origin-
ally patented by Howard in 1812, has been‘ of‘ great
value in the chemical arts, not only in the prepara-
tion of sugar, but also of medicinal extracts and
other substances, the concentration of ‘which, at their
ordinary boiling points, was always dangerous,-
generally led to the decomposition or deteriorationT
of the vegetable juices. It has gone through a
great variety of improvements since the- date of its
introduction. It is represented in its most approved
form in a steel engraving, which is copied from'the
~pan, manufactured by ‘Messrs. Pontifex 85 Wood,
~which formed so conspicuous an object in the ‘Great
‘ Exhibition.
of boiling 80 tons of sugar in 244 hours.
.sists of a copper pan, with a- ‘cast-iron jacket J, and
arrangements for admitting steam between the‘ two.
-Within the pan and corresponding with its curvature,
-is a worm or coil of copper pipe 72, through which
. steam is passed for the purpose of boiling the juice.
>At ‘the top of the pan and of the inner jacket is a
It is 8 feet in diameter, and is'capablc'
1 The section,‘
Fig. 2105,'wil1 also assist‘ the explanation. Iit con-'

copper dome 1), fixed tightly by means of flanges.-
The steam generated in the vacuum-pan by the evapo-

Fig. 2105. VACUUM—PAN.
ration of the juice, is removed by the condenser,
Fig. 2104', already described, or the steam is drawn
off into a condensing box, and condensed by the in-
jection of cold water, as described under STEAM-
ENGINE, Figs. 2043, 20445, 2053; by which means a
partial vacuum is produced; and is further assisted by
means of a powerful air-pump, which removes the
Water‘used-in condensation, and also gets rid of the
‘ air which is carried in with the water. Now as air is
far ~more 'diflicult to remove than water, .this method
:of condensation ‘by injection is far inferior to that by
"the condenser, Fig. 21011, which does not require that
water should come in contact with the steam, so that
no air enters'the pan; there is thus a saving of 40 to
50 per cent. of fuel, and consequently the vacuum-pan
'can be used in places where water is too scarce to
command the large supply required for‘ injection.
There is also a saving in the size of the steam boilers
required, in the freight, in the setting, and in the
daily 'stohing. ‘Besides this,‘ the air—pump is not
wanted, and thus the power required for working it is
‘ savedl A small air-‘pump is indeed generally attached
to the condenser, in order the more quickly to get rid
of‘ the water formed by the condensation of steam in
‘the pipes, and also to remove air from the pan at the
commencement of 'the day’s work. The condenser
may be applied with advantage to steam-engines, pro-
ducing a vacuum, according to the state of the atmo-
sphere, of fr01n'26 to 30% inches of mercury; and when
‘attached to high—pressure engines used in the manu-
facture'of sugar, not only may the waste steam of the
‘engine be employed in evaporating the Weak cane
juice in the same manner as‘ the steam from the
vacuum-pan ; but it saves and returns to the boilers
the condensed water in a hot and pure state; and
lastly, by the addition of a small air-pump, it converts
a high-pressure into a c'ond'ensz'i'zg engine, thus increas-
ing the power of the engine and diminishing the cost
of fuel required to work it. _ - - -
A
: jig 13.1. 171.. @5227: :
v - mflnfifi ..1 3..

SUGAR.
was
- 'We will now proceed with our description of the
various parts of the vacuum-pan. The copper worm
or coil of pipe through which steam passes for heating
the juice, is marked 12; the space between the pan and
the jacket J is also occupied by steam. nris a man-
hole with a movable‘ gun-metal. top ground into its
collar, and taken off'fpr the purpose of repairing or
cleaning the pan. st is" the valve for supplying steam
to the worm; v isa smaller valve for admitting steam
into the interior of the pan for cleansing. _79 s is the
proof—stick for drawing “out a sample of sugar during
the process of evaporation, without disturbing the
vacuum: it consists of a piston with a receptacle in
it for receiving the sample of sugar, into which it
is plunged by being passed down a barrel soldered
into the dome, and dipping below the surface of the
liquor; and the piston is so arranged that it can be
drawn out of the barrel to a sufficient extent to allow
the sample of syrup to be taken out without admitting
air into the vacuum. By means of a cock of similar
construction, a little piece of butter may be intro-
duced into the pan, to modify the violent ebullition
to which the liquor is sometimes liable. t is a ther-
mometer for ascertaining the temperature at which
the syrup within the pan is boiling; and 6 a baro-
meter or vacuum gage for ascertaining the amount
of pressure within the pan. s is a measure of the
capacity of about 35 gallons, for regulating the quan-
tity of juice admitted into the pan; it is furnished
with a pipe and cock a dipping into a cistern below
and which supplies the pan. 8 is the pipe and cook
for conducting the measured juice into the pan. g is a
glass gage partly enclosed in a brass tube for showing
the quantity of juice in the measure ; c’ is a pipe and
cook leading to the pan, through which the vacuum in
the pan acts upon the juice in the cistern and draws
it up into the measure, in filling which the cooks
c and c’ are opened and the juice is drawn up, and
when the measure has received its proper quantity,
these cocks are shut, and the cock 8 is opened; but
as the cold liquor admitted into the measure will have
condensed the vapour admitted into it from the pan,
there will be a greater ‘amount of rarefaction in the
measure than in the pan when the cock 0' is opened,
so that juice will not flow into the pan until air is
admitted into the measure, for which purpose‘ the
cock 0’ ’ in its cover is provided, and ‘this being
opened, the‘ juice flows into the pan. 0 is an over—
flow vessel or r'ecez'ver'for catching any liquor that
may boil over from the pan, the amount of the over-
flow being indicated by the gage y’; a cock at the
bottom of 0 allows this juice to be racked off. A is a
small air-cock in ‘the arm-pipe, which‘ conducts the
vapour from the pan to the condenser. In the dome of
the pan are small peep-glasses, e, one on each side; so
that by looking through one, the other affords sufii-
cient light to watch the progress of the boiling in the
pan. The sugar is run out of the pan bya gun-metal
saucer G, ground into a socket is attached to the pan;
the saucer is raised or lowered by means of the lever Z.
In some cases a cock is substituted for the saucer,
_ and is brought by means of a Windlass wheel within

the control of the sugar-boiler, who can work it
without having to leave the vacuum-pan stage. The
handle it in the steel—engraving is intended for ‘a
similar object. 1
In addition to the above apparatus, there is an ex-.
pansion vessel, for reducing the pressure of the-steam
to the point required in the vacuum-pan. It is a
large cylinder of plate-iron c, Fig. 2106, into which


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c
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n
_-
~¢-- =..-
._,_~ . _r _'
r..-‘--_.:_"—-—-_.T’r;“;i if“ ~.—--.l~"—_v'v-
§;-_- ~
‘Fig. 2106. EXPANSION vr-issEL.
steam is admitted by the pipe s. At the top of the
vessel is a valve v, loaded to the required pressure,
through which steam escapes as soon as the pressure
in the vessel rises above that point; the. expanded
steam is then led away to the vacuum-pan through the
pipe P. I) is a valve for opening or closing the way
between the boilers and the expansion vessel. 9* is a
small safety self-regulating valve. Messrs. Pontifex &
I'Vood have improved on the above common method of
expanding, which occasions a waste of all the steam
above the required pressure, by the contrivance of a
peculiar valve 0, which is a hollow cylinder, containing
alsolid piston or plunger loaded to the required weight
by 20, so that as soon as the pressure exceeds the
counter-balancing weight, the piston, against the
bottom of which the steam acts, rises and partially
closes a valve which regulates the admission of the
steam,~and when the pressure is so reduced; that the
weight is able to force‘ the‘ piston down, the valve is
again fully opened- . ~ . I.
In operating with the vacuum-pan the‘ syrupis run
in- as. quickly. as possible, until the whole of the heat-
ing surface is covered :. the steam is then turned .on,
and the temperature of from 180°.‘to 190° main-
tained. When the ‘syrup begins to granulate or form
crystals the temperature is lowered to 1609, and just
before the evaporation is completed, and the sugar
ready to be let out, the temperature is reduced to 145°,
orthe lowest temperature at which proof-sugar boils
at 3 inches above a perfect vacuum. The sugar-
boiler takes out a sample of syrup by means of the
proof-stick, and drawing it out against the light be-
tween his finger and thumb, ascertains that the crys-
tals are in a sufficiently forward state: he, then adds
another measure-full of syrup to the pan, and the same
process is repeated until the whole charge is admitted.
7845
SUGAR.
As each successive measure-full is admitted, the crys-
tals increase in size to the end of the operation, those
first formed acting as nuclei. A skip or pan-full of
concentrated sugar should be made in from 1:}; to 2
or 2%— hours from the commencement of boiling. If
fine grained, the sugar requires a ‘greater quantity of
syrup to be admitted at each charge of the measure,
and vice versa’. The concentrated juice, or proof-
sugar, consisting of a large number of small crystals
floating in syrup, is let down at 14150 through a cook
or valve in the bottom of the pan into a vessel called
the heater, which consists of a copper pan with an
iron jacket, and is similar to the clarifier, except
that it is larger and has no light course on the top.
It is furnished with a condense-box to allow the con-
densed steam to escape without loss of steam: this is
a cast-iron box with a pipe at the bottom, in which is
a valve attached to a float-stone : as the water enters
the box the float-stone rises, opens the valve, and
allows the water to escape; and when the float-stone
again falls the valve is closed, thus preventing the
escape of the steam admitted into the box with the
condensed water.
In the heater the sugar is raised to 180", or that
best adapted to the hardening and completing the
formation of the crystals. During the heating the
sugar is stirred with wooden cars to prevent granula-
tion: it is ladled or run out into buckets or scoops,
and hence poured into moulds, or small cones, F or B,
Fig. 2107: the hole at the bottom of each cone is
plugged with paper, which is not removed until the
, morning after the
day on which the
moulds are filled.
The mould-room
is kept at the tem-
perature of 100°
for 3 or a days,
during which time
the sugar under-
goes the process
of liquor'z'azg: this
consists in pour-
ing on the top of
MOULDS Ari) TREA'CLEJAR. the moulds a SO_
lution of pure. sugar, which percolates through and
carries with it the small quantity of colouring matter
not previously removed. The drainings are collected
in pots or treacle-jars, T, Fig. 2107, which support‘ the



moulds, and are boiled down with other refuse of the
sugar-house into an inferior sugar. A'separat‘e pot
for each mould is not to be commended,‘ for if “the
pots are not well washed out there 7is a'liability to
fermentation, or smear, as -it is called, and this will
spread through the whole establishment with astonish-
ing rapidity, and when once formed, is difficult to era-
dicate. We have ‘heard of a sugar-refiner who had
to work up the whole of his stock twice before this
'evil could be got rid of. The use of pots is, in many
cases, superseded by supporting the vmoulds in frames,
as in_,_Fig. 2101, and allowing them to drain into
‘gutters or false floors of thin sheet-copper, sloping
~the manufactpre of sugar.

towards a centre constructed under the main floor,
where the syrup is conveyed by copper pipes to a
cistern. It has been proposed to expedite the drain-
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Fig. 2108. M-oULns IN FRAMES.
ing of the moulds by connecting their nozzles with a
pipe communicating with an air-pump ; but in such
an arrangement the sugar would be liable to be drawn
through the perforations with the syrup. Several
other plans on the vacuum principle have also been
proposed.
When the sugar is properly drained it is taken out of
the moulds in the form of loaves, which are trimmed
to shape, placed in a stove or hot room of the tem-
perature of 130° to 14.00, and when the moisture
has evaporated, they are fit for the market. The sugar
thus obtained is half the weight of that let down into
the heater from the vacuum-pan; the remainder con—
sisting of moisture or drainings. A very small pro-
portion of the syrup that drains away consists of
uncrystallizable sugar or treacle in which all the im-
purities of the loaf are accumulated. If the improved
operations have been well conducted the produce is
equal to refined sugar, and there is no practical reason
why perfectly white sugar should not be produced
from the canes at one operation. The sugar, as it
comes direct from the canes, contains only 1'5 per cent.
of impurities, whereas the sugar-refiners in England
have to operate on a material considerably deteriorated
by previous mismanagement. Fiscal regulations have
hitherto interfered with colonial improvement, a larger
duty having been imposed on sugar above a certain
standard, thus actually discouraging the production
of white sugar at its natural seat of manufacture, and
encouraging slovenly and had work. In the islands
of Java and Cuba, where the best machinery has been
introduced, from 30 to 4.0 per cent. is now saved in
the quantity of sugar produced, and its market value
is increased from 58. to 108. per cwt.
British Guiana is also a striking example of the
good results of improved processes and machinery in
Some years ago it was
feared that this colony must have ceased to grow
sugar in consequence of not being able to compete
with Barbados and Antigua, where the new ma.-
chinery was in full play. No sooner, however, did
Antigua join in the march of improvement, than her
fortunes began to change. In 1851 the quantity of
sugar made with improved apparatus amounted to
7,170 ‘hhds., or upwards of %th of the produce of the
colony. In 1852 the ‘quantity was 10,380 hhds., and
in 1853 the quantity is expected to be 13,000 or
14,000 hhds., or as large a proportion of refined sugar
to the quantity manufactured as in the United States
SUGART
785
where no duties are levied. What is wanted to com-
plete the improvements which are now going on in
our colonies is one uniform rate of duty on sugars,
without any reference to their fineness; and it has
been proposed to reduce the duties to the uniform
rate of 108. per cwt., a proposition which will probably
be adopted. In anticipation of this result a joint-
stock company has been formed in Barbados, with a
capital of d0,000l. ; and they propose to purchase the
canes of the small planters, and manufacture sugar on
a large scale with all the modern improvements. A
great saving is thus expected to arise from the
separation of the agricultural from the manufacturing
part of the trade. Jamaica is said to have been
behindhand in the adoption of improved machinery,
but that the vacuum-pan is now becoming general
on all the plantations. It is stated that in several
parts of the West Indies, by employing the cane trash
as a manure instead of burning it as fuel, with the
addition also of a moderate quantity of guano, the
yield of the cane has doubled and even trebled, 41 tons
of sugar per acre having been made even under the
present wasteful system.1 The planters are now also
becoming aware of the advantage of packing up a
dry crystalline grain instead of sugar made wet and
spongy by the deliquescent molasses, which, gradually
oozing out of the casks, washes the sugar away with
it, and is pumped out of the hold of the vessel into
the sea.
Sncrrou IV.——Mauuracrunn or Rnrinnn
Susan.
The defects in the manufacture of raw sugar led
to the contrivance of certain methods of separating
the colouring matter and the melasses from the
crystalline portion, and introduced the art of the
sugar-refiner, which has long been an important
branch of industry in Great Britain. It is evident
that the refining of sugar in this country instead
of the colonies must be disadvantageous in many
respects, for the sugar has to be redissolved in
water, which must be again evaporated, and during
this process the sugar is again exposed to the risk of
deterioration, and a certain portion of crystalline
sugar destroyed. There has been indeed a less
amount of loss since the sugar refiners have adopted
the improved apparatus and processes of the beet-root
sugar factories. Previous to this the only purifying
material employed was animal albumen in the form of
bullock’s blood, which of course formed a new source
of deterioration in the sugar; while so little was
known as to the science of the operation, that the
amount of success depended chiefly on the skill of
the workman. Since the introduction of animal
charcoal and steam heat the operation of refining has
been conducted with the precision of a scientific

(l) The absence of nitrogenous manures in the colonies has led
to their extensive importation from Europe, such as dried blood,
flesh and fish refuse, shreds of woollen cloth, animal black, 8zc.
The use of blood as a manure formerly attracted the rats in large
numbers, and not only was the blood consumed but the roots of’
the canes were injured. The ravages of these animals were pre
vented by mixing charcoal dust and fat with the blood.
VOL. II.

process. There is, however, this additional objection,
that the raw material is const. ntly changing in quality,
and there is no certain and ready means of testing
the amount of pure uncrystallized sugar in raw cane
sugar. The relative amount of colouring matter may
be ascertained by making experiments on a small
scale with animal charcoal. The optical test may
also be adopted. It must be constantly borne in
mind that the great object of all improvements in
the manufacture, is the production of a better quality
of raw sugar. The colonial manufacturer will pro-
bably never be able to produce refined sugar at once
from the juice, but this is the standard of perfection
which he should endeavour to attain as closely as
possible.
The raw sugar from the West Indies, America, and
the East Indies is chiefly imported in cases; from
Jamaica, Domingo, and St. Oroix in hogsheads; from
Manilla and Mauritius in double sacks plaited or
woven from the leaves of reeds. The quality varies
in all degrees, from white Havannah, almost equal to
loaf sugar, to the dark brown, moist, sticky, and
smeary characters of the worst varieties. The more
coarsely granular, the harder, drier and whiter, the
greater is the value of the sugar, and the better is it
adapted to bear carriage. _
The first operation at the refiner’s is to empty the
cases or hogsheads on the clean floor. A quantity‘bf
sugar adheres to the staves, which is large in propor-
tion as the sugar is sticky. It is loosened and
removed by means of steam, for which purpose the
hogshead is inverted over an arched copper surface
in the form of a flat inverted boiler, in the centre of
which is a steam jet pipe, and the edge is turned up
to form a channel. In a few minutes the steam con-
denses on the sides of the cask, and becomes saturated
with sugar; the solution collects in the channel and
flows into the pan in which the great bulk of sugar is
dissolved. The sugar is first passed through a sieve
to remove lumps, and a sufficient quantity of wateiiis
added to the melting—pan to make up about 30 per
cent. including that from the hogsheads,‘ and steam
is applied to dissolve the sugar as quickly as possible,
for which purpose a perforated pipe is fixed at the
bottom of the pan, and when the steam is turned on
it blows up through the water and completes the
solution; hence these pans are sometimes called blow-
24p cisterns? The concentrated solution, or melting as
it is called, is allowed to flow into the clarifying-pan,
while the melting-pan is directly supplied with a
fresh charge, so that one melting-pan or blow-up
cistern is sufiicient. While being dissolved in this
pan, a small portion of blood and some lime water are
added for the purpose of clarifying the solution and
neutralizing the acid. The solution is agitated by a
mechanical stirrer, or by 2 or 3 men with cars. Only
about 12— per cent. of blood is used, and its action is
materially assisted by 3, d or 6 per cent. of ground

(2) Mr. Finzel has patented aplan for melting or blowing up in
vacuo. The advantages are, that exposure to air and heat being
avoided none of the sugar is converted into melasses, and the
solution is efi'ected with great rapidity.
3n
2786
SUGAR.
animal charcoal.1 The blood must'be uniformly mixed
first with a small quantity of saccharine liquor, and
this is stirred into the pan, the temperature being
kept below 168°, or that at which albumen coagulates;



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l-‘igs. 2109. BLOW-UP CISTERNS.
but this low temperature is maintained only for a few
minutes, when, to prevent the decomposition of the
blood, steam is fully admitted, and the solution rapidly
urged to the boiling point. The use of the albumen
dispersed throughout the solution is to entangle and
so collect the minute mechanical impurities, and then,
by its coagulation, it forms into large connected
‘flocks, easily separable by strainers. It forms with
the charcoal a thick compact scum, quite distinct
from the clear liquor below which has been partially
decoloured by the action of the charcoal. It still,
however, contains suspended impurities coated with
albumen, and hence the liquor is passed through a
_ a.
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Fig. 2110. BAG- FILTERS.
bag filter, Fig.2.110, or‘still better, through bags which
filter from the outer into the inner surface, an arrange-

ment. which allows the filters to be more easily
cleaned, and their wear is not so rapid. In the
interior of these bags basket work is placed to keep
the sides from collapsing. The filtration into these









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Fig. 2111.
CHARCQAL FILTERS.
bags is so rapid that an ordinary charge of 7 cwt. in
the melting-pan can be passed through in from 15 to
20 minutes. The- filtered liquor is collected in a
cistern, whence it is passed through the charcoal
filters, which in the course of 15 to 20 hours dis-
colour a quantity of syrup containing st times as much
sugar as there is charcoal in the filters. The syrup,
now called liquor, is collected in another reservoir
which supplies the boiler.
The boiling‘ is conducted either in open pans heated
by steam, or, what is by far the more common, in
vacuum-pans: the liquor is evaporated to the density
of 412° or 43° 13., at a temperature varying from 2300
to nearly 24,00. In fact, the liquor is so concentrated
that the sugar is only held in solution by the high
temperature, so that, on cooling, a rapid crystalliza-
tion takes place, which produces that uniform fine
grain such as is required in loaf-sugar. It was for-
merly the practice to produce a slow crystallization by
evaporating the water in a hot chamber, instead of a
rapid crystallization by simply lowering the tempera-
ture of the concentrated syrup. The former practice
was slow, and required a good deal of space. But in
order to produce this fine grain, or irregular con-
glomeration of crystals, the liquor must be poured
into the moulds at a certain temperature, just when
the crystals have begun to form; and as the liquor
leaves the vacuum-pan at too low a temperature for
the purpose, it is heated up in a vessel furnished with
a false bottom for the admission of steam, which is
again the convenient source of heat, and then cooled
to the granulat-ing point in vessels capable of holding
the entire quantity of liquor boiled in a day. As the
temperature falls, the formation of crystals of too
large a size is prevented by stirring: at a certain
fixed temperature the syrup is poured into the
moulds, which, as usual, are of the funnel or sugar-
loaf form ; for the purpose of assisting the separation

(1) The French prepare cakes of this mixture in a dried form,
so as to be ready for use when required.
a
of the mother liquor, there is a hole in the . point-
SUGAR.
787
of each mould, which is at first closed up. The larger
the bulk of syrup the slower is the cooling, and the
more regular the crystallization. For bad syrups,
which crystallize with greater difficulty, large bastard
moulds B, Fig. 2107, are used; but the smaller ones
I‘ are employed with syrups which are inclined to
produce too coarse a grain. The moulds were
formerly made of porous clay, which, however, ab-
sorbed much syrup, and occasioned trouble in clean-
ing: iron was, therefore, substituted: the iron
moulds are coated either with varnish or glaze, or
painted with white lead paint. They are arranged
in rows in the crystallizing—rooms in treaclc—jars T,
Fig. 2107, or on wooden supports, under which the
pots are placed. They are filled with syrup from








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My. 2112. FILLING 'rnn MouLns.
the coolers by means of large copper scoops, by a
number of men who pass rapidly to and fro, filling
and emptying their scoops, and they so contrive as
not to fill any mould at once, but to let each mould
receive syrup from different layers of liquor in the
cooler. They are filled on the lowest floor, and are
raised to the upper floors either by manual labour, or


" i ‘ ill-fill! ' “drill “at”
Fig. 2113. mourn CARRIER.
by a mould carrier or hoist passing up through the
house from top to bottom, the construction of which
will be understood by referring to Fig. 2113. As the

sugar tends to crystallize first at the sides, especially
if they are rough, and also to form large crystals on
the surface, the syrup is stirred up in the moulds
with a wooden spatula or knife to detach it from the
sides, and this process is repeated after half an hour.
The crystals thus become equally diffused through
the thick syrup, and afford points for a uniform crys—
tallization, which is complete in from 14: to 18 days.
In this way a compact net-work of small crystals is
formed, the meshes being filled up with the mother
liquor or saturated solution. This is impure in pro—
portion as the crystals are pure, but being viscid it
drains off with difficulty, even although assisted by
the warm atmosphere of the room, which is main-
tained at 7 5° and upwards. The plugs are removed
from the points of the moulds, and they are left to
drain for 2% hours. When the running abates the
loaves are loosened by inverting the mould and de—
taching the sugar: the syrup then drains off. more
freely. The green syrup thus separated is collected
or allowed to run together from a connected system
of gutters, and is removed every day; or the moulds
are arranged over wooden pipes lined with zinc, with
openings in the upper surface to catch the drippings.
In about A days or more the melasses are tolerably
well separated, except at the point of the loaf, which
still retains a little colour. The loaves are now
taken out of the moulds; the brown points are cut
off for remelting, and the loaves are trimmed and
dried.
The above process does not afford loaf-sugar of
very good white colour, or of a dry and firm texture:
a little of the coloured syrup is still entangled in the
interstices of the crystals; so that instead of, or in
addition to, the above process, that of slaying is
resorted to. This is a method of washing out the
remains of the coloured syrup by the following con-
trivance:--White pottery clay, not so fat as to
retain a very large quantity 'of water, is washed, in
order to separate the soluble ingredients, and then
placed on the sugar, while still in the moulds, in the
form of a uniform thin paste. Before the application
of the clay each loaf is removed from the mould, the
solid crust formed at the point is removed, and the
upper layer at the base is loosened and scooped out,
in order to form a cavity in the centre for the recep-
tion of the clay paste, which is put on 1 lb. at a time
in a layer about 41 lines thick. The action is as fol—
lows :—-The water from the clay drives the melasses
before it, and soon becomes converted into a satu—
rated solution of pure sugar by dissolving some of
the crystals. The other portions of the water form
still purer solutions, and they all sink through the
leaf, expelling the mother liquor, and the brown
colour descending towards the point gradually dis-
appears. In this way the crystalline net-work of
nearly pure sugar in the mould becomes impregnated
with a pure solution of sugar, which, in drying,
cements the crystals together, and imparts the re-
quisite solidity to the loaf. The clay is generally
removed once during the operation, and the syrup
which drains off is termed clayecl syrup.
3 n 2
‘.788
SUGAR.
The use of clay is now superseded by a pure satu-
rated solution of sugar: it has the advantage of not
dissolving any of the crystals of the loaf (because it is
already saturated at the temperature of the mould),
and it gets rid of the trouble and inconvenience
attending the use of clay; it leaves a pure surface,
and introduces no foreign ingredient into the loaf.
The saturated solution is poured in at the top 'of the
mould, left for some time, and when it is observed to
trickle slowly from the point, the moulds are inverted
for a short time that the residue of the clay-syrup
collected in the apex may be difiused through the loaf,
and give it a uniform colour: or the point may be
knocked off, and a new top be afterwards produced,
by turning it between crooked knives. The loaves
are separated from the moulds by a blow on the edge,
and are again placed with their points down, that the
syrup between the surface of the loaf and the side of
the mould may drain off. This done, they are placed
upright and covered with the mould until ready to be
removed for drying, first, at the ordinary temperature
of the room for a day, and then in a drying chamber,
at 77°, which is gradually raised to 122°. The sugar
thus produced is of the first quality. The secondary
products, consisting of the various syrups, are added
to water for the purpose of dissolving the next charge
of raw sugar, or they are mostly treated alone for the
different varieties of bastard sugar. The last portions
retain so large aquantity of syrup, that they are too soft
for 2041/, and are sold as moist sugar. The inferior
syrups are much more slowly cooled : they are run into
bastard moulds B, Fig. 2107, of 1 cwt. each, and are
crystallized at a higher temperature in proportion as
the sugar is less pure. The first quality mould contains
about 30 lbs. weight of the granulated mass, and from
this about 10 lbs. of green syrup will drain 0E, leaving
20 lbs. of wet sugar, which, by drying without claying,
are reduced to 17 lbs., but if clayed to lllbs., but
this is sugar of the first quality. In a bastard mould
60 lbs. of granulated sugar of the second quality, 25 lbs.
of melasses will drop from it, leaving 35lbs. of un-
clayed moist sugar, or 32 lbs. when dry, which, after
claying and drying, produces 17 lbs. as the market-
able product. The time required, from the melting
of the raw sugar to the completion of the dry loaf,
is from 35 to 40 days, and longer for the inferior
qualities.
Many attempts have been made to shorten the time
required for refining, or, in other words, to expel more
rapidly the melasses from between the crystals. The
temperature of the rooms has been increased: the
pressure of the atmosphere‘has been called into play,
by placing the point of the mould over a long
column of melasses, so as to form a Torricellian
vacuum which, from the great density of treacle, may
be had with a vertical height of about 23 feet, and
into this vacuum the melasses is expelled from the
mould by atmospheric pressure. Derosne has pro-
posed, instead of the saturated solution of sugar
in the claying process, to employ alcohol of the density
of 33° or 34:“, which dissolves the syrup readily,
while the crystals are not much aifected by it. The

plan is quite successful, and is expeditious, 6 days
only being required instead of from 35 to 40: but
the danger of fire and the high price of alcohol
in this country, are suflicient objections to its adop-
tion.
Another chemical mode of refining has been pro-
posed by Dr. Scoffern, which, if it could be carried
out without danger, would be of great value, since
the use of animal charcoal and of filtration would be
rendered unnecessary. The proposal is to separate
all the colouring and foreign matter in the saccharine
juice by means of a solution of basic acetate of lead,
the oxide of lead in which combines with these mat-
ters, and precipitates them in an insoluble form; the
excess of lead-salt employed by saturating the saccha-
rine solution, after the separation of the lead precipi-
tate, with sulphurous acid gas, which produces with
the lead an insoluble sulphite of lead, the excess of
gas being removed by simple boiling. The above in
genious process is not new. The late Professor
Daniell, who was connected in early life with the
sugar-refining trade, discovered this, or an analogous
process, with acetate of lead; but being aware of its
danger he kept it in his own hands. For many years
after he became professor of chemistry at King’s
College, he was in the habit of attending certain
sugar refineries every week, where he gave out the
proper quantity of acetate of lead (which at other
times he kept under lock and key), and when the
sugar had been refined by its means, he again at
tended to test the syrup, to be quite sure that the
whole of the poisonous salt had been removed. In
the hands of such a man there could of course be no
danger to the public from the use of a poisonous salt
as a means to an end; but in careless or unskilful
hands it might lead to disastrous results: hence the
process is not to be recommended.1
It has been proposed to separate the melasses or
noncrystalline portion of the sugar from the crystal-
line, by the action of centrifugal force, for which pur-
pose the sugar, properly prepared for the purpose, is
put into a cylinder of wire gauze and rapidly rotated,
when the sugar being driven against the sides of
the drum, the melasses escape through the meshes,
and are carried off through a cock in the outer case.
In this way the crystals may be brought to any degree

(1) In the report of the British Association for the advance-
ment of Science for the year 1850 is a communication from
Dr. Scofi‘ern, from which it appears that on the southern coast of
Spain, in a region limited by Almeria on the east and Malaga on
the west, bounded on the north by mountain ranges, and on the
south by the Mediterranean, is a tract of land in which the date-
palm, indigo, cotton, and sugar-cane flourish with vigour. “ The
sugar-cane first introduced by the Arab conquerors is not only
consumed in large quantities as a dessert, but also gives rise to a
considerable manufacture of raw and refined sugar.” Dr. Scoifern
has introduced his process into this district, and although ope-
rating with the old and imperfect apparatus, he describes it as
being successful; “ sulphurous acid being an agent most antago-
nistic to fermentation,” and “the sulphite of lead being most
easily removed, and were it to remain, no injury could supervene,
inasmuch as this agent is as harmless as chalk.” In the discus-
sion that followed, Professor Christison stated, that caution was
necessary in accepting as a fact the statement, that the presence of
a small quantity of sulphite of lead in sugar would not prove in-
jurious to health.
SUGAR.
789
of whiteness, ‘but cannot of course be made into
I loaves. The arrangement
of the apparatus is shown
in Fig. 2114!, in which n
is the drum or cylinder,
which may be of sheet
metal or wire gauze: I,
‘an external casing of
cast-iron; s, the shaft to
which the drum is at-
tached, and is driven by
e the usual gearing G with
less than that of l-horse.
- Z The whole machine is 4-;-
Fig- 2114- feet in diameter; it con-
tains about 2 cwt. of sugar at each charge, which is
refined in about 8 minutes.
Mr. Bessemer has patented a variety of machines
and improved processes connected with the manufac-
ture of sugar: one is for a centrifugal filtering ma—
chine for separating fragments of cane, &c. from the
juice after being expressed from the canes, and also
the coagulated matters after defecation. The purified
juice is also evaporated by a centrifugal evaporator,
and the result of a number of most ingenious arrange-
ments, is the production of a beautiful highly crystal-
line grain, or what is known in the market as eras/zed
sugar; but it is stated that it does not realize the
extra price required to compensate for the smaller
quantity produced.
The manufacture of sugar-carzrlg'may be regarded
as a branch of the refiner’s art. The large crystals of
sugar, which pass by this name, are prepared from a
syrup clarified with aless quantity of charcoal-powder
than is usual, and not passed through the filter. a The
crystals, which are coloured, inclose a certain portion
of non-crystalline sugar. If the candy is required for
the sake of its solvent action on the mucous mem-
brane of the throat, it should not “be prepared from
clarified or clayed sugar. To increase its mucilagi-
nous and sticky properties it should, after clarification
with white of egg, be boiled over an open fire and not
in vacuo ; and for the darker kinds of sugar-candy a
higher temperature should be employed than for the
lighter. The syrup is set to crystallize in a copper
vessel with smooth sides, and contracted towards the
bottom that the crystals may be easily removed. At
the sides are several small rows of holes at equal
heights, through which strings are passed which serve
as nuclei to the crystals. The copper is filled up
above the strings, and is then placed in a drying chamber
at the temperature of from 104° to 122°. As the
syrup cools and evaporates, solid crystals are slowly
formed, partly on the surface, but chiefly on the
strings and the sides. The crystals on the surface
are frequently broken up. In 6 or 8 days the crys-
tallization is complete; the vessel is inverted, the
syrup drains off, and when the dropping ceases the
crystals are removed and dried.
A description of sugar, called stamped sugar, is
prepared from the inferior qualities, generally lump,


in such a manner as to have the shape and appear-
ance of first quality refined. Moist soft lump sugar
is grated or mechanically divided, and the flour passed
through a sieve: while still moist it is stamped in
layers into a first quality mould, from which it is
immediately removed and dried.1
i!
Snorron V.——Mnnnrno'runn or BEET-ROOT Susan.
A short notice of the cultivation of beet-root is
given under the head BEET. There are a large num-
ber of varieties of this plant, of which the following
have been used in sugar factories; viz. I. The large
field beet, the rlz'sezfle of the ,French, and the mangel
wurzel of the Germans : the flesh and skin are white,
as are also the leaf-stalks: the bulb is almost cglz'rz-
clrz'cal, and protrudes very much out of the ground,
sometimes as much as 15 inches, while 4: or 5 only
are covered with soil: this is the largest of all the
varieties, single bulbs weighing 25 lbs. and upwards
each. A bulb of as lbs. is noticed by Knapp. This
large size is not to be commended, since the watery
character of the bulb increases with the weight. The
juice rarely exceeds 6° Baumé in density; there is a
sub-variety of a reddish colour, the cross section of
which exhibits an alternation of white and rose co—
loured rings. It is known as Long recl mangels. The
blood-red garden beet is regarded as the link between
the first and second varieties. II. The second group
is represented by the white Silesz'cm beet: it has a
somewhat pear-shaped form, white flesh and skin, and
occasionally rose-red rings in the flesh; it is smaller
than the preceding varieties, the largest roots gene-
rally averaging 5 lbs.; the juice is pure; it abounds
in sugar, and is more easily operated on by the sugar
manufacturer than the other varieties, on account of
the absence of salts and other ingredients which exert
an injurious action on the sugar’ in boiling, and di-
minish the value of the produce or impede the process.
It is hard and resists putrefaction, so that the bulb
can be kept for a time with but little loss. When
fully ripe ' and properly cultivated the juice usually
averages 7° of Baumé, but it often exceeds 8°, and
has been known to be much higher. There are 3
chief varieties of the White Silesian, distinguished by
the colour of a ring presented by a cross section of
the crown close to the bulb. These are—l. The
collei rose, with a rose-red ring. 2. The collar‘ earl,
with a green ring. 3. The collet jazme, which has a
yellow ring. The spindle or pear-shaped beet of the
second group is linked to the third by the variety
called the Quezllz'rzburg leer‘. Its form is between the
pear and spindle shape; the skin is rose-red, the flesh
white, and somewhat softer than the Silesian: the
average density of its juice is about 7° E. III. The
type of the group of the third form, or glolular, is
the gellozo globe rzarzgel wzlrzel, or Caslelrzauclarg beet.
It is pear-shaped, approaching to globular; the skin
and flesh are yellow, sometimes passing into orange;
leaf-stalks yellowish green; the flesh soft and juicy;

( 1) We have to express our acknowledgments to Messrs. Fairrie,
of Whitechapel, for information on the subject of refining, and
for permission to take sketches for our engravings.
790
SUGAR. I
and the‘ density'of its juice from 5° to 7° B. It
grows to a much larger size than the Silesian beet.
Four sub-varieties of it have been distinguished; one
of which is the w/zz't‘e globe beet. The Siberian beet
belongs to the third group; it is of a flattened pear-
shape, spread out almost. like a plate; the flesh is
white, or occasionally rose-red; the leaf-stalk is white;
this variety is softer than the Silesian ; ‘it. yields'more
juice, but of a lower specific gravity. The bulb grows
nearly altogether out of the soil, which is a disadvan-
tage, since the parts of a bulb which are exposed to
the full action of the ‘sun contain less sugar than that
portion which is covered by the soil.
All the varieties of beet tend to change their colour,
and to develop a red colour in the skin, and a slight
rose tinge in the flesh, especially the white and yellow
varieties. They do not appear to differ in chemical
composition.- They all contain sugar, and may be
used in its manufacture; but the variety most em-
ployed for the purpose is the White‘ Silesia”, or sugar
beat, the collet rose beipg most prized as containing
the richest and purest juice. The Quedlinburg beet
is preferred in North Germany: it is thought to keep
better than the Silesian, and its juice to alter less by
exposure to the air.
A section of the beet perpendicular to its axis
exhibits a series of concentric rings: first there is the
epidermic tissue, consisting of from 41 to 6 layers of
cells, composed principally of cellulose, and containing
a great part of the silica of the root :. it also abounds
in nitrogen. Immediately under the epidermic layer
comes the herbaceous tissue, in which are principally
contained the colouring principle, an essential oil, and
one or two peculiar substances. The true saccharine
part succeeds this: 'it extends to the centre, and con-
sists of alternate layers of vascular and cellular tissue.
The vascular tissue. is doubled into several distinct
bundles, surrounded by cells forming the whitest
zones, which are most voluminous in good varieties of
beet, and contain the largest amount of sugar. The
leaf~stalks take root somewhat deeply in the bulb, and
form what is called the heart; it is of a greenish
colour, and abounds in fibrous vessels, containing
very little sugar, but a large proportion of salts, espe-
cially nitrates. The cells sometimes contain starch,
as inthe early autumn.1 The whole of the. sugar in
a liquid form is found in the cellular tissue, and in
much greater quantity in the cylindroidal cells sur-
rounding the fibrous tissue; the latter contains no
sugar, but frequently salts in a crystalline form.
Crystals of sugar also occupy’ a number of cells. in
roots where the juice is of high density, such as. 12°
to 1%’ B. The seat of the nitrogenous substance,
which acts so rapidly on the juice when pressed, is
supposed by Messrs. Sullivan and Gages to be in the

(1) This fact appears to have been first ascertained by Messrs.
Sullivan 8: Gages, and is stated in their “ Report on the compo-
sition of "White Silesian Beet grown in Ireland, in- 1851, considered
in referen cc to its employment for the Manufacture of Beet Sugar.”
This Report forms an Appendix to Sir Robert Kane's “Report of
Inquiry into the Composition and Cultivation of the Sugar Beet
in Ireland, and its application to the Manufacture of Sugar.”
Dublin, 1852. » ’

fibrous tissue; “for when a thin slice of beet, cut
perpendicular to the axis, is exposed to warm air, the
concentric rings of the vascular tissue first become
black.” The whole of the sugar in the beet is crys-
tallizable cane-sugar; neither grape sugar nor man-
nite exists in the beet, unless it has undergone some
change. The per-centage of sugar gradually increases
until the beet is fully ripe, and it has been shown
‘that by good cultivation the amount of. sugar which
the beet may contain is nearly equal to that of the
sugar-cane. As soon as the flower-stalk begins to
form, the per-centage of sugar declines, and when the
seed is formed it is reduced to almost nothing.
The composition of the beeteroot is very complex.
It contains on an average 10 per cent. of sugar, 3 of
pectine, soluble salts, &c., and 83 per cent. of water;
thus making 96 of juice, the remaining 45 parts con—
sisting of albumen, woody fibre, and insoluble salts.
The following~ is the analysis of some beet-root
grown at Giessen, first in the fresh state, and then
after having been dried :—
Prcsh. Dry.
Albuminous matter 204 11-5
Sugar 12-26 688
Cellulose and other nitrogenous substances .. 2'56 14'6
Mineral substances.................................... 0'89 5'0
82-25 .... ——
100100 99 9
The nice of the beet-root ferments like that of the
sugar-cane: it generally undergoes the mucilaginous
fermentation: mannite is produced at the expense of
sugar, and a kind of mucus is formed which is preci-
pitated by alcohol, and resembles gum-arabic in ap-
pearance and composition.
M. Payen gives the following as the results of his
examination of the beet :--
83'5
Cellulose 0'8
Albumen, caseine and other nitrogenous substances.... 1'5
Malic acid, gummy substance, fatty substance, aromatic
and colouring principles, essential oil, chlorophyle,
asparamide; oxalate and phosphate of lime, phos-
phate of magnesia, muriate of ammonia; silicate, ni-
trate, sulphate and oxalate of potash; oxalate of
soda; chloride of sodium and of potassium ; pectates
and pectinates of lime, of potash, and of soda; sul-
phur, silica, oxide of iron, 3'7
.—
100-0
It has been shown by practical experiment and’
chemical analysis, that there is no material difference
in beet grown over a region extending from the
Atlantic Ocean to the Caspian Sea, and from the
Mediterranean Sea nearly to the Arctic Ocean.
Beet will grow upon all kinds of soil; but a light
rich loam, rather inclining to clayey than to sandy, is
best adapted. to produce abundant crops of good
quality. The soil must be well worked and to a con-
siderable depth, that the bulb may have room to
expand, and not have to throw out too many roots in
search of food. Bich nitrogenous manure, such as
farmyard manure, guano, &c. should not be applied
to the land immediately before sowing; but should
be applied with the previous crop or during the pre-
ceding autumn, or be put on as a winter compost;
SUGAR.
791
Unless these precautions be used the juice of the
beet will be rendered impure, and the proportion of
readily fermenting azotised materials be increased.
Sir Robert Kane, in the oflicial Report already re-
ferred to, thus refers to the proposal to introduce the
manufacture of beet-root sugar into Ireland :—-“ It is
certain that by no process as yet employed are the
manufacturers able to extract absolutely all the sugar
really contained in the beet in its crystallizable form ;
yet this is the object to which manufacturers should
aspire, and towards which almost every day a closer
approximation is made: and it is now well established
that by the application of the most perfect mechanical
arrangements, and the adoption of the improved che-
mical processes of refining, the quantity of sugar
extracted in a marketable form approaches closely to
that really existing in the beet, while the proportion
of melasses formed is but trifling. In considering,
therefore, the position of the manufacture as to Ire-
land, it must be assumed that the manufacture should
be conducted with the most perfect means, most
accurate knowledge, with careful economy, and judi-
cious business management; for, should those con—
ditions be not fulfilled, the manufacture would
necessarily fail to succeed here, as it would fail else-
where from the like causes ; and the country or the
period would be stigmatised as unsuited or improper
for the manufacture, when the fault really lay with the
ignorance or inattention of the individuals who had
taken up an occupation for which they did not possess
the necessary qualifications.” The establishment of
the manufacture in Ireland appears to Sir R. Kane
to be “ eminently calculated to be of service, not only
as creating a new and extensive source of manufac-
turing employment, but also that as the material used
can only be profitably obtained by means of improved
agriculture, and that an important element in the
profits of the manufacture would be the careful eco-
nomy of the scums and pulp, either as manures or as
food for cattle, the manufacturers of beet-root sugar
should exercise a powerful influence on the agricul—
ture of their districts, inducing a greater variety of
cultivation, a more thorough preparation of the soil,
and a more careful economy of manures ; and that in
this way, even should the manufacturing speculation
become hereafter, by improvement in the management
of the colonial-sugar industry, or by any other cause,
less probably successful than it now appears to be,
there should still have been conferred on Ireland a
great advantage in the improved practice of green-
crop husbandry, which would be certain to remain.”
The beet-root may be kept for some months in
silos, prepared in the same manner and with the same
precautions as those used for keeping potatoes [see
STARCH] ; but there is always danger of the sugar
passing into the non-crystalline variety. When the
roots are about to be used, the bruised, decayed, and
mouldy parts must be carefully removed, or the juice
will be very liable to ferment and spoil. The leaves
and the root are of course removed as soon as the
plant is gathered.
The first operation in the manufacture is wasting

fine talus, to get rid of sand and earth : this operation
is usually carried on in a drum, formed of laths or
bars of wood arranged parallel to a nearly horizontal
axis, and partly immersed in water. On causing the
drum to revolve slowly the bulbs scour each other,
and the dirt passes through the open spaces. The
axis of the drum is somewhat inclined, so that the
bulbs being fed in at a hopper situated at the upper
end of the drum pass slowly down to the lower end,
where they are raised by a scoop and thrown upon
a lattice frame.
The bulbs are now ready for rasping, the object of
which is to tear open the cells in which the saccharine
juice is imprisoned, and to reduce the bulbs to pulp
ready for the press. The rasping or grating machine
is a hollow cylinder or drum, the surface of which is
thickly studded with teeth, against which the bulbs
are pressed while the drum rotates ; the‘ action being
very similar to the rasping machine which reduces
potatoes to pulp, as shown in the steel engraving
which accompanies Srxncn. As in the case of that
machine, a stream of water plays upon the teeth, to
prevent them from becoming clogged with the pulp.
The hopper is in 2 divisions, both in the same plane,
and one is filled while the other is feeding the drum,
which makes from 7 00 to 800 revolutions per minute,
and reduces from 250 to 300 cwt. of bulbs into pulp
daily. The drum is covered with a lid, to prevent the
pulp from being thrown about, a cistern below being
provided for its reception.
The third operation is the pressing, which is carried
on simultaneously with the rasping, on account of the
great tendency of the juice to spoil. The pulp is
placed in bags of woollen cloth or of stout unbleached
hemp of open texture, which are evenly arranged on
the bed of a hydrostatic press; each bag forms a layer
about 2 inches thick; the open end is turned in, and
a metal plate, or a hurdle of plaited willow twigs,1
placed upon it; another bag of pulp is then placed
on, with the turned-in end in the opposite direction
to the first; then another hurdle, and so on. Two
presses are worked for one rasping machine, and one
is emptied while the other is at work. The greater
portion of the juice is expressed in about 10 minutes;
another portion in another 15 minutes; while about
15 or 20 per cent. of juice remains in the pulp, a por—
tion of which is removed by immersing the sacks in
water containing , O‘ooth part of tannin in solution,—--
for the purpose of checking any tendency to fermen-
tation, when they swell up to their former bulk,—-and
pressing them again; or the sacks are exposed to a
jet of steam until it ceases to be condensed. Care
must, however, be taken not to boil the pulp, or it
cannot be pressed. The expressed juice is collected
in a gutter arranged round the press, and it flows
from an aperture through a pipe into a reservoir.
The tables on which the bags are filled has also a
gutter leading to the reservoirs, and in some factories
the first pressure is made on this table, by means of
a small hand-press, which expresses 30 to 4:0 per cent.

(1) The willow is first peeled and then boiled, in order to re-
move bitter and extractive matters.
792"
SUGAR.
l
of ' the juice; the more energetic pressure being
reserved for the hydrostatic press. The rasping ma-
chine and press must be kept perfectly clean, and
occasionally be washed with lime water.
The arrangement of the bags and hurdles, and the
intermittent nature of the process when the hydro-
static press is employed, have led to several ingenious
attempts to invent a constant and continuous press.
Pecqrleur’s press is of this kind. It consists of a
forcing-pump, which communicates the required
amount of pressure to the pulp, and straining-drums,
which’ separate it while under the influence of this
pressure into juice and lees. A copper funnel open-
ing: into the barrel of the pump, is kept constantly
fullof pulp, so that when the piston has attained its
highest ‘position, the whole space in the barrel below
it becomes filled with pulp, which is forced by the
downward motion of the piston through a valve, when
it is. discharged into a funnel-shaped vessel of cast-
ircn, and communicates its pressure to the mass of
pulp ‘with which the latter is filled. This funnel-
shaped vessel is closed on all sides, and the only outlet
for the pulp is through two hollow perforated cylin—
dens,~.surrounded by a cylinder of wire gauze: they
revolw‘re on their axis a few lines from each other, and
while the juice exudes through the sides of the rollers
andlfi'ows off by a pipe arranged for the purpose, the
fibres are thoroughly squeezed between the rollers,
andl are carried upwards by the motion of the drums,
andi discharged at the side by means of gutters. This
machine requires that the pulp be presented to it in
a particular state of division, which is not always
attainable, and even then it produces, by its peculiar
action, much froth and scum, which are of course
objectionable. Objections apply to other pressing
machines; and on the whole, the hydrostatic press is
the -- best form of press that has yet been adopted.
The objections to the above modes of rasping and
pressing are, that the waste pulp or husk still con-
tainsa. small proportion of sugar, and although it is
good l. for cattle when mixed with other kinds of
fodder, yet the manufacturer would prefer to obtain
alll the sugar from it. Besides this, the great expo-
sure to air during the rasping and pressing blackens
the "juice, which has been already reddened by the ni-
trogenous substances present, thus leading to the de-
composition and destruction of a portion of the sugar.
The presses also discharge into the juice not only all
the soluble matters, but also the finer particles of the
pul'pln'. For these reasons, attempts have been made-
to. obtain the juice by the process of maceration,
which has been conducted in a variety of ways ; but
the.“ essential steps are to cut the bulbs into thin
slices, and digest them repeatedly in warm water.
According to one plan, the slices are suspended in
baskets, with an equal weight of water at 167°, and
allowed to digest for half-an‘hour; a liquor is thus
obtained marking 41° on Baumé’s aerometer; the slices
are- taken out and fresh slices added, and the liquor
attains the density of 6° 13.; a third set of slices
raises it to 7 ° 13., and it is now fit for working. The
slices of beet that have once been used are repeatedly

macerated in water, and the liquor is used with fresh
slices instead of pure water. Various other ingenious
plans of maceration have been contrived, and carried
on for some time and then abandoned, the great objec-
tion being the large quantity of water thus introduced
into the juice, which has afterwards to be removed by
evaporation.
For some years past attempts have been made to
dry the beet-root as soon as it ‘is harvested, so as
to diminish its bulk about St per cent, leaving only
16 of dry matter; it could thus be transported to
very great distances; the beet-root sugar factories
could be worked during the whole of the year; and
a rich pure juicebe obtained ready for the clarifier
immediately. The expense of fuel is the great objec-
tion to the process, but the following plan is said to
have been adopted with some success. The beet-
roots having been pulled are washed, and then by
means of a turnip-cutting machine, cut up into small
cubes or parallelopipeds, which are dried upon floors
similar to those used for drying malt. [See BEER,
Fig. 106.] In order to extract the sugar from these
dried fragments, or cossettes, as they are named in
France, they are placed with 5 parts per 1,000 of
their weight of hydrate of lime, in large cylinders of
sheet-iron encased in wood to prevent loss of heat.
The cylinders are charged by a manhole in the upper
part of each, which can be closed at will. There is
also a pipe for introducing water and a pipe for
extracting the air by means of an air-pump. At
the lower part of each cylinder is a false perforated
bottom, and below this a pipe, which also passes
into the upper part of the next cylinder below.
The cylinders being charged with cossettes, water
from an upper reservoir at the boiling temperature
is allowed to flow upon the cossettes. After macera-
ting for some minutes, the liquor is passed from the
first into the second vessel; from the second into
the third, 'and so on to the fourteenth. In this
way the syrup in passing from one vessel to another,
increases in saccharine value, and the last macera-
tion is upon fresh cossettes. The resulting syrup is
of the density of 22° 13. It is drawn off and mixed
with a portion of the liquor- of the preceding vessel,
which takes its place until its density is 17°: it is
then heated to the boiling point, passed through the
charcoal filters and then into the vacuum-pan. The
complete apparatus which furnishes the syrup con-
sists not of 14 vessels as above indicated, but of 20;
14:, however, are only in actual use at one time,
41 being in course of emptying, cleaning, and recharg-
ing, and 2 being left charged in case of repairs
being wanted in those actually in use. A syrup
produced by the action of cold water is said to give
a juice ‘more readily worked for crystalline sugar
than when hot water is employed.‘
However the beet-root juice is obtained, it must be
raised almost as soon as obtained to the temperature
of 140° and upwards, to preserve it from fermentation.

(1) There is an extensive factory of beet-root sugar on the
above plan at Waghausel,‘ near Heidelberg. An English Beet
Sugar Company is about to adopt the plan in this country.
SUGAR.
793
The defecation is conducted by means of hydrate of
lime, the quantity of which varies with that of the
acids to be neutralized, from 3 to 6, 8 and 10 kilo-
grammes of lime to 1000 litres of juice. The heating
and defecation are conducted in such a vessel as Fig.
2099. To obtain a clear liquor an excess of lime
must be used, which was formerly saturated with
dilute sulphuric acid; but as this transforms the
crystallizable sugar into glucose, which is more inju-
rious than the lime, the use of alu'm has been intro-
duced; whereby sulphate of lime is formed, and the
alumina, set at liberty, assists the clarification.
Ammonia alum, not potash-alum must be used. It
has been proposed to employ in the clarification
pectic acid, which has no injurious action on the
sugar. The filtration is conducted in beds similar to
those shown in Fig. 2101, and the filtered liquor is,
rapidly evaporated to 25° B., in vessels similar to Fig.
2103 ; then filtered again, and passed into the vacuum-
pan.
In addition to Fig. 2103, there are various forms of
evaporators in use. That shown in Fig. 2115, called
“ the evaporating cone of Lembeck,” used by M.
Claes, of Lembeck, near Brussels, is said “to be effec—
tive. It consists of a double conical envelop, c 0,
about 16 feet high, heated by steam of the pressure
of 4. or 5 atmospheres. The interior of this hollow
cone receives the syrup from a reservoir s, which is fur—
nished With a ball-cock of; for the purpose of keeping



VI
9.
,6





.. __ ‘P
.7 %%
. C.
Fig. 2115. EVAPORATING cos a.
the level constant. The syrup flows from the stop-
cock 0’ into the funnel F, whence it is distributed by
6 or 8 openings over the interior surface of the cone.
The liquid in descending is divided and distributed by



means of 9 hollow conical segments, 1 . . . . 9' toothed
at the lower edge, and attached to an axis or stem aa, by
which they may all be withdrawn from the interior of
the large cone when the apparatus requires cleaning.
The exterior surface of the large cone also receives a
layer of the syrup to be evaporated, which is supplied
to it from the cistern s by a cock is, which feeds
the funnel BR, and from this funnel proceed 16
channels in the form of right angles, their openings
being within a few lines of the outer heated surface
of the great cone. The liquid in descending meets
the hollow conical vessels 1’ . . . . 9’, also toothed at
the lower edge for the purpose of redistributing the
liquor round the cone. At the bottom of the cone
the liquor falls into an annular reservoir R’, (the plan
of which is shown in the separate figure 11,) whence
it passes by the small channels l along the trough '1.‘
into a cistern V. By placing a second trough parallel
with T, the liquor from the interior and the exterior
of the large cone may be received into separate ves-
sels and the evaporative effect noted. If the concen-
tration be not satisfactory, the rate of efllux of the
syrup may be regulated by means of the cords K K’,
one of which acts upon the cock which supplies the
interior of the cone, and the other upon that which
supplies the exterior: the ends of the cords are at-
tached to the points of a needle 92 moving on a. dial,
which indicates the rate of discharge. Evaporating
cones of this kind frequently take the place of
vacuunnpans. '
There are various kinds of tests to which syrups are
subjected, for ascertaining when they are fit for the
purpose intended. They are at best but workman’s
tests, but seem to answer the required end. The
first (which has been already referred to in Sect. II.)
is called the string-lest, or prezwe azljllel, and consists
in taking a drop of syrup between the finger and
thumb, and suddenly removing them from each other :
if the syrup admit of being drawn out into an attenu-
ated thread, it is sufliciently concentrated for the
required purpose. If the thread breaks and forms
in curling up a little hook, the evaporation is said
to have been carried to the preuve are croc/zet. There
are, however, two kinds of crochet, the were/e and
the strong. For candies the prezwe (lZl sozggi'e', or
buckle-lest, is attained in open boilers, in which,
' on dipping a skimmer into the syrup, holding it
up vertically and blowing forcibly through the holes,
bubbles of syrup are formed on the other side: if
a large number of bubbles are detached in the blow-
ing, the proof is said to be sorjle‘forl: if only a few
bubbles are detached, the proof is then termed sozgfle’
leger. In the manufacture of barley-sugar and other
sweetmeats, there are proofs termed le pelz'l casse’, le
grarzcl came’, and le cassé sur le elozgl. The first of
these three is when the finger is moistened, dipped
into the syrup, then into cold water, and thus pre-
pared the sugar can be rolled into a ball, which, on
being thrown upon the ground, splits and loses its
shape. In the second kind of proof the ball thus
formed is suficiently hard and brittle to fly to pieces
when thrown on the ground. In the third kind of
79$
SUGAR.
proof the sugar solidifies on the finger into a brittle
envelope.
M. Payen has in the following table given precision
to the above tests, by assigning to them their re-
spective temperatures, and the proportions of sugar
and water in 100 parts of the sugar at each test :—
Tests. Temperature. 100 parts contain
Cent. Fahr. Sugar. Water.
Filet 109° = 228‘2° ... 85 15
Crochet lcger ....... .. 110'5° = 2309 87 13
“ fort .......... .. 112 = 2336 88 12
Soufiié leger .......... .. 116 '= 2408 90 10
“ fort .......... .. 121 = 249'8 92 8
Cassé petit............ 122 = 251-6 9267 7'33
“ grand ....... .. 128‘5 = 263'3 . 95'75 4'25
“ sur le doigt...‘ 132-5 = 270-5 96'55 345
If the defecation and clarification of the syrup
have not been well conducted, or if the proportion
of lime has been too small, the syrup is liable to
froth and foam up a good deal in the boiling. This is
corrected by throwing into the syrup a piece of butter,
which, in melting, spreads over the surface, lubri-
cates the bubbles, and enables them to glide over each
other and break, whereby they are prevented from
foaming over the sides of the boiler. An excess of
lime produces a contrary effect, especially if the beet-
root contain much oxalate of potash : the syrup will
not boil; an increase of heat deteriorates the liquor
by converting the sugar into caramel, and it is ex-
tremely difiicult to bring it to the point of crystal-
lization. In such a case the syrup must be filtered
through fresh animal charcoal, or be mixed with syrups
containing a little saccharate of lime or of potash.
The boiling is continued for 10 or 12 minutes, and
when the syrup answers to the desired test it is
drawn off into coolers or heaters, as the case may
be, and then poured into moulds, as described in
Section III. The centrifugal machine, Fig. 2114:, is
also used by many manufacturers of beet-root sugar.
The attempts to diminish the cost of production
of beet—root sugar have led to the invention of a num-
ber of ingenious processes, most of which, although
not successful in practice, are nevertheless worthy of
study as examples of manufacturing chemistry. Our
space, however, will not allow us to notice more than
one or two. The following process is based on the
chemical fact, that when sugar unites with lime its
properties undergo no change, and it may be recovered
with little or no loss. Now it was proposed in 1838
by M. Kulhmann, to employ an excess of lime so as
to convert all the sugar into saccharate of lime, and
after having undergone the processes of defecation
and evaporation to recover the sugar by saturating
the lime with carbonic acid. The proposed advan-
tages were the protection of the juice from all dete-
riorating influences and the saving of animal charcoal,
for it was supposed that filtration would not be ne-
cessary. This plan has lately been perfected in France,
and the following is a brief outline of it. The juice
is prepared in the usual way up to the point of defe-
cation, which process is conducted in a vessel similar
to that represented in Fig. 2099 heated by a steam-
jacket; but instead of the usual dose of lime being
used, six times that quantity is added to the juice,

sufiicient not only to act on the acids and other sub-
stances, but also to form a saccharate of lime (con-
taining 2 equivalents of sugar and 3 of lime) with the
whole of the sugar in the juice. About 25 kilogrs.
of lime are required for 1,000 litres of juice : the lime
is slacked with 5 or 6 times its weight of water, and
mixed with the juice, which is heated to from IéhOO to
150° Fahr.: the whole is then raised to about 203°, but
is not allowed to boil. The liquor is next decanted and
passed through a layer of animal charcoal 10 inches
thick, resting on a filtering cloth on the perforated
false bottom of a shallow vessel : the juice is limpid
but slightly yellow; it is passed into a second copper
heated by a steam-jacket, and here the lime is satu—
rated with carbonic acid, and the sugar set free.
The carbonic acid is generated by means of a blast of
air driven by a small blowing machine into a small
close furnace full of incandescent coke and charcoal.
The oxygen of the air in passing through the burning
fuel is converted into carbonic acid, and this, with the
nitrogen, is driven forward by the blowing machine,
first into a close vessel containing water where the
gases are washed, and then by a pipe from the top of
the washing vessel into the solution of saccharate of
lime, where it is delivered by a rose-head, which
divides the gas into numerous small bubbles. The
carbonic acid gas combines with the lime, producing
an abundant precipitate of carbonate of lime. When
the saturation is complete the supply of gas is cut off ;
the liquor is raised to the boiling point to expel the
excess of gas, and it is next passed into an ordinary
filter of animal black. The proceedings are afterwards
of the usual kind. M. Payen, who has'personally
examined the above process in actual operation,
recommends it as greatly facilitating the operations of
the manufacturer: it produces no pan—scratch in the
evaporating vessels ; the juice, which is purer than by
the ordinary method, never foams up in boiling, and
consequently requires no consumption of butter; the
quantity of animal black required for the filters is
only ififiths the usual quantity; the crude products have
an improved taste, and the crystallized sugar obtained
every day is equal to sugar refined in the usual man-
ner. M. Payen recommends that the carbonic acid
be generated by the combustion of a mixture of coke
and chalk, as is done in the process for manufacturing
Olz'c/zy white. [See LEAD, Fig. 1276.]
The secondary products of the beet-root are very
different from those of the sugar-cane. The pulp
which is left after the expression of the juice is an
excellent food for sheep and cattle. Its composition
varies with the kind of beet employed, and the manu~
facturing processes for extracting the sugar. In some
parts of the continent it is far more valuable than the
raw beet. The experiments and analyses of Dr. Sul-
livan, as stated in the Report already referred to, led
him to the remarkable result, “ that pulp is as nearly
as possible of the same value as raw beet, one consti-
tuent merely replacing another. In the raw beet the
sugar forms the preponderating constituent belonging
to the class of non-nitrogenous substances capable of
being assimilated by animals: in the pulp, a consi-
SUGAR
793
derable part of the sugar is replaced by pectine, which
fills the same office as food.”
The melasses from raw cane-sugar is also essen-
tially distinct from the melasses of the beet-root; the
latter consisting of the mother liquor more completely
exhausted, with less sugar and more foreign ingre-
dients. They contain, however, all the non-crystalline
sugar to which the cane-sugar of ‘the beet has been
degraded, and other organic matters of the juice,
together with saline matter, gum, or mucus, to which
beet-root melasses owe their nauseous taste. They
are occasionally mixed with the refuse pulp and given
to cattle, and are also used for the production of
alcohol: they contain about half their weight of solid
sugar, and yield about 30 per cent. of their weight of
alcohol. The residue after distillation is dried and
calcined, and leaves about 10 or 12 per cent. of the
weight of the melasses in the form of a saline mass,
rich in alkali, containing from '7 to 11 per cent. of
sulphate of potash; 17 to 20 per cent. of carbonate
of potash, 27 to 1145 per cent. of chloride of potassium,
25 to 34- per cent. of carbonate of soda, and traces of
cyanide of potassium. Thus the production of potash
may be connected with the distillation of melasses for
alcohol, the residue being used for diluting fresh por-
tions of melasses. In factories where the daily con-
sumption of beet is about 600 cwt., about 5 or 6 cwt.
of mineral ingredients, and 3 to 41 cwt. of this saline
mixture are produced. When the calcined saline
mass is purified by solution, a double salt crystallizes
=KaO,C()2+NaQCOz-t-IQaq, which can be con-
verted by means of carbonic acid into carbonate of
potash and bicarbonate of soda.
The scum which is removed during the process of
defecation, and the residue left in the filters after the
separation of the filtered juice, together with the
waste of the bone-black employed in the filters, form
a valuable manure. The scum consists of an excess
of lime, phosphate of lime, and magnesia separated
from the juice; a great part of the nitrogenous sub-
stances found therein; organic acids in combination
with lime, 850.
SECTION VI.——MANUFACTURE or MAPLE SUGAR, ncrc.
Several species of maple contain a sweet juice in
their stems of the sp. gr. 1'003 to 1006, which, on
being evaporated, yields a syrup containing cane-sugar.
The deer sacc/zarz'rzum is most abundant in juice. In
the United States and Canada the maple forms large
forests, and the manufacture of sugar from its juice
is a regular branch of industry. It is necessary, how-
ever, frequently to change its locality, since the opera-
tion of tapping the tree for its juice is injurious to
its economy. The tools consist of a few large awls
or borers, wooden pipes of the size of the awls for
drawing ofi' the juice, and troughs for collecting it;
boiling-pans of the capacity of 13 to 15 gallons;
casks, moulds, and axes for clearing wood for fuel.
The juice is collected in February and early in March,
when the sap is most abundant. Two holes are bored
on the south side of the tree, 4 or 5 inches apart, and
18 or 20 inches from the ground: they are made to

slope upwards, and do not penetrate more than half an
inch into the white bark or splint of the stem, which
yields the largest quantity of juice. The juice is col-
lected during about 6 weeks, at the end of which
time it becomes more impure, and contains less sugar;
From the troughs it is removed by cans into a hut,
and poured into reservoirs which supply the boilers.
The juice cannot be kept for more than 2 or 3 days,
according to the temperature, without fermenting.
The boilers are heated by a brisk fire, and the scum
is removed as fast as it forms, and fresh juice is added
as the bulk diminishes by evaporation. The syrup,
when properly concentrated, is strained through a
woollen cloth, then boiled quickly down in another
pan, cooled, and poured into moulds to crystallize.
When the syrup has drained off, the remaining sugar
is dry in the grain, of pure taste, and equal to raw
colonial sugar. The maple juice is much more free
from foreign matters than that of the beet. The
proportion of sugar in the juice of the maple has been
variously stated; but it probably does not contain
more than one half the sugar contained in the. juice
of the beet.
The stems of Indian corn also contain sugar, and
attempts have been made to manufacture it. It has
been stated that 8,700 stems yield 7,131 lbs. of juice,
from which 35 lbs. of crystallized sugar ‘and 7 0 lbs. of
syrup are obtained. The quantity of sugar in the
stems varies in different countries, and the economy
of the manufacture does not appear to have been well
ascertained.
The common gourd, Cucurbiz‘a papa, has been used
in Hungary for the manufacture of sugar: the gourds
are said to contain 82 per cent. of juice, of 10° to 11°
13., and to yield a species of raw sugar moderately
coloured, and having the taste of melon: but by re-
fining it yields sugar equal to that of the cane.
The various kinds of palms also contain in their
stems a juice charged with cane-sugar, which, in the
fresh state, is named ZOcZduJ, in India, and when fer—
mented and distilled, arms/r: it is by the evaporation
of toddy that the “sugar termed jagery is obtained.
The process is noticed under Coco-NUT TREE. The
Ryots, or poor peasants dependent on the land-owners
in the East Indies, also cultivate the sugar-cane, ex;
press the juice, and boil it down to a thick syrup:
they then transfer it to the Goldars, who produce the
solid sugar. The crude syrup is named ‘9007', and is
of various qualities, one of which, in common use, is
also called by the English settlers jagery. There is
an association of farmers, who convert the syrup and
send the produce of each man’s land to a common
manufactory. Jagery is sometimes adulterated with
earth and sand. The French colonists of Pondicherry
prepare refined sugar from jagery: it is of a yellowish
white colour: it is known in the English market
under the name of date sugar. A similar product from
Africa is known as date-sugar oj‘Mogador (the port
of Morocco).
Chestnuts, the fruit of the Cactus 01224726222, and a
species of wild daffodil (Aqpl’zodelus), have all been
proposed as sources of sugar.
796
SUGAR.‘
_ tained.
SECTION ‘UL—MANUFACTURE or RUM.
The refuse of the sugar-cane is chiefly employed in
the manufacture of rum. The melasses, the skim-
mings from the clarifying and evaporating coppers,
and even raw cane-juice diluted with water, are all
used for this purpose ; dander, or the wash of former
operations, deprived of its alcohol by distillation,
being used as a ferment. The fermentation is com-
plete in from 5 to 7 days, and the liquor must be
transferred to the still before the acetous fermentation
shall have set in. A small portion of lime or of solid
limestone is added to correct any acidity that may
have formed. The spirit is allowed to flow through
the worm until it is no longer inflammable. It is
then rectified in a smaller still. [See Drsrrnnxrron]
Mr. Vlfray1 states that 1,200 gallons of wash yield
113 gallons of proof rum. Rum is coloured by means
of caramel.
Mr. Wray lays great stress on the action of the
dunder. He terms it the aromatic substance which
modifies the changes or transformations which take
place during fermentation: that it increases the den-
sity of the liquor, and prevents violent fermentation;
that good dunder should be light, clear, slightly bitter,
and quite free from acidity; and that its action is
similar to hops in diminishing the influence of decom-
posing azotised bodies, which is to convert alcohol
into acetic acid.
Messrs. Pontifex 817 Wood, who have done so much
for the improvement of the sugar apparatus of our
colonies, have also brought out a still for facilitating
the production of rum. They have lately patented a
continuous distilling apparatus, for obtaining a spirit
of any required strength by a single distillation. This
object is attained by certain arrangements based on
the well-known principle [see DISTILLATION] that
spirit will remain in a state of vapour at a much lower
temperature than water. If, then, the vapour which
rises from the wash, and which contains both spirit
and water, can be reduced in temperature, the former
only will remain vaporized whilst the latter will be
condensed, a strong spirit being thus at once ob-
The agent used for reducing the temperature of the
mixed vapours is the cold wash itself, which, com-
mencing at the point whence the vapour is about to
pass into the worm, gradually traverses the different
parts of the apparatus, assimilating to itself the waste
heat from the vapours, which is usually lost, until
it arrives at the body of the still, by which time, in
consequence of its having been all along in contact
with the hot rising vapour, it has been completely
robbed of the whole of its spirit, and is therefore at
once run off through a waste pipe. The hot vapour,
in its gradual ascent, meets with the descending
stream of cold wash, from which it withdraws the
spirit, and by which it is sufficiently reduced in
temperature to free it from the watery particles.
The steam rising‘from the body of the still A, Fig. 2116,
is first met by the descending column of cold wash

(1) “The Practical Sugar Planter,” by Leonard Wray.
London, 1848.
8vo.
in the rectifier c; as much of the vapour of water
as is required to be separated is there condensed by
regulating the supply of cold wash and so raising or
lowering the temperature as required, the spirituous
vapour passing over into the worm tub D. In the
analyzer B the wash, which has already robbed the
it
ll ‘ll’
uluiliiillillllliitinuflllm lHllifll
Illl lllllllillri‘lfilfilllllllllllllllllilllll llll'llltllllllllllllllllllllllllldlllllglJ llama‘
aimu -,
flllllllljlllllllmlglgflnmmmum .
ll ‘www.mz=7| [1 |
‘W
“a.”
,—
g
_-
-
l
tiara!‘
:
L'_- at’:
__.\_
. Im '
tin ’
mpif'l‘lzlllflllllllflllllllllllgflg
v.
lllllll
lllllllllllllllllll
numlillll lllllllll

Fig. 2116.
vapour of its watery particles, is in its turn robbed
by the vapour of its spirit, which, with some vapour
of water mixed with it, passes over into the rectifier
to have the latter separated by fresh portions of cold
wash. The wash-pipe is shown at n.
The separation of the vapour of spirit from the
vapour of water is effected in the analyzer by a very
peculiar arrangement, the stream of wash being made
to fall in a shower of minutely divided particles,
through the midst of which the mixed vapour is rising,
and which is thereby much reduced in temperature,
causing the watery particles to separate and fall back
into the still, whilst the hot vapour continues its on-
ward course, taking with it the spirit from the wash.
The supply of cold wash being constant, and the waste
wash from the still always running off at G, the conti~
nuous action of the still is effected, and the time usually
lost in charging and discharging is thereby saved.
The peculiarity of this arrangement is, that the
still itself merely supplies the heat which is to effect
the distillation, that being in fact completed before the
wash reaches the body of the still, and its advantages
are an immense saving of time, fuel, and labour,
considerably lessening the cost of the apparatus, and
rendering it much less cumbersome.
It will be seen from Fig. 2116 that this still may
be adapted either to work by fire or by steam. If by
steam, the body of the still A, which may be made
either of copper or of wood, will be represented by the
square box s’ s’, with F for the steam—pipe. If by fire,
the body A is of the ordinary form, in which n is
the discharge-cock.2
(2) Messrs. Pontifex 8; Wood, to whom we are indebted for
information in the preparation of this article, have furnished us
with a few notes on the last sheet (p. 769 to p. 784), which they did

SUGABwSIlLBIIfiRT
‘797'
Snorion VIIL—Sratrisncs or Susan.
The production of sugar in the year 1850 has been
‘stated in the Eeouomz'sl as follows :-
1. FREE Lanoun.
tons. tons.
British possessions 260,000 260,000
nonnren rnnn LABOUR.
90,000
30,000
Java Manilla, Siam, and China United States, maple sugar 70,000
French West Indies and Bourbon... 60,000
Europe beet-root 190,000
olotoolooulvuo one...‘ II
440,000
Total free-labour sugar .... 700,000
II. SLAVE Lnnoun.
Cuba 250,000
Porto Rico 46,000
Brazil 110,000
Dutch W'est Indies 13,000
Danish 8,000
124,000
Ilt'lbOIllIllll'
Louisiana 551,000

III'IIO'IIIIC'IC'OQ‘QII"...
The consumption of sugar per head in the following
countries has been thus estimated :—

lbs.
In the countries of the German League......... 4'08
France 65
Holland 145
Belgium 7'0
Russia 0'5
45
England and Scotland................................. 210
The United States 14-5
560
Venezuela 100 0
not see until after it had gone to press. It is stated on page 774,
that the Batavian cane is cultivated in Java chiefly for the manu-
facture of rum; whereas no rum is manufactured in Java at the
present time. With respect to the mills, such as Fig. 2094, the
main improvements consist in a. better and more scientific distri-
bution of the strength of material, and the moderate speed at
which the rollers are driven. At page 7 77 is noticed a proposal
to dip the crushed canes into water, and pass them a second time
through the mill. In addition to the objections stated in the text,
it has been remarked to us that by this plan the organic acids, 850.
would be so largely extracted as to produce more injury to the
juice than would be compensated by the increased quantity of
sugar. In the process of defecation, p. 778, we are informed that
an important improvement is about to be brought out, which will
admit of any quantity of lime being used, from which the sugar
may afterwards be separated by very simple means. We have
already referred to a plan of this kind, p. 794, in which carbonic
acid is used for separating the sugar from the lime; but the plan
in question is said to be much simpler. Messrs. Pontifex 8zWood
state that the method of concentrating the juice for the vacuum-
pan, p. 781, and Fig. 2104, was patented by them in England, and
by M. Derosne in France. Respecting the use of butter or grease
in the vacuum-pan, p. 783, when it is required it is a proof that
the operation has been’ badly conducted, and that incipient fer-
mentation is causing undue ebullition. In the same page it is
stated that proof-sugar boils at 145° in the vacuum-pan, when the
pressure is 3 inches above a perfect vacuum The word above
should be below. If the mercurial column were acted on by the
pressure of the vapour within the pan, and that were capable of
supporting 3 inches of mercury, then the expression 3 inches
above a perfect vacuum would be correct; but as the barometer-
tube opens into the vacuum-pan, and the mercury is supported
in it by atmospheric pressure, then 3 inches below a perfect
vacuum would be a height of mercury equivalent to 27 inches,—
30 inches marking a perfect vacuum, as in the case of the gage
attached to the air-pump, d, Fig. 20. [See Ann] In p. 784 the
sugar is stirred in the heater to promote not to prevent granulation.
The reader who desires a. fuller notice of this important manu-
facture, will do well to consult the third volume of the English
translation of Knapp’s Technology: the sixth volume of Dumas’
“ Traité de Chimie appliquée aux Arts,” and Payen’s “ Chimie
Industrielle,” 1851.

The quantity of sugar imported into the United
Kingdom in the years 1851 and 1852, was as fol-
lows :—


1851. 1332.
From Rf‘fined. l Refined,
Unrefined. and Sugar Unrefined. and Sugar
and). 1 Andy.
British west Indies C“ t. on 8. cwt. C“ t.
and Guiana 3,064,793 60 3,393,700
Mauritius ............. .. 999,237 23 1,121,996 1-111
British East Indies 1,565,878 31,400 1,301,982 2,541
Ceylon..................... 4,874 2 1,667 Singapore 81 Other parts 1,367 9,495 35
5,636,230 31,490 5,833,900 4,354
Foreign countries 2,296,304 417,051 1,068,564 299,511

The total amount of sugar from British possessions
entered for home consumption was, in the year ending
5th Jan. 1852, 4,890,430 cwts; the amount of duty
received 2,550,148l. Of the foreign sugar, 1,681,196
cwts. were enteredlfor home consumption: the amount
of duty received was, 1,428,992l.


MELASSES— 1851. 1852.
cwts. cu ts.
From British West Indies and Guiana 492,056 472,933
,, Mauritius 740 ... —-
,, British East Indies 9,848 5,580
Of foreign produce 2,621 420
Total 505,265 478,933
RUM-—
gallons. gallons.
From British West Indies and Guiana 4,176,137 5,058,023
,, Mauritius 21,442 8,097
,, British East Indies 414,818 307,382
,, 35,347 21
Total 4,647,744 5,373,523
After the 5th July, 1854, the duties on foreign and
colonial sugar, then to be equalized, will be on refined
sugar, 13s. 4d. per cwt.; on white clayed, 11s. 8617.;
on brown, 10s.; and on melasses, 3s. Qrl.
The average price of West India brown sugar in
1842, was 37s. per cwt. ; in 1852 it was 24s. 262.
A plan has been recently introduced for recovering
from melasses the crystalline sugar: 3 lbs. of me-
lasses are found to yield 1 lb. of sugar.
SUGAR OF LEAD. See LEAD.
SULPHATES. See SULPHUR.
SULPHUR (3.16). This important element is
very abundant in nature, and occurs in greater or
less quantities in minerals, animals, and plants.
When united with metals it forms sulplurels, and
when combined with metallic oxides the compounds
are termed sulplzuzfes. Native sulphur is also found
in crystals, its primitive form being an acute octohe-
dron with rhombic base, which is the figure assumed
by sulphur on separating from solution at common
temperatures; but when a mass of sulphur is melted,
and after partial cooling the surface-crust broken
and the fluid portion poured out, it then has a difl'e-
rent primitive form, viz. an oblique rhombic prism.
Pure sulphur is a pale yellow, brittle solid, insipid
and inodorous, but exhalinv a peculiar odour when
*
798
SULPHUR.
heated. Its density is 1'97 0 to 2080. Its specific
heat 01880. It becomes negatively electrical by heat
and by friction: it is a non—conductor of electricity,
and a bad conductor of heat. If a piece of roll sul-
phur be ground in a dry Wedgwood-ware mortar, the
powder will adhere to the mortar in consequence of
the electricity developed by the friction, so that the
mortar may be inverted without losing the sulphur.
If a roll of sulphur be grasped in the hand, it will
split to pieces with a crackling noise in consequence
of the unequal expansion under a very slight heat.
Sulphur may be obtained in three states. At ordi-
nary temperatures it is solid: if it be heated to 232°
and upwards it fuses into a very limpid fluid of a
canary yellow colour: fragments of sulphur not
melted remain at the bottom of the test-tube or
vessel in which the experiment is conducted, show-
ing that sulphur, in passing from the solid to the
liquid state, increases in volume.1 Sulphur passes
suddenly from the liquid to the solid state without
any intermediate viscid or sticky condition. If,
when the sulphur is quite limpid and of a clear
yellow colour, the temperature be raised, its colour
deepens and it diminishes in fluidity. At 320° it pours
with difiiculty, and is of a brownish colour. At 392°
it is so viscid that the mouth of the vessel containing
it can be reversed and the sulphur will not escape:
the colour‘ is then of a deep brown. If the tempera-
ture be still further increased, the sulphur becomes
again fluid, ‘retaining its brown colour. At 7 52° it
boils, and may be distilled in a glass retort over a
charcoal‘ fire. The vapour condenses in the neck
of the reto'rt in the form of a very fine powder, known
as flowersiqif sulfa/tar, If the distillation be continued
until the neck of the retort exceed 232°, the tempera
ture at which sulphur fuses, the vapour then con-
denses' in the liquid state. In this way sulphur
may be purified of foreign non-volatile substances.
The vapour of sulphur is of a yellow brown colour,
and of the density of 6'6541, air being 1'000.
' If sulphur be heated in a crucible to about 400°,
and then poured in a. thin stream into cold water,
a brown, spongy, soft, and elastic mass is obtained,
and its softness continues some time; it gradually
hardens, and ‘after some days it regains its ordi-
nary condition of hardness, but its colour continues
to be deeper than usual. But if, instead of leaving
the soft sulphur to recover its hardness at the ‘usual
temperature of the air, it be heated to about 212°, it
changes suddenly into hard sulphur with disengage-
ment of heat: the soft sulphur heated to 212° rises
to 230°. The soft ductile sulphur may be used for
making casts and receiving impressions of seals, &c.
The. temperatures at which the above remark-
able series of changes take place are stated on
the authority of Regnault. They differ from those
which are given by Dumas as stated in the following
table :—

(1) This is not the case with water; ice, which is of less density
than water, in passing from the solid to the liquid state, dimin-
ishes in volume. [See 102.]

- When suddenly cooled by
Temperature. Heated Sulphur. plunging-it into water.
230° Very liquid, and yellow Very friable, but of the
usual colour.
284° Liquid; deep yellow ....... .. Ditto, ditto.
338° Thick; orange yellow .. Friable; the usual
colour.
374° Thicker; orange .. At first soft and trans-
parent, then friable
and opaque; colour
as usual.
428° .......... .. Viscid; reddish Soft; transparent; and
of an amber colour.
464° to 500° . Very viscid; brown red Very soft; trans-
parent; reddish.
Boiling point Less viscid; brown red .... .. Very soft ; trans-
parent; brown red.
Sulphur is found in large quantities in volcanic
districts : it impregnates the ashes of certain extinct
craters or solfaterms. It is also found in beds, as in
Sicily, whence our chief supply is obtained; there it
occurs in beds of blue clay, which occupy the central
half of the south coast, and exteiid inwards as far as
Etna. One of the excavations is said to resemble
a marble-quarry, the various colours of the sulphur
mingled with clay, calcareous stones and gypsum
being compared to the veins in marble. The general
ground colour is a rich shining grey; this is crossed
by veins of sulphur of various colours, some much
brighter than others. The veins most deeply coloured
are nearly red and transparent, and contain what the
miners call virgin sulphur. The fragments of sulphur,
as they are got out, are collected into a heap, and
melted in furnaces resembling cauldrons, 6 or 7' feet in
diameter, and 41 or 5 in depth. A small opening in
front of each of these is closed up with moist earth.
The largest lumps of sulphur ore are arranged on a
ledge fixed near the bottom of the furnace; smaller
masses are next piled up, and still smaller upon these,
until a sort of cupola or dome is formed ; the irregu—
lar spaces are filled up with small lumps of the ore;
and, lastly, the mere dust of the ore is piled up so as
to form a sort of pyramid. The lower part is then
covered with fine earth, arranged in a sort of conical
belt 6 or 8 inches wide, for preventing the too rapid
escape of the fumes after the furnace is lighted. In
the course of all this piling up, care is taken to leave
a small hole in the top. The fire is applied to this
hole by means of a wisp of straw. The outer part of
the pyramid first burns, but the fire soon gets to the
interior. In about 7 or 8 hours the sulphur is extracted
from the ore, and is found in a liquid state at the
bottom of the furnace. The moist earth which closes
the hole at the bottom is then perforated, and the
liquid sulphur is received into wooden moulds of the
form of alarge brick. These are first moistened to
prevent the ‘sulphur from adhering, and in a quarter
of an hour the sulphur-blocks can be taken out.
The earthy residues of the above operation, toge-
ther with poor ores, are distilled in a rude kind of
apparatus, shown in Fig. 2117. Two rows of earthen
pots, p p, are arranged in a close furnace upon sup-
ports, so that the necks of the pots can be let into
the top of the furnace, leaving the months free; the
pots can thus be charged from without, after which >
the lids are ‘cemented on, the fire is lighted,'and the
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Fig. 2117.
side, where they condense into liquid sulphur, which
is received in tubs of water.
For a large number of purposes the crude sulphur
of commerce requires to be refined. This is done by
distilling the crude sulphur and recovering it in the
form of flowers, or running the melted distilled pro—
duct into wooden cylindrical moulds. The furnace
used for the purpose in France was contrived by M.
Michel, of Marseilles, and is represented in vertical
section in Fig. 2118. The distillatory vessel is a


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F29. 2118. FURNACE FOR DISTILLING- SULPHUR.
large cast-iron retort I I, and the cooler or receiver
a spacious chamber of masonry o. The boiler or
retort I is heated by a fire beneath, and it is fed by
means of a second boiler B situated over it, and
heated by the hot air of the flue before it escapes
into the chimney c. A channel leading from the
bottom of the boiler B into the retort I conducts the
melted sulphur into I when the plug in B is pulled
up. This contrivance allows the distillation to be
carried on continuously; whereas formerly it was
necessary to open a door in the side of the retort I
to put in a fresh charge, and the atmospheric air
coming into contact with the heated sulphur-vapour,
would sometimes produce violent explosions. The

preliminary fusion in the boiler B also allows the
sulphur to deposit some of its impurities before it is
let down into I. The vapour of sulphur raised in
the vessel I passes along its neck into the chamber
0, where it condenses under the form of flowers of
sulphur. The hot air of the chamber may be allowed
to escape by the valve V; and if it be desired to have
the sulphur only in the form of flowers, the chamber
must be of large size, and be kept below 232°, and
the operation be conducted slowly, and interrupted
often, so as to keep the chamber below that point.
The flowers are removed when the chamber is cold,
by a side-door provided for the purpose. If liquid
sulphur is required for casting into rolls, the chamber
must be smaller, and the operation conducted without
interruption: the temperature of the chamber soon
rises above the fusing point of sulphur, which accu—
mulates in the bed of the chamber 5, from which it
may be drawn off by the gutter I,‘ on loosening the
plug 0 by means of the handle 2'. The moulds are of
deal, slightly conical, and moistened to prevent the
sulphur from adhering. The lower end of each
mould is plugged before the melted sulphur is poured
in; the sulphur crystallizes first at the sides of the
mould, and afterwards at the axis; it contracts on
cooling, so that the rolls are easily removed from the
moulds.
Some remarks respecting the commercial import-
ance of sulphur will be found in our In'rnonue'ronv
ESSAY, p. cii. In the year ending 5th January, 1852,
the quantity of brimséorzel imported into the United
Kingdom amounted to 768,299 cwts.
The most important compounds of sulphur and
oxygen are sulphurous acid, SO2. and sulp/zme'c acid
803. The former is produced when sulphur is burnt
in dry air or oxygen gas. It may also be prepared by
heating sulphuric acid with mercury or clippings of
copper; part of the acid undergoes decomposition,
one-third of its oxygen being taken up by the metal,
and the sulphuric acid becomes converted into the
sulphurous. Sulphurous acid is a colourless gas, with
the suffocating odour of burning brimstone; it extin-
guishes flame and is irrespirable. Its density is 2'2],
and 100 cubic inches weigh 636%) grains. At the
zero of Fahrenheit’s scale sulphurous acid condenses
into a limpid colourless liquid. Cold water dissolves
more than 30 times its volume of sulphurous acid. If
the solution be exposed to air, the oxygen gradually
converts the sulphurous into sulphuric acid. Sul-
phurous acid, or the fumes of burning sulphur, is
sometimes used for fumigating apartments for the
purpose of destroying insects. This gas may also be
used for extinguishing the burning sect of a chimney
on fire, for which purpose a handful of sulphur thrown
into the grate may be sufficient. Access of air to the
fire ought, however, to be excluded by means of a
damp cloth. Sulphurous acid has bleaching proper-
ties, and is used for whitening woollen goods, silk,
isinglass, sponge, and the straw used in the straw-hat
manufacture. The articles to be bleached are hung

(1) From the Saxon bremze-stone, or burning stone.
800
SULPHUR.
in a damp'state on strings across a close chamber, in
the corners of which pots of burning sulphur are
placed; all the openings are stopped with wet clay
during the sulp/iuriug, except one hole for admitting
a limited supply of air, and another for the escape of
the used gases. Of late years, however, an aqueous
solution of sulphurous acid, or sulphite of soda or of
potash in solution, has been used as a far more conve-
nient method of applying the bleaching properties of
sulphurous acid. Fruit stains may be removed from
linen in this way. Sulphurous acid is also used for
altering the colour of hops, for modifying fermentation
in wine-vats, and for fumigating casks in which fer-
mented liquors are to be kept in order to prevent
acetous fermentation.
Sulphuric acid. S03. The discovery of this impor--
tant compound is one of the numerous obligations
which we have received from the alchemists. As
heat of varying intensity was the grand agent of those
remarkable men, they applied it in various ways to
the different substances with which they were ac-
quainted. Thus Basil Valentine, a monk of Erfurth
in Saxony, about the year 141410, distilled a quantity
of green vitriol,‘ or sulphate of iron, in a retort at a
red heat, and he obtained an oily, smooth-pouring
liquid, which he named oil ofuiiriol. The solid brown-
red substance left in the retort was called cupui mor-
iuum viirioli.2 He also discovered that the acid vapour
produced by the combustion of sulphur in the air
may be collected in a liquid form by burning the sul-
phur in a crucible under a bell-glass, moistened
with water, and suspended so as nearly to touch the
dish containing the crucible. After some hours, a
small quantity of acid was produced, which was
named oil of sulphur per cuuipuuum, or by the bell.
The solution was made stronger by boiling it in a
glass vessel. To Valentine are we also indebted for
the germ of the modern process of producing sulphu‘
ric acid. In a curious work, entitled “The Chariot of
Antimony,” he states that oil of antimony may be
made by burning equal parts of sulphur, sulphuret of
antimony and nitre under a bell-glass. In the modern
process of manufacture nitre is mixed with the burn-
ing sulphur, for the purpose of enabling it to receive
its highest degree of acidification.
Sulphuric acid continued to be a costly article

(1) The term vitriol was applied by the chemists to several
salts, probably from their resemblance to glass, 'vitrum.
(2) Now called Colcothar: it is used as a paint. It is also pre-
pared by mixing 100 parts of green vitriol with 42 of common salt,
calcining the mixture, washing away the resulting sulphate of
soda, and levigating the residuum. The polishing powder known
as jeweller’s red rouge, or plate-powder, is prepared by adding a
solution of soda to one of sulphate of iron; and washing, drying,
and calcining the precipitated oxide of iron in shallow vessels
until it is of a deep brown-red colour.
The alchemists named the fixed residue of a distillation a caput
morluum, and represented it by a death's-head, under the idea that
it was inert and useless; while the volatile matter which rose
from such dregs being active and strong, was called the animus or
spm'it, and was represented by‘a bow, denoting strength or power;
" or, if it happened to be an acid spirit, then by a bow and barbed
arrow-heads; the bow denoting strength, the arrow heads sharp-.
ness and swiftne‘ss of action; the barbs denoting the difficulty of
extracting the’ acid from ‘its combination, as barbed arrow-heads
were diflicult to extract from wounds.

until comparatively recent times. The oil of sulphur
per campanum was long sold at the rate of 2s. 6d.
per oz., and the common oil of vitriol from the sul-
phate of iron at about the same sum per 1b., and it
was regarded as an important improvement, when
Homberg was able to produce 5 oz. of oil of sulphur
in 24¢ hours.
About the year 1740 a proposal was made still
further to increase the product: it was suggested by
two French chemists, that as nitre contains 418 per
cent. of oxygen, it might be mixed with sulphur, and
the combustion be carried on in close vessels. It was
thought that the quantity of oil of sulphur would thus
be increased, which really is the case, even when the
nitre is far too small in quantity to supply the oxygen
required; for it acts in a diiferent manner, as will be
explained hereafter. Dr.Ward adopted the suggestion,
and took out a patent for the manufacture. 1:16 erected
his apparatus at Twickenham, and afterwards ‘at
Richmond, near London. He used large glass re-
ceivers containing a few pounds of water, and arranged
in a sand-bath with the necks projecting, as shown in
Fig. 2119. A small
stoneware pot was
placed in each re-
ceiver, supporting a
shallow dish, into
which a ladleful of
sulphur mixed with
—§—th its weight of nitre
was introduced. This being kindled by a hot ‘iron,
the necks of the receivers were closed with wooden
stoppers. Combustion went on for some time, and
the water absorbed the acid vapours. The air in each
receiver was then renewed, and a fresh charge intro-
duced. This was done several times, until the water
became highly acidulated. It was then drawn oil’,
and concentrated by boiling in glass retorts. A strong
acid was thus produced, and sold at what was then
the low rate of from 18. 60?. to 28. 6d. per lb. It was
called oil of uiiriol 5y ile bell, in order that people
might suppose it was formed by the combustion of
sulphur under a bell-glass as already described.
The use of these large glass receivers was both
expensive and dangerous, and served to keep up the
price of the acid. Dr. Roebuck, of Birmingham,
suggested the use of lead vessels instead of glass, and
thus arose the present method of manufacture. The
first leaden chamber was erected about the year 1746;
but the expense and risk of land carriage (the only


1"iy. 2119.
. means of conveyance at that time) caused the product
of the manufacture for some time to be chiefly con-
fined to Birmingham and its neighbourhood. When
this acid superseded the use of sour milk in bleaching, *
sulphuric acid works were established at Preston Pans,
on the eastern coast of Scotland. ‘In a few years
Messrs. Roebuck and Garbett supplied the home de-
mand at a reduced rate, and exported large quantities
to the continent. In 1756 one of their workmen went
to Bridgenorth, his native place, and induced one
Rhodes, a seed crusher, to embark lll't the business.
After this the method of conducting the process
SULPHUR.
801
became known, and acid works with lead chambers
were established in many places.
We have seen that sulphurous acid, 802, is pro-
duced simply by burning sulphur in the Sulphuric
acid, 803, is not so easily produced, although so simple
in its composition. In fact, it is ‘in order to make
burning sulphur take up three instead of two propor-
tions of oxygen that the extensive and costly arrange-
ments of the sulphuric acid works are required. The
chambers, or houses, as they are called, in which the
acid is formed, vary in dimensions from 60 to 200 feet
in length, and of proportionate height and width.
They are raised 8 or 10 feet from the ground by means
of brick piers, and are lined internally with sheet lead,
which is not corroded by sulphuric acid at common
temperatures. The lead which covers the bottom of
the chamber should weigh from 8 to 10 lbs. per square
foot, but lead of half that thickness is suflicient for
the top and sides. The edges of the sheets are burnt
together by the autogenous method described under
Sonnnnrue; a tin solder being rapidly corroded. The
thick lead which covers the bottom is turned up at
the sides, so as to convert the bottom into a large
trough about 12 inches deep. The floor is in some
cases divided into compartments by means of ridges
of lead, each compartment having its own exit pipe
for drawing off the acid: and in other cases the
whole chamber is divided into compartments by
means of curtains of lead. See Fig. 2120.
There are 40 substances used in the production of
sulphuric acid: viz. I. sulphurous acid, formed by the
combustion of sulphur in air. 2. Nitric, nitrous or
Izyporzz'irous acid, supplied by the nitre, and by means
of which the sulphurous acid is enabled to take up
another equivalent of oxygen. 3. Atmospheric air,
which must be constantly renewed for the sake of its
oxygen. at. Water or steam, for the purpose of dis-
solving and retaining the sulphuric acid as fast as it
is formed.
The sulphur which supplies the sulphurous acid is
burned at one end of the chamber on a flat hearth of
the oven 0, Fig. 2120, which at first has a small fire
4??
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Fig. 2120.
SULP HURIC ACID CHAMBER.
under it, but this is allowed to go out when the
sulphur is fairly ignited. B is the boiler which sup-
plies the chamber with steam. Immediately over the
burning sulphur an iron pot is suspended or mounted
on a tripod: it contains nitrate of potash or of soda
mixed with the quantity of sulphuric acid required for
its decomposition. From 8 to 10 lbs. of nitre mixed
with 5 or 6lbs. of sulphuric acid are used for every
cwt. of sulphur. The heat of the burning sulphur
distils off the nitric acid from the nitre, and the
VOL. II.

sulphurous acid and nitric acid vapours are conducted
by means of a wide leaden tube 12, from the furnace
into the chamber, where these vapours meet with steam
which is admitted near the same point by the tube If,
and also by jets j distributed through the chamber:
the steam causes a more intimate mixture of the
gases, and assists the chemical changes which we will
now describe.
Sulphurous acid gas, as already noticed, is capable
of taking up another equivalent of oxygen from moist
air; but it does so slowly, and for the purposes of
the manufacturer the process is required to be quick.
Sulphurous acid gas takes oxygen rapidly from nitric
acid, N05, thereby reducing it to nitric oxide N02, a
gas which, by mere exposure to air, takes up an
additional supply of oxygen, generally 2 equivalents,
so as to form nitrousracid, N04. Sulphurous acid
also readily takes an additional supply of oxygen from
nitrous acid, provided moisture be present. Two
more equivalents of sulphurous acid thus become
converted into sulphuric, and the nitrous compound
becomes reconverted into nitric oxide, in which con-
dition it is again fitted to abstract oxygen from the
air, and thus to continue the action. Hence a com-
paratively small amount of nitre is sufficient to convert
a large portion of sulphurous into sulphuric acid, and
were it not that the nitric and nitrous gases are driven
off with the nitrogen of the chamber by the chimney
o, a small fixed quantity would sutfice for a long time.
In some works the valuable nitrous compounds are
retained by passing the waste of the chamber through
a stream of sulphuric acid, which absorbs them, and
they are afterwards separated and returned to the
chamber. In some works the chamber is divided into
3 or a compartments, by means of curtains of sheet
lead proceeding alternately from the top nearly to the
bottom, and from the bottom nearly to the top. It
is supposed that these curtains detain the vapours,
and cause them to advance gradually through the
chamber, so that the sulphuric acid is almost com-
pletely deposited before the vapours reach the dis-
charge tube (3, Fig. 2120, which communicates with a
tall chimney, or with the apparatus for separating the
nitrous acid gas from the waste gas of the chamber.
The mode in which this separation is effected in
the French works, and some further details respecting
the manufacture, will be understood by referring to
the steel engraving. In some of these works not
more than 3 lbs. of nitre are required to convert
100 lbs. of sulphur into 300 lbs. of acid: it is, how-
ever, common to employ free nitric acid instead of
that acid in combination with potash or soda. The
sulphur is burnt in the furnaces A and a, and the
sulphurous acid is conducted by the leaden tubes B B
into 0, the capacity of which is equal to the sum of
BB. A boiler for supplying steam is heated by the
burning sulphur in A, and is supplied to the burning
sulphur, and the combustion regulated by raising the
sliding door a more or less. The sulphurous acid,
together with the oxygen and nitrogen of the air,
pass up the chimney into 1), and so into the first
chamber or z’ar/zbour EB’, the jet of steam x assisting
3 r
802
SULPHUR.
the draught of the fires A a, and the chemical reactions
already noticed. The gaseous mixture impelled for-
wards by the constant generation of sulphurous acid
and steam in Act, passes from the first chamber by
the tube E2 into the chamber E3, where it comes in
contact with nitric acid which is supplied from the
vessels f to a couple of cascades gg’, down the steps
of which it falls, and exposes a large surface to the
sulphurous acid gas, which takes from it oxygen, and
becomes convertedinto liquid sulphuric acid, reducing
the nitric acid to the state of nitrous acid. The
sulphuric acid‘ thus formed is conducted by a small
pipe into thejfirsti chamber E’, where the sulphurous
_ acid and the vapour of water convert the nitric and
nitrous acids which accompany the sulphuric acid, the
one into nitrous acid and the other into binoxide of
nitrogen, which is set free, but immediately combines
with oxygen of the chamber to form nitrous acid, in
which state it accompanies the different gases into
the chamber E3, and thence by the tube E4 into the
large chamber FF, the two ends of which only are
shown in the engraving. A jet of steam in the tube
124 acts as a motive force in urging the gaseous
mixture into the chamber r, and also serves thoroughly
to mix them together, and so determine the chemical
reactions; 2 other jets 727a’ playing up into the
chambers produce similar effects. The gases which
escape these reactions pass by the tube as’ into the
chamber H, where they are also exposed to jets of
vapour e’ la. The gases which still remain unacted
on descend from the chamber 11 by a tube H’ H2, into
a close reservoir M, divided into compartments in
which the gases circulate and deposit their conden-
sable vapours. Near one end of this reservoir ascends
a pipe n3, which conducts the vapours into the
tambour n4, whence they pass by J into another con—
denser M’, and from this they are discharged by a
chimney into the atmosphere, the rate of discharge
being regulated by a damper.
By this last contrivance there is still a loss of
nitrous gas, which passes up the chimney. To prevent
this loss the waste gases are made to pass through
sulphuric acid of the density of 62° to 641° 13., which
allows the free nitrogen and oxygen to escape, but
absorbs the nitrous acid gas, which can thus be intro-
duced again into the chambers and exposed to the
action of sulphurous acid and vapour of water. To
effect these objects the gas, after having circulated
through the condenser M’, where it deposits its
moisture, passes into the chamber J'j, and ascending
through a grating steams up through a column of
coke which is kept wet by the continual dashing of
sulphuric acid-upon it. The sulphuric acid is supplied
by the‘ vessel 12, and is conducted by a pipe into a
kind of double trough Z balanced at its lower angle,
and. capable of oscillating between two pegs seen at j.
The trough is balanced in such a manner that one of
its divisions is always under the mouth of the pipe
which supplies the sulphuric acid; but no sooner is
one division filled with the acid than it tips over, dis-
charges its acid upon the coke, and brings the empty
division under the mouth of ‘the supply pipe; to be

in its turn filled and to tip over and discharge its acid
on the coke on the other side. In this way the acid
is dashed over the coke, which by its porous texture
exposes a very great extent of surface, and while
of the gaseous mixture which passes into the chamber
J’, the oxygen and the nitrogen escape by the chimney
0 into the atmosphere, the whole of the nitrous gas
is absorbed by the sulphuric acid, and is conducted by
the pipe which proceeds from the sloping bottom of
J’ into the reservoir J2, whence it is raised by the
pressure of. steam upon its surface into a cistern p,
which supplies‘ a reservoir q, and this in its turn dis-
charges ‘the acid by a funnel into a second double
trough g.’ balanced like the first 1 : from this trough
the. acid charged with nitrous vapour is dashed down
upon a sloping ' shelf 07, .whence ‘it pours down a
series .of- other sloping shelves, meeting in its way the
sulphurous acid-gas ‘from the furnaces Act, which,
accompanied by vapour from the steam jet c2, proceeds
in the direction of the arrows. The joint effect of
the steam and the high temperature is to disengage
from the cascade of acid a portion of its nitrous acid,
which in its turn converts a portion of the sulphurous
acid into sulphuric. The sulphuric acid newly formed,
as well as that from the cascade, is conducted by a
pipe into the chamber E’, where it disengages nitric
oxide, which gas in the presence of oxygen again
becomes nitrous acid, and'is'instantly hurried on with
the other gases and vapour into the other chambers, and
assists in the production of fresh portions of sulphuric
acid as already noticed. In this way by returning to
the chambers the nitrous vapours which formerly
escaped by the chimney, not only is the neighbour-
hood saved from the influence of the noxious caustic
rain which these vapours formed, but the manufacturer
saves above éfi-rds of the nitric acid, or of the nitrate
of soda or of potash which is required in the opera-
tion.1
We now return to the process as conducted in
Great Britain. A sulphuric acid house may be worked
day and night without intermission, or only for a cer-
tain number of hours. In the one case the chamber
must be supplied with a continuous current of fresh
air, because it is the air of the chamber which‘ sup-
plies the oxygen required to convert the sulphurous
into sulphuric acid, and not the nitrous acid gases
obtained from the nitric acid or the nitre,v these being
merely the media of transfer between the oxygen of
the air and the sulphurous acid. In the second‘ case,
or what is called the intermittent plan, the combustion
of sulphur is carried on for 2 hours; steam is ad-
mitted, and the whole left to settle for an hour and a
half : the conversion of the gases into acid then goes

(1) In Payen’s “Précis de Chimie Industrielle,” 1851, another
method of condensing the nitrous vapour is described. It consists
in passing the waste gases through a large series of bombaloes,
constructed and arranged somewhat like a Wouli‘e’s apparatus on
a very extensive scale. The bombaloes contain sulphuric acid,
which as it becomes charged with nitrous vapour is drawn off,
and returned to the chamber a’, and acid from the more distant
bombaloes is made to supply its place; fresh sulphuric acid being
poured into the bombaloes last emptied. M. Payen has shown
how the transfer of acid may be made self-acting by connecting
the bombaloes together by means of syphons. \
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l.
SULPHUR.
803
on for 3 hours, during which time the drops of strong
acid are heard rattling like hail-stones on the bottom
of the chamber. The chamber is then opened for
g hour, to admit fresh air and to prepare for another
charge. In a chamber of the capacity of 27,000 cubit
feet 9 cwt. of sulphur are burned in 24' hours. The
state of the interior of the chamber is ascertained by
openings in the roof, each covered with a glass bell.
When the interior of the glass does not appear thickly
covered with drops, the proportion of steam is in-
creased. A sample of the product may be taken out,
/ and the depth of the acid liquid
at the bottom of the chamber
ascertained, by means of an open-
ing in the side near the bottom
of the chamber, made by pushing
the lead inwards and prolonging
it so as to dip beneath the surface
of the liquid, as shown in Fig.
2121, and prevent the escape of
gas. The temperature of the chamber ought to be
maintained at 130° to 140° Fahr. If below 100°
the formation of sulphuric acid is liable to be sus-
pended, and a white crystalline compound to form on
the sides of the chamber. This is called by the French
“la maladie des chambres.” Indeed it has been sup-
posed that this crystalline substance must always be
formed and afterwards decomposed in order to pro-
duce sulphuric acid at all. It is formed by the union
of 2 equivalents of sulphurous acid (2SO2) with 1
equivalent of nitrous acid (N04) : but it separates into
2 equivalents of sulphuric acid (2S03) and 1 equivalent
of nitric oxide (N02), whence this white crystalline
substance has been named sulphate of nitric oxide.
But, however this may be, supposing the process to
be conducted successfully, the acid continues to be
formed and to trickle down the sides of the chamber
to the bottom, gradually increasing in density. When
the density of the acid varies from 1350 to 14:50 it
is drawn off from the bottom of the chamber by a
leaden pipe into large leaden boilers, where, by the
action of heat, a portion of the water of the acid is
driven off, and the strength of the acid thus increased.
These boilers are made of large rectangular plates of
thick lead, the edges being folded up so as to form
pans of the depth of 10 or 12 inches. Each boiler
rests on a close grating of strong iron bars, and has
a separate fire. As the acid in the top boiler becomes
stronger by the evaporation of the water, it is trans—
ferred by means of a syphon tube to the middle boiler,
and thence to the lowest. When the acid has ac-
quired the density of 1 650, or 1700, it must be
removed from the leaden vessels, because at a little
over this strength the acid corrodes lead. In order
to raise it to the commercial strength it must be con-
centrated in glass or platinum retorts, for which pur-
pose it is removed from the boilers into coolers, or run
through a long worm pipe surrounded by cold water.
When glass retorts are used, they are arranged in a
long gallery furnace in a double row, each retort being
placed in a sand-bath supported by fire-tiles and fur-


Fag. 2121.
nished with a separate fire. The vapour given off‘

usually contains some acid, especially when the con-
centration is nearly complete, and this vapour is con-
ducted into the chamber or into the leaden boilers.
In some sulphuric acid works near Salisbury, which
the Editor visited a few years ago, and described in
the second volume of his work on the “ Useful Arts
and Manufactures of Great Britain,” the glass retorts
were each of the capacity of at or 5 gallons, with the
necks fitting on separately like the top of an alembic.
The retorts were arranged in a double row of 16, and
while in operation the parts of the retort project-
ing from the sand-bath were covered
with a hood of tin plate. From 12
to 16 hours were required for the
concentration: this being completed,
the fires were extinguished and the
retorts left to cool; after which the
acid was drawn off into large brown
earthenware vessels by means of a
syphon of lead pipe, Fig. 2122, re- I
curved at the shorter arm. This Fi-‘I- 2122-
syphon was first inverted and filled with water; then
closing the long end with the finger, the short limb
was inserted into the body of the retort. On removing
the finger, the water in the syphon was set in motion,
bringing after it the acid. The water was caught in
a small cup held under the end of the syphon; this
flowed out with a gurgling sound, and the moment it
ceased the cup was removed, and the acid appeared;
it fell down into the deep jar in a full, smooth, quiet
stream, very much resembling oil, and reminding one
of the origin of the old name of oil oj'vz'z‘rz'ol, applied
to it from this circumstance. The acid was next
transferred into large globular green glass bottles,
called carboy/s, securely packed with straw in wicker
baskets. Each carboy contained from 80 to 100 lbs.
weight of the acid; the necks were closed with glass
or earthen stopples, luted on with clay or loam, and
tied over with coarse canvas. In this way sulphuric
acid is sent into the market. ‘
In the above works the glass retorts are found
to answer very well. No retort is ever disturbed
in its sand—bath while it remains entire; but when,
from exposure to draught or to too much heat, a re-
tort is cracked, it is removed at once, unless the crack
is situated in the upper part, where it admits of patch-
ing with white lead.
In large acid works, where the quantities produced
require the incessant working of the apparatus, this
system of gZuss-retortz'ug is not practicable. The
danger and great loss arising from breakage induced
the late Mr. Samuel Parkes to introduce stills of
platinum, a metal which resists the action of sul-
phuric acid even at high temperatures. The stills
are made of thin sheets of platinum soldered together
with pure gold :1 they are oval in shape, and of


(1) These stills are nearly all made in Paris, and are of the
capacity of from 5 to 20 cwt. ; they cost from 1,7001. to 2,6001. each;
and although one of these retorts wears out in two or three years,
yet it is found more economical in large works to use these costly
vessels than the cheap and abundant material, glass.
The following calculations by M. Payen prove that where glass re-
torts of the capacity of 80 litres do not cost more than 1 franc 60 cen-
3P2
5304
SULPHUR.
various sizes, and are preserved from the direct action
of the fire by being set in cast-iron ackets, arranged
over the fine of a furnace. The stills have platinum
heads and beaks like common stills, and the beaks
are inserted into leaden worms, in which the watery,
sulphurous, and nitrous acid vapours given ofi" during
the concentration are condensed and conveyed to the
water on the floor of the chamber. .
“Then the acid is sutliciently concentrated in the
platinum retorts, they are in some cases lifted off the
fire, together with their iron jackets, and let down
into a cistern of cold water. The boiling hot acid
is in this way speedily cooled; but this clumsy and
dangerous contrivance has been superseded in many
works by a platinum syphon, Fig. 2123, one leg of
which is twisted into a
worm, and contained in
a vessel of cold water v.
The acid is cooled in
passing through this
worm, thereby render-
ing it unnecessary to
disturb the retort. In
order to fill this syphon,
the shorter leg z‘ is
plunged to nearly the
bottom of the still; the
stop-cock c to the longer
leg, or worm, is closed;
the worm is filled with
cold acid through the
funnel f The stop-cock to this funnel is then closed,
and that at 0 suddenly opened; a quantity of acid
then flows out sufficient to rarify the small portion of
air in the upper part of the pipe, and to cause the hot
acid to rise over the bend, and thus produce a con-
tinuous stream. The flow of the acid can be regu-
lated by opening the stop-cock 0 more or less, and
a constant supply of. cold water may be kept up in
the outer vessel 'v by the pipe 20, which constantly
supplies colder and heavier water to the bottom of
the vessel v, while the water heated by the worm


Fig. 2123.

times each, as at Montpellier and the neighbourhood of large glass
works, then glass retorts and platinum are about equal inqcdsflt‘;
but when, as at Paris, Rouen, 8w, a glass retort of the capacity of
80 kilogrammes costs 6 francs, and can only be used on an average
5 times, thus yielding 400 kilogs. of concentrated acid, the addi-
tional charge on every 10.0 kilogs. ifor expense of retorts is_60
centimes at Montpellier, 8zc., and 1 franc 50 centimes at Paris,
Rouen, 850. In the latter case platinum is much less costly than
glass. For example, in a platinum-still the body weighs 63
kilogs. the capital 6 kilogs. the adjutages, gage, &c. 2 kilogs. the
syphon 10 kilogs.—making altogether 81 kilogs. and the cost
about 80,000 francs (3,200Z.). The interest on this sum, and the
wear and tear, may be represented at 24 francs per day. This sum,
spread over 4,000 kilogs., the quantity of concentrated acid pro-
duced daily by the platinum apparatus, causes an additional
charge of 60 centimes on every 100 kilogs. of acid; for—-
Kilog. Fr.
4,000 : 24
Kilog'. Cent.
100 : 60
Which shows an advantage of 90 cents per 100 kilogs. of acid‘ in
favour of platinum, when the retorts cost 6 fr. each; but when
the retorts cost only 1 fr. 60 cents each, the expense of platinum
and glass is the same, with the advantage in favour of platinum,
that it is not liable to break by the heat, as glass is, and so entail
loss of acid and danger to .the operatives.

escapes through the side opening at e. The platinum
retorts can be charged from 4! to 6 times a-day, which
gives them a great advantage over glass retorts.
The French method of concentrating the acid is
more elaborate than the English. It is conducted by
means of two leaden boilers or evaporators, B B’,
Fig. 2124:, and a platinum still P, as in the English
method; but the first of ‘the two boilers B is closed
in at the top for the purpose of passing a current of
sulphurous acid gas through the weak acid, and the
close cover to this boiler is supported by curtains or
partitions a a, which cause the sulphurous acid gas to
travel by a circuitous route, and thus multiply the
points of contact. The boilers are heated by the
fines of the fire F, and the lead is supported by an
outer casing of sheet iron, which also prevents the
flame from coming in contact with the lead. '
The acid to be concentrated is conveyed from the
sulphuric acid chambers by a leaden pipe 12, into the
boiler B, and when it has attained a certain height
therein it flows off by a waste-pipe. The sulphurous
acid gas mixed with atmospheric air is conducted into
the boiler from the furnaces Am in the steel engraving
by means of a pipe 8, Fig. 21241, and the gases which
remain after having circulated through the boiler,
together with vapour of water from the weak acid,
are returned by another pipe 8’ into the chimney c’ D,
and thence into the first chamber BB.’ of the steel
engraving. Within the chimney is shown a portion
of this pipe enclosing a steam jet X, which acts as
a moving power, setting the sulphurous acid gas in
motion from the furnaces Aw along the pipe 8, through
the boiler B in the direction of the arrows, then along
the tube 8' into the chimney D, and so into the
chamber 1313'. The sulphurous acid gas, mixed with
common air and assisted by the heat of the fluef”,
reacting on the nitrous and nitric acids contained in
the weak acid in the boiler, forms sulphuric acid, and
discharges by the tube 8' into the chamber E E’ nitric
oxide and nitrous acid, by which ,means the acid in
the boiler B is denitrified, and the nitrous products,
instead of being discharged into the air, are usefully
employed in producing the reactions above described.
The acid thus made stronger and purer is passed by
a waste-pipe or a syphon 0 into the open boiler B’,
which being nearer the fire F, is evaporated at a
higher temperature, and concentrated to about 60° B.
From this boiler the acid is passed into the platinum
still by means of a syphon 22, one leg of which is im-
mersed in a beaked vessel, on raising or lowering
which the discharge may be regulated or arrested
altogether. The concentration of the acid in the
platinum-still may be intermittent or continuous. In
the first case the platinum-still is filled ~2— of its capa-
city as indicated by a floating-gage g, fresh acid being
let in when the evaporation has lowered the surface
of the acid in the still about Ego-tbs of the depth of the
liquid. A brisk fire is kept up in r’, and the contents
of the platinum—still are made to boil until the acid is
suiiiciently concentrated: this'is known by the state
' of the acid water, which, distilling over from 1? in the a
state of .VaPOUJQ'lS condensed by the worm 2020 con;
SULPHUR.
8.05
tained in the refrigerator 3, and is received into- a
small reservoir lined with lead. The‘ liquor thus dis-
tilled over contains at first much water, and very little
acid, but in proportion as the acid- in P loses water,
its boiling point rises, more acid passes over, until at
length acid containing only a single equivalent of
water ($03,110) would pass over. When such acid
begins to pass over it is known that the contents of
the still have attained that degree of concentration;
___.
Fig. 2124..

but the process is nearly always arrested long before
this limit is attained, unless where acid of extra
strength is required, and which fetches a higher price
in the market. It is, however, a loss to the manu-
facturer to produce such acid, not only on account of
the smaller quantity which can thus be formed, but
on account of the extra consumption of fuel and the
high temperature, which towards the end of the pro—
cess is near 620°: this induces a great amount of ex-

ELEV'ATION OF BOILERS FOR. EVAPORATING SULPHURLC ACID.







pansion in the platinum, and endangers its cracking by
its subsequent contraction on admitting a fresh charge.
The operation is generally arrested when the condense
water is of the sp. gr. 4.56 B. The acid in the still
is then at 66‘.) B., and forms the sulphuric acid of
commerce.
The operationlis, however, more economical when
made continuous; for which purposev a constant stream
of acid is made to pour into the still 1?, and a constant
stream is at the same time being drawn off. In such
case the product does not mark a higher degree than
645° to 65° 13., and contains at least 1% equivalent
of water. By this plan, however, the level of the
acid in the still is kept constant, and the temperature
is always the same, two conditions which contribute
largely to the durability of the still. When the acid
is sufiiciently concentrated it- is drawn off by means
of the syphon aee’ d, one leg of which, we, is fixed
into the boiler r by a screw-joint, its open mouth
a nearly touching the bottom of B. When it is
required to draw off the concentrated acid this
syphon must be primed; for which purpose platinum


plugs are taken out of the platinum cups 6 e', and
strong sulphuric acid being poured into one of them
it gradually descends and occupies the long limb e’ (Z,
while the air escapes by the other cup c. When the
acid has risen up into one of the cups it is known
that the long limb is full. The two plugs are then
restored to their place, the cock K is opened, and the
acid flows down the long branch of the syphon, which
being immersed in a refrigerator B’ of cold water,
which is being constantly renewed, reduces the acid
to the temperature of the air, or thereabouts, and in
order to increase the cooling-surface the syphon is
divided into 2 or 4 branches. The acid is received
into carboys c e or into a reservoir of lead.
The sulphuric acid of,’ commerce is not quite pure.
It contains persulphate of iron and sulphate of lead,
and other fixed salts, some of which are deposited by
repose. In order to obtain it pure, as it is required
for many purposes of the laboratory, it must be
distilled, and the most concentrated portion of the
product reserved for use.
The ‘sulphuric acid which has hitherto been referred
806
SULPHUR;
to is the moozolzydrazfed, or one-watered acid ($03,110).
It has a very strong attraction for water, and mixes
with it in any proportion. As the mono-hydrated
acid, however, is much less volatile than water, (not
boiling below 600°,) these dilute mixtures may be
concentrated by boiling, which drives away the sur-
plus water, as already noticed. But by this method
the acid can never be made stronger than the mono~
hydrate, which boils at 620°, and distils without
change. Acid containing less water than this can
only be obtained by Valentine’s process of distillation
from vitriol, (as is practised at the present day in
obtaining what is called the Nordizausen acid ,-) and
the reason is, that the monohydrate, 803+H0, is a
chemical compound, having properties not interme-
diate between those of its ingredients.
drous, or waterless acid, SOs, which is a solid, is
extremely volatile, being entirely vapourized below
100° : yet, by uniting with 1 equivalent of water (the
boiling point of which is 212°), it forms a liquid that
does not evaporate below 600°. Compounds contain-
ing either more or less water than this, boil at lower
temperatures, but with this difference, that the former
give out only their surplus water, and the latter
only their surplus acid; so that, although boiling
strengthens the one, it weakens the other. At com-
mon temperatures, however, both kinds of acid be-
come weakened, but in diEerent modes; for while the
common acid emits no vapour whatever, but greedily
attracts moisture from the air, the Nordhausen acid
emits dry acid vapour, which, meeting with the moist-
ure of the air, instantly combines with it and con-
denses, forming the white fumes above mentioned;
and this continues until both the liquid and the
vapour (the former by losing acid, and the latter by
gaining water) become reduced to the state of mono-
hydrate, or common acid.
The N orclkausemlor fuming sulphuric acid, as it is also
called, is indeed a solution of anhydrous in the mono-
hydrated acid. If the Nordhausen acid be carefully
heated in a glass retort, it separates into .anhydrous
acid, which comes over in the state of vapour, and
monohydrated acid, which remains in the retort. If
these vapours be received into a small matrass with a
long neck [see Mx'rnxss, Fig. M26], surrounded by
a freezing mixture, they will condense under the form
of long, white, brilliant needles, and form masses
resembling asbestos. It fuses at about 77°, and
boils at between 86° and 95° ; its vapour is colourless.
It is so greedy of water, that if a small piece of the
acid be thrown into it, it produces a noise similar to
that of a red-hot iron plunged into water; the hissing
noise being produced by the great heat developed,
the instant formation of steam by the contact of the
acid and the water, and the condensation of the steam
by the cold water closing in upon the bubbles. Reg-
nault states that if a drop of water he allowed to fall
into a bottle of the anhydrous acid, a flash of light is
produced and an explosion. When the Nordhausen
acid is exposed to a low temperature, a white crystal-

(1)_ Nordhausen is in Prussian Saxony. The manufacture,
however, is chiefly carried on near Prague, in Bohemia.
The anhy- "

line substance separates, which is a hydrate contain-
ing half as much water as the common liquid acid.
For the preparation of the Nordhausen acid, iron
pyrites, or native bisulphuret of iron, are collected,
washed in water for the purpose of getting rid of clay
and earthy matters, and then calcined in clay retorts,
similar in composition to glass pots [see GLASS, Fig.
1056]. The object of this operation is, first, to obtain
sulphur, and secondly, to reduce the pyrites to that
friable condition which is favourable to the subse-
quent process. The pyrites contain 533?) per cent.
of sulphur, half of which may be obtained by distilla~
tionin close vessels; but in such case, the heat must
be sufiiciently intense to fuse the monosulphuret
which remains; but in so doing, the monosulphuret
penetrates the body of the retort, and quickly de-
stroys it. This inconvenience is avoided by employ-
ing less heat; but in such case only about 13 to 141
per cent. of sulphur is obtained, and there remains in
the retort a sulphuret of iron composed of F6283.
The retorts are arranged in double rows, six in each
row, and are heated by 3 to 6 fires, the whole ar-
rangement being similar to that of gas—retorts [see
GAS-LIGHTING, Fig.1020] ; and the vapour of sulphur
which is disengaged is passed down a wide tube into
cold water, where it is condensed. The residue in the
retorts is exposed in heaps to the action of the atmo-
sphere, and in the course of some years it undergoes
a slow combustion, the sulphur and the iron absorb
oxygen, the one forming sulphuric acid, and the other
oxide of iron: the combination of these two com—
pounds forms sulphate of iron, or green vitriol, which
is obtained by washing the pyrites with water, and
evaporating the solution. The mother liquors result-
ing from many similar operations are slowly evapo-
rated; they deposit a basic sulphate of peroxide of
iron, and retain in solution a mixture of sulphate of
protoxide and sulphate of the sesquioxide of iron. The
solution is evaporated nearly'to dryness, and is lastly
dried by the waste heat of the furnace, during which
operation the protosulphate becomes oxidized by ex-
posure to the air.
The furnace used in the distillation of the green
vitriol, is a long gallery, containing 2 or 3 rows of 100
retorts in each, (WW? A
heated by the 1 flame of a single
fire. Each retort
n n, Fig. 2126, is
about 8 inches in ‘
diameter, and 32 l '_
inches long, and a a,
- i,,_.-.,,l;-.ql--.|. n. {lnllr 1i,
communicates with a receiver 0 / / ”
of the same capa- Fiy- 2126-
city, and of similar form. 200 retorts in the course
of 418 hours, during which about 1% ton of lignite is
burnt as fuel, decompose about 560 lbs. of green
vitriol. Vapour of water is first disengaged, and
this is allowed to escape; then sulphurous acid and
oxygen; and after these sulphuric acid, partly anhy-
drous, and partly hydrated, which is collected. About








lg‘: _
a’ 4m‘


SULPHUR.
‘807 i
225 lbs. of this mixed acid is thus obtained, and
about 282 lbs. of peroxide of iron or colcothar re—
main in the retorts.
Of late years a similar acid has been obtained in
France, by distilling dry bisulphate of potash, or of
soda, in earthenware retorts. .
The chief use of the Nordhausen sulphuric acid is
to make the solution of indigo so much used in dyeing
blue colours. 4t parts of the fuming sulphuric acid
dissolve 1 part of indigo, which is soluble in not less
than 8 parts of common sulphuric acid; not only is
the excess of acid lost, but its presence exerts an
injurious action on the dye studs, and the articles to
be dyed.
Iron pyrites is also used in the manufacture of
ordinary sulphuric acid, as a source of sulphur, for
the production of sulphurous acid. It is applied in
two ways : in the first, the pyrites are washed at the
stamping mill, and then spread in layers of about
2 inches deep, on plates of iron heated to redness,
in a furnace similar to that shown at A or a of the
sulphuric chambers, represented in the steel engrav-
ing. The pyrites is frequently stirred with an iron
rake, for the purpose of renewing the points of con-
tact with the draught of air; and after 6 hours the
charge is let down into a cavity under the furnace,
where it continues to burn for some time, and fur-
nishes sulphurous acid, which passes up the chimney
c’ n, and so into the chamber E’.
In places where fuel is scarce, the second plan is
adopted, viz. to make the sulphur of the burning
pyrites serve as fuel to a new charge. For this
purpose a kind of running kiln, Fig. 2127, is used;
a fire is lighted on the hearth sufiicient to raise the



interior of the furnace to a red heat; the first charge
of pyrites, 1°, previously reduced to small lumps, is
then filled in through an opening 0 in the top, and
as it becomes ignited, fresh quantities are gradually
added, until a height of nearly 3 feet is attained. The
supply of air is regulated by the sliding door 1), and
as the pyrites is thoroughly burnt, they are hooked
out by means of a long iron rod from between the
bars, and they fall into the ash pit below. As the
charge sinks in the furnace, more pyrites is added
through 0. Six of these furnaces are arranged round
a central shaft, into which they discharge their pro-
ducts of combustion, consisting chiefly of sulphurous
acid and air, by channels such as t, and from the

with sulphurous acid. For further details we must
refer to Payen’s “ Chimie Industrielle.”
In addition to sulphurous acid, S02, and sulphuric
acid, S03, sulphur and oxygen combine in other pro—
portions. Hyposulphurous aez'djS2Og, is interesting,
from the property of hyposulphite of soda dissolving
certain insoluble salts of silver, such as the chloride,
on which account it is of importance in PHOTOGRAPHY,
as noticed in that article. The acid has hot been
isolated, but by digesting sulphur with a solution of
sulphite of potash or soda, a portion of sulphur is
dissolved, and the liquid by slow evaporation yields
crystals of the new salt. Hyposulphurz'e uez'cl, S505,
Sulphuretted hyposulphurz'e uez'd, S305, and Bisulphu—
rett‘ecl hyposuZphu-rz'e acid, S405, do not require further
notice in this place.
Sulphur combines with hydrogen, forming sulphu-
rezftecl hydrogen, or hydrosulphurz'e uez'rl, HS. It is
a frequent product of the putrefaction of organic
matter, both animal and vegetable; and it occurs in
certain mineral springs. It is readily prepared in a
gas bottle, such as is used for making common hydro-
gen, by the action of dilute sulphuric acid on sul~
phuret of iron, or of dilute hydrochloric acid on
sulphuret of antimony. The action will be understood
in either case from the following diagrams :—
Sulphuret of iron _ \ Sulphuretted hydrogen.
.\
Hydrogen
Water’...nunuun¢{oxygen \u Sulphuric acid "— ‘ oxide of iron. _
Hydrochloric acidgéllyldfiplggn Sulphuretted hydrogen.
Sulphuret of an- Sulphur
timony .......... .. Antimony iChloride of antimony.
Sulphuretted hydrogen is a colourless gas, with an
offensive odour resembling that of rotten eggs; a
minute portion of it is sufficient to taint the atmo-
sphere of a large room. It is instantly decomposed
by chlorine; a small quantity of which, as evolved
from chloride of lime by itself, or by the addition of
a little dilute muriatic acid, will instantly clear a room
of the sulphuretted hydrogen present. Sulphuretted
hydrogen is not irritating, but narcotic; it is highly
poisonous; an atmosphere containing 150th of it, is
sufficient to kill a dog, and filo-6th of it will destroy a
bird. Men employed in emptying cesspools are some-
times seized with asphyxia, from the presence of
this gas. The best remedy is to pour a little strong
vinegar in a plate, and sprinkle upon it powdered
chloride of lime, and hold this under the nostrils of
the patient. Sulphuretted hydrogen burns with a
blue flame, the results of combustion being water
and sulphurous acid; its sp. gr. is 1171, air being
1000, and 100 cubic inches of it weigh 36'33
grains. It becomes liquid under a pressure of 17
atmospheres at 50°. Cold water dissolves from 2%,
to 3 times, and alcohol 5 to 6 times its own volume
of this gas, and the aqueous solution reddens litmus
paper. The solution is a most useful test, but it
cannot be preserved, as the oxygen of the air soon
spoils it; it is therefore best to make it as it is
wanted, for which purpose a small bottle, with a bent

central shaft the sulphuric acid chambers are supplied tube in its cork, is supplied with sulphuret of iron
808
suLraua-sunvnrrrm.
and water, and when required for use, the addition of
a few drops of sulphuric acid will evolve the sulphu-
retted hydrogen. The bottle must be emptied when
enough gas has been obtained for the purpose re-
quired. “There are few re-agents,” says Mr. Fownes,
“ of greater value to the practical chemist than this
substance; when brought in contact with many me-
tallic solutions, it gives rise to precipitates, which are
often exceedingly characteristic in appearance, and it
frequently affords the means also of separating metals
from each other with the greatest precision and cer-
tainty. The precipitates spoken of are insoluble
sulphurets formed by the mutual decomposition of
the metallic oxides or chlorides, and sulphuretted
hydrogen, water or hydrochloric acid being produced
at the same time. All the metals are, in fact, preci-
pitated, whose sulphurets are insoluble in water, and
in dilute acids.” The best test for the presence of
sulphuretted hydrogen, is paper wetted with a solu-
tion of acetate of lead, which is blackened by the
smallest trace of the gas.
Btsutplturet of ouroou, (382, is formed by passing
the vapour of sulphur over red hot charcoal, in a
porcelain tube; or by distilling 6 parts of yellow iron
pyrites with one of charcoal. The product is col-
lected in a receiver cooled to 32° or lower, and should
be purified by re-distillation at a low temperature,
with chloride of calcium; it then forms a transparent,
colourless, highly inflammable liquid, of great refrac~
tive and dispersive power; its density is 1'272; its
boiling point 110° Fahr., and it emits vapour of con-
siderable elasticity at ordinary temperatures; it pro-
duces a very low temperature by its evaporation,
[especially in vacuo where ——80° has been obtained by
its means; it does not itself freeze at —-60°; it has a
pungent taste, and a peculiar foetid odour. It dis-
solves sulphur‘freely, and deposits it on evaporation
in beautiful crystals. It also dissolves phosphorus in
large quantity, and the solution is sometimes used to
give a thin film of phosphorus to delicate articles in-
tended to be coated with metals. [See ELECTRO-
METALLURGY.] The chief demand, however, for
bisulphuret of carbon, is as a solvent of india rubber,
for softening that substance, and also for vulcanising
it. [See Gxourcnouo] Hence the demand for
bisulphuret of carbon has of late years greatly in-
creased, andto meet this demand it is manufactured
on a large scale, the apparatus for which, by M. Pe-
roncel, is described in Payen‘s “ Chimie Industrielle.”
C/ztorz'ete of sulphur, SCI, also used in the vulcaniza—
tion of india rubber, is prepared bypassing drychlorine
over the surface of sulphur, melted in a glass retort.
The chloride distils over into a cooled receiver, as a
mobile liquid of a deep orange yellow colour, and
disagreeable odour; it is decomposed by water; and
as it dissolves both sulphur and chlorine, it is. not a
very definite compound. A peroittorz'rle is formed by
exposing the chloride for a considerable time to the
action of chlorine.
SULPHURATION.—-See SULrnUn.
SUMAGH.-—See LEATHER.
SURVEYING. The art of ascertaining and re-

gistering ‘the horizontal extent and forms of any parts
of the earth’s surface, whether of land or water, and
whether bounded by natural features, human works,
or conventional lines. No art has been so prolific in
giving birth to science as this, for the whole range of
mathematical, z'. e. of exact, knowledge and workman-
ship has ever hinged on the advance of the chief
branch or rather trunk of mathematics, the name of
which, geometry, to this day indicates its original pur-
pose, taucZ-measuremeut ,- and it is the extension of
this word geometry to designate the whole resulting
science that has necessitated the new word suruegz'ug
to take its place as the name of the parent art. So
that surveying now means what geometry primarily
meant.
That this art began in Egypt is commonly believed
and hardly to be doubted, since not only did the
yearly inundation in that country interfere with the
protection of artificial boundaries, but it was the first
valley that required them 5 agriculture having there
first come to occupy the whole available land, and
therefore first led to the exact division and appropria-
tion of it ; at one time (as we learn from the book of
Genesis) in the hands of the people at large, and
afterwards, by a special intervention of Providence, so
centralized in the monarch, as to enable the prophet-
statesman, by a lasting charter and by one measure, to
perpetuate at once strength of government and cer-
tainty of supplies, with popular immunity from ex-
tortion. To this day Egypt consists entirely of crown
land, inalienable and yet unchargeable with more or
less than a fixed portion of the produce: not indeed
the same that at once left the poorest worth cultiva-
ting, and checked individual avarice by the unprofit-
ableness of sub—letting; but the 20 per cent. (Gen.
xlvii. 24,) is known to have continued in its integrity
down to the times of the Ptolemies; and of course
the due assessment of this Josephian tax necessitated
and powerfully advanced this art, the mother of so
many sciences.
Hence it was in Egypt, by observations of latitudes
at the two ends of the country, and estimation of the
distance in furlongs, that the first and only ancient
attempt to settle the curvature (and hence the size)
of the globe, was made, by Eratosthenes, about
230 13.0. This problem, however, the utmost triumph
of surveying, and which calls together all its latest re-
finements, could not be performed with any certainty
until within the last century.
In England, the measurement of land is performed
with a measure called after its inventor, Guuter’s efiaz'u,
contrived to simplify the computations as far as our
peculiarly clumsy traditional units of area and length
would admit. The smallest, indeed, of the three units
of area used for land, the perc/z, is the square of one of
our units of length, the rod or pate ,- but the two higher
ones, the road and acre, correspond to the squares of no
lineal measures. The acre, however, being a tenth of
a square furlong, and therefore, when disposed in a
strip one furlong in length, requiring to be a tenth
of a furlong wide, determined this latter fraction as
the most convenient length for the chain, and it ‘com
SURVEYING.
809
tains exact though awkward numbers of all the lesser
units, viz. a rods or poles, = 22 yards, : 66 feel, :
792 inches. Its length is then the 80th of a mile, or
10th of a furlong; and its square the 10th of an acre.
2% such squares are a road or quarter acre, and the
40th of this, or square of a quarter-chain (i. e. such a
square as the chain will go round) is a perch, or square
rod or pole, the smallest unit used for cultivated land.
A division of this chain into feet would evidently
fail to mark the pole, which is 16;; feet. Moreover,
the relations of the yard or foot to the areal measures
(4810 square yards : 43560 square feet in an acre,
and 272%- square feet in a perch,) are so absurd, that
a chain thus divided would necessitate about 5 times
the natural amount of calculation for finding areas.
Although some chains, such as are used for distance—
measuring alone, have 132 half—foot links, (which are
a convenient length for uniting lightness and stiff-
ness,) the proper chain is divided into 100, so that all
the measurements may be expressed in one denomina-
tion, linhs, and by simple omitting the last two
figures, the chains are seen, thus: 2135 links :
21 chains, 35 links. And as all calculations of area
thus lead to a result in square linhs, which are a
10,000th of a square chain, or 100,000th of an acre,
they show at once, by omitting their last five figures,
the acres; and the five figures cut off, if multiplied
by 4, show, similarly omitting the last five resulting
figures, the odd roods if any; and the five cut ofl
from these, again multiplied by 44, give, omitting the
last four of the result, the odd perches. The four
out off to leave this are decimals of perches.
The linh, then, is a measure of 7'92 inches, only
introduced for the sake of abridging calculation. Be-
tween each two links are one, two, or three small
rings, according to the degree of flexibility desired in
the chain; and for rough work it should have 200
half-links, to avoid risk of bending them. The middle
of the chain is marked by a round piece of brass, the
40th link from each end by a four-fingered bit; the
30th, 20th, and 10th, by a triple, double, and single
finger respectively; and the 25th by some other
mark; which renders the counting of odd poles or
links a momentary operation. The chain can be
pulled on almost any ground perfectly straight, and
the follower of it can direct him who leads, to place
a pin in the straight line with the mark towards which
they are proceeding; or, in continuing a previous line,
the leader can place it himself correctly by the marks
defining that previous line. He has at starting 10 of
these pins, which the follower picks up as they are
left, so that at the end of every furlong they must be
retransferred to him, and an entry of 1,000 made in
the book (all numbers in which are understood to be
links). As horizontal distance only is to be measured,
and it is hardly possible to stretch a whole chain
straight in the air, sloping ground must be measured
by half or quarter chains at a time, unless the slope
be regular enough to enable its inclination to be mea-
sured by some kind of mason’s level, and a reduction
made from the length along the ground, by a table
which shows the reduction per 1,000 links for given

degrees of slope (ie. the versed sine of those degrees
to a radius of 1,000). But the difference between hori-
zontal and inclined distance, especially on slight hills,
is always far less than we are led to estimate it.
Surveying should first be learned with the chain
alone, and the most elementary subject, a single en-
closure, with four straight sides, may always be thus
mapped by measuring each side and one diagonal. It
is obvious that these five dimensions, transferred to
paper, will give one definite figure only; and this
operation is called plotting it. A perpendicular to
the diagonal, AB, Fig. 2128, must then be dropped


Fig. 2128.
from each of the other angles, and measured by the
scale which is used for plotting; and half the sum of
these, multiplied by AB, gives the area of the two tri-
angles whose common base is AB, that is, of the
whole field. It is plain, that any figure of straight
sides, however complex, can similarly be divided into
triangles less in number than the sides by two; and
every side of, each triangle being measured in the
field, their perpendiculars can be measured on paper.
For a curved boundary, however, it is necessary to
measure a straight line as near it as may be conve-
nient (which, in a simple curve, will resemble a string
to a bow), and make this straight line, which need not
always have its extremities at corners of the field, a side
of one of our triangles, and while measuring it, to take
also a series of distances from different points of it to
the curve. These are called ofisets, and must be perpen-
dicular to the straight line, which maybe ensured nearly
enough by eye, if we measure them with rods placed
against the chain without disturbing it. One must be
carried to every sudden bend or break in the curve; but
if it have none, they will be best repeated at regular
intervals of a chain, or more or less, according to the
exactness desired. In either case, the number of links
from the beginning of the line at which each is placed,
must be noted, as well as its length. We have then
plainly the means of plotting as many points of the
curve as there are offsets, and through these points
its map may be drawn, as shown in Fig. 2129. The
area, then, of each space between two offsets, is taken
as if the line joining their ends were straight, whence
the necessity for placing one at every decided break.
It is found by multiplying the half sum of the two
offsets by their interval. Where any number of inter-
vals are equal, it will easily be seen how the whole
810
SURVEYING.
area for that length can be abridged into one opera
tion. The whole offset space is then added or sub-

l
/
Fig. 2129.
tracted, according as it lies without or within the
triangulation of the field. ,
These two principles embrace the whole practice of
area computing, and no other can ever be necessary.
Moreover, means of registering all this, and all things
necessary to plotting a finished map, without sketch-
ing any map at all, have been contrived as follows:—
Each page of the field-book is divided into 3 columns,
and we begin at the hollow of the middle one, in which
J we note progressively upwards all measures and me-
moranda relating to the lines along which we chain.
We call the starting-point A; the end of the first line
chained, or beginning of the second, B, and so on;
that, as each turning-point has a separate letter, it
may be known when we have returned to a point
visited before; and at the end of every line we note
by one of two marks, such as r or Z, whether our
turning into the next line be to the right or left. The
two side columns are reserved for the lengths of offsets,
which we write to the right or left, according as they
lie with regard to the line along which we are chain-
ing; and hence the reason for adding our notes up-
wards from the bottom of the page. Any memoranda
of objects passed are also written in the right or left
columns.
There is no difficulty in extending this method to
several adjacent enclosures or a whole district, only
observing that the longer our straight lines the better
and more exact will the work be, so that the principal
ones should, in this case, be quite independent of
fences or boundaries, (unless some remarkably long
straight pieces thereof should lie conveniently for the
purpose,) and should be extended without a turning
as far as possible within the limits of the survey.
Every fence crossed must be noted in the middle
column, with the number of links at which it occurs.
It is further to be kept in mind that all triangles are
plotted more exactly the nearer they approach to
equilateral ones, so that the largest especially must be
as nearly so as circumstances admit, and are ill-cou-
dz'lz'oued in exact proportion as their angles differ more
from 60°. _
The simplest instrumental aid beyond the chain, is
some means of finding the spot in any line from which
a perpendicular thereto will reach a given distant
point. The saving of measurement by this will
appear by considering that in Fig. 2128, ‘(the only
use of chaining AC, 033, being to define the place of
0,) if we could know in the field on what point D, of
the chained line AB, a perpendicular to it from 0
would fall, we should only have to measure this per-
pendicular, instead of the two lines AC, on, both
longer than itself. Three lines instead of five would
thus suffice to plot and thoroughly survey the whole

field; and further, as the perpendiculars, and not the
sides, are directly influential on the area, it would be
more satisfactory to measure them in the field than
on a paper plan. The oldest expedient for this is the
oross-slafl, whose simplest form has for the head a
mere board with two deep saw~cuts across it at right
angles; accuracy depending of course on the square-
ness of these angles. This being planted in some part of
AB, and so turned that through one of its grooves we
can see A in one direction and B in the other, we
shall through the other groove see to the right or
left of c, and must accordingly move the staff forward
or backward along A 13, until by a few trials we find
the spot where it will permit the three marks AB 0 to
be seen. This has been superseded, however, by the
optical square, a far more elegant and expeditious
instrument, which need not be more expensive, and
may insure more accuracy than any cross, however
large, while it may be made so small as to be carried
in the waistcoat pocket. It consists of two plane
pieces of silvered glass, immoveably fixed in a sort of
box in that position which the glasses of a sextant
have when its index is at 90°, viz. inclined 45° to
each other. Half the silvering of one glass being
removed, the eye directed to it sees at once an object
directly in front, through the transparent portion, and
another object reflected from the other glass to this
one and thence to the eye; and this object must be
90° distant from the former; so that by walking
along the part of an where we expect the perpendicular
to fall, with the instrument at our eye, and A in sight
through it, various objects about 0 will. successively
appear reflected, and when the image of c itself
becomes coincident with A, we are at the right spot.
Single fields, and even the main features of a large
district, as far as they are visible over each other, (as
in hills surrounding a plain, or lower country sur—
rounding a flat-topped eminence,) may also be plotted
with moderate accuracy by measuring only one line
upon the central plan, or central elevated platform,
and setting up, first at one end thereof and then at
the other, a plauo table or drawing-board with paper
on it. A ruler must be provided with two sights or
vertical slits in plates of metal, with a hair or hair
wire stretched upright in each, exactly over the
drawing edge of the ruler, which edge must be kept
against a fine needle stuck in the drawing-board, and
turned about so that the various objects whose places
are to be plotted may be successively seen through
the sights and in a line with the two wires. When
so seen, a line is drawn towards them from the needle,
by the edge of the ruler. The table being moved to
the other station, the needle is also moved a space
representing on the scale of the intended map the
measured distance of the two stations apart. The
table being first set so that the line towards the
former station is correct, all the same objects are
again observed, and it is plain that the lines radiating
to them from the new place of the needle will meet
the former lines at the true places of those objects
on the map. '
This is in fact a zfrz'gouoflwlrz'oal survey, in so far as
SWEEP-WASHING—SYNTHESIS—~SYRINGE.
811
it is not only by measurement of z‘rz'aezgles, as every
survey is, but depends on the observation of their
angles, instead of their sides, of which only one, the
common base of all the triangles, is measured. The
angles, indeed, are not measured, but only transferred
from the ground to the paper, where they could then
be measured with a common protractor if necessary,
which, however, it is not, for computation of areas
or any other purpose. Now the advantage of mea-
suring the reed angles by a graduated instrument,
(2'. e. a protractor of the utmost possible delicacy,) is
not to obtain a more exact plot, (for this will always
be limited by the delicacy of the protractor used on
the paper,) but to make the ascertaining of all the
unmeasured lines, and hence of the areas, independent
of the plotting altogether; to make it matter of com-
putation only, from the tables of trigonometrical
ratios, which may be carried to any degree of minute-
ness. In proportion to the accuracy attained in the
measurement of the angles, is the number of triangles
that may be attached to each other, and hence the ex-
tent to which a single survey may be carried from one
measured base; for the principal or first order of tri-
angles are of course made as large as the situation of
hills will permit, their angles being on the chief emi-
nences, and often more than 100 miles apart.
The instrument now exclusively used, we believe,
by Englishmen for these measurements, is the THEO-
DOLITE,——-WlllCl1 see.
SUSPENSION BRIDGE—See BRIDGE, Sect. V.
SWEEP—WASHING is the art of recovering the
particles of gold and silver out of the sweep or ashes,
earths, sweepings, &c. of the jeweller’s workshop. In
making a wash, the old crucibles, and even the bricks
of the furnaces, are pounded for the sake of the mi-
nute portions of precious metal which they may con—
tain. The water in which jewellers wash their hands
is collected in a tub : the dirt and mud settle by
repose, and the water above it is drawn off every few
days, and when a sufi‘icient quantity of sediment is
collected the tub is carried ofi' in the sweepwasher’s
cart.
The various refuse collected by the sweepwasher
are well ground and mixed together, and are then put
into large wooden basins, and washed several times,
and in several waters, which run off by inclination
into troughs at a lower level, carrying with them the
earthy substances and the finest particles of metal,
leaving behind those which are visible to the eye and
can be taken out by hand. The finer parts which pass
away with the earthy substances are recovered by
means of mercury and a washing-mill. The mill
(which is similar to that described under METAL—
LURGY, Fig. 1451) consists of a large wooden trough,
at the bottom of which are two metal portions, the
lower of which is convex, and the upper, which is in
the form of a cross, concave. At the top is a winch,
placed horizontally, by which the upper piece is made
to rotate, and at the bottom is a hole closed by a
hung, for letting out the water and earth when suffi-
ciently ground. In having a wash, the trough is filled
with water, 80 or 40 lbs. of mercury are poured in,

and 2 or 3 gallons of the matter remaining from the
first lotion. The winch is then turned, and the upper
mill-stone, by its revolutions, grinds the sediment and
the mercury together, and the particles of gold and
silver are readily dissolved by the mercury. This
work is continued for 2 hours, when the bung is re-
moved, the water and earth run out, and a fresh
quantity admitted. The earthy substances are usually
passed 3 times through the mill : the mercury is then
taken out, washed in several waters; put into a tick-
hag, pressed to get rid of water and loose mercury;
the remaining mercury is sublimed, and the alloy of
gold and silver is parted with nitric acid. See
Assume.
Two or three of the washing-mills may be worked
together at different levels, as noticed under GOLD.
Mr. Gill states, that “ a mill was established at Geneva
for washing the goldsmiths’ and jewellers’ sweepings
gratis. It consisted of a flat circular ring of cast-iron,
placed horizontally, and having a circular groove or
channel, in which 2 heavy cast—iron runners were
made to turn by the power of horses. The sweepings
being put into the channel with mercury, water was
made to enter the channel on one side and pass off on
the other side continually during the action of the
machine. We said the proprietors professed to grind
the sweepings gratis; but, in fact, the water carried
off with it into proper receptacles placed in an adjoin—
ing room so much gold, as to render the concern a
highly lucrative one. If we are not mistaken a simi-
lar machine is, or at least was, established byeforeign-
ers in London some time since.” 1
SWELL. See ORGAN.
SYNTHESIS (aim and de'o-ts, putting together),
aterm applied to that chemical action by which bodies
are united into a chemical compound. Under ANA-
LYSIS it was shown that alum consists of alumina,
potash, sulphuric acid, and water; the same thing
may be shown by synthesis, for by combining these a
constituents in proper proportions, alum is produced.
Thus the chemist is doubly satisfied with the correct-
ness of his analysis when he can reproduce the body
analysed by synthesis. This, however, he is not able
to do in all cases; for there are a large number of
bodies, especially the organic, which cannot be pro-
duced synthetically.
SYRINGE, a pipe or tube (mipryg), so arranged
as to draw up a liquid and then inject it with violence.
A syringe is only a single acting pump, and the water
ascends in it on the same principle as in the common
pump. [See PUMP, Fig. 1772.] For particular pur-
poses syringes have some special construction, as in
garden syringes, which are often of large size, jets are
provided ‘for the purpose of scattering the water in
the form of fine rain. The syringes used in surgery
are often carefully and accurately made, so as not to
entangle air with the liquid drawn up, and to inject
the latter with a regulated velocity. The stomae/z-
pump is a syringe, with a flexible tube attached,
which is passed into the stomach of the patient, with

(1) Technical Repository, vol. viii. 1826.
812
TABB YING—TALC—TAMARIND—TANTALUM—TAPIO GA.
and massive talc, &c.
a guard for fixing between the teeth to preserve the
tube from injury: a branch pipe is also attached to
the syringe, for supplying it with liquid from a vessel
when the syringe is used for injection, and to provide
a channel for the escape of the liquor when the syringe
is employed to empty the stomach. The valves are so
arranged that the instrument will act either way. It
is usual, first, to inject a diluent into the stomach, and
then to pump it back again together with the matter
which it is desired to remove. Or a fluid may be
injected 'into the stomach until it is involuntarily dis-
charged by the mouth, and the operation is continued
until the fluid is no longer contaminated. The err-
kaustz'rzg and coucteusz'ug sgrz'uge for aeriform fluids is
described under AIR, Fig. 19.
SYRUP. See SUGAR.
TABBYING, a variety of CALENDERING, in which
the rolls are engraved so as to impart to the silk or
stuff the effect of waves, from the unequal action of
light on the fabric, so that the rays are very unequally
reflected.
TACK. See NAIL.
TAFFETY, or TAFFETA, a silk stuff, smooth and
glossy, plain, coloured 01' striped with gold, silver, &c.,
chequered, flowered, &c. See WEAVING.
TALO is one of the hydrous silicates of magnesia.
[See MAGNESIUM.] It occurs crgstattz'zect and massive.
The primary form of the crystal is a rhomboid, but it
usually occurs in the secondary form of hexagonal
laminae, and even in long prisms. The cleavage is
distinct and perpendicular to the axis. ' It is readily
separable into thin plates, which are flexible, but not
elastic. The lustre is pearly, and the colour a shade
of light green or greenish white: sometimes it is
silvery-white, and also greyish-green and dark olive-
green. It is unctuous to the touch, and is easily
impressed by the nail,-—the hardness being equal to
1 or 1'5 : the density varies from 2'7 to 2'9. Crystal-
lized talc occurs in small quantity in serpentine rocks,
accompanied by carbonate of lime, actinolite, steatite,
The massive varieties occur in
beds of micaceous schist, gneiss, and serpentine.
Massive talc or soap-stone reduced to powder forms
what is called boot-powder. Bootmakers dust the in-
side of a tightly fitting boot with this substance to
enable it to be drawn on easily. This substance was
largely used some years ago at Manchester, as one of
the ingredients for converting an inferior low-priced
tea into a high-priced one. The manufacturers of
boot-powder, surprised at the large demand for their
article by one house, and that house a tea-ware-
house, made some inquiries, which led to sulficient
publicity to put a stop to the fraud. See TEA.
Iuduratecl talc occurs in primitive mountains, in
clay-slate, and serpentine; it is massive, of a greenish
grey colour; the structure schistose and curved; it
is of a shining and sometimes pearly lustre; trans-
lucent, soft, and rather unctuous to the touch, and of
the sp. gr. 2'9.
Lamellar talc contains, according to Vauquelin, silica
62 per cent. magnesia 2'7, alumina 1'8, oxide of iron
3'2, and water 6. Nearly allied to mica, are steatite, l

chlorite, and other magnesian minerals. See MAG-
NESIUM—STEATITE.
Tatcose state resembles mica slate [see Mica],
but has a more greasy feel from. its containing talc
instead of mica. It is of a light-grey or dark-grayish
brown colour; it breaks into slabs, which are used for
fire-stones. Talcose roe/e is a kind of quartzose granite,
containing more or less talc: it is intersected by
veins of white quartz, and also contains chlorite.
“ The talcose rocks,” says Dana, “are, to a great ex-
tent, the gold-rocks of the world. This rock contains
the topaz of Brazil, and also euclasc, and many other
minerals.”
TALLOW. See CANDLE—OILS and FATS.
TAMARIND, the fruit of a tree (Tamarz'mtas
Imtz'cus) growing in the East and West Indies to the
height of 30 or 40 feet. When the fruit is ripe the
shell or epicarp is removed, and the fruit placed in layers
in a cask, boiling water being then poured over it.
Another plan is to put alternate layers of tamarinds
and powdered sugar in a stone Tamarinds are
imported both raw and preserved. Tamarind pods
are from 3 to 6 inches long, and more or less curved:
they consist of a dry, brittle, brown external shell,
within which is the acidulous, sweet, reddish-brown
pulp (which is the useful part) penetrated by strong
fibres. Within this is a thin membranous coat enclos-
ing the oval brown seeds. The pulp as analysed by
Vauquelin contains citric acid 9'40, tartaric acid 15 5,
malic acid 0'45, bitartrate of potash 3'25, sugar 12'5,
gum 4:‘7, pectin 6'25, parenchyma 34'35, and water
27 '55. The pulp allays thirst, is nutritive and
refrigerant, and in full does laxative. “ An infusion
of tamarinds,” says Pereira, “ forms a very pleasant,
cooling drink, as does also tamarind whey.” Infusion
of senna with tamarinds is a useful laxative.
TAMPING. See STONE.
TAN. See LEATHER.
TANNIC ACID. See LEATHER.
TANNING. See LEATHER.
TANTALUM (Ta 185,) also called COLUMBIUM, a
rare metal found in combination with the oxides of
iron and manganese, and also with yttria in the
Swedish minerals taatatz'te and gttro-taatatz'te. The
metal has been obtained in the form of a black powder
resembling iron; its sp. gr. is about 6. The oxides
have acid properties: tautatous aetct contains Ta 02,
and tautatz'c or eolumbz'e aoz'ct, Ta. ()3.
TAP. See SCREW.
TAPESTRY. See WEAvme.
TAPIOGA a form of STARCH, prepared in South
America from two species of Jautp/za, or the (litter
and sweet cassava or maaz'oc roots. From the facility
with which the bitter cassava can be rasped into
flour, it is cultivated almost to the exclusion of the
sweet variety, which contains in its centre a tough
fibrous ligneous cord, which is absent in the bitter
variety. The latter, however, contains a highly acrid
and poisonous juice, which is got rid of by heat or by
fermentation, so that the cassava bread is quite free
from it. When the juice has been carefully expressed,
the fecula or flower is washedand dried in the air
*traa'rxmc ACID.
813 i
without heat, and _forms the Brazilian arrow-root of
commerce; but when dried on hot plates it becomes
granular, and forms tapioca. An artificial tapioca is
made with gum and potato starch: the granules of
this are larger, whiter, and more brittle, and more
soluble in cold water than genuine tapioca. See
Srxncn, Fig. 2018.
TAR. See Tunrmv'rnvn.
TARTAB, or ARGOL, is an impure tartrate of
potash, deposited from grape-juice in the act of fer-
mentation, and forming a crystalline incrustation in
wine casks. See WINE.
TARTABIC ACID is the acid of grapes, tamarinds,
the pine-apple, and several other fruits in which it
occurs in a free state. It also exists as tartar in
grapes, tamarinds, mulberries, samphire, &c. ; in the
roots of wheat and of dandelion, in the berries of
sumach, and in the rhubarb plant, the potato, and
Iceland moss; it exists in the form of tartrate of
lime in squills, madder root, quassia wood, the fruit
of Rhns typhinnm, and the tubercles of Helianthns
tnherosns. Tartaric acid is prepared by dissolving
tartar in hot water, getting rid of the colouring matter
of the wine by means of pipe-clay or animal charcoal,
and crystallizing. This forms cream of tartar, and is
used in preparing tartaric acid; for which purpose it
is dissolved in boiling water, and powdered chalk
added until efl’ervescence ceases, or the liquid is no
longer acid. Tartrate of lime and neutral tartrate
of potash are formed, and can be separated by filtration,
as the tartrate of lime is insoluble. _The remaining
solution of tartrate of potash is mixed with an excess
of chloride of calcium, which throws down all the
remaining acid as a lime salt, which is washed and
added to the former portion, and the whole is treated
with a sufficient quantity of dilute sulphuric acid to
form sulphate of lime, which is insoluble, and to set
free the tartaric acid. The filtered solution is evapo-
rated to the consistence of syrup, and set aside in a
warm place to crystallize. The crystals are often of
large size, the figure being that of an oblique rhombic
prism more or less modified; their density is about
1'7 : they acquire electric polarity by heat, similar to
tourmalin: they are colourless, transparent, iuodor-
ous, permanent in the air, very soluble in water, and
dissolving also in alcohol. The taste is sharply acid;
the aqueous solution gradually becomes mouldy by
keeping. It is largely employed by the calico printer,
for the purpose of evolving chlorine from bleaching
powder in the production of white or discharged
patterns on a coloured ground. [See CALICO PRINT-
ING.] Tartaric acid is much used as a cheap substi-
tute for citric acid in lemonade and effervescent
solutions: the crystals contain 03H4010+2HO.
Tartrate of potash, 2K0, 03H4010, may be prepared
by neutralizing cream of tartar with chalk, or by
saturating it with carbonate of potash: the neutral
tartrate thus produced is very soluble, whence it is
also called solnhle tartar; it crystallizes in right
rhombic prisms, which are permanent in the ‘air ; the
taste is bitter and saline. The acid tartrate of potash,
or cream of tartar, K0,H0,C8H4010, or purified

argol, is generally formed when an excess of tartaric
acid is added with agitation to a moderately strong
solution of a potash salt: it forms small gritty
crystals, which dissolve somewhat freely in hot water,
but most of the salt separates as the solution cools.
This salt has an acid reaction and a sour taste.
Exposed to heat in a close vessel it is decomposed ;
inflammable gas is evolved, and there remains a mix-
ture of finely divided charcoal and pure carbonate of
potash; the latter may be separated by means of
water. There are two tartrates of soda; a neutral
salt, 2NaO, C8H4OIO,+4:HO ; and an acid salt, NaO,
HO, CsH4010—t-2HO. They both crystallize, and are
readily soluble in water. The common saline or
efiroescing draughts are made by the addition of
tartaric acid to bicarbonate of soda. By neutralizing
a hot solution of cream of tartar with carbonate of
soda, and evaporating to the consistence of a thin
syrup, large, transparent, prismatic crystals separate ;
they consist of tartrate of potash and soda; 1 they
contain KO,NaO,CsH4~C1o+10HO: this salt efilo-
resces slightly in the air, and dissolves in 1% parts
of cold water: it has a mild saline taste, and is pur-
gative. The neutral tartrate of’ ammonia 2NH40,
CSH4OIO-l-2H0, is a soluble and efflorescent salt.
The acid tartrate, NH4O,HO,C8H401°, resembles
cream of tartar. There is also a salt corresponding
to Rochelle salt, in which ammonia takes the place of
soda. The tartrates of lime, hary/ta, strontia, magnesia,
and the oxides of most of the metals proper, are
insoluble or nearly so in water. Tartrate of copper
dissolved in a solution of caustic soda is a good test
for grape-sugar. [See SUGAR, Sect. I.] In forming
tartrate of copper by mixing dilute solutions of
tartrate of soda and sulphate of copper, no precipitate
is at first produced; but on striking the glass so as
to make it vibrate the liquor soon becomes turbid,
and if lines be drawn on the glass the precipitate
forms upon them. Tartrate of potash and copper is
formed by boiling hydrated oxide of copper and tartar
in water; the solution is used as a water colour, and
on boiling it to dryness it forms the pigment known as
Brunswick green. Tartrate of lead forms a Very per-
fect pyrophorus [see LEAD], inflaming on being shaken
out into the air. Tartrate of antimony and potash, or
tartar emetic, is prepared by boiling oxide of antimony
in a solution of cream of tartar: the hot concentrated
solution deposits on cooling crystals of tartar emetic:
they dissolve in 15 parts of cold and 3 of boiling
water; the taste is metallic, acrid and very disagree
able. The crystals contain KO,SbCs,CsH4C1o+2HO.
A solution of tartaric acid freely dissolves the hydrated
peroxide of iron, forming a brown liquid with an acid
reaction: on being evaporated at a gentle heat it
forms a brown, transparent, glassy substance, very
soluble in water and not precipitated by alkalies. The
tartrate and ammonia-tartrate of iron are used in
medicine, and are less nauseous than most prepara-
tions of iron. The double tartrate of iron and potash

(I) Also called Rochelle salt, or, Sel de Seignette, from having
being first prepared at Rochelle by an apothecary named
Seignette._ ..
814!
TEA.
was formerly used in medicine in the form of balls,
under the name of Glohuli llfarliales, Tarlarus
Jffarlialis and Boules do Nauoi: they were wrapped
in a piece of muslin, and suspended in water to form
a chalybeate solution.
The action of heat on tartaric acid is remarkable.
At about i000 the acid fuses, loses water and passes
through three different modifications of larlralio,
lartrelio, and anhydrous tartaric acid. Their com-
position is as follows :—
Ordinary tartaric acid ....... ..C,,H,O10 + 2H0
Tartralie acic’l...................2C,,H,O1° + 3H0
Tartrelic acid.......... .......C,,H,,O10 + H0
Anhydrous tartaric acid .... ..C,,H,O1°
Tartralic and tartrelic acids are soluble in water, and
form salts with properties different from those of
ordinary tartaric acid. The anhydrous acid is an
insoluble white powder.
Pym-acids are formed by the destructive distilla-
tion of crystallized tartaric acid. A heavy acid liquid
passes over, exhaling a powerful odour of acetic acid;
it contains pyrotartaric acid.
A salt called raoemio or paralarlario acid has been
found associated with tartaric acid in the grapes culti-
vated in some parts of the Upper Rhine, and also in
the Vosges, in France. It is somewhat less soluble
than tartaric acid, and separates first from the solu-
tion thereof: its solution precipitates a neutral salt
of lime, which is not the case with tartaric acid: in
other respects the two acids are almost identical. It
is interesting as being the first instance of isomerism
in organic bodies.
TAWING. See LEATHER, Section VI.
TEA, the name given to a dried herb, the infusion
of which forms the most common beverage of the
British Isles. Although its introduction into Europe
is comparatively recent, it is stated that “tea (sah) is
mentioned as the usual beverage of the Chinese by
Soliman, an Arabian merchant, who wrote an account
of his travels in the East about 11.1). 850.”1 It
does not appear to be mentioned in any European
work previous to the entrance of the Jesuit mission-
aries into China and Japan, about the middle of the
sixteenth century. The earliest account is said to
be by one Botero, in 1590, who remarks that “the
Chinese have an herb out of which they press a deli-
cate juice, which serves them as drink instead of
wine.”2 Texeira, a Portuguese, about 1600, saw the
dried leaves of tea at Malacca, and Ol'earius found them
in use, in 1633, by the Persians, who obtained them
from China by means of the Usbeck Tartars. Ander-
son states that in Great Britain, in the year 1660, no
mention is made in the new book of rates, of tea,
coffee, or chocolate, although they are all mentioned
in an Act of Parliament of the same year, whereby
a duty of eightpence is charged on every gallon of
chocolate, sherbet, and tea, made for sale. Pepys
refers in his Diary, 25th September, 1661, to “tea,
a Chinese drink,” of which he had never drunk
before. The Dutch East India Company are sup-

(li Macpherson’s History of European Commerce with India.
(2) Anderson, History of Commerce.

posed to have first introduced tea into Europe; and
for some years it was brought in small quantities
only. In 1664, the East India Company purchased
2 lbs. 2 oz. of tea as apresent for the king; and in
1678, they imported 4,713 lbs. of tea, by which time
it had begun to form an article in their trade.
Tea must have been used from very early times in
China. It has different names in different parts of
that extensive country—such as loha or oha, and lha,
whence are derived lsia, the, and lea.
The tea-shrub belongs to the family of the Camel-
lias, and closely resembles them. Though limited in
its culture to certain regions of Asia, it is still very
extensively ~cultivated within those regions, and gives
employment to a vast number of persons. In China,
whence the great supply is obtained, and also in
Japan, and in certain parts of India, labour is cheap,
and the cultivation and sale of tea can be carried 011
with a degree of success, which could not probably
be obtained in any other part of the world, however
favourable the climate to the health of the crop. Two
varieties of the plant, known to botanists as Thea
hohea, and Thea oiridis, supply the demands of the
commercial world. Thea uiridis abounds in the
northern districts of China, where it is cultivated
on the fertile slopes of hills, and never in the low
lands, and where the whole district appears covered
with shrubberies of evergreens, the plantations being
made not only in farms specially appointed for the
purpose, but in the garden of every peasant. The soil
for this crop must be rich, or the shrubs (which are
subject to a severe
trial in the frequent
gathering of their
leaves) will soon lan-
guish and die.
Two representations
of a tea leaf are given I
in Fig. 2130. They f'yi'll
will enable any one to ;y'
detect the spurious leaves with which tea ‘
is often adulterated.
The plant in culti-
vation in the southern
parts of China, and
especially about Can-
ton, is the Thea hohea, and it was long supposed that
from this variety black teas alone could be obtained,
while from Thea uiridis the entire supply of green
teas was manufactured. These ideas, however, are
entirely mistaken, for the latest and closest investi-
gations prove that the Chinese prepare black or
green teas at pleasure from either variety, and that,
if necessary, they can make both sorts from the
same plant. That they rarely make the two kinds
of tea in one district, appears to be merely a
matter of convenience. Throughout Che-kiang, and
what are known as the green tea districts of the
north, the plants are of Thea oiridis, and black tea is
not prepared; in the province of Fokien, and around
the Bohea hills, black tea alone is prepared; but,


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Fig. 2130.
TEA.
815
strangely enough, the plants are still of Time vz'ra'dz's,
and not T/zen bolted, although the latter variety derives
its name from the mountains of that province. We
have this on the authority of Mr. Fortune, a dili—
gent collector of facts concerning the tea districts.
Thus, there are green tree plantations on the black
tea hills, and from those plants the manufacture of
black tea was actively going on at the time of Mr.
Fortune’s visit.1 His investigations seem to prove
that the black and green teas, manufactured in tlie
northern districts of China, whence the foreign market
is chiefly supplied, are all obtained from Then nirz'dz's;
and that the black and green teas manufactured in
theneighbourhood of Canton are all obtained from
T/zea dO/léfé.
Reverting to the northern districts, we find that
the first tea-gatherings are in April, and consist of
delicate young leaf-buds, which it is very injurious
to the trees to remove, but which are considered a
choice and valuable gift among friends, and are sent
about in small quantities in that way. The showers
of spring enable the trees to recover from this early
loss of leaves, and in two or three weeks they have
brought out a fresh supply. The second gathering,
which takes place early in May, is the most important
of the season. A third and last gathering supplies only
inferior teas. At the time of the May gathering
every hill-side is covered in fine weather with groups
of persons, gathering the tea-leaves into baskets
made of split bamboo. The leaves are stripped off
rapidly without any special care, and the young seed
vessels go with them, and are dried into a form
resembling capers, as we sometimes find them in our
tea. When a sufficient quantity of leaves are gathered,
they are conveyed to acottage or barn, where they are
not allowed to'lie together if designed for green-tea,
but are immediately prepared for drying.
The great object in drying is to dispel moisture
without losing the aromatic and other properties of
the leaf, and by curling up the leaf to enable it the
better to retain those properties. The simple means
of doing this is as follows :—A number of round,



shallow iron pans, Fig. 2131, are built into brick-work
and chunam, which encloses a flue, passing along
beneath the pans, and having its fireplace at one
end, (as shown in the right-hand figure,) and its
chimney at the other, or at least a hole to allow the
escape of smoke. When the pans are fixed, the

( 1) Three Years’ Wanderings in the N orthem Provinces of
China, 860., by Robert Fortune, Botanical Collector to the H orti-
cultural Society of London. 8vo. London, 1847.
Two Visits to the Tea Countries of China and the British Tea
Plantations in the Himalaya, by the same, now in the service of
the Hon. East India Company in China. 8V0. London, 1853.

brick-work and chunam are carried up a little higher
round them, and particularly at the back, widening
gradually. When the fire is applied, the upper part
of the basins, which is of chunam, gets heated as well
as the iron pan, though in a less degree. The drying-
pans being low in front, the persons whose duty it is
to superintend the drying, can conveniently shake
and turn the leaves as they are thrown from the basket
into the pan, and keep them in constant motion
afterwards. In five minutes the leaves have given
out much of their moisture and have become soft and
pliable. They are then thrown upon a table made
of split bamboo, Fig. 2132, and therefore presenting
ridges, over which the leaves are rolled by the hands,
as in kneading
and rolling
dough, until a
further quan-
tity of mois-
ture has been '—
pressed out,
and a twisting
of the leaves
effected, which‘
causes them to occupy much less space than before.
Five minutes are spent in this way, and the leayges
are then shaken out thinly on a sort of screen,
made of split bamboo, and exposed to the actibn
of the air. Dry and cloudy days are the best for
this purpose: in sunny weather the moisture evapo-
rates too rapidly, and the leaves are left crisp and
coarse, whereas the desired condition is softness and
pliability. A considerable portion of moisture being
now got rid of, the leaves are again thrown into
the drying-pans, and the second heating commences.
Again a slow and steady fire is kept up, and persons
stationed at the drying-pans stir and throw up
the leaves so that they may be equally dried without
getting scorched or burned. The heat of the leanes
is now too great to allow of their being handled;
they are therefore stirred up with a bamboo brush,
and scattered over the smooth chunam-work, down
which they roll, and become more and more twisted
and curled. This operation is continued for about
an hour, when the drying of the tea is completed, and
it only remains to pick, sift, and sort the tea into
different qualities and prepare it for packing. Tea
dried in this manner is of a greenish colour, and
excellent quality. It is called Tsaon-z‘sz'ng, or the tea
which is dried in the pan, in contradistinction to
Bong-tsing, or that which is dried in baskets over
a slow fire of charcoal. The processes are just the
same as in the former ease up to the period of rolling
and exposure to the air; but instead of being put in
the drying-pans for the second heating, the Hong
tsing is shaken out into fiat baskets, which are placed
over tubs containing charcoal and ashes, emitting
avery gentle heat, which dries the tea less than by
the former method, does not impart so bright a green,
and is also aslower process. This tea is not designed
for exportation.
The mode of preparing black tea differs in a marked


816
TE A;
degree from that just described. The freshly gathered ‘
leaves are not taken at once to be dried, but are
allowed to lie for several hours, perhaps a whole
night, spread out upon bamboo mats. They are
then tossed about in the hands of the workmen, and
thrown into heaps. These are allowed to remain for
an hour longer, when they change colour slightly, and
become soft and moist. They are then roasted in the
pans for five minutes, and rolled on the bamboo table
as in the case of- green tea. After this they are ex-
posed to the air for three or four hours on bamboo
frames in front of the cottages, the workmen turning
the leaves, and separating them from each other.
They are then put a second time into the roasting-
pan for three or four minutes, and taken out and
rolled as before. They are now placed an inch thick
on sieves, resting in bamboo baskets, over a charcoal
fire. 'In five minutes they are removed for rolling
afresh, and then again set over the fire. This heating
and rolling may even be repeated a fourth time, the
leaves becoming darker and darker in colour. The
heat of the fire is now greatly reduced, by covering it
up, and the tea’ is placed thickly in baskets, and set
over it until it is completely dry, the workman making
an opening with his hand through the centre of the
leaves, to allow of the escape of smoke or vapour, and
then covering over the whole with a flat basket. The
tea is still watched, and occasionally stirred by the
workman until it is time to remove it from the fire.
The tea is now of its required black colour, a fact
easily to be accounted for by the slow processes de-
scribed, and by- the partial fermentation to which it
must be subjected while lying in heaps in the fresh
state. The colour and'active properties of the plant
are best preserved by the rapid drying, which pro-
duces greentea; hence the greater effect of green
tea on the nervous system, and which need not neces-
sarily arise from the. means used to heighten the colour
by the Chinese.
The fact of the artificial colouring of the teas of
commerce is undisputed, and Mr. Fortune tells us
that the process may be seen any day during the
season, by those who will give themselves the trouble
to' seek after it; and that the substances used to pro-
duce the bloom on green teas are Prussian blue and
gypsum. These are used in such small quantities as
not to be likely to produce any very injurious effect;
still they are objectionable adulterants, and are never
used by the Chinese to dye the teas for their own
consumption. This process of dyeing is sometimes
fraudulently carried on to pass off damaged and infe-
rior teas. Sir John Davis was witness to a transac-
tion of this kind which he thus describes_:1-—“ Large
quantities of black tea, which had been damaged in
consequence of the floods of the previous autumn,
were drying in. baskets with sieve bottoms, placed
over pans of charcoal. The. dried leaves were then
transferred in portions of a few pounds each to a
great-number of cast—iron pans, imbedded in chunam,
01". mortar, Over furnaces. At each pan stood a work‘fiti
man stirring the tea rapidly round with his hand,
having previously added a small quantity of turmeric
in powder, which of course gave the leaves a yellowish
or orange tinge, butthey were still to be made green.
For this purpose some lumps of a fine blue were pro-
duced, together with a white substance in powder,
which, from the names given to them by the work-
men, as well as their appearance, were known at
once to be Prussian blue and gypsum. These were
triturated finely together with a small pestle, in such
proportion as reduced the dark colour of the blue to
a light shade, and a quantity equal to a small tea-
spoonful of the powder being added to the yellowish
leaves, these were stirred as before over the fire, until
the tea had taken the fine bloom colour of hyson, with
very much the same scent. To prevent all possibility
of error regarding the substances employed, samples
of them, together with specimens of the leaves in each
stage of the process, were carried away from the place.
The tea was then handed in small quantities, on broad
shallow baskets, to a number of women and children,
who carefully picked out the stalks and‘ coarse or un-
curled leaves; and when'this had been done, it was
passed in succession through sieves of different de-
grees of fineness. The first sifting produced what
was sold as Hgsou-s/eiu, and the last bore the name of
Young Hgson. As the party did not see the interme-
diate step between the picking and sifting, there is
reason to believe that the size of the leaves was first
reduced by chopping or cutting with shears. If the
tea has not highly deleterious qualities, it can only be
in consequence of the colouring matter existing in a
small proportion to the leaf; and the Chinese seemed
quite conscious of the real character of the occupation
in which they were‘ engaged; for, on attempting to
enter several other places where the same process
was going on, the doors were speedily closed upon
the party. Indeed, had it not been for the influence
of the Hongist who conducted them, there would
have been little chance of their seeing as much as
they did.”
In some communications made to the Chemical
Society, Mr. Warrington confirms the above state-
ment as to the nature of the colouring matters
employed. These are usually-calcined fibrous gyp-
sum, turmeric-root, and Prussian blue; the latter,
judging from the specimen sent by Mr. Fortune to
the Great Exhibition, “being of a bright pale tint,
most likely from admixture with alumina or porcelain
clay.” Indigo also appears to be occasionally used as
a colouring matter. Other writers affirm, in opposition
to Sir John Davis, that the colouring is not intended
as an adulteration, “ but is given to suit the capricious
taste of the foreign buyers, who judge of an article
used as a drink by the eye instead of the palate.” It
is affirmed, that the natural yellow colour of green tea
would render it unsaleable among the London and
American dealers.2 Mr. B. Seeman, the naturalist of
H. M. S. Heralcl, while at Canton collected specimens
of teas, and inspected the process. He refers in his

(1) “ The Chinese,” by SirJ'ohnFrancis Davis, 1840.

(2)‘ Mr. J.-R..Reeves, as quoted by lyILWarrington. .
T FTA.
817
Journal, since published in “Hooker’s Journal of
Botany, and Kew Garden Miscellany,” for January
1852, to the “strange mistake made by Davis, of
supposing the Whole proceeding of colouring to be an
adulteration; and leaves his readers to infer that it is
only occasionally done in order to meet the emergency
of the demand; while it is now very well known that
all the green tea of Canton has assumed that colour
by artificial dyeing.” One of the great merchants
conducted Mr. Seeman over his own and another
establishment where the processes of manufacturing
the different sorts of tea were going on; everything
was conducted openly, without any attempt at con—
cealment. One example is given :——“.A. quantity of
Bo/zea Sans/rung was thrown into a spherical iron pan,
kept hot by means of a fire beneath; these leaves were
constantly stirred about until they became thoroughly
heated, when the dyes above-mentioned were added,
viz. to about 20 lbs. of tea one spoonful of gypsum,
one of turmeric, and two, or even three, of Prussian
blue. The leaves instantly changed into a bluish
green, and having been stirred for a few minutes they
were taken out.” In spite of all this apparent can-
dour, there appears to have been much falsification in
the manufacture, even as witnessed by so intelligent
an observer as Mr. Seeman; “for, on submitting these
materials to the action of chemical tests, there could
be no doubt that they consisted of indigo of a very
inferior quality, and leaving a very large proportion
of inorganic matter by calcination, and of porcelain
clay. It is also curious that the very case selected by
Mr. Seeman to illustrate the processes, is the conver-
sion, by means of this facing or glaze, of a low quality
of black tea (Bonea Sans/rung), valued at about 4.03. to
6d. the pound, into high quality green teas, valued at
from ls. to ls. 6d. the pound; but although Mr. See—
man does not allow this to be an adulteration, yet
surely he cannot deny that it is a fraud.”1
We are sorry to add that the falsification of teas is
carried on in Great Britain as well as in China—by
Christians as well as by Pagans. Mr. Warrington has
examined some imported black teas, to which the ap-
pearance of green teas was communicated. “ The
material used as the bodies for this process of manu-
facture, is a tea called scented caper ,- it is a small
closely-rolled black tea, about the size of small gun-
powder, and when coloured is vended under this latter
denomination; the difference in price between the
scented caper and this fictitious gunpowder being
about ls. a pound—a margin sufficient to induce the
fraud. This manufacture has, I understand, been car-
ried on at Manchester, and it was kept as secret as
possible; and it was only after considerable trouble
that some of my friends succeeded in obtaining two dif-
ferent specimens for me that could be fully depended on
as originating in the manufactory. It appears, that it
is generally mixed with other tea, so as to deceive the
parties testing it. How this manufacture was con-
ducted I am not prepared to say; but some prepara-
tion of copper must have been employed, as the

(1) Quarterly Journal of the Chemical Society, July 1852.
VOL. II.

presence of that metal is readily detected in the spe-
cimens I received. I believe, however, that this
sophistication has ceased.” Another and more flagrant
adulteration is also described by the same excellent
chemist. Two samples of tea, a black and a green, were
given him by a merchant for examination. The black
tea was styled scentecZ caper ; the green, gunpowder ;
and they are said to be imported into England in small
chests called catty packages. The teas are apparently
closely rolled and very heavy, and they have a fragrant
odour. The black tea is in compact granules, like shot,
of varying size, and of a fine glossy lustre of a very
black hue. The green is also granular and compact,
and has a bright pale bluish aspect, with a shade of
green, and so highly glazed and faced that the facing
rises in clouds of dust when it is agitated or poured
from one vessel to another; it even coats the vessel
or paper on which it may be poured. The facing was
found to be very tenacious, and required soaking in
water before it could be removed. In the case of the
green tea it consisted of a pale Prussian blue, tur-
meric, and a very large proportion of sulphate of lime.
The facing from the sample of black tea was perfectly
black in colour, and consisted of earthy graphite or
black lead. During the soaking of these teas they
showed no tendency to unroll or expand. One of the
samples was treated with hot water without any por-
tion of a leaf being apparent. It increased in size
slightly, was disintegrated, and it was found that a
large quantity of sand and dirt had subsided, which,
on being separated, was found to amount to 15
per cent.; but, as many of the lighter particles had
been lost in the washing, a weighed quantity of the
sample was carefully calcined until the whole of the car-
bonaceous matter had been burnt off, and the result was
equal to 37 '5 per cent. During this operation, also, no
expansion or uncurling of the leaf, as is generally to be
observed when heat is applied to a genuine tea, was
seen; in fact, it was quite evident there was no leaf
to uncurl, the whole of the tea being in form of dust,
held together by means of gum. The green tea was
similar to the black; it yielded 4555 grains of ash, &c.
from 10 grains of the specimen, or 45'5 per cent. A
specimen of Java gunpowder yielded 5 per cent. of
ash, so that there was in this sample 405 per cent.
of dirt and sand over and above the weight of ash
yielded by the incineration of a genuine tea. These
samples consisted of a mixture of tea-dust with dirt
and sand, agglutinated into a mass with a_gummy
matter, most probably manufactured from rice-flour,
then formed into granules of the desired size, and
lastly dried and coloured. Another imitation of un-
glazccl tea yielded 34. per cent. of ash, sand, and dirt.
Mr.Warrington states that “about '75 0,000 lbs. weight
of these teas have been imported into this country
within the last 18 months, their introduction being
quite of modern origin; and I understand that at-
tempts have been made to get them passed through
the Customs as manufactured goods, and not as teas,—
a title which they certainly merit, although it must be
evident that the revenue would be defrauded, inas-
much as the consumer would have to buy them as
Be
818
~TEA.
teas from the dealer. It is to be feared, however,
that a market for them is found elsewhere. The
Chinese, it appears, will not sell them except as teas,
and have the candour to specify them as he teas ; and
if they are mixed with other teas of a low quality, the
Chinese merchant gives a certificate stating the propor-
tion of the lie zfea present with the genuine leaf. This
manufacture and mixing is evidently practised to meet
the price of the English merchant. In the case of the
above samples the black is called by the Chinese Zz'e
flower caper ; the green, lie gunpowder ; the average
value is from 8d. to ls. per lb. The brokers have
adopted the curious term gum and dust, as applied to
these lie teas or their mixtures.”
Mr. Warrington gives the following results of the
careful incineration of a variety of teas; they are
valuable as affording an easy method of distinguish-
ing genuine from spurious teas, and in what propor-
tion the one is mixed with the other :—-
In 100 parts grains of ash.
Java Gunpowder Tea 5'0
Gun powder during the East India Company's Charter 6'5
Kemaon Hyson .. 5'0
Assam Hyson..................... . 6'0
Lie Gunpowder, No. l 45'5
Scented Caper 5'5
Lie flower Caper 37‘5
Mixtures containing these lie teas, No. l 22'5
Ditto ditto No. 2 110
We now resume our notice of genuine teas. Black
teas include Bo/zea, Congou, Scare/tong, and Pe/foe.
Bohea is with us the name applied to two kinds of
inferior teas ; in China it applies to the district where
various kinds of black tea are prepared. Congou is
a corruption of Koovzg-foo, “labour.” It is the next
higher kind to bohea, but has latterly given place to
some of the better kinds of bohea, which are much
stronger. Souchong, or Sedan-chomp, signifies “small,”
or “scarce sort,” and is the finest of the stronger
black teas. Pekoe is mainly composed of young
spring-buds, which do not hear much drying; conse-
quently this tea, though fine flavoured, does not keep
so well as some other teas, and it is also scarce and
dear. Hyson~pekoe, made from green tea~buds, is
never brought to England, but is kept for presents
in China, as already stated.
Green teas include Twmz/tey, Hyson-s/ez'n, Hyson,
Gwzpowder, and Yozmg fig/son. Twankey is the lowest
in quality, and the leaves are less twisted and rolled
than usual, but it is largely imported, and mixed by
retailers with the finer descriptions. It is said that
three-fourths of our importation of green tea consists
of Twankey. Hyson-skin is so named, because skate
in Chinese means refuse, and this tea is the refuse
portion of the fine tea called Hyson. The latter name
is a corruption of a Chinese word, signifying “ flourish-
ing spring,” from the season when the leaves are
gathered. Gunpowder is a more carefully picked
hyson, in which the best rolled and roundest leaves
are selected, and give a granular appearance, suggest-
ing the name. The Chinese give it a name which
means pearl-tea. Young Hyson is properly Yu-tsien,
“before the rains,” because gathered in the early
spring. The quantity is so small, that fraud is some-

times employed to imitate the genuine article. Other
green teas have been cut up, sifted, and passed off as
Young Hyson, so that the fame of this tea has de-
clined. All these varieties of tea are more fully
described in Davis’s work already quoted, and from
whence we have gained the above definitions.
Some years since it was discovered that the tea-
plant is indigenous in our Indian territories of Upper
Assam, being found there through an extent of country
of one month’s march from Suddya and Beesa, to the
Chinese frontier province of Yunnam. The cultiva-
tion of the plant is now carried on in these districts
to a very great extent. The capabilities of the valley
of the Dhoon are also great. This valley is several
hundred miles distant from Assam, and it is expected
that all the intervening parts of the Himalayas will
be found favourable to the crop. A most favourable
account of the tea plantations in the Kumaon and
Gurhwal districts of these mountains, was presented
to the Directors so long ago as 1847. At that time
17 6 acres were under cultivation, containing not fewer
than 322,57’ 9 plants. The crop was thriving in dif-
ferent places over It degrees of latitude, and 3 degrees
of longitude, and 100,000 acres were then available,
and might be readily adapted to the purposes of tea
cultivation. Thus there is reason to believe that the
period is not very far distant when the produce of
the north-west territories of India will compete suc-
cessfully with that of China in the markets of this
kingdom.1
The tea~plant is multiplied by seed like the English
hawthorn, and in consequence there are many slight
varieties among the seedlings, and in certain districts
where the climate and soil are favourable, a plant of
superior quality is obtained from the same kind of
seed which in other quarters may have produced a
less favourable result. Hence the importance of pro-
curing young plants and seeds from the best districts,
when it is desired to extend the cultivation of this
crop. Mr. Fortune was successful in obtaining, during
the summer of 1850, a large supply of tea seeds and
young plants from some of the most celebrated dis-
tricts of China, for transmission to India; the latter
were carefully planted in Ward’s glazed cases; and
these, with the collection of seed, reached Calcutta,
and finally their destination in the Himalaya tea-
plantations, in safety. These plantations, which are
in a very thriving condition, can now boast of having
a good number of plants from the best districts of
the green-tea country and of the black-tea country of
China. The tea-seeds had been on a former occasion
packed in loose canvas bags, or mixed with dry earth,
and put in boxes, or sent in small packages, by post ;
but none of these plans was successful, owing to the
short-lived nature of the seed. At length Mr. Ecr-
tune happily thought of sowing the seeds in Ward’s
cases, and watering them. They germinated during

(1) See also a valuable Report on the Government Tea Plan—
tations in Kumaon and Gurwahl. By William Jameson, Esq.
Superintendent of the Botanical Gardens, North-West Provinces,
India. Journal of the Agricultural and Horticultural Society of
India, vol. vi. Calcutta. 1848.
MT ETA.
819*
the voyage, and when they reached their journey’s
end, were sprouting up as thickly as possible. Mr.
Fortune recommends this plan with all other short-
lived seeds, and says, “Many attempts are yearly
made by persons in Europe to send out seeds of our
oaks and chestnuts to distant parts of the world, and
these attempts generally end in disappointment. Let
them sow the seeds in Ward’s cases, and they are
almost sure of success. If they are to be sent to a
great distance, they should be sowed thinly, not in
masses.” About 143000 young tea plants were added
to the Himalaya collection by this simple means, and
as the same diligent collector also obtained the ser-
vices of experienced tea manufacturers, and shipped
them with their implements to India, he may cer-
tainly be said to have done good service in the cause,
and to have enhanced the prospects of the trade in
India.
The chemical examination of tea has led to much
important information respecting this interesting
plant. Tea loses about 4 per cent. of water on being
dried at 212°, and there appears to be a further
loss of water on raising the drying heat to 230°.
In addition to the substance of the cells and vessels
of the leaves, which in black tea amounts to 27 or 28
per cent., and in green tea to 17 or 18 per cent., tea
yields from 41''? 6 to 5'56 per cent. of ash, which con-
sists of sulphuric acid, phosphoric acid, hydrochloric
acid, lime, potash, oxide of iron, and silica. Tea also
contains a number of vegetable substances, soluble in
different liquids, and common to all vegetables, such
as gum, wax, resin, chlorophyl, &c., in addition to
which, as partly peculiar to tea, are a volatile oil, taniiic
acid, and theine.
The following is an analysis, by Mulder, of Chinese
and Javanese tea :—
Cnmnsn. JAVAN ESE.
f_—A_‘\
Hyson. Congou. Hyson. Congou.
Volatile 0'79 0'60 0'98 0'65
Chlorophyl..................... 2'22 1'84 3'24 1'28
Wax 0.28 000 0'32 0'00
Resin 2'22 3 64 1'64 2'44
Gum 8 56 7'28 12'20 11'08
Tannine 12'88 17'56 14'80
Theine.......................... 0'43 0'46 0'60 0'65
Extractive (by means of‘
water and hydrochloric 46'40 40'48 42'04 38'52
Albumine ................... .. 3'00 2'80 3'64 1'28
Lignine 28'32 18'20 27'00
98'78 98'30 100'42 97 70
Saltsincludedinthe above 5'56 5'24.- 4'76 5'36
The tamzz'c acid is similar to that which occurs in
oak bark, [see Lnxrnmg] and in gall-nuts, [see
GALL-NUT.] According to the above analysis the
proportion is much greater in green than in black
tea. The volatile oil is of a citron yellow colour; it
floats on water and readily becomes solid, and by
exposure to airis quickly resinified. It tastes power—
fully of tea, and when placed on the tongue its in-
fluence extends to the throat, and it exerts apowerfnl
action on the nervous system. When tea is distilled
with water, this oil separates with it, and the infusion
of tea is also impregnated with it. The Maine con-

sists of 08H10N402; it neutralizes acids, and is thus
allied to the organic bases. It is separated from tea
by the following process by Stenhouse :——A decoction
of tea is treated with a slight excess of acetate of
lead, which throws down the tannine and most of the
colouring matters; the decoction is then filtered while
hot, and the clear liquor evaporated to dryness. It
forms a dark yellowish mass, which is to be well
mixed with sand, and sublimed at a moderate heat for
10 or 12 hours. The theine sublimes in beautifully
white anhydrous crystals, which are deposited upon
the paper diaphragm, which runs across the apparatus.1
The more slowly the operation is conducted the finer
are the crystals. Theine may also be obtained from
cofiee; the berries are not to be roasted, but only
slightly dried, and then ground or pounded, and re-
peatedly boiled with water until they are exhausted.
The filtered decoction should be precipitated while
hot by basic acetate of lead; filtered again and boiled
with hydrated oxide of lead, which produces a furthcr
precipitate, which is separated by filtration. The
clear liquor is evaporated to dryness and sublimed, as
in the case of the tea extract. A pound of coffee
thus yields about 15 grains of theine, not so white as
that from tea, but rendered so by a second sublima-
tion. From green Hyson tea 1'05 per cent. of theine
was obtained; from black Congou 102 per cent. ;
from black Assam 1'27, and from green Tonkay 098
According to Peligot, the proportion of theine in tea
is much larger; he obtained from Hyson 2'56 to 3&0
per cent., and from Gunpowder tea 2'20 to 4'10 per
cent. When theine is crystallized from water it com-
bines with 2 equivalents, and as a hydrate forms
beautiful white, silky needles. At 212° they lose
their water of crystallization; they fuse at 353°, and
are volatilized without change at 725°, so that theine
is not volatilized by the heat employed in drying tea.
Theine is readily soluble in hot water, much less so in
cold: it is precipitated by tannic acid, the precipitate
being insoluble in cold water, but soluble in hot.
Theine has no smell, but a bitter .taste. According
to Peligot, another nitrogenous substance, cascz'ne,
is contained in tea, but is only dissolved in water
when potash is present. He states that 100 parts
of‘ Souchong afford——





(1) Mohr’s sublirning apparatus, Fig. 2133, consists of a shallow
cast-iron pan, with a flat bottom and vertical sidgs, 8 inches in
diameter, and 2 inches deep. This contains
the substance to be sublimed. A sheet of
filtering paper is then stretched over the top,
and secured by paste to the sides of the vessel.
Over this is fitted a. paper cap made of thick F1, 2133
packing paper, joined together with paste, and y’ '
standing about as high as a man’s hat; it is secured by means of
string. The apparatus thus prepared is placed on a sheet of iron,
with a layer of sand intervening, over a slow fire. A modifies‘
tion of this apparatus is shown in Fig. 2134.
A funnel-shaped cover of sheet-iron is placed
over the top of the pot, and fastened on with
linseed-meal lute. This cover has a cylindrical
top, about 3 inches in diameter, which fits into
a square box of pasteboard or wood. A piece
Fig. 2134.
of fine muslin is strained over the mouth of the cylinder, and the
box may be provided with a sliding cover at the top for removing
the sublimed product. For further particulars see Mohr and
, Redwood’s Practical Pharmacy, 8V0. Lond. 1849.
3G2
820
TEA.
“TatGIIIIOIOOIUIOCIIUIIIIOIIQOIOO 8 .
Extract 43 containing {érfile'igg Exhausted leaves ....... .. 49 containing Caseine 140
100
If this statement be correct, then the most nutritive
portion of tea is thrown away in the leaves. Indeed
it is evident, from the analysis of tea, that many sub-
stances not soluble in water are rejected in the waste
leaves. Mulder obtained from 6 specimens of black
tea, as the portion extracted by hot water, from 29 to
38 per cent.; and from green tea from 341 to 416 per
cent. Peligot obtained from black tea 38 per cent,
and from green tea 48 per cent.; and eStimatedMthe
amount of nitrogen in this soluble portion, solely due
to theine, at 4% per cent. In 100 parts of tea 6 per
cent. of theine should be given out in the infusion,
but as tea is usually made in domestic economy about
one-third of this remains in the leaves. The ordinary
infusion often contains the volatile oil, theine com-
bined with tannic acid, gum, and some other extractive
matters. If the tea were boiled all the volatile oil
would be dissipated; and if the water is not suffi-
ciently hot, little or no theine would be extracted.
Hence the practice of making tea in close vessels with
boiling water is justified by chemistry: the water
must be actually boiling, both for “wetting the tea”
and for “ filling up the tea-pot,” and the tea-pot itself
ought to be of such a material as not to suffer loss of
heat by radiation: a bright silver tea-pot is the best,
and a-black earthenware tea-pot is the worst, that can
be used. A strong infusion of tea becomes turbid on
cooling, and is covered by a skin which is due to the
separation of tauuate of t/ieiue.
Some of the nomadic races of Middle Asia consume
tea both as an infusion and as a solid vegetable. They
are supplied by the Chinese with what is called brie/c-
tea, formed of the old and coarse kinds of tea-leaves,
the refuse and stalks of the better kinds, and the
leaves of other shrubs, all incorporated with the serum
of ox or sheep’s blood, and formed into thick ‘it-sided
cakes or bricks. “ It supplies these nomadic races
with a very portable food, which renders the very
worst water of the Steppes drinkable. They are in the
habit of rubbing it up with water, and boiling it with
the addition of some flour and 'suet of beef, mutton,
or horse (or in case of need a tallow candle) into a
kind of broth, which they take with the salt of the
Steppes, and, if possible, with ashes or other alkaline
salts. The latter are obviously used, though unwit-
tingly, to dissolve the caseine as much as possible.”1
The rapid extension of tea and cofi'ee among all
classes of society in Great Britain, and of coffee on
the continent, is a remarkable fact, and can only be
accounted for by referring to that wonderful instinct
which often takes the place of reason and science,
and acts with more effect and precision than either.
Much has beenwritten on the folly of poor people
spending money upon tea instead of nutritive food;
and yet, if Liebig’s view be correct, the folly belongs

_ (1) Knapp’s Chemical Technology, vol. iii. English transla-
tion. _

to the writers in question, and not to the purchasers
of tea; for, to say nothing of the diminution of in-
flammatory diseases consequent on its general use, tea
proves to the poor a substitute for animal food, and
to females, and persons confined by sedentary pursuits,
it becomes a substitute for bodily exercise. Liebig
says, “ We shall never, certainly, be able to discover
how men were led to the use of the hot infusion of the
leaves of a certain shrub (tea), or of a decoction of
certain roasted seeds (coffee). Some cause there must
be which would explain how the practice has become
a necessary of life to whole nations. But it is still
more remarkable, that the beneficial effects of both
plants on the health must be ascribed to one and the
same substance, the presence of which in two vege-
tables belonging to different natural families, and the
produce of different quarters of the globe, could
hardly have presented itself to the boldest imagina-
tion. Yet recent researches have shown, in such a
manner as to exclude all doubt, that caffeine and
theine are in all respects identical. it it it it Without
entering minutely into the medical action of caffeine
or theine, it will surely appear a most striking fact,
even if we were to deny its influence on the process of
secretion, that this substance, with the addition of
oxygen and the elements of water, can yield taurine,
the nitrogenized compound peculiar to bile :—~—
1 atom of cafi‘eine or theine = C,N,H,O,
9 atoms of water = H90,
9 atoms of oxygen = 0,,
caNaHleoao =
2 atoms of taurine 2 (C,NH.,O,O)
To see how the action of caffeine, asparagine, theo-
bromine, &c. may be explained, we must call to mind
that the chief constituent of the bile contains only 38
percent. of nitrogen, of which only the half or 19 per
cent. belongs to the taurine. Bile contains, in its
natural state, water and solid matter in the proportion
of 90 parts by weight of the former, to 10 of the
latter. If we suppose these 10 parts by weight of
solid matter to be choleic-acid, with 387 per cent.
of nitrogen, then 100 parts of fresh bile will contain
0171 parts of nitrogen in the shape of taurine. Now
this quantity is contained in 0'6 parts of caffeine;
or 2T86-ths grains of caffeine can give to an ounce of
bile the nitrogen it contains in the form of taurine.
If an infusion of tea contain no more than the 316th of
a grain of caffeine, still, if it contribute in point of
fact to the formation of bile, the action of even such
a quantity cannot be looked upon as a nullity. Nei-
ther can it be denied that in the case of an excess of
non-azotized food, and a deficiency of motion, which
is required to cause the change of matter of the tis-
sues, and thus to yield the nitrogenized product which
enters into the composition of the bile; that in such
a condition the health may be benefited by the use of
compounds which are capable of supplying the place
of the nitrogenized product produced in the healthy
state of the body, and essential to the production of
an important element of respiration. In a chemical
sense—and it is this alone which the preceding re-
marks are intended to show—caffeine or theine, aspa-
TELEGRAPH.
821
ragine, and theohromine are, in virtue of their com-
position, better adapted to this purpose than all other
nitrogenized vegetable principles. The action of these
substances in ordinary circumstances is not obvious,
but it unquestionably exists. Tea and coffee were
originally met with among nations whose diet is chiefly
vegetable.” '
The greater part of South America is supplied with
tea from Paraguay, known as Paraguay-tea. It is
a similar product to the tea of China, and is obtained
from a kind of holly, Ilerc Paraguarz'ensz's. It is of a
dirty-yellowish colour, a mixture of very small pieces
of leaf, with stalks, and part of the stems dried over
the fire. Its taste is peculiar, somewhat similar to the
inferior kinds of Chinese tea: it is taken as an infu-
sion with sugar, or with lemon—juice. There are seve—
ral varieties of this tea, some of which are said to
produce an unpleasant kind of excitement.
In the year 1850, the quantity of tea imported into
the United Kingdom, was 50,512,384 lbs. ; in 1851,
71,466,421 lbs.; and in 1852, 66,361,020 lbs. In
1850, the quantity retained for home consumption
was 51,172,302 lbs, on which the duty paid amounted
to 5,596,961L; in 1851, the quantity retained was
53,940,059 lbs. ; and in 1852, 54,724,615 lbs.
The amount of duty on tea has for some years
past been charged at the rate of 2s. 2%ct. per lb.
By an act passed in the Session of Parliament, 1853,
the duty was reduced to ls. 10¢. per 1b., until the
5th April, 18542; after which, until 5th April, 1855,
it is to be 1s. 6d. per lb. ; 1s. 36!. from the last date
until 5th April, 1856; and from and after that date
the duty is to be ls. per lb.
TEAK. See Woons.
TEASEL. See WooL.
TEETH of WHEELS. See WHEELS.
TELEGRAPH, a machine or contrivance‘ for com-
municating intelligence to a distance, whence the
origin of the word from wine distant, and ypdqbm to
write. It has also been called semaphore, from o'fipta
a sign, and qbe'pco I bear. In its most extended sense
telegraphic communication includes the whole art
of making signals, whether by means of special ma-
chines, fiags, lanterns, rockets, blue lights, beacon
fires, &e., or by audible signals, such as are afforded
by guns, trumpets, gongs, drums, &c. Whatever be
the signal, the party making it, as well as the party
for whom it is intended, must have previously ar-
ranged a certain meaning or sets of meanings to the
signals, however made. In early ages the signals
were rude, and the intelligence intended to be con-
veyed by them was of a very simple character. It
is only in comparatively recent times that machines
have been arranged for communicating long messages
to a distance by means of the semaphore: but that
was exposed to the serious inconvenience of not being
available by night or in foggy weather. The last
contribution to this art is the ELEernIc Tnnnenarn,
which is available by night as well as by day, and for
precision and rapidity in making the signals, as well
as in conveying them, is incomparably superior to all
other means for writing at a distance. Our article on

that subject will convey to the general reader a suffi-
cient knowledge of the details by which such sur-
prising results are accomplished.
The use of beacon fires is very ancient, and is men-
tioned in Jeremiah vi. 1. It is an obvious mode of
conveying information, and is said to be practised by
the Bosjesmans, a race of beings very low in intelli-
gence; so also, the Indians of America adopt another
very natural method of conveying information from
hill to hill, by throwing out their arms with or with-
out staves in them ; spreading out their cloaks, hold-
ing up skins, &c. While there is abundant evidence to
prove that such natural means of telegraphing have
been in use from the earliest times, arising in fact
from the necessities of man’s nature, it is only in com-
paratively recent times that special machines have been
contrived for the purpose. Kircher, Shottus, Kessler,
and the Marquis of Worcester, have suggested cer-
tain ideas for telegraphic machines, which however do
not appear to have been carried into execution, at
least in the times of their proposers. The Marquis of
Worcester, in his “ Century of Inventions,” published
about 1663, proposes the enigma, “ How at a window,
as far as the eye can discover black from white, a man
may hold discourse with his correspondent without
noise made or notice taken.” Also “ A way to do it by
night as well as by day, though as dark as pitch is
blac .” Bishop Wilkins, also, in a work entitled
“Mercury, or the Secret and Swift Messenger,” after
adapting to the English language a proposal for a
telegraph by Polybius, gives a plan for conveying
messages by night by means of torches; and he also
suggests, that in. arranging lines of telegraphic com-
munication, the telescope (or as he terms it, in honour
of its then recent discoverer “Galileus his perspec-
tive”), may be used for making out distant signals.
In the Philosophical Transactions for 1684:, Dr.
Hooke described a telegraph consisting of signals to
be repeated from station to station between the two
extremes of the space to be traversed. This plan,
which, like the previous proposals, was not put in
practice during the author’s life-time, has since been
repeated and varied many times. It consisted in
exposing in succession as many different shaped
figures or signs as there are letters in the alphabet,
If used by day, they were to consist of squares,
circles, triangles, 850. made of wood; if by night, of
torches or other lights disposed in a certain order.
These figures or lights were to be brought forth from
behind a screen 5, Fig. 2135, on rods, and exposed to
view. The first signal, being made at ' "
the terminus, would be simply copied
or repeated by the man at the first
station as seen by him through a
telescope directed to the terminus: Fig. 2135.
having repeated the signal, he would look through
another telescope directed to the second station, and
when he saw that the signal was correctly repeated
there, he would return to the telescope which looked
towards the terminus and repeat the second signal,
which, in like manner, would be taken up and repeated
at all the intermediate stations, until at length, at


7/ 1'


822
TELEGRAPH.
the other terminus all the signals being put together,
and representing letters of the alphabet, or numerals,
would have an intelligent meaning to persons who
had the key; for, of course, it is not to be supposed
that the men employed in making and repeating the
signals have any more knowledge of their meaning
than a postman has of the contents of theletters which
he delivers from door to door.
About 20 years after the publication of Hooke’s
machine, a similar contrivance was produced in France
by M. Amontons, in the form of a proposal, or model,
at least. The plan was published over Europe, and
excited much attention; but there is no evidence of
a working telegraph having been erected until 1793
or 17 94, when, in a Report by Citizen Barrere to the
Convention, Chappe’s telegraph, sometimes called the
T telegraph, from its position when at rest, is recom-
mended. It consists of a beam of wood moveable on
a pivot at the top of a post, as in Fig. 2136 : at each
extremity of this beam is a moveable
arm ; by which arrangement the beam
may be moved to any angle with
respect to the vertical post, and the
——- arms into any position with respect
Fie- 2136- to the beam. In this way as many
as 256 signals may be obtained; but as the message
was conveyed letter by letter, M. Chappe simplified
the working of the instrument by making use of an
alphabet of 16 letters only. These, of course, had
quite an arbitrary signification, which could be
changed at any time. for the purpose of secresy or of
rendering worthless any former key which might have
got into unfriendly hands. A line of such telegraphs
was formed, with one terminus at the Louvre in Paris
and the other at Lisle, the intervening stations being
situated on elevated spots. In this way the Commit-
tee of Public Welfare in Paris could communicate
with the army in the Low Countries; and Barrere
states that the news of the recapture of Lisle reached
Paris an hour after the troops of the republic had
entered that place. A signal could be repeated from
one station to another in 4 seconds, but 16 seconds
were allowed for observing the signal and noting it
down. It is stated, however, that it was difficult for
common men to report the signals correctly.
In 1794, Mr. Lovell Edgeworth invented his Tel“
Zogmp/z,1 Fig. 2137,
consisting of 4 wedges
or cones, moveable on
4 vertical posts, the
" * ~ - different positions of
F59- 2137-. , which were arranged
so as to represent letters or numbers» In the posi-


(1) Mr. Edgeworth claimed to have invented‘ in 1767 a plan for
distant communication‘ by employing a common windmill, and
arranging the various positions of its arms and sails, so as to re-
present certain signals. Mr. Edgeworth remarks, on the etymo-
logy of’ the word, that “while telegraph is a proper name for a
machine which describes at a distance, telelograpk, or, contractedly,
tellogmph, is a proper name for a machine which describes words
at a distance.”—Essag on the Art of Conveying Secret and Swift
Intelligence, published in the Transactions of the Royal Irish
Academy, vol. vi. - _

tion shown in Fig. 2137, the 4 wedges represent the
number 6103.
In 17 95 the advantages of the French T telegraph
were much talked of in this country, and many plans
were proposed for obtaining similar
advantages in Great Britain. The
Rev. J. Gamble, Chaplain to the
Duke of York, invented a Shatter
Telegraph, Fig. 2138, consisting of
5 boards placed one above the other,
and so arranged, that, by opening
one or more, as many signals could
be obtained as there are permuta-
tions in the number 5. The same
gentleman also invented a Radiaz‘eal
Telegraph, Fig. 2139, consisting of
5 wooden arms turning on the top
of a vertical post so as to form radii of a semicircle
at equal angles of 45°. By making any one or more
of these radii coincide with its neighbour, the number
and positions of the radii could be greatly varied.
In 17 95 the first Adnn'rallg Telegraph, Fig. 2140, on
the shutter principle, was re osed by . ,
Lord G. Murray. It vifasperected 2 over the Admiralty, and was first .\ i‘
worked on the 28th January, 1796. 'Q =
By means of a line of such telegraphs ‘
between London and Dover, a mes-
sage. could be conveyed from one ter- 3 Fig, 2'140,
minus to the other in 7 minutes. This telegraph was
used during the war, and continued in use until 1816,
when it was superseded by the semaphore, Fig. 2150.
When the boards are turned one quarter round so as to
present only their edges to the observer, no signal is
intended; but when 1 shutter or more is turned with
its broad surface to the next station, a signal is meant.
In this way 63 different signals or numbers can be
made out of the shutters, which are numbered in the
following order, 1 2 By presenting the broad
3 4
5 6
face of No.1 the signal 1 is intended, and this may
correspond with a particular letter in the key. No. 2
or No. 3 . . . No. 6 may, in like manner, have its own
meaning; then, by keeping No.1 standing, we may
open 2 . 3 . 4 . 5 . 6, and thus get the numbers 12 .
13 . 14 . 15 . 16. By keeping No.2 standing, the
numbers 23 . . . 26 are obtained, and by an extension
of the principle, all the numbers contained in the
following table are at length obtained :—


Fig. 2139.






1 23 123 234 1234 2345
2 24 124 235 1235 2346
3 25 125 236 1236 2356
4 26 126 245 1245 2456
5 34 134 246 1246 3456
6 35 135 256 1256 12345
12 36 136 345 1345 12346
13 45 145 346 1346 12456
14 46 146 356' 1356 13456
15 56 156 456 1456 23456
16 123456
These numbers or signals allow every letter of the
alphabet to be indicated, and there still remains a
TELEGRAPH.
823
number of signals with which words or questions in
common use may be connected.
In 17 941 or 1795, Mr. Garnet proposed to divide a
large circle, Fig. 21411, into ea parts, to represent the
,. letters of the alphabet, across which a move-
able radius or arm with a cross was to
traverse, and by placing corresponding divi—
sions by means of wires before the object
. glass of the telescope, the coincidence of
Fly’ 2141' the two radii or of the arm would point
out the letter intended to be repeated. It was found
that this plan was not practicable for long distances.
Fig. 2M2. The first French Semapherie Telegraph
said to have been erected on the palace of the
I _. 'j' x x
\ f \
u l


Fig. 2142.
Tuileries in 1796. It consisted of an immense
wooden frame with 7 arms; but it was soon aban-
doned, as all telegraphs must be which aim
at prodigious powers.
Fig. 2143. Mr. Edgeworth’s final plan
*- of the Tellograph, 1790.
F'g' 21”’ Fig. 214A. Idea of a Two-armed Tele-
T graph, having one arm in the form of a
cross, the other in the shape of a sword-
cutler’s sign, suggested to Mr. Edgeworth
Fie- 2144' in 1796.
Fig. 2145. The French Coast Telegraph, called the
Semaphore, said to have been invented in
1803.
, Fig. 2146. Captain (now Major General)
Pasley’s first Polggrammaz‘z'e Telegraph, in-
vented in 1804:, published in 1807.
rTTfi
Fig. 214s.


Fig. 2145.
Fig. 2147. Lieut. Col. Macdonald’s Shatter Tele-
graph, published in 1808. Fig. 2M8, is a shutter
telegraph proposed in India by Captain Swiney.







Fig. 2149. Captain Pasley’s
second .Polggramrrzatz'e Telegraph,
published in 1810.
Rear-Admiral Sir Home Popham’s




Fig. 2150.
Land Semaphore, adopted in 1816 by the Admiralty
instead of the shutter telegraph. This telegraph was
a. great improvement upon the preceding ones, in

simplicity of construction and in the mode of working
the arms. The vertical post is a hollow hexagonal
- mast, turning on a pivot at its foot, and
in a collar where it passes through the
roof of the cabin or telegraph observatory,
so that its arms may be made to work in
any plane. The arms are counterpoised by
q a mass of lead at the head of .-
each, so that they will remain in
any position into which they are
moved, and when out of use they fall into slots in the post, so l
as to be quite out of sight. The
arms are moved by means of two
winch handles situated in the
observatory near the base of the mast. These handles
give motion to two small spur wheels on vertical
axes, which gear into two similar wheels on horizontal
axes, and these act upon upright shafts or rods pass—
ing up the interior of the hollow post: at the upper
extremities of these rods, which are held in place by
bearings, are endless screws working into spur wheels
attached to the axes of the arms, by which means the
arms may be set in motion. In order to guide the
signal-man in making or repeating a signal, similar
toothed wheels and indices moving over graduated
arcs are attached near the bottom of the vertical rods,
so that whatever signal is made on the lower index is
faithfully repeated by the arm above.
Fig. 2151, represents Sir Home Popham’s
Semaphore, also established in ,-.~
1816.
Major-General Pasley has 'be-
stowed much attention on the
construction and working of tele-
graphs. He states1 that although he had long re-
garded Popham’s arrangements with satisfaction, he
was led to the conclusion that the use of two sepa-
rate pivots in the land semaphore and of two posts
in the ship semaphore was an unnecessary complica-
tion ; and that considering simplicity in construction
to be of more importance than the power of mak-
ing many changes, he had abandoned the polygram-
matic principle, and adopted what he terms the
Universal Telegraph for day and night signals. For
day signals this consists of an upright post, Fig. 2152,


Fig. 2149. Fig. 2150.
Ship


Fig. 215].
with two movable arms 4
{7 fixed near the top by a a.‘ f
pivot, and a mark called _‘\:1:;
the indicator on one side 2":1'5-3"
Fee-2152- of it. Each arm can ex-
hibit the 7 positions 1 . . . . . 7,
Fig. 2153, besides its quiescent posi-
tion called the stop, in which it
points vertically downwards and is
concealed by the post. In Fig. 2153,
the sign 17 is shown, the other positions of the arms
being indicated by dotted lines. The indicator serves
to distinguish the low numbers 1, 2, and 3, from the
(1) “ Description of the Universal Telegraph for Day and Night
Signals.” By C.‘W. Pasley. Lieut-Col. Royal Engineers, and F.B..S.
London, 1823.


8241
TELEGRAPH.
high numbers 7, 6, and 5. This distinction is of im-
portance, for it was found that in the use of Sir Home
Popham’s ship semaphores ambiguity sometimes arose
from the signals being seen in reverse, in which case
one number or sign would be mistaken for another.
By the addition of the indicator it was always evident
at a glance on which side the numerals commenced,
whether the semaphore were seen on the windward or
the leeward side of the ship. The signals given by
this telegraph are enumerated in the following
table,—
1 7 17 34 47
2 12 23 35 56
3 13 24 36 57
4 14 25 37 67
5 15 26 45
6 16 27 46
Fig. 2154 represents the telegraph fitted up for night
signals. It is shown on a larger scale in Fig. 2155.
One lantern 0, called
the central lag/at, is
fixed to the same
. pivot on which the
arms move. Two
other lanterns are
attached to the ex-
tremities of the arms.
A fourth lantern L,
used as an indicator,
is fixed on the same horizontal level with the central
light, at a distance from it equal to twice the length
of one arm, and nearly in the same plane in which the
arms revolve. With these 2 fixed and 2 moveable
lights, 28 signs can be made. As the indicator is
merely a mark which when once seen requires no
further attention, and the central light by night and
the post by day being merely guides to the eye, the
signs of this telegraph are really composed of the
combinations of only two moveable lights by night,
which renders this telegraph very simple. The arm
and the indicator for the day signals are of wood
framed and panelled: in hot climates plates of copper
may be used for the panels. The indicator plays in
a mortise cut in the upper part of the post, and is let
down into its horizontal and raised into its vertical
position by a rope and pulley. The arms are fixed
externally one on each side of the post, and exactly
counterpoised by means of light frames of open iron-
work which are not seen by day at a short distance.
This counterpoising is necessary to allow the arms
to remain in any given position without being held by
the hand or stopped by some mechanical contrivance.
Motion is given to the arms by means of an endless
chain passing round and acting upon a couple of
pulleys, one of which is fixed to the arm itself and
turns upon the same pivot ; the other moves upon a
pivot fixed to the lower part of the post. The chain
consists alternately of single and double plates, of an
oblong form, and riveted together at the ends on the
principle of a watch chain. The pulleys are furnished
with projecting teeth or studs, which engage the
double or open parts of the chain. In this way each
arm follows accurately the movements of an index or


Fig. 2154. '
\ \
/

lever below, attached to the lower pulley, which has a
dial plate opposite to it marked on the post for the
guidance of the signal man. On board ship a rope is
sometimes used instead of the chain. At the end of
each arm two light pieces of iron meet in an angle of
45°, forming an open triangle, to the vertex of which
the moveable lantern L is attached by means of a pin.
A cylindrical counterweight W is also fixed to the
end of the iron counterpoise. The lanterns and weights
are fixed at dusk and removed by daylight, so that at
permanent stations the roof of the signal-house over
which the telegraph stands has a small flat terrace
accessible by a ladder or staircase. In the interme-
diate stations two lanterns are required for the centre
light, one on each side of the post, as in Fig. 2155, in
which 0 c are the central lanterns, LL the moveable
ones, and ww the counterpoise weights. The indi-
cator light may be fixed to a separate post as in Fig.
2154!, or be attached to a rod r strengthened by a

n ‘ 1‘
_ - "m... ...........\... ., .“nm
- _._=-===’2 _ ' '
wmu-muyymz \ . n Itlm ’.
1. ~".—. - ...~ - <.- .<- -
i ‘II "III! I
~ r
i
l
— 1 ' _.-——.~ ._r—. -_::

Fig. 2155.
brace 12, and guy ropes g g, as in Fig. 2155. For
ships or for field service the length of the telegraphic
arm does not exceed 5 01' 6 feet; but at permanent
stations on shore they may be much longer. Lieut-
Col. Pasley’s calculation is that they should be about
1 foot per mile of the distance between any 2 stations,
in order to be distinguished by a common portable
telescope of moderate power. This length is com—
puted from the centre of motion to the end of the
arm. The width of the arm need not exceed %% ths of
its length, and not less than 7‘,- th or {5th. The indi-
cator for the day signals should be of the same width,
but only gths of the arm in length. The arms should
be painted black, and placed so as to be seen without
any background; but if a background be unavoidable,
the arms should be painted so as to contrast with it;
and should the background vary greatly at different
periods of the day the arms should be painted in bold
black and white chequers. The lamps used on shore
are square like those used in mail-coaches, having the
two glass sides opposite to each other, so as to show
the light in 2 directions only: but for sea service the
globe-lamp is best; the light‘shines in all directions
through a strong globular glass, in which are fitted a
copper top and bottom pierced with air-holes.
Much discussion was formerly held respecting the
TELEGRAPH.
825
comparative merits of shutters and arms. Colonel
Macdonald, who has published a very voluminous
work on “ Telegraphic Communication,” 1 writes
strongly in favour of the shutter principle, and asserts
that “ the semaphore arm of proper dimensions is not
to be seen in clear weather so well as the common
sized boards, and in cloudy weather by no means so
well,” and that “for this climate the boarded telegraph
is in all respects more advantageous.” To this state—
ment Mr. Gamble replies as follows :—“ It is a
theorem in optics that the apparent magnitude of an
object varies nearly in the inverse ratio of its distance.
Hence it follows that the larger its dimensions, to
the greater distance will it be visible. But the nature
of our atmosphere, even in its most transparent state,
is such as to render any calculation grounded on this
principle extremely erroneous; and in general its
density so obstructs, and its refracting powers cause
such confusion in the rays issuing from those surfaces
which are not placed sufiiciently distant to be distinct,
that their image falling upon the retina is frequently
so ill defined as to render it difiicult to determine
either their figure or position; for which reasons,
that which I shall term insulation is generally a quality
more requisite to give distinctness to an object, than
magnitude of superficial dimensions. An example of
this distinetness arising from insulation cannot be
more readily obtained than by taking a page of printed
paper and fixing the eye on some particular letter, as
I ; then retiring from it, the letter will be so confused
with the surrounding ones as not to be easily distin-
guished. But if the same letter I be printed on a
plain sheet of paper, standing by itself, or insulated, the
eye will then not only discern it at a much greater
distance, but the image falling single and unen-
cumbered upon the retina, we shall be able to deter-
mine whether it be inclined to the right or to the
left, or whether it be placed horizontally on the paper.”
Experience has abundantly proved that the arms of
the semaphore were seen with much greater distinct-
ness than the shutters of the telegraph. Indeed, in
order to test the comparative merits of the two, when
the shutter telegraph was superseded by the semaphore,
the former was left standing for awhole winter on the
same hill at Nunhead with the new semaphore. The
result was that the semaphore was often visible when
the shutters were so much enveloped in fog or mist
as to render it impossible to distinguish which parti-
cular shutter was closed or opened. It also appears,
from a journal kept by the oflicer at the station, that
in the course of the winter the days on which the
semaphore was visible exceeded those on which the
shutters could be seen by fully one third.
The six-shutter telegraph is capable of producing a
larger number of combinations than the two-armed
semaphore, without using the stop-signal, or that
'WlllCll separates one word or one sentence from

(1) “ ATreatise explanatory of a new system of Naval, Military.
and Political Telegraphic Communication, 82c.” By John Mac-
donald, Esq. F.R.S. late Lieut.-Col. and Engineer. 8V0. London,
1817. The work is accompanied by a copious Telegraphic Dic-
t onary.

another. But the Admiralty semaphore had abundant
powers, as is proved by the following table :—

No. of No. of No. of
Signal Signifi- Signal Slgnifi- Signal Signifi-
by 1 and 2 cation. by l and 2 cation. by 1 and 2 canon.
arms. 8.11118. arms.
1 1 15 G 43 X
2 2 16 H 44 Y
3 3 21 I 45 Z
4 4 22 K 46
5 5 23 L 5 l
6 6 24 M 52
1 A 25 N 53
2 B 26 O 54
3 C 31 P 55
4 D 32 Qu 56
5 E 33 R 61
6 F 34 S 62
11 7 35 T 63
12 8 36 U 64
13 9 41 V 65
14 0 42 W 66


making in all 48 separate and distinct signals.
The reader who is curious in telegraphs will find a
large number, which we have not even mentioned by
name, described in C01. Macdonald’s work, and also in
many of the volumes of the “Transactions of the
Society of Arts,” especially vols. xxvi. xxxiv. xxxv.
and xxxvi.
In the navy, flags of various forms and colours have
been long used for conveying signals from ship to
ship. It is said that Lord Howe proposed to mark
the signal flags with numbers which should corre—
spond with words or sentences previously agreed on.
In 1798 the Admiralty issued a signal-book on this
plan: it contained about 400 sentences expressive of
the common operations of the fleet ; but if a message
had to be conveyed which was not found in the book,
the ship proposing to send the message had to signal
“for a boat,” or “a boat from each ship,” in order to
convey it. This defect was remedied by the proposal
of Sir Home Popham, to make the flag-signals repre-
sent the letters of the alphabet, as well as words and
sentences in comrexion with the numbers. His other
proposal, also adopted, was to cut the signal-flags “so
that the selvages of the buntin may be brought on
the outer edges of the flags and the gorings in the
centre; by which means the outer edge is susceptible
of the least air of wind, and when the flag blows out,
the gorings assist in keeping it out; whereas the old
flags had a hem on the outside which rendered them
difficult to move without a fresh breeze, especially in
damp and rainy weather, as the hem then became
heavy.” The number of flags, &c. required for making
signals in Sir Home Popham’s Code is 9 flags, 5
comettes, 5 triangles, and 5 pendants. Sir John
Barrow objects, that with such a number it is next to
impossible, in calm weather, to make out the figure
and colour of the flags; and equally so when expanded
by the wind if the situation of the observer be such
that only the edge is presented to the eye. He pre-
fers Popham’s sea-telegraph, Fig. 2151, or Pasley’s
Universal Telegraph, Fig. 2155.
The numerical system with flags, &c. is not difficult.
Nine differently coloured or variegated flags repre-
sent the numerals l . . . . . . . 9 ; there is also a sepa-
rate flag for 0, and another called a substitute, for
826
. TELEGRAPH.
repeating any flag, under which it is hoisted, should
the same figure occur twice in the number to be ex-
pressed: a pendant is also sometimes used as a sub-
stitute for the top figure. In this way, by the use of 11
different flags and a pendant, any number from 1 to
999 can be expressed without displaying more than 3
flags, or 2 flags and a pendant at one time.
The flags, &c. should be of the brightest colours,
and present the strongest contrasts. When ships are
at considerable distances apart, or in the morning or
evening, or on a dark day, it is not easy to distinguish
one full colour from another, all the colours approach-
ing black in appearance. At the distance of a very
few miles scarcely any full colours, except a scarlet
and a blue, can be distinguished. Red, blue, yellow,
and white can be seen at greater distances than any
others, and are therefore the colours used as signals.
But even these sometimes occasion difiiculties; the
yellow being confounded with a dirty white, and the
blue with red. In combining these colours to obtain
variety, stripes, spots, and chequcrs are used, the op-
position of the combined colours being as strong as
possible, and the stripes, &c. not less than 1-third the
breadth of the flag. Red should never be striped or
spotted with blue. See LIGHT.
Attempts have been made of late years to introduce
a uniform code of signals among merchant ships, by
which they may readily communicate at sea, or with
the coast stations. An Association for the purpose,
under the superintendence of Mr. B. L. Watson, was
established some years ago, and the Lords of the
Admiralty have ordered that Mr. Watson’s signal-
books shall be supplied to all the vessels of the Royal
Navy, in order that they may have the means of readily
signalling any merchant ship at sea that is in posses—
sion of this plan. The whole code consists of 13 flags,
by which any message can be conveyed from one ves-
sel to another, or between a vessel at sea and one of
the coast stations established by the Association on
prominent points about Great Britain. In connexion
with these coast stations there were lines of sema-
phores (now superseded by the more efficient electric-
telegraph) from the Downs to London, from Holyhead
to Liverpool, and from the Spurn to Hull; and from
such stations communications are transmitted to a
central office in London, and also to the owners or
consignees of vessels entered in the telegraph list;
for which privilege an annual subscription of 208. is
charged for each vessel. So also any message from
the owners of a vessel as to change of destination,
&c., can be communicated from any station within
sight of which the ship may pass.
The construction of a “Telegraphic Dictionary”
was at one time a favourite employment with persons
engaged either in inventing or making frequent use
of telegraphs; and as the inventors of knick-knacks
(and there is a good deal of knick-knackery in this
subject) are numerous, so are the books on the sub-
ject. One of these dictionaries extends to 140,000
numbers, with a separate sentence to each number.
Another occupies 120 pages, with 3 columns in a
page, and 60 sentences in each column: in a large

number of pages each sentence begins with the per-
sonal pronoun “He,” 20 pages with “ If,” and so on.
Spelling the sentences would be much more certain
as to the meaning, and in many cases more expedi—
tions. The communications should be in an abbre—
viated form, and in such cases spelling is to be pre-
ferred. Thus the sentence, “ Order the Agamemnon
out of harbour, and direct her to proceed to Spithead,”
will be sutficiently expressed by “Agmemn. to Spthed.”
It is also of importance to condense the point or im-
portant part of the communication into the former
part of the sentence, so that no serious mistake may
arise should foggy weather intercept the message.
For example, during the Peninsular War a telegraphic
message was sent from Plymouth to London: the
words “Wellington defeated-—-” were received, when
a fog prevented further communication, thus leaving
the government for some hours under the terrible
impression that our great general had sustained a
defeat. Whereas, had the message commenced with
the words “French defeated at” &c., the truth would
have been more concisely expressed, and the fog would
have bisected the message with less inconvenience
than when it was put in the form, “Wellington de—
feated the French at,” &c. Sir John Barrow, who
relates this anecdote in the Encyclopedia Britannica,
article NAVY, says, “ In clear weather, the rapidity of
working single signals, the short compass within
which any message may be condensed, the impossi—
bility of committing any mistake that cannot be imme-
diately rectified, more than compensate for the differ-
ence of a few minutes which the use of sentences may
probably save. In cloudy or foggy weather the latter
method will always be liable to mistake. If expe-
rience may be assumed as a guide, the practice of the
Admiralty of spelling all sentences for the last 30
years, must decide in favour of that system.”
Before the introduction of the electric telegraph
the semaphore was worked with remarkable facility
and despatch. A short message could be conveyed
between Portsmouth and the Admiralty in 1% minute,
but a special message, which was always sent at a
stated hour each day, and for which therefore all
parties were on the look out, has been sent through
in 31 seconds. The signal-men, during clear weather,
were always on the look out, and such was the facility
which they had acquired from long use in reading off
the signals, that even in hazy weather, when to an
unaccustomed eye the signal would be invisible or
too indistinct to be decyphered, the signal-man would
read it with facility. Foggy weather however greatly
interfered with the transit, so that at times the trans-
mission of signals along the entire line was imprac-
ticable for hours or even days together. In order to
avoid as far as possible any inconvenience from this
delay, there was a rule that if any station in the line,
through fog, inattention, or any other accident, should
be unable, within two minutes, to pass the signals it
had received onward to its next adjacent station, then
this last station in the perfect portion of line was to
receive the whole of the message, acknowledge its re-
ceipt by the return signal, and send on the signals
TELEGRAPH.
827
either by post, express, or semaphore, as might be
found advisable, to its final destination.
Signals are also made at sea by means of guns,
rockets, blue-lights, &c. Gun-signals are distinguished
by the time which is allowed to elapse between the
discharges; and thus the signals may be slow, motle—
rate, and gale/e. Half-minute guns are the slowest
among single signals. Quarter-minute guns admit of
two subdivisions. With well-trained gunners intervals
of 15 or 12 seconds may be taken for slow firing, 8
or 10 seconds for moderate, and A or 5 seconds for
quick firing. A small number of firings, varied in this
way as to time, will give a large number of signals.
Thus 5 guns with the variation of only gale/e and
moderate will give 20 signals. Here, as in flag signals,
the most simple must be appropriated to the most
important orders.
The signals used on railways require some notice in
this place, if it were only to extend the knowledge of
the important fact, that numbers of persons are in-
capable of distinguishing colours, or are, in fact,
atilicted with what is called eoloar-hlz'aclrzess. This
subject has been partially investigated at different
times, but it has lately been very fully inquired into
by Dr. George Wilson of Edinburgh, from whom we
have received the following communication :1—
“ The colours selected to distinguish the danger-
signals on our railways, and, if I mistake not, those of
other countries also, are red and green, which are used
by day on painted plates of metal and flags of linen
or cotton, and by night on glass illuminated from be-
hind by oil or gas-lights. In using the colours in
question, it is plainly taken for granted that the large
majority of mankind are strongly impressed by them,
and easily detect the difference between them ; and it
is believed that no inquiry is instituted by railway-
companies into the colour-vision of their servants. It
is certain, however, that at present the great mass of
the community of all ranks receive no education in the
discrimination of colours, and are not, at least in the
case of males, acquainted with the names of more than
a very few; whilst in the humbler classes an exami-
nation of more than 700 males has led to the conclu-
sion that they do not familiarly name more than seven
colours, namely, red, blue, yellow, green, brown, white,
and black; even such important names as orange and
purple being never employed, and no substitutes being
used for them.
“ Such an ignorance of names, although not neces—
sarily implying an ignorance of colours equally great,
yet points to an habitual indifference to the distinc-
tions between colours, on the part of the community
at large, which shows how cautiously these should be
had recourse to as a means of arresting the attention
of unpractised eyes.
“ But a far more important source of danger from
the employment of coloured signals, lies in the fact

(1) Those who desire to extend their knowledge on this
subject, cannot do better than study Dr. Wilson’s highly interest-
ing paper in the "Monthly Journal of Medical Science.” Edin-
burgh. The number for November, 1853, contains the first part
of this paper.

that a considerable number of persons are born with
an incurable defective perception of colour, and are
thereby incapacitated from distinguishing between
certain colours. Ooloar-hlz'aclaess, as this defective
perception is best named, occurs in males, (in whom
it is greatly more common than in females,) to an ex-
tent which is not generally suspected or credited.
Provost found 1 male in 20 more or less colour-blind,
Seebeck found 5 in 40. Professor Kelland found 3
extreme cases in 150 students, and I found 2 in 120,
of whom, however, only 80 were specially examined.
I have recently, with the assistance of two friends,
examined the troops in garrison at Edinburgh, and
among 737 men, including 6 officers, I found 53
colour-blind, or nearly 1 in 141. Of these, 11 con-
founded green with scarlet, 2 light-green with pink,
l6 dark-green with brown, 20 green with blue, 1 pink
with light-blue, 1 pink with yellow, and 2 yellow with
purple, but only to a slight extent. The men were
examined by daylight, and one by one: but the exa-
mination of so many persons singly, although spread
over ten days, was necessarily rapid, and several cases
were doubtless overlooked.
“ Setting aside the colours not used in railway-sig-
nals, and disregarding, as of minor importance, the con-
fusion of green with blue, it appears, that among 757
healthy there were 29, or 1 in 25, who confounded
green with scarlet, or pink, or'brown; of whom 11, or
1 in 67, could not distinguish a red from a green
danger-signal. Prof. Kelland’s 3 cases were equally
severe, so that 1 in 50, according to his statements,
could not be signal-men; and among my examined
students of last year there were 2 in 80. During the
last nine months I have become acquainted with nearly
50 persons who cannot distinguish red from green;
and altogether, the present state of our knowledge
warrants the conclusion that l in 50 of the male po-
pulation is liable to confound red with green; but I
shall immediately show that the proportion of the com-
munity who cannot be safely trusted with the present
coloured railway-signals is probably much larger.
~“ It is a remarkable fact, that the subjects of this
affection seldom occur singly in a family, and that
there are often six persons within two generations,
fathers, uncles, sons, nephews, cousins, as the case
may be, all more or less colour-blind. Among the
soldiers whom I examined, two of the cases, ofiicers,
are brothers, but I had no means of learning any-
thing concerning the relatives of the remaining cases.
It seems, however, important to draw attention to
the fact, that my numbers, or any others obtained in
a similar way, under-estimate the number of colour-
blind persons in the community, since many, perhaps
the majority of these, belong to a group of relations
similarly affected.
“ The following conclusions are founded on my own
observations, and on the voluntary confessions of
trustworthy colour-blind persons; but it is believed
that they are quite in harmony with the observations
of preceding writers on colour-blindness.
“ 1. The colours least liable to mistake by the
colour-blind are yellow and blue.
828
TELEGRAPH—TELLURIUM.
“ These when pure and full, and well illuminated,
are generally perfectly distinguished.
“ 2. The colours most liable to confusion by the
colour-blind are as follows.
“ Bright red, scarlet, and crimson, are confounded
with bright green, and occasionally with black; dark
red, russet, and brown, with olive and dark green;
purple in all its shades, crimson, lilac, lavender, and
violet, with blue. Pink, with pale yellow, with light
blue, and more rarely with light green. Blue with
green.
“ 3. In extreme cases the confusion of all those
colours occurs in a single person; in less severe cases
it is limited to two colours, but in the great majority
four colours are concerned.
“ 41. Red and green being the most important colours
in reference to Railway-signals, the following points
are of special importance in connexion with them :—
“ 1. Some of those who confound red and green with
each other, do so in full sunshine, both by transmitted
and reflected light, however near the coloured object
be to the eye.
“ 2. It is more common, however, to find that there
is a certain though not constant power of distinguish-
ing between the colours in question, but this power
diminishes with great rapidity when they are removed
to a distance from the eye, so that a separation of a
few feet or a few yards, according to the severity of
the cases, abolishes all sense of distinction between
red and green. Many of the colour-blind have first
become aware of their defect by discovering their in-
ability to distinguish red flowers and fruit from the
surrounding green leaves, unless when close to them.
It is needless, therefore, to urge that in testing the
qualifications of a railway servant to discern coloured
signals, his ability to distinguish between red and
green azear the eye is not a sufficient criterion of his
freedom from colour-blindness, which must further be
tried by removing the signals to as great a distance
from him, as they require to be seen from, on oc-
casions of danger.
“ 3. Those who confound bright red and green at a
distance from the eye, are almost invariably found to
confound dark red with dark green although close to
the eye; and as the coloured day~signals, especially
the flags, which alone are available in some of the
most pressing emergencies, soon tarnish and darken,
the effect of time is to change light reds and greens
into much darker shades, and thereby continually to
diminish the distance (small at the best,) at which the
two signals can be distinguished from each other by a
colour-blind observer. It is thus desirable on railways
to ascertain to what extent the darkening of colour-
signals renders them undistinguishable or obscure to
those who can discern them when new and bright.
“ 41. Many persons are found who mistake dark red
and brown for olive and dark green, who do not
appear on a cursory examination to mistake the
brighter shades of red and green; but all such
persons are to be regarded with suspicion, as present-
ing at least the lower degree of colour-blindness in
reference to red and green, and asdlikely to fail in

seeing the signals at present in use, at distances
where those with normal vision could easily discern
them. Now in the Edinburgh garrison there was
nearly one man in 40 who mistook dark green and
brown, in addition to those who mistook bright green
and red, so that the proportion of those in the com-
munity who are colour-blind to a degree that makes
it hazardous to employ them as signal-men, is pro-
bably double what it appears to be, when we reckon
as such only those who confound the brightest shades
of red and green.
“ 5. It is a remarkable fact, that many of those who
cannot distinguish red from green by day-light, can do
so by gas or candle—light; so that this general con-
clusion may be drawn, that as far as mere colour is
concerned, the present night signals are safer than the
day ones. But it must not be inferred from this that
they are safe, or that those who are colour-blind by
day see normally by night. They see the doubtful
colours better, but still badly.
“ 6. There is in many of those who confound red
with green, a positive insensibility of the retina to
red, so that in twilight they confound red with black.
Thus several distinguished foxhunters are known to
me, who cannot tell the black coats from the red in a
hunting field in twilight, or at a short distance in
day-light. Such persons would not merely confound
one signal with another, but frequently not see a red
one at all.
“ If then the present system of signals on railways
be retained, a most strict investigation of the servants
should be made; but it seems much safer to dispense
with colour by day-light except as an auxiliary, and
to trust to the shape and motion of large arms.
“The great difliculty is with the hand signals,
especially if 3 signals are to be shown, for no colour-
blind person can see three primary colours, and yellow
is liable to confusion with white when it is tarnished.
For a two-colour system, white and black would be
the best throughout the day ; and blue and white by
night. For pressing emergencies hand lamps are
much too small. I greatly approve of a suggestion
in the Times, that signal lights with red fire or green
fire should be in the possession of Guards, for such
occasions as those which led to the recent accident
near Dublin.
“It is vain to expect, as is urged in the Times,
that an engine driver who had been gazing at an
immense fire, should see a small red lamp.
“ But I cannot enter into a question so large and so
difficult as that of the best system of signals on
Railways.”
TELESCOPE. See LIGHT—LENS.
TELLURIUM, Tefié, a rare metal, or semi-metal,
(named from tellus, the earth,) found in a few. scarce
minerals associated with silver, lead, and bismuth,
apparently replacing sulphur. Tellurium has the
colour and lustre of silver, and by fusing and slow
cooling it exhibits rhombohedral crystals : it is brittle,
a comparatively bad conducter of heat and electricity:
, its density is 6'26, and it fuses at a little below red-
heat. It burns when heated in the air, and forms
TEMPLATE—TERRA COTTA—TESTS—THEODOLITE.
829
tellarous acid, TeOe. There is also tetturic acid, TeOs,
two chlorides, and a hydruret, resembling sulphuretted
hydrogen.
TEMPERATURE. See HEAT—TI-IERMoMETER.
TEMPERING. See STEEL—ANIvEALINe—SAw, &c.
TEMPLATE or TEMPLET, a pattern plate for the
formation by filing or otherwise of curved works.
They are useful in cases where the works are wanted
in great numbers and of exactly the same form, and
in various works that are required to be truly circu-
lar, but do not admit of being finished in the lathe.
Templates are often formed of hardened steel. They
are also much used for setting out and producing
series of holes in some kinds of work where exactness
is required.
TENACITY.
METAL, Fig. 1439.
TENON AND MORTISE. See GARPENTRY.
TENSION. See STRENGTH or MATERIALS —
ELAsTIeITY—METAL.
TERRA COTTA, or takes? clay, a term applied to
certain architectural decorations, figures, vases, &e.,
modelled or cast in a paste composed of a pure clay
and a fine grained colourless sand or calcined flints,
together with pulverized potsherds or crushed pottery.
The article is then slowly dried in the air, and fired
to the hardness of stone in a kiln. The clay should
resemble that used for making pipes, [see POTTERY
and PORCELAIN, Sect.1V.] and should contain little
or no iron. The true terra cotta of the ancients was
less baked and less durable than that of the moderns,
and was indeed little more than sun-baked clay of
considerable purity. Some of the architectural orna—
ments in terra cotta in the Great Exhibition attracted
considerable notice. Messrs. Willock & Co. of Man-
chester exhibited a complete model of a decorated
Gothic church in terra cotta, besides a Corinthian
capital, a chimney-piece painted in imitation of oak,
with the slab in stone, a flower-stand, a piece of Gothic
tracery, and other smaller articles, the cost being
stated to be from 50 to 75 per cent. below the price
of carved stone-work. Mr. Blanchard also exhibited
a portion of a Gothic pinnacle, a capital, the of good
colour and well-executed details. The material is
described as being a composition of the best white pipe-
clay, crushed pottery'ware, calcined flint, flour-glass,
and white sand, all well amalgamated and burnt at a
high temperature. [See STONE, ARTIFICIAL] The com-
position requires to be very homogeneous, on account
of the great shrinking of the articles in the drying
and firing.
The following passage occurs in the Jury Report,
Class XXVIII. “The Jury recognise the importance
of introducing a material so useful and so economical in
many cases, especially where the absence of durable
stone interferes with the construction of public build-
ings. A well made terra cotta may be regarded as
almost indestructible by ordinary exposure, and al-
though in colour it is generally inferior to good stone,
and the parts are liable to warp in burning, yet for
some kinds of ornament, and for many practical pur-
poses, the result is everything that is needed.”
See STRENGTH or MATERIALS—

TERRA DE SIENA, a brown fcrruginous ochre,
used in painting. See OcHRE.
TESTS are those substances in solution, or in the
gaseous form, which are used in chemistry to detect
the presence of other bodies also in solution; which
they do by forming insoluble precipitates, by changing
colour, or by certain other characteristics well known
to the practical chemist. Thus a few drops of a so-
lution of carbonate or acetate of barytes added to a
solution containing sulphuric acid produces a dense
insoluble precipitate of sulphate of barytes. Now, as
the carbonate or acetate of barytes does not produce
this effect with any other acid, the formation of such
a precipitate is a certain test of the presence of sul-
phuric acid. So also the presence of silver in solution
is made evident on the addition of muriatic acid, by
the formation of a white curdy precipitate of chloride
of silver : lead is detected by sulphuretted hydrogen ;
iron by solution of galls; the presence of a free acid
by litmus paper, which is reddened, and of a free
alkali by turmeric paper, which is turned to a reddish
brown ; or the litmus paper, reddened by an acid and
restored to its original blue colour, also indicates the
presence of an alkali. These, and a thousand similar
cases, which at first view rank only as individual facts,
requiring a separate memory for each, are so impor-
tant in their application and in the progress of che-
mistry, as to take rank with scientific principles of
great breadth and generality. Minute directions as
to Tests and Testing are given in Earaday’s “ Chemi-
cal Manipulation,” and also in Bowman’s “ Introduc-
tion to Practical Chemistry.”
TEXTILE FABRICS. See VVEAVING.
THEINE. See TEA.
THEODOLITE. This is the most important in-
strument used by surveyors for taking horizontal and
vertical angles, since by its construction it is not ne-
cessary in either case that the objects should be in
the same horizontal or vertical planes. The simplest
form of the theodolite is a divided circle, which is to
be set parallel with the horizon, and a telescope which
has so much motion in a vertical plane as to enable
the observer to view any required object above or
below the horizon. Although the instrument is of
comparatively recent date, the origin of its name is
not well known. Up to the latter half of the last
century, the quadrant was employed in all accurate
surveys, although Rtimer had previously shown the
superiority of the reflecting circle with three verniers.
Both instruments, however, as well as all reflecting
instruments, can only measure the angular distance
between two objects; that is, an angle, in whatever
plane, which happens to include them and the eye;
from which angle the horizontal one has to be found by
calculation. The first example of a survey conducted
with an entire circle is said to be that of Zealand, by
Bugge, in 1762-8. Borda afterwards invented the
repeating circle, for adding mechanically any number
of successive measures of the same angle, so that the
average of the whole might be more accurate than
any single observation could be. This still leaves the
reduction of the angular distance to a horizontal and
830
THEODOLITE.
a vqrtical angle to be made by computation. This
has continued the chief instrument in French sur-
veys; but Englishmen have a tendency to place more
confidence in mechanism, and to substitute it, where-
ever possible, for computation, although this neces—
sarily involves both more expense and more causes
of error. The theodolite makes this reduction me-
eizanz'eallg, which of course renders the observer
dependent on two or three more instrumental adjust‘-
menl‘s than those required by reflecting instruments;
and also on a firm fixture to the earth, while those,
however delicate, can be held in the hand, the measure
becoming, by Iladley’s admirable contrivance, indepen—
dent of any motion in the quadrant itself. Ramsden
completed his great theodolite in 17 87, the circle of
which is 3 feet in diameter. This was used for a
triangulation to connect the observatories of Green-
wich and Paris. The principal triangles of the
English, Irish, and Indian surveys have been ob-
served with this instrument, or with instruments
exactly similar.
The theodolite, as at present constructed, consists
chiefly of a pair of parallel plates, with adjusting
screws, fitting on a tripod, (similar in construction to
the supports to the Y and other levels [see LEVEL-
LINGJ) ; a horizontal limb for measuring horizontal
angles, and a vertieal_limb for measuring vertical
angles.
The two parallel plates, L and v, Fig. 2156, are cir-
cular, and fit accurately one on the other. The lower
plate has a projecting chamfered edge graduated to
half degrees: the upper or vernier plate has portions
of its edge chamfer-ed off, so as to form with the
chamfered edge of the lower plate continuous por-
tions of the same conical surface. The chamfered
part of the upper plate is graduated so as to form the
verniers by which the limb is subdivided into single
minutes. A 5~inch theodolite, such as that repre-
sented in Fig. 2156,1 has two such verniers, 180°
apart. Larger ones have 3 at distances of 120°, by
which, in their average reading, the error of centering
is entirely counteracted. The lower plate of the hori-
zontal limb is attached to a conical axis, which passes
through the upper parallel plates, and terminates in a
ball fitting in a socket on the lower plate. The axis
is hollowed for the reception of a similar conical axis
ground accurately to fit it, so that the axes of the two
cones may exactly coincide, the perfection of the instru-
ment for horizontal measurement depending greatly on
the axes of the two cones being identical. The upper
or vernier plate is attached to the internal axes, so that
while the whole limb can be moved through any de-
sired horizontal angle, the upper plate only can also
be moved through any desired angle, when the lower
plate is fixed by the clamping screw 0, which tightens
the collar D. r is a slow motion screw, which moves

(1) Our figure represents the theodolite as improved by Mr.
Castle, and engraved in his “Treatise on Land Surveying and
Levelling,” 2d ed. 1845. In our description we have chiefly
followed Mr. Heather’s excellent little “Treatise on Mathema-
tical Instruments,” published in W eale’s Rudimentary Series.
There is -a.masterly article on the “ Theodolite” in the Penny
Cyclopazdia. .

the whole limb through a small space, for the purpose
of adjusting it more perfectly after the collar D has
been tightened by the clamping screw 0. e is a
clamping screw for fixing the vernier plate to the
lower plate, and l is a tangent screw for imparting a
slow motion to the vernier plate upon the lower plate
when so clamped. There are two spirit levels B B
on the horizontal limb, at right angles to each other,
and a compass e in the centre between the supports
FF of the vertical limb. The vertical limb NN is
divided/on one side at every 30 minutes each way
from 00 to 90°, and subdivided by the vernier attached
to the compass-box to single minutes. On the other
side is marked the number of links which are to be
deducted from each chain, for various angles of incli-.
nation, so as to reduce those distances which are
measured along ground which rises and falls at such
angles to corresponding horizontal distances. The
axis A of the vertical limb must rest upon its supports
F n, in a position truly parallel to the horizontal limb,
and the plane of the limb NN should be truly per-
pendicular to its axis. The vertical limb N N carries
a bar with two Y’s, which support the telescope, and
below the telescope is a spirit-level s s, attached to it
at one end by a joint, and at the other by a capstan—
headed screw. The axis A can be fixed by a clamp-
ing-screw o, and the vertical limb can be then moved
through a small space by the slow motion screw 2'.
Previous to taking an observation, the telescope
must be adjusted for parallax and for collimation;
the horizontal limb must be adjusted to set the levels

Fig. 2156. 5-1ncrr THEODOLII‘E.
to indicate the verticality of the azimuthal axis ; and
the vertical limb must be adjusted to set the level
beneath the telescope to indicate the horizontali'ty of
THEODOLITEITHERMOMETER.
831
the line of collimation. The adjustments for parallax
and collimation are the same as those noticed under
LEVELLING for the Y level. The adjustment of the
horizontal limb is made by first setting the instrument
as accurately as possible by eye, by moving the legs
of the stand until the bubbles in BB are nearly cen-
tral, and the plummet which is suspended from a
hook under the body of the instrument hangs freely
above the centre of the station. One leg should he
moved, and each leg is capable of a double motion.
The collar 1) is then tightened by the clamping
screw 0; the vernier plate is unclamped, and turned
round until the telescope is over two of the parallel
plate-screws. The bubble h of the level 3 s is to be
brought beneath the telescope to the centre of its
run, by turning the tangent screw 2'. The vernier
plate is turned half round, and the telescope again
brought over the same pair of parallel plate-screws ;
if the bubble of the centre be not in the centre of its
run, it must be brought back to the centre, half way
by turning the parallel plate screws over which it is
placed, and half way by turning the tangent screw 2'.
The operation is to be repeated until the bubble re-
mains truly in the centre of its run in both positions
of the telescope, and the vernier plate being turned
round until the telescope is over the other pair of
parallel plate screws, the bubble is to be again
brought to the centre of its run by turning these
screws. The bubble will now retain its position while
the vernier plate is turned completely round, showing
that the interior azimuthal axis about which it turns
is truly vertical. The bubbles of the levels 13 13 being
brought to the centre of their tubes will therefore be
adjusted to show the verticality of the internal azi-
muthal axis. The vernier-plate having been clamped,the
collar 1) is to be loosened by turning back the screw 0,
and the whole instrument moved slowly round upon
the external azimuthal axis ; and if the bubble of s s
beneath the telescope maintain its position during a
whole revolution, the external azimuthal axis is truly
parallel with the internal, and both are vertical at the
same time; but if the bubble does not maintain its
position, it shows that the two parts of the axis have
not been accurately ground, and that the instrument
is imperfect.
In adjusting the vertical limb the bubble of the
level s s being in the centre of its run, the telescope
(with the level attached and already adjusted parallel
to its line of collimation) is to be reversed, end for
end, in the x’s, and if the bubble“ do not remain in the
same position, correction for 1-half the error is to
be made by the capstan-headed screw at one end,
and for the other half by the vertical tangent screw 2'.
The operation is to be repeated until a satisfactory
result is attained. On turning the telescope a little
to the right and to the left, if the bubble do not
remain in the centre of its run, the level s s must
be adjusted laterally by means of the screw at the
other end. This will probably disturb the first adjust-
ment, and the whole must then be carefully repeated.
By means of the small screw which fastens the
vernier of the vertical limb to the vernier-plate over

the compass box, the zero of this vernier may be set
to the zero of the limb, and the vertical limb will be
in perfect adjustment. In large theodolites a second
telescope is placed beneath the horizontal limb, for the
purpose of detecting any accidental derangement of
the instrument during an observation, by noting
whether it is directed to the same point of a distant
object at the end of an observation as it was at the
beginning. The vertical limb also, in the larger theo-
dolites, admits of an adjustment to make it more
accurately in a vertical plane when the horizontal
limb has been set in perfect adjustment. And also in
small theodolites, when the vertical limb is perma—
nently fixed to the horizontal, Mr. Heather remarks,
that an instrument which will not bear the following
test should be returned to the maker for better adjust-
ment. The azimuthal axis having been set truly
vertical, direct the telescope to some well-defined
angle of a building, and making the intersection of the
wires exactly coincide with this angle near the grormd,
elevate the telescope by giving motion to the vertical
limb, and if the adjustment be perfect, the intersec-
tion of the cross-wires will move accurately along the
angle of the building, continuing in coincidence with
it. A plumb line suspended from the cornice would
however be more trustworthy than the ver'ticality
of the angle itself.
In an extensive survey the principal points should
be determined by a system of triangles proceeding
from an accurately measured base of considerable
length. The angles of these triangles should be ob‘
served with a large and perfect theodolite, the correc-.
tions for the curvature of the earth, refraction, 850.
being applied. The boundaries of the space to be
surveyed being accurately determined, and a series of
stations laid down throughout, the spaces included
between these stations may be subdivided into spaces
of 3 or 4 miles, the boundaries of which may be sur-
veyed by a traverse, i. e. with a chain and a portable
theodolite, and the details of the country within these
spaces may be sketched by means of the prismatic
compass. See SURVEYING.
THERMOMETER. Having, in the article HEAT,
stated at some length the laws which regulate the
action of instruments constructed for the measure-
ment of temperature, and having also, under $TEAM
and STEAM-ENGINE, given a further exposition of
those most important laws, our attention will be
chiefly confined, in the present article, to a descrip-
tion of the modes of preparing thermometrical instru-
ments, the methods of using them, and the reliance
which is to be placed upon their indications.
Thermometrical instruments may be divided into
three classes :-—1st. Those which are intended merely
to compare the temperatures of bodies, and to which
the term thermometer is usually restricted. 2dly. Those
which are intended to compare the quantities of sen-
sible heat evolved by different actions or contained by
different bodies: such instruments have been usually
called ealorz'meters. 3dly. Those which are intended
to compare the effects of different radiations or heat-
ing rays. As their indications depend on the deference
832
THERMOMETER.
of temperature between their different parts, they
have been named dg'fereutiut thermometers.
The first thermometer was constructed about the
beginning of the 17th century. It consisted of a tube
' » t, Fig. 2157, open at one end, and a
glass bulb B at the ‘other: the air in
the bulb being first expanded by heat,
the open end of the tube was inserted
into the-coloured liquid in the cup 0.
As .the ‘bulb became cool, the enclosed
air contracted, and a portion of the
liquid ascended the tube, by atmol
splieric pressure on the surface of the
liquidinithe cup, until the liquid in
the t'ubelequalled the bulk of air ex-
pelled by the heat. Any process ‘tend-
Fio~2157- ing to heat‘the'bulb above the tem-
perature of the surrounding air‘ would cause the
enclosed air to expand ; thereby depressing the liquid
in the tube; but if the temperature‘ of the bulb
were lowered beyond that of the surrounding air, the
enclosed air would contract, and more liquid be forced
into the tube. It a scale of equal’parts were applied
to the tube, a rough idea would thus be afforded of
the differences in temperature of bodies affecting the
bulb. ' Instruments of this kind are called air-thermo-
meters ,- and‘formerly weat/zer glasses, since they served
to indicate'cold and warm weather.
This instrument was improved by Boyle, who ex-
changed the cup c for a bottle, Fig. 2158, into the
neck of which a tube-was cemented, so as to confine
a portion‘ of air in the bottle instead of in the bulb,
which was dispensed with, the tube being open at
both ends. The 'bottle could thus' be dipped ‘into
liquids, and their relative temperatures compared; but
i the open tube, and the evaporation or
contamination of the liquor contained
in it,_ were objections which prevented
this form, ‘and other attempts at im-
provement, from having. any value in
scientific ‘observations.
The Florentine Academicians saw
the necessity of removing the register-
ing fluid from the pressure of the air,
and also of obtaining a scale with fixed
potu‘ts, such as should be applicable to
all thermometers. Their instrument
Fig. 2158. _ depended on the expansion of spirits of
wine instead of ~ air, and the mode of construction
was as follows :-——A tube, with a bulb at one end and
open at the other, washeated, and when a portion of
the air wasexpelled, the open end was plunged into
spirits of ‘wine, which, as the bulb cooled, ascended
into‘ the stem :' the bulb was then held downwards
over a flame, ‘so as to boil the spirits and expel the
remaining-portion of- air. While the vapour’ was
issuing‘fromthe end of the tube the flame of a blow-
pipe was applied to it,'thus melting the glass and
sealing it hermetically?’ The application of a scale
was less happy than 'the structure of the-instrument.
The points ‘selected ‘for the ‘graduation'were, 1st, the
cold of ice and snow for the lower limit,‘and, 2dly,




the greatest summer-heat of Florence for the upper
limit. As these points are variable, they were of no
Value for the purpose intended.
On the introduction of this thermometer into
England, the first improvement of Boyle was to sub-
stitute coloured spirit for colourless. He proposed to
fix one point of the scale by observing the height of
the liquid ,in the stem when the bulb was placed in
thawing oil of aniseed; a temperature which he pre-
ferred to that of melting ice, because it could be pro-
cured at any time of the year; for this oil melts or
freezes at about 50°, and is therefore in this country
seen about as often in the solid state as in the liquid.
Hooke is thought to have suggested the temperature
of freezing water as one of the fixed points; Halley
proposed .the boiling point of spirits as another.
The differences of opinion respecting the standard
minimum of temperature arose from the supposition
that the freezingpoint of water was higher in one
country than in another.
As spirit boils at a comparatively low temperature,
the tubes filled with it were liable to burst on being
exposed to temperatures beyond their boiling points.
Newton proposed to remedy this defect by using oil
instead of spirit ;‘ but this was found to be very
sluggish in its motions within the tube, to adhere to
it strongly, and to vary in fluidity at different tempe—
ratures.
The present mode of rendering thermometers com-
parable with each other is commonly ascribed to
Newton, who was the first to take advantage of the
fact, that whenever a thermometer is placed in melting
snow or ice, the liquid always ‘stands at the same point
of the tube, and that the boiling point of water is
almost equally constant in all ordinary states of the
weather. Now, if we divide the space between these
two points into any arbitrary number of degrees, and
continue degrees of the same magnitude both upwards
and downwards, all thermometers thus made will in-
dicate the same degree when exposed to the same
temperature. Before this capital invention of New-
ton, the instrument could scarcely be said to be more
than a toy; but it now became almost an artificial
organ of sense; the observations made with it being
comparable, however widely they might be separated
by time or place. i l '
Another decided improvement was the adoption of
mercury enclosed in a bulb and tube purged of air.
Halley conceived the idea of employing mercury ;4 but
he rejected it on account of the small amount of its
expansibility, which he estimated at 717,- from freezing
to boiling water; but it has since been found to be
3%.3-5 that is, 55-;- measures at 32°, expand ‘into 56%
measures by being heated to 212°. Romer is said to
have first adopted this important i-mprovement'and
also to have constructed Fahrenheit’s scale. Fahren-
heit was an instrument maker, a native ‘of Dantzic,
residing at Amsterdam : his thermometers were known
over- Europe early in the eighteenth. century.
The advantages attending the use of mercury as
the thermometrie fluid are—71. It enlarges in bulk more
equably for equal increments of heat than most other
THERMOMETER.
833
liquids. 2. From its great density it is more easily
freed from air than either alcohol or oil; a quality of
much importance in the construction of these instru-
ments. 3. It has a very convenient range; for while
oil becomes viscid and very tenacious at low temper-
atures, and water1 and alcohol boil before they attain
a high temperature, mercury will retain its liquidity
unimpaired for a range of more than 700°. 4!. It accom-
modates itself more speedily to the temperature of sur-
rounding bodies than many other liquids. It was stated
under HE AT, that a less quantity of heat is required to
raise a given quantity of mercury to a certain temper-
ature, than is necessary to raise an equal quantity of
water to the same temperature; and this is in effect
the same as saying that mercury becomes heated and
cooled more speedily than water. This property is
due to the metallic nature of mercury; metals are the
best conductors of heat, and a fluid metal would con-
duct heat from one particle to another more rapidly
than water or any other liquid.
As liquids do not follow the same law of expansion,
that is, do not equally increase their expansibiliiy
with increase of temperature, it follows that two
thermometers made with different liquids, although
both he graduated in the manner above described so
as to coincide in their indications of two fixed points,
would nevertheless not coincide exactly when the
temperature was at any other point. Thus, as
mercury is more equable in its rate of expansion than
any other liquid, a thermometer of any other liquid,
although made to coincide with the mercurial one at
the boiling and freezing points of water, would yet
give a rather lower estimate of all temperatures be—
tween these two points, and a rather higher estimate
of all temperatures above boiling and below freezing.
Now in the comparison of scientific results at different
times and in different places, it is evidently necessary
to adopt some standard of universal reference; and
‘in the case of the thermometer pure mercury is the
standard. The methods of obtaining it pure are given
under MERCURY.
The glass capillary tubes which are prepared for
the construction of thermometers should be pre-
cisely equal in diameter throughout, if we would have
them measure equal increments of bulk. But in fact
the tubes as obtained from the glass-houses are
generally frusta of very elongated hollow cones, which
by extension become more or less perfectly cylindrical.
We may see how this happens by drawing out a
thread of sealing-wax, which will always be larger at
the ends than towards the middle. If one part of
the bore be larger than another, a division at that
part in a scale of equal parts would belong to a
greater change in the volume of the mercury than a
division at the other part, where the diameter is less.
In order to determine the value of one of these tubes
a drop of mercury may be drawn into it so as not to
occupy a space in the bore of more than % inch. The
mercury is to be gradually moved through the tube

(1) Water is also inapplicable as a thermometric fluid from the
unparalleled singularities of its changes of bulk at low tempera-
tures. See Hear.
VOL. II.

from one end to the other, and kept stationary at
different parts by holding the tube horizontally: the
space which it occupies in the tube at different
places is to be carefully measured; if this be the
same at every part, the bore is evidently uniform
throughout; but if the mercury occupy a less extent
at one part than at another, the bore must vary in
diameter, and hence cannot afford accurate results
when used as a thermometer tube. The application
of this test will enable the careful maker to select
such tubes or portions of tubes as most nearly ap-
proach to perfect accuracy of bore. Thermometer
tubes are sometimes made with an elliptical bore, to
allow a small column of mercury to be more visible
when expanded at right angles to the line of vision.
When the tube is selected a bulb is blown upon it
at one extremity by softening the end in the flame of
a table blow-pipe, and tying the other end to a bottle
of India-rubber containing dry air: on compressing
the bottle the air will expand the softened glass into
a bulb. Air from the mouth would be injurious in
this operation on account of the moisture which would
be introduced into the tube. The size of the bulb
must depend on the purposes to which the thermo-
meter is to be applied; but, of course, the larger the
bulb, in proportion to the stem, the more sensitive
will the thermometer be to changes of temperature,
for the greater will be the rise or fall produced by a
change of bulk bearing any given ratio to the whole
bulk of the liquid. But although there is no limit
to the size or length allowable in a thermometer used
only for indicating atmospheric temperature, it is
otherwise with an instrument intended for discover-
ing the temperatures of small bodies, for unless its
bulb be much smaller than the bodies to which it is
applied, it will sensibly alter their temperature, and
not acquire the exact temperature which they had
maintained in its absence.
As the pressure of the air acts more equally upon
a spherical than on a cylindrical or pyriform body,
the spherical is preferred; but when the bulb is very
large in proportion to the stem, one of the two latter
is adopted. with bulbs of large size containing mer—
cury, a slight pressure of the fingers, apart from their
natural heat, causes the mercury to ascend in the
stem: and with such bulbs the varying pressure of
the atmosphere has an influence on the capacity of
the bulb. It may seem strange that the atmospheric
pressure should have more effect in compressing the
bulb than the weight of the mercury in distending it;
but such is always the case in thermometers of ordi-
nary length.
The bulb is filled with mercury much in the same
way as the first thermometer, Fig. 2157, was filled with
liquid, viz. by applying heat to the bulb so as to
rarefy the air, and in allowing it to cool with the open
end under mercury, a portion thereof will enter the
stem and bulb. The tube should be placed in a nearly
horizontal position, with its open end below the sur-
face of the mercury. Heat is again applied to the
bulb, and the mercury in it is boiled: the vapour of
mercury expels the remaining air, and when the
3 H
83a
THERMONEETER.
flame is withdrawn the vapour will gradually be con-
densed into the liquid form, and the tube and bulb
will be entirely filled with mercury forced up into
them by atmospheric pressure. Another plan .for
completing the filling of the bulb and tube is to roll
a slip of clean writing-paper round the open end of
the stem, and tie it firmly, so that it may form a
cylindrical cup capable of holding as much mercuryr
as the bulb. A drop of mercury is placed in the paper
cup, but it descends no further on account of the
capillary bore of the tube, which will not allow the
mercury to enter by its own unassisted weight. On
applying a flame to the bulb the vapour of mercury
soon rushes up into the paper vessel through the
upper mass of mercury, and on removing the flame
the vapour of mercury left in the bulb and stem sud-
denly returns to the liquid form, leaving a vacuum
which is filled by the mercury in the paper cylinder
descending into the tube, its weight being assisted by
that of the air above it. The value of this plan is,
iliat moisture and air are completely expelled from
the bulb and tube.
Another plan is to blow two bulbs on the tube in-
stead of one, as shown in Fig. 2159, one near the
extremity, and the‘ other near the other end. The

Fig. 21-59.
‘latter bulb is heated so as torexpel a portion of the
'air, and the open 'end- just beyond it is immersed in
pure mercury. As the glass ‘cools, a portion of the
metal is pressed up into that ‘bulb. The tube is then
held with the bulb at the other end downwards, and
this latter bulb is heated, the air rarefied, and partly '
expelled through the mercury, a portion of which is
afterwards pressed down into the lower bulb, when it
‘has cooled. In this way the bulb at the end of the
‘tube is entirely filled, and a portion of the mercury is
left in the other bulb. The tube is now held by a
piece of iron wire over a charcoal fire, and heated so
as to vaporize part of the mercury, by which means
air and moisture are expelled: the open end is then
‘closed with wax, and the tube removed from the fire : .
‘on inclining it, a portion of the mercury falls into the
‘stem from the upper bulb, and it is made to settle at -
the desired height. If too much, or not enough, mer-
cury be in the lower bulb and stem, portions of it can -
be transferred to or from the other bulb by inclining
the stem to one side or the other. The adjustment
being made, the flame of a blow-pipe is applied a little
below the upper bulb, and the tube is permanently
closed and detached from the upper bulb, as shown in
the figure. By the other methods of filling, the tube
is finally closed by first gently heating the mercury in
the bulb until it rises to the point at which the sealing
‘is ‘to be made. The excess of mercury which filled

the tube, when cold, is thus expelled, and the bulb
and tube still left full of mercury at the increased
temperature. The tube is softened by the flame of a
blow-pipe, the heat from the bulb being removed, and
the stem is thus hermetically sealed by the fusion of
the glass at the end.
As the indications of the thermometer depend on
the rise and fall of the mercury in the tube, the bulb
and a portion only of the stem must remain filled after
the sealing and cooling of the tube, so that in any
depression of the mercury by cold there shall still be
a portion of the mercury in the stem to indicate its
amount, and that, in expanding by heat, the tube
should be sufiiciently long to allow the utmost range
to the metal, while no other fluid should be above it
to counteract its ascensive force. A good test of the
absence of air and moisture, as well as of the purity of
the metal, is to invert the tube, when, unless the bore
be very small, the mercury should fall easily to the
sealed end, so as to occupy the whole of the bore.
Supposing 'a number of tubes to have been filled, a
graduated scale is attached to each by first finding
a fixed point for each tube, if of moderate range, and
two fixed points if the range be above the boiling point
of water. If the tubes be placed in a vessel contain-
. ing melting snow or ice, the mercury will sink in each
stem down to a certain point, at which it will remain
stationary during the whole of the liquefaction. [See
HEAT] The height of the mercury may not corre-
: spond in any two stems, but each stem will have its
: own fixed point peculiar to itself; the amount of de-
: pression of the mercury depending, let, on the tem-
, perature of melting ice or snow, which is constant;
' 2d, on the size of the bulb compared with the stem,
i which may be variable in each case; 3d, on the quan-
tity of mercury enclosed in the bulb and stem, which
may also be variable. A scratch is made with a file
on the outside of the tube, exactly opposite the point
at which the column of mercury terminates. This is
called the freezing point, or temperature of melting
ice, and is the same in every part of the world, at
every season of the year, and is not influenced by
.the temperature of the apartment in which the gra-
duation is conducted.
The determination of the boiling point is more
difiicult, because it is subject to variation with the
variations in atmospheric pressure. [See EBULLI-
TION.] But supposing the barometer to mark 30
inches, or mean pressure, the boiling point of pure
water would be constantly 212°. But whatever the
pressure, it a number of thermometer tubes be sus-
pended in a vessel of water which is being heated, the
mercury in each tube will gradually rise in proportion
as the temperature of the water rises : but the mo-
ment it begins to boil, the mercury will cease to rise :
it will remain stationary until the whole of the water
has evaporated. A mark made opposite the end of
the mercury in the tube will thus give the water
boiling point of the thermometer in each case. This
may also stand at difierent heights in difierent tubes,
for similar reasons to those given in the case of the
freezing point. i
THIERllTOMdlTfi.
835
A Committee appointed by the Royal Society about
the middle of the last century, to inquire into the
principles which regulate the construction of the
thermometer, recommended that the boiling point be
fixed when the barometer stands at 2980 inches ; that
the bulb be not immersed in the water, because they
found that according to the depth of the immersion
the mercury rose in the tube, the steam in fact being
in such case under a slight increase of pressure.
They recommend as a boiler a vessel of tinned iron,
with an easily fitting cover rendered steam-tight by
a ring of woollen cloth 3 the cover to have 2 apertures,
one to act as a chimney with an area of not less than
half a square inch, and about 3 inches high, to convey
away the steam from the boiling water, and the other
hole for a cork through which the thermometer-stem
is to pass in such a manner that the bulb shall not
touch the surface of the water, but be surrounded
with steam: no more of the stem is to be exposed
above the cork than is necessary to show the height
of the mercury when the water is boiling briskly.
When matters are thus adjusted, a thin plate of metal
is to be placed over the chimney to prevent the escape
of the steam ; heat is applied to the bottom of the
boiler, and when the mercury has risen to the temper-
ature of the steam it is to be allowed to remain at
rest for a few minutes, and then its height is to be
accurately marked with a file.
When the barometer does not stand at 29'80 in.,
the boiling point may still be adjusted to that pressure
by means of a table of corrections of which the follow-
ing is a portion :--
Thermometer immersed Correction in 1,000 th
In Steam. In Water. of the interval between
Height of Height of freezing and boiling
Barometer. Barometer. points.
30'60 10
'50 9
30'71 ‘41 8
'50 '29 7
'48 '18 6
-37 '07 5 Lower.
‘25 ‘95 4
'14 '84 3
'03 '73 2
29'91 '61 l
'80 '50 0
29'69 29'39 l \
'58 '28 2
'47 'l 7 3
'36 '06 4
25 28 95 5
14 '84 6 > Higher.
03 '73 7
28-92 ‘62 8
'81 51 9
~70 10 1

It has been observed that mercurial thermometers
slowly change their fixed points, in consequence, it is
supposed, of a diminished capacity of the bulb, due
to the atmospheric pressure constantly exerted on its
exterior and not counterbalanced by an equal pressure
from within. Professor Daniell examined two ther-
mometers constructed with much care by the Hon.
Henry Cavendish. “The mercury in the balls of
both flows freely into the tubes when reversed; and
when suffered to fall sharply, strikes the end with a
metallic sound. The same click may be heard in the

bulbs when it is permitted to fall back, and the cavit y
closes without the slightest speck. They are mounted
upon common deal sticks, and the graduation, which
is only continued for a few degrees above the freezing
point, is engraved upon a small slip of brass. The
degrees are very large, and they are distinctly divided
into tenths. Each degree of No. 1 occupies a space
of ‘208 inch, and of No. 2, ‘130 inch. The scratch
upon the glass for the freezing point is very visible
in both. It is difficult to say for what purpose they
were originally made, but evidently for some experi-
ments upon the freezing point of water; and if they
had been expressly constructed to verify the present
point, they could not have been better contrived for
the purpose. The bulbs of both were plunged into
pounded ice, in which they were left for half an hour,
and the height of the mercury was carefully taken by
two observers with the aid of magnifying glasses.
The result of the examination was that in No. 1 the
freezing point upon the scale was 0'41“ too low, and
in No. 2, 0'35". There can be little doubt, I think,
that the right cause of the phenomenon has been
assigned, viz. the change of form and capacity which
the glass undergoes from the pressure of the atmo-
sphere upon the vacuum of the tube.” 1
The principal amount of contraction of mercurial
thermometers takes place soon after the tube is sealed :
and hence it has been recommended to allow 10 0112
months to elapse between the sealing and the gradua-
tion of a thermometer.
The freezing and boiling points having been fixed,
the interval between the two includes that portion of
the tube which corresponds to the expansion of the
mercury between these two temperatures; and since
this expansion is constant, it follows that the propor—
tion which the capacity of the tube between these
two points bears to the volume of mercury included
in the instrument at the temperature of melting ice
must be constant also. The capacity, therefore, of
the tube between the above points will be propor-
tional to the capacities of the bulb and stem below
the freezing point. This is a consequence of the
uniform expansion of mercury when subjected to the
same limits of temperature. Now between the boiling
and freezing points of water the expansion of mercury
amounts to gzg'rgth part of the volume which it occu-
pics at the temperature of melting ice; therefore the
capacity of the tube between the two fixed points
must always be equal to 3%.3'th part of the capacity
of the bulb together with that portion of the stem
below the freezing point. The varying lengths,
therefore, of the intervals between the two fixed
points in different thermometers will be found to arise
from the different proportions which the capacity
of the bulb bears to the bore of the stern. Hence a
plan is sometimes adopted inwarm climates where ice
and snow are unknown, of graduating the thermometer

(1) “ Elements of Meteorology,” v01. 1845. It should also be
stated that Bellani attributed the cause of this remarkable pheno-
menon to molecular action, meaning thereby that a considerable
time elapses before the particles of glass assume their final posi-
tions after the bulb is blown.
3H2
836
'THERMOMETER.
by means of the boiling point alone. For this purpose
the stem is graduated by means of a drop of mercury
of known weight, which is moved about in various
parts of the tube; a bulb is then blown upon one end
of the stem, and mercury is introduced in the usual
manner, the quantity of which is seen ‘ately weighed;
and since the space between 32° and 212° corresponds
to an expansion of mercury equal to 1oqlmth, the
number of graduated spaces between the boiling and
the freezing points may be computed. Thus, suppose
the weight of the included mercury to be 333 grains:
then 7r,‘mth of that quantity, or 0 grains, corresponds
to 180° of Fahrenheit’s scale. If the initial measur-
ing column were 06 of a grain, then 10 of those
spaces would comprehend the range between freezing
and boiling water. Hence if the boiling point is
known, the freezing point can be set off;
Q I each space being successively occupied by
‘fire. the drop of mercury into 18 equal parts
or degrees.
The Florentine Academicians directed
that the principal divisions of the tube
should be marked “ by a little button of
white enamel; and these may be further
subdivided ‘by the eye, and the interme-
diate degrees marked by buttons of glass,
or of black enamel.” The Florentine
thermometer is represented in Fig. 2160.
It is still the custom, in chemical ther-
mometers, for example, which have to be
plunged into corrosive liquids, to mark



lower part of the separate scale is made
to fold up on a hinge, so that the bulb
and a small portion of the stem may be
immersed in liquids without injury to the scale.
Fig. 2160.
But the usual method is, when the tube has the two '
fixed points marked upon it, to attach it firmly to a
frame of hard dry wood, such as box-
wood, as in Fig. 2161, or of metal,
ivory or glass. Opposite to the freez-
and the space between the two is di-
vided into 180 equal parts or (Zcyrces;
the space between any two degrees
depending on the space between the
boiling and freezing points. These de-
grees are continued above and below
the two fixed points, the numeration
point and reckoning upwards; so that
the boiling point is 212°.1 This is
Fahrenheit’s scale. By immersing the
bulb in a mixture of salt and snow, he
caused the mercury to sink to a point
which he erroneously supposed to in-
dicate the greatest amount of cold that
could be produced, and from such point
he commenced his scale, calling it zero



Fig. 2161.

(l) Messrs. Mackenzie 8.5 Blair, of Glasgow, have patented a
thermometer-scale printed on vulcanized india-rubber, in order
“that such scale surfaces may be elongated or allowed to con-
thc graduations on the stem itself ; or the ,
ing and boiling points a line is engraved, '
commencing 32° below the freezing

or 0°; between this temperature and that of melting
ice he marked 32°, and by continuing to divide his
scale equally he arrived at the 212th degree, or the
boiling point of water. But when tcmperatru'es were
discovered below zero, and it was necessary to con-
tinue the scale downwards, the negative sign —- was
prefixed to each degree, thus involving the absurdity
of negative signs for positive quantities; for a tem-
perature below zero is as much a positive quantity as
a temperature above that point. The number of de-
grees above zero has for a prefix the positive sign +.
Thus -— 10° signifies 10° below zero, and + 10° im-
plies 10° above zero.
Fahrenheit’s scale is not used in France. Previous
to the Revolution, Réaumur’s scale was adopted.
Réaumur used spirits of wine in his thermometer;
but De Luc substituted mercury. The fixed points
on this scale were the same as on Fahrenheit’s ; but
the numeration commenced from the freezing point,
which was zero. The interval between the two fixed
points was divided into 80 equal parts, so that the
boiling point was 30°, and a degree on this scale was
longer than one on Fahrenheit’s in the proportion of
2% to 1. To‘ convert a temperature on ltéaumur’s
scale into a corresponding one on Fahrenheit’s it is
necessary to multiply Réaumur’s degrees by 2;}, and
to add to the product 32° to allow for the distance of
the points at which the scale commences. For ex-
examplez-
Réuumur. Fahrenheit,
16°>< 9==144+ 4== sc°+ s2°=cs°
80° x 9 == 720 + 4 =lsc°+ 32°= 212°
To reduce a degree of Fahrenheit’s to one of Réau-
mur, 32° must be subtracted, and the remainder
diminished in the proportion of 271~ to 1. For ex-
ample :—
Fahrenhcit. Réaumur.
cs°- 32°= as x 4=144+ a: 16°
212°- 32°=1s0 >< 4 = 720 + 9 = 80°
In 17112, the Swedish astronomer Celsius contrived
a thermometer, the scale of which also commenced at
the freezing point of water, and the interval between
that and the boiling point was divided into 100°.
Thisthermometer was adopted by the French during
the Revolution, under the name of T/iermometre Ccuti-
grua’c, because it harmonized with their decimal sys-
tem of weights and measures. Every one of its degrees
is equal to 1%ths of a degree of Fahrenheit; for 100°
of the former are equal to 130° of the latter. To
convert a tcnmerature in Centigrade to the corre-

tract at pleasure, to assist in their adjustment to varying lengths
comprehended between any two fixed points. The lines of gra»
duation with their corresponding references are set up in type,
and impressions are then taken from this form upon the elastic
sheets, either when the latter are slightly elongated, or in their
natural condition of tension.” The freezing and boiling points
having been marked on the tube, “the elastic scale may be
stretched to bring the freezing and boiling graduations thereon to
correspond exactly with the tube marks; and if the elastic mate“
rial is of uniform width, thickness, and elasticity, all the interme-
diate graduations will be found to agree with their corresponding
lines oi‘ mercurial traverse in the tube. Vulcaniscd caoutchouc is
not materially affected by thermal or atmospheric changes, and
when soiled it may be washed." The references beingr printed on
the elastic scales, :1 much larger number can be inserted in small
type than when thcyare engraved by hand- '
rnnnMoMirrna.
-837
spending temperature on Fahrenheit, the number of
degrees must be increased in the proportion of 100 to
180, (which is the same as 5 : 9,) and 32° added to
the result. To reduce a degree of Fahrenheit to one
of Centigrade, 32° must be subtracted, and the remain-
der diminished in the proportion of 9 to 5. For ex-
ample :—
Pa‘ir. Cent.
212°—32=180 x 5:900 —:- 9=100°
Cent. Fahr.
100 x 9=900+5=180+32=212°
In Delisle’s scale, used in Russia, the boiling point
is 0° and the freezing 150°. Other scales have been
proposed, but do not require notice here.
When a thermometer is exposed to heat, not only
does the mercury expand, but also the bulb and stem
which contain it. By a fortunate coincidence, how-
ever, the expansion of the glass is in proportion to
that of the mercury; and therefore the change of
volume in the mercury bears a constant proportion to
the change of capacity in the glass. Hence the vari-
ation in the height of the column of mercury must
bear the same proportion to the variations which it
would experience if the glass were not subject to ex—
pansion or contraction. 1f the mercury and the glass
expanded equally with equal chariges of temperature,
the column of mercury would not appear to rise or
fall, but would always be stationary. But as the
change of bulk in the glass bears a very small though
constant proportion to the change in bulk of the
mercury, the expansion of the former does not afford
space for the increased volume of the latter, and the
mercury therefore is forced up the tube; or vice versa”.
Hence the variation of the column of mercury arises
from the difference of expansion between the mercury
and the glass, and this difference, from the freezing
up to the boiling point, amounts to 3%.gtll. of the ve-
lume of mercury at 32°. Different kinds of glass
expand in different proportions; but all expand pro-
portionally to each other and to mercury; and as
during the graduation of the thermometer, at the
freezing and boiling points, the glass is affected in a
manner which is not subject to change in the sub-
sequent practical application of the instrument, it
follows that the indications of the columns of mercury
may be regarded without reference to the change of
bulk of the glass in which the mercury is contained.
It has been stated that the expansion of mercury
between 32° and 212° is nearly equal for equal incre-
ments of temperature. Above this, the increasing
rate of the expansion of mercury becomes sensible, by
exposing a mercurial and an air thermometer (the
expansion of air being apparently perfectly equable)
to the same temperature; taking care to correct the
instruments for the expansion of glass. The following
table gives the points on the two scales resulting
from the same temperatures :—
Au' Mercu ial
Thermometer. T hcrmometer Difference
212 ° 212° 0°
299'66 302 2'33
386-69 392 5 '31
473‘09 482 8'91
558'86 572 I3'M-
662 680 18110

Thus it appears that the boiling point of mercury,
as measured by its own expansion, is 680°; but by
the expansion of air 662°. If a common thermometer
be plunged into boiling mercury, it stands at 660°: so
that the expansion of the glass is equal to 20°, and
almost exactly counteracts the increase of the rate of
expansion of the mercury. Hence an accurately gra-
duated mercurial glass thermometer becomes, by this
fortunate coincidence, an accurate measurer of the
increase of temperature as high as the boiling point of
mercury, or about 660° or 662°.
For measuring temperatures below the freezing
point of mercury, a spirit thermometer is used, alcohol
not congealing by any reduction of temperaturehitherto
observed. [SeeALcoHon] The expansion of this liquid,
when uniform, may evidently be made to correspond
with the degrees on the mercurial thermometer. For
low temperatures its indications are .to be relied on ;
but as it approaches its boiling point, or 176°, its
rate of expansion is not uniform; indeed, it cannot
be safely trusted above 100° Fahr.
For estimating temperatures above the boiling
point of mercury, an air thermometer is sometimes
used. Dry air, when confined in such a manner as
always to preserve the same expansive force, increases
in volume gths for every 180°, and since its progres-
sive rate of expansion is sensibly uniform for equal
increments of heat, an instrument has been constructed
in the following manner :—A bulb, or cylinder, with
a tube of platinum, is formed similar in shape to that
of the common thermometer; and connected with
the extremity of the stem 01' tube, at right angles, is
a glass tube of uniform bore, filled with mercury and
terminating below in a recurved bulb, The glass tube
is graduated into a series of spaces, each equivalent
to gths of the total volume of the platinum bulb or
cylinder with fifths of its stem. The other fourth is
supposed to be hardly influenced by the source of heat.
The platinum bulb or cylinder, and %ds of its stem,
are to be plunged into a fru‘nace, and the depression
of the mercury by the heated and expanded air within
the instrument (pressing on it more powerfully than
the external air) will indicate the degree of tem-
perature.
High temperatures were formerly expressed by the
degrees of Wedgwood’s Barometer, an instrument con-
structed on a fallacious principle, and therefore fallen
into disuse among accurate observers. But as it is
still sometimes referred to by persons who write on
science without ever having gone through any expe-
rimental training, it may be desirable to state wherein
the error of this instrument consists. When clay is
exposed to a high temperature it undergoes a per-
manent diminution both of bulk and weight in con-
sequence of the expulsion of water from its pores.
[See ALUMINA—CLAY.] Wedgwood further sup-
posed that this contraction was always proportional
to the highest temperature to which the clay had
been exposed. But this is now known to be an error,
since the exposure to a lower heat for a longer time
will produce as much contraction as the exposure to
a more intense heat for a shorter time. The indica-
838
THERMOMETER.
tions of this instrument therefore are quite useless.
They were obtained by exposing small cylinders of
very pure clay, about % inch in diameter, to the heat
intended to be measured, and afterwards when cold
measuring their contraction very accurately by observ-
ing how much further than before they would slide
along a groove left between two perfectly straight
brass rulers fixed on a board so as to be rather nearer
together at one end than at the other, a scale being
marked on one of these rulers.
When the fallacy of this instrument became
known, many attempts were made to apply the
expansions of other solids, such as metals, to the
measurement of high degrees of heat, but without
success, the chief difficulty arising from the fact of
the expansion being only temporary, and taking place
while the metal was in the furnace, and of course
beyond the reach of observation. It was necessary
therefore to make it register its own expansion by
some mark that would remain when it was cold.
This was first satisfactorily effected by Professor
Daniell in a pyrometer represented in Fig. 2162, con-
sisting of two distinct parts, the scale, No. 1, and
the register, No. 2. The register is a solid bar of
blacklead earthenware, D D, No. 2, 8 inches long,
T’aths of an inch wide, and of the same thickness.
A cavity 0 is drilled down this, ia-oths inch in diameter,
and 7 :1; inches deep. At the top of the bar and on
the nearer side at 1910, about &ths inch in length of
its substance is cut away to the depth of half the
diameter of the bore. When a bar of any metal 6%
inches long is dropped into this cavity, it rests against
the solid end of the bar; and a cylindrical piece of
porcelain 99, about 1% inch long, serving for the
index, is placed upon the top of it, which index being
partly in and partly out of the cavity in the bar, is
kept firmly in its place by a band of platinum r,
which is tightened by a small wedge s. It is obvious
that when such an arrangement is exposed to a high
temperature, the metallic bar in the cavityo will force
the index 9 9 forward to the amount of the excess of
its expansion over that of the blacklead; and that
when again cooled it will be left at the point of
greatest elongation. The contraction which the black-
lead clay may suffer from the great heat is not likely
to lead to any fallacy; as the greatest expansion of
the metal will have been completed at the point of
time when its earthenware case may slightly contract,
and the index will still mark the point of the furthest
extension.
The contrivance by which the expansion of the
metal is measured must now be noticed. The amount
is in all cases small, but it is rendered more per-
ceptible by the means employed. The application of
the scale to the register must be made before the
exposure of the latter to the fire, and also after its
cooling: and the object sought is to ascertain pre-
cisely how much the index 4,: q is pushed out by the
expansion of the metal when heated. The scale is
made of two rules of brass, accurately joined together
by a right angle at one of their long edges, and fitting
square upon two sides of the blacklead bar, and of

about half its length. The greater rule is AA, No. 1,
and the smaller, or, as it is called, the frame a aw’, fits
on the under side of AA, and is adjusted by the
screws 5 6. When the scale is thus fitted to the re-
gister, the projecting piece of brass a’ rests upon the

M a
m, f v@
0 i i‘
mqe» _. __‘_. =~ "' l [H !__i"l_||l_lb,\ _»
B _ ‘ m 'vnHm i.
h






DANIELL’S PYROMETER.
Fig. 2162.
ledge under the platinum band r; so that in this
way the scale is firmly united to the register. At
the upper extremity of this frame is fixed an appa-
ratus, which corresponds to a pair of proportional com-
passes, the whole of which is movable at a screw 0 d,
which part projects so as to come exactly over the
hole in the register. The connexion of the two arms
13 c is made by a screw below f The arm B, which is
5,},- inches long, carries an arc of a circle 66 whose
radius fg is 5 inches; this are is graduated into
degrees and thirds, subdivided by the vernier 9 into
minutes, which may be read off by the magnifying
glass at z', the stem of which lies on the bar 0 between
is and l, and is so arranged as to bend twice in order
that the glass may project horizontally over the
vernier. The other end of the lighter arm 0 termi—
nates in a point lz, which is 1i inch from f; or 3% th of
the radius fe. At m is a steel spring fixed in a cavity
cut out of the arm B; it exerts a pressure on a small
pin 12 in the arm 0, and throws the radius back to the
commencement of the are. In making a measure~
ment this point It is fixed into a small hole in the
index at Q. When this is effected, the part 71. f acts as
the smaller arm of a lever, and the radius f y will point
to a degree on the are e a different from that to which
it pointed on the previous application of this apparatus
THERMOMETER.
839
to the bar before it was heated; hence, the are de-
scribed by the point h is increased tenfold on the
segment at e e. The small are is of course due to the
index at q 9 having been pushed out when the metal
expanded, which are is thus appreciated by taking its
decuple. The chords of these arcs are easily found by
computation, and that of the smaller gives the amount
of the advance of the index, or of the expansion of
the metal. The degrees given on this scale are made
to bear relation to those of the mercurial scale; so
that as the ratio is marked on the instrument, the
degrees of the scale are convertible into those of
Fahrenheit.
One advantage of this pyrometer is, that the
material whose expansion is to be measured is quite
detached during the heating process from the instru-
ment of measurement ; so that the scale, vernier, 820.
not being exposed to the fire, are not subject to an
expansion which would interfere with the correctness
of the results.
Professor Daniell in his account of this instrument 1
gives the rule for calculating the linear expansion of
the metal bar, by means of the are described by the
smaller divisions of the graduated arm. We must
refer to the original memoir for these details ; but the
following are given as the elongations of a bar of
platinum 0% inches long, and the corresponding
changes of temperature indicated by a displacement
of the index through various small arcs. The first
column shows the are; the second the linear expan-
sion of the bar of metal; and the third, the tem-
perature z—thus if the radius move 1°, the bar is
elongated ‘00872 of an inch, and the temperature
is 450°.
Arc. Elongation. Temperature.
1° 0’ = ‘00872 Inch = 450"
0 so = '00436 ,, = 225
0 20 = ‘00290 ,, = 150
0 15 = ‘00218 ,, = 112
0 10 = ‘00145 ,, = 75
0 5 = ‘00072 ,, = 37
0 2 = ‘00029 ,, = 15
o 1 = -00014 ,, = 7-5
Some of the results obtained by Daniell’s pyrometer
are given in the table which accompanies the article
HEAT. By an arrangement shown in No. 3, Fig.
2162, bars of metal can be exposed to the vapour of
mercury. a is an iron tube, 2 inches in diameter,
closed at the bottom; 6 is a blacklead tube, closed at
the top, and fitted to the mouth of a by grinding; c is
a smaller blacklead tube, projecting from the side of
the latter, and fitted by grinding. This arrangement
forms a kind of alembic in which mercury may be
boiled, and the expansion of bars of metal taken at
that temperature. The results obtained in this way
were found to be in very close agreement with those
obtained by some of the best French experimentalists.
Several different forms of pyrometers, or thermo-
meters of solid substances have been constructed by
Breguet of Paris. One of them depends on a principle
that has often been applied in the construction of
compensation pendulums, balance wheels, 85s., [see

(1) Philosophical Transactions for 1830.

HonoLoeY,] viz. that if two flat bars or plates of
different metals, such as steel and brass, be placed
face to face and riveted or otherwise fastened to—
gether near their ends, as in Fig.2163, this compound
bar will remain flat only so long as the temperature
is unaltered. An exposure to a higher temperature
will cause it to warp or bend, in consequence of the
more expansible metal, brass, becoming longer than the


Fig. 2163.
other, and therefore becoming convex, as in No. 3,
while a diminution of temperature will produce a
curvature the other way, as in No. 2, for the metal
which expanded most will also contract most, and
so become concave. It is obvious that these cur~
vatures will be produced with less strain and be
more perfect if there be introduced between the two
metals a third of
intermediate ex-
pansibility. In , I
Breguet’s ther- '
mometer or pyro-
meter, a slip of
gold is interposed
between 2 slips
of platinum and
silver, and the
combined layer is
then drawn to a
great degree of saw“
é 1"‘ npunnfli‘mlmmx irlfii‘ziuihm Ia
» 1









thinness, being: _ _
— 1%
only . 12100 of :_:$Ii-“='— - :‘
an inch ; after _-——
which it is curved ‘" — ._. 5::
into the Spiral Fig. 2164. semester’: PYROMETER.
form, as in Fig. 2164:, with an index at the bottom
turning round a graduated circle. When this coil or
spiral is heated, it tends to unbend, and this is
rendered perceptible by the lower end, to which the
index is attached, moving slowly round to accommo-
date itself to its less curved state; and thus the
degree of unbending may be measured with the aid
of the graduated circle.
Thermometers of various constructions have at
different times been invented for marking the highest
and the lowest degrees of temperature which may
occur in the absence of the observer. Such instru-
ments are called Register Thermometers. The Day and
Night Thermometer of Dr. John Rutherford consists
of a mercury and a spirit thermometer, each provided
with its own scale. The stems are placed horizontally,
or at an angle inclining a few degrees upwards, and
the bulbs are at right angles to the stems. Both
thermometers may be mounted on the same frame, or
8&0"
THERMOMETER.


they may be separate, as in Figs. 2165, 2166. To
register the highest temperature between the times of
observation, a piece of steel 2', such as a fragment of a
sewing-needle, is placed within the stem of the mer-
cury thermometer, and as the mercury expands, it
pushes this piece of steel before it; but if after this
the mercury fall, the steel is left behind to mark the
point of greatest expansion. To register the lowest
temperature, a cylinder of white enamel, with a small
knob at each end, is enclosed in the stem of the spirit
1*.“- .
‘In;
iflrlr-I
Han...


Figs. 2165, 2166. RUTHERFORD’S REGISTER
:rnnniuomsrnns.
thermometer; when the spirit is contracted by cold,
the attraction between the last film of the column of
spirit and the enamel is sufi'icient to overcome the
' slight friction-of the latter on the inside of the tube,
and to draw it backwards in the direction of the
bulb; but if the spirit begin again to expand, it
passes the enamel without pushing it forward; and
the lowest degree of temperature is thus registered.
0 To adjust the instrument
for a fresh observation, it
must be inclined, so as to
bring the register marks to
_ the respective surfaces of
0 the two fluids; should
there be any difiiculty in
this, (which there is not in
,a well-made instrument,)
the head of the enamel
furthest from the spirit
may be made of steel; and
then both thermometers
may be adjusted by_means
of a small magnet applied
to the outside of the stem.
In 1782, Mr. Six con-
structed a self—registering
. - thermometer. It has been
modified since that time,
and the following is a good
form. A, Fig. 2167, is a
tube or long bulb, filled
with alcohol, and connected
‘(0
O
_ :__.a __ - rr -_,-;_.1__-n.. -. ‘
‘-—"-—~.____-_:~-‘- . 5 KY, . _.
_~___
60
_ \
6'0
l,
70- gl
1» I?"'~‘r?":'_-“~"="" - w‘
' ‘7.’. !‘4:'*'.'.'t;r;z_'_::3'-~‘_~C__' -.v a.
a ,.-A .------__-..~‘ gr».
M V. *W
:5
ti‘
so ~ ‘A
l t
#1.
90 - if
10_
Q
I1 -:'
Lgi
if‘;
5'.
1;
E?‘
n

Q
[2
ma -°
.4
in
‘l, ‘l
also filled with alcohol
down to the point 472,
where the mercury com-
mences; this is continued round the lower bend to
the point m’, where alcohol again commences and con-
tinues up to the top, partly filling the bulb b, a per--



by a bend with a tube m m’
{'I
“ii I
Fig. 2167. srx’s nnerscrnn
Tnnnuomnrnn,

tion of which is left 'empty to allow space for the
expansion of the liquid. Two indices 2' and ‘z' are im-
mersed in the alcohol just above the surface of the
mercury in the two exterior tubes. These indices are
of steel coated with glass, and finished at each end
with a spot of enamel. To prevent them from mov-
ing through the alcohol by their own weight, a spring
of glass or of bristle is attached to them, which by
being somewhat bent presses lightly against the in~
terior of the tube, as shown on a larger scale in the
figures at the side. If the highest and lowest tem-
peratures which occur during the absence of the
observer be required, he first adjusts the instrument
by drawing down the indices 'to the two surfaces of
the mercury by means of a magnet. Suppose then
that the temperature increases during the absence of
the observer ; the alcohol in the bulb A expands and
presses down the mercury at m, which of course
occasions a rise at m’, by which the index ‘z’ is raised.
Any subsequent depression of temperature will lower
the surface m, but cannot lower the index ‘2', which
clings to the sides of the tube. The greatest increase
of temperature during the observer’s absence is de-
noted by the position of the index ‘2'; and a scale of
degrees attached to the instrument measures that
change. But if the temperature fall, the alcohol
contracts; and the mercury rises at m, pushing the
index 1.’ before it; from which position it likewise
cannot again recede, however much the temperature
may afterwards increase. A scale measures that
change of position as before, and the application of a
magnet will again prepare the instrument for another
observation.
Other forms of thermometers have been proposed
for particular purposes, of which two or three examples
may be given.




Many years ago Dr. "" ,
Cummings of Chester in-
f
vented a thermometer for , l;
opening and shutting the
door or window of a hot~
house or other apartment
when the temperature had
attained a certain point.
It consisted of a large
glass or iron matrass m
Fig. 2168 filled with air, I 7m“
but with mercury in its
stem, which was inverted
in a cistern 0 containing
the same fluid. The ma—
trass was connected by a
cord with the sash of a
window 20, or of a venti— _.|. lator v; the cord passed over pulleys 121/12", and if i
the weight of the matrass
was so adjusted that it nearly balanced the weight of
the sash or ventilator. ,When the increase of tem-
perature expanded the air in the matrass, a portion of
the mercury was driven out of the stem, so that the
matrass became lighter than before, and thus not an








1 llllllll


Fig. 2168.
THERMOMETER.
841
equal balance for the window-sash or ventilator,
which was thus let down from the top; and so a
communication with the external air could be either
established or cut off, according as the temperature of
the room affected the air in the matrass. A similar
principle was applied by Dr. Arnott to the construc-
tion of a self-registering stove. See WARMING and
VENTILATION.
An instrument called a lfiermomelrz'e almwm was
shown in Class X. of the Great Exhibition. It con-
sisted of a bent glass tube with a bulb at each end,
one of which with a part of the stem contained ether,
and the other, which was open to the external air, a
certain quantity of mercury, which also occupied a
part of the stem. The tube was poised on its centre
of gravity; but if, from any cause, the temperature
should rise, as in the case of an accidental fire, the
expansion of the ether would drive the whole of the
mercury into the open bulb, cause it to tip over and
discharge an alarum. Balance lfiermomelers are by no
means new. One was patented in 1816 by Mr. Kew—
ley, and was employed to shut and open doors ac—
cording to the temperature of the apartment.
l/Ve will now briefly describe the principle of the
seeonrl class into which we have distinguished Thermo—
metrical Instruments. Their object is to compare
the total quantities of the cause of lzeal, which are
given out in the cooling of known quantities of dif-
ferent substances through a given number of degrees,
or in the chemical action of given quantities of
different materials. Hence the name calorimeter or
measurer of calorie.
The calorimeter, Fig. 2169, was invented by
Lavoisier and Laplace. It consists of 3 concentric
metallic vessels, s c E, completely enclosed one within
another, and con-
nected by as few
supports as possible.
When used for de-
termining the speci-
fic heats of bodies
as mentioned under
HEAT, the tempe-
rature of the air
must not be higher
than 40°, nor so low
as 32°. The two
outer compartments
are filled with
broken ice, which is
of course in a melt-
ing state, and therefore maintains a constant tempera-
ture of 32°, although constantly receiving heat both
from the external air and from the innermost vessel.
When therefore the substance to be examined is
heated and placed in the inner vessel E, all the heat
which it gives out is employed in melting the ice
which immediately surrounds it ; the resulting water
is allowed to drain through a pipe cl from the bottom,
and being carefully collected and weighed, shows
how much ice has been melted (without raising its



CALORIMETB R.-
.Fig, 2169.
temperature), or how much water might have been

raised 1et0° by the cooling of the substance ex-
amined, through a known number of degrees—for
no heat could penetrate to this ice from the ex-
ternal air, because all the heat that enters the calo—
rimeter from without is employed in melting the ice
of the outer vessel, which drains through a. separate
pipe cl’, and is not allowed to mix with the drainage
of the inner ice. In fact, as long as the two outer
vessels are kept constantly supplied with melting ice
from the top, they form a perfectly insulating wall,
through which no heat can pass, for as ice cannot
exist above the temperature of 32°, whatever heat
enters it must be employed in melting the first layer,
and can proceed no further, if that layer be renewed.
The use of this instrument requires great care that
the quantities of water retained in the interstices of
the broken ice by capillary attraction may be equal
before and after the experiment; otherwise great
errors will be introduced by this cause.
By similar contrivances various observers have
measured the relative quantities of heat evolved by
the combustion of different kinds of fuel. The results
are usually expressed by the number of pounds of ice
that could be melted (or of water that could be
warmed 14:00) by the combustion of one pound of the
fuel. The following table shows a few of these results
as obtained by Dr. Dalton and by Count Rumford.
The second column shows the weight of oxygen
necessary to support the combustion of one pound of
the fuel; by which it will be seen that the more
oxygen is consumed, the more heat is in general pro—
duced.
Fuel of which one Lbs. of oxygen Lbs. of ice
pound is burned. consumed. melted-
Hydrogen \ .. ... 8 . . . . .. 320
Light carburetted hydrogen . . . . .. 4- . . . . .. 88
Heavy earburetted hydrogen . . . . .. 3'5 . . . . .. 85
Carbon . . . . . . . .. 2'66 . . . . .. 40
Wax . 3'14: . . . . .. 126
Tallow 3'1 , . . . . .. 111
Ether .. 2'6 . . . . .. 107
Naphtha. . 3'33 . . . . .. 97
Olive oil ... ... 3 . . . . .. 93
Alcohol ... 2'1 . . . . .. 58
The first four results, which are by Dalton, would
furnish the means of calculating the heating effect of
all available kinds of fuel, were it not that they were
unfortunately obtained by an imperfect method, in
which much of the heat was unavoidably lost. They
must only be compared among themselves, therefore,
being proportionally lower than the other determina-
tions by Count Rumford.
It has been calculated by M. Pouillet, that the
daily amount of solar heat received by the earth
would suffice to melt a layer of ice averaging, over
the whole earth, 1% inch thick. As the average weight
of such a layer would be about 65;- lbs. per square
yard, it follows that the heat received daily is equiva-
lent to that which would result from the burning
of 26 oz. of carbon, for every square yard of the
earth’s surface; or as another illustration, the mean
amount of heat radiated daily from the sun upon
every acre of land in this latitude, is equal to that
which would be emitted during the combustion of
sixty sacks of coals.
842
THERMOMETER.
The flair-a? kind of thermometers are those intended
to measure radiant Izeazf. . In order to do this without
employing time as an element of the observation, it
must evidently be necessary to have only part of the
instrument exposed to the heating rays, and part
shielded from them, and then to measure the difference
of temperature between these two parts. The instru-
ment should measure this difference only, and should
be unaffected by any change of temperature taking
place in both parts equally.
The first instrument invented for this purpose was
the da'flerential thermometer of Leslie, represented in
Fig. 2170. It' consists of a glass tube, bent into the
, _ _ form of the letter
U, with a bulb
1 ‘ A’ at each extremity
containing air.
The tube contains
sulphuric acid
(freezing point
0°, boiling point
605°),tinged with
carmine; and it
is supported on a
stand, as shown
in the figure.
In order to un-
derstand the ac-
tion of this in-




i... ._ _ ..D________;~_,_:'lnt}


.-._:_..
“Mm—#7:. ‘ 2
*4
, I", ,
i‘. H
"i y‘,






“w,




1:.
~__.___.__.____
.__ _._ .._.=
strument, we
must refer to
what has been
F29. 2170. DIFFERENTIAL TnnnMoMn'rnx. Stated under AIR
and HEAT, respecting the extreme compressibility
of airs or gases; all of which must (in the state in
which we examine them) be considered as compressed
enormously, by the superineumbent weight of the
atmospheric ocean. Any portion of air then enclosed
in a vessel, exerts a great pressure, by tending to
expand, and therefore to burst the vessel, were it not
for the external pressure, which exactly counteracts
this tendency. If, however, the temperature of the
vessel be raised above that of the external air, al-
though the included air cannot expand, yet the repul-
sive force between its particles will be increased; that
is to say, its pressure or elaszfz'ez'z‘g/ will be increased,
and by exceeding that of the external air, may lead to
the bursting of the vessel, as when an inflated bladder
is held near a fire. The bulbs of the differential ther—
mometer, however, are made strong enough to resist
a moderate inequality between the internal and ex-
ternal pressures; but if, by a difference between the
temperatures of the two bulbs, the expansive force of
the air in one of them should exceed that in the
other, the column of liquid in the tube will imme-
diately move towards the colder bulb, till by com-
pressing the air in that bulb, and allowing more room
for the air in the warmer bulb, it has equalized their
elasticity or pressure. It will therefore sink in the
stem of the warmer bulb, and rise in the other stem,
and the amount of this rise is measured by a scale s.
In order to render this scale as efiicient as possible,

the quantities of air in the two bulbs are so adjusted,
that when both have the same temperature, the liquid
may stand near the top of the stem of A, but near the
bottom of the stem of :B, to which the scale is at—
tached, with its zero opposite the liquid surface. This
instrument therefore always indicates 0° when there
is no deference between the temperatures of the two
bulbs; its chief value, in fact, depending on its total
indifference to all changes that affect both bulbs alike.
The scale therefore indicates only the dg'fi'erenee of the
temperatures of the two bulbs (whence the name of
the instrument). This scale is usually divided in
such a way that 10 of its degrees correspond to 1° of
the French Centigrade scale, so that a rise of 10 of
these degrees denotes the bulb A to be 1° Centigrade
warmer than B. Of course the bulb A must always be
exposed to the higher temperature, otherwise the
liquid would retreat out of the range of the scale——
hence A is generally called the sentient bulb.
It was by means of this instrument, combined with
a mirror for condensing the heating rays upon the
sentient bulb, that Leslie made those remarkable dis-
coveries respecting radiant heat which have been
briefly noticed under HEAT ; and in order to keep the
scale bulb out of the course of the rays, it was
generally made to stand lower than the sentient
bulb, although both are shown of equal height in the
figure,—--the scale bulb being there supposed to be on
one side of the focus, which is concentrated on the
other bulb.
M. Melloni, in pursuing the investigations on
radiant heat, found it necessary to have a differential
instrument for measuring very minute changes in
temperature, of which the instruments before de-
scribed are altogether incapable. It is obvious, that
there is a large number of temperatures within the
range of only one degree on Fahrenheit’s, or even
Leslie’s scale; and analogy would lead us to suppose
that there are many states of matter, inorganic as well
as organic, which, if they do not absolutely depend
upon such small changes in temperature, at least owe
many of their modifications thereto. Our knowledge
of animate nature must obviously progress only in
proportion to the progression of our instrumental
aids. The chrysalis of a butterfly, and the insect
itself, have been proved to possess temperatures
essentially different; and yet this difference is but a
fraction of a degree on Fahrenheit’s scale. The
means for determining so simple a fact as this must be
invaluable to the natural historian; and such means
we will briefly indicate.
The Therm-Multiplier is an instrument contrived
by Nobili and Melloni, for measuring small quantities
of radiant heat, by means of the electric currents
which are excited when metallic bodies are unequally
heated. These t/zermo-eleezfrz'e currents (as they are
called) are always extremely feeble, even when the
difference of temperature between dilferent parts of
the metal is considerable, and they are feebler in pro-
portion as that difierence is less; but there is hardly
, any limit to the delicacy with which we may detect
electric currents by their magnetic ,effects. The
aurnnirorrnrrur **
846
effect of such currents in disturbing the position of
a magnetic needle [see Etncrnrc TELEGRAPH] is'
multiplied by making the current pass many times in
the same direction; thus when the conducting wire
is coiled into a spiral form or lielz'zr, each turn adds to
the effect on the needle. On this principle is con-
structed the instrument called the galvanometer, the
delicacy of which depends on the number of turns in
its wire, and may therefore be increased almost without
limit. . .
Mclloni’s heat detector consists of a galvanometer,
9 Fig. 2171, so arranged as to receive and measure the




Fig. 2m.
electric current excited in a thermo-electric pile or
battery a‘. This battery is constructed on the principle
that in some metals, when unequally warmed, an elec-
tric current flows from the hotter to the colder part ;
while in other metals the reverse is the case. The
former kind of current is excited most powerfully in
bismuth, while the latter property exists most de-
cidedly in antimony. The pile or battery, therefore,
consists of 36 small slips or bars of antimony, and
the same number of bismuth, all packed together and
enclosed in a ring, so as to form a bundle or faggot,
little more than an inch long. The two faces of this
bundle are made flat, and the bars so soldered toge-
ther, two and two, at their ends, as to form one
unbroken connexion from the first bar to the last, from
which two bars the wires proceed to the galvanometer.
The bars are kept from touching, except at their ends,
by some non—conductor of electricity, (as silk or resin,)
and the ring is also made of non-conducting material.
The two ends or faces of the bundle are covered with
lamp-black, that they may freely both receive and
emit radiant heat; and whenever the temperature
of either of these faces is raised above or cooled
below that of the other, an electric current flows
through each antimony bar, from the cooler to the
warmer end, and through each bismuth bar in the
contrary direction, so that all these currents combine
to form one general flow, setting from the galvano-
_ meter through the first antimony bar, back through
the second bar (of bismuth), forward through the
next bar (of antimony), and so on alternately to the
last bar, from whence it returns to the galvanometer.
The advantage of this contrivance is, that degrees of
heat so small as to be quite inappreciable by the most
delicately constructed thermometers, are multiplied,
as it were, by the multiplication of the number of
pairs of metal bars, and again by the turns of the
spiral wire, and thus produce a sensible effect on the
galvanometer-needle.
By means of a joint, properly situated, the axis of
the pile can be placed at various inclinations, so as to
point towards the object whence the rays that are to
be observed proceed 5 and, in order to exclude all the

rays that may come from other objects, the pile is
enclosed in tubes of metal, which are blackened within,
and polished without so as to reflect away the oblique
rays.
By the aid of the thermo-multiplier, many important
,results have been obtained in the examination of
organic and inorganic nature; as also in the cousin
deration of various problems connected with geology,
physiology, and natural history. The instrument is
said to have detected the rays proceeding from a
warm hand, at the distance of thirty feet.
We will give a few examples of the application of
this instrument, illustrative of the action of heating
rays upon certain substances. Let the source of heat
be the flame f, Fig. 2171, and let the heating rays
pass through the perforation in a screen 8, and fall
upon the substance under examination, which is
mounted on a stand .9‘. The thermo-electric pile i
will cause the galvanometer g to indicate the action
of the calorific rays on the substance on the stand.
In this way Melloni found that heat which has passed
through one plate of glass is less susceptible of
absorption in passing through a second plate. Of
1,000 rays of heat from the oil lamp /, 451 were in-
tercepted in passing through 4t equal plates of glass,
of which 381 were intercepted by the first plate, 43
by the second, 18 by the third, and 9 by the fourth.
It was also found that radiant heat will pass freely
through certain transparent bodies, while other bodies
apparently of equal transparency resist its passage.
Bodies which transmit rays of light are called trans-
parent, or chap/muons; those which transmit rays of
heat are termed diaflzermanous ; but it does not
follow that those bodies which transmit luminous rays
also transmit heating rays. Rays from different
sources of heat appear to have different properties;
or, in other words, as there are varieties of light, dis-
tinguished by different colours and refractive powers,
so there are different kinds of radiant heat varying
with the source from which it emanates. The follow-
ing table states the number of rays transmitted by
certain substances when the source of heat was, first
an oil flame, secondly red hot platinum, thirdly
copper heated to 7 32°, and fazm‘kly a thin copper
vessel blackened on the outside and filled with boiling
water :-—-—

Transmission of 100 Rays of
fr

Beat om
Substances interposed of the common 3
thickness 0'102 inch. g ,3 .= i E ‘5
.2 8 --L- 3 2'2; 2:,-
ss as a» as
F__ ,3 x~ o:
43 a2 a? 48
Rock-salt, transparent and colourless 2 92 92
Fluor spar, ditto ditto 69 42 33
Rock-salt, clouded ....................... .. 65 65 65
QC

Beryl Fluor spar, greenish and transparent
WM
WOO
NH
“LCD
N
Iceland spar . 28
Plate-glass .-
Rock’crystal, colourless 28
ditto brownish Tourmaline, dark green......
Citric acid, colourless ................... ..
Alum ditto .
Sugar candy ditto Fluor spar, green, translucent ....... ..
_Pure ice, colourless and transparent
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1844
THORIUM—TIN.
Rock-salt possesses remarkable properties with
‘respect to radiant heat; it is the only substance that
transmits equally the rays from different sources, and
it does so in the large proportion of 92 per cent.
Sulphate of copper, on the contrary, which allows
light to pass, is at/termarzous or opaque with respect
to heat. Rock-salt has been called the“ true glass
of radiant heat ;” it may be cut into lenses and prisms,
and used for concentrating heat, or decomposing it by
double refraction. '
Of 100 rays of heat from the same source it was
found that water transmitted 11, alcohol 15, ether 21,
bisulphuret of carbon 63, and chloride of sulphur 63.
When equal plates of coloured glass were employed
it was found that violet glass transmitted 53 per cent,
red 47, yellow 34:, blue 33, and green 26. Rays of
light which have passed through blue glass will pass
more readily through a second blue glass than through
one of a different colour: and rays of heat which have
passed through water will pass more readily through a
second stratum of water than through other liquids,
which in the first instance are more diathermanous
than water. Hence it follows that but little addi-
tional heat is absorbed when the number or thickness
of screens of the same material is increased.
We may appropriately conclude this article, on one
of the most important instruments that has ever
assisted the progress of knowledge and of the useful
arts, with the remark of a great German philosopher,
“ Das Instrument macht ja das Werk nicht, sondern
der menschliche Geist.” It is not to the instrument
that we are indebted for great discoveries, but to the
genius of man, who slowly but surely gropes his way
from the known into the unknown, and uses the in-
strument as a small means to a great end.
THIMBLE. See RAISED Wonxs IN METAL.
THORIUM, Th60, the metal of an earth from a
rare mineral, flzorz'te ,- it agrees in character with
aluminium. The oxide T/zorz'mz, ThO, has some re-
markable chemical properties.
THREAD. See COTTON—FLAX—SILK.
THREADS OE SCREWS. See Scnnw.
TIDE-MILL. See introductory remarks
STEAM—ENGINE.
TILES AND PAVEMENTS. See POTTERY AND
PORCELAIN, Sect. VL—Bohns.
TILTING. See IRON, Sect. VII.
TIMBER. See WOODS.
TIMBER BRIDGES. See BRIDGE, Sect. IV.
TIN. Sn59. Tin is one of the ancient metals. It
was known in the time of Moses, and was procured
at an early period from Spain and Britain by the
Phoenicians. It occurs abundantly in Cornwall, and
is also found in Germany, Bohemia, and Hungary ; in
Chili and Mexico; in the peninsula of Malacca, and
in the island of Banca. In Cornwall the tin-stone is
found in veins, associated with copper ore, in granite,
and slate rocks, in which case it is called mine-tin:
it is also met with as an alluvial deposit mixed with
rounded pebbles, in which case it is called stream-Zia.
Oxide of tin is also found disseminated through the
rock in small crystals. The principal ore of tin is the
to
native peroxide. The preparation of the ores for
vreduction is described under METALLURGY. The
method of smelting will be noticed presently.
Tin is a white metal, approaching silver in lustre,
but when viewed so as to exclude the white light
reflected from its surface, it has a yellow tint. It has
a peculiar taste, and when rubbed, or held in a warm
hand, it exhales a peculiar odour. Tin is very mal-
leable ; it may be beaten out into thin sheets. Com-
mon tin-foil is often not more than 1010 0th of an inch
in thickness, and what is termed w/zz'tc Data/z metal is
much thinner. The malleability of tin is increased
by raising its temperature to 212°. Tin is not very
ductile : when bent or twisted it emits a creaking or
crackling sound, (called by the French, are‘ dc Z’éz‘az'rz,
or tin-021%) in consequence of the crystalline texture
of the interior, the noise being occasioned by the fric—
tion of the crystals on each other: in this operation
the temperature rises, and, if continued, the heat is
very sensible to the hand. The tin-cry is prevented
by the addition of a very small portion of lead. Tin
fuses at 442° Fahr., and contracts slightly on conso-
lidation. When strongly heated it gives off while
fumes. Its density varies from 7'29 to '7 '6, the light-
est being thepurest metal. Its specific heat is 005623.
Tin has a strong tendency to crystallization, as may
be seen by applying an acid to its surface to remove
the exterior pellicle. The surface then becomes
mottled in consequence of the irregular reflection of
the fern-like crystals brought out by the action of the
acid. .Moz'r'e’e memllz'gae is thus produced. Tin-plate,
with a somewhat thick coating of pure tin, is best
adapted to this manufacture. It is well cleaned by
washing its surface in caustic potash, rinsing, and
drying. The acid employed is a mixture of nitric and
hydrochloric in water; 2 of nitric, 3 of hydrochloric,
and 8 of water, answer very well. The plate is to be
slightly heated, and then quickly sponged over with
the acid so as to bring out the moirée. It is then to
be dipped in water, washed, and dried. If the surface
has been blackened or oxidized by the acid, it may be
cleaned by a solution of caustic potash. The crystals
on the unprepared tin plate are usually large and in-
distinct; but by heating the plate up to the point of
fusion of the tin, powdering it over with sal-ammoniae
to remove the oxide, and plunging it into cold water,
the crystals may be had small. Various modifications
of the crystalline surface may be obtained by sprink-
ling the surface of the heated plate with water, or by
holding the plate over the flame of a spirit-lamp so as
only partially to fuse the tin: or by running a blow-
pipe flame over it. The plates are finished with a
coating of transparent and slightly coloured varnish.
Tin may also be crystallized by fusion, as in the case
of BISMUTH, but the crystals seldom have sharp well—
defined edges. Tin may also be deposited from its
solutions by electric agency, in elongated brilliant
prisms. The tin of commerce is never quite pure: it
contains arsenic and other bodies, and it is said to be
purposely adulterated with iron or lead. Pure tin is
sometimes judged of by its cry/.- when impure, the

sound is short, and interrupted; but when pure it is
TIN.
845
a connected creaking sound, somewhat like that pro-
duced by sole-leather. To obtain it pure, tin filings
or granulated tin must be treated with an excess of
nitric acid, and the resulting slamzz'c acz'cl washed with
hydrochloric acid, and then with water. The peroxide
of tin thus obtained is reduced to the metallic state
in a closed crucible lined with charcoal, and raised to
a low white heat. Tin is not much affected by ex-
posure to the air at ordinary temperatures, but when
fused its surface becomes covered with a greyish
pellicle, consisting of protoxide of the metal with
stannic acid. If the temperature be raised to a white
heat, tin burns vividly, and if a globule of the metal
be thrown upon a sheet of dark-coloured paper, it
divides into small particles u hich burn vividly, and
leave lines of white oxide. At a red heat tin decom—
poses vapour of water, peroxide being formed, and
hydrogen gas evolved. Water is also decomposed by tin
in the presence of the fixed alkalies, and on heating it
in a concentrated solution of potash or of soda, hy-
drogen is evolved, and a stannate of the base formed.
Strong hydrochloric acid dissolves tin with the
production of hydrogen. Warm dilute sulphuric acid
produces similar effects, but very slowly. Concen~
trated sulphuric acid acts on tin with energy, sulphate
of the protoxide being formed, and sulphurous acid
evolved. Nitric acid acts upon tin with great energy,
as already noticed, stannic acid being formed, and
nitric oxide evolved largely. But if the acid be very
dilute, the gas is not given off, but peroxide of tin
and nitrate of ammonia are produced.
Proloa'z'rle of tin, or slannozls oa'z'cle, SnO, is obtained
by precipitating a solution of protochloride of tin by
means of ammonia: the precipitate is a hydrate;
when dried out of contact with air it is of a dark
colour, and is not decomposed by heat alone. It may
be rendered anhydrous by heating the hydrate to red-
ness in a retort filled with carbonic acid. It forms a
dense black powder, which takes fire on the approach
of a red-hot body, and burns like tinder, producing
peroxide. There is also a sesquioxide, 8n203. The
peroxide, also called szfmzm'c acz'cl, 81102, is procured
in two different states which have dissimilar properties.
When perchloride of tin is precipitated by an alkali,
a white bulky hydrate is formed, which is soluble in
acids. But if the bichloride be boiled with excess of
nitric acid, or if nitric acid be made to act on metallic
tin, awhite substance is formed, not soluble in acids,
and differing in other respects from that formed by
the other process. They have, however, the same
composition, and, when ignited, form a pure peroxide
of a pale yellow tint: they both dissolve in caustic
alkali, and are precipitated by an acid. When per-
oxide of tin is fused with glass, it forms white enamel.
[See ENAMEL] Tie putty, or jewellers’ pally, [see
Purcrverownnnj is probably a mixture of the pro—
toxide and peroxide of tin.
The proloclilom'cle cf #12, SnCl, is formed by dis-
solving metallic tin in hot hydrochloric acid. It
crystallizes in needles containing 3 equivalents of
water. The chloride may be obtained anhydrous by
distilling a mixture of protochloride of mercury and

powdered tin. Chloride. of tin is a grey resinous
looking body, fusible below a red heat.
in a small quantity of water, but is decomposed in
a large quantity, unless an excess of hydrochloric
acid be present. “ This acid solution quickly absorbs
oxygen, and if added to certain metallic solutions
revives or deoxidizes them. It decomposes and pre-
cipitates sulphur from sulphurous acid. It reduces
the persalts of iron to protosalts, and converts arse-
nic acid into arsenious, and chromic acid into oxide of
chromium. With a very weak solution of corrosive
sublimate it forms a grey precipitate of metallic mer-
cury. Added to a dilute solution of chloride of pla-
tinum, it changes its colour to a deep blood-red. With
solution of gold, it produces a purple precipitate used
in painting porcelain, and known under the name of
Purple of’ Cassius. With infusion of cochineal, it pro-
duces a purple precipitate; and it is much used to
fix and change colours in the art of dyeing and calico-
printing. The greater number of vegetable infusions
are precipitated by it, in consequence of the insoluble
compounds which it forms with the varieties of ex-
tractive matter.” ‘
Perclzlom'cle or biclzlom'cle of live, SnCl‘l, formerly
called “fuming liquor of Libavius,” may be formed
by exposing metallic tin to the action of chlorine, or
by distilling a mixture of 1 part tin in powder, and 5
parts of corrosive sublimate. It forms a thin, colour-
less, mobile liquid, which boils at 248°: it fumes in
the air, and when mixed with one-third part of water
forms a solid crystalline mass. The dyers use the
solution as a mordantjand prepare it by digesting tin
filings in single aquafortis, adding 2 oz. of common
salt or sal-ammoniac to every pound of the solution.
When tin is fused with excess of sulphur and the
product strongly heated, prolosulplmrcl, 8118, is
formed; it is a lead-grey, brittle substance. By
heating this with one-third of its weight of sulphur,
a sesgzlz'sulplmrel Sn2Ss, is formed: it has a yellowish-
grey colour, and a metallic lustre, and is readily
decomposed by heat. Bisulplmrel of 25292, Snsz, is
prepared by exposing to a low red heat, in a glass
flask, a mixture of 12 parts tin, 6 mercury, 6 sal-
ammoniac, and 7 flowers of sulphur. Sal-ammoniae,
cinnabar, and protochloride of tin sublime, and the
bisulphuret is left at the bottom of the vessel in the
form of brilliant gold-coloured scales, called am'um
masz'cum or mosaic gold. It is much used for orna~
mental work under the name of broizzejoowrler [see
Bnonzme], especially by the manufacturers of paper
hangings. It is principally imported from Holland
and Germany.
The other salts of tin do not require special notice,
except that variety of the suljilmz‘e which is known as
Bancrofl’s lz'n _momlrmt. It is prepared by pouring 3
parts of muriatic acid on 2 of tin filings, and after the
lapse of an hour adding carefully 1'5 parts of sulphuric
acid : the tin dissolves, and the mixture is kept warm
so long as hydrogen is evolved : when cold the residue
is dissolved in water, poured off from the undissolved

(1) Brande: “ Manual of Chemistry, 1848.”
It is soluble '
846
TIN.
tin, and diluted so that 8 parts of the solution may
contain 1 part of tin.
The tin of commerce is obtained from the native
oxide, which in its pure state consists of Sn Oz. A
specimen from Cornwall, analysed by Klaproth, gave
tin 7 7 '50 per cent., oxygen 21'50, oxide of iron 0'25,
silica 0'7 5. The most common crystals are square-
based prisms terminated by 4! triangular faces, often
modified on their edges and angles. The massive
varieties of oxide of tin are called stream—tin. When
the ore occurs in reniform masses, or wedgeshaped
pieces with concentric bands, which give a ligneous
appearance to the mineral, it is called wood-tire.
Stream-tin is probably derived from the destruction
of tin veins or lodes; the lighter portions having
been carried away by the water which rounded the
fragments of the ore. See MINE—MINING, Fig.
15412.
Tin pyrites or sulphuret of tin is a scarce mineral ;
it has been found in Cornwall in a crystalline state
in one locality only,-—Huel Rock Mine, St. Agnes.
When the ores have been washed and prepared as
described under METALLURGY, they are roasted to
get rid of sulphur and arsenic. Reverberatory
furnaces are used for the purpose, the fines of which
are connected with large condensing chambers, in
which the arsenic is deposited in a crystalline form.
By a second sublimation it forms the white arsenic of
commerce. [See Ansnnre] When the ore ceases
to exhale white fumes, it is let down into an arched
chamber below the furnace to cool. The calcined
ore is again washed, and the impurities, which have
for the most part been decomposed and converted
into peroxide of iron, are removed. If the ore con-
tains copper pyrites, it is after a careful roasting
exposed for some time to the atmosphere before being
again washed, in order partially to oxidise the sul-
phurets, and convert them into sulphates, which are
soluble in water and thus more easily removed. If
the tin ores contain copper, they may after roasting
be treated with dilute sulphuric acid, which dissolves
the copper but does not attack the tin. After wash-
ing, the ore is called Mae/e tin, and is ready for
smelting. The method of treating tin ores which
contain Wolfram is noticed ins our INTRODUCTORY
EssAY, page xcvi.
The smelting of tin ores may be conducted either
in a reverberatory furnace with common pit coal, the
ore being mixed with powdered anthracite or other
carbonaceous substance; or, where a very pure metal
is required, in a small blast furnace with charcoal for
fuel. The former process is conducted in what are
called smelting houses, and the latter in blowing-
izouses.
The reverberatory furnace is shown in vertical
section Fig. 2172, and in plan Fig. 217 3. Coal is sup-
plied to the grateg, by the fire-doorf; the ore is intro-
duced to the hearth it by the hole 20. d is the working
door, and at a is a hole occasionally opened for the
purpose of admitting a draught of air for carrying the
fumes up the chimney during the skimming of the
slags; at e is a channel for admitting air beneath the

hearth and through the fire-bridge for moderating
the heat; 6 is a basin into which the metal is drawn
off; 0 is the chimney, which should be 110 or 50 feet
high. The ore is well mixed with about s-th of its
weight of powdered coal or anthracite, and a small
quantity of slaked lime or fluor spar, to serve as a





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Figs. 2172, 2173.
SECTIONAI' ELEVATION AND PLAN OF TIN
SMELTING- FURNACE.
flux for the silica present. The charge consists of
20 to 25 cwt. of ore, and contains from 60 to 65 per
cent. of metal. It is slightly sprinkled with water,
to make it more compact, and prevent any of it from
being carried off by the draught. During the first 6
or 8 hours the furnace doors are kept closed, and the
heat is gradually raised. The oxide being then
reduced, the door d is opened, and the fused mass is
worked with a long iron paddle to separate the metal
from the slags, which being done, they are carefully
withdrawn by an iron rake, and are afterwards divided
into 3 classes,~—-1. Those of the first class, which
form about a of the whole weight produced, contain
little or no metal, and are rejected. 2. Those of the
second class contain small globules of tin to the
extent of about 5 per cent., which are separated by
washing at the stamping-mill. 3. The slags of the
third class, small in quantity but rich in metal, are
those scoriee which are removed by the rake just
before the metal is let out into the basin 6 .- they are
set aside for mixing with the next charge. The clay
stopple is removed by a pointed iron bar from the
channel which leads into the basin 5, and the metal
flows out, and being left for a short time any remain-
ing slags rise to the surface and are skimmed off.
TIN.
87177
The tin is then ladled into rectangular moulds, from
which it comes out in the form of blocks.
The tin thus produced is contaminated with iron,
arsenic, copper, and tungsten, and also contains some
oxide of tin not reduced. It is refined by two pro-
cesses, the first of which is a ligualz'on in a reverbera-
tory furnace similar to Fig. 2172. The second is a
species of policy, somewhat similar in effect to the
operation described under Oorrnn. For the liquation,
the impure blocks of tin are arranged in a sort of
hollow heap near the fire-bridge, and gradually heated
to the fusing point. The tin flows for some time into
the outer basin, and a ferruginous dross remains in
the furnace. Other blocks are put into the furnace,
and the operation is continued for about an hour,
until about 5 tons of metal are collected in the basin.
The ferruginous residue is removed, and is afterwards
treated with the slags of the second and third class of
the smelting, and being all smelted together, produce
tin of very inferior quality. The second part of the
refining process consists in lowering into the bath of
liquid metal, by means of an iron gibbet, billets of
green wood, which by their rapid evolution of gas
produce the appearance of boiling in the metal, and
the effect is to bring to the surface a kind of froth,
consisting of oxide of tin and other oxides, while the
more impure and denser portions of the foreign sub-
stances subside. The froth is skimmed off and
returned to the furnace, and when the operation has
been continued for about 3 hours, the wood is removed
and the contents of the basin left to subside. In the
course of about an hour the metal forms 3 strata, of
which the top stratum is most pure, the bottom
most impure, and the middle of average purity. The
three layers are ladled out into iron moulds, forming
blocks, each weighing about 3 cwt., and being what
is called bloc/r lie. The tin of the first stratum, or
a-gined lie, is chiefly employed in the manufacture of
tin-plate. The blocks from the third or bottom
stratum are often so impure as to require a second
refining in the reverberatory furnace.
In some cases, instead of refining by means of green
wood, the operation of tossing is substituted. The
men take up portions of the metal in ladles, and allow
them to fall into the refining pet from a considerable
height. The agitation thus occasioned produces a
somewhat similar effect to the green wood.
Grain-tin is prepared by plunging blocks of tin in
a bath of tin, and when it has assumed a brittle
crystalline texture, it is broken up with a hammer;
or the blocks are heated nearly to the point of fusion,
and then allowed to fall from a considerable height;
the metal thus breaks up into elongated grains, called
by the French c'laz'n e22 lar/res, or tears of tin; the
operation may in fact be regarded as a kind of refin-
ing of fine metal.
The blast furnace is not used in this country for
smelting tin ores; for although it affords a pure metal,
it is more costly than the reverberatory furnace. In
the latter 1%,, ton of coal is consumed for every ten
of tin produced, and the loss of metal is about 5 per
cent. With the blast furnace 1 'f65'tl13 ton is required

for every ten of tin, and the loss is about 15 per cent.
In those mining countries, however, where coal is
scarce and wood tolerably abundant, the blast furnace
is used. Fig. 217 4e represents in elevation and plan
the furnace used in the Erzgebirge of Saxony. The


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.Fz'g. 2174. ELEVATION AND PLAN on rm BLAST FURNACE-
sides of the trunk 17‘ are of granite; the sole is also a
block of granite shaped so as to have a considerable
fall towards the breast of the furnace. The fused
mass resulting from the reduction of the ore flows
into a granite basin 6, which is lined with a mixture
of clay and charcoal; this basin communicates by a
tapping hole with an iron vessel 2'. The charcoal and
the ore are introduced into 25, in charges, at stated
intervals, and the combustion is urged by a blowing
machine, the nozzle of which is introduced at 0. The
slags float on the surface of the metal in Z), and are
removed from time to time by an iron crook. When
6 is full, its contents are let out into 2', and a large
pole of green wood is introduced for the purpose of
refining; the metal on being left to itself separates
into layers of different degrees of purity. There are
two classes of slags ; the richer are added to the
succeeding charge, and the poorer are stamped and
washed for the purpose of separating the metallic
particles entangled in them.
In the year ending 5th January, 1852, the quantity
of tin imported into the United Kingdom in the form
of blocks, ingots, bars and slabs amounted to 418,746
cwt., of which 37,727 cwt. were entered for home
consumption. The gross duty received amounted to
11,331l.
Tin forms with some other metals alloys distin-
guished by whiteness, hardness and fusibility. See
PnwrEn—Bnonzn—BnAss—Sommn.
One of the most important of the tin alloys is that
with iron in the form of tin plate, which unites the
useful qualities of both metals. Other forms of iron
are also coated with tin, to preserve the iron from
rusting and staining other substances in contact with
it. Many articles, such as bridle-bits, common stirrups,
small nails, &c. are manufactured more cheaply than
formerly, by making them of east-iron and then tinning
them. Saucepans and large pots of cast-iron are also
tinned on their inner surface, which must ‘be made
chemically clean for the purpose; then heated and
grain tin being poured in, the vessel is to be
rolled about and the surface rubbed with cloth or
tow: powdered resin is also used to prevent the
formation of oxide. Vessels of copper and brass as
well as cast-iron are tinned in this way. But for
many of the purposes for which tin was formerly em-
ployed, zinc is now used. [See ZINC ; and for one
848
TIN.
method of galvanising iron, see AMALGAMJ For tin-
plate or wiiz'ie area, however, the demand for tin is as
large as ever. Tin—plate consists of thin sheet-iron,
covered on both sides with an equable layer of tin,
and worked up by the tin-man or tin-plate worker
into numerous articles of culinary or domestic use.
The iron used for the purpose is charcoal iron, and
is rolled out to various degrees of thinness, and
cut by shears into rectangles of different sizes. The
sheets are arranged in homes, or heaps, of 225 in
each 50.1.21
In order that the tin may perfectly adhere to the
iron, the surface of the latter must be chemically
clean, and the melted tin be protected from the
oxidising influence of the air. A man, called the scalar,
bends each iron plate so as to enable it to stand on
edge, and then places it in a trough containing a
pickle of dilute muriatic acid. In 41 or 5 minutes the
plates are taken out, placed on the floor in a row, and
an iron rod being under them, they are lifted up and
conveyed to a furnace where they are heated to red-
ness. This causes the oxide to scale off, and when
taken out and cold, they are beaten straight and
smooth on a cast-iron block. If the plates have been
properly scaled they have a mottled blue and white
appearance, something like that of marbled paper.
The plates are further smoothed by being passed be-
tween a pair of hard polished rollers. This cold-
rolling gives them great smoothness and elasticity.
The plates are next immersed in an acid mixture
of bran and water, one at a time, to insure a complete
wetting: they are left standing on their edges for
about 6 hours ; then turned upon the opposite edge,
and left for another 6 hours. They are then trans-
ferred to a pickle of dilute sulphuric acid, contained
in a leaden cistern, divided by partitions into spaces,
each of which, called a izole, contains a box of plates.
The acid removes black spots, and makes the plates
bright; but the pickling must not be carried too far,
or the plates will become stained or blistered. Both
this, and the former process with bran-water, are
assisted by a gentle heat of 90° or 100°, for which
purpose the troughs are placed over heated flucs.
The plates are transferred to clean water, and secured
with hemp and sand, after which they may be kept
immersed in water during many months without rust-
ing or losing their bright appearance.
About 5 cwt. of block and grain-tin, in nearly equal
proportions, are melted in a cast-iron vessel, No. 1,
Fig. 2175, and called the tin-pot. It is heated by a
fire beneath, with the flue passing quite round the
vessel. A quantity of tallow is added to the tin, sulfi-
cient to cover the surface to the depth of 43 inches, in
order to prevent contact with the air. Another pot,
by the side of the tin-pot, is filled with grease only,
and into it the prepared plates are put previous to

( 1) The chief authority for the details of the manufacture of
tin—plate is a description by Mr. Parkes, published in 1818, in
“ The Memoirs of the Literary and Philosophical Society of
Manchester,” derived from personal inspection. The manufac-
turers, however, affect a good deal of mystery on the subject,
and the editor has never had an opportunity of witnessing the
processes; but they are sufiicient'ly intelligible from description.

tinning. They are taken out one by one, and plunged
into the tin in a vertical position to the number of
200 or 300, and are left an hour or two in the tin,
E515
Fig. 2175.
which is kept as hot as possible without firing the
grease. The plates are then taken out with tongs,
and placed upon an iron rack or grating, where a con-
siderable portion of tin drains off, but a still larger
quantity is removed by the process of was/ring. The
waslzmcm prepares an iron pot, No. 2, Fig. 2175
nearly full of the best grain-tin melted, and called the
wash-pot; this pot is divided by a partition to pre-
vent the dross from lodging in that part of the vessel
where the last dip is given to the plates. Next to
this is another pot, No. 3, called the grease-pot‘; it con-
tains clean melted tallow or lard free from salt. No. 4',
called the pan, is a pot containing only a grating at
the bottom; it is for the reception of the plate when
taken out of the grease-pot; this pet has no fire under
it. No. 5 is called the list-1902.‘; it contains only a
small quantity of melted tin, sufficient to cover the
bottom to the depth of 4i inch. The building con-
taining these pets is called the stow, and the plates
are worked from the right-hand to the left. The
asterisks show where the work—people stand.
The wash-man commences operations by putting
the plates already tinned in No. 1, into the wash-pot
No. 2, and the heat of the large body of tin contained
in it soon melts all the loose tin on the surface of the
plates, and this gradually deteriorates the quality of
the whole mass, so that after 60 or 70 boxes have
been washed in the grain-tin, it is usual to transfer a
quantity to the tin-pot, No.1, and replenish the wash-
pot with a fresh block of gFain-tin. The vessels hold
3 blocks each, or about half a ton weight of metal.
The plates are taken out of the wash-pot, a few at
a time, and placed on the stow. The wash-man then
takes up one plate with a pair of tongs held in his
left-hand, and, with a kind of hempen brush, sweeps
one side of the plate, turns it and sweeps the other
side, dips it into the hot fluid metal of the wash-pot,
for the purpose of removing the marks of the brush,
and then into the grease-pot, No. 3. A good work-
man will brush and tin-wash 25 boxes, or 5,625 plates,
in 12 hours. The use of the grease-pot is to remove
the superfluous metal from the plates; but this re-
quires care, because, as the tin is in a soft state when
immersed in the grease, too much or too little may be
removed: if too much, the plates lose their silvery
lustre; if too little, the tin is wasted, and the plates

2.
-___J
*6 a

TINUI‘URE—TITANIUM-TOBACOO.
*WSE
are disfigured by streaks. The temperature of the
grease-pot requires regulation, because, as a thick
plate retains more heat than a thin one, it requires a
proportionally cooler grease-pot. The grease-pot
has pins fixed within it, to keep the plates asunder,
and whenever the workman has transferred 5 plates
to it, a boy lifts the first plate out into the cold pan,
No. 4:, and as soon as the man transfers a sixth plate,
the boy removes the second, and so on. The plates
are left in No. 4: until they become cold enough to
handle. As the plates are placed vertically in the
melted tin, and also in the grease-poththere is a list
or selvage of tin on the lower edge of each plate after
it becomes cold : this is removed by dipping the lower
edge of each plate into the list-pot, No.5, which
contains melted tin to the depth of about 7},— inch.
When the list is melted, the boy takes out the plate
and gives it a smart blow with a thin stick; this de-
taches the superfluous metal, and leaves a faint mark
in its place, which may be noticed on every tin plate.
The plates are cleansed from grease by being put,
while warm, into bins of dry bran, with which they
are rubbed until they become quite clean. They are
then packed up in boxes, each containing a certain
number of plates, according to their quality, which is
distinguished by certain marks attached to the boxes,
as shown in the following table :—




No. in lWeigl'it of Marks on
Names- s‘zes' a box. I each box. the boxes.
Inches. cwLqrJb.
Common No. 13% by 10 225 1 0 0 CI
Common No. 1% by 9i 3 21 CH
Common No. 12§ by S)2 3 16 CHI
Cross No. 1. 13% by 10 1 1 0 X1
Two Cross No. 1. 1 l 21 XXL
Three Cross No. 1. 1 2 14 XXXI
Four Cross No. l ....... .. l 3 7 XXXXI
Common Doubles ...... .. 16% by 12% 100 2 21 u E CD
Cross Doubles ........... .. l 0 14 XD
Two Cross Doubles 1 1 7 XXD
Three Cross Doubles... 1 2 0 XXXD
Four Cross Doubles..... 1 2 21 XXXXD
Common Small Doubles 15 by 11 200 1 2 0 ( SD
Cross Small Doubles l 2 21 XSD
Two Cross Doubles .... .. l 3 l4 XXSD
Three Cross Doubles... 2 0 7 XXXSI)
Four Cross Doubles,.... 2 1 0 XXXXSD
Wasters,Common,No.l. 13?’ by 10 ,225 1 0 0 WCI
Wasters, Cross, No. 1.. 13;, by 10 1 1 0 WXI
TINCAL, an impure borate of soda. See BonAx.
TINCTURE, a solution of the active principle of
a substance, generally vegetable, sometimes saline or
animal. Being always more or less coloured, it has
obtained its name from iincins. A tincture is simple
when only one substance is submitted to the action
of the solvent, and compound when two or more are
concerned. When alcohol is the solvent employed
the tincture is said to be alcoholic; ei/ierenl when
sulphuric ether is used; when wine is employed the
result is called nzerlicalccl wine, and when distillation
is made to assist the extraction the result is called a
spirit’. When ammonia is used in conjunction with
alcohol, an nmmoniai‘ecl zfinclnre is produced. Tinctures
were formerly called essences, from ease, to be, on the
supposition that the solvent took up only the purer
and essential principle of the substance, rejecting the
starch, gum, ligneous fibre, 8:0. The term qziinies-
sence was only a higher and purer form of essence.
VOL. II.

An elixir had greater consistence than an essence, and
was often turbid from the suspension of extractive
matter. The advance of pharmacy on the principles
of scientific chemistry has discarded these latter terms,
and the fancies which originated them.
In alcoholic tinctures the strength of the spirit
employed varies with the nature of the substance to
be acted on. A resinous body requires a strong or
proof, or above proof spirit; a gummy substance a
more dilute or nneler proof spirit. A tincture should
be clear, and its colour characteristic of the base or
active principle of the substance, and having also its
taste and odour. In preparing a tincture the sub-
stance is to be bruised, and 5 or 6 parts of spirit
added. The maceration should be conducted in well
stoppled glass vessels for about 14¢ days with frequent
shaking. At the end of this time the tincture is to
be strained or filtered, and preserved in well stoppled
dark glass vessels, not exposed to the light. Many
tinctures deposit a sediment, become turbid, and
undergo certain changes which interfere with their
being kept. This may be prevented by first forming
vegetable juices by expression of the fresh plant,
allowing the feculent matter to subside by repose and
the addition of alcohol 56° over proof, filtering and
preserving in glass bottles as before. Tinctures are
often formed extemporaneously by dissolving some of
the essential oil in spirit.
TITANIUM, ,_Ti. 24:, a rare metal, named by
Klaproth in 17 95 after the Titans. Its oxide occurs
crystallized in the minerals lilaniie or iii‘nnifei'ons iron
ore and enclose. When titaniferous ores of iron are
fused in iron smelting furnaces, small, brilliant, copper
coloured cubes, hard enough to scratch glass and in
the highest degree infusible, are found in the slag
and in the iron which collects in cavities in the hearth,
and is broken up when the stone work is renewed.
It was supposed until recently that these cubes con-
sisted of pure titanium; but they have been proved
by Wohler to consist of cyanide and nitride of
titanium, and to contain 18 per cent. of nitrogen and
4! per cent. of carbon. Metallic titanium has been
obtained artificially in a finely divided state. Titanic
acid Ti 02 is prepared from titanite: when pure it is
quite white, and in many respects resembles silica in
its behaviour.
TOBACCO. A French writer who has published
a book on the cultivation of tobacco and its manufac-
ture, states, that next to wheat, tobacco is grown in
France in larger quantities than any other vegetable;
and he gives as a reason the extensive consumption
of snuff, cigars and tobacco among all classes of
society, which so far from diminishing with the pro-
gress of civilization, appears to be largely on the
increase.1 Medical and other men have written a
good deal in a generaLway against the use of tobacco;
they have nothiiiigzyfeijy specific to urge against its
use. They argue nicotine, the active principle
of tobacco, is poisonous in its isolated form, the use

(1) “ Nouveau Manuel complet du Fabricant et de l’Amateur
de Tabac, 8:c. Par P. Ch. Joubert.” Published among the Manuela-
_ Beret, Paris, 13%.
31
850
TOBACCO.
of tobacco must be injurious. The experience of
1nanl<ind does not confirm the conclusion, although
We are bound to admit that the excessive use of
tobacco, as of everything else, is injurious.
Tobacco belongs to the monopetalous genus Nico-
zfe'cme, of which there are 40 species, most of which
f urnish tobacco for smoking. The word tobacco
appears to have been applied by the Caribbees to
the pipe in which they smoked the herb, while the
Spaniards distinguished the herb itself by that name.
The more probable derivation of the word is from a
place called Taeaco in Yucatan, from which the herb
Was first sent to Spain. The name Nieoiiarm is from
Jean Nicol: of Nismes in Languedoc, who was agent
to the king of France in Portugal, where he procured
tobacco seeds from a Dutchman who had brought them
from Florida. Nicot sent them to France in 1560,
and from that time tobacco has been cultivated in
various parts of Europe. In England its cultivation
in quantities sufficient for the purposes of manufac-
ture, is prohibited; so that with high duties, ranging
from 600 to 1,414t0 per cent., and amounting on an
average to 900 per cent., the cost of tobacco in Great
Britain is excessively and inj uriously high, thus giving
direct encouragement to the smuggler. It is stated
that in one year 70 cargoes of tobacco have been
smuggled between Waterford and the Giant’s Cause-
way, the quantity thus introduced being not less
than 3,500,0001bs.
Two principal varieties of Nicoiicma Tabaeum or
common tobacco are cultivated, viz. the Ororzoco and
the sweet-scented : they differ only in the form of the
leaves, those of the latter variety being shorter and
broader than the other.
They are annual herba-
ceous plants, rising
with strong erect
stems to the height of
from 6 to 9 feet, with
fine handsome foliage.
The stalk near the root
is often an inch and
more in diameter, and
surrounded by a hairy
clammy substance, of
a greenish yellow
colour. The leaves
are of a light green;
they grow alternately,
at intervals of 2 or 3
inches on the stalk;
they are oblong and
spear-shaped; those
lowest on the stalk are
about 20 inches long,
and they decrease as
they ascend. The young leaves when about 6 inches
long are of a deep green colour and rather smooth,
and as they approach maturity they become yellowish
and rougher on the surface. The flowers grow in
clusters from the extremities of the stalks; they are
yellow externally and of a delicate red within. The

Fig. 2176. TOBACCO.
(Nzcotiana Tabacum.)

flowers are succeeded by kidney shaped capsules of
a brown colour, each containing about 1,000 seeds.
A very large proportion of the tobacco consumed
in Europe is grown in Virginia and other parts of the
United States of America. The cultivation and
preparation of tobacco do not greatly vary with the
locality in any part of the world. Tobacco can only
be grown on good rich land, and the variations in
soils produce varieties in the herb. The seed is sewn
in nursery beds or patches, which are made of the
best possible soil in a dry place, and so situated that
they may be watered conveniently if the weather
should require it. The plant beds are got ready for
the reception of the seed in March or early in April ;
for which purpose heaps of brush-wood, straw, &c.
are burnt upon the land, which is then well dug up.
_White mustard—seed is sometimes sown round the
patch to entice the fly, which prefers mustard to
tobacco. Mats must be spread over the beds on the
slightest appearance of frost. In about a month the
sprouts will be 41 or 5 inches out of the ground, and
ready to be transplanted. The time should be selected
when the ground is well softened with rain, so that
the plants may be pulled up without injury to the
roots. They are then removed to a field prepared by
well breaking up the soil, and drawing the_mould with
the hoe round the leg of the labourer, so as to form a
hillock as high, as his knee; the foot is then with-
drawn and the hillock perfected. The hillocks are
arranged in lines, 4. feet apart one way and 3 feet the
other. A single root is carefully planted in each
hillock, and should a shower of rain follow, most of
the plants will succeed: should any fail, the farmer
waits until the weather becomes showery, and supplies
their place by new plants. The plants must be con
stantly weeded and dead leaves removed, and the soil
frequently stirred about the roots. When the plants
have attained the height of about 2 feet, and the
flower branches begin to appear, the plants are topped,
that is, the leading stem is nipped off with the finger
and thumb-nail; otherwise it would run up to flower
and seed, and so drain away much of the nutritive
juices from the leaves, to increase the size of which
is the object of the cultivator. After the topping,
from 5 to 9 leaves are left on the stem according to
the soil ; but the fewer the number of leaves that are
left the stronger will be the tobacco. Suckers or
superfluous sprouts about the root and near the
junction of the leaves with the stem must be pruned
off as they arise: this process, also performed with
the finger and thumb, is called sziclaeririg. The plant
is very liable to the attacks of grubs, some of which
prey on the roots and others on the leaves. They
require to be gathered individually and crushed under
foot. A continuance of very wet or very dry weather
also produces a disease called firing, in which the
leaves perish in spots.
When fully ripe the leaves change their colour to
a yellowish green; the web becomes more prominent,
and is thickened in substance. The plants must be
carefully watched, and such as are ripe must be cut.
If cut before they are fully ripe the leaves will not
TOBACCO.
851
acquire a good colour in the curing, and will also be
liable to rot when packed in hogsheads. In any but
intertropical climates the utmost vigilance is neces—
sary, for should frost appear the plants are entirely
destroyed. The plants are out near to the ground,
and those which have sufficiently thick stalks are cut
down the middle, so as nearly to divide them, in order
to facilitate the process of drying. The plants are
gathered after they have been acted on by the sun for
some hours. If removed from the field as soon as
out they would be broken and damaged, on account of
the rigidity and brittleness of the leaves. They are
conveyed to barns or curing lzouses, the sides of which
admit of being partially opened to promote the free
circulation of air, and within each barn poles are
stretched across about 41 feet apart: the poles are
connected together by cross pieces called locacco-
slz'clcs, on which the leaves are hung in order to be
cured. There are 3 distinct stages of these poles and
sticks within the barn, besides others in the roof-
The plants are suspended from the sticks 41 or 5 inches
apart, with the points of the leaves downwards, the
stalk of the lowest leaf serving as a hook, or the slit
made in the stem of the larger plants is made to
grasp the stick. The barn is thus filled from the roof
downwards. The temperature of the barn must be
kept tolerably uniform, and too much moisture got
rid of by small smothered fires of rotten wood and
bark made on different parts of the floor. In 4: or 5
weeks the tobacco ought to be in case; that is, when
the leaves are stretched over the ends of the fingers
and knuckles, they should be elastic and tough, and
slightly covered with a glossy kind of moisture. The
first rainy day is then selected for taking down the
leaves, and the next day they are stripped from the
stalks. The lower, or ground-leaves, being generally
soiled and torn, are separated from the rest; while of
those produced on the higher part of the stalk some
are inferior to others: the leaves are therefore dis-
tributed into 3 heaps. This being done, a number of
leaves are tied together at their thickest ends by
means of a small leaf twisted round the others, its end
being secured in a kind of knot: each small bundle of "
leaves is called a izarzd, and is somewhat thicker than
a man’s thumb at the end where it is tied. This
handling of tobacco, as it is called, should be per-
formed in rainy or damp weather, otherwise the leaves
will crumble into dust: and if the leaves have been
properly cured damp weather makes them tough.
The bundles or hands of tobacco are heaped together
on a wooden platform, where they undergo the process
of sweating .- this is a slight fermentation, which must
not be carried too far. When carried far enough,
the leaves, when stretched between the fingers, pos-
sess a certain elasticity by which the farmer knows
them to be in case for packing. Should symptoms of
decay begin to appear in the stalks in consequence of
unpropitious seasons, they are stripped off before the
leaves are packed. This operation is performed by
taking the leaf in one hand and the extremity of its
stem in the other, so as to tear them asunder in the
direction of the fibre, considerable expertness being

required in doing this properly. The stripped leaves
are of course only made up into bundles after the
stripping. If the stalks are sufficiently sound they
find a ready sale, as they are used in the manufacture
of certain kinds of snufi.
Tobacco is packed in hogsheads with considerable
compression, so as to render it less liable to change,
and less penetrable by moisture. The small bundles,
or hands, are ranged one by one, parallel to each other,
across the hogshead, their points all placed in the
same direction. In the next course, or layer, the
points are put in the opposite direction. Any vacant
spaces are filled up with small bundles, so that the
surface is made quite level: the thick ends of all the
hands are placed nearest the sides of the cask. When
the cask has been about 1-fourth filled, the prising
apparatus is used; this is a lever of the second kind,
the fulcrum being at one end, the power at the other,
and the compressing weight between the two. By
means of this apparatus the tobacco in the cask is
compressed into the thickness of about 3 inches.
Fresh layers of hands are added, and in their turn
compressed, and by repeating the operation several times,
the cask is at length filled. Several casks are in ope-
ration at the same time, the packers being engaged in
filling while some of the casks are under compression.
The hogshead used by the Virginian planters is 48
inches long, and from 30 to 32 inches diameter at
the ends, and will contain from 950 to 1,000 lbs. of
tobacco. .
Tobacco is cultivated throughout the East, and
particularly in the northern and western provinces of
India. The flavour of the Indian leaf is weaker than
that of American growth, which is attributed to want
of skill on the part of the curers. No plant of Euro—
pean introduction seems to be in such general request
as this throughout India; its consumption is almost
universal among the inhabitants of the Indian islands,
who grow all they require for their own use, while
some also export a portion. The Portuguese settlers
first introduced tobacco into these islands. In 1601
the Dutch introduced smoking into Java, in the hot
plains and valleys of which some fine tobacco has long
been grown; but as Mr. Porter remarks, the plant
“ so far gives evidence of its more northern origin as
to require to be first raised from seed upon the cooler
mountainous tracts of the island. This circumstance
occasions a peculiar arrangement: two perfectly dis-
tinct classes of husbandmen being engaged in the
cultivation. The seedlings are raised and sold by the
mountaineers to lowland farmers, who perfect the
plants, and again dispose of the seed to the former
class. This plan is found necessary to preserve the
plants from degenerating, which they would do if the
seed were sown at once in the hotter districts, while,
on the other hand, the soil of the mountains is ill
adapted for maturing the plants.ml The land is so
fertile, that the Javanese draw from it two annual
crops, one of rice and the other of tobacco.

(1)-The “Tropical Agrieulturist,” by G. R. Porter, 8Y0.
London, 1833.
312
8552
TOBACCO.
Tobacco may be grown in all warm and temperate
climates, but it succeeds better in some situations
than in others. , With the exception of a small spot
in the island of Martinico, where that peculiar fla-
voured leaf Mamba is produced, the tobacco of Cuba
is perhaps the finest in the world. Rio Negro and
Cumana, also, furnish a superior aromatic tobacco.
Varz'nas tobacco, grown in the Nuevo Reyno de
Grenada, is in repute. The S/tz'raz tobacco, so much
esteemed in the East for its delicate flavour and
aromatic quality, is raised from seed planted in De-
cember in a dark soil slightly manured: the ground
is covered with light thorny bushes to keep it warm,
and these are removed when the plants are a few
inches high. The ground is regularly watered if
required, and when the plants are 6 or 8 inches high
they are transplanted to the tops of ridges in a ground
trenched so as to retain water. When the plants are
30 to 40 inches high, the leaves vary from 3 to 15
inches in length; the flower capsules are pinched off;
the leaves increase in size until August and Septem-
ber, when the plants are cut off close to the root, and
again stuck firmly in the ground. By exposure to the
night dews the leaves change from green to yellow.
When of the proper tint, they are gathered in the
early morning while wet with dew, and heaped up in
a shed, the sides of which are closed in with light
thorny bushes, so as to be freely exposed to the wind.
Here, in 4t or 5 days, the desired pale yellow colour is
further developed. The stalks and centre stem of
each leaf are now removed and thrown away, while
the leaves are heaped together in the drying-house
for another 3 or 41 days, when they are fit for packing.
For this purpose the leaves are carefully spread on
each other, and formed into cakes 4: or 5 feet round,
and 3 to ll inches thick, care being taken not to break
or injure the leaves. Bags of strong cloth, thin and
open at the sides, are provided, into which the cakes
are pressed strongly down on each other. When the
bags are filled, they are placed in a separate drying-
house, and are turned every day. Water is sprinkled
on the cakes, if required, to prevent them from break-
ing. The leaf is valued for being thick, tough, of a
uniform light-yellow colour, and of an agreeable aro-
matic smell.
From the cultivation of tobacco we now proceed to
notice briefly its manufacture, which varies according
as it is intended to produce various kinds of tobacco
for smoking, various descriptions of cigars, and dif-
ferent kinds of snuff. Having recently visited the
Imperial Manufacture of Tobacco at Paris, we cannot
do better than notice the processes as we witnessed
them in that immense establishment.1

(1) The French Government has the exclusive right of manu-
facturing tobacco and snufi“ for the whole of the empire. The
central establishment at Paris, situated on the Quai d’Orsay,
gives employment to 1500 women and 500 men. The rooms are
spacious, well lighted and ventilated, and the machinery of good
construction and in excellent order. It is set in motion by a
steam-engine by Holcroft, of 140 horse-power. There are 10 manu-
factories in France, all depending on this the central one. It is
stated in Galignani’s Guide for 1850, that the annual profit to the
State on the tobacco monopoly, is about 90,000,000 francs
(£3,600,000), and that the quantity consumed, especially of cigars,

The store of tobacco on hand was very large, and
was continually increased by fresh arrivals. We saw
and examined tobacco of various growths, and could
not fail to remark the different aspects which they
presented. The largest proportion was Virginian, but
the supply from Holland, Belgium, France, Silesia,
the Lower Rhine, 850., showed that the cultivation of
tobacco is by no means neglected in Europe. There
was also a considerable amount of contraband tobacco,
which had been seized by the Government oflicers,
and was used chiefly for mixing with other sorts for
grinding up into snuff.
Passing over the unpacking of the hogsheads, &e.,
the first process, called Z’e’poularclage, consists in
separating the hands of tobacco, rubbing and shaking
them to make the leaves come apart, and to get rid of
sand, dust, &c. Soiled or mouldy parts of the leaf
are cutaway with scissors, and the leaves are then
sorted out into different baskets or boxes, according
to their quality; for it is found that every hand of
tobacco, although made up of leaves of nearly the
same quality previous to being packed, presents diifc-
rent qualities after having made a long voyage, or re-
mained compressed in the hogshead for a length of
time.
The sorted leaves are conveyed into an adjoining
room and sprinkled with a solution of 1 part sea-salt
in 10 of water, just suflieient to remove their brittle-
ness, and to make them sufliciently supple for sub-
sequent operations. The salt-water goes by the name
of sauce or liquor, and the operation of sprinkling, la
mom'llarle. The sauce sometimes contains sal-ammo—
niac, sugar, and other ingredients in addition to sea
salt: in this way some fancy tobaccos are concocted,
and certain manufacturers in different parts of Europe
make a great mystery respecting the composition of
their sauce. The salt is useful in checking the putre-
factive fermentation, but most of the other ingre-
dients must be condemned as useless or fraudulent?
The violet colour of the Mamba snuff of Martinique
is said to be due to the melasses contained in the
sauce. Liquorice juice in which a few figs have been
boiled, and bruised aniseeds added to the decoction,
has been recommended as a solvent for the salt, which
is to be added to saturation to the cold decoction, and
a small quantity of spirits of wine added. Sea-salt is
better than pure chloride of sodium for making the
sauce; because sea-salt contains minute proportions
of deliquescent salts, which tend to preserve the
moisture of the tobacco.

is increasing. There are about 500 licensed dealers in tobacco and
snufi' in Paris.
(2) The various ingredients with which tobacco and snutl‘ are
adulterated in Great Britain, are enumerated in one of the clauses
of the Act 5 and 6 Vict., which prohibits, under a penalty of
£200, manufacturers from having in their possession, “ any
sugar, treacle, melasses, or honey, or any commings or roots of
malt, or any ground or unground roasted grain, ground or un-
ground chicory, lime, sand, (not being tobacco sand,) umber,
ochre, or other earth, sea-weed, ground or powdered wood, moss,
or weeds, or anv leaves, or any herbs or plants (not being tobacco
leaves or plants) respectively, nor any substance or material,
syrup, liquid or preparation, matter or thing, to be used or capable
of being used as a substitute for or to increase the weight of
tobacco or snuff.” '
TOBACCO. 853
The next operation is to remove the stalk from the
lcai es of tobacco: this requires some dexterity, so as
not to tear or injure the leaf, and is usually done by
girls. In this operation, the largest and strongest
leaves are set apart by themselves, to be used as rates
or covers for the thicker kinds of pig-tail.
Next follows a more particular sorting of the leaves,
so as to bring together those portions which have the
same growth and distinctive qualities. The same
plant affords leaves of different colours and flavours,
and it is only by a skilful sorting at this stage, that
the characters of certain well-known tobaccos are
preserved, or the reputation of the particular country
or manufacture sustained. The tobacco thus sorted
may either be out or spun, or both. The leaves for
cutting are moistened with pure water, or with a very
weak solution of salt,and when sufliciently moist for l he
purpose, they are fed by hand into oscillating funnels,
through which they pass by compression under a
knife arranged very much like the knife of a chaff-
cutting machine. After each ascent of the knife, the
tobacco is moved forward about half a line, and the
descending knife cuts off that thickness from the pro-
truded end of the mass, and the cut fibres fall into a
trough beneath. The cut tobacco is then exposed
upon plates of iron heated by steam-pipes, the effect
of which, assisted by an occasional rolling motion
between the hands of the workman, is to make the
fibres curl. When this has been carried far enough,
the tobacco is removed to a heap, where it undergoes
a slight fermentation, after which it is spread out and
dried at ordinary or very moderate temperatures. In
England what is called bt'rzl’s eye tobacco is formed by
retaining in the leaf a portion of the stalk, transverse
sections of which dotted about among the fibres may
remind persons of strong imaginations of bird’s eyes.
Shag tobacco is formed of the darkest coloured leaves,
which are made darker by means of the liquor.
The other variety of tobacco, known in England as
pig-tail, is prepared by sprinkling the sorted leaves
with the sauce or liquor employed in lo nzonil-
larle, and leaving them to ferment until the desired
colour and flavour are attained. The leaves thus pre-
pared are spun into a rope or cord at a long bench,
at one end of which is a spinning-wheel turned by a
boy: a second boy arranges the tobacco leaves in a
line along the bench, making them overlap; a man
standing between the two boys rolls up the leaves
into a kind of cylinder, into which the boy at the
wheel throws the desired amount of twist. When
a length has thus been spun, it is wound upon a reel
to be afterwards made up into balls, which are
pressed, dried, and packed up for sale. The thicker
kinds of pigtail are prepared by wrapping tightly and
evenly round the thin cord produced by spinning the
stout leaves which were set aside when the stalks
were removed as already noticed.
Tobacco is sometimes imported in rolls or carrots,
as they are called, and the carrots are also formed at
the factory. For this purpose, the moist prepared
leaves are placed together in large handfuls, and are
wound tightly round by strips of dry fibrous wood or

grass; by this treatment, the leaves become partially
consolidated, and require only to be ground or raspcd
and sifted, to make the finest and most genuine snuff,
or mppce, as it is called.
The manufacture of cigars is a simple operation,
and at the French factory was performed entirely by
women. A bundle of fragments of leaves being
selected, a sound choice piece of leaf shaped like one
of the gores of a small globe is placed flat on the
work-bench; the bundle being placed across the
centre of this gore, is rolled up in it by passing the
hand flat over it; the point or nose of the cigar is
shaped with a pair of scissors, and secured by means
of a solution of gum and chicory; the cigar is next
placed against a gage, and a portion from the broad
end cutoff square. We have seen cigars made by
English and German workmen, and they appeared to
us to produce better shaped cigars and in a shorter
time than the French women, a result which we were
not prepared to expect. The cigars are tied up in
bundles of 25 in each, dried and kept for a time until
age has sufliciently mellowed them for use.
In the manufacture of snuff, the tobacco is consider-
ably modified by carrying the fermentation much fur-
ther than in tobacco intended for smoking, and is
imply ground and sifted. In the French factory, there
were about 30 mills, resembling large coffee mills, or
flake-cocoa mills [see CHOCOLATE, Fig. 570], only that
the grinding cone to each mill instead of the usual cir-
cular motion was connected with a lever and an excen-
tric, so as to produce half a revolution in one direc-
tion and half a revolution in the opposite direction.
By this reciprocating motion, the grinding cones do
not become heated, nor the teeth clogged. The
ground tobacco falls upon an endless band of broad
canvass, moving horizontally upon rollers, which con-
veys it to four sets of mechanical sieves, [see Srnvn,
Fig. 1973 ;] the snuff which passes through is received
upon an endless travelling band, which conveys it
some 12 or 15 feet into a close chest, and at the
turning point of this band a revolving brush sweeps
off the snuff into the chest. The particles which are
too coarse to pass through the sieve, escape by an
opening in the frame, and are conducted by a shoot
into a cylindrical trunk, in which an Archimedean
screw is playing, by which means they are conducted
back to the mills to be re-ground.
The immense varieties of snuffs are formed by
mixing together and grinding tobaccos of different
growths, and by varying the nature of the sauce. We
will give one or two examples of the preparation of
fancy snuffs. For the snuff known as Md’i'OCO, take
40 parts of genuine St. Omer (South American)
tobacco, 110 parts of St. Omer (European), 20 parts of
fermented Virginian stalks in powder ; the whole to be
ground andjsifted. Then take 212- lbs. of rose leaves, cut
them and mix with powdered Virginian stalks. Add
2% lbs. of rose-wood in fine powder, moisten with salt
water and incorporate the whole well together. Then
work it up with llb. of cream of tartar, 2lbs. of salt
of tartar, and 4.1115. of table salt. This snuff, which
is highly scented, must be preserved in lead.
8541
TOBACCO.
For Botongaro take 50 parts of Amersfort leaves of
the first quality, 25 parts of Virginian leaves, 25
parts of Virginian stalks. Grind the whole to fine
powder and sift.
The large-grained Paris snuff is composed of 50
parts Amersfort leaves, and 50 parts of the first
quality James River leaves, coarsely ground and
sifted. The sauce for this snuff is thus made: dis-
solve 12lbs. of salt and 41,1, lbs. of soda in 12 quarts
of boiling water: then boil for half an hour in a quart
of pure water 2slbs. of tamarinds, 1 pint of red wine,
Albs. of sirup of sugar, 1 pint of Cognac brandy,
then mix the whole with the former solution. This
tobacco is ready for use in 6 months.
The manufacture of tobacco in Great Britain does
not greatly differ from that of other countries; but
as the duties are so excessively high, the importer
examines his tobacco in the bonding warehouses of
the London Docks, and removes any portions which,
from defective packing, or from the action of sea—
water, &c. may have become injured. The damaged
portions are burnt in a furnace, familiarly known as
“the Queen’s tobacco-pipe;” the sound portion is
weighed and returned to the hogshead, and the duty
is charged on this portion only.
In the Great Exhibition, tobacco, both raw and
manufactured, was well represented. Mr. Benson’s
cases “ contained an epitome of the London tobacco
trade; and among them a box of Havannah cigars
ticketed ‘Flor de Cabanas, Partagas and Martinez
manufacture,’ stands preeminent for ‘evenness and
perfection of manufacture. The variously sized,
coloured, and formed cigars, in one box are stated to
be all the produce of the same crop of tobacco; dif-
ferences of colour and strength, and in some degree
of aroma, also depending upon the age of the leaf
employed and its position on the plant, the oldest or
lowest being used for the well known (and exten-
sively counterfeited) flat oily cigars called Braoas.1 ”
Among the American varieties was the Mason eonntg
leaf, which produces shag tobacco; the thin delicately
flavoured mild Ohio leaf, which furnishes the mild
Kanaster; the Virginian leaf, from which common
strong ship’s tobacco, used in the Royal Navy, is manu-
faetured. Hungarian tobacco, scarcely known in
Great Britain, of a fine and peculiarly delicate flavour,
superior to Tnrhish, was also exhibited. Messrs.
Lambert and Butler exhibited a specimen of English
grown tobacco: it was raised on a poor light soil in
Cambridgeshire; it was of excellent growth, but
deficient in flavour. Messrs Richardson of Edinburgh
had fine samples of pig-tail and twist tobacco, the
usual form in which the leaf is used in Scotland both
for chewing and smoking.
In noticing the tobacco from the East Indies, “the
Jury regret not having found samples of Awallan and
various other raw tobaccos, raised in different parts
of our Eastern possessions; or of the Dan/ea cheroots
made from tobacco grown on the banks of the
Godavery and Mahanuddy rivers, where its cultiva-

(1) Jury Report, Class II.

tion and manufacture are rapidly increasing, and the
cheroots are superior to any others from that part of
the world.” The most important exhibition of German
tobacco is that from Mannheim. That sent by W.
Jachs is pronounced superior in flavour and in point
of curing to any European tobacco known in the
English market. “ The Agricultural Society of Baden
has encouraged the culture of this crop, which has
rapidly increased to 200,0000wt. annually grown on the
banks of the Rhine. The cultivation is carried on by
small proprietors, and employs 20,000 hands; and the
produce is sold at a very cheap ,rate. It is exported
in leaf in vast quantities to England, Belgium, Spain,
and in bad seasons to the Havannah itself: and the
cigars are consumed in the United States to a great
amount. Great attention is paid to the selection of
fine covering leaves, upon the goodness of which the
burning and drawing so materially depend.” 5* “The Spanisn department excels all other in the
beauty and variety of its cigars. The best Havannah
tobacco farms are confined to a very narrow area on
the south—west of Cuba. This district, 27 leagues
long and only 7 bread, is bounded on the north by
mountains, on the south and west by the ocean, whilst
eastward, though there is no natural limit, the tobacco
sensibly degenerates in quality. A light sandy soil
and rather low situation suit the best.” Some of
the best cigars exhibited, named Ramas, the best
that can be produced, fetch 301. per 1,000 in the
Havannah. They were extremely fine in flavour,
perfect in burning, and so tightly rolled as to draw
with difficulty, which is considered by the Spaniards
as an advantage in this variety of cigar. The Spanish
department also contained a few Manitta cheroots,
and some beautiful samples of the Manilla leaf from
the three principal districts of the island, Visagas,
Ygarotes, and Cagayan. Portugal had also a good
exhibition of tobaceos and snuffs. There was also
a large assortment from Algiers, which is becoming
the great tobacco mart of France. The Turkish col-
lection of bazaar tobaecos was extensive, the samples
particularly fine and abundant. “Latahia of the
best quality is exhibited here, dark in colour and of a
good tarry flavour. The Moldavian tobacco is also
particularly fine.” Persia exhibited the celebrated
Ahnriha or “Father of Perfumes,” in two samples,
“ one, the ordinary dark-coloured, in leaf; the other,
loosely twisted into a roll, is paler, more prized in the
country, and given as presents among the nobles. It
is much too mild for appreciation in England, however
delicate the flavour. The Damascus tobacco is of the
same quality as the celebrated Shiraz, pale-coloured,
but rather thick and firm in the leaf, and very strong.”
Russian-grown tobacco is referred to as being “ very
mild and rather sweet-flavoured, though not equal in
aroma to the Havannah cigarillas.” The exhibition
from the United States of America “ is chiefly of
Cavendish tobacco, and. is both extensive and admir
able; the contributions of many makers attesting the
importance of the manufacture and the prevalence of
chewing, for which these are principally used in the
United States ; whilst in England they are most prized
TOLU—TONKA BEAN--TOPAZ--TOBTOISESHELL.
855
as the strongest and best flavoured for smoking. The
finest Virginia leaf is used in the manufacture, which
consists chiefly in curing and pressing the leaf into
fiat square cakes of various sizes, a little molasses or
sugar being sometimes added.”
The importation of tobacco into the United
Kingdom for the following years is thus stated :--
Entered for home
Imported. consumption.
1849 42,098,1261bs. 27,480,6661bs.
1850 . 35,162,099 27,538,104 1851 31,049,554 27,853,253 1852 Unmanufactnred Tobacco 31,061,953 . . 27,853,390 Manufactured and snufi' 2,331,886 209,588
The gross amount of duty received on these two
quantities in 1852, was 4,386,910l. and 98,8581.
TOBACCO-PIPE. See Porrnnr AND PORCELAIN,
Sect. 1V.
TODDY. See Coco-NUT TREE—SUGAR.
TQLU, a balsam, the produce of a tree, Myrosper-
mum tolaijleram, growing on the mountains of Tolu
and Turbaco, and on the banks of the Magdalena.
Incisions are made in the bark, and the balsam ex-
udes during the heat of the day. It is collected in
earthen crocks and calabashes; but it is often im-
ported in tin canisters. It is soft and tenacious when
fresh, but hardens in the course of time: it is trans-
lucent, brown, fragrant, and has a slightly sweet
taste. It fuses and takes fire when heated, and
exhales an agreeable odour. Tolu resembles Peru
balsam, and consists of cinnaméine, cinnamic acid,
and resin. By dry distillation, Tolu balsam yields
benzoic acid mixed with a little cinnamic acid, and a
yellow liquid, probably a mixture of Zolaole (014118)
and benzoic ether.
What is called Mac/c balsam if Tola is said to be
procured by boiling the resinous bark and branches
of the tree. Both kinds are much adultcrated with
the turpentines, copaivi or volatile oils. See BAL-
SAM.
TOMBAC is one of the alloys of copper and zinc,
containing a larger proportion of copper than exists
in brass, and made by fusing copper with brass.
Dated-gold, Similar, Prince Rapert’s metal, and Pine/@-
baa/a, are alloys similarly produced. See BRASS.
TONKA-BEAN, the fruit of Ooamarowza 0610mm.
It yields a camphor named Cour/‘amino, or Coumarylic
acid, 018E704-
TOOL. See MACHINE—ENGINE.
TOPAZ. The topaz is found in primitive rocks in
Cornwall, Scotland, Saxony, Siberia, Brazil, and other
parts of the world. The following analyses are (Nos. 1
and 3) of Saxon topazes, and (Nos. 2 and 4) of Bra-
zilian topazes :—

(L) (2-) (7t) (4-)
Silica................. 35 445 34'24 34'01
Alumina .......... .. 59 4/’ '5 57 '45 5838
Fluoric Acid .... .. 5 7'0 7'75 7'79
Oxide of Iron..... 0‘5
99 995 99'4-1» 100'18
Brazilian topazes are of a yellow, 2. blue, or a white
colour; the first is the best known, and the last is
more commonly termed lll'iaa Nova, from Minas
Novas, the name of the place which produces the‘

finest crystals for the lapidary. The oriental topaz is
a yellow variety of SAPPHIRE. For the purposes of
jewellery the colour of the topaz is often changed by
the action of heat. The ‘Brazilian topaz assumes a
pink or red hue so much like the Balas ruby, that it
is only distinguishable by the facility with which it
becomes electric by friction. Topaz pebbles are some-
times called goaz‘ies alarm, or “ drops of water,” from
their peculiar limpidity; and when out with facets,
and set in rings, they may be mistaken by day for
diamonds. The topaz is usually cut in the form of the
brilliant or table, and is set with gold foil or a joar.
In the Russian department of the Great Exhibition
was a beautiful stone labelled P/zaaalvz'z‘a; it was of
a bluish colour, and very brilliant. Various opinions
were pronounced respecting it: it was thought to be
a beryl, an aquamarine, or a topaz. The owner was
willing to test its hardness by scratching, but at the
suggestion of Professor Tennant it was decided, as the
safer test, to take its specific gravity. This was ac-
cordingly done, and on comparing it with a topaz in
its natural state, the result was precisely the same,
viz. 35, whereas the specific gravity of phenakite1
is 2'7.
TORSION.
TERIALS.
TORTOISESHELL. The covering of a marine
animal, Taszfaclo imt'rz'cata, or the hawk’s-bill turtle or
tortoise, a native of the torrid zone. The back, in
this species of turtle, is arched over with a beautiful
variegated substance employed in the arts as a mate-
rial for combs, work-boxes, tea—caddies, cabinets,
spectacle-cases, &c. This substance is formed in
plates or layers, 13 in number, which overlap each
other, and are surrounded by 25 much smaller plates,
forming the margin to the shell. Less beautiful plates
cover all the turtle species, but these generally ad-
here to each other at their edges; whereas, in the
tortoise, they are imbricated, falling over each other
like the tiles of a roof. The size and thickness of the
plates, technically called Hades, vary with the age of
the animal: a new layer of horny substance is pro-
duced every year, and thus each plate, at its exposed
edge, marks the age of the tortoise. At its full
growth, this animal measures about 3 feet, but in-
stances have occurred of its reaching a or 5 feet.
The belly plates of the tortoise, which are not va-
riegated, but plain yellow, are sometimes sufiiciently
clear to be made use of. Among the back plates
there is also much diversity in shade, colour, and
marking. The rich dark-brown shell, with occasional
markings of golden—yellow, is the most prized in the
market, but there is also a demand for the lighter
varieties, some of which are very elegant. Some parts
of plates, or particular varieties, present an almost
uniform tint, so that combs of a light red, or pale-
yellow or brown, maybe manufactured almost without
sign of variegation. Such combs are greatly prized,
it appears, by Spanish ladies, who will give double
See ELASTICITY—STRENGH of MA

(I) Phenakite or Phenacite is a variety of Chrysoberyl, and con-
tains silica 55-1. glucina 44-5, with a trace of magnesia and
alumina.
856
TORTOISESBIELL.
the price for a plain comb which they would give for
a mottled one. In this country plain shell is little used
except for inferior purposes; and there is a shell
almost colourless, which is used for covering the
works of the better kind of musical snuff-boxes. To
the same purpose is also applied the belly-plate of the
turtle, which is less transparent than tortoiseshell.
The term shell is, as we have already stated, [see
Honm] inappropriate to the covering of the tortoise,
which consists of a layer of gelatinous matter formed
on the bony arch of the back, and answering to the
epidermis in other animals. When this substance is
examined under the microscope it presents a series of
flattened cells, which, however, may be dilated to a
spherical form under the influence of a solution of
potash and heat.
Some of the finest tortoiseshell is obtained from
Manilla, and from Singapore: the West Indian varie-
ties are large and heavy, but not often so beautifully
coloured. Some very fine specimens from Ceylon,
from Labuan, and from Trinidad, appeared in the
Great Exhibition of 1851. Tortoiseshell is liable to
much injury from the attachment of limpets, bar-
nacles, &c., to the living animal: this hinders the
growth of the shell at that particular spot, and causes
an appearance on the shell known among dealers as
sea/Boy, which destroys its value.
The method of detaching the tortoiseshell from its
bony axis is not, as in the case of horn, by a slow
process of maceration in water, it is simply edected
by placing the shell over a fire, which soon causes the
plates to start away from the bone, the separation
being assisted by a thin knife.
The preparation of tortoiseshell for the purpose of
the manufacture is similar to that of horn; it is
softened in boiling water in the same way, but with
greater care, as too much boiling destroys the beauty
of the colours. An addition of common salt to the
water prevents in some degree this injury; but here,
again, caution is needful, as too strong a brine is apt
to make the shell very brittle. Tortoiseshell possesses
the useful property of welding. Pieces of shell can
be perfectly united, by scraping and thinning down
their edges, and then overlapping these edges, and
fixing the shell in a screw press. The press is put
into boiling water, and tightened from time to time.
In this way, in the course of a few hours, and with-
out injury to the colours of the shell, the joining is
ell'ected. The same result may be obtained by the
dry heat of tongs or irons ; this is a quicker process,
but requiring more care, or the colours will be spoiled.
For small joins, a pair of tongs with flat ends will
answer the purpose. The slips of shell to be joined
are filed down to a very thin edge, the one on the
upper, the other on the lower surface; if the join is
to occur in the curved part of the intended object,
the slips are dipped in boiling water, and bent to the
required form; the surfaces are then united, and held
firmly between the finger and thumb, while the piece
is dipped in cold water to make it retain its form.
The faces of the joint are then slipped asunder and
filed once more, to remove any grease, which would

prevent the union of the parts. A bit of clean damp
linen folded many times is then placed each side the
joint, to preserve it from the direct action of the hot
iron, and the whole is then inserted between the
tongs, which have been previously made hot enough
to colour writing—paper yellow. These are now fixed
in the jaws of a common vice, and moderately
tightened. The work may be left to cool in the vice
or it may be dipped in cold water. For larger works,
a flat iron may be employed to give the required heat,
moistening the shell at intervals to prevent burning,
but the dry heat of the iron deepens the colour
greatly, and sometimes makes it quite black.
The methods and machinery employed in making
tortoiseshell and other combs have been described
under COMB. It has there been shown that great
economy in the use of this valuable material is effected
by cutting two sets of teeth at once. A similar care
to avoid waste is shown in making spectacle-frames
and eye-glass frames. Formerly these were made by
cutting a circular hole in the tortoiseshell of the size
to be occupied by the glass; and the waste disks
were laid aside to be used as occasion might oli'er in
inlaid boxes, &c. The outer part of the frame was
then shaped with saws and files. This evidently re-
quired a piece of tortoiseshell as large as the whole
frame; whereas at the present day in all ordinary
frames a narrow piece of the material is cut, and two
slits are made in it with a thin saw. When the shell
is softened by heat, these slits can be pulled out into
circular holes and fashioned to the appropriate form.
The groove for the edge of the glass is cut with a
small circular cutter, about half an inch in diameter,
and the glass is slipped in when the frame is expanded
by heat. This is only one out of many instances
in which the flexibility of tortoiseshell is turned to
economical account; it also accounts for the slight-
ness and brittleness of modern articles in tortoiseshell
compared with those of older date. All this pulling
and straining of the material obviously eeonomises it
at the expense of strength and durability.
Tortoiseshell boxes and other moulded works are
largely made, and require the use of a copper, a
trough for cold water, a press, moulds, &c. The
mould for a round box is a wrought-iron cylinder,
turned to the diameter of the box. It stands on a
plate of the same, and is provided with several ac-
curately fitting pieces of brass, which form the dies,
either plain or engraved, which are to give the desired
form and surface to the box. In the best kind of
boxes the cover and the bottom are each made of a
single leaf of shell: this is cut out in a circular form
as much larger than the size of the box as the vertical
height in addition to the diameter. Thus a box of
three inches diameter and one inch depth, would
require a piece of shell four inches in diameter for
the cover, and another piece five inches in diameter,
for the bottom. The round plate of shell is first laid
on the top of the cylindrical mould. A small round
edge block is then pressed. slightly upon it; the whole
is lowered into boiling water, where in 20 or 30
minutes the tortoiseshell becomes so soft that the
TRIPOLL—TRITURATION.
857
block can be pressed into the mould, carrying the
tortoiseshell with it, and moulding it into a saucer
shape. The process is repeated with difi’erent dies to
give the exact form required, and the work is after-
wards completed at the lathe. Inferior boxes can be
made by carefully fitting together with the file frag-
ments of tortoiseshell having bevelled edges. These
are arranged along the bottom and up the sides of
the mould, or they can be made into a flat plate in
the first instance, and then made into a box by the
process just described; but the joints in such boxes
are nearly always visible.
Even the fine dust and filings of tortoiseshell are
used by our ingenious neighbours, the French, in
making boxes. The filings are sifted, softened,
moulded, and formed into inferior and nearly opaque
boxes, which often have a thin hoop of good tortoise—
shell inserted in the mould to form the rabate of the
box, and so improve the general appearance. Some-
times the shavings are mixed with mineral colouring
matters to imitate lapis-lazuli, granite, and other
stones. This kind of manufacture is almost unknown
in England, where tortoiseshell boxes are usually
veneered upon a body of wood, the plates being
reduced to uniform thinness, and glued on as in other
kinds of veneered work. But that the shell may not
lose any of its effect, it is rubbed at the back either
partially or entirely, according to taste, with a
mixture of rich colours in fish-glue: this serves to
hide the wood on which the veneer is to be placed,
and also artificially enhances the brilliancy of the
tortoiseshell. When a surface of tortoiseshell has to
be inlaid with mother-of-pearl, gold, silver, &c., the
ornaments are arranged in the required form on a
plate of tortoiseshell, which rests on a. bed or cushion
of tortoiseshell filings within the mould, a thin paper
keeping the filings from adhering to the plate. The
top die plate is then steadily lowered, the mould is
placed in the press, and the whole is plunged into the
copper for an hour, when it is examined to see that
nothing is misplaced. It is again returned to the
copper for a time, and then powerfully pressed by the
force of three men, and while still under pressure, it
is plunged into cold water. A beautiful inlaid plate
is thus formed by pressing the pearl, 850. into the
very substance of the shell. This is now fit to be
smoothed, and glued on to the surface of the box or
other article to be veneered. Hollow walking—sticks
are made of Gortoiscshell, and in the British Museum
is a tortoiseshell bonnet.
TOUCH-NEEDLES. See ASSAYING.
TOW. See FIAX.
TRAGACANTH. See GUM.
TRASS. See Mon'rxns AND Cnnnurs.
TREACLE. See Susan.
TRIPOLI, a fine grained earthy deposit, with a dry
harsh feeling, and a grey, yellow, or red colour. It
contains 81 per cent. of silica, mostly derived from
the casts or skeletons of infusorial animalculae, 1'5
per cent. of alumina, 8 per cent. of iron, sulphuric
acid 3'45, and water a 55. The forms of the animal-
culae are readily distinguished by the microscope, and

their analogies with living species may be traced: in
many cases, according to Ehrenberg, the petrified
appear to be identical with the living. The species
are distinguished by the number of transverse lines on
their bodies: the length is about é-é’g'th of a. line.
Tripoli was first brought from Tripoli in Africa as a
polishing material, but has since been found in France, .
Italy, Germany, and other places. Rerl Tripoli is
prepared in large quantities from a brick earth found
near Battle in Sussex. When burned in lumps it is
as heavy as emery stone; it is then ground and
sifted, and resembles crocus, only coarser: it is used
for similar purposes. A red tripoli is also prepared
by calcining and pulverizing the clnnc/i or curl
alone of the coal and iron districts of Stalfordshire,
formerly used only for mending the roads. It is
composed of iron, alumina, lime, and silex. Clunch
resembles the septaria nodules, used as the basis of
Roman cement. [See Monrans and CnMnnrs] Mr.
Gill says, “ the polishing effects of the calcined and
pulverized clunch are superior to those of the septaria
when prepared in a similar manner; and are indeed,
in point of quickness of action in producing the polish,
and in the beautiful black lustre which it gives to the
gold or silver, far beyond anything I have ever met
with.”
Yellow or French Tripoli, as it is called, is used
for the general purposes of polishing. It is also
used for polishing light-coloured woods that would
be stained by the absorption of darker powders into
their pores. A large quantity of fine yellow tripoli
was obtained in digging the canal in the Itegent’s
Park, London. See RorrnN-sroxE—Gnmnme and
POLISHING.
TRITURATION, the process of reducing solids
to powder, in order to assist solution or chemical
action. It is generally conducted dry; whereas in
levigation the comminution is assisted by a liquid,
[See Lnvrea'rrou] When the substance is ground
with a muller on a porphyry or other slab, the process
is termed poip/tyrisalion.
The pestle and mortar are most commonly em-
ployed in trituration, but edge-rollers are often used
where the pulverized substance is required daily in
large quantities. [See CHICORY, Fig. 566.] Grind-
ing in steel-mills, as in the case of coffee, pepper,
&c., is resorted to where practicable, and grindstones
are used in reducing corn and flour.
In the laboratory pestles and mortars are of various
sizes, materials, and forms. A large iron mortar with
a pestle of the same material is used for breaking
large lumps into smaller, and for the pulverization of
ores, metals and heavy coarse substances. Smaller
mortars formed of earthy materials are used for the
pulverization, and sometimes the solution, of various
bodies. Such mortars ought to be “so hard as to
bear the blows and friction of other hard bodies for
any length of time, without suffering injury or
abrasion of the surface; of a uniform and compact
texture; not brittle; not permitting the absorption
of fluids or penetration by them; not subject to the
action of acids, alkalies or other solutions; and of a
858
TRITURATION.
requisite capacity.M The manufactured substance
which best combines these various qualities is Wedg-
wood ware; but mortars in this ware are not made
of sufficient size or thickness. Probably the very
best material for mortars would be porphyry; but it
is very expensive to work. Some years ago a number
of slabs and mortars in this material were sent from
the continent; they did not find a ready sale on ac-
count of their high price; but Mr. Bell, of Oxford
Street, purchased a triturating mortar, 29 inches in
diameter, for 50 guineas: it has proved a valuable
implement in the laboratory, resisting the action of
chemical agents, and being sufficiently hard and strong
to bear contusions and the rougher processes of
trituration.
A good Wedgwood ware mortar should not be
capable of being scratched with the edge of a piece of
quartz, or flint, or stcel. It should not receive a
permanent stain if a solution of sulphate of copper or
muriate of iron be left in it for 241 hours. On rubbing
down an ounce of sharp sand to fine powder, the sand
should not acquire any appreciable increase in weight.
The proportionate thickness of the mortar in different
parts should be somewhat as in Fig. 2177. The
pestle should be of
one piece, and of the
same material and
qualities as the mortar.
If the handle be of
wood and the bottom
of ware, the two are
apt to separate. The diameter of the lower part of
the pestle may be about one-third or one-fourth of
the upper diameter of the mortar. “The curve at
the bottom should be of shorter radius than the curve
of the mortar, that it may not touch the mortar in
more than one part, whilst at the same time the
interval around may gradually increase, though not
too rapidly, towards the upper part of the pestle. A
mortar and pestle of the relative convexity given in
Fig. 217 8, may, by inclining the pestle, or bringing it
to different parts of the mortar, allow portions of such
different curvature to be placed in juxtaposition that
the intervening space shall increase more or'less
rapidly from the point of contact in almost any pro-
portion; a variation which it is of considerable con-
sequence in pulverization to obtain with facility.”
Neither pestle nor mortar should be quite smooth at
the grinding surfaces; but the required roughness is
best obtained by use. Mortars should be lipped, for
the convenience of pouring.
Small mortars and pestles are made of agate, and
are useful for the pulverization and mixture of small
portions of matter. They are made shallow, and
are exceedingly hard. Steel mortars for pulverizing
diamonds are noticed under LAPIDARY WORK, Fig.
1272.
Some knowledge and experience are required for
Fag. 2178.


(1) Faraday, “Chemical Manipulation,” sec. v. The reader
interested in the subject, will do well to study the whole of this
section. He will also find further information thereon in Moln-
and Bedwootl’s " Practical Pharmacy,” 1849.

the successful use of the pestle and mortar. Some
methods of grinding or managing the pestle are for cer-
tain substances preferable to others. Some substances
undergo comminution when acted on in one particular
direction; sal ammoniac, for example, should have the
grain upright in the mortar, not horizontal. Stony,
hard substances may often be more easily reduced by
igniting and then quenching in water before grinding.
Charcoal may be powdered more readily when hot
than when cold. Camphor is tough under the pestle,
but if moistened with a few drops of spirit of wine it
crumbles readily. Zinc may be powdered while hot
in a heated iron mortar with a hot pestle. Some
adhesive organic substances require to be mixed with
clean dry sand in order to be triturated.
In the trituration of drugs a marble or Wedgwood-
ware mortar is often used with a pestle of lignum~
vitae, or other hard wood. The pestle may also be of
marble or stone, with a long handle passed through a
ring fixed to the wall 41 or 5 feet above the mortar.
Marble is objectionable for mortars on account of its
being acted on by acid salts and other substances,
and the surface is readily abraded. Dolomite or
magnesian limestone has been recommended. Glass
mortars are soft and brittle, and yield both alkali and
lead to particular solvents. Mortars of wood, marble,
or iron, are seldom used in the chemical laboratory.
The process of porphyrisation is used to a great
extent for grinding colours. The substance to be
triturated is put on the slab in the form of a coarse
powder, and if unacted on by water it is formed into
a thick magma therewith. It is then distributed into
a thin stratum, and triturated by the muller, which is
grasped with both hands, and rubbed with some pres-
sure over the surface, following some curved figure,
such as that of the figure 8, or intersecting circles;
but the figures are alternated from time to time to
bring fresh particles under the action of the mullcr.
By thus extending the comminution on a very thin
layer spread over a large surface, the action is more
complete than with the pestle and mortar. A slate
slab is sometimes used, with a large number of mul—

Fig. 2179.
lers moved in difi’ereut directions by machinery, as in
the manufacture of blue-pill and mercurial ointment.
In the porcelain manufactory at Sevres, a peculiar
kind of mill or mortar, made of porcelain or glass, is
TUBES AND PIPES.
859
used for grinding the colours. It consists of a mortar
M M, Fig. 217 9 , with a projecting conical piece 0 in
the centre, which forms, with the sides of the mortar,
a circular trough, in which the pestle or mill Pr’
moves. This pestle is a cylinder of porcelain rounded
at the bottom 1?‘ P‘, as shown separately in the lower
figure 1? r, and weighted with a disk of lead L at the
top, and moved round by the handle H. This mortar
acts with great expedition and effect; but M. Broug-
niart states that it does not produce suficient tenuity
in the colours used for painting on porcelain, for they
have to be finished by porphyrisation; but in pre-
paring for this process the mill is valuable.
TRUSSING. See Canrnnrnv.
TUBES AND PIPES. The excellence which has
been attained in the manufacture of certain kinds of
tubes and pipes is due to a certain extent to the vast
demand for gun-barrels during the late war, [see
GUN,] but chiefly to the adoption of the tubular
system in marine boilers. [See STEAM Enema] The
tubes in marine boilers are about 315th inch thick, and
as large as 3 inches in diameter when coal is used as
fuel; but in locomotives where coke is burned, the
tubes are only about one half the bore of those used
in marine boilers. The tubes for locomotives are
sometimes of wrought-iron, but more commonly of
brass. Thick tubes would be too heavy either for
marine or locomotive boilers. A brief notice of the
more important patents that have been taken out for
improved methods of making gun—barrels and gas-
pipes, 820. will show the gradual advance that has
been made in this important manufactm'e.
In 1808, Cook of Birmingham patented 3 methods
of making barrels: 1. To forge a round bar of iron
of a short length; to drill a hole in it, and to elongate
the barrel by means of drawplates or grooved rollers,
in either case with a mandril in the barrel. 2. To
turn a short plate of iron or steel over a mandril or
beak~iron, to weld it by hand, and then to elongate
the barrel by drawing, 850. as before. 8. To force a
circular plate of metal through a series of holes in a
die, so as to raise it into a cup shape, which was to be
elongated as before. None of these plans succeeded.
In James and Jones’s patent, 1811, there are two
methods of welding. 1. The plate of iron was turned
over into the shape of a barrel with the edges in a
position for welding, and a portion of the barrel being
raised to a welding heat was placed on a hollow anvil
having several grooves to correspond with the barrel:
then by hammers worked by machinery, the heated
part of the barrel was welded, a stamp or mandril
being placed within the barrel. .2. It is proposed to
use grooved rollers, the grooves being of the figures
of the barrels, a mandril being used.
1817. Osborne’s patent for a new method of pro-
ducing cylinders—By a previous patent the plates of
iron were turned by grooved rollers ready for welding
into barrels; by the present patent grooved rollers are
used for welding as in James and Jones’s patent,
but the method of using the mandril is different A
shield attached to the mandril prevented it from being
drawn through between the grooved rollers in weld-

ing a cylinder or barrel on it. The unwelded barrel
being raised to a welding heat, the mandril was
inserted and conveyed to the rollers, the mandril
being retained by stops which prevented the shield
from passing; so that the barrel as it was welded by
the rollers was drawn olf the mandril, the mandril
keeping the bore open and preventing the iron from
being rolled into a solid mass. The weld was thus
made, and by heating the barrel several times and
passing it between grooved rollers with a succession
of mandrils the barrel was drawn out to the desired
length. Most of the gun-barrels of Birmingham have
been welded by this plan. See GUN.
In 1824, Bussell’s patent for welding iron tubes by
means of a hollow hammer and tool, the latter to
hold the tube while receiving the blows of the former.
It was found that if the tube fitted the hollow tool
and hammer, no efiect was produced; and if too large
for the hollow the tube was crushed, and so this plan
failed.
In 1825, Whitehouse suggested that a tube might
be formed and welded by external pressure only,
without internal support. The skelps or plates of
iron being turned up into the circular form ready for
welding, about half the length was raised to a welding
heat, and then, by means of the chain of a draw bench,
it was drawn after the manner of wire through a pair
of tongs with two bell—mouthed jaws, which are
opened by means of handles for introducing the end
of the skelp, and then forcibly closed upon it while
the draw bench did its work. Or the jaws or two
halves of the die might be opened and closed by a
screw. Grooved rollers capable of giving complete
circumferential pressure, but with no internal sup—
porting mandril, also fell within the claims of this
simple and useful invention.
1831, Royl’s patent (held to be an infringement of
Whitehouse’s,) was for the use of 2 grooved rollers in
front of the furnace, so that the prepared tube at the
proper heat should be drawn out and welded by the
rollers. To facilitate the working, the upper roller
could be separated from the under one, by which the
tube could be moved between the rollers, and when
the’ upper roller was brought to the lower roller and
motion imparted to them the tube was run out of the
furnace and welded. ‘The tubes were then passed
through dies to improve their shapes.
1886. Harvey and Brown’s patent—The mandril
was a short instrument, fixed in front of the rollers,
so that the enlarged head came just in the pinch of
the rollers; and, in working, the heated tube was
forced over the short, cranked stem of the mandril,
the unelosed seam of the tube being sufficiently open
to allow it to pass the fin by which the stem of the
mandril was carried.
Bussell’s patent, 1836, was for making welded iron
tubes without first turning up the iron plate, but only
a few inches of the length, and then, by means of the
apparatus in front of the furnace, the plate of iron at
the welding-heat was first turned into the shape of
a tube and welded at the same time by dyes or rollers,
as in Whitehouse’s patent.
860
TUBES AND PIPES.
Prosser’s patent, 1840, for improvements in the
machinery for manufacturing pipes.--1t was proposed
to use a combination of 3 or a. rollers. With the latter
number each roll is formed with a groove exactly
equal to the quadrant of the circumferential section
of the pipe, and bevelled off at 115°,
so that the combination of the 4
rollers completes the circle, as shown
_ in Fig. 2180. The 4: rollers were
connected with equal wheels, so as
v to travel with the same velocity.
Fi-‘J- 218°- The method of working was as
follows :——The end of the strip of iron which was to
form the tube was bent into a circle, and the strip
being raised to the welding heat, the rollers carried
it forward and deposited the welded tube upon a
long supporting mandril, smaller than the bore of the
tube, and opposite the rollers. When 3 rollers were
employed, each roller included 1-third of the circle.
Russell and l/Vhitehouse’s patent, 18412, for welding
very thin iron tubes with scarf or lap-joints for steam-
boilers—The mandril was much smaller than the in-
’<‘\ tended tube which was welded
17" ,
_
by passing the tube, with the
.Fig.2l$l.


mandril in it, Fig. 2181, between
grooved rollers or through hell-
mouthed dies, the hole being of
an oval shape. When making the weld the man~
dril was set fast in the tube throughout its length;
but on passing the welded tube through dies with a
circular opening, the tube became cylindrical and the
mandril was then readily withdrawn. The pressure
of the roller or dies first acted on the outer edge of
the lap—joint, then on the inner, and lastly on the
central part; the three processes were accomplished
at one heat, and the diametrieal line upon which
the pressure was applied became, for the time, the
shorter diameter of the oval.
Messrs. Russell’s patent, 18414:, for welding large
tubes for boilers, 850., consisted of a moving hollow
bed, on which the prepared tube was placed; and the
bed with the tube was passed under a grooved roller.
A fixed mandril was used within the pipe to give sup-
port and resistance while the roller passed over the
pipe and made the weld. The end of the tube being
fixed to the hollow bed, this, in its movement, carried
with it the tube, and caused it to pass over the man-
dril and under the pressing or welding roller.
Russell’s patent, 18115, for welding iron tubes—A
long fixed bar or beak-iron is supported at one end,
and on this is placed the tube to be welded; the tube
being at the proper heat, and the edges overlapping
so as to produce a lap-joint. The weld is then pro-
duced by drawing the tube of the beak-iron under a
grooved roller situatedabove the end of the beak-iron,
which must not be less than half as long as the tube,
which is welded at two processes,
Banister’s patent, 184:9.—-Th1'66 tubes of different
metals, brass, iron, and copper, are placed one within
the other, the brass being inside, the copper out: a
slightly tapering mandril is then introduced, and this
compound tube is drawn through a series of dies until


the metals are closely combined. As the metals are in
a soft state when put together, it is not necessary to
anneal them in the moderate drawing to which they
are subjected. The benefits of this combination are,
that brass is used where there is a rush of flame and
the products of combustion are formed; the copper is
next the water, and the whole is stiffened by the use
of iron. When, however, the the acts on the exterior
of the tubes the order of arrangement must be re-
versed. This patent also includes a new method of
soldering the joints of the tubes. The metal having
been bent until the edges come together, they are filed
with a triangular file into a sort of gutter. The tube
is then filled with sand: it is also covered on the
outside with sand, in which a gutter is made over the
gutter formed by the chamfered edges: the tube is
then heated to bright redness, and melted metal,
similar to that of the tube, is poured into the gutter,
whereby the edges of the tube are partly fused, and
the whole settles in cooling into a solid mass. The
projecting ridge of metal on the seam is cut oil’ by
means of a circular saw or otherwise.
The peculiarity of the modern manufacture of tubes
is the absence of internal support. The mandril,
which appears to be so necessary, (as indeed it is
when gun-barrels are forged by the side blows of
hand-hammers upon anvils or swages,) is in fact an
incumbrance, for when it fits tightly it disturbs the
progress of the tube over it, and spoils the work.
The mandril should be used, not as a mould, but
simply as a support; it should not fit the tube, but
merely serve to hold it while in its heated and flexible
state.
The furnace for heating the tubes is of importance:
it should be of the full length of the longest tube,
and be uniformly heated. The reverberatory form is
generally adopted. Mr. Prosser’s furnace has a door
at each end for the entry and removal of the skelp,
and on one side are a number of stoke-holes for the
introduction of the fuel: in the opposite wall, beyond
the bridge of the furnace, are corresponding aper-
tures leading into a longitudinal chamber parallel
with the fire, and thence into a lofty flue. The fur-
nace is made to-burn with equal intensity throughout
its length by regulating the dimensions of the aper-
tures. When the iron is raised to the welding-heat
it must be quickly removed from the furnace, or it
will be spoiled.
There is an extensive demand for brass tubes, such
as are used for telescopes, which require to be very
true. The brass tubes for common purposes are bent
up, and soldered edge to edge, (as described under
Sonnnnnve) and are then drawn through a hole,
which produces a roundness and smoothness on the
surface, but leaves the interior rough. The tubes for
telescopes are drawn inside and out through a hole in
a thick draw-plate pp, Fig. 2182, the soldered tube
being first forced upon an accurate steel cylinder
triblet or mandrel m, and hammered into contact
therewith with a wooden mallet. The steel mandril
diminishes in diameter at the shoulder s s, and the
brass tube is set or hammered down around this
TUBES AND PIPES—TUNGSTEN.
861
shoulder. At 1.: la is a handle or key passing through
a slot in the reduced portion of the mandrel. The
brass tube being thus arranged, it is drawn by means
of the key, through the draw-plate pp, the metal is


forcibly compressed between the mandril and the
plate, and thus becomes elongated as in wire-drawing.
A large collection of truly cylindrical triblets are re-
quired to suit various kinds of work; and for tele-
scope tubes; which slide within one another, there
must be “ a nice correspondence or strict equality of
size between the aperture of the last thaw-plate and
the diameter of the triblet for the size next larger;
and as these holes are continually wearing, it requires
good management to keep the succession in due order
by making new plates for the last draught, and adapt-
ing the old ones to the prior stages. Sometimes, for
an occasional purpose, the triblet is enlarged by leaving
a tube upon it, and drawing the work thereupon; but
this is not so well as the turned and ground surface of
the steel triblet.”1 '
Fluted tubes for pencil-cases are drawn through
ornamental plates, the mandril being usually cylindri-
cal. Joint-wire, used by silversmiths for hinges and
ioints, is a small pipe threaded upon a piece of steel
wire, and both are drawn together like a piece of
solid wire. A semicircular channel is filed half-way
in both the parts to be hinged, and short pieces of the
joint-wire are soldered in each alternately. Tubes of
small diameters may be completed at 2 or 3 draughts;
after which, the tubes have acquired their greatest
degree of hardness. The finished tube is drawn off
the triblet by putting the key through one end, and
drawing the triblet through an accurately fitting brass
collar, which thrusts off the tube.
Tubes are sometimes drawn vertically by means of
a strong chain wound on a barrel by wheels and
pinions. In Donkin’s tube drawing machine, a ver-
lical screw is used, the nut of which is turned round
by toothed wheels driven by 6 men at a Windlass.
This machine draws out cylinders for paper making,
[see PAPERJ and other machines, as large as 26%
inches in diameter, and 6%- feet long.
The method of forming lead pipes is described
under LEAD, Fig. 1285. In this case there is no
soldered edge, which is an advantage. The brass
tubes of locomotive engines are also made by casting
and drawing; they are cylindrical without and taper
within. The metal for them is cast hollow, and then
forced on a taper triblet, and drawn through an
ordinary plate. The thick end of such tubes is placed

(1) Holtzapffel, “Mechanical Manipulation,” vol.

near the fire-box, in order the better to resist the
action of the fire, and that the cinders which enter
its smaller end may readily escape at the larger.
The remarkable ductility of tin is shown in Rand’s
patent collapsable vessels for artist’s colours. Pieces
3 inches long are capable of being extended 36 inches
by drawing them through 10 draw-plates. A tube
cast l; an inch thick and 2 feet long can thus be
reduced to fith inch in thickness, and extended to
120 feet in length. This long tube was formerly cut
up into short lengths, and the ends of each length were
closed by soldering; one end with a convex disc with
a projecting screw perforated for the expulsion of the
colour. Each tube is now made complete by means
of two blows in dies adapted to the purpose. By one
blow of a screw press a thick circular disc of tin of
the external diameter of the intended vessel is
punched out, made concave and perforated in the
centre. By a second blow the blank is converted
into the finished tube. The bottom tool is a mould
with a shallow cylindrical cavity of the same diameter
as the tin blank, and terminating in a hollow screw:
the upper tool is a cylinder longer than the tube, and
with a small taper spindle of the diameter of the
hole. The cylinder is just so much smaller than the
mould as to leave an annular space equal to the
intended thickness of the tube. The tin when sub-
jected to great pressure in the contracted space within
the mould fills up the annular crevice almost instan-
taneously. The tube thus formed is released from
the mould, first by raising the cylinder, which leaves
the tube behind, and the screwed extremity of the
mould is driven up by a ram and lever from below,
(as in Fig. 1819 of RAISED Wonxs 11v METAL, of
which this may be taken as an instructive example,)
and the screwed dies being divided on their diameter
immediately fall away from the vessel. For large
tubes the hydrostatic press is used.
The formation of cast-iron pipes falls under the
general head of CASTING AND FOUNDING: this branch
of manufacture, however, has of late years received
many important ameliorations, which are carried out
under the patents of Messrs. Cochrane and Slate, at
the Woodside Iron Works near Dudley.
TUFA. Calcareous tufa is a loose porous deposit
from calcareous springs. The more solid limestone
formed in lakes and on the sides of hills, is called in
Italy imoeriin. Many of the edifices of ancient and
modern Rome are built of travertin from the quarries
of Ponte Leucano. There is also a siliceous tufa
consisting of volcanic material, either cinders or the
comminuted lavas. Pozzuolana is a tufa of this kind.
See Monrans and Cnnnnrs.
TUNGSTEN, W101. The mineral Wolfram is met
with in Cornwall, and also a native tungstate of lime.
The metal is obtained from tungstic acid, W03, by
heating it strongly and passing a stream of hydrogen
over it. It is a hard, brittle, white metal of the
density 17'41. Heated to redness in the air it takes
fire and tungstic acid is reproduced. There is an
oxide of tungsten W02, but it does not form salts
with acids. In our Inrnonuc'rour Essxr, p. xcvi,
802
TUNNEL.
an outline is given of Mr. Oxland’s method of dress-
ing tin ores which contain Wolfram. Wolfram is also
used for making tungstazfe of 161161, a pigment used
instead of white lead-
TUNNEL, an arched passage underground, con-
structed for the purpose of conducting a canal or
road on a lower level than the natural surface.
Tunnels are not new in civil engineering, for the
Romans often constructed them to avoid the incon-
venience and loss of power occasioned by conducting
a road over elevated ground. The extension of canals
led to the formation of many tunnels, [see NAVIGA-
TION, INLAND ;] the driving of the tunnel under the
bed of the Thames was a work of unparalleled dif-
ficulty; but it is to the extension of railways that we
owe the formation of tunnels under almost every
variety of circumstances which are likely to occur.
Tunnels have been formed in order to avoid the
opposition of landowners, or to give uninterrupted
passage under a road, a canal, or a river; tunnels
have been formed under towns, in order to connect
points which were not accessible by an open passage
except at an enormous cost; but in general tunnels
are formed through hills, in order to avoid the expense
of an open cutting.
Tunnelling, like mining and other subterranean
operations, does not derive much assistance from
mechanical appliances; it is performed by hard
manual labour, and is liable to unforeseen interrup-
tions, which can only be got over at a great expense
and with difficulty- Many of the old canal tunnels
were executed at 41. per. lineal yard; some of our
railway tunnels have cost upwards of 1301. per lineal
yard. For example, Kilsby tunnel on the London and
North Western line, which was contracted for at 4.01.
per yard, actually cost 1331., (the contract was let for
99,0001. and the actual cost was upwards of 320,0001.)
in consequence of the intersection of a quicksand
which the trial borings had escaped. Pumps had to
be erected to drain the sand, which extended through
1150 yards of the length of the tunnel, and for 9 months
2,000 gallons of water were pumped up. The Box
tunnel on the Great Western Railway cost upwards
of 1001. per lineal yard. Bletchingley tunnel on the
South Eastern Railway, 721. per yard: Saltwood
tunnel on the same line, 1181. per yard. In the latter
work the tunnel intersected a great body of water in
the lower green sand, so that a heading or adit had to
be made quite through the hill on a level with the
bottom of the tunnel, in which the water was collected
and drained off. The cost of the Thames tunnel was
1,2001. per yard, but this must be regarded as an
exceptional case; moreover it consists of 2 arches,
and is in fact a double tunnel. The large sums which
the above-named railway tunnels cost, ought also to
be considered as exceptional; for where no accidents
from water, quicksands, &c. occur, the cost is much
less. For tunnelling at the ordinary dimensions in
sandstone-rock, which is easy to excavate, and will
stand without any lining of brick or masom'y, the cost
may not exceed 201. per yard; but in loose bad
ground, a lining of masonry or of brick-work 27 _

inches thick may be required throughout the tunnel,
and in such case the cost may be from 1001. to 14.01.
per yard. Provided the stone work freely, rocky
strata are generally the cheapest, on account of the
absence of lining and the saving of labour by the use
of . gunpowder. On the Glasgow, Paisley, and
Greenock railway, 314.1 tons of gunpowder were con-
sumed in a length of 2,300 yards in hard whinstone,
some veins of which were so hard that the rate of
progress at each face of the excavation varied from
3 feet 6 inches to 6 inches per diem. Tough clay is
also very difiicult to remove: and the hatchet and
cross-cut saw answer the purpose best. The Prim-
rose I-Iill tunnel on the North Western line was
excavated with great precaution, on account of the
known shifting nature of the moist clay: the excava-
tion was not allowed to be more than 9 feet in
advance of the brick-work, and the clay was supported
by very strong timbering, until the arches were com-
plete. The pressure of the clay was, however, so
great as to squeeze the mortar from the joints of the
brickwork, and to bring the inner edges of the bricks
into contact. The bricks were thus being ground to
dust, and the dimensions of the tunnel were insensibl y
but irresistibly contracting. The difficulty was over-
come by making a lining 27 inches thick of hard
bricks, laid in Roman cement, which, by setting hard
before the pressure became sufficient to force the
bricks into actual contact, thus enabled the whole
surface of each brick, instead of its edge, to resist
the pressure.
Tunnels excavated in chalk are often impeded by
faults or cavities full of wet gravel or sand, and the
semifluid matter escapes from them as soonas they
are cut into. In the Vl'atford tunnel on the North
Western Railway, which passes through the upper
chalk formation, where it is covered with a thick irre-
gular bed of gravel, fissures occur in the chalk, to the
depth of 100 feet, filled with gravel, which, on being
worked into, is described as rushing down “ with such
violence as to plough the walls of the tunnel as if
bullets had been shot against it.” The large venti-
lating shaft near the centre of the tunnel occupies the
site of one of these cavities.
But of all the materials to work in, loose, running
sand is the most difiicult. In the tunnel on the
Leicester and Swannington railway, the engineer
encountered 500 yards of such sand, so that he had
to construct a wooden tunnel to support the soil
while the brick-work was being executed. When
water occurs with loose soil the difficulties are further
increased.
The Box tunnel, to which we have ah'eady referred,
although excavated in rock, may be quoted as an ex-
ample of difficult engineering. This tunnel, which is
3,123 yards, or a little over 1% miles in length, inter-
sects oolite rock, forest marble, and has marl with
fullers’-earth. Eleven principal shafts, about 25 feet
in diameter, and 41 intermediate shafts 12% feet in
diameter, were sunk for the purpose of carrying on the
works. The section of the tunnel is 27 feet 6 inches
wide at the springing’ of the invert, and 30 feet wide
TU-N N EL.
863
at a height of 7 feet 3 inches above this: the clear
height, above the rails, 25 feet. These dimensions,
however, are not strictly followed in the greater por-
tion of the tunnel, which is constructed by mere
excavation, since the clearing away of loose stone,
and the securing of solid surfaces, would not admit
of it. In those parts where brick-work is used, the
sides are 7 half-brick rings in thickness, the arch 6,
and the invert it. During the construction the nu-
merous fissures of the rock poured such a constant
flow of water into the works, that a most extensive
system of pumping had to be adopted; and so com-
pletely had the water gained over the steam-pump,
that the works had to be suspended from November
1837 to July 1838: for not only was the completed
portion of the tunnel filled with water, but also a
height of 56 feet in the shafts. A second pump,
worked by a steam-engine of 50~horse power, was
applied, and allowed the works to be continued.
About 32,000 hogsheads of water per day were, for
some time, pumped up.
The method of tunnelling depends greatly on the
kind of material to be excavated. A number of small
borings is first made along the proposed line, and if
these are satisfactory, shafts, at least 41 feet in diame-
ter, are sunk along the line to the extreme depth of
the tunnel: the quantity of water that appears in
these, in a given time, will show how much draining-
power is required. These trial-shafts should be so
situated as to be convertible into working-shafts ; or
they may be used as ventilating-shafts. In certain
cases, however, as in tunnelling near the side of a hill,
horizontal galleries may be driven from the face of the
hill to the line of the tunnel, and the excavated earth
be removed through them. The double tunnel, through
the Shakspere Cliff on the South Eastern Railway,
was constructed in this way. Tunnels are also some-
times formed by means of an open cutting, and are
afterwards covered in. Such are called open tunnels,
and they are made where the object is rather to avoid
the permanent severance of lands than to penetrate
ground which is too elevated for an open cutting.
The short tunnel at Kensall Green was formed in this
way.
The usual plan, however, is by means of vertical
shafts, and the driving of horizontal headings: and as
the tunnel must, for obvious reasons, except in cer-
tain rare exceptional cases, be straight, and the works
are proceeding not only at both ends, but also on two
faces at the bottom of each shaft, it becomes amattcr
of paramount importance that the centre line he care-
fully ranged; for, by its means, the works below are
corrected and ultimately made to fit together or meet
into each other. The centre line is ranged by means
of a transit instrument placed in a temporary building
erected on some elevated spot of ground, as nearly
over the middle of the tunnel as possible, so as to
command a view of every shaft on the work, and at
the same time be raised above the machinery and
timber about the shafts, as well as the heaps of earth
from the excavations. The transit instrument is
supported on a brick pier, insulated from the building

in order to prevent vibration. Fig. 2183 is a section
of the Saltwood Observatory in the direction of the
tunnel on the South Eastern Railway. The brick
pier is 30 feet high: it is
placed over the centre line
of the tunnel, and on the
top is a flat stone to which
the iron stand of the tran-
sit is screwed down. The
building was of timber : the
upper part, or observatory-
room, was enclosed with
quartering and feather-
edged boards. The ascent
was by steps from below i ’
through a trap-door in the ' l .
floor, and the floor was , r j].
trimmed so as not to touch


the brick pier by 5 or 6 in- \ /
ches. Narrow openings i I
were made in the side “ -s
of the observatory-room,
through which the observer l l ‘I .
might look each way for ' {ft-r
the ranging of the lines:
these holes were closed //
with small sliding shutters, 7”? / ,
so that one or more could /
be opened at a time. The
building was surmounted by a two~armed telegraph,
by means of which signals could be given for the
ranging lines to be moved to the right or to the
left, and when the line was found to be correct,
both arms were extended, thus denoting that the
line was to be fixed in its position as thus found.
The transit instrument consists of a telescope with
an axis at right angles to its length, supported on a
cast-iron stand. It is a standard instrument in every
astronomical observatory, “where it is adjusted to
describe or define a vertical circle passing from the
north to the south points of the horizon, through the
zenith of the place, and is the best means of observing
the passage of the celestial bodies across the plane of
the meridian, from which time is correctly derived:
hence its name, lmrzsz'l instrument, and thus .em-
ployed, it may not inappropriately be called the lzaml
which points to the time as shown by that unerring
dial, the starry heavens. The same construction which
renders it the instrument best adapted to trace a ver—
tical plane for astronomical purposes, makes it equally
so to set out a right line on the surface of the earth;
or, our problem more properly is—to find any number
of points in a straight line, connecting two given dis»
tant points, the instrument to be situated also between
the given distant points. The line thus connecting
the distant points is the base of a vertical plane of
small extent.” 1 To do this, the telescope 'r 'r is made
to revolve vertically on a horizontal axis A A, the


Fig. 2183.

(l) “ Practical Tunnelling, &c., as exemplified by the parti-
culars of Blechingly and Saltwood Tunnels.” By P. W. Sirnms,
8:c., C.E. 4to. London, 1844.
86.4,
TUNNEL.
pivots of which are supported by the upright arms I I
of the iron stand. It is necessary for the correct
performance of the instrument that the optical axis
of the telescope, or line of collimation, be precisely
at right angles to the horizontal axis about which it
revolves; and also that the extremities or pivots of
the horizontal axis, where they rest in their bearings
on the iron stand, be precisely level with each other.
The telescope (as in the telescopes of theodolites and
levels) is furnished with cross wires, and the intersec-
tion of the centre wires with each other represents
the line of collimation when the instrument is in
proper adjustment. To obtain distinct vision of the
cross-wires, the eye-piece E is moved in or out by
means of the screw 8, which moves a rack and pinion.
Much care is required in the adjustment of the eye-
piece to the wires, and of the wires to the focus of the
object glass, so as to avoid parallax, or an apparent
motion between the object viewed and the wires of
the telescope, which is detected by moving the eye
up or down, or sideways, while looking through the
telescope. In order to support the telescope without
bending, the horizontal axis is made of 2 cones AA,




V
I \
I §
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um ‘i
Fig. 2184. TRANSIT INSTRUMENT.
the bases of which are connected together and to the
telescope by means of a sphere 8, through which the
telescope appears to pass. The apex of each cone
has a steel or bell-metal cylindrical pivot turned and
ground upon the axis as true as possible, for, unless
they are true, the instrument cannot describe a verti-
cal plane. The pivots work in Y’s at the top of the
upright arms II. The spirit-level ll, placed across
the instrument, allows the axis to be adjusted hori-
zontal,'in which position it is evident that the tele-
scope, or line of collimation, whether elevated or
depressed, or turned completely over and pointed in
the opposite direction, must continue in the same
vertical plane. The cross-wires of the telescope
usually consist of a single spider’s-thread ; which,
while being extremely fine, is perfectly opaque, and

does not become fringed with light alofig its edges,
as is the case with artificial substances. By day, the
cross-wires are sufficiently visible, but when using the
instrument underground, or by night, to range a dis-
tant light, the wires would not be visible, and the
instrument would be useless. To get over this diffi-
culty, therefore, one of the pivots is perforated through
the cone A and the sphere s, and the light from a
small lantern, adapted to the top of the stand, passes
through such perforation, and falling on a diagonal
reflector in the sphere, is thence thrown upon the
focus of the instrument, where the wires are fixed, near
the eye-piece. The reflector is also perforated to
allow the passage of the cone of rays in their conver-
gence from the object-glass to the focus.
Long before the commencement of working opera-
tions the direction of the centre line of the intended
tunnel must be known nearly and staked out. The
observatory is then erected, and a permanent mark set
up at a distance from each end of the tunnel, precisely
in the intended line for future reference and the
occasional adjustment of the transit. At Bletehingl y
tunnel Mr. Simms caused to be erected 2 brick piers
about 5 feet high, at the distance of full 2 miles from
each end of the tunnel; such a distance secures
accuracy in the adjustment of the transit, but as in
foggy weather they cannot be seen, similar marks
should be set up at shorter‘ distances. All these
piers were painted black with white lines from 2 to 6
inches wide, according to their distances, to denote the
precise line with which the centre of the tunnel was
to coincide throughout its whole length. A straight
line from the centre of one of the distant marks to
the centre of the other in the opposite direction
should pass through the telescope when set for use
so as to coincide with the line of collimation.
The transit being thus properly fixed, and a distant
mark selected in the line of the tunnel, and a fixed
spot placed at a considerable distance as a point of
adjustment for the line of direction, the intermediate
marks for the positions of the shafts may then be
correctly set out ; and when these shafts have beer
sunk, the points as determined by the transit instru-
ment are carried down by means of iron plummets
carefully suspended, and let down in buckets of water
or cups of mercury to check vibration. A second
transit instrument is then mounted at the bottom
of each shaft in succession as far from the plumb-line-
as possible, and the intersection of the vertical wires
in the transit with the plumb-line will evidently give
the means for setting out the work correctly, and
forming junctions between the several workings or
shifts. In the Box tunnel, in a length between two
shafts of 1,520 feet and with a slope of 1 in 100 the
junction of the two shifts was perfect as to level and
did not differ more than 1%; inch in any place at
the sides.
The working shafts are of course made sufliciently
large to lower men and materials, for raising the earth
or rock excavated, for fixing pumps, 850. These shafts
are generally from 8 ,to 10 feet in internal diameter;
they are lined with brick usually 9 inches thick,
TUNNEIT
865
and are curved 8 to 10 feet above the surface of
the ground, and are finished with a stone coping.
In sinking a shaft the earth is first excavated until
it begins to appear too weak to stand by itself. A





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, .- =r~ '\ h ‘v- f
/ I. _ l'fakzff-f ,iihzfiliiftl ',/%//I
we .5 /, ,
,ihii‘ii: v: IL. ‘ n __r // %
I '" 7'12??? . ,f"‘1"\’=\ --.: ,- I I I I
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/ 1. . ,3» , J” y
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Fig. 2185. SINKING- a SHAFT.
wooden curb or ring (shown in the section, Fig. 2185),
as wide as the intended brick lining, is then placed
at the bottom of the excavation, and on this the brick-
work BB is laid. This part of the shaft is often not
more than half a" brick, or 41% inches thick. When
completed, the excavation is carried down even with
the inner surface of the brick-work, so that the earth
beneath the curb serves as a support, and diagonal
props of timber (as shown in the figure) may be used
if necessary. WV hen the excavation has been carried
down so far below'the curb that the ground again
appears weak, a second curb is inserted in a groove
cut for the purpose, and the ground between the
2 curbs is divided into 4, 6, or 8 vertical masses,
one or two of which are removed to a depth equal to
the thickness of the brick-work. The wall is then
built up in the spaces thus made for it; one or two
other vertical portions are removed and built in, and
so on until the lining is completed. By this nie-
thod of underpinning, as it is called, the shaft is
carried down to the full depth. The working shafts
and the air shafts rest on curbs of cast-iron fitted into
the crown of the tunnel, and forming level bases for
them. But when the shaft has been sunk to the re-
quired depth, the brickwork must be supported in
some way, before any excavation for the tunnel can
be made below it. This support is made either by
placing horizontal timbers below the brickwork, or
by suspending the brickwork by means of iron rods,
secured to timbers resting on the surface of the
ground. The air shafts are similar to the working
shafts, only of less diameter, 3 feet being gene-
rally sufficient. These are not sunk at a less dis-
tance that 50 yards from the working shafts. In
some tunnels a large oblong opening, called an eye, is
introduced, instead of ventilating shafts. In the
Bishopton tunnel there is an eye 300 feet long.
ing the materials, and in drawing water up the shafts,
unless large pumps are employed with steam-power
to work them.
The greater the number of working shafts the more
men can be employed, and the quicker will the work
be done. Some of the old canal tunnels occupied as
many years in their construction as some of the
modern railway tunnels have occupied months. Thus
the Harecastle tunnel on the Trent and Mersey canal
was 11 years in being formed under Brindley. It is
2,880 yards long, 12 feet wide and 9 feet high. It
is lined with a semicircular brick arch, and was com-
pleted for the small sum of 3!. 108. 8d. per yard.
The new tunnel required by the increased traffic on the
canal was commenced by Telford in1822 ; it is 2,926
yards long, 14- feet wide, and 16 feet high, with an
iron towing path, supported so as to allow the water
to play freely beneath it. This tunnel, (a cross
section of which is given under NAVIGATION INLAND,
Fig. M99, and the centering used in its construction
in Fig. 1500,) notwithstanding its increased dimen-
sions, was completed in less than 3 years. Many
railway tunnels of superior magnitude have been
completed in much less time, on account of the large
number of working shafts. Thus the Watford tunnel,
75 chains long, was worked with 6 shafts of 8 feet
diameter, and an air shaft was constructed at the
distance of 50 yards on each side of each working
shaft.
When the working shafts have been carried down
to their full depth, narrow headings, or drift ways
Fig. 2186, or DD, Figs.
2187, 2188, from 6 to
12 or 15 feet in length,
3 or 4! feet in width, and
high enough for a man
to work in, are excavated
v .s “\\ \\\ \\\\.\1_\ XXV“
\\ \~


along the level of the \\ \
upper or lower part of the §‘\ ‘.
tunnel, or such a drift ‘mi
may be formed through- \t? i. I.
out the whole length of \

s l
the tunnel before any i ' ‘
part is opened out to the Ii . i I "
full size. The kind of V?”- "flt ‘4
strata to be worked and
the amount of drainage
required are thus ascer-
tained, and moreover the continuous heading serves
as an adit or drain. Contracts for tunnelling are
often not let until such a heading has been formed by
the Company. The top of the heading should be so
much above the intended sofiit of the tunnel-arch as to
admit the thickness of the brick-work besides the
bars of timber and boarding by which the roof of the
heading is supported, also allowing several inches for
the settlement of the timber, which always occurs in
excavations before the brick-work can be got in.
Unless this allowance be made, the brick-work will be
forced down, and can only be raised by removing the
superincumbent earth piecemeal and at great cost.
Fig. 2186.

Horse-gins are usually employed in raising and lower-
voL. II.
Bars 6 6, Figs. 2187, 2188, and polings pp, and pack-
3 K
806
TUNNEL.
ing boards are introduced as required. “ The head—
ing is extended on either side by cutting first narrow
gaps horizontally, or rather dipping downwards in di-
rections following the intended form of the tunnel-
arch. Into these gaps crown bars are laid lengthwise
and supported upon props; and poling boards are put
in between them, to retain the earth at the sides of
the excavation when extended. When the heading has
thus been widened by excavating right and left, and a
sufficient length cleared, the centerings are fixed and
the brickwork is commenced. As this proceeds the
. is; it
\\\
=.
e
l
titfit:
>
i
I


Fig. 2187. cnoss-ssc'rron on runner“

Fig. 2188.
LONGITUDINAL SECTION.
earth is carefully rammed behind it, and all vacancies
filled up, to prevent any subsequent settlement of the
surrounding earth upon it. The crown bars which were
inserted in the heading and always during the excava-
tions, are not always removed. If they can be drawn
forward as the heading advances, without disturbing

the adjacent ground, and the spaces filled up with
broken stone, or other suitable material, no objection
can arise; but otherwise they should be allowed to
remain and be built in. The whole of the operations
require careful regulation, so that none of them shall
advance too rapidly for those which follow. The
contractors are therefore usually restricted to carry
the excavation not more than 6 or 8 feet in advance
of the brick-work, or less, if so directed by the
engineer, should any change occur in the strata which
he thinks may require such precaution. When the
faces of two contiguous excavations approach within
about 50 yards of each other, a heading should be
driven quite through the intervening ground, and the
workings joined before the whole excavation and
brick-work are proceeded with.”1
The sides of the tunnel are curved or battered, the
amount of curvature as well as the form of the arched
roof depending greatly on the kind of ground to be
supported. When, as in the case of the Primrose-hill
tunnel already referred to, and shown in section, Fig.
2189, a shifting clay is to be supported, such a material
! will press nearly equally in every direction, and the
tunnel will very properly be made to approach the
circular form. The invert I, which is formed of 3 con-
centric half-brick rings, is a curve of 25 feet radius:
the arch an, of at half-brick rings, is struck with a radius
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SECTION OF PRIMROSE-HILL TUNNEL.
Fig. 2189.
of 11 feet 9 inches, the sides are arcs of 27 feet 6
inches radius. The brick lining, as already stated, had
to be increased from 18 to 27 inches. The width of
the tunnel is 21 feet 5 inches at the springing of the
invert, and 241 feet 8 inches at the widest part. The
clear height is 21 feet 8 inches, a depth of 3 feet 41in-
ches being occupied by the ballasting B .B, drain d, &c.2
The invert and the arch should be built in half-brick
rings, and the proper number of bricks put into each
ring, to ensure uniform bearing. Each ring should

(1) Dempsey’s “ Practical Railway Engineer.” 4to. London,
1847.
(2) Further particulars respecting the design and construction
of this and other tunnels will be found in “ Railway Practice,”
by S. 0. Brass, 0.13. &c. 4to. London, 1837. A second series
was published in 1840.
TUNNEL.
867
usually contain 5 more bricks than the ring imme-
diately within it. The side walls may be built in
English bond, or alternate courses of headers and
stretchers. The best bricks should be used, and if
the form of the tunnel require it the bricks should be
moulded of a taper shape. Every brick should be
bedded with a wooden mallet, and the joints if in
mortar well flushed up. The brick drain should be
built in Roman cement, with the joints left open for
about half an inch to admit water from the ballasting.
Water should be excluded as much as possible during
the building of the tunnel and shafts, by puddling with
clay. It will, however, often penetrate through the
by lining the roof with sheet zinc. The Thames
tunnel has an interior lining of cement, with channels
in the brick-work behind it for the passage of water.
The ballasting for the roadway should not be such as
will retain water; it should be well rammed down,
and the blocks or sleepers be carefully bedded, and, as
an additional security, it is usual to place the sleepers
or points of support closer together in tunnels than on
other parts of the line.
The following table presents some of the most
important particulars respecting a few remarkable
tunnels :-—





59.: . =1 .
=-* m g n
It‘ s 2 2 . s E.” 'd ‘5% 1.1 7-1 E Q‘ '&
Name. Purpose to which applied. 2 E m g ‘I: ‘*5 a. g‘ g g
o 0.1 g $ _ o .... tn 0 ‘a
a E =1 2 I! m i‘; 8 ZS =8 0
s a e r s 2 2 2 s a 2
C 1 d ft d ft. m. ft. 1n.lit.1n. )ards. C} 1k d B £ £
ana an a erwar s _ , I . . 1a an rick-
Thames and Medway' North Kent Railway} 39 0 35 6 1 2 579°‘) tuller’s earth} work 180° W- T- Clarke-
. ,s , , , . London 0111' -
Islmgton Tunnel....... Regents Canal ....... .. 21 6 20 0 1 o 900 { formatiomy} ditto .. 1812 Morgan.
Harecastle Tunnel..... Tetney Haven Canal. 16 ' 2 l7 ' 0 l ' 2 2,9625 Various strata. ditto 112,681 38% 1827 Telford.
Watford Tunnel......... 26 - 6 27-0 1~e 1,830 Chalk. ditto 133s R.Stephenson.
Box Tunnel...............{Gégi‘rt western Rail‘ as - o 36 - o 2 - a 3,123 Freestone. ditto 183SB1-unel.
Littleborough Tunnel hiagéggefigflwayff 27 - 6 27-0 1-102, 2,860 Various strata. ditto 251,000 as 1841G.Stephenson.
Thames Tunnel Foot Passengers....... 22 ' 3 37 ' 6 2 ' 6 400 London clay. ditto 454,714 1,137 1842 Brunel.
Blechingly Tunnel..... so - o 30 - 0 1-105 1,324 Shale. ditto 95,237 71 1842 W. Cubitt.
Saltwood Tunnel........ Ditto ................ .. 3o - a so - 0 2 -3 934 {Lwgngl'een ditto 112,542 118 1843 ditto.
' l



The Thames Tunnel is well known, and has been
often described in a popular manner; but as an
article on tunnels would not be considered complete
without some account of it, we will notice very
briefly its history and construction.1 It was proposed
as early as the year 1798, by Ralph Dodd, the
engineer, to open a passage under the Thames, at
Gravesend, so as to connect it with the Essex shore.
In 1804, Chapman proposed a tunnel at Rotherhithe,
and in 1807 a commencement was made, by sinking
a shaft at a distance of 315 feet from the river; but
the constant influx of sand and water defeated the
project. Trevithick was then engaged to drive a way
under the bed of the river, and he succeeded in
forming a drift 5 feet in height, 2 feet 6 inches
in breadth at the top, and 3 feet at the bottom, for
a distance of 1,026 feet under the river; but the
water broke in upon the workmen, and the project
was abandoned until, in 1823, a Gompany was formed
to carry into effect the plans submitted by Mr. after-
wards Sir Mark Isambard Brunel, which may be
briefly stated as follows :—--A shaft, 50 feet in
external diameter, the walls being 3 feet in thickness,
was sunk by first driving 24: piles, with a shoulder

(1) There is a very good popular account of the Thames
Tunnel in Knight's London, vol. iii. The fullest, and. in every
respect the best account, is a memoir by Mr. Law, in Weale’s
“ Quarterly Papers on Engineering.” An abstract of this Ine-
rnoir is given in Weale’s “ London in 1851 ;” and also in MI. Law’s
“ Rudiments of Civil Engineering,” contained in Weale’s Rudi-
mentary Series.
projecting, on the side of each, within the circle
intended to receive it: on these was laid the timber
curb, which also partly rested on one of cast-iron, the
latter having a sharp cutting edge, which entered the
ground; through this curb were passed 418 wrought-
iron bolts, 2 inches in diameter, to a height of ‘15
feet, equal to the top of the intended shaft. On this
curb the shaft was built with bricks laid in cement,
and as the work proceeded, it was bound together
by 26 circular timber hoops 2- inch thick. When the
brickwork was completed, another timber curb was
placed on the top, and through this the long iron
bolts were passed, and their ends being formed into
screws, nuts were put on and screwed up, so as to
make the shaft as it were one mass. ’When the
cement was sufficiently hard, the earth within the
shaft was excavated; 16 of the piles on which the
shaft rested were driven in pairs opposite each other,
half an inch at a time, and then the whole gradually
sunk, carrying with it the other 8 piles. The 16
piles were next drawn out by opening the ground at
the back, when the whole weight of the brick shaft,
==QlO tons, then rested on the 8 piles, and these
were afterwards drawn when a bed of gravel had
been reached. The shaft was thus passed through a
bed of wet sand and gravel, 26 feet deep. At the
depth of 410 feet, the shaft became earth bound, and
it was necessary to complete it by underpinning the
brickwork, i.e. building it downwards as the excava-

ltl-Ofl was carried down. The loose nature of the
brick-work, an inconvenience which has been remedied
3 K 2
868
TUNNEL.
ground rendered this a matter of dilficulty. This
lower portion of the wall was increased in thickness
to 41 feet, and was built of rag-stone, laid in mortar
composed of cement and lime, and lined with 2
courses of brick laid in cement. At the depth of
80 feet an invert was formed, and in the centre a
smaller shaft, 25 feet in diameter, was sunk still
deeper, to serve as a well for water from the drains
of the tunnel; but at the depth of about 80 feet
from the surface, the ground suddenly gave way, and
a quantity of sand and water was blown up. The
excavation for the tunnel was 38 feet wide, and 22
feet 6 inches high, and in order to leave a sufficient
depth of ground in the middle of the river above the
brickwork, the tunnel was formed with a declivity of
2 feet 3 inches in 100 feet. The ground above was
supported while the excavation was going on by a
s/tz'elrl, consisting of 12 massive iron frames, placed
side by side, and capable of being slid forward,
independently of each other, for a short distance, by
means of screws abutting against the end of the
completed brickwork, which followed closely on the
excavation. The shield was supported on flat soles,
capable of being easily moved forward; the top and
sides were also closed in by flat plates, which
were supported by massive framing, and also fitted
close to the brickwork, by which means the soft
earth was prevented from falling in. Each frame
of the shield consisted of 3 stories, with a cell in
each, in which one man could work; the front of
each cell was protected by a series of narrow poling
boards, each of which was held in its place by an
arrangement which allowed it to be fixed in avertical
line even with the face of the shield, or a few inches
in advance thereof. Each miner began operations by
removing the upper poling board in his division of the
shield, and excavating the small portion of earth thus
exposed to the depth of about 6 inches; he then re;
placed the poling-board, and caused it to press, by
means of jack-screws, against the face of the ex-
cavation; he next removed a second board, where-
by afresh portion of earth was exposed and excavated
as before. When all the poling boards in one frame
of the shield had thus been advanced 6 inches, the
frame itself was moved forward, and the same series
of operations repeated. The frames of the shield
were thus alternately moved forward, slowly and with
great caution, the brickwork following close upon the
shield, and enclosing two arched passages, 26 feet
4! inches in height from the invert to the crown of the
arch, and 13 feet 9 inches span at the springing of
the arch. This shield was so damaged in the course
of the work that it had to be taken down, and a new
one raised. The new shield will be described at the
end of this article. The arch, the invert and the
curved side walls are laid in concentric rings, either a
whole brick or a half brick in thickness, each ring pre-
senting a plain face, no bond being employed between
the successive rings. The tunnel is built with the
hardest picked stock bricks; the first or inner ring
of the arch is laid in pure cement, and the other
portions of the work in half cement, and half clean

sharp sand. The bricks for the semi-circular portion
of the arch were moulded to the true wedge form, so
that the bricks radiated with parallel joints between
them. The total thickness of the brickwork at the
thinnest points where the enclosed arches approach
nearest to the boundary of the rectangular mass of
brickwork, is 3 feet. A solid wall, 3 feet 6 inches thick
at the top, and 41 feet at the bottom, was constructed
between the arches; small transverse arches being
afterwards cut through it at intervals to form open-
ings from one tunnel to the other. The whole of
the brickwork is laid in Roman cement, and each
archway is to be finished with a lining of cement, a
carriage-road, and a narrow footpath adjoining the
central wall. Only one archway, however, has been
thus completed. A brick drain is laid down from the
centre or lowest point of the tunnel, to the Bother-
hithe shaft, by means of which any water that per-
colates through may be removed. The inclination of
the roadway conducts the water from the other half
of the tunnel into the drain.
The excavation of the tunnel was commenced in
January, 1826, in a stratum of clay; but in a few
weeks much difficulty was experienced, in consequence
of meeting with a break, or fault, filled with sand
and gravel. This obstacle, however, was passed
through in 32 days, and by the end of the first year,
350 feet of the tunnel were completed. Moist clay
was occasionally forced through the shield. Cavities
in the bed of the river had to be frequently filled
with bags of clay, to prevent the water from break-
ing through. In examining the bed of the river, in
a diving bell, a shovel and a hammer were left in the
river, and these were afterwards found in a mass of
loose earth which broke into the tunnel. The works
were continued until the 12th May, 1827, when the
river broke in with such rapidity and violence, that
Mr. Beamish, the engineer on duty, and the men
under him, narrowly escaped being overwhelmed. On
examining the bed of the river in a diving hell, it
was found that about 25,000 cubic feet of earth had
been displaced. Tarpaulings were put down over the
hole, and filled up with bags of clay and gravel. The
tunnel was then pumped dry, and was entered on the
27th June, when the finished part was found to be
uninjured. It was not until the end of September
that the shield was again advanced; but the progress
was very slow; the influx of water was very copious,
and on one occasion it amounted, for several hours,
to 1,200 gallons per minute. By the middle of Ja-
nuary, 1828, another 50 feet had been added to the
tunnel, making the length of the finished portion 605
feet; when on the 12th the river burst in so suddenly,
and the tunnel filled so rapidly, that of seven persons
in the works, Mr. Brunei alone escaped; he was
hurried along by the flood, and. was carried up the
shaft by the rush of water. The hole in the bed of
the river was filled up, and on the 12th of April the
shield was again entered. By this time, however,
the funds of the company were nearly exhausted, and
the works were suspended. In order to render the
tunnel as secure as possible during the suspension of
TUNNEL.
869
the works, a solid wall was built at the unfinished
end of the arches, so as completely to shut out the
river. One arch of the finished portion was lighted
with gas, and opened to the public; and it proved,
for a time, a very attractive exhibition. After
repeated applications, Government consented to ad-
vance money for the completion of the tunnel. A
new shield was substituted for the one which was
injured by the irruption, and from that time, until
1812, the work slowly progressed at the rate of a few
inches per week. Three more irruptions had taken
place, in one of which a miner lost his life; the same
remedy was applied as before, and the bed of the
river over the shield was constantly watched, sound-
ings taken at every tide, and bags of clay and gravel
thrown in when any depression was discovered. As
the tunnel approached the VVapping shore, a shaft
was commenced on that side of the river, and the
further progress of the tunnel stopped until the shaft
was completed, as it was supposed that some settle-
ment in the tunnel might be produced ‘during the
sinking of the shaft if brought too close to each
other. The shaft was made 55 feet in external
diameter at the bottom, and 58 at the top, this taper
form being given to prevent its becoming earth-
bound. On the 13th August, 1841, Sir M. I. Brunel
passed from this shaft into the tunnel along a small
driftway. By the latter end of November, the middle
frames of the shield had touched the brickwork of the
shaft, through which it was passed in the same
manner as it had passed through the ground. The
brickwork of the tunnel was made good to that of
the shaft, and on Lady Day, 18413, the tunnel was
opened for foot passengers. The approaches for
carriages, which are proposed to be by spiral roads,
formed round the sides of shafts, or circular excava-
tions, 200 feet in diameter, have not been constructed.
The tunnel is 1,200 feet long between the two
shafts. The total cost of the tunnel, up to the pre-
sent time, is 454,71411, of which 180,000Z. was
subscribed by the original shareholders, or was raised
upon debentures, and the remainder was advanced by
the Exchequer Loan Commissioners. To complete
the carriage descents, or approaches, would require a
further sum of 180,000L, thus making the total cost
of the tunnel 6811371411., or about half the cost of
Waterloo or London Bridge. The toll is one pemiy for
each person, and the yearly receipts from this source,
and from rents (the cross arches being fitted up with
stalls for the sale of toys, 850.), do not amount to
5,000l., a sum scarcely sufficient to cover the neces-
sary expenditure, in consequence of the constant in-
flux of land springs.
We will conclude this article with a description of
the new shield above referred to.
The junction of the shield was to keep a temporary
lining of planks or iron plates pressed out in all
directions against the whole unfinished part of the
excavation, until this lining could be replaced by the
advance of the permanent one of brickwork. The
brickwork was always completed up to about 9
feet from the extreme end or face that was being

excavated, so that the surface to be lined in this
temporary manner consisted of 5 planes, the front or
end plane, containing about 850 square feet, the two
sides, for a length of 9 feet, containing about 220
feet each, and an equal length of the roof and floor
of the excavation containing about 350 each. The
front plane, of course, was composed of numerous
small pieces or polings, so supported that each might
be removed singly without disturbing its neighbours,
and replaced and pressed further forward after the
removal of a small thickness of the ground before it.
A single poling measured only about 37 inches by 6,
placed horizontally, so that there were 12 in the
width of the work, and 4A: in its height, or 528 in
all; and each was only kept open at one time long
enough to excavate its own thickness, which was
3 inches. Now the problem to be accomplished was,
without interfering with this capability of being
singly removed, to afford them all equable support
or resistance, as well as to every part of the other
four lining planes, above, below, or on each side,—
that is, to receive separately the inward pressure of
every small piece thereof, and transmit it all to the
solid face of the brickwork behind, (this face being
interrupted by two oval voids of 1'7 feet by 14:, form-
ing the double tunnel,) and this without blocking up
the space in which the miners had to work; and
further, in such a way that the pieces finally abutting
against the brickwork might have the pressure alter-
nately transferred from some of them to others, to
leave every part of that brick face successively free
to be built forward; and lastly, so that the whole
mass of this machinery might be progressively ad-
vanced, as the excavation proceeded in front, and
fresh additions were made to the masonry behind.
The whole movable structure thus occupying a
space 37 feet 6 inches long or broad, across the
tunnel, 9 feet thick or deep in the direction of its
length, and 22 feet 8 inches high, was exclusively
of iron, chiefly cast, and forming 12 independent
portions called flames, placed side by side like
volumes in a library, in order that six alternate ones
(numbered 1, 3, 5, 850.) might be released from
pressure, and shifted forward, while the other six
were transmitting the whole pressure to the brick-
work behind, from all the polings, both before them-
selves and before their neighbours, which in their
turn furnished all the resistance when these other
six were being advanced. Both the abutment or
horizontal support from the brickwork, and means
of pushing forward each frame, were afforded by
large screw-jacks, two for each frame, seen at ff,
Fig. 2191, applying themselves by ball and socket-
heads, and broad hands It it against the brickwork,
one above and the other below the mouths of the
archways. Of course these, which were called the top
and bottom abut/nent’ screws, could be at any time
removed from those six frames that were not support-
ing polings, and thus the brickwork was continued
forward by successive vertical slices or courses, either
of a brick’s thickness 3 inches, a brick’s width, 4%
inches, or a brick’s length, 9 inches; but most com-
870
TU N NEL.
monly of this last extent, as shown in the figure.
There is no more connexion or bond between these
courses or additions than between the horizontal ones
composing an ordinary building; and the two arches
in each were turned upon the same two narrow bits
of centering (one seen at 2222), which were carried
through the whole work, being lowered for an ad-
vance by the apparatus to a: y, resting on a stage
thrown across at the level of their springing, on the
stone salient courses B B.
Fig. 2190.
The absence of any longitudinal bond is a great
disadvantage, rendering the whole like a tube made
up of thin flat rings, only cemented together. This
mode of building also rendered it necessary to carry
on the wall between the tunnels quite solid, and after-
wards 0212.‘ our.‘ the cross archways that seemed ne-
cessary for convenience, and to moderate the oppres-
sive effect of so long a passage unvaried.


ELEVATION 0!‘ THE 3 LEFT HKND FRAMES OF THE SHIELD.

Of the 12 frames thus independently spanning the
tunnel’s end from top to bottom, each might be con~
sidered a kind of vertical bridge, or pair of parallel
beams or joists, for if the reader turn the figure
round with the polings dd upwards, the whole re-
sembles a deep perforated iron beam or bridge, rest-
ing by its ends on the two pillars f f, and hearing by
the numerous little pillars 666, &c., the ends of the
poling-boards d d d, which span across from one side
of the frame to the other, as the planks of a foot
bridge do from one to the other of its two
beams or bearers. Now as beams or bridge
bearers of this kind, in iron, are often made
in three lengths, and the two end pieces sloped
off to a less depth than the middle piece, so
here the frame will be seen to consist of three
parts in height, firmly bolted together, and the
upper and lower ones sloped off to save ma-
terial. They were called 10./ves, being in fact
skeletons of boxes, or boxes open on every
side except a ‘wide margin AAA, &c., and in
putting them together, two floor—plates of iron,
131;, were interposed between the lower and
middle and the middle and upper box, so as
to make each a convenient working-place for
one miner. The whole shield therefore ad-
mitted 36, in three tiers or stories, and each
had commonly only one of the polings before
his box removed at a time, as shown in the
middle box, Fig. 2191, though in good ground
two were allowed to be taken at once, as
shown in the lower box. In case of an un-
controllable “ run” or irruption of quicksand
into any box, that box had its sides and en-
trance barricaded with boards, and the influx
efiectually confined to it, until the compression
of the matter intruded made it manageably
firm, so that it could be removed, and the
box again taken possession off ; and in this
way, scvera “runs” that would otherwise
have been quite ruinous, were mastered with
a few hours’ delay only. Olay would often in-
trude itself illimitably through apertures hardly
perceptible, or not admitting a finger.
Before proceeding to the modes of support-
ing and managing the polings, we must notice
the singular mechanism for moderating the
friction, which, in pushing any frame forward
simply by the two great screws ff; would
have arisen from its contact all round, both
against the roof and floor of the excavation,
and against its neighbours, all being strongly
bound together by the tendency of the earth
to collapse upon them in every direction. The
friction against the roof and floor (which might, it
seems to us, have been very simply obviated by a
mounting on broad-tired wheels,) was met by a very
complex and unique contrivance, compared to a man’s
arms, legs, knee-j oints, ankle-joints, feet and shoes;
and apparently planned only to exhibit this fanciful
resemblance, for the mode of progression with these
members was so entirely different from walking, that
TUNNEL;
871*
much seems to have been sacrificed to (rather than
gained by) this unreal imitation. Though each frame
had two legs, K K in the above figure, and x KK, 820.,
in Fig. 2191, the two were not lifted or advanced alter-
nately, but both at once, as in using crutches, so that
0726 central foot would have answered every purpose of
the two. During their relief from pressure by shorten-
ing them, for each was a great screw-jack, and tumed
by levers inserted into M, the frame was upheld by its
arms, (also called shag/8,) one of which appears at o c,
Fig. 2191, which either hung from, or bore upon the
neighbour frames on each side. These arms, 11 in
number, connecting each frame with the next, might
be lengthened or shortened to a certain extent by
wedges placed in them at 1?. When Zengz‘fiened, they
3
.r-
Fig. 2191. sncrzox or FRAME, I}:


acted as pillars to lift up those frames to which their
heads were connected, and throw all the weight on
the six other frames which their lower ends bore upon ;
but when shortened, they acted as slings or suspenders,
to draw up these latter frames, and hang their weight
to the intermediate ones, which before were lifted,
but now bore on their legs and feet. Thus, by these
two actions, it was easy alternately to relieve the
legs of all the six even-numbered, or all the six odd-
numbered frames from pressure, and consequently
from friction against the floor; and the travelling of
the whole shield resembled that of a rank of twelve
men not walking, but each of whom advances both
feet at once, by hanging with his arms on his two
neighbours as crutches, and then in his turn stands
A LINE PARALLEL WITH THE DIRECTION OF THE TUNNEL.
872
TUNNEL.
still to serve as a crutch for them in their advance.
Each move of every frame was exactly 6 inches, viz.
from 3 inches behind its neighbour frames to 3 inches
in advance of them ; and the whole shield never stood
in one ever. rank, but six alternate frames always
3 inches behind or ahead of the others; and this dis-
tance was, in the second shield, accurately maintained
by a kind of stops to their motions, inserted between
the upper and between the lower boxes at g r s, Fig.
219.0, and called the regulators.
There was nothing in the original shield (used up
to the second irruption, and exhaustion of the Com-
pany’s funds in 1828,) to obviate the friction of one
frame against another, except small rollers and wedges
introduced at discretioh. The consequence was, that
they often get into actual contact, and the enormous
sliding friction to be overcome when they were thus
jammed, led to continual fractures of themselves,
their legs, arms, and abutment screws. Fig. 2192
shows the means by which they were kept apart at
one constant distance of about 3 inches, in the im-
proved shield. It is the underside of the front ends
of three contiguous floor—plates, and there was a
similar appendage to their hinder ends. The two
sectors ll, (called quacimrzz‘m) turned on centres in
the even-numbered frames, and entered into two re-
cesses m m, Figs. 2190, 2191, attached to each odd-
0 o N o numbered one. Every
( jijlzzzé P frame was steadied in its
| t
Fig. 2192. before and two behind,
upon each of its two floor—plates. We speak of
course of the 10 frames from No. 2 to 11 inclusive,
for the two extreme ones necessarily difiered in many
respects from the rest, which were all alike.
The mode of working can now be understood from
the three figures
I, 11, III, Fig.
2193, exhibiting
three positions of
the fronts of three
contiguous frames
and the polings
before them. Each
g____ poling was sup-
a” 72:» " '- ported against the
earth by two small
screw-jacks, ap-
plied. to hollows in
its face, lined with
iron near its ends,
and abutting by
their tails against
the upright sides
of the frames.
This being the
condition seen at
I, and the 6 odd—
numbered frames
being 3 inches behind the others, the miner in the
middle box of the figure (being an odd-numbered





these sectors, two acting
If"
AA.__ _.
% sis


' __._.-_.qr_fi,_ __ “_ ._



Fig. 2193.
advance’ between 8 of'

one), loosened the two screws supporting the upper-'
most poling before that box, removed the poling, and
3 inches of the ground before it, and replaced it in
one plane with those on each side of him, as seen at
II, only resting its screws now not against his own
frame, but against its neighbours on each side, as
shown in the figure. He next loosened the second
of his polings, and when all had successively been
worked forward, as the same process was going on
in all the 18 cells of the 6 odd-numbered frames, the
whole of the polings were brought into one plane.
In Fig. 2191, we have shown this process completed
in the top box, 6 polings replaced, and the 7th open
in the middle box, and 3 replaced and 2 open at
once in the lower box. When all were worked for-
ward, it is plain that they would abut solely on the
6 even-numbered frames, leaving the others free to
be advanced from A to B, Fig, 219 3, which was done
by throwing their weight on their neighbours by the
arms or slings 0, Fig. 2191 ; then placing the shoes L,
which were thus left free, 6 inches further forward,
which brought the legs into the sloping position there
shown, then screwing on the whole frame that dis-
tance by its 2 abutment screws, ff, and, lastly, by
relieving the slings, resting it on its own feet again
in a position 3 inches before, instead of 3 inches
behind its neighbours, as outlined at B, Fig. 2193. The
same polings were now removed again in the same
order as before, and another 3 inches excavated, and
the poling screws replaced against their own frame, as
at III, Fig. 2193, which, it will be observed, is in
the same condition as 1, except that the odd tiers of
polings are in advance of the even ones. The same
processes were now repeated, therefore, to advance
the even-numbered frames, and the whole brought
into its precise original condition, when every part
is 6 inches further forward. Most of this immense
work was excavated by the bare hands, without
tools.
The protection of the top and sides, as well as of
the front, was in numerous, narrow, horizontal pieces,
which were called stares, and being pushed forward
as the work advanced, were of iron, and elaborately
contrived with a view to serve throughout the under-
taking. In Fig. 2191, both the top and side ones
are seen out transversely, and in Fig. 2190 a top stave
cut longitudinally at QQ. These were made to slide
with as little friction as possible on supports R, called
saddles, and were each separately adjustible by the
screw-jacks aw, so as to press them up with more
or less force, and preserve the different inclinations
necessary in the curved descent and ascent given to
the tunnel. Each stave, whether of the top or sides,
was in 4: lengths, as seen in Fig. 2191, 3 of cast-iron
and 1 of wrought, the foremost entering like a chisel
into the ground, 6 inches before the face of the
polings, and the hindermost, called the tail, being
a thin plate overlapping the brickwork some inches;
so that the staves covered the edges, both of the front
plane and of the new face of brickwork, as those of
a cask do the edges of both its heads. It is one of
the remarkable instances of the hurry and thought-
TUNNEL—~TURMERIO—TURNING.
572;
lessness which characterise many great English
engineering works, that even so simple and ob-
vious a piece of design as this, had to be evolved
by the most ruinous experience. The staves of
the original shield had actually neither cutting
points nor tails, that is, the meeting of the lateral
and top protections with the front one was left to
be made good by random expedients, and opened
entirely at every move of the polings; and the
whole, instead of enclosing and embracing the end of
the brickwork, like the cover of a telescope or band—
box, was simply placed before it, with sutficient in-
terval generally to allow for the building it forward.
It is equally inconceivable how, with all these pre-
cautions against the softness and pressure of the
ground in every other direction, that from below could
be so utterly ignored as to omit, at first, not only all
protection of the floor of the excavation similar to
that applied against every other part, but even all
means of spreading the pressure of the frames over
it, beyond the shoes that were of necessity placed
under the very questionable contrivance of legs,
or rather stilts. Still more remarkable is it that even
when the necessity of planking under the brickwork
presented itself, soon after the commencement, this
planking was not extended under the shield, but each
plank was laid down 5elzz'acl instead of before its feet,
WlllCll, of course, sunk into the clay, or adhered to it
immoveably, and the effects were augmented, and
continual fractures of the legs produced, by their
being, in the first shield, rigidly connected with the
feet, instead of with an universal joint or ankle. At
length the planks were laid before them, close up to
the lower polings, and recognised as part of the
general lining that left no earth bare, except the
points at any time being excavated. This floor is of
elm, 8 inches thick, like the temporary protections.
In the general form of the shield, and, conse-
quently, of the whole work performed with it, the
rectangular section of the whole prism excavated and
filled with brick, it is difficult to overlook the great
waste of human labour and life, caused by men and
companies, who undertake such works on the sup-
position that the wlwle of ' the thought about them
can be delegated to others. It can hardly be ques-
tioned that the flat top and vertical sides render this
shape nearly, or quite the worst for its permanent
functions as a tunnel through settling and yielding
clay; and the fact of every one of the five irruptions
occurring at an upper corner of the prism forcibly
suggests the question whether, had there been no
upper corners, there would have been any irruption.
Moreover, every irruption was into a space (the outer
spandrils) that it was not only totally needless to
excavate and useless to fill, but which had actually
better, for the permanent uses of the work, have
been occupied by the natural ground than by the
masonry now filling it. On looking at the well-
known cross section of the tunnel, it would seem
that no portion of the flea-radiated brickwork, except
that between the heads of the tunnels (which ought
to have had about half its material saved by a
r
cylindrical perforation) adds anything whatever to the
strength of the work; while it certainly made the
liability to dislocations of the ground, above the
rectangular corners, a maximum. Here is about one-
eighth of the whole bulk, then, excavated, only to be
filled up again with, at least, a third of the whole
masonry, or several million bricks, for no apparent
reason but that the shield might be rectangular, that
is, might admit of all its 12 portions being alike, or
made to one design, instead of the six designs that
would have been necessary had they diminished in
height from the centre to the sides to suit an oval, or
other better and more economical cross section.
TURBETH MINERAL, a term applied to the
basic sulphate of mercury, 3HgO,SO3, from a simi-
larity in its medical efiects to those of the root Coa-
volvalas Tarpetllam, which is violently cathartic and
emetic. See MERCURY.
TURF. See FUEL.
TURKEY-RED. See CALICO-PRINTING—DYEING.
TURMERIO, the root of the Careama loaf/a, a
native of the East Indies, and cultivated about Cal-
cutta, in Bengal and China. It is one of the consti-
tuents of curry powder and curry paste, and it is
also used as a condiment, and as a colouring matter.
The roots, or rather tubers of turmeric, are known in
commerce as roaacl and long. The round tubers are
about 2 inches long, and an inch in diameter, pointed
at one end, and wrinkled. Long turmeric is cylindri-
cal, about 21; an inch thick, 2 or 3 inches long, and
somewhat contorted. Both varieties are greyish-
yellow externally, and. internally of an orange-yellow
passing into brown. The fractured surface appears
waxy; the odour is aromatic and peculiar, the taste
aromatic, and the tuber when chewed tinges the
saliva yellow. The colouring matter of turmeric,
eareamz'ae, has been isolated; it is an inodorous,
transparent, reddish substance, not crystalline, and it
acquires a fine yellow colour when rubbed to powder.
1t fuses at 105°, and is scarcely soluble even in hot
water, but readily so in alcohol and ether, and in fat
and volatile oils, so that it resembles the resins in
character. Ourcumine forms red solutions with sul-
phuric, hydrochloric, and phosphoric acids, and on the
addition of water, a pale green floeculent precipitate
is produced. It forms reddish brown solutions with
the alkalies, and hence the use of turmeric paper as a
test. For this purpose, it is best prepared with a
strong tincture of turmeric in proof spirit.
TURNING is the art of shaping wood, metal, or
other hard substances into round or oval figures, by
means of a machine called the latte.
This art is of very ancient date. The potter’s
wheel, which is a lathe with a vertical instead of a hori-
zontal axis, is mentioned in the Old Testament. Several
of the ancient writers refer to the art. Pliny names
Theodore of Sames as being the inventor of the art,
and refers to one Thericles, who was famous for his
skill at the lathe. It was a common expression
among the ancients, that anything done accurately
and delicately must have been formed in the lathe.
It is scarcely possible to over-estimate the import
874i
TURNING.
ance of this art. The various engines and machines
employed in converting the numerous raw produc-
tions of the earth into useful fabrics and articles of
comfort, convenience, or necessity, could scarcely
exist in‘ the absence of the lathe, and of the tools
required for the accurate production of the circular
parts which enter so largely, and so importantly, into
their structure. Without the lathe, the production
of the steam-engine would scarcely be possible, so
much does the circle abound in its various parts.
The same remark applies to the steam-printing ma-
chine, and to a large number of the most important
instruments of science. Indeed, it is not too much
to assert, that nearly'all solid objects, especially of
wood and metal, in which the circle or any of its
modifications can be discovered, are the offspring of
the lathe.
In the operation of turning, the work to be re-
duced to shape is put into the lathe, and made to
revolve with a circular motion about a fixed line or
axis: the external surface is then worked to the
intended form ‘by means of edge-tools presented to it
and held fast down upon a ‘fixed rest. The projecting
parts of the work, by its rotatory motion, are brought
up against the cutting-edge, and are cut off, and thus
the outer surface is so reduced as to be at an equal
distance from the axis of motion, and, consequently, .
it has a circular figure. In general, the axis, or centre *
line of the work, coincides with the centre of any sec-
tions made by planes perpendicular to such axis. A
piece of work may, however, have '2 or more centre
lines in different parts, or in different directions ; but
in such case the work must be turned at 2 or more
successive operations. Or the position of the axis may
be rendered movable during the revolution of the
work, as in oval and rose-engine turning. The work
may also be turned hollow, with a cavity inside; or
the exterior surface may be fluted, or grooved, or
variously shaped, or the work may be turned both
inside and out.
The essential properties of the lathe for outside
work are two points, which will firmly sustain the
work at each end, and still allow it to turn freely
round upon its axis; secondly, a rest‘ or support for
the tool; and thirdly, some contrivance for turning the
work round. For hollow, or inside work, the work
cannot, of course, be supported at both ends: it is
therefore fixed securely to the extremity of a spindle
or mandrel, which, on being turned round, carries the
work with it, and the tool, being applied to the free.
end of the work, produces a hollow or excavation.
There are many forms of lathe. Where the work
is supported at both ends it is called the centre ltd/26,
and when fixed at the projecting end of a spindle, it is
called a spindle, mrmch‘el, or aims/a lat/w. Lathes are
also named from the different methods of putting
them in motion,’ such as the pole latte, the land-wheel
1611/16, the foot-wheel lathe. For very powerful works,
lathes are turned by horse—power, water, or steam.
The lathe is then called a power lat/w.
The lathes used by the turners in wood are gene-
rally made of wood, and of simple construction; they

are called dell—16117268.‘ the .lathes used for turning iron
and steel are of similar construction, but different
material; but the best work in metal is done in an
iron lathe, which, when made with a triangular bar, is
termed a bar-latte. The small lathes used by watch-
makers, called tum-benches and teams, are similar to
centre-lathes, only smaller, and made of metal.
The centre-lathe, Fig. 2193, which is the most
simple, consists of 2 beams of wood fixed horizontally
on legs like a bench, forming the bed of the lathe.
The beams are fixed a small distance asunder, ‘the space
between them being for the reception of the tenons
at the lower end of the puppels, or short posts, which
rise perpendicularly from the bed, and are firmly fixed
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2194. POLE-LATHE.
thereto by means of cross wedges passed through the
tenons beneath the bed. One of the puppets carries
an iron pin, and the other tenon has, at the same level,
a centre screw working through a nut. Both the
screw and the pin are furnished with sharp steel
points, which pass into the ends of the work, and hold
it securely. The rest, for the support of the tool, is
a rail, or bar, extending from one puppet to the other,
and lying in hooks projecting from the puppets. The
work is put in motion by means of atreadle worked
by the foot. A string or cat-gut is fastened to the
treadle, and, passing 2 or 3 times round the work, is
attached to the end of an elastic pole or 161111, (whence
the origin of the term lat/re or pole {611%,} fixed to the
ceiling over the head of the turner.
In using this lathe the workman moves the treadle
with one foot, and placing a gouge or chisel on the
rest, he brings the edge carefully up to the work;
the pressure of the treadle causes the work to turn
round against the edge, which cuts it ‘to a circular
form. When the treadle touches the ground the man
takes off his foot, and the elasticity of the pole draws
up the treadle and turns the work back again: during
this backward motion the tool cannot cut, and is re—
moved from the work, but is again applied when he
begins to press down the treadle. The desired effect
on the wood must be produced gradually so as not
to leave ridges; and knots in the wood must be acted
on gently, or the wood may be split or the edge of
the tool turned. For light work, a bow is hung over
the centre of the lathe, as in Fig. 2194', and the
string from the treadle is tied to the middle of the
bow-string, which acts instead of the pole. The centre-
TURNING.
825
lathe is an imperfect machine when worked as above
described, but its great simplicity causes it still to be
used for turning the legs of stools, chairs, tables,
staircase-rails, &c., in soft wood. It is also used in
Spitalfields by the bobbin-turners, who work in alder,
&c. In centre-lathes, the work is sometimes put
in motion by a large heavy wheel turned by one
or two labourers. An endless-cord passes round a
groove in the circumference of the wheel, and after
crossing, like a figure of 8, goes over a small
pulley attached to the work. By this means the
work receives a rapid motion, and has the advan-
tage of turning in the same direction, so that the
action of the tool is continuous. The centre-lathe
will turn any kind of work that can be supported
both ends. For turning heavy work, such as mill-
wrights’ and iron-founders’, the puppets are secured
to the bed by means of nuts and screws instead of
wedges, and to put the work in motion, the centre-
pin of one puppet projects considerably, and a pulley
is attached to it, so as to turn freely round by means
of an endless-band or strap, which communicates
motion from a great wheel, moved by water or steam-
power. From the pulley, a pin projects in a direction
parallel to the centre-pin, and a piece of iron, called
a driver, is secured to the end of the piece of work so
as to project from it sufficiently to be intercepted by
the pin which is fastened to the pulley, by which
means the motion of the pulley is communicated to
the work. ‘
The spindle or mamZrel-Zwt/za-Fig. 2195, is arranged
for turning hollow work, and also centre work, as in
the centre-lathe. Motion\ is given to the work by
means of the foot, so that the turner has both hands
at liberty. AA are uprights~of oak or mahogany,
which support the bed 13, consisting of two bars of
iron, with a space between them. Lathes entirely of
metal are subject to an elastic ‘tremor, which is un-
pleasant and injurious. c D is a cast-iron frame
fastened to :B for supporting the spindle or man-
drel a d: n is the back puppet, used .to support one
end of the work G, the other end being fixed to
the extremity of the mandrel, and turned round by
it. n has a cylindrical pin fitting it, and the end
of the pin has a conical point or baa/r centre, which
penetrates and supports the work, and the back
centre can be moved forward by means of the screw
6, while a clamp screw E binds the pm when adjusted.
The back puppet is secured to the bed 13 by a tenon,
which enters the groove through the bed, and a
screw descends from the tenon quite through the bed
and projects beneath it: upon this screw a nut g is
tapped, and by turning it, the shoulder of the puppet
E is drawn down firmly to the bed; and when the
nut is loosened the puppet can he slid along the bed,
and adjusted at any required distance from the ex-
tremity of the spindle, according to the length of the
work e. The point of the back centre must be
exactly in the centre line of the axis of the motion
of the spindle a b; for which purpose the upper sur-
face of the bed must be straight and flat, and the
groove straight and parallel; the frame of the mandrel

must be so fixed to the bed that the centre line of
the mandrel is exactly parallel to the bed and to
the groove. The neck of the mandrel requires to be
accurately fitted into the collar, so as to. turn smoothly
without shaking. The neck at one end projects
beyond the collar, and the projecting part is formed
' 71.
' 6



L
Fig. 2195. smxnnn on mxnnnnn LAID-HE-
to a screw for fixing the work to it. Upon this
screw various pieces called c/mc/ts are fixed, each
chuck being adapted to hold a different piece of
work. The chucks screw up against a shoulder on
the end of the mandrel, and by the motion of turning
round in the direction in which the lathe works, the
chuck is screwed fast against the shoulder; or the
neck of the mandrel may be perforated and cut with
an internal screw, an external screw being attached
to each chuck. The other end of the mandrel is
supported by a point or in a collar. When made with
a pointed end, the point is received by the end of a
screw tapped through the part 1) of the frame of the
mandrel in the place of the end a. By turning this
screw the mandrel can be adjusted. The mandrel is
turned round by a cat-gut band, oassing round the
pulley it, and the large iron foot-wheel H attached to
the end of the axis I. This axis has a crank in the
middle, which is united by an iron link K to the
treadle L. The treadle 'is fixed by 3 rails to an axis
M, on which the treadle moves. The wheel 11 is
heavy in the rim, and, being firmly fixed to the axis I,
turns round with it: the momentum acquired by the
wheel is suificient to turn the work while the crank
and treadle are rising. When the crank has passed
the vertical position, and begins to descend, the
workman presses down the treadle, which gives to
the wheel sufficient impetus to bring it round to the
same point. The link K must be of such a length
that when the crank is in its lowest position the
board L of the treadle shall be 2 or 3 inches from the
floor. The lathe is set in motion by moving the
wheel by hand until the crank has just passed over
876‘
TURNING.
its highest point; the motion can then be continued
by the foot. The man must stand steady before his
work, and not move his body while his foot rises and
falls with the treadle. The band which communicates
motion from the great wheel to the small one should
be of strong cat-gut, united by means of a hook and
eye of iron, and furnished with a screw. The cat-gut
is to be slightly tapered off at each end by a sharp
knife so that it will just enter the hook and eye : the
band is then held firmly in a vice in the left hand,
and the hook and eye are taken up in a pair of pincers
held in the right hand, and are screwed upon the cat-
gut until quite firm. This is a better method of joining
than others which are usual. The rest N is fixed to
the bed by its foot, which is forked so as to receive
a screw-bolt which passes down through the lathe-
bed and secures the rest at any point of the bed by
a nut k. The groove in the foot allows the rest to
be moved to and from the centre of the work, so as
to adjust it to the required diameter of the work. The
rest may also be adjusted as to height by making the
piece on which the tool is laid with a shank, shaped
like the letter T, the shank being a round pin passing
into a socket in the foot of the rest, and held at any
required height by a clamp-screw N. In turning
cones or similar work the edge of the rest M, Fig.
2197, is placed inclined to the axis of the work.
Rests are made of different sizes to suit different
kinds of work. There is also a circular rest, which
enables the turner to ornament balls, spheres, and
round objects.‘
The tools used by the turner are gouges and chisels
of various sizes and forms. The gouges are first used
to rough out and form the wood, and the chisels to
smooth it and reduce it to the required form. The


Fig. 2197.
Fig. 2196.
blade of the gouge is formed nearly half round to an
edge, and the two extreme ends of this edge are sloped
off a little, so that there may be no corners to catch
in rough wood. The blade of the gouge is held con-
siderably inclined, as in Fig.2196, so that the bevel or
outside of the edge may form nearly a tangent to the
circumference of the work, and the cutting edge be
above the level of the centre. The chisels are usually
ground with a bevel on either‘ side. In some cases
the line of the edge is inclined to the direction of the
blade 3 or it may be rounded to a semicircle, or made
with angular points like spears. In using chisels,
the rest is raised considerably above the centre of
the work, and the line of the cutting edge is made
oblique to the axis of the cylinder, to prevent either
angle of the chisel from running into the work. The
chisel must ‘be gradually traversed along the work.
For turning hard woods, ivory, and bone, the points
or cutting edges of the tools are bevelled on one side

only, and the angle of the edges is obtuse. The tools
require frequent sharpening with a grindstone and
bone.1 The turner
also uses callipcrs
for inside and out-
side work, Figs.
2198, 2199, and
guages to regulate E
the dimensions of
his work, and he
has a great variety
of chucks. Those
of wood are usually a V
hollowed out, and the work is jambed into the cavity.
The turner also uses certain small tools called milling
tools: they are small wheels, on which a pattern is
out, and being pushed close up to the wood, a few
turns of the lathe impresses the pattern clearly
upon it.
The wood to be turned is rounded with a small
hatchet, or with a plane or rasp before it is put into
the lathe. The true centres of its two end surfaces
must also be found, so that they may be exactly
opposite each other when the centre points of the
puppets are applied to them. To find the centres lay
the piece of wood to be turned upon a plank; open a
pair of compasses to nearly half the thickness of the
piece; place one of thelegs of the compasses on the
plank, and let the point of the other describe an are
on one of the ends of the piece when laid flat on
the plane'of the plank like a roller. Turn the piece
one fourth round and describe a second arc ; turn it
another fourth and describe a third are ; turn it again
and describe a fourth; the point within the intersec-
tions of these arcs will be the centre of the end.
The centre of the other end maybe found in a similar
manner.
When the work is- turned and the ends made flat
it is polished. The polishing material for soft woods,
such as pear—tree, hazel, maple, 850. is shark skin or
Dutch rushes. Ivory and horn are polished with
pumice-stone or chalk: the metals with tripoli and
putty-powder, and so on. .
A convenient form of chuck is shown in Figs.
2201, 2202. It can be screwed to the mandrel at a.
There is a hole in the centre of it at Z), for the recep-
tion of the piece of wood or ivory which is to be
turned. The chuck is divided at the end I) by two


Fig. 2198. Fly. 2199.

(1) The most complete and admirable account of the tools used
in the various descriptions of turning will be found in the three
published volumes of Holtzapfi‘el’s “ Mechanical Manipulation.”
The premature death of the author leaves a blank which will not
be easily supplied, since it unfortunately happens that those
gifted men who have passed a life-time in the engineer's work-
shop, are not willing to submit to the labour of reducing their
knowledge to writing, even if they have the power. Mr. Holt-
zapfi'el was a good writer as well as a first-rate meclranician. His
work was to have extended to 6 volumes, the fourth being on
“ The Principles and Practice of Hand or Simple Turning; ” the
fifth, on “ The Principles and Practice of Ornamental or Complex
Turning; ” and the sixth, on “ The Principles and Practice of
Amateur Mechanical Engineering.” We are glad to hear that
the author has left copious notes for the three remaining volumes.
Let us hope that they may be worked up by the friendly and
competent hand of some brother engineer. -
TURNING. \
an
saw-kerfs at right angles to each other as shown in
Fig. 2201, by which means the end expands a little
and holds the work fast, and further to aid this, the
outside is made to taper slightly, and is furnished
with a hoop or ferril which on being driven up closes
the 4! segments and binds the work. Fig. 2200, is a
brass box Z2, which screws to the mandrel at a, and
holds a wooden chuck which is thus prevented from
splitting. It is usual, however, to smear the work
with a bit of chalk to prevent it from slipping in
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Fig. 2200. Fig. 2201. Fig. 2202.
common cap chucks ; or a thin piece of paper may be
inserted between the work and the chuck. Figs.
2203, 2204, are forms of chucks for centre work,
the points 060, Fig. 2208, or the point 6 and the
chisel edges 00, being useful for holding the work.
Fig. 2202 is used for hold-
ing the balustrade which is
being turned in Fig. 2195.
g When apiece of metal-work
is turned between centres,
a small chuck with a square


Fiy. 2203?
Fig. 2204.
hole is used at one end, and the work has a square
filed on it to fit the chuck: the other end of the
work is supported by the back centre. When great
accuracy is required, as in turning arbors, screws, axes,
spindles, &c. a chuck, Fig. 2205, is screwed to the
mandrel at a, while at [2 is a steel centre point ex-
actly in the centre line of the mandrel; the work is


Fig. 2206.
'Fig. 2205.
mounted between this point and the point at the
back centre, and the motion of the mandrel is im-
parted to the work by means of a driver, Fig. 2206,
screwed to the end of the work and consisting of an
iron ring with a screw (Z, tapped through one side of
it and made tight upon the work, so as to prevent its
slipping round; on the opposite side of the ring is a.
projecting tail f; Fig. 2205, which fits into a claw l: e
passing through the chuck and fastened by a screw:
the stem l: is also adjusted in the socket of the chuck
by means of a screw. It will be seen by the form of
the driver, Fig. 2206, that the angular shape of the
side opposite to the screw allows different sizes to be
used in the same ring. To prevent the screw from
bruising the finished end of the work, a piece of iron
may be interposed between the screw and the work.
Iron or steel must be very accurately adjusted in the

lathe previous. to turning, and when the points of
adjustment are found, holes are drilled at the two
extremities of the work for the reception of the points
of the lathe. The tools used for turning metal are
very different from those used in turning wood.
Different substances require different velocities of
motion in the lathe to be acted on properly. Wood
can scarcely be made to move too quickly, but the
shavings should be thin. Brass and bell-metal may
be moved quickly, but not with half the velocity of
wood. Wrought-non and copper must be turned
more slowly, and the tool kept cool by means of water
trickling on it. Steel should be moved with some-
what less velocity than wrought-iron: it is liable to
have hard veins in it, which the workmen call pins:
these will be cut through if the work move slowly,
but if a quick motion be attempted, they will destroy
the edge of the tool. Cast-iron must be moved the
slowest of all. The difierent degrees of velocity are
obtained by the foot-wheel of the lathe, Fig. 2195,
having grooves of different diameters, and the man-
drel pulley it has also different sizes. By shifting the
band to different grooves the velocity may be re-
gulated.
In cutting screws at the lathe a pattern screw a,
Fig. 2195, is fitted to the end of the mandrel, for
which purpose the mandrel is fitted in a collar at eaqli
end, and the necks are cylindrical so as to admit mandrel moving endways at the same time that it
turns round. On the extreme end of the mandrel
beyond the collar D, the pattern screw is fixed; the
distance of its threads corresponds with the screw in-
tended to be out upon the work, and which is fixed
in the lathe by a chuck: at n is a piece of brass cut :
with threads adapted to the pattern screw, and which
can by turning a screw be drawn up against the
pattern screw so as to work in its threads.
In this condition the mandrel in turning
round will also move endways in its collars
with a screwing motion, so that if a cutting
tool be firmly held to the work in one posi-
tion, it will cut a spiral channel or screw
upon its circumference. This is a more
accurate method than cutting screws ‘fig/ing,
as it is called, with the tool, Fig. 2207, Fig. 227.
applied to the work and moved along endways while
the work turns round so as to cut a spiral. Outside
and inside screw tools are used in fitting the screw
top to a turned box, &c.
In order to form ornamental patterns on the work,
various chucks are employed, all of which screw on to
the nose of the mandrel, so that one lathe suffices for
various kinds of work. With the concentric or
common chuck, as aheady noticed, all the articles
turned are circular, and the lines which form the
circles are enlarged or diminished according as the
tool approaches or recedes from the axis. By means
of the ea’eenti-ie chuck the patterns are still‘ of a
circular form, but the centre of the work can be
shifted at pleasure. The coal or elliptic chuck designs
oval or elliptical figures. The geometric and com-
poanrl eaeentrie chuck produces beautiful geometric


878
TURNING.
and curved designs. The az’Jlz'gzre and the epz'aycloz'dal
chucks also turn curious and intricate patterns, and
the straight‘ line chuck performs all its work in straight
lines. Many of these chucks are complicated and
consequently very expensive. One of them, of
peculiar form and very intricate, is employed for
designing patterns on country bank notes and cheques,
in order to prevent them from being fraudulently
imitated.
The ingenious author of the “ Handbook of Turn-
ing,” (1842,) remarks that there are two points of
perfection in the art; one, where the extreme delicacy
or elegance of the object renders it admirable, and
the other, where it is difficult of execution; and in
general turned works are admired by amateurs in pro-
portion as they are opposed to the circular figure.
“Those who are very learned in this art can, out of a
piece of ivory or mother-of-pearl, produce in the lathe
beautiful brooches, ear-rings, and studs, worked in
raised flowers, chess-men in imitation of carving,
and ornamental vases full of detached~fiowersg while
fluted and spiral columns, delicate mouldings and
fanciful headings, are of comparatively easy execu-
tion.”
The excentric chuck is a very useful appendage to
the lathe. By its means the turner can change the
centre of his work at pleasure, and produce a great
variety of circular lines of varying size, together with
other ornaments. In turning patterns, however, the
tool should be held in a sliding or parallel rest, other—
wise exactness and delicacy of work cannot be
ensured. Moreover, with the excentric chuck, the
slide rest marks the size of the circles, while the
chuck fixes their positions. The excentric chuck is
represented in two positions in Figs. 2207 ,- 2208. a
is a socket for screwing to the mandrel; 6 6 the
chuck, formed in the same piece with the socket a ,-
in front of the chuck is a dove-tailed groove, formed
by two pieces dd screwed to the chuck: in this
groove is fitted a slider ea, to which a centre pin is
fixed, and a circle f fitted to the centre pin so as to
turn round freely. A screw 9 projects in front of the
circle for fixing chucks thereto. A screw It allows
the slider to be




1’ retains it firmly in
the


I: gradually moved
in the groove, but
5
an


position in
a‘
l




L .5“
which it is paced,
‘5 -. -* By means of this
i ““““ " E125”! screw the centre
pin of the circle f


w‘


can be made either
. to coincide with
the line of the
Fiy- 22°9- mandrel, or it can
be set with any required degree of excentricity from
the mandrel, as is shown in Fig. 2209, by the diffe-
rence between the line of the screw g and that of the
socket a. The circle is divided round the edge with
equidistant notches or teeth ; and a tooth or catch 72
is fitted on the slider by a centre screw, and has a


ti llhl‘
llflllllillmllg
Fig. 2208.

tooth which can be inserted into any of the teeth at
pleasure, so as to prevent the circle from turning
round upon its own centre pin. The work which is
fixed to the screw 9 will evidently turn round with the
mandrel. Now when this chuck is screwed to the
mandrel by the internal screw at a, the screw in is
turned until y is brought exactly into the line of
the mandrel. A wood chuck is next screwed on
at g, and the work fitted to it and turned to its re-
quired figure as in ordinary turning. The face of
the work is then ornamented by tracing a number
of circles upon it. The screw 1: is first turned
until the centre of the circle f is removed to a given
distance from the line of the mandrel; the tool in
the slide-rest is then brought up to the work, and a
fine circular line out. Such a circle is evidently not
in the centre of the work, but removed therefrom to
a distance equal to the degree of excentricity given
to the slider. One circle having been described the
lathe is stopped, the catch it released, the circle f
moved through the space of one tooth or notch. The
lathe is again put in motion, and another circle de_
scribed by the point of the tool held in the same posi—
tion as before; but the circle thus described will fall
on a different part of the work to the circle first
described, but its centre will be at the same distance
from the centre of the work. On stopping the lathe
and turning the circle f round another tooth, a third
circle is described, and when as many circles have
been described as there are teeth in the circle /; the
ring of circles is complete. It will contain as many
circles as there are divisions in the circle f .- they will
all be of equal size, and their centres arranged at
equal distances round the centre of a small circle
which is concentric with the work.
A small instrument called an eccentric cutter is
often used by the ivory turner. It may be formed
like a drill-stock, and is moved by a how; but the
cutting point can be fixed at different distances from
the centre by means of a groove and screw. When
used with the click-plate on the mandrel, it can be
employed for ornamenting the sides, edges, or curved
surfaces of work. The excentric cutter and the
method of using it with the overhead/‘Mme, are thus
described in the “Hand-Book of Turning.” “ The
excentric cutter, Fig. 2211, fits into the sliding-rest,
but now it is no longer the work which moves round
while the tool is stationary, but the wood remains
fixed while the tool rapidly revolves and cuts the
patterns. For this purpose it is obviously necessary
that the fly-wheel should turn the cutter while the
small wheel remains immovable. Several methods are
used to perform this, but the one given in Fig. 2210
is the easiest. The frame here represented should
be of iron, firmly screwed to the bench of the lathe,
and of sufficient height to be about a foot above the
head of the workman. In front is a spindle which
works in 2 nuts 1, 1, exactly in a line with the
mandrel. Two wooden wheels 2, 2, are fastened to
this spindle, the one on the left hand remains sta
tionary over the fly-wheel of the lathe, by which it is
turned, the other slips backwards and forwards,
* TURNING.
*8‘79
according to the work it is required to do. Take off
the usual cat-gut from the fly-wheel, and pass a long
one over it and over the small wheel on the over-



my. 2210.
head frame No. 2. When the cutter, Fig. 2210, is fixed
in the slide rest, draw the other small wheel No. 2
on the spindle K, forward, till just above the rest,
then pass a cat-gut over it and round the small brass
wheel 13 of the cutter, and the whole will turn together.
The brass wheel of the lathe must then be fixed at
one particular number. It is usuallyr divided into
360 parts, each marked by a small hole, and it is by
properly dividing the numbers on this plate that the
accuracy of the patterns depends. To keep the wheel
OVLRHEAD MOTION .
steady, a small steel key In, Fig. 2210, is slipped into .
the brass knob 0, and the other end being pointed
enters into one of the small holes, and the work is
immovable until the key be moved into another hole.
The cutter, Fig. 2211, is of brass, with a spindle c,
which works in 2 brass collars K. At one end is the
wheel B, by which it is turned; at the other a steel
frame :01), which is marked on the upper edge in




Fig. 2211.
EXCENTRIC CUTTER.
small lines E to regulate the quantity of excentricity.
The steel tool-box 1* holds the tool, which is kept firm
by a small screw beneath. By means of a screw
through the frame D D, the tool is pushed backwards
and forwards, and cuts a large or a small circle. G is
the nut that moves it, and it also is divided into
numbers. The cutter for many patterns is quite as
useful as the excentric chuck, but in conjunction with
the former it is invaluable, and the patterns performed
by them may be multiplied according to the taste and
genius of the turner. The 2 screws H H fix the

depth of the cut; the wheel of the slide-rest deter-
mines the necessary distance, that of the cutter the
excentricity, while the brass wheel keeps the pattern
accurate. The tools used are of various forms and
sizes.”
Oval, or as it is more properly called elliptic fuming,
(for an oval is smaller at one end than the other,) is
performed by means of a chuck of peculiar construction.
The oval chuck (the invention of Abraham Sharp,)
consists of three parts, the c/mels, the slider, and
the eccentric circle. The chuck is secured to the
mandrel by a screw socket cut in a piece j; Fig. 2215,
which projects from the centre of it behind, so that
the chuck partakes of the circular motion of the
mandrel. In front of the chuck is a dove—tailed
groove formed by the pieces is’, Fig. 23141, for the
reception of a slider g )2, from the centre of which
projects a screw ll for the reception of a wooden
chuck which holds the work. By this arrangement
the work in turning round by the motion of the chuck
has a sliding motion across the centre, by which means
an ellipse is generated. This sliding motion is given
by means of the excentric circle, Fig. 2212, or ring of
brass fastened to the puppet of the lathe close to the
collar in which the neck of the mandrel runs. The
mandrel passes through the aperture l: the flat plate
m, which strengthens the ring, has at each end a bend
on with a screw in each exactly opposite each other:
the screws have sharp points for insertion in small
holes in each side of the puppet as at c, Fig. 2213,
the back of the plate m of the circle lying flat against
the front of the puppet 0; by which means the circle
is fixed. The 2 screws are horizontal, and both point
to the centre of the mandrel b; so that by screwing
one screw in and the other out, the whole circle may
be moved sideways horizontally, so as to give the
required degree of excentricity from the centre line
of the mandrel, and it will be held stationary wherever
it is placed. The back of the chuck, Fig. 2215, shows
2 grooves made through it in the direction of the
length of the slider, for admitting the shanks of 2
pieces of steel an to pass through the chuck; they
are attached to the slider g by screws in front, as
shown in Fig. 22141. The two inside edges of a 72 are



W '-
- EF-J-Efflll ' " m
YE-‘nlsi' ‘mlmmlidifwu Bigllllllflll
‘- ' innit?
I
“ ;__-,F~"'7‘{f’
“it
n. 0


























it ~ tn .
‘i - i l liall l ‘.d. ' ' ll -. ‘elatézill'nt t. .llll casts! . ; ” i‘ W


l al-
Fig. 2214.
parallel to each other, and the distance between them
is equal to the diameter of the outside of the ring,
Fig. 2212, the ring being included between them
when the chuck is screwed to the mandrel b, and the
Fig. 2215.
880
TURNING.
circle fixed to the puppet c as in Fig. 2213. Now if
the circle be set concentric with the mandrel, the
chuck, the slider 51, and the work attached by the
screw it will all be concentric, and circular work will
be tlll‘llGCl, the slider being guided by its claws 72%,
which embrace the circle. In order to set the work
for an ellipse the point of a tool in the slide-rest is
placed opposite the work, so far from its centre that
it will describe a circle of a diameter equal to the
breadth or' smallest diameter of the intended ellipse.
The mandrel is now turned until the ‘ slider g is
horizontal; the circle is then set excentric from the
mandrel by means of its screws mm, by which means
the slider y will be moved in the groove of the chuck,
but the work will be moved with it to a greater dis-
tance from the centre, because the 2 steel pieces n 12
include the whole circle between them. “ The
quantity of excentricity given to the ring must be
equal to the difference between the two diameters of
the required ellipsis, so that the work shall move or
throw out a sufiicient distance to bring the point of
the tool as much beyond the circle first described, as
the length of the ellipse exceeds the breadth. The
point of the tool will now be at one end of the longest
diameter, and here we will commence to trace the
curve all round. In turning the mandrel round till the
slider becomes vertical it must return in its groove
to‘ the place it firstv occupied, viz. the centre; because
the excentric circle which guides the slider is not
excen-tric in a vertical direction, though it is in a
horizontal. In thismotion the point of the tool has
cut or described one‘ quadrant of an ellipse, because it
graduallyrl’approached the centre a quantity equal to
the excenti'iicity of-tbe ‘circle. By continuing to turn
the mandrel round further, the circle will cause the
slider to move out the other way from the centre in
its groove until it comes again horizontal, when it
will be at the greatest throw out, as the turners term
excentricity, and the point of the tool will be at the
other end of the ‘longest diameter, having described
one half the curve :' continuing to move forward till
the slider becomes‘~ vertical, it will become concentric
again, and‘- the tool'will be at the breadth of the
ellipse, having finished three quarters of the ellipse;
and'in turning the next or fourth quarter, the slider
throws out till it comes horizontal, and brings the
work- to the position where we first set out, viz. at its
greatest excentricity; and with the tool: at the end of
the longest ‘diameter of the ellipse.” 1 This chuck

(l) “ Rees’s Cyclopaedim” There are several excellent articles
on Turning in this work, to which we have been considerably
indebted in the preparation of this article.
are not accessible to the general reader we would recommend a.
work "among the Mauuels-Roret, entitled “N ouveau Manuel
complet du Tourneur.” Par E. de Valicourt, 3 vols. Paris, 1848»-
1853. This work is ‘chiefly cpmpiled from the celebrated treatises
of Plumier, Bergeron, Desormeux, Dessables, Mapod, and others,
which have long been out of print. With the exception of the
“ Hand-book of Turning,” there are very few works in English on
this important art. In 1817, “ Specimens of Excentric Circular
Turning,” was published by John Holt Ibbetson, Esq. ; and in
1825, a second edition of ‘the same work; and in 1838, a third
edition, greatly enlarged. In 1833, Mr.Holtzapfi'el published an
account of Ibbetson’s Geometric chuck, with specimens. In 1819,
Mr. C. H. Rich, of Southampton, published “ Specimens of the
But as these articles ‘

is sometimes provided with a click, or even with a
micrometer plate, for placing the ovals in different
directions. The oval and the excentric may also be
combined in one chuck.
Rose-engine teeming requires a particular adjust-
ment of the lathe in
addition to special
chucks for the produc-
tion of those patterns
of curved lines called
by the French rosettes,
from the slight resem-
blance which they bear
to a full-blown rose,
and hence the term
rose-engine. The rose- i ’
engine lathe differs Fiy- 2216-
from the common lathe in this, that the centre of the
circle in which the work revolves is not a fixed point,
but is made to oscillate with a slight motion while
the work is revolving upon it, the tool being all the
time stationary, and hence the figure will be “ out of
round,” as the turners call it, or will deviate from the
circular figure as much, and as often, as the motion is
given to the centre. See Fig. 2216.
All work which is to be figure-turned must be held
in a chuck screwed on to the end of the mandrel
T, Figs. 2217 , 2218, which being movable, gives
those deviations from the circular form required
to form the figured work. For this purpose, the two
standards e H, which support the‘ mandrel, are not
firmly fixed to the bed A, as in other lathes, but they
descend between the checks or cast~iron bed almost
as low as the bottom of the mahogany bed A, where
they are united by an axis P, which is parallel to the
mandrel, and supported on pivots at its ends, which
pivots being received in pieces of cast-iron descending
from the cheeks, and strengthened by an iron bar Q
extended between them. The two standards G H are
formed of one piece, and have a strong bracing of iron
between them. .
The work is fixed in‘ a chuck at the extremity of
the mandrel, and the tool is held by a slide-rest and
adjusts it to the radius of the rose or figure intended
to be cut. The oscillating motion is given to the
mandrel by means of metal rosettes or wheels fixed
upon the mandrel, each having its edge or periphery
indented and curved with a waving line, as shown in
Fig. 211-8.. The’ rosettes are acted on by a small
roller at the‘end of the piece rz, which is supported




THE RO SE .
‘by a triangular bar m fixed parallel to the mandrel
upon'the upper‘ end of curved arms. When the man-
drel revolves, the- e'minences and depressions of the
rosetteapplying themselves to the roller, which moves
on a stationary axis, willifie'ause a vibratory or oscil-
lating motion of the mandrel-and of the frame err,
Fig. 2217, which contains it. Within thecavity of the
bed A is a 'strongrspringapplied to the frame of the

Art of OrnamentafTQdi'hingf and also “ Tables by which are
exhibited at one view all the divisions of each circle of the
' dividing plate." The Mechanic’s Magazine also contains a num-
ber of valuable articles on turning.
. TURNING.
'881
mandrel, to restore the latter to a central or vertical po-
sition when disturbed therefrom by an indentation in
the rose. The mandrel 1n contains 17 rosettes of diffe-
rent patterns. Several are scolloped out like Fig. 2218,
but the number of waves or scollops difi'ers from 12,
as in the figure, to 1%. The socket for the piece at
can be fixed by its clamp-screw upon any part of the
triangular bar 222 in order to bring it opposite any one
of the rosettes which it is required to use. Other


manna _


"ll




i
_)


a
w.‘-
,., he».
lll all It





ll



l lllllll



lllll'lllllllllllllillllll


Fig. 2218. ROSE-ENGINE-
rosettes are furnished with convex protuberances.
In either case, if the pattern be fine, the wheel on‘ n
, which is
rounded, hardened, and polished, to diminish as much
as possible the friction of the revolving rosette. The
engine is not moved with the foot, but by means of
a hand-winch, 0, Fig. ' ,
spindle, which at the other end carries a small wheel N,
communicating by a band with the great wheel. The
spindle is supported in a frame attached to the lathe-
frame by a centre or joint on which it can be raised
up and fixed by a toothed sector to tighten the band
when required.
By means of a straight-line chuck,the patterns of the
rose-engine are made to follow a straight instead of a
circular direction.
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A slide-rest is now attached to all lathes except 1
von. 11.
those of the most ordinary kind. There are various
forms of this most useful instrument, one of which is
represented in the Inrnonucronr Essar, Fig. lxvi,
where it is applied to the turning of iron. Another
form is also shown in the steel engraving which ac-
companies the article Scnuw. It is also shown in its
proper position in the lathe in Fig. 2217, but in the
foregoing examples it is introduced as a subsidiary
piece of apparatus. We will now describe it more
specially. The foot of the rest is formed with a dove—
tailed groove, into which the head of a screw bolt
fits, and passing down through the bed is fixed in any
part by means of a thumb—nut /:, Fig. 2217. The
groove in the foot allows the rest to be moved to and
from the centre of the lathe to adjust it to the dia-
meter of the work. At the end of the foot is a cylin-i
drical pin fitting into a socket s, Fig. 2219, formed
solid with the lower slider K of the rest: the socket
is held fast upon the pin by means of a clamp~screw :
at the bottom of the socket is a notched wheel s, and
a catch t, fixed to the feet It to engage the teeth or
notches, by which means the sliders K can be held
fast at any required angle with the mandrel. The
upper part of the slide-rest consists of two horizontal
sliders, K and g, placed perpendicularly to each other :
z
at
lllltllt
yyyymlmmllmlllllttritium!!! ltlllllllllllt
' “aria,




'lfillimltkij




;.
u'umiw
m" ll‘lllllll



.- >.
w—

i ' rlk'lmillilfi 8
| :-
,__.____.

Fig. 221‘9. smnn-iins'r.
the tool is attached to one of these, and by means of
screws with handles the sliders and the tool can be
moved in any direction. K is a metal frame formed
from the same piece as the socket s: its upper surface
is flat, and on this a slider, or flat plate ee, is fitted
so as to move with ease and precision. In the open-
ing of the frame K is mounted a screw, tapped with
a piece of metal projecting from the lower side of the
slider, so that when the screw is turned round by the
handle at fitted t6 its square end, it advances or draws
IL


Fig. 2220. PLAN 02 SLIDE-REST.
back the slider, which is guided in a right line by two
pieces of brass on its under side, forming a dove-
tailed groove to which the edges of the frame K are
8 L
8S2
TURNING.
accurately fitted. On this slider a frame or two
rulers area-fixed, with a second steel slider g fitted in
the dove-tailed groove between them, and moved by
a screw 2'. This upper slider has a piece of metal
with a square hole through it, in the direction of its
length, for the reception of the tool .7», and it is se-
cured by a‘ screw at the top. When the slide-rest is
mounted on the bed of the lathe, as in Fig. 2217 , the
upper slider g is parallel with the mandrel, and the
lower one perpendicular thereto. In turning flat or
face-work, the tool is placed as represented. By
turning the screw 11 of the upper slider the tool
advances up to the work, and by means of the other
screw at it can be moved across the face of the work,
thus producing a perfectly flat surface. In turning a
cylinder, mounted between centres, the slide-rest is
moved one-quarter round upon the pin in the socket
s, so that the upper slider will be perpendicular to the
mandrel, and the lower one parallel to it. In such
a case the upper slider must be moved to adjust the
tool to the diameter of the work, and the lower slider
is moved by its handle 03 to carry the tool along the
length of the cylinder. In turning a cone, the plate
or dove-tailed groove, which supports the upper slider
g, is turned round upon the plate 6 e, and fastened at
any inclination by a screw passing through a circular
groove in the plate. In this way the upper slider is
inclined to the mandrel in any required angle, and
will turn a cone either hollow or solid. The sliders
are often divided into inches and parts, by which
means the work can be made to any required dimen-
sions, and articles turned to pattern without difficulty.
The upper slider g has ‘a graduated are for showing
the angle of inclination which it makes with the lower
one when set for turning cones; so that a hollow
cone, being bored out in a chuck, a solid plug may be
bored to fit it withoutany further adjustment.
' In engine—turning, the slider g, Fig. 2220, with the
tool is advanced to the work by pressing it with the
hand instead of the screw. For this purpose the
slider is released from the nut of the screw 2', Fig.
2220, by lifting up a small spring catch 3, Fig. 2217,
the tooth of which enters a notch in the nut, and is
pressed into the notch by a screw Z, by releasing
which, lifting up 3, and drawing back the slider, the
tooth of the catch falls behind the nut of the screw
instead of being in the notch; it thus forms a stop
to check the advance of the tool, but allows it to be
drawn back to clear the work, and also to be pushed
in towards it by hand to cut the line, the stop regulat-
ing-the depth of the line, as the hand can advance the
slider no further when it meets the nut. In this
way a waved line is engraved on the face of the work,
the breadth of the line being determined by the depth
to which the point of the tool is regulated. The
outer waved circle being formed the tool is withdrawn,
and the screw (2 of the great slider turned a small
quantity, so as to bring the point of the tool a little
nearer the centre 'of the work“; by putting up the
tool another line is described; and in this way the
process is repeated until the, lines reach the centre.
As each line has the same number of waves or inden-

tations they become very fine as they approach the
centre; but as the deviation from the circular figure
is equal in the small as in the large rings, the curves
of the waves of each ring or line gradually vary, being
slightly curved near the edge of the work and much
more so towards the centre. This pattern may be
greatly varied by employing different rosettes, fine or
coarse, concave or convex, but the waves will always
be in radial lines. A variation in this respect is
made by turning the rosettes upon the mandrel
through a very small space after the cutting of every
line, a small screw E, Fig. 2217, being provided for
the purpose. Fig. 2216 is an example of this move—
ment; it is a rose of 211 waves: after cutting the
exterior line, and the slider has been set for a second
line, the rosette is turned round upon the mandrel a
quantity equal to i of a wave or glgth of the whole
circle: the circle is then described, and its waves will
not fall into the radial lines of the former, but a little
in advance thereof. The next time a circle is cut
the rosette is again shifted, and so on. As this is a
quantity equal to ;i- of the space between the waves,
the waves of every fourth line will fall into radial
lines. The concentric circles are made at equal dis-
tances by means of the divisions on the slider K, Fig.
2217, or by divisions made upon a head fitting upon
the end of the screw (2, and the rosettes are set
exactly to the quantity they are intended to be
turned round, by means of divisions made upon the
edge of a circular plate fixed upon the mandrel
towards the end of H, Fig. 2217, a line or mark upon
the last rosette applying to it. The screw which
produces the movement is supported in bearings upon
this plate, and acts in the teeth of a wheel fixed
within the hollow of the last rosette. By this means
the screw is turned round by a key, and all the
rosettes are thus made to turn together through any
space, as indicated by the divisions on the circle. It
is surprising what a number of patterns can be pro-
duced by this simple contrivance of shifting the
rosettes in various ways. For example, after having
cut a waved line, the rosette may be advanced half a
division and another line out without altering the
slide-rest. The two waved lines will thus intersect
each other and make a number of loops like a chain
of beads.
In ornamenting the surface of a cylinder, the
slide-rest is turned &- round; by dividing the length
of the cylinder into small equal portions and shifting
the rosettes every time one of these is finished, the
waves may be made to follow each other in a spiral
direction round the cylinder. Some of the rolls used
in calico;-printing are in this way engraved in the
lathe.
There is a movement of the rose lathe called pump-
any, in which the mandrel is made to move endways
upon its bearings, for which purpose the necks upon
which it turns are made truly cylindrical and fitted'
correctly to steel collars fixed in the standards GH.
It can thus slide endways in its collars ,so as to pro-
duce the pumping motion which is given by rosettes
waved upon the edge or side, and acting against the i
TURQUOISE.
883
side of a piece of steel as a, Fig. 2218. A spring 11,
Fig. 2217, is fixed at the end of the frame and acts
against the shoulder of the mandrel, to force it end-
ways, and keep the rosette always in contact with the
piece of steel. The rosettes are cut in waves upon
their sides as well as upon their circumference, and
thus a variety of pumping Zrosettes is obtained. By
this pumping motion waved lines can be out upon the
surface of a cylinder in the direction of its length.
Screw tools formed like a chisel, but with the edge
out with notches so as to present a number of points,
are sometimes used for the sake of expedition, so that
6 or 8 lines may be cut at one operation without
altering the slide-rest after every single line is out.
In cutting swash-work, in which the mouldings or
other lines traced round a cylinder are inclined to
the axis, a steel circle or hoop v, Fig. 2217, is fitted
to the end rosette of the mandrel, so that it can be
inclined from the perpendicular thereto at pleasure.
In this way it forms a guide to the pumping motion.
TURNSOLE. See LITMUS.
TURN-TABLE. See Roxns AND RAILROADS, Fig.
1885-1888.
TURQUOISE, a mineral of a blue or greenish
blue colour, occurring in botryoidal or mammillated
masses, chiefly in alluvial clay in Persia. It has a
conchoidal fracture, and a waxy lustre; it is capable
of receiving a high polish: it is usually opaque, but
sometimes translucent on the edges: hardness 5 to 6,
density 2 8 to 3. It contains phosphoric acid 30'90
per cent., alumina M50, oxide of copper 3'75, oxide
of iron 1'80, water 19. This is the orienlal turquoise:
the occidental or bone turquoise, (which is chiefly
found near the town of Simore in Lower Languedoc,)
is said to consist of bone or phosphate of lime,
coloured with oxide of iron. A specimen analysed
by La Grange contained phosphate of lime 80 per
cent., carbonate of lime 8, phosphate of iron 2, phos-
phate of magnesia’2, alumina 15, water 1'6. Green
malachite is sometimes substituted for the true tur-
quoise ; but it is softer, and has a different tint. The
stone is also so well imitated by the makers of facti-
tious gems, that it is difficult to detect the counter-
feit from the original; the former, however, is much
softer than the latter. -
The mines of the true turquoise are in Khorasan,
at the south-east of the Caspian Sea, in a mountainous
districtfabout 40 miles west of the town of Nisha-
pore. They were visited by Mr. Fraser, some years ago,
and from his notice 1 it appears that the turquoise has
been found only in one hill, and this has been opened
in six places. The first mine does not produce fine
gems; in it is a bed of light grey porphyritic earth,
which is turned over, and pieces of turquoise are
found attached to fragments of porphyritic rock. The
second mine consists of porphyritic rock, tinged with
iron, and containing small veins of blue turquoise
matter, chiefly between the laminae of the rock.
Small pieces of the gem are found adhering to the

(1) Travels and Adventures in the Persian Provinces on the
southern banks of the Caspian_Sea. 4to. London, 1826.

rock, and in some places the turquoise seems to have
bubbled out from the rock in the form of little
pimples of exquisite colour. The third mine was
not worked at the time of Mr. Fraser’s visit. There
was an efflorescence of alum on the face of the rock.
The fourth mine consists chiefly of two deep exca-
vations in a dark brown rock, through which the
turquoise matter is disseminated in small veins.
One of the excavations was full of water, which the
miners did not appear to know how to get rid of. The
fifth and most important mine is near the summit of
the hill; in this the turquoise pervades a porphyritic
rock, and is also found in an imperfect state in a
yellow ochreous clay. In this mine the gem is found
in tolerably symmetrical nodules of different sizes, in
narrow veins pervading the rock, and in irregular
masses, generally of inferior quality. The sixth mine
appeared to be exhausted. The mines are described
as being worked in a very slovenly manner; there are
no shafts or galleries, but each man gropes about
according to his own judgment, and leaves the rub-
bish of the mine in the places where it is produced.
The mines are the property of the crown, and are
farmed out at a sum named by the government. In
1821, it was about 2,7 OOZ. They are generally taken
by the inhabitants of two villages near the mines.
The mode of working is as follows :——100 villagers
take the mines at a price agreed on, and work toge-
ther in parties of 5 or 10, who divide the produce of
their labour collectively or by these separate parties,
each man contributing his share of the rent of the
mines. The produce is sold to merchants who visit
the villages at stated periods, or it is sent to the town
of Mushed for sale. The gems are sold in 3 difl’erent
states. 1. As single stones, freed from the parent
rock and ground, so as to expose the size, shape, and
colour of the gem. 2. Stones freed from the princi—
pal part of the parent rock, the gem being only partially
visible. 3. Masses containing still more of the parent
rock: these are sold by weight.
The stone-cutters reside in Mushed, the chief seat
of the turquoise trade. The stones are ground on
sand laps of different degrees of fineness, turned by
a bow and string, a broad hoop concentric with the
lap preventing the sand and water from being scat-
tered over the lapidary, who holds the gem in his
hand while grinding and polishing. The gems, which
are mostly worked up into rings, are sorted and sent
to different countries. The finest find their way to
India by way of Herat and Candahar. The next in
quality are conveyed westward to Persia and Turkey;
or they are sent to Bokhara, and sold to merchants
who trade with Russia, and thus they gradually get to
Europe. The less perfect gems fetch a much lower
price on account of their being covered with small
white specks; the Arabs, however, do not object to
this defect, as they value the turquoise chiefly for its
reputed talismanic qualities, and they prefer large
stones to purity of colour. The stones intended for
amulets are commonly set in small rings of plated
tin. Professor Fischer notices2 a noble turquoise,
(2) Essai_sur1a Turquoise, 1816.
3 L 2
884
Tunrnnrlnn.
said to have been a talisman belonging to Nadir
Shah of Persia, and containing on its surface a verse
of the Koran beautifully engraved; it was in the
possession of M. W eyer, a jeweller of Moscow, who
demanded 5,000 rubles for it, or about 81%. 108.
sterling. It is described as a thin plate of exquisite
colour; attached to its original matrix, and shaped
into the form of a heart.
In the Great Exhibition there was a collection of
upwards of 200 turquoises made in 1849 by Major O.
Macdonald in Arabia Petraea. We learn from the
Jury Report, Class 1., that he discovered in the
country of Soualby, 16 days’ journey SE. of Suez, 5
or 6 localities in which turquoises existed, all included
within a range of about $0 miles. They are situ-
ated on the further side of a mountain chain, having
an east and west direction, and a mean elevation of
5,000 or 6,000 feet. Most of the specimens were
collected from the ravines descending this chain, but
some were found in sita. The latter were exhibited
attached to a portion of the parent rock, which is
a reddish sandstone composed of quartz grains. The
colour of these tiirquoises differs in the shade of
blue from that of the turquoises of Persia, but agrees
exactly with those brought from Abyssinia by M. R.
d’Héricourt. Both exhibit small globular concretions,
with a hardness equal to that of agate. The nodules
of turquoise form groups almost like currant-seeds in
the sandstone. The intensity of the colour of ad-
iiacent lumps is different, and when the groups are of
tolerably large dimensions, zones of different tints
may be observed. One stone, on caboc/ion, polished
without cutting, was divided into 3 zones, in which
the coloui' varies from an intense blue to a bluish
white. Other specimens exhibited veins of turquoise
from -,*§T,-th'to §15l1h inch thick, cutting across the
bedding (if the sandstone like sinall threads.
TURPENTINE. When trees belonging to the
Conifiiwe or fir—trite, especially the genus Finns, are
wounded in the bark, a balsam exudes consisting of
a mixture of resin and a volatile oil. The latter,
when separated by distillation, is known as spirit or
‘essence q" turpentine or tcrpcntine, and is known in
commerce as tarps or tarps. The source of common
turpentine is Finns sytnestris, and its collection is an
important branch of business in America. “ To
procure it a narrow piece of bark is stripped off the
trunk of the tree in spring, when the sap is in motion,
and a notch is cut in the tree, at the bottom of the
channel formed by removing the bark, to receive the
resinous juice, which will run freely down to it.
As it runs down, it leaves a white matter like
dream, but a little thicker, which is very different
from all the kinds of resin and turpentine in use, and
which is generally sold to "be used in the making of
flambeaux, instead of white bee’s-wax. The matter
that is received in the hole at the bottom is taken up
with ladlesand put into a lai'ge' basket; a great part
of this immediately runs through, and this is the com-
-mon turpentine. It is received into stone or earthen
@pots, and is then ready for sale. The thicker matter
which remains in the basket is put into a common l
‘-
alembic; and a large quantity of water being added, the
liquor is distilled as long as any oil is seen swimming
upon the water. The oil, which is produced in large
quantities, is then separated from the water, and is
the common oil or spirit of turpentine. The remain-
ing matter at the bottom of the still is the common
yellow resin.”1 According to another account, the
collection of turpentine in the United States is con-
fided principally to negroes, each slave having the
charge of from 3,000 to 4,000 trees. The process
is continued through the year, but the incisions are
not made in the trees until the middle of March, and
the flow of turpentine generally ceases about the end
of October. The formation of the cavity at the root of
the tree is called toning, and the turpentine which
flows into it is known in commerce as pure (Zipping,
Each box holds about apint and a hall", and is‘emptied
5 or 6 times during the season: {it is estimated that
250 boxes will produce a barrel weighing 320 lbs.
The deposit made by the sap on the bark of the tree
is called scraping, and is collected in autumn, The
quantity of turpentine imported into the United
Kingdom in the year ending 5th January, 1853,
amounted to 4181,616 cwt. i’ _
There are other kinds of turpentine. That known
as Venice, Strastarg, Swiss, or taro/71. turpentine is
obtained from the Laria: Earopaa. It is a clear,
colourless balsam, containing from 18 to 25 per cent.
of the oil. It has a tendency to thicken or splidify.
Professor Brande states that the‘ article usually sold
under this name is factitious, and is made by fusing
a pound of resin with about 5 ounces of oil of turpen-
tine. There is a thinner Strasbaiy turpentine from
Finns picca; containing 33 per cent. of oil. Canadian
turpentine or Canada batsagn, the purest of all the
pine turpentines, is obtained from Aliz'cs batsamca in
Canada. In its fresh state it has the consistence of
honey, an agreeable odour, and a bitteris’h taste; it is
of a yellow transparent colour: it solidifies on being
kept. C/tian turpentine is obtained from the turpen~
tine tree, Pistacia tcrcbintlins, a native of Barbary
and the south of Europe; this turpentine has a
highly aromatic flavour. Common firm/cinccnsc is an
exudation of Abies conznznnis. The Carpathian and
Hangarian varieties of turpentine are from .Pinas
cembra and mayo. 7 |
The balsam obtained by tapping pine-trees is, as
already stated, a solution of resin in oil of turpentine,
which substances have so close a chemical relation
that the resin is produced from the turpentine by
simple exposure to the atmosphere. Oil of turpen-
tine is regarded as a compound of a carbo-hydrogen
with hydrogen, or CmHw-l-H, in which case resin
is formed by the abstraction of the single equivalent
of hydrogen by the oxygen of the air, water being
produced, and the substitution of another equivalent
quantity of oxygen in its place. The resin of turpen—
tine is a mixture of two substances of this kind, and
is similar in composition to sytvic and pinic acids,
(320111502. ‘
_, -0

(1) London, “Arboretum Britannicum.”
I
TURPENTINE.
est
" The different varieties of turpentine above enume:
rated, consist of different proportions of oil and
resin. Common turpentine contains from 5 to 25
per cent. of the oil. When this dries up or hardens
into resin on the trees it is called pine~rcsin, or white
resin; it contains about 10 per cent. of the oil; it is
hard 011 the outside, soft within, and it admits of
being kneaded. WVhen melted and drained from the
particles of wood, 850., the residue is BaipnncZypitc/t,
or colzclefs-zoaaz.
As the oil of turpentine is of much greater value
than the resin, it is separated by distillation in a
copper retort, with about one-fourth part of water.
When no more oil and water pass over, the melted
resin is drawn off and strained. It cools into a
brown, transparent, brittle mass, more or less dark in
colour, according to the extent to which the distilla-
tion has been carried. It is called coloplzonp. At the
temperature of 156° F. it is sufficiently soft to be
kneaded: at 275° it is completely fluid. When
heated out of the presence of the atmosphere, it
evolves gas, a combustible oil, and an acid water.
[See Gas, Fig. 1050.] The density of colophony is
107 to 108: it consists essentially of pinic acid
mixed with a little sylvic; its dark colour is traced
to pinic acid, which is readily decomposed into
another resin~acid, the coloplzonic. Cobbler’s wax is
formed artificially, by fusing 3 parts colophony and
1 part of white resin.
Oil of turpentine obtained by the above process of
distillation, is rectified by mixing it with a solution
of caustic potash, and redistilling. The product
forms rectified oil of turpentine or camp/zinc ; but to
obtain it perfectly pure, it must be again distilled
with water, and lastly with chloride of calcium.
Thus purified, oil of turpentine is a limpid colourless
liquid, with a hot taste, and a peculiar odour; its
density at 60° is 0865 to 0870: it boils at 31?,
and the density of its vapour is $764. It is almost
insoluble in water, and only slightly soluble in spirits
of wine. It mixes readily with the fixed oils. It is very
inflammable, and burns with a very sooty flame; but
if well supplied with air, the flame is very brilliant,
and emits no smoke. [See LAMP, Fig. 127 0.] The
oil thus burned should be pure and freshly distilled,
and exposed to the air as little as possible. As oil of
turpentine is very inflammable it should not be pre-
served in wooden casks, (on account of the liability to
leakage,) without the precaution of placing each cask
within another containing water.
Oil of turpentine is largely used in thejarts. See
PAINTING—VABNISH.
When rectified oil of turpentine (not made anhy-
drous) is kept for a long time in bottles, their interior
is sometimes studded with groups of beautiful,
colourless, prismatic crystals, having the composition
of a lzyclrate of oil of turpentine, and containing
C201116E:60(5'
Oil of lemons has the same composition as oil
of turpentine, although so dissimilar in odour. The
oils of orange-peel, bergamot, pepper, cadets, janiper,
capicz', clean’, the laarel- oil of Guiana, and the grass-

‘oil of the East Indies are hydrocarbons ‘isomeric with
oil of turpentine. , . '
Strong sulphuric acid chars and blackens oil of tur-
pentine ; concentrated nitric acid and chlorine act
with such energy on it as to _set it on fire. With hy-
drochloric acid it forms a substance called artificial
camp/tor, from its resemblance to that substance. It
is formed by passing dry hydrochloric acid gas into
the pure oil kept cool by a freezing mixture. Awhite
crystalline substance separates, and on straining off
the supernatant brown acid liquid, it may be purified
by alcohol, in which it dissolves readily. It is neu-
tral to test paper; it sublimcs without much decgmpc-
sition; it consists of CQOIIWCI, or CQOHIBHCI. The
dark mother liquor contains a similar bnt fluid com-
pound. These substances are furnished in very diffe-
rent quantities by different specimens of oil of tur-
pentine. I'Vhen decomposed by distillation with lime,
they give oily products similar in compositiop to qil
of turpentine, but possessing certain distinctiye prg;
perties. That from the solid aytifipial cainpliqr i§
named campln/lene ; and that from the liquid, teredy;
lcne. Another isomeric compound, termed colopkene,
is formed by distilling oil of turpentine with cdncenl
trated sulphuric acid; it is a viscid, oily, colourless
liquid, boiling at a high temperature: by reflected
light it has amdeep bluish tint.
The countries which supply turpentine, _fjirnish also
that very important substance tar. The prpcess of
tar-making in the north of Europe is thus described
by Dr. Clarke :—~“ The inlets of the ,Gulf of Bothgig
are surrounded by noble forests, whpse tall tree§,
flourishing luxuriantly, cover the soil quite down t9
the water’s edge. From the most southern parts ‘(if
l/Vestro-Bothnia to the northern extremity of Gulf, the inhabitants are occupied in the ingiiufaptprg
of tar, proofs of which are visible in the whole ex-
tent of the coast. The process by the tap obtained, is very simple. The situation mgst favour;
able to the process is in a forest near to_ a qr
bog, because the roots of the fir, from which ta; is
principally extracted, are always most prodgctiye in
such places. A conical cavity is made in the ground,
(generally in the side of a bank or sloping hill) ; and
the roots of the fir, together with logs and billets 9f
the same, being neatly trnssed in a stack 9f the same
conical shape, are let into this cavity. The whole is
then covered with turf, to prevent the 1golatile parts
from being dissipated, which, by means of a heavy
wooden mallet and a wooden stamper worked sepa_
rately by two men, is beaten down and rendered as
firm as possible above the wood. The stack of billets
is then kindled, and a slow combustion of the fir
takes place, without flame, as in making charcoal.
During this combustion, the tar exudes; and a cast-
iron pan being at the bottom of the funnel, with a
spout which projects through the side of the bank,
barrels are placed beneath this spout to collect the
fluid as it comes away. As fast as the barrels ,are
filled they are banged and made ready for expqrta;
tion. From this description it will be evident thgt
the mode of obtaining tar is by a kind of distillation,
886
TUTENAG—ULTRAMARINE.
per (Zescerzsum : the turpentine melted by the fire,
mixing with the sap and juices of the fir, while the
wood itself becoming charred, is converted into char-
coal.”
This method of making tar was practised by the
ancient Greeks, and is described by Theophrastes and
Dioscorides. Dr. Clarke remarks that “there is not
the smallest difference between the tar—work in the
forests of Westro-Bothnia and those of ancient
Greece. The Greeks made stacks of pine, and having
covered them with turf, they were suffered to burn in
the same smothered manner; while the tar melting,
fell to the bottom of the stack, and ran out by a
small channel cut for the purpose.”
l A more recent observer, Mr. Iiaing,1 states that
those “ fir-trees which are stunted, or from situation
not adapted to the saw-mill, are pealed of the bark a
fathom or two up the stem. This is done by degrees,
so that the tree should not decay, and dry up at once,
but for 5 or 6 years should remain in avegetative
state, alive but not growing. The sap thus checked
makes the wood richer in tar; and at the end of
6 years, the tree is cut down, and is found converted
almost entirely into the substance from which tar is
distilled. The roots, rotten stubs, and scorched
trunks of the trees felled in clearing land, are all used
for making tar. In the burning or distilling, the state
of the weather, rain, or wind, in packing the kiln,
will make a difference of 15 or 20 per cent. in the
produce of tar. The barrels containing tar are
always very thick and strong, because on the way to
market, they have often to be committed to the stream
to carry them down the rapids and waterfalls. The
price is only 6.9. 8d. sterling to the peasant, and often
not so much. Those who follow tar making are
always the most indigent.”
TUTENAG, an'alloy of 8 parts copper, 3 of nickel,
and 6% of zinc. It is a very hard, fusible alloy, not
easily rolled, and is best adapted for casting. It
sometimes contains a small proportion of iron.
TYPE. See PRINTING, Sect. II.
’ ULTRAMABINE, a beautiful blue pigment, so
called because it is said to have been brought from
beyond the sea, from the island of Cyprus, or because
it is bluer than the sea. It is obtained by isolating
the colouring matter of lapz's lazuli, or lazulite, a
mineral of indeterminate composition, as will be seen
from the following analyses, the first of which is by
Gmelin, and the second is quoted by Dana :—

Silica 49 45'5
Sulphuric acid.............. 2 ............. .. 5 9
Alumina...................... 11 .. 31 8
8 . 9'1
16 ............. .. 3'5
ltlagnesia ................... .. 2 Chlorine 0'4
Peroxide of iron............ 4 Iron .... .. 0'8
Sulphur a trace 0'9
a trace .. 0'1
92 980
Lazulite is found chiefly in granular limestone, near
granite, as on the shore of Lake Baikal. It is mostly
brought from China, Thibet, and especially from

(I) Tounin Sweden in 1838.

Badakschan, in Tartary. It often contains scales of
mica and iron pyrites. It is found in masses more or
less pure, generally in small volume, fragile, but
capable of scratching glass, of granular texture, im-
perfectly laminated, and almost transparent at its
edges. It crystallizes in dodecahedrons with rhombic
faces, but the crystals are rare. Its density is 2'5
to 296. The colour which occurs in isolated spots
passes from celestial blue to pure blue and indigo
purple. It is usually disseminated in a rock which con-
tains many other laminated substances, among which a
white lazulite has been named? The iron pyrites some-
times disseminated in lazulite are of a golden yellow
colour, and help to relieve the lustre of the blue;
these pyrites have been mistaken for pellets of gold.
The mineral is known in commerce as Zapz's, more
or less rich in lazulite; it sometimes contains only
one-third or one-fourth of the valuable mineral. The
finest specimens of lazulite are reserved for jewellery,
and for Florentine mosaic. The less rich specimens
are used for decorating apartments. The walls of the
palace of Orlofi’, at Petersburg, are said to be covered
entirely with lazulite of Great Bokhara. The ancients
worked in this stone: many antique engravings, hol-
low or in relief, are extant; but the ancients do not
seem to have known the art of separating the ultra-
marine which constitutes the chief value of lazulite.
Before the blow-pipe, lazulite loses its colour, and
changes first into a grey enamel, and thence into a
white. In hydrochloric acid lazulite speedily loses its
colour, and forms a gelatinous solution with the evo-
lution of sulphuretted hydrogen.
Not more than from 2 to 3 per cent. of the finest
ultramarine can be separated from the best lazulite.
The method of doing this is so very tedious, and the
destruction of lazulite so large, that the cost to the
artist of ultramarine may be as much as 20 guineas
per ounce.3 In order to separate the colouring mat-
ter the lazulite is first ground with water on a hard
stone of fine grain, and the powder thus produced
being dried by exposure to the air, is kneaded up
into a dough with a resinous composition called pea
tel/0, composed of linseed-oil, wax, and resin or pitch,
and the mixture is left to consolidate during 8 or 10
days. The dough is then washed in warm water
until the water begins to appear blue; this is done 3
times, each water being kept separate. From each of
the coloured waters ultramarine subsides in a powder,
which is different in each case in beauty and brilliancy
of colour.
Another method is to raise the lazulite to a red
heat, and then to quench it in strong wine-vinegar:
the vinegar is next to be poured off, the stone dried
and pounded. The powder thus produced is to be
ground on a stone with a muller and water until it is
quite impalpable. It is to be dried in the sun or in

(2) In the Musée Minéralogique, at Paris, are two crystals of
lazulite, in which may be seen the transition from the blue to the
white variety.
(3) Messrs. Newman of Soho Square have allowed us to
examine their stock of genuine ultramarines, some of which have
been sold at this price.
ULTRAMARINET *
as?)
a warm room, and made up into a dough with a mix-
ture of linseed-oil and strong brandy. The dough is
to be rolled out into a cake, spread upon a clean
broad plate, and covered with paper smeared with
linseed oil to keep off dust: in this state it is to be left
in a damp place, such as a cellar, for 11 days. The plate
with the dough is next to be placed in a sloping posi-
tion in a basin of glazed ware, capable of holding 8 or
9 quarts of water. The plate being held in the left
hand in the sloping position, a stream of clear water
is to be allowed to fall upon the dough, while it is
being worked up with a spatula held in the right
hand of the operator; in this way the ultramarine
becomes loosened, and flows away with the water.
When the basin is half full, another basin is selected,
and the operation proceeded with. A third and a
fourth basin are also used, and in this way four differ-
ent kinds of ultramarine are obtained, that in the first
basin being the finest. The dough is then again
kneaded, and returned to the cellar for 8 days. In
the meantime the basins are covered up to keep out
dust, and in the course of 24 hours the colour is de-
posited. The water is gently decanted ofi' into other
basins so as not to disturb the deposit. Each deposit
is washed 5 or 6 times with clean water in order to
detach portions of oily or resinous matter which came
over with the colour: these are picked out separately,
or they are burnt away by raising the precipitate to a
red heat: the ultramarine, on cooling, regains its
beautiful blue colour, but the quality suffers some-
what in this process, and it requires a diligent por-
phyrisation to restore it to its first quality. All the
waters used for washing the precipitates are set
apart, and are afterwards treated for different kinds
of inferior ultramarine. The original cake having
been left in the cellar for 8 days, is again put into the
bowl as before; warm, but not boiling water, is
poured over it, and it is washed or kneaded by hand
instead of with the spatula. When the water becomes
coloured it is poured into another bowl, and the pro-
cess is repeated so long as the water is coloured.
The precipitates at the bottom of these bowls are
washed 3 times, dried, and extraneous matters picked
out. Lastly, the cake, or the remaining dregs of it,
is washed with warm lye, when a bluish grey precipi—
tate is produced, which, when washed, dried, and
picked, forms what is called allmmcrz'ne as/z.
Ultramarine is estimated by its brilliant colour and
impalpable state of comminution. The former quality
depends, to a great extent, upon the latter, and this
can only be secured by thoroughly grinding the lazu-
lite. The state of comminution is judged of by taking
some of the ultramarine into the mouth. If it feel
sandy, and grate between the teeth, its quality is not
good; but if it behave like flour or well-bolted meal,
it is of good quality, provided, of course, that the
colour be brilliant. The best test of its being genuine
is to heat it to redness; if its colour does not change
it has been prepared from oriental lazulite: if it be-
comes green in the fire it is of inferior quality, and
has been prepared from occidental lazulite. The colour
known as azure-clue is prepared from the latter, but

it changes to green in the course of time, as may be
noticed in those pictures of the old masters in which
genuine ultramarine has not been used.
Such is the apparently complicated process for ob-
taining genuine ultramarine. It has probably been
practised from the lélth century, and was not of
course founded upon any chemical analysis of lazulite;
yet how completely it answers the purpose intended!
It was first remarked by Clement and Désormesjl that
the waters employed in separating the ultramarine
from the pastello were soft and unctuous to the
touch like w'eak alkaline leys; and they actually ob-
tained an alkaline residue on evaporating these waters.
Hence the theory of the process is simple. It appears
to be based on this circumstance, that the oil of the
pastello unites with the ultramarine of the lazulite
(which we have seen contains soda), and forms a kind
of soap therewith which is readily soluble in tepid
water; while the gangue or stony portions of the
lazulite, not containing soda, do not form any such
soap, but remain entangled with the insoluble wax
and resin of the pastello on which water has no sort
of action. A more simple and beautiful contrivance
for separating the minute portions of ultramarine
from lazulite can scarcely be imagined.
The specific gravity of ultramarine is 2360, water
being 1000. If the mastic has not been entirely
removed, ultramarine can be fused at a very high
temperature into a black enamel; but, if quite pure,
the ultramarine forms an almost colourless glass.
Heated with borax, it readily forms avery transparent
glass; it disengages sulphur and a little carbonic
acid, the quantity of which varies with the quality of
the ultramarine. Ultramarine is decomposed by dilute
sulphuric and hydrochloric acids, sulphuretted hydro-
gen being given off. When nitric acid is added to
ultramarine both are decomposed, and red fumes of
nitrous acid appear. In this way ultramarine can be
readily distinguished from smalt. [See Conann]
Acetic acid acts more feebly. Hydrogen gas passed
over ignited ultramarine colours it light-red from
the formation of liver of sulphur, sulphuretted hydro-
gen and water being evolved. By passing oxygen gas
over it at a red heat the colour is changed to green.
‘When solutions of potash or soda are heated with
ultramarine, alumina is abstracted therefrom, but the
colour is not altered; but caustic potash, heated with
ultramarine, destroys its colour, and a reddish mass
remains. Ammonia has no action.
The high price of ultramarine, and the unexampled
effects which it produces in painting, rendered it very
desirable to produce this substance artificially. Se-
veral 'of the most illustrious French chemists made
the attempt at the commencement of the present cen-
tury. They were for some time bafiled by the discor-
dant results obtained by analysis, and were unable to
distinguish which of the ingredients of ultramarine
were essential, and which accidental or superfluous.
Thus, in a paper read before the National Institute
in 1800, by the citizen Guyton, the opinions of ether

1) “ Annales de Chimie,” 1806.
ass
ULTBIAMARINE.
chemists are referred to. Eefore the analysis by
Margraf the colour of ultramarine had been attributed
to, the‘ presence of copper; but that chemist found
only silica, sulphate of lime, lime, and a little iron,
resent. Others suspected the presence of oxide of
cobalt: others, again, fiuoric acid. Klaproth’s ana-
lysis gave silica 46 per cent, carbonate of lime 28,
alumina 1465, sulphate of lime 6'5, oxide of iron 3,
and water 2. Guyton thought that the colouring
matter was a blue sulphuret of iron, and that ultra-
marine might be produced artificially by combining
sulphuret of iron with certain earths.
- In 1806, Clement and Désormes published an
analysis of ultramarine: they admit the difficulty of
the analysis of this substance, but are disposed to
regard it as being composed of silica 358 per cent.,
alumina 34:’8, soda 23'2, sulphur 3'1, and carbonate
of lime 8'1 . -.
‘ The first step towards the production of artificial
ultramarine was made in 1814, when Vauquelin, in
visiting the plate—glass manufactory of St. Gobain,
was infonnied by M. Tassaert (the director of the sul-
phuric acid and soda department of that establish-
ment), that in taking down the soda furnaces a blue
substance was found, when grit-stone (gres) was used
in the construction of the sole, but that there was no
such deposit when the sole was of brick. The sub-
stance in question was similar to lapis lazuli. On
reducing it to powder, and washing it, Vauquelin
found that it was discoloured by the mineral acids
with the disengagement of sulphuretted hydrogen;
that it was not attacked by boiling alkaline solutions,
nor destroyed at a red heat. Vauquelin states, that
although the composition of this artificial product is
unlike that of lapis lazuli, yet he is not without a
hope that this'circumstance may lead to the produc-
tion of Ultramarine artificially. it
This observation, and the suggestion founded upon
it, appear to have been forgotten for nearly 14: years.
In March, 1828, Gmelin of Tubingen published in the
Hcspcrns, No. ‘7 6, an analysis (which we have already
quoted) of lapis lazuli from St. Petersburg, and of
riltramarine from the best makers in Paris, and also
a sample from Professor Oarpi of Rome. This was
found to contain soda 1206 per cent, lime 1'55,
alumina 22, silica 47'31, sulphuric acid £68, sulphur
0'19, water, resin, &c. 12'31. Gmelin states that the
analysis by Olément and Désornies is calculated to
lead to error : he suggests that sulphur is the colour—
ihg material of ultramarine, and after referring to
Tassaért’s observation, states that he had succeeded
in producing ultrainarine artificially, but that the
honour and profit of the discovery were lost to him
in consequence of his having been so indiscreet as to
inform Gay Lusrsac and other chemists in Paris in
the previous year (1827), that he was engaged in the
attempt to produce this pigment by artificial means.
On the 43th Feb. 1828, Gay Iiussac announced to the
Academy of Sciences at Paris, that M. Guimet had
succeeded in making ultramarine, but that at present
he wished to keep his process secret. Gmelin infers
that this announcement would not have been made

had it not been for the hint which he gave to Gay
Lussac. He then proceeds to justify his claim to the
discovery by publishing his process. Hydrate of
silica and alumina are prepared, the first by fusing
well-pulverized quartz with A times its weight of car-
bonate of potash; the fused mass is to be dissolved
in water, and the silica precipitated by means of by
drochloric acid. The alumina is prepared by preci~
pitating a solution of a pure salt of alumina by means of
ammonia. The two earths are to be carefully washed
with boiling water, and the quantity of pure earth is
to be determined after heating to redness a certain
quantity of the moist precipitate. The hydrate of
silica employed contained, in 100 parts, 56 of anhy-
drous silica, and the hydrate of alumina 8'24 parts.
Dissolve with heat, in a solution of caustic soda, as
much of this hydrate of silica as it can dissolve, and
determine the quantity of earth dissolved. For '72
parts of this anhydrous silicate take such a quantity
of hydrate of alumina as contains 70 parts’ of dry
alumina. Add it to the solution of the silica and
evaporate, stirring it constantly, until a moist powder
only remain. This compound of silica, alumina, and
soda, forms the base of ultramarine, and it is to be
coloured by the addition of sulphuret of sodium; for
which purpose a mixture of 2 parts sulphur and 1 part
anhydrous carbonate of soda are to be gradually
heated in a Hessian crucible with a well-fitting cover,
until the mass is well fused. This sulphuret is to be
projected, in very small quantities at a time, into the
fused compound of silica, alumina, and soda. As soon
as eifervescence ceases, another portion of the sul-
phuret is toube added. The crucible containing the
preparation is to be kept at a moderate red heat for
one hour, and is then to be removed from the fire
and allowed to cool. It consists of ultramarine, with
an excess of the sulphuret which is to be removed by
the action of water. If sulphur now be in excess it
may be expelled by the application of a moderate
heat. It the mass of ultramarine be not equally
coloured throughout, the finest parts may be separated,
and reduced to a very fine powder by washing with
water.
A translation of this paper in the Hesperus from
German into French was’ made by Liebig, and f0r~
warded to Gay Lussac, who, in one of the parts of the
Annales de Chimie et de Physique for 1828, ad:
mitted that Gmelin did inform him that he believed it
possible to make ultramarine artificially, but that he,
Gay Lussac, was not aware that any one in Paris was
engaged in the attempt to form it; that lGuimet’s
experiments were conducted at Toulouse, and that
Gay Lussac only knew of them in consequence of
having received a specimen of ultramarine from
Guimet 6 weeks before, and that he had announced
the important discovery to the Institute. As to the
priority of the idea, no one could seriously think of
appropriating that, after Tassaert’s observation; but
that if the question of priority were raised, then it
must be claimed by the ‘-‘ Société d’Encouragement,’
' &c. of Paris, who, 4. years before, had offered a prize
of 6,000 francs for the manufacture of artificial ultra.
a,
ULTRAMARINE.
8'89‘
marine} a sufficient proof that the Society thought
its artificial production possible. Gay Lussac adds a
note from Guimet, who states that at the time when
Gmelin made his indisereet communication at Paris
in the spring of 1827, he, Guimet, had, a year before,
produced artificial ultramarine at Toulouse, that he
had been long occupied. in the attempt to make
his process economical and applicable to the Arts.
In July, 1827, his blue was in the hands of several
distinguished artists, one of whom he names, who
spoke of it in the highest terms. Guimet defends the
analysis of Clement and Désormes, and states that
they found 3 parts of sulphur in 92 in all the speci-
mens which they examined. He admits that Gmelin’s
recipe for the production of artificial ultramarine may
be of importance to science, but not to the useful arts‘,
on account of its eostliness and tediousness.
It will be observed that, in Gmelin’s process, ex-
treme care is taken to insure the purity of the ingre-
dients. This does not appear to be necessary. Indeed,
we have been informed, that one chemist, in repeating
Gmelin’s process, failed, and had actually abandoned
the experiment, when one of his assistants tried the
effect of stirring the contents of the crucible at a low
heat: he used for the purpose an iron rod, and was
surprised to see the green powder change into a bean-
tiful blue. This was attributed to the introduction
into the composition of a small portion of iron from
the stirrer, and some authorities maintain that, from
0'9 to 1 per cent. of iron is necessary to the produc-
tion of the _colour.
In1830 we find another notice of the accidental
formation of artificial ultramarine. M. Kuhlmann
states, in the Annales de Ghimie, 850., vol. xl., that
in repairing a reverberatory furnace used for calcining
sulphate of soda in the manufacture of soda from
common salt, the brick fire~bridge was found to be
covered in seyeral places with a deposit of ultramarine.
It appears that, previous to the formation of this de-
posit, sulphuret of sodium, in small brilliant crystals
of a brownish red colour, had been formed. M.
Kuhlmann attributes the formation of the ultramarine
to the action of the soda and sulphuret of sodium on
the silica and alumina of the bricks.
In May, 1831, Guimet addressed Gay Lussae, and
reported the progress of his valuable discovery. He
refers to the importance to the arts of being able to
supply ultramarine of good quality at a low price, as
it is so eminently calculated to take the place of
cobalt-"blue in painting, and of pxide of cobalt or smalt
in colouring glass. Enormous quantities of this
colour were used for colouring paper, woven fabrics,
and other manufactures, at a price varying from 2'7 5
to 3 francs per lb. There was no doubt that the
artist would prefer artificial ultramarine to cobalt-
blue, but for common purposes it seemed scarcely
possible to manufacture ultramarine at a cost suffi—
ciently low. Montgolfier, the celebrated paper-maker,
found that 11b. of artificial nltramarine produced the
effect of 101bs. of the finest smalt, and produced a more

(i) This prize was awarded to Guimet in 1828, on which occa-
sion he communicated his process confidentially to Gay Lussae. ‘

'uniform tint. The price first'charged by Guiniet for‘
common Ultramarine, was 20 francs per 1b., which, after
9 months’ demand for the article, he was enabled to
reduce to 16 francs. The first quality for artists was
charged’ 60 francs per 1b., and a second quality 20
francs. As Lyons was likely to use a good deal of
the ultramarine, Guimet established his factory three
leagues from that city, and expressed his hope that
France would soon be independent of Germany for
the supply of blues except cobalt blues for the pur-
poses of pottery and porcelain. _’
We are not aware that Guimet has ever published
his process. Previous to the year 1847 there was only
one manufaetory in France in addition to Guimet’s,
viz. that of Courtial. In Germany, Leverkus was
known as a maker. In that year Zuber 85 Go. of:
Rlxheim, in France, commenced operations, and after;
this a number of manufaetories, twenty at least, were
established in some of the small towns on the banks
of the Rhine and elsewhere, and many processes for
the manufacture were published: Gmelin published
an improvement on his first process : Persoz of Stras-
burg, and Kottig, director of the Saxon Ultramarine
Works, have also given processes. We will give one
or two that have been published. The reader who
desires more, will find them in the works mentioned
below.2 ‘ '
Kressler states that a mixture of 1 part of clay,
perfectly free from iron, with 1 part of sulphur and%
parts of anhydrous carbonate of soda, yields a yellow-
ish mass when ignited; but, that if a trace of sulphate
of iron be added to the mixture, a mass is obtained
which is black, green, or blue, according to the de-
gree of heat to which it has been subjected. Gmelin
states, that when potash is used, instead of soda, the
blue colour is not obtained.
Professor Brunner, in repeating Gmelin’s process,
always obtained a product very inferior to the natural
product; but at length he obtained a satisfactory re-
sult by using a peculiar sand found near Longnau in
the canton of Berne, containing 94'25 per cent. of
silica, 3'03 of alumina, 1'61 of lime, and 0'94: of ses-
quioxide of iron. An intimate mixture is made with
70 parts of this sand, washed, 240 parts of burnt
alum, 4.8 parts of powdered charcoal, 144: of flour
of sulphur, and 24.0 of anhydrous earbpnate of soda,
all reduced to an impalpable powder. The mixture is
introduced into a Hessian crucible, and the cover luted
down. The crucible is then exposed to a moderate
red heat kept as steady as possible for an hour and a.
half, after which it is suffered to cool. If the ope-
ration has been successful, the mass presents a loose,
semifused appearance, and a greenish or reddish-yellow
liver of sulphur colour; it is also reduced to about
‘glths of its former volume. (If it appears solid, fused,
browner in colour, and of still smaller bulk, the tens-1
perature will have been raised too high.) The mass,
which is readily detached from the crucible, is put
into a dish and washed with either hot or cold water,

(2) Gmelin, “ Hand Book of Chemistry,” vol‘. Qavendish
Soeiety’s Translation, 1849. “ Pharmaceutical Journal,” vols. vi.
“ Chemical Gazette,” vols. i. -~
890
ULTRAMARINE—UMBER—URANIUM.
until the liquid has no longer asulphurous taste. The
residual dark-greenish blue powder is then thrown on
a filter and dried. The dry powder is next mixed
with an equal weight of sulphur and 1%,— times its
weight of anhydrous carbonate of soda, and treated as
before. The resulting mass, after washing and dry-
ing, is once more heated with the same proportions of
sulphur and carbonate of soda, the product boiled for
some time with water, and then thrown on a filter
and washed with cold water until the liquid which
passes through ceases to colour acetate of lead. The
powder, after being dried, is passed through a fine
sieve to separate impurities, and then treated as fol-
lows :--A cast-iron plate, or platinum dish, is covered
with a layer of pure sulphur, about a line in depth,
and on this about the same quantity, or a little more,
of the perfectly dry compound is sifted. The plate is
then carefully heated until the sulphur takes fire, the
compound itself being kept from ignition as much as
possible, (or the preparation may be mixed with
half its weight of sulphur, and cautiously heated as
before.) This process is repeated 3 or ‘1 times, the
residue on each occasion being detached from the
plate and reduced to powder. The operation is re-
peated until a satisfactory colour is obtained.
Brunner is of opinion that the presence of lime
is of little importance in the preparation of ultra-
marine, and that iron is not important; that the blue
colour depends on the soda, for if the above process
be carried out with potash instead of soda, an analo-
gous compound is produced, but it is perfectly white.
If the burning process with sulphur be continued after
the compound has attained its finest colour, a point is
reached at which it ceases to increase in weight; but
if it be then heated without the addition of sulphur,
an increase of weight is again observed, and a mass
obtained having a paler blue colour with a tinge of
black, resembling that of some varieties of native
ultramarine. The powder, at the same time, loses
its soft, loose texture, and becomes denser and gra-
nular, in which state it does not evolve sulphuretted
hydrogen with hydrochloric acid, showing that it con-
tains no unoxidized metallic sulphuret.
In the Great Exhibition, M. Guimet appeared as
the most successful manufacturer of artificial ultra-
marine, “his product being remarkable for the inten-
sity of its hue, and standing well the dilution with a
white powder, which is a most trying test of that pro-
perty. It appeared to the Jury, assisted in the depart-
ment of colours by Mr. Linton, who, as an artist, has
made the chemical properties of colours a peculiar
study, that for use in oil and water-colour painting,
a pure blue ultramarine, unmixed with red, is desired;
while, on the other hand, the ultramarine is recom-
mended by its purple bloom as a colour upon cloth.
The specimens exhibited generally possessed the latter
character, and were no doubt chiefly intended for
calico-printing. The discovery of a method of attach-
ing this insoluble pigment to cloth by means of albu—
men, which is ultimately coagulated by heat, com-
bined with the low cost of production, has led to a
great demand for ultramarine and rapid extension of

the manufacture within the last few years. Certainly,
many of the finest effects in the beautiful prints, at
present exhibited, are produced by its means.” 1
The quantity of ultramarine produced in France in
18448, in three manufactories, is estimated at from
90,000 to 100,000 kilogrammes; and for 1851, in
four manufactories, from 150,000 to 170,000 kilogs.;
the price of the finer sorts having fallen during the
same period from 9 to 550 francs per kilog. A green
ultramarine has been introduced for printing on
cotton and paper, and it has the advantage over
arsenical greens in not being poisonous nor alterable
by alkalies.
The difierent varieties and shades of colour of arti—
ficial ultramarine are very numerous. The Rheinischc
Ultramarine Factory of Wermelskirchen exhibited no
less than 60 distinct varieties, each of which had its
own peculiar mark or brand, as follows :--
1. o,BsF 16. 0,14. 31. an “ 46. 3E
2. 0,1sF 17. 1 32. 4B 4?. in
a o,BsF 18. OSF as. 55 4s. 2s
4. o,ss 19. 10S]? 54. e 49. A
5. o,sr 2o. zosr 35. 4 50. n
e. o,AsF 21. DlB as. 5 51. BA
7. me 22. mo 37. 7 52. D
8. SF 23. 3815‘ 38. 0,14. 53. 1B
9. 1F 24. o 39. 0,11. 54. F
10. rs 25. 10 40. em 55. 2
11 2FS 26. 20 41. DR 56. 5N
12 0,0 27 30 42 lDR 57. 3A
13 0,, 28 0,13 43 4E 58 6M
14 0,13 29 DOB 44 2DR 59 4A
15 o, 30. o, 45. n so. 7N
UMBER, an ore of iron and manganese, said to
consist of oxide of iron 48 per cent., oxide of man-
ganese 20, silica 13, alumina 5, and water 14. It is
found in beds with brown jasper in the Island of
Cyprus. It occurs massive and amorphous : its
structure is earthy, its fracture conchoidal ; it is soft
and opaque; its colour is blackish, reddish, or yel-
lowish brown; it adheres to the tongue, and falls to
pieces in water: its density is 2206. It is used as
a brown pigment, and is also employed to make var-
nishes dry quickly.
UNIVERSAL JOINT. See COUPLINGS, Fig. 676.
URANIUM, U.60., a scarce metal, found chiefly in
pec/zblende, which is an impure oxide, and also in com-
bination with phosphoric acid in nmnz'fz'e mice. A
native oxide and a sulphate also occur, but rarely.
The metal can only be obtained by means of potas-
sium, as in the preparation of magnesium, which see.
It is a black coherent powder, or a white malleable
metal, according to the state of aggregation. The
protoxide, UO., is a brown powder, but sometimes
crystalline: it forms with acids a series of green salts.
The deutozrz'rie or black oxide, U405, does not form
salts. The peroxide, U203, is the most important; it
forms a number of yellow salts of great beauty. This
oxide is used to impart a delicate yellow and a greenish
yellow colour to glass. The green oxide, U304, or the
deutoxide, is used to produce a black on the Berlin
porcelain ware. Some of the salts of this metal would
probably afford pigments, and be useful in calico-
printing, if the metal were more abundant.
(1) Jury Report, Class II.

VALERIAN—VANADIUM—VANILLA.
89].
VALERIAN, a plant belonging to the genus Vale-
rimzc, the type of the natural order Vclerz'anaeeee, of
which the species V. ofiicz'nalz's, the ofiicivzal, or great
wild Valerian, is used in medicine, the root, or, more
properly, the rhizoma, with its root fibres, of the
variety sylceslrz's, being the part employed. The root
has a peculiar odour, which is due to a volatile oil,
which passes over on distilling the root with water.
The oil is a hydrocarbon, containing CmHs. Cats
and rats are remarkably fond of it, and it is employed
by rat-catchers as a decoy. This oil is convertible
into cclerz'c, or celerz'mzz'c acid, which has been detected
in a variety of products, and is one of the few organic
substances which can be produced artificially. This
acid forms, with bases, a class of anhydrous salts termed
valerales: they have a sweetish taste; some may be
obtained crystallized; others are amorphous.
VALONIA. See LEATHER, Section 11.
VALVE. See STEAM-ENGlNE—AIR-PUMP—PUMP,
&c.
VANADIUM, V.68, a rare metal, discovered by
Seftstrom in 1830 in one of the Swedish iron ores,
and named after Vanaclls, a Scandinavian deity. It
also occurs in the mineral canaclz'ale of lead. Vana-
dium is a white brittle substance, very infusible, not
oxidised by air or water, nor acted on by sulphuric,
hydrochloric, or hydrofluoric acid. It is dissolved by
aqua regia, and forms a solution of a deep blue colour.
There is a prolcs'z'cle, VO, a bivzcrcz'de, V02, which
forms with acids a series of blue salts, which tend to
become green, and then red, the production of
Vmzadz'e acid, V03. This acid unites with bases
forming a series of red or yellow salts.
VANILLA, the fruit of a genus of plants, the type
of the natural order Vanillacem, much used on the
continent of Europe for flavouring cakes, sweetmeats,
liqueurs, ices, chocolate, &c. When the Spaniards
discovered America, they found that the Indians were
accustomed to flavour their chocolate with this sub-
stance, the name of which is said to be derived from
caym'llc, a diminutive of rag/m, the Spanish for a knife
or scissor-case, the fruit being long and cylindrical
like the sheath of a knife. Vanilla has a balsamic
odour, and a warm, agreeable flavour, which properties
are due to a volatile oil and the presence of benzoic
acid. When the fresh fruit is opened it is found to
contain a black, oily, balsamic liquid, in which a large
number of granules are floating. The fruit is pre-
pared for the market by drying. The finest kinds of
vanilla of commerce are imported from Vera. Cruz, the
plant being cultivated about 241 leagues north-west
of this port at a place called Misantla in Venezuela.
The mode of cultivation is described in “Buchner’s
Repertorium ” (Band xlv.), from which we obtain the
following particulars :—Vanilla requires a damp but
warm climate, and a good soil. Hence a ground with
low shrubs which give little shade is best adapted.
The ground need not be tilled, but on the approach
of the rainy season, slips of vanilla are planted at the
root of a tree or shrub, and as the plants grow they
creep up around the trunk. Once a year the planta-
tion is cleared of the exuberant shrubs, and in the

third year the plants bear fruit. At Misantla five
sorts are distinguished :——1. La Ccrrz'erzle', of which
there are two kinds; one with a delicate fine skin,
rich in seeds and pulp, and the other of an inferior
quality, with a thick skin; the lee, ley, or leg, of some
parts of South America, and the genuine vanilla of
commerce. 2. La sg/lceslre’ Cz'mm'rone, or Simarezza,
wild vanilla; the fruit is smaller than No. 1 ; it grows
in the shade or among the shrubs, so that its fruit
is less developed than the cultivated vanilla, with
which it is identical. 3. Meslz'za .- the unripe fruit is
green with brown spots; it is more cylindrical than
the genuine, and easily dehiscing or bursting open
on becoming dry. a. La Puerea: fruit smaller than
the first, and in the unripe state dark green: when
drying it evolves an offensive smell, from which
it is also called lzcg vanilla (Vanilla cle coo/ion).
5. La Pompom. The fruit is shorter and thicker
than No.1, and has a very delicate epidermis. The
smell is pleasant, and is very evident when‘becoming
dry, but is not so agreeable as No.1: it loses its
smell in time, and hence is but little valued. It is
known in France under the name of V am'llon.
The harvest begins about December: the yellowish
green colour of the fruit, which was formerly green,
indicates its ripeness. The fruit, however, is some-
times gathered before it is ripe. The pedunculus is
always left on the fruit, and when, by drying, the
pedunculus has lost its green colour, the dressing
commences; for which purpose straw mats, covered
with woollen blankets, are spread on the ground, and
when heated by the sun the fruit is distributed over
them; and this, when warmed, is folded up in the
blankets, placed in boxes covered with cloths, and
further exposed to the sun. Within 12 hours the
fruit should have assumed a coffee-brown colour: if
not, the process is repeated next day. In unfavour-
able weather artificial heat is employed. The vanilla
is improved by daily exposure to the sun on mats for
about 2 months. The cultivator knows by experience
when the fruit is properly dry; if dried beyond a cer-
tain point, there is loss both in weight and quality.
When the dressing is complete the fruit is tied up in
bundles of 50 pods each, and packed in tin boxes.
Inferior sorts, such as Nos. 4! and 5, are sometimes
placed in the middle instead of the genuine sorts, of
which 5 kinds are distinguished; viz. primz'em, which
must be 24 centimes long, and proportionally thick,
and filled with pulp to the pedunculus ; cfiz'cc firm,
which is shorter than the foregoing, so that 2 fruits
are counted for 1; sacate, which is less thick than
the first, and at the base not quite filled with pulp;
resaccle, which is small and dry, 4: being reckoned for
1 : (these fruits were gathered before they were ripe) ;
and became, the most inferior sort, the fruit of which
is very small, spotted, and cut or broken. According
to another authority, the fruit is first allowed to fer-
ment for 2 or 3 days, then exposed to the sun, and
when about half dry, rubbed over with the oil of
palma Christi or the oil of cocoa. It is again exposed
to the sun, and oiled a second time.
The fragrant vanilla, V. plangfolz'a, was introduced
892
VANILLA—VARNISH.
by the Duke of Marlborough into Great Britain in
1800, whence it found its way to the gardens of the
Continent, and from Holland it was sent to Japan,
where it is now much cultivated: but as this plant
rarely flowered, and never produced fruit in Europe,
it was not supposed that it was capable of yielding
the vanilla of commerce. Professor Morren of Brus-
sels, however, has shown,1 that it is possible to pro-
duce in hot-houses in Europe vanilla equal or superior
in quality to that from Mexico. The species culti-
vated by him was also V. plamfolia, and he has shown
that it seldom flowers in Europe on account of its
not being allowed _to grow in lofty humid hot-houses.
The plants should not be under 5 or 6 years of age:
they should be shaded, and supplied with heat and
moisture. The best soil is coke placed over small
pieces of birch or poplar wood. The plants should be
allowed to creep up an iron frame or other support:
the branches should be twined, and their extremities
cut and burned with a hot iron to stop the flow of the
sap and stimulate the flowers. Under these favourable
circumstances, the plant flowers in Liege from Fe—
bruary to April, and when it bears fruit it requires a
year and a day to ripen. If the plants do not bear
fruit they flower again the next year, but if they bear
fruit they require some years’ rest before they blossom
again. There is a curious reason why the vanilla does
not produce fruit in Europe when it has flowered,
arising from the structure of the flower itself, “which
has this peculiarity, that the retinaculum is highly
developed, so that this organ forms a curtain sus-
pended before and above the stigmatic surface, thus
separating it completely from the anther, which in its
turn incloses in two cavities, naturally short, the pul-
verulent masses of pollen. From this structure it
'results that all approximation of the sexes in orchi—
deous plants is naturally impossible. It is thus neces-
sary either to raise the velamen or to cut it, when the
plant is to be fecundated, and to place in direct con-
tact the pollen and the stigmatic surface. The fecun-
dation never fails, and we may be convinced of its
success by observing the flower some hours after the
operation. If impregnation has been effected, the
sepals and petals reverse inwardly, and the flower
droops instead of remaining erect. So soon as the
following day the ovarium elongates.” The process,
which is thus required to be performed artificially in
Europe, is done naturally, by means of insects, in
countries where the plants grow.
Vanilla acts as a slight stimulant, and it is a
valuable addition to several articles of food in cases
where there is want of energy and activity in the
system. i
VAPOUR. See STEAM—EBULLITION.
VARNISH. A varnish is a solution of a resin or
of a gum-resin in a liquid, which, being spread over a
surface, evaporates, and leaves the solid in the form
of brilliant, transparent film. The principal sub-
stances used in varnishes are the following :—-
SoLvnN'rs. SOLID.S. COLOURS.
Oil of Nuts. Amber. E1 emi Gamboge. Annotto.
,, Linseed. Anime. ‘ Dragon’s Red Saun-
,, Turpentine. Copal. Benzoin. blood. ders.
,, Rosemary. Lac. Colophony. Aloes. Cochineal.
Alcohol. Ether. Sandarach. Arcanson. Saffron. Indigo.
Wood nap'hthal Mastic. Turmeric.
or pyroligne- Damar.
ous ether. ' J Common resin.


The resins, or as the varnish—maker calls them,
gums, may be used either singly or combined, and the
same remark applies to the solvents. One of the most
desirable qualities in a varnish is durability, a quality
which depends greatly on the comparative insolubility
of the resin employed, its hardness, toughness, and
permanence of colour. Amfler is most distinguished
in these respects: it resists the action of ordinary
solvents, and requires to be fused at a high tempera-
ture, for making varnish: it is hard, and moderately
tough, and its colour is scarcely acted on by the air.
The objections to amber are its costliness and the
length of time required for amber-varnish to dry: it
does not become full hard under many weeks. [See
AMBER] Am'mé is imported from the East Indies in
chests weighing from 3 to 5 cwt. Those which con-
tain the palest and largest gum fetch the highest
price. It should be scraped by hand before being
sold, but a good deal of it is pic/sled, that is, cleaned
from its rust-like colour, by being steeped for several
days in a strong alkali, well washed with a broom
and then rinsed with water. This kind sells for about
one-third less than that which has been scraped with
a knife. The varnish=maker picks out the large, pale,
transparent pieces, or they are sold separately as body-
gum; the next best in quality is separated from the
third and worst quality, which is used for gold-size or
japan'black. Anime is almost as insoluble and hard
as amber, but not so tough: the varnish made with it
dries quickly, but is liable to crack, and the colour
deepens by exposure to air and light. Anime is
largely used in oil varnishes, and there is a large pro-
portion of it in 002ml camislzes on account of its dry-
ing quickly. 001ml is produced in India, America,
the West Indies, Sierra Leone, 850. Dr. Lindley
says that “the copal of Madagascar, and probably of
the East Indies generally, is furnished by Hymeawa
eerracosa,” that “ Vaz‘erz'a India“ furnishes the resin
called in India equal, (in England known by the name
of gum mama) and very nearly approaching the true
resin of that name : in its recent and fluid state it is
used as a varnish, (called Pizzey varrn'sh,) in the south
of India, and, dissolved by heat, in closed vessels, is
employed for the same purpose in other parts of India;
it is extremely tenacious and solid, but melts at a
temperature of 97-;—o Fahr. Dr. Wight tells us that
the natives obtain it by the simple process of cutting
a notch in a tree, sloping inwards and downwards : the
resin collects there, and soon hardensf’z Copal is

(1) Professor Morren’s interesting paper was read before the
British Association at Newcastle, and inserted the third
'volume of the “ Annals of Natural History,” 1839.

(2) “ The Vegetable Kingdom,” 1846. On the Malabar coast,
this resin, under the name 0t‘ Piracy vDmnmar, is made into candles,
“ which difi‘use in burning an agreeable fragrance, give a clear
I
TVARNISHT
8w
, has a large collection of recipes for spirit varnishes.
‘generally imported in lumps about the size of small
potatoes, of a slightly yellow tint, and often including
insects and animal remains. It is often covered with
a clay-like substance, from which it is freed by the
dealers by_scrapi1ig. The finest and palest lumps
are selected for what is called hotly-gum ; the next
best form carriage-gum; and the ‘remainder being freed
from wood and stones, forms what is called t/zz'rcl, or
worst‘ quality, and is used for gold-size or japan-black.
Copal has a conchoidal fracture; it is transparent,
inodorous, and tasteless. Its density varies from
T0415 to 1'139. It softens by heat without becoming
viscid, and at a higher temperature fuses, partly de-
composes, and gives olf 'ari aroniatic odour. Copal is
next in durability to amber: the pale specimens,
when made into varnish, become lighter by exposure.
It is an excellent material ftii‘ varnishes, and attempts
have been made to use it as the basis of a spirit var-
nish; it is, however, so little soluble in alcohol, that
when boiled therein, only a small portion dissolves,
and the remainder swells and softens. It is said,
however, that by reducing eopal to an impalpable pow-
der, and exposing it for about 12 months to the action
of the air, it becomes soluble in alcohol, and may be
used for preparing varnishes. The addition of a small
quantity of camphdi' incredses the solubility of eopal
in alcohol; the sanhe ‘effect is prodiiced by fusing it,
setting it on fire, and allowitifgi it tii liiirn a few
minutes: these, and similar plziiid, ‘attests, produce
a very inferior varnis i. Oil d'f is said to be
one of the best solvents of eopal: ether is probably
the best solvent, but it evaporates so rapidly that the
varnish cannot be spread equally. The oils of spruce
and lavender have alsd been iised as solvents.
The three resins, saber, animc, and eopal, either
separately or mixed in certain proportions, are con-
verted into varnish by fusion and the addition of
linseed-oil heated nearly to its boiling point: the
combination of the resin and the oil is promoted by
stirring and boiling; and the required degree of
fluidity in the varnish is attained by the addition of
oil of turpentine. These are the most important of
the oil mama's/les } they are the inost durable, they
are hard enough to bear polishing, ‘and they possess
considerable brilliancy. They are used for works of the’
best quality, such as are exposed to the weather or to
much friction, as coaches, japan-work, and house
decorations. _ -
Lac and madame/1. form the basis of spirit car-
m's/ics: these resins are niore soluble than amber,
anime, and eopal; they are dissolved in spirit of
wine, or pyroligneous spirit, which is cheaper. In
France, where alcohol is very cheap and abundant,
spirit varnishes are largely employed.1 They are use
for cabinet and painted works not exposed to the
weather. [See Lnc—Sannnnacn] Lac is harder

bright light with little smoke, and consume the wick so as not to
require snufiing. Some of these candles that were sent home
were highly prized and sold for verf high prices.” (Wight) Their
importation was stopped by the high duties that were levied on
them.
(1) Dumas, in the seventh volume of his “ Traité de Chimie,”

than sandarach, and is the basis of most lackers [see
Lacuna], and also of French polish [see Fnnncn
Ponrsn]. Sandarach is used for making a pale var-
nish for light-coloured woods": it may be hardened by
the addition of shell-lac or of mastic if requiredhto ‘be
kept pale ; and when required to be polished, Venice
turpentine is added to give it body. '
Mastic is a soft resin: dissolved in spirits of wine
or oil of turpentine it makes a very pale varnish: it
is brilliant, works easily, and flows better on the sur-
face than most other varnishes. It can also be re-
moved by friction with the hand, hence its use
as a picture varnish and for other delicate works.
See MAsTIc. ‘ ;
Damar is softer than mastic: it forms an almost
colourless varnish with turpentine: mixed with mastic
it forms a moderately hard, flexible, and almost
colourless varnish adapted for maps and similar pur-
poses. " ‘
Common resin, dissolved with the assistance of heat
in turpentine or linseed oil, makes a hard, brittle,
brilliant varnish, which is employed for common pun
poses, as in house painting, toys, cabinet work, &c,
It improves the brilliancy of other varnishes, but
renders them brittle unless used sparingly.
The linseed oil, used as tlievehicle for the harder resins,
should be pure,)pale, well clarified, and combined with
the resin at as low a temperature as possible. Unless
these conditions be attended to, a dark varnish is pro-
duced which becomes darker by age. This oil gives
softness ‘and tohghness to the resin, but procliiceis a
slowly drying varnish. It is clarified for the best
varnishes by being gradually raised to neai‘ the bpiling
point in a copper pan, Fig. 2221. About 2 hours
should be occupied in attaining this tempeiatiire: it
is then skimmed ._..__’ and left to sim~ 'Mfl— '’
iner for about
3 houijs longer.
About ri- oz. of dry
magnesia per gal—
lon of oil is then
gradually stirred
in‘: the heat is kept up for another‘hour, and the
whole is then left to ‘cool very slowly. After this
it is transferred to lead or tin cisterns, and left
tranquil for about 3 months, when the magnesia
combines with the impurities of the oil and sub-
sides. The clarified oil is drawn off from above,
and the lower portion‘ is used for black paint.
A pale drying oil may be prepared in this way by
substituting for magnesia, 2 oz. of white ,eopperas
(sulphate oflzinc), and 202.. of sugar of lead, to every
gallon of oil.‘ Linseed oil, converted into a drying
bil by boiling and adding litharge and fed-lead, is
sometimes used as a cheap varnish. The linseed-oil
is raised to the boiling point in about 2 hours, and
after skimming, about 3 oz. each of lithar'ge and
red—lead per gallon of oil are slowly sprinkled in, and
the whole is boiled for about 3 hours, or until little
scum is formed or much smoke emitted. The varnish-
Fig. 2221.
maker judges whether the oil be properly boiled by
8941
VABNISH.
dipping the end of a feather into it; if it be burnt off,
or curl up briskly, the boiling is sufficient. The oil
is then left to cool very gradually, during which the
larger portion of the driers subside. The oil is pre-
served in close leaden cisterns. For a pale oil the
driers are white lead, sugar of lead, and white
copperas.
Turpentine is in extensive use for varnishes, either as
a vehicle for the resins or for thinning oil varnishes,
in which case it is used hot. The turpentine should
be of the best quality, clean and limpid; it is greatly
improved by age, and should be kept for months or
even years. Turpentine varnishes are cheap and
flexible; they dry more quickly than oil varnishes,
and are of a lighter colour, but not so tough or
durable. Mastic, damar, and common resin may be
dissolved in oil of turpentine either cold or at a
gentle heat.
Also/lot or spirits of wine is used as the vehicle for
sandarach and shell-lac, as in the white and brown karat
spirit narnz'sfies. Spirit varnishes dry more quickly,
harder and more brilliant than those made with tur-
pentine. The spirit must contain very little water
or it will not dissolve the resins ; and in applying the
varnishes a moderately moist atmosphere is sufficient
to occasion such a precipitation of the resins as
to produce a dull, cloudy, or milky effect on the
varnished surface: in which case the varnish is said
to be ckz'tted. The varnish-maker ascertains whether
the spirit is strong enough by steeping a piece of
writing paper in it and setting it on fire ; if the flame
consume the paper the spirit is judged to be suf-
fieiently strong; if not, it contains too much water.
See ALCOHOL.
Napkt/za or pyroligneous ether is objectionable on
account of its smell, but is used for cheap varnishes.
It dissolves the resins more readily than ordinary
spirit of wine, but the varnish is not so brilliant.
The other substances mentioned in the table at the
head of this article do not require further notice in
this place. Most of them are described under their
respective heads. The colours are chiefly used for
lackers. See Laonnns.
Considerable heat being required in the preparation
of oil varnishes, and the materials employed being very
inflammable, the factory should be detached from
other buildings and constructed for the purpose.
Directions respecting the structure of the buildings,
the utensils, &c. required, and the processes adopted
in the manufacture of varnishes, are given by Mr. J.
Wilson Neil in his Essay contained in the 49th vol.
of the “ Transactions of the Society of Arts.” Mr.
Neil was presented with the Society’s Gold Isis Medal
for this Essay, to which we have been considerably
indebted in the preparation of this article.
The copper used for the purposes of boiling oil,
gold-size, Japan, and Brunswick black, &c., is called
a set-pot, and is represented in Fig. 2222, with the
flue winding round it. The gum-pot, in which the
resins are fused, is set in a small furnace as shown in
Fig. 2223. The gum-pot is of copper 2 feet 9 inches
high and 9% inches diameter. The lower part a is

raised out of one piece; the upper part b is of sheet
copper, cylindrical, 10 inches diameter at the top and
2 feet 2 inches high, and is attached by rivets to the


w!
’
__ ,p ’
_____—-.---— ,/
___ __ _,-¢-—
M -- I__
--_
s ,r
_ \
~ \ 1'
~_ _-~. -
~_ -~-_ ---- -w. “'-
~-___,___-_---’




My
Fig. 2222. 'run snr-ro'r.


\\\\\/
Q’ A
'
rz/nnr a ' -________ \
Ra ~'


Fig. 2224.
1301 LIN G-POT-
lower part or bottom
a ; but before rivet-
ing, a flange of copper
is fixed just below the
large rivets; an iron
hoop (Z, with an iron
handle, is also at-
tached to the cylinder.
A copper boiling—pot,
shown in elevation
and plan, Figs. 2224,
2225, is required; the
bottom, shown by the dotted lines, is raised out of
the solid, and is 7 inches high and 20 inches in out-
side diameter: the eylinder' or body of the pot is

“.1
Fig. 2225. Plan.
_ VARNISH. ~ * e
*895
2 feet 10 inches high, and’ is well riveted to the
bottom, the rivets being hammered inside and out
“W so as to project and sup-
port the pot and its con—
tents instead of a flange.
The pot is made to fit neatly
into a hole in a plate of iron,
Fig. 2226, which covers the
53% top course of the brick-
“ ' work. The cylinder has a
Fig. 2226. strong handle on each side.
The utensils required are ladles, stirrers, (of the
form shown in Fig. 2227,) and funnels of copper;
i‘ an oil-jack, Fig. 2228,
a?‘ ) of the capacity of 2
Fig- 2227- gallons, for pouring in
hot or boiling oil; a brass or copper sieve, 60 meshes
to the inch and 9 inches diameter, for straining the
varnish; a brass sieve, 40 meshes to
the inch, 9 inches diameter, for strain-
ing gold-size, turpentine, varnish,
boiled oil, &c., and a similar sieve for
straining japan and Brunswick black :

5a
Fig‘ 2228' a saddle, Fig. 2229, or sheet of tinned
% iron 12 inches broad and turned up
1;‘; inch; it is placed between the
Fig. 2229.
edges of the set-pot and the funnel to
receive the drops of varnish spilled during the taking
out. A pot like a watering—pot without a rose is
used for pouring oil of turpentine, and there are a
few other articles which do not require particular
notice.
For making varnish on a small scale a gum-pot
similar to that shown in Fig. 2223, or smaller, may be
used; also an iron tripod with a circular top into
which the gum-pot will easily fit. The operation may
be conducted in a hollow in a field, yard, or out-house,
and a temporary fire-place be raised round the tripod
with loose bricks similar to a plumber’s furnace: the
fuel to be preferred is coke or charcoal. When the
fire burns with a strong heat, set on the gum-pot with
3 lbs. of copal in it. The fire should not rise higher
outside the pot than the depth of melted copal, or the
resin is likely to catch fire. As soon as the copal
begins to fuse it should be constantly moved about and
divided with the copper stirrer; if it feels lumpy and
rises to the middle of the pot, it must be lifted off the
fire, placed upon a bed of ashes1 by the side, and kept
stirring until the swelling subsides. The gum-pot- is
again put on the fire and stirred until the resin has
become as fluid as oil, which is ascertained by lifting
up the stirrer so far as to see the blade. Then call
out to an assistant, “ Be ready!” and he then lifts up
the jack, Fig. 2228, full of clarified oil, and rests the
spout on the edge of the gum-pot. When the gum
rises to within 5 inches of the pot~moutb, call out
“ Pour !” when the oil is to be poured in very
slowly, the maker continuing the stirring. In 8 or 10
(1) The ash-bed is formed by sifting dry ashes through afine
sieve; it is to be made a little larger than the bottom of the pot,
15; inch deep and smooth and level on the surface. Instead of the
ash-bed a circle of loose bricks 4 courses high may be erected to
support the gum-pot.


minutes with a strong fire the oil and the resin will
have combined into a clear varnish; this is to be
ascertained by lifting up the stirrer and dropping a
little of the varnish from it upon a piece of broken
glass; if it ‘be clear and transparent the combination
has been effected; but the varnish must be boiled
until a drop pinched between the finger and thumb
will on separating them draw out into fine filaments;
if not boiled enough the varnish will be soft, thick
and greasy. The string—test must be tried every
minute or less, and the moment it is satisfactory the
pot is removed to the ash-bed and left for 15 or 20
minutes. When cold enough for mixing, oil of tur~
pentine is poured out from the pouring pot in a small
but gradually increasing stream; if the varnish rise
rapidly in the pot, it must be constantly stirred at
the surface to break the bubbles; but the stirrer must
not be allowed to touch the bottom of the pot, or the
turpentine will be partly converted into vapour and
cause the varnish to overflow. If, however, the
varnish should rise so as to become unmanageable
with the stirrer, the temperature may be lowered by
means of the copper ladle, a ladleful being taken out
and poured back again many times. When the
mixing is complete the varnish sieve is put into the
copper funnel, and this into the carrying tin, and the
varnish is strained; it is emptied into jars or cisterns
and left for a time, the longer the better, to settle.
When taken out for use the bottoms must not be
' disturbed.
In making varnishes on a larger scale, the boiling—
pot and the gum-pot will probably have to be used at
the same time. Set on the boiling-pot with 8 gallons
of oil, and kindle the fire previously laid; then lay
the fire in the gum furnace, and have as many 81b.-
bags of gum weighed out as will be required: put one
Slbs. into the pot, and kindle the fire. In about 3
minutes, with a brisk fire, the gum will begin to fuse
and smoke: stir, and divide it, and attend to the
rising as before. In about 20 minutes the 8 lbs. of
copal will be fused into a clear liquid. By this time
the oil should be brought to a simmering state as if
beginning to boil; when this is the case, the maker
calls out, “Bear a hand!” and the maker and his
assistant lift the boiling pot by its handles out upon
the ash-bed. The maker instantly returns to the
gum-pot, while the assistant puts 3 copper ladlefuls
of oil into the pouring jack, which he places on the
iron plate at the back of the gum-pot to keep hot until
wanted. When the gum is nearly fused the maker
calls out, “Ready oil!” when the assistant lifts up the
jack to the edge of the pot, and when the maker calls
out, “Oil!” he pours it in, the boiling being conti-
nued until the mixture has become clear. The gum—
pot is now set upon the stand until the assistant puts
3 more ladlefuls into the pouring—jack and 3 more into
a spare tin for the third run of gum. The boiling
pot will still contain 3% gallons of oil. The gum-pot
is now raised by its handle, and the edge put over the
edge of the boiling pot, and its contents poured in.
When the maker is ready for this pouring, the assist-
ant stands by with a thick piece of wet carpet without
996
VARNISH.
holes, large enough to cover the mouth of the boiling
pot should it catch fire during the pouring, which
sometimes happens when the gum-pot is very hot.
Should the gum—pot fire it has only to be kept in-
verted and it will go out of itself; but if the boiling
pot fire during the pouring, the assistant throws the
piece of carpet over the blazing pot, holding it down
all round the edges, and in a few minutes it will be
smothered. The moment the gum-pot is‘ emptied,
half a gallon of turpentine is poured into it, and it is
washed with the assistance of a broom, called a 82021972,
and then emptied into a flat tin-jack: the pot is
wiped dry, another Slbs. of gum put into it, and it is
set on the furnace. This and the third run are treated
like the first; when the boiling-pot will contain 8
gallons of oil and .‘Zllilbs. of gum, a strong fire is to be
kept up until a frdth or scum rises and covers the
surface. When it rises up to the rivets of the
handles, the boiling-pot is removed from the fire to
the ash-bed, 'and the froth stirred down. This being
done, the pot is again put on the fire, and the re-
maiiider of the driers gradually introduced, always
removing the pot when the froth rises to near the
rivets of the handles. In about 3%; or A hours from
the pouring in of the last gum, the boiling may be
completed, but the time will vary with the weather,
the quality of the oil; of the gum, the driers, and the
state of the fii'e. About the third hour of boiling the
s'triiig test is applied: when this is satisfactory, the
pot is removed to the ash~bed and the varnish stirred
down until 'cold enough for the mixing. Five tins or
I5 gallons of turperitine are gradually poured in,
whidh will leave the varnish thick enough if the resin
is of good quality and has been well rung if not of
good quality; and not well fused, 12 gallons of tur-
pentine niay be too inuch. Therefore, after the
introduction of the latter quantity, a portion of the
varnish should be cooled in a saucer. It will be seen
in a few minutes whether it will take more turpen-
tine. The varnish is lastly strained and stored away.
The boiling-pot, ladles, stirrers, and funnel, must be
cleaned with the turpentine used in washing the gum-
pot. This turpentine is first poured into the boiling
pot, and the swish is used to wash the varnish from
the sides. A large piece of woollen rag is next to be
dipped into pumice powder, and every part of the in-
terior of the‘, boiling-pot washed and polished there-
with. The ladle and stirrers, &c. are similarly operated
6n, and rinsed in turpentine washings, and lastly in
"clean turpentine, and then wiped dry with a clean soft
Tag. The "sie’ve is to be kept in turpentine, which will
prevent it from gumming up.
The above directions mostly apply to the inaking of
an seas of copal varnishes. The proportions of oil,
‘gu‘iii, &'c.; ali'e subject to variation, so that a few
retiipe‘s for compounding particular varnishes may be
bf use.
‘ _ CojJZzZ tamer for firzé paintings, §’6.—-F11S6 Slbs.
bf the cleanest pale African gum—copal, and when
‘completely fun fluid, pour in 2 gallons of hot oil: let
it boil until it striiigs ‘strongly ; and in about 15
ihinutés; while still very hot, pour in 3 gallons of tar.

pentine obtained from the top of the cistern. There
may be much less of turpentine during the mixing,
but the varnish will be so much the brighter, trans—
parent, and fluid, and will work freer, dry quickly,
and be very solid and durable when dry. If the var»
nish' be too thick after being strained, hot turpentine
is to be added before the varnish is quite cold.
Artist’s virgin 001ml. -——From a select parcel of scraped
African gum-copal, before it is broken, pick out the
very fine transparent pieces, which appear round and
pale like drops of crystal; break these very small;
dry them in the sun, or by a very gentle fire. When
cool, bruise, or pound them into a coarse powder.
Next, boil some broken bottles or flint glass in soft
water and soda, and pound the glass into a coarse
powder; boil it again, strain off the water, and wash
it in 3 or 41 waters, that it may be perfectly free from
grease, dry it before the fire, or in an oven. Mix
2 lbs. of powdered glass with 3 lbs. of powdered eopal;
put them into the gum-pot and fuse the gum, stirring
all the time: the glass will prevent the ‘gum from
adhering together, so that a very moderate fire is suf-
ficient to fuse the gum. When the gum is sufficiently
run, pour in 3 quarts, of very hot clarified oil. Let
the varnish boil until it strings freely between the
fingers. Mix it rather hotter than if it were body-
varnish, for, as there is but a small quantity, it will
be sooner cold. Pour in 5 quarts of old turpentine,
strain it immediately, and pour it into an open jar or
large glass bottle; expose it to the air and light, but
keep it from the sun and moisture until it is of suffi-
cient age for use.
Cabinet varnish—Fuse 7 lbs. of very fine African
gum~copal, and, when well run, pour in half a gallon
of pale, clarified oil: when clear, mix it with 3 gallons
of turpentine, and strain. This, if properly boiled,
will dry in 10 minutes; but if boiled too strongly it
will not mix with the turpentine; and sometimes,
when boiled with the turpentine, it will mix, but will
not combine with any other varnish that has been less
boiled than itself. This varnish is used by japanncrs,
cabinet, and coach painters. Anime is however gene-
rally, used for cabinet varnish.
Best cod] col/val varnis/t,_ for the body parts of
coaches and other objects intended for polishing, is
made by fusing Slbs. of fine African gum-copal, and
adding 2 gallons of clarified oil. It must be boiled
very slowly for A or 5 hours until quite stringy, and
be mixed off with 3% gallons of turpentine.
The foregoing varnishes are made of the finest
copal without the addition of driers; they are the
palest and best of their kind, and have great fluidity
and pliability. They are, however, slow in drying, and
it requires months for them to become hard enough
to polish well. If the varnish is not required to be
very pale, gum of second quality is used, and if re-
quired to dry quickly, sugar of lead or white copperas,
singly or together, are used in the proportion of 2; lb.
to I lb. to each of the quantities given in the recipes‘;
but the brilliancy, colour, and durability of varnishes
are injured by the introduction of driers. If the var~
nish be required to dry and harden quickly withoi'it
WKRNISHT
897
the use of driers, anime may be used instead of eopal,
but it does not form so durable a varnish, and it be-
comes darker by age. Anime varnish may be mixed
with eopal varnish in certain proportions, while both
are hot. A moderately quick drying body-varnish
may be made by mixing 1 part of anime with 2 parts
of eopal; for an inferior varnish, drying more quickly,
2 parts of anime to l part of eopal may be mixed.
C’arriage varnish tor the wheels and under frame-
work of coaches and other objects not requiring to be
polished is made like common body-varnish, only that
to Slbs. of gum of second quality are used about
2%,— gallons of oil and 5% gallons of turpentine, with
driers. This varnish is boiled until it becomes very
stringy. Its quality is intermediate between body-
Varnish and
Wainscot varnish, which is made of 8 lbs. of anime of
second quality, 3 gals. of clarified oil, % lb. of litharge,
% lb. of sugar of lead, :1 lb. of copperas. These ingre-
dients must be well boiled until the varnish strings
very strong, and it must be mixed with 5!; gals. of tur-
pentine. This varnish, which dries quickly, is used
chiefly for house painting and japanning. It may be
darkened by the addition of a small quantity of gold
size.
Spirit and turpentine varnishes are prepared by mix-
ing the resins and the solvent together, and agitating
the whole with a stick with a number of pegs or nails
driven in near the lower end until the solution is
complete. The resins should be dry, and in small
pieces, with the impurities picked out : the finest and
clearest pieces of the gum are set aside for superior
varnishes. Turpentine varnishes are made in quanti-
ties of 10 or 12 gallons : spirit varnishes from 41 to 8
gallons. In making the latter, the ingredients are
sometimes put into a cask of 8 or 16 gallons’ capacity,
and mounted so as to revolve upon bearings at the
ends. An alternating motion is given to the barrel
by passing round it a cord terminating in a cross
handle. When the operator pulls this cord towards
him the barrel rotates, and winds the cord up in the
other direction so as to be ready for a second pull,
which, in like manner, winds the cord in the opposite
direction, and so on. Agitation must be kept up, or
the resin will agglutinate. After 3' or 41 hours, or
when the solution is complete, the varnish is left for
a few hours to deposit solid impurities, and is then
strained through muslin or lawn into bottles. Coarsely
pounded glass is sometimes added to prevent the
agglutination of the resin. When heat is employed
in making spirit-varnishes, the source of heat should
be a water or a sand bath, and a still and worm may be
used to prevent loss by evaporation, the resins and
solvent in the still being kept in motion by a stirrer
passing through a stuifing-box in the head. Shell-lac
contains a little wax, which is apt to get diffused
through the varnish when heat is applied. The in-
flammable nature of the ingredients will of course
suggest the necessity for caution in making spirit-
varnishes. The utensils employed must be quite clean
and dry.
Best white hard .spiritwmwish, such as will bear
VOL. II.

polishing, is made by adding 2 lbs. of the best picked
gum-sandarach to 1 gallon of spirits of wine, and
agitating for 4 hours, until the solution is complete.
18 ozs. of Venice-turpentine, (or 9 ozs. if the work is
not to be polished,) are to be moderately heated in a
water-bath until quite fluid, and added to the varnish
to give it body. Agitate for an hour, strain and put
into bottles, which must be kept well corked. Al'ter
remaining undisturbed for a week, the varnish is fit for
use. If the clearest and palest pieces of gum be se-
lected, this varnish will be pale enough for white work.
White hard varnish—(No. l.) 3%; lbs. of gum-sand-
arach to 1 gallon of spirits of wine, and when the
solution is complete add 1 pint of pale turpentine-
varnish, and shake the whole well together. (N o. 2.)
2lbs. of gum-sandarach, 11b. of gum-mastic, and 1
gallon of spirits of wine. White spirit-varnish for
victim—2 lbs. of mastic to 1 gallon of spirits of wine
and 1 pint of turpentine-varnish.
Brown hard spirit-varnish is similar to white hard
varnish, only shell-lac is used instead of sandarach.
Dissolve 2lbs. of shell-lac in 1 gallon of spirits of
wine, and then add 18 ozs. of Venice-turpentine,
warmed. This varnish will bear polishing. Or, 2 lbs.
of shell-lac, llb. of sandarach, and 202s. of mastic
dissolved in 1 gallon of spirits of wine. A lighter
colour is produced with 2lbs. of sandarach, 11b. of
shell-lac, and 1 gallon of spirit. When the solution
is complete add a pint of turpentine-varnish, and agi-
tate the whole well together. If a pale lac-varnish be
required, white or bleached Z£t0 may be used. Lac-
varnish may be bleached by Mr. Leming’s process :—
“ Dissolve 5 ozs. of shell-lac in a quart of rectified
spirits of wine; boil for a few minutes with 10 ozs. of
well-burnt and recently heated animal charcoal, when
a small quantity of the solution should be drawn oft‘
and filtered; if not colourless, a little more charcoal
must be added. When all colour is removed, press
the liquor through silk, as linen absorbs more varnish,
and afterwards filter it through fine blotting-paper.” 1
When eopal is added to spirit-varnishes in order to
increase their toughness and durability (although the
advantage of adding eopal may be questioned), the
eopal should be in fine powder, the spirit very strong,
and a gentle heat of about 120°, with frequent agi-
tation, should be used. A light-coloured varnish
may be made with glb. of shell-lac, g lb. of eopal, to
1 gallon of strong spirit.

(1) Transactions of the Society of Arts, vol. xlv. In the same
volume is a recipe by Mr. G. Field for bleaching lac-varnish by
means of chlorine. Dr. Hare has also published a method as
follows :-—-“ Dissolve in an iron kettle 1 part of pearlash in about
8 parts of water, add one part of shell or seed-lac, and heat the
whole to ebullition. When the lac is dissolved cool the solution and
impregnate it with chlorine gas till the lac is all precipitated.
The precipitate is white, but the colour deepens by washing and
consolidation; dissolved in alcohol, lac bleached by this process
yieldsavarnish which is as free from colour as any eopal varnish.”
The application of the chlorine must be made by a person ac-
quainted with chemistry. Hence chloride of lime is safer as a
bleaching agent, the lime being afterwards dissolved out from the
precipitate by the addition of muriatic acid. The precipitate is to
be washed several times, dried and dissolved in alcohol with the
addition of a little mastic. This varnish is very pale, but rather
5 thin.
3M
898
VARNISH.
Mastic varnish for paintings is generally made by
adding 3lbs. of mastic to 1 gallon of turpentine. The
mastic should be carefully picked and dissolved with—
out heat. After straining, the varnish should be kept
in a bottle, loosely corked, and exposed to the sun
and air for a few weeks. A deposit takes place, and
the clear varnish may be poured off, but it improves
by age. Mastic varnish is liable to chill from the
presence of moisture; but this may be carried down
by adding ,1. pint of well-washed hot sand to each
gallon of varnish, agitating for 5 minutes, and allow-
ing to settle.
Turpentine earnish.——Dissolve a lbs. of common resin
in 1 gallon of oil of turpentine at a gentle heat in the
sand—bath. The usual plan, however, is to dissolve
the resin in the gum —pot. For a pale varnish, bleached
resin may be used at a very moderate heat. Turpen-
tine-varnish is used for indoor painted works, and
common painted furniture and toys. It also adds to
the body, hardness and lustre of other varnishes.
Cry/stat varnish for maps, prints, coloured drawings,
&c.—Dissolve 2lbs. of mastic, 2lbs. of damar, with-
out heat, in one gallon of turpentine; or mix Canada
balsam and oil of turpentine in equal parts. Warm
the balsam until quite fluid and add the turpentine,
agitating for a few minutes; then leave the varnish
in a moderately warm place for a few hours, and it
will be ready for use the next day. A coat of thin
crystal varnish applied to one or both sides of good
tissue or foreign post paper, furnishes tracing paper
of medium quality.
Paper varnish for paper hangings, &c.-41 lbs. of
damar to 1 gallon of turpentine. White or bleached
resin may also be used, alone, or mixed with the
damar,
Water varnish—Lac is soluble in a hot alkaline
solution, and furnishes a varnish that will bear wash-
ing. The alkali deepens the colour of the varnish,
but ammonia does so less than borax, potash or soda.
1 Gozsof liquor ammoniae to 7 pints of water, with 2lbs.
of pale shell-lac and 4: ozs. of gum arabic, give a pale
water varnish. Borax is, however, commonly used in
the proportion of 2lbs. of shell-lac, 6 ozs. of borax,
a ozs. gum arabic, and 1 gallon of water. White lac is
used for the palest water varnishes.
lS’eaZing-waa' varnish for coating apparatus, &c.-—
Dissolve 2% lbs. of red sealing-wax and 1% lb. of
shell-lac in 1 gallon of spirits of wine.
Blae/s varnish—3 lbs. of black sealing-wax and 1 lb.
of shell-lac to 1 gallon of spirit: or mix fine lamp-
black with brown hard varnish or lacker. Such a
varnish is used for blackening the interior of telescope
tubes, the lamp'black serving to deaden the bright
colour of the lacker. A black varnish for metal works
may be made by fusing 3 lbs. of asphaltum, and % lb.
of shell-lac, and adding 1 gallon of turpentine.
Our space will not admit any more recipes for
varnishes, but we may conclude this part of our
subject with Mr. Neil’s general remarks on the making
of copal varnishes. He says,——“ The more minutely
the gum is run or fused, the greater the quantity and
the stronger the produce. The more regular and

longer the boiling of the oil and gum together is con-
tinued, the more fluid or free the varnish will extend
on whatever it is applied. When the mixture of oil
and gum is too suddenly brought to string by too
strong a heat, the varnish requires more than its just
proportion of turpentine to thin it, whereby its oily
and gummy quality is reduced, which renders it less
durable; neither will it flow so well in laying on.
The greater proportion of oil there is used in varnishes,
the less they are liable to crack, because the tougher
and softer they are. Increase the proportion of gum
in varnishes, the thicker the stratum, and the firmer
they will set solid and dry quick. When varnishes
are quite new made, and must be sent out for use
before they are of sufiicient age, they must always be
left thicker than if they were to be kept the proper
age.”
Varnishes are applied to flat surfaces with soft
clean brushes, and for spirit varnishes camel’s hair
pencils and brushes are used. The varnish should
be applied in very thin coats, sufficient time being
left between two coats for the solvent to evaporate.
Spirit varnishes require 2 or 3 hours between every
two coats, turpentine varnishes 6 or 8 hours, and oil,
varnishes 2a hours; but the state of the atmosphere
will require these intervals to be varied. The second
coat should never be added until the first is quite
hard. Care must be taken not to allow dust or loose
hairs from the brush to get attached to the varnish:
if hairs, &c. do get on, they must be carefully picked
out with the point of a knife before the varnish dries,
and the surface of the varnish be levelled with fine
glass-paper before the next coat is put on. A dry,
moderately warm atmosphere (such as that indicated
by a temperature of 7 2°) is required for varnishing,
and especially for spirit-varnishing, where the presence
of moisture causes a slight precipitation of the resin,
producing the effect that is called shitting as already
noticed; whereas if the air be kept quite dry during
the evaporation of the spirit, the resin is left on the
surface as a thin glassy coat, which is no longer
influenced by moisture, but acts as a perfect trans—
parent protection to the surface to which it has been
applied. Cold draughts will also produce the effect
of chilling. When the varnish has been chilled, it
may often be restored to its required lustre by apply-
ing a thin coat of varnish and placing the object at
such a distance from the fire as partially to dissolve
the chilled coat. Care must, however, be taken not
to raise blisters. The articles to be varnished should
be smoothed with fine glass-paper, and minute holes
in the wood should be stopped with gum or wax.
The varnish is usually contained in an ordinary pre-
serve jar, with a wire or string drawn across the top
for drawing the brush against so as to reduce the
quantity taken up. Enough varnish should be kept
in the jar to cover the hairs of the brush; should the
varnish become too thick by evaporation it may be
thinned down by the addition of spirits of wine, and
in general a better effect is produced by the applica-
tion of a number of thin coats than of a few thick
ones. Spirit varnishes should be put on rapidly, and
VAIRNISH—TVEN EER—VENEERIN G.
899
be well worked in so as to exclude minute air-bubbles.
Some skill is required td produce a uniform effect,
especially in large surfaces. The first coat of varnish
is generally absorbed more or less by wood and porous
surfaces, and the absorption raises the grain of the
wood, so that a second and even a third coat may be
required to fill up the pores uniformly. The work is
then smoothed with fine glass-paper, and 2 or 3 coats
of varnish are afterwards applied. As the absorption
of the first layers produces a great expenditure of
varnish, it is sometimes usual to substitute for the
first layers size made of pale glue or parchment
cuttings, or solutions of isiuglass or tragacanth.
Turpentine and oil varnishes are applied generally in
the same manner as spirit varnishes, but as they dry
more slowly it is easier to produce a uniform effect on
large surfaces with them than with spirit varnishes.
Coloured works receive their coat of colour before
being varnished.
The finestkinds of varnish-works, such as the wooded
work of harps, is thus performed:—:“ The wood is
covered with about 6 layers of the white hard varnish,
and allowed thoroughly to dry between each; this
entirely fills up the pores of the wood; the face is
then rubbed quite smooth with fine glass-paper. The
ornamental painting is then done, after which about
8 or 10 coats more of varnish are laid on, and at every
third coat the surface is rubbed with fine glass-paper
to remove the brush marks. When all the varnish
is put on and has become hard, the surface is rubbed
with fine pumice-stone powder and water on woollen
rags; the work is allowed to stand for a day or two,
and is then polished with yellow tripoli1 and water,
after which it is washed quite clean with a sponge
and wiped dry with a clean wash-leather. The varnish
is now touched at a few places with the finger smeared
with fine rendered tallow, which is then thoroughly
rubbed all over with the ends of the fingers; clean
wheat flour is dusted over the work, and also well
rubbed in with the fingers ; and after the removal of
the flour, the surface is slightly rubbed with a clean
old silk handkerchief, which completes the splendid
lustre given to these instruments.”
VAULT. See Bnrnen.
VEIN. See Minn-MINING.
VEINSTONE or GANGUE.
MINING.
VELLUM. See Panenunnr.
VELVET. See Wnavrne.
VENEER—VENEERING. The art of covering
a cheap and inferior wood with a thin layer of wood
of a more ornamental and costly character is not a
modern invention. The elder Pliny refers to it as a
recent invention in his time, suggested doubtless by
the large sums which the luxurious Romans were
accustomed to pay for solid tables of rare and costly
woods.3 Pliny speaks of the ingenious art of convert-
See MINE —-

(l) Tripoli and rottenstone for such works as these are prepared
for use by grinding very fine with a stone muller.
(2) Holtzapfi'el, Mechanical Manipulation, vol. There is a
long and instructive chapter in this volume on Var-nishing,
Lackering, J apanning, Bronzing, &c.

(3) The most costly wood in the time of Cicero, was pro- ,
ing the cheaper into the most valuable woods, by plat—
ing them with the latter, so that by cutting a tree into
thin slices, it may thus be sold several times over.
In the cutting of veneers, it is of course desirable
to economise the material as much as possible, and
hence it is now usual to employ very accurate ma-
chinery for the purpose. They were formerly cut at
the saw-pit, with very thin plates strained in the
common pit-saw frame [see SAW], or they were cut
with the smaller frame-saw, as is now done on the
Continent. Skilful pit-Sawyers would cut 6 veneers out
of every inch of wood, and cabinet-makers 7 or 8 from
smaller pieces, but as the veneers increased in size the
difliculties of cutting them accurately were greatly in-
creased. Small veneers for the backs of brushes, &0.
were split or planed from small pieces squared to the
required sizes. The scale-boards for making hat and
bonnet boxes are cut by a PLANING-MACHINE, as
noticed under that head. The method of producing
continuous shavings of this kind is important where
the material is costly, for the ordinary veneer-saw
cuts on the average one-third of the material into saw-
dust. It is said to have originated in Russia, and by
its means the veneers are cut spirally from a cylinder
of wood with a knife of the same length as the cy-
tlinder. Ivory has been cut in this way into sheets of
large dimensions. Pape, of Paris, some years ago,
veneered a piano-forte entirely with ivory, and adver-
tised to"supply sheets as large as 30 by 150 inches.
In the United States department of the Great Exhi—
bition was an ivory veneer 12 inches wide, and 40 feet
long, cut out of a single tusk. In 1806, Mr. Brunel
patented a method of splitting veneers of large size
by means of a horizontal knife composed of several
pieces of steel placed exactly in a line on their lower
surfaces, but with their edges slightly rounded and
very keen. A short reciprocating or sawing motion
was imparted to this compound knife, and the block
of wood to be cut up was carried slowly sideways be-
neath the knife by means of a screw-slide worked with
a spoke-wheel. When one veneer had been cut ofl’
and the log restored to its first position, it was raised
in exact parallelism by a system of two right-and-left-
handed screws at the four angles of the frame, and
which were all moved together by means of one winch-
handle. This machine answered the purpose when
veneers were to be cut from straight-grained and pliant -
woods, such as Honduras mahogany: but with woods
of irregular and brittle grain, such as rosewood, the
veneer curled up or split. The circular saw, although
so wasteful of the material, is therefore commonly
used for cutting veneers; and in order to give the

cured from a tree named citrus, a native of Mauritania, near
Mount Atlas. In leaf, trunk, and odour it resembles the female
wild cypress; the most valuable part is a. tuber or warty excre-
scenee, which when found on the root and underground is more
esteemed than when growing on the branches. When cut and
polished, it presents various figures, such as curling veins, or con-
centric eye-like spots; the former have procured for the wood the
name of tiger-wood, the latter panther-wood. A table of this
kind is said to have cost Cicero a million of sesterces, or £8,072
sterling. Even higher prices are quoted for the solid tables. See
Mr. Aikin’s paper on “ Ornamental Woods,” in the Transactions
of the Society of Arts, vol. 1.
03
M2
see
VENEER—VENEERING.
‘1
saw sufficient strength, it is made thick towards the
centre, and towards the edge it is thinned away
almost to a feather edge. The solid block of wood or
ivory is conducted along a parallel guide across the
flat face of the saw, while the thin pliant veneer
separates and forms an opening for the wedge-shaped
edge of the blade, the veneer passing uninterruptedly
along the conical back of the saw. For cutting large
veneers, the saw is composed of a number of seg-
ments or plates of steel screwed to the edge of a metal
disk, cast-iron wheel, or chuck, and is sometimes as
much as 18 feet in diameter. In all veneer saws the
edge must run very true, and the teeth must be sharp
and very faintly set. [See Saw] If the segment
veneer—saw exceeds about 4: feet in diameter, the hori-
zontal platform or table is not used for guiding the
wood, but a contrivance called the drag. In saw-mills
where veneers are cut, the arrangement of the segment
saw is called a veneer-mill. The axis of the saw runs
in massive brasses, fixed on brick or stone piers; and
if the saw be large, its edge is made to dip into a pit
below the ground. The axis of the saw is connected
or disconnected with the moving power by means of
a fast-and—loose pulley. The log of wood is usually
adzed over to remove sand and dirt, and is then par-
tially levelled to adapt it to the vertical face of the
drag. The log is held by iron fastenings or dogs,
while its surface is levelled by the saw; it is then
glued to a wooden frame containing transverse and
oblique bars, which have also been levelled with the
saw. By this arrangement, the whole log can be cut
into veneers without interruption from the joint.
The timber is carried across the face of the saw by
means of a rack and pinion acting on the drag, which
is supported on a railway extending across the face of
the saw. The axis of the pinion is furnished with a
double train of toothed wheels, and a clutehebox, the
latter capable of being adjusted to 3 positions, by
which the drag may be at rest or be carried slowly
past the saw, or returned quickly back preparatory to
another out. The lever by which these motions are
given is placed just behind the stool on which the
workman is seated. Between every two veneers, the
block requires to be advanced sideways through a
small space equal to the thickness of the intended
veneer. This is accomplished by means of adjusting
screws, which act upon the standards which support
the frame or wooden bars to which the wood is at-
tached. The adjusting screws have worm-wheels at
one end, and are simultaneously moved by a winch-
handle, 50 or 60 turns of which are required to ad—
Vance the log 1 inch, so that the veneers can by this
adjustment be cut to any desired thickness. The thin
veneer as it is cut is guided away from or in front of
the saw by a feather-edged brass guide-plate, fixed
almost in contact with the blade of the saw. As the
veneer is being cut, the workman leads it on to the
guide by means of a thin blunt chisel or spml; and
it passes over the guide through a curved wooden
trough, and when fully detached, it is removed and
placed in a heap of veneers already cut from the same
log. The teeth of the saw are cleared of sawedust by

l
means of a fleeing-stick applied beneath the timber
during the action of the saw.
The number of veneers cutout of each solid inch
of wood varies with the width of the veneers, and the
purpose to which they are to be applied. In general,
when the width of the wood is 6, 12, 18, 24, 30, 36,
4L8, 60 inches, each inch of wood is cut into 15, 14a,
13, 12, 11, 10, 9, 8 veneers.
As the veneers are out they are rough on both
sides, in which condition they are used by cabinet—
makers for veneer-ing articles of furniture. The ope—
rations of veneering consist in glueing the veneer to
the prepared surface, and cleaning and polishing it
when so fixed. Suppose the top of a table or of a
sideboard is to be veneered. The workman first cuts
out his veneers a little larger than the required size to
allow for waste; he also cuts out a caul or board to
prevent the clamp screws from leaving marks, and he
next proceeds to scratch over the surface of the table
or sideboard, and both surfaces of the veneer, with an
iron Zooming-plane, which gives to the surfaces the re-
quired roughness, or tooth, or key, as it is called, for
holding the glue. The clamps consist of strong
wooden bars somewhat rounded on their inner edges,
and connected by iron screw-bolts and nuts. The
surface of the table being warmed, and the veneer and
caul made hot, the table is brushed over with thin
glue; the veneer is also glued and placed 011 the table:
upon the veneer is put the heated caul, and the
clamping bars are next quickly screwed down 3 or 4:
inches apart. The heat of the caul retains the glue
in a fluid state during the screwing down, which ope—
ration brings every part of the veneer into contact
with the table, and forces out most of the glue. The
table is generally left all night before the screws are
removed. For curved work the cauls are also curved,
and the clamp screws are numerous, in order to mul-
tiply the points of pressure.
Veneers are sometimes laid with a veneering ham-
mer, which is a hammer with a very wide and thin
pane; or simply a piece of wood 3 or 4: inches square,
with a round handle projecting from the centre: one
edge of the head is sawn down for the reception of a
piece of sheet-iron or steel, which is made to project
% inch, with a straight, smooth, round edge, and
the opposite side of the square head is rounded to
make it fit the hand better. The table and both sides
of the veneer are toothed, the surface of the table is
warmed, and the outer face of the veneer and the sur-
face of the table are wetted with thin glue or stiff size.
The inner face of the veneer is next glued, and the ve—
neer is held for a very short time before a blazing fire
to make the glue very fluid; the veneer is then turned
down upon the table and rubbed down by hand, seve-
ral men being employed if the veneer be of large size.
The greater part of the glue is then forced out with
the edge of the veneering hammer, which is placed in
the centre of the table, and gradually worked to the
edge. A number of men are employed on this at
once, and in order to keep the glue fluid, as also to
relieve the friction of the hammers, hot size is occa-
sionally applied to the surface of the veneer. When
VENEER-VENEERIN G—VERATRIN E—VICE.
901
the work is judged to be complete, it is tapped all
over with the back of the hammer; if the sound be
anywhere hollow or tachy, the contact is imperfect,
and the hot size and the work of the hammer must
be repeated; or if the glue be well set, the inner
vessel of the glue-pot, or a hot iron, must be applied
to the spot to melt it. Should the glue be in excess
at one spot, the hot iron must be slowly moved to-
wards the edge, so as to form a kind of channel along
which the glue is pressed by the edge of the veneer-
ing hammer.
INLAYING is a species of veneering in patterns
which are cut with the buhl-saw, or piercing-saw,
Fig. 381. [See Bum-wean] As an example of
buhl—work in wood we take the liberty of quoting
Mr. Holtzapifel’s excellent description of the mode of
forming the honey-suckle ornament. “ To make this,
two pieces of veneer of equal size, say of ebony and
holly, are scraped evenly on both sides with the
teething-plane, and glued together with a piece of
paper between, for the convenience of their after—
separation. Another piece of paper is glued outside
the one or other veneer, and on which the design is
sketched; a minute hole is then made with a sharp-
pointed awl or scriber, for the introduction of the
saw, that spot being selected in which the puncture
will escape observation. The buhl-cutter being seated
on the horse, the saw is inserted in the hole in the
veneers, and then fixed in its frame; the work, held
in the left hand, is placed in the vice, which is under
control of the foot, and the saw is grasped in the
right hand, with the fore—finger extended to support
and guide the frame; the medium and usual position
of which is nearly horizontal and at right angles to
the path of the saw. The several lines of the work
are now followed by short quick strokes of the saw,
the blade of which is always horizontal; but the frame
and work are rapidly twisted about at all angles, to
place the saw in the direction of the several lines.
Considerable art is required in designing and sawing
these ornaments, so that the saw may continue to
ramble uninterruptedly through the pattern, whilst
the position of the work is as constantly shifted about
in the vice, with that which appears to be a strange
and perplexing restlessness. When the sawing is
completed, the several parts are laid flat on a table,
and any removed pieces are replaced. The entire
work is then pressed down with the hand, the holly
is stripped off in one layer with a painter’s palette-
knife, which splits the paper, and the layer of holly
is laid on the table with the paper downwards, or
without being inverted. The honeysuckle is now
pushed out of the ebony with the end of the scriber,
and any minute pieces are picked out with the moist-
ened finger; these are all laid aside; the cavity thus
produced in the ebony is now entirely filled up with
the honeysuckle of holly, and a piece of paper smeared
with thick glue is rubbed on the two to retain them
in contact. They are immediately turned over, and
the toothings, or fine dust of the ebony, are rubbed
in to fill up the interstices ; a little thick glue is then
applied, and rubbed in, first with the finger, and then

with the pane of the hammer, after which the work is
laid aside to dry. When thoroughly dryTit only re-
mains to scrape the bottom with the teething-plane,
or, when the work is small, with its iron alone, and
then the buhl is ready to be glued on the box or fur-
niture in the manner of an ordinary veneer, as already
explained; when the work is again dry, it is scraped
and polished. Exactly the same routine is pursued
in combining the holly-ground and the ebony honey-
suckle, and these constitute the counter, or counterpart
huht, inwhich the pattern is the same, but the colours
are reversed. It is obvious that precisely the same
general method would be pursued to make 4: satin-
wood honeysuckles at the respective angles of a rose-
wood box; the veneers for which would then be
selected of the full size, and glued together with
paper interposed. To ensure the exact similitude of
the several honeysuckles, one of them having been
cut out would be printed from, by sticking it slightly
to the table, dabbing it with printing-ink, and then
taking impressions to be glued on the other angles of
the box at their exact places. The counter would
have, in this case, a satin-wood ground, with the
honeysuckles in rosewood. To advance another stage,
3 thicknesses of wood may be glued together, as rose-
wood, mahogany, and satin-wood, and a centre orna-
ment added to the group of 41 honeysuckles. The
3 thicknesses, when out through, split asunder, and
re-combined, would produce 3 pieces of buhl-work,
the grounds of which would be of rose-wood, maho-
gany, and satin-wood, with the honeysuckle and centre
of the two other colours respectively. Such are tech-
nically known as ‘ works in three woods,’ and consti-
tute the general limit of the thicknesses, but the
patterns consist of many more parts than are here
supposed.” 1 See Maneunrnv.
VENTILATION. See WARMING AND VENTILA-
TION.
VERATRINE or VERATRIA, an alkaloid con-
tained in the seeds of Vemtmm sahadilta, and in the
roots of V. 6611165, or white hellehore. It is a white or
yellowish—white powder, with a sharp burning taste;
it is poisonous; and is remarkable for occasioning
violent sneezing. It is insoluble in water, but dis—
solves in hot alcohol, in ether, and in acids: and the
solution has an alkaline reaction. Veratria is said to
contain 034H2206N. .
VERDIGRIS. See Corrnn.
VERDITER. See Corrnn.
VERMICELLI. See Mxcxnonr.
VERMILION. See MERCURY.
VIADUCT. See Barnes—Beans AND RAIL-
noxns—Aqunnucr.
VICE, a well-known contrivance for fixing work
during the filing or otherwise shaping thereof.”

(1) “ Mechanical Manipulation,” vol. ii. As an example of
complex inlaying, Mr. Holtzapfi‘el gives an engraving of a border
of flowers on a. black ground of ebony, with instructions for
making it. The green leaves are of holly, stained green, notched
and engraved. The petals are of holly stained blue, or scorched;
white holly, yellow Zante, and red Brazil wood are also used.
I 2) A large number of vices are described and figured in
Holtzapifel’s “ Mechanical Manipulation,” chap. xxviii. sec. 3.
902
WACKE—WADDING—WAFERS—WARMING AND VENTILATION.
VINEGAR. See Acn'rro Acrn.
VITRIEIABLE COLOURS. See GLASS, Sec. ix.
—-Po'rrnnx AND PORCELAIN, Sec. viii. ix.
VITRIFICATION. See GLASS—POTTERY AND
PORCELAIN.
VITRIOL. See SULPHUR, page 800, note.
WACKE, or Gnxu or Gnnrwncxn, a term adopted
from the German geologists, and applied to some of
the ancient stratified rocks. When the term is applied
to particular rocks, it bears nearly the same relation
to clay slates that argillaceous sandstones and con-
glomerates bear to common clays; “for argillaceous
slate,” as Mr. Phillips remarks, “ by including rolled
fragments or minute grains of quartz sand, with or
without mica, becomes the grauzeae/se, and grauieaehe-
slate of 'Werner and his followers. When the sand
or gravel predominates, so as nearly to exclude the ar-
gillaceous cement, the distinction between grauwacke
and sandstone is almost imaginary, just as, on the
other hand, indurated shale and soft clay-slate are not
always certainly distinguishable.” The grauwacke
rocks lie amidst the primary argillaceous strata, and
form part of the transition series of continental geolo-
gists. The grauwaelce group of De la Beche includes
the Silurian roe/cs of Murchison, and a portion of the
older strata called the Cambrian rocks by Sedgwick.
WVAD, a term applied by miners to a soft black
mineral, the hydrate of the peroxide of manganese.
I/VADDING, a spongy material used for lining
ladies’ dresses; it is made with a lap of cotton pre—
pared by the carding-engine, or lap—machine, [see
CorroN, Fig. 637 1; and is attached to tissue paper
by means of size.
WAFERS. The invention of wafers is attributed
to the Genoese; but long before their application to
the sealing of letters, they were made by the pastry-
cook in the form of a thin curled-up cake. Indeed, a
pastry-cook was formerly called a wafirer. According
to Beckmann, the oldest seal with a red wafer is on a
letter written by D. Krapf, at Spires, in the year
1624, to the government at Bayreuth. It appears
that wafers were not used during the seventeenth
century in the chanccry of Brandenburg, “because
people were fonder of Spanish wax.” By an order
dated 1716, the use of wafers in law matters was for-
bidden in the duchy of Weimar ; but this order was
abolished in 17a?“ See SEALING-WAX.
The French term for wafers, pains a eaeheter, indi-
cates the materials of which they are made. Wafers
are small disks of dried wheaten paste, to which an
adhesive property is instantly communicated on the
addition of moisture. In the manufacture of wafers
fine wheaten flour is formed into a smooth paste, with
the addition of colouring matter and sometimes of a
small quantity of white of egg and isinglass. This
paste is baked in thin layers, between two plates of
iron attached to handles, which are hinged together
like snuffers or curling-tongs. The lower plate,
which is furnished with a slightly raised ledge, forms
a mould for the paste. The plates are warmed, and
slightly greased, and a portion of the paste being
poured into the lower plate, the top plate is shut

down, whereby the paste is formed into a thin layer
of equal thickness, the superfluous portion being
squeezed out. The instrument is then held in the
fire for a few seconds, when it is perfectly baked, and
by exposure to the air it soon becomes dry and brittle.
A number of these plates of paste being collected
into a heap, the wafers are cutout by means of hollow
punches of various sizes. Some of the mineral
colours employed to colour wafers being poisonous,
the refuse is sold for the purpose of destroying rats
and other vermin.
Medallion wafers, containing a classic design on
a ground of a deeper colour, were in fashion some
years ago. They were formed in the following
manner a—Pure glue was dissolved in water, and the
colouring matter added. A gem, seal, or medallion
was next moistened with a weak solution of gum, in
which an opaque white, or other colour had been dis-
solved; this coloured gum water was carefully wiped
off the smooth uncut surface of the seal, and a small
quantity of the coloured glue was poured over the
seal, and left to dry at a gentle heat. In drying, the
glue and gum contracted, and were thus easily sepa—
rated from the seal, thus forming a wafer not thicker
than writing paper, and affording a beautiful imitation
of the device, the coloured gum giving the figure, and
the glue the ground. On wetting the back of the
wafer, it adhered to and secured a letter just like an
ordinary seal.
The French isinglass wafer was prepared by dissolv-
ing isinglass in water, and pouring it upon glass plates
with raised borders, previously smearing the plates
with ox-gall, to prevent the isinglass from adhering.
Various colouring matters, and even perfumes, were
mixed with the fluid isinglass. When the film on the
plate was evenly distributed, a plate of glass was
placed upon it, and the film was thus moulded into a
fine delicate sheet: before it was quite dry, it was cut
along the edges, and separated, and afterwards cut
into wafers in the usual manner. These wafers were
exceedingly thin, and far more adhesive than common
wafers. Gelatine wagers are now largely manufactured
in a similar manner. See GELATINE.
WALKING WHEEL. See Pnnoinn'rnn.
WALL. See BRICKLAYING—MASONBY—BRIDGE
—-B.oxns AND RAILROADS.
WARP. See Wnnvrne.
WARMING AND VENTILATION. The art
of warming or of ventilating a building is not a diffi-
cult one; but the art of warming and ventilating is
extremely difiicult, and cannot be said to have at-
tained to anything like perfection. And yet there is
no art of greater importance, for on it depend the
health, the comfort, and much of the prosperity of
man, and of the animals which he domesticates for
his use and profit.
In order to arrive at satisfactory results in the
practice of this art, it is necessary to be well ac-
quainted with the chemical conditions of the problem
which is to be solved. Now it is well known that the
combustion of fuel and the respiration of animals are
processes almost chemically identical; they require
WARMING AND VENTILATION.
903
for their successful performance a constant supply of
oxygen gas, which, under ordinary circumstances, is
afl‘orded by the atmospheric air. The carbon of the
fuel which we burn for the sake of heat, and the car-
bon of our candles, oil—lamps and gas-jets which we
burn for the sake of light, is converted into carbonic
acid. So also with respect to the food consumed by
animals, a portion of its carbon is employed in the
generation of animal heat; and during its slow
combustion, is converted into carbonic acid. While
oxygen gas is passing inwards through the membrane
of the lungs, carbonic acid is passing outwards through
the same membrane. The oxygen of the air is ab-
sorbed by the blood in the ultimate vessels of the
lungs, and in some unknown state of combination
reaches the extreme subdivision of the arteries, where
it unites with a portion of carbon and forms carbonic
acid gas, which gas also, in some unknown state of
combination, is retained in the venous blood, until it
is expelled in the lungs and oxygen absorbed in its
stead. A man of ordinary stature consumes in the
course of 24 hours, 9 ounces troy, of carbon; the
consumption of oxygen in this process is equal to
24: ounces, or 194 cubic feet; the quantity of air
vitiated in the process amounts to 97'2 cubic feet, and
the product in carbonic acid to 33 ounces. The pro-
ducts of combustion and of respiration consist there—
fore chiefly of carbonic acid mingled with the nitrogen
of the air, both irrespirable gases, which, unless largely
diluted with air, would, if taken into the lungs, pro-
duce death. Now, in the economy of nature, it has
been wisely ordained that these poisonous products
of such extensive processes as combustion and respi-
ration shall form an aerial manure to the vegetable
kingdom, supplying it with materials for growth; and
the organs of plants are so constructed, that in appro-
priating and assimilating this aerial manure, they re-
turn fresh supplies of pure oxygen to the atmosphere;
they inhale carbonic acid, and exhale vital air. Nature
has also wisely provided that the air vitiated by com-
bustion shall have a strong ascensive force due to its
high temperature, in virtue of which it ascends into
the atmosphere, where it is wafted by the winds, or
absorbed by the rain, and thus distributed over the
vegetable kingdom. So also with respect to the pro-
ducts of respiration. The vitiated air as it leaves
the chest, has nearly the temperature of the blood,
viz. 98°, and thus being specifically lighter than the
surrounding air, it ascends and escapes to a higher
level. In the open air the process is perfect, because
there is no impediment to the ascent of the vitiated
air; but in rooms, halls, churches and similar enclo-
sures, as ordinarily constructed, the vitiated air,
whether arising from combustion or respiration, rises
up to the ceiling, and cannot escape, but accumulates,
becomes cooler, and thus descends and mingles with
the fresher air which occupies the lower level.1 The
inmates of the apartment thus have to inhale an

(1) A good illustration is afforded of this process in blowing
out a tallow candle. The hot nauseous vapour ascends to the
ceiling, spreads all over its surface, becomes cooled, and then de-
scends to taint the air of the whole apartment.

atmosphere which is every moment becoming more
impure; and it is only because the doors and windows
do not fit tightly that suffocation does not result.
But what an amount of suffering is endured in every
public assembly, and in most private apartments, from
the occupants having to inhale the poisonous pro-
ducts of combustion and respiration, mingled as they
are with animal efduvia of the most offensive descrip-
tion! It is only because these products are invisible
that they fail to attract attention, except on the part
of chemists, and certain intelligent persons who be-
lieve that chemists have rightly interpreted the laws
of nature. In fact, the products to which we refer
are excrements of the most offensive and deadly kind,
which once discharged from the system cannot with
impunity be admitted into it again.
If every ceiling were provided with openings for
the escape of the vitiated air from the room to the
outside of the building, we should be spared many a
headache, many a nervous attack, many a fever;
our lives would be more enjoyable, our intellects
clearer, and our morals purer; for we have no doubt
that the breathing of a pure air is as necessary as the
enjoyment of good food and competence to the pos-
session of a cheerful temper and an innocent frame
of mind. But there are difiiculties about having an
opening in the ceiling with a channel leading to the
outer air. 1. The room would not be so warm, for it
is obvious that the escape of hot, although vitiated,
air would materially lower the temperature of the
apartment. 2. Occasions might arise when the
channel would bring in cold air and pour it down in
a stream upon the heads of the inmates, instead of
letting out hot air. 3. Such a channel would admit
noise from the street. We will endeavour in the
course of this article to show how this contrivance
may be modified, so as to overcome these objections.
The principle, however, is sound, that in ventilating
an enclosed space, the hot vitiated air must find an
exit at the highest point of the enclosure, and the
supply of fresh air be admitted at or near the lowest
point.
We are so accustomed to the open fire—place, and
the extravagant waste of valuable fuel which it en-
tails, that we are apt to look with suspicion on other
contrivances for warming our rooms. It is necessary,
however, to inquire a little into the various methods
of obtaining artificial heat before we can atfirm that
the open coal fire is the best method. The first part
of this article will therefore be devoted to a notice of
various contrivances for warming buildings; the se-
cond part to the means of ventilating; and the third
part to the art of warming and ventilating.
Sncrron L—On' THE vanrous Means ADOPTED ron
run wnnnrme or BUILDINGS.
1. By tire open fire—That large proportion of the
human race which inhabits extratropical climes, and
requires the use of means for the production of arti-
ficial heat during a greater or less portion of the year,
is influenced both morally and physically by the faci-
lities with which fuel can be procured. Where the
9041
WARMING AND VENTILATION.
climate is severe and fuel is scanty, men suffer great
privations, and the race declines both in mind and
body. 'Where fuel is abundant man thrives; his
houses are larger than in the former case, and he can
afford to shelter comfortably many domestic animals,
so that he is not pinched for want of food. It is
stated that in France, where fuel is scarce, the average
height of a man does not exceed 5 feet 4. inches; that
in the Netherlands, where fuel is more abundant, the
average height is 5 feet 6%.,- inches ; that in England,
where fuel is abundant, the average height is upwards
of 5 feet 9 inches, and that in Sweden, where wood is
very abundant, the peasants are tall vigorous men not-
withstanding their uncleanly habits and the rigour of
the climate.
In some parts of China where fuel is scarce, the
inhabitants resist the cold of winter by means of
warm clothing, and. this is a safer method than that
which we are accustomed to adopt, since with them
the defence is constant and uniform, while with us the
indoor clothing is thin, and the atmosphere of our
rooms is raised to summer temperature. Provided a
person be well clothed he can breathe the coldest air
with safety and even with an exhilarating effect, as in
skating or in walking briskly. We may enjoy a com-
fortable warmth in bed while the air of the room is
cold enough to freeze water. Hence it is better to
dress so as to feel comfortably warm in a room heated
to 60° or 62°, which it is not dangerous to enter or
to leave, than to dress lightly in a room heated to
70° or more, and which is liable to sink to 50° or
less.
In most cold countries the poor obtain warmth by
some means or other which renders the air almost
irrespirable. The poor lace-makers of Normandy work
all night in houses where cows are tethered, for the
sake of the steaming animal heat. The Laplander
during two-thirds of the year occupies a small hut
heated by a smoky lamp of impure oil. The Green-
lander occupies a larger and better contrived hut, but
it is often occupied by half a dozen families, each of
which is provided with a lamp, and a traveller remarks,
that the effect of this arrangement “is to create such
a smell, that it strikes one not accustomed to it, to
the very heart.” In Persia, a large jar, named a
lrom'cy, sunk in .the earthen floor of the room, is filled
with wood, dried dung or other combustible, and when
sufficiently charred the mouth of the vessel is shut in
with a square wooden frame, and the whole is covered
with a thick quilt, around which the members of the
family sit, placing their knees under it so as to allow
the hot vapour to insinuate itself into the folds of
their clothing. When one desires more warmth he
reclines with the quilt drawn up to the chin. In
some parts of Spain charcoal is burnt in a flat open
brass pan about 2 feet in diameter, raised afew inches
from the ground by a round wooden frame for support-
ing the feet of those who sit near. The charcoal
brazier is avery ancient method of warming an apart-
ment: the Greeks of old adopted it, and bestowed
much of their exquisite taste in improving the form of
the brazier and adorning it with sculptured figures.

We still admire the elegant bronze tripods of the
Romans, supported by satyrs and sphinxes, with a
round dish above for the fire, and a small vase below
for holding perfumes. It is strange that the charcoal
brazier should still continue in use; it has long been
employed as the instrument of suicide, and has also
led to many involuntary deaths; and the cause is well
known. A pound of charcoal in burning consumes
2% lbs. of oxygen, which is the quantity contained in
between 13 lbs. and 14. lbs. of atmospheric air. A
room 20 feet by 13 and 10 feet high contains about
200 lbs. of air, and as the combustion of 1 lb. of
charcoal produces 31-“; lbs. of carbonic acid, which by
mingling with the rest of the air of the room renders
at least 36 lbs. of air unfit for respiration, making in
all about 50lbs. weight of air, it is evident that in a
room thus heated, death will ensue unless the ventila-
tion be sufiicient to change the whole of the air many
times within the hour.
The Romans, however, adopted a much better plan
than that of the brazier for heating large rooms, viz.
the izygoocaast, or a system of fines conducted belowr
the floor, the fireplace being outside the building. A
similar contrivance is still in use among the Chinese
in and about Pekin. The fireplace is formed against
the exterior wall of the room which is to be heated,
or in an adjoining room. From the fire or the fire-
chamber proceeds a main fine opening into a horizontal
line a 6, Fig. 2230, from which proceeds a second fine
00? at right angles
thereto; these fines
are perforated at in-
tervals for the pur-
pose of diffusing
the smoke and hot
air over the under .
surface of the tiled (1
floor, and the smoke
finally finds an exit Fig‘ 2230'
by two horizontal flues cf attached to the side walls.
The tiles of the floor, being bad conductors of heat,
retain sufficient warmth for domestic comfort long
after the fire is extinguished. Benches and sleeping
places are similarly warmed. They are built hollow
with bricks in a square or oblong form, and communi-
cate with the fines. Inferior or small refuse coal is
used for this source of heat: it is mixed with a
compost of clay, earth, cowdung or other refuse vege-
table matter; then formed into balls and dried in the
sun. These balls give out very little smoke, and are
well adapted for the purpose intended. ,The hori-
zontal fine is termed a ti-lrcmg ; in the tony-[mag the
fine is vertical, and approaches the chimney in its form
and action.
Before the introduction of this important contriv—
ance, the chimney, the old baronial hall was heated by
a fire in the middle, and in the roof above was a turret
or louvre filled with boards arranged so as to ex-
clude the wind and the rain and allow the smoke to
escape. The houses of the small land~holders and
farmers were usually one story high ; the hall and the
kitchen formed one apartment, which was open to




WARMING AND VENTILATION.
905

the timbers of the roof, and 'm‘some cases was fur-
nished with a louvre, and a window that could be
closed with a shutter. Cottages had no louvre. The
castles which were built about the time of the Con-
quest were several stories in height, and the roof being
a flat terrace, the central hearth and louvre could not be
constructed. The fire hearth was therefore transferred
to the wall, which was perforated to afford an exit to
the smoke, and thus the chimney came gradually to be
introduced. See CHIMNEY.
Wood was the ordinary fuel up to the seventeenth
century, or long after the introduction of the chimney.
It was burnt on a spacious hearth, the logs being
"Hill" “any
___“
‘__—
Fig. 2231.
confined between 2 standards of the andiron, Fig.
2231, their ends resting on the billet bar so as to
allow air to be admitted be-
low. The standards were
variously ornamented with
‘ brass rings, knobs, rosettes,
heads and feet of animals,
and grotesque forms. In
kitchens and the rooms of
common houses the andiron,
as its name implies, was of
iron; but in the hall the
standards were of copper or
brass, and sometimes of
silver. The capacious re-
ceptacle was furnished with
seats on each side of the
hearth, and the chimney
corner was the post of he-





Fig 2233.
near. The place of assembly of the family was round
the hearth, which thus becoming associated with ideas
of comfort and conviviality, the word hearth became
synonymous with home. In smaller rooms where the
fire was made in a wide and deep recess each standard
was fixed into the back of the hearth by alateral bar,
as shown in Figs. 2231, 2232, 2233, which represent

an elevation, section, and plan of the fireplace in the
hall at Vicar’s Close, Wélls.
So long as wood was abundant, coal was not used
in Great Britain: indeed, it was long held to be in—
jurious to health; but towards the close of the 13th
century, however, coal was imported into London
from Newcastle for the use of brewers, smiths, and
others, who consumed large quantities of fuel. Its
use was regarded with suspicion, and in 1306, par-
liament petitioned the king to prohibit its employment
in the city. A royal proclamation was accordingly
issued, forbidding the use of coal. This failed in its
object, and a commission was issued for the purpose
of ascertaining the names of the persons that burned
sea-coal within the city and its neighbourhood, in
order that they might be punished, first by fine, and,
on a repetition of the offence, by a demolition of their
furnaces. But as these severe measures failed to
effect the object, a law was passed making the burn-
ing of sea-coal within the city a capital offence, and
permitting its use only in the forges of the neigh-
bourhood. In the reign of Edward I. a man was
actually hung for burning coal in London. It was
not until the commencement of the 17th century
that the use of coal became general. Ladies supposed
that it injured their complexions :1 and they even
objected to partake of food that had been cooked at
a coal fire.
There is no doubt that the large chimney recesses,
and chimneys adapted to the burning of wood fuel,
were not well contrived for the combustion of coal.
Improvements, however, were first made in hearths
where wood was burnt. Louis Savot, in his Treatise
on Architecture, remarks that only large rooms are
free from smoke, and that when fires are kindled in
small rooms a door or window had to be left open to
prevent the air coming down the wide flue and driving
the smoke into the room. To correct this, Savot
raised the hearth about él: inches, and lowered the
mantel, so as to make the opening of the fireplace
about 3 feet high: the width between the jamhs was
reduced to 3 feet,'the jambs from the mantel were
to be carried up sloping to the waist, or where the
flue begins to be of uniform width, and the opening
of the fireplace was formed like an arch. When the
fireplace could not be conveniently altered, a plate of
iron, of similar width and length with the hearth, was
perforated with small holes, and fixed 3 inches above
the tiles of the common hearth: 9 inches above
this perforated plate was placed a “grille de fer” of
the same length as the billets to be burned. The
wood was placed on the grate, the charcoal on the
perforated plate, and the hearth received the ashes:
the air, rising through the small holes, promoted the
combustion of the charcoal, and this assisted the
burning of the wood, so that soon a draught was
established up the chimney, and the smoke was

(I) This idea has been so prevalent in France, almost up to the
present time, that a very few years ago, on the occasion of the
English Ambassador at Paris giving a grand entertainment, 11°
ladies attended in consequence of a report that his Lordship used
coal fires.
906
WARMING AND VENTILATION.
effectually discharged into the air. The fireplace used
to warm the “ Cabinet des Livres” at the Louvre is
shown in Figs. 223a, 2235. The hearth was a thick






- \:.~.r -. ‘Ea->5’. if d.“ -g‘J‘I" :Efi a >-> - r -- 1 ‘AIS' ' v_~$m!
1 _
.» p v V ‘ —j
gag ‘ a". g g .
“it. : "‘ N“ ~_ ‘-- ~ .b p.
".- h x __ w" was "‘ "‘" ‘- ' “ s- (
\“2'3‘ “ " \ j . - b.
i . ‘\ IL
' mm?’
' W



m
Fig. 2234.
iron plate placed above the
old hearth with an inter-
val i of 3 inches between.
The two sides or earrings
of the fireplace were also
formed of thick iron plates,
placed 3 inches from the
jambs. The spaceiat the
back and the spaces at the
sides communicated with
the interval i under the
hearth. Two pipes or
channels 0 opened from
these hollow spaces into
the room at 0, which spaces
could be closed at pleasure. When the fire was
burning, the iron hearth and the plates which
formed the sides and the back became heated. The
cold air, entering at the lower openings aa at the
floor, into the space i, became heated by the hearth,
and rising into the spaces at the back and sides,
was further raised in temperature; it then entered
the channels 0, escaped at 0, and became diffused
through the room.
Savot also describes a plan for heating 2 adjacent
rooms by means of one fire. The fireplaces of the 2
rooms are separated by a plate
of iron, as shown in Fig. 2236;
and a fire being made on one
hearth of one fireplace heats the
plate, and this, by radiating its
heat, warms the air of the other
room, the fine of which is closed.
If the second room have no
chimney, it may still be warmed
by making an opening in the
wall at the back of the fire of



Fig. 2286.
‘the first room, and closing it with an iron plate.
In the year 1713 the Cardinal Polignac published,
under an assumed name, a treatise on the art of

warming rooms, which deserves especial notice.1 In
his preface he thus concisely states his method of
warming. “ A plate of iron or copper bowed or
bended after such a manner as is not at all disagree-
able to the sight; a void behind, divided by certain
small iron bands or partition plates, forming several
spaces that have a communication one with another;
a little vent hole in the middle of the hearth. a regis-
ter plate in the upper part of the funnel, and, for
some shafts, a capital on the top, make up the whole
construction and workmanship of our modern chimney.
To be able to kindle a fire speedily, and make it, if
you please, flame continually, whatever wood is burn~
ing, without the use of bellows; to give heat to a
spacious room, and even to another adjoining, with
a little fire; to warm one’s self at the same time 011
all sides, be the weather ever so cold, without scorch-
ing ; to breathe a pure air always fresh, and to such
a degree of warmth as is thought fit; to he never
annoyed with smoke in one’s apartment, nor have any
moisture therein; to quench by one’s self, and in an
instant, any fire that may catch in the tunnel of a
chimney; all these are but a few of the effects and
properties of these wonderful machines, notwithstand-
ing their apparent simplicity. Since I used this sort
of chimney, I have not been troubled one moment
with smoke, in a lodging which it rendered before
untenable as soon as a fire was lighted; I have always
inhaled, even during the sharpest seasons, a fresh
air like that of the spring. In 1709, water that froze
hard everywhere else very near the hearth, did not
congeal at night in my chamber, though the fire was
put out before midnight; and all that was brought
thither in the day soon thawed; neither did I ever
perceive the least moisture in winter, not even during
thaws.”
Although this treatise was written 150 years ago,
the opening remarks are still applicable, coal being
substituted for wood. The author says :—-“ It seems
that those who have hitherto built or caused chimneys
to be erected, have only taken care to contrive in the
chambers certain places where wood may be burnt,
without making a due reflection that the wood in
burning ought to warm those chambers, and the
persons who are in them; at least, it is certain that
but a very little heat is felt of the fire made in the
ordinary chimneys, and that they might be ordered
so as to send forth a great deal more, only by chang-
ing the disposition of their jambs and wings.” The
methods by which a fire may communicate its heating
effect to a. room, are correctly stated to be by radia—
tion, by reflection, and by conduction. Now as radiant
heat is reflected according to the same law as light,
i.e. the angle of incidence is equal to the angle of
reflection, it follows that, in a fireplace with straight
jambs, very few of the rays are reflected into the

(1) This treatise, published under the name of Gauger, is en~
titled, “La Méchanique du Fen, cu 1’AIt d’en augmenter les
efi'ets, et d’en diminuer 1a dépense ; contenant 1e Traité de Nou~
velles Cheminées, qui échauffent plus qne les Cheminées ordi-
naires, et qui ne sont point sujettes a fumer.” This treatise was
reprinted at Amsterdam, in 1714, and a. translation of it by
Dr. Desaguliers appeared in London, in 1716.
WARMING AND VENTILATION.
907
room. Thus, suppose a fire, fi Fig. 2237, to be made
inf an ordinafy
chimney, AB, 6 a,
of which the
‘7A- jambs, an, be,
are parallel, the
_ A ray of heat, f e,
will be reflected
back in M; the
ray f H upon
itself inf; the rayfr in u; and the ray j'LinP;
and this is the only ray that can be reflected into the
chamber, the others being to the back, or up the
chimney, or among the fuel, and contribute in no way
to the useful heating effect of the fire. In cases,
however, where the jambs are formed of plaster, there
is not even this reflection, for the heat, falling upon
the dull surface, is absorbed. The author then de-
scribes what ought to be the correct form of the
jambs :—“Geometricians,” he says, “ are sensible
that all radiuses which set out from the focus of a
parabola and fall upon its sides, are reflected back
parallel to its axis. If, therefore, you take on the
bottom of a chimney hearth, AB, be, Fig. 2238, a
length, cle, equal

Hillfisa
is,‘
I
I
I
I
I



E“ to that of the
wood designed
IIII 4' to be burnt, for
[E3 example, of half
a log or billet,
Fi_q_ 2233_ which, at Paris,
is 22 inches;
from the points 0 a, let fall the perpendicular c 1), c d,
which may be the axis of two semi—parabolas, whereof
c c are the vertices and A a (the distance between
which is the breadth of the chimney) each of them
one of their points; that done, you are to line with
iron or copper plates the two parabolical sides A0,
a c, of the chimney, and make the lower part of the
concave parallel to the horizon, and as large as it can
be, only leaving 10 or 12 inches for the aperture
of the chimney funnel. By this arrangement, as much
of the heat as can be will be reflected, for all the
rays of heat from the focus Ff of each semi-parabola,
as f g, f/a, fz',fl, &c., will be reflected back parallel
to the axis a a? in m, 72, 0, p, and consequently, pass
into the room. So also, all those rays, E H I, which
are not reflected back parallel to the axis, will never-
theless be reflected into the chamber or very nearly
so. Besides this, the jambs being so much nearer the
fire than is usual, will soon become heated, and reflect
a larger number of rays.”
All draughts in the room towards the fire were
avoided, by introducing a sozgflet, or blower, noticed
in Savot’s stoves, Fig. 2234!- Its opening was situ-
ated at 2, Fig. 2238, in the centre of the hearth, 10
or 12 inches below the plate on which the fuel was
burned, and communicated with the open air by a
channel from ‘dc to 6 inches square. The opening in
the hearth was furnished with a metal frame, on
which was hinged a trap door, or valve, opening
upwards; the upper surface of this valve was fur-

nished with a button, which could be grasped with
the tongs, and aismall bolt beneath could then be
drawn back, or closed with the button with which it
was connected. The sides of the valve were formed
by two thin sectors of iron, which guided the current
of air through the channel, and confined it within
narrow limits. Two springs in the frame pressed
against the sector sides, and kept the valve open at
any desired angle; of course, when the valve was
shut and bolted, there was no current.
A number of fireplaces are described in this treatise,
all of which are furnished with parabolic jambs and
the soufllet; but the back, the jambs, the hearth, and
the mantel, are -- > '


.' “7111331. - 'llllthlmu ‘RH 131 '"KHIEIE-a




also made hollow, / ,7. W '3 g a
for the purpose 7' \ f p 11.
of pouring a co- [ ,, l I
pious supply of ll m m m 1‘
heated air intot \ 1‘ gr
the apartment. a _> y, N
These hollow
spaces, named E
caliducts or merm- Fig‘ 2239'
ders, are in one arrangement, Fig. 2239, formed by
perpendicular divisions. In another variety, Fig.
2240, they are
horizontal. Here
the hearth is also
hollowed out and
divided into a
series of square
spaces. The cold
air entering at (1,
follows the direc- “f
tion of the ar-
rows, and escapes into the room at 12; h is the
hearth, s the smoke fine, and m m’ m" the caliducts.
The supply of hot air into the room was regulated
by a valve in the air channel, formed on the principle
of the four-way cock. [See STEAM ENGINE, Fig.
20411.] A small cylinder, 00, Fig. 224.1, moved
within another fixed cylinder. The revolving cylinder
had 2 apertures, 0 0, and
the fixed cylinder 3 aper-
tures. The axis of the re-
volving cylinder passed
through the cover of the
fixed cylinder, and had a
small lever or needle at-
tached to it, by means of which the cylinder was turned
by the hand into certain positions marked on a small
dial. When the apertures, 0 o, in the revolving
cylinder coincided with those in the fixed cylinder,
the external air from the channel was admitted into
the caliducts in the chimney back: by turning the
revolving cylinder into another position, the cold air
was excluded from the caliducts, and admitted directly
into the apartments. The cylinder could also be
placed so as to shut 05 the cold air both from the
caliducts and from the room. In this way the air of
the room could be tempered according to the wants
and feelings of the occupants.




Fig. 2240.


Fig. 2241.
908
WARMING AND XENTILATION.
The arrangement which the Cardinal preferred is
represented in the following figures. Fig. 2242 re-
/ /
f e ‘\se .. \\\\$i\\\'\\
/' // ‘TL


/Zv_
//


//
‘ in


Fig. 2242.
presents a horizontal section of the fireplace, and
Fig. 2243, a vertical section. The hollow metal case
forming the back of the chim-
/ ‘3
Elp/ ney is divided into 3 or more


caliducts, p g r, each 4: inches
wide and 6 2 inches broad,
placed about an inch from the
back wall of the hearth recess,
with its lower edge, m, about
2 inches above the surface of
the iron bottom plate or hearth,
a. The jambs, w, lined with
iron or brass plates, are formed
in a parabolic curve, and solid
I at the back. The channel .r,
Fw- 2243- conducting the external air into
the caliducts, is 9 inches on the side; and the
blower c, furnished with its valve, forms an aperture
3 inches long and 2% wide, but instead of being
supplied with air from the outside by a separate
channel, the air is derived from the channel z.
The air-valve a: is placed at the junction of the
cold air channel with the caliducts; and the aperture
.2, through which the warmed air enters the room, is
fitted with a sliding valve, to close the warm air
aperture. The action of this apparatus is as follows :--~
The small wood on the hearth being lighted, and the
valve of the soufilet c lifted up, the logs soon begin
to kindle into a good fire; the smoke and flame rise
into the space between the back, 12 gr, and the wall
of the hearth, and, after heating the iron back of the
caliducts, escape into the fine. In the meantime,
the other face towards the room is also quickly heated
by the flame and smoke. The valve being adjusted
to admit the external air into the first caliduet, it
flows thence into the second and third caliducts,
receiving fresh accessions of heat in its progress, until
it escapes at 2, into the apartment, which it speedily
warms.
For large apartments, these fireplaces may be
erected in the middle of the room, and two may be
set back to back, with one series of caliducts for both,
so that the air will be heated, whether the fire be
kindled in one or both. When kindled in both, the
heating effect will, of course, be greatly increased.
So, also, two adjoining rooms may be heated by one
fire, provided the hearth recesses are placed back to
back; for, by making a fire in one room, the heated
air from the caliducts may be discharged into the
other; or by carrying a pipe from the caliducts through
the wall into an adjoining room, or through the ceiling


into an upper room, an agreeable and a sufiicient
warmth may be distributed.
Subsequent writers of repute have acknowledged
the great merits of the Cardinal’s treatise. PFranlilin
admitted the great assistance it had afforded him; and
the improvements in stoves, introduced by Count
‘Rumford, are similar in principle to those suggested
by this book. The Pclignac fireplaces were con-
structed for wood fuel. Dr. Desaguliers modified
them so as to admit of coal being used in them, and
they were getting into general use in England, when
an outcry was raised that “they burnt the air,” and
they fell into disfavour.
The chief improvement introduced by Count Rum-
ford (whose stove has popularised his name,) was to
contract the area of \\ \\\ \\\\\\\\\\\\\\\\\\\\


the fire—chamber, \
§ \
and to place a flat . \
surface in each in- \ terior angle, as x
shown in the plan, \ ________________________
Fig. 22414:, so as to
reflect into the room that portion of heat which in
the old square grates escaped up the chimney. The
threat of the chimney was also much diminished in
size, and the breast 6, Fig. 224:5, ‘“
rounded off so as to allow the
smoke to ascend more readily. h When the chimney was to be swept
the plate or fiagstone p was re- \\
\\\
moved so as to widen the throat.
To obtain the most effect from
the fuel, Rumford recommended
that the sides of the fireplace be
fixed at an angle of 135° with
the back of the grate, or at an
angle of A5° with a line drawn
across the front of the fireplace,







\
\



.Fz'g. 22‘l5\.\“
such as the dotted line in Fig. 224240. These angular
covings are to be of some badly conducting material,
such as fire-clay polished with lampblack. Circular
covings are objected to on the ground that they
produce eddies or currents which would interfere
with the free ascent of the smoke; and ltumford
also objected to the old form of registers or metal
covers for a similar reason, and also because by
sloping upwards towards the back of the fireplace
they caused the warm air from the room to be
drawn up the chimney, and thus interfered with
the passage of the smoke. These registers were
afterwards altered so as to be lower at the back than
at the front of the stove; but they should be brought
down lower than they are usually placed, and be at
an angle of 459, in which case much of the heat
would be reflected into the room. Rumford also
greatly diminished the size of the grate, and he con-
sidered the best proportions for the chimney recess
to be attained when the width of the back was equal
to the depth from front to back, and the width of the
front or opening between the jambs 3 times the width
of the back.
The best form of register stove of moderate size for
“WARM—DIG AND VENTILATION.
902
diffusing the heat into the room is shown in Fig. 224.6.
The sides A B, n 0, form a right angle, and the bars 5 6’
describe a quadrant of a
circle of which the ra-
dius is half the length of
_A. B. If Rumford’s rule
of making the back 5d
the width of the front is
to be followed, take ad
of A B, which will be 13 a, and draw as parallel to A c.
In this way the sides of the stove form an angle of
135° with the back, and all the rays of heat which
impinge on these sloping sides are reflected into
the room in front of the stove in right lines. The
falling cover or register top should also form an angle
of 135° with the back, and will thus send heat down
into the room.
It has been calculated that the waste of fuel in the
open fireplace with square jamhs is about %ths, or ac—
cording to Rumford i'é‘ths. A loss of more than
half the heat is said to be carried off in the smoke;
about ig-ths of the heat is carried up the chimney by
the current of air which enters the chimney between
the fire and the mantlepieee. The soot is estimated
at gth of the fuel; so that g-ths being carried off in
smoke; Eds in the warm air of the room carried up
the chimney, and am lost in soot, there is a total
loss of gths of the fuel consumed or of the heat pro-
duced. An open fire also produces very unequal
heating effects at different distances; it engenders
cold draughts from doors and windows; a cold foot
bath to the feet; deficient ventilation; smoke and
dust; loss of time in lighting fires, and danger to
property and to the person.
2. The close stove. In places where fuel is scarce
the close stove is used. Fig. 224.7 represents the
Dutch, or simplest form of
stove. Near the bottom is a
grate for the fuel, which is in-
troduced by the door above;
the lower door opens into the
ash-pit, and by opening this
more or less the draught can
hip? be regulated, for the air which
/N_:/ L feeds the fire must pass up
"“I M91247, through it: thus the whole
body of the stove, which is of iron, soon becomes
very hot, and by extending the SllCBi’r‘ll'OIl flue pipe
to a considerable length in the space to be heated,
the products of combustion are made subservient
to the general heating effect on their way to the
chimney. It must, however, be admitted that the
air of a room heated in this way acquires a burnt, and
often sulphurous smell, and becomes negatively elec-
trical; it becomes also very dry, and shrivels up
organic substances. Persons habitually breathing
such air are subject to headaches, giddiness, and other
unpleasant symptoms. This stove is, however, use-
ful to laundresses and others who employ it for
heating irons or for drying. It is made of an orna-
mental form for halls, &c., and when furnished with
a vase for containing water its use is less objectionable.



Fig. 2246.


The fine, however, is apt to become overheated, and
thus lead to danger.
What is called the American stove, Fig. 2248, con—
sists of a square, j
close, iron box,
mounted on {\W

short iron legs,
with a vessel of
water on it to
keep the air
moist.‘ Beneath a
the door is a pro-
jecting plate:
wood fuel intro-
duced at the
door is burned,
and the flame
passing along in the direction of the arrows to the
chimney, heats an inner box or oven, the door of
which is at the side. Within the large door is a
smaller door for regulating the draught.
In the north of Europe the stove is constructed
with a view to the economy of fuel, while the heating
effect is considerable. The fuel in the fireplace is
surrounded by fire-stone, bricks or other bad eon-
ductors of heat; the air admitted to the fuel is regu-
lated by valves in the doors which enclose the ash-pit
and fire-chamber, both doors and valves fitting ae-
curately: the gaseous products of combustion in
escaping from the fuel are brought into contact with
a meandering flue formed of glazed tiles, and present-
ing a large amount of surface to the air of the room
which is to be warmed; the smoke is admitted into
the chimney with as small a velocity or at as low a
temperature (not exceeding 150°) as is consistent
with the maintaining of a high temperature in the fire»
place. The general form of stove adapted to these
conditions is shown in Fig. 2M9. It consists of a
quadrangular box A B c n,
the size of which in the di—
rections A c, B D, is adapted
to the space to be heated;
but the inside width from
front to back is not less
than 10 inches, and seldom
exceeds 20. The whole
included space is divided
by means of partitions.
The lowest chamber is‘ con-
tains the fuel: this is
placed on the bottom of
the stove, which does not contain a grate. cl is the
door of the fireplace, and in it is a small wicket w.
The roof of the fireplace extends to within a few in-
ches of the further end, there being only a narrow
passage r for the flame. At the distance of about
8 inches above the partition is‘, is a second parti-
tion 2, 2, extending nearly to the other side A c,
leaving only a narrow passage for the flame. The
partitions 3, 4:, 5 and 6 occur at intervals of 8
inches, with passages at the ends alternately disposed,
the last communicating with the vent in the flue j;
‘w,
"651%
My


-—
Fig . 2248.
d


Fig. 2249.
910
WARMING AND VENTILATION.
the draught being regulated by an iron plate or
damper stretching across f. If the fuel be of wood,
as it usually is, and the vent is situated in the room
while the fireplace is in an outer lobby, the vent is
closed by a sort of pan or earthenware bowl inverted
over it, with its brim buried in sand contained in a
groove formed round the hole. The stove is usually
situated in a corner of the room so arranged that the
chimneys can be joined in stacks. In lighting the
stove, shavings or straw may be first burnt at the
further end of the hearth, so as to warm the air in
the stove and determine a current. The fuel is piled
up on the hearth close to the door and kindled, and
the current being already directed to the vent, there
is no escape of smoke from the door a3. This door is
now closed and the wicket w opened, by which a
narrow stream or jet of air is directed to the base of
the heaped up fuel, which thus soon enters into brisk
combustion.
It will be evident that in the construction of this
stove the flame and heated products of combustion
are retained as long as possible within the body of the
stove, and the heat diffused over a very extended sur-
face, which is further increased by making the stove
narrower from front to back in its upper part. A
greater breadth is required below on account of the
bulky wood fuel; but if this breadth were main-
tained all the way up, heat would be lost in warming
the partitions 5 but by diminishing the breadth of
these, the proportion of heating surface is increased.
The whole body of the stove is like a long pipe
folded up; and the effect would be increased if each
partition were split into two, and a free passage
allowed between them for the air of the room. To
maintain as large an extent of heated surface as pos-
sible the stove is detached from the wall, and raised
from the floor on short pillars c D, so that both the
back and the bottom of the stove are sources of heat
to the air of the room. In some cases, however, the
stove forms a portion of the wall which separates two
rooms, and serves to warm both; but the door of the
fire is usually in the lobby, so that the servant can
manage the fire without entering the room.
In the best houses, these stoves are described as
being “built in tower-like shapes, story over story of
pure white porcelain, in various graceful architectural
mouldings; sometimes surmounted with classic figures
of great beauty, and opening with brass doors, kept
as bright as if they were of gold. In houses of less
display, these stoves are merely a projection in the
wall, coloured and cornieed in the same style as the
‘ partment. In adjoining rooms they are generally
placed back to back, so that the same fire suffices for
both. These are heated but once in the twenty-four
hours by an old Caliban, whose business during the
winter it is to do little else. Each stove will hold a
heavy armful of billet, which blazes, snaps, and cracks
most merrily; and when the ashes have been care-
fully turned and raked with what is termed an Qferz
gabel, or stove fork, so that no unburnt morsel re—
mains, the chimney aperture is closed over the glow-
ing embers, the brass doors firmly shut, and in about

six hours after this, the stove is at the hottest—in-
deed, it never cools.” 1 There is no doubt that with
this stove there is much heating effect, and great
economy of fuel ; but these results are attained at so
great a cost as the sacrifice of ventilation. Every pre-
caution is taken to prevent the air of the room from
being changed ; the windows are made to fit as tight
as possible, and any cracks or chinks that might admit
a breath of cold air are pasted over with paper;
double windows are common, and doors are made to
close accurately. Hence, the occupants of the rooms
inhale a warm but very corrupt air, which must act
inj uriously on the health.
The stove, Fig. 2M9, although the same in prin-
ciple as the Russian or German, referred to in the
above quotation, belongs rather to the variety known
as the Swedish alone. In the Russian or German
stove, the smoke and products of combustion in
escaping to the chimney, part with their heat to the
sides of the ponderous fine of glazed tiles, built in
several stories in the room which is to be heated. In
the Swedish stove the smoke is exposed to a high
temperature by the heating of the partitions, so that
every particle of soot is consumed. The Swedish
stoves have from 4: to 9 channels for the circulation
of the smoke, and some of the channels are fitted
with ovens, (as in the American stove, Fig. 2248),
others are contrived for the reception of one or more
boilers.
A great variety of stoves with “ascending or de-
scending flues have been contrived at various times:
our limited space will not allow us to do more than
give one or two further examples. Fig. 2250 repre-
sents a section of a stove with
a descending current. The
cover to the stove has an open-
ing at 0 ; f is the fire chamber,
with the grating ; below this,
is a space s, with a second
grating; a, is the ash-pit,
containing a drawer for the
ashes ; F n’ are horizontal
flues on each side of the ash-
box, communicating with ver—
tical flues which lead into
the chimney. The whole arrangement is contained
in a niche formed by closing up the fireplace. In
lighting the fire, the direction of the draught should
be ascertained by holding a flame over the opening 0,
and if it be drawn downwards, the fire is lighted by
first putting charcoal on the grate, placing wood on
the charcoal, and paper on the wood. The paper is
now to be lighted, and the cover to o shut, when air
will pass through the airholes of the cover and cause
the ignition of the materials. The flame and hot air
descending through the grating at f, a current will
pass down, dividing when it reaches s, so as to pass
into the horizontal channels FF’, and from thence
into the vertical fine, and so to the chimney. The
surfaces of the vase and air-box, and those portions of


Fry. 2250.

(1) “ Residence on the Shores of the Baltic.” 1841.
*WARMING AND VENTILATION?
911— ‘
the horizontal channels which are exposed to the
room, are heated by the hot descending currpnt, mi
the air of the room is thus warmed. The success of
this stove depends on maintaining a steady upward
draught in the chimney fine, so that the ash-pit drawer,
and a door in the chamber s, used for removing cinders
&c. from the second grate, must be air tight. In
lighting the fire an upward current may be determined
by holding a flame in a small door in the side of
the flue.
Dr. Arnott’s stove has exciteda good deal of atten-
tion of late years. Its action depends on allowing
the fuel to burn very slowly, the admission of air
being regulated by a peculiar contrivance. Fig. 2251
represents a section of one of these stoves, in which
a box of sheet iron,
at b e (Z, is divided by
the partition y la,
3 ’ into two chambers,
which communicate
freely at the top
and bottom ; e is
the fire-box of iron,
lined with fire-brick,
and resting on a
close ash-pit with a
door at 6, near which
is a valved open-
Fig. 2251. ing, by which air
enters to feed the fire when the door is shut; i is the
door of the stove by which fuel is introduced; a is
the chimney fine. When the ash-pit door and the
stove-door are shut, the quantity of air admitted by
the valved opening in the ash-pit is only just sufiicient
to support combustion, and only a small corresponding
quantity of air can pass away by the chimney. The
whole box then soon becomes filled with hot air, or
smoke from the fire circulating in it, and rendering it
everywhere of as uniform temperature as if it were
full of hot water. This circulation takes place be-
cause the air in the front chamber around the fire-
box, and which receives as a mixture the red—hot air
issuing from the fire, is hotter, and therefore, specifi-
cally lighter, than the air in the posterior chamber,
which receives no direct heat, but is always losing
heat from its sides and back; and thus, as long as
the fire is burning, there must be circulation, the
whole mass of air revolving in the direction of the
arrows. The quantity of new air rising from within
the fuel, and the like quantity escaping by the fine a,
are very small compared to the revolving mass.
With this stove, Dr. Arnott, during the severe
winter of 1836-7, was able to maintain in his library
a uniform temperature of from 60° to 63°. The
coal used must be anthracite, or such as does not pro—
duce smoke in any quantity. Of this coal, six pounds,
or less than a pennyworth, suffice for a day’s consump-
tion. The grate or fire-box, when fully charged, con-
tains a supply for 26 hours.
There are several ingenious contrivances for ad—
mitting the air into this stove, one of which is shown
in Fig. 2252, in which a 6 c is a bent tube closed at a,




(Z


where it contains air, and open at c. The bent part
at 6 contains mercury; from c a bent tube proceeds
and supplies air to the stove. When the internal
heat is great, the air in a expands and forces mer-
cury up in a, so as to close its mouth and prevent air
from entering the stove.
Although the air of the room may be sufficiently
warmed by this stove, yet it soon becomes hot and
oppressive for want of moisture and ventilation. A
pan of water placed on the top of the stove will sup-
ply the one, but as far as respects ventilation this
stove is defective. 11b. of coal requires about 150
cubic feet of air for combustion; but as a portion
escapes without being chemically acted on, 200 cubic
feet may be allowed. Suppose a room warmed by an
Arnott’s stove to I
be 15 feet long,
12 wide, and 11
high, its cubic
contents are
1,980 feet, and if
6 lbs. of coal per
day be burned,
each pound re-
quiring 200 cubic
feet, there will be
only 1,200 cubic
feet used for the
combustion; and
as this quantity must pass through the stove, and be
carried off by the flue, the air of the apartment is not
once changed or renewed by the action of the stove
in the course of 241 hours. This is a sufficient reason
why the apartment is so readily warmed by this stove,
and it also accounts for its unpleasant effects on the
animal system. We fear also that from the slow com~
bustion of the fuel, carbonic oxide is generated, and
that this is liable, from the small draught of the
chimney, to escape into the room.
Coméustz'on of smo/ra—Some of the stoves above
described have the merit of consuming their own
smoke. When much smoke is produced, there is an
enormous waste of fuel, which contaminates the air,
disfigures everything that it touches, fouls the chim~
ney, and sometimes takes fire in the chimney. After
Watt h'ad made the steam-engine an economical source
of power for so many purposes, the rapid increase in
the number of steam-engine and other furnaces led to
a great increase of the smoke nuisance. Watt saw the
evil, and in 1795 took out a patent for a method of con_
structing furnaces so as “to cause the smoke or flame
of the fresh fuel, in its way to the flues or chimney, to
pass together with a current of fresh air, through,
over. or among fuel which has already ceased to
smoke, or which is converted into coke, charcoal, or
cinders, and which is intensely hot; by which means
the smoke and grosser parts of the flame by coming
into close contact with, or by being brought near
unto, the said intensely hot fuel, and by being mixed
with the current of fresh or unburned air, are con-
sumed or converted into heat, or into pure flame, free
from smoke.” There is no doubt that the principle



Fig. 2252.
912
WARMING AND VENTILATION?
thus announced is a correct one, and may be carried
out by any careful stoker without any special con-
struction of furnace. All that is required is to adopt
this precaution: in adding fresh coals they must not
be thrown to the back or middle of the furnace among
the incandescent fuel, for in such case a dense cloud of
black smoke will be produced; but the coals must be
in the first instance carefully placed on a dead plate in
front of the fire, where they may become gradually
heated, in which case the gases which escape from
them are carried in with the draught over the in-
candescent fuel, and undergo combustion; the fuel in
this way becomes coked, and in proportion as it does
so it may be moved forwards towards the centre of
the fire, fresh fuel being added to supply its place
behind. The writer has seen a steam-engine furnace
fed in this way, which emitted little or no smoke from
the chimney shaft; but in order to produce such
a result the stoker must be an intelligent, unpre—
judiced man, and it is difficult to find a poor man
engaged in any pursuit without strong prejudices in
favour of his own way of doing things; and in the
case of stoking, the usual plan is to shovel on the
coals every 20 or 30 minutes as quickly as possible,
throwing them with a vigorous arm to the back of the
furnace. The Stoker then has leisure to smoke his
pipe or to go to sleep until a fresh supply of coals is
wanted. Now the former plan calls for frequent
attention, care, and judgment on the part of the
stoker, which qualities being rare, attempts have been
made to supply them by machinery. One of the best
forms for this purpose is Juaire's patenéfamace. The
following is a description of one in actual use in
Truman’s brewery, which we prefer to a general de-
scription on account of the statement of the actual
saving of fuel which accompanies it. J ucke’s furnace
“ consists of a strong cast‘iron frame of the full width
of the furnace, and about 3 feet longer. The fire-bars
are all connected together, forming, when complete,
an endless chain, and are made to revolve round
a drum, placed at each end of the frame. The front
of the frame is provided with a hopper, in which the
fuel is placed, and a furnace-door, which opens verti-
cally, with a worm and pinion. The height to which
this door is raised by the stoker regulates the supply
of coal, which is carried into the fire by the ‘gradual
motion of the bars. The whole machine is placed
upon wheels, to facilitate its removal for repairs to
the boiler, brick-work, or furnace. The speed of the
furnace-bars is determined by the draught. It varies
from 1% inch to 3 inches per minute, the object being
to keep the whole of the bars covered with fuel, with
a small accumulation of fire at the bridge. The
bridge is suspended by a pipe, 3 or a inches in dia-
meter, fixed about 1 inch above the level of the bars;
this allows the clinkers formed to fall into the ash~pit,
but will not allow the fire to pass. A small stream of
water must be supplied to the pipe or stop, or itswill
soon be destroyed. All the air admitted to the fire to
support combustion is made to pass through the fur-
nace-bars.” Messrs. Truman first applied this appara-
tus to a-cylindrical engine-boiler with 2 tubes, driving

a 410-horse engine, and it was afterwards applied to a
brewing copper. “ But with a brewing copper provi—
sion has to be made for a process in the manufacture
almost peculiar to it: the contents of the copper have
to beturned out several times in the course of a brewing,
rendering it necessary to ‘ bank-up ’ the fire thoroughly
to protect the bottom of the copper until refilled with
wort or water. It was feared that the machinery
would interfere with this being done effectually: it
was tried, and with the same success as with the
steam-boilers. It was found that a fire of 50 or 60
feet area could be worked for any number of hours
without the slightest appearance of smoke from the
chimney shaft; but the process of banking-up required
the whole principle of the machine to be put in abey-
ance, during which time smoke escapes from the
shaft, sometimes in large quantities, and no plan has
been discovered for its prevention.” The apparatus
was applied to 141 furnaces, at a cost, including brick-
work, of about 3,0001. The consumption of coals in
the brewery is about 6,000 tons per annum. The
saving in the coal account since the introduction of
the patent furnaces has been as follows :—

56 s. d.
July 1,1848 69 4 0
,, 1849 631 4 0
,, 1850 1,606 0 0
,, 1851 1,92512 0
,, 1852 1,906 0 0
.n 1853 2,200 0 0
£8,338 0 o
from which sum is to be deducted for casualties and
sundries about 3501. “The above: economy has not
arisen from less weight of fuel consumed, but owing
to the screenings or dust of coal only being required
for the furnaces.” 1 Mr. George Wilson has used
three forms of apparatus, patented by Jucke, Hazel-
dine, and Hall, respectively. They act on the same
principle: “ a very small continuous supply of fuel at
the front of the grate, the smoke always being made
in small quantities, combines with the air that passes
through the bars, and is burnt before it can escape.
All three have the advantage that there is no opening
of fire-doors, and therefore an avoidance of the rush of
cold air, which must have an injurious effect by con
tracting the boiler-plates, in addition to the loss of
heat. The only comparison we have to give of smoke-
consumers with old-fashioned furnaces, is, that our
smoke-consumers do as much work with small coal as
the old furnaces did with large. We tried a smoke-
consumer, firing and stoking as in common furnaces,
and found the coal used to be 12 per cent. more than
when the grate was used as a smoke-consumer.”
Accepting the common definition of smoke as un-
consumed fuel in a state of minute division, or that

(1) The above details are from a paper by Mr. A. Fraser, “ On
the Consumption of Smoke,” read before the Society of Arts,
London, 30th November, 1853, and printed in the Society’s'
Journal, No. 54, together with a notice of the discussion which
took place thereon. In No. 57 is an account of a further discus-
sion on the subject. In vol. i. of the Society’s Journal, p. 626,
is an interesting letter from Mr. George Wilson, recording his
experience with smoke-consuming apparatus at Price’s factory at
Belmont and at Batter-sea.
WARMING AND VENTILATION.
913
“smoke consists essentially of carbon, separated by
heat from coal or other substances, and is commonly
mixed with carbonic acid gas, carbonic oxide, and
other matters,” we may just glance at the principle of
the various other contrivances that have been in-
vented to get rid of it. It is, however, preferred in
many furnaces to use coke or anthracite, so as not to
produce any smoke. But where bituminous coal is
used, the compounds of carbon and hydrogen, which
are distilled off by the heat, do not undergo combus-
tion, on account of the deficient supply of air to the
furnace; there may be sufficient heat to decompose
them, and thus increase the quantity of minutely
divided carbon or visible smoke; but for want of
oxygen they escape with the draught into the chim-
ney, and so are discharged into the air. Hence, if an
additional quantity of air be thrown into the fire so
as to produce perfect combustion of the carbonaceous
matter, not only would more heat be produced from
a given quantity of fuel, but no smoke would escape.
Many plans have been contrived for admitting air to
the fuel; in some cases it was warmed before it came
in contact with the hot vapours; in others it was ad-
mitted in the form of numerous jets; others, again, al-
lowed it to pass in at the ordinary temperature through
sliding doors and regulators, in which case the con_
sumption of fuel was increased. Another plan was
to supply the fire with fuel in small quantities, “ much
scattered and divided, so that the coal was not only
ignited as it fell upon the fire, but the heated vapours
at the same time had a supply of air sufficient to pro-
duce their complete combustion. To some extent
this might be effected by the careful stoking of a skil-
ful fireman in a well-constructed furnace : but as
this constant attention to the supply and frequent
stoking of the burning coals involved often’ repeated
openings of the fire-doors, and the consequent admis-
sion of cold air in excess, mechanical contrivances had
been introduced which, without opening the fire-doors
(until it became necessary to raise the fire from the
grate-bars, and to clear them from the elm/ters, or
earthy parts of the coal vitrified by the heat), scat-
tered a constant and continuous supply of fuel upon
the fire. In most of these devices there was a hopper
filled with coal, and a pair of rollers through which it
passed. It then either fell directly on the fire, as in
Brunton’s revolving grate, or it was scattered over
the fire by the centrifrugal action of fans or wings
fixed upon the surface of two very flat cones, upon
which the coal dropped from the rollers, as in Mr.
Stanley’s plan, much used in Manchester, where the
governor of the steam-engine regulated also the supply
of fuel to the furnace, according the engine’s demand
for steam.” 1 The necessity for raising the fire to re-

(1) From Mr. Glynn’s address to the Society of Arts at the
adjourned discussion on the consumption of smoke. We may
also refer to the Report of the Parliamentary Committee of the
years 1819 and 1820, “ to inquire how far it may be practicable to
compel persons using steam-engines and furnaces in their dif-
ferent works, to erect them in a manner less prejudicial to public
health and public comfort.” This Report contains a large num-
ber of plans for preventing or consuming smoke, the principles
of which are given above, and some of them must have impressed

move the clinkers is an objection to this plan, and led
to that of giving “ a longitudinal motion to the grate,
by which it fed itself with coal at the furnace mouth,
and cast off the clinkers at the tail-end of the fire-
bars, the forward motion corresponding with the con-
sumption of the fuel; while by other motions given
to the fire-bars the mass of fire was broken or stoked
so as to admit a due supply of air, and the clinkers
disengaged from the bars, so as to be readily cast off
when they reached the end of the bars.” Mr. Jucke’s
arrangement on this principle has been already noticed.
Hall’s arrangement consists of a series of bars of the
whole length of the fire. moved alternately by an
eccentric shaft in front: the motion is very slow, but
the effect is to supply the fire with fuel from a hopper
in front. In Hazeldine’s arrangement the bars are
of the width of the fire, transversely with the boiler;
a peculiar motion is given by a cam to each bar, by
which the fire is supplied with fuel from a hopper,
which is opened vertically by a rack and pinion. Mr.
Glynn also mentioned a plan by Mr. Godson for sup-
plying furnaces “with coal from below by forcing up
a column of fuel, which was lighted at the top, and
caked as it was delivered to the furnace, the column
of coals being pressed upwards in a box as a candle
was raised in the socket of a candlestick, or like the
wick of a lamp.”
The preceding plans refer to furnace-fires. Not
many plans have been proposed for consuming the
smoke, and preventing the formation of soot in do-
mestic fires. Dr. Franklin, however, contrived the
circular fire—cage, Fig. 2253, which is about a foot in
diameter, and from 6 to 8
inches wide from front to
back: the back is of
plate—iron, and the front
contains bars, of which
the 3 middle ones are
fixed, and the top and
bottom bars movable, so
that either may be drawn
out for the purpose of
filling the grate with
fuel. J The cage turns
upon axes, supported by a crotchet fixed on a stem
which revolves on a pivot fixed to the hearth. The
fire is lighted by withdrawing the upper bar, and
placing paper, wood, and coals in the grate: the bar
is then replaced. When the fire is first lighted,
smoke is produced; but as soon as the fire begins to



Fig. 2253.
the Committee with their efliciency, (as indeed they are efficient
if properly carried out,) for they state in their Report that a
means of destroying smoke “had been satisfactorily and effec-
tually obtained.” The abundance of fuel and the absence of
skilled labour in its application. have caused the whole subject to
be nearly forgotten, although a second Parliamentary (Zommittee
heard evidence and reported thereon in 1843; and it was not until
the session of 1853, when an Act was passed, requiring manufac-
turers and others using furnaces to consume their smoke, that
means are now being adopted for carrying into effect a process
which was successfully applied by Franklin and Watt in the last
century, and has been presented to the public in the middle of the
present century, with much of the inexperience which accom-
panies new and untried schemes.
3N
9141
WARMING AND VENFILATIQN.~
burn well the cage is turned round on its axes, so that
the incandescent coals at the bottom shall be upper-
most; the whole is then turned round 011 the pivot,
so as to bring the bars again in front, by which
arrangement the fresh coals will be below the ignited
fuel, and these gradually kindling, their smoke will
pass through the fire above them and be consumed.
011 adding fresh fuel the top bar is removed, then re-
placed, and the cage turned over and round as before.
The cage can of course be turned round upon its
vertical axis, so as to radiate its heat in any direction,
and by placing the bars in a horizonal position a
kettle may be boiled on them.
In Section III, a warming, and ventilating, and
smoke consuming stove will be described.
3. 1716 cockle stoned—This is a contrivance for heating
, 0 a large body of air.
\\\\\\s\\\\\\\




2254, is cylindrical
in form, with a
flat or dome-shaped
head, and a pipe
leads from near the
upper part to carry
off the smoke into
the flue. The cockle
is placed on a bed
of masonry or brick-
work, with a grat-
ing Z? for the fire,
and an ash-pit a, beneath, as in Figs. 225a, 2255.
The fuel is supplied at the doorf, and passes down a
sloping dead-plate p to the grate. The ash-pit and
draught~hole are shown at a. Surrounding the cockle
at a certain distance, and concentric therewith, is a
mass of brick-work 66 forming a space for the air,
which is to be heated, and which is supplied from
the passages below or from the external air. The
I The COekle or fire-
\\ Chamber, 6’




\
Fig. 225%.

__..._
t








a It: _ I ' ‘a ll lltrlttttart. I’ it“?



Fig. 2255.
air thus brought into contact with the hot surface
of the cockle becomes heated, rarefied, and ascends

(I) Also called the Edgar stove, in honour of Mr. Strutt, of .5’
Belper, in Derbyshire, who first-introduced the cockle.
n
P
and passes out through one or more apertures 0
into the room which is to be warmed. The cockle
may be varied in form so as to present a larger
heated surface to the air. Fig. 2255 shows the
arrangement of this stove in the Derby Infirmary.
The stove should be erected as near the area of the
building as may be convenient, and be situated from
6 to 12 feet below the floor, to make the distribution
of warm air tolerably uniform. The cockle c, Fig.
2255, is cubical in form, with a domed or groined
arch top; it is about 3 feet in diameter and 4: feet
high, and is made of iron plates riveted togei her.
The smoke passes off by a narrow passage at the base
of the cockle through the flue j: The brickwork
surrounding the cockle is built with alternate open—
ings between the bricks, at about 8 inches distant
from the sides of the cockle, and in these apertures are
placed pipes of sheet iron, or common glazed ware,
passing to within an inch of the cockle, by which .
means the air to be heated may be thrown near, or in
immediate contact, with the surface of the cockle, if
desirable. The horizontal partition in cuts off the
communication between the lower and the upper por-
tion of the air-chamber, the arched openings in the
lower half being the openings of the main air-flue
leading from the exterior atmosphere. The fire-room
and ash-pit are at a, and the fuel is introduced by
the opening at 0. In this arrangement, the air pass—
ing from the lower arched flues, through the apertures
beneath the horizontal partition, comes into imme-
diate contact with the surface of the cockle, and finds
its way into the upper air chamber, AA, through the
numerous pipes or openings of the upper division, by
which circuit its velocity is sufficiently retarded to
acquire the necessary elevation of temperature from
the heated cockle. To prevent the air from being
burnt, the size of the fire-chamber must be regulated
so as not to raise the cockle to a higher average tem-
perature than 300°. The Derby stove allows the
passage of nearly 5 cubic feet of air per second, vi hich
is raised to about 130°, when it escapes from the
upper air-chamber into the pipes leading to different
parts of the building. These pipes are furnished with
dampers to regulate the admission of the warm air.
If care be taken to prevent the air from being burned,
this method of heating a large building has its advan-
tages. It would scarcely answer on a small scale, on
account of the expense of erection; nor could it be
well applied to a large building, unless constructed
during the erection of the edifice. The air passages
being placed several feet below the surface of the
ground, allow a portion of cold air to be admitted to
the interior of the building during summer, by means
of a revolving mouth-piece, or turn~cup, placed at the
opening of the air-passage, so as to receive the current
of wind at the outer extremity of the passage, and
thus convey it to the interior.
4:. By Steam—The first application of steam to the
warming of rooms, that we are acquainted with, was
made by James Watt in 17 S41, who contrived an
apparatus for warming his study, the dimensions of
which were 18 feet in length, 1a in width, and 8 5 in
.WABMING AND _VENTILATION.
915
height. The apparatus consisted of a box or heater
made of 2 side plates of tinned iron ‘about 3%; feet
long by 2,1,- wide, kept asunder about an inch by
means of stays, and closed at the edges by tin strips.
This heater was placed on edge near the floor. It
was furnished with a cock for letting out the air, and
was supplied with steam from a boiler by a pipe en-
tering its lower edge, by which pipe the condensed
water returned to the boiler. The steam on being
admitted into the box was condensed, and the latent
heat of the steam being liberated heated the box,
which in its turn radiated heat into the apartment.
The experiment, however, does not seem to have been
very successful.
Mr. Hoyle, of Halifax, in 17 91, patented a method
of heating by means of steam pipes. The steam was
conveyed by a pipe from the boiler to the highest
point which was required to be heated, from which by
a gentle declivity the condensed water flowed into
the supply cistern of the boiler. The pipes were of
copper, and too small to produce much useful effect,
and so the plan was pronounced a failure.
In 17 99, Mr. Lee, of Manchester, erected a heat-
ing apparatus of cast-iron pipes, which also served as
supports to the floor. This apparatus was constructed
by Boulton and Watt, and is said to have been suc-
cessful.
It is not economical to warm by this method unless
there is a steam-engine on the establishment in daily
use for other purposes. The steam pipes may then
be supplied from the engine boiler, the dimensions of
which may be enlarged at the rate of one cubic foot
for every 2,000 cubic feet of space, to be heated to
the temperature of 70° or 80°. A boiler adapted to
an engine of one-horse power, is suflicient for warm-
ing 50,000 cubic feet of space. Hence an apparatus
erected for the purpose is not required to be of very
large size, nor is the quantity of fuel consumed great.
It is stated that if the fire under a small boiler be
carefully managed, 14 lbs. of Newcastle coal will con-
vert one cubic foot of water at 50°, into 1,800 cubic
feet of steam at 216°; and only 12lbs. of coal are
required to convert the same quantity of water into
steam at 212°. The shape of the boiler, and the
method of setting it, are of importance, and the
furnace must be arranged so as to admit no more air
than is required to support the combustion. The hot
air must also be kept in contact with the sides of the
boiler, until as much of the heat as possible be ab-
stracted from it. In such an arrangement, according
to Dr. Arnott,1 nearly half of all the heat produced
in the combustion is applied to use.
The expenditure of the heat produced is, 1. Through
the thin glass of the windows; 2. More slowly
through the walls, floors, and ceiling; and 3. In com-
bination with the air which escapes at the joinings of
the windows and doors, or through openings expressly
made for the purpose of ventilation. The amount of
heat lost in this way has been variously estimated by

(I) “ Warming and Ventilation, with directions for making the
Thermometer Stove, &c.” London, 1838.

Tredgold and other writers, but Dr. Arnott states it
thus :——That in a winter day, with the external tempera-
ture at 10° below freezing, to maintain in an ordinary
apartment the ‘agreeable and healthful temperature of
60°, there must be of surface of steam pipe, or other
steam vessel heated to 200° (which is the average
surface-temperature of vessels filled with steam of
212°), about 1 foot square for every 6 feet of
single glass window of usual thickness; as much for
every 120 feet of wall, roof, and ceiling of ordinary
material and thickness; and as much for every 6
cubic feet of hot air escaping per minute as ventila-
tion, and replaced by cold air. A window, with the
usual accuracy of fitting, allows about 8 feet of
air to pass by it in a minute ; and there should be for
ventilation, at least 3 feet of air per minute for
each person in the room. According to this view,
the quantity of steam pipe or vessel required under
the temperature supposed, for a room 16 feet square
by 12 feet high, with two windows, each 7 feet by 3,
and with ventilation, by them or otherwise, at the
rate of 16 cubic feet per minute, would be—
Feet.
For 42 square feet of glass (requiringl foot for 6) 7
,, 1,238 feet of wall floor and ceiling (requiring
1 120)‘.‘Ill‘.IIIIIIOIUIOOIIII IUIUOIIIO III a ,, 16 feet per minute for ventilation (requiringl
foot for 2:

Total of heating surface required............ 20
Which is 20 feet of pipe, 4+. inches in diameter, or any
other vessel having the same extent of surface, as a
box 2 feet high, with square top and bottom of
about 18 inches. It may be noticed, that
nearly the same quantity of heated surface would
suffice for a larger room, provided the quantity of
window glass, and of the ventilation, were not
greater; for the extent of wall, owing to its
slow conducting quality, produces comparatively
little effect.
Dr. Arnott also states that a heated surface, as of
iron, glass, &c., at temperatures likely to be met with
in rooms, if exposed to colder air, gives out heat with
rapidity, nearly proportioned to the excess of its
temperature above that of the air around it, less than
half the heat being given out by radiation, and more
than half by contact of the air. Thus, if the external
surface of an iron pipe, heated by steam, be 200°,
while the air of the room to be warmed by it is at
50°, showing an excess of temperature in the pipe of
14¢O°, such pipe will give out nearly 7' times as
much heat in a minute as when its temperature falls
to 80°, because the excess is reduced to 20°, or 73;" of
what it was. Supposing window glass to cool at the
same rate as iron plate, one foot of the steam pipe
would give out as much heat as would be dissipated
from the room into the external air by about 5 feet
of window, the outer surface of which was 30°
warmer than that air. But as glass both conducts
and radiates heat about -;-th slower than iron, the exter—
nal surface of the glass of a window of a room, heated
to 60°, would, in an atmosphere of 22°, be under 50°,
leaving an excess of less than 30°; and about 6 feet
3 n 2
‘916
WARMING AND VENTILATION.
of glass would be required to dissipate the heat given
off by 1 foot of the steam pipe. In double win—
dows, whether of 2 sashes, or of double panes, only
half an inch apart in the same sash, the loss of heat
is only about 5th of what it is through a single
window. It is also known that 1 foot of black or
brown iron surface, the iron being of moderate thick-
ness, with 11l0° excess of temperature, cools in 1
second of time 156 cubic inches of water, 1 degree.
From this standard fact, and the law above given, a
rough calculation may be made for any other com-
bination of time, surface, excess, and quantity. And
it is to be recollected, that the quantity of heat which
changes, in any degree, the temperature of a cubic
foot of water, produces the same change on 2,350
cubic feet of atmospheric air.
An apparatus represented in Fig. 2256, for warming
air by means of steam, has recently been introduced
by Messrs. Hamilton and Weems. By means of a fan
I‘, usually situated on the outside of the building, pure
air is driven through and between a series of concen-



Fz'g. 2256. _
tric annular steam chests c c, and is 'emitted in a
warm state by a pipe r. The steam chests receive
steam from the boiler, or in high-pressure engines from
its exhaust pipe, which is fitted for the purpose with
safety and collapse valves vv', to regulate the pressure,
and a stop-cock to regulate the supply. The con-
densed steam is carried off by a pipe into a cistern K,
and thence back to the boilers. The warmed air can
be supplied with moisture by allowing a regulated
quantity of steam to mix with it in passing through
the apparatus.
5. By leer‘ Warren—The method of heating by steam
pipes has long given way to hot water apparatus.
Of this there are two distinct modifications depend-
ing on the temperature of the water, and known
as the low pressure and the lzz'g/e pressure systems.
In the one case the water is at or below the or—
dinary temperature of boiling. In the other it is
heated to 350° and upwards, so that its tendency is to
burst into steam with a pressure of '70 lbs. and up-
wards on the square inch, and hence it requires to be
confined by very strong or high pressure apparatus.
In the low pressure system the pipes do not rise to
any considerable height above the level of the boiler,
so that the apparatus does not require to be of extra-'
‘ordinary strength, either on account of hydrostatic
pressure or of temperature. One pipe rises from the
.top of the boiler, traverses the rooms which are to be
warmed, and returns to the boiler, which it enters
near the bottom. The pipes heated by the water
‘radiate their heat into the rooms, and the water being
cooled in the process has an increasing tendency

to descend, just as the tendency of the water in the
boiler is to ascend. If the apparatus be properly
arranged a constant circulation will thus be main-
tained through the whole system of pipes, so long as
there is a spark of fire under the boiler; and, indeed,
so long as there is any marked difi’erence in tem-
perature between one part of the apparatus and
another.
The first application, on a large scale, of hot water
as a source of heat was made in France, in 177 '7, by
M. Bonnemain, in an apparatus for hatching chickens.
This apparatus consisted of a boiler b, Fig. 2257, a
feed-pipe f; and a
pipe it, (regulated
by a stop-cock
0) by which the
hot water ascends
from the boiler
into the heating
pipes. These tra-
verse the chambers Fie- 2257-
which are to be heated, and are fixed with a gradual
slope towards the boiler, to which the water is con-
veyed by a pipe r, which passes nearly to the bottom of
the boiler, the velocity of the current depending on
the difference between the temperature of the water
in the boiler and that in the descending pipe. At the
highest point of the apparatus is a pipe a, regulated by
a stop—cock, for allowing the escape of the air con—
tained in the cold water which is supplied to the
boiler, and which becomes liberated by the heat. On
opening the stop-cock, there‘ may be a rush of water
as well as of air, and a small cistern, 0, is provided
for its reception.
The low pressure system has of late years been
greatly improved and largely introduced in conse—
quence of the scienti-
fie exertions of Mr.
Hood.1 Fig. 2258 re-
presents an arrange-
ment on his system
for warming 3 or 4B
floors. In such a case
as this, the vertical
pipe from the boiler
may be carried up to
the highest story, and
the return pipe be
made to diverge into
each story on its way
to the boiler. In such
an arrangement, the
top story will be
most heated, and the


5§§
l



Fig. 2258.
heat will. gradually diminish in the lower stories, as
water cools in descending. A better arrangement is
to supply each story with a separate range of pipes
branching out from the main pipe, and returning

( 1) The reader who desires to be fully acquainted with the sub-
ject of which it treats, will do well to study Mr. Hood’s instructive
volume, “Practical Treatise on the Warming of Buildings by
hot Water,” 850. Second Edition, 1844.
WARMING AND VENTILATION.
917
together or separately to the boiler. If, however,
the branch pipes be simply inserted into the side
of the vertical ascending pipe, ‘,there is danger of
the hot current passing by instead of flowing into
them. The motion of the upward current requires to
be checked in some way, and this may be done by ar-
ranging the pipes as at b or c, Fig. 2258, at which
points it is evident that the water in ascending from
the boiler B, receives such an amount of retardation,
as to cause it to flow along the horizontal pipe at that
level. If it be required to cut off the supply of heat
from any one story, all that is necessary is to close
the stop- cocks s t, in any one horizontal branch, and
the hot current will not pass along it.
In some arrangements, a vertical main discharges
the hot water into an open cistern at the top of the
building, and from this cistern the water is distributed
by pipes to various parts of the building. By driving
a plug into one of the flow pipes at the bottom of the
cistern, any required portion of the building can be
cut off from the heating efi'ect.
Of course the boiler must be made sufficiently
strong to resist the hydrostatic pressure of the water.
A tube of the sectional area of 1 inch, rising from the
boiler to the height of 34s,’; feet, both tube and boiler
being full of water, will exert a bursting pressure on
every square inch of the inner surface of the boiler of
about 15 lbs. By increasing the sectional area of the
tube, the pressure is not increased, but only distri-
buted over a larger surface of the vessel. A boiler,
3 feet long, 2 feet wide‘, and 2 feet deep, with a pipe
28 feet high proceeding from the top, will sustain a
pressure of 66,816 lbs, or nearly 30 tons. A wrought-
iron saddle-shaped boiler, such as that shown in Fig.
2258, is a good form. The size will of course depend
on the extent of pipe to be served; but as a general
rule, 1 square foot of boiler should be allowed to
50 feet of 4~inch pipe, the temperature of which is to
be maintained 140° above the surrounding air. If
the temperature be 120°, the same boiler surface will
heat one-sixth more pipe; if 100°, one-third more.
Soft or rain~water should be used in the hot water
apparatus in order that no sedimentary crust may be
formed.
With respect to the size of the pipes, a diameter ‘of
41in0hes is the largest that should be used, and these
are well adapted for heating hot—houses and conserva-
tories. Pipes of 2 or 3 inches may be used for warm-
ing churches, factories, and dwelling-houses. The
quantity of pipe required is estimated by Mr. Hood
in the following manner :——Allowing 3%; cubic feet of
air for each person in the room, or hall, &e., as the
quantity per minute which is to be warmed, and 1
cubic foot per minute, as the quantity cooled by each
square foot of window glass ; and in hot-houses, 830.,
allowing 1;}; cubic foot of air per minute as the quan-
tity to be warmed for each square foot of glass; then
ascertain the whole quantity of air which is to be
heated, and apply the following rule :—“ Multiply 125
(the excess of temperature of the pipe above that of
the surrounding air) by the difierence between the
temperature at which the room is purposed to be kept

Iwhen at its maximum, and the temperature of the ex-
ternal air; and divide this product by the difference
between the temperature of the pipes and the pro-
posed temperature of the room; then, the quotient
thus obtained, when multiplied by the number of
cubic feet of air to be warmed per minute, and this
product divided by 222 (the number of cubic feet of
air raised 1° per minute by one foot of ét-inch pipe),
will give the number of feet in length of pipe its—11101168
diameter, which will produce the desired effect.” For
3-inch pipes, multiply by 1'33 the number of feet of
41-inch pipe obtained by the above rule 3 and for 2-inch
pipe multiply this quantity by 2.
The size of the pipe selected must, of course, depend
on the circumstances of the case. If the heat is to be
maintained after the fire has gone out, large pipes
should be used ; but if the heat is not wanted after
the fire is extinguished, small ones will be best. It
is not desirable to make the main pipe of larger
diameter than the branches, unless these extend to
a considerable distance. If an 8-inch main supply
4. branches, and this main be reduced to 4b inches,
the water must travel 4! times faster through the
smaller pipe to perform the same amount of work,
and in such case the water will lose only half as much
heat in passing through the small main, as it would
do in ascending the larger one. Hence a small main
may have advantages over a large one; for it is
desirable to economise the heat, until it gets to the
point from which it begins to be distributed.
It is surprising how small a force is required to
generate a current in the hot-water apparatus. It is
merely the diEerence between the temperatures of the
water in the boiler, and that inthe pipes; and even
from this force large deductions must be made for
friction. If the temperature of the water in the
descending pipe be 170°, and that in a boiler 12
inches high, 178°, the difference in Weight is 8'16
grains on each square inch of the section of the return
pipe. In an example given by Mr. Hood, the boiler
is 2 feet high 5 the distance from the top of the upper
pipe (which proceeds in a horizontal direction from
the top of the boiler) to the centre of the lower pipe,
18 inches, and the pipe 41 inches in diameter; the
difference of pressure on the return pipe will be 153
grains, or about ;1; ounce, and this will be the motive
power of the apparatus, whatever length of pipe be
attached to it. With a boiler containing 30 gallons
of water, 'and 100 yards of 4-inch pipe, there will
be 190 gallons, or 1,900 lbs. weight of water kept
in continual motion by a force equal to only one-
third of an ounce! So feeble a force is liable to be
overcome, unless care be taken in the arrangement
and fixing of the pipes. The pipes must be so dis-
posed that the water in its descent be not obstructed
by differences of level, or angles where air may accu-
mulate; for, if the stream be divided by a bubble
of air, the circulation is arrested. Whenever an
alteration in level occurs, an air-vent must be
provided.
We now proceed to notice the high-pressure appa-
ratus which was contrived by Mr. Perkins. In its
918
WARMING AND VENTILATION.
simplest form, this apparatus consists of a continuous
pipe of wrought-iron, 1 inch in external, and @— inch
in internal diameter,
3, 2 filled with water, a por—
.7i_ tion of the pipe, about
“It 71th of the whole length,
being coiled up in the
~ i furnace, and supplying
i the place of a boiler.
S c c _ S The coil re, Fig. 2259,
3 being entirely sur-


la
'9'
l
rounded by the fire, the
water heats rapidly ;
and, becoming charged
with minute bubbles of
steam, a rapidly ascend-
ing current is formed.
@—
4—'-



8‘ t»
S“ 3*‘ ‘fit: S At the upper part of
g; ' the pipe, ‘the steam
“a condenses into water,
which unites with the
t t column in the return
* pipes (; c. The descent
is rapid, in proportion
to the expansion of the
water in the ascending
column; the rapidity
of the current being in proportion to the relative
specific gravity of the two columns. The expansion
of the water by heat is allowed for by connecting a
pipe E, 2;}- inches in diameter, with the highest point
of the. apparatus. The filling pipe is inserted at the
lower part of the expansion pipe. In filling the appa~
ratus, the expansion pipe is left open at top; air is
expelled from the pipes by pumping water repeatedly
through them ;1 and, when the apparatus is properly
filled, the filling'pipef and the expansion tube E are
closed with screw plugs 19. The expansion pipe is not,
of course, fillediwith water; and, in general, from 15 to
20 per cent. of expansion space is allowed. The fur-
nace is generally so placed as to allow the tube from the
top of the coil to be carried in a direct line a. to the


Fig. 2259.


m


........ ..
ail‘
\\illlll‘“
llllll
'- "\\\" .s-k:
llhl- 6
' "I I I ‘,~\\~
“\\\-
~///I.‘I.'i IH
Ill ’2-'-*
Fig. 2260.
highest point; and from this 2 or more descending
columns a a can be formed, and be made to circulate

through different parts of the building, uniting into one
pipe just before entering the bottom of the coil in the
furnace. The pipe is also formed into coils s s in diffe-
rent parts of the building, each coil being placed within
a pedestal, surrounded by trellis-work; or the coil may
be sunk into the floor when of stone, or placed behind
a skirting, or in the fireplaces of each floor, the fines
being stopped. A common form of furnace for heat—
ing the coil is shown in Fig. 2260. It varies from 31, to
6 feet square, according to the extent of pipe. The
fire occupies a small space in the centre, raised about
a foot from the ground, and the fuel is supplied through
the hopper door (Z. The outer casing c is of common
brick-work; Z l are Welsh fire-lumps ; , f f are fire-
bricks, supporting the coil k; M‘, reservoirs for the
dust and soot, which would otherwise clog the coil 5
[2, bearing bars for the grate 5 g, the grate: the fire-
door is double, and there are also doors to the ash pit
and dust reservoirs. Fig. 2201 shows the descending
tube entering the fire-chamber, and passing through
i,
Fig. 2:61.



the bearing bars 6 b, of the grate 51. Fig. 2262 is a
section of the back well or reservoir r9‘, formed so as
to support the coil, and to cause the soot and dust to
fall to the bottom.
In this arrangement, the ignited coal is surrounded
on three sides by a thickness of 9-inch fire-brick, or
Welsh lumps ; the hopper door is also placed in one
of these lumps; the coil is contained in a chamber
round the fire—brick, 4% inches wide; the pipe enters
this chamber, passing through the bearing bars of the
grate, which tends to preserve the grate from burn-
ing; the pipe passes out from the top of the coil, at
the upper part of the chamber. The smoke passes
through the chamber containing the pipes, and escapes
through an opening at the back. The coil is in actua
contact with the fire only in front. The best fuel for
this furnace is coke or anthracite. The furnace may
be placed in a cellar, or be completely removed from
the building. The heat of the furnace can be mode-
rated by closing the ashpit door, and opening the f ur-
nace door, or the reservoir doors, so as to lessen the
draught, and admit cold air to the coil.1
6. Warming and coo/ring 6y gala—The general in-
troduction of gas into private houses has led to various
contrivances for warming rooms and cooking food by
its means. The open fire is so much associated with the
ideas of domestic comfort in this country, that attempts
have been made to combine the economy and cleanli-

(1) “ The high-pressure system is expounded in Mr._Richard-
son’s “Treatise on the Warming and Ventilation of Buildings,”
&c., second edition, 1839. Mr. Hood’s work shows the relative
merits of the three methods of warming, viz. by steam, and by low
and high pressure water apparatus.
W'ARMING AND VENTILATION;
919‘
ness of gas with that condition in a arming apartments.
Mr. Goddard, engineer of the Ipswich Gas Works, has
contrived a stove in which asbestos is used for giving
visibility to the fire. This stove has the further
advantage of being portable; the‘ sides fold down so
as to form a box of moderate dimensions. Fig. 2263
represents it open, with the flattened coil-burner ready
-.--s






niuuii -
‘ L lllllllhhlllltllllilllliitltlii
' _ “mumniiuiunuiiimwr
-_\ l‘l 'llllllilllll'll lllllh


HIE
l'l




‘ -
av-qw' -
@ pull ~
I!‘ >~ an ,
g llllllll __





u‘.- Y-‘r‘tH-r. \_
' /
-~ ’=§_\?Zisiw -
K"


i~"k‘o'1l"'~ U'B'. Eli ‘hr hi" .-
- :4


Fig. 2264.
for use. Fig. 2264: shows the stove not intended to
collapse or shut up ; here the effect of'the burning
fire is shown. The fire-chamber is coated internally
with porcelain, and within this the tubular burner is
set at an angle of 45°. A quantity of asbestos shav-
ings is first spread over this burner, and the gas being
turned on and ignited, the effect is something like that
of a common fire. The porous nature of the asbestos
admits an abundant supply of air, so that the gas is
consumed without the production of smoke. A con-
sumption of about 7 cubic feet of gas per hour, at a
cost of about 1M. for 12 hours, is sufficient to heat a
good-sized room. The asbestos, which is indestruc~
tible, costs about 2d.
Wm'rl’s gas stove consists of a plate of thin sheet-
iron, which is fitted into an ordinary fireplace after
the manner of a fire-board, about 2 inches within the
projection of the mantel-piece ; about 3 inches in front
of the back plate, a similar plate of sheet iron is
fastened by bolts; a third plate, somewhat smaller, is
placed about 1 inch from the second plate and enclosed
at the top, bottom, and sides, so as to form a chamber
2 or 3 feet square, and 1 inch in thickness. Towards

the bottom of the last plate ‘is cut a long aperture,
closed by a sliding plate which acts as a door, for
lighting the jets of gas and admitting a small quantity
of air. A little below the aperture is introduced a
pipe in which 3 or more gas jets are fixed, arranged
so that the flames may extend laterally and not touch
the iron. From the top of the enclosed chamber, a
pipe 11,; inch in diameter proceeds through the second
and first plates into the chimney. The inventor states
that this apparatus will raise the temperature of an
ordinary-sized room 5° or 10° with a consumption of
about 3 cubic feet of gas per hour, or at the cost of
241. for 10 hours. The stove by its vertical position
exposes a considerable surface for the absorption of
heat from the gas, and for the radiation of heat, and
it projects only 2 or 3 inches into the room.
Mr. Graham, of the Eagle Hotel, Glasgow, has con-
trived a gas cooking-stove, shown in sectional elevation
Fig. 2265, and in plan Fin‘. 2266. The two end plates








E1 WW1”)?
n ~12 1' |
ll ‘
u
‘r

















ii‘llllllllllllllliitllllllllilli



Fig. 2265. GAS COOKING-STOVE.


p ' Fig. 2266. PLAN.
I I are of iron, with a back plate of the length of the
range, and a top plate: the front is furnished with 3
doors. The gas is conducted from the main by a pipe
G, from which 7 branches spread to corresponding
burners inside and on the top of the range. The
5 branches 1, 2, 3, a, 5 lead to 3 different sizes of burner
scrolls intended for boiling or heating vessels placed
on the top of the range. Each pipe passes close over
the top of the range, and the terminal volute rests
on the surface. It is studded throughout with small
gas burners, and is surrounded by a ring of studs 3 s
rising from the top of the range. These studs stand
up somewhat higher than the burners, and are con-
nected together by a flat metal ring R, which retains
the heat from the burners and guards them vfrom
920
WARMING AND VENTILATION.
contact with atmospheric currents. The vessel to be
heated is placed on a ring of supporting studs cor—
responding to its size, and the gas flames thus play
upon the bottom of the vessel. The internal space is
divided into 2 unequal portions by a vertical plate,
and the smaller space is subdivided into 3 portions by
movable shelves. A branch e’ from the main gas-
pipe G, is bent downwards and passes into the bottom
space, terminating in a short horizontal piece carrying
the burners b, the heat from which warms the two
upper chambers 0 c’, in which plates are heated or food
kept hot. This side is closed by a single door. The
larger division has a branch e" from the pipe e, enter-
ing near the bottom and terminating in a rectangular
burner tube R, furnished with a number of burners
inclined inwards. From the division-plate above, a
wire frame or netting n is suspended for carrying the
meat to be roasted, the gravy or dripping falling into
the bottom vessel 1). The upper division 0 is an oven
heated by the same burners R. The whole of this side,
appropriated to roasting or baking, is lined with fire-
brick, which absorbs and then radiates the heat upon
the articles which are being cooked. The bottom of
the oven is also lined with fire-brick. Each burner is
regulated by a stop-cock, and the apertures of the
burners are very minute. The hot air and vapour
escape by the waste pipe is n. This apparatus appears
to be very complete, and it is stated that a dinner for
40 persons has been cooked with it at the cost of only
7 (Z. for gas.
The foregoing examples will sufficientl y indicate the
kind of apparatus employed in warming and cooking
by gas. ‘
Sncrron II.——ON THE vnnrous MEANS rnorosnn on
ADOPTED FOR THE VENTILATION or BUILDINGS.’
The theoretical perfection of ventilation is, to render
it impossible for any portion of air to be breathed
twice in the same building. In the open air, venti-
lation is perfect, because the breath, as it leaves the
body, has always a higher temperature than the air
of any habitable region of the earth. The organs of
respiration are contrived with such marvellous self-
adjusting skill, that while the Esquimaux, who breathes
air at the temperature of zero, has to raise it 98° before
it is expired from his lungs, the inhabitant of the
tropics may have to raise its temperature only 3°. In
England, with a mean temperature of 50°, each indi-
vidual has to warm one gallon of air every minute, on
an average, 48". The whole amount of carbon con-
sumed by the human body does not exceed 9 ounces
per diem, a considerable portion of which is expended
in warming the breath.
This great expenditure of heat and power is for the
purpose of ventilation; for carrying away the noxious
air, and bringing us a supply of fresh. “ This neces-
sary end it effects in the most perfect manner, by
rendering the respired breath more bulky and specifi-
cally lighter than the surrounding fresh air; thus
causing it, immediately on leaving the nostrils, to
ascend, and be replaced by an ingress of _ fresh air,
‘ready to be received at the next respiration.

By;
what other means could the end be insured? Had
the breath been returned from the lungs with its spe-
cific gravity unaltered, the freshness of the next
supply would have depended entirely on the force
with which the previous breath was’7 expelled, the
distance to which it was carried,——the respiration, at
any moment, of wholesome or deadly air would have
depended on mere chance,—-and the stratum of air in
which several persons or animals were collected, would
very soon become irrespirable unless renewed by wind,
which would be as likely to bring worse air as better.
Still more disastrous would be the results if the re-
spired air were denser than the fresh. Accumulating on
the ground in a noxious layer, and left to spread itself
upwards only by the slow process of chemical diffusion
(acting under the most unfavourable circumstances),
or to be stirred up in deadly whiifs by every wind, it
would cover the earth with an universal malaria, and
render the stratum in which animals live the most
unfit portion of the atmosphere to sustain them.
“ But it is another essential feature of this exqui-
site mechanism, that the lightness of the respired air
should be only temporary. It is lighter, only because
warmer than the pure air ; and it preserves its buoy—
ancy only as long as this warmth is not dissipated.
Were it permanently lighter, it would accumulate in
the upper regions, and descending only by chemical
diffusion (acting again under the worst conditions,
and, therefore, with extreme slowness), it would not
be supplied to the vegetable world so quickly as it
now is, and consequently could not be purified so
quickly as it is vitiated by animals; so that the
present equilibrium could not be maintained, but the
whole atmosphere would go on progressively deterio-
rating, and the respirable stratum diminishing in
height. But the vitiated air is, at equal temperatures,
heavier than the fresh; for it contains the whole of
its original ingredients, with the addition of a portion
of carbon, which has been dissolved in it without
increasing its bulk. The change which it has under-
gone in respiration consists in the mechanical addition
of some steam, and the chemical addition of some
carbon. Unless its temperature were altered, the
steam would indeed augment its bulk in a slightly
greater ratio than its weight, and thus render it spe-
cifically a little lighter; but this effect (varying greatly
according to its original hygrometric state) would
never nearly equal the contrary effect of the carbon,
which adds only to its weight, and not at all to its
bulk. On the whole, then, the vitiated air would
sink to the ground were it not for its warmth, to
which alone it owes that ascensional force which
removes it out of the way of second respiration. As
soon as it has cooled to the atmospheric temperature,
this relation is reversed; and the impure air being
now heavier than the pure, but raised above vast
quantities of it, is in the best situation for the speedy
action of that diffusive force by which gases permeate
each other; and the difference of densities, instead of
hindering, promotes this process, and brings down the
carbonic acid within reach of the plants it is to nou~
rish, but in a state so diffused and diluted as to be of
WARMING AND VENTILATION.
921-
the least possible prejudice to animals. We must
never overlook this‘ twofold provision, by which the
breath is, when first exhaled, lighter, but when cold,
heavier than pure air; at first lighter, that it may not
mix with it, but be kept separate and removed out of
our way; but afterwards heavier, that it may not accu-
mulate, but be mixed and diluted, and repurified as
soon as possible.” 1
If the ventilation is thus perfect in the open air, it
is miserably imperfect in most human habitations.
Within doors, the same law is in action as without.
The hot breath ascends, and would escape if proper
channels were provided for its exit, and due provision
were made for the entrance of fresh air below. But
in our flat, ceiled rooms, where there is no escape for
the heated, and consequently the lightest air of the
room, it becomes cooled, and is soon the heaviest: it
descends to be breathed over again, and in this con-
dition it acts as a poison.
It is the undisputed opinion of medical men who
have studied this subject, that the breathing of bad
air is a more fruitful source of disease than any other.
Dr. Arnott, in a letter to the Times newspaper of the
22d September, 1849, says :——-“I assume that your
readers know that fresh air for breathing is the most
immediately urgent of the essentials to life, as proved
by the instant death of any one totally deprived of it
through drowning or strangulation ; and by the slower
death of men compelled to breathe over again the
same small quantity of air, as when lately seventy—three
passengers were suffocated in an Irish steam~boat, of
which the hold was shut up for an hour by closely
covered hatches ; and by the still slower death, accom-
panied generally by some induced form of chronic
disease, of persons condemned to breathe habitually
impure air, like the dwellers in crowded, ill-ventilated
rooms, and foul neighbourhoods; and, lastly, as proved
by the fact, that pestilence 'or infectious diseases are
engendered or propagated almost only where impurities
in the air are known to abound, and particularly where
the poison of the human breath and other emanations
from living bodies are allowed to mingle in consider-
able quantity—as instanced in the gaol and ship fevers,
which so lately, as in the days of the philanthropist
Howard, carried off a large proportion of those who
entered gaols and ships; and as instanced in that
fearful disease, which, at the Black Assizes at Oxford,‘
inJuly 1577, spread from the prisoners to the Court,
and within two days had killed the judge, the sheriff,
several justices of the peace, most of the jury, and a
great mass of the audience, and which afterwards
spread among the people of the town. This was a
fever which did its work as quickly as the cholera
does now. Assuming that these points are tolerably
understood, I shall proceed to show, that from faults
in the construction and management of our houses,
many persons are unconsciously doing, in regard to
the air they breathe, nearly as fishes would be doing
in regard to the water they breathe, if, instead of the
pure element of the vast rivers or boundless sea

(1) From a paper on Ventilation, in “ The Architect ” for 1850.

streaming~ past them, ,theyshut themselves up in
lioles near the shores, filled with water defiled by
their own bodies, and from other foul sources. And
I shall have to show, that the spread of cholera in
this country has been much influenced by the gross
oversights referred to. All the valued reports and
published opinions on cholera go far to prove, that, in
this climate at least, any foreign morbific agent or
influence which produces it, comes comparatively
harmless to persons of vigorous health, and to those
who are living in favourable circumstances 5 but that
if it find persons with the vital powers much de-
pressed or disturbed from any cause, and even for
a short time, as happens from intemperance, from
improper food or drink, from great fatigue or anxiety,
but, above all, from want of fresh air, and, conse-
quently, from breathing that which is foul, it readily
overcomes them. It would seem as if the peculiar
morbid agent could as little, by itself, produce the
fatal disease, as one of the two elements concerned
in a common gas explosion, namely, the coal gas and
the atmospheric air, can alone produce the explosion.
The great unanimity among writers and speakers on
the subject, in regarding foul atmosphere as the
chief vehicle or favourer, if not a chief efficient
cause of the pestilence, is seen in the fact, of how
familiar to the common car have lately become the
words and phrases, malaria, fill/lay crowded dwellings,
crowded aez'g/tboarlzoods, close rooms, faallg/ sewers,
drains and cesspools, or lolal waal of these, eflavz'a of
graveyards, &c., all of which are merely so many
names for foul air, and for sources from which it may
arise. Singularly, however, little attention has yet
been given from authority to the chief source of
poisonous air, and to means of ventilation by which
all kinds of foul air may certainly be removed.
“ A system of draining and cleansing, water-supply
and flushing, for instance, to the obtainment of which,
chiefly, the Board of Health has hitherto devoted its
attention, can, however good, influence only that
quantity and kind of aerial impurity which arises from
retained solid or liquid filth within or about a house,
but it leaves absolutely untouched the other and
really more important kind, which, in known quantity,
is never absent where men are breathing, namely, the‘
filth and poison of the human breath. This latter
kind evidently plays the most important part in all
cases of a crowd. and, therefore, such catastrophes as
that of the Tooting school, with 1,100 children, of
whom nearly 300 were seized with cholera, of the
House of Refuge for the Destitute, and of the two
great crowded lunatic asylums here, where the
disease made similar havoc,—for places so public as
these, and visited daily by numerous strangers, could
not be allowed to remain visibly impure with solid
and liquid filth, like the Rookery of St. Giles’s, and
other such localities. Now, good ventilation, which,
although few persons comparatively are as yet aware
of the fact, is easily to be had, not only entirely dis~
sipates and renders absolutely inert the breath-poison
of inmates, however numerous, and even of fever
patients ; but in doing this, it necessarily at the same
922; A ND VENTILATION‘.
WARMING .
time carries away at once all the first-named kinds of
poison, arising from bad drains, or want of drains, and
thus acts as a most important substitute for good
draining, until there be time to plan, and safe oppor-
tunity to establish such. It is further to be noted,
that it is chiefly when the poison of drains, &c., is
caught and retained under cover, and is there mixed
with the breath, that it becomes very active, for
scavengers, nightmen, and gravediggers, who work in
the open air, are not often assailed with disease: and
in foul neighbourhoods, persons like butchers, who
live in open shops, or policeznen, who walk generally
in the open streets, or in Paris, the people who manu-
facture a great part of the town filth into portable
manure, suffer very little.”
But as most persons pass a very large portion of
their time within doors, and at least one-third of their
existence in bed-rooms, it becomes of the utmost im-
portance that these rooms should be tolerably healthy:
and such they cannot possibly be unless provision be
made for the escape of foul air, (2'. 6. air that has been
breathed once, or has once served to support combus-
tion,) and the entrance of fresh.
A. large number of plans for ventilation have been
proposed; but they may all be divided into two
classes, natural and artificial. Natural ventilation
resembles the process as it'is carried on out of doors;
no machinery is used to draw the foul air out, or to
pump in fresh; but the heated products are con-
ducted away by channels opening from the highest
part of the room, and fresh air is admitted by open-
ings in the lowest part. 'In artificial ventilation, the
air is set in motion by machinery, or by the action of
‘heat or steam artificially applied. Artificial ventila-
tion is by some writers divided into plenum and vacuum.
In plenum ventilation, pure air is forced by machinery
into the building, and the vitiated air is left to escape
by channels made for the purpose, or by crevices in
the doors, windows, &c. In vacuum ventilation, the
interior air is exhausted or drawn out of the building,
the fresh air being allowed to enter by proper chan-
nels. These distinctions are not of very great impor-
tance, and we shall not be particular in observing
them.
The first consideration in ventilating a building is
as to the quantity of fresh air required to be intro-
duced. Tredgold estimates that for each individual
there should be provided 4i cubic feet of fresh air per
minute. This supposes, not ‘that each individual’s
respiration converts in one minute the oxygen of
.41 cubic f ect of air into carbonic acid, but that 3 cubic
feet of air are contaminated in the process so as to
be unfit for respiration, and that 1 cubic foot of air is
rendered equally unfit by the combustion of one
‘candle. Hence, a room containing 200 persons will
require to have 800 cubic feet of air passed through
it in that time, or rather more than would fill a room
.9 feet square, and 9 feet high.
The form of ceiling best adapted to ventilation is
the domed, coved, arched, or groined, from the most
elevated point of which’ should proceed a tube or
shaft, leading to a chimney or air-flue erected at the _

side of the smoke chimney, the warmth of which will
increase the force of the ascending current. The
amount of ventilation may be regulated by a plate a,
Fig. 2267, balanced by a weight attached to a cord or
wire a passing over a pulley p, ‘
suspended from s, and‘ capable of
being moved by a handle in the
room. In the arrangement shown
in Fig. 2267, the ventilation is
supposed to be let into the


.__.-»'
wall 2020. It is more difficult to
ventilate in summer, than in
winter. There should not in
warm weather be a greater dif- Fig.226.'
ference than 10° between the air inside and that
out, and on this datum Tredgold gives the follow-
ing rule for finding the area of the ventilating
tubes :—--Multiply the number of persons who are
to occupy the room by 4‘, and divide this product
by 413 times the square root of the height of the
tubes in feet, and the quotient is the area of the ven-
tilator tube in feet. The height of the tubes is esti-
mated i'rom the floor of the room to the place where
the air escapes into the atmosphere; and where there


-___
llllll

In


'L-_
M


Fly. 2268. Fig. 2269.
are more tubes than one, they should all be of the
same height : otherwise cold air will blow down some
of them, or the effect of the shorter tubes will be less
than that of the others. Several tubes from the same
level may, however, open into one common shaft, and
this may be furnished with a vane, to turn its aper-
ture from the wind, or a top of thin metal painted of
a dark colour may be used, as in Fig. 2268. ,The
upper cap prevents wind from blowing down the
shaft. In a steady horizontal wind the cap is not
wanted, for the wind moving in the direction shown
by the arrow in Fig. 2269, is deflected and rises over
the opening of the shaft, drawing the air out of the
flue, instead of impeding its exit. The shaft must
not be top large, or a double current or eddies will be
formed in it.
The spaces for admitting fresh air should be near
or in the floor; and these should present the same
area as the exit tubes, or even larger, to prevent a
rapid influx of air.
In hospitals, infirmaries, &c., Tredgold recommends '
an increase of ventilation, and names 6 feet per mi-
nute for each individual.‘ -
_WARMING AND VENTILATION:
923
In perfect ventilation, the impure or noxioug air
is removed as soon as it is produced, and therefore, in
any good system, the ventilating force should always
be in action‘; and this is especially the case in places
where the air is tainted by disease. The tendency of
airs to mix is increased by agitation; hence the air
should not be agitated, except when it is passed in
large quantities through the wards for the sake of
purification.
In any natural system of ventilation, where the air
is left to escape by its own levity, the discharge tubes
should be of uniform diameter, since any enlargement
produces eddies and interrupts the discharge. Each
tube should be distinct in itself, for if currents be let
into it from different apertures, they cross each other
and intei'rupt the flow.
The ventilating flue is subject to the same laws as
those which regulate the chimney. [See CHIMNEY]
Air expands about $0 th of its volume for a degree
of Fahrenheit from 32° to 212°. Now, if a ventila-
ting flue 10 feet high have the air contained in it
raised 20° above the temperature of the air outside,
the expansion due to this increase of temperature
would be z-Q-g‘éaths, or gzth of its bulk. This would so
far diminish the density of the heated column, that
it would require 10% feet thereof to counterbalance a
height of 10 feet of the outer air. In chimneys, the
velocity of eiliux is equal to that of a heavy body
falling through the difference in height of the two
columns, and in the present case, the difference of
5 inches is equal to 5 '17 4_feet per second, or 310 feet
per minute, and this is the velocity with which a
heated column of air would pass through the ventilat-
ing tube; and if the sectional area of this be 1 foot
square, then 310 cubic feet will, according to this
calculation, escape per minute. A deduction from
this of i—th to 55d must be allowed for friction due to

roughness in the tube, or angles or bends in it, or to
the pressure of minutelyedivided carbon in the air,
whereby its density is increased.1 The number of
cubic feet of air per minute discharged by a venti-
lating shaft is equal to 8 times the square root of the
difference in height of the 2 columns of air in deci-
mals of a foot. This number, reduced 5th for fric—
tion, and the remainder multiplied by 60, gives the
rate of effiux per minute, and the area of the tube in
feet or decimals of a footmultiplied by this last num-
ber, gives the number of cubic feet of air discharged
per minute.
The lower openings for the admission of fresh air
must be of larger area than those for the escape of
the hot air; otherwise there will be a double current
established, cold air passing down one part of a
ventilating shaft while hot air is ascending through
the same shaft. In churches and crowded assemblies
where the only means of ventilation in summer is by
open windows, these double currents may be noticed,
the same aperture admitting fresh and allowing foul
air to escape, thus exposing persons near to dangerous

(1) The laws which regulate the draught of air-‘flues and chim-
neys are well discussed in Mr. Hood’s work already referred to.

draughts, and cooling the foul air, so as to prevent
its escape.
In the ventilation of a church, or other public
building, Tredgold advises that the spaces for the ad-
mission of cold air be abundantly large, and divided as
much as possible; they should be in or near the floor,
so that the air may not have to descend upon the
heads of the congregation. By making the openings
large, and covering them on the inside with rather
close wire-work (ea apertures to the square inch),
most of the current may be prevented; and it may be
still further prevented by bringing tubes under the
paving to admit fresh air into the central parts of the
church. Of course these openings must be provided
with shutters, so as to close them when desirable.
Where the vent tubes can be carried up vertically
from the ceiling to the top of the building, it is better-
to do so, because the friction of the hot ascending
current is thereby diminished. If the vent be made
through the ceiling of a church into the space in the
roof, and. from this space an air-tube be taken up
within the steeple or bcll~turret, an effectual ventila-
tion may be obtained without adding outlets to the
roof: or a common louvre-boarded top will answer
for an outlet from the roof. All side and end win—
dows should be kept closed; for if the apertures at
the ceiling be of the proper size, and due provision
be made for supplying fresh air, these open windows,
as already explained, will diminish, not increase, the
amount of ventilation. The reason has been already
stated why ventilation is difficult to maintain in warm
weather. Of course, it becomes especially so in very
calm warm weather. Mr. Tredgold gives a case of
this kind :--Suppose we wish to provide ventilation
sufficient to prevent the internal air from being of a
higher temperature than 5° above that of the external
air. Now, if the external air he at 70°, we shall not
be able to keep the internal temperature down to 75°
with a less escape of air than 2;— cubic feet per minute
for each person; because each person will heat, at
least, that quantity of air 5° in a minute, at these
temperatures. When a church contains 1,000 per-
sons, and the height from the floor to the top of the
tube is 49 feet, the sum of the apertures that- will
allow 2,500 cubic feet of air per minute to escape,
when the excess of temperature is 5°, must be equal
to 12 square feet. If the height be only 36 feet, the
size of the aperture must be M square feet nearly.
Virhen the ceiling is level, this area should be divided
among five or more ventilators, disposed in different
parts of the ceiling; but in a vaulted or arched roof,
three are recommended to be placed in the highest
part of the ceiling, as at v, in Fig. 2270. The form
. \'-_‘~ ~ ' .‘Q ‘Q. all‘. Q



Fig. 22 70.
of the mouth of the vent tube, is a circular aperture,
with a balanced circular register plate, r, Fig. 2210, to
924'!
WARMING AND VENTILATION.
close it. This plate should be larger than the aper-
ture, in order that the air may be drawn into a hori—
zontal current, for the purpose of taking away the
portion of air next the ceiling. If the tube were left
without a plate, the air immediatelyr under it would
press forward up the tube, and very little of the worst
air which collects at the ceiling would escape. There
is, however, a defect in Tredgold’s figure, since he
makes the timbers clip on each side of the ventilating
opening, as is indicated on one side by the dotted
lines 2‘, Fig. 2270. Such an arrangement as this ought
always to be avoided, as it prevents the free passage
of the air, and causes a stratum near the ceiling to cool
before it has time to escape up the opening.
In Mr. Tomlinson’s work on Warming and Ventila-
tion,1 a sectional elevation is given of a church, show-
ing the ventilating arrangements, and it is remarked,
that, “ in designing and constructing a new building,
fines might be made for the special purpose of sup-
plying ihe interior with fresh air. Each flue might
open in the cornice, pass down between the piers, and
under the flooring of the church or other building, and
terminate in apertures which would be covered with
gratings. By disposing some of these flues on each
side of the church, they would act with the wind in
any direction. These exterior openings should, how-
ever, be covered with a grating, to prevent birds from
building in them, and thus stopping them up.”
Professor Hosking states from his own inspection,
that in the churches, chapels, lecture rooms, concert
rooms, 82:0. of the metropolis, frequently the most
expensive apparatus is employed for making hot the
air which is to be admitted, “ but it is rare indeed to
find an instance of both inlet for fresh air, whether tem-
pered or not, and a way of escape for spent air, both
in the same building; whilst the application of power
either to establish and maintain the up-draught, or to
force tempered air into the building, is hardly to be
found at all.” The same author remarks, that one
essential condition to the thoroughly wholesome ven-
tilation of a building is, that its drains be themselves
efficiently ventilated. “Effectual scavengering is the
first essential to wholesome ventilation.” He also
suggests that as most church clocks have a super-
abundance of power beyond their ordinary work, they
would have enough to spare to work a pump or fan,
for drawing off foul air.
The true principle of ventilation, as already stated,
is to admit the fresh and denser air at as low a point
as possible in the building which is to be ventilated,
and to let out the vitiated and lighter air at the high-
est point of the ceiling or roof into the open air. A

(l) “Treatise on Warming and Ventilation, being a concise
exposition of the General Principles of the Art of Warming and
Ventilating Domestic and Public Buildings, Mines, Lighthouses,
Ships, 850.” Published (1850) in Weale’s Rudimentary Series.
Iii-the preparation of this article we have been indebted to the
above work, as also to Tredgold, “Warming and Ventilation,”
London, 1836 ; Professor Hosking, “ Healthy Homes,” 1849; Burn,
“ Practical Ventilation,” 1850; Beman, “ History and Art of
Warming and Ventilating,” 8:0. 1845. The “Mechanic’s Maga-
.zine,”'and ‘the " ‘ Civil Engineer and Practical Mechanic’s Journal,”
. contain mostjof the currentimprovements in theart. ‘

number of modern contrivances completely overturn
this fundamental principle of sound ventilation by
admitting fresh air at a point near the ceiling, or from
the top window-pane furthest from the fire. Thus,
a writer, who is usually sound, recommends that a
space of g to % an inch be left at the top of doors and
in windows on those sides of the house which faced
the points from which the mildest wind blew, and
half as much space facing the north. “The advan-
tage,” he says, “ of receiving fresh air at the upper
part of the room is, that it comes immediately in con—
tact with the hottest air of the room, and is thus
rendered temperate before it reaches persons seated
in the middle of the room or near the fireplace;
whereas, when the air is admitted or drawn in by
the bottom or lower parts of doors or windows, it
slides along the floor towards the fireplace to supply
the draught, at once cooling the feet of every one in
the room, and leaving the great body of air of the
apartment entirely unchanged.” That which the
writer calls an advantage is indeed a very serious
error, for by admitting the fresh air at the upper part of
the room, it certainly does come in contact with the
‘hottest air of the room, and it is precisely this hottest
air which ventilation ought to - get rid of, for it is
charged with the fetid products of respiration and
combustion ; and the effect of ~letting in cold air upon
it is to cool and condense these products, and cause
‘them to descend to be breathed over again. This ob-
jection applies to all those arrangements of perforated
zinc, glass louvres, perforated glass, 850., when they
let in cool air instead of letting out the used air.
And that the object is to let in cool air is evident
from the statement of the inventors. Thus, in one
form of ventilator, a frame of glass is hinged at the
top, and moves outwards at the bottom, by the
action of a quick-threaded screw, so as to form a
hanging valve: an inside half—pane is arranged so as
to direct the cold air upwards, so that it may be dif-
fused over the room without creating any unpleasant
draught. It is evident that by this arrangement the
bad air, which ought to be removed, is cooled down
by the entrance of fresh.
When it is stated that fresh air should be admitted
at a low level in the room or building, it need not, of
course, be drawn from a low level, where it is liable
to contamination. It maybe drawn from a consider-
able elevation, and still oe admitted into the room at
a low level. In building new houses air-ducts should
be formed in the walls with the entrance just below
the eaves. In old houses the air-ducts may be formed
of zinc or iron pipes, or they may be wooden trunks;
they should have fine wire gauze, perforated zinc, or
other material stretched across them to filter the air
from dust, &c. The number and position of these
openings will of course depend on the amount and
kind of ventilation required. Each opening may be
about 6 inches in length, and 1%,- inch in breadth, and
at the place where it opens into the apartment the

(2) London :
“ Cyclopeedia of Cottage, Farm, and Villa Archi-
tecture.” , - . -. . .
WARMING AND VENTILATION.
925
skirting board may be perforated with small holes;
or better still, the skirting board at this place may be
tilted a little forward from the top, and the opening
or end of the air-tube be covered with wire gauze or
hair cloth, &c. This will effectually prevent cold air
from streaming to the feet, and yet its entrance will
be sufficiently low for the useful purposes of ventila-
tion. The air~tube may be made to open at any other
part of the room with equal facility: it may be led
into the centre of the apartment, the floor being
pierced for its reception, in which case the carpet will
assist in diffusing it over the room. In new houses
the ventilating bricks [see Porrnnr AND PORCELAIN,
Sec. 111.] may be applied for making the air-ducts
and for other ventilating openings. All these open-
ings should, of course, be provided with flaps, so that
they may be wholly or partially closed according to
circumstances.
Any system of natural ventilation is liable to be
modified according to the nature of the case. In
Messrs. Rowan and Son’s mill, at Millwater, near
Belfast, the openings for the escape of foul air are
furnished by the hollow iron columns which support
the building. These are set as usual one above
another throughout the several stories, the top of one
column being connected with the bottom of the
column next above it, so as to form a continuous
vertical canal from the basement to the roof. Near
the top of each column is an opening fitted with a
trumpet mouth, into which the vitiated air passes and
is carried off at the top.
Ventilation assisled 6y arlifieial leak—In natural
ventilation the products of respiration and of combus~
tion are supposed to have sufficient ascensive force
to escape of themselves through openings provided for
the purpose. It may, however, happen that in the
arrangements of our buildings, in the state of the
wind or weather, or other causes, the shafts have not
sufficient draught to discharge the foul air. In such
a case, or in the first instance, to prevent the risk of
failure, artificial heat may be applied to assist the
draught of the foul-air fine. We have already sug-
gested its erection next to the smoke-flue for the
sake of the warmth afforded by the latter; but Dr.
Arnott recommends that the smoke-flue itself be
employed as the ventilating shaft. This suggestion
is so valuable, and in many cases the only practicable
means of drawing off foul air,——it is moreover so cheap,
effective and ready in its adoption, that we are anxious
to give the method all possible prominence, and we
cannot do better than quote the words of the bene-
volent inventor. mAfter admitting that with badly
drained houses and streets, a deficient supply of water,
crowded rooms, &c., ventilation cannot do more
than dilate the aerial poisons, he says :-_-—“ Every
chimney in a house is what is called a sucking or
drawing air-pump, of a certain force, and can easily
be rendered a valuable ventilating pump. A chimney
is a pump—first, by reason of the suction or approach
to a vacuum made at the open top of any tube across
which the wind blows directly; and, secondly, because
the flue is usually occupied, even when there is no

fire, by air somewhat warmer than the external air,
and has, therefdre, eveir in a calm day, what is called
a chimney draught proportioned to the difference. In
England, therefore, of old, when the chimney breast
was always made higher than the heads of persons
sitting or sleeping in rooms, a room with an open
chimney was tolerably well ventilated in the lower
part, where the inmates breathed. The modern
fashion, however, of very low grates and low chimney
openings, has changed the case completely, for such
openings can draw air only from the bottom of the
rooms, where generally the coolest, the last entered,
and therefore the purest air, is found; while the
hotter air of the breath, of lights, of warm food, and
often of subterranean drains, &c., rises and stagnates
near the ceilings, and gradually corrupts there. Such
heated, impure air, no more tends downwards again
to escape or dive under the chimney-piece, than oil in
an inverted bottle immersed in water will dive down
through the water to escape by the bottle’s mouth;
and such a bottle or other vessel containing oil, and
so placed in water with its open mouth downwards,
even if left in a running stream, would retain the oil
for any length of time. If, however, an opening be
made into a chimney flue through the wall near the
ceiling of the room, then will all the hot impure air
‘of the room as certainly pass away by that opening,
as oil from the inverted bottle would instantly all
escape upwards through a small opening made near
the elevated bottom of the bottle. A top window-
sash, lowered a little, instead of serving, as many
people believe it does, like such an opening into the
chimney flue, becomes generally, in obedience to the
chimney-draught, merely an inlet of cold air, which
first falls as a cascade to the floor, and then glides
towards the chimney, and gradually passes away by
this, leaving the hotter impure air of the room nearly
untouched. I
“ For years past, I have recommended the adoption
of such ventilating chimney openings as above de-
scribed, and I devised a balanced metallic valve, to
prevent, during the use of fires, the escape of smoke
to the room. The advantages of these openings and
valves were soon so manifest, that the referees ap-
pointed under the Building Act added a clause to their
bill allowing the introduction of the valves, and direct-
ing how they were to be placed, and they are now in
very extensive use. A good illustration of the subject
was afforded in St. James’s parish, where some quarters
are densely inhabited by the families of Irish labourers.
These localities formerly sent an enormous number of
sick to the neighbouring dispensary. Mr. Toynbee,
the able medical chief of that dispensary, came to
consult me respecting the ventilation of such places,
and, on my recommendation, had openings made into
the chimney fines of the rooms near the ceilings, by
removing a single brick, and placing there a piece of
wire gauze, with a light curtain flap hanging against
the inside, to prevent the issue of smoke in gusty
weather. The decided eflect produced at once on the
feelings of the inmates was so remarkable, that there
was an extensive demand for the new appliance, and,
‘926
WARMING AND VENTILATION.
‘as a consequence of its adoption, Mr. Tcynbee had
soon to report, in evidence given before the Health
of Towns Commission, and in other published docu~
ments, both an extraordinary reduction of the number
of sick applying for relief, and of the severity of
diseases occurring. Wide experience elsewhere has
since obtained similar results. Most of the hospitals
and poor-houses in the kingdom now have these
chimney-valves; and most of the medical men and
others who have published of late on sanitary matters,
have strongly commended them. Had the present
Board of Health possessed the power, and deemed the
means expedient, the chimney openings might, as a
prevention of cholera, almost in one day, and at the
expense of about a shilling for a poor man’s room,
have been established over the whole kingdom.”
The plan of ventilating by means of the chimney
draught is by no means new. Dr. Arnott’s applica-
tion of it is new, and superior in simplicity to any
other that we are acquainted with. The Arnott valve
consists of a cast-iron box, of an oblong form, open at
the two ends, and of a depth sufficient to occupy that
small portion of the brickwork of the flue, which is
removed for its reception. It should be placed in the
fine as near the ceiling of the room as possible, and
be bedded in with plaster, so that its outer edge may
.be flush with the wall of the room. Just within this
box is placed on edge a plate of iron, sufficient to fill
the opening, which plate is held in its place by means
.of an oblong frame, attached by thumb-screws, passing
through it into the sides of the box. Projecting
from the plate into the room is a short arm, the free
end of which is furnished with a screw and a metal
knob; By turning this knob round upon the screw,
higher or lower, the specific gravity of the plate may
be so nicely adjusted, that while the heated products
of respiration and combustion of the room ascending
to the ceiling, are sufficient to force open the valve,
and escape into the chimney, any down-draught, or
puff of smoke in the contrary direction, closes the
‘valve on the other side, and prevents smoke and soot
from. entering the room. A spring wire is attached
to the plate, and passes down to within a few inches
of the mantelpiece, where it terminates in a slow
threaded screw moving in a nut, fixed to the wall.
On turning this screw in one direction, the valve may
be permanently closed. It is of importance that the
valve be nicely balanced on its edge, otherwise the
down-draught of the chimney will not close it soon
enough to prevent a puff of smoke into the room.
In cases where this valve does not act satisfactorily,
it will generallybe found that the fire of the room is
not well supplied with air. Where several valves are
fitted to the chimneys of the same house, it will often
be found that while one acts efficiently, the others
will act badly. The chimney fine in the one case
will probably be found to appropriate to itself the
larger share of the air of the house, leaving the other
fines imperfectly supplied. These evils, together with
the cutting draughts from cracks of doors and chinks
of windows, scarcely admit of remedy, unless proper
provision be made for. supplying every fireplace. with

air, after some such plan as that adopted in the
Polignac stove.1
The Arnott valve may be fitted up complete for about
108. A much cheaper form has been contrived by Mr.
Toynbee. It consists of a tube of iron, from 3 to 6
inches in diameter, sufficiently long for one end to
remain flush with the wall of the apartment, while
the other enters the chimney. The orifice of the tube
in the room is covered with
a sheet of perforated zinc, or
of wire gauze, from the upper
and back part of. which hangs
a flap of oiled silk, which acts
as a valve, so as to allow
the vitiated air .to pass up
the chimney, and prevent the
smoke from returning into the
room. Fig. 2271 shows the arrangement of this
valve, 20w represent the wall, with the iron box or
tubein it, a the sheet of zinc or gauze, and s the
flap of silk.
Another modification of the Arnott valve is Teal’s
T/zermomelrlc Ventilator. This consists of a circular
disk, like an ordinary damper or throttle-valve of a.
steam-engine, accurately balanced on a spindle carried
in delicate bearings. On one side of it is an inverted
syphon, with a bulb at one end, and open at the other.
The lower portion of the Syphon-tube contains mer‘-
cury, while the bulb is filled with air. Any increase
of temperature expands the air in the bulb, and drives
the mercury down one leg of the syphon tube, and up
the other, thus disturbing the balance of the valve,
which, by its partial revolution, opens the air passage:
Should the temperature of the room fall, the air in
the bulb contracts, the mercury rises, and turns over
the valve so as to reduce the air passage.
Many years ago Tredgold proposed to ventilate a
room by means of its chim-
ney, for which purpose be
used an inverted syphon,’
Fig. 2272, one leg of which
was to be placed in the
chimney, so near to the fire
as to make the air in that
leg warmer than that in
the other, (as at y, where
it is supposed to be in
contact with the side or
back of the grate,) in
which case a current would
be established, the air as-
cending in the warm limb
and passing up the chirm
ney, while a descending
current in the cooler limb would take the place of
s53“
st
Fig. 2271.


(l) “ Let it be well and clearly understood, that any success in
promoting tip-draught, with the effect of removing foul air from
the inside of a house, will be most assuredly followed by down-
draught in the chimney fines, and consequently smoky chimneys
if there be fires, and soot if there be none, unless ample provision
have been made for iii-draught of air below, to feed any fires, and
to supply the place of What the tip-draught may take away.”—
‘ Hoslaing, Healthy Homes. _ -
WARMING AND
VENTILATION. 927
the air in the room. The mouth of the cooler
limb a, is to be situated close to the ceiling of
the apartment, the lowest point of the curve ll: being
below y, where heat is applied, and the aperture
through which air flows into the chimney, as at a,
should be formed so that soot may not enter it. In
the figure an inverted cone is used for this purpose.
The mouth of the tube should alsqbe fitted with a
register, to regulate the amount of ventilation.
The practice of ventilation by means of artificial heat
is probably as old as the art of mining. The miner work—
ing in his long underground galleries is compelled to
adopt some method of ventilation, in consequence of
the rapid conversion of the oxygen of the air into car~
bonic acid, occasioned by respiration and the combus-
tion of candles and of the gunpowder used in blasting.
In the analysis of 18 samples of air from the mines of
Cornwall and Devon, Mr. Henwood found the pro-
portion of oxygen to be only 17067 per cent., while
the carbonic acid was 0085 ; the nitrogen 82848.
In one instance the oxygen was 14:51, and in another
the carbonic acid 023 per cent. These results show
a diminution of oxygen from its usual per-centage of
21, and an increase of carbonic acid from 0'01, its
usual per-centage, to a proportionwhich must be highly
dangerous. The art of ventilating mines is described
under COAL, but we may here mention that so long
ago as the sixteenth century, Agricola, in his book De
Re Mez‘alh'ca, notices the method of drawing foul air
out of a mine by suspending a large fire in the middle
of one of the shafts. This principle does not appear
to have been adopted for ventilating crowded rooms
until the year 1723, when Dr. Desaguliers was
requested to endeavour to improve the mode of ven-
tilating the House of Commons. The plan then in
use had been introduced by Sir Christopher Wren,
and it consisted in forming a large square hole in the
ceiling at each corner of the house, and-over each
hole in the room above was placed a hollow truncated
pyramid 6 or 8 feet high, and made so as to be closed
when desired. The hot air of the house escaped by
.these openings, but we are not informed whether it
was discharged into the open air, but only that on
certain occasions the cold air above stopped the
ascending currents, and sometimes poured down cold
air upon the members below. The remedy contrived
by Dr. Desaguliers was to construct a closet at each
end of the upper room between the pyramids, and to
conduct a trunk from the pyramids to certain square
iron cavities which surrounded a fire-grate in each
closet. When these fires were burning, air ascended
from the house into the closets, then through the
heated cavities, and so up the chimneys. This is a
very sensible arrangement, and, we doubt not, effective.
It failed, however, from a cause which we leave the
author to describe in his own words :-—-“ Mrs. Smith,
the housekeeper, who had possession of the rooms
over the House of Commons, not liking to be disturbed
in her use of those rooms, ‘did what she could to
defeat the operation of these machines; which she at
last compassed by not having the fire lighted till the
House had sat some time, and was very hot; for then ‘

the air in the closets that had not been heated, went
down into the House to an air rarer and less resist;
ing, whereby the House became hotter instead of
being cooled. But; when the fire had been lighted
before the meeting of the members, the air went up
From the House into the closets and out of their
chimneys, and continued to do so the whole day,
keeping the House very cool.” 1 .
In the middle of the last century a very sensible
plan was contrived by a man named Sutton, for the
ventilation of ships. It was proposed to lead pipes
from those parts of a ship that required ventilating to
the galley fire, the draught of which would draw oil’
the bad air. A number of experiments were tried on
board a ship in the presence of some influential persons,
and Mr. Watson the electrician reported thereon. He
describes the copper used for boiling the ship’s pro-
visions, and the method of fixing it, with two open~1
ings below, divided by an iron grate. The first
opening, having an iron door, is for the fire, the other
for the ashes. In ordinary cases, the combustion of
the fire is supported by air drawn through the ash-pit;
but, on board ship, as both the fire hole and the ash-
pit hole are furnished with doors to prevent the escape
of fire, the air must be supplied by some other means.
Accordingly, in Sutton’s plan of ventilation one‘ or
more holes are made through the brick—work in the
side of the ash-pit, and tubes of lead or copper are
fitted closely therein, and conducted from thence into
the well, and other parts of the ship; thus drawing
ofi' therefrom the foul air, and sending it through the
fire, it escapes up the chimney. At the same time, a
supply of fresh air rushes in at openings about the
ship, to occupy the place of the bad air. This circu-
lation of air not onl goes on while the fire is burning,
but so long as the fire-place, copper, or brick-work
remains warm, as was observed on board the bulk at
Deptford, when the draught of air through the tube
lasted above twelve hours after the fire was taken
away. “ This being considered, as the dressing the
provisions for a number of people will take up some
hours every day, the warmth of the brick-work and
fines will continue a draught of air from one .day to
the next. Mr. Sutton proposes thus to circulate the
air by the same and no greater expense of fire, than
is customarily used for the necessities of the ship."
The larger the ship, the greater the number of men
on board, and the larger the quantity of prpvisions,
so that more time and fuel will be required in prepar-
ing them, the more perfect will be the ventilation.
The size and number of the tubes is of little con-
sequence, for the larger the tubes, and the greater
their number, the less the velocity of the air, and
vice cersrZ. Mr. Watson notices, as an essential con-
dition of the perfect action of the tubes, that both
the fire door and the ash-pit door be kept closed. In
large ships there is not only a copper, but also a fire-
grate like that used in kitchens. Behind this grate,
copper tubes were also fixed and carried through the
brick-work, one extremity projecting about a foot

(1) Course of Experimental Philosophy, vol. 41:0. 176%,.
928
WARMING AND VENTILATION.
into the chimney, and the other end opening into the
hold, or other part of the ship ; so that the air rushed
along this tube into the draught of hot air in the
chimney. To obviate the objection to the space
occupied by these tubes on board ship, it was advised
that only one tube, of convenient size, be attached to
the side of the ash-pit, and, passing through the main-
deck, branches might ramify to different parts of the
ship, these branches being carried between ‘the beams
which support the deck, until they meet the sides of
the ship, where they could be conducted also between
‘the beams into the places intended.
Such a plan as this is well adapted to the ventila-
tion ‘of steamers. vA. large central trunk might be
made to‘feed the furnace, and into this trunk smaller
branches from every cabin and sleeping birth might
discharge their foul air, and thus maintain every part
of the vessel in a state of perfect salubrity. Although
Sutton’s plan is forgotten (indeed, it can never be said
to have been in use) on board ship, it has been ap-
plied for getting rid of the offensive efflnvia from the
coppers of soap-boilers, tallow-melters, and similar
occupations, which often become a nuisance to a
whole neighbourhood. The copper is set in the usual
manner, and the. furnace and ash—pit furnished with
doors, tightly fitting; the lid of the boiler is also
made to fit very tight, and a. pipe rising from it is
carried into a channel which opens into the ash-pit;
~the foetid matters rising from the boiler are in this
1 way madeto pass through the fire into the smoke-flue.
This plan is‘ said .to have answered so well that a
factory which was’ formerly most offensive, became
entirely free from bad odours.
It does not say much’ for the science or for the
-_common sense of the age, that the plan of Dr. Desa-
guliers for ventilating a-large public room,and Sutton’s
plan for ventilating ships, so correct as they were both
in theory and practice, should have failed. When Sir
Humphry Davy in 1810 was requested by the Govern-
ment to propose. a plan for the ventilation of the
House of Lords, he sent in one which was identical
in principle with that by which Desaguliers ventilated
the House of Commons ; Davy’s plan, however,
included warming as well as ventilating, and is thus
stated by himself:—“ To convey fresh air into the
House, I propose fines of single brick connected with
the fines for sending hot air through the vaults under
the floor, and I propose that this fresh air should be
admitted by numerous apertures in the floor of the
.House, and supplied to the fines by pipes of copper
or plate iron from the free atmosphere. The air in
'this case will be always fresh, and, by regulating the
fire, may be more or less heated, according as the
temperature of the room is low or high.
“ To carry off the foul air, I propose two chimneys,
or tubes made of copper, placed above the ventilators,
and connected with wrought-iron tubes, which can be
heated by a small fire, if a great draught is necessary,
as in cases when the House is full.
“ Should this plan be adopted, there would be no
necessity for opening windows; the foul air would be
carried 0E from above; warm air or cold air, which—

ever is necessary, may be supplied from below, and
there would not be, as now, any stagnation of air.”
This plan was accompanied by a sketch, of which
Fig. 2273 is a
copy, in which v
is one of the ven-
tilating apertures
in the ceiling
of the House,
covered with a
chimney of cop-
per, 0; this is
continued by an
iron tube, I,
which passes
through a small
furnace, F. c’ is
another copper
tube connected
with the iron
one. The upper

' Fig.2273.
end of this tube was only one foot in diameter;
it opened into a cowl on the roof. The furnace, F,
was contained in a fire-proof house erected for the
purpose on the roof.
a? This apparatus appears to have been generally only
moderately successful, and in a full House it proved
to be quite inadequate to the purposes intended. Mr.
James Wyatt afterwards made some alterations and
additions, but the whole was destroyed in the fire
of 1834.‘.
Deficient ventilating power, the fault of the above
plan, cannot certainly be charged against the method
adopted by Dr. Reid for ventilating the temporary
House of Commons erected after the fire. Dr. Reid's
arrangements will be understood by referring to Figs.
227 4!, 227 5, which represent a sectional elevation
and ground plan of the buildings, and apparatus
employed. Two or three feet beneath the floor of the
House, a second floor was formed, containing about
20 apertures, each about 18 inches square. Beneath
the second floor was a long passage r; opening into
this, were 2 others of an equal width, r1 and r2 ; in
the passage r1 was placed the warm water pedestal.
Large folding-doors were placed before the entrances,
and within these passages; the temperature of the
house above depended on the relative adjustment with
each other of these folding-doors’. Fresh air, eitherwarm
or cold, according to the season, could be produced,
and changed from warm to cold, or the contrary, as
the variable external temperature of the day or hour
required. The fresh air entered from Old Palace-yard,
through the perforated wall, w. If the folding-doors
Nos. l and 2 were opened, and all the rest closed, the
air entered the passage 1?, passing through the
‘pedestals placed in P1, and warm air only would ‘be
supplied to the House above. If air .moderately
warmed were required, the doors Nos. 3 and a were
opened in addition to Nos. 1 and 2, and two currents,
one cold and the other warm, were then produced,
which met and blended together in the passage 1?, and
then ascended. If air of the external temperature
WARMING AND VENTILATION.
929
only were required, the doors Nos. 3 and a were alone
opened. If required to be only moderately warmed,
Nos. 3 and a were opened, No. 1 half opened, No. 2
closed; the small folding-doors, Nos. 5 and 6, were
then opened, and a slight current of warm air passed
through the small passage p, and mixed with the cold
current entering at 122. The folding-doors in this
passage could likewise be opened when Nos. 3 and a
were closed, and a current of warm air was then con-
veyed to one end of the passage r. The air, whether
warm or cool, ascended through the apertures a a a,
into the space beneath the floor of the house. Imme~
diately over these openings were large platforms,
supported by short feet, the effect of which was to
disperse the great body of air admitted. The air then
entered through small openings made in the actual
floor of the House, about 300,000 in number, each
being about gth of an inch in diameter on the surface


of the floor, but expanding downwards, to prevent their
being stopped with dirt or dust. The sides of the
House under the galleries were battened or brought
forward five or six inches, and in the space thus
formed between the framing and the wall, the air
ascended and passed out through the floors of the
members’ galleries, perforated for the purpose in the
same manner. The floor of the House and galleries
was covered with a thick horse-hair matting with
large meshes, to allow the air to ascend through
them.
The force which set this great body of air in motion
was a ventilating shaft v, 12 feet in diameter at the
base, 8 feet at the summit, and rising 110 feet above
the ground, in which a powerful upward current was
generated by means of a large fire.
In summer, when the air transmitted into the House
was required to be cool, various contrivances were







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1s 1a,,
v r .' . 3:13
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jgi l .3213
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t pr.’ 8
x ‘ID
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sail
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l


I
.1


.., -, I
-~ ":1 if i
1' ‘1 ‘~, i
. .. ,
> .'
I.’
5
9V7 l" 5'- J
saws,
iillllllll ‘flail? its
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Figs. 2274, 2275.


I ‘ ill-l’
wrfimpfjmrgrra 5,; I
0% -
if a 51/ 132

-: ~~ if we
SECTIONAL ELEVATION AND PLAN 01? THE TEMPORARY HOUSE OF COMMONS, WITH DR. REID’S
ARRANGEMENTS FOR VENTILATION- ,_
proposed to be carried on in the chamber immediately
behind the perforated wall w. The air was to be
made to pass into the chamber 1?, over wet surfaces,
so as to be cooled by evaporation, or ice might be
suspended in netting between the piers in the
chamber.
A new ceiling was also constructed a few feet
below the former one, for the purpose of favouring
the transmission of sound. This ceiling was divided
into 3 portions, the central portion being horizontal
from one end to the other; the other 2 compartments
inclined so as to make an angle of 30° with the floor
of the house. These 2 inclined portions were glazed,
but the centre was panelled, so as to assist in the
ventilation of the House. An inclination was given
to the ceiling beneath the members’ galleries, corre-
sponding exactly with that of the lateral compartments
in the newly constructed ceiling above.
The ventilation of the House was accomplished in _
VOL. II.

the following manner z—Each panel of the centre
compartment of the ceiling was raised by blocks several
inches above their styles, thus admitting the air of the
House into the space s, between the two ceilings.
The rapid removal of this vitiated air, and the con-
sequent rushing in of fresh air from below, was effected
by the large shaft v, erected at a distance of about 20
feet from the eastern wall of the building. In this
shaft about 10 feet from the surface of the ground
was a very large coke or coal fire, which produced a
powerful current up the shaft. The space s, between
the two ceilings of the House, opened at the north
end into a large square shaft, which was continued
downwards, and opened underground into the circular
shaft v. T."Vhen therefore the current of hot ascend-
ing air was produced in the circular shaft, there was
a. downward draught through the square shaft, there’
by rapidly withdrawing the air from within the House,
and causing the fresh air to rush into it from openings
3 o
930
WARMING AND VENTILATION.
in the wall w. A damper at d, in the square shaft,
regulated the draught in the shaft v, and consequently,
as it was more or less opened, the supply of air to the
House could be regulated according to the number of
members present.
These extensive and powerful arrangements certainly
had the effect of rapidly changing the air of the house,
and furnished the means of regulating the amount of
ventilation. One objection to them was the large
quantity of space required for the apparatus, &c.
Another objection was, that the fresh air drawn up
through the hair-cloth carpet which covered the per-
forated floor was charged with particles of ground
dust or mud from the members’ feet, and this being
carried up entered their eyes, nostrils and mouths,
and even found its way into their lungs.
Many years ago- a clever plan
was contrived by the Marquis of
Ohabannes for ventilating Oovent
Garden Theatre. In this case the
large central chandelier g, Fig.
2276, was used as the ventilating
force. Over this was placed a
funnel of wrought-iron z’, for carry-
ing the- foul air into a wooden
shaft war, which ascended from
the ceiling to the roof, and was
surmounted by a cowl c. The
hot air at the level of the ceiling
found its way into this shaft, and
into it also were conducted pipes
aw from different parts of the
house for carryingoff the foul air.
A furnace was placed in one of the
galleries, and it was fed by the
vitiated air from several tiers of
Fig. 2276. boxes. A similar furnace was
placed over the stage, and the gas chandelier venti-
lated the centre.
M1211. Brown of Manchester has proposed to ven-
tilate the rooms of an ordinary dwelling-house in
which gas is used for illuminating, by means of the
heat thereof. Through an opening in the ceiling is
passed a wide tube, one end of which conveys the foul
air to the outside of the house, and the other projects
a little below the level of the ceiling. The gas-pipe
enters on one side, and is bent so as to hang perpen-
dicularly in the centre of the tube, and carries an
annular burner at the lower extremity. The burner
is surrounded by a glass chimney, which is supported
at its top on a metal cone-piece, and secured to the
lower extremity of the tube by screws.
this arrangement is surrounded by a hemispherical
glass shade, the mouth of which is uppermost, and‘ its
upper edge is a few inches below the level of the
ceiling. The shade is attached at its upper edge‘ by
screws to a metal ring, and is hinged to a second ring
fixed to the ventilating tube by radial arms.‘ _ This
outer shade can be lowered by means of a cord, 'for
the purpose of lighting or cleaning. A highly
polished metal reflector is also added to increase the
effect of the light. The air of the apartment passes


Ohdvglad
The whole of '

off in the strong draught occasioned by the burner,
and a fresh supply of air is admitted at the lower
part of the room.
Dr. Faraday’s method of ventilating gas-burners,
that is, of carrying off the products of combustion
without allowing them to contaminate the air of the
room, is noticed under Gas. I-Iis method of venti-
lating lighthouses requires a brief notice in this
place.
In an ordinary lighthouse fittpd up under the
dioptric system [see LIeH'rHoUsn], from 12 to 14:
pints of oil are consumed per hour, and under the
catoptric system, from 15 to 20 pints within the same
period. Oil contains 78 per cent. of carbon, 11'5
of hydrogen, and 105 of oxygen; hence the products
of combustion consist chiefly of water and carbonic
acid. The hydrogen contained in llb. of oil is sufli~
cient in combination with the oxygen of the air to
produce rather more than 11b. of water; in like
manner, the carbon in Ilb. of oil will by its com-
bustion produce 2,8,“, the lbs. of carbonic acid, to
form which not less than 13% lbs. or 172% cubic feet
of air are spoiled by being entirely deprived of oxygen.
In the Tynemouth lighthouse, 195% ths pints of oil
were consumed per hour, producing a quantity of
vapour of water equal to 20 fluid pints, which vapour
is condensed by the glass of the lighthouse lantern,
which is kept constantly cool by exposure to the
weather, and in very cold weather the water thus
condensed is frozen into a crust of ice varying from
~41— to a an inch in thickness in one night. If this
ice were quite transparent it would distort the light
and render it dim, but the vapour which produces it
is charged with minute particles ‘of soot,'which be-
come entangled with the ice, and produce further
opacity. The clearing away of this ice every morning
.was a work of‘ great labour to the men, and of
danger to the glass; while the large quantity of car-
bonic acid generated rendered the lighthouse un-
healthy, if not positively dangerous to the occupants.
Under the dioptric system, the remedy was easy.
All that was necessary, was to lengthen the chimney
of the single central lamp, or rather to place over the
glass chimney'a tube of sheet-iron, carrying it through
the roof of the lantern into the open air, the upper
extremity of the tube being furnished with some kind
of cowl or louvre. Under the catoptric system, where
there are a number of lamps with reflectors, a central
ventilating shaft was also formed, and over the glass
chimney of each lamp was placed one extremity of a
small tube, this tube being curved so that the other
extremity opened into the central shaft. The tubes
were supported by the frame which carried the lamps
and reflectors, and as the ‘frame revolved, the upper
ends of the tubes described each a small circle within
the central chimney, but without touching it. In this
way the small tubes carried off the products of com-
bustion without interfering with the reflectors. This
method of ventilating succeeded under both systems
of lighting, as was proved by the interior of the
lantern remaining dry and healthy, and the windows
bright. The plan is described by Dr. Faraday as an
WARMING‘ AND VENTILATION.
931
adaptation of sewerage to the atmosphere, aerial sewers
being employed to carry off the refuse of the spoiled
air, instead of allowing it to accumulate in the house
or apartment.
For the ventilation of collieries and mines, see
COAL—MINE, MINING. '
Ventilation (23/ Mechanical Contrz'vmzcea—In the
course of the last century, two men who have ren-
dered good service to science attracted considerable
attention to their inventions for the purpose of
ventilating ships. These inventions were Hales’s
Ventilator and Derry/alters’ Fan. The former con-
sisted of 2 outer cases, each 10 feet long, 4;}; feet
wide, and 13 inches deep inside, with a wooden
midrif or valve fixed at one end to each case by iron
hinges, and moving up and down by means of a lever
12 feet long. A number of valves fixed in the outer
case, and hinged so as to open inwards, admitted the
air to the interior, which air was again expelled at
each rise and fall of the midrif through another set
of valves, which were hung so as to open outwards.
The emission valves were covered by a box with a
large aperture, from which the air was conveyed by a
pipe into any part of the ship that was to be venti-
lated. Thus this machine, in its construction and
action, resembled a pair of bellows of a clumsy kind.
Two men were required to work each lever, and thus
to put in action an apparatus which was termed by
the inventor the “Ship’s Lungs.” In working this
ventilator, the labour was obvious, but the benefit
conferred was not so apparent; for it is diliicult to
persuade men that respired air can be foul, when the
impurities are not visible to the eye.
Although Dr. Desaguliers’ fan shared no better
fate on board ship than Dr. Hales’s ventilators, it
was nevertheless an invention of great practical value,
and has continued in use up to the present time.
WVhen placed within a ventilating shaft, and made to
rotate by the descent of a weight or other mechanical
means, it becomes a ventilator of considerable efficacy.
The fan, as originally invented in 17 34, was worked
by hand. It consisted of a wheel, which was 7 feet
in diameter, and 1 foot wide, and had 12 radii or par-
titions, approaching within 9 inches of the axis, leav~
ing a circular opening 18 inches in diameter. This
wheel was enclosed in a concentric case, furnished
with a blowing-pipe on the upper part, and a suction-
pipe communicating with the central opening in the
wheel, which was turned by a handle attached to the
axis, which passed through the case, and rested on a
standard. The fanner was made so as to revolve
easily, but as closely to the concentric casing as pos-
sible, without any communication with the air, except
through the suction and blowing pipes. To. ensure
this, rings. of blanketing were fixed within the case, so
that the edges of the vanes might be in contact
therewith, and the air have no other escape than
by the blowing-pipe. By the revolution of the
wheel, the air within the case was rapidly impelled
by centrifugal force to the circumference, where it
was condensed, whirled round, and forced out, in a
powerful current, through the opening of the blowing—

pipe, while the partial vacuum thus formed set a
curHrent of air inimotion towards the centre, which
current entering thereat, and passing upwards, was
distributed between the vanes, and, being driven to
the circumference, passed out in a powerful con~
tinuous blast. The suction-pipe could be made to
communicate with the external air by means of a
pipe, or with a space containing heated air; and the
blowing-pipe could be connected with a room, which
could thus be filled with cool fresh air, or with
warmed air, the quantity being regulated by the
speed of the wheel. If foul air had to be drawn
out, the suction~pipe was connected with the space
containing it, and the blowing-pipe with the exter-
nal air.
In the year 17 36, a wheel of this description was
erected over the ceiling of the House of Commons,
for the purpose of drawing out the vitiated air, in the
manner just described, a'man being kept constantly
at work, during the sitting of the House, to turn the
wheel. It was stated, that this wheel was “able to
suck out the foul air, or throw in fresh, or do both at
once, according as the Speaker is pleased to command
it, whose order the ventilator waits to receive every
day of the session.” This apparatus continued to be
used for ventilating the House until the year 1791,
when the chief clerk of the House, Mr. Holland, pro-
posed its removal from the room over his own private
apartments, to the centre of the roof immediately over
the House, as being a more advantageous position.
This was accordingly done, and continued in opera-
tion until 1817, when a similar contrivance was
recommended for the ventilation of the House of
Lords. It was not, however, erected; for, in 1820,
the whole business of warming and ventilating both
Houses was entrusted to the Marquis of Chabannes,
whose plan has already been noticed.
In some of the large factories in Manchester and
elsewhere, the fan is employed for extracting the foul
air in measurable quantities. It is made to revolve
at the rate of 100 feet per second. One of Messrs.
Fairbairn and Lillie’s excentric fans, placed at one
end of an apartment about 200 feet long, when in
full action throws the air so powerfully out of it, as
to create a draught at the other end of the room
capable of keeping a weighted door 6 inches ajar.
When connected in the attics with a horizontal pipe,
into which vertical tunnels from each room are
inserted, it draws out the air so rapidly from them
as to cause a breeze from every part of the adjoining
floors, thus producing an excess of ventilation in the
apartments. The simple and cheap contrivance of cast-
iron boxes, placed on every story in communication
with the fan, is the method adopted. A side and afront
view of the fan are given in Figs. 2277, 2278, such
as has been used of late years for ventilating factories,
for removing through tunnels the dust disengaged in
cleaning fibrous materials, such as cotton, hemp, &c.,
for blowing air into forge fires, and many other similar
purposes. It consists of two cast-iron end plates, I I,
with a central opening, 0 0, from the circumference of
which the outline of each plate enlarges spirally, the
3 o 2
932
WARMING AND VENTILATION.


point nearest the centre being near 2:, and that furthest
off being under the lower vane, v. This pair of parallel
plates is connected by bolts, 6 b, a mantle of sheet-
iron being previously inserted into grooves cast in the
edges of the end plates, so as to enclose a cavity with
an elongated outlet at A, to which a pipe is attached
for carrying off the air in any direction. Within this





Fig. 2277.
cavity a shaft, 3, revolves in bearings, a a, placed
Fig. 2278.
centrally in the frame-plates, I I. On this shaft, a
boss is wedged fast, bearing 5 flat arms, 22 v, to which
are riveted 5 flat- plates, or wires of the shapes shown
between I and I in Fig. 2277, having a semicircular
piece cut out of them on each side, about the size of
the end opening. On one side of the shaft, 5, beyond
the box—bearing, the fast and loose pulleys, P, are
fitted for receiving the driving band, and for turning
the wings in the direction shown by the arrow.
Thus the air is driven before them out of the end
orifice, A, while it enters by the side openings at o 0.
By the centrifugal force of the revolving wings, the
air is condensed towards their extremities, and makes
its escape from the pressure through the orifice, A,
while it is continually drawn in at the sides by its
tendency to restore the equilibrium. The fans are
sometimes constructed so as to have their mantles
concentric with their central shafts, as in Dr. Desa-
guliers’ fan. The improved fan (Fig. 2278) is called
the excentric; the air which escapes through the out—
let, A, has undergone compression during its whole
progress through the spiral space with the revolving
wings, and is equal in density to that compressed at
their extremities by the centrifugal force. The fan,
therefore, discharges considerably more air than that
with a chamber concentric with its wings, because, in
the concentric fan, there is considerable loss of power,
on account of a large quantity of air being carried
round by the leaves of the fan, instead of passing out
through the discharge-pipe at the circumference; but
in the excentric fan, each wing or leaf, in passing the
point :0, acts as a valve to cut off the entrance of the
uncondensed air, which would cause an eddy, and
retard the proper current by the inertia of its par-
ticles. When the fan is required to draw air out of
a series of independent rooms, it has its circular side
openings, 0 0, enclosed within caps, which are con-
nected with pipes communicating with such rooms.
Slide or throstle valves may be placed in the ex-
hausting, as /well as the condensing pipes, for
regulating the distribution of the rarefying or blowing
power.1 ‘
\
(ll “ Philosophy 'of Manufactures.” London, 1835.

The fan produces its greatest effect 'when the
extreme points of its leaves move through about
80 feet per second. The mean velocity of that
portion of the vanes by which the air is discharged,
is about 7 -8ths of the velocity of the extremities ; but,
owing to the inertia of the air, there will be a loss in
the velocity of the issuing current, which will increase
with the increased speed of the vanes; so that, in
general, the current will be discharged with a velocity
equal to about 3-4tths of the velocity of the extre-
mities. This velocity, measured in feet per second,
multiplied by the area of the discharge-pipe in square
feet, will give the number of cubic feet of air dis-
charged per second. _If the effective velocity of the
vanes be 70 feet per second, and the sectional area of
the discharge-tube be 3 square feet, then 70><3=210
cubic feet of air discharged per second, or 12,600
cubic feet per minute. As a cubic foot of air weighs
527 grains, there will be about 13 cubic feet of air to
m01>§60=969 lbs. weight of air
set in motion per minute, with a velocity of 70 feet
per second. The height from which a heavy body
must fall in order to acquire a velocity of 70 feet per
second is 7 6'5 feet, which, multiplied by the number
of pounds weight moved per minute, will give the
power necessary to discharge this quantity of air at
the stated velocity; and this product divided by
33,000 (the number of pounds weight that one
horse will raise one foot high per minute) will give
the amount of steam-power required. Therefore
“763258339 : 2'24, or nearly 2% horses’ power, will be
required to discharge the given quantity of air at the
velocity stated.2
A more powerful fan than the above has lately been
introduced, under the name of Cfiaplz'rz’s Duplea:
Pressure Fan. It consists of 2 fans combined in 1,
(Fig. 2279,) with a single spindle driven by a central
band—pulley. The air is
taken in by one case, in
the direction of the arrow,
and conveyed in its com-
pressed state into the, se-
cond, whence it is dis-
charged at a. much higher
pressure than can be pro-
duced by a single fan. The
case in which the air is first received is the larger. Fig- 2279-
of the two; and the second case, which contains a
smaller fan than the first, subjects the air to a second
compression. '
In some contrivances, the spokes or vanes are
arranged in the form of a screw, in which case, an
ascending current of vitiated air will impart motion
to it by acting on its spirals. This machine is very
inferior to the fan in ventilating effect, for as soon as
the condensation of the air between the spirals be-
comes equal to the friction between the air and the sur-
face of the spirals, no further increase in the amount
(2) Ure, “ Philosophical Transactions.”

a pound ; therefore


WARMING AND VENTILATION".
933
of discharge takes“ place. The screw‘ will only dis-
charge small quantities of air at a moderate velocity,
so that it is not adapted to an extensive scheme of
ventilation.
The pun/rah, so valuable in warm climates, is a ma-
chine which acts somewhat like a lady’s fan, keeping
the air of the apartment in motion, but not contribut~
ing in any way to bring in a fresh supply, or to dis—
charge that which is vitiated. The punkah is a large
broad surface of almost any material, suspended in
the centre of the apartment, above a bed or table,
with a line attached to one side, and passing out of
the apartment through the wall to an attendant on the
outside, who gives motion to the extended surface.
Some years ago, a small steam-engine was procured
from England by the Nabob of Oude, to work the
punkahs of his palace. I
Among the ancient Egyptians, there was a mode of
spontaneous ventilation called the mulguf or wind-
conductor. This is still in use in modern Egypt, and
consists of a frame erected at the top of the house,
and covered in on all sides, except in the direction of
the prevailing winds. The top or roof of this ma-
chine slopes inwards from the open ends to the centre,
where a partition deflects the wind downwards to the
apartments. The modern revolving cowl is some-
times made to act in a similar manner.
SECTION IIL—ON THE WAniIINe AND VENTILATION
or BUILDINGS.
In an enclosed space, or collection of enclosed
spaces, such as a dwelling-house, causes are always in
operation which tend to rarefy the internal air, and to
set in motion currents from the outside to the inside.
The presence of a human being in a room is in itself
suflicient for this purpose; but it is powerfully in-
creased by the combustion of lamps, candles, and fuel.
If proper ventilating openings be made at the highest
point in each room, an upward current will in most
cases be established, or such a current may be deter-
mined by the introduction of a gas-flame, or of a small
coil of pipe, where the building is warmed by hot
water, or of a fan set in motion therein by means of a
descending weight, which requires to be wound up
only once in about 2d hours.
The arrangements in Sir John Robinson’s house at
Edinburgh are often referred to as a model for the
application of sanitary arra 'gements; the system of
ventilation is said to be so 1ierfect, that “ while the
mass of air in the rooms and passages is constantly
undergoing renewal by the escape of the vitiated air
above and the admission of large supplies of fresh air
from below, no currents are perceived in the apart-
ments, which even when crowded with company and
amply lighted preserve a remarkable freshness of at-
mosphere.” The sectional area of the cold air pas-
sages is about 141 square feet, and they are left open
in the coldest weather, provided there is not much
wind. The air passages are formed of cylindrical
fines of earthenware, 9 inches in diameter, built into
the gables, close to the smoke-fines. The lower ends
of the ventilating flues open into spaces between the

ceilings of’ the respective rooms and the floors above;
and one or more exit air~flues is provided for each
room. The hot, vitiated air passes up through the
ceilings by a continuous opening of about 1% inch in
width, behind one of the fillets of the cornice, all
round the rooms, and, having passed into the space
between the ceiling and the floor above, it ascends by
the fines in the wall, and is discharged into the va-
cant space between the attic ceilings and the roof,
and thence through the slates to the open air. This
last part seems to be a defect in an otherwise ex~
[11:10
[3:30 \ DIIIEJ \\
\
i
[I

Fig. 2280. WARMING AND VENTILATING ARRANGEMENTS IN
SIR Jorm nomNsoN’s noose.
cellent arrangement; if the joints of the slated roof
do not afford a snfiicient exit for the hot, vitiated air,
there will be a resistance, and consequent cooling or
condensation by the cold surfaces of the slates, ex-
posed as they are to the direct action of the outer
air. A turret or louvre seems to be wanting on the
roof. The passage for the hot air through the cor-
nice is not visible from the floor of any of the rooms.
The air-fines terminate above the ceilings of the attics,
and below the roof,’ to prevent smoke being carried
down them by reverse currents. The supply of fresh
93st
WARMING AND VENTILATION.
air to the house is from a garden behind; it is con-
veyed by a passage 0, Fig. 2280, which has a sectional
area of 8 square feet. There is also a similar passage
in front of the house. he air thus admitted is
warmed by a cookie to from 649 to 7 0°. In very cold
Weather, '7 0° is preferred, to allow for the cooling
effect of the walls and windows, and thus to main-
tain a constant temperature of 60° throughout the
house. The air. thus warmed is discharged into the
well 20 0 of the staircase, from which the rooms draw
the supply required for maintaining the upward cur-
rents in the chimneys, and in the ventilating flues.
The air from the well gets into the apartments by
means of masked passages, 41 or 5 inches wide, and
{t feet long, overt‘ the doors, and by openings about
1 inch in widtln under each door. The sectional areas
of these passages are more thanequal to the areas of
the chimney andr ventilating flues, so that as the air
within is not much rarefied, there is but little ten-
dency in the outer air to‘ enter at window chinks, and
other apertures.. rl‘he course of the air from the large
aperture 0 overtlie' stove, through the staircase, over
and under the doors, into the rooms, and thence
through the ceilings, andl upwards by the escape—fines,
is shown by tlie'direction of the arrows : the quantity
of escape is regulated by means of throttle-valves at
the mouth of each ‘escape-flue, by which the rate of
the ventilatingcurrent can be increased or diminished.
The kitchen i's-ventilated in a similar manner. One
flue proceeds from the ceiling over the fireplace, and
another from over the‘ gas cooking-stoves. The first
flue is built in the gable close to the smoke flue, and
the second passes upwards by the back of the cistern
and pipes of a Watercloset, thus protecting them from
the action of frost. p' is the pipe conveying the
smoke from tlie'fire which heats the cockle into the
smoke-fluef At d is a damper for regulating the
draught of thisfire.
In the above- arrangement, the cockle-stove was
used as the source of heat. There are many cases in
which the Arnott stove' may be used as a means of
warming and ventilating, when placed in one of the
lowest roomsiof 'the house, and used as a source of
heat to the airsupplied‘ to the house from without, as
in the following ingenious application of it by Mr.
Charles Oowperl; In a‘ letter to the editor he says :—
“ I tried anl experiment this winter, and derived
considerable advantage from it, for the water in the
jugs in the top =rooms of myhouse did not once freeze,
notwithstanding the intense cold. My house consists
of four floors of
two rooms each,
with a wash-
house outside at

fa“
but little used,
-> D
Fig‘ 2281' nott stoves, 1A
_ <\ the back. The
; back kitchen is
so I put one of
the smallest Ar-
inches square,.in it; applying a sheet-iron plate to
close up the chimney _of the kitchen rcngc. This
'should be apertures from the stair~

heated the staircase a little way, but the heat could
only get up by means of an upward current under the
flight of stairs, and a downward current on the stairs,
as shown in Fig. 2281. I found that in all states of
the wind, there was a strong inward current of air at
a door opening into the outer air from the back
kitchen. There were also inward currents of air even
at the top windows of the house. I believe this is
the case in nine houses out of ten, although the house
being warmer than the outside, the air ought to enter
at bottom, and escape at top. This shows that there
is no proper entrance provided for the air, and conse-
quently it is no wonder that we have smoky chimneys.
I therefore had a zinc pipe, 5 inches diameter, A, Fig.







--. 4i-
..F ii
[1%
2282, brought through the wall, and directedzagainst
the side of the stove, to which I fitted a piece of sheet-
iron, so that all the air entering at the pipe might be
forced to spread itself over the exterior of the stove.
I have a damper in the pipe, but it is left full open
when the stove is in use. I have thus a 5-inch
column of- air. always pouring into the house, and
heated to a comfortable temperature by the stove.
This has much diminished the tendency of the fires
to smoke, although there is still sometimes a down
draught in the mused chimneys. The chimneys in
regular use never smoke now. I consider it quite suc-
cessful as far as it goes; but it would be much better
with a larger stove and a larger pipe. I had nothing
to guide me as regards the size of the pipe, except a
few experiments by opening the back door 31,-, 31;, and
71— inch, and noting the effect, and the area of passage
thus produced. In the coldest weather, the pipe
admitted about as much air as the stove could take
the chill off. If I were going to do it again, I should
make the case to surround as much of the stove as
possible, and make the pipe A much larger, say
10 inches, or with a larger stove 12 inches. I think
it is the right principle to have a
large-free opening for air at the bot-
tom of the house. Tl‘is would stop
the cold draughts in at windows,
and prevent down draughts in fines
and smoky chimneys. The air thus
entering must have the chill taken
off it, say 50° or 60°; and there






W
m
~\~'$\


MIHRW
case (which is the air main) into the
different rooms, that is, if the leak-
age round the doors is'not enough.
Perhaps the best plan would be, Fig- 2233'
holes through the top of the door, (as in Fig. 2283,)
with a shield to throw the air up if desired.‘ If a


haw "
_WARMING AND VENTILATION.
935
room be supplied with air at 50°, a very small fire in
the room will serve for comfort, and for carryingiofi
the foul air. It might perhaps be thought that the
warm air would all go up to the top of the house,
but .I find that the staircase is very considerably
cooler at the upper part, and gets gradually warmer
and warmer in descending from the top to the bottom.
I have no doubt that a larger entrance-pipe for the
air would send the heat up higher, but I have no fear
of too much heat going to the top. With my 5-inch
pipe, I have still both ascending and descending cur-
rentson the staircase, and I think this will always
bethe case.
. . “I had a good deal of trouble at first by the pro-
ducts of combustion from the stove coming back into
the room round the iron plate, which was not built in.
I found that this was owing to the flue of a copper
in the washhouse entering the same chimney near the
bottom, so that the air blew through the copper-flues,
and down the chimney into the room. I made a
wooden stopper covered with canvas, to fit the front
of the copper-furnace, which effectually cured this
defect.”
Mr. William Griffin’s cottager’s stove appears to be
judiciously arranged for the purposes of warming and
ventilating. Fig. 228% is an external elevation, and
Fig. 2285 a vertical section. It is fitted with 2 ovens,
or an oven and a hot-
closet. “ It com-
prises an open fire—
place in the centre;
a draw-shelf at the
bottom of the grate;
a drop-shelf at the
top, which when
raised, forms a
blower 5 a hot-plate
forming an -ironing-
stove; an opening at
the top for the emis-
sion of warm air ;
an oven, hot-closet,
damper, and sweep-

Fig. 2284.










\\\ \\ .
\~.\\\. \ .
door, and a bOllBl.
N In the flange of the
\\ Q, oven and closet are


slide-doors for the
_ purpose of admitting
" a brush when sweep-
ing is required.”
The oven has a flue
all round it, and
is equally heated.
“When cooking is
over, a fire made up
of small coals, cin-
ders, and ashes, well
saturated with water,
will last for several hours. The room is made agree-
ably warm by a continual supply of pure warm air
drawn in from without through a drain or pipe to the
hot-air chambers at the back and side of the fire-


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l place, and emitted at the aperture at the top of the
stove.”
In an interesting pamphlet by Mr. Francis Lloyd,
recently published,1 is described a warming and venti-
lating stove,_ constructed on the principle of the
Polignac Stove (Figs.2289——224¢3). In order to pre-
vent the chimney from smoking, and at the same time
to prevent drauglits from doors and windows, Mr.
Lloyd’s first idea was to carry an air-tube from
the external walls to the hearth-plate, to supply the
fire with the air required for the combustion of the
fuel. But as such a soufiict would interfere with the
circulation of air in the room, it was proposed to
construct caliducts also. “ On examination, an ordi—
nary register-stove showed that but a small proportion
of the whole space allotted to it was occupied by the
fire-grate, the frame around and above the grate form-
ing a mere ornamental facing. There seemed to be
no obstacle to substituting for this mere shell of cast—
iron a horizontal and two upright tubes; and if they
were connected with that beneath the hearth-plate, a
continuous tube would be formed around the front of
the fire. Air passing through these tubes would, it
was imagined, acquire some warmth. The next con—
sideration was, how to provide for the admission of
the fresh air thus warmed into the room: and here it
was important to select a place where the inflowing
current should not be felt. The upper part of the
mantel, from its proximity to the stove, and its position
relatively to the occupants of the room, seemed a suit-
able place for the ingress of the air. Supposing the
upper horizontal tube to have an opening or slit
extending along the top throughout its whole length,
the stove to be set sufliciently forward to leave this
slit beyond the line of the chimney-breast, and the
upper mantel and mantel-shelf to be so formed as to
continue the passage-way from the tube, the air would
be discharged into the room at about etfeet above the
level of the floor.” This plan was adopted with suc-
cess in the room of a house in town. A second and
still more successful experiment is thus described by
the author :—-~
“ The dining-room of a house, a few miles from
town, was rendered scarcely inhabitable in conse-
quence of the chimney smoking. The room (which
was about 16 feet square and 8 feet high) was on
the ground-floor, with no basement story beneath.
It was a few inches below the level of the garden in
front, and had a provision for the circulation of air
beneath the floor. The house was old, with doors
and windows fitting but indiiferently. The stove
was of modern make; but the fire invariably burnt
dull, and the room was scarcely ever well warmed.
As the room was required for daily use by the family,
alterations to the old stove would have caused incon-
venience; a new register—stove, of the ordinary
dining-room kind, was therefore selected, with the
view of trying how such an one could be fitted with
air—tubes. The plan of the new stove is shown in

(1) “ Practical Remarks on the Warming, Ventilation, and
Humidity of Rooms.” 3vo. London, 1854
936
WARMING AND VENTILATION.
Fig. 2286. To the cheeks and the back of the face,
a a, of the stove were riveted two strips of sheet-iron
bent in the form shown in Fig. 2287. The plan then
appeared as in Fig. 2288. Two side-chambers or
Fig. 2286. Fig. 2287. Fag. 2288.
tubes, {2 6, being thus obtained, the back of the upper
face of the stove was fitted with a rectangular tube,
also of sheet-iron, which was connected with the two
side tubes, making uninterrupted communication
between them. The old stove was set very far
back in the chimney shaft, and was fitted with a
large marble mantel, the displacement or altering of
which was, on many accounts, objectionable; it was
therefore determined, in this instance, to admit the
air into the room immediately under the mantelpiece,
and afterwards to adopt means for preventing any
inconvenient rush of air in a horizontal line into the
room. The area of a section of each of the side tubes
exceeded 18 inches, while that of the horizontal tube
was about 4.0 inches. The width of the face of the
stove was 3 feet; and to furnish the means for the
admission of the air into the room, an opening of 1
inch in width was left at the top of the horizontal
tube, in its vertical face, extending its whole length.
A hearth-plate of cast-iron was then provided with
openings corresponding to the horizontal section of
the side tubes, as shown in the plan. The hearth-
plate was then set with a chamber beneath, extending
in the middle as far back as the line of the front fire-
bars. From this chamber a zinc tube, 6 inches square,
was carried under the marble hearth, beneath the
floor, through the front wall into the garden, where
it was carried up to the height of 14.‘ inches, and was
furnished with a cap having sides of finely perforated
zinc. A passage-way of 36 inches area was thus
obtained beneath, around, and above the from! part of
the stove, while there was a corresponding ingress
for the air from the garden, and egress from the upper
part of the stove into the room. The stove was set
in the ordinary manner; and, within 241 hours of the
removal of the old stove, a fire was lighted in the new
one, and the room was in occupation. It was at once
evident that the tendency to smoke was remedied,
and the fire burnt freely and cheerfully. As it was
felt to be an important point to introduce the air into
the room in such a direction that its entrance should
not be perceptible, the air-opening was furnished with
a metal plate bent in such a ‘form as would direct the
air-stream towards the ceiling, and also admit of the
supply being diminished, or stopped entirely, as might
be found desirable. The complete and agreeable
change in the character of the air of the room was at
once apparent to every one; and, instead of the room
being barely habitable, in cold weather it was found
to be the most comfortable in the house. This stove
was fixed at the latter end of December, 1850, and
has been in use for four Winters without the slightest
difficulty of management, and with entire satisfaction
to the inmates of the house. During the first winter,

careful observations were made on its action, and the
results are in many respects remarkable. Within an
hour after the fire is lighted, the air issuing from the
air-passages is found to be raised to a comfortable
temperature; and it soon attains a heat of 80°, at
which it can be maintained during the day with a
moderate fire. The highest temperature that has
been attained has been 95°, whilst the lowest on cold
days, with only a small fire, has been 7 0°. The result
of twenty observations gave the following tempera-
tures :—-On two occasions, the temperature was 95° ;
the fire was large, and the door of the room was left
open, so that the draught through the air-tubes was
diminished; on five occasions, the temperature was
below 80°, averaging 75° ; the remaining thirteen gave
an average of 80°. . The mean temperature of the
room at the level of respiration was 61°, while the
uniformity was so perfect, that thermometers hanging
on the three sides of the room rarely exhibited a
greater difference than 1°, although two of the sides
were external walls. As might be expected, there
was no sensible draught from the door and window.
On observing the relative temperatures of the inflow-
ing and general air of the room, it appeared that there
must be a regular current from the ceiling down to
the lower part of the room, and thence to the fire.
The inflowing current, being of a temperature nearly
approximating to that of the body, was not easily de-
tected by the hand; but, on being tried by the flame
of a candle, it was observed to be very rapid, and to
pursue a course nearly perpendicular towards the top
of the room, widening as it ascended. It was also
noticed, that the odour of dinner was imperceptible
in a remarkably short time after the meal was con-
cluded. In order to trace the course of the air with
some exactitude, various expedients were made use of.
It was felt to be a matter of great interest to
ascertain, if possible, the direction of air respired by
the lungs. The smoke of a cigar as discharged from
the month has probably a temperature about the same
as respired air, higher rather than lower, and was
therefore assumed to be a satisfactory indicator. On
its being repeatedly tried, it was observed that the
smoke did not ascend to any great height in the
room, but tended to form itself into a filmy cloud, at
about 3 feet above the floor, at which level it main-
tained itself steadily, while it was gently wafted
along the room to the fireplace. In order to get
an abundant supply of visible smoke of a moderate
temperature, a fumigator, charged with cut brown
paper, was used. By this means a dense volume of
smoke was obtained in a few seconds; and it con-
ducted itself as in the last-mentioned experiment. vOn
discharging smoke into the inflowz'vzg air-current, it was
diffused so rapidly that its course could not be traced,
but in a short time no smoke was observable in the
room. Another experiment was made with a small
balloon, charged with carburetted hydrogen gas, and
balanced to the specific gravity of the air. On setting
it at liberty near the air—opening, it was borne rapidly
to the ceiling, near which it floated to one of the sides
of the room, according to the part of the current in
WARMING AND VENTILATION. 987
which it was setnfree; it “then ,inraliiahlxdeacendvd
slowly, and made its way with a gentle motion
towards the fire. The air has always felt fresh and
agreeable, however many continuous hours the room
may have been occupied, or however numerous the
occupants. It is diificult to estimate the velocity of
the infiowing current ; but if it be assumed to be 10
feet per second, there would pass through the air-
tubes in 12 minutes as much air as will equal the
contents of the room. And as it appears that the
air so admitted passes from the room in a continuous
horizontal stream, carrying with it up the chimney
the rarefied air, the exhalations from the persons pre-
sent, the vitiated air from’ the lamps or candles, and all
vapours rising from the table, it is by no means sur-
prising that the air should always be refreshing and
healthful. Since this stove has ‘been fixed, others
have elsewhere been fitted up on the same principle,
and have been found to exhibit similar satisfactory
results.”
Figs. 2289, 2290 represent a horizontal and a ver-
tical section of the tubular stove, in which a is a flue
\~‘
4

— . i ‘yr’, f / ‘7",. -.
p2 ¢
3'1
£1
5


Fig. 22s9.
6 X 9 inches, for con-
ducting the external air
from the outer wall to
the under side of the
hearth-plate 6 ,- 00 are
openings in the hearth-
plate ‘.6, communica-
ting with two upright
tubes of similar form,
which conduct the air
entering at a upwards
to the horizontal
tube (Z. This tube
is fitted to the two
upright tubes, and has
an opening extending
along its whole length.
- If the width of the
stove be 3 feet, this
opening should be 1%,;
inch wide. The stove should be set 1% inch forward
from the chimney-breast ; f is the upper mantel,
standing forward from the chimney-breast e 1% inch ;
g is the mantelshelf, with a portion of the back next
the chimney-breast cut away in order to continue the
air—passage; 71 is a thin slab of marble, % inch deep,
built into the chimney-breast, and extending to the
width of the mantel; it serves as a support for a
chimney glass, and also to divert the current of air
from flowing directly up the chimney-breast ; dis a

Fig. 2290.

strip of metal or marble, which serves to guide the
air-stream upwards. By moving 2' to it, the supply ofv
air may be regulated ; or i may be fixed, and a thin
strip of metal fixed on centres at the‘ extremities be
placed between 2' and it, so as to act like a throttle-
valve. The opening between 2' and it need not be
more than 1 inch. ‘
Mr. Lloyd also describes a domestic grate, which
consumes its own smoke. It is~circular in form,
consisting of 41 circles (17 inches diameter) of bars,
separated by pins, and fastened to an iron cross,
which has a hole in the centre to admit a vertical
spindle, to which the grate is firmly secured by means
of keys above and below the cross. There is a hollow
cylinder of iron or fire-clay, (5 inches diameter,) with
a hemispherical top having a slit in it. This cylinder
rests on the cross, and is as high as the top bar. The
remaining part of the cross supports the usual grating
for a stove, giving an area of 200 circular inches.
There is an iron bar about 2 feet 6 inches long, with
a coupling to embrace the spindle immediately below
the fire-grate; also an iron hearth—plate, having a
hollow boss to receive the end of the spindle. In
setting the stove, the hearth-plate was so placed that
the centre of the boss was 18% inches from the back
wall. Brickwork was then carried up to the height
of 1 foot 6 inches, and a depth of 13}; inches, except
in the centre, where a semicircle of 9 inches depth
was formed, thereby making a niche of 18 inches in
width. This was covered with a Welsh-lump, upon
which brickwork was carried up square 2 feet 6 inches,
and then sloped off to the chimney back. The end of
the spindle was then placed in the boss, on the hearth-
plate, and the iron bar secured in the brickwork. The
coupling being secured, the circular grate now appeared
one-half in the recess, the other projecting beyond the
brickwork at the back, the Welsh—lump being about
half-an-inch from the top, with its edge over the centre
of the grate. The fire being lighted, and got up well
in the whole circle of the grate, fresh coals were put
on the front half, and the grate was turned half—round
on its axis. A clear bright fire then appeared in
front, while the gases and smoke from the fresh coals
at the back made their way forward to the edge of the
Welsh-lump, where they were subject to the heat of
the clear front fire, aided by the stream of air passing
up the hollow cylinder, which air, as it escaped by the
slit, inixed with the smoke and gases, and assisted
their combustion. When the front fire was burnt
low, fresh fuel was put on, and the grate again turned
half round. The fuel which had been at the back was
then found to be coked, or to be giving off only a
clear bright flame, according to the time that had
elapsed since the fuel had been put on. On turning
the stove round, so as to have the fresh fuel alter-
nately at the back and front, it was evident that the
arrangement secured the combustion of a large pro-
portion of the smoke. This desirable end, therefore,
is accomplished by the very simple operation of turn~
ing the grate half round, whenever any fresh fuel is
put on. A clear, cheerful fire, with a semicircular
face, well adapted to the radiation of heat, is thus
938
WARMING AND VENTILATION-—WATOH.
always presented to the room. For cottage use there
would require to be some appendages to the bar, for
the reception of trivets, kettles, and saucepans. These
appendages would be placed over, but still be inde-
pendent of the fire—grate. The arrangement also
ensures the having at all times a clear bright fire,
adapted to broiling or roasting.”
Many years ago, Mr. Cutler invented a smoke-
consuming grate, the principle of which was to supply
the fuel at the bottom, so that the volatile portions,
passing up through the incandescent fuel, were con-
sumed. The mechanical arrangements of this grate
were defective. Dr. Arnott has recently improved
its construction with such success, as to claim for
it the merits of a new invention. He has also efl’ected
certain other improvements, which may be easily added
to the common grate. And, first, with respect to the
consumption of smoke. The ordinary bottom of the
grate being removed, the space is occupied by a coal-
box with a solid movable bottom or piston, supported
below by a vertical rack or ratchet-bar, held in posi-
tion by a click, and capable of being raised through
one or more notches by means of a lever or poker.
In lighting the fire, the coal-box is to be first filled
with bituminous coal. Upon this is placed paper and
wood, and then the coked coal of the previous day’s
consumption. When this coke is kindled it ignites
the top layer of coal in the coal—box. Fresh coal can
then be brought up into the grate by raising the pis-
ton of the coal~box through a tooth or two of the
rack. The smoke, ascending through the incande-
scent fuel, is of course consumed, and a large or a
small fire may be had at pleasure, by raising with a
poker the burning coal, so as to admit more air. An
important adjunct to this arrangement is a conical
hood placed over the fire, with a cylindrical pipe at
the top, which passes into the chimney. A curved
portion of the hood is cut away in front so as not to
conceal any portion of the top of the fire. The effect
of this hood is to contract the chimney to the dimen-
sions of the cylindrical pipe at the top, so that the
products of combustion only are discharged into the
chimney shaft, instead of (as in ordinary cases) that
large volume of air from the room which cools and
dilutes‘ the smoke, diminishes the draught, deprives
the room of the larger portion of the heat of the fire,
and leads to a wasteful expenditure of fuel. In cases
where the Arnott ventilating valve is inoperative from
this deficiency of draught, the simple addition of the
hood is an effectual remedy, for no sooner is the
hood adjusted to a badly drawing fire than the valve
flies open, and a powerful ventilating current passes
through it. The air required for the combustion of
the coal is supplied by a ventiduct opening not imme-
diately under the grate, as in the 'Polignae stove, but
under the fender. The perfect, but economical com-
bustion of the coal, in this arrangement, is shown by
the fact, that no soot is deposited in the chimney,
while the combustion is so slow that the fire will con-
tinue burning all night. In order to supply the coal-
box with fresh fuel, a flat metal plate ‘attached toa
handle is slid in over the piston and under the burn-

ing fuel: the piston is then lowered to the bottom,
the box filled with coals, and the plate withdrawn.
The cylindrical portion of the hood is furnished with
a throttle-valve, for regulating the draught at plea-
sure.1
WASH. See DISTILLATION.
WATCH. The going-part of clocks is sometimes
termed the ware/apart‘. Under the article HonoLoeY
we alluded briefly to what are called remorztoz're, or
gravity cscapememfs. At the time when that article
was written it could not be said that any of the nu—
merous inventions of that class had been successful,
although they have engaged the attention of the most
scientific clockmakers, both professional and amateur,
for nearly a century. It is important to observe the
distinction between imz'n-remom‘oz'res and r'emorzz‘oz're-
escapemerza‘s. ‘In the former, a ‘scapewheel of the or-
dinary kind, or of any kind, is driven either by a small
weight raised by the clock at intervals, of half a minute
generally, or by a spiral spring on the scapewheel
arbor, wound up a quarter or half a turn at those in—
tervals ; and at the same time the minute-hand moves
with a visible jump, so that the time can be taken
from it as exactly as from the seconds-hand of an
astronomical clock.
This was the construction of the large clock with
cast-iron wheels in the Great Exhibition, and now at
the terminal station of the Great Northern Railway
at King’s Cross, London, for which the council medal
was awarded to the late Mr. Dent; and its superiority
to the gravity train-remontoires, which had been pre—
viously used in the best French turret—clocks, was so
“evident, that the present Mr. Dent (of the Strand) has
introduced it, at his own expense, into the Royal
Exchange clock in the place of the gravity remontoire
with which that clock was originally made; and the fric-
tion is so much less, that only two-thirds of the former
going weight is now required. A full description of
it is given by Mr. Denison, who invented it, in his
Treatise on Clocks, (page 240,) published in Weale’s
Rudimentary Series. -
But although by means of a train-remontoire a
constant force on the scape—wheel may be obtained,
(for the variation of the force of the. spring from tem-
perature is far too small to affect a clock with a dead
escapement,) the pendulum still remains subject to
the variations of friction on the pallets; and, there-
fore, unless they are kept clean and well oiled, the
force of the escapement cannot be regarded as con-
stant; and the same necessity remains as before for
delicate construction and high finish of the escape-
ment itself. But in a paper in the Cambridge Philo—
sophical Transactions of 1853, and in the 60th num-
ber of the Journal of the Society of Arts,‘Mr. Denison
has described a new gravity-escapement invented by
him,_.with the practical details found to be the most
suitable for its construction after the experience of

(1) At the time when we are writing (March 1854), Dr. Arnott
is preparing a pamphlet descriptive of this stove and other im-
portant matters connected with the art of warming and ventila-
tion, which he has improved with so much scientific skill, inven—
tive power, and liberality. We take this opportunity of express-
ing our respect for his truly patriotic exertions.
WATCH.
939
several clocks of different sizes in which it has been
adopted, as he states, with complete success, and, with"
the approval of the Astronomer Royal, after severe
trial of one of these clocks at Greenwich. The fol—
lowing is the substance of his description.
Fig. 2291 is the back elevation of an astronomi-
cal clock. The three-legged scapewheel is set near
the bottom of the frame behind the back plate, with
its back pivot in a cock: it
has on its arbor a fly FF
like a common striking fly
between the plates, only
larger, and a pinion of 8
driven by a wheel of 80 on
the arbor which carries the
seconds-hand. The rest of
the train is the same as
usual, only inverted in po-
sition, and there is no
longer‘ any occasion for
the high-numbered pinions
generally used in astrono—
mical clocks, as the friction
of the train is entirely out
off from the pendulum.
A simple proof of this is,
that doubling the clock
weight produces no sensi-
ble effect 011 either the are
of the pendulum or the
time. A heavier weight
Imllll'llllllm
a if!
2
.vx':
g‘ if‘ ‘ \\
it
.€
All





p11



i , .i'i‘i' at
Y'\Hml'l ‘ than usual is. required,
a ' J? . .
, W p, ., how ever, on account of the -
// W '3 additional pinion and the
iii/i i, ‘_ fly. The pendulum is here
w j . represented as just leaving
‘ M » the right arm or pallet and
‘a taking up the other; and
k I as soon as the stop s is
\ 5"” W P drawn quite away from the
Fir- 2291- tooth now resting on it,
the scapewheel will turn, and raise the other pallet by
means of the pin rz, which is now uppermost, until the
tooth belonging to it is caught by the stop 8’ on that
arm. If the are at which the pendulum 1? leaves one
pallet and takes up the other is called a, and the ex-
treme are a, each pallet ascends with the pendulum I’
from c to a,.but descends with it not only to 0, but to
-——c on the other side of zero; and consequently the
pendulum. receives an impulse from the weight of each
arm alternately through the are 2 c. The seapewheel
evidently turns once round in 6 beats of the pendulum;
and that gives a large enough motion at each beat for
the fly to restrain its velocity, and thus prevent it
from moving so fast- as to jerk the pallet too far out,
in which case the tooth may not be caught by the
stop, and then the wheel runs on still faster, misses
several beats, and perhaps breaks a tooth when it is
caught by the stop descending again. This is called
tripping, and has been the principal mechanical diffi-
culty of gravity escapements. '
Even those escapements which have been tolerably

safe against actual tripping under any probable varia-
tion inxthe force of the clock train, have sometimes
been liable to another miscarriage quite sufiicient to
injure the character of gravity escapements generally.
Though the force of the scapewheel may not send
the pallet so far as to let the tooth slip past the stop,-
it may send it further than it ought to go and would
go if it were lifted more slowly, and then the pressure
of the tooth on the stop is generally suflicient to hold
it there; and the consequence is that the pendulum
does not begin raising as soon as it ought to do, viz.
at the are c before-mentioned; and as the pallet will
always descend with the pendulum to the same place,
the impulse is increased, and the rate of the clock
altered. In some of the gravity-escapement clocks in
the Great Exhibition, you could sensibly increase the
arc of the pendulum in a few minutes, by putting
some extra force on the clock train; which showed
that they failed in the very first essential of a gravity
escapement. Here this is prevented by two things;
first, by the fly, which moderates the velocity of the
scapewheel ; and, secondly, by the length of the
locking teeth, the points of which are five or six times
as far from the centre as the lifting pins, and there~'
fore the pressure on the stop is so much less than
where the lifting and the locking are both done by the
same teeth, and is so little, that if an arm is by acci-
dent raised too high it will not stay there, but falls
again, and the face of the pallet rests on the pin which
lifted it, until the pendulum arrives and carries it off.
The small amount of friction at unlocking also ren»
ders the pendulum indifferent to the absence or pré'~
sence of oil on the stops, and they require none, except
just enough to keep them from rusting. Everybody
who knows anything of clockwork will recognise this
as a point of primary importance in any improvement
in escapements.
All other gravity escapements involve at least as
much delicacy of construction as the finest dead es-
capement. This, on the contrary, requires solittle
that it is hardly possible for a workman intending to
follow the rules given for its construction,‘ to make it
so that it willnot act perfectly; and, consequently,
in turret-clocks, besides the advantage of being able to
use east-iron wheels in the going part as well as the
striking, there is no longer any occasion for long and
heavy pendulums.
The distance of the points of the scapewheel teeth
from the centre should not be much less than gth of
the length of the arms (down to the stops): and the
lifting pins should be glgthof that length from the
centre. The are, before called a, will then be about
45', or the pendulum will receive its impulse through
90'. The steps and the lifting faces of the pallets
may be so adjusted as to make the depth of locking
about Tfi-(is of the distance of the pins from the centre
of the scapewheel, or (in round numbers) 56th of
the length of the arms. The arms should be only
heavy enough to make the pendulum swing about 2°
from zero. In astronomical clocks the length of the
arms has generally been made 6 inches; in turret clocks,
9 ; but there is no particular virtue in these sizes.
940
WATOHI
The bend of the knee in the legs of the scapewheel is
determined by the rule, that the pins and the points
of the teeth alternately should lie on the radii of a
regular hexagon. The stop on the pallet, which is
struck upwards, must be set a little higher than the
scapewheel centre, so that a straight line from there
to the stop may form a right angle with the arm; for
if the stop is lower than this, the blow will not be
given in the direction of the arm, and will have a ten-
dency to throw it outwards, which may as well be
prevented, though it may not be enough to make the
escapement trip. The other stop, however, should
not be set so high as to form a right angle in the same
way, because it will make the beats disagreeably un-
equal, and there is no occasion for it, as the action of
the teeth on that stop, if set lower, is not to throw
the arm out, but rather the contrary. The size of the
fly in a regulator may be determined by trial. If you
want a loud beat, you must have as small a fly as ap-
pears to be safe against any risk of tripping. In turret-
clocks the fly should be not less than 5 inches long,
by an inch broad, in each vane.
The scapewheel is made of steel not more than 5th
inch thick in a turret clock, and of course thinner in a
regulator; the pins of brass wire, riveted in. The scape-
wheel of the great Westminster clock does not weigh
half an ounce, although the pendulum weighs 6 cwt.
The points of the teeth should be made tolerably hard,
but not quite sharp. The stops should be screwed on
soft, and adjusted to the proper depth of locking,
and then made quite hard and polished; and the
lifting faces‘ of the pallets the same. The pallets of
turret clocks may be of iron, only faced with steel:
in astronomical clocks they can hardly be made light
and stiff enough unless they are of steel, and not
above 113th of an inch thick. The lower ends are bent
backwards at a right angle, to embrace the beat—
screws in the pendulum, the action of which is obvious.
It is better not to put oil, as to the common fork, on
the points of contact, as there is no sensible friction,
and it may tend to stick the fork pins to the beat-
screws, and so resist the separation of the pendulum
from the pallets; but the heads of the screws should
be made of brass.
This escapement allows you always to set the clock
right within one beat of the pendulum without touch-
ing it, by merely lifting one of the pallets and letting
the scapewheel run forward, or turning it back, which
will alter the time by any even number of beats you
please: and the clock may be brought to exact time
without touching the pendulum, by the following
method :—
If the 10,000th part of the weight of a pendulum
is stuck on to- the rod half-way down its length, it
will make the clock gain a little more than a‘ second
a day: that being the place where any given weight‘
produces the maximum effect, and where any shifting
of that weight up or down produces the minimum
effect. Consequently, a sliding weight there is a bad
way of regulating a pendulum ; and on’the other hand,
if a collar is fixed there, and the pendulum so adjusted
that it goes nearly right with some small weight laid

on the collar, it can always have its rate altered by
any assignable quantity, by merely altering that
weight. The best way of making a series of weights
for the purpose is to try the effect of some weight
large enough to accelerate the clock a good many
seconds a day; then you will know what any aliquot
part of it will do; and from that knowledge make a
series of weights in geometrical progression, marked
%, s, l, 2 (these will be quite enough), according to
the number of seconds a day by which they will in-
crease'the rate when laid on the collar, and therefore
diminish it when taken off ; which can easily be done
without disturbing the pendulum. One ounce will do
a second a day in a pendulum of more than a quarter
of a ton, and 10. grains in the common mercurial
pendulum of an astronomical clock.
This escapement also, on account of its indepen-
dence of all variations in the force and friction of the
train, is well adapted for electrical clocks and dials;
meaning by the former, clocks which wind themselves
up by electricity, and by the latter, dials with the hands
driven by electrical connexion with some standard
clock at a distance, whether an electrical clock or not.
A clock of this kind is easily made, as follows :-—-
There is no great wheel or barrel; but on the centre
wheel arbor there is a common spring-going ratchet
(but with a weaker spring than usual) with 120 teeth.
A lever is placed opposite to it, with a gathering
click, so that when the lever is lifted by the tem-
porary magnet at every half minute, the click drives
or winds up the going ratchet the space of one tooth,
and so of course the clock is kept going. The‘ elec-
trical contact may be made at every half minute,
either as in Mr. Shepherd’s clocks, described in article
HOROLOGY, or perhaps better as follows: On the mi-
nute-wheel arbor put two half snails, so shaped and
adjusted that a light lever which they raise may just
drop on to the contact plate, connected with one of the
battery wires, and be lifted off again at the next beat
of the pendulum. By this means it is found that the
contact can be made with great certainty at every
30th second, and allowed to last no longer than one
second; and it is a contact without friction, which is
almost essential to prevent oxydation of one of the
points of contact, even if made of platinum, and it
also consumes less force of the clock than a pin press-
ing against a spring for a few seconds. If the going
ratchet is fixed to the arbor, the minute-hand will
move by half-minute jumps ; if the wheel is fixed, and
the ratchet loose, the hand will move slowly as usual.
Where the hands of an electrical dial are to be
driven by connexion with a standard clock, as they
usually are, at half minutes, or even at every second,
if they are large or exposed to the wind, it is found
that the method of driving by pallets cannot be relied
on; and a double ratchet-wheel with a gathering
click, and backward and forward clicks, has been
usually resorted to. But even this method cannot be
depended on with certainty against the action of
wind, which may either resist the motion of the hands
at the critical moment, or drive the. wheels on several
teeth instead of one; and the‘ adjustment of the two
WATER.
_941
ratchets is also a matter of some diificulty. Mr.
'Denison has therefore contrived a new arrangement of
electrical dial-work, which he says is found to be safe
against any pressure of the wheel, either backwards
or forwards, at the moment of either making or break-
ing the electrical contact. In Fig. 2292, n is the wheel
carrying the minute-hand, with 120 square teeth.
When the contact is made, the magnet M raises the
lever LEIB into the position here represented, and
with it the gathering or driving click A. The pin at
B at the same time lifts the forward click 13 D out of


Fig. 2292.
the teeth, and the spring behind it makes it trip on to
the top of a tooth, there being a little play left in the
pivot-hole n for that purpose. The top of the lever
is also made just to reach the tail of the backward
click 0 I‘, when it is raised; so that when things are
in this state it is evident that the wheel cannot be
driven forward without pulling the lever away from
the magnet, which no wind would be strong enough
to do while the electrical circuit is complete; and as
soon as it is broken, the lever ought to go, and will
go, with or without the assistance of the wind, being
pulled down by the weight w, till it rests on the
banking-pin below it; and in so doing, the click A
will drive the wheel one tooth, and the click :5 will
drop into the tooth next to it, and be pushed back
against its stop at n, and there stay till it is lifted
again by the lever. Another advantage of this plan
is, that the weight is always ready to pull away the
lever from the magnet as soon as the magnet ceases
to act, as it is certain to be enough to overcome the
residual magnetism which sometimes prevents the
lever from falling where the driving of the wheel is
done directly by the magnet. Moreover, the wind
cannot here prevent the lever from being lifted; if the
magnet can ever lift the weight it always can; and
even if the resistance of the wind should be too
great for the weight at the moment of breaking con-
tact, the weight is certain to have an opportunity of
beating the wind before the next half-minute, and so
a move can never be lost. It only remains to be
added, that none of these arrangements are patented.
WATER, in chemical language, is called the pro-
toxirle of hydrogen. Its symbol is HO, and its
equivalent number 'is 9. The relation which water
bears to hydrogen, and the mode in which this gas
may be obtained from it, are explained under HYDno-
GEN and OXYGEN.
Under the chemical properties of water may be in—
cluded many qualities and uses which are not strictly
chemical, but which are yet better noticed here than
among mechanical or physical properties.
In its ordinary state as a liquid—neither so cold as to

solidify, nor so heated as to vaporize—water is colour-
less, transparent, inodorous, and insipid. A cubic
inch, at a temperature of 62° F. and at a barometric
pressure of‘ 30 inches, weighs 252458 grains. As
water furnishes the unit of specific gravity for all solids
and liquids, and as atmospheric air furnishes the unit
in respect to air, gases and vapours, it may be con-
venient to bear in mind that a cubic inch of atmo—
spheric air, at the pressure and temperature above
named, weighs 9'31 grains ; and that therefore water
is, bulk for bulk, about 815 times as heavy as air.
Water is very slightly compressible, and is an imper-
fect conductor of heat and electricity. Water ex-
pands by heat and contracts by cold, like other sub-
stances; but it is subject to a singular exception in
this respect, that it expands instead of contracting in
descending from a temperature of about 40° F. to
that of the freezing point, 32° F. Were it not for this
property, ice would sink instead of floating in water,
and lakes and rivers, and probably whole seas would
become in winter masses of solid ice throughout.
The remarkable properties of water when raised to
so high a temperature as to vaporize, are explained
under STEAM; and the application of those properties,
under STEAM-ENGINE. Its properties under the solid
form are noticed under HEAT and Ion.
Water possesses different qualities, according to the
source whence it is obtained. Rain, dew, spring-water,
river-water, well-water, lake-water, marsh-water, sea-
water, mineral-Water, all are affected in quality by the
substances with which they have come in contact. The
colour, taste, odour, and medicinal qualities, are all
more or less likely to be influenced thereby. .Raz'rz-
water-is the purest of all except distilled water, although
it contains minute portions of many acids and other
substances which exist in the ‘atmosphere through
which it passes. It has high solvent powers, and is
hence very valuable in cookery, and in chemical
operations. [See RAIN-GAGE]. Ice-water is nearly
destitute of atmospheric air; it is :mawkish and in‘
sipid, and fishes cannot live in it. Snow-water is
nearly allied in quality to ice-water; some persons
think that it tends to produce the dreadful malady
called goz’z‘re. Dew differs principally from rain in
possessing a little more atmospheric air. Spring-
water derives its qualities from the strata through or
over which it flows: if it take up chloride of sodium
it becomes saline; if it take up salts of lime, it be:
comes what is called “hard ;” if it imbibe carbonic
acid, it becomes sparkling and pleasant to the taste;
but the most valuable spring-water is that which is
very nearly free from all these foreign substances.
River-wafer may, in some respects, be regarded as a
mixture of rain-water with spring-water; since it
comprises a portion which has only flowed over the
surface of the ground, and a portion which has per-
colated the strata beneath the surface. In most
rivers, however, the quality of the water is more in-
fluenced by mud and detritus in the bed through
which it flows than by any other circumstance; and
hence the necessity .of some mode of purification
whenever river-water is adopted for the supply of
“9&2
warnnwwarnn-conouns.
towns. [See FILTRATIONJ Well-water being gene»
rally obtained from a deeper source than spring-water,
is more likely to be affected by the mineral consti-
tuents of the soil. In the neighbourhood of London
well-water or pump- water is always hard, and is very
unfitted for washing, and culinary processes. It is a
curious circumstance, however, that Arlesz'rm well-wafer
is much softer, being brought up from a different kind
of strata. [See ARTESIAN-WELIr—BORINGJ Lake-wade?‘
partakes of characters intermediate between many of
those above noticed: if the lake have no outlet, such
as the Caspian and the Dead Sea, the water necessarily
assumes a peculiar character from this circumstance.
'Marslz-waler abounds in animal and vegetable matters,
and is for the most part both unpleasant and un—
Wholesome.
Sea-water contains many saline substances. The
analysis of the water of the English Channel was
given under SODIUM, Chloride cf. M. Laurens found
the ‘water of the Mediterranean to contain as

follows :—
Water 959'06
Chloride of Sodium . 27'22
Chloride of Magnesium 6'14
Sulphate of Magnesia 7'02
Sulphate of Lime . 0'15
Carbonate of Lime .. 0'09
Carbonate of Magnesia 0'11
Carbonic acid . 0'20
Potash 001
100000
Before such water can be fit for drinking, it is evi-
dent that the greater part of these saline ingredients
must be removed. It has long been a desideratum to
enable ships’ crews to use sea-water for many culinary
purposes, to obviate the necessity of taking out large
supplies of fresh water. Many contrivances for this
purpose have been invented; but the most effective
is Mr. Grant’s, by which the cooking of victuals and
the purifying of water are carried on at the same
time. The apparatus is called the “Dislz'llz'ny and
Coo/sing Galley.” The galley contains the fires and
vessels necessary for cooking. During the time when
the’ fires are lighted, a portion of the heat is applied
to ‘the exterior of vessels containing sea-water; the
water boils, and steam distils over, leaving the saline
substances in the still. The steam condenses into
nearly pure water, which is rather vapid through the
absence of air or oxygen; but a little agitation, and
access to open air, greatly lessens this defect. Most
of the government ships are now provided with
Grant’s apparatus. Where steam-power is used on
board, a ready means of distilling fresh water from
salt is furnished.
Mineral-water is noticed under a separate article.
See WATERS, MINERAL.
The various practical applications whereby the
physical properties of water are rendered useful in the
arts, are described under Aonnnuo'r ; Frnrna'rron ;
'Hrnnosra'rros AND Hrnnonrnamrcs; Pmirr; Warran-
ENGINE; WATER-WHEELS; "WATER-Wonxs. The
hydraulic action of the Archimedean Screw, and of
the Screwpropeller, is noticed under STEAM Navr—
carton.

WATER-COLOURS. The materials used for
water—colours do not differ much in respect to their
general character, from those intended for oil-painting,
except in comprising a larger number derived from
the animal and vegetable kingdoms. Many of the
salts produced by the combiuat ion of sulphuric, nitric,
carbonic, muriatic, acetic, prussic, and other acids,
with the oxides of iron, copper, tin, lead, zinc, mer-
cury, and other metals, are sufficiently beautiful in
colour to be employed as pigments; as are also some
of the oxides and chlorides of those metals. Accord-
ing as the pigment is to be mixed with water, with
size, with wax, or with oil, for different kinds of
painting, so are there variations introduced in the
mode of preparing them. Water-colours require
more delicate treatment than any of the, others in
grinding, levigation, evaporation, drying, &c., to adapt
them for the purposes of miniature painting. Liquid
colours, too, for the use of map-colourers and others,
require that the solid ingredients shall have dissolved
completely in the liquid, to avoid the formation of any
sediment.
The Council of the Society of Arts, willing to aid
the labours of students in art, by providing them with
good materials at a low price, recently offered a pre-
mium to any one who could manufacture a box of
paints, comprising a small number of cakes of mode-
rately good quality, which could be sold retail for
one shilling. This, of course, was not intended so
much to aid practised artists, as to afford cheap but
useful aid to young students about to commence
practice. A colour-maker in Bunhill Row suc-
ceeded in producing a shilling box of colours which
met the requirements of the committee; and this
neat little production is generally considered to be a
remarkably cheap specimen of what can be done in
this art.
There can be no doubt that improvements in chemis-
try ought to lead both to improvements in the quality
and diminution in the price of colours and pigments.
The artificial ultramarine is only one among many ex-
amples of really beautiful colours which are now pro-
duced as substitutes for others enormously expensive.
Many of the reds, scarlets, crimsons, and carmines,
are very expensive, in the particular tints which
artists occasionally require; and it is a legitimate ex-
ercise of chemical research to find lower priced but
equally useful ‘substitutes for these. At the present
time, an attempt is being made to apply electro-che-
mistry to colour making. It is known that when the
acids and metals in a galvanic battery have performed
their part, by assisting in the production of an elec-
tric current, the residue in the battery is generally
reckoned of no account, and is abandoned. But this
residue often consists of or comprises the very ele-
ments which constitute ordinary pigments. Hence,
Dr. Watson has taken out a patent for a mode of
making colours by electricity. He adopts a form of .
battery, and selects his materials, with a view to the
production rather (if a residue in the battery than of
a current in the wire; the former being the end in
view, and the latter a means to that end. The patent
WATER-EN GINE.
941.3
‘is being worked by the “ Electric Light, Colour and
Power Company,” who havewestablishedwworksvfor
the purpose at Wandsworth ; and also hope to be able
to apply the electric power generated in the wire to a
useful purpose, as well as the salts and other com-
pounds generated in the battery. The colours thus
produced are dry colours, in powder, or in lump-—
not ground in oil or in water like colours actually
prepared for the artist. I
Many kinds of water-colours are noticed under va-
rious headings, such as GARMINE~GOBALT-—GOCHI-
NEAL—ULTRAMARINE, &c.
WATER-ENGINE. This is an ingenious con—
trivance for obtaining motive power by the descent of
a column of water. A water-wheel depends for its
eficiency on a very slight descent of a large body of
water; but the water-engine is more suitable for cir—
cumstances in which a small column of water descends
from a considerable height. It is in mining opera-
tions that this machine appears most fitted to render
useful service. At the silver-lead mine of Huelgoat,
in Brittany, two water—engines of considerable size are
employed. They are worked by a column of water
descending from a height of 60 metres (about 200
feet). The power produced by this descent of water
is applied ,to the working of a pump-rod; and the
pump to which this rod belongs, brings up water from
the vast depth of 230 metres (750 feet). Thus is
afforded an instructive example of a mode in which
one portion of water descending 200 feet, may cause
another portion to ascend '7 50 feet. So well are the
water-engines at Huelgoat constructed, that they are
estimated to render available two-thirds of the power
produced by the descent of the upper column of
water.
In the “ single-action water-engine” there is a
piston which works up and down in a cylinder; the
upward movement is occasioned by the pressure of
water, and the downward movement by the weight of
the piston and its connected metal work; whereas,
in the “ double-action water-engine,” the piston is re-
ciprocally acted on by water above and below. The
water—engines set up by M.‘ Juncker at Huelgoat are
on the “single-action” principle. A piston moves
vertically in a cylinder, which is connected near the
bottom with a horizontal pipe bringing water from
the descending column, and also with another pipe
intended to carry away the water when it has exerted
its action on the piston. When the admission-pipe
allows the water to act on the lower surface of the
piston in the cylinder, the piston becomes driven up
to the top of the cylinder, and‘ the piston-rod draws
upward a pump~rod or any other mechanism with
which it may be connected. As the cylinder is open
at the top, the piston, pressed upon by the weight of
the atmosphere, would have a tendency to descend;
but this it cannot do until the water below it has been
removed from the cylinder. This removal is effected
by an ingenious subsidiary apparatus. Projecting from
the top of the piston, and near one side of the cy-
linder, is a vertical rod with 2 cleats or studs; these
studs catch against 2 cams outside the top of the

cylinder—one stud lifting one cam during the ascent
of the piston; eandetheother' stud drawing down the
other cam during the descent of the piston. These
cams are at the two ends of a circular are, connected
by intervening leverage with a small vertical piston-
rod; and the whole arrangement is such that, when
the large piston rises, the small piston-rod rises also.
This small red has 2 pistons which work in a small
vertical tube, and alternately open and shut the
mouths of 2 horizontal tubes. These horizontal tubes
are connected, the one with the admission-pipe and the
other with the discharge-pipe. The end and object of
these subsidiary arrangements are, that when the
piston has been driven up to the top of the large
cylinder, the connexion with the supply-pipe becomes
closed, the connexion with the discharge-pipe becomes
opened, the water flows out of the cylinder, and the
piston descends. A reversal of all these conditions
causes a re-ascent of the cylinder; and thus a reci~
procal action is kept up, well fitted for working a
pump-rod. -
The mechanism of this single-action engine is in-
tricate. Those who wish to study it in detail will
find it well described, and well illustrated by en-
gravings, by M. Delaunay.1 We will proceed to de-
scribe the “double-action water-engine,” which is
more easily illustrated and comprehended.
The double-action engine differs from the single-
action chiefly in these two particulars—that the
cylinder is closed at the top as well as at the bottom,
and that there are two supply-pipes, at the top and
bottom of the cylinder respectively. The piston P,

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Fig. 2293. DOUBLE-ACTION WATER-ENGINE.
Fig. 2293, moves vertically in the cylinder 0. The
water descends by the supply-pipe s, and passes along
two horizontal pipes H, H’ ; and thence through the

(1) Come Elémentaire de Méchanique Théorétique et Appli-
quée. Paris, 1851. '
9424:
WATER-EN GINE—WATER-WHEELS.
two openings 0, 0', into the cylinder. Two pistons p, _p' ,
fixed on the same rod, move vertically in a small cy-
linder placed by the side of a larger cylinder. In the
actual position represented in the engraving, the
water can pass through the lower horizontal pipe H’,
and through the lower opening 0', into the space he-
neath the piston in the large cylinder ; it hence exerts
an upward force, suificient to drive the piston to the
top of the cylinder. But there is water resting‘ on the
piston also, and it ‘is necessary that this water should
be removed in order that the piston may ascend.
This water, it will be seen, has a free communication
by the upper opening 0 with the discharge-pipe 1).
The piston, being pressed forcibly from beneath, rises,
and drives out the water from above it into the waste
tank T. If, at the moment when the piston attains
its greatest height in the cylinder, the two small pis-
tons 19,12’ were lowered so as to come respectively
beneath the openings 0, o’, it is evident that the upper
opening 0 would communicate with the upper supply-
pipe s; while the lower opening 0’ would communi-
cate with the discharge-pipe D. The pressure would
then cause the piston to descend, and the water he-
neath the piston would flow out of the cylinder
through 0' and D. Now, to bring about this action
of the two small pistons 12,10’, the mechanism at the
top of the engine has been contrived. The up and
down movement of the rod to which these two pistons
are attached is produced by means of another piston
)2” adapted to the upper end of the rod; it moves in
a cylinder of its own. A four-way cock, r, opens a
double communication between this small upper cy—
linder and the upper supply-pipe on the one hand, and
with the discharge-pipe on the other. In the position
indicated in the engraving, the supply-water passes
from s through the bent pipe B into the small cylin-
der, and forces up the small piston 19” : while the
water which is above this little piston finds an outlet
by the smaller discharge-pipe (Z. If the four-way cock
be turned one quarter round, the water obtains access
to the upper surface of the small piston, pressing it
downward, while the water beneath the piston finds
its way to the small discharge-pipe. Whenever the
small upper piston _72" descends, it causes the descent
of the other two small pistons, 22, £0’ ; and these regu—
late the admission of water into, and the discharge of
water from, the larger cylinder. The movements of
the four-way cock are governed by the lever L, which
is itself governed by the ascending and descending
movements of the piston-rod in the large cylinder.
The whole machine thereby becomes self-regulating.
The water-engine is most likely to be valued in
countries where steam-power. through the high cost
of. coal, is not much adopted.
WATER-WHEELS. Among the modes in which
a stream of flowing water is made available as a source
of mechanical power, the water-wheel is one of the
most familiar. .In all forms of the machine, the water
is in considerable volume, with only a small descent;
the axis of the wheel is generally horizontal, but in
some varieties'it is vertical. The chief kinds ofwater-
wheel are antlers/wt wheels, oversfiot- wheels, dream.‘

wheels, and horizontal wheels, varying chiefly in the
point at which the water impinges upon the periphery
of the wheel.
An undersizot wheel (Fig. 2294) has a number of
float—boards F f f or plane-surfaces ranged round its cir-


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Fig. 2294. UNDERSHOT WHEEL.
cumference, so shaped and placed that the water may
fall upon them, and may by its pressure cause the
wheel to rotate on its axis W. The water is brought
by an inclined canal or channel o to the lower part of
the wheel. The wheel is here represented with 24:
float-boards; but it may have any greater or lesser
number. It is evident, from the direction in which
the water approaches the float-board F, that a force
will be produced tending to rotate the wheel; and
as each float-board comes in succession into that
position, the force is virtually continuous. ~
In the overs/20¢ wheel, Fig. 2295, the construction
and action are somewhat more complex, and afford
more scope for the exercise of the engineer’s judg—

OVERSHOT WHEE L,
Fig. 2295.
ment. The wheel L R has a number of buckets
1366' instead of float-boards, ranged round its cir-.
cumference. When the water flows along the chan-
nel c to the bucket 6, it tends to put the wheel in
motion; if this bucket were exactly over the axis W,
the wheel would neither tend in one direction nor the
other; but the bucket being on one side of a vertical
line passing through the axis, a leverage is obtained
*represented by the'distance 6w, being the horizontal
WATER-WHEELS——WATEIt-WOBKS.
94-5.;
distance ‘from the- axis to a vertical line B b passing
through the centre of the'bu'cketi *Wh'enr the bucket,
by the .motion of the wheel, comes into the position
b’ b’, the‘ leverage is increased from b w to 11' W, and
the mechanical eflect is increased. This increase con-
times until the bucket arrives at the extreme right n
of the vibes], after which it decreases.“ There is a
further decrease also, due to the flowing of the water
out of the ‘ bucket. It is plain that much of the
elficacy of ithe machine depends upon the power of
the bucket .to retain the water until it reaches near
the bottom of the wheel; the form shown in the en-
graving (to illustrate the principle) is very defective;
the water ‘begins to flow out at n, whereas, with a
better 'fOI‘IIlt of bucket, a greater power of retention
might be rensured. The water ought not to begin to"
flow out-"until the bucket has passed the point of
greatestl leverage'at It; and it ought not to have com—
pletely flowed out until the bucket has arrived nearly
at the bottom.‘ The variations adopted by engineers
in overshot water-wheels are numerous, on account of
the influence exerted by the number, shape, and ar—
rangement of ‘the buckets.
A breasif wheel, Fig. 2296, presents its axis almost
on a level width the surface of the water. The wheel,
inn, has I'floatlboards instead of buckets. The water
approaches by the channel 0, and falls upon or against
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Fig. 2296. nnr-zAs'r WHEEL.
the float-board 6 ; engineers differ in plan, some
placing this point of contact a little above, and others
alittle below the level of the axis A. The mill course it
is a channel accurately fitted to the curve formed by
the ends ‘of _all the float-boards; so that the space
between any two boards forms a kind of box, which
,' retains the water until the board has arrived near the
.lowest point.
There is a sluice or shuttle s, moved
by a pinion 1?, to regulate the quantity of water
admitted to. act upon thev wheel.
The bore-‘zontal wheel, Fig. 2297, is occasionally
employed .where a vertical axis of motion is required,
as a means .of producing it without much loss of
power. ‘A .m'ill-stone is frequently moved in this
manner- The horizontal wheel difi’ers little from the
undershot wheel except in the direction of the axis;
< {the mill-course and the float-boards are nearly alike in
- voL. II.

both. The water-course, first oblique, is made nearly
horizontal, by the time the water impinges upon the
float-board. In some forms of construction the floats
are in radial lines from the axis A, while in others



Fig. 2297.
HORIZONTAL WHEEL.
they are oblique to the radii: where this obliquity is
very considerable, the water is not turned into a
horizontal course, but descends from c to the float-
board F, and thus causes the wheel to rotate.
It is demonstrable, by the theory of hydrodynamics,
that if the velocity of the steam be given, the effect
on any of the wheels will be as the water expended;
that if the expenditure of water be given, the effect
will be as the square of the velocity; and that the
efficacy of an overshot wheel is to that of an under-
shot wheel—the weight of water, the aperture, and
the diameter being given—as 18 to 5 nearly.
WATER-WORKS. In the articles Aounnuor
and FILTRATION many details will be found relating
to the supply of water to large towns. In the pre-
sent article a few additional matters will be treated,
relating to the metropolitan supply. .
Before the time of Sir Hugh Myddleton, London
was partly supplied with water by springs. There
were public reservoirs in the city; and to these reser- '
voirs conduits or pipes were brought from Tyburn in
1236, from Highbury in 14:38, from Hackney in 1535,
from Hampstead in 1M3, and from Hoxton in 1546.
Water-works were formed at London Bridge in 1582,
with water-wheels turned by the ebb and flow of the
river. Until these works were constructed, no houses
were supplied direct by pipes; for the inhabitants
were dependent on water-carriers, who brought the
water in carts from the conduits and reservoirs. In
1618 Sir Hugh Myddleton brought to a- completion
his great undertaking of conducting the water of the
New River to London, and conducting branch-pipes
from the New River Head or Reservoir to the houses
of the consumers. It is too late now to inquire
whether such a large undertaking as supplying a city
with water should be managed by joint-stock compa-
nies or by the government; the example set by
Myddleton’s Company has been followed; other com-
panies have been formed from time to time; and
London has ever since been supplied with water by
companies only.
During the inquiries made by the Board of Health
relating to the London Water-supply, in 1850 and
1851, the respective companies were required to
make a return of the expenses which they incurred
for every million gallons of water supplied. ‘Their
returns were as follow :—
3 2
916‘
WATER-WORKS.

£ .9. d.
New River............ 9 17 4
EastLondon 6 7 731,}
Southwark.............................. 5 9 4
West Middlesex.... 16 9 7
Lambeth................................. 15 0 6%
Chelsea..................... . 19 10 4,1;
Grand Junction 9 14 6%
'17- 210;
Hamplstead.....,:..—...',._,_.. 22 ‘5 7%‘ .
;irverage, (about £101 10. _ 10
The armies-e,terwetriihenafepstaa and, as S'outh-,_
wark Companiesifilsf has;remananye'grea. ' Itfwias
at the same timerestim‘ated. that average charge -
to the public was about 7'2'5'lj per, million gallons,
leaving about gths of the gross receipts to pay interest -
on the capital expended.‘ " v
The sources whence- th'ese comj'ianies-obtain their
supply ‘are as follow :.——.Tl,1e'Nozo_ liz'ner Company, from
the Lea River and "adjacent-springs, and from four
deep wells sunk into' the :chalk. The East London
Company, from the Leaf near Old Ford. The [ram
Company, from the Itavensbourne: below Lewisham. The
Hampsz‘oad Company, from springs near Hampstead,
and from two Artesian wells. The ,Lamlezfn Company,
from the Thames at Thames‘ Ditton. The Chelsea
Company, from the Thames near Chelsea. The Soul/z-
won'lr anal Venn/loll Company, from the Thames near
Battersea; the West" Middlesex Company, from the
Thames nearlBarnes; and the Gmnzl Junction Company,
from the Thames near Kew, Bridge.
In 1850 the various companies supplied the follow-
ing quantities sea-"The. Newltiver' Company supplied
83,206 tenements .with 5,278 million gallons,- or 174:
gallons per house :Iper day; The East London Com-
pany supplied 56,679'tenements with 2,956 million
gallons, or \lll8i'gallons . per house per day. The
Southwark-Company. supplied 84,8641 tenements with
1,820 million gallons, or 1&3 gallons per house per
day. The West Middlesex Company supplied 24A80
tenements with 1,109 million gallons, or 124a gallons
per house per day. The Lambeth Company supplied
23,396 tenements with 913 'million gallons, or 107
gallons per house perday. The Chelsea Company
supplied 20,996‘ tenements with 1,804 million gallons,
or 170 gallons per house per day: The Grand Junc-
tion Company supplied 141,058 tenements with 1,127
million gallons, or 220 gallons per house per day.
The Kent Company supplied 9,632 tenements with
328 million gallons, or. 98' gallons per house per day.
The Hampstead Company supplied 41,4190 tenements
with 1116 million. gallons, or 89 gallons per house per day.
It may be assumed that, where the supply- per house
is small, the houses in that district are generally of a
humble character. In the aggregate, 271,794 tene-
ments were ‘supplied with 1&0 gallons each per day
on an average? The total supply furnished by all the
nine compani_es,-including tenements, large establish—
ments,- streetii watering, flushing-sewers, and fires,
amounted to 16,7 418 million gallons in the year.
During the last thirty years'discussions have been
carried on concerning the necessity of obtaining a
better quality and a larger quantity of water for
London, and concerning the source whence it can be
obtained. Some engineers and medical inquirers
have advocated a supply from the Thames, high up in
its course; some have advocated the Colne and other
rivers, which flow into the Thames from Hertford—
shire; some have proposed to use the catch-water
from a large barren district near Bagshot ; while
otherslhave advocated the boring of artesian wells.
-,The ‘opinions on ;alllthese points .are very conflicting;
and. the want-'of unanimity‘zon" the part of engineers
and medical"inentseemsito have' brought the whole
afiiair'to a~"'stan’dls_till,-isog~i'ari as new projects are con-
cerned; (The existing water-companies, alarmed at
the many new schemes which threatened them, offered
to make great improvements; most of them obtained
special- Acts of' Parliament ‘in 1852, for establishing
new sources of supply, (either in the Thames or the
Lea,) for filtering the water, and for reducing the
charge made to the public. These improvements are
now being carried out. The projectors of a new
Water-Company sought, in 1852 and in 1853, to ob-
tain an Act of Parliament; but the legislature has
deemed it right to give the old companies an oppor-
tunity of making their proposed reforms, before offer-
ing encouragement to a rival. The metropolis re-
mains in 1854!, therefore, dependent for water-supply
on the same nine companies which commanded the
supply ten or fifteen years ago.
The hydrodynamic principles on which modern
water-works are conducted are easy of description.
The ancients did not adopt the principle of pressure
whereby water will find the same level at the two ends
of a continuous pipe, however much the pipe may
dip at the centre; they were acquainted with the
principle, but they were deficient in the means of
providing large pipes of sufiicient strength ; and they
adopted the nynerlnol principle instead. In modern
water-works, when the source of supply is situated at
a higher point than any of the buildings to be sup-
plied, reservoirs are formed to retain a body of water
always in readiness; main-pipes descend thence to
the streets, service-pipes extend to the houses, and
cisterns and ball-cocks regulate the supply of water,
and prevent waste. Where the source of supply is
lower than the level of the streets and houses, as
where the water is obtained from a river, a different
plan must be acted on. The most usual course, in
- such case, is to construct one or more reservoirs at a
suitable elevation, and to supply them with water
through ascending pipes or mains by means of force—
pumps, worked by steam—power or water-power.
Provided the reservoirs so formed are sufficiently
elevated,‘the water may be made to flow from them
to the houses just as if the actual source of supply
were'at that elevation. Sometimes it is necessary to
supply houses at a greater elevation than the highest
reservoir; this object is usually eifected by employing
a pumping-engine to propel the water from the reser-
voir along the pipes which lie too high to be filled in
the ordinary way. To prevent the danger wh-ichxmight
arise from the application of too great a pressure by
the pumping-engine, a vertical‘ pipe is usually con-

nected with the pipes for the high delivery, and
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WATER-WORKS--WATERPROOFING.
947
carried up to an elevation equal to that of the highest
point to be supplied; such a pipe, which may be
erected in the reservoir, and left open at the top, or
turned downwards again in the form of a syphon, acts
as a sort of safety-valve. In some cases, as at the
Hyde Park Reservoir, the lofty pipes or syphons are
superseded by safety-valves loaded to a degree equal
to the pressure of the required column of water.
The old water-‘pipes of London were principally of
wood, formed of whole trunks of trees bored by ma-
chinery. Stone-ware pipes and coarse glass pipes
have been proposed as substitutes for the old wooden
pipes; but the only effective improvement has been
in the use of cast-iron. All the London water-com—
panies now use cast-iron mains to convey the water
beneath the streets, leaving the builders to employ
small lead-pipes to convey the water to the houses.
In the reservoirs of the several companies much
careful engineering is required. The sluices, valves,
and various outlets, often call for much carefulness of
treatment. The East London Water-works are pro-
vided with balance-gates of remarkable character. In
1833 the company made considerable alterations and
additions to their works. They cut a canal for the
purpose of bringing the water from a higher part of
the river Lea, near the Lea Bridge Mills, to their
works at Old Ford. To guard against any deficiency
of water for working the various mills on the Lea,
the company formed a large compensating reservoir,
covering 141 or 15 acres of land. This reservoir has
two entrances, one near Old Ford Lock, and another
above City Mill Point. At the former of these en-
trances is constructed a pair of tide or flood-gates,
for the admission of water only as the tide rises;
while at the latter there are three openings with six
balance—gates, for the admission of water from the
river Lea, and for discharging the water out of the
reservoir into the river for the use of the millers. As
the tide flows up the river it fills the reservoirs; and
when the tide ebbs, if required by the millers, the
water is allowed to run out into the river. MnWick'
steed devised a new kind of balance-gate for this
second opening. As the neap-tides at the point of
delivery rise, on some occasions, only a few inches,
and as consequently a very large body of water might
have to be delivered within a short space of time, with
so low a head or pressure, a great width of outlet be-
came necessary; if the ordinary sluice-gates had been
erected, the time required to open them would have
been above an hour and a half, and consequently the
whole of the water might not have been returned into
the river before the preceding low-water. Mr. Wick-
steed has so contrived his balance-gates that they can
be opened or closed in ten minutes, against a pressure
of water. There are six balance-gates inthree open-
ings; but a description of one gate will suffice for all.
The gate is made to work upon a vertical shaft as a
centre. One gate, when closed, works against another
gate on one side, while the opposite sides close against
a recess in the piers or side-walls. Whatever pres-
sure of water may be against the gates, there is as
great a tendency to keep the gate closed as to open it,

on account of the two halves moving in opposite direc-
tions round a centre; avery slight exertion of power,
therefore, will either open or close them. When the
gates are closed, and the water is to be retained in
the reservoirs, these eccentrics, working upon a shaft,
pinch the gates against their abutments, and thus
prevent any leakage; but when the gates are to be
opened, and the water discharged, the eccentrics are
loosened from their hold, and a small exertion of ma-
nual force, by means of a pinion and toothed quadrant,
suifices to open the gates.
WATERING OF STUFFS. See OALnNnnnINe.
WATERPROOFING is the art of making cloth
and textile fabrics in general impervious to moisture.
The purposes are very numerous, in the arts, to which
waterproof cloth is now applied. There ought, in
strictness, to be some other term employed, for most
of the varieties are airproof as well as waterproof;
the ordinary expression, however, is sufficiently well
understood. _
The cloth, whether of silk, cotton, flax, or wool, is
usually rendered waterproof by the application of
some solution to one or both surfaces. Leather occa—
sionally undergoes an analogous process of treatment,
but not so frequently as cloth. In many of the
earlier modes of procedure, the cloth was immersed
in a liquid, so as to become saturated with the water-
proofing agent. Mr. Hellewell’s patent, in 1835, was
of this kind; it bore relation to a composition of rock-
alum and whiting in water, in which the cloth was
dipped, and to a subsequent application of soap and
water. A patent by Mr. Hall, of Doncaster, in 1839,
specified two solutions; one consisting of alum, white-
lead, and water; and the other of alum, whitelead,
acetic acid, and water; the cloth, after being steeped
in one or other of these solutions, is passed through a
solution of quicklime, and then through a solution of
boiled moss. These are only two among many pa-
tented methods which, whether efi’ective or not, have
been superseded by better plans.
By far the greater number of methods relate to a
surface-application of some composition which is
generally somewhat thicker than a mere liquid solu-
tion. The use of tar for tarpaulins, and of oil for
oilskin, are familiar examples. One of many kinds
of varnish employed for this purpose consists of lin-
seed-oil, pipeclay, burnt umber, whitelead, and pounded
pumice-stone ; it is applied as a protective to tarpau-
lins, awnings, coach-covers,boat-cloaks, &c. _In 1840,
a patent was obtained by Mr. Newberg, for a mode
of rendering cloth waterproof without concealing its
textile surface :-—-the cloth is in the first place satu-
rated with a waterproof composition; it is then
dried on one side to form a hard film; while the other
side is kept moist, and is afterwards deprived of its
composition by means of spirits of turpentine.
But the modes of applying caoutchouc or india-
rubber for this purpose have given greatly increased
importance to waterproof fabrics. The process of
manufacturing mackintosh cloth, already described
under GAou'rci-Iouc, will serve to convey a general
idea of waterproofing as effected through the agency
3 P 2
9i8 WATERS,
MINERAL.
of this remarkable gum. It will suffice, therefore,
simply to enumerate the variety of articles now made
of waterproof cloth. The life-garments, life~belts,
life-buoys, and life—boats, made or covered with india—
rubber cloth, are numerous and ingenious. A safety-
boat has been invented, formed of a sort of canvas
bag impregnated with liquid india-rubber. Another
safety-boat has a framework of cork, and a covering
of india-rubber canvas. A third kind, tried some
years ago in France, consists of a skeleton framework,
each part of which is covered with india-rubber cloth,
and is provided with hinges. A boat about a hundred
feet long, loaded with nearly a hundred tons of wine
and wood, was safely navigated from Auxerre to Paris ;
it was then taken to pieces in a few minutes, and was
conveyed back to Auxerre in two carts—a remarkable
proof of lightness of construction. Macintosh’s
“life-cape” is made of a double thickness of india—
rubber cloth, with: apparatus for forcing air into
the interstice between the two layers. “ Yachting-
jackets” are made in a similar way. Beds, ham-
mocks, mattresses, cushions, and pillows, are made in
great variety, by different modes of applying the
indie-rubber cloth. Dr. Arnott’s “water—bed,” or “ hy-
drostatic-bed,” is a happy application of waterproof
cloth, as an envelope or covering for a space intended
to contain water. At the Great Exhibition, the uses
of waterproof cloth were fully and curiously illus-
trated. There were umbrella-tents, portable boats
for lake fishing and: duck shooting, portable baths,
boat-cloaks which were susceptible of conversion into
cloak-boats, boots and shoes, surgical and chemical
apparatus.
Many compositions have been proposed, and some
of them patented; for rendering leather waterproof,
by filling up the minute pores. Four or five may be
briefly described, as examples of the whole. Boiled
linseed-oil, mutton-suet, yellow bees-wax, and common
resin, are melted over a slow fire, and applied while
hot to the leather, which is itself to be made slightly
warm. Linseed-oil, resin, white vitriol, spirit of tur-
pentine, and white oak sawdust, are the materials of
another composition. Yellow bees-wax, Burgundy
pitch, turpentine, and linseed-oil, constitute a third.
A fourth plan consists in applying to the leather a
hot mixture of two parts tallow with one part resin.
Another proposal is to apply a coating of tallow to the
leather, and a second coating of one part copaiba
balsam with two of naphtha. The last composition
which we shall mention consists of caoutchouc, boiled
for two hours in linseed or neat’s-foot oil.
WATERS, MINERAL. Mineral waters derive
their distinctive characters from the formations or
strata through which they flow. Those of the primi-
tive formations are almost all thermal, and generally
possess a high temperature. Those of the older se—
condary formations are generally of a lower tempera-
ture. The newer, secondary, and the tertiary strata,
give forth cool mineral waters. The chemical contents
'——sulphuretted hydrogen, free carbonic acid, carbonate
of soda, other salts of soda and of lime, silica, sulphate
of magnesia, oxide of iron, free sulphuric and muriatic

acids—vary in almost every individual case ; but there
is a general tendency in mineral waters from the pri-
mary formations to a sort of similarity of chemical
contents, and so likewise in respect to the secondary
and tertiary formations.
Leaving out l/zermal waters, which are not desig-
nated mineral waters unless for some additional qua—
lity besides their high temperature, mineral waters
are often classed into saline, al/rnlz'ne, o/ialyleale, and
824129/5247‘60268. Most of the celebrated Spas belong to
one or other of these four classes,—the Cheltenham,
Leamington, Harrogate, Carlsbad, Marienbad, Kis-
singen, Wiesbaden, Seidlitz, and Baden. Baden
waters are saline-aperient, some hot and some cold;
or, rather, it should be said that some of the springs
at these places are saline—aperient ; for there are other
springs at the same towns possessing very different
qualities. Alkaline waters are met with at Bath,
Cheltenham, Leamington, Harrogate, Scarborough,
Carlsbad, Marienbad, Kissingen, Tiiplitz, Wiesba-
den, Vichy, and many other places. Among the
places at which chalybeate waters, or water in which
the iron is associated with much free carbonic-acid
gas, are met with, are Tonbridge, Harrogate, Brigh-
ton, Peterhead, Aix-la-Chapelle, Spa, Pyrmont,
Schwalbach, Marienbad, and Seltzer. Sulphureous
waters are found at Moffat, Askern, Harrogate, Aix~
la-Chapelle, and other places. It will be seen that
Harrogate possesses a large variety of these mine-
ralized waters. A small number of springs contain
iodine, and are on that account useful in certain
maladies. There are springs of this kind at Tewkes-
bury, Cheltenham, Gloucester, Leamington, Builth,
Llandrindod, and Kreuznach. Some others contain a
little bromine, and a few contain both iodine and
bromine.
Soda—water belongs to a large class of aerated
waters, comprising beverages artificially produced,
and having for the most part an effervescing quality.
Soda-water is, indeed, the principal of these; but
there are many different kinds, some intended to imi-
tate mineral waters, such as Seltzer-water, Pyrmont-
water, &c. In all such manufactured drinks, certain
powders are placed in a vessel, where they are acted
upon by water ; a chemical action ensues, which pro-
duces a beverage depending on the nature of the
powders. The materials for soda-water are carbonate
of soda and tartaric-acid; but other salts and acids
are employed in other instances, varying according to
the kind of beverage required.
An elegant little apparatus, Fig. 2298, has been
brought into use within the last few years, patented by
M. Mathieu as an improvement upon an earlier inven-
tion. It is calculated for the preparation of aerated
beverages in private houses rather than for sale, since
it can yield but a small quantity at a time. There are
two oval glass vessels, the larger one placed vertically
over the smaller. There is a passage of communication
from the one to the other, and in this passage is a cock
for drawing off the aerated liquid. The upper or larger
glass is filled with water, by removing the cover; and
the lower or smaller glass is supplied with the pow-
WATERS,
9&9
MINERAL.
ders. These powders are, as in other cases, of clif-
ferent kinds, according to the sort of beverage to be
produced. A small pipe descends from nearly the top
of the upper vessel to nearly the bottom of the lower,


‘732$,
‘4.; 4'? "t


Fig. 2299.
a little water descends through this pipe, mixes with
the powder, and produces gases; and these gases
ascend to the water in the upper vessel. Of course,
such gases only as are soluble in water are generated.
The gas chiefly used is carbonic acid, of which water
will absorb its own bulk, and by pressure can be made
to take up another volume. [See OAnBonIe Acrn]
As the gas accumulates in the upper vessel, the pres-
sure increases, and the water is thus enabled to take
up its additional supply. The two vessels are gene~
rally surrounded with a netting of wire or cane, for
security. In the simpler forms of the apparatus,
nothing further presents itself; but in M. Mathieu’s
improvement, there is a refrigerating contrivance.
In Fig. 2299, a view of this improved form is given.
The upper vessel is surrounded by an external shell
and sheath, so as to leave an intervening space; and
into this space may be introduced either ice or cold
water, or freezing mixture.
MM. Gaillard and Dubois’ Gazogevzc, or aerated
water apparatus, is a much more complicated contri-
vance. It contains three distinct chambers or vessels,
one for the water to be aerated, one for the effer-
vescing powders, and one to contain a small quan-
tity of water which is to act upon the powders. It
is necessary to separate all three vessels, when the
apparatus is to be prepared for use; and this is one
cause of its complexity. When all three have been
properly supplied, the finger is pressed upon a stud
or button at the top of the apparatus. This pressure
opens a valve which allows the water in the small
upper vessel to descend into the vessel containing the
powders. The gas, thus generated, can only escape
from the powder-vessel by descending a small tube
which dips into the larger vessel; and the water with
which this larger vessel is nearly filled becomes im-
pregnated with the gas. A second finger-stud governs
the valve of a small pipe which enables the aerated
water to flow from the ap- ray
paratus. The apparatus is
elegant in construction,
but it has not the elegance
of simplicity.
Mr. Masters’s aerating
machine is similar in prin-
ciple to Mathieu’s, though
differing in details. The
powders are placed in the
lower part of the apparatus,
and the water in the upper;
a little water descends to
the powders, and the gene-
rating gas rises. A stud,
acted upon by the thumb,
draws off the beverage when wanted.

Fig. 2300.
Fig. 2300
represents one among many forms of this pretty
apparatus.
Fig. 2301 represents Messrs. Tyler, Hayward and
Co.’s patent double soda—water machine; it is adapted
for bottles, and can make 300 dozen per day. There




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SODA-‘WATER ENGINE.
Fig. 230].
are two distinct machines in one frame, which can be
worked together or separate. The generator and gas-
holder are not represented in the out. o is a con-
denser, divided into two by a partition inside. Each
half has an agitator, worked by the wheel w. r P are
two condensing pumps, with regulating cocks for
admitting aerated water. 13 B are bottling cocks.
The pumps are worked by a beam 6. The beam, by
its reciprocating motion, causes the plungers pp’
beneath the pumps to ascend and descend in the bar-
rels of the pumps, forcing at each successive stroke
the gas and water together into the condenser. About
ten minutes are required to get the charge up, and
the bottling then goes on uninterruptedly.
Messrs. Tyler 86 Son have invented single and
950
WAX.
double soda-water machines of ingenious construc-
tion. Mr. W. Oox, of Manchester, has patented an
apparatus in which the impregnating gas may be sus-
tained at a pressure sufficient to cause its absorption
by the water without the aid of force-pumps. Bake-
well’s apparatus is another contrivanee, applicable to
the preparatlon not only of cooling drinks, but of
efl’erveseing drinks also, whether tonic, aperient,
diuretic, antacid, or pectic. In short, every aerating
apparatus may be said to comprise these two parts——
one to produce a gas, and one to mix the gas with
water.
WAX, an organic product of considerable impor-
tance, obtained from different sources, the chief of
which is the beehive, where it is used by the bees in
the formation of their cells. It has long been a
matter of dispute among naturalists, whether the bee
collects wax already formed in plants, or secretes it
from sugar in the mechanism of its body. The latter
view of the case, in accordance with the original
observations of Huber, is that which is now generally
adopted. It appears that those working bees, to
which the manufacture of wax is assigned, take a
quantity of honey or sugar into their stomachs, sus-
pend themselves in a festoon, by each insect attaching
the claws of its fore-legs to those of the hind pair of
the insect above it, and in this way, forming a number
of festoons crossing one another in all directions, they
appear like a dense curtain. They remain in this posi-
tion for 2d hours, during which the secretion of wax
takes place. The secretion is formed in certain mem-
branous bags in the body of the bee; and, as the
secretion goes on, the wax oozes through the mem-
brane, and forms in thin plates on the outside. The
process being complete, one of the insects detaches
itself from the rest, proceeds to the top of the hive,
and begins to build. It grasps one of the plates of
wax by means of a pincer, formed at one of the joints
of the leg, and draws it forward, when it is conveyed
by one of the fore-claws to the mouth. The insect,
with its mandibles and proboscis, reduces the plate to
a riband of wax, softening it with a frothy kind of
liquor, which makes it white and ductile. The other
insects proceed in a similar manner, and with such
celerity, that in a new hive, a comb 20 inches long
by 7 or 8 inches broad, will be constructed in
2i hours, and in five or six days the hive will be half
filled.
The wax thus produced is more or less yellow in
colour, and has an odour resembling that of honey.
The beautiful geometrical form in which it is arranged
in the honeycomb is well known. When the wax has
served its purpose in the domestic economy of the hive,
it is collected for manufacturing purposes, by first
allowing the honey to drain off, or to be pressed out,
and then boiling the combs in water,with frequent stir-
ring, that the wax may not burn. In this way the combs
are completely melted, and the liquid is then poured
through hair-bags, which are pressed as long as any
wax continues to pass through. The sediment re-
maining in the bags is also boiled over again, and
more wax extracted from it. During the operation,

the wax from each bag is received in a vessel of cold
water placed beneath it, and answering the double
purpose of cooling the wax, and preventing it from
sticking. The wax is melted a second and a third
time, and passed through bags of increasing fineness
on each occasion. Lastly, it is melted once more
without water, and poured into pans or moulds wider
at the top than at the bottom, and wetted with cold
water to prevent sticking. The conical shape of the
cake thus produced is advantageous in two ways;
it is more easily disengaged from the pan, and it has
all its sediment or dross collected into a small space
at the under surface, and there is consequently less
waste in removing it. The moulds are kept in a
warm room until the wax has solidified, otherwise the
cakes are apt to crack across the middle. This me-
thod, though commonly employed, is tedious, eon-
sumes much firing, and wastes a considerable amount
of wax; for these successive meltings and removal of
dross cannot be effected without loss. Attempts have
been made to expedite the process; and those of
Mr. Bagster 1 recommend themselves by their simpli-
city. This gentleman gives directions for obtaining
a marketable wax from the ‘combs by a single opera—
tion, without either straining or pressing, in the follow—
ing manner. In an earthen vessel, much narrower at
bottom than at top, is placed water and aqzmfo'rz‘z's, in
the proportion of 1 ounce of the latter to every quart
of the former. When these are well blended, as
many good wax-combs are put in as will reach, when
melted, to within a finger’s length of the top of the
pan. The pan is then set on a clear fire, and stirred
while the wax is melting, and until it has boiled long
enough to liquefy the whole completely. It is then
removed from the fire, and allowed to cool gradually.
The wax then forms into a cake at the top, and the
impurities are underneath: these arrange themselves
in two layers, the lowest of which consists almost en-
tirely of dross, but the next contains a certain amount
of wax. When the cake of wax is turned out of the
pan, both these drossy layers are removed, leaving the
cake pure ; but the upper drossy layer is boiled over
again with more combs, and with any scrapings which
it may have been necessary to make from the upper
surface of the wax in order to leave it quite free from
extraneous matters. Old combs that have wax in
them, or other descriptions of refuse that have been
pressed, but yet retain a considerable portion of wax,
are pressed down in a close tub or vessel in a house
for five weeks. This causes the impurities to ferment
and rot, without affecting the wax, which may then be
treated as above described, and will yield a fine yellow
wax, little inferior to that of the best combs. Where
very great purity is required, the best empty virgin
combs are put into the same kind of vessel employed
in the preceding process, but with only a quarter of a
pint of water, to keep the wax from burning. The
pan is then set over a clear fire, and stirred until it
boils. At this time a clear yellow froth begins to rise

(1) “ The Management of Bees.” By Samuel Bagster, jun.
London, 1834.
WAX.
951
up, which froth is to be skimmed off into a pan placed
close at hand. The fire must be so managed that this
froth shall continue to rise without boiling over, and
a succession of skimmings are thus obtained, which
form a very pure description of wax. When no
more froth will rise, the residue is turned out into a
vessel of cold water, and can be boiled up again with
other combs. This method is only available with fine
combs.
By the above processes, bees-wax is freed from im-
purities, but is not deprived of its natural yellow
colour. For the greater number of uses to which the
substance is appropriated, it is, however, necessary
that the wax should be rendered perfectly white.
This is effected by exposing it in thin ribands 011 a
bleaching ground, where it is subjected to the action
of light, air, and moisture, and loses both colour and
odour. On a large scale, wax is purified and bleached
by first melting it with hot water or steam in a large
vessel of tinned copper or wood, letting it settle, and
then running ed the clear wax while still liquid into
a trough perforated at the bottom with a line of
holes, through which the wax passes, and falls upon
revolving wooden cylinders beneath, which are half
immersed in water, and by their action form the wax
into thin films or ribands. These films are placed
upon long webs of canvas, raised from the ground,
and exposed in an open field to the action of the
weather; their only covering being a thin netting,
which prevents their being blown away by the wind,
but does not hinder the free action of the air and sun
upon them. They are occasionally watered, if the
weather be dry; and if one or two operations do not
suffice, the bleaching process is repeated until the
effect is gained. Sometimes the colour seems obsti-
nately permanent, and the whole of the wax has to
be collected, remelted, and passed over the wet cy-
linders, so as to obtain new films, with fresh surfaces
to be acted upon. The bleaching process is much
more quickly accomplished by means of chlorine; but
wax thus whitened does not burn well, owing to a
portion of chlorine which remains in it combining
with a portion of the hydrogen of the wax, and form-
ing muriatie acid, which escapes in vapour into the
room. Another method of expediting the work is,
to add to 1 pound of melted wax 2 ounces of pul—
verised nitrate of soda, and then to stir in by degrees
1 ounce of sulphuric acid, diluted with 9 ounces of
water, keeping the mixture warm all the while.
When all the acid is added, it is allowed partially to
cool, and the vessel is then filled up with boiling
water and set aside. The cake of wax, when cold, is
put into boiling water, in order to remove all traces of
sulphate of soda and of acid: it is then white, and
should be perfectly free from nitric acid, which, if
present, would render it liable to become yellow.
Bleached wax contains less carbon and more oxygen
than yellow wax. It is translucent in thin slices, in-
soluble in water, and varies in specific gravity from
0 960 to 0966. At a temperature of 85°, it admits
of being kneaded; and at 150°, it fuses. When
heated with boiling alcohol, it is separable into two

principal substances of variable proportions, which are
Mg/rz'cz'ae, almost insoluble in boiling alcohol, and
which appears as a greyish white substance, without
any crystalline texture; and Carine, which in its
purest form is deposited from the alcoholic liquor, in
delicate needle-like crystals. A third substance,
called Cerolez'rzc, is found to remain in solution in the
alcohol when it has become cool. When subjected
to dry distillation, the bleached wax evolves margaric
acid, and a crystallizable substance, analogous in its
composition and physical properties to parafi'ine.
Certain liquid hydrocarbons, olefiant gas, and carbonic
acid, are at the same time evolved. The distilled pro-
duct concretes into a buttery mass, and contains no
sebacic acid. On distillation with lime, a quantity of
the erystallizable substance just referred to is
obtained, together with yellow oils of complex com-
position.
Chemists are not agreed in their application of the
term wax to various substances which possess waxy
properties; but those named in the following table
are often quoted as such. The composition of these
substances is said to vary in the'same way as that of
the fat acids, and they appear to pass into each other
by the addition of C2112; as in the following for-
mulae :--
Bees C,,H,,O,,
Chinese wax ..
Palm wax C°>°Hsfioi
Oxidised Chinese wax C,,,,,FI,,,O3
Myrtle wax CMHMO5
Cerosine................................. (MAJ-1,302
Cerosinic acid CHHMO3
In all the varieties of wax (with the exception of
that of the cork-tree), the atomic relation of the
carbon to the hydrogen is 1 :1.
The above substances, as obtained from the vege-
table world, are of far less importance than the pro-
duct of the bee, yet they are deserving of notice.
Several species of myrtle (Mg/rim) yield the product
called Myrtle-wax. This is especially obtained from
Myriam ceryem, which flourishes in Louisiana, the
berries of which are incrusted with wax. By boiling
these in water, a quantity of hard brittle wax of a
pale green colour is obtained, of the specific gravity
1015, the fusing point being 110°. A somewhat
similar wax is obtained from Mg/rz'ca cordqfolz'a, a shrub
which grows at the Cape of Good Hope. The stems
and leaves of palm-trees also secrete the substance
called Palm-20m. Such is the hard brittle greenish
yellow wax which we obtain from Rio de Janeiro. It
is soluble in boiling alcohol and ether; it fuses at
about 160°. A white and crystalline wax, resembling
spermaeeti, is obtained from a kind of sumach, Rims
succea’aaeum, and is known in commerce as O'lzz'acse or
Japan was". It is soluble in naphtha, but scarcely so
in alcohol and in boiling ether. It forms a soluble
soap when boiled in a solution of caustic potash. 1t
fuses at about 180°. Another wax, having the same
fusing point, is found upon a hard and ligneous va-
riety of the sugar-cane, and is known as sugar-cane
was and cerosz'ae. This is soluble in boiling alcohol.
but sparingly so in boiling ether. By boiling the bark
952
WEAR-WEAVING.
of the cork-tree, Qaeraus suéer, in alcohol, and distil-
ling off the alcohol, a quantity of yellow crystals are
obtained which form earls-tree wax, which may be
purified by repeated solution and crystallization.
Nitric acid converts this substance into a peculiar
acid, called cerz'm'c acid.
The demand for wax is great in Roman Catholic
countries, where gigantic candles of this substance are
required for the service of the severalaltars 5 but the
great improvement in the manufacture of composite
candles has reduced the demand for wax candles as
an article of domestic use. For the manufacture of
wax candles and tapers, see CANDLE.
The amount of wax produced in this country is very
large, but a considerable quantity is likewise imported
from abroad. In 1840, nearly 4,000 cwts. were im-
ported from the western coast of Africa, nearly
2,000 cwts. from Tripoli, Tunis, &c., and more than
1,000 cwts. from the East India Company’s territo-
ries. This was at a time when the very heavy duty
of 108. per cwt. was laid upon this article. In 1842,
the duty was reduced to ls. and 28. the cm‘. The
adulteration of this substance was great during the
existence of the heavy duties, and is still practised to
a less extent. The adulterants of yellow wax are
earth, pea-meal, resin, &c. Those of white wax are
white oxide of lead, white tallow, and potato-starch.
Oxide of lead may be detected by simply melting the
wax in water, when the oxide falls to the bottom;
tallow is discovered by the dull opaque white which it
gives to the wax, and starch is detected by means of
sulphuric acid, which carbonizes the starch without
acting on the wax.
WEAR, a dam, also called a weir, formed across
a river for maintaining its waters at a level necessary
for its navigation. It is also used for directing the
water towards a mill, and likewise for taking fish.
WEAVING is the art of combining threads, yarns,
filaments, or strips of different materials, so as to
form a kind of cloth or textile fabric. This art has
its origin in the necessities of man’s nature; the
rudest nations have practised, and continue to prac-
tise it, and the most refined nations have received
from the rudest the principles of the art, on which
they have engrafted improved details and mechanism.
The fibrous parts of plants, together with rushes,
straws, and grasses, woven into a kind of matting,
form the simplest kind of weaving, and probably pre-
ceded the art of spinning or twisting the material into
yarn, and doubling the continuous lengths of yarn
into thread, preparatory to weaving. The spinning
of fibrous materials into continuous lengths is referred
to by the inspired writer as an invention suggested
by a higher power than human, at an early period of
the world’s history. Moses declares (Exod. xxxv.
25), that “ all the women that were wisehearted did
spin with their hands.” We also learn from the same
chapter (verse 35), that weaving was practised by
those whom the Almighty had “filled with wisdom
of heart to work all manner of work of the engraver,
and of the cunning workman, and of the embroiderer
in blue, in purple, in scarlet, and in fine linen, and of

the weaver, even of them that do any work, and of
those that devise a cunning work.”
The Egyptians became celebrated at an early period
of the world’s history for their woven fabrics. Al-
though the looms depicted on the tombs at Thebes
are rude in construction, the fabrics produced by
their means were of a fine and costly character, as, at
the present day, the exquisite muslins of the Hindoo
workmen are produced by rude and apparently in—
efficient machines. Specimens of the skill of the
ancient Egyptian weaver have been preserved to us
in the cloths in which the Egyptians were accustomed
to wrap their mummies. Mr. Thomson describes
some mummy cloth, examined by him, as being beau-
tiful in texture and peculiar in structure. “ It was
free from gum, or resin, or impregnation of any kind,
and had evidently been originally white. It was close
and firm, yet very elastic. The yarn of both warp
and woof was remarkably even and well spun. The
thread of the warp was double, consisting of two fine
threads twisted together: the woof was single. The
warp contained 90 threads in an inch; the woof or
weft only 414. The fineness of these materials, esti-
mated after the manner of cotton yarn, was about 30
hanks in the pound. The subsequent examination
of a great variety of mummy-cloths showed, that the
disparity between the warp and woof belonged to the
system of manufacture, and that the warp generally
had twice or thrice, and not seldom 4h times,the num-
ber of threads in an inch that the woof had. Thus,
a cloth containing 80 threads of warp in the inch, of
a fineness about 24 hanks to the pound, had 40
threads in the woof ; another, with 120 threads of
warp of 30 hanks, had 40; and a third specimen,
only 30 threads in the woof. They have each re-
spectively double, treble, and quadruple the number
of threads in the warp that they have in the woof.
This structure, so different from modern cloth, which
has the proportions so nearly equal, originated pro—
bably in the difficulty and tediousness of getting in
the woof when the shuttle was thrown by hand, which
is the practice in India at the present day, and which
there are weavers still living old enough to remem-
her was the universal practice in this country.”
Mummy-cloths were of linen, the finest of which ap-
peared to have been made of yarn of nearly 100
hanks to the pound, with 14,0 threads in the inch in
the warp, and about 64 in the weft. Striped and
dyed goods were also made, indigo being used as one
of the dyes. Herodotus speaks of it, as a peculiarity
among the Egyptians, that the men wove. Some of
the ancient looms were horizontal, others vertical; in
the latter case, the weft was driven upwards, with a
shuttle about g‘; a yard in length.
The productions of the loom, among the ancient
Greeks and Romans, would probably rival in beauty
and variety the damasks, shawls, and tapestries of
modern art, and their patterns frequently represented
mythological subjects. The art of weaving formed
not only a distinct trade, but it was also a domestic
employment, wool being the chief material woven.
Minerva was the patron saint of the art, and she was
WEAVIN G.
953
regarded as the friend of industry, sobriety, and fe-
male decorum. The work was chiefly performed by
female slaves, under the direction of the mistress of
the house, who with her daughters assisted therein,
instructed beginners, and finished the ornamental
parts. During the early ages, females in Europe
were the chief weavers; and as the preparation for
the loom, or spinning the yarn, was chiefly performed
by girls and young unmarried women, they were
called spinslers, a term which is still retained. About
the 41th century, men began to practise weaving, a
circumstance which St. Chrysostom deplores as a
mark of the prevailing sloth and efl'eminacy among
men. Some of the more opulent heathen temples
kept an establishment of female weavers, for supply-
ing the shawls and furniture used in the religious
rites. Young females of the highest rank were some-
times selected for weaving the shawls used in some of
the processions. Among the ancients, striped goods
were produced by making the warp threads alternately
white and black, or of different colours of a different
series, according to a prescribed pattern. The Greeks
were acquainted with the mode of mounting the loom,
or arranging a number of strings, so as to separate
the warp threads into two or more groups, between
which the weft was passed; the leash, pi'ros‘, being
one such string, and a woven pattern was termed
CffLI/T'OS‘, 'rpi'juwos, or vrohiipwror, according as it C011-
tained two, three, or more groups of strings, or, in
the language of modern weaving, leaves of lzealcls or
lzerlrlles. Variegated patterns were also produced by
using warp threads of one colour, and weft threads
of different colours, changed at regular intervals.
Checked and striped goods may have been first pro-
duced by combining the natural varieties of wool,
such as white, black, brown, 850. Most of the other
varieties, in appearance and quality, were produced
by means of the weft, the warp being more twisted,
and therefore stronger and firmer than the weft. The
warp and the weft were spun from different kinds of
wool, and after the piece had been woven, the fuller
carded out the nap. Rich and ornamented materials,
introduced into the fabric, were made to form part of
the weft, as in the “ vestis subserica,” where the weft
was of silk ; in other cases it was of gold, or of wool,
dyed with Tyrian purple, or of beaver’s fur.1
The ancient mode of weaving among oriental na-
tions is illustrated by the loom of the modern Hindoo
weaver. It consists of two bamboo rollers, one for
the warp, the other for the woven cloth, and a pair
of healds for parting the weft. The shuttle is similar
to a large knitting-needle, and is somewhat longer
than the breadth of the cloth; it is also used as a lazy
or bnllen for driving home the weft threads. The
weaver erects this rude apparatus under the shade of
a tree, forms his seat by digging a hole for his legs,
in which are also placed the lreadles; he stretches his
warp by fastening, by means of pins in the turf, two

(1) For further information respecting the art of weaving among
the ancients, we must refer to Mr. Yates’s “ Textrinum Anti-
quorum ;” and also to Professor Smith's “ Dictionary of Greek
and Roman Antiquities,” article Tela.

bamboo rollers, at the proper distances apart; he
attaches the heddles to a branch of the tree over-
head, or to a bamboo rod extended between two trees;
and taking his seat at the edge of the hole, he inserts
the great-toe of each foot into a loop, which serves
for a treadle ; and thus, raising the alternate threads
of the warp, he draws the weft, and strikes it close
up to the web with his long shuttle. The warp is
previously dressed, by means of rice-water. The weaver
is assisted by a pirn-winder, whose duty it is to
supply weft, mend broken threads, &c. The method
of warping is to fix sticks in the ground at certain
distances, and to lead round them the yarn pre-
viously wound upon pieces of split bamboo, attached
to a centre stick held in the hand. The yarn is spun
by women by means of the distaff.
The art of weaving gradually spread from the East
to the West. The time of its introduction into Britain
is uncertain. It was practised for several centuries
as a domestic employment, and ceased to be such
when the factory system with automatic-machines and
steam-power were found sufficient in a single mill to
perform the work of many thousands of human hands.
SECTION L—VARIETIES or Wnxvrne.
In a piece of woven cloth, two distinct sets of
yarns or threads are to be distinguished; these tra-
verse the web in different directions, usually at right
angles to each other. The threads which form the
length of the web are called the warp-threads, or
simply the warp. The thread which runs across the
cloth is called the writ‘ or woof; and may be regarded
as one unbroken thread, passed alternately over and
under each thread of the warp, until it arrives at the
outside one, when, passing round and under that, it
returns back over and under the threads to the outer
thread at the other side or edge; passing over those
yarns when proceeding in one direction, and passing
under them when in the opposite direction, by which
means the warp-threads are closely woven together.
This constitutes what is called plain weaving. Fig.
2302 represents the appearance of a piece of plain

=1‘ ‘ ..
aaasaaaa
J'F'il-i' h"?!-
WWW“
Fig. 2302. rnam-wzavrzve.
cloth seen through a microscope: the alternate in-
tersections of the threads are shown in the lower
figure.
In mill or z‘weel (from the French tonaz'lle), which
comprises an extensive variety of woven fabrics, such
as satin, bombnzeen, lrerseynzere, the threads of the
warp and woof do not cross each other alternately,
but only the third, fourth, fifth, sixth, &c., cross each
95d
WEAVING.
other. Fig. 2303 is an enlarged representation of a
piece of tweeled cloth, by which it will be seen, in
this specimen, that the same thread of weft is fins/zeal
III" Inn-maul-
Jesters-as: ism - ill."


TWEELED~WEAV1NG-
Fig. 2303.
or separated from the warp, while passing over 3
threads, and is held down while passing under the
fourth. A cloth of this kind turned on the other
side would present the same appearance in the warp,
every fourth thread appearing to be interwoven with
the weft, and the remaining three threads flushed.
In twilled fabrics, the point where the threads of the
warp cross each other form diagonal lines, parallel to
each other, across the face of the cloth, the degree of
obliquity varying with the number of warp threads
flushed. In the coarsest or Mantel-twill, every third
thread is crossed. In finer fabrics, the threads inter—
sect each other at intervals of 4!, 5, 6, '7, or 8 threads;
in some silk stuffs, as in fall satin twill, there is an
interval of 15 threads. In weaving twills, the loom
is mounted in a peculiar manner. In plain-weaving,
the warp threads are passed through 2 healds, one
heald raising every other thread of the warp, in order
to admit the shuttle; but in twilled cloth, there is a
number of healds equal to the number of threads con-
tained in the interval between two intersections of
the warp and weft. Thus, when every third thread is
to be interwoven, three leaves are required; if every
sixth thread, six leaves, and so on; hence twills are
distinguished by the number of leaves required in
weaving them, as a fiance-leaf twill, a four—leaf lwili,
and so on. Twills are frequently used by the silk-
weaver for the display of colour, and also for the sake
of strength, thickness, and durability. In fabrics,
where the threads cross each other at distant inter-
vals, there are fewer deviations from the right line,
and, consequently, less liability to chafe and to wear.
By this method, also, a larger quantity of materials can
be collected into the same space than in plain weav-
ing, and this of course gives greater durability.
Pile-weaning. In addition to the usual warp and
weft threads, a third thread is introduced in the
course of the weaving, and is thrown into loops by
being woven over wires of the breadth of the cloth.
In the Brussels-carpet‘ these wires are simply drawn
out, and the loops left standing; but in the Wilton-


STRUCTURE OF VELVET.
Fig. 2304.
carpet they are cut out, by passing a sharp knife along
a groove in their upper surface. In this way a nap

or pile is formed, as in the various kinds of velvet, nel-
neleen, fnsliwn, the See Fig. 230i.
Figure-weaning consists in ornamenting the cloth
with figures, flowers, and other devices, for which
purpose the warp is divided among a number of
healds, which can be lowered at pleasure by separate
treadles, while threads of different colours may be
concealed or brought up to the face, or made to
change places, according to a prescribed order. In
figure-weaving, the draw-loom or the Jncqnnml appa—
mlns is used.
Gauze-weaning. The essential feature of this style
of weaving is, that between every two casts of the
shuttle, the warp threads, are made to cross each
other, so that the weft threads, represented by black


Fig. 2305.
GAUZE-WEAVING.
dots in Fig. 2305, are separated from each other,
and a light transparent texture produced.
Lace-weaving. In this variety the threads of the
weft are twisted round those of the warp, as in Fig.
2306. The term net is applied to a large nmnber of
light cross-woven goods, and, according to the mode
in which the threads cross each other, we get w/iip-
nel, mail-nel, pnllw‘n-nei, dronnei, spider-nel, balloon-
nel, Paris-nel, 850. These varieties of net were for-


Fig. 2306.
LACE—WEAVING.
merly produced at the loom with warp threads
stretched horizontally, and weft threads thrown in
by a shuttle. Bobbiwnel is produced by a self—acting
machine of peculiar structure.
Knz'li‘ing, or stocking-weaning. Knitting is a kind
of weaving adapted to the production of small articles,
and it differs from the foregoing varieties, in the cir—
cumstance that only one thread is employed for warp
and weft. The thread is passed in each stitch, first
in that of the weft, then in that of the warp, so as to
form successive rows of loops, the loops of each row
being drawn through those of a former row. In
stocking-knitting, the whole fabric consists of one
continuous thread.
Banning is a kind of weaving on a small scale, per-
formed with one thread, with the assistance of the
needle; it is used for filling up a hole in a woven
fabric.
Nailing. In netting, the threads or cords are tied
into hard knots at their points of intersection, so as
to form mes/tea, which always continue of the same
slze.
SECTION II.--ON PLAIN Wnavme.
In a piece of plain cloth, as already noticed, the
threads which proceed in the direction of the length
are called the warp; also the twist‘, the mine (from
the French la alanine, or the chain), and also organ-
zine. The threads which run in the direction of the
width of the cloth are called the weft‘; also the woof;
the slzool, and the lawn. Plain weaving, where the
WEAVING.
955
weft threads pass alternately over and under those of
the warp, is performed at a Zoom, of which the essen-
tial parts are—1st, an arrangement for stretching
the warp; 2d, a contrivance for raising every alter—
nate thread, or half the threads of the warp, and
depressing the other half, so as to open a space or sized
for the shuttle which carries the weft; 3d, a contri-
vance for striking each weft thread close up to the
one previously thrown.
The frame of the loom consists of four upright
posts, connected by cross beams at the top and bot-
tom. At one end is the beam or yarn roll, 13, Fig.
2307, on which the warp threads are wound, and at
the other end, is the cloth-beam, c, on which the cloth
is wound as it is finished. In turning round the
beam 0, fresh portions of the warp are wound off
from n ; and in order to keep the yarn threads ex-


Fig. 2307. THE COMMON Loo.
tended, weights W20 are hung by cords to the warp-
beam, or a large stone may be slung over it. The
extended threads of the warp are prevented from
becoming entangled by fiat rods, 7* r, placed between
the alternate threads. The lzealcls or lzeddles, fr, it’, by
which the threads of the warp are alternately raised
or depressed, consist of a number of twines, with
loops in the middle, through which the warp threads
(‘I D are drawn. The
E two healds are
united by a cord 8,
passing over a
pulley 1), (collec-
tively called the
harness) so that by
lowering one heald,
the other rises. The
warp threads are
also passed through
LEE!
Ififgfifihfij
\"‘i\/d the deeds or teeth
Fiy-2368- of a reed, set in a
movable swing—frame L, called the Zat/ze, lay, or cat‘-
ten; shown separately in Fig. 2308, the last term re-
ferring to its action in batting or beating home the

weft to the web. The bottom of this frame is fur-
nished with a sort of shelf, called the shuttle-race,
along which is thrown the shuttle, (two forms of
which are shown in Figs. 2309, 2310. The shuttle is
a small boat—shaped piece of wood, sometimes moving
on wheels, and hollowed in the middle for contain-






‘I' 1m
a,llllllltlllhlllllllllhlW ,a


Fig. 2310. Fig. 2311.
ing the cop of yarn which forms the weft. A small
hole at the side of the shuttle allows the weft yarn to
run out with the motion of the shuttle. The shuttle
may be thrown by hand, or by means of the fly. By
the latter method the two ends of the shuttle-race are
closed, so as to form a trough, shown separately in
Fig. 2311, in which two pieces of wood, called pic/ters
or P60k87‘8, are made to move along wires, as shown in
Fig. 2308. A string from each picker is attached to a
handle, as shown in the same figure, which the weaver
holds in his right-hand; and it is thus easy for him, by
means of a smart jerk, to project the shuttle along
the shuttle-race from right to left, or from left to right.
The weaver occupies the seat s, Fig. 2307, and press-
ing with one foot on one of the treadles T, he lowers
one of the healds, the efiect of which is to lower all
the alternate threads of the warp passing through the
loops; the other heald will of course be simultaneously
raised, thus forming a shed for the passage of the
shuttle. The shuttle is now thrown across the open-
ing thus formed, by which means a thread of weft is
stretched across the web, and this is driven close up
to the web, by means of the batten, which the driver
guides with his left hand. The weaver raises his foot
from the treadle T’, and presses down with the other
foot the treadle T,-—the effect of which is to depress
the alternate threads which before were raised, and
to raise those which were before depressed. The
shuttle is again thrown, whereby another thread of
weft is drawn across the web; this is driven home by
means of the batten; the treadle Tis again depressed,
and thus the work proceeds with great rapidity.
When a few inches of cloth are woven, they are wound
on the cloth-beam c by turning a handle at the side,
a ratchet-wheel preventing the beam from slipping;
but as the weaver must always have a certain length
of woven cloth before him, not wound upon the cloth—
beam, this would tend to contract in breadth by the
contraction of the warp, were it not prevented by


Fig. 2312.
some contrivance. For this purpose, two pieces of
hard wood called z‘emples, Fig. 2312, are used. Their
ends are furnished with sharp points, which pierce the
edge or selvagc of the cloth on each side, and thus
956
WEAVING.
keep it distended by adjusting the two pieces of wood
as shown in the figure.
Plain weaving is not a dificult operation. The
treadles must not be depressed too suddenly, or some
of the warp threads will be broken, and much time
be lost in mending them, before the weaving can he
proceeded with. The shuttle must not be thrown
with too much force, or it will recoil, and, by slacken-
ing the weft thread, injure the appearance of the
web. The batten must also be brought forward
against the shoot with an equal degree of force at
every blow, or the cloth will not be uniform in thick-
ness; and this force must vary with different fabrics
and degrees of fineness. The loom should be mounted
so that the range or swing of the batten may be pro-
portioned to the texture of the goods. The greater
the arc of the circle in which the batten swings, the
greater the degree of force with which the shoot is
driven home. Hence, the woven cloth should be fre-
quently taken up on the cloth—roll, or the uniformity
of its texture may be interrupted by the diminished
range of the batten. For coarse or thick goods, the
batten should be hung so as to have greater play,
and consequently more force, than for fine and light
fabrics.
The various processes of weaving are always more
intelligible when the construction and action of the
common loom are well understood. Hence we have
introduced the description thereof thus early. Before,
however, the weaver can be set to work, a number
of complicated processes are necessary for the prepa-
ration of the yarn or thread, and for the mounting of
his loom. These processes we now proceed to de—
scribe under their respective heads.
Warping—The yarns or threads used in weaving,
although of the same material, differ in hardness, or
amount of twist, according as they are destined for
the warp or for the weft; the harder and more twisted
yarns being used for the warp, and the softer or less
twisted for the weft. The yarn or thread is supplied
by the spinning or doubling-mills in hanks, skeins, or
cops. [See Corron] The warp threads are wound
on bobbins, from which the warp is formed by a pro-
cess termed warping, the object of which is to place
the threads alongside of each other in one plane. In
some woven fabrics, upwards of 8,000 threads have
thus to be placed side by side without entanglement
or confusion. The old method, still practised in
India and China, was to draw out the warp to its full
length in an open field. One of the earliest of our
factory contrivances is the warping-frame, consisting
of two upright sides, containing a number of wooden
or iron pins, between which the yarns are extended.
The bobbins of yarns are contained in a frame, and
the warper, tying all the ends of the yarns together,
attaches them to one of the pins; then gathering
all the threads into her hands in one clue, and allow-
ing them to slip through her fingers, she walks to
the other end of the frame, and passes the yarns
over and round one of the pins, repeating this opera-
tion backwards and forwards until enough yarn has
been collected to form the warp.

The usual method of laying out the warp, is by means
of the warping-mill, Fig.23l 3, which consists of a large
wooden skeleton-reel or frame, with 12 or more sides
of determinate length, which serve as a measure for
the total length of the warp. The frame is mounted
on a vertical axis, and is moved round by means of
an endless band, which connects the bottom of the
axis with a wheel under the control of the viarper.
One-sixth of the whole number of bobbins of yarn
required to form the warp is mounted in a frame
called a zfmeers, the bobbins being set loosely upon
iron skewers so as to revolve and give off the yarn
freely. The yarns or threads are passed through



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Fag. 2313. wAaPInG-MILL.
an instrument called a jack, or deck-60:11, placed be-
tween the bobbins and the frame, and made to slide
up and down between two upright posts; it is sus-
pended by a cord, which passes over a pulley, and is
secured to the top of the axle, so that as the reel
revolves a portion of cord is wound on the axis, and
thus the heck is slowly raised from the bottom to the
top ; when the mill is turned in the reverse direction,
the heck descends by its own weight. The heck divides
the warp threads into the Zeus, or two alternate sets,
one set for each heald ; for which purpose the heck—
block contains 20 or more steel pins, with an eye in
the upper end of each, through which
a warp thread is passed. The pins
are mounted alternately, so that
either may be raised as required.
See Fig. 281d. When the threads
are passed through the eyes of the
heck, their extremities are knotted
together, and fixed to a pin on the
warping- mill. The mill is then turned slowly round,
until the top of these pins comes nearly opposite the
heck. The warper then lifts half of the heck-
frame, and, passing the forefinger of the left hand
through one space formed between the threads,
and his thumb through the other space, places the
yarn upon 2 pins of the warping—mill; the first pin
passing through the interval kept by the finger, and


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mmsx‘umlsmmw
U.‘ I
Fig. 231%.
WEAVIN G.
957
the second through that made by the thumb, by which
means every alternate thread is crossed, and the lea is
formed. The warp is made to describe a spiral line
over the frame, and at the bottom the threads are
once more passed over pins. The mill is then made
to revolve in a contrary direction, and the warp is
made to describe another spiral line from the bottom
to the top. The operation is repeated from the top
to the bottom, and so on until a suflicient length of
yarn is obtained. The leas, or crossing of the threads,
is now preserved by tying a hand through them at the
top and bottom; the warp is then removed from the
mill by taking it from the lower pins, and winding it
upon a stick, or upon the left hand of the warper,
into a large ball. A cotton warp may vary from 400
to 600 yards in length. Care must be taken in
warping to avoid broken threads, or to mend them as
soon as they are broken.
Beamiizy.--The next operation is to spread out
the warp of yarns upon the yarn-beam of the loom.
For this purpose the iron pivots of the beam rest
in a frame, and the beam itself is made to revolve,
by being connected with a revolving shaft. In
order to distribute the warp-threads uniformly over
the beam, in the order in which they were laid by
the warper, they are passed through a separator, or
ravel, which the weaver holds in his hand, consist-
ing of pieces of cane fixed to a rail of wood, so as to
form a rude kind of comb. The teeth of this ravel
spread out the warp on the beam to the required
length.
Dressing and Samar—As the warp threads in the
process of weaving are subjected to much tension and
friction, they require to be strengthened by a dressing
of glue, size, or paste. Cotton and linen yarns are
dressed with flour-paste, to which a little brine is
sometimes added, to prevent it drying too quickly,
and making the yarn brittle. The rollers containing
the cotton-yarn are mounted on a frame; the threads
are passed through a reed to keep them separate, and
then between 2 rollers covered with felt, one of which
dips into a trough of paste. The lower roller applies
the dressing to the yarn, and the other one squeezes
out the superfluous portion. The paste is worked
into the fibres by means of cylindrical brushes over
and under the warp, moving in a contrary direction
to that of the yarns. The dressed warp is dried by
being passed over a steam-chest, near which is a re-
volving fan for keeping up a current, and preventing
the air from becoming saturated with moisture. The
warp is then passed to the main beam of the loom,
over which it is regularly distributed by means of a
reed.
The Siziizg Machine, Fig. 2315, is also used for
dressing yarns. It consists of an iron trough,
furnished with the steam-jacket, and containing a
number of copper rollers arranged as in the figure,
over the surface of which the warp is made to travel.
The rollers revolve by the friction of the warp, which
is thus pressed flat upon them and remains free in
the spaces between them, by which means the fibres
become impregnated with fluid paste, with which the

trough is nearly filled. Two rods stretch along the
trough along either side of the warp, in order to keep
it in the centre of the rollers. The warp passes out
of the trough be- 7 . _
tween two large “
wooden rollers, M p,
which press Out
Ifi
the superfluous i

paste. The warp k1.’ kg“:
is then dried b f’fi‘i {’
- y ‘ , that at being passed ‘I: k . , i. 3 kn‘ \
over hot cylin Q 'J’" is] o
i ' (is n
ders, or through a
the air of a hot
room. Glue is
commonly used in the sizing of woollen warps, for
which purpose the warp is passed through a trough
containing a gelatinous solution. One end of the
warp is passed through a trumpet-shaped hole, at one
end of the trough, then under a roller at the bottom,
along the trough to another roller, and then through
another trumpet-shaped opening at the other end of
the trough. It is pulled backwards and forwards
through and under these rollers, because it is found
that yarns and stuffs require to be alternately im-
mersed in a fluid and squeezed out in order to expel
the air entangled in the fibres; otherwise they are
not properly penetrated by the fluid. When the
woollen yarn is dry, a little tallow is smeared over it.
Worsted warps are scoured in soap-suds, in order
to get rid of the oil used in the process of combing
the long wool. On leaving the tub of soap-suds,
they are passed between pressing rollers; then Zia/zed
or plaited in a peculiar manner, to prevent the
entanglement of the warp threads, and also for the
sake of compactness. When wanted for use, each
bundle can be readily undone by pulling out one of
the ends.
Drawiizg-iia—When the warp has been regularly
wound on the warp beam, every yarn requires to be
drawn through the corresponding eye or loop of the
healds. This is called drawing-in. For this pur-
pose the yarn-beam is suspended by its ends, so as to
allow the warp to hang down in perpendicular threads;
the healds are also hung up near the warp ends. The
weaver, seated in front of the healds, with an assis—
tant on the other side, picks up every thread in order,
and delivers it so that the person on the opposite side
may draw it through by means of a small hook. The
order inwhich the threads are to be taken is indicated
by the leas-rods, every thread crossing the one next
to it. When the warp has been passed through the
eyes of the heald, it is drawn through the reed, two
threads being passed through each reed-split. The
leas-rods being in their proper places, the first thread
passes over the first rod, and under the second; the
second thread under the first, and over the second,
and so on alternately; by which contrivance each
thread is kept distinct, and, should it break in the
loom, its place can easily be found. A third rod
divides the warp into split/‘ails, two threads passing
alternately over and under it. As the work proceeds,
Fig. 2315.
958
WEAVIN G.
small portions of the warp are knotted together; and
the drawing-in being finished, the yarn threads are
knotted to strings attached to the warp-beam ready
for stretching in the loom. The dents of the reed
must be very regular and even, or the warp threads
are likely to break, and the texture of the woven
fabric liable to irregularity. The number of dents in
a reed of a given length, or, as the weaver terms it
the number or set of tire reed, determines the fineness
of the cloth, two threads passing through each dent.
The set of the reed varies in different places. Thus,
a (SO-reed cloth at Blackburn does not indicate the
same degree of fineness as a (SO-reed cloth at Stock—
port; but the method of computation at Stockport is
the more simple, the fineness being estimated accord-
ing to the number of warp threads in an inch. A
Stockport 60-reeal cloth contains 60 warp threads in
an inch; a Blackburn, a Bolton, and a Scotch ITO-reed
all vary in fineness with the set of the reed.
When the cloth is woven, it undergoes a variety
of finishing processes, varying with its material, an
account of which will be found under BLEACHING
— GALENDERING —— CALICO—PRINTING -- Drnrne -—
WOOL, &c.
Sncrron III—ON PATTERN on FIeUnE-wmvnve.
Uniformity of texture is produced by the warp and
the weft threads being of equal fineness, while the tex-
ture itself depends on the fineness of the yarn and
the set of the reed. Yarns of different degrees of fine-
ness, introduced at intervals into the web, will give two
distinct textures, producing a sort of striped pattern,
which admits of much variety. When the warp
threads are of one colour, and the weft of another,
a slim,‘ pattern is produced, the loom being arranged
as in plain weaving. In striped patterns, the stripes
may be arranged by the warper, who introduces at
regular intervals the coloured threads required to
make the stripe. Variety is also produced by em-
ploying yarns of the same colour, but of different
degrees of fineness; or by drawing a larger number
of warp threads through some of the eyes of the
heald than others. Thus, two or more threads may
be passed through the same eye of the heald, or three
or more healdfulls through the same intervals of the
reed; or, with fixed stripes both methods may be
employed. When stripes extend across the cloth,
they are thrown with the weft, the weaver employing
shuttles containing coloured threads, which are used
at proper intervals.
Glace/rs are formed by combining the two methods
of striping. The warper first produces an alternation
of colours in the warp, by inserting coloured threads
at certain times; and the weaver produces a further
alternation by throwing in wefts of different colours
from one or more shuttles. Stripes and checks are
largely manufactured in worsted, in silk, in cotton,
and other materials. When the pattern of checks
is different at the borders from that at the middle or
bosom of the web, they are called shawls and handker-
chiefs. Twills, or needs, have been noticed in Sec-
tion I.

Figure-weam'ny requires considerable preparation in
mounting the loom, and differs from plain-weaving in
the number and arrangement of the healds, and the
method of moving them. As the number of healds is
generally too great to be moved by the feet of the
weaver, an apparatus called the drawloom was in
general use until the introduction of the Jacquard
machine, and still continues in use in certain locali-
ties. In the drawloom, the warp threads are passed
through loops formed in strings, arranged in a vertical
plane, one string to every warp thread; and these
strings were so arranged in separate groups, that
when an attendant, called the drawboy, pulled the
handle which united one group, he drew up all those
warp threads which, in the order of the pattern, re-
quired to be raised for the passage of the shuttle.
The order in which the threads are grouped is deter-
mined by a pattern paper or design; it is divided by
lines into small squares, so as to represent a woven
fabric, and upon it the pattern is drawn and coloured.
It thus guides the weaver in building the “ monture,”
or arranging and grouping the various threads; and
the order in which the handles are to be pulled or
drawn is also arranged so that the weaver and his
drawboy may work with ease and certainty. Care,
however, is required not to pull the wrong handle, a
mistake likely to occur in so monotonous an employ-
ment. Such an accident would, of course, throw out
the whole pattern. Hence, a mechanical drawboy has
been contrived, consisting of a half wheel, with a rim
grooved so as to catch into the strings requiring to
be pulled down. This half wheel travels along a
tooth-bar, with an oscillating motion from right to
left, and draws down the particular cords required for
the pattern. The building of the monture was often
a work of some months, and then only served for one
pattern.
Jacquard, the inventor of the apparatus which has
caused his name to be so well known, was a straw-hat
manufacturer at Lyons. His attention was first di-
rected to the subject of mechanical invention by
seeing in a newspaper an offer of a reward for a
machine for making nets. He produced the machine,
but did not claim the reward. The circumstance
becoming known to some persons in authority in
Paris, Jacquard was sent for, introduced to Napoleon,
and was employed in correcting the defects of a
loom belonging to the state, on which large sums of
money had been expended. Jacquard stated that he
could produce the effects intended to be produced by
this loom by far simpler means. He was requested
to do so; and, improving on a model of Vaucanson,
he produced the apparatus which bears his name. He
returned to Lyons with a pension of 1,000 crowns;
but his invention was regarded with so much mistrust
and jealousy by the weavers, that they attempted to
suppress it by violent means. The “Conseil de
Prud’hommes,” who are appointed to watch over the
interests of the Lyonese trade, ordered his machine
to be broken up in the public place, and, to use the pa-
thetic expression of Jacquard himself, “the iron sold
for iron, the wood for wood, and he, its inventor, was
wnxvrne.
959
delivered over to universal ignominy.” Other coun-
tries, however, appreciated the invention, and had it
in successful operation, rivalling and even surpassing
the products of the French loom, before the Lyonese
weavers recognised their folly. The Jacquard appa-
nllatllfin soon get into general use, in the silk, worsted,
and muslin manufacturing districts of France and
England. The Jacgaa'rtl apparatus, or loom, as it is
sometimes called, is not really a loom, but only an
appendage to one: it is attached to its upper part in
a line with the healds, and its function is to raise the
warp threads in the order and number required for
the pattern for the passage of the shuttle. It has
been already stated, that in figure weaving, all the
warp threads which rise simultaneously have their
appropriate healds. In the drawloom, these were
raised by means of cords which connected them into
a system, which could be raised as required by the
pattern. In J acquard’s apparatus, the warp threads
are raised by a number of wires arranged in rows
and formed into hooks it it at the upper extremities,
as in Fig. 2316. These books are supported by bars,


Fzg. 2316.
a b the ends of which are represented by dots; and the
bars are supported by a frame,whieh is alternately raised
and lowered by a lever attached to and acting with the
treadle. If all the bars are raised at the same time,
all the warp threads will be elevated; but if some of
the hooks be pushed ofi' some of the bars while the
others are allowed to remain on, such warp threads
only will be raised as are connected with the engaged
hooks. Accordingly, there is a contrivance for dis-
engaging the books from the bars, and this is effected
by means of horizontal wires, 20 w, furnished with
loops in the centre, (shown separately in Fig. 2317),
ll
\f'rn E’)
Fig. 2317.
through which the lifting wires are made to pass.
These horizontal wires are kept in position by spiral
springs s 5 contained in a frame, and the points of the
wires 12 _71 protrude from the opposite side.
Now, it is evident, from an inspection of Fig. 2316,
that if the points of the wires be pressed by any force,
the wires will be driven into the frame, the hooked
wires passing through them will be disengaged from
the bars, and the warp-threads of the disengaged
wires will not be elevated. When the pressing force
is removed, the elasticity of the springs will drive the
needles forward, and restore the hooks to the bars
The method of driving back the wires is by means of

a revolving bar of wood, Fig. 2318, of 4! or more
sides, each side being pierced with holes, correspond-
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Fig. 2318.
ing in number and position with the points of the
needles. One of the sides of this bar is brought
up against the points of the wires every time either
treadle is depressed. If the side of this bar alone were
to be opposed to the points of the needle, the points
would simply enter the holes, and no effect be pro-
duced : but if some of the holes be stopped while others
be left open, the wires which touch the stepped holes
would evidently be driven back, and the hooks of the
vertical wires attached to them be disengaged from
the bars; while those which enter the holes would
remain undisturbed, and only the warp-threads at-
tached to their vertical wires would be raised. This
stoppage of some of the holes in each face of the re—
volving bar is effected by covering it with a card con-
taining holes corresponding with those in the bar, but
fewer in number; so that, when the points of the
wires come in contact with an unperforated part of
the card, they are driven back, but when the points
enter the holes of the card, the wires are not moved,
and, consequently, the books of the vertical wires
remain on their bars. By this contrivance the in-
tended pattern is made out. The revolving bar pre-
sents a new card to the points of the horizontal wires
at every quarter revolution, if the bar be 4F'Sid6d-
The holes in the cards being so arranged as to raise,
in succession, those healds which will make out the
intended pattern, it is necessary that there should be
as many cards as there are threads of weft. Where
the pattern is complicated, the number of cards is very
considerable. In some of those absurd attempts to
represent in one material forms and objects which are
easily and naturally delineated in another material,
such as the portrait of a man woven at the loom in-
stead of being painted at the ease], the number of cards
required is very considerable ; for example, the modern
Lyonese weavers, to atone for the ingratitude of their
ancestors to their illustrious countryman, resolved to
erect a monument to his memory; and the result was,
one of those extraordinaryn but very unnecessary
specimens of perverted ingenuity, a portrait of
Jacquard, woven in silk, representing him in his
workshop, surrounded by his implements, and plan-
ning the construction of the Jacquard apparatus. For
this “ Hommage,” as it was called, there were 1,000
threads in each square inch, in both warp and weft;
24,000 cards were required for the pattern, each card
being large enough to receive 1,050 holes. In the
Jacquard apparatus the cards are fastened together
by threads, so as to form a kind of endless chain, one
complete revolution of which makes out the pattern,
and by continually working this, the pattern may be
repeated several times in one warp.
960
WE AVI NG.
The preparation of the cards for the pattern is a
special employment, not undertaken by the weaver.
The pattern, on an enlarged scale, is first drawn upon
squared paper, as already noticed, and is then re-
peated in a frame containing a number of vertical
threads, corresponding with the warp of the fabric;
the workman then, with a very long needle, takes up
such threads as are intersected by the pattern, insert-
ing a cross thread under them, and carrying it over
all the remaining threads in the same line, repeating
the process until he has inserted a sufiicient number
of threads to make out the pattern. This being done,
the threads thus interlaced are attached to a card-
punching machine, which resembles in principle the
Jacquard apparatus, and is provided with lifting cords,
wires, and needles, connected, as in Fig. 2316, so
that, by pulling the lifting-cords, the wires or needles





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Fig. 2320.
will be protruded. In front of these needles, corre-1
sponding with the revolving bar, Fig. 2318, is a. thick
perforated iron or steel plate, each of the perforations
containing a movable steel punch, fitting easily into
the hole ; the protrusion of any of the needles drives
forward the punches which correspond with them,
and deposits them in a second similarly perforated iron
plate, fitting close to the face of the first. In order
that the steel punches may be properly protruded,
one end of each warp-thread is connected in succes—
sion with the separate lifting-cords of the machine;
each thread of the weft is then taken by the two ends
and drawn upwards, by which means all the Warp-
threads passed under by this weft-thread will be
raised, and can be collected together in the hand, by
pulling them; the lifting-cords to which they are
attached will cause the needles to protrude, and these
will drive out the cylindrical cutters from the per-
forations on the fixed plate into the corresponding
cavities of the movable plate. A blank card slip is
placed upon the latter, which is then removed to a
fly-press, and the punches are driven through the
card slip. The process is repeated on all the other
card slips required for the pattern, the various cards
being numbered and attached together in order. The
movable plate and the perforated card are represented
in Figs. 2319, 2320. The two outer large black spots
at each end of the plate are guide-holes corresponding
with those in the cards, and are used for tying the
various cards together. The other large spots, one
at each end of the card, fit into the conical projections
of the revolving bar, Fig. 2318. The set of cards
required for the production of a pattern is made up
into a bundle, with a numbered label, and a portion
of the fabric attached to it. In using the chain of

cards at the loom, they are arranged in several folds,
and are partly supported on a curved board. The
Jacquard apparatus has done much to extend the use
of figured fabrics, and is applied to various descrip-
tions of weaving. By its means the most beautiful
productions of the loom require not more than ordi-
nary skill on the part of the weaver, while the labour
of the weaving does not greatly exceed that required
for plain goods.
In the foregoing description we have been anxious
to convey a clear idea of the principle of the Jacquard
apparatus. The applications of this principle lead to
a great variety of apparatus which it is impossible to
describe in this place. We may, however, notice one
or two varieties of Jacquard apparatus in the Great
Exhibition. :——“ In Mr. Barlow’s double Jacquard
loom two cylinders are employed, and the cards are
disposed upon these in alternate order, so that while
one cylinder with its cards is brought into action
upon the horizontal wires, the other is withdrawn for
the purpose of rotating it and shifting the card, and
vice oersa’. By this arrangement the loom can be
worked with a velocity “40 per cent. greater than that
of the ordinary construction. The steadiness of its
action is greatly increased, and the strain upon the
warp diminished by another improvement, which
consists in lowering the warp-threads as well as rais-
ing them; whereas in the ordinary Jacquard loom
those threads which are not carried up by the lifting
bars, are allowed to remain in the horizontal posi-
tion.” 1 Messrs. Taylor and Son exhibited a power-
loom with four Jacquard cylinders working simul-
taneously. M. Moreau exhibited a Jacquard loom in
which a cylinder like that of a barrel-organ, provided
with pegs capable of being shifted to suit any re-
quired pattern, is substituted for the usual chain of
cards. _
The wear and tear to which the cards are subjected
in the ordinary Jacquard loom is such, that in the
weaving of carpets they often require to be made of
iron plate. In Martin’s new Jacquard loom, lately
described by Mr. E. Laforest at the Institution of
Civil Engineers, the object has been to substitute for
the heavy cards a sheet of prepared paper punched
with given apertures like the cards of the old ma-
chines, but instead of being a series of pieces 2%,; inches
wide, laced together, the punched paper formed a
continuous band only a}; of an inch wide, thus so di-
minishing the bulk that the weight of the new band,
as compared with that of the old cards, was in the
proportion of 1 to 11. The method by which this
desirable result had been attained was explained to
be chiefly an arrangement which permitted the 4100
spiral springs on the needles used in the old machine
to be dispensed with, when, as a conseqhence, the
force and wear and tear due to their resistance would
be done away with, and fine and light wires could be
made to do the work of strong and heavy ones. The
next point brought forward was, that, like the bulk
and weight, the cost of the cards under the new

(1) Jury Report. Class VI.
WEAVING.
961
system would be greatly reduced. It was shown that,
by an improved system of punching machinery, the
bands could be cut from a design, previously perfo-
rated, at the rate of 3,000 cards per hour, and any
duplicate could be produced with equal celerity; it
was also stated, that by these means, when a pattern
became fashionable any number of looms might be set
to work on it, in about as many days as it had pre-
viously required weeks, under the old system. The
price of the old cards was (is. 9d. to Ss. 6d. and up-
wards per 100 for new sets, and 58. (id. for recuts:
whereas the new paper bands would cost Is. per 100,
and 6d. per 100 for recuts. The comparison of cost
of 3,000 cards (an average band) would therefore
stand thus :—-
Cost. Weight.
Length
8,000 cards at .... .. 6s. 9d. per 100 106. 2s. 6d. 90 lbs. 600 ft.
3,000 new bands at 1s. 0d. per 100 ll. 10s. 0d. 851 lbs. 63ft. 9in.
In reference to durability, it was stated that a band
had been in constant work for two years, although
used on a heavy waistcoat piece.
See'rron IV.—-ON Mncnnurcnn on. Power.
Wnnvme.
It was long a mechanical problem to construct a
machine which should repeat with precision the some-
what complicated motions required in weaving. These,
as we have seen, consist in,—1st, alternately depress-
ing the treadles; 9d, throwing the shuttle between
the alternate threads from right to left, and from
left to right; and, 3d, driving home the weft by
means of the batten. Towards the end of the seven-
teenth century, M. de Gennes forwarded the drawing
of a loom for mechanical weaving to the Royal Society
of London. It does not, however, appear that this
machine was more successful than many other similar
contrivances which were attempted during the eigh-
teenth century. In 17 811‘, however, Dr. Cartwright
had his attention directed to the subject of Ark~
wright’s spinning machinery, the productiveness of
which was such, that on the expiration of Arkwright’s
_ patents it was remarked, that “weaving mills ”
would be required to work up the yarn. After some
time, Dr. Cartwright succeeded in constructing a
weaving machine, and by its means weaving a piece
of sailcloth. The machinery was rude, and, to use
the words of the inventor, “the warp was placed
perpendicularly, the reed fell with the force of at
least half a hundredweight, and the springs which
threw the shuttle were strong enough to have
thrown a Congreve rocket. In short, it required
the strength of two powerful men to work the
machine at a- slow rate, and only for a short time.
Conceiving, in my great simplicity, that I had
accomplished, all that was required, I then secured
what I thought a most valuable property by a patent,
April 4th, 1785.. This being done, I then conde-
seended to see how other people wove; and you will
guess my astonishment, when I compared their easy .
modes of operation with mine. Availing myself, then,
of what I saw, I made a loom in its general princi-
voL. II. '

pics nearly as they are now made; but it was not till
the year 1787 that I completed my invention, when
I took out my last weaving patent, August 1 of that
year.” Dr. Cartwright established a power weaving-
mill at Doncaster; but his loom was found to require,
from time to time, so many modifications, that after
expending between 30,000 and 40,0001. he was com—
pelled to abandon his undertaking.
In the year 1791, a mill was erected by other
parties at Manchester, adapted to 4-00 of his im—
proved power-looms, for which he was to receive a
certain royalty for the use of his patent rights,v The
operative weavers opposed the undertaking on the
ground that it would deprive them of work ;. they
even set fire to the mill- which contained the power-
looms, and threatened to oppose by force their intro-
duction elsewhere; but, as ignorance is not capable
of arresting the progress of improvement in a free
country, the power-loom outlived the malice of the
Manchester operative weavers. In 1798, it was ap-
plied at Glasgow to the weaving of cotton fabrics,
since which time it has undergone various improve-
ments, and may now take its place with the beautiful
automatic machinery which has been described under
Co'rroN. The country was not insensible of the
merits of Cartwright’s invention, and of the losses
which he had sustained in bringing it to bear, for in
the year 1808 the House of Commons voted him the ~
sum of 10,0001.
Fig.2321, represents the essential parts of the
power-loom independently of its framing, and the


Fig. 2321.‘ wonruue ran'rs or rowan LO'OM.
parts for communicating motion. The warp W, wound
upon the warp~beam w B, passes over a roller It, and
is then carried through two healds H I-II',—-which form
the shed for the passage of the shuttle; this is
driven along the shuttle race by a kind of hammer it
worked by a lever 1 moving through a small are of a
circle. The finished cloth C is kept distended by the
temples t, the portion wound upon the cloth-beam
being shown at e, n. Fig. 2322, is an enlarged repre-




' Fig. 2322.
sentation of the apparatus for projecting the shuttle
through the shed.
3Q
962
WEAVING.
In the power-loom, there are five distinct actions
performed by steam-powerz—Ist. To raise and
depress the alternate threads of the warp. 2d. To
throw the shuttle. 3d. To drive up each thread of
weft with the batten. 41th. To unwind the warp
from the warp-beam. 5th. To wind the woven fabric
on the cloth-roller. There is also a 6th action fre-
quently introduced, viz. an arrangement for stopping
the loom in case a thread should break, or when the
shuttle traps, that is, sticks in its course through the
thread, or when the cop of yarn contained in the
shuttle is run out. The mode of producing this
automatic stoppage varies according to the general
arrangement of the loom; but the following brief
description of one variety will illustrate the principle.
When a weft—thread breaks, there is no delivery
from the shuttle; there is a consequent want of
filling to the cloth; and the reed, in beating up,
will not meet with that resistance which it did when
the filling of the weft-thread was perfect. In the
beating up of the lay, therefore, the reed frame
will be driven back a little less than usual; it
will act less upon a particular lever; the lever will
act less upon a rod ; the rod will fail to move a click
over a tooth of a ratchet-wheel; and the yarn-beam
will cease to give out warp.
The following arrangement is now more common:—-
attached to the back of the beam which carries the
shuttle is a three-pronged piece of iron, somewhat like
a large fork, over which the weft passes. A two—
pronged piece, hinged to the beam, falls on the thread
stretched across the fixed prongs, and is prevented by
the thread (if this be perfect) from falling lower so
as to set free a catch. The prongs of the hinged piece
always'tend to fall through the fixed prongs at each
blow of the beam, and do so fall through if the thread
is not stretched across the fixed prongs to prevent
the passage of the movable piece. If they do fall
through, a catch is released, which allows a tumbling
bob to fall, and this shifts the strap from the fast to
the loose pulley. The projecting arm of the hinged
piece serves to lift the prongs at each movement of
the beam, to allow the shuttle in its passage to lay the
weft across the prongs.
A self-acting contrivance of this kind for stopping
the bobbin in the doubling-frame on the breaking of
a thread is shown under SILK, Fig. 198d. Dickinson
85 Willan’s Power-loom embodies a modification of
the stop—motion, by which the common slip—rod and
frog are dispensed with, doing away with the concus-
sion arising from their coming in contact by stopping.
Power-looms are usually contained in one large
room or s/zecZ on the ground floor. When 1,000 or
1,500 of these looms are at work at the same time,
they produce a noise which overpowers other sounds.
The looms are attended by women and girls, who see
that the work goes on properly, supply the spindle of
the shuttle with fresh cops when required, and adjust
the temples from time to time. One woman and a
girl can attend to four looms; or one woman, unas-
sisted, can attend to two. There is also an overseer,
who has the care of 7 0 looms, whose duty it is

to correct defects in the machinery, and to remedy
any mishaps which are beyond the power of the
women. The length of calico woven at each loom is
variable; in some cases 600 yards of warp are formed
into 10 divisions; in other cases the divisions are from
25 to 70 yards each. When the piece of cloth is
woven, the female attendant conveys it to a “ taking-
in-room,” where it is examined. Credit is given to
her for the piece, and should any flaws occur in it,
they are noted down; a mark is then made on a tally,
which the woman produces, and at the end of the
week she is paid according to the number of pieces
taken in.
These details refer to Mr. Orrell’s mill at Stockport,
which the editor visited some years ago. In Messrs.
Ackroyd’s power-loom shed at Halifax, which he also
visited, there were 17 rows of power-looms, each
containing 48 looms. A large proportion of the looms
were mounted with the Jacquard apparatus, one set
of cards serving two looms.
SEcrIoN V.-—-CARPET Wnavnve.
In former times the floors of houses were covered
with hay, straw, or rushes. The first advance towards
a carpet was made by plaiting the rushes into matting.
In a country like England where wool was abundant,
a coarse woollen cloth was spread on the floor of some
of the rooms of the gentry. This was at first of one
colour, and afterwards of various colours grouped into
a certain pattern. As it is probable that the smooth
turf suggested the use of a carpet, so the flowers
which enamel the one may have suggested the orna-
ments for the other. It is to be regretted that the
suggestion should have been forgotten in designing
patterns for carpets, for instead of the beautiful and
simple objects which adorn the turf, we often see
on carpets architectural scrolls, and heavy decora-
tions, portraits of animals, &c., on which it would be
impossible to walk, if the real instead of the simulated
objects were placed on the ground. Design in the
useful arts when regulated by common sense and
propriety, without which good taste cannot exist,
would not place on the floor decorations intended for
the walls, or for the vertical lines of a building. The
carpets of Turkey and Persia (which probably pre-
sent to us the most ancient mode of carpet weaving)
do not err in this respect; they are soft in texture,
pleasant alike to the feet and to the eyes, presenting
not a pattern, but a harmonious shading or grouping
of colour, not of light and bright colours, (such as
would be soiled, and would require the absurd
anomaly of another carpet of inferior material placed
upon it to preserve it,) but of dark, unobtrusive
colours, which give repose to the eye, and do not
divert the attention from the lighter and more bril-
liant decorations of the walls and ceilings, which, not
being trampled on, are not liable to soil, and indeed
require to be light and bright, in order to reflect the
light of the room, and thus contribute to its cheer-
fulness.
The manufacture of carpets is said to have origi-
WEAVING.
963
nut-ed in Turkey and Persia; it is also of ancient
date in India and Tunis, which countries, during a
long period, supplied Europe with this article of
luxury. In the middle ages, carpets were first used
before the high altar and certain parts of the chapter
in abbeys. Bedside carpets are noticed as early as
1301; and in drawings of the 15th century, the
royal throne is represented as being surrounded by a
carpet of a simple flower pattern. Turkey carpets
before the communion table are noticed in the reign
of Edward VI , Elizabeth, and James.
The manufacture of carpets is said to have been
introduced into Europe by the French, in the reign of
Henry IV. The largest manufactory was that of
Chaillot, or the royal manufactory of La Savoaiere,
or the “ Soap House,” situated about a league from
Paris. The carpets were of wool, and were worked
in the manner of velvet, as in the modern Wilton
carpet. This method of carpet weaving was intro-
duced into London about the year 1750, by two
workmen, who had left Chaillot in consequence of
some dispute, and came to England for employment.
They were encouraged by Mr. Moore, to whose
assiduity the manufacture in this country is princi-
pally owing; but after a time these men left Mr.
Moore, and in company with one Parisot, under the
patronage and with the pecuniary assistance of the
Duke of Cumberland, established a manufactory at
Paddington, and afterwards at Fulham. Mr. Moore,
however, was a formidable rival to the scheme; his
manufactory flourished, and in 1757 he obtained a
premium from the Society of Arts for the production
of the best imitation of a Turkey carpet. The
Turkey carpet, however, consumes a large quantity of
materials, and is slow in being produced. Hence it
is an expensive article. The introduction into this
country of other and cheaper modes of weaving car-
pets, led to a general taste for this luxury, so that
a room not covered with a carpet was regarded as
unfurnished. On the continent of Europe this taste
has never become common; and the inlaid fioor
polished with wax is still continued in the houses of
the wealthy, while in poorer houses the plain deal
boards remain without a covering.
There are chiefly six varieties of carpet in this
country, viz. the Aamiizster, the Venetian, the Kid-
dermz'aster, the Scotch, the Brussels, and the Wilton.
These names, however, do not point out either the
present or the original seat of manufacture, for the
Axminster carpet is similar to the Turkey, but even
more expensive: the one being made of worsted, the
other of woollen yarn. The manufacture of Turkey
carpets at Axminster in Devonshire, and at Winfield
in Yorkshire, ceased about 25 years ago. Venetian
carpets, made in narrow widths for staircases and
passages, did not originate in Venice, and are not
even made there. The Kidderminster carpet presents
an example of doable-weaning or two-ply, and is pro-
duced by incorporating two sets of warp, and two of
weft yarns; such are called in America iii-grain car—
pets. They are manufactured not only in Kidder-
minster, but in Yorkshire, and in Scotland. Scotch

carpeting is the same as Kiddcrminsteig'but it includes
a three-ply, or triple iii-grain carpet; also manufactured
in Yorkshire and Kidderminster. Brussels and Wilton
carpets are also manufactured at Kidderminster.
For the manufacture of woollen or worsted yarns
used in carpet-weaving, we must refer to the article
WooL. Some carpet weavers receive their yarns “in
the grease,”—-—that is, spun, but not dyed, and they dye
them previously to weaving. Some factories, how—
ever, perform all the processes required for the pre-
paration of their carpet yarns. In Eastern countries the
manufacture is carried on in pastoral districts, where
it serves to fill up the leisure of cultivators and their
families. The loom consists of two upright pieces
of wood fixed at some distance, supporting a roller at
the top, on which the warp or chain is wound, and
a second roller about 2 feet from the floor, upon
which the finished carpet is wound. The work is
done entirely by hand: coloured worsted is tied in
short lengths, each tie passing across the face of
two warp threads round the back, and has the ends
brought up between them. When a row of ties has
been completed, a shed is formed in the warp, and the
shoot is passed across from right to left and returned,
binding the whole together, and is beaten down to a
horizontal level by hand-boaters. In the Great Exhi-
bition there was a carpet from Cashmere, made
entirely of silk, and containing at least 10,000 ties in
every square feet. It was remarkable for the beauty
of its texture, and the softness and harmony of its
colouring. _
The ray—loom or Tar/my carpeHoom of Europe is
similarly constructed. It consists of two beams, one
above another, as in the above arrangement; the
warp or chain, of strong linen yarn, is mounted on
the upper beam, and brought down through headles
to the lower beam. The weaver is seated as at the
common loom, and having thrown a weft thread once
or twice across, he fastens to every thread of the
warp, by a peculiar twist, a small bunch of coloured
yarn, varying the colour according to a pattern before
him. One row being completed, he passes a linen weft
through the web, and drives it well up, so that the
small bunches or tufts may be held securely. An-
other row of tufts is then twisted in, according to
the pattern. In this way narrow breadths of carpet
are produced, which being placed side by side and
joined together, form one large carpet ; the surface is
then sheared, so as to produce one level. Rays are
formed by a similar contrivance. A number of co-
loured worsted yarns are hung over a bar to the right
of the weaver, who, taking the end of one yarn, at-
taches it to the chain, cuts it off to the proper length,
then twists in another, which he severs in the same
manner, and in this way forms a row of tufts across
the warp; be next passes a shoot or two of weft, and
then drives up the weft with considerable force.
Young girls are employed in rug-making; their nimble
fingers tie in the coloured worsteds with great rapi-
dity, and, from constant practice, they know which
particular colour to use at any particular spot, with‘
out referring to the pattern sheet.
3 Q 2
964 ~
WEAVING.
Venetian carpets are also produced at a common
loom. The pattern is formed entirely by the warp, the
weft being concealed: the warp consists of a heavy
body of worsted, arranged so as to form stripes, which
shade off imperceptibly from dark to light. By using
shoots of different kinds plaids and checks may be
formed, and by a proper arrangement of the headles
a twilled or dotted pattern may be produced. Date/z
carpeting is similar to plain Venetian, but coarser,
cow-hair being sometimes introduced.
The Kidderminster, or Scotch carpet, has a worsted
chain and a woollen shoot, and consists of two distinct
webs incorporated into each other, so as to produce
the pattern. Each cloth is perfect in itself, so that if
one cloth were carefully cut away, the other would
appear like a coarse baize. Both cloths are woven
simultaneously, one or other cloth being brought up
to the surface as required to produce the pattern in
any particular part. There is always a tendency to
the formation of stripes in this species of carpet,
since the pattern is produced by one set of coloured
stripes crossing another, and much skill is required
in the arrangement of these stripes. Full colours are
obtained by crossing the warp with similarly coloured
weft, and any particular colour can be concealed by
sending the threads to the other web. In general
the warp is not much varied, variety of colour being
produced by the weft. For example, the weaver has
often a warp of two colours only, such as white and
maroon: across the white he may throw white, drab,
fawn, light-green, and yellow, to form a fancy or
shaded ground. With the maroon warp he may use
two or three different shades of weft consisting of
full greens, scarlets, crimsons, blues, and olives. The
warp shows very little upon the face of the carpet.
A two-ply Kidderminster, from the nature of its con-
struction, has a right and a wrong side, the colours
being reversed. If, for example, the colours be green
and red, the green portions on the one side will be
red on the other, and vice cersai A Jacquard appa-
ratus is attached to the loom for regulating the pat-
tern, and the weaver has a variety of shuttles, con-
taining wefts of different colours. The pattern-designer
in this style must arrange his figures, and dispose of
his colours, so as to conform to the restrictions under
which the weaver is placed. The three-ply carpet
allows of greater variety and brilliancy of colour than
the double carpet, while its great thickness and com-
parative cheapness are great recommendations. It is
largely manufactured at Kilmarnock.
A variety of carpet called British or damask Vene-
time, is a kind of mixture of Venetian and Kidder-
minster. It resembles Kidderminster in the weaving,
but in Venetian the warp only is seen, while in
Kidderminster the shoot is chiefly at the surface.
This variety is also called Freeze/Z, or tapestry ear-
petz'ag.
In Brussels carpet there is a linen web, enclosed in
worsted yarns of difierent colours, raised into loops
to form the pattern. The structure of this carpet is
represented in Fig. 2323, in which the small black
dots represent the ends of the shoot, and the double

waving lines two separate sets of linen warp or
chain: between the black dots, or between the
upper and under shoot, is the worsted yarn, usually



Fig. 2323.
consisting of 5 ends of different colours; each end
may consist of 1, 2, or 3 threads, according to the
quality of the carpet. Supposing there are 2 threads
to each end, which is the common number, there will
be 10 threads bound into the carpet every time the
warp is shed. The pattern is formed by bringing to
the surface at any particular spot, such of the five
coloured yarns as are required, and they are formed
into loops by being turned over wires which are re—
presented in the figure by the large black dots. As
the coloured threads are taken up very unequally,
they are not wound upon one beam, but are placed
separately upon separate bobbins, arranged in frames
at the back of the loom, with a small leaden weight
or bullet attached to each
bobbin, as in Figs. 2324:,
2325, which show a bobbin
nearly empty, and one full
of yarn, to keep the worsted
slightly stretched. The
bobbins are mounted in
pairs, as shown in Fig.
2326, with a wire or sym'z‘,



Fig. 2324». Fig. 2325. Fig. 2326.
also called a benelzzoz're, passing through them, and
resting in grooves upon the frame. Such is the ar—
rangement at Kidderminster. At Wilton, the arrange-
ment is somewhat different, and will be explained by
referring to Figs. 2327, 2328, 2329.

_ f.:-;.n:..r.=':';'. , :iillw ‘liq-g‘ , I n
i e . ;jraLJl'IJzi'fl-y'é:
;nip 1'




Fig. 2329.
The loom itself is represented in Fig. 2330. In
such a loom there are as many frames as there are
colours; the number of bobbins in each frame is
WEAVTNG.
965
would be able to get rid of all the apparatus for
producing the pattern, the web being worked with
regulated by the width of the carpet. The usual width
is three-quarters of a yard, in which case there are
260 bobbins to each frame. But if the carpet be a
“ " yard wide, the number of bobbins is 34:41. From each
bobbin, the ends are carried through small brass eyes,
called males, or mails, attached to fine cords, one eye
and one cord for each end. Each cord is passed over
if .s'ltr . .
agar tr"
r"




E‘.
_
“7:,
innzglénwrnmsm


Fzg. 2330.
BRUSSELS CARPET LOOM.
a pulley fixed above the loom, and is brought down
again by the side of the loom, and is fastened to a
stick. For a three-quarter carpet, there are 1,300
of these mails, cords, and pulleys to each loom; the
pulleys are arranged in a frame or box at some dis-
tance above the mails. It is evident, that by pulling
the cords as they hang at the side the mails or brass
eyes will be raised, and with them the worsted ends
which pass through them; but if all the ends are
raised simultaneously, no pattern will be formed; an
arrangement must therefore be made beforehand, to
pull such of the 1,300 cords as will raise the colours
required in each particular spot, for which purpose,
in the absence of the Jacquard apparatus which is
now commonly used, the, draw-loom already referred
to in a previous section is employed. We have seen
it in use within a few years at Kidderminster, ar-
ranged in the following manner. Those cords which
will raise to the surface certain yarns required for the
pattern are bound together into a last. One lash is
necessary for every set or row of colours that has to
be drawn to the surface, and the lashes are taken in
regular succession until the pattern is complete. The
number of these lashes is often large; as many as
320 may be required to make out a pattern a yard
long: this being completed, the succession of the
lashes is repeated for the repetition of the pattern.
The lashes are pulled by an assistant boy or girl,
called the drawer. Supposing the loom to be at
work, the drawer takes the first lash, and gently
draws forward the 260 cords, whereby they are sepa—
rated from the others. He then pulls the lash with
considerable force, and thus raises such of the 1,300

ends as are required to be raised for the pattern; in—
serting with the other hand, under the raised ends, a
light wooden board, or sword, about 3 feet long, and
5 inches wide; it is set up on edge, so as to retain
the raised ends about 5 inches above the surface.
The drawer then lets go the lash, and the weaver in-
serts into the bosom, or opening formed by the sword,
a round wire through the whole width; the drawer
takes away the sword, and the weaver depresses one
of the treadles, whereby one of the linen warps is
raised above the surface; while the other warp,
together with all the remaining worsted ends, is de-
pressed. The shuttle with a linen shoot is then
thrown in, the weaver depresses the other treadle,
whereby the worsted and the warp before depressed
are now raised, and then throws in a second or under
shoot, forcing the materials.closely together with a
heavy batten. This completes the weaving of one
wire 5 a second lash is then drawn, and the work pro-
ceeds as before. When a number of wires have been
thus woven in, they are drawn out one at a time with
a hook inserted into a bow at the end of each wire;
but the last five or six wires must be left in, or the
worsted loops would be drawn down flat, and show
the linen web. Sixty wires form what is called
a set.
The Wilton carpet, called Mogaeta‘e by the French,
differs from the Brussels in the form of the wire, and
in the method of removing it from the loops. The
wire used for the Wilton carpet has a groove in the
upper surface, as in Figs.
2331, 2332, and the edge of £3
a sharp knife being drawn Fig. 2331- Fio. 2332-
along this groove, the wire is thus liberated. The
worsted loops thus out form a pile or velvet, the
structure of which is represented in Fig. 23041. By
increasing the size of the wire, the Wilton carpet
can be increased in thickness or quality. The quality
of Brussels and Wilton is measured by the number
of wires included in the inch ; the usual number is
9 for Brussels, and 10 for Wilton, but whatever
number is adopted, great uniformity must be ob—
served, or the pattern would not match when the
breadths were joined together at the sides. As a
guide to the weaver, a bell is made to ring when
64:, 80, or 90 lashes have been woven; he then as-
certains by a measure whether the required number
of lashes measures a quarter of a yard; if too
short, he repeats the last lash, or omits it if too
long. The length of a piece of Wilton carpet is
36 yards. After the weaving, the nap or pile is
sheared after the manner of broadcloth, [see Woon]
the action of the knife being assisted by circular
brushes. '
It will be seen from the foregoing details, that in
the production of the Brussels carpet, only one of the
5 sets of coloured yarns appears on the surface at
any particular spot, the other four being concealed
in the web. Mr. Whytock has effected a great eco-
nomy in this respect. It occurred to him that if
for the 5 coloured yarns he could substitute one yarn
dyed of the requisite colour at different places, he
966
WEAVING.
only one body like a simple velvet. His arrangement
for dyeing the warp-threads is as follows :——The
yarn is arranged in regular coils on the surface of a
large hollow drum, Fig. 2333, on a horizontal axis;
the surface of the drum is covered with blanket,
is‘ a
/,
l,‘- at‘,
- a . r \
‘ “. \\ ,
‘i
and on this is oil-cloth, to keep the blanket clean.
The dye is applied to the yarn by means of rollers;
each roller is about 9 inches in diameter, and t— inch
wide, and works in its own colour-trough, supported
by a low carriage. To apply the colour to the yarn,
the carriage is moved across the cylinder, when the
roller is made to press by means of springs against
the coils of the yarn, thus imparting to them a
coloured streak without any pattern, a portion of
each coil being stained to an extent equal to the
printing surface of the edge of the roller. When the
yarn is unwound, the coloured marks thus produced
will be at equal distances along the length of the yarn.
One impression being made, the cylinder is turned
round through a space equal to the breadth of the
impression left by the roller; and then, if the pattern
require a change of colour, another roller charged
with another colour is applied across the yarns so as
to make a second streak by the side of the first. By
a. repetition of this process, the cylinder of yarn is
completely covered with streaks, the colours being in
the order required by the pattern in the woven fabric.
The yarns are next removed from the cylinder, toge-
ther with the oil-cloth covering, upon which they are
kept extended until the colours are dry. The yarns
are then made up into hanks, and the colours fixed
by steaming. [See CALICO PRINTING, Fig. 416.]
They are next washed in water, to remove the gum
or paste with which the colours are mixed up, and
after being dried they are wound upon bobbins for
warping. In the mean time another set of yarns is
Wound upon the cylinder, and dyed by a similar pro-
cess, and in this way the whole of the warp—yarns are
prepared. The party-coloured threads are next ar-
ranged side by side to form the warp. As each yarn
forms several coils round the cylinder, the order in
which the colours succeed each other on each yarn
will be repeated at intervals along a length of each
yarn equal to the circumference of the cylinder. The
succession of colours is determined by a design paper
containing the pattern, ruled with squares, the lines
being numbered along the top and down the length,
and containing the entire figure of the pattern, so
that, whatever number of squares the design paper
occupies, the circumference of the cylinder must be
divided into a like number of equal parts, or a mul~
tiple thereof, such as the double and the treble. In


. In
=is
i


Figfzsss.
applying the colour to the yarns, a narrow black line
is impressed across them as a common starting-place
for all the yarns, and this black mark is to be re-
peated at the points where the repetition of the pat-
tern begins. All the yarns being properly adjusted,
the black marks will range in a straight line across the
breadths of the warp, and the pattern will be cor-
rectly made out by the party-colours of the yarn. To
keep the colours in their places, a clamp, Fig. 2331i, is
applied across the warp, which is shifted across as


Fig. 2334.
the weaving proceeds. The weaving is conducted
after the manner of plain weaving, without the assist-
ance of the complicated apparatus required in figure-
weaving. When the weaver has woven one length
of the pattern, he moves the clamp to the next black
line. If the black marks which form it do not range
together, some of the warp threads are gently pulled
and adjusted, and the clamp is screwed fast as before.
If the warp be wound upon a beam before it is placed
upon a loom, the clamp is not required in weaving,
but only in beaming; but when the warp proceeds at
once from the bobbin to the loom, the clamp is used.
Some years ago, a plan was introduced for the
manufacture of carpets, rugs, &c , by cementing a
nap or pile to plain cloth without any kind of weav-
ing being used. For this purpose a number of threads
or yarns of twisted wool, cotton, silk or mixtures of
these materials, are warped upon' a beam, Fig. 2335,
supported at one end of a. frame, and weighted with
friction cords to keep the yarns stretched. The ends







Yi'mrvw
M '1 l’ l’ .,"'."l
u‘ll'lliliilllili‘ilg“ 413-‘ '7' '
stf'xi‘ - ‘ ‘Fr
,ni‘liltilvlll" ..
,ifhlhllllliflglliillu "l'
O








Fig. 2335.
of the yarns are drawn forward and attached securely
to the front rail of a frame. The workman has a
number of strips of metal of the same size, somewhat
longer than the width of the intended fabric, but their
width is equal in height to its pile or nap. The man
first places a single strip beneath the warp, and, draw-
ing it up to the end, and parallel with the front rail,
he places it upon its edge, and inserts its two ends into
grooves in the sides of the frame, whereby the strip
is prevented from rising up ; he next places the second
strip edgeways on the upper side of the warp, and
depresses the threads evenly between the two strips,
inserting the ends of the second strip into side grooves,
as before: the third strip is put under the warp, the
fourth strip upon the warp, and thus the work pro-
ceeds until the frame is full, when the warp will be
so arranged within the strips as to pass first under
and then over each succeeding strip, as in 2336.
The surface being brushed or combed, to bring the
fibres into contact, a quantity of solution of India
WEAVING.
967
rubber, or other cement, is spread over it, and a piece
of canvas or coarse cloth is laid on to form the back,
a heated roller being
applied to promote the
lllllOn.
ment is dry, the frame
is turned over, and the
metal, strips are cut out, as in the Wilton carpet. A
soft pile is thus produced without any pattern, unless
yarns of different colours be introduced into the warp
so asto form stripes ; or the yarns may be first printed,
as in Whytock’s process. For a figured pattern, the
l ollowing is the arrangement :--Two frames, containing
wire gauze, or perforated zinc, (4,000 perforations to
the inch being sometimes used,) are placed exactly over
each other vertically, the distance apart being only
regulated by the height of the room. The pattern or
picture which is to be copied is arranged in the same
way as the patterns used for worsted-work, the colours
being contained in small squares. For some patterns,
however, a tracing may be made on the top side of
the upper frame. A workman then passes threads
of dyed wool through the corresponding holes in the
top and bottom frame; the upper ends of the threads
guiding him in the choice of shade and colour, the
space between the frames being filled with a compact
and apparentlyconfused mass of worsted thread. By
another contrivance, a number of frames are fixed
upright, at equal distances apart, in a stand, as in
Fig. 2337. A piece of canvas, such as is used for
worsted-work, varying in fineness with that of the




Fig. 2337.
materials used, is stretched Within each frame. The
workman has a pattern-paper before him, or the pat-
tern may be sketched on the canvas itself. A needle,
containing the worsted or other yarn, is then drawn
through a hole or mesh in the canvas at one end, and
then through corresponding holes in the canvas of the
other frames ; it is usual to begin at the lower corner
hole, and to work successively through each hole of
the lower holes of the canvas. The next row of holes
is then worked, and so on; and the threads or yarns
between the frames must be drawn equally tight, so
as to lie smooth and even.
filled, the spaces between the frames will be occupied
by long quadrangular masses of yarn. This collection
of yarn is next introduced into a case open at both
ends, Fig. 2338, but composed of parts held together
by screws, so that the yarn may be introduced by
removing the top side. A solid ram or piston fits
' into one end of the case, for the purpose of forcing out
portions of yarn as they are required. A solution of
When the ce- ~
When all the holes are >

India rubber, or other cement, is applied to the fibres
at one end of the case, and when dry, a quantity of


Fig. 2338.
yarn, equal to the length of the pile or nap, is forced
out of the case by means of the piston. Such a length
is then cut off with a sharp thin knife, as in Fig. 23-39;
the ends of the yarn left in the case are again coated
} i
Fig. 2:39.




with cement, another portion is protruded and cut
off, and in this way the whole mass of yarn may be
cut up into slices, which may afterwards be cemented
to rough canvas, or to other fabrics. It is evident
that each portion or slice is a repetition of the same
pattern. The productiveness of this arrangement is
also extraordinary; with the two outer frames five
feet apart, as many as 480 slices or copies of the
pattern have been obtained. The pile can be cut to
any length, from the eighth of an inch upwards.
When a laid nap is required, the ends of the case
from which the section is made are on a bevel, the end
of the piston is also on a bevel; so that each slice will
be protruded and cut in an angular direction, and
when cemented, will produce a laid nap. Another
method of forming a napped surface, is simply to wind
the thread or yarn spirally round thin strips of metal,
as in Fig.23et0; and a number of such covered strips
being packed side by side in a frame, and the upper
surface covered with cement, and
some coarse fabric for a back, mm
when the whole is dry, the strips
can be cut out as already ex- Fig-234°‘
plained. The nap for hats and bonnets prepared in
this way may be at once cemented to them.
There are various methods of manufacturing mat-
ting from straw, rushes, and other grassy stems of
plants. Russia matting or best is, however, made
from the inner bark of the lime-tree, while the
fibrous covering of the cocoa-nut furnishes a mate-
rial of great strength and utility for matting. The
materials for door-mats are very numerous; they
may be rope, hair, basket-work, straw, sheep-skin
with the wool on, goat-skin, tow, &c. Untwisted
rope-yarn is also employed, woven into coarse canvas,
and then cut so as to present a brush-like surface.
The term tapestry is usually appliedto fabrics com~
posed of wool or silk, in some cases enriched with
gold and silver, woven or embroidered with figures,
landscapes, or ornamental devices. The French word
t’apis, from which it is derived, although commonly
applied to carpets, is also used to designate other
figured cloths employed for covering the walls of
968
WEAVING.
apartments, (which is the proper application of tapes-
try,) and also as the covering of tables, from which
latter use, probably, arose the expression “ on the
tapis,” applied to subjects under discussion. The
early method of working tapestry was with a needle,
the wool being worked into a coarse kind of canvas;
the finer kinds were embroidered on a silken fabric. As
early as the 14th and 15th centuries the art of weav-
ing by the loom, in the karate lime or high-warp style,
was practised in the tapestries of Flanders, and per-
haps in those of England. In the [mute lisse, the
frame containing the warp-threads is vertical, and the
weaver works standing; in the basse lisse, on the
contrary, the warp-frame is horizontal, and the weaver
sits to his work. In the basse lisse the painting to
be copied is placed beneath the threads of thewarp;
the weaver carefully separates the threads with his
fingers so as to be able to see a portion of his pattern,
and then with a shuttle called a jlziz‘e, containing silk
or wool of the required colour in the other hand, he
passes it into the shed formed by depressing the
treadles, worked in the usual way. The weft, thus
introduced, is driven up to the finished portion of the
work, with the teeth of a box-wood or ivory comb.
In this kind of weaving the face of the work is down-
wards, so that the weaver cannot examine it until it
is removed from the loom, a circumstance which pro-
bably led to the disuse of the basse lisse. In the
haute lisse the loom consists of two upright side—
pieces, with large rollers placed horizontally between
them, the warp, usually of twisted wool, being wound
on the upper roller, and the finished web on the
lower one. The cartoon or pattern sheet is placed
vertically behind the back or wrong side of the warp,
and the principal outlines of the pattern are sketched
upon the front of the warp, the threads of which are
not so close as to prevent the artist from seeing the
design between them. The cartoon is now removed
to such a distance from the warp, as to allow the
weaver to stand in the space between, and he works
with his back to the pattern sheet, so that he must
turn round when he wishes to inspect it. The side
pieces of the frame contain the means for forming a
shed in the warp threads for the passage of the weft;
a reed or comb, or a large needle, called an az'guz'lle
a presser, being used to force home the weft. As in
the case of the basse lisse the artist works at the back
of the fabric, but by walking to the other side of the
frames he is able to inspect the work and correct
defects. The progress of the work is almost as slow
as in working with a needle. The breadths of tapestry
are united into one picture by fine-drawing, and so
skilfully that no seam is to be perceived. At the
present day, however, the frames are made so wide
that the largest pieces are woven without joining.
Snorron VI.—- On Laos AND BOBBIN NET.
Lace is a kind of net-work of threads of gold, silver,
flax, or cotton, forming a transparent texture. The
word is said to be derived from the Latin lacz'mla, the
guard hem or fringe of a garment. The origin of this
delicate fabric is not known. It seems to have been

worn by the Grecian and Roman ladies. It was in
use at an early period in Venice, and the north of
Italy, and is said to have been introduced into France
by Mary de Medecis. It was known in England in
M83, in which year it is included in a list of articles
not allowed to be imported; but as pins which are
required in lacemaking were not used in England till
1543, the lace must have been of a coarse kind. The
lace manufacture is said to have been introduced into
this country by some refugees from Flanders, who
settled at Granfield in Bedfordshire. In 1640, the
lace trade was flourishing in Buckinghamshire, and in
1660 a royal ordinance was passed, establishing a
mark on the thread lace exported from this country.
Pillow or bobbin-lace, the original manufacture,
was usually made of thread or silk woven into
the net with hexagonal, octagonal, &c. meshes. It
was afterwards ornamented with a thicker thread
called gimp, so interwoven with the meshes as to
form flowers and curved designs. This kind of lace
was made on a hard, stufied, pillow or cushion,
covered with parchment, on which the pattern was
drawn. Each thread was wound upon a bobbin, a
small round piece of wood, with a deep groove in the
upper part for retaining the thread. To form the
meshes, pins were stuck into the cushion and the
threads woven or twisted round them. The pattern
on the parchment indicated the spots for the insertion
of the pins, and also showed the place for the gimp,
which was interwoven with the fine threads of the
fabric. The work was begun at the upper part of the
cushion by tying the threads together in pairs, each
pair being attached to a pin. Bobbins were allowed
to hang down by their threads on different sides of
the cushion, but at the commencement of the work
they were all arranged on one side, and were brought to
the front side, two pairs at a time, and twisted toge-
ther. The woman, holding one pair of bobbins in
each hand, twisted them over each other 3 times, so
that the threads of each pair became twisted together
or round each other, so as to form the sides of the
mesh. The adjacent bobbins of each pair were next
interchanged, in order to cross these threads over one
another to form the bottom of the next. Supposing
the four bobbins to be marked a, b, a, (Z,- a is twisted
round 6, and a round d ; these in order to cross I; and
a, are interchanged, so that a and c, and 6 and a? come
together; the next time the twisting is performed
these pairs of thread will be combined together. As
the meshes or half meshes are made, they are secured
by pins to prevent the threads from returning. The
four bobbins a, b, 0, (1, being done with for the pre—
sent, are put on one side of the cushion; the two
next pairs are then brought forward, twisted, and
crossed in the same way. These operations are re-
peated until a row of meshes is formed, sufficient for
the breadth of the intended piece of lace; the bobbins
are then worked over again to form another row. As
many as from 48 to 60 bobbins are required for every
inch of breadth, and only one mesh is made at a time.
A piece of lace one inch wide, with 50 threads per
inch, will have 25 meshes in the breadth, or 625
W EAVIN G.
969
meshes in each square inch of ‘length, or 22,000
meshes in the yard, while the cost of such a piece is
seldom more than 1s. 8d.
The most celebrated laces have been enumerated
as followsz—l. Brussels, the most valuable, and of
which there are two kinds; Brussels ground, having
a hexagon mesh, formed by plaiting and twisting four
threads of flax to a perpendicular line of mesh; and
Brussels uu're yrouud, made of silk, of which the
meshes are partly straight, and partly arched. In
both cases the pattern is worked separately, and set
on by the needle. 2. Mee/ilz'u; a hexagon mesh,
formed of three flax threads twisted or platted to a
perpendicular line or pillar. The pattern is worked
in the net. 3. Valeuez'euues, an irregular hexagon,
formed of two threads, partly twisted and platted at
the top of the mesh. The pattern is worked in the
net. 4:. Lisle, a diamond mesh, formed of two threads,
platted to a pillar. 5. Aleueou, called bloud; hex_
agon of two threads, twisted, similar to Buckingham
lace, and is considered the most inferior of any made
on the cushion. 6. Aleupou Poz'ul; formed of two
threads to a pillar, with octagon and square meshes
alternately.
The lace represented in the portraits painted by
Vandyke in the time of Charles 1., and afterwards
by Sir Peter Lely, and Sir Godfrey Kneller, in the
succeeding reigns, is Brussels l’oz'ul, in which the
net-work is made by bone-bobbins on the pillow, and
the pattern is worked with the needle. It is stated
that the first lace ever made in this country was of
this kind. “ About a century since, the grounds in
use were the old Moe/elm, and what the trade termed
the wire ground, which was very similar, if not iden-
tical, with the modem Jlfeelilz'u, the principal article in
the present French manufacture. The laces made in
these grounds were singularly rich and durable; the
designs of the old Mechlin resembled the figures com-
monly introduced in ornamental carving. Between
seventy and eighty years ago, a great deterioration was
occasioned by the introduction of the Trolly/ ground,
which was exceedingly coarse and vulgar, the figures
angular, and altogether in the worst taste. An im-
provement, however, took place about the year 1770,
when the ground which is probably the most ancient
known, was reintroduced; this was no other than
the one still in partial use, and denominated the old
Franc/i ground. About 1777, or 1778, quite a new
ground was attempted by the inhabitants of Bucking-
ham and its neighbourhood, which quickly superseded
all the others; this was the palm,‘ ground, which had
(as is supposed) been imported from the Netherlands.
From ‘the first appearance of this ground may be
dated the origin of the modern pillow lace trade; but
it was not until the beginning of the present century
that the most striking improvements were made; for,
during the last quarter of the eighteenth century, the
article, though certainly much more light and elegant
from the construction of the ground, was poor and
spiritless in the design. Soon after the year 1800,
a freer and bolder style was adopted, and from that
time to 1812, the improvement and consequent sue-

cess were astonishing. At Honiton, in Devon, the
manufacture had arrived at that perfection, was so
tasteful in the design, and so delicate and beautiful in
the workmanship, as not to be excelled even by the
best specimens of Brussels lace. During the late
‘war, veils of this lace were sold in London at from
20 to 100 guineas; they are now sold from 8 to
15 guineas. ~ The effects of the competition of machi-
nery, however, were about this time felt; and in
1815, the broad laces began to be superseded by
the new manufacture. The pillow lace trade has
since been gradually dwindling into insignificance.” 1
I'Ioniton lace is made by placing a perforated pat-—
tern on a pillow, and then so twisting and inter-
weaving the thread by means of pins, bobbins, and
spindles, as to produce the required pattern. Simple
sprigs and borders were formerly the only things pro-
duced, but at the present time the most beautiful
and delicate fabrics are produced complete by sewing
the hand-made patterns upon machine-made net.
Pillow or thread-lace is also made upon a cushion,
but it is distinguished from Honiton lace ly having
both the pattern and the mesh made by hand. British
point, tambour, and Limerick laces are often success-
ful imitations of Honiton and Brussels lace, and are
produced in shawls, scarfs, court-trains, flouncings,
&c. British point is made chiefly in the neighbour-
hood of London. Tambour is made at Islington, at
Ooggeshall in Essex, and at Nottingham. Limerick
lace is peculiar to Ireland, and is a valuable source of
industry in that country.
Lace is said to have been made by machinery so
early as the year 1768, by a stocking-weaver of Not-
tingham, named Hammond. Being out of employ,
the idea occurred to him, while looking at the pillow
lace on his wife’s cap, that such an article might be
made by means of the stocking-frame. He appears
to have succeeded in producing a machine which was
called a pin muc/u'ue for making single press poz'ul net,
in imitation of Brussels ground. This machine is no
longer used in England, but is in use in France in the
manufacture of not called tulle. Hammond’s success
led other workmen to attempt lace-making by the-
stocking-frame, and in their leisure hours they amused
themselves by trying to form new meshes on the
hand, in the hope of producing a complete hexagon,‘
a thing not as yet accomplished. The warpfi'ume for
making zourp lane was introduced in 1782, and from
1799 dates the first attempt to make bobbz'u not by
machinery. By this means the stocking-weavers pro-
duced an inferior kind of lace with such facility that
they could greatly under-sell the pillow-lace weavers,
whereby the demand for lace was increased, and
Nottingham soon became the centre of a new and
thriving trade.
Concerning this period in the history of the lace-
trade, it is remarked, in the Jury Report, Class XIX. :
——“ It has been matter of astonishment to see how
quickly one inventor has succeeded another, and by
simplifying or modifying his machines, rendered use-I

(1) M‘Culloch’s Commercial Dictionary.
Mr. Robert Slater.
Article L son, by
970
WEAVING.
less those of his predecessor. It may be stated, that
in none of the textile fabrics have there been so many
combinations of machinery used to effect the purpose
as in the making of lace, commencing with the stock-
ing-frame, to which was added a Tickler machine;
then the point-net machine, warp machine, Mechlin
plait machine, and many others. All of these (except
the warp machine) disappeared for the purpose of
making lace, when the bobbin-net machine was intro-
duced, and its capabilities for making both plain and
ornamental lace became developed. The bobbin-net
machine is so called, from the thread that makes the
lace being partly supplied from bobbins, and partly
from a warp.” /
No successful attempt to produce bobbin-net by
machinery occurs previous to the year 1809, when
Mr. Heathcoat patented a frame which is said to have
been suggested by a workman employed in making
fishing-net machinery; the idea occurred to him of
making lace by means of warp and weft threads, by
arranging the warp in parallel lines, and disposing
the diagonal weft-threads upon small detached bob-
bins, arranged so as to pass round and twist with the
intended warp-threads. The machine was successful,
and so far affected the pillow-lace makers, that they
formed themselves into a party, under the name of
“ Luddites,” for the purpose of putting down by
force the new invention. Mr. Heathcoat removed to
Devonshire, and was successful in the production of
machine-made bobbin-net. In 1823 his patent ex~
pired, and the manufacture revived at Nottingham,
where the lace-frame soon rivalled and superseded in
plain nets the productions of France and the Nether-
lands. The machine became the subject of frequent
improvement, and in the year 1816 was worked by
steam power. Lace became a general article of con-
sumption; that which had been sold at 5 guineas
a yard, fell to 1s. 6d. ; quillings sold in 1810 at 4s. 6d.
a yard, _were vended of better quality at lad. Instead
of smuggling French lace into England, English lace
was smuggled into France, until the continental
makers were allowed to protect themselves by using
lace—making machines.
A piece of lace (such as that represented in
Fig. 2341) will be found, on examination, to consist
of a series of nearly parallel warp-threads proceeding
in one direction, while the weft twists once round
each warp-thread until it reaches the outer one, when
it makes two turns, and then proceeds towards the
other border in a reverse direction; by means of this
double twist, and the return of the weft-threads, the
selvage is formed. The effect of the twisting and
interlacing of the threads is to form the straight and
parallel warp—threads with the weft into regular six—
sided meshes, as in Figs. 234.42, 2343, which represent
on an enlarged scale the production of the fabric by
the union of three sets of threads, one set consisting
of the warp-threads proceeding from the top down-
wards, ina waving line; the second set runs towards
the right, and third to the left; the second and
third being weft-threads which cross each other ob-
liquely in the centre, between each two meshes

throughout the series; in fact, one set of weft-threads
draws the warp-threads to the right, and the other to


Fig. 2341.
the left. After the warp-
threads have been laced
twelve times by the weft-
threads, the latter is
moved sideways through
one interval of the warp-
threads. Lace-making
thus differs form weaving
in this, that the threads F 1117-23437
of the warp are not alternately raised or depressed
for the passage of the weft, but are shifted sideways
to the next pair, to which they become united by
means of the weft-threads, which also work in pairs,
each of them entwining two individual threads at once.
The thread used in the lace-frame is wound upon
the roller for the warp, and upon small bobbins pecu-
liarly formed for the weft. In warping, the threads
are first wound upon a reel, from which they are trans-
ferred to the roller or thread-beam, and which extends
the whole length of the thread-beam; a portion of the
reel and of the thread-beam is represented in Fig.
2344a. The bobbins for the weft-threads are shown
in Fig. 2345, in front, and in section. Each bobbin




Fig. 2345.
Fig. 2344.
is formed of two thin brass discs with a hole in the
middle of each, riveted together, so as to leave a.
circular groove between them for the reception of the
thread. In the centre is a square hole for receiving
a square spindle or rod, for preventing the bobbins
from turning round during the process of winding the
thread. From 100 to 200 bobbins are thus spitted,
and the thread is conducted from a drum through the
slits of a brass plate, corresponding in number with
that of the bobbins to be filled. On turning round
the spindle which contains the bobbins, the drum re-
volves and delivers its thread, the surface of the table
over which the train of thread passes is painted
black, so that the winder immediately detects the
breaking of a thread. As many as 1,200 bobbins
may be required for one machine, and in order that
the same quantity of thread, usually about 100 yards
for each bobbin, may be wound upon each spitful, a
WEAVING.
971
hand moving round a dial-plate is made to indicate
the quantity wound.
Each bobbin is next inserted in a small iron frame,
called the bodbz'n-carrz'age, Figs. 234-6, 2347 , where it
is shown in the front
and side section, the
hole 11 in the car-
riage receiving the
bobbin, the groove-
borders of which fit
the narrow edge e e,
of the hole, and the
spring preventing
the bobbin from fall-
ing out, but allow-
ing it to turn round
and give off its thread when gently pulled. The
thread is conducted through the eye at the top of the
carriage.
The working parts of the lace-frame are shown in
the vertical section or end view, Fig. 2350; D, is the
thread—beam containing the warp; and at the top of
the frame is a similar roller 1)’ for receiving the
finished work. The warp threads are extended in
vertical lines between these two rollers. G e are
guide—bars extending the whole length of the machine
with slits in their edges, through which the warp-
threads are conducted in two rows, one on each side,
to the eyes 6 e of needles, one of which is shown se-
parately in Fig. 2348. Each guide-bar, which con-
tains a range of these needles, equal to one-
half the number of threads in the warp, has
a skaygirzg or slightly shifting motion to the
right or to the left, to allow the bobbin-
threads to pass on the right or on the left
of the warp as many times as is necessary
to produce the twist. The number of bob—
bins, with their carriages, is equal to the
number of the weft—threads, and as these
have to pass through the narrow intervals of the
warp-threads, they are arranged in a double line in
two rows, as at c c’, Fig. 2350, on each side of the
warp-threads. The bobbins are supported between
the teeth of a sort of comb c c’, a portion of which is
shown separately in Fig. 23110. The bobbin carriages
are each furnished with a groove gg, Fig. 2350, for
the reception of the teeth of the comb. There is one
comb on each side of the warp, and the free ends of
the teeth in the opposite combs stand so near to each
other as to leave a space only just sufficient for the


Fig. 234?.
Fiy. 2 H6.
Fig. 2348.
proper motions of the warp—threads between them ;»
hence the carriages, in passing across through the
intervals of the warp, reach the back bolts before they
have entirely quitted the front ones. The carriages
are driven alternately from one comb to another by
two bars 56, and when one of the lines of carriages
is pushed nearly across the intervals of the warp, the
foremost of their projecting catches a’ c’, Fig. 2350, is
laid hold of by a plate 10 attached to a horizontal
shaft s, which pushes it quite through. The beam to
which the combs are attached admits of being shifted
a little sideways, either to the right or to the left ; by

which motion the relative position of the opposite
combs is changed by one interval or tooth, so as to
transfer the carriages to the next adjoining teeth.


_-
u“ F
mnhw“ - ) ©
' A


/
r
‘I
\ vi?

Fig. 2350. wonxme PARTS or LACE macmnns.
By this means the whole series of carriages makes a
succession of side steps, to the right in one comb
and to the left in the other, so as to perform a species
of countermarch, in the course of which they are made
to cross each other, and then again to twist round
about the vertical warp threads, and thus to form the
meshes of the net. After the bobbins have moved
several times round about the warp threads, and en—
twined their threads with them, a point bar BB,
Fig. 2350, containing a row of pointed needles, one
of which is shown separately in Fig. 2351,
falls between the warp and weft threads,
and carries the interlacements of the latter
up to form a new line of holes or meshes in
the lace. Here it remains, while the other
point bar makes a similar movement to pro- ,
duce a second line of meshes. Thus the F i9‘ 2351‘
whole working of the machine is a constant repetition
of twisting, crossing, and taking up the meshes on
the point bar. As the lace is finished it is wound
upon the roller 1)’.
The beauty of bobbinmet lace depends on the qua-
lity of the threads, and on the equal size and hexa-
gonal shape of the meshes. The nearer the warp
threads are together, the smaller are the meshes and
an
WEAVING.
the finer is the lace. The number of warp threads in
a piece one yard wide, may vary from 700 to 1,200.
The fineness of the lace, or as it is called the gauge
or points, depends on the number of slits or openings
in the combs, and consequently the number of bob—
bins in an inch of the double tier. Thus gauge nine-
points means nine openings in one inch of the comb.
The length of work, counted perpendicularly, which
contains 240 holes or meshes, is called a male. Well-
made lace has the meshes slightly elongated in the
direction of the selvage. A circular bolt machine
produces about 360 racks per week, working 18 hours
a day, with two sets of superintendents. Bobbin net
is usually sent into the market in pieces of from 20
to 30 or more yards in length. The breadth is va—
riable. The narrow guillz'nys used for cap borders,
are worked in the same machine in many breadths at
once. They are all united together by a set of threads,
which are afterwards drawn out, and thus the quil-
lings become so many distinct pieces.
The English machine-made net is now confined to
point‘ ner‘, warp net, and dobdz'n net, so called from the
peculiar construction of the machines by which they
are produced. In a factory at Nottingham, visited by
the writer, the machines employed are limited to the
making of fancy net, both in wide pieces and in quil—
lings, the thicker thread or gimp being wrought into
the desired pattern by means of a Jacquard apparatus
attached to the frame. When the desired pattern
consists of a series of separate flowers, sprigs, &c.,
these are necessarily all connected by a single thread
of gimp passing between them, which single thread
is afterwards cut out by children, whose keen eyes
and nimble fingers enable them to use the scissors
with great precision and rapidity. Many establish-
ments, however, produce only plain net, in which the
pattern is afterwards worked by hand.
Nottingham has its pattern designers for lace, as
well as Manchester for cottons. The lace pattern is
drawn upon a block of wood, and then engraved in
the same manner as a wood engraving, those parts of
the surface being left in relief which are intended to
make a mark. The block is slightly moistened with
some coloured pigment, and is then impressed upon
the net a sufiicient number of times to cover its sur—
face. The lace runner then fills up the pattern with
her needle, the web being extended horizontally in a
frame for the purpose. Of late years lithography has
been introduced as a cheap substitute for engraved
blocks, to the great advance of the trade. A Go-
vernment School of Design established at Notting-
ham has had a highly beneficial influence in fostering
the talent of native pattern designers.
Lace running is a domestic employment, and the
young females engaged in it are not well paid. The
depressed condition of the embroiderers arises in a
great measure from the competition of the Belgians,
who have acquired a superiority in this department.
When the lace is embroidered it is carefully examined,
and all defective parts are marked by tying them
up in aknot ; the piece is then handed over to women
called lace anenders, who have a method of perfectly

restoring the damaged meshes. The lace menders
are a much better paid class than the lace runners.
The net is gassed before being embroidered; the
bleaching or dyeing takes place afterwards; the
dressing, rolling, pressing, ticketing, and making up,
closely resemble similar processes described under
GALENDERING.
The Jury Report contains a selected list of articles
made by the bobbin-net machines; and also of the
machines at present employed in the bobbin—net
trade. Of the former are, first, black silk piece—net
ornamented, shawls, scarfs, flounces, trimming-laces,
blondes in white and colours, some entirely finished
on the machines, others partly by machine, and em—
broidered afterwards ; secondly, cotton edgings, laces,
and insertions, linen laces in imitation of white pillow
lace, muslin edging and laces, fancy piece-net, spotted
net, and plait net, in imitation of the costly Valen-
ciennes lace; thirdly, curtains in imitation of the
Swiss curtains, bed-covers, and blinds, a branch 0.
industry only introduced in 1846, but already so ex—
tensive as to employ more than 100 machines, and to
elicit much excellence in design and texture; fonrflaly,
silk and cotton, plain and Mechlin grounds, blonde,
Brussels, or extra twist, a department employing
2,000 machines, and many thousands of work-people.
The forms of machine by which all this variety
of labour is accomplished are as follows: The “lea-
vers,” so called after John Leavers, the original con-
structor. By this machine most of the articles under
the first and second divisions are fabricated. The
“pusher,” so called from having independent pushers
to propel the bobbins and carriages from front to
back, instead of pulling or booking them as in other
arrangements. Shawls, scarfs, flowers, &c. of superior
quality, are made by this machine, and require to have
the pattern traced afterwards with a thick thread.
The “ circular,” so called from the bolts or combs on
which the carriages pass being made circular, instead
of straight, as in the straight-bolt machines. The
curtains, imitated from the Swiss, are made by this
machine, as are various descriptions of plain, spotted,
and fancy nets. “ Traverse warp machines ” are em-
ployed to a limited extent. They are so called from
the warp traversing instead of the carriages, and are
principally used for spotted lace, blonde edgings, and
imitation thread laces.
Such are the machines employed in the bobbin-net
trade; but there is another and a very important class
of machines, called warp machines, extensively em-
ployed in the lace trade. There are four persons for
whom this invention is claimed (about the year 17 7 5),
one of whom was Vandyke, a Dutchman,—-hence the
first articles manufactured, which were silk stockings
with a blue and white zigzag pattern, were said to
have the “Vandyke stripe.” For the common stock-
ing frame but one thread is requisite, while for the/
warp a thread for each needle was employed,—hence
it derived the name of warp machine. About 178A
a Nottingham mechanic considerably improved the
warp frame by the application of the rotary motion
and the cam wheels to move the guide bars, which
WEAVING.‘
97 3.‘
are still known in the trade as Dawson’s wheels. The
improved machine was, and still is, used for making
officers’ sashes, purses, &c. In 1796 a new fabric
was produced from the warp machine, and employed
for sailors’ jackets, pantaloons, and other articles, and
that fabric still known under the name of “Berlin”
is largely employed in the manufacture of gloves.
Warp machines were the first which produced orna-
mental patterns on lace, such as spots, bullet-holes,
&c. ; these had been previously embroidered or tam-
boured by hand. The application of the Jacquard
apparatus to the warp machine was an important
step taken by Draper of Nottingham in 1839, and led
to the production of a new and elaborate class of
goods by this means. Latterly the twist machine has
produced similar goods, and has in a great measure
supplanted the warp. So great have been the im—_
provements of late years in the English methods of
dressing lace, that it is now considered little, if at all
inferior to the best specimens from Lyons. Many
new kinds of manufacture have been produced by the
warp of late years, such as elastic woollen cloth for
gloves, and even velvet and plush made elastic for
the same purpose. Velvet, in combination with lace,
and many other novel forms of weaving, are also the
fashion of the day.
SECTION VII.—-ON HosIEnY, on STOCKING-FRAME
WEAVING.
In the process of knitting, whether by hand or by
machine, a single thread is entwined in such a manner
as to produce a tissue resembling cloth. Netting re-
selnbles knitting, inasmuch as the composition of a
net is also due to a single thread; but in a net, this
thread is tied into hard knots at those points where it
crosses upon itself, and thus forms distinct meshes;
while in knitting the thread forms a succession of
loops, which run into each other without knots. An
injury to one mesh in a net-need not affect any of the
other meshes; but the breaking of one loop in a
knitted fabric, leaves the whole tissue liable to come
unlooped. Knitting and netting are familiar occupa-
tions, much more easy to learn than to describe in
words. Netting is an ancient invention, nets being
referred to in the prophetical writings of the Old
Testament. Knitting is of more recent date. The
knitting of stockings is supposed by Savary to have
been invented in Scotland in the 16th century, from
the circumstance that when the French stocking
knitters in 1527 became numerous enough to form a
guild, they chose St. Eiacre, a native of Scotland, for
their patron saint. There is also a tradition, that the
first knit stockings seen in France were brought from
Scotland. Other writers adopt the opinion, founded
on a passage in Howel’s “History of the World,”
(printed in 1680-85,) that the art of knitting stock—
ings came from Spain. He says that “ Henry VIII.
wore ordinary cloth-hose, except there came from
Spain, by great chance, a pair of silk stockings.
King Edward his son was presented with a pair of
long Spanish silk stockings, by Sir Thomas Gresham,
his merchant, and the present was taken much notice

of. Queen Elizabeth, in the third year of her reign,
was presented by Mrs. Montague, her silk woman,
with a pair of black knit silk stockings, and thence-
forth she never were cloth any more.” This informa-
tion is confirmed by Stow, who names the Earl of
Pembroke as the first nobleman who wore worsted
knit stockings. In 1564, William Rider, an appren-
tiee of Master Thomas Burdet, having seen in the
shop of an Italian merchant a pair of knit worsted
stockings from Mantua, borrowed them, and made a
pair exactly like them, and these are said to have
been the first stockings of woollen yarn knit in
England. ,
Not long after the art became known in England,
the knitting of stockings was adopted as a domestic
employment. When Queen Elizabeth visited Norwich,
in 1579, several female children appeared before her,
some of whom were spinning worsted yarn, and others.
knitting hose fromthe same material. Not many
years later an attempt was made to expedite the
process by the aid of machinery. The history of the
stocking-frame is rather difficult to trace; but there
exists a picture in the Stocking Weavers’ Hall,
London, with the following inscription: “In the
year 1589, the ingenious William Lee, Master of Arts,
of St. John’s College, Cambridge, devised this profit-
able art for stockings, (but being despised, went to
Il‘rance,) yet of iron to himself, but to us and others,
of gold; in memory of whom this is here painted.”
The picture represents a man pointing to an iron
stocking-frame, and addressing a woman who is knit--
ting with needles by hand. The story of this William
Lee, or Lea, is that he was a native of VVoodborough,
in Nottinghamshire; and that when at Cambridge he
married, contrary to the statutes, and was on that
account expelled from the University. His prospects‘
, thus destroyed, he found himself without means of
support, except that derived from his wife’s skill in
knitting stockings. It then occurred to him that
artificial fingers might be contrived for knitting many
loops at once; and, having convinced himself of the
possibility of this plan, he devoted much time and
labour to its accomplishment. When success at
length crowned his efforts, he instructed his brother
James in the use of the frame, and proceeded to make
an application of his invention, first at Calverton, a
village near Nottingham, and shortly afterwards in
London. In the latter place he succeeded in obtain-
ing the notice of Queen Elizabeth, who is said to
have actually visited him in order to see him work at
his frame. The Queen expressed her disappointment
' that he was making woollen instead of silk stockings,
and refused to give him either a grant of money or
a patent of monopoly, on the ground that the inven-
tion would deprive the poor of employment. About
the year 1596-7, Lee succeeded in making plain silk
stockings from a twenty-gauge silk frame. He erected
nine frames, which were worked by apprentices,
chiefly consisting of his relatives; who esteemed it
so high an honour to belong to the new craft, that
they were their working needles, with ornamented
silver shafts, suspended from a silver chain at their,
97$
WEAVING.
breasts. Lee failed in procuring a patent ; and some
time afterwards, when Sully came to London, as
ambassador for Henry IV. of France, he made Lee
very splendid offers to induce him to remove himself
and his machinery to France. The disturbed state
of that country led him at first to decline the offer;
but some years afterwards, finding that the King,
James 1., was even more unfavourably disposed to
his invention than Elizabeth had been, he removed
the whole of his machinery and workmen to Rouen,
in Normandy. Having established his frames in that
city, he went to Paris, and had the honour of an
interview with Henry IV. Everything seemed to
promise success; but the troubles consequent on the
murder of the king destroyed Lee’s prospects; he
was proscribed as a Protestant, and was obliged to
seek concealment in Paris, where he died in poverty
and distress. Lee’s brother, and all the workmen
except two, returned to England. The two who re-
mained were allowed to retain one frame; the other
frames were brought to England, and one of them
appears to have been sold to a person named Mead,
in the city of London. The attempt which had been
made by Sully to plant the infant manufacture in
France, was also made by the ambassador from Venice
in favour of that city, then the most commercial and
manufacturing in the world. He paid Mead the sum
of 5001. for the purchase of his frame and his per-
sonal superintendence of it at Venice. But as Mead
could not make his needles, nor repair his frame, his
work was soon brought to a stand. The Venetians
also failed in their endeavours to copy the machine;
and as Mead, at the expiration of his engagement,
insisted on returning to London, the whole scheme
of Venetian frame-work knitting was abandoned.
This was about the year 1621.
After the return of Lee’s workmen to London,
they did not remain idle. Through their means the
number of frames and frame-work knitters increased
rapidly; so that early in the 17th century, the
frame-work knitters resident in London, which was
then the principal seat of the manufacture, formed
themselves into a company, and petitioned Cromwell
to constitute them a body corporate. The Protector
does not appear to have paid any attention to this
petition; but immediately after the Restoration it
was renewed, and at length, in 1663, the petitioners
obtained a charter, which came into operation in the
following year. .
This charter gave a great impetus to the trade in
London and its neighbourhood; the prices of admis-
sion to the Company were low, and the number of
applicants was large. The master, wardens, clerks,
assistants and deputies were the only parties who were
electors; and the assistants at the end of forty years
were composed of frame-work knitters and of persons
who had bought in for the sake of the vote. The
Company had a large income, arising from the various
fees, and from the sale of freedoms and livery; but
as they were restricted from holding more than 1001.
per annum, they managed to get rid of the surplus
in feasts and gorgeous processions, such as were

indulged in by other trade companies, to the great
delight of the populace. The great day for these
shows was, as at present, the 9th of November,
when the Lord Mayor was installed. The trade had
by this time extended to Leicester, Nottingham,
and Derby, where the companies were governed by
the laws of the London Company. These having
been, on some occasions, rigorously exerted, mis-
understandings arose, and attempts were made to
throw off the authority of the metropolis. These
attempts became successful in 1753, when a decree
of the House of Commons virtually extinguished the
monopoly. About 1756 Jedediah Strutt invented a
machine for making ribbed-stockings, and with his
brother-in-law, Mr. Wollatt, of Derby, took out a
patent for the same. This improvement led to
others, such as open—work mittens, and fancy articles
in the stocking stitch. With this exception the
stocking frame seems to have reached a nearly per-
fect state about the year 1714:, and has continued up
to the present time only to be worked by hand, not
because it is incapable of the application of steam
power, but on account of the abundance and cheap-
ness of hand labour. Of late years circular hosiery
frames have been introduced, by means of which
ladies’ skirts, stockings, and other articles, have
been manufactured in great variety. The frames in
the Great Exhibition, by M. Claussen and M. Jacquin,
were nearly identical; they had vertical sinkers, ec-
centric depressers, and tucking pattern-wheels, and
were capable of producing fabrics of great variety and
beauty. The circular frames of M. Berthelot were
of more complex structure : the sinkers were arranged
in a horizontal position, and revolved with the
frame; but these machines were capable of producing
finer fabrics than the preceding, and with such mate-
rials as flax and silk.
Frame-work knitting is, for the most part, a do-
mestic branch of industry. The stocking-weavers of
Nottingham and its neighbourhood live, in general,
in their own houses or rooms, and are furnished with
frames, either by the wholesale dealers or hosiers,
who pay after a certain rate for work performed; or
by a class of middlemen, called master stocking-
makers, who charge a certain sum for the use of their
frames, without reference to the quantity of work
performed. These frames are protected by law from
distress for rent and from execution for debt; the
master stocking-makers collect the work, pay the
operatives, and transfer it to the wholesale dealers.
In some instances, however, there is an approach to
the factory system; when one master stocking-maker
is the owner of several frames, which he collects
under one roof, and engages operatives to work at
them, paying for the amount of work produced.
The stocking-frame is a complicated machine, the
number of moving parts being large, and collected
together in a small compass. Nice workmanship is
required in the construction of a frame, and any little
derangement, such as the bending of a needle, is fatal
to its action. The separate parts are made by the
flame-mitt, and are put together by the setters-2Q),
WEAVIN G.
975
who are also frame-menders; but in ordinary cases,
the stocking-maker keeps his own frame in working
order.
In attempting to describe the stocking-frame, we
must again refer to the process of hand-knitting, in
which two straight wires, or knitting-needles, are
used, and the operation consists in forming a series
of loops upon one needle and inserting them within
another series contained upon the other needle. This
is effected by four movements :-—-1. By pushing the
right-hand needle through the first loop of the left-
hand needle. 2. By turning the thread once round
the right-hand needle, to form a new loop. 3. By
drawing the new loop through one of the former
series. 41. By pushing the old loop off the left-hand
needle. When one row of loops is completed the
needles are made to change hands, and a new course
is commenced.
In knitting by the stocking-frame a number of
needles is employed, varying according to the fine-
ness of the work, from 15 to 40 being contained
in an inch; the largest number being used for
the finest stockings. They are made of iron wire
of the shape represented in Fig. 2352, with a hook or
%
(“a
W
Fig. 2352. NEEDLE or run ncrunr. srzn.
barb at the end, and the sharp ends very fine and
delicate. There is a small cavity or groove, shown in
Fig. 2353, punched or sunk in the stem of each
needle immedi-
Fig. 2353. ately beneath the
barb, of sufficient depth to receive the point when
pressure is applied upon the hook to bend the barb
down. The barb then becomes a closed eye, and if
a thread is looped over the stem of the needle and

‘drawn forwards while the barb is thus closed, it will
pass over the barb of the needle and come off at the
end of it: but if the thread is drawn forwards while
the barb is open, it will be caught under the hook,
and thus be detained. The principal action of the
machine depends upon this circumstance. The de—
pression of the barbs of the needles is produced by
the edge of a prewar-bar, shown in end section, Fig.
2352, which is extended horizontally over the whole
length of the needles, and is acted upon by pressing
the foot upon the middle one of the three treadles of
the machine. '
The needles are fitted into the frame by being first
cast into tin sockets, called leads. The form of the
needle, when complete and fitted to its place in the
frame, is shown in Fig. 2352. In front of the needle-
bar is a small piece of iron, called the verge, to regu-
late the position of the needles. When placed upon
the bar, resting against the verge, another plate of
iron, generally lined with soft leather, is screwed
down upon the sockets or leads, in order to keep them
all fast. When the presser-bar is forced down upon
the barb, the needle is shut, and when the presscr-
1“
bar rises, the barb rises or opens by its own elasticity.
Fig. 2354! represents a single thread formed into a
number of loops by arranging it over an equal num-
ber of parallel needles; these are retained or kept


Fig. 2354.
in the form of loops by being drawn or looped
through similar loops formed by the thread of the
preceding course of the work. This is the common
stocking-stitch used for plain hosiery; and the whole
operation of the common stocking-frame consists in
the formation of a series of loops, and then drawing
them successively through a series of other loops, as
long as the work is continued. There are many dif-
ferent kinds of stocking-stitch used for ornamental
hosiery, each requiring a different frame or machine
to produce it. -
The next part of the machine requiring description
is that for forming the loops. This consists of two
parts, the jack-sinkers and the lecithin/cars. The jack-
sinkers consist of a succession of horizontal levers or
jacks, j, Fig. 2355, moving upon a common centre;
each jack is furnished with a joint, from which hangs
a very thin plate of polished iron called a sin/tar.
One of these jacks and sinkers is allotted to every
alternate needle in the frame, the sinkers hanging
down between them. The other ends of the jacks are
tapered to a point; and when the jacks are in their
horizontal position, they are secured by small iron
springs, s, each having a notch to receive the point of
the jack.
The lead-sinkers resemble the jack-sinkers, but are
differently attached; for while the jack-sinkers admit





Fig. 2355.
of being raised or lowered separately, the lead-sinkers
are all fixed to one bar, called the sinker-bar, and
must be raised or lowered all together. The lead-
sinkers are placed alternately between the jack—
sinkers; hence it follows, that between every two
sinkers throughout is one needle.
The jack-sinkers being elevated_so as to bring their
976
WEAVING.
hips, N, above the level of the needle, the thread is
loosely thrown under these nips. * Now, it is obvious
that on lowering the jacks a series of loops will be
formed; see Fig.23541; but if the jacks were all
lowered at once, there would be danger of destroying
the thread, an accident which is avoided by a very
ingenious contrivance. A straight iron bar, 6, called
the slur-tar, is extended beneath all the jacks, and
upon this a piece of metal, 8, called the slur, travels
with rollers ; motion is given
to it by a cord attached to
each side of it, passing over
a pulley, p, and connected,
by means of a wheel, with
the two outer treadles of the
frame. By this means, the
slur is made to travel back-
wards and forwards, thus
lowering only one jack-sinker
at a time, and depressing one
, loop of thread between every
pair of needles. The loops
thus formed are of double
the depth required; in order,
therefore, to bring them to
the proper size, and to throw a loop between every
two needles in the frame, the workman next de-
presses the lead-sinkers all at once, and their nips,
N, carry down the thread between the remaining
needles in loops. While this is being done, the jack-
sinkers are made to rise up as much as the lead-
sinkers are depressed; thus making all the loops
throughout of the same size, and forming a loop
between every two needles. This row of loops is
next driven back upon the needles, so as to come
below the arch or opening of the sinkers, a, Fig. 2356.
Here the loops are entirely removed from the action
of the sinkers, and the workman proceeds to form a
new row in front of the former, by a repetition of the
process already described. The second row of loops
is then brought forward, so as to be under the barbs
or hooks of the needles. The presser-bar is next
made to close the barbs with the thread within them.
The first formed loops are now brought forward from
under the arch, upon the closed needles, and are
made to pass over the ends of the needles, and the
new—formed loops within them. By this means the
loops of What was the upper or last course of the
finished work became secured, and the loops under
the barbs now become the upper course, and are
preserved from unravelling by the needles, one of
which passes through each loop; and these loops will
not be drawn ofi from the needles until there is
another row of loops prepared and ready to be drawn
through them. '
This description of working the courses of loops
within each other will perhaps be more intelligible if
we follow the workman in another course. Prepara-
tory to this, the loops of the last course, and by
which the work is suspended from the needles, must
be pushed back upon the stems of the needles, so as
to come into the arched or open part of the sinkers,


Fig. 2356.

a; another row of loops is then formed and brought
under the barbs; the barbs are then closed, and the
row of loops under the arch is brought forward over
the barbs, and over the ends of the needles, whereby
the loops under the barbs are drawn through the
loops which pass over the barbs, and thus, by a sort
of circular motion, a web is formed which hangs
down from the needles. When the piece is of con-
siderable length, it is wound upon a roller contained
in an iron frame, the weight of which is sufficient to
keep the web properly stretched. Thus the various
movements of the frame required in stocking weaving
are as follows :—-Supposing the workman has put the
work back on the needles, preparatory to another
course, the first movement is the gatherz'hg of the
thread. The thread is lightly extended across the
needles, beneath the nips N of the sinkers, and by
pressing the slur-treadle the jack-sinkers are de-
pressed, one by one, so as to form double loops; this
is called “ d1 having the jaahs.” The second movement
is called sin/ring. The whole row of lead-sinkers is
depressed, while the jack-sinkers rise, whereby the
thread is carried down into a loop between every two
needles. The third movement is to bring the thread
under the barbs of the needles. The fourth movement
is to bring the work forward from the stems of the
needles towards the barbs. Fifth, closing the barbs
by the pressure of the presser-bar, and drawing the
loops last made through the finished loops of the
work. The finished loops are drawn over the barbs,
and quite off from the needles; this draws the
finished loops over the loops last made, which remain
in the barbs of the needles.
There are certain details respecting the stocking
frame, which, for the sake of clearness, have been
omitted in the foregoing description. A few of them
may now be noticed. The bobbins which supply the
workman with thread are, in the case of silk hose,
contained in a small covered barrel at the side of the
frame, having in it a small quantity of water, the
evaporation of which keeps the thread sufficiently
damp for working. It is drawn out as it is wanted,
through a hole in the cover of the barrel. In cotton
hose, the bobbin containing the thread is merely
placed on an iron spindle, fixed in one of the upright
beams of the frame. The jacks with their springs,
and the slur-bar, are mounted upon a strong bar
called the camel, which moves upon four wheels,
forming a sort of carriage, capable of being pushed
backwards and forwards through a small space. In
bringing a row of loops forward, so as to be under
the barbs or books, the carriage is simply drawn
forward, which advances all the sinkers together,
and their points 12, Fig. 2356, push forwards the
thread till it comes into the barbs, and these prevent
it from coming off the needles. The jacks also admit
of being depressed by the workman’s hand, and they
recover their position when relieved, by the action of
a steel spring. In pushing the work back upon the
stems of the needles so as to gome into the arched or
open part of the sinkers, the hosier depresses the
sinkers low enough for their point p to enter between
WEAV'IN G—WEIG-HIN (ii-MACHINE.
977
the needles, and then by pushing the sinkers back,
the thread is driven back with them.
The fineness of the work depends on the number of
loops which the thread makes in any given length, and
this will be equal to the number of needles and
sinkers in the same space. Thenumber of needles in
an inch is called the gauge of the frame, and when
once this is fixed, it can never be altered; hence the
work which it produces will always be of the same
degree of fineness, so that when a stocking—maker has
once purchased his frame, he is always limited to the
same kind of work; he may, however, make it a
little more dense or more slight, by drawing the loops
very close, or by allowing a greater quantity of
thread, and making the loops longer. The length of
the loops will depend upon the depth to which the
nips of the sinkers descend between the needles,
when they carry down the thread into loops. To re-
gulate this depth, the falling bar, or that piece which
sustains the leads containing the row of needles, is
made to rise or fall a slight quantity, by means of
two adjusting screws. When the piece of work is
finished and taken off from the frame, the last made
row of loops must be secured by running a thread
through them, or by some other means, or they
would escape by drawing through the preceding
loops, and these in like manner would release the
previous ones, until the whole became unravelled.
The working of the frames is one of considerable
toil, but does not for ordinary goods require much
skill and training. The employment is said to be in-
jurious to the sight.
Snc'rron VIII.--Srarrsrros.
The statistics of the important objects of manufac-
ture, noticed in the preceding sections, are of great
interest, forming as they do some of the principal ex“
ponents of the industry of a great commercial nation.
Limited space, however, will not allow us to ‘do more
than quote a few general results. In the year 1852,
the total declared value of British cotton manu-
factures, including twist and yarn, amounted to
29,878,0871. Of this amount, the British East
Indies receive to the value of 5,358,4421. ; the
British West Indies, 11725171.; British North
America, ‘16955111.; Australia, 337,960L; British
South Africa, 278,9771. ; United States, 2,681,025L;
the Hanseatic Towns, 2,87451061. ; Holland,
2,042,888L; China, 1,905,321L; Brazil, 1,891,865Z.;
Turkey, 1,779,693Z.; Portugal, 635,879L; Chili,
571,310L; Naples, 54457021.; Sumatra, Java, &c.,
5115681.; Russia, 195,150l.; France, 1863,2161.
The following articles were- exported in the years
ending 5th January, 1852, 1853 :—

Declared value.
Dcclared value.
1852. 1853.
Cotton manufactures, exclusive 0 } £22 049 902 £21 704 18,1,
lace and patent net ' w ' i
Lace and patent net 558,350 580,100
Thread for sewing ‘154,347 506,716
Stockings 197,367 237,342
Other descriptions 195,544 272,930
Cotton yarn 6,634,026 6,655,344
Linen manufactures, exclusive of)~ 3,822,935 3,857,030
lace of thread VOL. II.

1852. 1853.
Lace of thread 5,602 4,060
Thread for sewing .. 258,856 838,821
Other descriptions 20,003 12,439
Linen 951,426 1,144,521
Silk,stufi‘s, handkerchiefs, and ribbons 531,552 546,651
Silk stockings 26,307 25,162
Other descriptions 193,518 254,221
Silk mixed with other materials :—
Stuil's, handkerchiei's and ribbons... 34 7,874 ‘ 289,484
Stockings 4,758 4,511
Other descriptions........................ 26,389 36,682
Thrown 57,803 192,467
Silk twist and yarn 138,577 201,002
Woollen manufactures, by the piece... 5,251,184 5,412,347
--——-—---~-—-— by the yard.... 2,822,961 3,014,705
Stockings..................................... 111,467 117,032
Other descriptions 188,571 181,561
Woollen yarn 1,481,544 1,419,933
WEDGE. See STATICS AND Dynamos.
WEFT. See Wnavme.
WEIGHING-lldACI-IINE. A machine constructed
near a turnpike, for the purpose of ascertaining the
weight of the loads on w. cons and carts which pass
along the road. In order to prevent the roads from
being toomuch worn, a certain weight for each
breadth of wheel has been fixed by Act of Parliament,
and the weighing-machine is necessary in order to
ascertain that this weight has not been exceeded.
W eighing-machines have been so contrived, that the
carriage may be lifted off the ground, and hooks at-
tached to a large steelyard, of which the fulcrum is
raised by a combination of tooth and pinion work,
moved by a winch handle. That arrangement, how-
ever, is to be preferred, which allows the wagon or
carriage to be drawn on a wooden platform which is
even with the surface of the road, and which forms,
as it were, the scale-pan of a peculiarly constructed
balance. The platform is placed over a pit, and so
arranged as to move freely up and down without
touching its walls. It rests upon four levers, A B o D,
Fig. 2357, converging towards the centre, and each
moving on a fulcrum, A B c D, and fixed firmly in each




Fig. 2357. WEIGHING-MACHINE.
corner of the pit. The platform rests by its feet
a’ c’ d’, upon steel points aired. The four levers
are supported at the point F, under the centre of the
platform, by a long lever en, resting upon a steel
fulcrum at F‘; its further end e being carried upwards
into the turnpike-house, where it is connected with
one arm of a balance; while a scale suspended from
the other arm carries the counterpoise or power, the
amount of . which indicates the weight of the wagon
3 n
978
WEIGHING~MACHINE~WEIGHTS AND MEASURES.
on the platform. As the four levers, A :B c n, are equal
and similar, the effect of the weight distributed
among them is the same as if the whole weight rested
upon any one of them; hence, to ascertain the con-
ditions of equilibrium, we have only to consider one
of these levers, such as AF. If the distance from
A to F be ten times as great as that from A to a, a
force of 1 pound at F would balance 10 at a, or on
the platform. So also, if the distance from n to G
be ten times greater than the distance from the ful-
crum n to F, a force of 1 pound, applied so as to
raise up the end of the lever G, would counterpoise a
weight of 10 pounds on n; so that as we gain ten
times the power by the first levers, and ten times
more by the lever E G, a force of 1 pound tending to
raise G, will evidently balance 100 pounds on the
platform. If 10 pounds be placed in the scale-pan to
which G is attached, it will express the value of 1,000
pounds on the platform. In this way, wagons and
carriages can be weighed without difficulty. When
the platform is not loaded, the levers are counter-
poised by a weight applied to the end of the last
lever.
The weighing—machine for goods in use at railway
stations consists of a compound lever, or a composi-
tion of levers, as in Fig. 2358, which consists of three
‘ ‘F i; levers, two of the se-
l is 51 cond kind, A n, A" r”,
and one of the first
kind, A’ n’. The power
P, acting upon the
lever Ar, produces a
downward force, D,
which bears to r the
same proportion as
Arto BF. IfAr be
8 times BF, the force
at B is 8 times the
Fig. 2358. power P. The arm
A’ r’ of the second lever is pulled down by a force
equal to 8 times the power of P; and this will
produce a force at B’ as many times greater than A’,
as A’ n’ is greater than 3'1’. So that if A’ n’ be
10 times B’ n’, the force at B’, or at A”, will be
10 times that at A’ or B; but this last was 8 times
the power, and, therefore, the force exerted at A” will
be 80 times the power. So, also, it may be proved
that the weight W is as many times greater than the
force at A", as A" r” is greater than B" r”. If A” r"
be six times B" r", the weight w will be 6 times the
force at A". As this is 80 times the power P, the
weight when in equilibrium will be 480 times the
power. We may obtain the same result more ex-
peditiously by dividing the product of AP, A’ F’, and
A” F", by that of B 13‘, B’ r’, and B" F". Thus, if the
three former distances were 16 inches, 20 inches, and
18 inches; and the three latter, 2 inches, 2 inches,
and3inches; then16>< 20x18+2 x2>< 3:41.80.
The ratio of 4180 : 1 is said to be compounded of the
three ratios, 8 : 1, 10 : 1, and 6 : 1. Thus, it will be
seen that when a system of this kind is in equilibrium,
the ratio of the power to the load is compounded of









the ratios subsisting between the arms of each lever;
or, in other words, the power multiplied by the con-
tinued product of the alternate arms, commencing
from the power, is equal to the weight multiplied by
the continued product of the alternate arms, beginning
from the weight. See BA'LAncn—SrArrcs AND Dr-
NAMIos—RoAns AND BArLaoAns.
WEIGHTS AND MEASURES. All the common
books of arithmetic, and most almanacs and pocket-
books, give usefnl tables of weights and measures, with
which most readers are familiar. Instead of giving
those tables in detail here, we shall offer a few ex-
planations concerning the standards adopted ; and as
the French language is now more extensively known
‘in England than that of any other foreign country,
we shall present a few equivalents in English and
French measures.
Until about thirty years ago, the standards of
weight and measure in England were most irregular
and unconnected. The standard of length was a
metal yard, which had been in the custody of the
Clerk of the House of Commons since the year 1760.
In Scotland, the Scots ell, measuring 37-;- English
inches, was a standard whence the Scots acre was
derived. The standards of weight were the Troy
pozmal which had been constructed in 1758, and the
Aooz'rclapois pozmol, the former of which bore to the
latter the ratio of 5,7 60 grains to 7,000. The Scots
troy poaml differed both from the English troy and
the avoirdupois; and, moreover, it differed in different
parts of Scotland. The standard of liquid measure
was the gallon, which was, however, of unequal size
for ale, wine, and corn; and the _pz'als and firlols,
which formed the units of measure in Scotland, were
equally irregular. The standard for dry goods was
generally heaped measure, which varied of course
according to the degree in which it was heaped.
Many of these inequalities were removed by an
act of Parliament passed in 1824. The old yard is,
by this enactment, retained as the standard of length;
and in order to verify it in case of destruction, a
ratio was established between its length and the
length of a pendulum. It was found that a pendu-
lum, vibrating seconds in the latitude of London,
measures 391393 of such inches as are marked on
this standard yard. The old troy pound and avoirdu-
pois pound are also retained (having the ratio 5,760
to 7,000, or 1414*. to 175); and, in the event of the
standard troy pound being destroyed, a ratio has been
established between troy weight and the weight of a
certain bulk of water. A cubic inch of distilled
water, at a pressure of 30 inches, and a temperature
of 62° F., is found to weigh 252'4158 troy grains.
The new standard measure of capacity is the imperial
gallon, equal in bulk to 10 pounds avoirdupois weight
of distilled water at 30 inches barometric pressure,
and 62° F. This new gallon is larger than the old
wine gallon and corn gallon, but a little smaller than
the old ale gallon. The pee/e, bushel, and gaan‘er, are
all derived by multiples of this imperial gallon ; and
the gaarl, plat, and yell, by sub-multiples. For
familiar purposes it may be useful to know, that a
WEIGHTS AND MEASURES—WELD’.
070
"do Fah. above melting ice.
vessel forming'a 61,- inch hollow cube would contain
almost exactly an imperial gallon. Another act was
passed in 1834', confirming and strengthening the pro-
visions of the’former act,‘ and also prohibiting the
further use of heaped measure; it also abolished (so
far as an act of Parliament can abolish them) local
and customary weights and measures throughout the
kingdom, such as the Wine/tester bus/tel, the Seols ell,
the alone (of any other weight than 1dlbs.), the bell,
&c. At the time when the Houses of Parliament
were destroyed by fire, the old standard troy pound
was much injured, and the standard yard was
altogether lost ; measures have since been taken to
reproduce equivalent standards, adhering to the
actual values as established in 1825. '
In France, the weights and measures have under-
gone a more marked change than in England. There
was no relation between the ,ez'ed, the unit of length,
and the lime, the unit of weight; and weights and
measures of the same name differed greatly in differ-
ent parts of the country. In 1788, the government
‘ordered a scientific inquiry to be made into the best
mode of reforming the whole affair; but it ‘was many
years before the “new melm'cul system,” as it is
called, was completed and brought into public use;
and even now, in country places, the old measures are
still partially retained by those who are too ignorant
or too prejudiced to appreciate the advantages of the
new. This new system ‘rests on a scientific basis.
All weights and measures are derived from the metre,
which is ‘equal to Tumlb—Jm-fith of a quadrant of the
‘earth’s circumference, from the pole to the equator.
To this word metre are prefixed the syllables, deeu,
peelo, kyle, and myrz'u, to denote 10, 100, 1,000, and
10,000, respectively; or deed, ceulz', and uzz'llz', to de-
note 116th, T-é-Uth, Tvlimth. This is long measure ; and
from it is derived laud measure, by calling 100 square
metres an are. They obtain dry and liquid measure by
making the unit or standard a litre, equal incapacity
to a cubic decimetre; while, for solid measure, the
‘ standard is a slere, equal to a cubic metre. Lastly,
to complete the series, weight is allied to the metre,
by making the lei-logmmme to be equal to the weight
of a cubic decimetre of water, at the temperature of
All these units, by the
‘use of the prefixes, deeu, deal, lie'clo, mm, &c., become
applicable to any weights or any measures, large or
‘small ; and as the multiple 10 connects all the larger
and smaller measures with the unit, the whole be-
' come easily susceptible of decimal computation. Not-
"withstanding the advantages of' this complete system,
however, the French government have found it ex.
pedient to permit the limited use-of the older weights
and measures; and thus we still frequently meet with
pieds, pouces, lz'gues, dunes, t‘oz'ses, lieues, arpeuls, cordes,
vergées, loz'ssedua', pz'ules, louueuua', 'lz'eres, gree, grains,
ouees, &c.
The following comparative statement of English
and French measures will be found useful ;—
MEASURES OF LENGTH.
ENGLISH. :ennncn.
Inch, Pouce, (1,‘, th of a yard)...... 2'539954 centimetres.
Foot, Pied, (dd 0.’. a yard) ........... 30479449 decimetres.

ENGLISH. FREN on.
Yard, Imperial 0'913188348 metre.
Fathom (2 yards) P82876596 metre.
Pole or perch (5g yards).............. 5'029'11 metres.
Furlong (220 yards) 201‘16437 metres.
Mile (l760yyards) 1609'31119 metres.
FRENCH. mveusn.
Millimetre .. o-oscsr inch. ‘
centimetre 0-393708 inch.
Decimetre................................. 3'937079 inches.
39'37079 inches.
Metre ...... . { s-2sosoe2 feet.
1-093638 yard.
Myriamétre 62138 miles
SUPERFICIAL MEASURES.
I nnenrsn. _ r'nmvcu
Square 0836097 square metre.
Rod (square perch) 25'291939 square metres.
10'116775 ares.
0'404671 hectare.
Reed (1210 square yards)............
Acre (4840 square yards)
FRENCH. ENGLISH.
Square metre 1196033 square yard.
II'UIIIQIII'lilllliblillIOIOI'lOl‘llIDOIIO
I'D I'DIIIDIUQU'II. III GO‘III ‘IIIII ‘I.
MEASURES
ENGLISH.
Pint (g-th of a gallon)
Quart (3; th of a gallon) Gallon, imperial........................
Peck (2 gallons)................. .
Bushel (8 gallons)......................
Sack (3 bushels) Quarter (8 bushels) Chaldron (12 sacks)
FRENCH.
OF CAPACITY.
nnnncn.
0'567932 litre.
1'1-35864 litre.
454345797 litres.
9-0869159 litres.
36'347664 litres.
1'09043 hectolitre.
2'90781’3 hectolitres.
13'08516 hectolitres.
ENGLISH.
[P760773 pint.
10'2200967 gallon.
2'2009668 gallons.
22'009668 gallons.
o no." on Inc on! lolilbcu “Inc 00' on Oil
a". ‘10". villus carcasses In can con
‘so Ill .00 not our III Ill 0010'. no!
WEIGHTS.
mvcnrsrr. ('raor.)
Grain (7}; th of a pennyweight)....
Pennyweight (7,16 th of an ounce)"
Ounce (11.,- th of‘a pound troy)......
Pound troy (5760 grains).............
FRENCH.
0'064798 gramme.
1'555160 gramme.
31‘103191 grammes.
373238296 grammes.
ENGLISH. (nvornnurors)
Dram (57th of an ounce)1............
Ounce (1%, th of a pound)
Pound avoirdupois Hundredweight Quintal, (112}
pounds)
Ten (20 cwt.)
runners.
1'772 gramme.
28349 grammes.
453'558 grammes.
50'80 kilogrammes.
1016'04 kilogrammes.
mrenrsu.
15'4325 grains troy.
0'6430 pennyweight.
15432-5 grains troy.
2-6793 pounds troy.
2'2046 pounds avoirdupois.
FRENCH.
col. Ill 00' DP. 0.0 00. coo-Ill Ian on It.
Icvllvocvoll II‘... I" col 000{
In round numbers, for convenient calculation, where
minute accuracy is not necessary, it may be well to
bear in mind, that 1 cwt. is almost equal to 50 kilo-
grammes, and consequently 1 ton to about 1,000
kilogrammes.
WELD, a yellow dye stuff, consisting of the dried
leaves and stem of the Resedu luleolu, an annual her-
baceous plant indigenous in Britain and other parts
of Europe. It exists in the cultivated and wild state,
and is gathered when in seed, its dyeing power being
then greatest. The cultivated plant yields most dye.
The decoctionhas a slight acid reaction, and a greenish
colour, which is deepened by alkalis, and made paler
3 n 2
980
W ELDlNG—e- WELLS.
by dilute acids. It forms a yellow lake with alum,
acetate of lead, or protochloride of tin. A white sub-
stance called Zateoline may be obtained by treating the
decoction with hydrated oxide of lead, decomposing
the resulting compound with sulphuretted hydrogen,
and evaporating the filtered liquor. Luteoline is a
white volatile substance, subliming into yellow and
white needles. .Z'ntteole’ine is formed by the action of
alkalies upon luteoline; it is a yellow crystalized
sublimate, sparingly soluble in water, but freely so
in alcohol and ether.
Saw-wort (Serntnln tinctorz'a), and dgers’ hroorn
(Genistn tinctorin), contain each a colouring prin—
ciple similar to that of weld. See Lacxnn.
WELDING is the art of joining together two
pieces of iron by means of heat. In technical lan-
guage, this is called shutting together, or shutting
ago. The operation bears some resemblance to that
method of forming joints described under CARPEN-
TRY, called scar/ing; but in smith’s work the joints,
also called scar/‘s, do not, from the adhesive nature of
the iron when raised to the proper temperature, require
anything answering to the glue, bolts, straps, and
pins, used for joining wooden beams and girders. In
joining two cylindrical ends, the scarfs required for
the shut are made by upsetting or thickening the iron
by hammering its extremities; it is then rudely ta-
pered off to the form of a flight of steps, and the sides
are slightly bevelled or pointed. The two extremities
are next raised to the welding heat, when a little
sand is sprinkled upon each; this fuses and spreads
into a kind of varnish, which defends the hot metal
from the oxidizing influence of the air. The proper
heat has been attained when the iron begins to burn
away with vivid sparks. Two men then take each
one piece, strike them forcibly across the anvil to
detach any loose cinders, then place them in their
proper positions for the joint, when they are united
by two or three blows of the fireman’s hammer; and
his assistant completes and finishes off the work
with a sledge hammer. The end of the rod is next
jumped upon the anvil and struck end-ways, to prove
the soundness of the joint, or to enlarge the part,
should it have become reduced in size by the
welding.
Examples of welding are given under FoReING—
CnrLnnr—InoN—GuN-Bannnn
WELLS. The method of procuring water from
wells was practised at an early period in man’s his-
tory. The importance attached to wells of water is
illustrated in numerous passages in the sacred re—
cord; but the wells of Syria seem to have consisted
of mere excavations in the sides of rocks and hills
where springs of water existed, and the water rose so
near to the surface as to be in reach of a bucket
attached to a short rope. In ancient Greece, this
method was also adopted, and it was usual to finish
the orifice of the well with a cylindrical curb of
marble. The operation of boring for water is at
least 4,000 years old, and was extensively prac-
tised in Syria, Egypt, and other countries. The
method of boring for water is described under

BORING. The hydrostatic conditions of springs,
wells, and fountains, are noticed under Anrnsrxn
WnLLs.
The art of well-making in Modern Europe was,
previous to the comparatively recent introduction of
Artesian wells, confined to the sinking of circular
shafts (as described under TUNNEL) until land-springs
were met with. The operation of steining or lining
the excavation with brick or stone is not required
when the shaft is sunk through chalk or rock. In
some cases, where a loose soil overlies the chalk,
steining is required until the hard rock is met with.
It was formerly the practice in this kind of brick-
work to use wedges of slate, bond timber, and com-
mon mortar; but the timber was liable to decay, and
the lime of the mortar (unless hydraulic mortar were
used) was liable to dissolve out, even supposing it
would set quickly, which was not the case, and render
the water of the well hard. The use of Roman and
other descriptions of cement has of late years greatly
improved the operation of steining. I’uddling behind
the brickwork in passing through loose wet sand or
loam is also superseded by the use of concrete. In
passing through land-springs the brickwork must be
executed in cement, or cylinders of iron must even be
used instead of brickwork. In short, the various
precautions required for sinking shafts as described
under COAL—MINE, MINING—Roars AND RAIL-
noans, and TUNNEL, may be required in sinking the
shaft of a well.
The bricks used in steining should be hard, square,
and well burnt; malm-paviors or the best stocks
should be used. The bricks are usually built in under
the executed part of the work, as described in TUN—
NEL, Fig. 2185. The steining is commonly executed
partly in dry and partly in cemented work, the latter
forming rings at intervals which vary with the nature
of the ground; from 5 to 12 feet in London clay;
but in some cases a considerable distance requires to
be laid entirely in cement. The rings are commonly
3 courses thick and about 9 inches in height. The
bricks are laid flat, as in Figs. 2359, 2360, the courses


Fig. 2359.
Fig. 2360.
alternately breaking joint; wedges or cement being
introduced in the open spaces between the bricks.
The thickness of the steining is regulated by the
diameter of the well and the nature of the soil. In
some cases 9-inch work is used, laid dry and radiating,
as in Fig. 2360, or in
separate ‘iii-inch rings,
as in Fig. 2361. This of course is not so strong as four-and-a-
half work, laid in ce- ‘
ment. In excavating

Wl-IALEBONE.
981
from one ring to another, the hole is dug as far as
the nature of the ground will allow, and a line is
plumbed from the brickwork above, in order to deter-
mine the position of the face of the brickwork in the
lower rim. In sandy soils, with a shallow well, the
plan of working on a curb, described under TUNNEL,
Fig. 2185, may be adopted, in which case the steining
should be set entirely in cement.
As the work proceeds, the well~diggers become in-
eonvenienced from the fouling of theair. Hence the
excavation should be ventilated, for which purpose
bellows or a fan-blast may be used to propel the air
down zinc-pipes to the workmen. A plentiful supply
of fresh air will enable them to perform their work
with greater ease and expedition.1
WHALEBONE. This well-known substance is
an albuminous tissue closely resembling hair and
bristles in its chemical and vital properties and mode
of development. It has nothing in it of the nature
of bone, and hence the more appropriate term taken,
has been proposed for it. The whales or cetaceans,
which produce it, are of a more timid nature than the
great sperm whale; they have no teeth, but instead
thereof, horny plates ending in a fringe of bristles.
The largest of these plates are of an unequal triangu-
lar form, and are “arranged in a single longitudinal
series on each side of the upper jaw, situated tolera—
bly close to each other, depending vertically from the
jaw with their flat surfaces looking backwards and
forwards, and their unattached margins outwards and
inwards, the direction of their interspaces being nearly
transverse to the axis of the skull. The smaller sub-
sidiary plates are arranged in oblique series, internal
to the marginal ones. The base of each plate is hol-
low, and is fixed upon a pulp developed from a vas-
cular gum which is attached to a broad and shallow
depression, occupying the whole of the palatal surface
of the maxillary and of the anterior part of the pala-
tine bones. The base of each marginal plate is the
smallest of the three sides of the triangle: it is un-
equally imbedded in a compact subelastic substance,
which is so much deeper on the outer than it is on
the inner side, as, in the new-born whale, to include
more than one-half of the outer margin of the baleen-
plate. The form of the baleen-clad roof of the mouth
is that of a transverse arch or vault, against which the
eonvex-dorsum of the thick and large tongue is ap-
plied when closed. Each plate sends oil’ from its inner
and oblique margin, the fringe of moderately stiff but
flexible hairs which project into the mouth. The
bases of the baleen-plates do not stand apart from one
another, but the anterior and posterior walls of the
pulp-fissure are respectively confluent with the conti-
guous divisions of the bases of the adjoining plates at
their thin and extreme margins, which by this con-
fluence close the basal end of the interspace of the
baleen-plates, which interspace is occupied more than
half-way down the plate by the cementing substance
or gum. Thin layers of horn, in like manner, connect
the contiguous plates, and may be traced extending
in parallel curves with the basal connecting layer
across the cementing substance. The baleen-pulp is
situated in a cavity at the base of a plate like the
pulp of a tooth; whilst the external cementing mate~
rial maintains, both with respect to this pulp and the
portion of the baleen-plate which it develops, the
same relations as the dental capsule bears to the tooth.
The baleen-plates are smallest at the two extremities
of the series; in the southern whale (.Balama Austra—
Zz's), they rapidly increase in length to the 30th, then
very gradually increase in length to about the lltOth ;
from this they as gradually diminish to the 160th
plate, and thence rapidly slope away to the same
small size as that with which the series commenced.
Besides the external plates just described, there are
developed from the inner part of the palatal gum in
the Balmza Australia, a series of smaller fringed pro-
cesses progressively decreasing in size as they recede
from the large external plates ; the small plates clothe
the middle region of the palate with a finer kind of
hair, against which the surface of the tongue more
immediately rests; they are also arranged in longitu-
dinal series, which however are not parallel with the
external one, but pass from the inner margin of that
series in oblique lines inwards and backwards. In the
great northern whale (Beltane mysticetus), the baleen
plates, which succeed the large ones of the outer row,
are more numerous, and are relatively longer and
larger, than in the Brahma Australia. The marginal
plates are about 200 in number on each side; the
largest are from 10 to M feet, very rarely 15 feet in
length, and about a foot in breadth at their base. Each
plate of the baleen consists of a central coarse fibrous
substance, and an exterior compact fibrous layer; but
this reaches to a certain extent only, beyond which
the central part projects in the form of the f ringe of
bristles. The chemical basis of baleen, according to
Brande, is albumen hardened by a small proportion of
phosphate of lime. The final purpose of this singular
armature of the upper jaw of the great whales is to
secure the capture and retention of the small floating
mollusks and crustaceans, which serve principally as
their food. When the capacious mouth is opened, the
water rushes in, and is strained through the fringed
surface of the roof and sides, whilst the small animals
are retained, bruised against the stifli-bristled margins
of the plates, and swallowed.“ ~
Baleen or whal-ebone possesses some valuable pro-
perties, which cause it to be applied to a variety of
useful purposes. It is prepared for use by being
boiled in water for several hours, by which it becomes
soft enough to be cut up while hot into the required
lengths. By means of a compound guarded knife, it
is cut into fibres as a substitute for bristles in com-
mon brushes. Whalebone that has been boiled is
harder and of a deeper colour than before; jet-black
whalebone is the result of dyeing. The chief con-
sumption of whalebone is for the stretchers to

(1) In Mr. Weale’s Rudimentary Series will be found an interest-
ing treatise on Well-digging, Boring, 8zc., by Mr. Swindell, 2d
edition, revised by Mr. Burnell. 1851.

(2) Professor Owen. Lecture at the Society of Arts. “ 0n the
Raw ‘Materials from the Animal Kingdom displayed in the Great
Exhibition.”
982
WHALE OIL-L—WHEAT.
umbrellas and parasols. It was formerly used largely length; it was formerly of much larger size, and it is
in imparting stiffness to women’s stays; the consump-
tion for this purpose has considerably declined of late
years, owing to a conviction that the artificial shape
produced by tight lacing is not only injurious to
health and personal comfort, but that the natural
shape is more graceful to the eye. Whips are also
made of plaited whalebone, both black and white.
Ladies’ bonnets and artificial flowers have been made
of shavings of white whalebone, its texture being well
adapted to the purpose; very bright and durable
colours can also be imparted to it by the usual pro-
cesses of dyeing. Solid pieces of whalebone of mixed
shades are sometimes twisted together for walking-
sticks; but this substance does not admit of being
soldered like tortoise—shell. Whalebone is used for
covering pocket-telescopes, and such covers are neat
and durable. In such an application narrow pieces
of whalebone are grooved or made into ribs by draw-
ing them through an aperture in a steel plate, after
which they are wound round the tube, and “tucked
under” the rings at the extremities. Broad flat
strips of party-coloured whalebone (the light portions
of which have been dyed green, the darker portions
rejecting the dye) are also used; they are secured by
narrow black bands which overlap the two edges, the
ends being also furnished with bands.
Whalebone is polished by first scraping it with
steel scrapers or pieces of window-glass, next rubbing
it with emery—paper, and then with woollen cloth
supplied with tripoli or rotten—stone.
WHALE OIL. The Greenland whale (Baleeaa
mystz'oelas) is valued for the sake of its oil. Its pursuit
forms an important branch of industry as well as a
nursery for British seamen. It was formerly found
on the east shores of Greenland, but of late years in
Davis’s Straits and the interior of Baifin’s Bay. The
ships engaged in this trade are furnished chiefly by
the ports of North Britain; Hull, Peterhe'ad, Dundee,
and Aberdeen, being the chief. The ships usually
quit the Shetland Isles in April, and reach their
locality in May or June. As soon as a “fish” is
seen the boats are sent out in pursuit, and when near
enough for the purpose, it is struck with a harpoon
or barbed spear, to which a long line is attached.
The whale dives and swims rapidly under water, his
direction being indicated by the running out of the
line. The boats follow in this direction, waiting until
the animal comes up to the surface to breathe, when
other harpoons are darted into its body, and the crea-
ture again dives. In this way its strength becomes
exhausted, and being at length dispatched with long
steel lances, it is towed alongside the ship, made fast
with tackles, and the superficial blubber fleasetl off by
men, who walk on the carcase with spiked shoes.
When both sides of the animal have been stripped,
the whalebone got out, and the jaw-bones, which are
full of oil, hoisted on the deck to drain, the carease or
lereag is cut adrift. A large whale will often yield
above 20 tons of rendered oil, which, with the other
products, may be worth nearly 1,000l.
The Greenland whale rarely exceeds 70 feet in

probable, from the eager pursuit of this animal, that
it seldom attains the adult size in the northern seas.
The head is about one~third of the whole length.
Common whale, or train oil, has a specific gravity
of 0927 at 68°. At 32° it deposits stearine; it is
readily saponified, forming a brown soluble soap.
The CaeIzalozfs, or sperm whales, are remarkable for
their enormous heads, which are square, and appa-
rently out OK in front. The head is hollowed into large
caverns containing a peculiar oil, which on cooling
becomes hard, and when refined forms spermaceti.
The animal is pursued chiefly for this substance, for
it produces no whalebone and very little blubber. It
also furnishes ambergrz's. The Phyceter, or sperm-
whale, is of great size and strength, and becomes
furious when wounded. It is pursued both in the
northern and southern seas, and the pursuit is accom-
panied with great danger.
The oil of the spermaceti—whale is purer and burns
more brilliantly in lamps than common whale-oil
Its specific gravity is about 0927, and it saponiiies
readily. Spermaceti may be purified by pressure,
and by boiling in a weak solution of potash: it is
next washed, melted in boiling water, and cast into
blocks: when the exterior has become solid,.the liquid
interior portion is allowed toiflow outpand the inte—
rior of the block then exhibits a beautiful lamellar
crystalline texture. Spermaceti is greasy to the touch:
its sp. gr. is 094:; it fuses at 112°. It is very spa—
ringly soluble in hot alcohol: it dissolves in the hot
oils. By trituration with alcohol, a little oily matter
is extracted, and the residuary pure spermaceti has
been named. eelz'ae. Its formula is CzosHzosOm. It
does not saponify readily with hydrated alkalies, but
when digested with a solution of caustic potash, in
twice its weight of water, for several days, at a tem-
perature between 120° and 190°, it becomes con-
verted into a peculiar soap containing margarate and
oleate of potash, together with an unsaponified fat
termed, by Chevreul, elfial, C32H33O,I:IO. Ethal is
a neutral crystallizable fat, of which the melting point
is nearly the same as that of spermaceti, but it is
much more soluble in alcohol; it can also be sublimed
without decomposition. According to one view, sper—
maceti contains neither oleic nor margaric acid, but
the product of its saponification is said to be eflzalz'e
acid; hence spermaceti has been regarded as an etlza—
lale 0]” el/zal. Ethalic acid resembles margaric acid
in many respects. Spermaceti yields by oxidation
with nitric acid a large quantity of saeeem'e aez'al.
See AMBER. '
WHEAT. The composition of wheat is given
under BREAD and STARCH. The former article also
contains a description of the various processes-for
preparing flour by the common method. The results
of the Great Exhibition have furnished various parti-
culars respecting improved methods of cultivating
wheat, and grinding it into flour, which we now pro-
ceed briefly to enumerate. Professor Lindley, in his
Lecture delivered to the Society of Arts on the
Vegetable Products of that great display, makes
WHEAT.
983
‘ here.
certain statements respecting wheat which we here
abridge.
‘Wheat will probably be regarded by many as all-
important in the vegetable world, and there are some
circumstances connected with it which particularly
deserve to be brought under public consideration,
and especially one which, although the corn-factors in
Mark Lane are familiar with it, is by no means a
matter of universal notoriety—viz. the high character
and excellence of the wheat of our South Australian
colonies. A sample of wheat from Adelaide, pre-
sented probably the most beautiful specimen of
corn that has ever been brought to _market in any
country. It is a white wheat, in which every grain
appears to be like every other grain—plump, clear-
skinned, dry, and heavy, weighing, what may seem
incredible to those who are only accustomed to com-
mon wheat, 70lbs. a bushel. And it appears that
Adelaide is capable of yielding vast quantities of corn
of this description, which takes the lead in the mar-
kets of this country over all other white wheats.
It is very true that, from Spain there has come a
similar kind of wheat, of great excellence also, as is
seen by a beautiful sample from Castile, the weight
of which is unknown, and not easy to estimate, be—
cause it is not a clean sample. This is certainly of
great excellence also; but, independently of its being
the produce of a foreign country, it is almost inacces-
sible to us, and therefore a matter of curiosity more
than of practical value, because, owing to the difliculty
of transport, it cannot at present come into the markets
of this kingdom. If it could, considering that it sells
in Old Oastile at 24s. a quarter, it is not easy to say
what might be the effect upon the English market of
the introduction of any large quantity of it. We find
moreover that similar qualities of wheat, growing in
the same rich country of Spain, are vendible at much
lower rates. With respect to the wheat of South
Australia, it has been supposed that all we have to do
in this country, in order to obtain on our English
farms wheat of the same quality as this magnificent
Australian corn, is to procure the seed and sew it
here. There cannot be a greater mistake. The wheat
of Australia is no peculiar kind of wheat; it has no
peculiar constitutional characteristics by which it may
be in any way distinguished from wheat cultivated
in ‘this country; it is not essentially different from.
the fine wheat which Prince Albert sent to the Exhi-
bition, or from others which we grow or sell. Its
quality is owing to local conditions—that is to say, to
the peculiar temperature, the brilliant light, the soil,
and those other circumstances which characterise the
climate of South Australia inwhich it is produced;
and, therefore, there would be no advantage gained by
introducing this wheat for the purpose of sewing it
Its value consists in what it is in South Aus-
tralia, not in what it would become in England“ In
reality, the experiment of growing such corn has been
tried by Dr. Lindley, and the result was a very infe-
rior description of corn, by no means so good as the
kinds generally cultivated with us, the crop therefrom
being ugly, coarsergand ‘bearded. It appears, there-

fore, that wheat may be affected by climate, inde-
pendently of its constitutional peculiarities; but it
does not follow that wheat is not subject to consti—
tutional peculiarities like other plants. There are
some kinds of wheat which, do what you may with
them, will retain a certain quality, varying but slightly
with the circumstances under which they are pro-
duced; as, for example, is proved by some samples,
especially of Revz'a‘t wheat, of a very fine descrip-
tion, exhibited in the building by Mr. Payne, and
which is greatly superior to the ordinary kinds of
Revitt that appear at market. This clearly shows
that Revitt wheat of a certain kind and quality is
better than Itevitt wheat of a different kind, both being
produced in this country; so that, circumstances
being equal, we have a different result, owing to some
constitutional peculiarity of race.
But there is one question of the highest interest,
which has been ‘more distinctly brought out in the
Great Exhibition than it has ever been before. We
all know the effect of hybridizing, or crossing the races
of animals; and we also know that, within certain
limits, this may be done in the vegetable kingdom.
We are all aware that our gardeners are skilful in
preparing, by such means, those different varieties of
beautiful flowers and admirable fruits'wnich have be-
come common in all the more civilized parts of Eu—
rope, but no one has paid much attention to the ‘point
as regards cereal crops. Yet it is tobe supposed,
that if you can double the size of a turnip, or if - you
can double the size of a rose, or produce a hardy race
of any kind from one that is tender, or the reverse, in
the case of ordinary plants, you should be able to
produce the same effect when operating on cereal
crops. It so happens, however, that the experiment
has not been tried, except on the most limited scale,
and to what extent it may be carried has been more
brought out in this Exhibition than it ever was be-
fore. In the last treatise on this subject by Dr.
Gaertner, a German writer, who has collected all the
information it was possible to procure relating to the
production of hybrids in the vegetable kingdom, the
author declares that, as to experiments on cereal
plants, they can hardly be said to have had any ex-
istence. The Exhibition has nevertheless shown us
that they have been made, and proves distinctly that
you may operate upon the constitutional peculiarities
of wheat, just as you may upon the peculiarities in
any other plant. For instance, Mr. Baynbird of
Laverstolce, who obtained in 1848 a gold medal from
the Highland Society for experiments of the kind,
sent to the Exhibition a box, which contained a
bunch of .Hopetoma wheat, a white variety, and a bunch
of P5120198‘ Thickset'w/wat, which is red. The latter is
coarse and short-strawed, and liable to mildew, but
very productive. Mr. Raynbird desired to know what
would be the result of crossing it with the Hope—
toun wheat, and the‘ result was shown in the form of
four hybrids, obtained from these varieties. The new
races thus obtained are intermediate between the two
parents,--the ears are shorter than in the Hopetoun,
and longer than in the Thiekset wheat ; in short, there
9841
WHEAT.
is an intermediate condition plainly perceptible in
them throughout. And it appears from the state-
ment of Mr. ltaynbird that these hybrid wheats,
which are now cultivated in this country, have suc-
ceeded to a satisfactory extent, yielding forty bushels
an acre. But in this instance, as in some others, the
essential part of the question is not the number of
bushels produced per acre, but to show that you may
affect the quality of cereal crops, as you may affect
animals and other plants. Mr. Maund, an intelligent
gentleman, residing at Bromsgrove in Warwickshire,
has done much more than Mr. Raynbird, for he has
obtained a greater variety of results. Mr. Maund has
been occupied for some years past in the endeavour
to ascertain whether something like an important
result cannot be produced upon wheat by ranting, and
he exhibited the specimens before us in evidence of
what may be done. You will observe that sometimes
his hybrids are apparently very good, and sometimes
worse .than the parents, as we know is always the
case. When you hybridize one plant with another, you
cannot ascertain beforehand with certainty what the
exact result will be, but you will take the chance of
it, knowing very well that out of a number of plants
thus obtained, some will be of an improved quality.
In the present specimen, in each instance the male
parent is on the left hand, the female on the right,
and the third specimen shows the result of combining
the two kinds: a better illustration could not be de-
sired. Here is a hybrid considerably larger than the
parents, and in the next instance one considerably
shorter and stouter. In another example, you see a
coarse variety gained between two apparently fine
varieties—that is, perhaps, a case of deterioration.
In another example, you have a vigorous wheat on the
left, and a feeble one on the right, while one much
more vigorous than either is the result. On the other
hand, we have some anomalous cases, in which the
effect of hybridizing has been to impair quality. This
is a very important case, well made out, because
the moment you show that by mixing corn, as you
mix other things, you obtain corresponding results,
there is no reason to doubt that an ingenious person,
occupying himself with such matters, will arrive at
the same improvements in regard to varieties of corn
as have ah'eady been obtained in the animal kingdom,
and in those parts of the vegetable kingdom which
have been so dealt with.
We now proceed to state some of the improved
processes of milling or meeting wheat; and having
l'ately inspected the machinery and arrangements of a
highly intelligent and enterprising miller, Mr. Feltham,
of Crowborough in Sussex, we will briefly notice
them, and also the arrangements of the City flouf
mills, which we have recently visited. The varieties
of flour used in London consist chiefly of the follow-
ing kinds :—-1. Best flonr, known as .Pnstrg Whites;
2. Whites; 3. Households ,- 41. No. 2, or Seconds ; 5._
Thirds; 6. ,Fine llfiddlings. There is also a pecu—
liar kind of flour used for dusting, in order to give
a_ fine colour and texture to .the outside of loaves.
Any one of the above varieties of flour has dis-
.cleaning apparatus.

tinctive properties of its own which are well known
in the trade, and is produced by the admixture of
several varieties of wheat, so proportioned as to
secure the desired qualities of whiteness, strength, and
jerrnentahititg. Thus, a wheat rich in gluten may be
mingled with one which contains abundance of starch;
a red wheat may be combined with one that is white;
or a wheat that is moist with one that is dry. The art
of mealing depends for its success upon the judicious
mixtures of wheat, and upon such an arrangement
of machinery that the whole of the flour which the
wheat is capable of producing may be obtained from a
single grinding. From the mixing bin the wheat is
passed through a blowing apparatus, the object of
which is to separate dust and light particles; it is
then passed through a smut-machine, consisting of
iron heaters, enclosed within a skeleton cylindrical
frame covered with wire, (that of a square section
being preferable,) with spaces sufficiently wide to
allow the abraded particles to fall through. The
heaters revolve from 400 to 500 times per minute,
and by their action against the wires, scrub the
wheat, and cause the particles of dust, &c. to fall
through the wire covering to the outside. The wheat
is next passed into a screen, arranged spirally on a
horizontal axis, so as to expose a length of 30 yards.
The revolutions of this screen further separate dust
and small seeds. Finally, after leaving the screw, it
is exposed to a current of air from a fan, which com-
pletes the removal of chaff, dirt, or shell of smut-ball.
That this elaborate process of cleaning is not super-
fluous, is evident from the large accumulation of dust,
dirt, and offensive matter, in and about each piece of
The result is that the flour is
improved in whiteness and wholesomeness, and the
reputation of the mill maintained for high qualities of
flour. The various cleaning machines are so arranged
that the wheat is passed from one to the other without
loss of time, and it proceeds from the last blower to
a hopper which supplies the mill-stones. The ordi-
nary method of grinding is described under Bnnsn.
Since that article was written, improved methods have
been introduced, the objects of which are to prevent
that loss of fine flour, arising from the centrifugal
force of the runner, whereby the air of the mill is
charged with fine particles, and the health of the
millers injured. In Swayne and Bovill’s improved
method of grinding corn, the stones are completely
boxed in, and a blast of air is so directed upon the
grinding surfaces that the stones are kept cool, and
the flour is removed as fast as it is formed. These
gentlemen state truly, that in mills of common con-
struction the flour is of necessity re-ground, or rather
mashed up with the unreduced particles, until by the
action of the running stone it is slowly discharged
at the outer edge, considerable heat and colour having
been thus imparted to it, and its strength materially
impaired. They go on to state, that by their new
process the flour is delivered from between the stones,
at the instant of its production, in a cool state, leaving
the surface of the stones free for the purpose of
grinding only. By this process about 8 bushels of
WHEAT.
.985
wheat can be ground per hour, at bushels being the
limit by the ordinary method. About 80 per cent.
of fine flour is obtained, cool and lit for dressing as
fast as it is ground, thus saving labour, space in vthe
mill, and avoiding waste. The waste need not exceed
15 per cent. or 6 lbs. to the quarter, since all the stz've
is caught and conveyed into a chamber, where it is
collected and mixed in with the flour. By cooling
the flour as fast as it is produced, it is not discoloured,
so that a larger proportion of red wheat may be used
in the mixing-bin, and as good a colour be obtained,
as if the wheat had cost three or four shillings per
quarter more. Another advantage of cooling is, that
the meal can be dressed through silk machines (to be
described) ; and thus a quality of flour can be obtained
equal to that of France, where the superior ~dryness
of climate allows of .a more perfect dressing. It is
stated that the bakers can make from 4.1 to 6 loaves
more per sack from this flour than from that prepared
by the ordinary process. By this plan the wheat does
not require to be dried before grinding.
The arrangement of the apparatus will be under-
stood by reference to Fig. 2362, which represents a
- é )
‘ x’, was" I
/


pr’




D
:31
r...’
,
1
vertical section of a pair of ordinary mill-stones,1 with
the patent apparatus attached. A A are the stones as
usually employed, with furrows cut it-inch deep, and
the lower edge of the eye of the runner bevilled to
freely admit the air-blast, as shown at a. B is the
driving spindle, on which the cup 0 is attached, to
receive and distribute the grain from the telescope
feed-pipe, I), which is regulated in the ordinary manner
with the lever and rod, E n. The centre of the stone
case is closed by a cast-iron plate, r, having apertures
for receiving the blast-pipe, e, and feeding-tube, 1), a
leather ring or washer being fixed at b, forming an air-
tight joint through which the feeding-tube works. G
is the air-pipe from an ordinary fan or other blowing-
machine. H is a cast-iron grooved ring, attached to
the top of the running-stone around the eye. J is a
circular leather inserted into the groove of the cast~
“5%
\4
a





Fig. 2362.
iron ring, and secured to the mill-stone case under,
the plate F, the object of which is to prevent the
current of air or any grain passing otherwise than

(1) Messrs. Bovill and Swayne have introduced a new de-
scription of Burr stone from Belgium, which is said to be equal
to the best French mill stones. " -

through the centre of the running-stone. The blast
of air, ‘blowing from the centre outwards between the
grinding surfaces, ‘discharges in its current, in a pure
state, every particle of meal as soon as it is produced
from the grains. In this process the furrows of the
stones must be considerably enlarged. K is a waste
air-pipe, 12 inches square and 3 feet high, having an
elbow, 0, on the top, the opening being in the contrary
direction to the run of the stone. The escape-pipe
for the air is placed over an opening of the same size,
cut on the top of the stone case, which admits of the
free egress of the wind blown through the stones
without waste of meal. Lisa meal-spout, 12 inches
square, and not contracted ‘at the bottom, by the
arrangement of which and the waste-pipe, K, any stive
or waste of meal is entirely avoided. For this purpose
the blast of air,.having served its purpose between the
mill-stones, is conveyed into a room or closet lined
with woollen cloth of peculiar texture, through which
the air filters, leaving behind the fine particles of
flour which would otherwise escape into the mill.
An exhausting pipe containing a fan is connected
with this closet, for the purpose of facilitating the
escape of air. The only objection which we have
heard to this otherwise excellent arrangement is, that
the cloth soon becomes so choked with flour in a
moist state as to arrest its action in filtering ~the air,
and so to require frequent renewals of the cloth.
Another arrangement, known as the Conical Flour
Mill, has of late years excited considerable attention,
and led to much discussion. The principle of this
invention may be given in the words of Mr. Boy-
man’s statement, contained in the prospectus issued
by the .“ Conical Flour Mill Company,” which we
here insert, with the omission of certain superfluous
observations. The def ects of the old system are thus
stated :——
“ For a pair of stones 11-f'eet diameter, an engine
of 4-horse power, actual, is required. The lower
stone is fixed; the upper one weighing 111- cwt. re-
vol-ves, the grinding surface working at a mean velo-
city of 15'18ét feet per second, when the stone makes
120 revolutions per minute, the average number for
this power. Through a hole of 10 inches diameter,
called the eye, in the middle of this revolving stone,
the wheat enters, and is drawn between the stones
and ground, the stones being slightly chiselled out
in lines, called dressing, to produce the grinding
surfaces.
“So heavy a weight, flying round at this high
velocity, soon crushes the wheat, and reduces the con-
tents to flour, when it ought immediately to escape,
but cannot; so large is the area of the stones, so
great is the pressure of the top stone, and so clogged
up do they become by the sticky meal having to travel
so far. Thus, from the instant that the meal is re-
tained beyond the time required to grind it, dete-
rioration commences, and power begins to be use-
lessly consumed in getting it out of the way, which it‘
can only do very slowly; for every particle must
describe a volute, with minute, but gradually enlarg-
~‘ ing ‘circles, until it ‘gets to the edge or skirt of the
986
WHEAT.
stone, and is discharged. And were the coefficient
of friction resistance to the centrifugal velocity ascer-
tained, the actual distance to which the meal is sub-
ject to this grinding action could be determined.
But it must be very great, circling as it does round a
stone of 41 feet diameter, since the friction resistance
of an adhesive substance like meal to the centrifugal
action is so considerable. It is thus easy to see that
some portion of the bread-making properties of the
flour are destroyed by so much unnecessary tritura-
tion, and that much power is consumed in getting
rid of a material so retarding as meal, beyond that
required merely to grind the wheat.
“The ConIoAL MILL obviates these defects to as
great an extent as is practicable, because it is the
nearest approach to natural mechanics. We can see
with what admirable economy of power the jaws of
the horse are contrived to grind his corn. The heavy,
head-bearing, upper jaw is fixed ; the lower one moves,
and being of little weight, requires but little power
to move it. It is also an upward pressure, so that no
weight rests upon the corn, as in the present erro-
neous system. Its pressure, therefore, is exactly
proportioned to the work it has to do, and no more;
whilst the lower grinders, with their serrated edges,
may be likened to little mill-stones of small surface,
which, with a semi-rotary motion, reduce the corn to
meal. Designedly or not, the Conical Mill is on pre-
cisely the same principles throughout. The upper
stone is fixed, the lower one revolves, and instead of
being 14: cwt., like the upper revolving stone of the
present mills, is only 1 cwt- 2 qrs. Thus the upward
pressure is as nicely proportioned as the horse’s jaw,
sulficient only to open, not to crush, the corn. It is,
too, of small surface, like the grinders of the horse,
and set at an angle not many degrees removed from
that of the horse’s jaws.
“ These natural principles of grinding, Mr. Westrup
has very ingeniously carried out. Instead of having
one small conical surface, whereby some of the meal
would be re—ground, and the stones become clogged,
though not to the same extent as on the old prin-
ciple, he divides even this smaller surface into two,
by having two pairs of conical stones on the same
shaft, the lower pair about 2 feet 8 inches beneath the
upper, so that each surface is only as 1 to 3'34: of the
old. And to prevent any portion being re-ground, the
first object to be avoided in good milling, there are
vertical brushes fixed to the shaft, between the two
pairs of stones, extending to a radius of 14; or 15
inches, and nearly touching a fine-meshed cylinder
that surrounds the whole mill. No sooner, then, is the
fine fipur liberated from the upper stones, than it is
sent through the cylinder by these revolving brushes,
whilst all that will not go through has not been suffi—
ciently ground, and so passes down into the second
pair of stones, which complete the process.”
It is asserted that this is the true principle of
grinding; “ the means of getting what it has been
the great object of the best millers to get—as much
of the very best and whitest flour possible at the first
grinding, and to get it as soon as possible; that is,

the moment the wheat has been opened and the farina
liberated, which is done soon after the wheat enters
the eye. But, as we have seen, this object never can
be accomplished whilst the flour has to travel round
and round a d-feet stone. Every miller, then, will see
what a superior flour must be obtained from a stone
whose grinding surface is only 3'5986 feet, and which
delivers its flour at a mean velocity of 2183323 feet
per second, as compared to that which has to pass
over a grinding surface of 12021 feet, and which is
only delivered at a mean velocity of 151841 feet per
second. The smallest possible surface, the quickest
possible delivery consistent with coolness, and the
greatest possible quantity, ground at the first casting,
and with the smallest power, constitute the great prin-
ciples of milling, and here they are all combined.
“ It is gratifying to find that all the results of the
French practice are now reached in this country, so
far as regards the quality of the flour obtained from
the first casting or grinding; whilst it is greatly sur-
passed as regards the quantity ground by a given
power in a given time, and also in the money value
of the total produce from a given quantity of wheat,
the first cost of the wheat being the same. Thus the
Conical Mill will do all it is possible for the best
French mill to do, and a great deal the best French
mill cannot do. It will give quantity as well as qua-
lity. The French millwill only give quality. The
French miller takes care to give his mills only the
exact quantity they can grind, that the first opera-
tion may be well done; and this quantity is about
one-half less than even the common English mills, of
the same sized stones, grind in the same time; and
only by this slow process can the French millers get
that fine white flour, so pleasing to the eye in the
best Paris bread, called ‘ Farina ale Graaaa'.’ But
this tedious grinding would not do in England, where
time, the measure of labour, is money. It will not do
for a people who, of all the peopled earth, know best
how to do the most work in the least time, and who
live, for all practical purposes, measured by the useful
work done, twice as long as any other race. And
what they do themselves they make their machines
do. With us every invention is a mere pounds, shil—
lings, and pence affair. What will it do? and what
does it cost in doing iti> So that quantity is as es-
sential as quality. Thus the inventor of the Conical.
Mill does precisely what the French miller does, only
by a better, because more time-saving, economical
system. As a practical miller, he knew the import-
ance of preventing re-grinding; but, instead of re-
ducing the quantity of wheat to prevent it, he reduces
the surface of the stones, removes all injurious pres—
sure, gives them a different shape, and a higher velo~
city; and thus he gets as good a flour as the French
miller, whilst he grinds three or four times as much
in the same time, and, by the Engineer’s Report,
nearly twice as much as the ordinary English mills.
Such then is the difference between the two systems
of milling, from which it will be seen that we still
preserve our twenty years’ advance of our neighbours
in this art, as we beliewve we do in most of the great
WHEAT.
987
subs-tantialities of life that make‘ up the solid greatness
and prosperity of a nation. 7 - I -
“As regards the ability to grind nearly double the
quantity of wheat with the same power, the solution
will be found in the area of each grinding conical sur-
face being as only I to 3'34 of the horizontal stone, a
reduction that can only be obtained by the peculiar
form. of the stones. The result of an area so much
smaller is, as before alluded to, a veryremarkable
savingin power, arising from the great decrease of the
resistance of so adhesive a substance as meal over so
large an area as the old stone, between such rough
and close surfaces, and beneath so heavy a pressure. .
Were the co-efiicients of this resistance known, a
theoretical investigation might be given of the saving
of power; but without such data the mathematician
will best understand how impossible it is to go into
this question.
.“ By analogy, however, some idea may be. formed of
how great this loss must be, from the fact, that the
friction of water through a pipe only six times as long
as it is wide, consumes (011182 + . g
= 11'4: per cent. (Weisbach, volqi. sec. 330 and
331.) And‘were the pipe made of wood, the co-
efficient of resistance would be 1'75 times more than
for smooth metallic pipes, whence we see how much
greater still the loss must be with a sticky material
like meal, and passing through rough stones, where,
. . a . 2
probably, the losslwould be, not merely as 7;, but as g ,
l 2 . .
or 5 because its partlcles do not momentarily
communicate equal pressure in all directions, like
water, and so get out of the way by an equal pressure
throughout its mass 5 for the further the meal has to
be forced between such very rough surfaces, (so
closely pressed too as not to exceed the thickness of
ordinary writing paper,) the more compressed and un-
yielding must it become; therefore the greater must
be the resistance to motion, increasing (doubtless) at
least as the square of the distance, and requiring pro-
portional power to getrid of it. When therefore the
surface passed over is reduced in the proportion of
1 to 3344, it is easy to perceive how great the saving
must be; because the meal being got rid of with the
new ‘stones as soon as it is ground, and the space be-
tween the stones being wider,‘ that power, which, with
the old stones, is consumed in forcing it from between '
the stones, and in re-grinding it, goes to grind the
fresh wheat.”v - - a
The conical flour-milldoes not appear to have come
into very general use, although it may possess many
advantages over the common arrangement‘ of stones.
One objection urged against its use is the liability of
the lower or running stone to fall away from the
uppcrsstone, when by ‘any diminution of the power,
either by a deficiency in the supply of water or of
steam, there is a consequent diminution of centrifugal
force. In the common arrangement of stones, if the
power he not properly kept up the stone will pitch,
that is, get nearer'to the bed-stone, so that should the
'02‘
engine-man be negligent there‘ is not an absolute loss
‘of profit,‘ that is, the corn may be over ground and-
the quality injured, but the quantity ‘will be rather
increased.
stone fall away from its work, the grain would not be
ground sufficiently fine, and some of the best part of
the wheat would get into the middlings, and this
would require the middlings to be ground over again.
We are also informed that it is diflicult to keep the
conical stones in floor, that is, to dress their surfaces
so that they may be always true.
The prnanc' principle of grinding wheat, referred to
above, is thus noticed in the Jury Report of the Great
Exhibition, Class II. :—
“ The magnificent gruaux wheat-flour of M.
D’Arblay, jun. has occupied much of the attention
of’the Jury, not only as the best sample of European
flour, but from the exhibitor being the inventor
of the gruaux principle in grind-ing, whereby'a great
saving of the finest and most nutritive ‘portion of the
flour is effected, and any wheat-flour made to contain
more or less gluten in proportion to starch. Hard
w-heats of all kinds, especially Sicilian, Russian and
Sardininn, from the large per centage of gluten they
contain, are the best adapted for this purpose. By
means of D’Arblay’s adjusting process, such grains
are first ground high in the mill; the white middlings '
are then separated by coarse sieves, and re-ground
low in the mill ; ‘finally, the flour is repeatedly passed
through fine silk sieves. This process is evidently
tedious and expensive; but the flour produced is of
the very finest description, especially for pa’ics, and
other preparations of that description. The average
produce of flour thus obtained is 25 per cent. from
ordinary wheat. Such flour is extensively imported
into this country, for bettering the inferior flours,
especially the Irish. D’Arblay’s household/lam‘, ob-
tained by the usual grinding process, is also of first-
rate quality. ' A council medal has been awarded to
M. D’Arblay ‘for his gruaux and household flour,
obtained by a novel and economical process, for the
fineness of its quality and utility.’ ”
In the common arrangement of stones the meal
passes down a shoot into va meal-bin. The falling
meal conveys a considerable sensation of warmth to a
hand held in it; and it is necessary to preserve the
meal in sacks for some weeks,‘ in order that it may
cool, as it is technically called, or become fit for
dressing. If the meal is thus treated, the flour made
from it will stand its weight for months, but if dressed
as soon as ground, the flour loses in weight about 4‘ lbs.
per sack, and is also liable to [rent and ca/cc. The
drcssiny mac/iinc [see BREAD, Fig. 226] is a skeleton
cylinder covered with wire, and containing from six
to eight brushes.
from list to 72 meshes to the inch according to
the weather, (the damper the weather, the coarser
the wire.) This machine separates the meal into flour
and middlings. The flour is a finished product; but
the middlings require to be passed through a bolting
mill, whereby three qualities are produced, viz. fine
middlings, coarse‘ middlings, and ‘thirds flour. ' The
In the'conical arrangement, should thev
The wire should vary in fineness‘
988
WHEAT.
first of these is largely employed for sailors’ biscuits,
the second for pig~feeding, &c., the third is sold as
thirds flour. Seconds flour is produced from an in-
ferior wheat. The raj/‘use or qfi'al is passed through
a jumper, consisting of a frame containing wire-
gauze of various degrees of fineness, and is thus sepa-
rated into four descriptions, viz. supevfirze pollm‘d,
jhze Pollard, lam-ac policed, and 67mm.
The most extensive and probably the best appointed
M/Jl
p
' “-
z' s
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of a powerful fan. From this trunk proceeds a smaller
trunk obliquely into the casing of each pair of mill-
stones, and when the blast has served its purpose, it
escapes up another oblique trunk, into a second long
horizontal shaft, in which the air is rarified by means
of a fan. This trunk conveys the air into a chamber,
lined with woollen cloth, as already noticed.
The wheat is hoisted to the top floor, where, after
undergoing certain cleaning operations, it is let down
to the stones. The meal is conveyed along
horizontal trunks, by means of Archimedean
screws, working in them, to a series of elevators
or buckets attached to an endless-band working
in a vertical plane over and under rollers at the
top and bottom. These elevators distribute
the meal among sixteen silk dressing machines,
each of which is 36 feet long, and 312- feet in
diameter, and inclosed within a casing of wood.
The silk machine consists of an octagonal
frame-work of wood, moving on a central axis,
to which it is attached by means of light bars.
The spaces of the framing are covered with
a fine carefully woven silk of hard texture,
stretched tightly. The axis is inclined three
quarters of an inch to each foot of the length:
the two ends of the machine are left open, and
the meal being poured in at the upper end, as
the machine revolves on its axis, each of the
eight sides is made in turn to act as a sieve.
But“ as this rotatory motion alone would not




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Fig. 2364.
flour mill in the world, is that erected within the last
few years in Upper Thames Street, London, and known
as the City Flour Mills. The mill, which is fire-proof,
is 260 feet in length, and 60 feet in width. There are
32 pairs of stones all furnished with the patent blow-
ing apparatus, the runner of each pair being worked
by a strap. A long horizontal trunk placed above the
mill-stones is supplied with condensed air by means
\
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bc sufiicient to separate the fine flour, in con-
sequence of the pores of the
silk becoming stopped up, a
vibratory motion is imparted
to each surface of silk at
the moment when it comes
into action. For this pur—
pose the light rods, which
connect the frame-work with
the axis, have wooden balls
or stout rings of wood
threaded loosely upon them,
so that as the axis revolves,
these wooden balls fall from
/
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.11
‘w'WzVZ/
‘s
S the axis upon the framing,
,; and from the framing back
again to the axis: it is in
A falling upon the framing
§§Q ’ that the vibratory motion
is imparted to the silk.
The fine flour which passes
through the machine pro-
ceeds down a shoot to ap-
propriate receptacles, and is
a finished product. The pollard, bran, &c., which do
not pass through, fall out at the lower extremity of
the silk machine, and are conveyed to suitable dress-
ing-frames.
The average quantity of wheat ground per week at
these mills is 2,500 quarters. The great advantage
of working with the patent—blast and with the silk
’,%¢r’
Q2
¢\4/
. machines, appears from the fact that, by this method,
WHEAT—WHEEL CARRIAGES.
989
wheat can be ground and dressed within the short
space of 15 minutes, during which time it passes
three times from the top to the bottom of the mill by
means of screws and elevators. Another advantage
of these arrangements is the comparatively clear atmo-
sphere of the mill, in consequence of the dust of flour
not being allowed to escape. Only a small number of
hands is required, most of the work of the mill being
performed by steam-driven machinery. The steam~
engine in this establishment
is on the marine principle,
and was formerly used as _

WITH THE SMOKE CONSUMING APPARATUS APPLIED.
The coals consumed were 49 tons in 57 hours, £ s. d.
or 1,925 lbs. per hour, consisting of all small
coals, at 17s. per ton 41 13 0
Or a cost . l‘ls. 7M. per hour.
Thus a saving is effected, by being
enabled to burn all small coals with
the smoke consumer applied, of .... .. 5 82 ditto
19 11
Or 361. 13s. 15,11. per week of 138 hours.
Engines driving same machinery as above.

one of the stationary engines
of the Blackwall Railway,
when the carriages on that
line were moved by means
of a rope. The nominal
power of the engine is 220
horse. There are seven
boilers for generating steam,
and the furnaces are made
to consume their own smoke
by the simple but ingenious
and highly effective plan of
causing one fire, as soon as
it is supplied with coals, to
discharge its smoke into the
next adjoining fire. The
arrangements by which this
method is carried out, will be
understood by referring to
the accompanying figures.
Fig. 2363 is a front elevation of a range of fire-
places furnished with Messrs. Bristow and Att—
wood’s smoke consuming apparatus. Fig. 2364
is as ectional plan of the same. Fig. 2365 is a
sectional elevation lengthwise of the boilers; and
Fig. 2366 is a sectional elevation taken across
the fireplaces. art are the fireplaces, bb the
fines leading therefrom into a, a fine common
to all the fireplaces, and leading to the chimney
d. When coals are about to be added to the
fire, theopening into the chimney is closed by
means of one of the dampers e e, and a damper
It is opened in a fine {/9 which extends from
end to end of the furnace, and affords a chan-
nel for the passage of the smoke from any one
fireplace to any other in the range. The plan
can be adapted to boilers at small cost, and is
equally applicable to marine boilers. The fol-
lowing comparative trial made on the 22d
March, 1854:, at the City Flour Mills, will
show the advantage of this apparatus :—





‘ / /' »
‘a tiff/‘1 ‘ will‘
WITHOUT THE APPLICATION OF THE SMOKE
CONSUMER.
The quantity of coals consumed was 62 tons £ s. d.
in 72 hours, or 1,9281hs. per hour, consist-
ing of 42 tons of Welsh, at 26s. per ton..... 54 12 0
And 20 tons of small, at 178. per ton............ 17 0 0
£71 12 0
Total cost of coal per hour, 19s. 1111.
The engines were driving at this time 26 pair of stones,
silk machines, and smutting machines.
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Fig. 2866.
The reason of‘ the ‘20 tons of small coals being
used in the above trial, was in consequence of having
two of J uckes’s patent furnaces at work, which have
since been taken out. . .
WHEEL AND AXLE. See S'ra'rrcs and DYNA-
MICS.
WHEEL CARRIAGES. The cars, carts, chariots,
vans, wagons, cabs, omni-buses, coaches, and other
990
WHEEL CABRIAGES—-WHEELS, TEETH OF.
vehicles which come under the designation of wheel
carriages, necessarily bear a resemblance in respect
to the principle of traction, however they may differ
in form and adornment. The sledge, the palanquin,
the litter, are examples of vehicles without wheels;
but of those which come more within the scope of
this article, we may say a little concerning carts and
wagons on the one hand, and pleasure carriages on
the other.
Modern improvements have rendered agricultural
carts and wagons far superior to those made 20 or
even 10 years ago. Mr. Pusey, in his Report of the
Exhibition Jury on Agricultural Implements, stated
that this improvement is very decided, and that a
single-horse cart will now render as much farm-service
in a day as a 2-horse wagon rendered a few years
ago. The chief source of improvement consists in
the substitution of iron for much of the wood—work,
whereby a diminished weight and an increased capa-
city are insured. This is also the case in another
class of merchandise-vehicles, the wagons and trucks
used on railways; the framework of these vehicles,
especially those on the broad-gauge made at Swin-
don, are constructed mainly, or indeed almost wholly,
of iron.
Pleasure-carriages are constructed with so much
care in England, that they have long been superior to
those made in any other country. Their varieties are
numerous; comprising landaus, coaches, chariots,
berlins, broughams, landaulets, britzschkas, barouches,
barouchets, phaetons, cabriolets, tilburys, curricles,
tandems, stanhopes, dennets, gigs, chaises, See. The
points in which these.difi°er are, that some are for 1
horse and others for 2; that some have 2 horses
a-breast, and others 2 horses in file; that some have
2 wheels and others 4!; that some are open and
others closed. Mr. Adams, in his “ Treatise on Plea-
sure Carriages,” describes a system of “equirotal
carriages,” which he has introduced: the system de-
pends upon a new adjustment of the under-framing
of Z.li-wheeled carriages, whereby all the wheels are of
the same size, thereby diminishing friction and in-
equality of motion: by a peculiar arrangement of the
pole or perch, the carriage can turn without the ne-
cessity of the front wheels passing under the body of
the vehicle. Although there is much ingenuity in
this invention, the equirotal carriages have not come
very extensively into use. The day of first-class stage-
coaches is past in England, and we can scarcely look
for any decided improvement in this class of vehicle.
Omnibuses, though strongly made, are deficient in
comfort and ventilation; it was expected that the
numerous omnibuses and models of omnibuses dis-
played at the Great Exhibition would have led to
improvements in the general construction of those
used in London; but such improvements are not yet
very apparent. ,
The coach~making art is one of the most elaborate
carried on in London. In no other are the materials
more carefully selected, or the processes more care-
fully carried on; and the workmen are in general
very highly paid. The wood employed is various in

kind. Ash is used for the skeleton frame-work of a
coach; heeeh is employed in inferior carriages; elm is
used for strong planking, and for wheel-naves; oah
is used for the spokes of wheels; mahogany is used
for panels or broad plain surfaces; cedar is sometimes
used as a substitute for mahogany; deal and pine are
employed in the flooring and roofing ; faslz'e, laneewood,
hz'r'eh, sycamore, chestnut‘, and plane-wood, are all occa--
sionally used in coach-making. The wood-work of the
“ body” is made by a wholly distinct set of workmen
from that of the “ under-carriage ;” body-making more
resembles cabinet-work, while carriage-making in-
volves the stronger processes of carpentry. The iron
work, and the works in the several metals, all call for
much care in their execution. But perhaps the most
remarkable operation in coach-building is connected
with leather-work. In common carriages the wood
is simply painted and varnished; but in carriages of
a higher class the upper part is covered with leather,
previous to painting. This leather covers the roof,
and also the upper half of the front, back, and sides;
yet it is all in one piece. A hide of leather, of large
size and of perfect quality, is selected; it is thoroughly
softened in water, and is thrown over the top of the
coach, the edges hanging down on every side. The
carrier or workman begins by rubbing the leather
down on the roof until it remains flat in every part;
he curries all the four sides in succession, until a
similar evenness is attained there also. But during
this process, as will be evident fromra little conside-
ration, there will be folds or wrinkles at the four cor-
ners; and the strange part of the operation is, that
by working the leather gradually from these corners
to the centreof the sides and back, the wrinkles be—
come rubbedrout‘altogether, and the‘ edges made as
straight, and even, and tight, as any other part. This
effect is due to the singularly pliant and yielding state
of the moistened leather. ~
The paint on a well-made coach is of considerable
substance. From 10 to 15 distinctmoats are laid on
the principal parts, each one dried and rubbed down
before the next is applied; and 6 or 8 coatings of
copal varnish prepare the surfaces for that beautiful
polish which is, perhaps, more durable and perfect
than in any other kind of wood-work.
WHEELS, TEETH OF. When two wheels act,
the one upon the other, by means of teeth, it is a
problem of much importance so to shape the teeth
that no motion shall be lost by undue friction between
the surfaces which come in contact. The teeth should
be formed in such a manner that
those of one wheel press in a
direction perpendicular to the
radius of the other wheel; that is,
the pressure should be tangential
to the wheel, as in the dotted line
to the right of fig. 2367, or tan- &
gential to the pinion, as in the
dotted line to the left. All arrangements of toothed
wheels come under what is termed the “,commu-
nication of motion by rolling contact.” There are
many designations of. toothedjvheels, according to.


w
' "I
<0’ ’
Fig. 2367
WHEELS, TEETH. OF.
991
the mode in which the teeth are arranged. An
ordinary tool/zed wheel .has the teeth cast or cut
‘in the wheel itself, forming one whole. A cog or
coggcd wheel has cogs of iron or wood, not formed
with the wheel, but inserted in its edge, or on its
face. A spnr-zo/iccl has, the cogs or teeth on the
edge or periphery, projecting radially from the centre.
.Aface—w/zcel has the cogs or teeth at the periphery,
but parallel to the axis of the wheel. A bcvcllcd or
nzilrc-w/iccl has the teeth formed upon a conical sur-
face, the angle of the cone depending on the angle
which the axes of the two wheels make with each
other. When two toothed wheels of unequal size
work together, the larger is generally called a wheel,
and the smaller a pinion. If the pinion is formed of
,a number of raised rods- placed between two circular
ends, it is called a handle or lantern. There are a few
other technical terms which must be understood, in
order to render intelligible the. reasoning respecting
the teeth of wheels. The wheel which imparts mo-
tion to the other is the driver,- that which receives
the motion is the follower. If, when the two are in
contact, a straight line be drawn from centre to
centre, thatxline is called the line of file centres; and
if circles be described from these centres, with radii
in the same nations the number of teeth in the two
wheels, those circles are pilot-circles. The measure-
ment of one complete tooth and its adjoining space
constitutes the ‘pile/i of the wheel. For example,
in fig. 2368, which represents a portion of the cir—
V’
m » f'“
,l _ t . ~~_-
,” §,::.\,\-—-J"’“'— ---:t:.
A
_ Fig. 2368. '
cumference of a pair of mill-wheels in gear, man
is- ‘the pitch-circle of the upper wheel, and c a c the
pitch-circle of the lower wheel. The forms of the
teeth are those usually adopted in practice.- The
distance a c constitutes the pitch, being one tooth
and one space; and the other dimensions are found
in certain conventional ratios to this pitch. Thus
dc, the depth to the pitch-circle, is =9, pitch; d f
the working depth 211% pitch; d9 the whole depth
: {6 pitch; ab thickness or width of’ tooth 2 T5,
pitch; 6 c breadth of space : T",- pitch.
In common mill-work, the sides of the teeth are
generally made arcs of circles, the friction or rubbing
being lessened by increasing the number, and con—
sequently decreasing the size of the teeth. For some
purposes the cpicycloid (or curve described by a
point'in the circumference of a small circle rolling
round the rim of the wheel) has been proposed; and
for others, that the side of each tooth ‘should be an
involzdc from the pitch-line, that is, that it should be

described by a pencil confined by a thread that is
unwound from that line. When the teeth are nu-
merous this curve will approach to a circular are.
There are frequently practical difficulties in giving
to the sides of the teeth the epicycloidal curve.
Equalization of motion is sometimes ensured in
toothed wheel-work by having two or more rows of
teeth on the same surface, succeeding each other
uniformly, so as to ensure the continuous action of
several teeth.
To form a wheel, the pitch circle AB all is first
drawn of the working diameter required for the wheel.
This circle forms the working circumference of the
wheel; for if two cylinders, equal in circumference
to the pitch circles of two wheels, be made to act
together by rolling contact, they would act similarly
to two toothedwheels, for we may consider the teeth
merely as enlargements of the roughnesses of the
wheels which act by friction or rolling contact; for
in such wheels, the working effect is promoted by the
roughnesses of one surface falling into corresponding
cavities on the other. In laying down, therefore, on
paper, two wheels which are to act together, their
pitch circles are described so as to be in contact, as
at A B, a b, Fig. 2369. They are next divided into as
many parts as
there are teeth
in the wheels,
each part being
made equal to
a tooth and a
space, or to the
distance be-
tween the cen-
tres of two ad-
joining teeth, as
at Pr’. This
distance r r’
forms the pitch
of the wheel;
0 c the line of
ccnlrcs; 1w the
pitch radii ,- and R’ r’ the real radii of the wheel. The
pitch of the wheel must not be too small, or the teeth
will not be strong enough to work. A series of
pitches is generally used for cast-iron wheels; those
for the larger wheels being 1, 1%, 1:15, 2, 21k, 3 inches,
and for small wheels, %, £3 1%, =3, &, inch. ~
To find the number of teeth in a wheel of given
diameter and pitch, or to find the pitch or the diameter
when the number of teeth is given,'is not difficult.
The circumference of a circle being'equal to the dia-
meter >< 3'M16, and the pitch being equal to a tooth
diameter X 31416
number of teeth
which the other quantities may be found; for ex-
ample :—-
No. of teeth A:


Fig. 2369'.

and a space, we thus get ’from
diameter x 3'1416 .
Pitch,
Pitch X No. of teeth
3‘14116


Diameter of wheel =
992 TVHEELS,
TEETH OF.
If, for example, it were required to make a wheel
two feet in diameter with 100 teeth, the pitch would be
24.‘ X 31416 ,
“100 = ‘754: 1n.
If the pitch in the same wheel were required to be
of one inch, the number of teeth in such case would
be '75; fol‘ Lxilém = 7 5. If the teeth were re-
quired to be of such a size that the pitch should
be % inch, and the number of teeth 120, the diame-
ter of the wheel would be then only 19 inches; for
-5 x 120 .
m=19 inches.
very nearly 1% of an inch ; for
A quicker method of finding the pitch is by dividing
the diameter of the pitch circle into as many parts as
there are teeth. This diametral pitch is some fraction
of an inch, and the denominator of this fraction will
be an integral number. Thus a wheel 10 inches in
diameter with 60 teeth, will have a diametral pitch
of %-g or %. The most useful values of this denomi-
nator, which may be called 1?, are 3, A, 5, 6, 7, 8, 9,
10, 12, 14, 16, 20. A wheel, in which the denomi—
nator of the diametral pitch is 6, is called a six—
pita/t wizeel. The circular pitch (which is obtained
by multiplying the diametral pitch by 31416) corre-
sponding with the above measures of the diametral
pitch are as follows :—
Value of P. Circular Pitch.
. 1 inch.
4.... i ,,
5... g ,,
6"’ n
7." "f"? g,
8... i} ,,
9.... ,,
10.... . {a ,,
12.... . i ,,
14... . ,,
16... . .3, ,,
20... . {;- ,,
The rules for forming the teeth of wheels vary
greatly; for some millwrights seek to obtain the highest
degree of accuracy; while others attach more value to
any method which is moderately accurate and easy of
fulfilment. The teeth ought, in any case, to be so
adjusted, that before one tooth has quitted its cor-
responding space, the next in succession will have
entered the next space; and so on continuously; con-
sequently the surfaces cannot escape from each other.
Professor Willis, in his “ Elements of Mechanism,”
gives one particular solution, applicable to trunnions
or pin-wheels; in which he shows that an epicycloid
traced on the pitch-circle of the driver by a describ-
ing circle equal to the pitch circle of the follower, will
drive a pin in the circumference of the follower with
the same motion as if the pitch-circles rolled together.
A second solution is given, applicable to the metal
toothed wheels now so largely employed. A third
solution affords the means of determining the shape of
the teeth in awheel which shall be able to act on
another having any greater or lesser number of teeth,
provided that in both wheels the teeth have the same
pitch. A fourth solution relates to involute teeth,
which differ from epicycloidal teeth in this,—that

whereas in an epicycloidal tooth the side is made up
of two different curves, joined at the pitch—circle, in
an involute tooth the entire side is formed of a con-
tinuous curve.
Workmen frequently adopt the following plan of
determining the form of the teeth of wheels. They
prepare template, that is, a pair of boards whose edges
are cut to the curvature of the pitch-circle and the
describing-circle respectively. The describing tem—
plet carries a point in its circumference; and by
rolling its edge upon that of the pitch-templet, the
are required for the face of the tooth is traced upon
the drawing-board. This done, the workman finds
with his compasses, by trial, a centre and small radius,
by which an arc of a circle can be described, that will
coincide as nearly as may be with the templet-traeed
epicycloid. Then, having struck upon the fronts of
the rough cogs a circle concentric with the pitch
circle, and whose distance from it is equal to that of
the centre of this small are, he adjusts his compasses
to the small radius, and always keeping one point in
the circle just described, he steps with the other to
each cog in succession, they having been previously
divided into equal parts corresponding to the given
pitch and breadth of the teeth. Lastly, upon each
cog he describes two arcs, one to the right and one
to the left, which serve him as guides in shaping and
finishing the acting faces.
Mr. Willis characterises this method as one pos-
sessing great practical convenience, and requiring
only a more commodious and certain method of de-
termining the centre and radius of the approximate
are. He thereupon sought to remedy this defect, and
to establish a working method which shall be easy of
use, and yet approach very nearly to mathematical
accuracy. He has invented for this purpose a small
instrument called an Oaiom‘ogmpit, or tooth-describer.
It is a sheet of cardboard, about a foot long, by 8 or
9 inches wide. Along the edge of one side is a series
of graduations, extending from 0 to 200, in a “ scale
of centres for the flanks of teeth,” and from O to 40
is a “ scale of centres for faces of teeth.” There are
also two printed tables on the card, to show the place
of the centres upon the scales. The tables include
any number of teeth from 13 to 150, and any pitch
from 1 inch to 3 inches; one table gives the centres
for the flanks of teeth, and the other for the faces.
In the works of Camus, Tredgold, Buchanan, Willis,
Barlow, and other writers on the principles of men
chanism, the mathematical. principles on which the
form of the teeth of wheels is determined, are fully
considered. We refer to those works for a full expo-
sition of the subject. -
On the subject of the teeth of wheels for clocks,
we have received the following communication from.
Mr. Denison :—-—
“ In setting out large clocks there are two points
which deserve attention. Both of them occur in the
great Westminster clock, which Mr. Dent is making
from my designs, and subject to the approval of the
Astronomer Royal and myself on behalf of the
Government.
WHEELS, TEETH OF—WHITI NG—W1NDMILL_..
993
“ (1.) The first case is that of the great wheel of the
going part having to drive a lantern pinion of 12, and
also the hour wheel of 418 teeth. The lantern pinion of
course fixes the shape of the great wheel teeth absc-
lutely, and therefore those of the hour wheel must be
accommodated to that shape, and cannot be radial
teeth as usual. For this purpose, the flanks of the
hour wheel teeth are traced by rolling on the inside
of its pitch circle a circle of the size of the lantern
pinion with a tracing point in its circumference. It
makes the teeth an odd looking shape, much thicker
than usual at the bottom; but the running is perfect.
This wheel being driven, with the action entirely after
the line of centres, no points, or projections of the
teeth beyond the pitch circle are required. If it had
had only 24 teeth they would have been of the common
form, since the same teeth will drive a lantern pinion
of n pins, and a common pinion of 2 n teeth or leaves.
And on the other hand, if this pinion of 12 had not
been made a lantern pinion, the teeth of the hour
wheel would have had to deviate still farther from the
common form. -
“ (2.) The other point is the form of the cams to
raise the hammer levers; and this is the more im-
portant because the rule given for it in Camus (which
seems to be the standard book with workmen) is
wrong, as I have noticed in my Rudimentary Treatise
on Clocks published in Weale’s Series, p. 215. I have
now got (from the suggestion of a friend) a more
simple rule for tracing the cams than the one I have
there given; it is this—Let AB, Eig. 2370, be one
division of the circle on which the cams are to be



Fig. 2370.
traced; through A and 13 draw tangents, intersect-
ing at T: T B will be the radius of a circle 13 P, which
is to be the face of the cam. It is evident, that the
lever o A will always be a tangent and never scrape on
this cam, and also, that at the point I’, where it drops
off, it will be a tangent at its and, and therefore, the
point of the cam will not scrape on the lever. The
velocity of raising is not quite uniform, but that is of
no consequence, for the reason mentioned in my book.
This plan also has the advantage that only the length
and not the curvature of the cam depends on the
length of the lever, and therefore the same pattern of
cam will do for levers of various lengths.
“ You will easily conceive that every bit of friction
is of consequence in this great clock, when I tell you
VOL. II.

that the pressure on the hour striking cams will pro-
bably be not less than 8 cwt.”
WI-IET SLATE. See Horus.
WHEY. See MILK.
WHISKEY. See DISTILLATION.
WHISTLE, STEAM. See STEAM-ENGINE. .
WHITE-LEAD. See LEAD.
WI-IITING is prepared by grinding chalk under a
runner, then washing it in order to remove sand and
other impurities, and lastly drying it in lumps. The
particles of chalk in this state are so soft as not to
abrade materials of tolerable hardness, and hence
whiting is used as a finish in polishing metals, but'its
use for this purpose seems to be chiefly in absorbing
the grease left in the previous processes.
WIGK. See CANDLE—LAMP.
WINDING MACHINE. .See GALIco PRINTING.
Fig. 415.
WINDLASS. See GAPSTAN. In small vessels, the
capstan is worked with the barrel in a horizontal po-
sition, in which case it is called a windlass. The power
is applied by means of levers, which are worked in
holes similar to those in the capstan-head.
WINDMILL. The principal parts of awindmill con-
sist of an axle, A, A, Fig. 2371, inclined to the horizon
from 8 to 15°, and 4' wooden sail—frames, V, v, each
‘v

Fig. 2371. snc'rron or common wmnmrnn.
about 40 feet long, attached at right angles to the
upper extremity of the axis. Each sail-frame or 10122)),
as it is called, consists of along bar of wood with short
pieces projecting therefrom at right angles, the outer
extremities of these short pieces being connected
together by a vertical lath of wood; on these frames
sail-cloth is spread, so as to form a continuous sur—
face capable of arresting the air in its, motion and
receiving therefrom the amount of pressure required
for the revolution of the 11 arms: each sail begins at
3 s
1904
WINDMILL.
about 6% feet from the axle A, and terminates at the
extremity of the arm which supports it. The arms
taper off towards the extremities. The frame—work
which supports the mill turns round on a fixed ver-
tical axle r, and a lever L is used for turning the
frame-work so as to direct the axle A towards the
wind. In some cases the roof only of the mill is
movable ; it is then circular in form, and revolves
upon rollers, M‘, Fig. 2372. This kind of mill is
usually of stone in the form of a round turret, with
a large wooden ring on the top. To produce the
motion in the roof, the wooden ring on the top of
the building is furnished with a groove, containing
‘a number of brass trnckles at certain distances apart,
upon which, and within the groove, is placed another
ring, on which the whole roof is supported. Beams
are connected with the movable ring, and to one of
them is fastened a rope, and attached to a windlass at
the lower extremity, the rope is drawn through an
iron hoop fixed at the ground, and the Windlass being
turned round the sails ‘and roof will be turned round
also. One objection to this construction is that the
roof is liable to be blown off in a very high wind. As
these methods of adjusting the windshaft must be put
in operation by hand, a contrivance has been made
for setting the sails by the action of the wind only.
For this purpose a large wooden vane or weathercock
v, Fig. 2372, is fixed to the extremity of a long



E59. 2372.
horizontal arm lying in the same vertical plane with
the windshaft, by which means when the surface of
the vane and its distance from the axis of motion
are of sufiicient ‘magnitude, a gentle wind will act
upon the vane, so as'to move the sails s s, and wind-
shaft to their proper position. This plan may be
adopted whether; the mill have a movable roof or
revolve on a vertical shaft.
The axis A, A’ makes an angle of from 10 to 15°
with the horizon, because it has been observed that
the direction of the wind is not generally horizontal,
but describes a small angle with the surface of the
earth: So also the surfaces of the sails are not placed
in a plane perpendicular to the axis A, A’, but are
slightly inclined therefrom, so as to receive the action
of the wind somewhat obliquely. The sails are in fact
arrangedin such a way, that the pressure which each
one undergoes shall tend to turn the axis A, A’ in one
direction. ‘But the obliquity of the surface of the
sails with respect to the direction of the axis A, A’
varies somewhat in the length of each sail, diminish-
ing 'from the axis to the further extremity of‘ the sail.
In well-constructed mills that part of the sail nearest
the axis makes an angle of 60° with the direction of
this axis, while the other extremity of the sail makes

an angle of 80° therewith. This change of obliquity
is required to meet the varying velocity of the sails
at different points of their revolution. “According
to Monge and Hachette each sail may be regarded as
an irregular surface engendered by the motion of a
right line perpendicular to the piece which sustains
the sail, and which at the commencement of the sail,
viz. nearest the turning axle, would form with it an
angle of 60° on the windward side of this right line,
passing over the whole length of the piece sustaining
the sail, and remaining always perpendicular to it,
but uniformly increasing the angle which it forms
with the turning axle in such a manner that, at the
extremity of the sail, the angle, which was 60° at the
commencement, would become 78° if the axle A were
inclined 8° with the horizon, or 841° if the inclination
were 15°, and in proportion for intermediate inclina-
tions. The position of the generating line serves to fix
the direction of the cross pieces; together they form
a frame which receives the sail-cloth: each sail may
also be regarded as an irregular surface produced by
the motion of a right line perpendicular to the piece
sustaining the sail, and subject to touch in all its
positions the right line drawn through the corre-
sponding extremities of the position which the ge-
nerating line should have at the two extremities of
the sail as previously stated.” It has been estimated
by Coulomb that the total effect of a mill of this de-
scription working throughout the year 8 hours a-day
is equal to the raising of a weight of 1,000 lbs. 218
feet per minute, an efiect equal to the daily work of
61 men. According to Euler, the mill is acting with
greatest efliciency when the velocity of the extremity
of the sail is to that of the wind as 2 : 1.
When the wind is blowing strongly, it may be ne-
cessary to check the rapidity of motion in the arms,
otherwise the moving parts might take fire by the
friction: for this purpose, some of the canvas is taken
in, by means of a rope properly adjusted, and which
also serves for spreading out the canvas when it is
required to expose a larger resisting surface to the
wind. In either case, the adjustment requires the
stoppage of the mill. Accordingly plans have been
devised for rolling and unrolling the sails while in
motion; but these plans do not seem to have come
into general use.
When it is required to stop the mill, a break or
gripe may be applied to the crown-wheel w, or the
sails may be drawn down from the ends of the frames
towards the axis A, and when it is required to set the
mill in action, a man ascends each arm in succession,
dragging the sail after him, and he adjusts it while a
man below holds the opposite arm. In this operation
the sails should be turned away from the wind. On
the continent sails have been contrived on the prin-
ciple of louvre boards, which are made to open and
shut by means of racked bars attached to the axis.
The windmill is chiefly used in this country. as
a power for turning a millstone in grinding corn; for
which purpose, a crown-wheel c, Fig. 237 2, is at-
tached to the axis, and the teeth of this wheel engage
with those of another wheel L, attached to the ver-
WINDMILL-—W1NE.
9'95
tical axis of the millstone M. On the continent, the
windmill is used as a power for driving saw-mills, oil—
mills, for working the pumps used in draining, and for
other purposes.
In situations where the great height required for
the vertical sails would be an objection, the lzorz'zorzlal
windmill may be used, although it is stated that such
a mill has not much more than l-fourth of the force
of a vertical mill. A horizontal windmill consists of
a wheel or ‘fly formed by 6 sailbeams fixed to a cen-
tral axis, as shown in Fig. 2373 ;
to these beams are attached
vanes placed so that their sur-
M faces may be divided into two
unequal parts by the axis of
rotation. It must be evident,
that however the vanes are ar-
ranged, while some of them are receding from the
wind and causing the vertical axis to rotate, other
vanes, in coming up to the wind, must produce so
much friction or resistance as greatlyr to diminish the
effect. Mr. Beatson attempted to overcome this
dilllculty by so arranging the vanes that the whole
force of the wind might act in a direct manner on the
resisting side, but when acting on the other or re-
turning side, the parts of the vanes should give way
and allow the wind to pass through. For this pur-
pose the vane frames were filled up or covered with
canvas or other light material in such away as to form
small separate parts or flaps, placed so as to overlap
each other a little; by which means the flaps would
be close shut when the wind was acting directly upon
them, and the vane would receive its whole impulse
just as if it consisted of one entire piece. But when
a vane comes up to the wind the spaces are all open,
the wind blows through, and the vane offers but little
resistance. A better plan is to enclose the fly in a
fixed cylinder, or screen formed by a number of louvre
boards, arranged so that in whatever direction the
wind may blow it may enter between them on one
side only of a vertical plane, passing through the axis
of the fly. In this way the wind acts upon the ob-
lique surfaces of the boards on one side only of the
axis, while the screen prevents the wind from acting
upon those vanes which are coming round in the op—
posite direction.
WINE. The fermented juice of the grape. At a
very early period in the history of the world, wine
was produced by fermenting the juice of the grape,
as is proved by the frequent notice of it in the most
ancient writings. In many respects, however, the
wines of the ancients differed from those of the mo—
derns. They frequently had the consistence of li-
queurs, and were impregnated with highly odorous and
sapid substances ; but they all contained alcohol, and
had exhilarating or intoxicating qualities.
The wines of modern times are exceedingly numerous.
Some chemists apply the term wine to every saccha—
rine solution the sugar of which has been wholly or
partially changed into alcohol. This is not generally
done, although we are accustomed to apply the term
wine to other fermented juices than those of the


Fig. 2373.

grape, and to distinguish them therefrom by naming
the sources whence they are derived. Thus we speak
of ginger-wine, gooselewy-wz'rze, curmrzl-wz'ue, &c. ‘The
juices of various plants contain certain fermented
saccharine fluids; thus the beetroot and the parsnip
yield a fermentable juice; as do also the stems of the
birch and cocoa palm; the spatha of the Sagas vim‘-
fem and other palms, the leaves of the vine and
various kinds of fruit, such as gooseberries, currants,
&c. The conditions under which a saccharine solu-
tion by the addition of a ferment, such as yeast,
changes its sugar into< alcohol, have already been
treated of under FERMENTATION——BEElt——ACETIG
Acin—Suean—S'rancn—GUM. By the more or less
perfect conversion of the sugar of the vegetable juices
during fermentation into alcohol, this substance is
always present in wines, yet other substances are also
present, the number and relative proportion of which,
and the mode in which they are blended together,
give to wines their distinctive qualities.
In the present article we shall confine our atten-
tion to the juice of the grape, which is by far the most
important in wine making. The Villa m'nifem has a
very considerable geographical range, extending from
nearly 55° N. lat. to 415° S. lat. The grapes grown
within this wide range are not all adapted to the
making of wine. In Konigsberg the grape only ripens
in warm summers, and is deficient in sugar, while in
southern regions the sugar is so abundant as to crys-
talize in the grape, while those acids are absent which
are necessary to the flavour of the wine. Where
much sugar is present, other conditions being favour-
able, rich sweet wines, known as m'ns ale liqueurs, are
prepared, such as Frontignac, Lune], and Rivesaltes,
prepared in the south of France from the Muscat
grape, which on the Rhine furnishes a grape fit only
for dessert. The local conditions which influence the
quality of the grape are numerous, and often perplex-
ing. The same latitude does not always allow the
growth of a good wine-making grape: the position of
the isothermal lines, the degree of moisture, the clear-
ness or cloudiness of the atmosphere, appear to be of
evenf'greater importance than the composition of the
soil: indeed it appears from recent observations that
the ripening of fruits depends more on the illumi-
nating rays than on the heating or chemical rays.
The different climates in which the grape ripens im-
part to it certain distinctive characters: the grapes
which are grown along the Maine or the _Rhine, and
which yield Hock, furnish Bucellas when grown‘near
Lisbon, and Cape Hock, when grown at the Cape of
Good‘ Hope, a very different wine from the Rhenish.
When grown at Madeira, the same sort of grape yields
the Sercz'al, which differs from all the preceding. The
composition and qualities of the soil have also some
influence: when the‘soil is dark in colour, such as
that formed by argillaceous schist, it radiates heat by
night as well as by day, and the grape ripens easily.
According to Chaptal it is of most consequence that
the soil be ‘porous, free, and light; its component
parts being of secondary importance. Calcareous soils
are said to be the best, because'they readily imbibe
3 s 2
996
WINE.
the rain, and allow a clear atmosphere to surround the
vines. When differences occur in the quality of the
same grape in the same district, and even in the same
vineyard, slight variations in locality must be assigned
as the cause. When the vine is planted on the side
of a hill or mountain, the wine yielded by the grapes
from the higher part of the slope will differ essen-
tially from that afforded by the grapes of the lower
part; thus the Jolzanm'sderger and the Rz'ielz'sfieimer
are the produce of contiguous vines which resemble
each other in external characters. Johannisberg is
only 150 feet above the level of the Rhine, and yet
the produce of the summit near the castle is of a very
superior quality to that produced in the Johannisber-
gerhole or hollow; because in the former case a large
and wealthy proprietor can command the best treat-
ment for his vineyard, while the latter, being much
subdivided, is cultivated with less skill. Moreover,
the upper vineyard is surrounded with a stone wall
ten feet high, which, by sheltering the grapes and
securing a quiet state of the air, allows them to at-
tain maturity under more favourable circumstances.
This sheltering of the grapes is so evident in its
effects in the Rheingau, that belts of vineyards which
clothe the height of Hochheim, produce different
wines according to their position One morgen or
acre close to the bed of the Maine, fetches 2,000
florins in the market, a higher morgen 1,000 florins,
and one at the summit only 500.
Wines of high reputation, however, owe their cha-
racter to other circumstances, such as the variety of
the grape and its mode of culture, selecting the most
favourable time for the vintage, gathering and press-
ing the grapes with such rapidity that the contents of
each vat may be in the same state, so as to secure a
simultaneous and equal fermentation throughout; ex-
ercising judgment and care in the time and mode of
drawing off the wine, and in its subsequent treatment
in the casks where it is kept, and not selling the wine
until it has acquired perfection, and only selling such
vintages as are calculated to maintain the celebrity
of the vineyard. In this way a few large proprietors
have obtained for their wines a celebrity which is
usually ascribed to locality or to something peculiar
in the soil.
There are cases, however, in which a wine may be-
come tainted through the presence of certain sub-
stances in the soil. Thus stinksz‘one, a native sub-
carbonate of lime, will give a repulsive taste to wine,
which however comes to be relished in time, and
hence the taint is not eradicated. In France and
Portugal a strong opinion is maintained that manure
deteriorates the flavour of the wine. The German
cultivators, on the contrary, manure freely, not only
with fresh cow-dung, but also with fragments of
woollen cloth steeped in liquid manure and dried,
and the produce is greatly increased thereby. This
is not done very frequently, but at intervals of three
or four years for red grapes, and of nine or ten years
for white grapes. A valuable manure for vines con-
sists of the cuttings of the vines themselves when
pruned at the end of July or beginning of August:

the fresh and moist prunings should be cut into small
pieces and mixed with the earth, when they undergo
putrefaction so completely as to disappear at the end
of four weeks. They restore to the soil a portion of
the alkalies abstracted by the grapes.
Vintages vary in character from year to year, no
two successive vintages being probably identical in
flavour and perfume, and it may happen that a season
favourable to the vintage of one place is unfavourable
to that of another: thus the good Port years rarely
coincide with the good Claret years, for the heat
which brings to maturity the grapes in the compara-
tively cold climate of Medoc, scorches the grapes of
Alto Douro, and vice versa”.
The aspect of a vineyard must depend on the lati—
tude and longitude of the district and on other cir-
cumstances. At Bordeaux a south-cast exposure is
preferred; in Germany, a south-west; in the north of
France, a northern aspect is thought best. The
locality should be a gentle acelivity, if possible, as-
cending from the bed of a river, the vapour from
which, if not excessive, preserves the skin of the grape
in a soft thin state, which is favourable to the passage
of heat. High elevations are unfavourable, with one
or two exceptions, such as the Malaya or Mountain
wine of Spain, which is grown many thousand feet
above the level of the sea. Vines bear wet badly,
especially that of land springs.
The vines should be kept low, for it is found that
the nearer to the ground the grapes grow, the more
potent is the wine; the earlier also do the vines flower,
and the grapes become ripe. Grapes on the lower
branches are often ripe first, although shaded by the
leaves from the direct rays of the sun. It has been
suggested that the bouquet of wine is due to the
bunches of grapes thus sheltered. The frosts of spring
and the hail-storms of summer are injurious to the
vine, as well as excessive wet in spring or autumn.
There are also numerous insects which infest it.
The varieties of the vine are exceedingly numerous,
between five and six hundred having been named.1
The grape which ripens soonest is preferred, and it is
generally found that red grapes ripen 10 or 12 days
before the white. It is of importance in making
wine that the grapes shall all have attained the same
state of maturity. At J ohannisberg and other famous
vineyards on the Rhine, three successive gatherings
of grapes are often made at considerable intervals,
and every unsound grape is removed from each bunch
as it is discovered. The state of maturity is one of
the circumstances which determines the quality of the
wine : for a brisk wine, such as Champagne, the grapes
are gathered before they are quite ripe, but for the
most esteemed German wines the gathering of the
grape is deferred as long as possible in order to get
rid of many free acids. This plan of late gathering
has been found so successful, that new wines made
from late gathered grapes have been found more soft
and delicate than extremely old wines made from early
gathered grapes. In some of the most celebrated

(I) In Mr. Busby’s “Visit to the Vineyards of Spain and
France,” a list of 570 varieties is given.
~WINE.
997
bouquet of the Wine.
vintages of Johannisbcrg the grapes have been hang—
ing on the vines as late as October and November. In
the warmer parts of the South of Spain and of France,
and also at Tokay, the grapes are left for a long time
upon the vines; the stalks being twisted to prevent
the entrance of recent sap, while the thinner or watery
portion of the sap evaporates from the fruit, which
becomes dry and shrivelled and resembles raisins:
from such grapes are made the Vz'us. a’e liqueurs. On
the Rhone some of the ripest grapes are selected and
hung upon hurdles, or spread upon straw for 6 or 8
weeks: the sweet wine prepared from the-m is known
as Via ale paille, or straw wine. A sweet luscious
wine is sometimes made in Spain by boiling the must;
the wine of Cyprus is thus produced, also the Vz'uo
Gotta of Italy (the Via-um cocz‘um of the ancients), the
original Malmseys of Candie, and other rich wines of
the Grecian archipelago.
The chemical composition of grape-juice is compli—
cated. The juice of the unripe grape, called oery'uz'ce
or green juice, contains, according to Geiger, as fol-
lows : A deposit from the juice contained chloro-
phyll, wax, tannin, and glutinous matter: the filtered
juice contained tannin, extractive, uncrystallizable
sugar, gallic acid, free tartaric acid, (about 1'12 per
cent.,) free malic acid (about 2'19 per cent.,) bitartrate
of potash, malate, phosphate, sulphate, and muriate of
lime. The juice was that of the white grape of good
quality. The juice of the ripe grape called must con-
tains, according to Proust, extractive or colouring
matter, granular and uncrystallizable sugar, gum;
glutinous matter, a little malic acid, citric and tarta-
ric acid, and hitartrate of potash. Some other salts
have also been found in must, such as tartrate of
lime, tartrate of alumina and potash, sulphate of
potash, chloride of sodium, and chloride of potassium.
In some kinds of grapes there are raeemates or para-
tartrates, which probably replace the tartrates. Traces
of an oily matter are also found, derived either from
the juice or from the seeds or husks; they have an
important influence on the colour and flavour, or
The colouring matter of the
grape resides entirely in the skin, except in the grape
known as Tz'ut‘z'lla, from which the tent wine of Spain
is prepared : this grape is coloured throughout, and is
used in dyeing: the French term it tez'utu'rz'er or l’alzl
caut‘e. The colour of the wine, however, does not de—
pend upon that of the grape, for Champagne is made
from a red grape, and Sherry is made from red and
white grapes without distinction. The fermentation
of the juice is promoted by the presence of the stalks,
and if they and the skins are removed before the for-
mentation has proceeded far, they do not impart
either colour or flavour to the wine, although the
skins may be of a deep colour, the presence of alcohol
being required to dissolve the colouring matter. They
are removed at an early stage, in the case of the deli-
cate red wines of Bordeaux ; but are allowed to remain
longer in the red wines of Portugal, which accounts
for their greater astringency. The wine of Cahors
has its colour deepened by the addition of a dye-stuff
called Rau‘r/ome, prepared by boiling for a few minutes

1 part of strong spirits of wine with 11' parts of must.
The wines of the Moselle have a greenish colour, and
those of the Rhine a yellowish colour. The broker
judges of the colour of wine by placing a small quan-
tity of it in a small silver saucer or tamhulaclez'ra (as
it is called in Portugal) : it is slightly raised in the
centre. When this is agitated, the wine passing in a
thin layer over the convex part exhibits the colour
well. Casks for holding red wine should not be
fumigated with sulphurous acid, which destroys the
colour, but be rinsed out with spirits of wine.
Red wine is more delicate and liable to injury in
the making than the white. If the grapes be gathered
before they are sufliciently ripe, the wine is likely to
be raw or wart, which is one of the greatest defects in
wines, for they become hard by keeping. If the grapes
be over—ripe, they are liable to putrefy before being
gathered; the wine made from them works long in the
barrels, and readily becomes sour. A few details of
the processes of wine-making in the south of France
will show the general method of conducting this
branch of industry.
The celebrated wines of Bordeaux (known as Clarets
in England) are for the most part grown on a long
tongue of land situated to the north of Bordeaux, be-
tween the sea and the Garonne and Gironde: it is
called Ma’doc (quasi'medio aquae), because it is nearly
surrounded by water. It forms the north termina-
tion of that extensive region of sand known as Les
Landes, and is nowhere more than one or two miles
broad: it is raised from 50 to 80 feet above the river.
The soil of Médoe is a light‘gravel, and in many parts,
even where the best wine is produced, consists of
rolled quartz pebbles mixed with sand. In fact,
where scarcely a weed will grow, the stunted vine
produces grapes of the first quality. This stony soil
retains so much of the heat absorbed by day, that by
its radiation at night, it works (traoaille, as the people
of the country say) as much by night as by day. The
vine begins to yield grapes at 5 years of age, and is
said sometimes to continue productive for 200 years.
The wines are classed into growths (crus), but only a
very ‘small portion of the strip of land produces the
premiers crus, and often within a few yards of the
finest vineyards none but an inferior grape will grow.
The Bordeaux wines of the first growth are known as
the Chateau lllargaaa', the average quantity of which
produced in one season varies from 14.0 to 160 tuns,
(the tun or touueau containing at hogsheads or, bar-
rz'quca) Chateau Lafitte 120 tuns, Chateau Latour 120
tuns,Hautl Brion from 60 to 80 tune. The last is pro-
perly a Vz'u do Grave, since it is grown on the Garonne
above Bordeaux. Médoc wines of the second growth
are Mouton (Lafitte), from 120 to 1/10 tuns; Le’ovz'lla,
the best of the wines of St‘. Julian, from 14.5 to 186 tuns ;
and Rauzau (Margaux), from 76 to 95 tuns. There
are also La Rosa Gruau, Pz'chou, Louyueoz'lle, Bur/‘art,
Dar/arse, Laseomha, Cos-Destouruellc; in all about 800
tuns. Wines of the third, fourth, and fifth growths,
are many of them produced in the vicinity of the first-
rate vineyards, without partaking of their excellenees.
So much, however, depends on the season, that. when
9 0.8
WINE‘.
this is highly favourable, second class wines may be
raised to the rank of the first, and in bad seasons first
class wines will fall below the second. In had years,
wines which would otherwise be sent to England
are transported to Holland, or retained in France;
and so much had this become the custom, that the
proprietor of the vineyard of La Rose was accus—
tomed to hoist on a flag-staff above his house the
English flag in good years, the Dutch in middling,
and the French in had years. England receives more
than one—half of the premiers eras, and very little of the
inferior sorts; Russia takes a considerable quantity;
Paris a small quantity of the best; wines of the second
quality go to Holland; and the third sorts, or wins or-
dz'naz'res, are chiefly consumed in France. The wines
for the English market are mixed with strong bodied
Rhone wines, chiefly with lzermitage. The average
price of a hogshead or barrique of genuine wine of
first growth, in the cellar of the first houses .of Bor-
deaux, is 501., which, with carriage, duty, bottling,
&c., amounts to 801., or rather more than 7 Os. a
dozen.1
In making Claret, the wine-vessels are first cleaned,
and rinsed with the strongest spirits of wine, or even
with brandy, and the grapes being gathered, the rot-
ten bunches, and those which are not ripe or are
withered, are picked out. A cure-mere, or mother-
cask, is first prepared with the best fruit: the grapes
are put in without their stalks, and without treading
them, in a layer from 15 to 20 inches deep; 2 gal-
lons of old Cognac or Armagnac is poured on them,
another layer of picked grapes, then 2 more gallons
of brandy,- and so on until the cask is full. From 2
to 4*.‘ gallons of spirits of wine are lastly added, 4! gal-
lons being used for a vat of from 30 to 36 tune. The
quality of the vintage, however, regulates the quan—
tity of brandy or spirits of wine required, a larger
proportion being used if the quality is bad. In bad
years, when the grapes do not contain a suificient
quantity of saccharine matter, it is now customary to
supply the defect by the addition of glucose or starch
sugar. When the cuve-mere is filled, it is closed se—
curely and covered with blankets, and left for 3 or 4!
weeks. In order to ascertain the progress of the fer-
mentation, and the exact time for racking ofi, a small
brass cock is inserted at the side of the vat, at about
the height of one-third of its depth from the bottom.
When the liquor has become cool and tolerably clear,
it is fit for drawing off. While the fermentation is
going on in the mother-cask, the vintage is continued
in the usual manner; that is, as the grapes are
brought in- and picked, they are trodden in the press,2


and put with their stalks into vats, where the fer-
mentation takes place naturally. The vats are filled
to within 12 or 15 inches of the top, the vacant space
being left in case of overflow, which sometimes
happens when the grapes have attained perfect matu-
rity. The stalks, skins, and seeds, which float on the
surface of the wine, form what is called the c/mpeau.
The vats are lightly covered and left to ferment;
they are carefully examined about twice a-day, and
in from 8 to 12 days, according to the goodness of
the vintage, they may be racked. The time for rack-
ing is a critical point; for if the wine be left too long
upon the lees, or with its crust or chapeau on, it will
imbibe the disagreeable flavour of the stalks; if racked
ofl" too soon, the wine is liable to fret in the barrel
and become sour. The wine is racked ofi‘ into barrels,
(prepared by scalding and rinsing with a little spirits
of wine,) which are filled about 9,; or :2; the mother-
cask is then emptied, and equal portions of its con-
tents are poured into the barrels, a quantity being
reserved from the mother-casks to supply the loss
which the barrels may sustain from evaporation or
ullage. The barrels are left 8 days without being
bunged, but the bung-holes are lightly covered with
a stone or piece of wood. They are filled up every 2
days, and when bunged, every 8 days, until the wine is
in such a condition that the cask may be, kept with the
bunghole at the side: this takesat least 18 months.
In making white wine, the grapes are trod, and
when taken from the press the stalks are separated,
and the juice, skins, and seeds, are put into casks to
ferment. When the wine has been racked off, care is
taken to keep the barrels full by filling up once or
twice a-week.
It will be seen that the production of wine involves
fewer and simpler processes than the brewing of beer.
The wine, the result of the above. operations, should
be clear and transparent, of a fine soft colour, and a
lively smell, balsamic and slightly piquante in taste,
filling the mouth, not irritating the throat, gently
warming the stomach, and not quickly affecting the
head. The save or flavour of the wine, and the hou-
quet or odour, are properties resulting from very dif-
ferent sources. The flavour appears to be due to the
alcohol and the aromatized particles set free by the
warmth of the mouth and stomach. The bouquet is
due to the generation of a peculiar ether called
(enact/no.3 In some wines, the save and the bouquet
are produced only by age. A fictitious bouquet, how-

4‘
(1) Murray. “ Handbook for Travellers in France.”
(2) An English visitor to one of the vineyards of this district
thus‘ describes the operation of pressing :—The music strikes up,
and the first cart tumbles its precious load through a wide sort of
arched window into the great cistern, which stretches along just
below the level oilitszsill. There were three of these openings in
the length of the building; and each cistern was manned by six-
teen men in merely their white shirts, and short breeches tucked
up above the, knee, showing the brawny legs and bare feet which
were soon to tread a measure to the old fiddler’s lively melodies.
A strange effect it had to our English eyes when these rough-
looking beings, taking their places opposite to each other,
began a set of quadrilles in a most decorous manner, at every
step crushing down the once beautiful fruit, whose juice runs out
at an aperture in one corner into tubs, beside which a man
watches lest they should overflow. Before the ball commences,
there is a very large wire frame or cullender placed over the
shallow cisterns, in which the men rapidly separate the stalks
from the fruit; the latter falling through, and the stalks being
carried to another cistern, where a man with a small kind of rake
picks ofl’ any grapes remaining on them. These stalks are then
piled up in apress, and the liquor they yield makes an inferior
drink for the lower classes. As the juice streaming from the
presser’s cisterns filled the tubs, they were borne awaycn poles
between two men, and thrown into great vvats, with the skins of
the grapes, where all is left to ferment—Chambers’ Edinburgl
Journal, No. 214, N.S. -
(3) Flower of _Wine,_~from ol'uoc, wine, andjiwoe, a flower.
WINE.
999
ever, is sometimes given by adding several species of
sage and rue to the fermenting liquid, or by hanging
in the cask into which the wine has been racked, for
about 15 days, a muslin bag containing 2 drachms of
powdered orris—root. A fictitious flavour is also given
by means of raspberry-brandy.
It was formerly supposed that the bouquet of wines
was derived from the grapes themselves; and hence
it was, and we believe still is, customary to suspend
some of thc ripest and most odoriferous bunches of
the grapes in the cask after the first fermentation had
subsided. It has, however, been shown by Pelouze
and Liebig, that the smell and taste which distinguish
wine from all other fermented liquors are due to an
ether of a volatile combustible acid, resembling one
of the fatty acids, and named oenanthic- el/zer, as already
noticed. CEnanthic acid is represented by the formula
CHHISOQ, and the addition to this of CiHsO, gives
0181-1180:, as the composition of oenanthic-ether. This
ether was first separated from the wines of Burgundy,
and it has been found with amylic alcohol, or po-
tato'spirit oil, in the products of the distillation of the
grape-stalks of Montpellier. It has been supposed
that the odorous compounds which form the bouquet of
wines originate in the fatty acids of the grape, which,
by oxidizement, are converted into the more powerful
acids better capable of forming ethers. It appears,
however, to be only in liquids which contain other
very soluble acids, that the fatty acids and oenanthic
acid are capable of entering into combination with
the ether of alcohol, and of thus producing the vola-
tile odorous compounds. This ether is found in all
wines which contain a free acid, and does not exist in
those which contain no acid. Tartaric acid, therefore,
seems to be the means by which the bouquet in wines
is produced. If a different organic acid be present,
such as the acetic, the peculiar taste and odour will
be wanting. The wines of warm climates have no
odour; those of France have it in a marked degree; ,
and it is strongest in Rhenish wines. Those grapes
which are grown on the Rhine, and known as the
Riesslinp and the Orleans, ripen late, and seldom at—
tain maturity ; they afford the strongest bouquet, and .
contain a proportionately larger quantity of tartaric
acid. Grapes which ripen earlier, as the Ralmzder,
yield a large proportion of alcohol, and resemble
Spanish wines in flavour, but have no bouquet.
The fermentation of the must is best carried‘on in
large casks, covered over to prevent the escape of car-
bonic acid, alcohol, and aroma. The time required for
the fermentation depends on the kind of wine and
the temperature. In the Champagne district, the
grapes required for one cuve are all pressed within
a couple of hours, and left from 6 to 18 hours, when
the must becomes quite clear, an event which is
watched for with great anxiety. The must is drawn
off into wcll-sulphured casks, and put into unden-
ground cellars; the bung-hole is covered with a flint-
stone; and the yeast which overflows is occasionally
removed, until December or January, when the wine
can be tasted and proved. In this condition it is sold,
and then undergoes the operation of fining.

The primary or active fermentation is succeeded by
a secondary or inscnsible fermentation, a continuation
of the first, but which requires careful management.
The contact of the air will excite fermentation in the
juice of the grape, the sugar of which will be con-
verted into alcohol and carbonic acid. [Sec Fan-
MENTATION.] In addition to these products, an inso-
luble nitrogenous substance called yeast is also formed
from the azotised constituents of the grape-juice;
also called gluten, or vegetable albumen. This yeast
has the property of inducing fermentation in a new
solution of sugar, whence it is called a ferment. Gluten
appears to act towards sugar as diastase does towards
starch, by imparting that impetus to it which enables
it to alter its condition. When gluten and sugar are
both present in a liquid, fermentation proceeds until
the decomposition of one or other constituent is com-
plete. When the quantity of ferment is too small in
proportion to the sugar, its putrefaction will be effected
before the whole of the sugar is converted into alco-_
hol and carbonic acid. This happens in the case of
sweet wines which contain unchanged sugar, the
cause of its decomposition being wanting, namely,
contact with a body in a state of decomposition.
When, however, the quantity of ferment predominates,
some of it remains after the whole of the sugar has
been transformed, and thenits decomposition proceeds
very slowly in consequence of its insolubility in water.
The grape-juice of different climates contains very
variable proportions of free acid and of sugar; but
the quantity of azotised matter in the juice seems to
be tolerably constant. As the presence of sugar, in
wine in an unchanged state, produces asweet wine in
which the conditions required for further change are
absent; so, on the contrary, these wines which contain
not an excess of sugar, but variable quantities of un-
decomposed gluten in solution, are thus liable to be-
come converted into vinegar ifaccess of air be not
prevented; for if air be present, the gluten absorbs
oxygen and becomes- insoluble, and‘ its oxidation is
communicated to the alcohol, which is thus converted
into acetic acid. If the wine be left undisturbed in
casks with a very‘ limited access of air, and at a cool
temperature, the oxidation of the azotised matter
goes on without the alcohol undergoing the same
change, a higher temperature being required to enable
the alcohol to- combine with oxygen. So long as the
wine in the stilling casks deposits yeast, the addition
of sugar will continue the fermentation; such, how~
ever, is not the case with old well-layed‘ wine,
because a substance in the act of decomposition, such
as yeast, is no longer present in it. In hotels, and
places where wine is drawn‘ gradually from the cask,
and a proportionate quantity of air introduced, its
conversion into acetic acid is prevented by adding a
little sulphurous acid, which, combining with the oxy-
gen of the air in the cask, or which is dissolved in the
wine, prevents the oxidation of the organic substance.
The phenomena of fermentation1 may be usefully

(1) On this subject we have chiefly followed Liebig’s views, as
expounded in his “ Chemistry applied to Agriculture'aud Phy-
siology.” 1847. _ ,
1000
WINE.
reca'pitulated in the following form :—Grape-sugar
consists of carbon, hydrogen, and oxygen; the pre-
sence of a ferment disturbs the relative proportion of
the atoms, and leads to the production of carbonic
acid, which for the most part escapes in the form of-
gas, and alcohol, which remains in solution. The
number of atoms of carbon and oxygen is thus dimi-
nished. For example :--
Three atoms of sugar = 3 atoms hydrogen, 3 atoms
carbon, 3 atoms oxygen, decomposed ;
One atom of alcohol~= 3 atoms hydrogen, 2 atoms
carbon, 1 atom oxygen, formed;
One atom of carbonic acid = 1 atom carbon, 2 atoms
oxygen, formed.
So long as sugar is present, the power of the gluten
or ferment is exerted in converting it into alcohol:
when no sugar is left, it acts on the alcohol, and con-
verts it into vinegar by the acquisition of 1 atom of
oxygen. This action, however, is not immediate, but
is brought about by means of a substance termed
aldehyde, which consists of alcohol deprived of 2
atoms of hydrogen, the hydrogen being oxidised at
the expense of the oxygen in contact with it, water
being formed and heat evolved. The aldehyde has a
great affinity for oxygen, combines directly with it, _
and produces acetic acid. The formulae for these €
changes are thus stated in Kane’s “ Elements of
Chemistry :”--—
Grape sugar (3,, H1, 0,,
This contains exactly the ele-
ments of 4 atoms of carbonic

acid gas .............. ......... ..: C8 — O, disappears.
and.2 atoms of alcohol .... .. C, H a 0,,
The formation of acetic acid -
from alcohol consists of two
stages: 1st, the. abstraction
of hydrogen, by which alde-
hyde is formed; and 2dly,
the addition of oxygen, by
which acetic acid is pro-
duced. Alcohol C, H0 0,,
Gives by... -- H,
Aldehyde C, H, 0,,
And this gives by... + O,
Hydrated acetic acid C, H, 0,,
Or hypothetic dry acetic acid.. C, H8 0,,
The exclusion of atmospheric air from wine, its pre-
servation at 'a low temperature, and the manipula—
tions required for its maturity, are included under
the operations of melting, sulpfiurlrzg, fim'cg, mixing,
bottling, and cellarz'ng.
The careful exclusion of wine from contact with
the oxygen of the air is necessary to prevent the set-
ting in of the acetous fermentation.- When once the
vinous fermentation has begun, however limited the
supply of oxygen, it cannot be arrested so long as
any saccharine matter remains in solution. It does
in fact go‘ on, and impart those valuable properties
which ‘are so much esteemed in what is called old
mice. When the quantity of saccharine matter is
large, and that of the gluten small, the latter will be
wholly decomposed, and only a small portion of the
sugar be converted into alcohol, the remaining sugar
being in solution, and forming. the constituent of a
appeal wine. This excess of sugar will even serve as a

preservative to the wine, air being excluded. - Thus
we hear of certain sweet wines having been kept for
long periods of time. llfowzlaz'c wine, buried at the
time of the great fire of London, and taken up in the
year 1811, was found to be of superior quality; mas-
caclz'ae wine has been kept 200 years. In the prepa-
ration of such wines an excess of sugar may be added
during the first fermentation, to ensure the decompo-
' sition of the whole of the ferment. The juice of the
grapes grown in colder climates, however, which is
much less rich in saccharine matter, furnishes a wine
which is liable to become soon pale/reel, (that is,
affected with the first symptoms of the acetous fer-
mentation,) in which case the addition of sugar, so
far from acting as a preservative, would hasten the
mischief. The transformation of the whole of the
sugar into alcohol produces what is called a (2313/ 205126 ,-
to effect this result, the fermentation is excited from
time to time by rolling the cask, or returning the wine
to the cask to feed, as it is called. A portion of un-
decomposed gluten in the lees acts as the excitant.
In this operation care must be taken not to push the
fermentation too far, or to allow an excess of gluten
in the cask. By way of precaution, the bung-hole is
left open for some months, and the cask is frequently
filled up, so that the excess of yeast may escape
out of the cask. After this has gone on for some
time, the wine, if of good quality, is racked off into a
clean cask previously sulplmrecl; that is, just before
the wine is racked off into it, a rag steeped in sulphur
is set on fire, and introduced at the bung-hole of the
cask,-the object being to convert the whole of the
oxygen of the air of the cask into sulphurous acid,
and it is generally stated in books on the subject that
this object is completely accomplished. This, how-
ever, is a mistake, for as soon as a small portion of
sulphurous acid is generated, it forms with the remain-
ing air of the cask a mixture which will not support
combustion. The extinction of the sulphur flame,
which is a mark to the operator of the success of his
expedient, proves in fact nothing more than the ex-
istence within the cask of an atmosphere which will
not support the further combustion of sulphur, but
does not prove the complete conversion of oxygen
into sulphurous acid; for there is probably two-thirds
of the oxygen of the cask still unchanged, and still
capable of producing that action on wine which it is
the object of this process to avoid. Some persons
employ sulphate of potash, in the proportion of a.
drachm of salt to the pipe of wine, for the purpose of
absorbing oxygen. Black oxide of manganese and other
substances have been empirically recommended. In
racking 0d the wine, the upper portion or cap, and the
lower portion or lees, should be rejected: they may
be afterwards used for making brandy or vinegar ac—
cording to circumstances.
Good wines may be racked as often as three times
during the first year; but as racking does not get
rid of those particles which neither sink to the bottom
norrise to the surface, but remain suspended in the
'wine, the process of - fining is resorted to previous
to bottling. There is much empiricism connected
WINE.
1001
with this operation-a variety of powders being
recommended, which, if we are to believe their in-
ventors, would almost have the effect of converting
a bad wine into a good one. The common wine-finer
is either isinglass or white of eggs.
In order to confer firmness or rlm'ah'llitg on wines,
the process of mining is resorted to. For example, a
wine of good quality, but which, in the judgment of
an experienced wine-grower, would be liable to turn
off on keeping, has mixed with it in certain pro-
portions wine which is eminently distinguished by
its firmness, the result being a wine of medium quality
well adapted to certain markets. The mixing
of wines requires tact, skill, and judgment, and is
one of the ordinary operations of the wine-grower.
It ,is apt, however, in the case of some wine-mer-
chants or venders of wine, to degenerate into doctor‘
ing, or making up wines as physio is made up, from
various sources, according to certain recipes. The
doctoring of wines, however, is practised on a magni-
ficent scale in Portugal, where, in the port-wine
prepared for the English market, and required by
Portuguese law to be “black, sweet, and strong,”
the blackness or colour is supplied by the juice of
the elder berry, which is largely cultivated in the
wine districts for the purpose; the sweetness is
produced by checking fermentation at an early stage ;
and the strength by mixing large quantities of
brandy with the unripe wine in the cask. The addi-
tion of brandy to wines intended for the English
market is made under the pretext that the wine
would not otherwise bear the voyage: this is cer-
tainly untrue, and we have the assurance of an ex-
perienced importer of wines, that “there is no port—
wine produced that cannot be, and may not be,
shipped to any part of the world, and that will not
keep for acertain time.” Particularly delicious wines,
which are called port-wines, but the character of
which is very different from what we understand
in England by that name, are asserted by the same
authority to be capable of being shipped to this
country, and if drunk off in draught, would keep
as they keep in their own native country, for one,
two, or three years, or if purified and bottled, would
keep as in Oporto, without a single drop of brandy, for
16 or 17 years.1 The addition of brandy to wine
injures its vinosity, or that peculiar combination of
alcohol with certain organic vegetable compounds
which renders wine, when taken with moderation,
a wholesome and a natural drink. The added brandy
does not combine with any of the constituents of the
wine, but exists in a free state, and produces those
injurious effects on the human system which are
supposed to be limited to dram-drinking.
One of the objects of mixing wines is to produce
a compound possessing qualities which do not exist
in any single wine. The mixing of Rhenish wines is
a delicate and dillicult art; but of all wines, sherry
is that which is most mixed with the vintages of
different years. The wine-merchants of Xeres always

(1) Mr. J. J. Forrester’s Evidence contained in “Report from
the Select Committee on Import Duties of Wines.” 1852.

retain in store a. quantity of old fine wine, and the
proportion in which it is mixed with newer or inferior
wines depends upon the market to which it is to
be expedited, and the price. The quantity thus
drawn oil’ from the oldest and finest casks is made
up from casks which most nearly approach them in
age and quality; and these in their turn are filled
up from casks which resemble them in similar qualities,
—-so that a cask of wine 50 years old may be made
up from the vintages of 30 or 40 seasons. After the
mixing,v fermentation is usually partially renewed in
the cask; this is called fi'etllng, and the process of
combining one wine with another is called fretting
in. Fermentation is sometimes excited by rolling or
agitating the cask. The processes of lining and
racking are repeated in order to get rid of ferment
and colouring matter, the presence of which might
endanger the durability of the wine, and injure its
appearance. The wine is now left in the cask, or in
the woorl, as it is termed, to mature. The time re—
quired for this important effect is variable. It is
greatly assisted by an elevation of temperature; and it
is not uncommon to send wines, such as sherry and
Madeira, on a voyage to a warm climate, and to leave
them there until maturity has been obtained. In
Madeira the wine-stores are often situated in the top
floor of a house, in order to have the benefit of the
sun’s rays, and it is not unusual to send the wine
to this country by way of the West Inches. While
the wine is in the wood, a considerable portion of its
watery contents evaporates, and there is some loss
from ullage. The amount of loss from evaporation
varies with the climate, and the kind of wood of
which the cask is made. The loss sometimes amounts
to one-twelfth per cent. per annum, as is the case
with wines contained in casks of Spanish chest-
nut, which is an objectionable wood on account of
the taste which it imparts to the wine. Memel or
Dantzig oak is used for port‘wines. The ullage is
greatest in new casks, and hence old ones are pre-
ferred, provided they are sound and sweet. As the
watery particles evaporate, matters which they held
in solution are deposited, in consequence of their
insolubility in alcohol. These form what is called
tartar, which consists of an impure bi-tartrate of
potash and other substances. The colour changes;
that of red wines generally becoming deeper, as in
the case of Médoc, but some paler, as in port ; hence,
in order to give the appearance of age to port,
white port (or that from which the skins of the
grapes have been removed at an early stage of fer-
mentation, before sufficient alcohol has been generated
to dissolve out the colour) is added; and to clarets,
the black wine of Cahors is added. It has been
supposed that wine ripens better in large than in
small casks, and hence such enormous tuns as those
of Heidelberg have been constructed. The celebrated
Heidelberg tun constructed in 1751 is 36 feet long,
and 2% feet high, and is of the capacity of 800 hhds.,
or 283,200 bottles. When any of the wine is drawn
off, care is taken to fill up the casks with wine of the
same quality-and if this is not to be had, olive oil is
1002
WINE.
used—in order to prevent the contact of the oxygen
of the air with the wine, which would cause it to
degenerate into vinegar. The surface of the wine
would also soon become covered with a fungus if this
precaution were neglected. In damp cellars, the
casks are liable to become affected with dry rot,
which may thus lead to the loss of their contents.
The mouse-skin Byssus (Raeoclz'um eellure) is a fungus
which grows only in dry cellars, and is regarded as
an indication of the soundness of the casks. When
the wine has been in the wood for a certain time,
it improves in alcoholic strength and other qualities;
but if left too long, alcohol, instead of water, will
begin to evaporate: the wine is then fit for bottling.
Previous to this operation, however, the wine under-
goes fining, and it is left for 10 or 15 days to become
clear. The bottling should take place in March or
October. Bottles should be quite clean, the corks
sound and well driven in, so as to expand below the
contracted part of the neck of the bottle, and com-
pletely exclude the air. To protect the corks from
the attacks of insects, the exposed part is often
covered with a waxy composition; but the wines
themselves, especially the dearer and sweet wines,
will corrode the corks, which therefore require to
be renewed from time to time. In the case of Italian
wines in bottle, it is not unusual to omit the cork
altogether, and fill up the neck of the bottle with
olive oil. Red wine in bottle deposits a crust on the
side in contact with the sawdust of the cellar. Cham-
pagne requires to be corked twice. It is first bottled
after remaining only three years in the cask; then
corked, and the bottles placed in an inclined position,
with the necks downwards. A considerable deposit
takes place, which, when completely formed, is re-
moved by withdrawing the cork from the bottle while
in its inclined position; a portion of the wine rushes
out carrying with it the lees, the remaining clear
portion of the wine being intercepted by the operator
closing the mouth of the bottle with his fore-finger,
at the moment when the last particle of lees has
passed the neck. The bottle is then filled up with
a solution of sugar-candy in one of the ordinary
wines of the country, then corked, wired, and the
neck sometimes covered with tinfoil. In this con-
dition champagne may be kept from 10 to 20 years.
The loss of bottles by bursting, in the champagne
trade, is said to amount to from 20 to 30 per cent.
and a machine has been invented for testing their
strength, which ought to be equal to bear the
pressure of from 25 to 35 atmospheres. The peculiar
care required in the manufacture of such bottles
causes their price to be nearly double that of ordinary
bottles. In France alone, the general wine bottle
trade is estimated at above 60,000,000 of bottles an-
nually, and the value at more than half a million
sterling.
The almost endless diversity of wines is produced
by variations in the proportions and modes of combina-
tion of a comparatively small number of ingredients”J

These are water, also/ml, tenant/tie et/zer, (forming thel
Zzouguetfi) sugar, gum, cute-active or colour-lug mailer, l
luuuz'u, gluleu, certain acids, of which lurt‘urz'e is
the chief, and certain salts.
Wines which contain much alcohol are termed
strong and generous; when the proportion of alcoho.
is small, they are called lag/rt or wee/e ; when the
proportion of sugar is large, they form luscious wz'ues,
sweet wines, mus cle liqueur ; when little or no unde-
composed sugar is present, the wines are said to
be clrg; if a considerable proportion of free acid be
present, they are called acid or uceseeul wines. The
presence of carbonic acid produces spur/cling or
efiierueseeul wines, called mousseua: by the French,
and seltuumwez'ue by the Germans.
The quantity of alcohol in wines has been ascer—
tained by analysis. Many years ago, Professor
Brande instituted an extensive inquiry on this sub-
ject, the results of which are given in his “ Manual
of Chemistry.” In 1838, Professor Christison made
some experiments, some of the results of which are
given in the following table. The second table,
showing the amount of alcohol in French wines,
is by M. J. Fontenelle.




Alcohol by Proof‘ spirit
NAMis OF Wmss, 8:0. \w eight by volume
per cent. per cent.
Port, weakest 14'97 30'56
,, mean of 7 wines .. 16'20 33'91
,, strongest .. . . 17'10 37'27
White port 14'97 31'31
Sherry, weakest 13'98 30'84
,, mean of 13 wines, not long in
cask 15'37 33'59
,, strongest 16'17 35'12
,, mean of 9, long in cask in East
Indies M72 32-30
,, Madre da Xeres ................... .. 16'90 37-06
Madeira, long in cask in East Indies...... 14'09 30'80
,, strongest.............................. 16'90 37'00
Tenerifi‘e, long in cask in Calcutta .... .. 13'34 30'21
Sercial 15'45 33'6'5
Dry Lisbon .. 16'14 34'71
1295 2330
Amontillado....................................... 12'63 27'50
Claret, first growth, 1811 ................... .. 7'72 “595
Chateau-Lemur, first growth, 1825......... 7'73 17°06
Rosan, second growth, 7'61 16'74
Vin Ordinaire, Bordeaux.............. .. 3'99 13‘96
Rivesaltes....................... .. 9'31 22'35
Malmsey 12'36 23‘37
Rudesheimer, first quality . .. 8'40 13 44
,, inferior 6'90 15‘19
Hambacher, first quality 7'35 16'15
Edinburgh ale, unbottIed..................... 5'70 12‘60
,, two years bott ed ....... .. 6'06 13-40
London porter, four months in bottle 5'36 11 91
Wm'es. Aiziiliiiiieby Wuens. b'yuf,g§‘§,1ne
per cent. per cent.
Bamyulls 21'95 Meze ................ .. 18'60
Rivesaltes 21'30 Beziéres . ......... .. 18'40
Colliouvre .......... .. 21‘62 Lune1.................. 18-10
Lapalme 20'93 Montpellier 17'65
1V1irepeisse1............ 20'45 Carcassone ....... .. 17 '22
Sallces.................. 20'43 Frontignan 16-90
Narbonnes ...... ...... 19'90 Bourgogne 14 75
Leriguan............... 19'46 Bourdeaux ....... .. 14-73
Leucate (1e Fiton 19'70 Champagne ....... _. 12-20
Montagnac............ 19'30 Toulouse 11'97
Nissan.................. 18'80


WINE.
1003
Such inquiries as those which lead to the foregoing
results, lose much of their value from the fact that
the alcohol naturally produced by the fermentation of
the grape juice is increased‘ in quantity by the addi-
tion of brandy. It is a popular notion, in this coun-
try at least, that wines cannot be kept unless brandy
be added, and probably no housekeeper would think
of bottling her current or gooseberry wine without
the addition of a certain proportion of brandy. That
the practice is unnecessary is proved by the fact that
the light Rhenish wines, which will keep for a century,
are never brandied. If the causes of acetification be
present in the wine, or the wine be not properly pro-
tected from the oxygen of the air, the addition of
alcohol cannot prevent it from turning. It will be
seen by reference to ACETIC ACID, that the stronger
the liquid is in alcohol, the stronger will be the
resulting vinegar, and that the change from alcohol
to acetic acid may be brought about in a few hours.
The brandy used in the adulteration of port-wine
is distilled from the common ordinary wine, or via
orrllnaz're and _pelil vz'iz. Nine pipes of this wine pro-
duce one pipe of spirit. This brandy when old is of
very fine quality: it is very cheap,—so much so that,
in some years when the vintage is abundant, a pipe of
it has cost less than a pipe of wine grown within the
district which produced the finest wine.
The custom of adding strong spirit to wines in-
tended for the English market, may have been favoured
partly by the climate of England, partly by the love
of highly stimulating drinks among the people. At
any rate, the taste for strong ports and sherries seems
to be so confirmed, that supposing the duty on foreign
wines were reduced from 5s. 9d. to 1s. per gallon, as
has been proposed, it may reasonably be doubted
whether the light wines of the Continent would ever
come into general use. To show the extent to which
the wines of Portugal are brandied for the English
market alone, we may again refer to Mr. Forrester’s
evidence :-——
“ 87. You have said that the quantity of brandy in
a pipe of port-wine depends upon the nature of the
order for it. Now what is the minimum, and what
the maximum quantity of brandy in a pipe of port-
wine when it reaches this market?—~If the wine be
perfectly fermented, as a matter of course one-half
the proportion of spirit would be requisite; if it be
not fully fermented, then double the proportion; if it
be of the very light and simple character to which I
have before referred, hardly any is requisite.
“ 88. Will you state it in gallons ?--The minimum P
There is no port-wine, to the best of my belief,
comes to this country that has less brandy in it, that
is to say, adventitious spirit, than half an almude
(16 quart bottles), which is about three gallons to a
pipe—-but that is a very smallvper centage; indeed
the other wines, the richest of all that I have men-
tioned (viz. the jeropiga), is 33%.; percent; and the
heavy brandied rich wine, so denominated, cannot
ever contain less than from 15 to 17 gallons to each
pipe of115 gallons.”
The wine-drinker in this country cannot ever be

certain that the very large admixture of brandy made
to his wine in Spain, Portugal, or Sicily, forms the
whole. The dealer in this country not unfrequently
adds a further dose of brandy or whisky to his wine,
with the intention of imparting to it those symptoms
of age which are found in a lighter colour, and a.
lining of crust in the bottle, formed by a precipitate
of colouring matter on the addition of the raw spirit.
But how is the bouquet, which time alone produces,
to be formed without his aid? What will not art,
aided by science, accomplish? A drop or two of sul-
phuric acid, added to each bottle of wine, will in a
few hours produce a lively bouquet. The sulphuric
acid, by its action on a portion of the alcohol of the
wine, generates a small portion of sulphuric ether [see
E'rnnn] which supplies the place of the real bouquet,
produced by the conversion of the cenanthic acid into
cenanthic ether, which by the natural process requires
years for the tartaric acid to accomplish. We do
not, however, pretend toa knowledge of all the wine~
dealer’s secrets, or we might show how in this manu-_
facturing country port-wine is not excluded from the
list of manufactured goods. But we may state that
large quantities of fictitious port-wine are made up
from cider as a basis, a cheap French red wine, brandy
or whisky, sloe-j-u-ice, for the flavour of “ fine old
rough port,” logwood for the colouring matter, and
sulphuric acid for the bouquet. In this respect, as
in other matters of taste, the French are more skilful'
than the English manufacturers. It is stated, that at
the port of Cette, in France, any known wine can be-
manufactured at a very short notice, in any quantity,-
and that the imitation is very skilful. It would seem,
however, that the English are improving, in the art,
from the following anecdote related by Mr. G. R.
Porter :-——“A friend of mine who invented, some
years ago, a substitute for corks, which were madev
with India-rubber, stuffed with wool, was asked if he
could make some to resemble Champagne corks, and.
he undertook to do so, and was desired to make a.
small quantity by way of trial. Two days after he.
had sent them in he had a note from the parties re-
questing to see him; he accordingly went, and they
produced a bottle of this quasi Champagne wine, with.
the comment that it was in excellent order; he found
it very palatable; but he could not make out how the
corks which he had supplied to them only two days
before, could possibly have been used for the corking.
of Champagne wine, and there can be no doubt it.
must have been all made in this country.” We are
satisfied that little or no improvement will take place
in the wine trade of this country—at least so far as
regards the supply to the middle classes—until an
improved taste arises among them, and they cease.
to consider a bottle well chalked on the outside, well
crusted within, corks deeply stained with logwood,
and an odorous, hot, and exciting liquor as neces-
sary to the credit of their cellar.
The wines of France and the Rhine are generally
contemplnously styled by the Englishman light and.
soar; but he should remember that this lightness is
one of the very qualities which ought to recommend
' 1004!
WINE.
wine. The 8 or 9 per cent. of naturally com-
bined alcohol in Rhenish wine, and an abundant bou-
quet, are sufficient gently to stimulate, and not. to in-
toxicate. Intoxication is seldom or never seen on
the Continent, while it is so frequent in the British
islands. as to constitute a national feature and a
national disgrace. And, with respect to sourness,
this is produced chiefly by the presence of tartaric
acid, which seems so to correct and qualify the alco-
hol, that it no longer .produces diseases of the liver
as our brandied wines do. The combined effect of
the ‘alcohol and tartaric acid is to exalt the digestive
functions, to increase the appetite, and improve the
health; and it is remarkable how soon English visitors
to the Continent, who at first turn with disgust from
this “ vinegar ” as they call it, not only become recon-
ciled to it, but drink it with a relish which they never
knew in the case of their accustomed port and sherry.
Of the other acids sometimes contained in wine,
malic acid is seldom found, except perhaps in the
juice of grapes grown in wet seasons. Citric acid
may be present in wine made from unripe grapes.
Oualic acid may sometimes be found; but this is
doubtful, except in the case of wine made from gar-
den rhubarb. Acetic acid is most likely to be present
in the low, poor wines of northern countries; but, as
we have already seen, is liable to be present in all
wines by contact with oxygen, especially in wine on
draught, if the consumption be small. In order to
disguise its presence in wine, a highly dangerous
poison, sugar of lead, is frequently added—a compound
which may sometimes be formed in wine in bottle,
from the presence of some of the shot used in clean-
ing the bottles. Carbonic acid is present in cham-
pagne' and sparkling wines. Tauuic acid, derived
from the seeds of the grapes, imparts to port its
roughness and astringency; it is also present in Tent,
but is concealed by the sweetness of that wine. Tar-
trate of‘ alumina and potas/t occurs in some of the
German wines. Ar‘r/ol or 6i~tartratc ofpotas/i, preci—
pitated with some of the colouring matter, is how-
ever the most common salt in wines. Some wines
contain small portions of sulphate of potash, and also
of the chlorides of sodium and potassium.
Sugar is the characteristic ingredient in sweet
wines, of which the most celebrated are the Ricesaltes,
Lauel, and Froutiguau of France; the Paaarete, Tent,
and llfalaga, of Spain; the original Malmsey, of the
Grecian Archipelago; the wine of Madeira; the Cou-
stautias; the Today, and Lacliprma C/iristi, and Mara,
of Sicily. Such wines are usually taken in small
quantities as liqueurs, and Wormwood and other bit-
ters are frequently added to them, to modify their
unwholesome efl’ect. Much of the sugar, however,
disappears with age, and some of them, such as those
of Bergerac, actually become dry wines in the course
of six months. Manufactured imitations of the vine
de liqueurs are very common, and it is difficult with
this class, as‘ with other classes of wines, to procure
them genuine in England, except from first-rate
houses and at high prices.
The wines“ of Portugal are required by law to be

arranged into four classes, for which purpose tasters
or inspectors of wine are appointed. The process of
classifying wine is thus noticed by Mr. Forrester :—
“ No sooner are the wines housed, no sooner has the
farmer to feel grateful to Providence for an abundant
harvest, than the wine companies’ tasters flock up to
the Alto Douro in a shoal, pounce down upon his
property, sample every one of his large vats, mark
and number those samples (and too often for half-a-
crown any quality of wine, in any bottle, might be
substituted. for those samples); and then the tasters
arecongregated in a large room, where smoking and
other little amusements of the kind, if not permitted,
are certainly tolerated; and there, one after the other,
the samples .are only too often submitted to the
judgment of those men, many of whom have no
knowledge whatever of wine, much less of wine five
or six weeks old.” Wine of the “first quality” is
required by law to have “body, flavour, colour, and
richness to spare :” this wine is used for doctoring
other wines. Wine of the “second quality” is re-
quired to be a beautiful, pure, simple, unloaded wine;
but as it will not serve for a doctor, or for blending
or cutting with other red wines, it is not allowed to
be shipped to this country at all, nor to any port in
Europe. Wine of the “third quality” is a simple
light wine, with little body and colour, but which is
admirably adapted for table drinking, off-draught, and
may be shipped with little or no brandy at a very
cheap rate. This is the only wine used to any extent
from royalty to the peasant in Portugal; and no
other country is allowed by law to taste this racy,
health-inspiring wine. The “fourth quality” is set
aside as refuse, and is generally used for the purposes
of distillation.
The wine-merchants of Portugal evade the law
which forbids the export of any but the so-called first
quality wine, by obtaining bil/iettes, or permits for
exportation, under cover of which they bring down
to Oporto fine wines grown by themselves, in place
of the so-styled first quality. To this species of
smuggling England is indebted for ever obtaining
anything like good port-wine.
The duties laid on wines by the Portuguese go-
vernment tend further to limit the exports to Great
Britain. “By the original law, the sum of 12 milreis
was imposed as an export duty on all wines sent to
Europe; and yet they imposed 7 per cent. addi—
tional, and a second addition of 5 per cent., with
another of 3 per cent. to pay the salaries of the
custom-house clerks, and a further addition of 10 per
cent. for the loss on government paper: the 12 mil-
reis thus swell into the sum of 15 mil. 190 reis, or
3l. 8s. 4d, instead of about 2l. 18s. These are the
duties on the wines to Great Britain and to the rest
of Europe, of which one-half is a bonus awarded for
the support and maintenance of the Royal Wine Com—
pany monopoly.” The duties to America, Asia,
Africa, and Australia, and to every country out of
Europe, are only 100 reis, or. 503., with the additional
impost of 7 per cent., and 5 per cent. as above. The
sumtotal, therefore, paid on those wines which are of
WINE.
' ‘1005
the same character as ours, is 6d. a pipe, and no
permits are requisite. The Americans thus pay Get.
for the pipe of wine, while the British subject pays
imposts and duties to the amount of 6t. per pipe,
before the wine is allowed to leave Portugal. The
system of hilhettes is connived at by the government,
and they are bought and sold in the market like
shares or railway scrip.
The taste for sweet wines is in some cases pecu-
liar, a particular kind of wine being sometimes manu-
factured for a particular district or country. Thus the
Portuguese prepare for America a compound called
Jeropz‘ga: it consists of two-thirds must or grape-
juice, and one-third spirit (distilled from port-wine,
and 20 per cent. above British proof), together with
sweetening matters of various kinds, and elderberry
juice for imparting a dark colour. This mixture is
largely used in America for making negus, and sells
at double the price of wine; being very sweet, very
strong, and highly coloured, nothing more is required
for negus than the addition of hot water. Jeropiga
is also employed in Portugal for “ bringing up charac-
ter” in port-wines.
The wines of Spain are much less fettered by
Government restrictions than those of Portugal. The
Government allows bottles to be imported, for the
purpose of being filled with wine for exportation.
Casks and staves are also freely admitted, to supply
the defective cooperage of the country. The absence
of roads, and the difficulties of transport, nullify to
a great extent the natural advantages of this fine
country. There are many pure and beautiful wines
which can only be removed from the places of their
growth in skins on the backs of mules; and as the
skins impart an unpleasant taste to the wine, this
method of transit cannot be adopted.
In cases where roads have been formed, the traflic
is so badly organised that those who conduct it are in
the habit of tapping the casks, drawing off considerable
quantities of wine, and filling up the casks with water.
It is to be hoped that the system of railroads, which
is being slowly introduced into Spain, will facilitate the
transit of wine and other products. The Cadiz wine
district comprises upwards of 25,000 acres, and in-
cludes Xeres, Port St. Mary’s, Tribugena, San Lucar
di Barrameda, Chipiona, Beta, and Puerto Real. The
soil of the higher ground close to Xeres de la Frontera
is composed of carbonate of lime, magnesia, and clay,
and produces the very best quality of wine. There
is also an iron-ochre soil, which produces a fine wine
of a coarser nature. There is likewise an alluvial
soil, and lastly a sandy soil, which produces from five
to six butts to the acre; the superior soil not more
than three ; taking the average, it would give about
four butts an acre. On the whole, there would be
about 120,000 butts a—year produced in the district.
It appears from the evidence of Dr. German, that many
years ago Spain shipped her wines to this country
the second and third year after the vintage, when
the wine had been perfectly fermented, and properly
cleared of all vegetable and fermenting matter; so
that sherry came into Great Britain in a more natural

state than at present. The demand for this wine
increasing beyond the supply, recourse was had to
the produce of other districts to mix with their
wines. If there were a taste for natural wines in
England, Spain alone could supply hundreds of
thousands of butts of choice wines not yet known
in the market. In Spain, as in Portugal, the wine
is doctored to suit the English taste. The genuine
wine of Xeres is carefully fermented, and in the
spring following, the vintage is racked from the lees,
brought into the town, and placed in casks in a
cellar, where it remains for years. This pure wine
never reaches Great Britain, because the exporter
confines his operations to the instructions of the
English wine-merchant, who transmits an order for
twenty or thirty butts of wine to be prepared in
a certain way, and to have a particular taste, flavour,
and colour. The cellars above-mentioned are each
under the care of a captain or head man, who classes
the wines, and puts arbitrary marks upon casks,
according to their quality. In the course of the
year, he frequently inspects the wine, and often re-
verses his own marks, from a new development of
its "quality; some casks progressing more rapidly
to maturity than others, from their position in the
cellar, or from the quantity of natural alcohol or
saccharine matter which the wine contains. The
arbitrary marks to distinguish the fine qualities are
triple, double, and single Palma, and so on, running
over 10 or 12 numbers. ' Exporters regret that they
are'obliged to make a compound article, to suit the
artificial taste of the English market.
The quantity of alcohol which all good sherry wines
contain is about 12 per cent. The strength of the
mixed wine depends upon the quantity of brandy
which the exporter thinks it necessary to add. This
is sometimes, in the case of inferior wines, as much
as 6 or 8 gallons of Catalonian brandy to a butt
(108 imperial gallons) of wine. This is more neces-
sary in the case of wines of inferior quality than in
others, because such wines contain a large quantity
of vegetable matter in solution, and do not usually
contain more than 8 or 9 per cent. of natural alcohol.
Much of the wine grown in the Xeres district is
conveyed into the Bay of Cadiz, and there mixed
with inferior wines, and shipped off as sherries.
These inferior wines are brought from various parts
of Spain, for the express purpose of being mixed
with sherries at a place called the Aguada, in Cadiz.
Speaking of Manzanz'lla wine, which appears to
derive its name from the Spanish for camomile,
Dr. German 'states that it is produced in the sherry
district, in a soil which is a favourable mixture of
the alluvial, sandy, and albarz'za, or carbonate of lime,
magnesia, and clay. The species of vine planted
there is also favourable, producing a wine full of
flavour, and which comes in early. It is a wine
that admits of no admixture; and though it is of light
body—as light looking as water—yet if perfectly
fermented, it will endure for thirty years. It is a
genuine wine, and has a fragrant aroma, and a kind
of sub-bitter taste. It is stated that this wine may
1006 WINE.
with the exception of Cape wine, on which a duty of
2s. 8d. per gallon is paid. The following table shows
be drunk by those who have organic affections, or
great irritability with an inflammatory tendency, with
impunity, if not with advantage. the annual average quantities of wine in gallons on
The present consumption of foreign wines in Great which duty was paid, and the yearly average amount
Britain is about 6,000,000 gallons per annum, on which received at the different rates of duty, in periods from
a uniform rate of duty of 5s. 9d. per gallon is paid,
18141 to 18419 :—-~






It has been proposed to reduce the import duty on
wines from 5s. 9d. to 1s. per gallon. Those who sup-
port this reduction imagine that a taste for the pure
and light wines of the Continent would soon become
so general among the middle classes of this country,
as to compensate for any loss of revenue which might
attend the first reduction of the duty. We do not
expect that so desirable a result would be attained.
In our cold and uncertain climate, the taste is so
common for more potent drinks than the light wines
of France and Germany, that the brandied wines of
Spain and Portugal must, we think, continue to be
favoured. But it is argued that a large section of
the middle classes who now consume no wine at all,
and those even who are habitual water drinkers,
would, if they could procure a pure wine at the low
rate of Is. per bottle, drink it habitually. This, how-
ever, is a mere assumption, and is not warranted by
the fact that such persons, in their rare visits to the
Continent, consume and enjoy the light wines of the
country; they also enjoy the various strange dishes
which are set before them, but they do not on that
account, on their return to England, adopt the French
or German euz'sz'ue ,- and we think it might be doubted
whether, if they had the choice, they would exchange
their porter and ale, their port, sherry, and grog, for
the wines of Bordeaux or of the Rhine.
It is, however, certain that a high rate of duty is
disadvantageous to the country which produces, as
well as to that which proposes to receive any article
of commerce. If wine be the surplus produce of the
south of France, and manufactured goods the surplus
produce of England, it is of great importance to ex-
change one for the other as extensively as possible;
but this exchange will be limited in proportion as the
rates of duty levied by either country are high. In
his evidence before the Committee on Wine Duties,


1814-—1824- 1825—1830. 1831—1839. 1840-1849. 1850. 1851.
113W’. K Gallons. Ruiz‘. Gallons. ‘Bug’ Gall one. 2M2 ‘Gallons. liutzi Gallons. Gallons.
French......... 13 9 177,000 7 3 379,000 5 6 315,000 5 9 379,000 5 9 354,000 5 9 365,000
Portugal .... .. 9 1?,- 2,657,000 4 10 3,185,000 5 6 2,749,000 5 9 2,456,000 5 9 2,719,000 5 9 2,891,000
Spanish ...... .. 9 1} 986,000 4: 10 1,917,000 5 6 2.296,000 5 9 2,437,000 5 9 2,558,000 5 9 2,587,000
Madeira 9 2% 325,000 4 10 279,000 5 6 143,000 5 9 91,000 5 9 87,000 5 9 82,000
Azores......... 9 1%; 4,000 i 10 5,000 5 6 1,000 5 9 178 5 9 67 5 9 245
Canary ....... .. 9 1}; 156,000 é 10 132,000 5 6 57,000 5 9 22,000 5 9 20,000 5 9 16,000
Rhenish ...... .. 11 3% 22,000 4 10 80,000 5 6 51,000 5 9 54,000 5 9 48,000 5 9 56,000
OTHER SORTS.
Marsala, 850... 9 1k : 62,000 4 10 175,000 5 6 354,000 5 9 447,000 5 9 457,000 5 9 437,000
Cape............. 3 01} 440,000 2 5 627,000 2 9 529,000 2 10i- 3‘H,000 2 101} 241,000 2 10% 246,000
1814 to 1824 Duty average £2,125,050 Number of gallons 4,832,789
1825 to 1830 — 1,613,064 ............. .. —— 6,784,802
1831 to 1839 —- 1,700,589 “um-m...- -—- 6,497,550
1840 to 1819 ............... -- 1,746,002 ............... -- 6,238,044:
Mr. Gassiot reviews the effect of raising or lowering
the duty on wine. From the year 1814'.‘ to 1824, we
had differential high duties, French wine being at
13s. 9cl. per gallon; Rhenish wine, 118. 362.; other
wines, 9s. 1cl.; and Cape wine, 3s. In 1825, the duties
were considerably reduced; French wine being re—
duced to 7 s. 3%, and all other wines, except Cape, to
as. 10zl.; the Cape wine was reduced to 2s. 5d. In
1830 or 1831, the duties were assimilated to 5s. 6:1.
on all wines except Cape, which was at 2s. 905. In
1839 or 1840, the duty was increased by an aul vu—
lorem of 5 per cent. It will be seen by reference to
the foregoing table, that an increased rate of duty
diminished the consumption of wine, while a low rate
of duty considerably increased it.
In order that the revenue may not suffer loss by
the proposed reduction of duty from 5.9. 96l. to 1s.
per gallon, it would be necessary that the annual
average consumption of 6,000,000 gallons should be
increased to 30,000,000 gallons. It is not likely that
so large an increase would occur, and should it do
so, doubts have been expressed as to the capabilities
of the wine-growing countries to supply the increased
demand. Those, however, who are well acquainted
with the wine-growing districts of France, incline
to the opinion that the banks of the Rhone would
alone supply it. Mr. Tuke states that from Cette
alone we could easily draw 50,000 pipes; from Port
Vendres, 10,000 pipes of a wine particularly qualified
for this country, and that Marseilles would supply
any quantity required. In the neighbourhood of the
Rhone, there are vast tracts of land capable of pro-
ducing fine wines, which are now uncultivated in
consequence of the limited demand; and it is stated
that if a demand sprang up in this country four hun-
dred times greater than it is now, that demand could
be met by increased cultivation.
WINE.
1007
These remarks apply to ordinary wines of fair qua-
lity, but it must he understood that the supply of the
finest wines will always be limited. The finest ports
are obtained from a comparatively small district of the
Douro. The vineyards in the immediate vicinity of
Xeres alone produce the finest sherries; the finest
elarets are grown in the small district of Médoe, as
already noticed; and there is only one small valley in
the island of Madeira where the finest malmsey can
be produced. The people of England are so accus-
tomed to drink wine under the name of port or sherry,
that the attempts to introduce other red wines and
white wines as substitutes, under their own proper
names, have completely failed. One witness, who has
tried the experiment in the case of red wines, says,
‘-‘ Neither lllasdeu, Fz'yuez'm, nor the red Sicilian wines,
however low the price may be, will ever come into
competition with genuine port—wine.” Large quan-
tities of red wine are, however, introduced and passed
off as port. Mr. Tuke says that he has sold red wine
from Marseilles, particularly from one soil, under the
name of Baudole, at 35s. per hogshead on board, which
has come to this country and has been consumed, and
has reappeared, no doubt, under the name of port, as
he has not seen it since it left his hands. Contracts
for wine have lately been made by the same gentle-
man at 4s. a dozen, z‘. a. 4d. a bottle, (including cases,
bottles, and corks,) which wine came to Liverpool,
and is described as a fair sample, and wine that would
stand any voyage: it was destined for African con-
sumption. It is a common practice, in the decks of
the port of London, to introduce red wines from
France and elsewhere, to mix them with wine from
Oporto, to pay duty on them as “ports,” and send
them out to the public as such. Thus the comptroller
of accounts in the London Docks, on being examined
before the Committee of the House of Commons
already referred to, admitted that if 1,000 casks of
port—wine were exported from Cette to New York,
and then brought to London as port-wine, it would
be at once mixed with the port-wine of Oporto, and
called port. In this way 20,000 casks of wine from
Oporto may become 60,000 casks for the use of the
consumer. French wines have also been shipped from
London to Jersey or Guernsey, and then brought back
as port-wines.‘1

(l) The "Association for the Prevention of Frauds in the Wine
and Spirit Trade,” attempted in 1851 to put a stop to this prac-
tice, as the following memorial will show :—
“To the Honourable the Commissioners of her Majesty's
Customs for the Port of London, the Memorial of the Committee
of the Wine and Spirit Association, London, showeth, that it
has come to the knowledge or your memorialists that wine of
various descriptions, viz. Spanish red wine, French, Tenerifi‘e,
Marsala, with sometimes a small quantity of port wine, and in
some instances none, have been blended together in the public
warehouses in London, and in foreign parts, shipped to Guernsey
and other places, and immediately imported as port wine. Your
memorialists have no desire to interfere with the legitimate
freedom of trade, nor to deprive the public of the enjoyment of
such mixtures if they require them; but they have always con—
sidered it their duty, both to their constituents and the public,
to prevent by all means in their power every description of
fraud, and are convinced that in so doing they will receive the
support of your Honourable Board. The blending having, as they
are informed, been done with your sanction, they do not pre-

The abundance and cheapness of wine in many
parts of the Continent “are indeed surprising to an
Englishmamwho obtains a scanty supply at a high rate,
and often of bad quality. Fiscal regulations interfere
to prevent the overflowing with wine from being a
blessing, as it was in the days of old. Many a wine—
growing district would gladly exchange its abundance
of wine for our manufactured products, could the re-
spective governments only consent to the interchange.
Wine that would gladden us is often thrown away or
merely given away, from its very abundance. The
produce of wine in France alone is estimated at
800,000,000 of gallons per annum, the average value
of whichis about 7d. per gallon. Of this quantity
however, according to Lenoir, one-sixth is of good
quality, one-sixth passable, one-sixth drinkable, and
three-sixths varying from bad to detestable. The bad
wines, and the wines of very abundant harvests, are
distilled, the quantity amounting to about 110,000,000
gallons. The quantity of wine exported from France
to Great Britain is only 400,000 gallons, and the whole
of the French exports throughout the world does not
exceed 24,000,000 gallons. The home consumption
is therefore very large, amounting, in fact, to the
consumption of beer in Great Britain, or about 20
gallons per head per annum. In Paris alone, where
the wine is subject to an octroi duty, the consumption
averages 216 bottles per head per annum of the po-
pulation.
Con-siderable changes have taken place in the taste
for wine among the educated classes of Great Britain
for some years past. Not only is less wine drunk, but,
as Mr. Shaw observes, “a decided change for purer
and less brandied wine is taking place ; the causes of
which are—1. The numbers who now visit the Conti-
nent; and no one can do so for even a month without
finding all our wines, scarcely excepting our claret
and other kinds from France, disagrceably heavy and
loaded. 2. The fear of every one, with any regard for
his character, lest he should appear intoxicated—a
great contrast to times not long past. 3. That in-
stead of dining as formerly about five o’eloek, and
remaining many hours at table, the usual dinner-hour
is about half-past six and later. The fact of much
a more white wine being drunk during dinner, and the
abandonment of the habit of sitting for any length of
time after it, are showing moreover their effects on
the consumption of port. This old custom is pecu-
liar to ourselves, and, like other singularities of indi-
viduals and nations, is falling before civilization and

sume to make any comment upon it; but they are perfectly
certain that the use made of it cannot have received your appro-
bation, and they beg leave, therefore, respectfully to suggest
that, for the purpose of preventing the repetition of such use,
all wine not imported direct from the place of its growth, shall
be admitted to entry only as ‘red’ or ‘white’ wine, as the
case may be, but not allowed to be described as the produce of
any particular country, unless accompanied with a satisfactory
certificate of origin. And your memorialists will every pray, &c.”
In answer to this memorial, it was stated by the Custom-house
authorities that the plan proposed would not prevent the fraud,
but only render it a little more diflicult, “as the wine would
still be mixed at Guernsey or I-Iamburgh, and imported as at
present under the denomination of Port or any other name which
it might serve the importer to give it.”
1008
WINE.
the influence produced by greater intercourse with
others. Another cause still, which bears both upon
the quantity and quality of the wine consumed, arises
from the comparatively little party and political ani-
mosity which now exists, but which formerly led to
much drinking ; and a great change is also attribu—
table to a higher tone of manners and of conversation,
making discussions on what we eat and drink compa‘
ratively rare. Neither would it be fair to those ex-
cellent advocates of abstinence from all intoxicating
liquors, to omit alluding to the beneficial effect of
their labours.
“ There is no country in the world where drunken-
ness, and the crimes necessarily arising from it, pre-
vail to any such extent as among ourselves; for,
indeed, the consumption of spirits is nearly a gallon
yearly for every man, woman, and child, which, in-
dependent of large quantities illicitly made and
smuggled, is four times the quantity and five times
the revenue from wine. It would not be difficult to
show the terrible evils and expenses which this curse
of our country entails, but it is not by increasing
the difliculty of procuring spirits that the evil can be
remedied. The true method is to place within the
reach of all a wholesome, cheering beverage, which
wine is in its pure unadulterated state. And let me
here remark, that in no work descriptive of the habits
of our own or of ‘other countries, before the begin-
ning of the last century, do we find allusion to the
use of spirits; neither among their numerous strange
compounds do the ancients appear to have drunk
them. It will invariably be found that whenever the
choice and taste have not been fettered and forced, as
has been the case with us, a pure unsophisticated
quality is preferred, even in the northern latitudes,
to the strong heavy kinds in use here. Even in the
comparatively cold climates of Scotland and Ireland,
claret was the wine invariably drunk, and so it con-
tinued until a much later period than in England, as
in the former countries the facilities for smuggling
enabled the importation of cargoes thereof long afterjt
had been suppressed in England. Here also, however,
little else than French wines were used, until, owing
to the violent feelings roused against France about
the period of our revolution in 1688, the duty on her
wines was raised, during the thirty years from 1677
to 1707, 1,600 per cent. (from Ad. to 5s. 3d. per
gallon), continuing for many years at 138., and being
actually raised in 1813 to 19s. 8d. per gallon, or
39s. 4d. per dozen. The consequence has been that
excepting in 1825, when the duty was lowered from
138. 9d. to 7s. 3d. per gallon, the consumption never
exceeded 500,000 gallons, having been previously
less ; and even last year, including all the cheap red
wines and champagne, it was only 44,17,559 gallons,
about a fourteenth part of the whole consumption”,
Mr. Shaw states that he knows a tavern out of the
barriers of Paris, where more than half that quantity
is drawn ofl’ yearly at 3d. per bottle, and though fre-
quented by the lowest classes, a drunken person is
rarely seen. By reducing the rate of duty to Is. per
gallon, it will still be ‘from 50 to 100 per cent. on

much that would be imported, and a higher rate
would prevent that full expansion of the trade which
cheapness alone can produce. “Another most im-
portant benefit that would be derived from this rate
is the very large saving which might then be effected
in the customs, since wine being now the only article
which receives drawback on exportation after leaving
the custody of the revenue-officers, this might also
be abolished if the duty were only 1.9. per gallon, or
2s. per dozen, and the Customs system be thereby
much simplified, and numerous frauds prevented. In
reducing the duty, there ought to be no distinction of
countries; all should be put upon the same footing,
whether they act reciprocally towards us or not. Our
business is to let every country send us what we
consider best and cheapest; and if they would give.
us their wines or other things for nothing, it would
be all the better for us. The most difficult point
connected with this question is the return on stocks
in hand. Taking the amount of duty-paid stock in
wine-merchants’ cellars as equal to the quantities
cleared from bond during three years, the amount of
duty invested is about 5,500,000l., and supposing
the rate to be lowered to Is. per gallon, the claim for
return, or repayments for the difference, would be
about 4:,6CC,OOCZ., but this is perhaps too high an
estimate. It is probably no exaggeration to assert,
that nine out of every ten wine merchants are op-
posed to a considerable reduction of duty, believing
it would lower profits and prices, and open the trade
to every one, making wine as commonly sold as tea,
sugar, or beer.” It appears from official documents
that from 1791 to 1800, a population of 141,500,000
averaged 6,513,019 gallons, yielding 1,1l12,820l.;
while during the last year 27,309,3416 consumed
6,280,587 gallons, producing 1,777,259l. As, how-
ever, hard drinking was the custom and fashion of
the former period, we shall arrive at a more correct
basis by taking the means of expenditure, rather
than the number of the people. We have no means
of estimating the value of accumulated property when
the tax upon incomes was imposed in 1812 ; but this
was rated at 21,000,000l., and is calculated to have
been 15,000,000l. in 1800, and last year the amount
laid upon the same sources was nearly 60,000,000l.
Taking then 6,513,019 gallons as the consumption of
1800, at which time, with the exception of French,
which did not then form 2 per cent. of the whole,
the duty was very similar to the present rate, it fol-
lows that if the consumption had continued in the
same ratio to the means of expenditure, the annual
quantity, even at the present high 'rate of duty,
would now be 26,052,076 gallons, giving 7,493,620l.
of revenue; and this quantity, large as it seems,
(being a great contrast to our present one bottle and
and a fraction,) would be less than six bottles yearly
to each person; while, in highly taxed Paris, ‘the
proportion is 216 bottles. If we had wine as cheap
as the Parisians, although it might be long before we
should average 216 bottles, it may surely be assumed
that during the. very first year of cheapness we
should reach twelve bottles, or two gallons, which,
WINE—--WIRE.
1009
with our present population, would be 54,618,692
gallons, producing, at 18. per gallon, a revenue of
2,730,934L, being an increase of 953,675Z. Exclud-
ing port, the price of which, as I have shown, is arti-
ficially kept up, I have no hesitation in asserting that
the present rate of 5s. 90?. is a higher per centage
on the value of the great proportion of wines now
taken out of bond, than 88. would have been twenty
years ago; for in order to counteract as much as pos—
sible the enormous duty, and to meet the demand
for ‘cheapness’ experienced in every other article
on which the duty has been abolished, or greatly
diminished, recourse is had to very inferior descrip-
tions, making the duty very often 200 per cent. on
the cost.” 1
An account of the quantity of wine retained for
home consumption in the United Kingdom, in each
of the years 1849, 1850, 1851 :—



The following table gives the statistics of wine for
the United Kingdom, for the year ending January
5th, 1853.




winefl- 1849. 1850. 1851.
, Gallons. Gallons Gallons.
Cape . 241,845 246,132 234,672
French..................... 331,690 340,748 447,556
Canary . 19,868 15,995 15,928
Fayal 67 246 131
Madeira 71,097 70,360 71,025
Portugal . 2,648,242 2,814,970 2,524,775
Rhenish 46,405 54,668 58,957
Spanish 2,448,107 2,469,038 2,533,384
Unenumerated ........ .. 444,541 425,056
All Sorts .... .. 6,251,862 6,437,222 6,280,653







- Upon which Retained for
- Quantities
Wines d t h E t d. h -
., ' Imvomd- 1.82..’ ,33. "p" 8 53313583‘.
.~ Gallons. Gallons, Gallons. Gallons.
Cape . 127,952 242,805 4,054 242,619
French 575,280 503,919 169,595 475,948
Portugal.............. 2,120,716 2,567,774 384,612 2,489,350
Spanishi ............. .. 3,181,835 2,738,089 865,567 2,606,857
Madeira............... 141,317 82,064 93,075 69,730
Rhenish 70,297 60,711 12,238 58,533
Canary 86,819 16,033 86,220 14,877
Faya'l 56 396 89 897
“her 489,032 402,888 145,261 887,750
Mixed in bond..... -— --— 41,306 —-
TOTAL ....... .. 6,793,304 6,614,679 1,802,017 6,346,061


Many excellent works have been published on the
subject of Wine, of which the following are a few :-—-
Henderson, “ History of Ancient and Modern Wines,”
4to, London, 1824; M‘Culloch, “ On Wine ;” Cyrus
Bedding, “ History and Description of Modern
Wines,” 3d Edition, 8vo, London, 1850; Paguierre,
“ Wines of Bordeaux,” 12mo, Edinburgh, 1828;
Jullien, “ Topographic de tous les Vignobles connus,”
3d. Edition, 1832; Brenner, “Die Deutschen Schaum-
weine;” also, “Weinbau in Siid-Deutschland ; ” and
“ Weinbau in Frankreich.”
WIRE. The malleability of certain metals was
probably discovered before their ductility, for it is
evidently a simpler process to beatv out a metal into
a thin sheet, than to form it into a rod, and gra-
dually extend its length by passing it through the

(1) Letter from Mr. Thomas George Shaw to the Editor of the
Times, April 22, 1852, handed in, in his evidence before the Far-
liamentary Committee.
VOL. II.

holes of a plate of metal harder than itself. It has
been suggested by Beckmann, that wire was first
formed by cutting up sheets of metal into thin strips,
a process actually followed in making the sacerdotal
dress of Aaron, as we read in Exodus xxxix. 3, “ And
they did beat the gold into thin plates, and cut it
into wires, to work it in the blue, and in the purple,
and in the scarlet, and in the fine linen, with cunning
work.” Wirework is but rarely mentioned in the
writings of the ancients, and in the few cases which
do occur the metal appears to have been wrought
on the anvil. In the more modern works on Tech~
nology, no mention is made of the draw-plate. In
the History of Augsburg, of the date 1351, and in that
of Nuremburg, 1360, the artists who fabricated wire
by means of the hammer are called wire-smiths ; but
as the term wire—drawer (dra/ttzielzer) also occurs
in these works, it is evident that the draw-plate
had been invented, but had not entirely superseded
the ancient method. In France, the invention is
ascribed to one Richard Archal, and iron-wire is
called in that country jil d’ArcfiaZ, and also fil ole
Ric/lard. It is stated that wire was manufactured
by hand in England until the year 1565, whenone
Christopher Schultz, a Saxon, in company with other
foreigners came to this country, under the permission
granted by Queen Elizabeth to strangers, to dig for
metallic ores, and introduced the drawing-plate. Pre-
vious to this, the supply of iron~wire, together with
the combs employed by the wool-combers, was chiefly
obtained from abroad. In the reign of Charles I. it
is stated in a proclamation that “iron-wire is a
manufacture long practised in the realm, whereby
many thousands of our subjects have long been
employed; and that English wire is made of the
toughest and best Osmond iron, a native commodity
of this kingdom, and is much better than what comes
from foreign parts, especially for making wool—cards,
without which no good cloth can be made. And
whereas complaints have been made by the wire—
drawers of this kingdom, that by reason of the great
quantities of foreign iron-wire lately imported, our
said subjects cannot be set on work; therefore we
prohibit the importation of foreign iron—wire, and
wool-cards made thereof, as also hooks and eyes, and
other manufactures made of foreign wire. Neither
shall any translate and trim up any old wool-cards,
nor sell the same at home or abroad.” The Forest
of Dean, which supplied good charcoal iron, was long
the seat of the wire-drawing trade ; but in the 17th
century, it seems to have followed the woollen cloth
manufacture into Yorkshire. Barnsley and its neigh-
bourhood were long celebrated for the manufacture
of wool-cards; but at present wire-drawing is car-
ried on throughout the manufacturing districts,
Birmingham having perhaps the largest share in the
trade.
Previous to the introduction of grooved rollers
[see IRON, Il‘ig. 1240], the rods of iron intended for
wire-drawing were hammered out to the required
size. The best iron was used for the purpose,
and was sold in rods of about the thickness of
3 'r
1010
WIRE.
the little finger, made up into bundles, and called
usleom or esa‘eom iron, or as in the proclamation of
Charles I., Osmuud or Oe'smuual iron. A further
reduction in the size of the rods was effected by
ripping or rumpllug, in a drawing machine, in which,
according to Beekmann’s description, the axle, by
means of a lever, moves a pair of pincers, that open
as they fall against the drawing-plate, lay hold of
the wire, which is guided through a hole in the
plates, shut as they are drawn back, and in that man-
ner pull the wire along with them. In the modern
process the rods are prepared for the wire—drawer
at the rolling~mill, or for some metals by casting, and
are generally about the eighth of an inch in diameter;
they are sold to the wire-drawer in coils. Cast~steel
wire for making needles is still commonly tilted to
about a quarter of an inch square, and afterwards
rounded on the anvil, previously to being passed
through the drawing-plate. , a
The coils of rods, as received by the wire-drawer,
are covered with a scale of oxide which must be
carefully removed, for which purpose the coils are
put into a large revolving cylinder containing coarse
gravel and water, the effect of the gravel being to
loosen the oxide, and of the water to remove it. In
order to reduce, or draw out the rod into a great
length of wire, a number of similar operations are
performed upon it so as to effect the object gra-
dually. The rod is first dragged forcibly through
a hole in the drawplate of somewhat _less diameter
than itself, and as the metal of the drawplate is
harder than that of the rod, it necessarily happens
that the latter gives way and becomes extended in
length, or, as Mr. Holtzapfi'el expresses it, “the sub-‘
stance of the metal is partly kept back, as in a wave,
by a narrow ridge within the draw-plate, acting as a
burnishcr.” Thisdengthened wire is again passed
through a hole smaller than itself, and thus again
elongated. The process is repeated 10, 20, or 30
times through holes gradually diminishing in diameter.-
The draw-plate should be formed of the best cast-steel,
about 6 inches in length and 112— inch in diameter, and of
a roundish form, with the exception of one flat face.
The-holes through which the wire is drawn, are formed
by punching the flat side of the plate while red-hot,
several punches gradually diminishing in size being
employed for each hole, so as to make it of a taper-
ing form ; or the holes are sometimes “ ground out from
both sides upon the same brass cone or grinder, the
sides of which vary in obliquity from 10 to 30 de—
grees, according to the metal to be drawn; for the
sake of strength, the ridge is mostly nearer to the
side on which the metal enters, and the sharp edge is
also removed by wriggling the plate upon the grinder
in order to round the inside, or in any other manner.”
To prevent the fracture of the draw-plate, it is usual
to support it against a strong perforated wrought-
iron plate.
Fig. 237 41 represents a wire-drawer’s bench, con-
taining the drawing-plate, fixed in an upright position,
and a cylinder or clruwz'uglzloc/e, the motion of which
draws the wire through the plate, and winds it upon

its rim. Motion is imparted to this block by means
of ahorizontal shaft of iron, revolving either by steam
or water power. Attached to this shaft are anumber
of mitre or bevel wheels, which drive a number of
t Wlll u 1"










l ' it ‘p


_ _ _‘._;Y\-1_‘

Fig. 2374. wrnn-naawna’s BENCH.
upright shafts, each of which contains a drawing-
bloek. Each block can be instantly stopped by
detaching it from the upright, by means of a foot-
lever. A cross at the top of the upright fits into
a corresponding cavity at the bottom of the block,
so that when the lever is pressed by the foot, the
block is simply lifted 05 the cross, and is at rest.
At the commencement of the operation, the workman
makes one end of the coil hot, and hammers it to
a point on the anvil, so as to make it pass through
a hole of the draw-plate. The end of the wire is
then grasped by a pair of tongs or forceps attached
to a chain, rope, toothed-rack, or screw, by which
the wire is drawn through the draw-plate by recti—
linear motion, until of sufiicient length to coil round
the drawing-block, which is furnished with a small
vice for the purpose of grasping the end firmly. The
forceps or nippers are similar to carpenters’ pincers
or pliers, and the handles diverge at an angle; in
some cases they are closed by a ring at the end
of a strap or chain, which slides down the handles.
The workman then lowers the block upon the upright
shaft, when the block begins to revolve and to draw
the wire through the plate, and wind it in coils
round itself. When all the wire is thus coiled, the
block is raised, the wire removed, and the workman
proceeds to draw another piece. By varying the
size of the mitre or bevel wheels, the blocks are
made to revolve at different rates of speed, so that
the thick and strong wires may move slowly, and
the speed be increased as the wire is more and more
drawn out. There are usually four rows of blocks
revolving at different speeds, the swiftest motion
reducing the wire to about No.19 or 20 on the
wire-gage. Should the wire require further re-
duction, it is passed to the currl-wz're—druwers or fine
wire-drawers (who often carry on a distinct trade),
and they reduce it to the finest numbers, in some
cases as fine as No.40, which, when formed into
very fine wire gauze, will have 120 wires each way
in an inch, thus making 14,400 wires, and as ‘many
spaces, in the square inch.
WIRE—~WOAD.
1011
After passing the wire a few times through the
draw-plate, it is not only extended in length, but its
fibres become so condensed and hardened, that it
is impossible to repeat the operation without an-
nealing the wire. For this purpose it is placed
in coils in cylindrical kilns of iron plate, each about
4 feet diameter, and 10 feet deep, with an outer
casing of fire-brick. Each kiln contains from 20 to
30 cwt. of wire, the largest coils being put in first,
and the smaller ones within them. The cylinder
is carefully closed, and a fire lighted below, so as to
heat the cylinder to redness. This being attained,
the fire is allowed to go out, and the cylinder and
wire cool gradually; 2a hours being occupied in
the whole process of heating and cooling. In the
production of very fine wire, the annealing is repeated
6 or 8 times, a smaller number being sufficient for
the stouter kinds, and charcoal iron requires less
annealing than coal or coke smelted iron. The
process of annealing produces a scale or oxide on
the surface of the wire, which must be removed
by pickling in dilute sulphuric or other acid, for
if this scale were allowed to remain, it would rapidly
corrode the draw-plate. The card wire-drawers draw
the wire from a reel contained in a tub of starch-
water or stale beer grounds, the effect of which is to
impart a clear, bright colour to the wire. It is
however not uncommon to use some lubricating
substance, to enable the wire to pass more readily
through the draw-plate ; starch-water and beer-
grounds act in this way, and for gold and silver, wax
is commonly used. In the course of wire-drawing
the holes have a tendency to become enlarged, a
defect which the workman corrects by closing them
with blows of a pointed hammer or punch around
the hole. The gage used for determining the size
of wire is noticed fully under GAGE—GAGING.
The various metals used in wire—drawing are stated
in the order of their ductility under METAL. The so-
called gold wire of Lyons is formed by exposing a
rod of copper at a red heat, to the vapour of zinc,
whereby it is externally converted into brass. Plati-
num wire may be formed of extreme tenuity, by first
encasing a platinum wire with silver, and drawing
out the compound wire as far as it can be done
without breaking, and then steeping the wire in
nitric acid, which dissolves oil’ the silver, and leaves
the platinum untouched. See PLATINUM.
Wire is mostly cylindrical in form, but draw-
plates are also made oval, half—round, square, trian-
gular, and of complex sections, for the production of
corresponding wires by the methods above described.
Pinion wire, for clocks and watches, is formed by
drawing. Copper is also drawn into a variety of
forms for fixing into blocks used in calico printing;
an endless variety of patterns may be produced in
this way; and when the pattern is composed, the
surfaces of the wires are filed smooth, and printed
from after the manner of printers’ types. [See CALICO
PRINTING, Fig. Zl07.] Music-type is also formed of
detached wires and slips of copper fixed in a block,
which is printed from. The edging of silver or gold

boxes is formed by drawing between a pair of swagc
blocks or dies of the required section, fitted into a
frame or cramp, with a side screw, so that the metal
may be gradually reduced by one pair of swage bits.
Window lead is formed in the _ylazz'er’s vice, which
combines the two principles of drawing and rolling.
The indentations in the lead for the reception of
the glass, are formed by two narrow rollers with
roughened edges, which indent the bottom of the
grooves; while the flattened sides of the lead are
formed by the usual method of drawing. Rubies
and other gems are drilled with holes conical on
both sides, and thus form draw-plates, for making
the slender silver-gilt and silver wires used in the
manufacture of gold and silver lace. The wires
are afterwards flattened, wound spirally upon silk,
and then woven into lace. Ruby holes are used
for forming the blacklead of ever-pointed pencils.
The rubies are chamfered from one side only, and
the lead is pushed through from the small side.
The wire for pendulum springs of chronometers is
sometimes drawn through a pair of flat rubies with
rounded edges. Tubes for telescopes, &c. are drawn
upon a mandrel, as described under TUBES AND
PIPES. In this case, the draw-plate, Fig. 2182, is
made with three cones instead of two, the central
cone being just equal to the wave, or the quantity of
the metal is reduced.
As the wire for ordinary purposes is sold in coils,
it requires to be straightened for use. For the softer
wires, such as the copper wire used in bell-hanging,
and the iron binding-wire used in soldering, it is suf-
ficient to fix one end and pull the other end with a
pair of pliers. Short pieces may be straightened by
being rolled between two boards. Hard-drawn and
unannealed wires, such as those used for making
pins, bird-cages, &c., are straightened, and the spring
is taken out of them by drawing them through a
riddle consisting of a board, in which are fixed pins,
sloping in opposite directions, so as to force the wire
into a slightly zigzag or serpentine course, at the
same time keeping it close to the board. The posi-
tions of the pins require to be corrected with the
hammer for wires of different diameters. In pulling
the wire through, it must not be allowed to lean sen-
sibly against the last two pins, or it will be curved
instead of straightened.
WOAD (Isatz's tincz‘orz'a), a plant used at a very
early period for the purposes of dyeing. Caesar states
that the ancient Britons were accustomed to stain
their bodies with this substance. Woad yields a sub-
stantive blue colour, of different shades, and very
durable; and it is also useful in dyeing and fixing
other colours. It was in extensive use until the in-
troduction of indigo, which affords a superior colour,
but it is still used in conjunction therewith [see
INDIGO]. Woad is extensively grown in many parts
of Europe: in the South of France it is distinguished
by the name of pastel; but it is stated that the use
of indigo has led to negligence in the cultivation of
woad; so that it is inferior now to what it was for-
merly. Woad is a biennial plant; it has a large
3T2
‘1012
WOOD.
woody root, which penetrates to some depth, and a
stem from about 3 to A feet high, and about .f, inch
in diameter, forming several branches, covered with
light-green leaves attached close to the stalk: the
leaves afford the dye colour; they are about 12 inches
long, 6 inches broad at the widest part, and terminate
in an obtuse point. The plant bears a small yellow
flower, and the seeds come to maturity in September.
It thrives best in a friable loamy soil, and furnishes
three or four crops in the course of the year, the first
crop when the stems begin to turn yellow, and the
flowers are about to appear; the other crops are
gathered at intervals of about six weeks. The average
produce per acre is about one ton; in very favourable
seasons one ton and a half may be obtained. It is
an exhausting crop to the land. The best woad is
obtained at the first two gatherings. The plant is cut
down with a scythe, collected, and washed in running
water. The leaves are then stripped off and dried in
the sun as rapidly as possible. It is next immediately
ground in a mill into a smooth paste. The liability
of woad to blacken and putrefy requires celerity in
all the operations. The paste is formed into heaps,
made smooth, and sheltered from the rain: over~these
heaps a blackish crust forms, which, if it cracks, is
immediately closed, or the woad becomes worm-eaten
and loses its strength. The heaps are opened in a
fortnight, and the crust is mixed with the interior
portions. The paste is formed in moulds into balls,
and dried upon hurdles : if dried in the sun they be-
come covered with a black crust, and if in the shade,
with a yellow one. The former is preferred by the
dealers. Good balls are heavy, and show a violet
colour within on being rubbed, In using these balls
for dyeing, they are beaten into a coarse powder,
moistened with water, and being collected in heaps,
fermentation takes place: this is carried on for 12
or more days, until at length, according to the expe-
rience of the operator, the woad is fit for the dyer.
A powder is produced in this way which furnishes
shades of a brownish colour when mixed with water,
spirits of wine, or alkaline solutions : it forms a green
stain by friction on paper. If the powder be diluted
with boiling water, and left to stand some hours
in a close vessel, having %th of newly-slacked lime
added, with stirring under a gentle heat, a fresh
fermentation occurs, a blue froth rises, and the liquor,
though appearing reddish, yet dyes woollen of a green
colour, which, like that from indigo, changes to blue
on being exposed to the air. If the plant be treated like
the indigo plant, indigo will be afforded, but in smaller
quantity. Woad greatly improves by age.
WOLFRAM. See Tunesrnlv—Tm—Inrnonuc-
roar ESSAY, p. xcvi.
WOOD. The most important application of wood
is in the building and repairing of houses and ships,
and in the construction of machinery. For this pur-
pose the larger trees, which come under the denomi-
nation of timber, are chiefly employed. Oct/e, ash, 'and
elm, of the age of twenty years and upwards, are the
principal timber trees of England, although other
trees, such as beee/i, clierry, aspeu, willow, fiorsecfiestuut,

lime, pew, &c., are commonly ranked as timber trees.
Some centuries ago, the woods and forests of Great
Britain supplied the home demand for timber, but
in the 16th century the supply began to fail, in con-
sequence of the large quantity consumed in the smelt-
ing of iron ore [see IRON]. Various acts of Parliament
were passed for limiting the consumption, and obtain-
ing a supply from abroad, in the form of staves for
casks ,and other forms. It was even attempted to
,transfer the smelting of iron to the North American
colonies, in order to prevent the waste of wood at
home; but this measure was arrested by the applica-
tion of pit-coal to the ‘purpose, as noticed under Inox,
and a further extensive economy was made when the
prejudices against pit-coal as a domestic fuel were
overcome. [See WARMING nun Vnnrrnnrron] In-
creasing population, however, led to an extensive
demand on other countries for the supply of timber,
which was met chiefly by vast pine forests on the
shores of the Baltic and northern Europe, and also
from Canada. Timber from the latter country, how-
ever, was soon found to be inferior in strength and
durability to that of the north of Europe, and fell into
disesteem among ship-builders ; hence arose the prac-
tice of introducing the words “Memel fir” in spe-
cifications for building.
The preservation of growing timber is an art of
considerable importance, and can only be said to be
cultivated in countries where timber is comparatively
scarce. When timber was abundant in Great Britain,
the right of lopping trees of their dead wood for the
purposes of fuel was not difficult to obtain. It is
stated that many of the fine old oaks in Windsor
Forest show signs of unskilful lopping and the want
of discrimination between living and dead wood. Oak
trees are commonly found in stiff clay soils, and the
accumulation of water at their roots in such a reten-
tive soil is apt to lead to premature decay, hence the
necessity of a judicious system of draining. Oaks
which spring up from falling acorns, and beech from
the mast which lies in the woods, produce finer and
more vigorous trees than those transplanted from a
nursery. Cattle should be excluded from forests, on
account of the mischief they do to the underwood.
The underwood is almost as valuable as the timber
itself, for it may be cut down every tenth year. It is
a common practice to fell such timber trees as begin
to show decay at the top, at the time of cutting the
eoppice wood, but it would evidently be preferable to
fell them when they have ceased to increase in size by
age. Should a tree not increase above two cubic feet
per annum in size, it should be felled; but it may hap-
pen that a tree may be greatly improved in value by
felling some of the neighbouring trees which obstruct
its growth. The practice of thinning out plantations
is of importance not only as affording a supply of
wood, but, by admitting an increased supply of air and
light to the remaining trees, their growth is greatly
promoted. Oaks are said to increase in size most
rapidly when about thirty years old. Forest trees
are often planted on soil that is unfit ‘for other pur»
poses, and by the annual- fall of leaves they accumu-
WOOD.
1013
late in time a certain depth of soil. Oaks are some-
times planted in hedge-rows, and thrive well, but
they greatly injure the adjacent lands, not only by
their shade, but by their roots, which spread to a
considerable distance in search of pasture, and appro-
priate much of the manure which is intended for the
field.
The transplanting of forest trees, when they have
attained their full growth, was long considered an
impracticable thing.’ Many plans had been tried
without success, and the source of failure appears to
have been the mutilations to which the tree was ex-
posed in the operation. The method adopted by .Sir
Henry Steuart is successful on account of the great
care bestowed in taking up and removing the tree.
The ground is carefully picked and dug at a consi~
derable distance from the tree, to find the extreme
points of the rootlets. This being done, a deep trench
is cut round the tree, and the bank in which the
roots lie is undermined, and the rootlets are extri-
cated, to the amount of thousands and even millions.
These, with the larger roots, are turned aside or
bundled up to make room for the workmen, but all
carefully preserved. The tree is then lashed to the
transplanting machine, which consists of a long pole
attached at right angles to a bar mounted on a pair of
wheels. The machine being brought up to the tree,
the pole is lashed to the trunk in the first instance in
a vertical position: it is then, with the assistance of
a horse and men, brought with the tree into a horizon-
tal one, and in this condition the whole tree, root and
branches entire, is wheeled away to the pit intended
for its reception, and which has been previously care-
fully prepared, and manured if necessary. A hole in
the centre of the pit is specially prepared for the tap
roots, and care is taken that while these and the ho—
rizontal roots are set deep enough in the pit to have
sufficient cover of earth, yet that they should not be
buried so deep as to lose the necessary amount of air
and moisture. ‘ The pit for the reception of trees 30
feet high is about 18 feet in diameter. The tree
being brought on the machine to the precise spot
intended, the cords which confine the top are first
unloosed, and the branches allowed to spread out in
the natural manner: two ropes are fixedto the top,
transversely to each other, to steady the tree when
placed erect :v the roots are arranged‘ so as not to be
broken by the weight of the descending mass, and on
a given signal, the men who are seated near the ex-
tremity of the pole, or among the branches, to balance
the machine, quit their positions, and the tree rises
to a vertical position. -The tree is then nicely ad-
justed, the transverse ropes are stretched to their
utmost extent, and the proper depth being regulated,
the workmen hold aside the upper roots while they
pour in the finest mould to the under-bed of roots,
and make of. this mould a bank sloping outwards,
which is firmly troddcn down, and pushed into every
hollow and vacancy-with a small blunt stake. This
forms a nucleus or retaining bank quite clear of the
great body of roots and fibres. This method- of giving
stability to the tree before any cover whatever is laid

‘ upon the upper roots is one of the great advantages
of this system, and absolutely necessary to success.
The roots, which are often from 12' to 14 feet long;
are next discntangled and stretched, or, as it were,
combed out in the most regular manner over this bank
of mould, which forms an inclined plane for their
reception, and, if well prepared, the best possible soil
for their growth. The different layers of roots are
thus gradually embedded in mould. If this plan has
been carefully carried ‘out, no props are required.‘ The
surface soil is rammed down, and sown with grass, or
the ‘turf is restored. During the first few years
rakings and top-dressings may be occasionally applied
round the tree, and will prove a great stimulus to
growth. ‘ ' ' ~' '
It may be desirable that the tree be planted in the
same position relatively to the points of the com-
pass, as before. But in the case of trees near
the coast, or in exposed situations ‘where the action
of the wind has made the growth of ‘the tree irre-
gular, a directly opposite course may be pursued.
Almost all trees are unequally balanced, 'and- show
in their tops more or less of a ‘weather side.’ This
is often a deformity, especially on the western coast.‘
It proceeds from the tendency to throw out longer
and stouter branches on the lee side, andshorter and
closer branches and spray on that from which the blast
assails them. Wherever the action of the vair is great-
est there the greatest evolution of buds appears, and
the thickest but weakest growth of boughs and spray
takes place. This difference is so remarkable, that any
one conversant with wood, can at once point out an
old tree (especially a sycamore) that has been" more,
and one that has been less exposed, at the distance of
two or three hundred yards; and in winter, when
there is no foliage to conceal the difference in the
ramification, the thing is more striking. Hence it is
one of ‘the many improven'ients effected by Sir Henry
Steuart’s method, to bring this decided tendency to
elongation of the boughs on the lee side to act‘ on the
windward or deficient side; or, in "other words, the
longest branches must be brought to face the stormy
quarter.1 4 ‘ -
The proper time for the felling of trees is that in
which the largest quantity of hard and durable wood
can be obtained as free from sap as possible. It is a
common fault to fell trees before they have attained
their maturity. If suffered to complete their growth-
they would have the heartwood of equal weight and
strength throughout, whereas in- those out’ down pre-
maturely, the centre wood alone possessestthis requi-
site, the outer concentric rings being considerably
softer. Such timber may be said to decrease-in hard-
ness and strength in arithmetical proportion as it
approaches the sap-wood. Timber is felled during the
cold months, when the natural juices are most inactive
and the tree is'in a measure dormant. But before
' the timber can be used, the juices must beget rid of
from the'eapillary vessels, or the wood will remain
.moist'or green for a considerable period, and the planks

(1) “ The Planter’s Guide,” 2d edition, 8vo. London, 1828.
10M
WOOD.
formed from it will, in a confined situation, become
stained, and then subject to decay or dry rot: these
effects are prevented by free exposure to dry air. It
is usual in the royal dock-yards to cut out the tim-
bers for ships of the required shape and dimensions
about a year before they are framed together, and the
skeleton frame is usually left another year to com
plete the seasoning. “ Other mischiefs almost as fatal
as decay also occur to unseasoned woods; round
blocks, cut out of the entire circular stem of green
wood, or the same pieces divided into quarterings,
split in the direction of the medullary rays, or radially;
also, though less frequently, upon the annual rings.
Such of the round blocks as consist of the entire sec-
tion contract pretty equally, and nearly retain their
circular form, but-those from the quarter-ings become
oval, from- their unequal shrinking. In general, woods
do not alter in any material “degree in respect to
length. Boards and flat pieces contract, however, in
width; they warp and twist, and when they are fitted
as panels into loose grooves, they shrink away from
that edge which happens to be the most slightly held;
but when restrained by nails, mortises, or other un~
yielding attachments, which do not allow them the
power of contraction, they split with irresistible force,
and the materials and labour thus improperly em-
ployed will render no useful service.” The natural
juices of the tree must be got rid of by seasoning in
order that the wood may become dry and hard. After
the tree has been lopped, barked, and roughly squared,
it is left for some time exposed to the weather, and
may be soaked in fresh running water (as some think)
with advantage, or boiled or steamed. This dilutes
and washes out the juices, and the water more readily
evaporates from the wood at a subsequent period;
and the colour of white woods is said to be improved
thereby. In this way fir timber, on its arrival at the
port of London, is commonly formed into floats on
the Thames, and allowed to remain for some time.
When removed from the water, it is left to dry the-
roughly before it is taken to the pit to be sawn:
usually it is blocked up from theground so as to have
a free circulation of air; and if it be cut into boards,
they should be piled one on the other with fillets of
wood between them, or laid in a triangular form, with
their’ ends alternating so as to allow the air to have
free access to them. Thin pieces will_be seasoned in
about a-year, but thick wood requires two or three
year's before it is removed into the house to complete
the drying. The warm air of - a stove-heated room
will then act upon it with benefit. In the stacking
of timber for the purpose of seasoning, the pile should
be so far raised from the ground as to allow the air
to circulate below, as well as around and through it ;
and if not sheltered from the rain, care should be
taken to prevent the wet from lodging in any part.
It is now usual~in our dockyards’ to have elevated
supports of iron or of stbne'for the stacking of tim-
her, and ships are now built under covered sheds.
The drying of timber should be gradual, for if rapid,
it suffers a loss in toughness as well as in pliability:
the pores at and near the surface become contracted,

and prevent the interior moisture from escaping.
Plans for the more rapid drying of timber by means
of kilns have, however, been tried, as in Price’s patent,
in which timber destined for building purposes is
placed in a room, into the lower part of which hot
and dry air is introduced, and this, charged with the
moisture of the timber, is allowed to escape at the
upper part. By this plan timber can be seasoned in
one-third of the time required in the open air. Oak
loses nearly two-fifths of its weight by proper season-
ing. The timber should be dry before it is cut into
planks, or they will be liable to warp and shrink.
The presence of air, light, and moisture seems to
be necessary to the re-vegetation of timber or the
growth of that fungus which leads to its-destruction.
Mr. Fincham of her Majesty’s doekyard bored-a hole
in one of the timbers of an old ship built of oak, the
wood being sound, and in 24: hours the admission of
air caused the hole to be lined with a white mouldi-
ness due to the growth of a peculiar fungus, which
some time after became so compact as to admit of
being withdrawn like a stick. Cracks or splits in
timber would therefore predispose it to decay in damp
situations by admitting the air. There are great dif
ferences in woods as to their power of resisting decay;
some perish in a year or two, others are sound and
even fragrant for centuries. Teak has been found to
last six or seven times as long as oak when used in
greenhouses, as boxes for growing plants, the latter
wood not existing more than two or three years ; but
the moist atmosphere, light and heat of a greenhouse
form a severe trial for any wood.
Organic matter, such as timber or dead wood, which
contains nitrogen, is readily acted upon by moisture
and varying degrees of temperature. For the nitro-
gen, not having any strong affinity for the other ele—
ments of the wood, facilitates decomposition or decay,
and when this has once commenced, the germs of
cryptogamous plants, which had probably been depo_
sited in the living structure by the circulating sap,
become rapidly developed, and powerfully assist the
action of the other causes of eremacausz's or slow de-
cay. The fungus, which is chiefly associated with what
is called dry rot, is known to botanists as the Mem-
Zz'as laclzrymrms ; it insinuates itself between the woody
fibres, spreads rapidly, and soon leads to the destruc-
tion of the wood. These microscopic plants do not
grow in situations exposed to currents of dry air, light,
and warmth, agents which are advantageously em-
ployed in the seasoning and subsequent preservation
of wood. The preservation of the surface by means
of paints is valuable only when the seasoning has
been perfect; for, if applied without this condition,
paint acts with mischievous effect in preventing the
escaped the natural juices. Many plans, however,
have been proposed for the preservation of timber by
impregnating it with the solutions of certain metallic
.salts. - The process of Kymzz'zirzg (patented by Mr.
Kyan in 1832) consists in steeping the wood in a so-
lution of bichloride of mercury or corrosive sublimate.
It was supposed that the preservative effect was due
to the decomposition of the salt (HgOh) on coming in


ILTL—Z ; ___.


woon.
1015
contact with the albumen of firewood, whereby one
equivalent of chlorine was evolved, and the salt, now
converted into protochloride ‘of mercury, or calomel
(HgCl), formed an insoluble compound with the albu-
men, and prevented, or at least greatly checked its
tendency to decomposition. Liebig is of opinion that
the corrosive sublimate combines, not with the albu-
men, but with the‘ lignin or woody fibre. However
this may be, ‘a portion at least of the corrosive subli-
mate must» escape decomposition and even combina-
tion, for it' has been detected by chemical tests to
a depth of Jg-th to éth of an inch in various woods, and
by electrical tests even deeper: it is said to penetrate
fir to a less depth than other woods. Kyanized wood
has less specific weight and flexibility than ordinary
timber, but it is more brittle.
The success of Mr. Kyan’s process has been dis—
puted, and this has led to the employment of other
solutions. Sir William Burnet has put forward the
claims of chloride of zinc as a preserving agent, not
only for timber, but also (as with Kyan’s process) for
canvas, cordage, 850. Oil of tar, and other bituminous
matters containing kreosote ; a crude solution of ace-
tate of iron, commonly called pyrolignite of iron, with
kreosote in solution; and gas—tar free from ammonia,
have all been proposed for the preservation of timber,
as in Mr. J. Bethell’s process. It is stated that
wood, preserved by exposure to the vapour of kreo-
sote, becomes so hard as to be worked with difficulty.
The importance of oil as a preservative of timber has
long been~known. Thetimber of whalers and other
ships engaged in the oil trade last much longer, and
are less subject to decay of any kind, than those of
other ships. The staves of old tallow casks make a
more durable fence than any kind of wood which has
not been impregnated with oil. Sulphate of iron has
also been used, as in Payne’s process, (patented 18%,)
a brief description of which will explain, in a general
way, ‘the operations practised for this kind of work.
Several pieces of timber are arranged side by side on a
sledge, bound together by hoops and chains, and thus
introduced upon a railway into a long cylindrical iron
vessel, the cover or end of which is then screwed on air-
tight. Steam is now admitted, first to drive out the air,
through a valve opened for the purpose, and then to
form a vacuum, which partially occurs’ when a little
of the cold solution of sulphate of iron is pumped into
the vessel, by means of the steam-engine, to condense
the steam ; the vacuum is then completed by an air‘
pump, the liquid flows in as the air is exhausted, and
is ultimately subjected to pressure by force—pumps
also worked by the steam-engine 5 this fills the pores
of the wood with sulphate of iron. After afew minutes
the sulphate is allowed to flow out of the tank‘ by the
re-admission of air, the vessel‘ is again heated with
steam, and is similarly filled with murz'uie (J lime. A
double decomposition occursrzeillu'u lire pores of fire
wood, as the muriatic acid goes over to the iron, form-
ing muriate of iron, and the- sulphuric acid proceeds
to the lime, forming sulphate of lime or gypsum; the
latter remains principallyin the pores, whilst the mu-
,riate of iron pervades the wood generally. ‘The entire
’
process of preparing the timber, including the filling,
and emptying of the tank, requires from one to three
hours, according to the size of the cylinder. The
wood becomes much heavier, indisposed to decay, less
combustible, darker in colour, and also proof against
rot and the ravages of insects. By certain variations .
of the process, and the employment of some other
salts, the light-coloured English woods may be stained
in a variegated manner throughout their substance,
so as to be used for ornamental furniture, but the
principal application hitherto made of the process is
for preparing timber for railway purposes, and for
building, especially the wood used in piles and wet
foundations.
In addition to timber-trees, a vast variety of woods
are used for ornamental purposes. In a series of
papers contributed by Professor Forbes to the Arl
Jouruul, on “ Woods used for Ornament and Purposes
of Art,” some clear distinctions, definitions, and de-
scriptions are given, which are here, with the permis-
sion of the publisher, abridged for the profit of the
reader.
The term woorl is commonly applied to those por-
tions of the vegetable axis that are suiiiciently hard
to offer considerable resistance and solidity, so as to
be used for purposes requiring various degrees of
firmness and strength. Every flowering plant is com-
posed of an axis, and the appendages of the axis;-
the former consisting of the stem and root, the latter
of the leaves and flowers. In trees, shrubs, and
under—shrubs, the axis is said to be woody; in herbs it
is termed herbaceous. In the former .the stems are
permanent, and do not die to the ground annually, as
is the habit of the latter. A shrub, a tree, an under-
shrub, a bush, are merely gradations of magnitude in
perennial plants; woods valuable for purposes of Art
and Manufacture are derived from all of them. But
as bulk and dimensions are necessary to make timber
available for extensive use, by far the greater part
of our ornamental woods are derived from trees.
There are, however, some remarkable exceptions.
The wood of roots is different in structure from the
wood of stems, and the same tree may furnish two
‘very difi'erent kinds of ornamental wood, according as
they are derived from-its ascending or its descending
axis. The wood of the inner portions of a stem may
be of very difi'erent colour'and quality from ‘that of
its outer parts. In the immediate neighbourhood of
the origin of branches, it may exhibit varieties of
pattern, such as to render it greatly more ornamental
than elsewhere, and in some cases, when under the
influence of morbid growth, reveals additional beau-
ties, so as to he prized for qualities which in nature
are defects. If we take a. number of transverse sec-
tions of wood, and compare them one with another,
it will soon become evident that there are two prin-
cipal types or modifications of structure. Compare
a cross cutting of oak or plane with a like portion of
“ Palmyra” wood, and you will see the differences
between them strongly contrasted. In the former, the
layers of wood are ranged in ‘concentric circles round
the central pith, and are encased externally in a bind-
1016
WOOD.
ing of bark, itself composed of distinct and‘difi'erently
organized portions. In’the latter, there is an “uniform
appearance throughout the section, the substance not
being disposed in concentric rings, ‘but appearing as
if a bed or ground of’ one kind was studded‘with
specks of another order of tissue.‘ These are not
slight dissimilarities: they indicate differences “of‘ the
greatest structural importance in‘ the economy of the
respective trees. Oorresponding with them are pe-
culiar modifications of every portion ofi‘the plant’s
organization. The external ‘aspect of "the? plants of
either type is altogether unlike that of the other.
The part played by the tree in‘ the landscape‘;~"the
share it has in determining the peculiarities of
scenery; the sentiment, so to speak, that it gives‘to
the living picture—are mainly" the results of the mo-
difications of external form, originating in minute
structure. Were it not that among woods used for
ornamental purposes, the first-‘named type has by far
the most numerous lrepresentatives, thesedifi'erences
would affect still more than theyinow do, the opera-
tions of the cabinet-maker. If we place a thin slice
of a young oak or plane under the microscope, we see
how complicated is its anatomical structure. In its
_central portion is the pith, composed of minute and
mostly hexagonal”calla—little’ membranous bladders,
that in the iearly stages ‘of the tree’s growtlr play
a more important part than they do\ during its ma-
turity. A great development of pith, as in the Elder,
renders the wood comparatively valueless. Around
this central tissue is a circle, chiefly composed of
very longspindle—shaped cells, each enclosing‘ a loose
spirally-coiled thread. ‘" This ‘is‘thermcdzlllary skieaflz
of botanists. ’ ‘It is interrupted‘ at‘ intervals >by\ radi—
ating extensions ‘of ‘the "piththat'proceed across the
next. element: of the ‘stem; the ‘true wood, towards
the circumference: ' " The 'wood *en'circles" in successive
layers the pith "and its“ sheath. It‘is composed of
tough fibres, mingled 'in more or less orderly arrange-
ment with vessels of various kinds, some of which
give it porosity. = In the first“ year of the ste’m’s
growth, there is "but' a single' layer\of the wood.
Year after year a 1fresh circle is’ superadded, and, in
temperate climates, at least, we can ‘pronounce with
certainty on the age of a tree by cdunting the number
of annual rings of growth displayed in itsrtransverse
section. In this manner, the age of certaiii trees has
been inquired into; and many, especially planes, cedars,
limes, and oaks,‘ have been shown. to have lived the
patriarchal existence of ‘nearly; or quite, a thousand
years; while yewdtrees grown in our "own country,
have exhibited unmistakeablesigns of thrice that vast
longevity. Around the wood are successive layers of
bark, the innermostfibrous, and investing the‘rnewest
layers of wood; the middle and outer ones cellular,
and often forming corky developments, Out of‘ the
inner layers of bark of ‘certain trees, cordage and.
matting are’ sometimes constructed; the ‘lime :espe-
cially furnishes such materials. The beautiful lace~
bark is this inner layer in the Lagetta lz'rztearz'a, one of
the spurge-laurel tribe. The surface of the bark is
itself invested with a thin pellicle of epidermis, con—

stituting the skin of the tree. This division into
pith, wood, and bark, is characteristic of the stems
of exogenous or dicotyledonous trees. In the stems
of endogenous or monocotyledonous trees—the Pal-
myra wood of commerce, or the section of a rattan
are examples—there {is no such distinction into these
three portions. The central mass is, it is true, more
or less cellular and pith-like in not a few of the Palm
tribe, butritris’so becauserfewer bundles: of vessels
and ‘fibres stud'it‘ than are 'toabe‘ifoundmeair the cir-
cumference. “it: is not‘ separated’ from» theneentral
portion by aasheath of> spiral vessels, IlOriYdOf medul-
lai~y rays proceed fromkiti fThewstemabesides, is not
invested by peculiar‘ and distinct bark; though the
densely-packed and tough .fibres ofritsi exterior ioften
form an. extremely tough cases i If. we cut (down the
stem of an teak or plane, ‘lengthways, and compare it
with a“ similar section of ‘ a palm, .we seeothat the “dif-
ferences so conspicuous in _the transverse, are" equally
manifestiim the longitudinal‘ section In the former,
the several parts are ranged inolines, th‘e sectionsrof
circles, “parallel to the central @pith; but-in the latter,
the lines of tissueidescribeimore ‘or less evident curves
manifested‘ by the directioiiuofvthe darker streaks,
indicating‘the presence of fibrous and {vascular bun-
dleszr“ Thesev curves, if traced‘ through? the "entire
length of ‘the stem, would "be found ‘to proceed\ from
the base“ of the leaves at its summit, to fun Zinwards
towards its centre,‘ and then outwards 'rtowards the
exterior, changing their minute structure “in the
several portions ‘of their course; and becoming at
last exceedingly tough and rfibrous, so asitorconstitute
the hard external investment. There’ are peculiari-
ties of anatomical structure distinctive of some exo-
genous trees, and which materially affect the quality
and properties of the wood. “If we‘compare the sec-
tion of a tree of the pine tribe with that of an oak
on elm, we shallfind in the former‘ an absence of the
conspicuous pores in the annuak belts of wood that
are so 'piainly seen in the latter ;' and with the aid of
the microscope, wershalhisee‘ that ‘this difi'erence is
due to minute peculiarities of organization. In the
pine, the peculiar_ vessels rcalled‘ dotteclvdacts; that
give porosityto‘wocd, are wanting‘; whilstithe woody
layers "are maderiup of diski-markedwqr ephnctated
fibres that are not!r t0~be Ysee‘n i’n'ither oak‘ioni elm, (or
invother trees‘ than those that havef‘cones’iforitheir
fruit, and'ltheir"immediatei'allies. 180 marked ‘and
constantris this *featureirof’ their str‘dctnregrthatr sec-
tions *takens from 'fossil coniferous ‘ itrieesi'exhibit <the
curious'disks that decorate their fibres; vthus, {by the
aid Of’tilfi‘ microsc‘cpepwie‘ aretenabled with certainty
to’ pronounce‘uponth‘e"'afiinities’ofi’plants that grew
countless zigesragogwhenfevery ‘living creature on the
earth’s surface was specifically ‘distinct from any one
now existing.“ * 1 ‘ ‘r M o " » a
a The appearance ‘styled 'salver-ymz'nein’woodois de-
pendent on the cellular tissue of the medullary
rays, and is, "therefore; exhibited by exogenous
woods‘ionly. It gives the ‘streaks of“ glancingssatiny
lustre,z that‘ are so ornamentah lin Jmany> 5 kinds of
woods. ‘In the oak. ‘and beech this appearance is
WOOD.
1017
conspicuous. The inner layers of wood, after the
tree has become aged, often become compact, and fre-
quently "different in colour from the new wood. They
are then styled the heart-wood. Botanists~term them
the clummen, and apply the name albm'mam to the
outer layers or sap-wood. In the former, the tissues
have become dry and dense, and charged with solidi-
fying deposits, so as to pretent them‘ aiding in the
ascent of the sap. Often, too, they become more or
less deeply colouredrso as conspicuously to contrast
with the pale sap-wood. This difference is especially
conspicuous in the ebony-tree, the black portion of
which is the ‘clummeiz, or heart~wood. In the oak,
the heart-wood is of a dark brown hue. In all trees
whose older woody layers undergo such changes, the
heart—wood is highly prized for purposes of furniture.
In willows, poplars, and chestnuts there is no dif-
ference of colour between the heart and'sap-woods.
Such are~styled white-woods. As a general rule, the
latter are not ”nearly so durable as the former. The
wood of coniferous trees appears to be least perish—
able; *a qualityiwhich is probably due to the pecu-
liarities above noticed, of their anatomical structure.
The forests of the “colder and temperate provinces
of the Old World, as well as those of corresponding
regions in America, are everywhere very similar in
physiognomy, being composed either of coniferous
trees, of which the pine,- the larch, and the fir are
characteristic examples; or ofrdicotyledonous trees,
among which the amentaceous, or catkin-bearing kinds,
are especially conspicuous. The ‘timber they furnish
is of great "value for useful purposes, and, among the
numerous varieties‘ in which they abound, are several
yielding highly ornamental woods. 'Theywant, how-
ever, the rich,’ brilliant, and intense colouring of
tropical woods, and are, for the most part, modest
in hue:
Among the foremost in the list of European
ornamental'woods stands the yew: This venerable
and picturesque tree is a native of most parts of
Elll'OPGH‘ThlS the Twas baccaz‘a of botanists, and is
represented in (North America by the very similar
Taxasrcmz‘adezzsz'sg bysome they have been regarded
as forms of the same species. The wood is close and
fine in the graina—hard' and compact ;* it is exceed-
ingly durable, indeed incorruptible, and capable of
taking a high polish. The colour of the heart-wood
is rich orange-red, deepening into dark brown, con-
trasting “with the rather’ scanty white sap-wood:
elegantly veined and marbled portions may be taken
from the: branching regions of the trunk and roots.
The sap-woodimay be stained so asto resemble ebony.
Furniture‘of exquisite“ beauty has been constructed
of yew-wood; indeed it iaadmirably adapted for
fancy cabinet-work, either’ in mass, or inlaid as veneers:
the supply is said, however, to be insufficient. The
wood of yew was once extensivelydused in the making
of bows. ~ *
The" cedar is a native of the warmer temperate
mountainous regions of Asia. The celebrity’ of the
cedar of Lebanon dates from a very high antiquity;
and the reputed value=of its-timber for ornamental

and cabinet purposes, has been placed on record from
very ancient times. Either, however, more coniferous
trees than one have been included under the popular
appellation—or the qualities of the wood have sadly
degenerated, for that of the existing cedar of Lebanon
is by no means remarkable for beauty, durability, or
sweetness of odour, all of which properties were pre-
eminently ascribed to it. The tree itself is as grand
as ever; one of the most majestic of arborescent
elements in the landscape. It was extensively used
among the ancients. Nevertheless, this wood, such
as we now know it, is not one to choose for carving
or house-construction. It is very light and spongy,
of a’reddish-white colour, scented like ordinary pine,
and not at ‘ all durable. It is possible that other
kinds of coniferous trees were confounded by the
ancients with the tree cedar. The Himalayan deodar,
a tree very closely related to the cedar of Lebanon,
really possesses all the good qualities for which the
latter has been so long celebrated. Travellers in the
East, in writing about cedars, often confound various
kinds of arborescent juniper under that name. The
cedar-wood, sometimes used for the making of drawers
in cabinets, and familiar in the shape of pencils, is
the product of an American species of juniper, the
best quality being that furnished by the Bermudan
juniper-tree ; a less valued sort is yielded by the
Jmzz'pems viryz'rzerma, a native of the Atlantic United
States, south of Lake Champlain. It is a ragged
tree, some thirty feet or so high, growing on dry
rocky hills. In both these pencil-cedars, it is the
heart-wood which possesses the desired colour and
qualities. Our native Juniper, though but a shrub,
produces a wood of worthy quality could it be obtained
of sufficient dimension and quantity. Its colour is
yellowish brown, often beautifully veined; it gives
out an aromatic odour. It is sometimes used for
turning; cups are occasionally made from it, and
walking-sticks. The wood of the Cypress was much
used by the ancients for ornamental furniture, espe-
cially in Greece, where that beautiful tree is indigen-
ous. It is among the most durable of all woods.
The numerous race of pines and firs for the most
part are more useful than ornamental, so far as their
timber is concerned. Some of them, however, afford
wood with many desirable qualities for furniture-
making. The stately spruce, that constitutes so fine an
element in the scenery of Northern Europe, and rears
its tapering trunk to the height of 150 feet and more,
supplies a light and fine-grained wood, easy to work
in every direction, and capable equally of taking a
high polish, or a black stain. It is a good wood to
bear gilding, and, from the facility with which it may
be glued, is much used for lining furniture, and in the
construction of musical instruments. Though pre-
senting no depth of colour, when polished and var-
nished it is highly ornamental, and in Norway and
Sweden pretty and effective household furniture of all
sorts is made of it. The wood of the larch, a native
of the mountain ranges of Central Europe, is simi-
larly used with like effect. It is of a yellowish. or
reddish hue, very strong, durable, and close-grained.
1018
WOOD.
It takes a high polish, and has the great advantage
over spruce wood in being free from knots. Ever
since the days of the ancient Itomans, it has been
used in the Arts, for the making of panels and
palettes. Another Alpine tree, the Plaas cemlra, a
native of the highest regions of pines, and among
the most soaring of its tribe, living at heights of 5
and 6,000 feet above the sea, furnishes avery durable,
fine~grained, and easily-worked wood, remarkable for
fragrance, which it retains for centuries, much to the
annoyance of bugs and moths, pestilent creatures
that have an unconquerable antipathy to its neigh—
bourhood. The colour of its heart-wood, which is
valuable for wainscoting, is a pleasant light brown.
The facility with which it can be carved has led to
its use among the shepherds of Switzerland and the
Tyrol, who cut it into ornaments; the little figures,
houses, &c., so often brought as curiosities from those
countries, are very frequently cut out of the wood of
.Pz'aas cembr'a. In the United States of America, the
wood of the Weymouth or white pine, Pleas stratus
of botanists, a tree of majestic dimensions, which
has been known to tower even to the height of 250
feet and more, is used for furniture—making. The
specific gravity of its wood is said to be less than that
of any other, except Lombardy poplar. In conse—
quence of its altitude, bulk, and straightness, it
yields timber of greater size than is furnished by any
other soft-wooded tree. When varnished, its wood
displays a pleasing yellowish or light red hue. It is
a beautiful material for wainscoting, and well adapted
for wood-carving. Hence it is used for the making
of picture frames, and is the favourite American
material for the figure-heads of ships. For the latter
purpose, the .Plaas Larz'cz'o, or Corsican larch, the
heart-wood of which is locally much used by cabinet-
makers and wood-carvers, is employed in the Medi-
terranean, as well as that of the silver fir, Plans picea,
one of the noblest trees of its family, a, native of
Central Europe and Western Asia. The larch of
America is a different tree from that of Europe;
it yields a close-grained and compact reddish or grey
wood, remarkable for strength and durability.
The wood of ancient coniferae, preserved in the
peat bogs of Ireland, the Isle of Man, and elsewhere,
and thus deeply stained with rich colouring matter,
has sometimes, though not so often as that of the bog
oak, been applied to ornamental purposes with con—
siderable effect. The bog yew of Ireland has espe-
cially been so employed, and some beautiful examples
of it were displayed at the Great Exhibition, where
were also specimens of veneers taken ‘from the roots
of the bog Scotch fir, well worthy of notice, and
suggestive of a more extensive use of this pre-
Adamite timber for, cabinet-making.
The oals, the c/zeslaul, the decals, the plane, and the
poplar, all represent genera belonging to the order
Amealaaea. The members of this group are all either
trees or shrubs, and not a few yield timber of value.
Preeminent stands the oak, a name applied to most
species of the genus Qua/"02.4.3. They furnish harder,
tougher, more compact, and more durable woods than

most trees. The oak of Britain is the Qaercas robar,
of which there are two very marked forms, that have
been regarded as distinct species and designated by
different names. It was at one time supposed that
the wood of one of these varieties was much superior
to that of the other, but we may regard this belief as
unfounded in fact, since each kind has advocates for
its superiority. The beauty of the wood of oak when
used for furniture and wainscoting depends partly
upon its pleasing, unassuming yellow—brown hue, so
inoffensive, and at the same time so attractive, to the
eye, and partly upon the variety and brilliancy of the
silvery streaks, lines, and curls that break what would
otherwise be the monotony of its colour. These are
caused by various arrangements and sections of the
rings of annual growth, and of the medullary rays or
wedges of cellular tissue. Of course the beauty and
variety of the surface will depend much upon the
mode of treatment of the plank by the cabinet-maker,
who has to take into account all the peculiarities of
the grain if he would develop the qualities of his
material. Mr. Holtzapffel remarks, that if we inspect
“the ends of the most showy pieces of Wainscot oak and
similar woods, it will be found that the surface of the
board is only at a small angle with the lines of the
medullary rays, so that many of the latter crop out
upon the surface of the work; the medullary plates
being seldom flat, their edges assume all kinds of
curvatures and, elongations from their oblique inter-
sections.” The value of timber, even of the same
species of oak, considered as ornamental woods, differs
according to the locality in which it has been grown,
and the best wood for ship-building and ordinary pur-
poses is not always that most suitable for furniture
work. Many of the finest examples of medieeval car-
ving were executed in the almost imperishable wood
of Qaercas rolar. The Turkey oak, Qaercas cerrz's,
furnishes a wood said by some to be highly orna-
mental; but this good character is somewhat doubtful.
The heart-wood of Qaercas z'lezv is also reputed to
have merit, nor should the cork-tree, another species
of oak, be passed without remark.
.The Beech furnishes a wood which varies in pro-
perties and value, according to the soil and locality
upon which it is grown. When grown in poor and
mountainous ground, the wood is white; but if the
produce of rich soils and plains, it is more or less red.
It is hard, unequally grained, yet close in texture,
and liable to the attacks of insects; nevertheless it is
much used for furniture—making, framework, joinery,
and turning. Though not capable of taking a very
high polish, it stains well, so as to simulate high~
coloured foreign woods, such as rose-wood and ebony.
It is well adapted for the purposes of the wood-cutter,
and for carving into ornaments of frames, and moulds
for culinary purposes. In the Northern United States,
the wood of the American beech is extensively used
for the making of chair-posts, and is turned into large
bowls, trenchers, and trays. ‘
A tree much used for the manufacture of furniture
in North America, is the c/zeslaat, apparently . a dif-
ferent species from that which is indigenous in the
WOOD.
~ 1019
Old World. It is said to be among the best of woods
for constituting the framework of articles to be cc-
vered with'veneers of more valuable materials, and to
be extensively used in the manufacture of bureaus and
sofas. The wood of the European chestnut (Spanish
chestnut), has at times been much used for carving
and cabinet-work, and resembles that of oak, but is
deficient in “flash,” and is not held in high esteem.
In the Levant, and eastwards, furniture is made from
the oriental plane, not deficient in beauty, especially
when constructed from the brown and very old wood,
and sometimes beautifully damasked. The tree itself
is one of the grandest features in the Turkish land-
scape, and attains gigantic dimensions. The occi-
dental plane is said to yield a close-grained, light-
coloured wood, capable of high polish, but liable to
warp. It is used in the making of musical instru-
ments. Birch-wood, from the Betula alba, is used in
Europe for the making of toys. The fine wood called
Russian maple appears to be a birch. The hlae/r hire/z
or mountain mahogany, Betula lenta of North America,
a tree which ranges from Nova Scotia southwards to
Georgia, yields a strong, firm, durable, easily-worked
wood, well adapted for panelling and furniture; its
colour is a delicate rose, deepening, but not becoming
sombre, with age. The paper hire/i, Betula pappraeea,
whose bark is so useful to the Canadians, who make
of it their simple, but effective and elegant canoes,
also baskets, boxes, and folios of singular lightness
and beauty, many of which were conspicuous in the
Canadian department at the Great Exhibition, is
valuable for its timber also. The heart-wood is red;
the sap-wood is white, with a pearly lustre, and
capable of taking a high polish. Furniture is made
from it in Canada and the States, and elegant cabinet-
wood from the feathered and variegated portions
taken from the regions of the trunk whence the
branches spring. The orange and deep reddish wood
of the alder, when knotted and curled, is used occa—
sionally for ornamental work, and frequently for toy
making, as are also the poplars, yielding white and
clean-cutting wood, ‘easily worked and carved, and
capable of being ‘used asv a substitute for lime-tree.
Nor must we omit all mention of the willow and the
osier, the softest and lightest of our European woods,
valuable for bonnet—making, baskets, &c., when planed
into chips. -
Among the natural orders that have affinities with
the catkin-bearing trees, are the Walnut and the
Nettle tribes. In the former, we find the valuable
tree which gives the group its name. The repute of
wahiut timber for beauty and capability is of ancient
date, since we find it praised by Greek authors for
furniture; and though for a time exotic woods sup-
planted it, there is as much preference shown for it
now as ever. In value it will probably increase, since
fine trees are not over-common; and the application‘,
of the wood to the making of gun-stocks during the
war, led to a prodigious destruction of European
walnut-trees. The combined qualities of lightness,
rich—colouring, solidity, compactness, durability, faci-
lity of working, and freedom from warping, place the

heart-wood of the walnut high in the scale of furni-
ture timber. Many very beautiful efforts of the artist-
carver have been executed in this material. The
veined and cambleted roots yield beautiful veneers,
highly esteemed for ornamental work. The yellowish
sap—wood can also be used for permanent purposes,
when rendered preservable and defended against the
attacks of insects, by the simple process of boiling in
walnut oil. The true walnut, or Juylans regia, is
believed to be a native of Persia. The black walnut,
Jar/[ans nigra, is a North American tree, of consi-
derable dimensions, growing to a height of 60 or 70
feet, and attaining a diameter of 3 or 4: feet. Its
wood is much used for furniture in America, and
numerous fine examples of it were displayed in the
Crystal Palace. It is imported into England for
cabinet-making. Its colour is dark violet or purplish
grey, or purple deepening with age. The grain is
fine; tenacity, hardness, strength, durability, and
capacity for polish are among its good qualities. The
butternut, Juglans oinerea, is another American species
of this genus, a low tree, yielding a pale red, durable,
light wood, with considerable capabilities for orna—
mental uses. The hiehorg/ also belongs to this tribe,
though to a different genus, Cam/a. Its timber is
more useful than ornamental. The elm is a member
of the Nettle tribe. The excrescences of its trunk
are employed for ‘decorative purposes. The mulberry
is occasionally used for fancy purposes, and the lila-
clsra aurantiaea, an allied tree from Arkansas, is said
to yield a close-grained, durable, hard, and polishable
wood, remarkable for its rich saffron-yellow colour,
well worthy of the attention of cabinet-makers.
Among the Mediterranean trees, not natives of
middle Europe, is the C'eZtis australis, or Nettle tree.
It furnishes thehois ale Perpignan, an extremely com-
pact wood, hard and dense, and capable of taking a
high polish. Cut across the grain and polished, it
resembles satin-wood. In the south of Europe, it is
used for furniture, flute-making, and carving into
figures of saints, and circulates extensively over many
countries in the shape of handles for whips. The
American nettle-tree, called also beaver-wood and hoop-
ash, is a different species, and rare, but has probably
similar qualities. The hack-hemp, another American
kind of Celtis, is one of the finest of the forest trees
on the banks of the Ohio; and yields, according to
Michaux, a fine-grained and compact wood, perfectly
white when first cut,‘ and apparently possessed of
valuable ornamental qualities. The Zel/roua, a North
Persian species of ,Planera, a genus of the Nettle
family, yields a fine furniture wood, not much known.
The hon: belongs to the spurge tribe. It produces a
warm yellow wood, much used by the turner, and
well adapted for the construction of flutes and similar
musical instruments. It is the yellow wood which
we often use in the shape of rules and scales, and it
.is also the chief wood employed in wood-engraving.
It is sometimes beautifully mottled. In Britain we
have the box growing wild and luxuriant in Surrey,
as at Box-hill; but the chief supply of this wood is
derived from the southern parts of Europe, and from
1020
WOOD.
Asia Minor. A distinction is drawn between “Turkey”
and “ European” boxwood. The latter is more curly,
softer, and paler than the former. Dr. Hoyle has
called attention to a different species of Bums, a
native of the Himalayas, yielding a wood possessing
similar qualities with that in common use, and having
the advantage of being found of considerable size and
thickness. The ask and the olive are members of the
olive family. The former familiar tree yields a timber
remarkable for toughness and elasticity, and excellent
for machine and agricultural purposes, but not much
used for finer applications. When, however, the grain
is zigzag, it is adapted to the making of furniture of
considerable beauty. Olive-wood is imported from
the Mediterranean countries. It is veined with dark
grey, and resembles boxwood in texture, but is softer.
The knotted and curled roots are made into embossed
boxes. This is done by means of pressure in engraved
moulds of metal. The Izollg/ type of the family Ili-
ciazew, whilst among the most ornamental of our
smaller native trees, is at the same time much valued
for its wood, which is very fine grained, and, when
properly prepared, being satiny, close in texture, and
not liable to stain superficially, though capable of
taking an intense dye. It is highly prized by the
manufacturer of Tunbridge—ware, and much used in
the making of screens, squares of draft boards, and
lines of cabinet—work. The holly of North America
has similar qualities, and is applied to like uses.
In the family of heat/28, there is one European
genus, whose members furnish a wood adapted for the
cabinet-maker, although not much used. This is the
Arbutus or strazooewf/Jree, of which there is more
than one species indigenous and abundant in the
countries bordering upon the Mediterranean. A
colony ‘of the Aromas zmeo'o flourishes upon the
islands and shores'of the Lakes of Killarney. The
hard and close-grained, warm-tinted wood of this
tree is occasionally used by turners, and converted
into ornamental articles, such as inkstands and book-
cases. Among the many‘petalled flowered exogens
are not a few tribes that include trees of value for
their timber as well as for the excellence of their fruit
or the elegance of their flowers. The first we have
to mention, however, is not very remarkable in any of
these respects; it is the camel or dogwood, Camus
sanguinea, a shrub abundant in our English thickets. 1
Its wood is used for skewers and such ignoble instru-
ments ; its higher use is that to which it is applied
by the watchmaker and Optician, who avail themselves
of its freedom from grit, to make instruments of its
splinters for cleaning fine machinery or lenses. An
American species, the Comasflorz'da, produces a hard,
heavy wood, capable of taking a good polish, and
used on the other side of the Atlantic as a substitute
for box-wood. The Aralz'acew, a natural order to
which the ivy belongs, may be mentioned here inci-
dentally on account of the substance so well known
as rice—paper. This was long supposed to be the pith
of a leguminous plant; its~true nature was not made
known until lately, when Sir William Hooker demon~
strated that it was the pith of an araliaceous tree:

A living plant had been procured with great difficulty
from the Chinese, and was sent to England, but died
on the passage. It is said to be exclusively a native
of the island of Formosa.
In the family of Rosacm we find the greater num-
ber of our useful woods derived from trees with con-
spicuous flowers—not from roses and brambles, but
from the members of the apple and plum tribes, which
are sections of this beautiful group. The wood of
the apple itself is one of the most used. It is mode-
rately hard, often rich in hue and close—grained. It
works well and clean, and is adapted for turning.
Like the other woods of the tribe, it is employed for
chair-making. The hole of the tree only is used, and
the wild apple or crab is often preferable to the cul-
tivated ; as also with the pear, the light brown wood
of which is valued by the maker of Tunbridge-ware.
It carves well, cutting cleanly in all directions of
grain. It requires to be well seasoned, however. I t
takes a black dye with facility. Blocks for calico—
printing and paper-staining are often cut out of it.
The service-tree is said to yield a useful dark red wood,
tough and lasting. The medlm' is seldom used, its
wood is pale and rather soft. The mountain ask pro-
duces a hard and fine-grained, light-coloured wood,
capable of taking a good polish: a character applicable
also to that of the common hawthorn. Among the
best rosaceous furniture woods is the Cherry. It is
of a pale reddish hue darkening to brown: its grain
is hard and close. It works easily and takes a fine
polish, becoming of a ruby tint when oiled or vrrxnished,
and takes a good stain. It is extensively used by
cabinet-makers. Nor should cherry pipe-sticks be
forgotten. The Mao/o okerry of the United States,
(Cemsus serot‘z'azra) a tree that grows even to 100 feet
in height, yields a fine, close-grained, light red wood,
darkening with age, and beautifully glanced, with
abundant silver-grain. The attention to our cabinet-
makers might be directed with advantage to this tree.
The wood of the Plum is richer in hue than that of
the cherry, but is not so serviceable. It, as well as
that of the BZacM/tom, is used in the making of
Tunbridge—ware and other fancy cabinet-work. That
of the Apricot has a fine and hard grain. The almond-
troe, especially when wild, is said to furnish a valuable
wood, but which is little known or used. The great
order of leguminous plants, the Pulse tribe, is rich
‘11. trees, but not much so in temperate climates, nor
is there any ordinary tree of the group upon which
stress can be laid. That best known is the locust-tree,
or what is commonly, though incorrectly, called by the
name of Acacia. It is the Robz'm'a pseuclacacz'a of
botanists. It produces a yellowish or reddish wood,
compact and lasting, with a fine texture and abundant
silver-grain. It is used for turners’ work, for furniture
and for cricket-stumps. The dark brown or greenish
wood of the Labzmzm/z, streaked with white silver-
grain, is well adapted to ornamental purposes. Some
other arborescent species of Qytz'sus differ from it in
tint and quality. The fustic of the Levant, a yellow
dyewood, belongs to the order Amcarclz'aceae, so named
after the “tallow-mu.‘ genus. In that of Celas‘zfracece is
WOOD.
- 1021
included the well-known Spindle—tree, furnishing a
yellow wood fit for such articles as thread-reels and
bobbins. Its charcoal has peculiar merits for the
purposes of the artist. ~
The wood of the European lime-tree has qualities
which render it highly valuable for ornamental carving,
although it "is of little use as building timber. The
beauty of its creamy white colour, the closeness and
firmness of its grain, its softness and lightness, render
it admirably adapted for the purposes to which it is
chiefly applied.‘ Carriage-panels, sounding-boards for
pianos, toys, and boxes are made of it, as well as
furniture intended to be inlaid. It is one of the
materials used in wood-mosaic; and the white por-
tions of the patterns executed in Tunbridge-ware are
mostly constructed of lime—tree. Its ‘fame for pur-
poses of sculpture in wood dates from very ancient
times, and it is therefore mentioned with praise by
more than one classic poet. Some of the finest of
the carvings of Grinling Gibbons were executed in
lime. Although this tree is extensively grown in
Britain, it is not planted now so frequently as for-
merly, and although believed by many botanists to be
a native of our country, it must practically be re-
garded as a foreign wood. The north and east of
Europe are its chief indigenous haunts, and in Lithu-
ania there are extensive forests of it; the chosen
places for rearing of bees, whose honey, if they be
fed upon the flowers of the lime-tree, becomes pecu-
liarly delicious in flavour. -' In North America its
place is taken by a representative species, ‘growing
under similar'conditions,‘ and furnishing a wood pos—
sessing similar qualities, soft, white and close-grained;
it is much used by the cabinet-makers of the States,
and by the sculptors of figure-heads for vessels on
the Transatlantic rivers.
In the maple lrz'le are several valuable trees for
ornamental purposes. The sycamore is one of the
most familiar. It is compact and fine-grained, rather
soft, easy to work, susceptible of polish, and not liable
to warp. When young, it is white and silky; when
old, yellowish or brown. It is sometimes variegated,
and is then most’ sought after. In days of yore it
furnished the wooden platters and other household
instruments that reposed upon the old English dresser.
Now it is extensively employed in the manufac-
ture of musical instruments and purposes of turnery.
The common maple was more honoured anciently
than now, and by the Romans was chosen for the
making of ornamental tables. It is fine-grained, and
capable of taking a high polish. Butter~prints and
such like articles are carved out of it. It is well
adapted for turnery. Its knotted root-wood is highly
ornamental, and applied to the manufacture of fancy
snuff-boxes, &c. More valuable are some of the
maples indigenous to North America. What is called
the bz'rcl’s-epe maple, remarkable for the beauty of the
figures described in the section of it, is not a peculiar
kind, but particular portions of the tree, full of small
knots or embryo-buds ; these, according to the direc-
tion in which they are cut, describe various patterns.
What is called earlerl maple is dependent for its pecu-

liarities on the direction of the woody fibres, and is also
no special sort. Both curled and bird’s-eye varieties
are usually procured from the Acer saee/zarz'azam or
sugar-maple. It is a tree that in the forest grows to
60 or '70 feet high before branching, indigenous to
Canada and the Northern States. :Its wood is compact,
hard, and capable of taking a fine polish. It is much
valued by cabinet-makers. The real maple of North
America is another tree esteemed for purposes of
furniture. Its wood is reddish-white, fine-grained,
and close, with narrow strips of silver-grain. It
polishes well, and is sometimes curled and blistered;
the former qualities, as in the sugar—maple, depending
on an undulation of the grain; the latter, upon the same
cause that produces the bird’s-eye appearance. It is
extensively used for the making of common furniture
in the States, but is deficient in strength and not very
durable. The white maple, (Aeer erz'ocarpam,) another
American species, is used for the making of tools.
The Aeer plalanoz'cles of the mountainous regions of
Europe is applied to similar purposes with the syca-
more. The beautiful wood known as Russian maple
is said to be really the product of a species of birch.
The dlae/c as/z. of North America, (Negamlo fi‘aairzi-
f0lz'am,) yields a yellow wood adapted for inlaying.
In the order Sapz'rzclaeeee, we find one tree of tem-
perate climates furnishing an ornamental wood. It is
the lzorse-elieslrzul (_Eeealas fiz'ppoeasz‘aaam), no relation,
however, to the true chestnut. It yields a soft, 'close-
grained, white wood, turning well, and much used in
’l‘unbridge-worl<:. The white backs of brushes ‘ are
often made of it. It is employed in inlaying. The
yellow wood of orange-trees is occasionally employed
for ornamental purposes, but is of little value. The
tulip-tree (Lirz'oclemlrorz lalz'pzj'era), Well known now in
our gardens, is anative of the Western United States,
where it grows to a height of 140 feet. It is one of
the Magnolia tribe, and is often set down as ‘producing
the well-known and beautiful tulip-wood. This is a
mistake; its wood is white, soft, andfine-grained. It
is not much valued.1 ~ ~ - -
The above notice includes some of themost import-
ant woods employed in the useful and ornamental
arts. A few'woods of especial interest ‘have been
noticed under separate heads. [See MAHOGANR]
The‘ table on page 1022, compiled by the late
Mr. Holtzapfi'el, gives the names of most of the woods
employed in Great Britain, together with the uses to
which they are applied. a
The quantity of wood annually imported into Great
Britain is about 2,000,000 loads, or 100,000,000 cubic
feet ; hence it is of great importance to ascertain from
what quarters this immense amount can be Obtained
with .the least risk of failure in the supply. The col-
lections of woods brought together at the Great Ex-
hibition, amounting to several thousand specimens,
were in this respect most valuable, and revealed a
large number of woods which had been previously
wholly unknown to commerce, and some of which
were even unknown to the botanist. There are now

(1) The “ Art Journal,” 1853.
WOOD.
TABULAR STATEMENT OF THE WOODS COMMONLY USED IN GREAT BRITAIN.


FOR BUILDING. FOR TURNERY. FOR FURNITURE. MISCELLANEOUS PRO-
Skip-building. Common woods for toys.- sqftest. Common furniture, and inside PERTIES'
Cedars. Alden war/‘8' Elasticity.
Deals. Aps_ Beech. Ash
Elms. Beech Birch. Haiel
Firs. Birch } smau- Cedars. Hick '
Larches. $2,110,“ Cherry-tree. Lancgry' d
Locust. Willow, Deal. S ‘W00 '
. weet chestnut, small.
Oaks. Pines. S ak a
Teak, &c. &c. YEW e‘woo '
Best woods for Tnnbrz'olge-ware. Best furniture. '
~Wet worlrs, as piles, founda- Ambo na
tions, &c. HOHY- . B1 ky b ' Inelastic-fly and toughness.
Horse-chestnut white ac e Ony-
Alder. Sycamore woods Cherry-tree. Beech.
Beech. Apple_tree ' Coromandel. Elm- .
Elm. pear_tree brown woods. Mahogany. Llgnum vitae.
Oak. plum_tl.ee Maple. Oak.
Plane-tree. Oak, various kinds. Walnut.
White cedar. Rose-wood.
, - Satin-wood. . .
House-carpentry. Hardest Dz‘ghsk woods. Sandal-wood. Even gram’properfor Galvin-9'
D a1 Beech, large. Sweet chestnut. Lime-tree_
02k 5' Box. Sweet cedar. Pear-t1-ee_
Pi‘nés Evulip'lzooi Pine.
' a . a nu .
Sweet chestnut‘ Walnut. Zebra-wood. _
Durability m dry worlrs.
m Cedar.
Oak.
ron MACHINERY AND gong-1 t t
MILL-WORK. Ywfie flies,“-
FOREIGN HARD WOODS, SEVERAL OF WHICH ARE 8 OW ea '
Frames’ &0' ONLY USED FOR ORNAMENTAL TURNERY.
Ash. Colouring matter.
Beech. 1. Amboyna. 19. Mahogany.
Birch. 2. Beefwood. 20. Maple. RED DYES~
Deals. 3. Black Bot. B. wood. 21. Mustaiba. Brazil.
Elm 4., Black ebony, 22. Olive-tree and root. Brazilletto.
Mahogany. 5. Box-wood. 23. Palmyra. Cam-wood,
Oak. 6. Brazil-wood. 24‘. Partridge-wood. Log-wood.
Pines. 7. Brazilletto. 25. Peruvian. Nicaragua.
8. Bullet-wood. 26. Princes-wood. Red sanders.
Rollers, &c. 9. Cam-wood. 27. Purple-wood. Sapan-wood_
B 10. Cocoa-wood. 28. Red sanders.
Lgflhm vitae 11. Coromandel. 29. gosetta. d GREEN DYE.
_° ' 12. Green ebony. 30. ose~woo . .
Mahogany’ 13. Green heart. 31. Sandal-wood. Gwen ebouy'
14.‘. Grenadillo. 32. Satin-wood. . w S_
Teet/z of wheels, &c. 15. Iron_wood_ 33. Snake_wood_ Fulliljm DYE
0 1,3,. . 16. King-wood. 34. Tulip-wood. * '
1,21,15,32, 1'7. Lignum vitae. 35. Yacca-wood. Zimle'
Locust. 18. Locust. 36. Zebra-wood. SCENT.
F d Nos. 3, 8, 16, 33, and 34, are frequently scarce. Camphor-Wocd.
0”” 717/ Paflems- Nos. 3, 5, 8, 9, 10, are generally close, hard, even-tinted, and Cedar,
Alden the {D013 proper for eccentric turning, but others may also be Bose_woodo
e .
Peal‘ mhlfoglli, 5, 10, 12,14, 17, 18, 19, 30, 32, are generally abundant gmtdal'wogd"
Mahogany‘ and extensively used. All the woods may be used for plain atm'woo '
Pine. turning, Sassafras. s-


The woods used in our Government yards for ship-building are as follows :--
OAKS.—English. Adriatic. Italian. New Forest. Canada, white and red. Pollard. Istrian.
African, and also Teak.
Pines—Yellow. Red. Virginian. Nil red. Pitch pine. Riga.
Ems—Norway and American spruce fir. Dantzic and Adriatic fir.
Lancmts—Hackmetack. Polish. Scotch. Italian, 1, 2, 3. Athol. Cowdie, or New Zealand larch.
Cannes—Cuba. Lehanus. New South Wales, and Pencil cedar.
ELMs.-_English and Wych elm.
MISCELLANEOUS Woons used in small quantities.,—Rock elm. English and American ash. Birch, black and white. Beech.
Hornheam. Hickory. Mahogany. Lime-tree. Peon-wood. Lignum Vitae, &c.
Live-oak.
Sussex.
WOOD‘.
1023
eight descriptions of timber admitted as first-rate for
ship-building purposes, and one of these has only been
_ so ranked since the opening of the Great Exhibition.
They are :—1, English oah ; 2, American lioe-oah ;
3,11friean oale; 4.4, illorunp saul ; 5, East Indian tea/e,-
6, Green-heart; 7, Morra ,- 8, Eon-heart: (the newly
admitted wood). Of the above, the Morra, and the
Green-heart, are trees of British Guiana. The timber
called African oak is the produce of an unknown tree,
certainly not an oak.
with in the southern states of North America, but
never in inland forests or at a distance of more than
15 or 20 miles from the sea, the air of which seems
necessary to its existence. It is A0 or 50 feet high,
and a close—veined, even wood. The Mor-ung saul is
an Indian tree, as well as the better known and valu-
able Teak. The Iron-bark is from New South Wales,
and has a density of 14:26, and a strength of 1557, '
(English oak being called 1000.) It resembles plain
brown Spanish mahogany, but it seems to be the
heaviest and most solid of all woods. From the same
quarter of the world were derived some specimens
of a gigantic species of Eucalyptus. One of these
trees, It feet in diameter, was cut down for the pur-
pose of our Exhibition, and a plank of that width
would have been sent over, if saws of the requisite
length could have been procured. Two slices or sec-
tions, however, were cut from the stem of one of these
magnificent trees: the larger section, taken at the
height of £1 feet from the ground; was 6 feet in dia-
meter, and the smaller section, at a height of 134. feet,
just below the first branch, was nearly 3 feet in dia—
meter. Several beautiful ornamental woods also came
prominently into notice at the Great Exhibition, such
as the mush-mood, hlaeh-woorl, and Huon pine, of Van
Diemen’s land, and the reel ebony of South Africa.
The collection of East Indian woods by Dr. Wallich
contained about 4.150 specimens, and consisted of the
woods of Nepal, those of Tavoy, those of Gualpara,
and those grown near Calcutta. Other collections by
Dr. Boyle, Colonel Frith, and other gentlemen from
various parts of India, including woods of the Indian
Archipelago and Ceylon, formed upwards of 30 distinct
collections, the particulars of which are given in the
Jury Report, Class IV. ; where it is remarked, that
“ the nature and properties of many of these Indian
woods is very little known, and though, for the most
part, it is not probable that it would be found worth
while to import them into Europe, yet their import~
ance to India is every year increasing, and must
necessarily continue to do so, as the demand for tim-
ber in India for railways and other engineering pur-
poses increases. For such uses it is desirable, not
only that the wood should be strong and not liable to
decay from mere exposure to the weather, but also,
that it should work freely, and be able to withstand.
the ravages of the various insects to which wood of
all kinds is more or less exposed in tropical countries.
It is true, that even the most porous and spongy
woods may be rendered capable to some extent of re-
sisting all such influences, by being impregnated with
various solutions, as in the processes of-,Kyanizing,
The American live-oak is met.

-&c., but it is obviously far better, when possible, to
select such woods as are naturally saturated with
resinous‘ and aromatic substances, as in this latter
case all cost of preparation is saved, besides that the
preserving matter is far more perfectly disseminated
throughout the whole of the wood than can possibly
be effected by any artificial process after thetreeis
felled. ‘In examining the comparative value of differ-
ent sorts of wood, it is of the first importance to ascer—
tain the nature of the encrusting matter deposited
throughout the cells and tubes of the wood. For all
practical purposes those woods appear to be best in
which the cells are lined with resinous matter, those
filled with hygroscopic gummy matter are, for the
most part, of less value; they» are seasoned with diffi-
culty, and are. always more liable to decay. The best
woods are those having a strong fibre, protected'from
all external influences by a coat of resinous matter, or
at least of a matter insolublein water, and one which
does not attract atmospheric moisture.”
The table on page 1024 (abridged from the Jury
Report) contains a list of the woods grown in Great
Britain, specimens of which were exhibited, with cer-
tain interesting particulars attached.
The total annual importation of timber into Great
Britain (the average quantity of which is stated,
p. 1021) is entered under the several designations of
timber, or 'unsawn wood, deals and planks, or sawn
wood, teak-staves, and lath-wood.
The following table shows the countries from which
wood was'chiefly imported in the year 1849 :-- '



Timber. Deals. Teak. Staves. Lam‘
wood.
41,419 173,586 - 325 15,539
Sweden 28,079 79,843 —-- 150 1,119
Norway 28,930 50,805 -— 95 103
Prussia....................... 117,470 35,006 —- 19,213 6,169
Hanse Towns 2,441 68 -- 1,012 --
Tuscany 2,299 9 -- --- ——
Papal Territories . ...... .. 2,106 3 —- -- ~—
Western Africa..."......... 1 -- 9,596 —- r -—
British India............... 1 2 17,459 5G --
aliiOGII-ocl'lluncn. 1 4' —~
British North America.. 578,748 468,572 9 45,614 14,813
British Guiana............. 4 19 4 103 --
United States 13,832 839 -- 13,309 --
Miscellaneous 1,002 491 633 36 57
Tornr. Loans .... .. 817,909 809,783 27,702 79,917 37,800

In the year ending 5th January, ‘1853, the quantity
of timber imported and entered for home consump-
tion was as follows :—


i Enteredfor
Imported. Home
L Consumption.
Timber and wood: battens, batten-
ends, boards, deals, deal-ends, and
plank, foreign ........great hundred 12 --
Deals, battens, boards, or other
timber or wood, sawn or split :—
Of British Possessions.....loads 572,401 571,281
Foreign ...loads 550,324 551,608
Staves ...............loads 86,799 free.
Timber ‘or wood, not being articles
sawn,or split, or otherwise dressed,
, except hewn, and not otherwise
‘ charged with duty :—
Of British Possessions ...Zoads 584,250 582,975
Foreign ...loads 341,319 391,512

102 t WOOD.



33g 0 _
Name. gggsvetgf Remarks.
0 (G
E 3 :33.
1b. oz
Abz'cs excclsa (spruce fir) . . . . . . . . Oxfordshire . 27 2 434: Used for scaffold-poles, ladders, common car-
entry, 8w.
Ace?‘ campeslre (maple) . . . . . . . . . Oxfordshire . 37 l 593 Usléd for ornamental work when knotted; it makes
the best charcoal, and turns well.
Accrjosczldo-platamls (sycamore) . . . . Wandsworth. 341 11 555 Us'ed1 hi1 dry carpentry, turns well, and takes a fine
0 18 .
Esculus lzz'pjoocaszfavwm (horse-chestnut) Wandsworth. 24 2 ‘386 Uslfad for inlaying toys, turnery, and dry carpentry.
Alzzus glulz'nosa (alder) . . . . . . . . . Osfol'dshlre - 23 8 ‘376 Used for common turnery-work, &c. ; and lasts long
under water, or buried in the ground.
Arbutus zmcdo (Arbutus) . . . . . . . . Killarney . . 45 6 ‘726 Hard, close grained, and occasionally used by turners.
Berber-2's oulgarz's (barberry) . . . . . . . . ._ . - - - - 37 11 ‘603 Used chiefly for dyeing.
Bcz‘ula alba (common birch) . . . . . . Eppmg . . . 34' M ‘558 Interior in quality, but much used in the north of
_ England and Scotland for staves for herringbarrels.
C'aayaimls .Bclulus (hornbeam) . . . . . Eppmg . . . 40 5 ‘64:55 Very tough, and makes excellent cogs for wheels;
forms a good charcoa-, and is much valued for fuel.
C'asz‘anea ocsca (chestnut) . . . . . . . . Cornwall . 36 7 583 Used in ship-building, and is much in repute for
posts and rails, hop-poles, 8m.
Ccrlrus Libam' (cedar of Lebanon) . . . . . . 38 13 621 Used for furniture, and sometimes for ornamental
joinery work.
Cemsus vulgezris (common cherry) . . . . . . . . . . 33 3 531 Excellent for common furniture, and much in re-
puts; works easily, and takes a fine polish.
Oorylus Avellana (common nut) . . . . . . . . . . . . 36 0 '57 6 The young wood is used for fishing-rods, walking-
sticks, 8:0.
Cratlcgus oxyacamfka (white-thorn) . . . Epping . . . 45 1a ‘734.. Hard, firm, and susceptible of a fine polish.
Capressus scmjocroz'rens . . . . . . . . . Mortlake . . 34 10 ‘554: Fine grained, and fragrant; very durable.
C'g/lz'sus laburnum (common laburnum) . Oxfordshire . 415 9 ‘729 Hard and durable, and much used by turners and
omers.
Euonymus Europczus (lance-wood) . . . . . . . . . . . 34: 0 ‘5% WJood used for skewers, and is hard and fine grained.
Fagus syloatz'ca (common beech) . . . . Oxfordshire . Al 2 ‘658 Much used for common furniture, for handles of
tools, wooden vessels, 8:0. &e., and when kept dry
is durable.
Fraxz'nus excclsz'or (common ash) . . . . Oxfordshire . 36 11 '587 Very tough and elastic; is much used by the coach-
maker and wheelwright,and for the making of cars.
Ilcx aqug'folz'um (holly) . . . . . . . . . . . . . . . . . 4d 9 ‘665 The best white wood for Tunbridge—ware; turns
well, and takes a very fine polish.
Juglans regz'a (common walnut) . . . . . Sussex 36 1 ‘577 Used for ornamental furniture, much in repute for
gunstocks; works easily.
Laria- Europrca (larch) . . . . . . . . . Oxfordshire . 35 0 ‘560 Used in house-carpentry, and for ship-building; is
durable, strong, and tough.
M07156‘ m'gm (common mulberry) . . . . Mortlake . . 4:1 5 ‘661 Sometimes used for furniture, and by turners, but is
of little durability.
Pz'nuspz'cea (silver fir). . . . . . . . . . . . . . . . . . 23 2 ‘370 Used for house-carpentry, masts of small vessels, &c.
.Pc'nus sylocsz‘o'z's (pine) . . . . . . . . . . Oxfordshire . 24: 5 '389 Much used for rafters, girders, and house-carpentry.
Plalanus oriemfalz's (plane) . . . . . . Wandsworth. 39 12 ‘636 An inferior wood, but much used in the Levant, for
furniture.
Populate alba (Abele) . . . . . . . . . . . . . . 27 11 ‘44-3 A light soft wood, of little value.
Popular diliz‘afa (Lombardy poplar) . . . . . . . . . 21 13 3A9 Soft and spongy, rapidly decaying, unless kept dry.
.Przmus domesz’z'ca (damson) . . . . . . . Wandsworth. 4:5 8 '728 Hard and fine grained, but not very durable; used
for turning, &c.
Pmmzcs laurocemsus (laurel) . . . . . . . . . . . . . . 46 144 ‘750 Hard and eolinpaet, taking a good polish.
Prmms spinosa (blackthorn) . . . . . . Oxfordshire . $3 11 ‘699 Hard, capable of a fine polish, but apt to split.
Pym: aucuparz'a (mountain ash) . . . . Yorkshire . . 38 6 ‘61% Fine grained, hard, and takes a good polish; used
in turnery, and for musical instruments.
Pyrus commum's (Burgamot pear) . . . Bermondsey . 38 9 ‘617 Strong, compact, and close grained; used for turning
handles to tools, &c., and takes a good black dye.
Pyms mains (crab) . . . . . . . . . . . . Yorkshire . . d5 6 ‘726 Hard, close grained, and strong.
Pyrus sorbus (service tree) . . . . . . . Epping . . . ‘L6 11 ‘7417 Hard, fine grained, and compact; much in repute by
_ millwrights for cogs, friction rollers, 8ze.
Qncrcus elcz' (evergreen oak) . . . . . . Wandsworth. 4:7 5 '7 57 Wood very shaky when aged; is durable and strong,
, and makes an excellent charcoal.
Qucrcuspcdzmculala (Engllsh oak). . . Sussex . . . . 39 0 ‘6244 This oak is much esteemed for ship-building; the
_ _ strongest and most durable of British woods.
Qflercus scsszlg/lora (Welsh oak) . . . . . . . . 37 11 ‘603 A good wood for ship-building, said to be inferior
- - - - to the common oak.
liqizgigtcfef‘fam (c‘m‘mn acacla’} Epping . . . is r -705 Much used for treenails in ship-building, and in the
_ ' _ ' ' ' ° ' ' ' ' ' ' ' ' ' United States is much in repute for posts and rails.
Salsa: alba(wh1te willow) . . . . . . . . Surrey. . . . 24.. 14.1 '398 Used for toys, and by the millwright; is tough,
I . elastic and durable.
Salas: caprea (palm sallow) . . . . . . . Oxfordshire . 24. 8 ‘332 Tough and elastic; is much used for handles to
_ . _ _ tools, and makes good hurdles.
Salzxfragzlzs (crack willow) . . . . . . . Oxfordshire . d2 0 ‘392 Light, pliant, and tough; is said to be very durable.
Taxus baccala (yew). . . . . . . . . . . . . . . . . $1 9 ‘665 Used for making bows, chairs, handles. 820.; the
wood is exceedingly durable, very tough, elastic
_ _ _ and fine grained.
Tzlza Europrca (common hme) . . . . . Wandsworth. 27 3 ‘435 Useddfor cutting blocks, carving, sounding-boards
an to s.
Ulmus campestris (English elm). . . . . . . . 3O 9 — Used inyship-building‘, for under-water planking,
and a variety of other purposes, being very
durable when kept wet or buried in the earth.
Ulmus mmzlarza (wych elm) . . . . . . . Oxfordshire . 35 14: '5741 Consideredlbetter than common elm, and is usedin





carpentry, ship-building, &c.


WOOD.
i025
The various methods of jointing timbers are de—
scribed under GARPENTRY—BRIDGE, Sec. iv.-Sn1r,
&c. MARINE Gnun'patented by Mr. Jeffery in 18412,
possesses very powerful cementing properties. _ It is
formed by dissolving llb. of caoutchouc in small
pieces in 4'! gallons of coal naptha with frequent
stirring, the solution occupying 10 or. 12 days.
2 parts shell—lac are then fused in an iron vessel, and
1 part of the solution being stirred well in, the glue
is poured out on slabs to cool. - When two pieces of
wood are glued or cemented by its means, the joint
becomes stronger than the fibres of .the wood itself.
Large masts being formed of pieces cemented or
jointed together, it has been proposed to Mr. Jeffery
to employ his marine glue forthis purpose; but,
from. a Report made to the Admiralty, by a board of
Dock-yard Ofiicers, in 1843, it appears that this glue
is even z‘oo good for the purpose; if any part of a
must decays, it is customary to take themast to pieces,
and re-employ all the sound pieces; but it was found
that a mast which had been formed by the aid of the
marine glue was'with such difliculty separated, that
the pieces were scarcely available again. The marine
glue also constitutes an excellent substance for pitch-
ing or paying the seams of ships. An inferior but
strong marine, glue is formed by simply dissolving
shell-lac in naphtha. . .
We next proceed to notice a few points connected
with the chemistry of wood. - '
When fine saw-"dust is‘boiled, fn'st-in alcohol, then
in water, next in a weaksolution of potash, after-
wards in dilute muriatic acid, and lastly, several times
in distilled water, so as completely to remove all the
soluble portions; the substancewhich remains when
dried at 212° is called lig'm'rz ,- it forms the skeleton
of plants and the basis of their structure; it varies in
texture from delicate pith to the hard shells of seeds:
it forms the bulk of such manufactured products as
linen, cotton, and paper, and the washed and bleached
fibre of hemp or flax is a good example of it. Pure
lignin has a specific gravity of 1'5 : it is white, taste-
less, and is not soluble in water, alcohol, ether, or
oils. v -
In Sweden and Norway saw~dust is sometimes con-
verted into bread, for which purpose beech, ‘or some
wood that does not contain turpentine, is repeatedly
macerated and boiled in water, to remove soluble
matters, and is then reduced to powder, heated seve—
ral times in an oven, and ground: in this state it is
said to have the smell and taste of corn-flour. It has
a yellowish colour, and ferments on the addition of
leaven, the sour leaven of corn'fiour answering best
for the purpose. When well baked, it makes a uniform
and spongy bread. By boiling wood-flour in water, a
thick nutritious jelly is formed, like that made with
wheat-starch.
Lignin is chiefly employed in nature in the organi-
zation of cells and-vessels, and the-solid parts of all
plants. It must be distinguished from lzlgaeoas or
woody tissue, which consists of cellulose together with
other substances which encrust the walls of the mem-
branous cells and give stiffness to the plant. When
VOL. II.

woody tissue has been repeatedly boiled in water and
alcohol, so as to get rid of colouring matter and resin,
it is found to contain an excess of hydrogen above
that required to form water with its oxygen, and it
also contains a little nitrogen. Pure cellulose is a
ternary compound of carbon with the elements of
water, and is said to be isomeric with starch, CmHwOm.
Hence, wood appears to be composed of two parts;
first, lignin, which forms the walls of the'vegetable
cells, and, secondly, cellulose, which fills the cells and
forms an incrustation on their walls. Lignin dissolves
in strong nitric. acid; cellulose remains undissolved.
Sulphuric acid dissolves cellulose, without blackening
it, and converts it into a nearly colourless adhesive
substance, soluble in water, and agreeing in its cha-
racters‘ with, dextrine. Lignin, separated from cellu-
lose, is said to contain C35H24025. The action of nitric
acid on lignin is more particularly noticed under GUN~
COTTON. . < ._ - _ y.
The conversion of cellulose into dextrine is the
fundamental fact in the process of converting old rags
into more than their weight of sugar. This is one of
those marvels of chemistry which has taken posses-
sion of the popular mind, and it may be well to notice
it further in this place, and to state that, however
valuable this fact is in a scientific point of view, the
materials are too costly, and the process is too tedious,
to make it commercially valuable; although we have
seen, under the article GUM, that dextrine or British
gum is made ona large scale for _the purposes of the
manufacturer. To make sugar from old rags, concen-
trated sulphuricacid is to be slowly added to half its
weight of lint ,or linen, ‘in, small pieces, carefully
avoiding any rise in temperature, which would pro-
duce charring or ‘blackening. When the‘ proper
quantity of .acid ‘has been added, the mixture is tritu-
rated in a mortar and left to stand for a few hours.
It is next rubbed up with water, warm ed, and filtered,
in order to separate any small portions of insoluble
matter that may be present. The solution may
now be neutralized by means of chalk, and again
filtered. The gummy liquid contains lime, partly
as sulphate, and partly. in union with .a peculiar
acid, the salpfiolz'grzz'e, which is composed. of the
elements of sulphuric or hypo—sulphuric .‘acid, in
combination with those of lignin. If the liquid,
before'it is neutralized, be boiled for three or four.
hours, and the. water be replaced as. it evaporates,
the dextrine becomes entirely changed into grape~
sugar. .
Wood isvery valuable as a fuel: the excess of hy-
drogen contained in it which, in burning and form-
ing water, requires for equal weights three times as
much oxygen as the carbon does in forming carbonic
acid, gives out in burning nearly four times more
heat than the carbon.
. The chemical changes required for the conversion
of wood into coal are noticed under COAL.
When wood is subject to destructive distillation, a
number of complicated products are formed, varying
with the nature of the wood and the temperature. If
the wood contain resin, some of those substances
3 u
10%
WOOD.
described in the process for making resin gas [see
Gas] will pass over. If the wood contain azotised
principles, ammonia will he formed. If the object of
the distillation be chiefly for the sake of the charcoal,
white woods are placed in iron retorts, which are
gradually heated to redness. The volatile products
consist of gases and vapours: among the former are
carburetted hydrogen, carbonic acid, carbonic oxide,
&c. The vapours condense into liquid or solid pro-
ducts; some of the liquids are soluble in water, such
as flyrocylz'c spirit, pyroligneous acid, &c., and the
insoluble products forming tar and certain oily sub-
stances. [See Tunrnnrmn]
. The pyroxylic or wood-spirit thus obtained is'an
important substance. It resembles alcohol in its
aifinities, forming an ether and a series of compounds
exactly corresponding with those of the vinous spirit.
Like alcohol, wood-spirit is regarded as a hydrated
oxide, of a body corresponding with ethyle [see
Errrnn] ; and which, like that body, has not been
isolated; it is called meflzyle (from ,uniflv wine, and
6%; wood); it contains C2113, and its symbol is ME.
The following table contains a few of the compound
methyle ethers, and the resemblance between this
table and the one given under ether will appear very
striking z—- _
WOOD-SPIRIT .SERIES.
Methyle C,,H3
Oxide of methyle .. C2H8,O
Chloride of methyle CQHMCI
Iodide of methyle .. C,,H,,,I
Woodspirit C,H,,O+HO
Sulphate of oxide of methyle ....... .. C,,H,,,O+SO8
Nitrate of oxide of methyle ....... .. C,,H,,,O+NO5
Sulphomethylic acid CQHSO,ZSO,,+HO
Formic acid CQHOS
Chloroform C,,HCI3
Hydrated oxide of met/Lyle (Me O + HO). Pyroch'o
or wood-spirit‘ is contained in the acid liquor or wood-
vinegar produced by the distillation of wood, and
is separated by distillation, the first portions which
pass over being set aside. The acid liquor does
not probably contain more than one per cent. of
the spirit. A portion of the acid liquor of course
comes over with the spirit, and this is neutralized
by means of hydrate of lime, and the clear liquor
separated from the oil which floats on the surface,
and from the sediment at the bottom of the vessels,
and is again distilled. _In this way is procured a
volatile liquid which burns like weak spirits of wine;
but it may be strengthened like ordinary spirit by
rectification, and made pure and anhydrous by dis—
tilling it from quick-lime at the heat of a water-bath.
When pure, wood-spirit is a thin colourless liquid,
with a peculiar odour, unlike that of alcohol, and it
has a hot disagreeable taste; it boils at 152° F., its
density is ‘798 at 68°, and the density of it's vapour
is 1'12. W ood-spirit mixes freely with water, and,
like alcohol, dissolves the resins and volatile oils, and
is often a cheap substitute for spirits of wine for that
purpose. It may also be burnt in a spirit~lamp,, but
it emits a peculiar odour, which is apt to produce
headache.
Oxide of methyle, MeO, or wood ether, is obtained

by the following process :--One part of wood-spirit
and four parts of concentrated sulphuric acid are
mixed together in a flask, and a gentle heat applied ;
the mixture blackens, and a large quantity of gas is
evolved, which may be passed through a solution
of potash and collected over mercury; this gaseous
substance is the ether in question; it does not liquefy
at so low a temperature as 3° F.; it has an ethereal
odour, and burns with a pale flame. It is soluble to
a certain extent in water, and to a larger extent in
alcohol, wood-spirit, and strong sulphuric acid. Its
density is 1'617.
Ohloroform has been noticed in a separate article.
[See CHLOROFORLL] The interest which attaches to
the other members of the methyle group is purely
scientific. When wood is treated for the production
of pyroligneous acid, or wood—vinegar, about 8 cwt.
of dry hard wood is enclosed in a cast-iron cylinder,
about 6 feet long and d feet in diameter, and set up
on end: the charge of wood is introduced at the
bottom or mouth of the retort, which is then closed by
a cast-iron plate, secured by wedges, and made air-tight
by a clay-luting. To the top is screwed an iron plate,
from the centre of which proceeds a tube for conducting
the products of distillation through a condensing or
refrigerating apparatus, the main tube of which varies
from 9 to 141 inches in diameter, and receives the
products of a number of similar- cylinders. The
cylinders are contained in a furnace which is left to
burn for some hours. About 35 gallons of pyrolig-
neous acid are produced from one charge of wooa:
it is of a deep brown colour, and contains much tar;
its density is 1'025. It is rectified by a second dis-
tillation in a copper still. In rectifying 100 gallons
of the crude acid, about 20 gallons of a thick tarry
substance remain in the still, and the distillate is
a limpid brown vinegar, having an empyreumatic
smell, and of the density of 1013. To purify this
vinegar it is saturated with cream of lime, with which
much of the empyreumatic extractive combines in an
insoluble form; after which the clear solution con-
taining acetate of lime is decanted, and is treated
with a solution of sulphate of soda, which throws
down an insoluble sulphate of lime, while the acetic
acid combines with the soda and remains in solution.
This is drawn off, the sulphate of lime is washed, and
the solution of acetate of soda evaporated to a certain
point, during which a quantity of empyreumatic resin
forms on the surface, and is skimmed oil‘. The solu—
tion is now set aside to crystallize: the mother liquor
is subjected to a special treatment, until it at length
contains nearly all the remaining empyreumatic matter
combined with the soda. It is lastly removed by cal-
cination, and the soda recovered. Any remaining
empyreumatic matters in the crystallized product are
also got rid of by careful calcination, in some cases,
after a second solution and recrystallization. After
the calcination the salt is again dissolved and crystal-
lized, and forms pure acetate of soda, which is dis-
tilled with 0'36 of its weight of sulphuric acid. The
product, which is received in silver condensers, is,
a strong vinegar of the density of 1'05, which, how-
WOOL.
1027
ever, still has an empyreumatic taint, which is finally
removed by animal charcoal. It is diluted with water,
and if intended for the table is coloured with burnt
sugar, and a pleasant odour imparted to it by means
of a few drops of acetic ether. It is used in the arts
as a general substitute for wine—vinegar. It is em-
ployed in pickles and sauces in a stronger state than
common vinegar, and in too many cases the nauseous
empyreumatic flavour (which is removed with so much
difficulty) is but too perceptible.
WOOD ENGRAVING. See Enenxvrne.
WOOF. See Wnnvrne.
TvVOOL. The property of the fibres of wool to
felt or mat together into a kind of cloth must have
attracted notice at an early period. The fitness of
the woollen fibres for spinning into yarn, and for
weaving the yarn into a superior kind of cloth to
that produced by felting, must also have been ob-
served almost as soon as man became acquainted
with wool-bearing animals. The spinning and weav-
ing of wool was well known in the time of Moses;
they were extensively practised by the ancient Greeks
and Romans; and when the latter people made the con-
quest of Britain, they probably introduced these arts
into the island; and the inhabitants thus came gra-
dually to exchange the most primitive form of cloth-
ing—namely, that of the skins of animals caught in the
chase—for a more artificial and more convenient de»
scription of covering. The Romans appear to have
had a factory at Winchester for supplying cloth to
the Roman army. The natives of Britain, however,
adopted the new art very slowly, the peasants con-
tinued to use garments of leather, and did so to
a much later period, for the “ bufi-jerkin ” was in use
among the labouring population at the time of the
Commonwealth.
The first mention of the sheep in Britain occurs in
a public document of the date 712, in which the price
of a sheep is fixed at one shilling until a fortnight
after Easter. We read also that the mother of Alfred
the Great was skilful in the spinning of wool, and
instructed her daughters therein. At later periods the
art of spinning wool was considered part of a good edu-
cation; and the term spinsz‘er, as applied to unmarried
females, indicated the nature of their principal occu-
pation. [See WEAVING.] The origin of the woollen
manufacture as a national employment is supposed to
date from the time of William the Conqueror, when
a number of Flemings, being deprived. of their terri~
tory by an incursion of the sea, came to England and
endeavoured to obtain the patronage of the Queen,
who was a native of their country. In this they were
successful, and they were established under royal
patronage along the northern frontier, in the neigh-
bourhood of Carlisle. Henry I., however, finding
that they did not agree with his other subjects,
removed them to a district taken from the Welsh,
now forming part of Pembrokeshire. Henry II.
granted a fair for clothiers and dressers, to be held
in the churchyard of Bartholomew Priory for three
days-—a spot still designated the Cloth Fair. Towards
the end of this reign the manufacture extended to A

several parts of the kingdom, and companies of
weavers were formed in the counties of York, Oxford,
Nottingham, Huntingdon, Lincoln, and also at Win-
chester, which paid fines to the King for the privi-
lege of carrying on their trade, to the exclusion of
other towns. There were also dealers who paid fines
to the King for permission to buy and sell dyed
cloth. Henry II. confirmed the weavers of London
in their guild, and prohibited the use of Spanish wool
under pain of forfeiture of the goods. The troubles
of succeeding reigns diminished the prosperity of this
trade; but it again revived in the reign of Edward
III., when one Kemp of Flanders was licensed to
settle at Kendal, in Westmoreland, where his descend—
ants are still said to practise the trade of their ances—
tors. The cloth called “Kendal green ” became
celebrated. The success of Kemp led the sovereign
to invite others of his industrious countrymen to
settle in England, and the prosperity consequent on
the extended employment of the poor thereby is a
subject of congratulation in Fuller’s Church History.
We learn that the result of this wise measure, com—
bined with the trade already existing, was—the pro-
duction of woollen fustians at Norwich; baizes at
Sudbury; broad cloths in Kent; kerseys in Devon;
friezes in Wales ; cloths in Worcestershire, Glouces-
tershire, Hampshire, Sussex, and Berkshire; coarse
cloths in the West Riding of Yorkshire; and serges
at Colchester in Essex, and Taunton in Somersetshire.
A celebrated Dutch cloth-maker in Gloucestershire
had the surname of Web bestowed upon him by
Edward III. About this time the use of Fuller’s-
earth in this manufacture was discovered. The
cruelty of the Duke of Alva drove over from Holland
a number of industrious Dutch, who increased the
prosperity of the woollen trade of this country. The
wool trade was the subject of frequent and contra-
dictory legislation during the reign of Edward III.
Alaw was first passed forbidding the exportation of
British wool, and the importation of foreign cloth.
A tax of 208. was levied on every sack of wool em-
ployed in the home manufacture. After some years,
however, at the joint entreaty of the grower and
manufacturer, wool was again allowed to be exported,
and foreign cloth imported on payment of a tax.
British wool at this time was so much esteemed that
it sold at very high prices in foreign markets, and
was often used instead of money; thus, at a time
when gold was scarce, in 134:2, the king sent a large
number of sacks of wool to Cologne, to redeem Queen
Phillippa’s crown, which was pawned there for 2,500l.
As the trade increased, a sworn olficer, called an
alezager, was appointed to inspect woollens, and to
prevent imposition.
Restrictions were again put on the exportation of
wool in the reign of Richard II. These caused great
murmurings, so that the restrictions were removed;
but British wool did not recover its former high
price. Spanish wool began to be extensively em-
ployed in broadcloths, and a peculiar class of goods
called worsted (from the name of a small town in
Norfolk, where they were first made,) also came into
3 U 2
1028
WOOL.
fashion. The taste for long wool, or worsted goods,
led to variations in the growth of wool, and to
changes, if not deteriorations, in the native breeds of
sheep. The long-wooled sheep of this country soon
became celebrated, and the fleece was in much request
abroad. Attempts were also made to export the
animal itself, but this was forbidden by laws passed
in the reigns of Henry VI. and Elizabeth, under very
heavy penalties. This frequent and mischievous legis-
lation on the subject of our staple trade was rendered
ridiculous by the sovereigns themselves being the
first to infringe the regulations respecting the ex-
portation of the sheep. Thus, Edward IV. sent a
present of Cotswold rams to Henry of Castile, and
another flock to John of Aragon. It is also said that
the celebrated breed of Spanish sheep, called jlleirz'rzo,
obtained this name from Mar-mo, because they were
originally imported 123/ sea from England, in the reign
of Henry II. Edward IV. also granted to his sister
Margaret, Duchess Dowager of Burgundy, permission
to export yearly from England, free of all duty, 1,000
oxen and 2,000 rams to Flanders, Holland, and Zea-
land. ‘In-the reigns of Henry VII. and Henry VIII.
the wool trade was in a declining condition; the
British short wool did not maintain its old reputation
either at home or abroad. Still there were a few
celebrated manufacturers, whose wealth and impor-
tance may be judged of by the fact that one of them,
John Winchcombe (better known as Jack of New-
bury), kept 100 looms constantly at work, and fitted
out at his own cost 60 soldiers for the battle of
Flodden Field. . -
The system of monopolies established in the reign
of HenryrVIIL, which restricted the manufacture of
certain articles ‘to particular towns, was very injurious
to the woollen trade. Thus, it was declared by law
that the manufacture of coverlets should be confined
to the city of York, worsted to the city of Norwich.
The manufacturers of Worcester were in like manner
limited to that town, with four others.
The invention or introduction of the spinning—
wheel, about the year 1530, caused some revival of
the woollen trade, towards the end of the reign of
Henry VIII; and in the reign of Elizabeth, the trade
shared in the general prosperity of the kingdom.‘
This judicious sovereign permitted the grower of
wool to select his own market for its disposal, and
left the trade as unfettered as possible, judging cor-
rectly that the various raw and manufactured pro-
ducts would, if left to themselves, become diffused by
natural channels, and thus contribute to the pro-
sperity of the people, and the consequent strength of
the government. In singular contrast with this liberal
policy was that of the Spanish government in the
Netherlands: religious persecution drove from their
country many thousands of industrious artisans, who
sought refuge in London, and various parts of Eng
land, and enriched our land by their skill and in-
dustry ; their improved machines, and superior me~
tliods in the manufacture of wool and silk, enabling
us to send into the market better fabrics than hereto-
fore. There were marked improvements in the manu-

facture of light cloth and worsteds, in which England
had hitherto been deficient; and new markets were
opened for the increased produce.
Although the English were skilful in the weaving and
dressing of cloth, yet the art of dyeing and finishing
it, once well known to them, had been lost amidst the
distractions of the kingdom. It was therefore the
custom to send white cloths into Holland to be dyed
and dressed. In the reign of James I., some English
merchants and manufacturers proposed to undertake
these operations on certain terms, leaving to the king
the monopoly of the sale. This plan was tried, but
did not succeed ; the natural result of the absence of
competition being, that the cloths were badly _dyed,
and the expense. Was greater than that of sending
them abroad, so that the I-Iollanders still continued
to finish our cloths as before. But in the year 1667
a dyer, named Brewer, came from the Netherlands,
with ‘his workmen, and, under the patronage of the
government, instructed theEnglish manufacturers in
his art, so that they soon became independent of the
continent in this respect. During the civil wars of
Charles I. the trade escaped from the hands of the,
English into those of our continental rivals, and
various descriptions of cloth were manufactured by
them which had previously been the sole produce of
England. In order to revive the trade, one of those
absurd laws was passed, which show so much igno-
rance of the principles of commerce on the part of.
the legislature. In 1666 it was enacted that every
person should be buried in a shroud, composed of
wool alone, under the forfeiture of 5!. to the poor of
the parish. This law continued in force about 150
a years. In the year 1685, that most unjust law, com-
monly known as the revocation of the edict of Nantes,
was passed in France, whereby upwards of 600,000
Protestants, being deprived of the liberty of worship-
ping God according to the light of Scripture truth
and of their own conscience, were compelled to expa-
triate themselves. Of this large number, no less than
50,000 sought refuge in England, where they were
well received. Many of them were skilful in the
manufacture of cloth, and improved the lighter tex-
tures, which at that time were in great demand. A
larger supply of fine cloth was produced, a greater
number of sheep were bred, and the trade generally
revived. From that time to the present, the woollen
trade has continued steadily to increase in prosperity.
Some remarkable changes, however, have taken place.
in the supply of the raw material. The system of
turnip husbandry was found to be highly beneficial to
the rearing of sheep, for by its means a. regular supply
of food was secured to the flocks at all seasons. The
increased demand for wool was thus met by a large
increase in the number of sheep,.whicl1 had risen from
12,000,000 in 1698, to 32,000,000 in 1833. It was
found, however, that the fattening, and increased
growth of theanimal, consequent on the new system
of husbandry, was not favourable tothe texture of
the wool; for as the sheep increased in size, the fibre
of the wool became longer and coarser. Thus the
goods manufactured from it became deteriorated in
WOOL.
1029
quality, and ceased to find a sale in their accus-
tomed markets. By'a natu-ral reaction, the farmer
could no longer sell his wool, and he soon complained
loudly against the Spanish and other foreign wools
which the manufacturer preferred to his own. As the
government of this country has ever been disposed to
lend an attentive ear to the complaints of the land-
owner, British wool was accordingly protected, al-
though that protection involved the ruin of the
woollen-cloth manufacturer, and consequently of the
wool-grower. This result was happily prevented by
the discovery that British wool, although changed in
character, had acquired properties which eminently
fitted it for another branch of the trade. The wool
had no longer that short fibre which fits it for carding,
but a long fibre which well adapts it for combing; so
that if no longer fitted for the manufacture of broad-
cloth, it was well adapted to that of worsted. On
this discovery, the government removed the fetters
which had so long and so variously impeded this
branch of industry. In the course of years an impor-
tant export trade arose in British wools and worsted,
while the imports of wool from Spain and Germany
rose from 3,000,000 lbs. in 1800, to 91,692,86dlbs. in
1852; while the introduction of cotton machinery, in
a modified form, was of great importance to the
manufacturing processes.
Wool is defined by Professor Owen to be “ a pecu-
liar modification of hair, characterised by fine trans-
verse or oblique lines, from 2,000 to 4:,000 in the
extent of an inch, indicative of a minutely imbrioated
scaly surface when viewed under the microscope, on
which, and on its curved or twisted form, depends its
remarkable felting property, and its consequent value
in manufactures.” Wool is not peculiar to the sheep;
but forms a sort of under coat, beneath thelong hair,
in the goat and many other animals. The Argali, or
wild sheep of Siberia and Kamtschatka, has a summer
coat of hair, sleek as that of the deer; but in winter,
a woolly variety of hair is developed in excess, and
the under coat is also of a fine woolly down. In the
domestic sheep the fleece has been- greatly improved
and modified by circumstances of climate, pasture,
shelter, and judicious crossing of - breeds, by which
many varieties of wool have been grown, chiefly
divisible into the two great classes of car-‘(Zing wool
and combing wool. The occurrence of hair in the
fleece of the domestic sheep is now rare and is con-
sidered as indicative of bad management; but if sheep
are left to themselves on downs and moors, there-is a
tendency to the formation. of hair among. the wool.
,Change of pasture has a marked influence on the
quality of the wool: if sheep that' have been fed on
_chalk downs ‘be removed to richer pastures only a .
month before shearing, a remarkable improvement
will take place in the fleece. So also sheep that
occupy lands within a few miles of the sea will pro-
duce a longer and more pliant wool than that of sheep
from more inland districts. Wool varies in quality,
in the same flock, at different times. When the sheep
is in good condition, the fibre is brilliant; but in
badly fed or diseased sheep the wool is dull and

dingy, and when out from the dead animal it is harsh
and weak, and takes the dye badly. In commerce
wools are distinguished as fleece wools and dead
wools—the first being obtained from the annual
shearings, the second from the dead animal.
The once celebrated merino wool, is obtained from
the migratory sheep of-Spain. Some years ago, it
was calculated that the number of these migratory
sheep amounted to 10,000,000. Twice a year, in
April and October, they are led ajourney of about
400 miles, passing the summer in the mountains of
the north, and the winter on the plains towards the
south. The excellence of the wool, to which every-
thing else is sacrificed, is supposed to be due to an
equality of temperature maintained by shifting the
position of the sheep, so that they may occupy the
cooler. mountains in summer, and the warmer plains
in winter. An- objection to this explanation arises
from the fact, that the fleece of some of the German
merinos, which do not travel at all, is far superior to
the best Leonese fleece; and, even in Spain, it is said
that there are stationary flocks which produce wool
equal in quality to that of the migratory ones. The
first impression- made by the merino sheep, on one un-
acquainted with its value, would be unfavourable. The
wool’ lying closer and thicker over the body than in
most other breeds of sheep, and being abundant in
polls,‘ is covered with a dirty crust, often full of cracks.
There is also a coarse and ugly patch of hair on the
forehead and cheeks‘, which is cut away before shear-
ing time. There is also a singular looseness of skin
under the throat, giving a remarkable appearance of‘
hollowness in the neck. The pile, when pressed upon,
is hard and unyielding, in consequence of the thick-
ness with which it grows on the pelt, and the abun-
dance of the yolk detaining all the dirt and gravel
which fall'upon it;-but when examined, the fibre is
found to exceed in fineness, and in the number of
serrations and curves, that: which any other sheep in
the world produces. The average weight of the fleece
in‘ Spain is 8lbs. fromthe ram, and 5lbs. from the
ewe. “ The excellency of the merinos consists in
the unexampled fineness and felting property of their
wool,_and in the weight of“: it yielded by each indivi—
.dual sheep ;. the closeness-of that wool, and the luxu-
riance of the yolk, which enables’ them to _ support
extremes of cold and wet- quite‘- as well as any other
breed ; the easiness with which they adapt themselves
to every change. of: climate, andthrive and retain, with
common care, all their fineness of. wool under a burn-
ing tropical sun, and in the frozen regions of the
north; an appetite which renders them apparently
satisfied with the coarsest food; a quietness and

(1) The yolk is a peculiar secretion'from the glands of the skin,
and serves to nourish the wool,- and by matting the fibres toge-
ther forms a defence against wet and cold. It exists in greatest
quantity about the breast and shoulders, where the best wool is
produced. It differs in quantity in different breeds; but the
medium quantity is about half the fleece, and this allowance is
made to the buyer, when the wool is sold without having pre-
viously been washed. The yolk is a true soap, and is soluble in
water ; hence the practice of washing sheep previous to shearing.
If the yolk be left in the fleece it is apt to ferment, and to make
the wool hard and harsh.
1030
WOOL.
patience into whatever pasture they are turned, and
a gentleness and tractableness not excelled in any
other breed.” 1
The periodical journeys taken by these sheep in
Spain can be traced back to the middle of the 14th
century, when a tribunal, called the Mesta, was esta-
blished for their regulation, consisting of the chief
proprietors of these migratory flocks, the king being
the merino mayor. It established a right to graze on
all the open and common land that lay in the way; it
claimed also a path, 90 yards wide, through all the
enclosed and cultivated country, and prohibited all
persons, even foot passengers, from travelling these
roads when the sheep were in motion. The flocks are
divided into detachments of- 10,000 each, under the
care of a mayoral or chief shepherd, who has under
him 50 shepherds and as many huge dogs. The
mayoral precedes the flock, and directs the length
and speed of the journey; the others, with the dogs,
follow and flank the cavalcade, collect the stragglers,
and keep off the wolves, which regularly follow at a
distance and migrate with the flock. ‘A few asses or
mules carry the clothing and other necessaries of the
shepherds and the materials for the fold at night.
Several of the sheep are perfectly tamed, and taught
to obey the signals of the shepherds. These follow the
leadingshepherd—for there is no driving—and the
rest quietly follow them. The flocks travel through the
cultivated country at the rate of 18 or 20 miles a-day;
but in open country, with good pasture, more lei-
surely. Much damage is done to the country over
which these immense flocks are passing; the free
sheep—walk, which the landed proprietors are forced
to keep open, interferes with enclosure and good hus-
bandry: the commons also are so completely eaten
down that the sheep of the neighbourhood are for a
time half-starved. The sheep know as well as the
shepherds when the procession has arrived at the end
of its journey. In April their migratory instinct ren-
ders them restless, and if not guided they set forth
unattended to the cooler hills. In spite of the vigi-
lance of the shepherds, great numbers often escape.
If not destroyed by the wolves, there is no danger of
losing these stragglers, for they are found on their
old pasture quietly waiting the arrival of their com-
panions. -
It is during this journey that the sheep are shorn,
and the shearing time is an epoch of primitive oriental
festivity. Buildings are erected at various places in
the early portion- of their journey: they are very
simply constructed, consisting only of two large rooms,
each of which will contain more than a thousand sheep ;
there is also a. narrow, low, long but adjoining, called
the sweating-house. The sheep are all driven into one
of these apartments, and in the evening those intended
to be shorn on the following day are transferred into
the hut. As many are forced into it as it will possibly
hold, and there they are left during the night. In
consequence of this close confinement they are thrown
into a state of great perspiration; the hardened yolk

(I) Youatt on “ The 'Sheep.”

is melted, and thus the ‘whole fleece, by being ren-
dered softer, is more easily out. There is no previous
washing nor any other preparation for the shearing.
From 150 to 200 shearers are generally collected at
each house, and a flock of 1,000 sheep is disposed of
in a day. The sheep are turned back, as they are
shorn, into the second apartment, and on the same or
the following day continue their journey. Thus in
the space of six days, as many flocks, each consisting
of 1,000 sheep, pass‘ through the hands of the shear-
ers. The wool is then washed and sorted, and is ready
for sale. The rams give most wool: three fleeces often
averaging 25 lbs. When the sheep arrive at their sum-
mer pasture, salt is placed on flat stones, at the rate
of about a hundred weight for every 100 sheep; this
they lick eagerly, and it improves their appetite.
They are always on the move in search of grass,
which is scarce, for they will not touch thyme, which
is abundant, and is left to the wild bee. They are
never fed until the dew is dry, nor allowed to drink
after hail-storms. In September the flocks are daubed
with a red earth, which is said to conduce to the fine-
ness of the wool. After their return in October the
yea'ning time approaches. The Merinos are not good
nurses, so that nearly half the lambs, and in bad sea-
sons, when the pasture fails, full three-fourths, are
killed as soon as they are yeaned. The skins are sent
to Portugal, and from thence to England, where they
are used in the glove manufacture. The wool is soft
and silky, and is formed in little rings or curls. March
is a very busy month with the shepherds, who then
cutoff the tails of the lambs and the tips of the horns,
that they may not hurt each other in their frolics; the
shepherds also mark them on the nose with a hot iron.
Forty or fifty thousand shepherds are said to be em-
ployed in tending these sheep. They are a singular
race of men, almost as simple as their sheep. Their
talk is almost entirely confined to rams and ewes;
they know every one of the sheep, and the sheep know
them. They live chiefly on bread seasoned with oil
or grease ; and though they sometimes procure mutton
from their old or diseased sheep, it is not their fa-
vourite food. Their dress is a jacket and breeches of
black sheep-skin; a red silken sash tied round the
Waist ; long leathern gaiters; a slouched hat; a staff
tipped with iron; and a manic, or brown blanket, slung
over the left shoulder. When they have reached their
journey’s end, they build themselves rude huts, living
generally a single life.
About the year 1765 the merino sheep was intro-
duced into Saxony, and after some years became
naturalised there: the breed. of Saxon sheep was also
improved by crossing, and after some years the Saxon
fleece was found to be superior to the Spanish in fine-
ness and manufa'cturingvalue. ' _ ‘
In France the growth of wool has not been carried
‘on with much success: sheep‘ are numerous in the
south, but the wools ‘are long and coarse. In Sweden,
Denmark, Prussia, and ' some other countries,‘ the
native breeds’ of‘ sheep have been improved by the
introduction of merinos; and so successful “has this
plan been in Hungary, that the fleece of that country
WOOL.
1081
has rivallcd that of Siberia and Saxony, and excelled
the Spanish merino.
In the year 1787 a small flock of merinos from the
borders of Portugal was received in England, but as
they came from different districts, and were not
uniform in character, no experiment was made with
them. Application was made by George III. to the
King of Spain, for permission to select sheep from
one of the best flocks : this was granted, and a num—
ber of sheep of the valuable Negrette breed, which
the law of Spain had hitherto prevented from being
exported, arrived in England in 1791, and were trans-
fer-red to Kew. In this, as in other cases, the experi-
ments were successful. After a few crossings on the
Wiltshires, the ewes became hornless ; they had
acquired the shape of the merino, the wool had in—
creased from lit-lbs. to nearly filbs. per fleece, and
was scarcely inferior to that of the pure Spanish
sheep. In England, however, as in other countries,
the prejudices of the wool-grower opposed most
serious obstacles to the diffusion of the merino. By
the exertions, however, of scientific men, and the arti-
ficial stimulus of a “ Merino Society,” with Sir Joseph
Banks as its president, with fifty-four vice-presidents,
local committees in every county, public dinners and
after~dinner speeches, the Negrette flock was regarded
with favour and even with enthusiasm. At a public
sale of merinos in 1810, a Negrette ram was sold for
173 guineas. All, however, would not do. The farmer
found that it was more to his interest to grow mutton
than to grow wool, and the system of artificial feed-
ing enabled him to send his sheep to market within
a comparatively short space of time; whereas the
merinos fattened slowly, and were long in arriving at
maturity. The increased value of the wool did not
compensate for this disadvantage, and it was found
that the finer foreign wool could be purchased at a
cheaper rate than it could be grown in this country.
The introduction of the merino into Australia was
eminently successful. New South Wales had originally
been supplied with sheep from Bengal, for the purpose
of furnishing the colonists with mutton and wool, and
of establishing a permanent flock; the climate was
favourable to these sheep, but the fleece was coarse
and hairy. They were much improved by the South-
down and Leicester varieties, and in a short time
both the fleece and the carcase had doubled in value.
In the year 1800 there were only about 6,000 sheep
in the whole settlement. Shortly after a few merinos
were 'imported from England, and the wool of the
mixed breed was found to be equal to that of the
pure merinos in Europe, while the wool of the pure
breed also improved. The number of sheep rapidly
increased; in 1813 it was upwards of 65,000; in 1817
it was 170,4:20; and in 1828 it was 536,391. As
the fleece of the merino had become finer and softer
in New South Wales, it was supposed that Saxony
wool might be improved by transplantation. Accord-
ingly some sheep were imported from Germany, and
after a fair trial it was found that if the Saxon fleece
had not been improved, it was superior to any that
the colony had hitherto possessed. Australian wool

is said to possess an extraordinary softnessi'and silki-
ness, and spins well. The first importation of wool
from New South Wales into England in 1807 was
24151bs.: in 1848 it amounted to 23,000,0001bs.,
of the value of upwards of 1,200,000Z.
In the Great Exhibition, Germany retained its pre-
eminence for fine wool. The fleeces exhibited by
Messrs. Eigdor and Sons, from Austria, presented in a
high degree “the desired qualities of substance in
the staple, and of fineness and elasticity of the com—
ponent fibres, the spiral curves of which were close
and regular, and were immediately resumed after
being obliterated by stretching the fibre—the length
of which was also considerable for wool of this card-
ing quality, the most valuable for the finest descrip-
tions of cloth.”1
The worsted trade, although ancient-,2 did not begin
to assume its present importance until about twenty
years ago. The introduction of cotton machinery
into this branch of manufacture took place towards
the end of the last century; but up to the year 183&
worsted fabrics were made of wool alone, with the
exception of bombazines and mixed fabrics manu-
factured in Norfolk; but at that time manufactures
of worsted weft and cotton warp were first brought
forward, and gave a great impetus to the trade. In
1836 the wool of the alpaca, an animal of the llama
tribe inhabiting the mountain ranges of Peru, was
introduced: this wool is of various shades of black,
white, grey, brown, 850., and is remarkable for bright—
ness and lustre, great length of staple, and extreme
softness. After the diificulties of working this ma-
terial had been overcome, the alpaca manufacture
assumed an important rank in the worsted trade.
About the same period, mohair, or goat’s wool, from
Asia Minor, came into general use in the West Riding
of Yorkshire, and many beautiful fabrics were pro-
duced from it. The combination of silk with these
new materials has led to the production of many
beautiful fabrics for clothing and furniture; more
rapid processes of manufacture have been contrived,
improved machinery has been and is being constantly
produced; and yet, notwithstanding the greatly in-
creased facilities of production, the number of work-
people employed has been quadrupled during the
last thirty years. Thus, Bradford, which is the centre
of the manufacture, and the great market of this
trade, had, in 1821, a population of 26,309; in 1831,
453,527; in 1841, 66,718; and in 1851, 103,782.
At the commencement of the present century there
were only 3 mills in Bradford, and there are now
upwards of 160.
Sncrron I.-— *uraornnn or Bnonn Cnorn.3
Wool grown in England is but little used in the

(1) Jury Report, Class IV. Part ii.
(2) The invention of the wool-comb is assigned to St. Blaise;
and the 3d of February, being the day of his canonization, was,
until lately, kept as a festival in Bradford, and other parts of
England.
(3) We are indebted for most of the details of this section to
T. B. W. Sheppard, Esq., who has kindly furnished us with an
outline of the processes, as carried on at the factory of the
Messrs. Sheppard, of Frome, Somerset.
1032'
WOOL.
standard trade, 2'. e. the ordinary broad cloth manu-
facture. The principal demand for English wools is
for fiannels and coarse cloth, such as that used for
coachmen’s great-coats. The three varieties of wool
principally employed in the manufacture of broad
cloth are the German wool, the Australian, and the
Cape wool. There are other wools which are more or
less used, such as those from Odessa and New Zealancl.
German wool is the finest, and is used either alone or
mixed with other wools for all the finest descriptions
of cloth. Australian wool is divided into several
varieties, the names being derived from the parts of
the colony from which they are exported. Sgolneg
wool is a good useful wool for common purposes, and
obtains a price in the markets, from ls. 4a. to Is. 10el.
per lb. Cape wool, from the Cape of Good Hope, is
an inferior wool to the Australian, being usually
much shorter in the- staple, and more wasting or
srnnelgg, as it is termed. -
Wool comes to the English market in various
states. Wools in the grease are such as have been
shorn from the sheep in the natural yolk and dirt, and
have not had anything else done to them. Hand-
was/zecl wools are such as have been taken from sheep
which have been previously washed in running water.
Sronrecl wools have been scoured and cleansed after
being shorn, and these fetch the highest price in the
market; but the German is of course more valuable
than scoured Sydney. In purchasing wools, several
points have to be considered in order to determine
the value : the first great requisite is fineness of fibre,
without which it is impossible to produce a fine cloth;
sofi‘ness is also an important quality, as much of the
felting property of wool depends upon it. There
must also be a ‘certain length of fibre or staple;
because, if this be too short, the wool will not spin
‘out'to the required degree of fineness. Length of
fibre, however, is not of so much importance in wools
for broad cloth as in those that are to be employed
for making worsted goods. In estimating the quality
of wools, the waste must also be considered. Few
wools waste less than 3lbs. per score, and some as
‘much as 13 or 14: lbs. The purchaser has to con-
sider the cleanliness of the wool and the quantity
that it will waste in the various processes of manu-
facture, and must regulate his price accordingly.
Greasy wools generally waste half their weight, and
only fetch half the price that the same wools would
if in handwashed condition. Various seeds become
mixed with the wool, from the sheep rubbing them-
selves against bu'shes, &c. Of these, those known as
burrs are the most detrimental, as it is very diflicult
to get them out of the wool, to which they attach them-
selves with such tenacity, that they actually become
drawn out with the spun thread and woven in with
the cloth. _Other seeds, called melts and Izarol/zeacls,
are not so much to be guarded against as the former;
but still, when present in any quantity, they are suf-
ficiently prejudicial to lower the value of the wool.
The great proportion of colonial wool is sold in Lon-
don at quarterly sales, which were, till lately, held
in the Hall of Commerce, in Threadneedle Street, A

but now take place in a building erected for the pur-
puse in Moorgate Street, and are'attended by buyers
from all parts of the United Kingdom. The wools
are put up in lots of from 1 to 8 or 10 bales, each
bale or bag weighing from 2 to 3 cwt., or more.
The wools of each day’s sale are exposed to view at
one or other of various large warehouses devoted to
this purpose. The corner of every bag is cut open,
and the lots are all marked on the bags. The buyer
having his catalogue with him, examines and puts his
valuation against the lots, and thus prepares for the
sale, which commences at about four o’clock. The
advance at each bidding is gel, and the bidding is
often very spirited. The following were the prices
per lb. obtained for the various wools at the sales of
March, 185st :-—-
t
s. d. s. d. d. s. d.
Sydney Fleece 1 6 tel 10 Grease 7 to 0 11>}
Scoured Sydney 1 10 to 2 2
Port Phillip........ 1 7 to 1 9,1; Grease 7% to 1 1 l
Cape................ . 1 3 to 1 7 Grease 7 to 1 Oi;
Sorting—After the bags of wool have been deli-
vered at the manufactory, the first process which they
undergo is that of sorting, or dividing into various
qualities. This is an operation that requires great
delicacy of touch and skill. The sorter, having opened
the bag, takes each fleece, and lays it open before 'him
on a table, sometimes formed of horizontal bars of
wood, fastened together so as to form a sort of open
framework, through which loose dirt can fall. The
sorter divides the W001 into various qualities, accord-
ing to the fineness of the fibre. Three sorts, called
respectively, _Prz'rnes, Seconds, and T/n'rels, are generally
sufficient for use.1 When a certain quantity has been
sorted, the sorter makes it up in loose bags, called
sheets, ready to be sent to the dye-house.
Securing, Dgez'ng, Wz'llowz'ng, ancl Oz'lz'ng—Before
the wool is ready for dyeing, it requires to be secured
or washed, to get rid of the animal grease. This is
done at the dye—house, with stale urine, heated to
about 120°, and which is afterwards washed out in
running water. The wool is now fit for dyeing, or it
may be deferred until the cloth is woven: in the
one case the cloth is said to be wool-elgecl; and in
the other piece—algal. [See DYEING—INDIGO, 850.]
It should, however, be stated that in the produc—
tion of a black dye, the wool is boiled with bi-chro-
mate of potash, and a small quantity of sulphuric
acid; then washed in water, and treated'with logwood,
by which means a fast and solid black is produced.
Instead of using logwood other dye-stuffs may be
taken, by which means various other colours may be
produced in a similar manner, for the oxide of chro-
mium in the wool acts like alumina or per-oxide of
iron in attaching colouring matters. ' In the Great
Exhibition, Mr. Grune of Berlin exhibited prepared
colours containing the mordant, by which it was
stated that wool could be dyed‘at one operation with-

( 1) Eight or ten divisions or sorts are sometimes made out of a
fleece: these are called prime, choice, super, head, downrights,
seconds, fine abb, coarse abb, livery, short coarse, or breech wool.
The prime sort sometimes furnishes a few remarkably fine locks
known as pick-looks. -
WOOL.
1033
out boiling. Some samples of well-dyed wool, illus-
trating the process, were also exhibited.
After the wool is dyed it is passed through the
Tzm'lly Devil or Tucker,1 which consists of a large
wooden cylinder having strong iron spikes, about 3
inches long, projecting from it, in a spiral direction
round its circumference; this cylinder is enclosed in a
wooden case, and the wool, supplied to it from an
endless web or feeding-cloth, and passing between
feeding-rollers, is exposed to the action of the spiked
cylinder, which, revolving with great rapidity, tears
apart the fibres of the wool and makes it Izollow or
light and open, at the same time allowing any dust or
dirt to fall through a grating beneath. After this, it
is necessary to pick over the wool in order to remove
seeds, pieces of string, or other substances, and locks
of wool of a different colour which have either not
quite taken the dye, or belong to other lots of wool.
This operation is performed by women, who sit before

a low table, the top of which is formed of open wire-
work, so as to allow dust to fall through; they ex—
amine all the wool, shake it open, and pick out all
foreign substances. A good picker can pick about
201bs. of wool per day. The expense and trouble of
this process led to the invention, by Mr. Sykes, of
Huddersfield, ‘of the woolpz'c/cz'ng and cleaning mac/zine,
also known as the Barring Mac/tine, its great use
being to free burry wool from the burrs, and it
answers the purpose so well as to be gradually super-
seding the picking by hand.
The section, Fig. 2375, shows the principal working
parts of the machine; A is the feed-cloth by which
the wool is carried into the machine; a a are two
fluted iron rollers which draw in the wool, and it is
then exposed to the action of a heavy iron beater, B,
which, rapidly revolving in the direction of the arrow,
beats and separates the wool and throws it down on
the cloth D, while dust and dirt pass through the

WOO L—PHIKING
Fig. 2375.
grating o. The cloth D has a chain fastened to each
side, the links of which work into studs on the
rollers 05 d, thus ensuring regularity of motion; the
loose wool is carried forward by this cloth under the
wire cage E, which pressing upon it forms, it into a
loose lap or fleece: this is taken off the cloth by the
brush r, and transferred by it to the comb cylinder K.
This cylinder consists of a number of fine iron combs,
set longitudinally round the circumference of a cir—
cular wheel: by the revolution of this cylinder it is»
carried on to the card roller G, which takes it OK the
comb cylinder, and is itself stripped by the brush H,
the latter returning the wool to the large cylinder,
which then carries it forward to 0. At 0 there is a

(1) The word willy, or twilly, is a corruption of the willow of
the cotton manufacture, and this again is probably a corruption
of winnow, the action of the machine being to separate impurities
from the wool; but, according to some authorities, the first willow-
ing machine was made of willow-wood, whence the name.

AND CLEANING MACHIN E.
steel blade or straight-edge placed vertically at _a very
small distance from the comb cylinder; the latter
draws the wool through the narrow slit, but every
burr, seed, or other foreign substance, is stopped by
the plate 0. A roller, Z, covered with spiral blades,
(similar to those used in the cutters) revolves against
the plate 0. This comes in contact with every burr, &c.,
that has been stopped bythe plate, and knocks or throws
it, with the lock of wool to which it is attached, back to
the cylinder M, the short projecting points on which
throw it back over the bars m of a grating to a
small fluted wooden roller N, which finally throws
back the lock of wool (from which generally the burr
has now been detached) down the sloping board n on
to the feedecloth, where it passes into the machine
with the other wool. The wool which has passed the
opening at o is carried on by the combs till it is
stripped off by the brushes fixed on the angles of a
large square bar or prism L, which throw it out into
1033-1
WOOL.
the room. This machine not only cleans the wool,
but opens it, and renders it light and hollow, thereby
fitting it for the scribbling process. It thus prepares
about 50 lbs. of wool per hour.
After the wool has been picked, it is oiled previous
to passing through the Scribbler and Carder. In order
to do this, the wool is spread out on a stone floor, in a
layer, to the depth of 6 inches or more. Either galli-
poli or pahn-oil is then sprinkled over it, by hand or
by a kind of watering-pot ; then another layer of
wool is added, which is oiled as before, and so on in
successive layers until the whole quantity of wool
which is to be operated upon has been thus treated.
From 3 to dlbs. of oil are used to every twenty
pounds of wool; the wool is again passed through the
Willy or Tucker, in order to mix the oil and wool
thoroughly together. If the wool is picked by the
Burring Machine, it is oiled previous to passing
through it.
Scrz'bdlz'ng/ and Oardz'rzgr-The wool is now ready
for the scribbler, which is very similar in principle to
the Carding Engine described under Co'r'roN, Figs.
638 to 64%. Scribbling, however, is a coarser pro-
cess than carding, and its object is to form the oiled
wool into a broad thin fleece, or lap, in which the
fibres are opened’ and separated. The wool goes
through the scribbler always twice, sometimes three
or four times, so that the fibres may be completely
disentangled and separated. It is carded only once.
The wool-carding engine diti'ers somewhat from the
cotton-carding engine. The fibres of wool being more
twisted, elastic, and stiff than those of cotton, require
the carding apparatus to be so arranged as not only
to open the wool without breaking it, but also to
make the fibres cross each other in all directions.
The wool-carding engine consists of large cylinders
or card-drums, surmounted by smaller cylinders called
urchins, all covered with carding wires. The smaller
cylinders, which are arranged in pairs, are of unequal
size; the larger of the two is called the worker, and
the smaller the cleaner: these revolve at great speed.
At one end of the engine is an endless feeding-cloth,
upon a certain length of which a given weight of the
oiled wool is spread evenly by hand. This delivers
the wool through a pair of feeding-rollers, which dis-
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Fig. 2376. WOOL-CARDING.
gradually stripped by the first worker, whence it is
received by the first cleaner, and by it again deposited
in the large card-drum. When it has passed over the
last cylinder into the drum, -it is taken from it by a
dotfingpcylinder; from which the wool is removed by

a steel comb, or dofiing-knife, moving rapidly up and
down. The doifing-cylinder is not entirely covered
with wires, but merely with a succession of card
leathers, arranged in straight bands, parallel to its
axis, with spaces between every two bands. The
efl’ect of this arrangement is, that the dofling-knife
removes the wool in the form of separate slivers, each
the length of the doifing-cylinder, and these, instead
of being wound upon a roller, fall into the plates of a
plated cylinder, called the roller-bowl, which, being
partly covered with a case or shell nearly in contact
with it, the slivers are rolled into cardings, and are
received upon an apron at the opposite end of the
machine. The cardings are weighed from time to
time, to see that each contains the proper quantity of
wool.
Sludtz'rzgr—The rovings produced by the carder are
the first commencement of the thread, though they
possess little or no strength, being only held together
by the interlacing of the fibres of the wool. In order
to give strength, they require to be twisted. Some
time after the introduction into the cotton manufac-
ture of the Spinning Jenny, (see COTTON, Fig. 629,)
an attempt was made to employ a similar machine in
the preparation of woollen rovings, or slubbz'ngs as
they are called, and which had previously been pro-
duced by hand on the spinning-wheel. The attempt
succeeded, and the machine, under the name of the
Sludtz'rzg-Bz'lly, continues still in use for preparing
the slubbings which are afterwards to be spun by the
mule. The Slubbing-Billy consists of a wooden frame,
within which is a carriage capable of being moved
upon the lower side rails, through a space of several
feet, called the billy-gate, from one end of the frame
to the other. This carriage contains a number of
spindles, which are made to rotate rapidly by a series
of cords passing round the pulley of each spindle, and
connected with a drum extending the whole breadth
of the carriage, to which motion is given by the
slubber turning the handle of the large wheel which
is connected by a strap with the drum. The cardings
are arranged upon a leathern or hempen apron, which
is mounted, in a slanting direction, at the end of the


Fig. 2377.
THE SLUBBING~BILLY.
frame, opposite to the moveable carriage. These
cardings pass under a wooden roller, called the billy-
roller, which presses lightly upon them, so as slightly
to compress them. In front of this roller is a move-
able rail, which, when it rests upon the cardings, pre-
WGOL.
1035
vents them from being drawn through, and, when
elevated, prevents the cardings from being drawn
forward by the retiring of the spindle-carriage.
When the spindle~carriage is wheeled close up to
the billy-roller, the clasp is opened by means of a
lever, so as to release all the cardings. The carriage
being then drawn a short distance from the clasp,
pulls forward a corresponding length of the cardings;
the clasp then falls down and holds the cardings
firmly, while the carriage, continuing to recede, draws
out and stretches that portion of the cardings which
is between the clasp and the spindles. During this
time the slubber keeps turning the wheel which
causes the spindles to revolve, thus giving the card-
ings the proper degree of twist. This twist does not
form yarn, for the slubbing has to be twisted in the
contrary direction, when it is afterwards spun at the
mule. Slubbings intended for warp yarn must be
more twisted than those for weft. The inclined
direction of the spindles gives to the cardings, or
rovings, as they may now be called, a twisting motion,
whereby they are continually slipping over the points
of the spindles without getting wound upon them.
When the rovings are properly twisted, the slubber
winds them upon the spindles, by pressing down a
faller-wire, so as to bear down the rovings from the
points of the spindles, and place them opposite their
iniddle part. He then makes the spindles revolve
while he slowly pushes in the carriage, so as to wind
the rovings upon the spindles in the form of conical
cops. The cardings are so tender, that, if allowed to
be dragged over the endless apron, they would be
‘liable to break. The rollers upon which the apron is
stretched are, therefore, made to revolve by means of
two unequal weights attached to them by cords.
When the carriage is pushed home, the heavier weight
gets wound up; and, when the carriage is drawn out,
this weight turns the roller and advances the endless
apron, so as to deliver the cardings at the same rate
as the carriage runs out. The cardings are brought
from the carding-engines by children, who lay them
over the left arm, and, by a slight lateral rolling
motion of the fingers of the right hand, not easy to
describe, join them on to the ends of the cardings on
the apron. This is repeated as often as necessary,
and, to prevent the improper thickening of the card-
ings at the juncture, each carding is smaller at the
ends. Some little tact is required by the children to
prevent any inequalities. They must be careful ‘not
to stretch the cardings in lifting them up, and must
join them evenly and effectually. Unless‘these points
are attended to, the slubbings form what are called
“ flies ” or “ratched car-dings.” Unless all the ends
are joined by the time the former cardings are drawn
through, the ends are said to be “ let up,” and when
this happens the work is considerably delayed. ‘
It is surprising to notice the rapidity with which
the piecening is performed; the fingers of the children
become polished in a singular way by the constant
handling of the oiled wool. “Children are preferable
as pieceners, not simply 'fronithe cheapness of their
labour, and the mobility of their muscles, but‘ from

their size, as they can work without constraint at the
billy-board, which must be kept low for the con-
venience of the slubber, and could not be properly
served by taller persons without painful and inju-
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Fag. 2378. MODERN snunnnm MACHINE.
rious steeping.” It is usually calculated that one
carding-engine will keep one billy with sixty spindles
in active employment. One slubber should have two
pieceners, so that each child has thirty cardings to
manage.
When the yarn required is large for coarse
purposes, the abb or shoot may be spun at once
at the billy—twenties are the smallest that are
thus spun. The slubbings are usually drawn to
half the size that the yarn is to be. When thus
spun, a thread of thirties, or 30 skeins to the pound,
would be slubbed to about fifteens, or 15 skeins to
the pound. The slubbings are then spun at the
mule, Fig. 2378, which does not difl’er materially from
the Cotton Mule. See Gorron, Fig. 664, and In
TRODUCTORY Essnr, p. cxlvi.
The Condenser, §»c.—-The operation of slubbing has
been lately superseded in many mills by a machine
called the Condenser. Where this machine is used,
the scribbling-engines are thus arranged: the thin
web or fleece is received upon a wooden cylinder,
round which it winds as it is taken oil’ the dofl'er by
the ‘comb. When it has wound round a certain num-
ber of times, a little mechanical contrivanee rings a
bell: this gives notice to the feeder to remove the
web on the cylinder, whichshe does ‘by running her
finger along the surface of the cylinder in a line
parallel to its axis. The web thus taken oii‘ is a
thick sheet of scribbled wool, its length being equal
to the circumference of the cylinder, and its breadth
to the length of the cylinder. This web is taken to
another engine and laid on the feedeloth, which it
just covers, and thus the feed of ‘the wool is regular
andynot dependent on the care of the feeder. This
second engine has the condenser attached to it. In
place of the‘ dofi'er there is a‘ large cylinder, not
covered‘with cards as the dofi'er would be, but having
rings of card round it, each ring being about a} inch
wide, and the distance between the rings about
one eighth of an inch. Now, it is evident that the
comb will remove not a continuous fleece, but a num-
ber of continuous strips of wool, each strip being
aZ— inch wide. These are to be formed into silubhings.
To efl’ect this they pass between rollers arranged in
1036
WOOL.
\Q/
the following way .--I‘wo wooden rollers are placed
parallel to each other, and in the same horizontal
plane, about 6 inches apart; over these is a continu-
ous belt of leather: between these and above them
is placed a third roller, covered with leather, which
rolls in contact with the leather belt. This upper
roller has also an end-0n motion; it travels constantly
about 2 inches forward and back again in the direc-
tion of its length. This is done by an eccentric at
one end. The strips of wool pass between these
rollers, and are .thus converted into slubbing ; the
action being precisely similar to that of the hands
when rolling a piece of wool between them, while the
revolution of the rollers carries the slubbing forward
as it is formed.
The arrangement of the rollers is shown in section
in Fig. 2379, having the end on motion. The slubbing
thus formed passes 011 to
a horizontal reel or bobbin
the whole length of the
width of the engine, and
round this the slubbing
Fic- 2379- from each ring of card is
wound. This when full is removed and placed on the
mules in a horizontal position, when the mule draws
out from it just as it would from the cops of slubbing.
Thus the slubber and piecing children are entirely
dispensed with, and the work is done much more re-
gularly.
Weaning, §e.-—The threads being now ready ‘for
weaving into cloth, require to be arranged for the
loom. The process of weaving has been fully de-
scribed under that head, [See WEAVING], but there
are a few particulars connected with the preparation
of the yarns for the loom which may be briefly noticed.
_In the operation of warping it is generally necessary
to wind the‘ threads into bobbins for the purpose.
When this is done, the yarn is first reeled, a number
of .naps being placed in a line in front of a. long reel,
which is turned by a handle, and the thread from each
_nap is wound round the reel, and forms askein. Each
skein is then placed on a smaller separate reel, and
the thread wound off upon a bobbin, either by hand
or more usually by, a simple machine, which winds a
large number at once. The operation of winding the
thread from the skeins on to. the bobbins is termed
spooling, the bobbin when full of thread being called
a spool.
In sizing the yarns, the whole chain is sometimes
operated on at once, but more usually the skeins are
_each sized, previous to warping, in a trough filled with
a solution of glue, in the proportion of about 1 lb. of
glue to 3 gallons of water. The skeins are soaked in
this trough, and as each one is taken out it is passed
between two rollers, covered with cloth, the upper
one of which is pressed upon the lower by weights.
In passing between these rollers, the excess of size is
squeezed out of the skein, and after hanging in a
heated- room for a short time, they are ready for spool-
ing. 'VVhen the whole chain is sized at once, a better
method is adopted for drying it: a cylindrical reel,
having at each end six arms projecting beyondxthe

reel, at right angles to its axis, is mounted on bear-
ings, and set in motion by wheelwork. The ends
of the chain are fastened to the reel, which as it
travels round on its axis winds up upon itself the
threads of the chain; the projecting arms, which are
of iron, are in the form of a sort of trough, the
open side of which is turned inwards; and as the
reel travels round, a long wooden rod is fitted into a
groove between two opposite pairs of arms; another
rod is similarly placed between the next two opposite
pairs of arms, and so on as each pair comes round,
the winding-up being performed slowly in order to
give the man time to arrange these bars in their places.
The object of this contrivance is, that as the chain is
wound up, each turn of threads may be kept separate
from the one before it, and the coils of the chain be
thus left open so as to allow the air to get between
and among the threads. The part of the room in which
this apparatus is placed is next shut close up, and
the reel or balloon, as the apparatus is called, is made
to revolve rapidly. Hot steam—pipes are laid on the
floor below the balloon, and the heat from these,
together with the rapidity of motion, effectually dry
the whole chain. In winding the chain on to the
balloon from the large balls of thread into which it is
formed by the warper, a separater or ravel is fixed in
front of the reel and parallel to it; this ravel, as
noticed under Wnavnve, is like a large comb, con-
sisting of a number of reeds or pieces of wood stuck
into a rail of wood; between these teeth the threads
of the chain- are passed, and this serves to keep them
separate, and of the right width of the intended cloth.
The chain is next beamed, or wound upon the beam
of the loom, from off the balloon, the threads being
again passed through a ravel to keep them apart. If
the chain is sized in skeins the weaver receives it in the
form of a large ball of threads, and he beams it on the
loom, using a ravel to keep apart the threads, while
an assistant turns the beam and winds up the chain. ‘
The number of threads in the chain or warp of a
cloth is calculated by tiers, a bier consisting of 40
ends or threads, and there being 5 biers or 200 threads
to the hundred.
In ordinary broad-cloth there are about 1,800, or
3,600 threads in the warp; these would be set in a
sley or read on the loom about 12 qrs. 3 nails wide,
2 ends or threads passing between every dent or reed
of'the sley. The width, when finished, will be 7 qrs.
A Venetian would have about 29 hundreds, 3 biers,
or 5,880 threads; would be set in sley 7 qrs. 3 nails,
with 4 ends in a reed; and would be, when finished,
6 qrs. 2 nails wide (or 56 inches).
A common fancy cloth, known under the general
- name of Heather, has 16 hundreds, or 3,200 threads,
is Sell in sley 7 qrs. 2 nails, and has a ends in a reed.
This will be 56 inches finished? -

( 1) Mr. Sheppard remarks :--“ I have given these three. as
specimens of various kinds of cloth, broad cloth being the re-
gular old-fashioned article known in the trade‘ as cloth. The
Venetian is a cloth which has a small neat twill‘ on the face: it
was our own make originally.‘ The other is from an article which
we are now making, and may be taken as ageneral specimen of
that class of goods.”
WOOL.
1037
In the production of stout cloths for winter wear,
a method was introduced in 1838, by Messrs. Daniell
8; Wilkins, of weaving a double cloth, so that while
one side is coarse and warm, the other side may be of
the highest finish. This cloth is soft, pliable, and
durable.
Bray/ing, Scom'z'ng, &c.——-The first operation the cloth
undergoes after it is woven is brag/ing, the object of
which is to get rid of the oil used preparatory to spin~
ning, and of the size used in dressing the warp. The
cloth as it leaves the loom is greasy and rough, and it
is subjected to a number of processes, which make it
compact in texture, and smooth and level in surface.
The first of these consists in working the cloth in the
stock. In this operation the scourz'rzy-sz‘oeks are used—-
a somewhat rude machine, which, under the name of
the falling-mill, is supposed to stand in point of an-
tiquity next to the corn or flour-mil]. The fulling-
mill consists of two or more ponderous mallets of oak,
working in a stools, as the frame of the mill is called.
The mallets are worked by z‘apz't-wheels, acting upon
their shanks, raising them to a certain height, and
then suddenly releasing them ; this allows their heavy
heads to fall by their own weight. The cloth is ex-
posed to their action in an inclined trough, the end
of which is curved, so that the cloth is turned round
and round by the action of the stocks, and every part
in turn exposed to the ‘blows. The trough contains
some liquid detergent substance. It is more usual,
however, to employ a machine called a was/rev‘, con-
sisting of two large heavy rollers, either of wood or
iron, the upper one resting on the lower; between
these rollers the cloth passes, and dips down to a
trough or bath of water or other liquid-beneath the
rollers. This form of washer is called a scouring-
mac/iz'ne in Yorkshire. The detergent substances
used in the stocks or in the washer are stale
urine and hog’s-dung: the action is continued for an
hour, then the cloth is run through another washer
with urine alone, and then with clean water until
the latter runs away clear: a little fullers’-earth is
also used in this process, and sometimes a small
quantity of soda. The cloth is then dried by being
hung up loosely in the stove—a large room heated by
steam-pipes—and after drying, it is buried. In this
process, a woman, called a burler, spreads the cloth
over a sloping board in front of her, and passes her
hand over the cloth to feel the knots which have been
made by the weaver; these she picks oli with a small
pair of iron tweezers made on purpose, and in this
way removes all knots and unevenness.
dialling or F2zZZz'ng..—-The cloth has now to be milled.
This is a very important process in the manufacture
of broad cloth, as by it the fibres of the wool are
felted together, and the whole surface of the cloth is
covered with a thick fulled face. The stocks or fulling-
mill consist, as above described, of an iron framework
supporting the ends of two or more heavy wooden
mallets, which are raised by projecting cams on a
wheel which revolves under the nose of the mallets:
the wheel raises the heads of the hammers to their
full height, and then, releasing them, allows them to

fall by their own weight on the cloth, which is con-
tained in a sort of iron trough beneath the mallets.
Soap is used in this process. The bars of soap are
first converted into shavings by a rough plane, and
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these are dissolved in hot water. The soap is dis-
tributed over the cloth by pouring it into a fold near
one of the ends; the man then takes up this fold,
and pulls out the cloth so as to form a sort of channel,
along which the solution of soap flows, until the cloth
has absorbed it all. The cloth is taken out two or
three times during the process of milling to prevent
its forming into wrinkles. .
An ordinary broad cloth will take from 60 to 65
hours to mill, and will require about 11 lbs. of soap;
it will shrink during the process from 12 quarters
wide to 7, and from 54¢ yards long to 40. A Vfillfi':
tian will require about 12 hours, take from 6 to 7 lbs.
of soap, and shrink in Width from '7 quarters 3 nails
to 6 quarters 2 nails, and in length from 54: yards to
4:5 yards. A Fancy Heather will require 10 hours,
take 10 lbs. of soap, and shrink in width from 7 quarters
2 nails to 6.quarters 2 nails, and in length from 54 to
49 yards. After the fulling, the cloth is passed
through a washer with clean water, to remove the
soap.
A great improvement has of late years been intro-
duced to supersede the old falling-stocks: a machine
called the Falling-machine is now coming into general
use; it is more convenient, does the work in a shorter
time, and requires less soap. It consists of a strong iron
framework, AA, fig. 2382, supporting a wooden case,
B 13, which is screwed on to it; c o, are strong cog-
wheels, the lower one of which is set in motion by the
drum K, fig. 2381. On the axis of these wheels are fixed
two narrow wooden rollers, which are shown in section
in fig. 2383; the lower one, D, has a copper flange on
each side, the use of which will be noticed presently.
On a horizontal line, passing between these rollers,
there is fixed a sort of trough or shoot, r, a part of the
top of which is moveable on a hinge, as shown in
Fig. 2383 : at the end of this movable lid there is a
kind of box, 11, in which weights are placed. -The.
upper roller E is pressed on the lower one by the
springs s, the force with which they press downwards‘
being regulated by the nuts at the ends of the rods
attached to the springs. The cloth is shown in fig. 2381,
in the position which it occupies while being milled ;
1038
VVQOL.
the two endsof the cloth are fastened together so as
to form an endless cloth. Passing through two holes
in the piece of wood 0, the two parts of the cloth
pass together over and between guide-rollers till the
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the way represented, the weights in the box 11
preventing it from passing freely out of the trough.
The force thus exerted between the rollers and in‘ the
trough has the effect of milling the cloth and causing
the fibres to felt together, just as in the stocks. Soap
is' added by being poured 'on the cloth in front of the
machine'as it is at work, the doors 1) D being made to
op‘cir- for that'purpo'se.‘ ~_ '
' Teazli'rzy.-‘—-After being'dried, the cloth has to be
dressed {this is done at the gig-mill. It is first r‘ozzgfied
or rowed, by being teazled both ways, so as to raise
the/wool for about 20 hours. The operation of teazl-


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Fig. 2384.

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united cloths pass between the rollers E D, being
kept in place by the copper flange before mentioned.
The action of these rollers forces the cloth on into
the trough F, where it is doubled and folded up in
























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Fig. 2383
teazles are used on a piece of cloth 440 yards long;
each head consists of a large ‘number of flowers, sepa—
rated from each other by long scales, at the end of
which is a fine book, which forms the eflicient part
of the teazle. These natural hooks are sufliciently
strong to overcome slight impediments, but if they
become fixed in a knot which they cannot disentagle,
they break. It is this property, so diflieult to imitate,
which has hitherto prevented the introduction of
wire brushes or metallic teazle-cards ; ‘for their points
or hooks, instead of yielding, tear out the fibres, and
injure the surface of the cloth.
Cloth was formerly teazled by hand, a number of
teazle-heads being fixed in a small wooden frame with
cross handles 8 or 10 inches long, with which the
surface of the cloth was worked, first in the direction
of the warp, and then in that of the weft, the cloth
being damped for the purpose; when the teazle-heads
had become choked up with wool, they were cleared
' out by children with small steel combs, and when the
teazle-points had become soft by moisture, the heads
were set aside to dry.
Teazling is now performed by- machinery. In the
Gig-mill, Fig. 2385, the teazles are arranged inlong

ing is performed by means of the prickly flower-heads
of the Teazle, Fig. 2384, a species of thistle (Dip-
sacus fullonum), which is cultivated in the clothing.
counties,‘ vfor the purpose.1- From 2,000 to 3,000
frames’ attached to a hollow drum or cylinder, and the
(1), The teaz‘le is a biennial plant, and is_ sewn in drills: it is
thinned out by the hoe, and kept clear from weeds during the first
year, and‘ also weeded during the second year. The ripe heads
are‘ cut. and- dried for sale‘- The -crop is‘ an ‘uncertain. one, and.
liable to‘be spoilt by a continuance of: wetweather. In Yorkshire,
’ the average price of a pack of teazles, containing 13,500 heads,
in‘the’ proportion ‘of 6 large 'to :4 small heads, isifrom' 52'; to 7A,!’
and in times of scarcity as much'as 22L . » ‘
WOOL.
1039
cloth, guided by a number of rollers, is moved in
a direction contrary to that of the cylinder, by the
rapid revolution of which, and the slower motion of
the cloth in a contrary direction, the loose fibres of
the wool. are brought to the surface. When the
teazles become clogged with wool, they are removed
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Fig. 2385.
GIG—MILL-
from the cylinder and cleaned. In the gig-mill in
use in Messrs. Sheppard’s mill, the cloth is wound on
a roller beneath the large cylinder carrying the teazles,
and from this passes over the teazles, and is then
wound up on another roller above. Two boys attend to
one gig to pull out the cloth, and reverse the motion
when it has been rowed once, so as to re-wind it on
the lower roller.
Skeanz'ng.--The filaments drawn out by teazling are
of unequal length, and require to be shorn to make
them level. The shearing of cloth is an important
operation, and is varied according to the quality of
the material and the appearance required. It was
formerly done by hand with a pair of shears, and the
introduction of machinery for the purpose at the
beginning of the present century led to serious riots
in the West of England. One arrangement for me-
chanical shearing consists of a fixed semicircular
rack, within or behind which is a cutting edge called
a ledger—blade, and a large revolving wheel containing
8 small cutting—disks, which, in contact with the
ledger-blade, form a number of delicate cutting-shears;
each cutting-disk is furnished with a tooth-pinion
working into the semicircular rack, so that as the
large wheel revolves the cutting-disks acquire an
- independent rota-
tory motion, in
addition to their
revolution with
the large wheel.
In Fig. 2386, the
cloth is repre-
sented by the
shaded parts, and
the machine may
be made to travel
over the cloth, or
the cloth may be
moved beneath


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Fig. ass-s.

the stationary machine. The machine, however, which
is chiefly used for the purpose, is Lewis’s Cutting-
nzac/zz'ne: it consists of an iron cylinder (the length
of which is equal to the width of the cloth) with‘
on tting-blades passing spirally round it, and a straight
steel blade is fixed in contact with these cutter-
blades and parallel to‘ the cylinder. Anything placed
between this blade and the cutter-blades will, when
the cylinder is turned round, be out as if with a
pair of scissors; the whole apparatus is movable
on a hinge. The cloth passes over another steel‘
blade directly below the cutter, and thus the wool is
exposed to the action of the latter, which, rapidly
revolving, shears it off. The depth to which the cutter
is allowed to fall on the cloth is regulated by small
pieces of paper put under‘ a projecting stud, and the
falling out of one of these papers is sufiicient to
damage the piece of cloth. The whole cutter is sup-
ported on a frame, and travels over the cloth across
its width; as soon as it has been over once it is
drawn back, the cloth is shifted on, and the cutter
again travels over it. Two boys generally attend to
two cutters, and one man has the superintendence of
the shop, and attends to the papers, and regulates
the depth to be taken olf at each kerf or cut. This
is a delicate operation, as the cloth requires to be out-
many times. If too much were taken off at once, the
surface of the cloth would be injured. .-
The Broad Perpetual, Fig. 2387, is used for cutting
the backs of some goods, or the~face of some dry-



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CLOTH-SHEARING MAC H IN E.
Fig. 238?.
dressed articles, such as the heather-s mentioned
before. It is in extensive use in Yorkshire, but it
does not answer well for Mac/cs or fine clot/is.
In' shearing fine cloth it is cut, 182‘ way, 5 or 6'
kerfs being taken off, a kerf being the wool taken off
at one passing through the cutter. It then goes
back to the gig-mill, and is marred’ or teazled one way
for 3 hours or so, then dried and re-cut, 2d way,
6 kerf or more being taken off.
Pressing—The next of the finishing processes is
to arrange the cloth in regular folds, and submit it to
the action of a hydrostatic press. A polished pressing-
board is placed between each fold, to prevent the sur-
faces of the cloth from coming in contact; and the
1040
WOOL.
pieces of cloth, where many are pressed at the same
time, are separated by an iron-plate between every
two pieces. For hot-pressing, 3 hot iron-plates
_ are inserted between the folds at intervals of about
20 yards, and the heat of the plates is moderated
by thin sheets of cold iron placed above and below
the hot plates. The pieces of cloth are piled up in
the press, and subjected to an intense pressure, which
is maintained until the plates become cold. The cloth
is then taken out, and folded again in such a way
that ‘the creases of former folds may come opposite
the flat faces of the pressing-boards and be removed
at the second pressure. Hot-pressing gives a satiny
lustre and smoothness to the face of the cloth; but
as this is apt to become spotted by rain, another pro-
cess has been introduced, namely, Boiling. The cloth
is tightly wound upon a wooden or iron roller, and
immersed in water, heated to 170° or 180°, for 5
hours; it is then taken out and allowed to cool for
Q4! hours. It is treated in this way four or five times
in succession, and then washed with fuller’s-earth.
After this it is racked or stretched tightly'on an iron
frame, called the rack or teeter, in a stove, or room
heated by steam pipes.
In place of the roller-boiling another process is now
often adopted, called Steaming. After the cloth is hot—
pressed, it is rolled round a hollow copper roller, per-
forated with a number of holes, a piece of cloth being
wrapped round the roller first, to protect the cloth
from being coloured by the copper: steam is then
admitted into the roller, and allowed to pass through
all the folds of. cloth. If high-pressure steam is used,
this will be effected in 5 or 10 minutes; but if the
pressure is low, it will require 1%, hours : after this it
is boiled twice. This steaming process saves the time
of 3 boilings, and _gives a nice satiny finish to the
goods.
Several of the processes which we have thus de-
scribed separately, are frequently alternated with each
other. The cloth is passed several times through a
Brushing-machine, consisting of a series of brushes
attached to a cylinder. In passing through this
machine the face of the cloth is softened by being
slightly damped by exposure to steam, which escapes
in minute jets from a copper box, extending the whole
length of the brushing-machine.
In finishing the cloth previous to cold-pressing, it
is carefully examined before a strong light, and pic/seal,
fine-drawn, and marked. Picking is similar to burling,
its object being to remove blemishes from the surface,
and to cover any spots which may have escaped the
action of .the dye, by touching them with a pen dipped
in. dye-stuff. The object of fine-drawing is to close
any minute hole or break in the fabric, which is done
by introducing, by means of a needle, sound yarns in
the place of the defective ones. Marking consists in
working in with white or yellow silk a word or mark,
indicating the quality and number of the piece. The
cloth is lastly made up for the market, in pieces or
tales, and into emis or half-pieces. .
It is stated in the Jury Report, Class XII, that
“ The continental methods of producing a permanent

face are totally different, much shorter in their pro—
cesses than ours, and performed at a much cheaper
rate. Their methods are—the one by rolling the
cloth tightly round a hollow perforated cylinder, into
which the steam is introduced to produce the desired
effect; the other, and more general one, by folding
the cloth and putting it under very powerful pressure,
then allowing the steam to penetrate the whole bulk.
Both these methods cause a hardness, which is ob-
servable in all continental productions, and would be
more so if applied to stouter fabrics. There are also
to be seen on cloths, that have been so treated, marks
of the folds, which cannot be efi'aced by any ordinary
means. Several houses in Leeds have tried this plan,
but found that the fold-mark and hardness of the
fabrics formed obstacles to their sale in the home-
market, though not for exportation; consequently it
has been adopted to meet the competition abroad.
“ Considerable attention has been given to the dye-
ing of cloth in the different countries, especially the
finer fabrics, which are all equally well and permanently
dyed. In. the middle qualities, some are permanently
dyed, and others not; this is the case in all countries,
and in the lower qualities (with some few exceptions)
they are all of a common dye. This is a circum-
stance easily accounted for by the cost of the perma-
nent dye being considerably more, and from its
detracting slightly from the appearance and feel
of the cloth,--facts which, it must be admitted, are
great impediments in these competitive times, al-
though there can be no doubt that real and ultimate
economy must remain with a permanently dyed
article.” ‘
Snc'rron II.—-On THE Manurncrunn or Wons'rnn
YARN.
The preparation of worsted yarn resembles that of
cotton, and is essentially different from that of short
20002 or clot/ring yam; for while, in the latter, the
fibres are entangled and crossed in every direction, in
order to assist the felting property, care is taken in
the preparation of the former to dispose all the fibres
as nearly as possible in parallel lines.
The first operation in the preparation of long wool
is mas/ring in soap and water. Much of the moisture
is pressed out by rollers, after which the wool is con_
veyed in large baskets to the drying~room, where it is
spread over the floor. The drying-room is usually
situated immediately over the ‘boiler of the steam-
engine, and is thus economically heated. When the
wool is dry,‘ it is removed to a kind of willowing
machine, called the 171%0176’1". This is attended by a
boy, whose business it is to spread the wool, with
tolerable regularity, over a feeding-apron, which, by
advancing, delivers the tufts of wool to a pair of
fluted rollers, which convey it to a fanning apparatus.
After the wool has passed through this machine, it
is ready for combing. For the finer descriptions of
long wool, this is still done by hand. It is a laborious
and unhealthy occupation, being carried on in hot
rooms. The wool-comber employs three implements,
namely, a pair of combs, one of which is represented
WOOL.
1041
in Fig. 2388, a past, Fig. 2389, to which one of the
combs can be fixed, and, a small stove, Fig. 2390,
called a comb-pot, for heating the teeth of the combs.
The wool-comb is com-
posed of two or three rows
of pointed, tapering steel
teeth, the rows being‘ of
different lengths. They are
fixed to a wooden stock or
head, which is covered with
horn, and from this head
proceeds a perforated han-
dle, made to fit into certain
projections in the post, upon
which the combs are occa-
sionally rested during the
operation. The turned—up
part of the iron stem enters
a hole in the handle of the
comb, while the staple near
the post enters the hollow
end of the handle, thus
holding the comb securely.
The comb-pot consists of
a flat iron plate, heated by
fire or steam; and above this
is a similar plate, with suf-
ficient space between the
two to admit the teeth of
. the comb.


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Fig. 2390.
The heated comb being fastened to the post with
the teeth upwards, the workman takes a handful of
wool, sprinkles it over with oil, rolls it up in his hands
to distribute the oil uniformly, and then throws about
one-half of the wool over the points of the comb,
drawing it through them repeatedly, leaving each
time a few straight filaments in the comb. When
the handful of oiled wool is thus disposed on the
comb, the comb is removed to the stove, so as to
expose the wool to the influence of the heat. An
empty comb is at the same time taken from the stove
and mounted on the post, where it is filled with wool
as before. The man then takes the two combs, and,
sitting down upon a low stool, holds one of them with
his left hand over his knee, and, holding the other in
his right hand, introduces the teeth of one comb into
the wool stuck in the other, and draws them through
it; by which operation the wool is transferred to one
VOL. II.

comb. This process is continually repeated, until the
fibres age laid truly parallel. The man begins by
combing out the ends of the wool, advancing gradu-
ally from one end to the other, until at length the
teeth of the combs are very near together. About
one-eighth of the wool remains on the teeth of the
comb after each operation; and this quantity, which
is called noyl, being too short for the comber to grasp
in his hand, is transferred to the short-wool manu-
facturer. The wool, after it has left the comb, re-
quires to be combed again, at a lower temperature,
before it is fit for the spinner.
Many attempts have been made to supersede this
operation by self-acting machines. One of these
consists of 2 large wheels, 10 feet in diameter,
set nearly upright, the comb-teeth forming a circle
round the rim of each wheel, at right angles to its
plans, the points of the comb in the 2 wheels being
turned towards eaqlr other. The wheels are furnished
with hollow iron spokes. filled with steam, for the
purpose of maintaining a proper combing heat. A
boy, seated on the ground, strikes the wool in hand-
fuls upon one wheel, which is made to revolve slowly
for the purpose. The wheel is then made to revolve
more rapidly, and the teeth of one wheel, sweeping
obliquely over the teeth of the other, smooth out the
tangled looks with great delicacy and. precision.
“When the wheels are set in rapid motion, the loose
ends of the fleece, by the centrifugal force, are thrown
out in the direction of radii, upon the teeth of the
other revolving comb-wheel, so as to be drawn out
and made truly straight. The operation commences
upon the tips of the tresses, where the wheels, by the
oblique posture of their shafts, are at the greatest
distance apart; but as the planes slowly approach
to parallelism, the teeth enter more deeply into the
wool, till they progressively comb the whole length of
its fibres. The machines being then thrown out of
gear, the teeth are stripped of the tresses by the hand
of the attendant; the noyls, or short refuse wool,
being also removed, and kept by itself.”
Breaking, Drawing, and Spz'mzz'ng.-—-The wool, as it is
combed into slivers, is formed into’ narrow bundles,
called traps, each containing about a pound and a half
or two pounds. These being unrolled, the slivers are
separated and thrown loosely over a pin, within reach
of the attendant, who takes a? sliver, spreads it flat
upon an endless felt or feeding-board, presenting the
end to the first pair of rollers of the sliver-50x or
breakingjframe, which draw the sliver in. When it
has passed half through, the end of another sliver is
placed upon the middle of the first, and they are
drawn through together. Care is taken to splice the
long end of one sliver to the short end of another.
When this second sliver has p sed half way through,
the end of a third is placed on t .middle of it; and in
this way the short slivers are united and’ extended by
other pairs of rollers into one long and uniform sliver,
8 times the length which it had on the feeding-
board. The slivers from this machine are received
into cans, the contents of 8 of which are drawn into
one at the drawing-frame. These are also received
3x
1042
WOOL.
into cans, and 'being again drawn out and slightly
twisted, are wound upon bobbins. At about the fifth
drawing, a number of yards are weighed, so as to
ensure a given length to a given weight of yarn. If
the sliver is not of the length required for the size of
the worsted intended. to ‘be spun, the speed of the
drawing-frames is changed accordingly. The roving
and spinning so closely resemble those processes in
the cotton manufacture as to require no 'further de-
scription in this place.
Sncrron IIL—Strarrsrrcs.
The woollen and worsted manufactures have under-
gone several changes, consequent on the introduction
of improved machinery and steam-power. The seats
of the manufacture were originally determined by
the facilities for procuring the raw material, and the
presence of water-power. Improved systems of con-
veyance have also had an effect in shifting the
‘localities of the manufacture. Previous to the reign
of George 111., when the roads of Great Britain were
little better than bridle-paths, wool was conveyed on
horses, and so general was this employment that the
term pack-[tomes had its origin in the packs of wool
which they carried. Under such a slow and expen-
sive system of conveyance the manufacturer would be
induced ,to settle in districts where the wool was
grown, and where a market existed for the disposal
of his manufactured products. The quality of the
wool produced in the neighbourhood would also
greatly determine that of the cloth. Such circum-
stances as the above led to the establishment of
a large number of small manufacturers in different
parts of the country, each master giving employment
,to his poorer neighbours and their families, who had
their spinning-wheels and looms in their cottages, and
a number of children and servants worked under the
direction of the master himself. But when turnpike
roads were adopted, and canals came into use, the
woollen manufacturers gradually established them-
selves in South Lancashire and the West Riding
‘of Yorkshire, where, by means of canals, a cheap and
easy means of communication was opened to Liver-
pool and to Hull; which sea-ports now began to re-
ceive wool from various parts of the kingdom, and in-
.deed of the world, thus opening markets both domestic
and foreign for the disposal of the manufactured goods.
The natural capabilities of Lancashire and Yorkshire—-
such as its water-falls, its coal, iron, and limestone
-—furnished great facilities for the construction of
machinery; accordingly in these counties the manu-
facture of coarse woollen goods continued for many
years to flourish. Gloucestershire, Wiltshire, and
Somersetshire producing the finest English wools, long
maintained their reputation for fine cloth; and those
counties, moreover, had the advantage of Bristol as
a sea—port, which supplied them with the fine wools
of Spain and Portugal. The finest cloths of the
West of England were sent to the Blackwell-hall
factors in London, for sale and distribution. The
introduction of the merino sheep into the north of
Europe, as noticed in an early part of this article.

led to the production of wools superior even to those
of Spain—a circumstance which, coupled with the
increasing facilities of communication, enabled the
Yorkshire manufacturers to obtain supplies of fine
wool, and thus to rival the West of England in the
production of fine cloth. ‘
The Yorkshire clothing district extends from north
to south about 410 miles; its mean breadth is about
20 miles; so that it occupies an area of about 800
square miles: it includes the large manufacturing
towns of Leeds, Huddersfield, Bradford, Halifax, and
Wakefield. Leeds is now regarded as {the first town
in England ,for the extent and variety of its manu-
factures in wool; its chief trade is in the middle and
lower qualities. This town and the surrounding dis-
trict contributed to the Great Exhibition an extensive
assortment of woollen cloths in fine, middle, and low
qualities, eloakings, beavers, mohairs, doeskins, casse-
miere, cashmerettes, tweeds, and pilots, which, for ap-
pearance and cheapness, according to the verdict of the
Jury Report, Olass XII, maintained the high position
for which it has so long been in repute. The manu-
faeturers of Leeds largely supply the foreign markets,
and vary their productions according to the taste and
requirements of each. Huddersfield and its neigh-
bou-rhood rank next to Leeds in importance, and
supply a great quantity and variety of goods. “ Here
an immense portion of the fancy trowsermgs are
made, beside, broad—cloths; but the productions of
Huddersfield are principally for home consumption,
and of the middle and lower qualities. This town,
in 1820, made goods from home-grown wool only,
but since that period it has risen into great im-
portance.” In the Exhibition a number of double-
faced cloths from this seat of manufacture attracted
much notice. They presented a different colour on
each side, an idea prohaply suggested by Daniell’s
double cloth already referre‘d to.“ At present these
coloured cloths must‘ be cogsidgred rather as curiosities
than as a legitimatg branch pf mapufacture. Most of
the clot/1. produced in this diptrigt is from the neighbour-
hood of Leeds, Wakefield, Huddersfield, and Saddle-
worth; Leeds being the great mart for coloured or
mixed cloths, as they are called, which are wholly made
of dyed wool, and w/lz'lc broad cloths. Flanacls and
baz'zes are manufactured in and near Halifax, and also
cloth used for the army. The blanket and fiasfiz'ag
trade is carried on in the district between Leeds and
Huddersfield. Worsted-spinning is extensively carried
on at Bradford, and slafifs' are made in its vicinity,
and also at Halifax and Leeds. Narrow dolls are
made in and near Huddersfield. Broad cloths’ and
kerseymeres are made at Saddleworth. Wakefield
was long celebrated for the skill of its cloth dyer-s.
Dewsbury is the chief seat of what is called the
slorlc@ trade. Old woollen ,cloth, &c., which was
formerly used as manure, and cast off woollen clothmg
of every kind, now form the staple of this trade}
The materials are subjected to ‘certain preparatory
processes, after which they are‘torn' to pieces by mas
chinery, and reduced to the original condition of wciol,
which is spun again, sometimesi withnn admixture
wooL. \
1043
of fresh wool, and is again woven into cloth. Shoddy
cloth answers very well for the purposes of padding,
&c., and was long confined to such uses; but the
improvements effected in its manufacture, and espe-
cially in the art of dyeing it, have led to its applica-
tion to blankets, flushings, druggets, carpets, table-
covers, cloth for pilot and petersham great-coats, &c.
It is even used largely in making the clothes of the
army and navy; and most persons, at some time or
other, wear clothes (especially if they are cheap)
made of shoddy cloth. Woollen table-covers are
commonly made of shoddy, the pattern being printed
by means of aquafortis. Bochdale, in Lancashire,
manufactures flannels, baizes, kerseys, and broad-
cloths.
In the West of England, Gloucestershire still
maintains its trade, Stroud and its neighbourhood
being the chief seat of the manufacture. Stroud,
or Stroudwater, is so called on account of the purity
of its waters, which have been celebrated for centuries
for dyeing scarlets and other light colours. Fine
broad cloths are manufactured in this neighbourhood,
and also at Ebley, Eastington, Stonehouse, and Min-
chinhampton. Trowbridge, in Wiltshire, is the next
town and neighbourhood of importance in the West:
it manufactures largely and well. Bradford, Wilts,
is less noted than formerly. Chippenham, in Wilt-
shire, makes some first-rate superfine broads; and
Melksham, in the same county, is also in some repute.
Frome, in Somersetshire, is not so much celebrated as
formerly for superfine bonds, but it has a high cha-
racter for fancy sin-quarters. At the Great Exhibition
were some beautiful specimens of cloths, beaver, and
Venetians, from Frome, and from Twerton, near
Bath. Scotland makes some excellent goods‘ of a
cheap description for trouserings.
Halls, for the sale of cloth, are established at
Leeds, Halifax, Huddersfield, Bradford, and other
places. The following notice of the Coloured-cloth
Hall at Leeds, was prepared from personal inspection
by the Editor for his work on “ The Useful Arts and
Manufactures of Great Britain,” and will probably
be a sufficient description of the management of
these buildings. There are two cloth-halls at Leeds:
the Coloured-cloth Hall, built in 17 5 8, and the White-
cloth Hall, built in 177 5. The cloth-market was
formerly held in an open street. The Coloured-cloth
Hall is a plain building, occupying three sides of
a large square, divided into 8 compartments, which
are called streets: these are, King—street, Queen-
street, ’Change-alley, Mary’s-lane, Prince of Wales’s-
street, Cheapside, Commercial-street, Union-street,
and New-street. Each street contains two rows of
~stands facing each other: each stand projects from
the wall 11 or 12 feet; but it measures only 22
inches in front: it is inscribed with the name of
“the clothier to whom it belongs. No one can occupy
‘a stand unless he has served a regular apprenticeship
to the clothing business. Each stand, which is the
'absolute freehold property of the holder, cost origi-
iially about 3!. ; and the value has been'as much as
:eight or ten times that amount; but, since the ex-

tension of the factory system, a good deal of cloth
produced in the woollen district is sold without pass-
ing through the halls, which have, consequently, lost
much of their importance, and the stands do not 'now
exceed their original valiie. The markets for the
sale of coloured cloths are held on Tuesdays and
Saturdays, on which days only are the merchants
permitted to make their purchases in the halls. The
time of sale commences, by the ringing of a bell, at
nine o’clock in summer, and half-an-hour later in
the winter half of the year from October to March.
At the end of an hour the bell is rung again, to warn
the buyers and sellers that the market is about to
close; and in another twenty minutes the bell is rung
for the third time; after which, a fine of 5s. is im-
posed on every buyer. The White-cloth Hall, situ-
ated in another part of the city, is opened immediately
afterwards, and is subject to similar regulations. The
cloth is brought to the halls in the undressed state;
the purchasers, who are the proprietors of what are
called finishing-shops, conduct the various finishing
processes described in SECTION II. The goods pro—
duced in the West of England, and in Norfolk, are
not sold in cloth-halls, but at public fairs or markets,
or to the agents sent round by the drapers.
In this notice of the woollen and worsted manu-
facture, it might be expected that some details should
be given of the modes of manufacture of the various
descriptions of goods in which wool is employed; but
it may be stated that such goods as blankets, flan-
nels, baize, stuffs, merinos, mousseline-de-laines or
wool muslins, bombazets, tammies, shalloons, says,
moreens, calimancoes, camlets, lustrings, and a num-
ber of othershare produced by some of the means
already described under WEAVING. Many divisions
and subdivisions of the manufacture differ more in
their results than in the means by which those results
are attained. The mixture of woollen with worsted
yarns, or either of them with cotton or silk, together
with various methods of dyeing and fancy weaving,
leads to an almost endless variety of woven fabrics.
Thus, to give a few examples Z—loer'seymere is a filled
twilled fabric; serges are also twilled, but the warp is
worsted and the weft woollen; blankets, and many va-
rieties of plain coarse cloth, are made of very soft yarn,
afterwards worked up into a kind of pile by milling;
bonzoazeen is a mixture of worsted and silk, twilled;
poplin is a similar mixture produced by plain weaving;
stnfis entirely worsted; merino is a fine woollen twill;
snnonz'es and orleans are made of woollen mixed with
cotton yarn: cashmere ought properly to be made of
the wool of the Cashmere goat; but most of the fabrics‘
named ccsfimeres are made of sheep’s wool; okaZZz's is
produced from a silk warp and a woollen weft, and is
usually printed; monsselz'ne-daldine was, as its name
implies, originally all wool; but it is now commonly
mixed with cotton, and printed; Norwich-amps is
composed of wool and silk; (hojie—ele-Ljon, of worsted
and silk. The fabrics called waistooatz'ngs are exceed-
ingly numerous. . -
The condition of the worsted trade at the time of
the Great Exhibition may be estimated by the follow-
3x2
10M
WOOL—WOOTZ—YTTRIUM—ZINC.
‘ing statement from the Jury Report, Class XII. :—
“ The classification of worsted stuffs contained in the
list drawn up for the Jurors has reference to the ma-
terials of which they are composed; viz.—
1. Fabrics composed entirely of wool.
2. Ditto of wool and cotton.
3 Ditto of wool and silk.
4. Ditto of wool, silk, and cotton.
5 Ditto of alpaca and mohair mixed
with cotton or silk.
“ The first of these divisions comprises the well-
known fabrics called ‘ merinos’ double-twilled, so deno-
minated from the Spanish wool of which they were first
manufactured. In this article the French have always
had an unquestionable superiority, and many of the
specimens in the Exhibition fully maintain their repu—
tation. There are some goods of this class, however,
inthe Bradford department, but little inferior to them.
In single-twilled merinos the worsted manufacturers
of Yorkshire have at all times had the decided preemi-
nence. Shalloons, says, serges, lastings—all stout and
heavy articles—are manufactured chiefly at Halifax
and at Keighley. Damasks for curtains and hangings
are also made at Halifax, and this branch of the trade
has arrived at great perfection, both in excellence of
material and elegance of design. Of the fabrics com-
posed of wool and cotton, the articles denominated
Cobourg and Orleans cloth—the former being twilled
and the latter plain—have been staple manufactures,
of which the, consumption has been immense; they
are made chiefly at Bradford and Keighley. Many of
the silk warp and worsted weft fabrics are distin-
guished by their richness and durability. The alpaca
and mohair manufacturers (carried on at Bradford and
Bingley) are remarkable for their softness and bril-
liancy, and the great variety of purposes to which
they are applicable. The importation of alpaca wool
has increased from 7,000 bales in 1836 to 20,000
bales in 1850, and of mohair, from 5,621 bales in 18411,
to 12,8,81l bales in 1850. It is in the production of
articles in which wool of various kinds is combined with
cotton and silk, that the superiority of the British ma.-
nufacturer is most apparent, no such goods being pro-
duced on the Continent in any extent, or of ‘any great
excellence. This result could not have been attained,
had not the skill and enterprise of the manufacturer
been aided by that of the worsted dyer. The chemical
processes required in order that a fabric composed of
both vegetable and animal substances may be made
to receive an equal and regular dye are necessarily
varied and intricate; but so successful have been the
efforts of the dyers, that goods made of white cotton
warp and worsted weft can be ‘dyed quite as perfect
rm colour as French merinos composed of wool alone.
“ The consumption of these various manufactures
is immense. The looms are capable of producing up-
wards of 80,000 pieces per week, averaging 30 yards
each. These goods are not only sold in the United
Kingdom, but are largely exported (as the following
returns will show) to the United States of America,
and _to Germany, and other parts of the Continent of
Europe.

“ Exports, during the six months from the 1st of
January to 28th June, 1851 :—
Woollen and worsted yarns 5,567,854 lbs.
Woollens and cottons, mixed (va1ue)......... 2330,4781.
Stufi's, woollen and worsted ditto ....... .. 1,896,22Sl.
“ All that is now wanting in the English worsted
' trade is, that the same enterprise should be exhibited
as heretofore in the working up of materials into new
forms, combined with greater taste in the production
of fancy goods.”
Some further statistics respecting wool will be
found under WEAVING, SECTION VIII.
WOOTZ, or INDIAN STEEL. When highly car-
buretted steel is fused with alumina, a white, granular,
brittle alloy is formed, containing 6'4, per cent. of
alumina. On fusing 67 parts of this alloy with 500
of steel, a compound similar to Bombay Wootz is
obtained. Polished surfaces of this material, when
washed over with dilute sulphuric acid, show the
damask of the celebrated sabres of Damascus, which
renders it probable that they were formed of this
substance. The process of Damasceening is described
under GUN. See also Inrnonuc'ronr Essnr, page
cxv.
WORSTED. See WooL.
WORT. See BEER.
WOULFE’S APPARATUS. See DISTILLATION,
Fig. 717.
XANTHINE. See MADDIER.
YARD. See WEIGHTS AND MEASURES.
YARN. See CorroN—FLAx—WooL—WEAvINe.
YEAST. See BEER.
YEW. See WOOD.
YTTRIUM (Y 32). The metal of a very rare
earth discovered by Professor Gadolin, in 179d, in a
mineral from the quarry of Ytterby in Sweden. The
mineral, which has been called Gadolz'rzz'z‘e, is composed
of yttria, silica, and the oxides of iron and cerium.
Several processes have been described for obtaining
yttria (YO); but it is probable that the substance
described as pure yttria is a mixture of that oxide
with two'others, the bases of which have been
termed erbium and terbz'um, both derived from the
word ytterby. These three rare metals have received
no application in the arts.
ZAFFRE. See COBALT.
ZERO. See THEnMoMErEn.
ZINC. (ZN 32.) The ores of zinc were made use
of from the earliest times for combining with copper
in the manufacture of brass. Zinc is first mentioned
as a distinct metal by Paracelsus, but it appears to
have been known in China and in India from an early
period, articles for use and ornament having been
made of the metal. The ores of zinc chiefly used in
commerce are the carbonates and silicates, and some-
times the-oxide, and the native sulphuret or Meade.
The ores occur in veins traversing primitive or tran—
sition rocks, or in floors and stockworks in more
recent formations. Rea? oxide of zinc is sometimes
metwvith in the crystalline form, as at Sparta, in New
Jersey. Its specific gravity varies from 54 to_5'5;
its lustre is adamantine, and when scratched it gives
ZINC.
10415
an orange-yellow streak. Its colour is red of various
hues, in some cases inclining to yellow; it has two
distinct cleavages at an angle of 120°; it is brittle,
and its fracture is conchoidal. There was a splendid
specimen of this mineral in the Great Exhibition, as
noticed in the Intrnonuc'ronr Essar, page xcvii.
The sulphuret of zinc, or blende, occurs massive, or
in dodecahedrons, octohedrons, and other allied forms.
When scratched it yields a streak varying from white
to reddish brown; its colour varies from resin yellow
to dark brown or black, and some specimens have a
green or red tint; it has a waxy or resinous lustre,
and its recent fracture exhibits a brilliant surface.
Its specific gravity varies from d'O to 4:1. It some-
times becomes electric by friction. The dark speci-
mens frequently contain sulphuret of iron, and the
red specimens a small proportion of sulphuret of
cadmium. The dark colour of the former obtains for
it the name of black jack among our English miners.
Blende occurs in rocks of all ages, and is usually
associated with the ores of lead, and sometimes with
those of copper, tin, and silver. This ore is difficult
to smelt, and is therefore not much used as a source
of the metal. Cardcnale of zinc, or calamz'ne, occurs in
masses of crystals, and in pseudo-morphic forms; its
colour is yellowish-white, but if it contain iron, brown
or reddish-brown. It has a vitreous, somewhat
pearly lustre, white streak, and a cleavage parallel to
the faces of the rhombohedron, which is its primitive
form. Its specific gravity varies from 4:3 to M5.
It is one of the most important of the ores of zinc.
The silicate Qf zinc or electric calamine occursjn
stalactic, mamellated, massive, and other forms, and
also crystallized. Its colour is commonly white, but
specimens of a blue, green, yellow, and brown colours,
are sometimes met with. It has a vitreous lustre
and a white streak. Its specific gravity varies from
3'3 to 3'6; its fracture is uneven; its crystals some-
times become electric by heat or by friction; it is a
valuable ore, and is found, associated with the car-
bonate, in various parts of the world.
From the low temperature at which zinc fuses, the
reduction of calamine is easy. The ore is first cal-
cined, and is thus rendered friable; and a portion of
water and carbonic acid expelled. The roasted ore
is reduced to powder under heavy edge-runners, and
mixed with a certain proportion of charcoal or coal-
dust, and heated in earthen retorts; the carbon com-
bines with the oxygen of the oxide of zinc, carbonic
acid is evolved, and the metallic zinc is condensed in
receivers. In the neighbourhoad of Bristol and Bir-
mingham, the zinc works are supplied with ores from
the Mendip hills and from Flintshire, and the works
near Sheflield from the mines of Alston Moor. The
calamine is freed from galena by hand-picking, and
when blende is employed, it is broken into pieces of
about the size of a filbert, and roasted in reverbera—
tory furnaces, heated with coal. The roasting is con-
tinued ten or twelve hours, during which the ore is
kept stirred with iron rakes. The ore loses about
20 per cent. in weight, by calcination.
The furnace used for the reduction of the roasted

ore is shown in sectional elevation, Fig. 2391, and
also in plan, Fig. 2392, which is taken above the


Fig. 2391. ZINC srusmmc-rnnnacn. (English)
grate, and in plan,
Fig. 2393, taken ,
below the grate. __
The furnace is m
similar to that .
used in glass ' houses. Its fire- Fig. 2393.
place is raised above the ground, the grate being in
the centre, as shown in Fig. 2392; arourd it are 6
pots for containing the mixture of ore and coal. The
pots and the fire are covered in with a dome, fur-
nished, however, with an opening over each pot, for
the convenience of introducing the charge; and the
dome is surrounded by a conical hood or chimney,
containing arched openings for the convenience of
the workmen. From the bottom of each crucible
proceeds an iron tube, down which the condensed
metal passes into a vessel in which the lower end of
the tube terminates. The upper end of the tube is
closed with a wooden plug, previous to the intro-
duction of the charge; which plug, becoming con-
verted into charcoal by the heat, is sufficiently porous
to allow the vapour of the metal to pass down, but
does not allow a passage to the coal or calcined
metal. Each crucible is covered by a‘tile, firmly
secured to it by means of fire-clay; and as the distil-
lation, per descezzsum as it is called, proceeds, the
tubes are prevented from becoming choked with con-
densed metal, by passing a. long iron rod up them
from time to time. The zinc is collected in the lower
vessel in the form of drops, and the fine powder
mingled with oxide, and the whole is fused in a large
iron pot; the dross which is skimmed from the surface
is mixed with the charge for the next operation;
while'the metallic zinc is cast into rectangular ingots,
and is ready for sale. A furnace of this kind will
admit of five distillations in 14. days, during which






. "Q\
o A
\\\\ p \h its?


104:6
ZIN O.
from 8 to 10 tons of roasted ore are operated on, and
from 20 to 25 tons of coal consumed. The metal
obtained varies from 35 to 40 per cent. of the ore
treated; and each crucible lasts about 4 months. The
crucibles are prepared, annealed, and set, much in the
same way as glass—pots. After each operation, the
condensing-pipe is taken out, and the residue removed
through the hole at the bottom, the piece of charcoal
being first broken up with a rake.
Zinc is prepared in large quantities in Belgium and
Silesia,1 and is largely imported into this country.
Indeed, it may be said that the Prussian province of
Silesia and the kingdom of Belgium, together, possess
almost a monopoly of zinc for-Europe; the total effect
of the whole quantity produced in England, France,
and Germany, having but little influence on the
commerce in this metal, the manufacture in Silesia,
as in Belgium, being greatly favoured by the abun-
dance of the coal?
The smelting of‘ zinc at the Vielle-Montagne, near
Liege, differs from the English process. The ore is
a mixture of silicate and of carbonate of zinc, both
compact crystallized. The gangue, which is of clay,
occurs in cavities in the calamine. The ore is exposed
to the air for some months, when the clay, being
softened by the rain, is readily removed; or, if the
ore be very impure, it is washed in a stream of water,
by which the clay is readily removed. Two kinds of
ore are distinguished, viz. the white and. the red; the
red contains more iron than the white, but a smaller
proportion of zinc. The following is the composition
of these two ores :-
White ore. Red ore.
' I IZI-nO-u-"u-u“ Oxide of gum "" "loxygen 11‘? 8'4 2»
.IIICUIIQIIIOQO'IOI IO‘... Water and carbonic acid 22'7 20*0
Sesquioxide of iron . 5'0 18'0
100'0 100'0
The mineral, having been washed, is calcined in
f those employed in the burn-
ing of lime [see
Mommas and CE-
MENTS, Fig. 147 5].
These kilns are
heated by two fires
at the side, ordinary
pit-coal being the
fuel; they are co-
vered by an arch,
\ and from them pro-
ceedsa flue, which
opens into the kiln
by 20 openings, 00, Fig. 2394:, arranged in 41 or 5
rows, each opening being about 41 inches square, and


Fig. 2394._’zmc ROAS’EING-KILN.

(1‘ The Annales des Mines contain some elaborate notices of the
smelting of zinc in Belgium and Silesia. An excellent account is
also given in. Regnault’s C'ours de Chimie, tome 3?, and also in
Phillips’s Manual of Metallurgy.
(2) The quantity of zinc imported into the United Kingdom in
the year ending 5th January, 1853, was, zinc or spelter, 18,505 tons
6 cwt. 3 qrs. 251 lbs,'; of oxide of zinc, 787 tons 19 cwt. 2 qrs.
2 lbs. : and therewere exported, of British zinc, 1,304 tons 12 cwt;
of Foreign zincZ 5,947 tons 13 cwt. The import is free of duty.

lined with fire-brick. Near the bottom of the kiln
are 2 openings 2020' for withdrawing the charge,
which is assisted in its descent by two slabs of cast-
iron 5, inclined at an angle of 415°. The charge is put
in at the top, and the process is continuous; the
kiln being what is called in lime-burning a running
lrz'la: the large and the small lumps of ore are mixed
together so as to allow the flame and hot air to
ascend. In this roasting, the mineral loses its water
and carbonic acid, the loss being about 25 per cent.
The roasted ore is reduced to powder under edge-rum
ners, similar to those represented under OHIconY,
Fig. 566; it is then sifted, and is ready for the re—
ducing furnace. This consists of four distinct furnaces
united in one, each in the form of an arched recess,
as at F, Fig 2395, the crown of the arch being 8 feet
8 inches above the
ground. At the
back of this open-
ing is a brick wall
20 w’, inclined as
in the figure, the
front part f f’ be-
ing left open for
the insertion of the
retorts r'r. Below
the level of the
ground at e is the
fire, the smoke and
hot air from which
enter the furnace
bymeans of 4: open-
ings. Two flues
proceed from the
arch to a central
chimney c, which
consists of at divi-
sions, each of which
is furnished with
a damper cl. The
retorts are made
of refractory clay 5 znrc SMELTING-FUBNACE.
they are cylindri- (Belgian)
cal in form, but closed at one end, each being 3 feet
8 inches long, and 6-inches in internal diameters Each
furnace contains 442 retorts r r, Fig. 2395 : a retort is
also shown separately- at r, Fig. 2396, together with

Fig. 2395 .


Fig. 2396.
an adapter a, which fits into its open mouth, the
adapter being of cast—iron, conical in form, and 16
inches in length, and to this is fitted a cone of wrought-
iron m, which is about an inch in diameter at the
smaller end. There are 8 rows of retorts in each
furnace, the wall being arranged in steps, as shown
in Fig. 2395, for supporting them; the open ends of
the retorts to which the adapters are attached being
supported by 8 plates of cast-iron, fixed in the ma_
sonry, each plate being a little lower than its corre—
sponding step in the brickwork, so as to allow the
ZINC.
10437
retort to slope with its mouth a little downwards.
The spaces between the retorts in front are filled up '
with fire-clay, and the iron adapters are also made
tight with the same material. The charge of each
furnaceiamounts to 1100 lbs. of powdered calcined
calamine and 550 lbs.‘ of bituminous coal in fine
powder. The coal is slightly washed in water, and
well mixed with the calamine. The retorts and the
adapters are well cleaned out by means of an iron
scraper, and are then charged, the lower retorts being
attended to first. The charge is introduced by means
of a shovel in the form of a half cylinder, as shown
in Fig. 2397 ; and when all the retorts are charged,


Fig. 2397’
the damper at the top of the chimney is raised, and
fresh fuel added to the fire. Carbonic oxide gas is
soon evolved in large quantities, and burns with its
characteristic bl'ie flame at the mouths of the adap-
ters. After some time, the flame increases in bril—
liancy; it assumes a greenish white tint, and throws
ofl' copious white fumes. This is a sign that the dis—
tillation of them etal has commenced, and the wrought
iron conical iube is luted on. The fire should now
be steadily maintained so as to keep all the retorts
as nearly a/ possible at one temperature; the top
rows, howeier, are usually less heated than the lower
ones, and ire hence charged with an ore which is
easy of rl action—such as the red ore—”the white
and more refractory ore being contained in the lower
retorts. In about two hours the workman removes
the cast-[iron adapter with a pair of tongs, and strikes
it sharply over a vessel which contains the oxide of
zinc or cadmz'e, as it is called: the'oxide thus do-
tached is added to a subsequent charge. An assis—
tant now holds a large iron ladle under the beak
of eaci retort, while the foreman draws out into it
with an iron scraper the distilled zinc which has
accumulated at the shoulder formed by the junction
of ihe clay retort and the cast-iron tube: he also
separates the metal which has condensed in drops on
thl interior of the iron cone. The zinc in the ladle
,is‘covered by a scum of oxide, which is removed, and
tle liquid metal is poured into moulds, which form it
iito flat rectangular ingots of from 7 5 lbs. to 85 lbs.
each. The sheet~iron cone is again luted on, and the
heat being ‘maintained for another two hours, another
portion of liquid zinc is obtained. In this way the
operation is conducted from 6 o’clock A.M. to 5 19.11.,
the retorts being tapped every two hours. The
retorts are then cleaned out and prepared for a second
charge, which is worked during the night; so that
in 24 hours the two charges yield about 620 lbs.
metallic zinc, and from 30 lbs. to 4.5 lbs. of granulated
zinc, more or less in an oxidized state. By this pro-
cess the calamine yields about 30 per cent. of metal,
the residue containing about 10 per cent. in the form
of silicate of the oxide of zinc.
When a furnace ofuthis kind is first constructed or
recently repaired, the’open face of the cavity, Fig.
2395, is closed with bricks or broken retorts, and the

temperature is slowly raised to a white heat.” After
about four days the arched recess is gradually opened,
and the retorts, previously annealed at a red heat in
a separate furnace, are arranged in their places: they
receive at first a small charge of powdered ore and
coal, which is increased until the apparatus is in
proper working order. - ~ . '
The large demand for zinc-sheeting causes it to be
extensively manufactured at these works. For this
purpose the zinc ingots are melted in a reverberatory
furnace, which has an elliptical half inclined a little
towards one side, and at the lowest" point is a hemi—
spherical reservoir for collecting the fused metal: the
ingots are introduced through one @i the doors, and
piled on the highest part of the hefitbi near the fire-
bridge. The fused metal is dipped pint of the reser-
voir with iron ladles, and poured into moulds which
give it the form most convenient for rolling. The
plates thus produced are heated in a second furnace
adjoining the first, the heat being supplied merely by
the waste gases of the first, by which they acquire
a temperature of about 212°, and can thus be rolled
into sheets at the ordinary rolling-mill. It is this
method of rolling which has caused zinc to be so exten-
sively employed during the last thirty years, previous
to which the difficulty of forming it into sheets pre-
vented its application to numerous purposes. The
Vielle-Montagne Company have greatly improved the
manufacture, as was proved by the specimens con—
tributed by them to the Great Exhibition—such as
zinc in very flexible and thin sheets, zinc stamped for
a variety of uses, mouldings produced by drawing,
nails and spikes of various kinds and sizes, wire of
great flexibility, and of all numbers. This company
has also employed zinc for castings of large size, the
statue of Her Majesty Queen Victoria in the Great
Exhibition, with its pedestal, also of zinc, presenting '
a total height of 21 feet. [See Inrnonucronr Essnr,
page xcvii] At the time of the Exhibition this Com-
pany had 80 reducing furnaces at work, employing
2,640 workmen, having produced 11,500 tons of
zinc in the previous year 1850. The company have
also two establishments for the manufacture of oxide
of zinc, intended to replace the white and grey lead
in house-painting—one at Asrzz'éres, near Paris, and
the other at Valentin-Gog, near Liege.
The furnace in use inUpper Silesia for the distilla-
tion of zinc is represented at Fig. 2398. The form
of the retorts in which the distillation is carried on,
is shown in section, Fig. 2399 : the muflle u. is about
3.} ft. in length, and 1 ft. 8 in. in height: in the front
are 2 openings 00' ; in o’ is inserted an earthen tube
it" bent at right angles, and open at the lower ex-
tremity; in this tube the metal sublimes. The open-
ing 0 is used for raking. out the residual charge, and,
when not being used, is closed by‘a clay stopple, well
luted. At t is an opening in the tube by which the
charge is introduced with a semi-cylindrical shovel.
This opening is also closed during the distillation with
a clay stopple. From 6 to 10 of these muffles are
arranged in 2 rows on either side of the central fire-
place. The arched openings in the furnace are closed
10418
by means of iron plates when the muffies have been
properly arranged; these plates prevent the too rapid
cooling of the bent tube it’, but a small door at d,
Fig. 2398, can be opened when it is required to intro—
i‘.

Fig. 2398. znvc smnL'rms-Funnacn. (Silesiam)
duce a charge into the mutile. The grate is shown at
G, pit-coal being the fuel. The charge consists of
equal bulks of roasted calamine (in pieces of about
the size of a pea) and fine cinders from the grate, the
latter being preferred to fine coal, the distilled pro- k
W


h; ll“
‘ g{pageraspy?i
ill-‘ill‘lllllll
Fig. 2399.
ducts of which are apt to choke up the bent tube 2,‘.
The preparatory process of roasting the calamine may
as carried on in a separate furnace by means of the
waste gases proceeding from the muffles. The reduced
zinc escapes from the open end of the bent tube into
vessels placed in openings 0 0 of the furnace, Fig. 2398.
Each operation is continued for 241 hours, and the re-
sidue is removed after every third distillation.
Zinc is largely used in the manufacture of brass,
and also for making baths, water-tanks, spouts,
pipes, plates for the engraver, for roofing, for voltaic-
batteries, for covering iron, for sheathing for ships,
and for many other purposes. Zinc tiles are
remarkable for their lightness. The zinc of com-
merce is never pure, but is contaminated with lead,
cadmium, iron, copper, &c.; but by dissolving it in
sulphuric acid, ‘filtering the solution, decomposing it
with carbonate of potash, washing the precipitate,
and heating it with powdered charcoal in an earthen
or iron retort, the metal pure, or nearly so, may be
distilled over into a vessel of water: the neck of the
retort must be short and wide, to prevent the con-
densed metal from choking it up.
Zinc is of a bluish white colour, and its recent
fracture presents a brilliant, crystalline surface. It
is somewhat brittle at ordinary temperatures, but
when heated to between 212° and 300° it becomes
malleable and ductile, and may be rolled or hammered
out without fracture; and, what is remarkable, it

\
ZIN G—ZIRCONIUYL
retains its malleability when cold: the sheet zinc cf
commerce is made‘ in this way :-—If the heat be in-
creased to about £50", the metal again becomes
brittle, and may be reduced to powder in a mortar.
Zinc fuses at about ‘773°, and by slow cooling exhibits
a lamellar crystalline texture. At a bright red heat,
zinc boils and volatilizes, and if air be admitted it
burns with a vivid whitish bhie light, generating the
oxide, a white floculeut matter, called by the older
chemists Zaaa pliilosopliioa, or philosopher’s wool.
Zinc is readily dissolved by dilute acids, and is used
in preparing hydrogen gas. [See HYDROGEN]
Oxide of zinc, ZnO, the only oxide of this metal, is
a powerful base, isomorphons with magnesia: it is
a white tasteless powder, not scluble in water, but
freely so in acids: it becomes yelbw bysheat. When
prepared by the combustion of the metal, it always
contains small grains of the metal 5 but it may be
purified by levigation. This substaace has been pro-
posed as a white paint instead of white lead, and has
been largely manufactured for the purpose, in which
case it is prepared by burning the metal, as it is first
evolved from its ore in the reduction process. The
objections to its use are stated in the lnrnobucronr
ESSAY, p. cxxxvi. .
Sulphate of zinc, or wlziie vitriol, ZnOS03,+7HO,
is prepared by dissolving the metal in d\lute sulphu~
ric acid, or more economically by roasting the native
sulphuret, or blends, which by absorbing txygen be-
comes to a great extent converted into tle sulphate
of oxide: the mineral is then thrown into hot water,
and the salt is obtained by evaporating the clear solu~
tion. This salt closely resembles sulphate oi magnesia
in appearance; it has an astringent metallict ste, and
is sometimes used as an emetic : the crystals are more
soluble in cold than in hot water. This sall forms
double salts with the sulphates of potash and am-
monia.
CarooaaZ‘e of ziae, ZnO,002, is found natire, as
already noticed. The white precipitate, formel by
mixing solutions of zinc and of alkaline carbonater, is
a combination of carbonate and hydrate.
Chloride of‘ zinc, ZnCl, may be readily prepared \iy
dissolving zinc in hydrochloric acid. It is translucelt
and fusible, nearly white in colour, very soluble ,1;
water and in alcohol, and is very deliquescent. A
strong solution is a convenient means of obtaining a
graduated heat above 212°. Chloride of zinc com-
bines with sal-ammoniac, and with chloride of potas-
sium, to form double salts: the former, prepared by
dissolving zinc in a proportionate quantity of hydro-
chloric acid, and then adding an equivalent of sal-
ammoniac, is useful in tinning and soft-soldering
copper and iron. [See Sommnrna]
The zincing of iron, &c., is briefly noticed underELEc-
TROMETALLURGY, and also more fully under AMALGAM.
ZIRCONIUM (Z3. 23), a rare metal, the oxide of
which, Ziroom'a, ZrO, is found in the Zireoa, or Zargoiz,
and a few other minerals. The zircon is found in
Ceylon, and when colourless and transparent, it is
classed among the gems: when of a brown or red
colour it is known as lig/aeiatiz or jaoiafli.
'SH'IEWCL 'IHJHSII
6701
TABLE I.-—FOR
USEFUL TABLES‘
- a r
CONVERTING FRENCH DECIMAL MEASURES ANI) WEIGHTS INTo ENGLISH MEASURES AND WEIGHTS.
A. MEASURES 0E LENGTH.
\
- 1 2 3 1 A 5 6 7 8 9
METRE—English Yards 109363 2187 27 328090 137153 516816 656180 765513 871906 981270
,, Feet . 328090 656180 981270 1312360 1610150 1968539 2296629 2621719 2952809
,, Inches . 3937080 7871158 11811263 15718315 19685391 23622173 27559552 311 96630 35133709
DECIMETRE.--Feet . 032809 065618 098127 131236 161015 196851 229663 262172 295281
Inches 393708 787116 1181121 1571832 1968539 2362217 27 '55955 3119663 3513371
.OENTIMETRE.--Inehes . 039371 078712 118112 157183 196851 236225 275596 311966 351337
f JVIILLIMETRE—Inches 003937 007 871 011811 015718 0 19685 023623 027 560 031197 035131
B. MEASURES OF CAPACITY.
1 2 l a | a s e 7 s 9
CUBIC OENTIIIETRE.—-Oubie Inch 006103 012205 018308 021111 030511 036616 012719 018822 051921
LITEE.--English Imperial Gallons 022017 011033 066050 088066 1 110083 132100 151116 17 6133 198119
,, ,, Qnarts 088066 176133 261199 352266 110332 528398 616165 701531 792598
,, ,, Pints . 176133 2 52266 528399 701531 880661 1056797 1232930 1109062 1585195
STERE—Gallons . . 22016613 11033287 66019930 88066571 1100-83217 1320-99860 151116501 17 6133117 1981197 91
O. WEIGHTS.
1 2 3 1 5 6 7 8 9
KILLCGRAIIHE—Cwt. . . . 001970 003939 005 909 007 87 9 009818 011818 0137 88 0-157 58 0 17727
1b. gavoird.) . 220186 110971 6 61157 881913 1102128 1322911 (‘1513100 17 ‘63886 1981371
KILL0GRAMME.—-1b. troy) . 267951 5 35903 803851 1071805 13397 57 16 07708 1875659 2113610 2111562
GRAMME.--Grains . . 1511212 30 88181 1632726 6176968 7 7 '21210 L 9265352 10809691 12353936 138981 7 8
DECIGRAMME.--Grains . 151121 3 08818 163273 617 697 772121 926535 1080969 12 35391 1389818
GEN'l‘IGRAMME.—~Gl‘€lill$ . . . 015112 030885 016327 0617 70 O7 7212 092651 108097 123539 138982
MILLIGRAMMn—Grains . . . . . . 001511 0 03089 001633 0 06177 007 7 21 009265 010810 012351 013898











These tables are given in Gmeliu’s Chemistry, vol. ii. (Cavendish Society’s Translation.) They are arranged on the same plan as the Analytical Tables in Rose’s
Analytical Clzemz'sh-y, and other works of similar character. One example may suflice to Illustrate the mode of using them. Let it be required to find how many grains
[By Coliimn 8 line 1 of Table 0, we find: 3(7)‘
are equal to 87‘135 grammes :—--
“WE-<1
Q9015;
3,
Z’, '1
‘,, '03
,, m5 ,,
i grammes
___-___
87'135~grammes : 13502080
12353930
1080969
61770
01633
007 7 2
II II II II ll
grains.
;
1050
‘ USEFUL TABLES.
TABLE IL—BARQMETER 801m IN MILLIMETRES AND INCHES.




Mm In. Mm. In. Mm. In.
700 = 27560 780 = 28741 760 = 29922
701 = 27590 781 = 28780 761 = 29961
702 = 27688 782 = 28819 762 = 80000
708 = 27'678 788 = 28859 763 = 80040
704 = 27717 784 = 28898 764 = 80079
705 = 27756 785 = 28988 765. = 80119
706 = 27795 786 = 28977 766 = 80158
707 = 27885 787 = 29016 767 = 80197
708 = 27876 788 = 29056 ' 768 4 = 30237
709 = 27 914 789 = 29095 769 = 8027 6
710 = 27958 7 40 = 29184 770 = 80815
711 : 27'992 741 = 29174 771 = 80,855
712 = 28082 742 = 29218 772 = 80884
718 = 28071 748 = 29252 773 = 80484
714 = 28111 7 44 = 29292 7 7 4 = 80478
715 ':= 28150 745 —__.—~ 29'881 775 = 80512
716 : 28'189 746 = 29871 776 = 80552
717 = 28229 747 = 29410 777 = 80591
718 = 28268 748 = 29449 778 = 30-681
719 : 28'808 749 = 29489 779 = 80670
720 : ,28'847 750 ''=“" 29528 780 = 80709
721 = 28886 75]. = 29567 781 = 80749
722 = 28426 752 = 29607 782 = 80788
728 =: 28465 753 = 29646 788 = 80827
724 : 28'504 754 = 29685 784 = 80867
725 : 28'548 755 :1 29725 785 = 80906
726 = 28588 756 = 29764 786 = 80945
727 = 28622 757 = 29804 787 = 80985
728 = 28661 758 = 29848 788 = 81024
729 = 28701 759 = 29882 789 = 81068
28 inches = 711187 millimetres.
29 ,, = 785587 ,,
80 ,, = 761986 ,,
81 ,, = 787886 ,, "
1 millimetre = 008987 inch. 1 111011 = 2589954 millimetres.
0'1 ,, = 000894 ,, 0'1 ,, = 258995 ,,
0'01 ,, = 000039 ,, 0-01 ,, = 025400 ,,
0 001 ,, = 002540 ,,



I
TABLE llL—Fon CONVERTING DEGREES OF THE CENTIGRADE THERMOMETER INTO DEGREES on
FAHRENHEIT’S SCALE.

fir
Cent. Fab. Cent. Fah. Cent. Fah. Cent. Fahd
--100° - 148'0o -- 85° 121'0° —- 70° -- 940° — 55Q -- 67'0"a
99 . . . 1462 84 . . . 1192 69 . . . 922 54 . . . 65'?
98 . . . 1444 88 . . . 117‘4 ~M68 . . . 904 58 , . . 684
97 . . . I 1426 82 . . . 115'6 ~67 . . . 886 52 . . . 616
96 . . . 1408 81 . t . 1188 66 . . . 868 51 . . . 59 8
95 . . . 1890 80 . . . 112'0 ' 65 . . . 850 50 . . . 58'0
, 94 .. . 1872 ,~ _ 79 . . . 1102 l 64 832 49, . . . 562
98 \ 1854 I l$78 108'4 ' 68 814 k‘ _' d 48 544
92 . . . 188'6 _ 1 77 1 . . .' 1066 ~ 62; 1. . . 796 147 . . . 526
91 * 1818 '176 1048 i; '61; 77'8, '‘ 46 ‘r‘ .. ' 508
90 . . . H 1800 . :75 . . . _ 1080 I ,- 60’ I; .1. 76'0 " “I 45 :7‘. . 1 49-0
89 . . . 1282 i 1 ~74 - . . . 101'2 ‘ 59 .’.i. 742; Q j 44 r; . . I 472
88 . . . ~ 1264 a 3 -7i§ ~ . . .'. 994 j I 58 z * , 724 I? :, 48 ; 454
87 . . . 124‘6 ‘ lg — i712 w. . .; 976 g t 571: 5 1 70'6:_ :2 \ 42 ; 48'6
, 86 ... 122s v‘ "71 *1. .“ 95-8 : 1'4 se~ 1 68-8» 1-1- 41 , 41-3
'su'raivr. rmuasn
1901


9 011 ' ' ' 666 0068 ' 091 ‘17-001 80 886 96
8881' ' ' ' 966 6818 091 91.01 ' ' 60 0—66 96
068‘? ' 966 ‘it-918 891 8961 ' 10 696 ‘1’6
698% ' ‘1166 9118 691 0901 00 17-86 86
68817 ' 8'66 8-618 991 6-601 08 9-16 66
9-1815 ' ' ' 666 03118 991 11-001 ' 88 8-09 16
80615 ' ' ' 166 6-008 ' ' ‘1791 9-881 ' ' 68 0-89 06
0-8611 ' ' ' 066 ‘17-608 891 8981 ' 98 6-99 01
6961? ' ' ' 016 9-908 691 0981 ' 98 13-99 81
‘17-1-61? ' 816 8808 191 6881 ' 118 9-69 61
9-66’9 ' ' 616 0-608 ' 091 ‘17-181 ' 88 8-09 91
1 806? ' ' ' 916 6-008 611 9661 ' ' 68 0'69 91
0-6117 ' ' ' 916 1806 811 8-661 ' ' 18 6-69 11
66117 ' ' ' ‘516 9-966 6111 0-961 ' 08 $99 81
‘17-9117 ' ' ' 816 81706 ' 9171 61761 ' ' 06 9-89 61
9-8117 ' ' ' 616 0-806 ' 911 ‘17-661 ' ' 86 8-19 11
8115 "' 116 6106 111 9061 ' 66 009 01
0'01? ' ' ' 016 1686 8111 8891 ' ' 96 68'? 6
6801? ' ' ' 606 9-686 6171 0-691 ' 96 891 8
8901' ' ' ' 806 8-986 1111 6991 ' ‘176 9191? 6
9 17017 ' ' ' 606 01186 0111 ‘17-891 ' 86 8617 9
86017 ' ' ' 906 6686 681 9-191 ' 66 0117 9
0-10’11 ' ' ' 906 17-086 881 8-091 ' 16 6-08 ‘17
6008 "' $06 9866 ' ' 681 (1891 ' 06 ‘868 8
‘17-608 ' ' ' 806 8966 ‘ 981 6 991 ' ' 09 9-98 6
9 908 ' " 606 0966 981 ‘fl-1791 ' ' '89 8-88 1 +
8808 ' ' ' 106 6866 ‘981 9-69[ ' 69 0-68 0
0-608 ' ' ' 006 ‘17-166 ' 881 8091 ' 99 6-08 1
6-068 ' ' ' 001 9696 ' 681 00171 ' 99 F586 6
‘8888 "' 801 8696 181 6691 ' 19 £196 8
9-988 ' ' ' 661 0-996 081 17-9171 ' ' 89 8176 ‘f7
8988 "' 901 6996 061 51891 ' 69 (186 9
0-888 ' ' ' 901 17-696 861 81171 ' 19 6-16 9
6188 "' 101 9096 661 0091 ' 09 ‘601 6
‘V068 801 8896 961 6881 ' 09 961 8
9668 601 0696 ' 961 ‘V981 ' ' 89 891 0
8968 ‘101 6996 161 11181 ' ' 69 091 01
01768 061 11-896 861 8681 ' 99 6-61 11
6668 081 8196 661 0-181 ' 99 ‘17-01 61
19-068 881 8016 161 6-061 ' ‘179 9-8 81
9898 681 0896 061 ‘V661 ' 89 84) $1
8998 981 69176 011 9-961 ' 69 0-9 91
0-998 981 ‘WW6 811 8-861 ' 19 6-8 91
6-898 ‘1781 96176 611 0661 09 ‘19-1 61
‘8198 ‘ 881 8016 911 6061 6? ‘60 81
9-698 ’ 681 0686 911 17-811 819 6-6 61
8698 ' 1'81 6-686 ‘511 9911 6'17 017 06
0-998 081 ‘1986 811 81711 917 8-9 ' 16
6998 061 9886 611 0-811 917 9-6 ' 66
1-698 861 8186 111 6111 117 17-6 ' 86
9 098 ' 661 0-086 _ ’ 011 ‘8001 81 611 ' ‘96
88178 961 6866 -' 601 9601 6'17 081 ' 96
06198 961 ‘17-966 801 8901 1? 8-151 ' 96
69178 J ' ' ' ‘1761 91966 601 01901 01 9-91 ' 66
88198 ' ' ' 861 8666 t 901 6-601 08 \ 1-81 ' 86
9-198 ' ' ' 661 0166 901 ‘17-001 88 6-06 66
8088 ' ' ' 161 6616 ‘1901 9-80 68 0-66 08
0-888 ' ' ' 061 ‘19-616 801 8-90 98 8-86 18
6-988 ' ' ' 691 9-916 601 0-96 98 9-96 68
‘6988 "' 891 8816 101 686 " 98 ‘666 88
9-688 ' ' ' 691 0-616 001 ‘816 88 666 $8
8088 ‘ ' ' 991 6-016 00 9-68 68 0-18 98‘
0668 "' 991 ‘6806 80 868 18 868 98
6668 ' ' ' ‘V91 9-906 60 0-98 08 9-18 68
‘17-968 ' ' ' 891 8906 90 6178 66 ‘5-98 88
9-868 ' ' ' 691 0-806 ' ' ' 96 15-68 ' ' ' 86 6-88 68
88168 + ' ' ' 8191 + 06106 + ‘ ' ' ‘176 't' 09-08 + ' ‘ ‘ 066 '1‘ 00-017 001 ""
'uvu sues ‘use aueo ‘use wuss ‘use iueo





(‘ram-woo) ‘1111 urrava;

1052
USEFUL TABLES.
\
‘r
TABLE III. (continued)

Cent.
Fall.
\
\
Cent.
Fah.
Cent.
Fah.
Cent.
Fah.
229
230
231
232
233
239
- 235
. 236
237
238
239
24-0‘
2441
2412
2413
24.4
2455
2446
24:7
2448
2419
250
251
252
253
254.-
255
256
257
+ 228° + 449-40
444-9
446-0
* 4478
449-6
451-4
. 458-9
455-0
4568
.... .. 458-6
. 460-4
469-9
464-0
. 465-8
. 467-6
469-4
4712
478-0
474-8
.476-6
-- ,478-4
. 4809
489-0
488-8
485-6
487-4
. 489-9
491-0
499-8
494-6

-+258° .
259
260
261
262
263
264!
265
266
267
268
269
270
271
272
273
27 41
275
976 I"
277
279
280
281
282
283
2841
285
286
287
288
978 I"
-. . + 419640
44982
5000
5018
. 5036
50544
5072
5090
5108
5126
514944
5162
5180
5198
5216
5234:
. 5252
1 5270
.. .. 528‘8
. 530'6
532'44
. 53442
5360
5378
5396
54:14:
54832
54450
. 54468
54886
5504:
+ 289° ,~.

290
291
292
293
299
295
296
297
298
299
300
301
302
303
304!
305 . . .
306_ . . .
307
308
309
310
311
312
313
319
315
316
317
318
319
o n o ~ , .
' Q U a u 0
.. +
" 1555-8
55229
5540
557-6
559-4
561-9
568-0
564-8
566-6
568-4
570-9
579-0
578-8
575-6
577-4
. 5792
5810
5828
. 58416
58641
5882
5900
5918
I 598-6
595'4:
. 5972
5990
6008
6026
604544
6062

+320°
321
322
323
329
325
326 I. . .
327 .
328 .
329 .
330 .
331 .
332 .
333
3344
335
336
337
338
339
340
341
392
3413
344.-
3445
3466
847 .III
3418
3419
O .5 t o
O I i 0
’ D v v
I O: ‘ a
‘.h.‘
I'I. . 688-6
+ 60800
6098
6116
61341
6152
6176
g . 618'8
.’. .. 620'6
622'41
62452
6260
6278
6296
6314
6332
6350
6368
.. 64,041
. 64622
641480
64458
64176
64,941
6512
6530
65458
6566
65841
6602

TABLE IV.—-TH_E Pnoroarron BY WEIGHT or ABSOLUTE on BE
DIFFERENT Srn crrrc Gnxvrrrns. (Fozoaea)
41.,AL00H01. IN 100 rxnrs or 8291161128 or
‘a
r ° . .8 ° . or . . ° '7 . Gr. at 60°‘ Per cent eof
Spzfieftff’ 11135358155? Shiite "8?? 354325581531’? 853236;” 35.533333? 81215-5- 6). - 9414138581.
0-9991 0-5 09659 - _, 95" 0-9184 50 018603 75
0-9981 1 09688 96 09160 51 08581 76
0-9965 9 0-9698 97 0-9185 . 59 98557 - 77
0-9947 8 0-9609 98 09118 ' ' 53 {0,8533 78
09980 4 0-9598 99 09090 54 0.8508 79
09914‘ 5 0-9578 80 0-9069 55 ‘0.84183 0-9898 6 0-9560 81 0-9047 56 0.8959 82
0-9884 7 0-9544 89 09095 57 0,8519%
09869 8 0-9598 88 09001 58 0 84-08, 0-9855 9 0-9511 84 0-8979 59 (58382
09841 10 0-9490 35 0-8956 60 ~0 83,57. 8%
0-9898 11 09470 86 08989 61 018,351 2
09815 19 0-9459 87 . 08908 69 0.8505 g
0 9809 18 09484 38 0-8886 68 0927 9 29
09789 14. 09416 89 08868 64, 0.8254 0
09778 , 15 0-9896 40 08840 65 98288 9
0-9766 16 09876 41 08816 66 0.8199 9%
09758 17 09856 49 08798 ,67 0.2179 33
09741 18 ,Qg9335 48 08769 68 0. 143 94!
0-9798 19 999814 44 087.45 69 0.811 95
09716 90 09999 45 99791 70 08089 96
09704 91 09970 46 : 08696 71 08091 97
09691 99 09949 47- 08679 72 0.8031 98
09678 98 09998 48 08649 72 ,99
09665 94 09906 49 08695 7 07938 L’ ‘who:

in. CLAY, PRINTER, BREAD s'rnnnr HILL, LONDON.


.(3 N ‘$13135 a‘ ,1. v .15.’ r . a
.1 ...n} we...’ i , . . iii?“
1, ,_: U ‘a
17.. .
;.... F:
.x
".14..
fine! a A
m .
2mm
.. A . . , v 7 tan
Gun? 1 . . v , , , , v , . . a»,
A. , . v . . . we
. Wemflwwu
: v
KS. .5193»?
v5 “iii;
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i.
f
. an. a a ..P i A a ,
nvk t: 4.
at“; it‘
.. in.‘
a
flirt
fill».
fr)»
, 72113:; w
..
“tn/SJ
12%: 13:1.
AIMS; Warazrfw
5,».
>129‘
1.1 Idea‘
131:1,- >. {>1
..1
. Kw
nvamlw 50" 1115x3111
i x
All _tlr r "in ‘A , and".
1.. 5
w
. .2
..wk
£611.17 Mr,
a...»
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1
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MW’,
‘at, "@424.
5.. .. vi
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the“
a ,6 . EX; 7 A a?
we...‘ , 7 ‘2T1 . .
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I ..... ,7 v. v .. v v . v v . ..~ .. v , . i. . . .., A‘ , . (Q .
.L a . .
1a. 7 KIM»:
flay . . r
.~ p , x “fin. W;

an .. a» 1%
a: .. ..
w
' ‘may’:
V; ,n
21%, a. i 7'
I
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